Sunday, September 30, 2012

**ALERT** New Model Forecast Projecting 18''+ For Minnesota

The latest 18z GFS model is projecting over 18 inches of snow to hit northern Minnesota in the next 120 hours, bringing a potentially significant snowstorm to start the first full month of fall.

It should be noted that the GFS is the strongest model with this system, so this probably will not happen. However, this is quite interesting, as amounts are increasing as we head closer to the event itself.

More on this developing situation tomorrow.


First Snowstorm Of Season Appearing Likely For Upper Midwest

This latest 120-hour snowfall forecast off the 12z GFS from Wxcaster is indicating that the first snowstorm of the season will be upon the Upper Midwest.

The GFS model is indicating that up to 6 inches of snow may fall in extreme northern Minnesota, with as much as a foot or more hitting parts of south central Canada. This first snowfall event is rather early as a whole for the nation, and many may be unprepared. Spread the word if you are in the zone for possible snowfall, especially to those with young children or those who may be elderly or disabled. Just as heat waves can kill, cold can kill those at high risk, such as the young and old.



The cold weather is coming, and coming fast. The latest ECMWF is showing very cold 850mb temperatures across the North Plains, pushing into the nation following a cold front that is entering the central Great Lakes and Ohio Valley at the time of this image.

If the ECMWF is to be believed (and it should be), the coldest air of the season is only days away. This would mean that the first two weeks of October should be met with more people wearing jackets and long-sleeved shirts than in the last few weeks.
You may be thinking that the models are probably just overestimating this event, but the scenario has some backing to it.

The East Pacific Oscillation (EPO) and Arctic Oscillation (AO) both plummet to the negative phase in the first week of October, setting the stage for a very cold period for the second and third weeks of October. When the EPO is negative, we commonly see a cold period across the east US and warm conditions in the West. With the negative AO, the north and east US get cooler than normal. These two combined will enable colder than normal air to set up across the region.
However, Halloween is looking like it will not be as cold as the next couple of weeks will be, as the EPO looks to rise back to a more positive phase.


South-Central Severe Weather Update

This is an update concerning the ongoing severe weather situation in the south-central US.

Above is an analysis chart, depicting current conditions across the region. Looking at the panels, pressure tendencies have been falling in the past few hours, indicating a strengthening of the system. High dewpoints in the area, combined with temperatures hovering immediately around those dewpoints should make for an unusually wet situation, as such a slim margin between the two brings about enhanced concerns for flooding.

On the bottom right is the latest observed wind field. We can see very tight wrapping of the winds spread across the region, with surface winds surpassing 20 MPH in some areas. Offshore, in the immediate vicinity of a particularly strong band that is moving to the north is producing winds above 40 MPH, making for a dangerous situation for workers on the oil rigs.

The lack of available energy for the storms is observed on the bottom left. However, with this lack of instability, the potential for flooding rains lessens, which is good for those already hit hard by Hurricane Isaac in the last several dozen days.


Saturday, September 29, 2012

Nadine Closing In On Longest-Lasting Atlantic Tropical Cyclone

"Hurricane Nadine? I thought she was gone!" You might be thinking this. But, Nadine actually reformed a while back, and has been chilling out in the Atlantic as a hurricane. As of now, it is a Category 1 hurricane, and is no threat to North America. However, Europe may be at risk.

The image above shows the forecast track probability off the 0z GEFS for Nadine. The consensus is next to nothing, but the models appears to move northwest before making a loop and moving east-northeast. From there, the models drop off in a wild spread.

This unknown track comes as Nadine closes in on the longest-lasting tropical cyclone record in the Atlantic. The record is 28 days, and is held by Hurricane San Ciriaco from August 1899. This is no 20 year record, we're talking over 2 centuries that this record has stood. Nadine is currently at 18 days, just a week and 3 days shy of tying the record.

Looking at the models, it looks like Nadine may die off if she is to move northeast into a less favorable environment. Should this happen, Nadine would probably break the Top 10 chart of longest-lasting tropical cyclones in the Atlantic. Number 10 is a 19.25 days (1 day above Nadine) in September 1893, held by a storm called 'Storm 9'.


Snow May Fall In Midwest As October Begins

RED: 1000-700mb = 2840m CYAN: 850-700mb = 1540m YELLOW: 1000-850mb = 1300m PURPLE: 700-500mb = 2560mGREEN: 850-500mb = 4100m WHITE: 1000-500mb = 5400m BLUE: 850mb 0°C Isotherm
There appears to be a possibility for some snow on the morning of October 8th in the Midwest, possibly as far south as Chicago, IL and Gary, IN.

The latest GFS model forecast is showing critical thickness values on the left half of the image above. Critical thickness is a term used by forecasters to deem whether the air is cold enough for snow. Any precipitation above a critical thickness line may be snow- the more critical thickness lines are south of precipitation, the better snow potential there is.

This potential snow event looks to be in the early hours of Monday, roughly around 1 AM central time. All thickness lines, minus the yellow 1000-850mb thickness line, are south of the projected precipitation. Now, this could very well be cold rain or a slight ice event, but I think that cities like Milwaukee have a shot at flakes flying, while Chicago has a lesser potential for such activity. Not a zero chance, but less than areas to the north.

The 6z GFS does show some very slight accumulations in central and southern Wisconsin, but nothing major.


(Caption copy-pasted from COD-NexLab)

Coldest Weather Of The Season On The Way

The Earth Systems Research Laboratory (ESRL) and the National Centers For Environmental Prediction (NCEP) are agreeing on a strong negative EPO going into the first week of October, something that could have major implications on temperatures.

The East Pacific oscillation, or EPO, has a positive and negative phase. In the positive phase, a stormy pattern in the West and warmth in the East is a common sight. However, these two agencies are both predicting a very negative pattern. This would lead to an enhanced potential for cold air to work its way into the East, while high pressure sets up across the West.

The Arctic Oscillation, another major factor in bringing cold air to the States, looks to be dropping negative going into the first week of October. This negative EPO, combined with the negative AO looks to be a perfect storm for some cold weather.

These two indices look to produce a very chilly first week of October for the East. I would not be surprised to see cities like Chicago, Milwaukee, or possibly Indianapolis reaching into the 30's, possibly getting below freezing at times.

You heard it here first at The Weather Centre!


Southern Canada May See Aurora Tonight

A flare released by the sun yesterday is expected to make impact with the Earth in the next several hours, producing the chance for widespread auroral viewing across southern Canada, and possibly areas in the extreme Upper Midwest.

The Planetary K index has not yet risen to high values, so we do not know how strong the aurora will be or how far south it will stretch. I will have a much better feel on this by tonight, and will issue a post concerning the aurora's extent by then.

Persons with jobs in the electrical, astronautical or those residing in the higher latitudes should be aware of possible damage to transformers, corrective orbital action needed for satellites affected, and power loss in higher latitudes.


Friday, September 28, 2012

SOI Remains Erratic; El Nino Not Evident

The Southern Oscillation Index, commonly called the SOI, remains too erratic and unsteady to provide clear evidence that an El Nino is present.

This roughly-2 year chart of the SOI shows that the La Nina was very well defined in summer-fall-winter 2010-2011, and even in 2011-2012. However, as of recently, the SOI has been all over the place. It has mainly been in negative territory, but the fact that it is usually above -8.0 (the threshold for an El Nino is -8.0 or below) during the last few months tells me that the SOI is not recognizing the presence of an El Nino.

I believe that this winter will hold a neutral ENSO, possibly warm neutral (above 0.0 but not above 0.5) . I have yet to nail down exactly the analogues appropriate for that situation, but I will find it and give it to you ASAP.


Special: Why Was This Hurricane Season Active?

This is a special report by The Weather Centre.

This summer was an El nino summer, and in an El Nino, tropical winds turn to a point that drives down Atlantic activity, and raises Pacific tropical activity. However, as shown in this post, the Atlantic is currently above normal. So why is this happening?

I would like to introduce you to the AMM, or the Atlantic Meridional Mode. The AMM, in a nutshell, is traced in either a positive or negative phase. In the positive phase of the AMM, tropical activity in the Atlantic is above normal. In the negative phase, below normal activity is observed.

Let's take a look at recent statistics of the AMM over the past through years. Screenshot courtesy of the ESRL.

The chart shows months vertically, one column for each month. The circled part is the last 3 months of the AMM. See how it has recently spiked positive after a negative winter. As of the latest August tally, the AMM ended up above 2.00, indicating the AMM is well into the positive phase.

I expect enhanced Atlantic tropical activity to continue, as the AMM takes time to switch phases. However, as we edge into fall, this possibility is slowly dwindling.


Thursday, September 27, 2012

Mars Curiosity Rover Finds Ancient Water Evidence

NASA's Mars Curiosity Rover has found evidence of ancient water on the surface, as shown in the image above.

The circled part of the image is assorted bedrock, called sedimentary conglomerate in the geological world. The area, named 'Hottah' for Hottah Lake in the Northwest Territories in Canada. Hottah has pieces of gravel that are shaped in a formation that is round, indicating kind of a sanding-down of the material. Similar to when you see a rock that is round and smooth, these pieces of gravel are also smooth. This smoothless and round shape indicates that a water stream did affect these pieces of gravel.

This is a crucial piece of evidence, that may very well lead to another significant discovery on Mars.


Watch For Strong Trough In West Coast

The latest GFS model is projecting an extremely strong trough to hit the West Coast in the beginning of October, continuing the unusual-ness to this weather year.

This is indeed long range, and should be taken as such. However, should this system happen to strike, we could be seeing very unusual weather in these regions. Looking at the same timeframe, it has come to my attention that a small air mass suitable for snow will be over the waters to the west of California. This does NOT mean snow will fall, but does mean that, if the surface were colder, snow could fall there.

Wednesday, September 26, 2012

*LAST CHANCE* Sign Up For Personal 2012-2013 Winter Forecast

This is your LAST CHANCE to sign up for a Personal 2012-2013 Winter Forecast.


You can get a PERSONAL 2012-2013 Winter Forecast for your town!

Here's how to sign up:

-Comment on this post with your town.

That's it! No name or email required- this is done anonymously. All you have to do is comment your town. I will give plenty of notice on when these personal forecasts will be released.

This is your LAST CHANCE to get your VERY OWN 2012-2013 Winter Forecast. Sign up NOW!


Tuesday, September 25, 2012

Final 2012-2013 Winter Forecast Release Date


The release date for the FINAL 2012-2013 Winter Forecast will be SATURDAY, NOVEMBER 3 at 12:00 PM Central Time. I am setting the date, as the indices I took a look at today made a result similar to having all the puzzle pieces falling into place. Never before have I been as confident in a long range forecast as I am now, and this confidence will only grow as we go forward towards the release date.

BY THE WAY- Personal winter forecasts will be issued in November as well, but the exact date is unknown. It is likely they will be issued before Thanksgiving.


Monday, September 24, 2012

El Nino Is (Temporarily) Dead

The latest sea surface temperature anomalies across the Equatorial Pacific indicate that the El Nino has dropped off and disappeared, temporarily making this El Nino dead.

The reason I say temporarily is because underwater anomalies are still in an El Nino stage. However, these warm waters are not near the surface and are several dozen meters below the surface. As I have been saying for the last week or more, this El Nino is struggling, and this only continues to prove my case that the El Nino is dying off.

I believe that we still are in an El Nino, only because this is the first update that shows no warm SST anomalies. However, if the same scenario is shown next week, the probability of a neutral winter will skyrocket in my eyes.

ENSO monitoring regions are still hovering around positive-neutral temperatures (just below 0.5 degrees above normal), so we know that the El Nino is not completely killed off. However, this is a big step as far as the potential for a neutral winter, possibly hinting at a La Nina into spring or summer.


Weather Watchers: Another Windy Day In The Midwest, South Plains

What appears to be a third day of wind has arrived for much of the Midwest, and even a portion of the Southern Plains today.

Wind speeds have been clocked as high as 26 MPH on the northern Minnesota/Wisconsin border this afternoon, while bigger cities like Chicago and Milwaukee only have gotten as high as 18 MPH. Regions closer to the Great Lakes are getting even windier, with the upper portion of Michigan getting as windy as 24 MPH.

Even the Southern Plains are getting in on the fun. Central Oklahoma has maxed out at 17 MPH for the afternoon. However, the northwesterners in Texas can attest to 18 and 20 MPH wind reports, equal to that being observed in the Midwest. The lack of a fairly large body of water brings down the reports in Texas from that of upper Michigan, where water enhances the wind speed, as land does not interrupt the wind.


Negative QBO Helping Prospects For Negative NAO In Winter

I have been watching the QBO and found that both monitoring levels (30mb and 50mb) have been trending negative. This bodes well for the possibility of a negative NAO this winter.

But first, WHAT IS THE QBO?
QBO (Quasi-Biennial Oscillation): The QBO is an indice measured in two levels of the atmosphere. These two levels are the 30mb and 50mb levels, and are measured by the direction and strength of winds in those levels. For instance, the POSITIVE QBO is found in WESTERLY winds, while the NEGATIVE QBO is composed of EASTERLY winds.

Recent measurements of the QBO at both the 30mb and 50mb levels are negative, indicating easterly winds. The presence of both levels recording negative values tells me this is not a quick change from positive, but a trend.

The QBO has a big impact on the North Atlantic Oscillation. Without getting into the technical stuff, just know that a negative QBO can help enhance the negative phase of the NAO. Let's take a look at what the NAO has been doing recently.

Look how negative the NAO has been recently, with only 3 or 4 jumps into positive territory in the past  4 months. 2 of those 'jumps' into positive territory were minimal strength! 

Could the QBO be to blame?
Most certainly! The QBO has been very negative for much of the time the chart above was recording (June 1 to present). But the QBO is not alone. The AMO also helped, the effects of which were seen in this recent post. The presence of a positive AMO has helped to warm the waters in the north Atlantic. 

It's like all the pieces are coming together for the Northeast. Will this be the year of winter's revenge? It's certainly shaping up that way.


Positive AMO Should Enhance Negative NAO This Winter

The presence of a strengthening positive-phase AMO, or Atlantic Multidecadal Oscillation, indicates that the Atlantic is warming up, enhancing prospects for a negative NAO this winter.

The Atlantic Multidecadal Oscillation is an index used for measuring water temperatures in the Atlantic. This AMO can be measured using a sea surface temperature chart like the one above. The chart above is the weekly SST anomaly. You can clearly see the warmer than normal temperatures across waters to the south of Greenland and in the Atlantic Canadian regions.

The NAO, or North Atlantic Oscillation, has a positive and negative state. In the positive, a high pressure forms over a portion of Greenland and blocks the atmospheric flow. This blockage releases cold air south into the US.

The AMO is related to the NAO in how the AMO affects the NAO's stage. Right now, the AMO is positive, providing warm waters to the north Atlantic. However, with these warm waters comes the increased likelihood of a negative NAO. A negative NAO can also be characterized by warm waters in the North Atlantic, and this correlation between the two may help explain the recent streak of negative NAO values.

So, the positive AMO appears to be on the East Coast's good side at the moment. Should this positive AMO continue into the winter, I have no doubt that the probability of a negative phase of the NAO would greatly increase.

It should be noted that last winter, the AMO was mainly neutral, explaining a part of the lack of a negative NAO.


Forecast Discussion for Monday, September 24

Today's Weather Hotspot: Rocky Mountains
A trio of systems will be producing a messy day today, with showers and storms making an organized appearance in the mountains. No significant severe weather is expected, however some small hail and brief heavy downpours are possible.

South Plains
An incoming warm front will produce a windy corridor across the region, particularly from Missouri into Texas. Isolated showers are also possible in the eastern part of the region. No severe weather is expected.

South Florida
Spotty showers and storms will be prevalent across southern Florida, especially later in the day. Brief heavy downpours and small hail are possible. No significant severe weather is expected.

Showers are possible across the Northeast, as cool air produces small lake effect showers. Additionally, a system offshore may ignite some moisture in the region.

North Plains
An incoming cold front will produce a cooler afternoon and evening today.


Sunday, September 23, 2012

Special Long Range Lookout: Sustained Cold In Long Range

This is a special edition of 'Long Range Lookout', being presented after the 12z GFS brings unseasonably cold air to much of the north and west parts of the nation.

As seen above, the 11-15 day average for 850mb temperature anomalies is very cold- as low as 14 degrees below normal. This actually puts the 850mb temperatures cold enough to produce snow- an occurrence being shown by the same 12z GFS.

As is to be expected, the long range verifies a very small part of the time, so one would usually take this with a grain of salt. However, looking at past trends of the last few runs of the GFS focused on 11-15 day 850mb temp anomalies, the model has been steadily trending colder with each run. What I would take away from this is that an enhanced appearance of cold weather is likely in the next couple of weeks, but the intensity is unknown.

Also of interest is the 11-15 day 500mb height anomalies. Notice the strong signs of a positive PNA, with a strong ridge in eastern Alaska and western Canada. However, the lack of a ridge near Greenland will result in an obstacle of being able to get the cold air east.

Considering there is a strong disturbance anomaly over south central Canada and central Canada, there should be at least one storm system that sweeps cold air east and into the Midwest and Mississippi Valley. The west-to-east motion of systems in the North Hemisphere means that this cold air will eventually move east into the eastern US, but the intensity of that cold air is in question.


BREAKING NEWS: TS Nadine Regenerates

Tropical Storm Nadine has regenerated in the far northeast Atlantic this morning.

TS Nadine is now what I like to refer to as a zombie tropical cyclone, as it has come back from the dead. However, this system won't be eating anyone's brains, whether in the US or Europe. Nadine is expected to move generally west, with wobbles north and south while on that path.

Nadine should not pose a threat to land in the next several days, but in the future, the Azores may want to keep an eye on the system should it make a wobble north and send some moisture that way.


Minnesota Low Temps Typical of October

Observed low temperatures from last night and tonight's forecasted lows are actually typical of October in Minnesota.

Statistics show that the average low temperature in September is 46.6 degrees (F) for the state of Minnesota. However, yesterday's actual lows provided by show that some locations reached as low as 29 degrees in the far northern part of the state. This beats the average low temperature of 35 degrees (F) in October across the state.

So? Why should you care? In weather, many times forecasters can use the persistence method of forecasting to their advantage. For example, if it was unusually warm for a couple of days, a forecaster may use the persistence method and say that it will remain warm. If it has been very rainy the last several hours and the skies look dark, the forecaster may say it will continue raining.

If we use the persistence method here, averaged out over a long period of time, it is possible that this indicates that the Northern US may be cooler than normal for the rest of fall. Now, this method has a lot of caveats and is not really used now that we have computer models. However, the possibility is there that this is an indication from Mother Nature on what is to come as far as the rest of Fall goes.


Summarizing Recent Winter-Related Posts

I know what I have been putting out in the last several days has been confusing, because there's so much information and there isn't really any good way to put it out there without some confusion coming along. So, this post is dedicated to clearing up any confusion related to any of the posts I've been putting out in the last week or two.

Q: What's with the El nino?
A: The El Nino is present in the waters, meaning the waters are warmer than normal. However, the atmosphere is failing to recognize that there is an El Nino- lower level winds are not favorable for El Nino conditions.

Q: I heard of an underwater cold pool a few days ago. What is that?
A: There is a large expanse of cooler than normal waters that developed under the El Nino- about 100-200 meters below the surface. This cold pool of water could take away the warmth of the El Nino, possibly killing it altogether.

Q: So is there going to be an El Nino for the winter?
A: As of now, we're not sure. I am seeing some signs pointing towards a lack of an El Nino this year. However, climate models are keeping the Nino (albeit weak) through the fall and winter. The waters are pretty murky, so to speak, and nothing is set in stone.

Q: Is your Official Winter Forecast still valid after all this talk about no El nino?
A: For the moment, yes. I will make any big changes in the Final Winter Forecast, which will come out in late October or early November.

Q: So what should I think about the upcoming winter?
A: In a summary, cool and wet for the East Coast, slightly dry for the Midwest and portions of the Ohio Valley. Wet for the South, warm for the Northern Plains.

If you have any more questions, don't hesitate to ask them in the comments below.


Forecast Discussion for Sunday, September 23

Today's Weather Hotspot: Central Plains
Despite the presence of a cool high pressure over much of the central US, some spotty showers appear possible for the region. Additionally, a close proximity of a frontal system to the high pressure will create a windy situation for the region today. Bundle up and don't get blown away!

Great Lakes
Lake effect showers will be falling in the wake of a cold front that brings cool autumnal air into much of the eastern part of the nation today. The most intensely-hit areas will be the western Great Lakes, where some heavier precipitation should be observed.

South Florida
A disturbance in the region will provide ignition for showers and a possible storm. No severe weather is expected.

Western Rocky Mountains
A disturbance in the region will provide the base for some liquid precipitation. No severe weather is anticipated.

An incoming disturbance will provide some showers just offshore the region. A little moisture may reach the coastal regions, but other than that, conditions should remain dry.


Saturday, September 22, 2012

Renegade Nadine On The Horizon?

The National Hurricane Center has put the remnants of Tropical Storm Nadine at 40%, as upper level winds are marginally favorable to reform the system.

It would be unusual to have this system reform, but not too uncommon overall. This would only continue to baffle the meteorological world, as this Atlantic hurricane season is already running above normal in an El Nino- something not usually seen.


Widespread Freeze Likely Tonight in Midwest, Plains

Light blue: Freeze Warning
Dark Blue: Frost Advisory
Widespread frosting and freezes are likely across much of the Midwest and Plains tonight, as the coldest air of the season moves into the country. Frost advisories stretch as far south as Springfield, Illinois, and a freeze warning is on the border with Canada, making this event span hundreds of miles.

Actions must be taken now to save plants and other vegetation in harms way of this first autumnal frost/freeze. Here are some tips to help your plants survive this night.

-Cover your plants with some cloth or an other covering. If the frost hits, the covering will take the brunt of the frozen dew, keeping the plant dry. NOTE: I have seen someone in my neighborhood put a styrofoam container over their plants with a brick on top. It seems to have worked well.

-If you absolutely adore your plants and feel like it's too early to see them off, you may even go so far as to put hand warmers around the plant in addition to covering them up. It isn't a bad idea if you want your plants to receive as little harm as possible.


Current LRC Pattern Showing Major Deviations Between Cycles

We are seeing some major deviations in the last Lezak Recurring Cycle (LRC) cycle. Let's take a look at what's happened in the last 40-50 days.

This is the observed 500mb chart on August 7th of this year. Here, we see a moderate ridge stretching from the Southwest into Western Canada, as well as a disturbance pressing south into the Great Lakes. Also being watched is a ridge of high pressure off of Atlantic Canada, and a strong disturbance near the Gulf of Alaska.

This day appeared to feature no major weather events, although some heavy precipitation was observed in the Southeast. The rest of the nation was pretty much dry.

Let's go forward to yesterday, September 21st.

Here, we see a much different, yet somewhat recognizable, pattern across the North American continent. Most notably is a very strong low pressure system being forced south into central Canada, and spreading an autumnal chill through the north central and north east regions of the US. This was not seen in the last cycle. Given, a much weaker version of this did appear on the August 7th chart, but the huge difference in strength is quite surprising.
Additionally, the ridge of high pressure I mentioned in the August 7th chart over western Canada is there, but is stronger. Also note that the same ridge pushed the disturbance previously centered over the Gulf of Alaska further west.
We still are seeing a ridge to the east of Atlantic Canada, signifying the presence of the same pattern, but that ridge is stronger than what was previously seen in early August.

We are entering fall, and this is the season when we begin to see the old LRC pattern die off and the new pattern emerge. Seeing as we just entered fall, these deviations I mentioned should become more intense and common, until the old pattern just disappears and a new pattern emerges.

Deviations are typical in every LRC cycle, but this particular comparison seems unusually anomalous from one date to the other. If I didn't know any better, I would begin to think we are starting to ease into that transition period between the new patterns. As always, time will tell, but this is another interesting development of the Lezak Recurring Cycle.


Long Range Lookout: Active North US Pattern To Continue

In this week's 'Long Range Lookout' segment, we'll examine what propsects the already-active fall season for the North US has for continuing into the next few weeks.

This is an ensemble forecast for the East Pacific Oscillation, or EPO. In a positive EPO, we see a strong trough centered over the Gulf of Alaska, with a ridge of high pressure extending west from Baja California and stretching across much of the Pacific. Additionally, a cold north US is a common trait of a negative EPO.

Recently, the EPO has been in a negative state, and this has been shown by the appearance of a strong trough over the Gulf of Alaska and cool temperatures across the northern US. This bodes well with typical negative EPO conditions. I will explain how this plays into a bigger pattern in a little bit.

We are also watching the Pacific-North American Pattern, or PNA pattern. In a positive state, the PNA creates a strong ridge over eastern Alaska and much of western Canada. This ridge enables storms to jump over the ridge, plummet down towards the Southwest, and follow the jet stream into the southern Plains. From there, the storms take a path that bodes well for high precipitation across the Midwest, Ohio Valley, and Great Lakes.

In the most recent week, we have had a positive PNA. This has been well reflected by the presence of a strong ridge in northwestern North America. Storm systems have been hitting the Ohio Valley and Midwest at a fair pace as well, illustrating the effects of the positive PNA.

Now, both of the above indices can (and did) mix together. The two combined to produce a ridge in the West, and a stormy pattern in the East, as illustrated below. This chart was from September 20th.

University at Albany
If the ensemble forecasts from above do verify, we could again see strong storm systems hitting the North US and bringing very cold air down to the region. This also includes the risk of some severe weather in the Northeast, as cold air moves in on warmer air brought up by warm fronts. This could also be a crucial sign of the incoming new Lezak Recurring Cycle. Every little change could mean something bigger later on.


Low GLAAM/GWO Proves Detrimental To El Nino

Background Information
GLAAM: An indice used to read whether an El Nino is present. High GLAAM Values indicate an El Nino, while negative GLAAM values show a La Nina.
GWO: Global Wind oscillation also used to determine the ENSO Phase. Respective phases marked on top and bottom of chart.

The GLAAM index remains at an unfavorable position to find the presence of an El Nino at this time, and has been unfavorable for quite some time, as the chart above shows. Not one day in the past several months has the GLAAM reached above zero, which would indicate an El Nino.

Only adding to the puzzle, the low GLAAM is basically saying 'There is no El Nino', while we clearly know that there is. There is a big difference between there being an El Nino in the waters, and an El Nino in the atmosphere. We have the first option at the moment. As seen above in the GLAAM, there is no El Nino found in the atmosphere. However, we all know that there really is an El Nino in the Equatorial Pacific waters. The problem is, the atmosphere is not acknowledging it.

The GWO (Global Wind Oscillation) has been hovering in neutral to negative territory for quite a while, indicting the lack of recognization is continuing to the El Nino, another step in the wrong direction. However, in recent weeks, the GWO has been moving slowly up, a more encouraging sign that the El Nino may finally be gaining recognization in the atmosphere.


Another Windy Day Greets Midwesterners

The first day of fall greets Midwesterners with a lot of wind, as the region is stuck between two cold fronts- one of which moved through yesterday, the other which has yet to move down through the region.

Latest observed sustained wind speeds shows as much as 20 MPH being reported near the Quad Cities area, with a windy 18 observed in Chicago at this hour. Small branches have been brought down across parts of the Chicagoland area, and this appears to be the case as well in eastern Iowa.

Forecasts from the WRF Model indicate that these winds will be dying down as the day progresses into the afternoon. This windy day comes just on the heels of a slightly windier day two days ago, when slightly larger tree branches had come down- some around the 1-2 inch threshold.


Forecast Discussion for Saturday, September 22

Today's Weather Hotspot: Northeast
A one-two punch of cold fronts will be moving towards the Northeast, creating a severe weather situation for the region. As cold air invades the warm air placed over the region, showers and thunderstorms (some possibly severe) will ignite. Considering this is the fall season, extreme severe weather is not too likely, but gusty thunderstorms are possible.

North Plains 
High pressure will move in behind a pair of cold fronts and place chilling temperatures over the area for the day Saturday.

Showers and storms are likely, especially in the southern region. As is typical with Florida thunderstorms, be aware of sudden pop-up cells that may form within minutes. No significant severe weather is expected.

Houston, Texas
High pressure will settle in over the area before an advancing cold front gets too close for comfort to the region. A gradually-clouding over sky is likely today.

Friday, September 21, 2012

El Nino Falling Apart; Underwater Cold Pool Growing

Latest analysis of underwater temperature anomalies in the Equatorial Pacific indicates that the El Nino is fading fast underwater.

Only two pools of warmer than normal waters exist across the Equatorial Pacific as of the latest analysis, yet another indication that this El Nino may not survive into the winter. Latest model guidance continues to trend weaker than what was being forecasted earlier, in terms of the El Nino.

Also of major interest is the presence of a very large pool of very cold temperature anomalies just about 200 meters under the waters of the El Nino. These cold anomalies have quickly strengthened in recent weeks, prompting extensive fears of the El Nino being destroyed by this. However, physics states that warm air rises and cold air sinks, and this is the same with water. Thus, the colder waters are encouraged to stay below the El Nino, but are not forced. The next several weeks will be crucial in terms of watching this cold pool do its thing.

I am tentatively keeping my prediction of a weak El Nino for the winter, but as we move through Fall, and the atmosphere continues to respond unfavorably to the El Nino, or if the cold pool grows further, the El Nino is seriously at risk for staying alive through winter.


Snow Radar Forecast Made September 21

Midwest, 1-2 Days
Precipitation will combine with below-freezing surface temperatures in the lower atmosphere to create an environment possibly favorable for some falling snowflakes. Very little, if any, accumulation is expected, making the intensity rating a '1'.

Midwest, 3-4 Days
Lake effect showers in the Upper Midwest will be occurring in sub-freezing temperatures in the 850mb layer. When that layer is below freezing, the surface can be as well. However, due to the tendency of unpredictability with lake effect showers, this gets a 'Medium' confidence rating.

Forecast was made September 21, 2012.

Forecast Discussion for Friday, September 21

Today's Weather Hotspot: Midwest
The Midwest will be under the gun today, as a mess of frontal systems and disturbances creates widespread precipitation in the region. The Upper Midwest looks to be dealing with a disturbance handling a cold front, which should ignite some spotty showers and maybe a rumble of thunder. A second disturbance based in NW Missouri should produce a wider expanse of heavier precipitation in southern Illinois, western Kentucky, and southeast Missouri. The movement of a disturbance into a region where warm air has been pulled north may produce some gusty thunderstorms.

Rocky Mountains
High pressure will rest over the area, bringing sunny skies, but cold nights. Lack of cloud cover means the heat gathered during the day is released back into space, further cooling down nighttime temperatures.

A frontal system will produce scattered showers and thunderstorms in the region. Residents should be aware of the threat of storms popping up in a matter of minutes.

A cold front intruding on a sector of warm air will produce some showers and thunderstorms, centered in western Pennsylvania and western New York. There does not look to be a big severe threat with this, but I will not rule out the gusty thunderstorm.

Spotty showers are possible, especially closest to shore, where a disturbance moving towards the region may pop up some scattered yet brief showers.

Thursday, September 20, 2012

Severe Weather Once Again Eyes Northeast for Saturday

Warm-Air sector: Air under the influence of a warm front.

The Storm Prediction Center has outlined a slight risk of severe weather for Saturday, September 22 in the Northeast. This comes as a cold front invades a warm-air sector and produces a risk of severe thunderstorms.

Model guidance is in fair agreement, with all models forecasting the cold front moving into the region on Saturday. All models being investigated this afternoon have timing issues, as far as placement of precipitation goes. Main concern is how strong models are progging this event to be. NAM is strongest, with heavy precipitation being marked over the outlined region above on Saturday evening. GFS and CMC are both more modest, and this is the way I prefer to go. GFS and CMC contain timing issues within themselves, as GFS is slightly faster than the NAM/CMC. Prefer to take a blend of CMC for timing and GFS for strength of storms. This would bring a moderate line of storms into the Northeast in the evening hours, specifically around the 6-8 PM ET timeframe.


Wednesday, September 19, 2012

Windy Enough For You?

Winds are sustained as high as 30 MPH across cities in the Midwest such as Chicago and Milwaukee today, as a strong warm front pulls warm air north into the region.

Wind gust forecasts from the GFS model at 10 PM (CT) this evening show gusts as high as 50 MPH over Lake Michigan, with over 40 MPH wind gusts possible on land, especially in the Western Great Lakes. The increase in wind will come as a cold front sweeps across the region and brings yet another cool down to the area.

Damage to trees, with branches being ripped off, has been reported. Are you in these chaotic winds?


Analogues For A Neutral-ENSO, Negative PDO Winter

As the atmosphere continues its refusal to recognize the presence of an El Nino, and sudden cooling of waters below the El Nino erupts, it has come time to think about what would happen in a neutral ENSO winter, because as of now, hope for El Nino fades with every day the atmosphere does not recognize its presence.

These are years hand-picked by me to ensure as much accuracy as possible in these analogs. These 4 years contained both a neutral ENSO winter, as well as a negative PDO comparable to what that we are in now.

The analogs I have chosen have indicated that a cool winter would most likely arise from a neutral-ENSO/negative PDO situation, with anomalies of -1 to -3 being found across the Plains and Midwest regions. The East Coast contains neutral temperature anomalies, with maybe a bit of warmer than normal temperatures being found in upper New England. As for precipitation, a very wet scenario encompassed the Southeast, Gulf Coast, and East Coast, where over 3 inches above normal precipitation could be found. Some wetter conditions also prevailed in the Midwest, Ohio Valley, and parts of the Northern Plains.

One can find the La Nina side of this analogue choice in the temperatures, with a general cool down over the Northern half of the nation. A somewhat El Nino-y scenario is spotted in the South and East, with very wet conditions in those areas. Should we continue to see a strengthening of cooler than normal water anomalies below the El Nino, these 4 years may hold the key to winter. Of course, this will depend on how the 'fake' El Nino evolves over the next several weeks.


Tuesday, September 18, 2012

Cool Underwater Anomalies Threaten El Nino's Existence

Latest underwater anomalies from the TAO/TRITON agency suggest a building of cooler than normal waters below the surface. This comes as the atmosphere does not react favorably in the presence of an El Nino.

Waters as cool as 2 degrees below normal are being measured approximately 200 meters below the surface, outperforming that of the El Nino, which is being clocked at 1 degree above normal. Common sense says that such an abundance of cool water is suggesting something is happening, whether it is recognized or not. At the moment, I have a fine time believing that these colder waters will rise to the surface and overtake the El Nino to make for a neutral-ENSO winter. This body of cooler waters has been strengthening over the past while, as the El Nino actually takes it down a notch.

For those wondering, if this were a La Nina (NOT saying it is), this would be more east based, borderline central based. However, I am not nearly defining this as a La Nina. It is what it is: a cool body of water below a warm body of water.

This is one of the tricky parts of forecasting: Do you judge a book by its cover, or do you look deeper into what's really going on? I, in an attempt to give you the best information, believe that these cooler waters are weakening the El Nino. I do not anticipate an El Nino to be around by the time January rolls around. I base this on an unfavorable atmospheric response thus far, as well as this new cold body of water that, should it be on the surface, would be classified as a strong La Nina.


Record Low Arctic Ice May Play Crucial Role In Atmospheric Blocking Come Winter

A record low amount of ice in the Arctic could play a big role in how atmospheric blocking may evolve in the upcoming winter.

At the latest observation, ice in the Arctic was down to 3.5 million kilometers(squared). That seems like a lot, and you bet it is. But, when you see that the average for this time of year is hovering around the 5-6 million square kilometer mark, you can see that this is pretty unusual.

The lack of sea ice, in a cause-effect relationship, typically reduces the amount of cold air in the Arctic. The less cold air there is in the Arctic, especially in wintertime, the more negative the Arctic Oscillation tends to be. The Arctic Oscillation favors cold weather in the US when in the negative phase. Now, if the cold air has fled south into our neck of the woods, this means that there is a ridge of high pressure in the Arctic. Should this ridge happen to be close to Greenland, we could also see the North Atlantic Oscillation (NAO) drop into negative territory. This is plausible, considering the two are closely related. In the event the NAO and AO both go into negative territory, the East Coast is in a much better position for big Nor'easters to hit.

This has been proven to possibly be correct, as the NAO has had an unusually prolonged stage of negative values in the past summer, even to this day. The forecasts for the NAO are also still looking fairly negative, further giving life into the possibility that the lack of ice is to blame. Unless we see a rapid build-up of Arctic ice in the next few months, an abundance of cold air in our neck of the woods could very well play out. This, of course, depends on if the other indices in the atmosphere agree.


Monday, September 17, 2012

1 Million Page Views Reached

The Weather Centre has broken 1 million page views as of today, September 17, 2012, after 29 months of publishing my thoughts on the weather.

I could never have dreamed of getting this far, and want to THANK YOU for supporting this blog for so many months.

Here's to many more years of weather to come!


Sunday, September 16, 2012

Hurricane Season Running Above Normal; Atlantic Not Obeying El Nino

The 2012 Atlantic Hurricane Season is entering its second half, and already we are above normal for total named storms.

The average number of named storms averages out to roughly 11 storms, encompassing tropical storms, hurricanes, and major hurricanes. The number of hurricanes overall stands at 6, while annually, major hurricanes strike about 2 times. This year, statistics show that we have had 15 total storms and 14 named storms (there was one unnamed tropical depression). It is only September, and we have passed the 1966-2009 annual total storm count. The number of hurricanes we have had this year is also above normal, with 8 recorded hurricanes thus far. It has been proven to be an active season. But not many expected this. In a way, this could be the Renegade Hurricane Season of 2012. But what made this season so unexpected?

The hot topic of El Nino (excuse the pun) is to blame. In an El Nino, which is defined as the warming of waters in the Equatorial Pacific Ocean, atmospheric winds in the Atlantic turn unfavorable for tropical cyclone development. The lowest number of named storms in the Atlantic actually result from an El Nino. However, as was explained above, this year is not the case. This could very well be the result of the lack of recognition of the El Nino, as was explained in a previous post.

Because this season has been so odd, the confidence of a long range forecast on the rest of the hurricane season is drastically reduced. However, if I were to take an estimate on what may happen, I have a feeling that this unusual activity will continue. Areas of possible development in the Gulf of Mexico and Caribbean at the time of publishing (uncommon for September tropical development) points to this as well.


1 Hour Winter Q-and-A on September 22 at 12:00 PM CT

Keeping with last year, I will be doing an hour-long question-and-answer session on the upcoming winter next Saturday, September 22, at 12:00 PM CT.

This is your opportunity to ask any and all questions relating to the upcoming winter!


'More Of The Same' Pattern To Continue

One of the best methods of forecasting is to use the persistence method, where you forecast based on past days. For instance, if it were hot for 3 days, you might assume it will be hot again tomorrow. If it were rainy for a few hours and the skies looked dark still, you might think it will keep raining. That rule is being applied to the next couple of weeks.

Currently, there is a big ridge in the West, and a very active storm track in the East. Helping this to happen is a positive PNA and negative EPO pattern. Below are their forecasts for the next 15 days.

Both indices are forecasted by the NCEP (Agency who manages the GFS, NAM, etc.), and the ESRL/PSD (the agency that is more on the technical side of models and forecasting.

Both agencies have the EPO heading negative in association with the ridge forming over the West. Considering it will be a strong ridge, I think the NCEP is correct in its assumption of the PNA over the next 15 days. As you can see, the PNA is much more positive with the NCEP than the ESRL/PSD, and I believe this is the correct way to go, based on how strong the models are with ridging in the West and troughing in the East.

Now that we are heading into Fall, such strong storms should become more common. I do not dispute that this could easily happen again in winter, as there has been much more persistent ridging in the upper latitudes than last year. It will be quite interesting to see if this pattern can get established for the fall and possibly winter.