Friday, September 30, 2011

18z GFS displays concerning image for Northeast

The Long-Range GFS is painting a concerning picture for the Northeast. What we have here appears (keyword is appears) to be a tropical system- the tropical system that is currently Tropical Storm Philippe. This is hour 288 on the GFS, so it can be considered unreliable, but I am watching this one more closely than I would with other systems because: A) The system responsible for this potential landfall (TS Philippe) is already stirring in the ocean, thus the models are full of data. B) My gut instinct is telling me this might happen. I'm not saying you should trust my gut, but it's something to think about.
For those concerned, here's a real-time image of Philippe.

Ophelia Heads Out to Sea with Final Burst of Strength

The Category 3 Hurricane we know as Ophelia is on a track that will whisk her away out to sea. I was surprised to find Ophelia at Category 3, and makes me think this is her final farewell. All guidance indicates she will be going out to sea, but this is certainly one of the more impressive eye formations I have seen this hurricane season.
Forecast Guidance

ECMWF model showing Ominous Potential Tropical System Near Cuba at Hour 240

The ECMWF model is showing an ominous system near Cuba at hour 240 that may be a tropical system. This is the first time the ECMWF is shedding light on the possibility, but if it does form, the ECMWF indicates wind shear will be high as per the high pressure system in the Mid-Atlantic. Wind shear is good for tropical systems, but too much of it can literally tear the system apart. At the moment, this 12z run of the ECMWF indicates a lot of wind shear to the north of this projected system, which would hinder its development. This is the only model to be showing it, but we will keep up to date on it nonetheless.

Cool Air Mass will succumb to Warm Air in the next week

GFS Ensemble members are indicating that the cool air mass currently in place will be pushed away into the Atlantic, and a warm air mass will take its place, giving cities like Chicago, Milwaukee 70's and sun after a week of clouds and rain. This warm air mass will be around for about 5 days before a front comes through the region (possibly with thunderstorms) and brings temperatures back down again.

SnowCAST- September 29, 2011 (Valid September 31, 2011)

We have been watching the potential of snow for the last several days in the Northeast, and it now appears likely there will be some snow, possibly accumulating, in the Northeast region. If there is to be any accumulation, totals will be at or below 2 inches, with the best chance for accumulation in the West Virginia area. The region outlined in lighter blue is where flurries are possible, but where accumulation is unlikely or will be below .5 inches.
Any accumulation that does occur will melt quickly.
Next 5 days to get wet and wild in the Northeast:

West Virginia could see 2 inches of snow this weekend

Portions of West Virginia may get in on up to 2 inches of snow this upcoming weekend. It is anticipated this snow will melt quickly after it falls. It is anticipated to melt on Sunday, and the snow will likely be slushy.

Thursday, September 29, 2011

National Wind Speed Gusts/Sustained Winds for Tonight

Pre-Reading Notes: This is not a briefing, but an image forecast.
All speeds are in knots. Click here for a knot to mph converter.

Wind Gusts (knots)

Sustained Winds (Knots)

September 29- Place to Be: Mountain Home, Arkansas

September 29, 2011's Place to Be is Mountain Home, Arkansas.

Mountain Home

Snow still Possible for Pennsylvania, New York this Saturday

Pre-Reading Notes: 540 line is the line separating rain and snow. North of 540 line- snow. South- rain.

The GFS continues to show the potential for snowflakes to fly in New York, Pennsylvania this Saturday as a cold blast shoots into the NE. In terms of snowfall accumulation, there will be potential for small amounts to accumulate in portions of the areas at risk for snow. Below is the 6z forecast 120 hour snowfall from the GFS for the areas in question.
The largest amount possible will probably be 2 inches, but that will quickly melt if it even falls.  We will continue to watch this unfold, and provide constant updates if needed.

'Windy City' Chicago to live up to its name today

Pre-Reading Notes: All images are in KNOTS. Click here to convert Knots to MPH.
Forecast Surface Wind Gusts
The Windy City will get a lot windier over the next several hours as a cold front will drop from Minnesota through Chicago, IL. After it does, sharp winds will batter Chicago, Milwaukee WI, Madison WI, Gary IN all at once. The image we have put above is of projected surface wind gusts (which appear very plausible to me at this point in time). Chicago is forecast to have its sustained winds at 25 MPH for 17 hours. It is possible that many areas could see widespread minor damage, such as small limbs of trees down, or possibly the occasional roof shingle. As stated before, sustained winds are expected to be in the 20's for a while. Here's the projected sustained wind speed for the same time frame as the image above.
It appears only areas close to the lakes (i.e. Chicago) will get the very windy sustained conditions. That doesn't spare the more inland areas from wind gusts up to 40 knots, which is actually 54 MPH.. It appears widespread areas of 40-45 MPH winds are possible as referenced in the first image.
We will keep you up to date on the unfolding situation, and will be back in a couple hours with the new 12z model run.

Training Storms leave varying amounts of rain in South Louisiana

Using our specialized radar system, we have identified storm totals for last night's training severe thunderstorms. Training means one after another, so it is like a train. A very long train. Training storms are very prone to cause flooding, and are my choice for the best type of storm able to produce flash flooding.
Anyway, we checked two radar sites that are within the hardest hit area's range. The hardest hit area was Maringouin, LA. However, the input from the two different radar sites differed. We ended up deciding to show the one that seemed the closest to the radar itself, which would be where the most accurate information would be.
We have labeled them for your convenience. So this is from a radar centered in the Lake Charles, LA area. The the other radar site that we looked at was a bit to the northwest of New Orleans. The tricky thing is that this radar had an entirely different scale. Keep in mind the exact same scenario was occurring within these two NWS Offices that run the radars. The specialized radar system The Weather Centre uses collects raw data from the radar- direct from the source, so to say. Because there is no flash flood warning (or flood warning for that matter), we don't know what happened to the 6-10 inches of rainfall. (6 inches was the maximum total estimated for the other radar site.) There was a flaw flood warning at one point. Maybe the radars had an accident (highly unlikely since two separate radars both estimated more than 5 inches of rain fell). We may never know as there appear to be no visible spotter reports.

Wednesday, September 28, 2011

Doppler Radar Estimates 8.0 Inches of Rain in Maringouin, Louisiana as Training Storms Continue

Training thunderstorms are taking their toll on the New Orleans, Baton Rouge region this evening as more and more of them ignite. We are seeing unbelievable reports of 8 inches on our specialized radar system, but the National Weather Service storm total estimates are above 10 inches. We are in disbelief as of why no flash flood warnings are in effect.
Here's our specialized radar Doppler estimates of storm total rainfall so far:
Dark Pink: 8 inches
Lighter Pink: 6 inches
Pale-ish Red: 5 inches
Red: 4 inches
Maroon: 3.5 inches
Orange: 3 inches
Lighter Orange: 2.5 inches
Lightest Orange: 2 inches
Yellow: 1.5 inches
Anything Green- Below 1.5 inches

This is as of when these storms started this afternoon. The images coming from infrared satellite imagery are quite impressive:
You can definitely identify the severe storms in this system. These storms are moving in a southeast direction and will die off as they go offshore. We anticipate these storms to continue forming through at least the 8:30 PM CDT time frame, but with faulty NWS forecasts, we don't have a good direction of what will happen later on.

Lake Michigan, Superior to get windy in next few days

The GFS is predicting Lakes Michigan and Superior to get quite windy over the next several days as a system moves through. The system will be quite strong, with a central pressure of 994 millibars- very low for a system on land. Boaters should take caution when this system moves through this Friday . You can check out the forecast low pressure system below.
Forecast Mean Central Pressure Nationwide this Friday

Training, Severe Thunderstorms Erupting in New Orleans Area This Evening

Severe thunderstorms are erupting in the New Orleans area this evening as a wobbling front initiates the storms in the region. Satellite imagery is showing a very impressive view of the storms, and we have detected cloud tops to 45 kilo feet, or 45,000 feet.
Latest Satellite imagery over New Orleans, LA
Radar-Detected Cloud Tops (Darkest red is 45,000 feet- each color  shade below that goes down 5,000 feet)

Tuesday, September 27, 2011

Long-Range GFS Gives Snow to Wisconsin, Iowa

The latest available Long Range GFS is showing a system giving snow to Wisconsin, Iowa and Missouri. Wisconsin may get up to 4 inches of snow out of this. If it verified. However, since it is the Long Range GFS, we don't get too excited about it. We will track this, but not carefully.

Long-Range GFS Predicts 'Megastorm' over Minnesota similar to last year

Pre Reading notes: This image is out of date and is being shown only as a cool photo.

Yesterday, the Long-Range GFS put up an image showing the possibility of another 'Megastorm' originating over the Minnesota area, not unlike the superstorm last year. Here's the outdated image from hour 384 of the GFS.

Pennsylvania, New York could get in on some Snow by Sunday

There is potential for some snow flakes to begin flying in parts of West New York and Pennsylvania. The image below shows projected surface precipitation on Saturday at 8 AM EDT. The blue dashed line is what's known as the 540 line- the line typically separating rain and snow areas. Places south of the 540 line get rain, regions above the 540 get snow. Below is the image for Saturday at 8 AM EDT.

If you look closely, you can see the blue dashed line sagging southward and encompassing portions of New York and Pennsylvania. That said, there is indeed a potential for snow. The question is- how much?
Many of you probably aren't ready for winter (mentally or physically), but the good thing is that any snow that happens to fall will melt, as that 540 line will fly back north into Canada. Here's the details as of now:

-The models are not forecasting any snow to fall
-There is potential, but it is low
-Flakes flying in the air if this turns out is a possibility
-Accumulation above .1 inches is unlikely for now.
Threat of heave rain somewhat low- threat still present, though.
Still more rain expected this afternoon in the ohio valley

Monday, September 26, 2011


We will be focusing our attention on the Weather Models page in upcoming days.

Portions of Northeast in for a Soaker Tonight

Pennsylvania, Ohio and similar states will be in the target range for a very wet night in accordance with a nearly stationary low pressure system in the Illinois region. As a cold front spun up showers and storms this morning, the front will continue moving to the northeast. Even right now, strong showers and storms are in the area designated as a threat for potentially flooding rainfall. Here's the forecast QPF (rainfall totals) for the next several hours in Figure 1, as well as the Heavy Rainfall Threat graphic for the same time frame in Figure 2.

Figure 1- Forecast rainfall for the next several hours

Figure 2- Heavy Rainfall threat graphic

Ohio/pennsylvaia watch out in next 2 days for flooding risk. Forecast rain today, tomorrow
We are watching the potential for heavy rainfall as well in the next coming days.
The low in illinois continues to produce heavy showers and storms in NW IL. The showers may dissipate later today, and we will watch for that.

Low Pressure System in Illinois makes Cold Front in Kentucky (Early Morning Overview)

A low pressure system stationed over Illinois/Iowa will continue to produce showers and embedded thunderstorms in the center of the low as well as a front moving east into the Eastern Seaboard. Below is a current surface analysis map of the storm and cold front.
The low will wobble to the west and east in the next few days before finally being pushed off to the east, providing a day or two of partly sunny conditions over the Midwest/Great Lakes before another low is forecast to move in to the same area. There is a lot of rain occurring in association with this system right now, and below is current radar imagery of the US.
Moderate rain is falling in Wisconsin, Illinois into Ohio, Kentucky and Tennessee, with some more scattered showers in between. The cold front has even prompted a tornado watch to be issued for East Kentucky as well as South Ohio. Below is the region outlined for this watch.
This watch is valid until 12:00 PM CDT/1:00 PM EDT. It appear this watch was issued due to the potential strengthening of this front moving through. While the only immediate 'danger' looks to be a small line of embedded cells, the SPC believes it will strengthen. There are embedded mesocyclones, or spinning in the clouds, as well as high values of SRH (spinning in the atmosphere). Added forcing upwards of air (what the name says it is) increases the overall risk of tornadoes.

Saturday, September 24, 2011

1st Official 2011-2012 Winter Forecast

See the video briefing here:
Mentioned by 8NewsWeather in Richmond, Virginia

See updated Midwest Snowfall Map Here: ***UPDATED*** 2011-2012 Winter Snowfall Map for Midwest
See the Official 2011-2012 Winter Storm Track Map and Discussion Here:  NEW: ***OFFICIAL 2011-2012 Winter Storm Track***

Hello everyone, this is the first official 2011-2012 Winter Forecast produced by The Weather Centre. We have decided that this will be an official forecast rather than a 3rd preliminary forecast, as we are investing a higher amount of confidence in this forecast than we would in a preliminary forecast.
Let's take a look at the newly-declared La Nina this year.
The La Nina is currently East-Based, meaning the lowest temperatures are sourced from the eastern regions of the ENSO areas. To know where the ENSO area is, just look along that horizontal line in the images above- that is within all the Nino regions. Anyways, looking at the SST (Sea surface temperatures), it is very clear a La Nina is in effect on the far eastern side of the ENSO region, with anomalies below -.5 degrees, which is the threshold for a La Nina. The CPC does expect this La Nina to continue and strengthen onwards as we continue through this year.
You might be wondering what all this talk about East Based La Nina is. Below are the temperature effects from West and East Based La Ninas.
The East-Based Nina favors a cooler nation, while West Based La Ninas typically torch the East Coast westwards through into the Plains. Right now, I am expecting this East Based La Nina either to stay where it is, or more likely, spread slightly westward into the center of the ENSO area.
The CPC does make forecasts as well, and they are something we analyzed closely while looking at this forecast. Below is the December-January-February (DJF) forecast for precipitation, then temperatures.

One thing to base anomalies off of is historical information from past Nina's. Below is the raw data for a typical La Nina in terms of temperature and precipitation.

Something else we can forecast for is the NAO, or North Atlantic Oscillation index.
The NAO is basically associated with a permanent low pressure system over Iceland (Icelandic Low) and permanent high pressure system over the Azores (Azores High). These two vary in daily and monthly etc. strengths, and that variation is called the NAO. Below you can see an example of the variations in pressure.

 When the pressure difference (because high pressure has higher pressure and low pressure has lower pressure) is strong, that is a +NAO index. When that difference is lower, that period is called a -NAO index. Below is a graph depicting past NAO index readings.
You can see how the NAO went negative during practically the whole 2010-2011 winter. Recently, the NAO has also been down. When the NAO is negative, it leads to heat waves across the US. You can take a more short-range past look at the NAO below.

All that considered, we can produce a very good forecast for the US. We present to you the 2011-2012 Winter Forecast by The Weather Centre.

 The Ice Threat for this year is in similar areas as to last year, but with a more pronounced threat out west with the potential for a warm winter start across the nation's midsection.

We strongly believe the North US will be very cold, with much of the north half of the US cooler than normal as well. This La Nina will keep the Southern US warm, and, yes, dry. Things will only get worse throughout this winter for the South. The entire Midwest/Northeast/Upper Midwest will get in on above average precipitation. While we cannot pinpoint if all of that will be snow, we are taking the chance that the majority will be snow. The West Coast may have to deal with another wet winter, but we are not entirely sure on that prospect. Portions of the western North Plains will have potential for above average snowfall forecast. This is based on the prospect for clippers this year. We anticipate the North Plains to receive quite a bit of snowfall from these clippers. If the worst case scenario pans out, you will need a new (and bigger) snowblower this winter in the North Plains. Lake Michigan is warm. You know what that means- lake effect snow. Undoubtedly, there will be very heavy amounts of lake effect snow for Michigan, Indiana, and probably Chicago, IL. 
There is something we have to discuss- the Southeast Ridge (SE Ridge). The SE Ridge is an area of high pressure that forms over the Southeast. This ridge of high pressure directs low pressure systems northward towards the Ohio Valley and Great Lakes/Midwest region, in turn giving those places snow. An example of this is the 2011 Feb. 1-3 Groundhog Day Blizzard. This unusually strong storm fired from the South US north and demolished Chicago and places nearby. There is a consensus that this SE Ridge will be stronger than last winter. This would mean the storms having a slightly higher likelihood of going north than south. I do see a potential for 12'' snowfalls (notice the plural) across the Midwest/Ohio Valley/Great Lakes, but I hesitantly say no to another Groundhog Day Blizzard. That was a once in over 20 years storm for the Midwest. This SE Ridge's strength may affect the Northeast's traditional 'Nor Easters', but there will still be the heavy snow, ice and rain for them too. 
Bottom line- this winter will be wild across the Northern tier of the United States. From Chicago to New York, it will get messy. If you haven't already, buy an extra shovel or two for this winter, ESPECIALLY if you live in a lake effect snow-prone area.

WRF Predicts Strong Storms in South Illinois

Valid at 5 am tomorrow morning, the WRF model is predicting that Southern Illinois will get socked with a line of strong, training thunderstorms associated with a low pressure system over the region. It looks like this image is the peak point of the storms, after this they spread out into moderate showers over a larger area. This image indices the threat of flooding, as it appears possible the storms may be training. In Figure 1, check out the 12 hour precipitation.
Figure 1

1st Official 2011-2012 Winter Forecast comes out in just over 2 hours.

The 1st Official 2011-2012 Winter Forecast will be released in just over 2 hours.
Make sure you're here when it's released!

Fantasy-Land CFS Model Shows US Taking Quite a Cold Hit

This is an image of the CFS model for 1020 hours out (meaning it won't happen, or theres a microscopic chance it will, thus the post name 'Fantasy-Land') for temperatures across the US. These temperatures are calculated in Celsius, so with the -21 Celsius reading on the IA/IL/WI border comes a -5.8 Fahrenheit temperature reading.
Again, take this with the smallest grain of sale- it's just something interesting I wanted to share. 

Friday, September 23, 2011

Winter is Coming... Series- What is a clipper snowfall system? Q/A

Average Clipper Track
Q: What is a 'clipper'?
A: Called an Alberta Clipper in its formal name, the clipper is a snowfall system that drops from Alberta, Canada and affects the Upper Midwest. It is a fast-moving low pressure system that can bring much colder temperatures behind its passage. Due to the fast movement, snowfall amounts are typically low, but have been known to go above 6 inches.

Q: How much snowfall can typically be expected from a clipper?
A: Usually 1-3 inches of snow due to the moisture-starved nature and fast movement of the storm. A stronger clipper can put down 6 inches or more, but that is more infrequent.

Q: How much can temperatures plummet after the passage of a clipper?
A: It is typical for temperatures to freefall 30 degrees right after the passage, accompanied by nasty winds.

First day of Fall!

Today is the official first day of Fall, which started just after 4:00 AM CDT.
Temperatures will fall and days will get shorter. Winter will be coming around the corner...

1st Official 2011-2012 Winter Forecast comes out tomorrow!

The 1st edition of the Official 2011-2012 Winter Forecast comes out tomorrow at 12:00 PM CDT.

Today's Forecast- September 23, 2011

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