Wednesday, May 16, 2012

'Super Storm' on FIM Has Past Relations with LRC

EDIT at 8:55 PM CDT (5/16): Severe weather report graphic was replaced.
The latest FIM model is blowing up a storm system in the eastern Rockies on the 25th to as low as 982 millibars, or slightly lower. This is definitely the strongest system I have seen in a while. (Granted, I don't exactly check out all the long range models on a daily basis)

This has, in fact, happened before. Let's take a look. Here is what happened in the 500mb level on Saturday, April 14.

We can see a strong storm system digging deep into the Southwest, with another area of lower pressures located just north of Montana. The system in the Southwest does appear to be very intense, judging by the depression in the pressure lines running across the graph. Of interest is also the ridge of high pressure in the eastern US, and the storm system offshore the Mid Atlantic, characterized by the depression of the pressure lines.

Severe weather reports do indicate that a tornado outbreak did occur (or a few cells with long tornadoes), and this could indeed happen again. The details will have to be worked out at a later date, however.
Now, let's take a look to what the FIM is showing going into the 27th of May.

The FIM is showing a deep low pressure system moving into the Southwest as well, with a storm system (potentially tropical) offshore the Southeast and a strong ridge in the East. Does this look familiar? It should. Now, some details still have to be sorted out, but this does appear to match up with the Lezak Recurring Cycle time of about 45-50 days for each cycle. That said, a severe weather event should be expected in the late May timeframe if the LRC holds true.

Props to the AccuWeather Forums for their extensive knowledge on the subject.

Andrew

Tropical Storm Aletta To Quickly Weaken in Midst of Dry Jet Stream

This image is from the ADT agency, or Advanced Dvorak Technique, from the CIMSS Tropical Cyclone tracking page. In the red and blue boxes, we have the center of the system. Notice the convection still ongoing around the front flank of the system. These storms should quickly dissipate as they approach and are sucked into the jet stream. The track continus to call for a general west northwestward direction before a turn to the north and eventually northeast as the jet stream takes hold.

Andrew

Tuesday, May 15, 2012

Tropical Storm Aletta Shifts Out to Sea; New Development Possible

Tropical Storm Aletta is currently moving westward in the middle of the Pacific Ocean, far west of Mexico, pretty much in the middle of nowhere. Winds are sustained at a fair 45 MPH, making for a moderately weak tropical storm. The system is expected to fade out as the westward movement continues, with an eventual turn to the north, before the system becomes post-tropical.

And of course, because the East Pacific needs more storms than the Atlantic (which should be achievable with the now-dead La Nina), we have an area of potential development over the next several days. While it is at 10% now, the National Hurricane Center has indicated that development appears possible over the next several days.

And lastly, we have an area of weak showers drifting around in the far northeast Atlantic. Yes, there is a circulation judging by visible clouds, but there is also a patch of tightly wrapped showers within the system. Needless to say, there is a 0% chance for development as it isn't even classified as an invest at this point.

Andrew

Severe Weather Targets Chicago, Milwaukee Today

There is a slight risk of severe thunderstorms today from northern Illinois into southern Wisconsin and southwest Michigan. Extreme northwest Indiana and eastern Iowa are also included in this risk.

Current surface analysis indicates a cold front will be sweeping south and east into the area highlighted, bringing what the Storm Prediction Center calls 'supercells and/or severe multicell line segments' to the region.

Considering the area highlighted is within warm temperatures but not so high humidities, these storms should not be incredibly rainy, so flash flooding is not anticipated in most areas. However, heavy rainfall in an area cannot be ruled out.
When the SPC is talking about these 'severe multicell line segments', they are discussing bowing segments of storms.

At around 6:00 PM CDT this afternoon, the SPC's WRF-NMM model is projecting that a line of strong storms will ignite in the region and likely produce some severe activity in the region.

The same WRF-NMM run off a different machine tells that the storms should be based farther west. Considering that the first image is from what I consider the 'operational' forecast, and it seems to be in line with the SPC, I will go with that solution.

Andrew

Monday, May 14, 2012

Short Term Tropical Outlook

Made May 14, 2012
This is a short term tropical outlook from The Weather Centre. This is meant as a guidance product and is not to be used in replacement of official forecasts from the National Hurricane Center (NHC).

Central America
For days, the FIM model has been projecting a tropical system to impact Cuba, Florida and possibly hitting the southern portions of the East Coast, although that has been in debate. What I have been seeing is what appears to be the monsoonal trough stationed in Central America at this time. Because convergence of moisture and winds are associated along the trough line, it is only a matter of time before something happens. Seeing as temperatures are above the necessary 80 degrees (F) in the red circle, and there will be converging winds and moisture in the area, showers and thunderstorms may very well propagate east into the Atlantic and fire up a tropical system, as is being projected now in the late May timeframe.

Gulf of Mexico
Temperatures in the area have surpassed 80 degrees (F) in the southern half of the region, an essential ingredient for tropical activity. Now, the monsoonal trough is not near the Gulf of Mexico, so there is not as much of a force to bring massive amounts of warm air into the atmosphere to make some thunderstorms. However, this could be the focal point for systems later on, and it will have to be watched.

Open Atlantic Waters
A ridge of high pressure appears to be extending into the region highlighted, and this would indeed discourage any storms from forming in the area, but also enhancing the potential for landfalling systems.