Thursday, April 21, 2011

April 21: Tornado Warning- Southeast Terrell County, TX



...A TORNADO WARNING REMAINS IN EFFECT UNTIL 830 PM CDT FOR EAST 
SOUTHEASTERN TERRELL COUNTY... 
 
AT 807 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO 
DETECT A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO OVER 
SOUTHEASTERN TERRELL COUNTY...OR ABOUT 18 MILES EAST OF 
DRYDEN...MOVING EAST AT 20 MPH.

April 21: Tornado Warning- Fisher County, TX


* TORNADO WARNING FOR...
  SOUTHEASTERN FISHER COUNTY IN WEST CENTRAL TEXAS...

* UNTIL 745 PM CDT

* AT 709 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO WAS 3 MILES WEST OF LONGWORTH...OR 12 MILES NORTH OF
  SWEETWATER...MOVING EAST AT 20 MPH.

  IN ADDITION TO DANGEROUS TORNADIC WINDS...OTHER HAZARDS INCLUDE...
  DAMAGING STRAIGHT LINE WINDS IN EXCESS OF 60 MPH.
  POTENTIALLY DEADLY LIGHTNING.

*THE TORNADO WILL REMAIN OVER MAINLY RURAL AREAS OF...
  SOUTHEASTERN FISHER COUNTY.

April 21: Tornado Warning- Central Terrell county, TX


* TORNADO WARNING FOR...
  CENTRAL TERRELL COUNTY IN SOUTHWEST TEXAS...

* UNTIL 745 PM CDT

* AT 639 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 7 MILES EAST OF
  SANDERSON...MOVING SOUTHEAST AT 25 MPH.

* THE TORNADO WILL AFFECT THE FOLLOWING LOCATIONS...
  RURAL LOCATIONS NORTH OF U.S. HIGHWAY 90 BETWEEN SANDERSON
  AND DRYDEN...
  DRYDEN...

April 24-27 Outbreak: Affected Areas (April 21)

3 days away, the HPC is predicting the cold front to begin storms to develop.
Below is the surface analysis forecast
A triple point is especially worrying. Below is the HPC gridded forecast providing a more accurate description of the system.
At 7pm CDT, a large area of severe storms will erupt. They should be in the area delineated in the area above.
Next will be the forecast for 5 days out.
Here we see a much more potent severe weather squall line. This also has more confidence, as the forecasters gave the area in dark red a 'likely' chance of convection.
The Weather Centre will keep monitoring the storms.

Rising Concern over potentially historic tornado outbreak April 24-27

There is rapidly rising concern over a potentially historic tornado outbreak in the Plains, Midwest, Great Lakes and Ohio Valley.
The SPC has issued a risk area for 4 days out.
There is a triple point forecast in the graph mentioned.
A triple point is when a cold front and warm front meet together to form an occluded front, thus the term 'triple point'.
If supercells form in thise areas, it is quite possible they will be tornadic.
When a front moves through, it is two air masses colliding. That makes a lot of wind on the surface.
With a triple point, the weather goes nuts and is pretty much unpredictable.

HOWEVER- There are changes from the last forecast.
-The low is MUCH weaker than the last forecast.

That means the storms could possibly be a lot weaker.
However, the models are very unprepared and bad at handling this storm.
We will update this as necessary.

Extensive Flooding Possible April 21-26

There is a high potential for extensive flooding in the midsection of the US.
Below is forecasted rainfall.
Yes, that is 11 inches in extreme northwest Arkansas.
Be very careful if you live in an area that has gotten a lot of rain recently and is forecast to again in this image.