Daily Archives: December 4, 2012

Severe Hail Storm approaching Raymondville; Heading towards Harlingen in the Valley

A severe thunderstorm capable of producing large hail has developed in higher instability values in the Valley. This storm is located just west of Raymondsville and is moving south/southeast. Current estimations keep the main hail core just west of downtown Harlingen, but we’ll watch the trends over the coming 20 minutes. This storm is moving at 20 MPH and is producing copious amounts of lightning. Here is the radar image along with the severe thunderstorm warning.

THE NATIONAL WEATHER SERVICE IN BROWNSVILLE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR…
NORTHWESTERN CAMERON COUNTY IN DEEP SOUTH TEXAS.
WESTERN WILLACY COUNTY IN DEEP SOUTH TEXAS.

* UNTIL 1230 AM CST

* AT 1137 PM CST…NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
SEVERE THUNDERSTORM…CAPABLE OF PRODUCING HALF-DOLLAR SIZE HAIL
AND DAMAGING 60 MPH WINDS…7 MILES NORTHWEST OF RAYMONDVILLE…
MOVING SOUTHEAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR…
YTURRIA.
LASARA.
RAYMONDVILLE.
LYFORD.
SEBASTIAN.
YZNAGA.
HIGHWAY 77.

 

Major Cold Outbreak by Monday; Rain Chances Looking Up!

As we’ve been advertising for days, a major arctic outbreak is preparing to invade the United States. This cold air will begin moving south into the northern plains by Friday and begin pushing into the Texas Panhandle and Northwest Texas during the morning hours on Sunday. Warm temperatures look to continue across Texas through the first half of the weekend.  Let’s start off by showing analyzing the current surface temperatures across North America.

Temperatures across Texas varied a bit today as a weak cold front moved across the state. In fact, we had a brief tornado issue in South Texas, but the storm remained over rural areas and moved offshore at 6 PM. Temperatures are cooler north of the front, but the real cold air is still confined in Canada and Alaska. Temperatures in western Canada and Alaska are between 20 and 30 degrees below zero with wind chills even colder. Since cold air is heavier than warm air, it is only a matter of time before that cold air moves south into the United States. This will be our first major cold outbreak this winter and will certainly make it feel like winter across parts of the United States.

Now lets get into the timing aspect for Texas. We’re still several days out so keep in mind the timing could change quite a bit over the coming days. That uncertainty also applies for rain chances. Those are much m ore complicated. These coming graphics are from the Global Forecast System Weather Model.

The cold front should already be approaching the Interstate 20/30 corridor by dinnertime on Sunday. The blue colors indicate temperatures that are at or below 32°F. I note that those freezing temperatures are already in the Texas Panhandle by Sunday evening. Temperatures quickly fall into the 50s and 40s in Northwest and North Texas as the cold front passes through. Winds will become gusty out of the north with a wind chill factor around 10 degrees below the actual air temperature.

By the morning hours on Monday, the cold front should have pushed south to areas like Austin, College Station, and Shreveport. Temperatures north of the front will be in the 30s and 40s with even lower temperatures in the Texas Panhandle. Wind chill factors will be in the 20s and 30s with strong north winds along and behind the cold front. The front will continue to push south during the day on Monday with temperatures struggling to rise during the daytime hours. For folks in the cold air, it’s going to be a cold, winter-like day.

The GFS Weather Model seems to stall out or slow down the cold front during the day on Monday. That could occur, but these fronts have a tendency to move farther south than indicated because cold air is denser (heavier) than warm air. Even if the cold front slows down on Monday, it will push through the remainder of Texas and be near Brownsville by Tuesday morning. We’ll be able to refine temperatures for next week as we get closer to the weekend.

Lets talk about something I’m sure interests everyone even more than the temperatures. What is the chance of rain across Texas? There certainly will be a chance of rain this weekend in portions of Texas as this cold front moves in. Right now, it looks like the best rain chances will be along and east of Interstate 35, but that is how it looks right now. That may not be how it looks tomorrow. The weather models have been changing things up a bit each day. Considering we’re still five days out, that is perfectly normal and our forecasts will likely have to be adjusted over the coming days. For now, I’ll leave you with this graphic showing how much rain may fall this weekend. Keep in mind this is from a weather model, so don’t think this is how it will look when things are said and done.

Stay Tuned! We’ll have additional updates on the upcoming cold outbreak on Wednesday.

TORNADO WARNING for Aransas, Calhoun, Refugio Counties

The <strong class=’StrictlyAutoTagBold’>Nationalstrong> Weather Service in Corpus Christi has just put out a <strong class=’StrictlyAutoTagBold’>tornadostrong> warning for Aransas, <strong class=’StrictlyAutoTagBold’>Calhounstrong>, Refugio Counties until 5:15 <strong class=’StrictlyAutoTagBold’>PMstrong>. Radar is showing a strong circulation that is now capable of producing a <strong class=’StrictlyAutoTagBold’>tornadostrong>. Take your safety precautions if you live in the <strong class=’StrictlyAutoTagBold’>pathstrong> of this storm. Center room of the house on the lowest floor with <strong class=’StrictlyAutoTagBold’>nostrong> windows.

BULLETIN – EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL <strong class=’StrictlyAutoTagBold’>WEATHER SERVICEstrong> CORPUS CHRISTI TX
423 <strong class=’StrictlyAutoTagBold’>PMstrong> <strong class=’StrictlyAutoTagBold’>CSTstrong> TUE DEC 4 2012

THE NATIONAL <strong class=’StrictlyAutoTagBold’>WEATHER SERVICEstrong> IN CORPUS CHRISTI HAS ISSUED A

* TORNADO WARNING FOR…
NORTHEASTERN ARANSAS COUNTY IN SOUTH TEXAS…
SOUTHWESTERN CALHOUN COUNTY IN SOUTH TEXAS…
EXTREME EASTERN REFUGIO COUNTY IN SOUTH TEXAS…

* UNTIL 515 <strong class=’StrictlyAutoTagBold’>PMstrong> <strong class=’StrictlyAutoTagBold’>CSTstrong>

* AT 417 <strong class=’StrictlyAutoTagBold’>PMstrong> <strong class=’StrictlyAutoTagBold’>CSTstrong>…NATIONAL <strong class=’StrictlyAutoTagBold’>WEATHER SERVICEstrong> DOPPLER RADAR INDICATED
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 7 <strong class=’StrictlyAutoTagBold’>MILESstrong>
NORTHWEST OF ARANSAS NATIONAL WILDLIFE REFUGE…OR 12 <strong class=’StrictlyAutoTagBold’>MILESstrong> WEST
OF SEADRIFT…MOVING SOUTHEAST AT 10 MPH.

* LOCATIONS IMPACTED INCLUDE…
ARANSAS NATIONAL WILDLIFE REFUGE…

 

11:30 AM Severe Weather Update; Increased Risk

The Storm Prediction Center has gone ahead and issued a formal severe weather risk for coastal regions of Texas between Houston southwest to Corpus Christi. Our thinking hasn’t changed much since our update this morning. The overall risk of severe storms has increased slightly along the coast thanks to higher instability values in combination of a local maximum of wind shear. This combination will promote the risk for large hail and damaging winds in the formal risk zone. I’m still expecting storms to be in progress by 1 PM with the risk continuing until 8 PM. The risk will end when the line of storms moves off the coast. Folks in Deep South Texas could be dealing with storms after 8 PM, but that’s just because they’re further south.

I’ll leave you with an instability graphic valid for this afternoon and advise you to check out this morning’s discussion for even more details.

 

Showers and Storms (some strong) in Southeast Texas later today

A weak cold front that is currently moving southeast across North <strong class=’StrictlyAutoTagBold’>Texasstrong> will be located in <strong class=’StrictlyAutoTagBold’>Southeaststrong> <strong class=’StrictlyAutoTagBold’>Texasstrong> later this afternoon. Seasonably high instability values along with the frontal forcing will allow for a broken line of showers and thunderstorms to develop. These storms should begin developing by mid-afternoon and move southeast towards Interstate 10 by 4 PM. It looks like Houston will have storms in the area just in time for rush hour.

While instability values support organized thunderstorms, wind shear in the atmosphere is fairly weak. This will limit the severe weather threat and thus we are only forecasting a marginal risk of severe weather this afternoon and early evening. The primary threats from <strong class=’StrictlyAutoTagBold’>todaystrong>’s storms will be brief heavy rainfall, cloud to ground lightning, small hail and occasional gusty winds. One or two storms may briefly reach severe limits with quarter size hail and damaging winds in excess of 60 MPH. If instability values are higher than expected, the probability of severe weather may increase. We’ll be monitoring the situation and providing coverage as the day unfolds!

 

[caption id="attachment_12262" align="aligncenter" width="595"] Tuesday Afternoon Instability Values[/caption]

[caption id="attachment_12263" align="aligncenter" width="595"] Tuesday Afternoon Wind Shear Values[/caption]

@TxStormChasers

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