Severe thunderstorms and tornado warnings are already up on Christmas morning in Texas. A slot of dry mid-level air is visible south of the warm front along the Texas - Lousiana Gulf Coast while humid air with dew points from the mid to upper 60 is blowing in from the south at low levels at speeds of up to 50 miles per hour. Very strong upper level winds are moving in from the southwest. This weather situation is unstable like sweating dynamite. Long track tornadoes may form in the dry slot.
Water vapor satellite imagery shows a slot of very dry air has formed above the Texas and Louisiana Gulf Coast. Because humid air lies below and there's strong wind shear, the dry air enhances downdraft formation. Strong downdrafts take spinning air downwards and contribute to tornado formation.
I have compiled graphics from the 3 key weather offices on the Gulf Coast: Houston Texas, New Orleans Louisiana and Mobile Alabama. Please read and heed their warnings if you live near the Gulf coast.
Houston NWS
"A warm front will remain over the College Station and Crockett areas this morning. A strong jet stream disturbance will move into Texas this morning. Severe thunderstorms capable of producing tornadoes, damaging winds and possibly even hail will be possible over the threat area gradually shifting east late in the morning and early afternoon. A cold front in North Texas will usher in much cooler temperatures by mid afternoon." NWS Houston
New Orleans NWS
Dangerous Severe Weather Outbreak Expected Today across the Entire North-central Gulf Coast... A potent weather system will impact the area today bringing with it a threat of widespread severe weather. A stalled front currently located from just north of Lake Charles to Poplarville will begin to slowly move north through the early morning hours. The severe weather threat will begin this morning as the stalled front moves northward as a warm front. As a surface low moves northeastward...the warm front will move farther inland and a cold front will surge toward the area from the west. Any thunderstorms that develop south of the warm front and ahead of the cold front will be capable of becoming severe with an enhanced risk for producing tornadoes. The Storm Prediction Center is currently indicating a Moderate Risk of severe weather for areas along and north of a line extending from Donaldsonville to Pascagoula...and a slight risk of severe weather for the remainder of the area. The main threats from any severe weather will be damaging straight line winds and tornadoes. Large hail will be possible...but is less likely. There is also a risk of significant severe weather across the region...defined as strong tornadoes(EF2 or greater) or winds greater than 75 miles per hour. This threat would be primarily during the afternoon and evening hours today and is possible across the entire much of the area. Severe weather will continue to be possible until the cold front sweeps through the area late this evening. Please take this time to review your severe weather safety plans and remember to monitor the weather tomorrow as this potentially dangerous situation unfolds
Mobile, Alabama NWS
AS THE DAY PROGRESSES...A SQUALL LINE WITH TORNADIC CELLS OUT AHEAD OF THE LINE WILL DEVELOP AND OVERTAKE THE AREA INTO THE AFTERNOON. LONG TRACKED TORNADOES WILL BE THE MAIN THREAT WITH THESE ISOLATED CELLS AHEAD OF THE LINE. THEN A LINE OF THUNDERSTORMS WILL FORM OUT WEST ALONG THE INTERSTATE 59 CORRIDOR IN MISSISSIPPI AND WILL RACE EASTWARD...REACHING THE INTERSTATE 65 CORRIDOR BY EARLY EVENING. THE PRIMARY SEVERE WEATHER CONCERN ALONG THE SQUALL LINE WILL BE DAMAGING STRAIGHT LINE WINDS OF 60 TO 80 MPH AND LARGE HAIL...BUT AN ISOLATED TORNADO WILL STILL BE POSSIBLE. BRIEF... TORRENTIAL DOWNPOURS ARE ALSO LIKELY...BUT DUE TO THE SPEED OF THE SYSTEM...FLOODING SHOULD BE KEPT TO A MINIMUM.
A LINE OF THUNDERSTORMS WILL FORM OUT WEST ALONG THE INTERSTATE 59 CORRIDOR IN MISSISSIPPI AND WILL RACE EASTWARD...REACHING THE INTERSTATE 65 CORRIDOR BY EARLY EVENING AND WILL CONTINUE RAPIDLY EASTWARD THROUGH THE REMAINDER OF THE EVENING. THE PRIMARY SEVERE WEATHER CONCERN ALONG THE SQUALL LINE WILL BE DAMAGING STRAIGHT LINE WINDS OF 60 TO 80 MPH AND LARGE HAIL...BUT AN ISOLATED TORNADO WILL STILL BE POSSIBLE. BRIEF...TORRENTIAL DOWNPOURS ARE ALSO LIKELY...BUT DUE TO THE SPEED OF THE SYSTEM...FLOODING SHOULD BE KEPT TO A MINIMUM.
Tomorrow this system moves into the Carolinas. A dangerous situation can be expected from the central Carolinas to the coast. NOAA's Severe weather Prediction Center just upgraded the severe weather outlook for the Carolinas tomorrow to moderate. I have never seen anything like this before for the Carolinas in December.