From HGX AFD:
DISCUSSION...
AREA RADAR SHOWING ONE BAND OF RAIN PASSING THROUGH SE TX THIS
MORNING. T/TD ARE JUST ENOUGH ABOVE FREEZING THAT PRECIPITATION
SHOULD FALL AS RAIN. IF THERE ARE ANY INTENSE POCKETS OF
PRECIPITATION...POSSIBLE THAT A LITTLE BIT OF SLEET MAY MIX IN
WITH THE RAIN. AT THIS POINT...EXPECT RAIN BANDS TO DEVELOP AND
MOVE OVER THE REGION OVER THE NEXT 12 HRS AND HOLD TEMPS IN THE
UPPER 30S TO LOW 40S FOR MUCH OF THE DAY.
WATER VAPOR IMAGERY AND UPPER LEVEL ANALYSIS SHOW UPPER LOW MOVING
OVER TX/OK PANHANDLE. THERE IS A TRAILING VORTICITY MAX BACK OVER
THE DESERT SW. THIS FEATURE SHOULD CONTINUE TO SWING ACROSS MEXICO
TODAY/TONIGHT ALLOWING THE MAIN UPPER LOW TO DROP SOUTH OVER W TX
AND THEN ACROSS C TX BY 12Z TUE. DURING THE DAY TODAY...STRONG
UPPER LEVEL JET WILL MOVE INTO THE AREA WITH INCREASING DIVERGENCE
ALOFT. ALSO EXPECT LARGE OMEGA TO SPREAD OVER THE REGION IN
RESPONSE TO THE UPPER LEVEL LOW DROPPING INTO C TX. EXPECT
ISENTROPIC LIFT TO INCREASE ALONG WITH FRONTOGENETIC FORCING NEAR
850MB. WILL CONTINUE WITH HIGH RAIN CHANCES TODAY AND STILL THINK
SOLID 1-2 INCHES OF RAIN CAN BE EXPECTED ACROSS THE WHOLE AREA.
SOME OF THE STRONGER BANDS OF PRECIP COULD PRODUCE SOME HIGHER
TOTALS. OVERALL THE SCENARIO FOR TODAY HAS NOT CHANGED WITH ANY OF
THE SYNOPTIC MODELS OR HI RES MESOSCALE MODELS.
TUESDAY FORECAST REMAINS TRICKY ALTHOUGH THINK TEMP PROFILES IN
THE LOWER ATMOSPHERE WILL CONTINUE TO SUPPORT RAIN. UPPER LEVEL
LOW IS STILL EXPECTED TO TRACK OVER THE FORECAST AREA MAINLY
BETWEEN 12-18Z TUE. THERE IS EXPECTED TO BE LARGE UPWARD VERTICAL
MOTION ASSOCIATED WITH THE UPPER LOW RESULTING IN LARGE OMEGA. THE
MAIN QUESTION FOR PRECIPITATION TUESDAY WILL BE HOW QUICKLY THE
MOISTURE DECREASES WITH PASSAGE OF COLD FRONT WRAPPING AROUND THE
SFC LOW MOVING ALONG THE GULF COAST. IT SEEMS THAT THE FORCING AND
MOISTURE MAY BE JUST ENOUGH OUT OF PHASE TO ONLY REALLY GET RAIN
TO FALL. GFS/ECMWF SEEM TO HOLD ONTO JUST ENOUGH MOISTURE TO
WARRANT A MENTION OF SLEET FOR SOME OF THE NORTHERN COUNTIES BUT
REALLY THINK MAIN PRECIP WILL BE RAIN. WHILE SNOW/SLEET/RAIN MIX
MAY BE POSSIBLE IF LIFT/MOISTURE/TEMP PROFILES COME INTO BETTER
ALIGNMENT...THERE IS ONLY A SMALL TIME FRAME FOR THIS TO HAPPEN
TUE MORNING. IF WINTER PRECIP DOES OCCUR...DO NOT THINK THERE WILL
BE ANY ACCUMULATION.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE PLAINS AND TX ON
WED INTO THUR. EXPECT THERE TO BE MAINLY CLEAR SKIES AND WINDS
SHOULD DECOUPLE THUR MORNING TO MAKE FOR A COLD START TO
THANKSGIVING DAY. LIKELY HAVE TEMPS IN THE LOW/MID 20S NORTHEAST
OF HOUSTON. UPPER 20S WILL BE COMMON FOR MOST AREAS AND 30S ALONG
THE COAST. WE WILL LIKELY NEED TO LOOK AT FREEZE WATCH/WARNINGS
FOR AREAS THAT HAVE NOT OBSERVED A FREEZE YET.
OVERALL GOING INTO THE WEEKEND IT LOOKS LIKE A FAIRLY QUIET
WEATHER PATTERN. RETURN FLOW DOES SET UP SUN/MON NEXT WEEK SO MAY
GET A SHOWER OR TWO TO DEVELOP. TEMPS FOR THE WEEKEND SHOULD CLIMB
BACK TO NORMAL OR EVEN A COUPLE DEGREES ABOVE NORMAL AFTER HAVING
TEMPS SOME 15 DEGREES BELOW NORMAL.
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