Forecast for slight risk on the 8th and 9th for South Texas and Southern States.
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1151 PM CST SUN JAN 06 2013
VALID 081200Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTH TX...
...SOUTH TX...
SWRN U.S. UPPER LOW IS EXPECTED TO DIG SEWD INTO NRN MEXICO AND
EJECT TOWARD THE LOWER RIO GRAND RIVER VALLEY LATE IN THE PERIOD.
IN FACT IT APPEARS WEAK HEIGHT FALLS WILL NOT SPREAD INTO DEEP SOUTH
TX UNTIL AFTER MIDNIGHT. FOR THIS REASON IT APPEARS THE GREATEST
RISK FOR ORGANIZED SEVERE DEEP CONVECTION WILL OCCUR DURING THE
LATTER HALF OF THE PERIOD.
CURRENT THINKING IS MARITIME TROPICAL AIRMASS WILL STRUGGLE A BIT TO
MOVE INLAND DURING THE DAY2 PERIOD BUT FAVORABLE SELY TRAJECTORIES
OFF THE WRN GULF BASIN WILL CERTAINLY ALLOW MID-UPPER 60S SFC DEW
POINTS TO ADVECT INTO SOUTH TX AS COASTAL/WARM FRONT ADVANCES NWD.
WHILE THE NAM AND GFS ARE A BIT DIFFERENT IN THEIR TIMING OF PACIFIC
COLD FRONT SWEEPING INTO SOUTH TX THERE IS LITTLE DOUBT THAT
STRENGTHENING LOW LEVEL WARM ADVECTION WILL DRIVE WIDESPREAD
ELEVATED CONVECTION WITHIN WARM CONVEYOR. AFTER 00Z THE SUPERCELL
THREAT WILL INCREASE ACROSS DEEP SOUTH TX AS 70-80KT MID LEVEL SPEED
MAX BEGINS TO ROTATE TOWARD THE REGION. FORECAST PROFILES EXHIBIT
VERY STRONG SHEAR WITH MORE THAN ADEQUATE BUOYANCY AND NEAR-SFC
BASED INSTABILITY TO WARRANT A THREAT FOR ISOLATED TORNADOES
ALONG/SOUTH OF THE WARM FRONT. ADDITIONALLY...A SQUALL LINE MAY
ULTIMATELY EVOLVE ALONG THE ADVANCING COLD FRONT WHICH SHOULD SPREAD
TOWARD THE LOWER TX COAST BY DAYBREAK. DAMAGING WINDS AND PERHAPS
EVEN SOME HAIL MAY ACCOMPANY THIS ACTIVITY AS WELL.
..DARROW.. 01/07/2013
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0219 AM CST MON JAN 07 2013
VALID 091200Z - 101200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SERN TX/LOWER MS
VALLEY...
...SERN TX/LOWER MS VALLEY...
07/00Z ECMWF IS THE FAVORED MODEL THIS EVENING REGARDING THE
EVOLUTION OF UPPER LOW AS IT EJECTS ACROSS NRN MEXICO ACROSS NWRN TX
INTO CNTRL OK. IT APPEARS A STRONG MID LEVEL SPEED MAX WILL
TRANSLATE INTO THE SERN QUADRANT OF THE UPPER LOW BY THE START OF
THE PERIOD THEN TRANSLATE TOWARD ERN TX WITH THE LEADING EDGE OF
STRONGER FLOW/HEIGHT FALLS EXPECTED NEAR THE SABINE RIVER BY EARLY
EVENING.
BY WEDNESDAY VERY MOIST MT AIRMASS WILL SPREAD ACROSS THE WRN GULF
BASIN AND PW VALUES ON THE ORDER OF 1.5-2 INCHES WILL ADVECT INLAND
ACROSS THE WARM SECTOR AND INTERIOR AS FAR NORTH AS I-20 WHERE A SFC
WARM FRONT SHOULD ADVANCE AHEAD OF WEAK SFC LOW. VERY MOIST BUT
POOR LAPSE RATE WARM SECTOR ENVIRONMENT SHOULD YIELD MORE THAN
ADEQUATE CAPE FOR NEAR SFC-BASED CONVECTION AHEAD OF SLOW MOVING
PACIFIC COLD FRONT. CONSIDERABLE AMOUNT OF CONVECTION...MUCH OF IT
ELEVATED...WILL BE NOTED WITHIN THE WARM CONVEYOR THROUGH THE PERIOD
WITH HEAVY RAIN POSSIBLE GIVEN THE AFOREMENTIONED PW VALUES.
FORECAST SHEAR PROFILES CERTAINLY SUGGEST SUSTAINED ROTATING
UPDRAFTS AND PERHAPS A FEW SUPERCELLS ARE POSSIBLE BUT ONE OR MORE
SQUALL LINE-TYPE MCSS MAY ULTIMATELY EVOLVE ALONG LEADING EDGE OF
STRONGER FORCING/COLD FRONT. FOR THIS REASON THE GREATEST SEVERE
RISK MAY BE DAMAGING WINDS BUT ISOLATED TORNADOES ALSO SEEM POSSIBLE
GIVEN THAT SFC DEW POINTS SHOULD RISE INTO THE UPPER 60S ACROSS THE
COASTAL PORTIONS OF THE OUTLOOK.
..DARROW.. 01/07/2013
