NPWHGX) FOR DETAILS ON THE UPCOMING POTENTIALLY DANGEROUS WINTER WEATHER EVENT. 42 && .PREV DISCUSSION... /ISSUED 616 PM CST WED FEB 2 2011/ AVIATION... VFR THROUGH TOMORROW AFTERNOON...HIGH TO MID LEVEL DECK STREAMING UP FROM THE SOUTHWEST THROUGH PERIOD AS THE JET STREAM/CORE POSITIONS ITSELF OVER EASTERN TEXAS. THE UPPER LOW MOVING OUT OF NORTHERN MEXICO AND INTO THE BIG BEND TOMORROW AFTERNOON WILL AID IN PULLING UP MORE MOISTURE-RICH AIR (UPON ENHANCED MID-LEVEL SOUTHWESTERLIES) OVER TOP A SUB-FREEZING LOWER 10 K FEET. MID TO LATE AFTERNOON PRECIPITATION WILL MOST LIKELY BEGIN AS A FROZEN MIXTURE FOR MANY HUBS...MOST LIKELY TRANSITIONING OVER TO ALL SNOW (-SHSN) GOING INTO THE LAST FEW HOURS OF THE PERIOD. TIME OF ONSET AND COVERAGE IS STILL A MYSTERY...BUT CONFIDENCE IS STRENGTHENING THAT WINTRY PRECIPITATION OF EITHER MID TO LATE AFTERNOON FREEZING RAIN/SLEET/ FLURRIES WILL TRANSITION TO LIGHT SNOW SHOWERS BY THE END OF THE DAY. 31 PREV DISCUSSION... /ISSUED 334 PM CST WED FEB 2 2011/ .WINTER STORM WATCH FOR ALL OF SE TX THURSDAY AFTERNOON THROUGH FRIDAY MORNING... DISCUSSION... PARTIAL CLEARING ACROSS SE TX HAS ALLOWED TEMPS TO AT LEAST BRIEFLY CLIMB ABOVE FREEZING ACROSS THE SRN HALF OF THE AREA. HOWEVER...TEMPS HAVE REMAINED BELOW FREEZING ALL DAY ACROSS THE NW HALF. MID LEVEL CLOUDINESS WILL GRADUALLY FILL IN ACROSS THE AREA TONIGHT. IN ADDITION...WINDS ARE EXPECTED TO STAY UP IN THE 5-15 MPH RANGE. AS A RESULT...ONLY A SLOW DROP IN TEMP IS EXPECTED TONIGHT. HAVE TRENDED TEMPS SLIGHTLY ABOVE MAVMOS AS A RESULT. REGARDLESS...THE HARD FREEZE WILL CONTINUE...AND THE WARNING WILL REMAIN IN EFFECT THROUGH NOON THURSDAY. GIVEN THE THICK CLOUD COVER ON THURSDAY...TEMPS WILL STRUGGLE TO CLIMB ABOVE FREEZING IN THE AFTN. WATER VAPOR IMAGERY SHOWS A STRONG UPPER LOW ACROSS NORTHERN NEW MEXICO THIS AFTERNOON. THIS SYSTEM WILL CONTINUE DIGGING SOUTH TOWARD THE BIG BEND REGION TONIGHT/THURSDAY...THEN LIFT EASTWARD ACROSS TEXAS THU NIGHT/FRIDAY. UPPER FLOW WILL BECOME INCREASINGLY DIFFLUENT WITH SE TX POSSIBLY GOING INTO THE RIGHT REAR OF A 300 MB JET MAX THU NIGHT. ATMOSPHERIC MOISTURE WILL BEGIN TO DEEPEN THURSDAY WITH PWS APPROACHING AN INCH NEAR THE COAST. AS THE SYSTEM APPROACHES...ISENTROPIC LIFT WILL DEVELOP ACROSS SE TX BEGINNING LATE TONIGHT/THU MORNING. AS IS TYPICAL IN THESE SITUATIONS THE ONSET OF PRECIP IS DIFFICULT TO TIME. THE ATMOSPHERE WILL SATURATE FOR SEVERAL HOURS BEFORE PRECIP WILL REACH THE GROUND. THE MODELS HAVE TRENDED FASTER WITH PRECIP DEVELOPMENT IN THE LAST COUPLE OF RUNS. A FEW FLURRIES WILL BE POSSIBLE AS EARLY AS LATE TONIGHT NEAR THE COAST...AND OVER THE SOUTHERN HALF OF THE AREA THU MORNING. HOWEVER...THINKING THAT THE MORE SIGNIFICANT LIGHT PRECIPITATION WILL DEVELOP BEGINNING MIDDAY NEAR THE COAST...MID AFTERNOON CENTRAL ZONES...AND LATE AFTN OVER THE NORTH. THE MAIN PRECIP EVENT WILL GET GOING LATE AFTN/EARLY EVENING AND PERSIST THROUGH EARLY MORNING FRIDAY. PRECIP TYPE: EXPECTING VERY LIGHT SNOW OR SLEET NEAR THE COAST AT THE ONSET THURSDAY...WITH JUST SNOW FLURRIES OVER THE NORTHERN HALF. BY THURSDAY EVENING...SOUTHWEST WINDS ALOFT RESULT IN SOME WARMING IN THE PROFILE IN THE 700-900 MB LEVEL. THIS WARMING WILL RESULT IN THE POTENTIAL FOR A MIX OF FREEZING RAIN OVER THE SE THIRD OF THE AREA. CURRENT THINKING IS THE WESTERN EXTENT OF THE FREEZING RAIN THREAT AREA WILL RUN FROM A MATAGORDA TO DOWNTOWN HOUSTON TO RYE LINE. WEST OF THIS LINE...SLEET AND SNOW ARE EXPECTED...WITH ALL SNOW OVER THE NW HALF OF THE CWA. EAST OF THIS LINE...A MIX OF FREEZING RAIN...SLEET...AND SNOW ARE EXPECTED...WITH MAINLY ICE EXPECTED ACROSS SOUTHERN BRAZORIA... SOUTHERN GALVESTON...CHAMBERS...AND SOUTHERN LIBERTY COUNTIES. THIS THINKING REFLECTS THE 12Z GFS SOLUTION WHICH IS A GOOD COMPROMISE BETWEEN THE MODELS. AMOUNTS: IN THE SNOW AND SLEET AREA EXPECTING ACCUMULATIONS OF 1 TO 3 INCHES WITH ISOLATED TOTALS AROUND 4 INCHES. THE BEST CHANCE OF 4 INCH ACCUMULATIONS WILL BE ACROSS THE PINEY WOODS AND LAKES AREA OF EAST TEXAS. IN THE ICE AREA (FAR SE)...ICE ACCUMULATIONS OF 1/10 TO 1/4 INCH ARE EXPECTED. IMPACTS: THE MAIN DIFFERENCE BETWEEN THIS EVENT AND THE WINTER WEATHER EVENTS OVER SE TX THE LAST COUPLE OF YEARS WILL BE THE COLDER TEMPERATURES. DUE TO THE VERY LOW DEWPOINTS AND EVAPORATIVE COOLING...TEMPERATURES WILL RUN 5 TO 7 DEGREES COLDER WITH THIS EVENT. THESE COLDER TEMPERATURES WILL RESULT IN A MUCH HIGHER LIKELIHOOD OF ROADS BECOMING ICED OVER...EVEN WITH LIGHT PRECIPITATION AMOUNTS. THIS WILL ESPECIALLY BE THE CASE WITH ELEVATED SURFACES LIKE BRIDGES AND OVERPASSES. ROAD CONDITIONS ARE EXPECTED TO DETERIORATE BEGINNING AROUND SUNSET THURSDAY. IN ADDITION... POWER OUTAGES WILL BE POSSIBLE ESPECIALLY IN THE FREEZING RAIN THREAT AREA. PRECIP IS EXPECTED TO TAPER OFF MID TO LATE MORNING FRIDAY AS BEST LIFT SHIFTS EAST OF THE AREA. SOME FREEZING DRIZZLE WILL BE POSSIBLE ON THE BACK SIDE OF THE SYSTEM BUT HAVE NOT REFLECTED THIS IN THE FORECAST AT THIS TIME. TEMPS SHOULD CLIMB TO THE MID 30S FRI AFTN WHICH SHOULD ALLOW FOR SOME TEMPORARY IMPROVEMENT IN ROAD CONDITIONS. HOWEVER...REFREEZING WILL BE POSSIBLE FRI NIGHT. HAVE LOWERED FCST MIN TEMPS FRIDAY NIGHT...WITH CLEAR SKIES AND LIGHT WINDS ALLOWING FOR ONE MORE HARD FREEZE. SUNSHINE EXPECTED SATURDAY WHICH WILL FINALLY ALLOW ALL OF SE TX TO CLIMB ABOVE FREEZING BY LATE MORNING. HIGHS IN THE 50S ARE EXPECTED. SUNDAY LOOKS LIKE A GREAT DAY WITH SUNSHINE AND MAX TEMPS IN THE UPPER 50S/60S. HAVE NOT MADE ANY CHANGES TO THE FORECAST BEYOND SUNDAY... WITH THE GFS/ECMWF STILL SHOWING MAJOR DIFFERENCES WITH THE TIMING OF THE NEXT FRONT. 35/46/38/33 MARINE... WILL MAINTAIN THE SCA FOR COASTAL WATERS TONIGHT THROUGH TOMORROW AFTN WITH AN SCEC FOR THE BAYS DURING THAT SAME TIME FRAME. WINDS HAVE BEEN MARGINAL FOR THE SCA FOR THE NEARSHORE WATERS BUT THERE IS ENOUGH UNCERTAINTY TO KEEP THINGS IN PLACE. SIMILAR THEORY FOR THE BAYS WITH THE SCEC. WINDS/SEAS TO LEVEL OFF AREAWIDE SAT AFTN THROUGH SUN AS HIGH PRESSURE SETTLES OVER THE AREA. THE NEXT COLD FRONT IS STILL PROGGED TO CROSS INTO THE COASTAL WATERS SUN NIGHT INTO MON WITH ADVISORIES LIKELY ONCE AGAIN. 41 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 18 31 23 36 23 / 10 20 70 50 10 HOUSTON (IAH) 22 33 27 36 23 / 10 40 70 60 10 GALVESTON (GLS) 27 35 30 36 32 / 10 50 70 60 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...HARD FREEZE WARNING UNTIL NOON CST THURSDAY FOR THE FOLLOWING ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS... COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS... HOUSTON...JACKSON...LIBERTY...MADISON...MATAGORDA... MONTGOMERY...POLK...SAN JACINTO...TRINITY...WALKER... WALLER...WASHINGTON...WHARTON. WINTER STORM WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING FOR THE FOLLOWING ZONES: AUSTIN...BRAZORIA... BRAZOS...BURLESON...CHAMBERS...COLORADO...FORT BEND... GALVESTON...GRIMES...HARRIS...HOUSTON...JACKSON...LIBERTY... MADISON...MATAGORDA...MONTGOMERY...POLK...SAN JACINTO... TRINITY...WALKER...WALLER...WASHINGTON...WHARTON. GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH FRIDAY AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY. SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$