HAMweather.com Area Forecast Discussion for County Warning Area HUN

Thu, 16 Feb 2012 12:28:40 GMT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
556 AM CST THU FEB 16 2012

.UPDATE...
FOR 12Z TAFS

.DISCUSSION...
/ISSUED 400 AM CST THU FEB 16 2012/
10Z SURFACE ANALYSIS INDICATES THAT A WEAK WARM FRONT HAS MOVED
NORTHEAST OF THE FORECAST AREA...AS DEWPOINT TEMPS HAVE INCREASED TO
AROUND 50 TO THE LOWER 50S FROM THE MID TO UPPER 40S SINCE 06Z. BOTH
THE NAM AND GFS MODELS ARE IN FAIR AGREEMENT IN MOVING THE TRAILING
COLD FRONT INTO NORTHWEST ALABAMA BY AROUND 12Z AND ON THROUGH THE
REST OF THE FORECAST AREA BEFORE 18Z TODAY. THE LARGER AREA OF
SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUES TO SHIFT EAST OF THE
FORECAST AREA AS OF 10Z...WITH SOME SCATTERED SHOWERS ALONG AND JUST
AHEAD OF THE COLD FRONT IN NORTHEAST MISSISSIPPI. WILL CONTINUE WITH
CHANCE PRECIP PROBABILITIES ACROSS THE AREA THIS MORNING DUE TO THE
TIMING OF THE FRONT AND DECENT LOW LEVEL MOISTURE AND LIFT ALONG AND
AHEAD OF THE FRONT.

THE NAM MODEL IS MORE AGGRESSIVE INVOLVING CLEARING OUT THE FORECAST
AREA BY THIS EVENING AND OVERNIGHT TONIGHT COMPARED TO THE SLOWER
SOLUTION OF THE GFS. HAVE DECIDED TO COMPROMISE AND GO WITH PARTLY
CLOUDY WORDING TO ACCOUNT FOR EXPECTED CONTINUED NORTHEAST MOVEMENT
OF MID AND HIGH CLOUDS INTO THE FORECAST AREA FROM LOUISIANA AND
TEXAS. ANOTHER PACIFIC HIGH IN THE ZONAL FLOW WILL PUSH EASTWARD
ACROSS THE AREA PROGRESSIVELY LATER TONIGHT THROUGH FRIDAY. IN THE
MEANTIME...AN UPPER LOW JUST EAST OF THE BAJA CALIFORNIA COAST AT 06Z
TONIGHT WILL MOVE EAST-NORTHEAST IN THE SOUTHERN JET STREAM INTO WEST
TEXAS BY FRIDAY EVENING...WITH SHOWERS EXPECTED TO DEVELOP IN THE
RETURN FLOW MOISTURE OFF OF THE GULF OF MEXICO INTO TEXAS AND
OKLAHOMA.

THE UPPER LOW DOES OPEN UP ON FRIDAY AFTERNOON AS IT MOVES THROUGH
NEW MEXICO AND CONTINUES TO REFLECT A SURFACE LOW ALONG THE OLD COLD
FRONTAL BOUNDARY WELL TO THE SOUTH OF THE FORECAST AREA IN SOUTH
MISSISSIPPI BY 18Z SATURDAY. DECENT LOW TO MID LEVEL ISENTROPIC
LIFTING WILL RESULT IN STEADY TO MODERATE RAIN ACROSS MUCH OF THE
FORECAST AREA ESPECIALLY BY SATURDAY AFTERNOON AS PER THE ECMWF/GFS
AND NAM MODELS. WILL CONTINUE WITH AT LEAST HIGH END LIKELY POPS FOR
NOW FOR SATURDAY AND SATURDAY NIGHT. THE MODELS ARE SIMILAR IN
WRAPPING AROUND A DECENT AREA OF PRECIP TO THE NORTHWEST OF THE
SURFACE LOW ACROSS MUCH OF KENTUCKY AND TENNESSEE BETWEEN 06-12Z
SUNDAY.

AT THIS POINT...THERE DOES NOT APPEAR TO BE ENOUGH COLD AIR MOVING
SOUTHWARD INTO THE SYSTEM TO MENTION ANY FREEZING OR FROZEN
PRECIPITATION...BUT THIS WILL NEED TO BE WATCHED INVOLVING THE NEXT
MODEL RUN TO SEE IF THE TIMING OF THE SYSTEM AND DEPTH OF THE COLD
AIR FILTERING INTO THE REGION CHANGES. THE PRECIP SHOULD END SHORTLY
AFTER 12Z ON SUNDAY...WITH A LARGER AREA OF SURFACE HIGH PRESSURE
EXPECTED TO SETTLE SOUTHEAST INTO THE LOWER OHIO AND TENNESSEE VALLEY
AND THE APPALACHIAN AREAS THROUGH MONDAY. SINCE THE HIGH PRESSURE
AREA IS PROGGED BY ALL OF THE EXTENDED MODELS TO BE SLIGHTLY SLOWER
IN ITS EASTWARD MOVEMENT OFF OF THE ATLANTIC COAST THROUGH MONDAY...WILL
DELAY PRECIP CHANCES IN EXTENDED FORECAST UNTIL TUESDAY.

THE EUROPEAN AND GFS MODELS ARE ALSO NOW SLOWER INVOLVING THE
EASTWARD PROGRESSION OF THE NEXT UPPER LOW THAT WILL BE PUSHING
THROUGH THE SOUTHERN PLAINS BY 00Z WEDNESDAY. WILL CONTINUE WITH AT
LEAST A SLIGHT CHANCE OF SHOWERS FOR TUESDAY. HAVE SLIGHTLY UPPED
POPS FOR WEDNESDAY INTO THE HIGHER CATEGORY OF THE CHANCE PROBABILITY
ACROSS THE FORECAST AREA. TEMPS LOOK GENERALLY GOOD AND HAVE ACCEPTED
GFS NUMBERS.

TT

.AVIATION...
FOR 12Z TAFS...LINE OF -SHRA CONTINUES TO PUSH EWD AND WILL IMPACT
HSV DURING FIRST HOUR OF TAF PERIOD. OTHERWISE...EXPECT TERMINALS
TO REMAIN FREE OF PRECIP FOR AT LEAST THE NEXT 24 HOURS. MVFR CIGS
WILL LIKELY DROP BELOW 2 KFT FOR A FEW HOURS THIS MORNING BEFORE
LIFTING TO AROUND 2500 FT AROUND 16/15Z. MODEL GUIDANCE IS CONSISTENT
WITH UPSTREAM SATELLITE DATA IN SUGGESTING THAT STRATUS WILL
LIFT/SCATTER BY LATE MORNING. THE CLEARING TREND WILL CONTINUE
OVERNIGHT...WITH CONDITIONS BECOMING FAVORABLE FOR THE FORMATION OF
LIGHT BR AND MVFR VSBY TO 5 SM. LGT/VRBL TO LGT NW SURFACE WINDS WILL
INCREASE TO AROUND 10 KNOTS FROM THE NNW THIS AFTERNOON...WITH A
LIGHT NNE WIND EXPECTED OVERNIGHT.

70/DD

.HUN WATCHES/WARNINGS/ADVISORIES...

AL...NONE.

TN...NONE.