FXUS62 KTAE 220729
AFDTAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
229 AM EST TUE DEC 22 2009
.SHORT TERM (TODAY THROUGH THURSDAY)...UPPER LEVEL FLOW ACROSS
THE SOUTHERN TIER OF STATES IS GENERALLY ZONAL THIS MORNING. UPPER
TROUGHS ARE SITUATED OVER THE PACIFIC NORTHWEST AND NEW ENGLAND. A
WEAK UPPER TROUGH IS EXITING THE EASTERN GULF OF MEXICO...TAKING
THE REMAINING HIGH CLOUDS WITH IT. UPPER PATTERN WILL EVOLVE OVER
THE NEXT SEVERAL DAYS WITH THE PACIFIC NORTHWEST TROUGH DIGGING
SOUTH AND BECOMING A MAJOR WINTER STORM OVER THE CENTRAL STATES.
AT THE SFC...HIGH PRESSURE OVER THE SOUTHEASTERN STATES WILL SLIDE
EAST THROUGH WEDNESDAY WITH LOW LEVEL FLOW GRADUALLY INCREASING
AND BECOMING EAST THEN SOUTHEAST. COLD FRONT ASSOCIATED WITH THE
DEVELOPING CENTRAL U.S. STORM WILL APPROACH THE FORECAST AREA BY
LATE THURSDAY.
IN TERMS OF SENSIBLE WEATHER...A COOL START TO TODAY WILL YIELD TO
MODERATING TEMPERATURES THIS AFTERNOON AS HEIGHTS RISE. MAX TEMPS
EXPECTED TO REACH LOWER TO MID 60S THIS AFTERNOON AND MID TO UPPER
60S BY WEDNESDAY AFTERNOON. WEDNESDAY MORNING LOWS SHOULD REACH THE
UPPER 30S BUT REMAIN WELL ABOVE FREEZING. DRY WEATHER IS EXPECTED
INTO WEDNESDAY NIGHT.
BY LATE WEDNESDAY NIGHT...ONSHORE FLOW WILL INCREASE AHEAD OF THE
DEEPENING LOW OVER THE MISSISSIPPI VALLEY. MAY SEE A SHOWER OR TWO
OVER THE WESTERN ZONES BEFORE SUNRISE THURSDAY...BUT RAIN CHANCES
NOT EXPECTED TO INCREASE SUBSTANTIALLY UNTIL THURSDAY AFTERNOON.
DESPITE WARMING LOW LEVELS AND STRONG SOUTHERLY FLOW...INSTABILITY
IS EXPECTED TO BE INSUFFICIENT FOR MORE THAN ISOLATED THUNDER
THURSDAY AFTERNOON. THIS LACK OF INSTABILITY WILL LIMIT THE RISK
OF SEVERE STORMS DESPITE STRONG SHEAR PROFILES.
.LONG TERM (THURSDAY NIGHT THROUGH NEXT TUESDAY)...THE LATEST GFS
SOLUTION HAS NOW COME MORE IN LINE WITH THE ECMWF IN THE TIMING
OF THE PASSAGE OF THE COLD FRONT. LAST NIGHT WE TOOK A BLEND OF
THE GFS AND ECMWF AND CONTINUED TO SHOW LINGERING CONVECTION OVER
THE EASTERN HALF OF OUR CWA AFTER 12Z FRIDAY. THE BULK OF THE
SHOWERS/TSTMS (LIKELY POPS) WILL OCCUR THURSDAY NIGHT AND THEN
WILL TAPER POPS FROM SILENT 10% WESTERN ZONES TO CHANCE EAST. BY
FRIDAY AFTERNOON THE FRONT SHOULD BE EAST OF THE LOCAL REGION WITH
MUCH DRIER AIR FILTERING FROM WEST TO EAST IN ITS WAKE. WE STILL
MAY SEE A FEW STRONG TO SEVERE STORMS WITH THIS SYSTEM BUT THE
BEST CHANCE WILL BE WELL TO OUR NORTH. ONCE THE FRONT MOVES
THROUGH...THE GFS/EURO SHOW A DISTURBANCE FORMING IN THE WESTERN
GULF ALONG THE SUBTROPICAL JET AXIS. THIS WOULD BRING SUBSTANTIAL
CLOUD COVER AND A SLIGHT CHANCE OF RAIN TO OUR FLORIDA ZONES
SATURDAY AFTERNOON AND EVENING. BOTH SOLUTIONS WEAKEN THE SYSTEM
AS IT MOVES EASTWARD SO NO SUBSTANTIAL RAINFALL IS EXPECTED. A DRY
AIRMASS WILL FILTER IN BEHIND THIS FEATURE KEEPING US RAIN-FREE
UNTIL TUESDAY AFTERNOON WHEN MODELS DEVELOP A COASTAL LOW IN THE
CENTRAL GULF AND BRING IT INTO THE SOUTHEASTERN U.S. FOR
NOW...HAVE INTRODUCED SILENT 10% POPS FOR THE AREA...BUT THESE MAY
NEED TO BE ADJUSTED UPWARD AS TIMING AND POSITION OF POSSIBLE LOW
BECOME MORE DEFINITE IN FUTURE MODEL RUNS. TEMPS WILL WARM UP TO
ABOVE CLIMO AS WE MOVE TOWARD THE HOLIDAY WEEKEND WITH A RAPID
COOL DOWN BEYOND CHRISTMAS BEHIND THE COLD FRONT. FROM SATURDAY
THROUGH THE END OF THE EXTENDED PERIOD...WE WILL SEE TEMPS
AVERAGING BELOW CLIMO WITH FREEZING TEMPERATURES POSSIBLE EARLY
NEXT WEEK.
&&
.AVIATION...A SOLID BAND OF CIRRUS CLOUDS THAT MADE FOR A
PICTURESQUE SUNSET THIS EVENING HAVE SHIFTED OFF TO THE EAST
BRINGING IN CLOUD-FREE SKIES. WITH HIGH PRESSURE OVER THE
REGION...WINDS ARE EXPECTED TO DIE DOWN AGAIN TONIGHT ALLOWING
FOR A RAPID COOL DOWN. VLD AND TLH MAY SEE BRIEF MVFR CONDITIONS
AS TEMPERATURES FALL TO NEAR THE DEWPOINT AND SUBSIDENCE ALLOWS
FOR FOG DEVELOPMENT. ANY FOG WILL QUICKLY DIMINISH BY MID MORNING
TUESDAY WITH SUFFICIENT HEATING. ELSEWHERE...VFR CONDITIONS WILL
PREVAIL THROUGH TONIGHT AND INTO TOMORROW EVENING. WINDS WILL
REMAIN CALM TONIGHT AND PICK UP DURING THE DAY TOMORROW BECOMING
EASTERLY BY TOMORROW NIGHT AS THE HIGH LIFTS OFF TO THE NORTHEAST.
&&
.MARINE...LIGHT FLOW EXPECTED TODAY WITH SFC HIGH PRESSURE NEARBY.
WINDS AND SEAS WILL BEGIN TO STEADILY INCREASE STARTING TONIGHT
AS HIGH PRESSURE SHIFTS EAST AND THE GRADIENT TIGHTENS WITH LOW
PRESSURE DEEPENING OVER THE PLAINS. SMALL CRAFT ADVISORY
CONDITIONS EXPECTED TO REACH THE WATERS WEDNESDAY NIGHT AHEAD OF
THE APPROACHING STORM SYSTEM WITH SEAS APPROACHING 10 FEET
OFFSHORE THURSDAY. NORTHWEST FLOW WILL KICK IN BEHIND THE FRONT
FOR FRIDAY WITH A GRADUAL DECREASE IN WINDS AND SEAS AS HIGH
PRESSURE BUILDS IN.
&&
.FIRE WEATHER...LONG DURATIONS OF LOW RELATIVE HUMIDITY ARE
EXPECTED TO MEET RED FLAG CRITERIA ACROSS MOST OF THE BIG BEND
THIS AFTERNOON SO WE UPGRADED THE FIRE WEATHER WATCH TO A RED FLAG
WARNING FOR THOSE ZONES. WE CANCELLED THE FIRE WEATHER WATCH FOR
THE REMAINING FLORIDA ZONES WHICH IS GADSDEN...LIBERTY AND
FRANKLIN COUNTIES WESTWARD THROUGH WALTON COUNTY. NO CONCERNS FOR
THE REMAINDER OF THE WORK WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TALLAHASSEE 64 37 66 48 72 / 0 0 0 10 50
PANAMA CITY 63 44 65 52 69 / 0 0 0 20 60
DOTHAN 62 38 62 47 67 / 0 0 0 20 60
ALBANY 62 36 63 45 66 / 0 0 0 10 50
VALDOSTA 62 37 65 47 70 / 0 0 0 10 40
CROSS CITY 64 37 69 48 71 / 0 0 0 10 30
APALACHICOLA 61 46 63 54 68 / 0 0 0 10 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...FROST ADVISORY UNTIL 7 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: HENRY...HOUSTON.
FREEZE WARNING UNTIL 7 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: COFFEE...DALE...GENEVA.
GA...FROST ADVISORY UNTIL 8 AM EST THIS MORNING FOR THE FOLLOWING
ZONES: BAKER...BEN HILL...CALHOUN...CLAY...DECATUR...
DOUGHERTY...EARLY...IRWIN...LEE...MILLER...MITCHELL...
QUITMAN...RANDOLPH...SEMINOLE...TERRELL...TIFT...TURNER...
WORTH.
FREEZE WARNING UNTIL 8 AM EST THIS MORNING FOR THE FOLLOWING
ZONES: BERRIEN...BROOKS...COLQUITT...COOK...GRADY...
LANIER...LOWNDES...THOMAS.
FL...FREEZE WARNING UNTIL 8 AM EST /7 AM CST/ THIS MORNING FOR THE
FOLLOWING ZONES: BAY...CALHOUN...COASTAL WALTON...DIXIE...
FRANKLIN...GADSDEN...GULF...HOLMES...INLAND WALTON...
JACKSON...JEFFERSON...LAFAYETTE...LEON...LIBERTY...
MADISON...TAYLOR...WAKULLA...WASHINGTON.
RED FLAG WARNING FROM 1 PM TO 5 PM EST THIS AFTERNOON FOR THE
FOLLOWING ZONES: DIXIE...JEFFERSON...LAFAYETTE...LEON...
MADISON...TAYLOR...WAKULLA.
GM...NONE.
&&
$$
CAMP/BARRY/AUSTIN
