000 FXUS62 KTAE 060643 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 242 AM EDT MON JUL 6 2009 .SYNOPSIS...ONGOING WEATHER IN OUR CWA HAS SIGNIFICANTLY WEAKENED OVER THE PAST FEW HOURS WITH AN AREA OF STRATIFORM PRECIP ACROSS MUCH OF SOUTH CENTRAL GEORGIA. A FEW WEAK CONVECTIVE CELLS CONTINUE TO DEVELOP ACROSS THE EASTERN FLORIDA PANHANDLE AND IN SOUTHWEST GEORGIA. ELSEWHERE IN THE SOUTHEAST...THERE ARE SEVERAL BANDS OF STORMS ALONG AND SOUTH OF THE FRONTAL BOUNDARY CURRENTLY IN THE CAROLINAS...TENNESSEE...ARKANSAS BACK INTO TEXAS. AT 06Z...TEMPS IN THE CWA WERE IN THE MID TO UPPER 70S...EXCEPT IN THE 80S ALONG THE COAST...DEWPOINTS WERE MOSTLY IN THE 70S. THE SURFACE MAP THIS MORNING SHOWS THAT THE 1008-MB LOW IS NOW CENTERED IN NORTH CAROLINA WITH THE FRONTAL BOUNDARY EXTENDING ACROSS THE TENNESSEE VALLEY... THEN SOUTHWEST INTO THE RIO GRANDE VALLEY. HIGH PRESSURE IS BUILDING INTO THE CENTRAL PLAINS STATES. THE ATLANTIC RIDGE AT THE SURFACE HAS SAGGED FARTHER SOUTH AND IS CURRENTLY SITUATED IN THE FLORIDA STRAITS EXTENDING AS FAR WEST AS THE WESTERN GULF OF MEXICO. ALOFT...THE RIDGE ALOFT IS STACKED NEARLY OVER THE SURFACE RIDGE. THE CENTER OF THE UPPER ANTICYCLONE IS NOW WEST OF BAJA. FLOW CONTINUES TO BE SOMEWHAT ZONAL ACROSS CONUS WITH A TROUGH IN THE EAST...RIDGE IN THE INTER MOUNTAIN WEST...AND A TROUGH JUST OFF THE COAST IN THE PACIFIC NORTHWEST. WV IMAGERY DEPICTS THE HIGH MOISTURE CONTENT QUITE WELL ALONG AND SOUTH OF THE FRONTAL BOUNDARY EXTENDING BACK INTO NORTHWEST MEXICO. && .SHORT TERM (TODAY THROUGH WEDNESDAY)... THE FRONTAL BOUNDARY WILL CONTINUE TO SAG EVER SO SLOWLY SOUTHWARD OVER THE NEXT FEW DAYS IN RESPONSE TO THE UPPER TROUGH...FOCUSING MOISTURE AND INSTABILITY ALONG AND SOUTH OF THE FRONT. THE UPPER ANTICYCLONE WILL RETURN TO THE SOUTHWEST U.S. ON WEDNESDAY...WHICH APPEARS TO AMPLIFY AND FOCUS THE TROUGH IN THE SOUTHERN MISSISSIPPI VALLEY. THE FRONTAL BOUNDARY WILL THEN SLIP EVEN FARTHER SOUTH ON WEDNESDAY PROBABLY INTO OUR CWA INCREASING THE UNCERTAINTY FOR OUR NORTHERN ZONES...WILL IT BE CLEARING SKIES...WARMER TEMPS OR JUST ANOTHER WET DAY. TODAY WILL BE QUITE DISTURBED...CATEGORICAL POPS...COOLER MAX TEMPS. OUR WORKSTATION WRF AGREES...DEVELOPING A MCS IN SOUTHEAST ALABAMA... WHICH THEN MOVES SOUTHEAST THROUGH THE ENTIRE CWA...CLEARING THE CWA BY 03Z WITH NEARLY 100 PERCENT COVERAGE THROUGH THE AFTERNOON. WILL BE GOING WITH TEMPS IN THE MID TO UPPER 80S TODAY...A TAD BIT WARMER ON TUESDAY WITH POPS IN THE 60 AND 70 PERCENT RANGE. FOR WEDNESDAY... TEMPS WILL BE IN THE UPPER 80S TO NEAR 90 WITH POPS RANGING FROM 60 PERCENT SOUTH AND 30-40 PERCENT NORTH. .LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... ONLY MINOR TWEAKS WERE MADE TO THE EXTENDED. PERIOD BEGINS WITH GLOBAL MODELS IN GOOD AGREEMENT. ALOFT...THIS PERSISTENT SUMMER PATTERN HIGHLIGHTED BY MEAN COOL TROUGHS CENTERED IN CLOSE PROXIMITY TO PAC NW COAST AND ALONG ERN SEABOARD WITH A BROAD HOT RIDGE IN BETWEEN CENTERED OVER CENTRAL PLAINS WITH AXIS SW TO HIGH OVER TX/NM BORDER. UPPER LOWS REMAIN INVCNTY OF OREGON/WASH COAST JUST OFF N ENGLAND. THE WESTWARD EXTENSION OF THE ATLANTIC RIDGE IS APPROACHING BAHAMAS. GFS/ECMWF IN GOOD AGREEMENT DURING DAYS 4/5 WITH NW FLOW ACROSS SE REGION. THEY SHOW PLAINS RIDGE ADVANCING EWD WITH A SERIES OF SHORTWAVES DROPPING DOWN FRONT SIDE AND INTO THE EXTREME SOUTHEAST STATES ALLOWING ERN TROUGH TO SHARPEN OFF ATLC COAST WHILE ATLANTIC RIDGE INTENSIFIES BACK TO THE WEST FROM BAHAMAS WWD INTO CENTRAL FLORIDA AND KEEPING A WEAKNESS IN THE SUBTROPICAL RIDGE ACROSS THE SE U.S. AS A RESULT...A DIFFLUENT PATTERN EVOLVES OVER THE SOUTHEAST STATES AND ESPECIALLY NE GULF REGION RESULTING IN FAVORABLE CONDITIONS FOR CONVECTION ESPECIALLY DAYS 4-5. AT THE SURFACE...HIGH PRESSURE RIDGE AXIS CONTINUES ACROSS SOUTHERN FL THROUGH LATE THURSDAY KEEPING SOUTHWEST FLOW IN PLACE. THE RIDGE AXIS THEN LIFTS NORTHWARD TO ACROSS CENTRAL FL FRIDAY AND REMAINS IN PLACE THROUGH SUNDAY. MEANWHILE...BERMUDA RIDGE EXPANDS WESTWARD INTO FL. UPPER TROUGH CONTINUES TO FOCUS MOISTURE AND INSTABILITY (WITH CONTINUING SERIES OF SHORTWAVES) ON PERSISTENT TROUGH/ BOUNDARY ACROSS N FL WED...BUT THEN BOUNDARY BEGINS TO DISSIPATE LATE THURS AS UPPER RIDGE BUILD EWD SHUNTING UPPER TROUGH AXIS E OF CWA AND FL RIDGE CONTS NWD. ACCORDINGLY POPS WILL SLOWLY DECREASE THRU PERIOD. ALTHOUGH IN BETTER AGREEMENT THAN PREVIOUS RUNS...GFS/ECMWF STILL DIVERGE MODESTLY TOWARDS THE END OF THE PERIOD AND ESPECIALLY HOW FAR EAST THE UPPER RIDGE WILL EXPAND EWD. BUT OVERALL...CWA REMAINS BETWEEN EXPANDING CENTRAL U.S. RIDGE AND ON BACK SIDE OF THE UPPER TROUGH. THE GFS EXPANDS LARGE SUBTROPICAL RIDGE EASTWARD INTO THE SE STATES...WHILE THE ECMWF A TAD LESS AGGRESSIVE ALLOWING UPPER TROUGH TO PENETRATE FURTHER INTO THE SE U.S. ALL IN ALL...UNSETTLED WEATHER PATTERN THROUGH THE EXTENDED PERIOD DOMINATED BY LINGERING FRONTAL BOUNDARY DRAPED ACROSS THE AREA...UPPER LEVEL TROUGH WITH ENERGY/ DISTURBANCES TRAVERSING THE AREA...AND HIGH ATMOSPHERIC MOISTURE AND WARM TEMPERATURES. THIS COMBINATION TRANSLATES TO LIKELY SHOWERS AND THUNDERSTORMS WED NIGHT THRU THURS...THEN SCT CONVECTION THURS NIGHT THRU MON AS SURFACE BOUNDARY DISSIPATES AND A RETURN TO NORMAL SEA BREEZE AFTN/EVE ACTIVITY. MIN TEMPS REMAIN CLOSE TO NORMAL (CLIMO AROUND 70) WITH MAX TEMPS BEGINNING EXTENDED IN UPPER 80S...A LITTLE BELOW CLIMO (CLIMO LOW 90S). THEY THEN RETURN TO CLIMO SAT AND INCH UP TO A TAD ABOVE CLIMO ON MON...ALLOWING FOR A PROGRESSIVELY STRONGER SEA BREEZE EACH AFTERNOON. && .AVIATION...DURING REST OF OVERNIGHT HOURS...SW-NE BAND OF CONVECTION HIGHLIGHTED BY EXCESSIVE LIGHTNING MOVING EWD AND WEAKENING THRU CWA TOWARDS SUNRISE. BAND ASSOCD WITH MVFR CIGS/VSBYS (AND BRIEF IFR CONDS) IN ANY HEAVY RAIN AND FOG. UNTIL BAND DIES OUT AND/OR EXITS E OF I-75...FORECAST REMAINS TRICKY. AFTER SUNRISE... EXPECT AN UNSETTLED DAY...WITH FAIRLY WIDESPREAD CONVECTION/RAIN EVENT AT THE TERMINALS AND THIS REFLECTED IN TAF WITH 4HR TEMPOS FOR TSTMS/MVFR CIGS/VSBYS UNTIL AT LEAST MID EVE. THE MAIN THREATS WITH ANY STRONGER STORMS WILL BE DAMAGING WIND GUSTS UP TO 40-60 MPH AND HAIL. SURFACE WINDS WILL REMAIN OUT OF THE WEST-SOUTHWEST THROUGH THIS EVE. && .MARINE...PROLONGED PERIOD OF WEST TO SW FLOW ON TAP. LOOKING FOR THE GRADIENT TO FURTHER TIGHTEN UP AS THE COLD FRONT SAGS SOUTHWARD TOWARD THE AREA. EXERCISE CAUTION CONDITIONS ARE EXPECTED TO BEGIN TODAY. THESE ELEVATED WINDS WILL CONTINUE INTO WEDNESDAY AFTER WHICH THE GRADIENT WILL WEAKEN. && .FIRE WEATHER...WITH COLD FRONT STALLING TO THE NORTH OVER THE NEXT FEW DAYS...MOIST SOUTHWEST FLOW OFF THE GULF COMBINED WITH SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL KEEP RELATIVE HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS THROUGH THE MID-WEEK PERIOD. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 86 73 86 72 89 / 90 60 70 50 60 PANAMA CITY 86 76 85 76 89 / 80 50 70 50 60 DOTHAN 85 72 87 72 93 / 90 50 60 30 40 ALBANY 87 74 90 71 93 / 90 60 60 30 40 VALDOSTA 88 73 87 71 90 / 90 60 70 40 60 CROSS CITY 86 75 84 72 88 / 70 60 70 50 60 APALACHICOLA 88 77 85 75 88 / 80 50 70 50 60 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...NONE. GM...NONE. && $$ SHORT TERM/MARINE...WATSON LONG TERM...BLOCK AVIATION/FIRE WEATHER...BLOCK