000 FXUS62 KTAE 130801 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 401 AM EDT TUE MAY 13 2008 .SYNOPSIS... THE 05 UTC REGIONAL SURFACE ANALYSIS SHOWED 1016 MB HIGH CENTERED AT DOTHAN AL. VAPOR IMAGERY SHOWED A RIDGE AXIS FROM THE WESTERN GULF COAST UP THROUGH THE WESTERN GREAT LAKES...AND DEEP TROUGHS ON EITHER SIDE OF THE RIDGE. THE UPPER AIR PATTERN HAS SLOWED DOWN CONSIDERABLY SINCE LAST WEEK AS IT HAS BECOME MUCH MORE AMPLIFIED. && .SHORT TERM... (TODAY THROUGH THURSDAY) THERE IS GOOD AGREEMENT AMONG THE 00 UTC GFS/NAM AND 12 UTC MONDAY ECMWF IN SHIFTING THE 500 MB RIDGE EASTWARD TO A POSITION OVER THE SOUTHEAST U.S. BY WEDNESDAY...AS THE SURFACE RIDGE PROPAGATES EASTWARD OFF THE SOUTHEAST U.S. COAST. THERE WILL BE A LACK OF LARGE SCALE Q-G FORCING AND INSTABILITY IN OUR REGION THROUGH WEDNESDAY...SO FAIR WEATHER WILL CONTINUE. TEMPERATURES WILL QUICKLY REBOUND TO NEAR AVERAGE LEVELS THIS AFTERNOON AFTER A RELATIVELY COOL START THIS MORNING. THE NEXT CHANCE OF RAIN WILL BEGIN THURSDAY AFTERNOON AS AS THE 500 MB RIDGE BUCKLES A BIT WHEN A PIECE OF THE WESTERN CONUS TROUGH SHEARS OUT TO THE NORTHEAST OVER THE OHIO VALLEY. AS THIS OCCURS A COLD FRONT WILL DRAW CLOSER TO OUR AREA...WITH THE HIGHEST POP AROUND 40 PERCENT IN OUR SOUTHEAST AL ZONES...NEAREST THE FRONTAL SYSTEM. TEMPERATURES WILL REMAIN NEAR AVERAGE THROUGH THE PERIOD. .LONG TERM... (FRIDAY-TUESDAY)...HAVE MORE CONFIDENCE NOW IN THE MEDIUM RANGE PERIOD AS BOTH THE GFS AND EURO ARE IN AGREEMENT WITH THE TIMING OF THE NEXT COLD FRONTAL PASSAGE (FRIDAY AND FRIDAY NIGHT). THE FRONT WILL BE PRECEDED BY SHWRS/TSTMS (COVERAGE 40-50 PERCENT). MODELS CONTINUE TO DEPICT STRONG WLY FLOW ALOFT WITH FAVORABLE THERMODYNAMICS TO SUPPORT SOME STRONG TO SEVERE TSTMS OVER THE SERN STATES. AFTER THE FRONTAL PASSAGE, SURFACE HIGH PRESSURE WILL RIDGE ACROSS THE GULF COAST STATES FOR SATURDAY AND SUNDAY WITH DRIER AIR AND SLIGHTLY BELOW CLIMO TEMPS. THE OVERALL PATTERN ALOFT WILL BE CHARACTERIZED BY A LONG WAVE TROUGH OVER THE ERN HALF OF THE LOWER 48 INTO EARLY NEXT WEEK. BOTH THE GFS AND EURO SHOW DISTURBANCES IN THE NWLY FLOW ALOFT, WITH A SERIES OF WEAK FRONTS MOVING SWD ALONG THE EAST COAST MONDAY AND TUESDAY. MOISTURE LOOKS MARGINAL AT BEST AND MAINLY CONFINED TO OUR ERN ZONES, SO WILL KEEP POPS CAPPED AT 20 PERCENT FOR THESE AREAS. TEMPS WILL MODERATE BACK TO CLIMO VALUES. && .AVIATION... EXPECT VFR WITH OCNL CIRRUS THROUGHOUT THE TAF PERIOD. WINDS WILL BE ELY 5-10 KTS DURING THE DAY, WITH THE EXCEPTION OF KTLH AND KPFN WHERE WINDS BECOME SLY NEAR 10 KTS WITH THE AFTERNOON SEA BREEZE. && .MARINE... WINDS AND SEAS WILL BE QUITE LOW TODAY DUE TO THE LACK OF A SUBSTANTIAL PRESSURE GRADIENT. AS THE RIDGE MOVES EAST OF OUR AREA TONIGHT...THE MODELS FORECAST AN EASTERLY SURGE DEVELOPING AFTER MIDNIGHT...POSSIBLY FLIRTING WITH CAUTION LEVELS THROUGH TOMORROW MORNING. && .FIRE WEATHER... RED FLAG CONDITIONS ARE EXPECTED FOR ALL FL ZONES TODAY, EXCEPT THE IMMEDIATE COAST, DUE TO LONG DURATIONS OF SUB-35 PERCENT RH. DESPITE SUB-30 PERCENT RH VALUES ACROSS THE AL AND GA ZONES, THE WIND AND KBDI REQUIREMENTS WILL NOT BE MET. ON WEDNESDAY, CRITICAL DURATIONS OF SUB-35 PERCENT RH WILL BE POSSIBLE FOR THE ERN FL BIG BEND ZONES BORDERING THE SUWANNEE VALLEY, AND HAVE ISSUED A WATCH. NO CONCERNS FOR THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 86 57 85 62 88 / 0 0 0 10 20 PANAMA CITY 84 65 84 69 84 / 0 0 10 10 30 DOTHAN 86 60 85 65 85 / 0 0 10 10 40 ALBANY 83 58 83 63 87 / 0 0 10 10 30 VALDOSTA 83 55 85 61 87 / 0 0 10 10 20 CROSS CITY 86 54 86 61 86 / 0 0 0 10 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING FROM 1 PM EDT /NOON CDT/ THIS AFTERNOON TO 8 PM EDT /7 PM CDT/ THIS EVENING FOR THE FOLLOWING ZONES: BAY... CALHOUN...DIXIE...FRANKLIN...GADSDEN...GULF...HOLMES... INLAND WALTON...JACKSON...JEFFERSON...LAFAYETTE...LEON... LIBERTY...MADISON...TAYLOR...WAKULLA...WASHINGTON. FIRE WEATHER WATCH WEDNESDAY AFTERNOON FOR THE FOLLOWING ZONES: DIXIE...LAFAYETTE...MADISON...TAYLOR. GM...NONE. && $$ AVIATION/LONG TERM/FIRE WEATHER...JAMSKI REST OF DISCUSSION...FOURNIER