AFDTAE AREA FORECAST DISCUSSION...CORRECTED SPELLING NATIONAL WEATHER SERVICE TALLAHASSEE FL 407 AM EDT SAT JUL 30 2011 ...HEAT ADVISORY IN EFFECT FOR PORTIONS OF SOUTH CENTRAL GEORGIA AND THE SOUTHEAST BIG BEND OF FLORIDA THIS AFTERNOON... .SYNOPSIS... ABOVE AVERAGE TEMPERATURES AND HIGH HEAT INDICES WILL BE THE MAIN WEATHER STORY THROUGH THE WEEKEND. MAXIMUM HEAT INDICES ARE EXPECTED TO REACH 110 DEGREES ACROSS PORTIONS OF SOUTH CENTRAL GEORGIA AND THE SOUTHEAST BIG BEND OF FLORIDA THIS AFTERNOON AND A HEAT ADVISORY HAS BEEN ISSUED. ELSEWHERE...HEAT INDICES OF 104 TO 109 DEGREES ARE EXPECTED. RAIN CHANCES ARE EXPECTED TO SLOWLY RISE THROUGH THE SHORT TERM WITH TODAY BEING THE DRIEST DAY OVERALL ACROSS THE FORECAST AREA. && .SHORT TERM... (TODAY THROUGH MONDAY) MODELS AGREE THAT A STRONG UPPER LEVEL RIDGE WILL SHIFT WEST OF THE AREA THIS WEEKEND. A TYPE 8 SEA BREEZE REGIME IS EXPECTED TODAY (1000-700 MB MEAN WIND N/NW < 10 KNOTS) WHICH WILL RESULT IN THE SEA BREEZE HAVING A HARD TIME PENETRATING INLAND. THIS WILL ALLOW TEMPERATURES TO SOAR INTO THE UPPER 90S TO LOWER 100S OVER MOST INTERIOR LOCATIONS WITH THE HIGHEST THUNDERSTORM CHANCES ACROSS THE FLORIDA PANHANDLE AND BIG BEND FOR TODAY. THE CURRENT MAXIMUM HEAT INDEX FORECAST FOR TODAY DOES REACH 110 ACROSS PORTIONS OF THE EASTERN PART OF THE FORECAST AREA AND AFTER COORDINATION WITH THE JACKSONVILLE OFFICE HAVE ISSUED A HEAT ADVISORY IN THESE AREAS. FOR THE POP FORECAST...USED A BLEND OF THE MAV...MET...CONFIDENCE GRIDS...AND THE TYPE 8 SEA BREEZE CLIMATOLOGY GRID WITH EMPHASIS ON THE SPATIAL PATTERN OF THE TYPE 8 CLIMATOLOGY. ON SUNDAY...THE RIDGE IS FORECAST TO BE FAR ENOUGH WEST OF THE AREA TO ALLOW A WEAK UPPER LEVEL SHORTWAVE TO DROP SOUTH INTO THE AREA. THE SEA BREEZE REGIME WILL ALSO BE TRANSITIONING FROM A TYPE 8 TO MORE OF A TYPE 1 REGIME (LIGHT AND VARIABLE 1000-700 MB MEAN WIND) WHICH WILL ALLOW FOR A SOMEWHAT MORE UNIFORM CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. ON MONDAY...THE 1000-700 MB MEAN WIND LOOKS LIKE IT SHIFTS TOWARDS A SOUTHERLY DIRECTION WHICH WILL ALLOW THE AFTERNOON POP TO INCREASE SOMEWHAT AREAWIDE. .LONG TERM... (MONDAY NIGHT THROUGH NEXT SATURDAY) THE LARGE SCALE LONGWAVE PATTERN COMMENCES WITH PERSISTENT TROUGH FROM THE ERN PACIFIC INTO THE NW US WITH IMPULSES PROGRESSING EWD ALONG THE US/CANADIAN BORDER...AROUND THE PERIPHERY OF A EXPANSIVE RIDGE FROM WEST COAST EWD TO THE MID SOUTH...AND DROPPING INTO A NE US TROUGH. THIS TROUGH MARKED BY 557DM LOW OVER QUEBEC WITH AXIS EXTENDING SWD TO JUST OFF MID ATLC STATES THEN WSW TO JUST EAST OF FL. HIGH WILL BE FAR ENOUGH WWD TO ALLOW HEALTHY MID LEVEL ENERGY TO DROP SOUTHWARD INTO THE SOUTHEAST AND GULF COAST. AT SURFACE...LOW OFF VA/NC COAST WITH TRAILING FRONT SWWD TO CNTRL GA. BERMUDA HIGH PRESSURE FROM WRN ATLC CROSS CNTRL PENINSULA. THIS PLACES LOCAL AREA IN ONSHORE FLOW BETWEEN BOTH SYSTEMS AND AIDED BY H5 SHORTWAVES TO PROVIDE FOCUS FOR CONVECTION TO BEGIN THE WORK WEEK. MODELS ARE IN AGREEMENT THAT BY TUESDAY...H2 HIGH HAS RETREATED BACK TO SRN/CNTRL PLAINS WITH H5 ANCHORED OVER THE MID MISSISSIPPI VALLEY AND BOTH ARE EXPECTED TO PERSIST THERE. AT SAME TIME...A STRONG CANADIAN TROUGH MOVES ACROSS THE NRN TIER STATES GRADUALLY AMPLIFYING REACHING THE NERN STATES ON WED. IN RESPONSE... UPPER TROUGH DEEPENS ALONG AND JUST OFF NE/MID-ATLC SEABOARD AND DIGS DOWN THE EXTREME WRN ATLC WITH DRIER AIR EVENTUALLY WORKING ITS WAY SWWD AND ROTATING TOWARDS LOCAL AREA. ASSOCD WEAK VORT MAXES MAY ROTATE WWD FROM TROUGH THRU PERIOD AND PROVIDE BRIEF LIFT OF CONVECTION MOST DAYS. BY THURSDAY...TROUGH BASE ACROSS N/CNTRL FL BEGINS TO REVERT TO A CUTOFF LOW. LOW PROGGED BY GFS TO DRIFT ACROSS CNTRL FL AND THEN INTO GULF OF MEX ON FRI. AT SURFACE...AREA FRONT LINGERS FOR A FEW DAYS THEN DISSIPATES AS UPSTREAM HIGH PUSHES SEWD...AND BERMUDA HIGH SAGS SWD TO SRN FLORIDA PENINSULA BY MIDWEEK. BY WEEKEND...TROUGH WEAKENS AND THEN DISSIPATES AS PLAINS HIGH PRESSURE BUILDS BACK EWD TO OVER LOCAL REGION. WITH SHORTWAVES SLATED TO REMAIN WELL TO OUR N/W...PRECIPITATION WILL BE FOCUSED ALONG SEA BREEZE. FINALLY END OF PERIOD MAY BE MODIFIED BY POSSIBLE TROPICAL SYSTEM. PER NHC...KEEPING AN EYE ON LARGE LOW WELL EAST OF WINDWARD ISLANDS WITH FAVORABLE SHOT AT BECOMING TROPICAL CYCLONE AS IT MOVES WNW. WILL GO WITH LOW-MID SCT POPS MON NIGHT THRU TUES...LOW SCT POPS WED AND THURS AND WDLY SCT-SCT POPS FRI AND SAT. MIN AND TEMPS WILL REMAIN 2 TO 5 DEGREES ABOVE CLIMO THRU THE PERIOD. (AVG INLAND MAX/MIN TEMPS ARE 71/92 DEGREES). THE COMBINATION OF TEMPS IN THE MID 90S AND HIGH HUMIDITIES WILL ALLOW MAXIMUM HEAT INDICES WILL RISE TO 105 TO 109 TUES AND WED AFTN. WITH HUMIDITIES DROPPING TOWARD THE WEEKEND...MAX HEAT INDICES DROP TO AROUND 105 ON FRI AND 100 DEGREES ON SAT. && .AVIATION... WITH HIGH PRESSURE IN CONTROL...VFR CONDITIONS WILL PREVAIL THROUGH THE OVERNIGHT HOURS...WITH JUST SOME PATCHY MVFR VIS POSSIBLE AROUND SUNRISE. VFR CONDITIONS WILL THEN PREVAIL THROUGH 06Z SAT. THE ONLY EXCEPTIONS WILL BE BRIEF MVFR IN THE VICINITY OF THE TYPICAL WIDELY SCT AFTERNOON/EARLY EVENING SHOWERS AND STORMS. && .MARINE... THE SUBTROPICAL RIDGE WILL DOMINATE THE WEATHER ACROSS THE MARINE AREA WITH LOW WINDS AND SEAS EXPECTED FOR THE NEXT SEVERAL DAYS. && .FIRE WEATHER... DESPITE THE LOW RAIN CHANCES AND HOT TEMPERATURES...HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE CRITICAL VALUES THROUGH THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 98 76 98 77 94 / 30 20 50 40 50 PANAMA CITY 93 78 92 78 91 / 30 10 40 30 50 DOTHAN 98 76 97 76 95 / 20 10 40 30 50 ALBANY 100 75 99 77 95 / 20 10 50 40 50 VALDOSTA 101 75 100 77 94 / 20 20 50 40 50 CROSS CITY 97 76 94 75 92 / 30 30 50 40 50 APALACHICOLA 93 77 93 78 90 / 30 20 30 20 50 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM EDT THIS EVENING FOR THE FOLLOWING ZONES: BEN HILL...BERRIEN...BROOKS... COOK...IRWIN...LANIER...LOWNDES...TIFT...TURNER. FL...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM EDT THIS EVENING FOR THE FOLLOWING ZONES: INLAND TAYLOR...LAFAYETTE... MADISON. GM...NONE. && $$