AFDMOB AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MOBILE AL 1140 AM CDT THU AUG 25 2011 .AVIATION [18Z TAF ISSUANCE]...VFR CONDITIONS. LIGHT NORTHERLY WIND BECOMES SOUTHEAST TO SOUTHEAST LATE AFTERNOON. A FEW ISOLATED THUNDERSTORMS...VERY SHORT LIVED...WILL BE POSSIBLE MAINLY NEAR THE AL AND MS COAST THIS AFTERNOON. /10 && .UPDATED...UPPER AIR DATA ANALYSIS THIS MORNING SHOWS A HIGH LEVEL DISTURBANCE SINKING SOUTHWARD ACROSS LOUISIANA AND SOUTHERN MISSISSIPPI WITH WATER VAPOR SATELLITE IMAGERY AND SOUNDING DATA SHOWING BEST MOISTURE OVER THE SOUTHWEST ZONES EARLY ON. THERE IS A TREND NOTED IN WATER VAPOR LOOPS...FOR THE DEEP LAYER ENVIRONMENT TO DRY OUT THROUGH THE DAY...THUS ACTING TO LIMIT COVERAGES OF STORMS FOR MUCH OF THE AREA. THE EXCEPTION BEING THE GULF COAST AND INTERIOR SOUTHEAST MISSISSIPPI. FORECASTERS HAVE MODIFIED TEMPERATURE/DEWPOINT PROFILES FOR MOBILE THIS AFTERNOON USING A TEMPERATURE OF 96 AND A DEWPOINT MIXED OUT TO 67. THIS YIELDS INSTABILITY TO 1000-1500 J/KG...BUT WITH PRECIPITABLE WATERS ROUGHLY A THIRD LOWER THAN SEEN ON WEDNESDAY...WILL MAINTAIN ISOLATED COVERAGES FOR THE GULF COAST AND SOUTHEAST MISSISSIPPI. COULD SEE A FEW DEVELOP ELSEWHERE...BUT WHEN UPDRAFTS HIT THE DRIER AIR UP THERE...SHOULDN`T LAST LONG THEREAFTER. /10 THE UPDATED WET MICROBURST RISK ASSESSMENT FOR TODAY IS LOW. /PREVIOUS DISCUSSION / 527 AM CDT THU AUG 25 2011 ...NEAR RECORD HEAT EXPECTED FOR THE END OF THIS WEEK... .SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...A WEAK SFC TROF OF LOW PRESSURE OVER WESTERN AND LOWER PARTS OF THE CWFA WILL SHIFT WEST TODAY AS HIGH PRESSURE STRENGTHENS FROM THE NORTH NORTHEAST MOSTLY IN RESPONSE TO HURRICANE IRENE MOVING NORTHWARD OVER THE WESTERN ATLANTIC. LATEST MODEL SOUNDINGS DEPICT AN EVEN DRIER SCENARIO TODAY WITH PW`S DROPPING TO BELOW 1.20 INCHES OVER THE EASTERN AND NORTHERN SECTIONS OF THE CWFA...AND AROUND 1.4 INCHES OVER WESTERN AND COASTAL SECTIONS. DEWPT TEMPERATURES ALSO DROP TO THE LOWER 60S TO THE EAST...AND THE MID TO UPPER 60S TO THE WEST AND ALONG THE COAST WITH MOSTLY A NORTHEAST TO EASTERLY FLOW...EXCEPT NEAR THE IMMEDIATE COAST WHERE A WEAK ONSHORE FLOW DEVELOPS FROM AFTERNOON HEATING. WITH THIS...WILL LIKELY SEE A FEW ISOLATED THUNDERSTORMS AGAIN TODAY NEAR THE SEABREEZE CIRCULATION...MAINLY TO THE WEST AND ALONG THE IMMEDIATE COAST WITH MUCH LESS INTENSITY DUE TO LIMITED INSTABILITY AND CAPPING IN THE MID LEVELS. WITH PLENTY OF DRY AIR ALOFT AND DRIER AIR ADVECTING SOUTHWARD NEAR THE SFC BELIEVE ANY CONVECTION THAT DOES DEVELOP WILL BE VERY SHORT LIVED. AS FOR HIGH TEMPS THIS AFTERNOON WILL LEAN TOWARDS THE WARMER MET GUIDANCE DUE TO BETTER SUBSIDENCE IN THE MID LEVELS AND PERSISTENCE. FOR LOWS TONIGHT WILL USE A BLEND OF THE MAV AND MET MOSTLY DUE TO THE WARMER TEMPS LINGERING INTO THE EARLY EVENING HOURS. DEEP NORTHERLY FLOW WILL BE IN PLACE ON FRIDAY BETWEEN THE UPPER RIDGE OVER THE FOUR CORNERS AND THE LARGE CIRCULATION OF HURRICANE IRENE EAT OF THE GA/SC COAST. IN ADDITION...A SUBTLE SHORTWAVE IS FORECAST TO DIVE SOUTH OUT OF THE OHIO VALLEY AND INTO THE SOUTHEAST LATE FRIDAY AFTERNOON INTO FRIDAY NIGHT. THIS WILL SEND A FRONTAL BOUNDARY INTO OUR AREA LATE FRIDAY WHICH PUSHES OFFSHORE BY SATURDAY MORNING. AHEAD OF THIS BOUNDARY...1000-850 MB THICKNESSES ARE FORECAST TO RISE TO NEAR 1450 M FRI AFTN IN RESPONSE TO 850MB TEMPS CLIMBING TO 22-23C. WE HAVE ALREADY SEEN HIGHS OF 100 DEGREES OVER SEVERAL LOCATIONS THIS WEEK WITH LOW LEVEL THICKNESS VALUES 10-15M LOWER THAN WHAT IS FORECAST FOR FRIDAY. THEREFORE...WILL GO ON THE HIGH SIDE OF GUIDANCE (AND IN SOME CASES ABOVE GUIDANCE) SHOWING HIGHS NEAR 100 FOR THE MAJORITY OF THE AREA. EVEN COASTAL AREAS ARE EXPECTED TO CLIMB INTO THE UPPER 90S AS THE DEEP LAYER NORTHERLY FLOW PREVENTS INLAND PROGRESSION OF THE SEA BREEZE. THESE TEMPERATURES ARE AT OR NEAR RECORD LEVELS FOR THE AREA (SEE CLIMATE SECTION BELOW). PRECIPITABLE WATERS ARE EXPECTED TO DROP TO AROUND 1.25 INCHES ON AVERAGE...WHICH WILL HELP DEWPOINTS MIX OUT INTO THE 60S AND LIKELY KEEP HEAT INDICES BELOW ADVISORY LEVELS...ALTHOUGH HEAT INDICES OF 105-108 ARE STILL POSSIBLE...ESPECIALLY ALONG THE COASTAL ZONES WHERE DEWPOINTS WILL REMAIN A LITTLE HIGHER. THE DRY ATMOSPHERIC COLUMN AND SUBSIDENCE ON THE WEST SIDE OF IRENE`S CIRCULATION SHOULD RESULT IN A DRY DAY FRIDAY WITH CHANCES OF CONVECTION 10% OR LESS. DEWPOINTS IN THE 60S SHOULD PERSIST FRIDAY NIGHT AS THE FRONT PUSHES THROUGH... CUTTING DOWN ON HUMIDITY LEVELS. LOWS STILL VERY MILD IN THE LOW TO MID 70S...WITH NEAR 80 AT THE BEACHES. 34/JFB && .LONG TERM (SATURDAY THROUGH WEDNESDAY)...A SERIES OF SHORTWAVE TROUGHS DIVING SOUTH AROUND THE WESTERN RIDGE ALONG WITH HURRICANE IRENE MOVING UP THE EAST COAST WILL REINFORCE THE MID AND UPPER LEVEL TROUGHING OVER THE EASTERN STATES. FOR OUR AREA THIS TRANSLATES INTO A CONTINUED DEEP NORTHERLY FLOW WITH PRECIPITABLE WATERS DROPPING TO WELL BELOW ONE INCH SATURDAY THROUGH MONDAY (AROUND 50% OF NORMAL FOR LATE AUGUST). THIS WILL KEEP RAIN CHANCES NIL WITH A CONTINUATION OF ABOVE NORMAL HIGH TEMPERATURES...MID TO UPPER 90S SATURDAY WITH MID 90S SUN/MON. FORECAST DEWPOINTS IN THE UPPER 50S AND LOWER 60S WILL SERVE TO KEEP HEAT INDICES IN CHECK DURING THE AFTERNOON AND MAKE FOR MORE COMFORTABLE NIGHTS. LOWS WILL DROP SLIGHTLY BELOW NORMAL NORMAL FOR MUCH OF THE AREA...WITH MID 60S COMMON WELL INLAND TO LOWER 70S CLOSER TO THE COAST. AFTER ANOTHER DRY DAY TUESDAY...WEDNESDAY WILL SEE A RETURN TO MORE TYPICAL LATE SUMMER HUMIDITY LEVELS AS A BROAD MID LEVEL RIDGE BUILDS ACROSS THE SOUTHERN U.S. AND WESTERN ATLANTIC. A DEVELOPING SOUTHEAST LOW TO MID LEVEL FLOW WILL MARK THE RETURN OF SLIGHT CHANCE POPS BY WEDNESDAY AFTERNOON. 34/JFB && .MARINE...WEAK HIGH PRESSURE OVER THE NORTH CENTRAL GULF WILL GRADUALLY STRENGTHEN THROUGH EARLY NEXT WEEK AS HIGH PRESSURE BUILDS OVER THE NORTH CENTRAL GULF. A LIGHT ONSHORE FLOW WILL BECOME MOSTLY NORTH AND BUILD OVER THE WEEKEND AND INTO EARLY NEXT WITH THIS PATTERN. SEAS UP TO 3 FEET MOSTLY DURING THE EARLY MORNING HOURS CAN BE EXPECTED SAT THROUGH MON. 32/EE && .FIRE WEATHER...NORTH TO NORTHEAST LOW LEVEL FLOW WILL CONTINUE TO BRING DRIER AIR INTO THE REGION THROUGH THE END OF THE WEEK. THIS HAS RESULTED IN FORECAST DEWPOINTS DROPPING INTO THE LOW TO MID 60S AWAY FROM THE COAST WHILE HIGH TEMPERATURES SOAR INTO THE UPPER 90S TO NEAR 100. THEREFORE...RH LEVELS WILL DROP TO OR SLIGHTLY BELOW 35 PERCENT BOTH THIS AFTERNOON AND FRIDAY AFTERNOON. IN ADDITION...VERY DEEP MIXING HEIGHTS WILL YIELD AFTERNOON DISPERSIONS ABOVE 75 DURING THE SAME TIME FRAME. THEREFORE...A RED FLAG WARNING HAS BEEN ISSUED FOR THE INTERIOR FLORIDA PANHANDLE TODAY AND A FIRE WEATHER WATCH FOR FRIDAY. HEADLINE CRITERIA WILL NOT BE MET FOR MISSISSIPPI OR ALABAMA. 34/JFB && .CLIMATE...HERE ARE THE RECORD HIGHS FOR MOBILE AND PENSACOLA FOR THE NEXT FEW DAYS. MOBILE PENSACOLA AUGUST 25TH 100 (1938) 98 (1983) AUGUST 26TH 100 (1938,2000) 96 (1989,2000) AUGUST 27TH 97 (2000) 97 (1989,1998) && .PRELIMINARY POINT TEMPS/POPS... MOBILE 97 73 100 75 / 20 05 10 05 PENSACOLA 96 77 99 79 / 20 05 10 10 DESTIN 94 80 95 80 / 05 05 10 10 EVERGREEN 98 70 101 72 / 05 05 05 05 WAYNESBORO 98 73 100 71 / 05 05 05 00 CAMDEN 100 70 99 70 / 05 05 05 05 CRESTVIEW 98 71 100 75 / 05 05 10 05 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...NONE. FL...RED FLAG WARNING FROM 1 PM THURSDAY TO 6 PM THURSDAY FOR THE FOLLOWING ZONES: INLAND ESCAMBIA...INLAND OKALOOSA...AND INLAND SANTA ROSA. FIRE WEATHER WATCH FROM 1 PM FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: INLAND ESCAMBIA...INLAND OKALOOSA...AND INLAND SANTA ROSA. MS...NONE. GM...NONE. && $$