AFDJAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 420 AM EDT FRI JUL 29 2011 .SHORT TERM...TODAY THROUGH SUNDAY MID TO UPPER LEVEL HIGH WILL SLOWLY MOVE WEST ACROSS THE CWA TODAY. STRONG SUBSIDENCE AND DRY AIR ALOFT WILL MOSTLY INHIBIT ANY THUNDERSTORMS THAT ATTEMPT TO INITIATE ALONG THE SEABREEZES. POPS WILL REMAIN CAPPED AT 30 PERCENT AND MAINLY CONFINED TO INTERIOR PORTIONS OF NE FL WHERE THE SEABREEZES ARE MOST LIKELY TO COME TOGETHER. TEMPERATURES WILL TOP OUT IN THE MID TO UPPER 90S ACROSS ALL INLAND AREAS. HEAT INDICES WILL TOP OUT BETWEEN 105 AND 110 DEGREES...JUST BELOW HEAT ADVISORY CRITERIA. NE FLORIDA BEACHES AND ADJACENT COMMUNITIES WILL GET EARLY RELIEF FROM THE SEABREEZE WITH TEMPS ONLY MAXING OUT IN THE LOW 90S. A SURFACE TROUGH ALONG THE EASTERN SEABOARD WILL ELONGATE INTO NORTHERN PORTIONS OF THE AREA THIS AFTERNOON WHICH WILL KEEP THE EAST COAST SEABREEZE CLOSER TO THE COAST IN SOUTHEAST GEORGIA. THE HEAT WILL TURN UP A NOTCH ON SATURDAY AS 850 MB TEMPS INCREASE A COUPLE OF DEGREES. UPPER 90S WILL BE COMMON AWAY FROM THE BEACHES...BUT EVEN THE BEACHES ARE LIKELY TO TOP OUT IN THE MID 90S SINCE THE SEABREEZE WILL BE SLOW TO MOVE INLAND DUE TO THE SURFACE TROUGH STRETCHING SOUTH INTO NORTHERN FLORIDA. IF THE FORECAST HIGHS ARE REALIZED THEN HEAT INDICES WILL LIKELY REACH 110 DEGREES ALONG AND NORTH OF INTERSTATE 10. THE ONLY POSSIBLE KINK IN THIS FORECAST WOULD COME FROM MORE THAN EXPECTED CLOUDS AND PRECIP IN ASSOCIATION WITH INCREASED CONVERGENCE ALONG THE AFOREMENTIONED SURFACE TROUGH. THE CURRENT THINKING THOUGH GIVES MORE PRECEDENCE TO SUBSIDENCE AND DRY AIR ALOFT...SUPPORTING POPS LESS THAN CLIMATOLOGICAL VALUES. THE NAM CLOSES OFF THE SURFACE TROUGH OVER SE GA ON SUNDAY AND THEN MOVES IT SOUTHWEST INTO THE GULF OF MEXICO. THE GFS ALSO CLOSES IT OFF BUT PLACES IT FARTHER NORTHWEST THAN THE NAM. THE NAM ALSO INDICATES STRONG SHORTWAVE TROUGHING DROPPING SOUTH INTO THE AREA AROUND THE EASTERN PERIPHERY OF THE WESTWARD RETREATING UPPER HIGH. THIS ENHANCED UPPER FORCING WOULD SUPPORT NUMEROUS THUNDERSTORM ACTIVITY ON SUNDAY. POPS HAVE BEEN INCREASED TO 60 PERCENT ACROSS MOST OF THE WESTERN TWO THIRDS OF THE AREA...AS THE EAST COAST SEABREEZE SHOULD PUSH INLAND EARLY ENOUGH TO KEEP THUNDERSTORMS MORE ISOLATED TO SCATTERED OVER THE EASTERN THIRD OF THE AREA. .LONG TERM...MONDAY THROUGH THURSDAY THE GFS DROPS A POTENT SHORTWAVE DOWN THE EAST COAST ON MONDAY...SUPPORTIVE OF ABOVE NORMAL CHANCES OF THUNDERSTORMS. TEMPERATURES WILL DROP BACK SOME BUT REMAIN ABOVE NORMAL. FOR THE REST OF THE WEEK...THE FORECAST AREA WILL FIND ITSELF BETWEEN THE STRONG UPPER HIGH OVER THE SOUTHERN PLAINS AND AN ANOMALOUS TROUGH OVER THE WESTERN ATLANTIC. THIS WILL TRANSLATE TO AT OR BELOW NORMAL POPS AND AT OR ABOVE NORMAL TEMPS. && .AVIATION...WILL ADD CB FOR AFTN AT GNV BUT SINCE TSRA CHANCES ARE LOW...WILL NOT INCLUDE TS WITH 12Z TAFS. VFR WILL PREVAIL. && .MARINE...NO HEADLINES. SEAS ARE RUNNING 2-3 FT WITH S TO SW WINDS LESS THAN 10 KT. WINDS WILL BE LIGHT TO DAY THEN SLY FLOW INCREASES OVER THE WEEKEND AS TROUGH DRIFTS INTO THE SOUTHEAST STATES AND HIGH PRESSURE DRIFTS OFFSHORE. && .PRELIMINARY POINT TEMPS/POPS... AMG 98 74 100 75 / 20 10 30 20 SSI 93 77 95 78 / 20 10 20 10 JAX 93 74 98 76 / 30 10 30 10 SGJ 90 74 93 76 / 20 10 20 10 GNV 97 73 98 73 / 30 10 40 20 OCF 96 73 96 74 / 30 10 30 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$