259
FXUS62 KJAX 051840
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
240 PM EDT SUN JUL 5 2009
SHORT TERM (TONIGHT-WED)
TONIGHT WILL BE TRANSITION PERIOD
AS DRY PATTERN OVER THE AREA PAST SEVERAL DAYS WILL BE COMING
TO AN END BEGINNING MONDAY. THE MEAN LAYER RIDGE (1000-500MB)
HAS SHIFTED WELL SOUTH OF THE AREA AND WILL CONTINUE TO SHIFT
SOUTH AND WEAKEN AS A BROAD TROUGH DEVELOPS ACROSS THE REGION
NEXT WEEK. WESTERLY FLOW SHOULD STILL BE LIGHT ENOUGH OVER THE AREA
TO HAVE A SEA BREEZE COLLISION NEAR THE COAST LATE THIS AFTERNOON
AND EVE AND MAY SEE A FEW ISOLATED STORMS ALONG THE COLLISION. 12Z
SOUNDINGS CAME IN MORE MOIST AND UNSTABLE WITH MODIFIED CAPES AROUND
3000J SO ANY STORMS THAT GET GOING WILL BE STRONG. COLD FRONT TO THE
NW EDGES SE TONIGHT MAKING IT INTO EXTREME N GA 12Z MON AND THEN
STALLING JUST NORTH OF THE AREA REST OF NEXT WEEK. SPC HAS THE NW
CORNER OF FORECAST AREA UNDER SLIGHT RISK LATE TODAY AND TONIGHT.
AS COLD FRONT EDGES SE TONIGHT...MAY SEE A FEW STORMS PROPAGATE INTO
THE NW ZONES SOME OF WHICH MAY BE SEVERE WITH WET MICROBURST
POTENTIAL. HAVE HIGHEST POPS TONIGHT FOR THE NW ZONES WITH ISOLATED
POPS ELSEWHERE. AS BROAD TROUGH DEVELOPS OVER THE REGION...FRONT
STALLS JUST NORTH OF THE AREA RESULTING IN A DEEPENING SOUTHWEST
FLOW OFF THE GULF OF MEXICO WHICH WILL SUSTAIN HIGH MOISTURE LEVELS
AND INTERACT WITH THE HEIGHT FALLS AND IMPULSES. THE MAIN FORECAST
CONCERN THROUGH THE SHORT TERM WILL BE HEAVY RAINFALL POTENTIAL ON
MON-WED AS THE DEEPENING SOUTHWEST FLOW REGIME WILL LIKELY LEAD TO
TRAINING OF SHOWERS AND STORMS.
LONG TERM (WEDNESDAY THROUGH SATURDAY)
NO MAJOR CHANGES WERE
MADE TO THE EXTENDED. HIGH ATMOSPHERIC MOISTURE CONTINUING TO RESIDE
ACROSS THE AREA ALONG WITH OLD FRONTAL BOUNDARY MEANDERING NEAR THE
AREA. RAIN CHANCES ARE FORECAST TO DECREASE THURSDAY ONWARD AS
FRONTAL BOUNDARY IS FORECAST TO DISSIPATE AND UPPER LEVEL RIDGE
BUILDS INTO THE FROM THE WEST.
AVIATION
VFR CONDS CONTINUE THIS AFTERNOON WITH SCT CU FIELD DECK AROUND
4-5KFT WITH ABUNDANT CIRRUS ABOVE. HAVE INCLUDED CB MENTION AT TAF
SITES WITH THE ISOLD TSTM POSSIBILITY THAT REMAINS THROUGH 03Z.
AFTER 03Z STILL SOME UNCERTAINTY WHETHER WESTERLIES WILL PUSH TSTM
ACTIVITY INTO THE TAF SITES OR JUST SOME WEAKENING SHOWER ACTIVITY
AND FOR NOW HAVE JUST INCLUDED VCSH AT TAF SITES ALONG WITH TEMPO
GROUPS AFTER 06Z FOR SOME IFR CIGS AS MOIST SWLY FLOW OFF THE NERN
GOMEX WILL PROVIDE CONDS FOR SOME STRATUS DEVELOPMENT. MORE ABUNDANT
TSTM ACTIVITY WILL COMMENCE ARND 15Z MON AND HAVE PLACED VCTS BUT
WILL LIKELY NEED TO BE MORE AGGRESSIVE IN LATER PACKAGES.
MARINE
SOUTHWEST WINDS WILL BE ON THE INCREASE OVER THE NEXT 24 HOURS AS
THE COLD FRONT OVER THE SERN U.S. APPROACHES THE REGION. HAVE POSTED
A SMALL CRAFT EXERCISE CAUTION FOR TONIGHT OVER THE OFFSHORE WATERS.
THE LATEST 09Z SREF AND 12 GFS/NAM IN FAIR AGREEMENT THAT A PERIOD
OF CLOSE TO SWLY 20 KNOT WINDS ARE IN STORE FOR THE OFFSHORE WATERS
FROM MONDAY NIGHT INTO TUESDAY NIGHT...STRONGEST DURING THE
NOCTURNAL SURGES. WINDS WILL SLOWLY DECREASE FROM WEDNESDAY THROUGH
THE END OF THE WEEK AS THE FRONT SAGS INTO THE WATERS AND WASHES OUT.
STRONG GUSTY WINDS WILL ACCOMPANY THE NUMEROUS TO WIDESPREAD
THUNDERSTORM ACTIVITY EACH DAY AND BOATERS SHOULD BE PREPARED FOR
MULTIPLE SPECIAL MARINE WARNINGS TO BE ISSUED.
PRELIMINARY POINT TEMPS/POPS
AMG 74 88 71 89 / 40 70 50 50
SSI 76 88 74 87 / 30 70 50 60
JAX 74 90 73 89 / 20 70 60 70
SGJ 76 90 74 88 / 20 60 50 70
GNV 74 89 73 89 / 20 60 60 70
OCF 74 88 72 88 / 20 60 40 70
JAX WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GA...NONE.
AM...NONE.
PP/JH/PK
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