Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 310650
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
250 AM EDT FRI JUL 31 2015

.SHORT TERM...FRIDAY THROUGH SATURDAY...THE SEMI-PERMANENT...AT
LEAST THIS SUMMER...EAST COAST UPPER TROUGH AND QUASI-STATIONARY
FRONTAL BOUNDARY DRAPED ACROSS THE AREA WILL DOMINATE THE LOCAL
CONDITIONS DURING THE SHORT TERM. A SERIES OF FRONTAL WAVES WILL
MOVE ALONG THE FRONT WITH WIDESPREAD CONVECTION DEVELOPING OVER
LAND DURING THE AFTERNOON AND EVENING HOURS AND CONTINUING OVER
THE COASTAL WATERS OVERNIGHT. OVERALL THE BEST CHANCE FOR
CONVECTION WILL BE ALONG AND SOUTH OF INTERSTATE 10. THE SYNOPTIC
SOUTHWEST FLOW PATTERN WILL PIN THE EAST COAST SEA BREEZE FRONT
CLOSE TO THE COAST WITH THE CONVECTION INTERACTING WITH IT BETWEEN
18-22 LOCAL OVER THE COASTAL COUNTIES AS WELL AS CLAY AND PUTNAM.

HIGH TEMPERATURES WILL BE IN THE MID 90S OVER GEORGIA WITH HEAT
INDEX VALUES IN THE 100-105 DEGREE RANGE. HIGH TEMPERATURES OVER
FLORIDA WILL BE IN UPPER 80S TO LOWER 90S. AFTERNOON AND EARLY EVENING
CONVECTION IS EXPECTED TO BE WIDESPREAD TO NUMEROUS IN MOST AREAS
ON BOTH DAYS.

.LONG TERM (SAT NIGHT THROUGH THUR) TROUGH IS THE WORD OF THE WEEK
LOOKING INTO THE EXTENDED PORTION OF THE FORECAST PERIOD. THE
STALLED TROUGH WE HAVE HAD IMPACTING OUR WEATHER OVER THE LAST WEEK
APPEARS TO BE GOING NOWHERE THROUGH THE END OF THE FORECAST PERIOD.

ON SATURDAY THE UPPER LEVEL PATTERN SHOWS A BIG BLOCKING RIDGE OVER
THE DESERT SW WITH A LONGWAVE TROUGH OVER THE EASTERN THIRD OF THE
US. A SHORTWAVE IS EXITING THE LONGWAVE TROUGH OVER THE NE US WITH
AN ASSOCIATED WEAK FRONTAL BOUNDARY EXTENDING DOWN THE ATLANTIC
SEABOARD. BOTH THE GFS AND EURO KEEP A STATIONARY BOUNDARY WEST TO
EAST OVER THE STATE SPLITTING THE GAP BETWEEN THE WESTERN CONUS
RIDGE AND THE BERMUDA RIDGE. ROUNDS OF SHORTWAVES EVERY FEW DAYS
WILL RIDE OVER THE NORTHERN US...JUST CLOSE ENOUGH TO PROVIDE ENOUGH
UPPER LEVEL SUPPORT TO KEEP THE STATIONARY FRONT ALIVE WITHOUT
CAUSING ENOUGH CYCLOGENESIS TO SPIN UP A CONSOLIDATED CUT OFF LOW.

AS WAS THE CASE OVER THE LAST WEEK....GLOBAL MODELS HAVING A TOUGH
TIME HANDLING WHERE THE BEST LOCATION FOR ANY CYCLOGENESIS WILL BE
ALONG THE STATIONARY BOUNDARY AND HOW MUCH MID AND UPPER-LEVEL
ENERGY IS CARRIED NE BY EACH PASSING SHORTWAVE.

UNTIL THIS AREA OF LOWER PRESSURE CAN BE MOVED OUT OF THE AREA WE
WILL KEEP RAIN CHANCES IN THE 40-50 PERCENT RANGE DURING THE DAY
OVER THE LAND AREAS... WITH LATE NIGHT/EARLY MORNING CONVECTION OVER
THE WATERS. WITH CLOUDS..RAIN..AND A TROPICAL AIRMASS REMAINING IN
PLACE... EXPECT TEMPERATURES TO REMAIN NEAR CLIMO WITH LOW 90S FOR
HIGHS AND MID 70S FOR LOWS.

&&

.AVIATION...
MOIST AIR MASS AND LIGHT WINDS WILL LEAD TO LOCALLY DENSE FOG NEAR
DAYBREAK AT MOST FIELDS IN THE JACKSONVILLE AREA AND GAINESVILLE.
EXPECT WE WILL BRIEFLY DROP BELOW 1 MILE AT JAX INTL...CECIL
FIELD AND GAINESVILLE AROUND 12 UTC. SHOWERS OFFSHORE OF SAINT
SIMONS ISLAND MAY BRIEFLY MOVE OVER THE FIELD THROUGH 08 UTC.

CONVECTION IS EXPECTED TO DEVELOP IN THE GAINESVILLE AREA AROUND
15 UTC AND MOVE EASTWARD TOWARD THE COAST WERE IT WILL INTERACT
WITH THE ATLANTIC SEA BREEZE FRONT BETWEEN 20-24 UTC. LEFTOVER
CONVECTIVE DEBRIS MAY KEEP SOME LIGHT RAIN GOING OVER THE FLORIDA
FIELDS THROUGH 03-04 UTC. CONVECTION FIRING OVER THE SAVANNAH
RIVER AREA MAY SEND AN OUTFLOW BOUNDARY DOWN TOWARD SAINT SIMONS
THIS AFTERNOON KICKING OFF CONVECTION THERE. IN GENERAL CEILINGS
AT ALL OF THE FIELDS SHOULD BE BETWEEN 2-5 KFT IN STORMS.

&&

.MARINE...WITH A SYNOPTIC SOUTHWESTERLY FLOW PATTERN THE SEAS WILL
BE KEPT DOWN CLOSE TO THE COAST. NOCTURNAL WIND SURGES ALONG THE
PERIPHERY OF THE RIDGE MAY WARRANT SMALL CRAFT EXERCISE CAUTION
FOR WINDS OVERNIGHT ESPECIALLY OVER THE OFFSHORE AREAS.

RIP CURRENTS: LOW RISK ON FRIDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  93  74  92  74 /  50  60  50  30
SSI  86  76  86  75 /  50  50  50  50
JAX  90  74  87  75 /  50  50  50  50
SGJ  87  75  86  74 /  50  50  50  50
GNV  90  73  90  72 /  60  60  60  50
OCF  90  73  90  72 /  60  60  60  50

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&

$$

SANDRIK/WALSH



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