Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 310851
AFDJAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
451 AM EDT THU JUL 31 2014

.CURRENTLY...
OVERNIGHT SURFACE ANALYSIS DEPICTS SURFACE TROUGHING OVER
SOUTHEAST GA AND COASTAL NORTHEAST FL...WHILE A WEAKENING FRONTAL
BOUNDARY BISECTS THE FL PENINSULA. ALOFT...LONGWAVE TROUGHING
REMAINS ANCHORED FROM HUDSON BAY CANADA SOUTHWARD TO THE GULF
COAST AND NORTH FL...WITH AN EMBEDDED SHORTWAVE MOVING
SOUTHEASTWARD INTO THE ARKLATEX REGION. PATCHES OF LOW CUMULUS
AND ISOLATED SHOWERS EXTEND FROM THE OFFSHORE GA COASTAL WATERS TO
THE ALTAMAHA RIVER BASIN...WITH ACTIVITY GENERALLY MOVING WEST-
NORTHWESTWARD. OTHERWISE...FAIR SKIES AND LIGHT WINDS HAVE ALLOWED
TEMPERATURES TO FALL INTO THE MID 60S OVER PORTIONS OF THE
SUWANNEE VALLEY...WITH TEMPERATURES ELSEWHERE GENERALLY IN THE
LOWER 70S...EXCEPT UPPER 70S ALONG THE IMMEDIATE COAST.

.SHORT TERM (TODAY THROUGH SATURDAY NIGHT)...
SURFACE TROUGHING WILL REMAIN IN PLACE OVER SOUTHEAST GA AND THE
FL PENINSULA...WHILE A SUBSIDENT AIR MASS LINGERS OVER INTERIOR
LOCATIONS OF NORTHEAST AND NORTH CENTRAL FL. WEAK ISENTROPIC LIFT
ALONG THE TROUGH AXIS WILL KEEP THE THREAT FOR ISOLATED SHOWERS
AND THUNDERSTORMS IN PLACE...WITH ACTIVITY POSSIBLY BEING
ENHANCED ALONG THE COAST THIS AFTERNOON AS THE ATLANTIC SEA BREEZE
PUSHES INLAND TOWARDS THE I-95 CORRIDOR IN SOUTHEAST GA. HI-RES
SHORT TERM MODELS HAVE BEEN TOO BULLISH WITH RAINFALL
COVERAGE...AND THUS KEPT ISOLATED POPS IN THE FORECAST GRIDS
THROUGH MIDNIGHT. MEANWHILE...WE ARE NOT EXPECTING CONVECTIVE
COVERAGE TO INITIATE OVER NORTHEAST FL UNTIL THE AFTERNOON HOURS
UNTIL THE ATLANTIC SEA BREEZE MOVES ONSHORE...WITH WIDELY
SCATTERED ACTIVITY POSSIBLE OVER FLAGLER COUNTY DUE TO THEIR
PROXIMITY TO THE STALLED FRONTAL BOUNDARY AND SLIGHTLY DEEPER
MOISTURE VALUES. OTHERWISE...MODEL SOUNDINGS DEPICT BELOW SEASONAL
PWAT VALUES CONTINUING TODAY...AND THUS ONLY ISOLATED DIURNAL
CONVECTIVE ACTIVITY IS EXPECTED FOR THE REST OF NORTHEAST FL.
PLENTY OF INSOLATION AND A LINGERING DRY AIR MASS WILL AGAIN
BOOST HIGHS INTO THE MID 90S INLAND...WITH MAXIMUM HEAT INDICES
AROUND 100. AN EARLY AFTERNOON SEA BREEZE WILL KEEP HIGHS IN THE
UPPER 80S AT THE BEACHES.

SHORTWAVE TROUGHING MOVING INTO OUR REGION FROM THE WEST AFTER
MIDNIGHT TONIGHT IS EXPECTED TO ENHANCE CONVECTIVE DEVELOPMENT
ALONG AND EAST OF THE SURFACE TROUGH...WITH THE COASTAL WATERS
BEING FAVORED. WIDELY SCATTERED COVERAGE WILL BE POSSIBLE ALONG
THE SOUTHEAST GA COAST AND EXTENDING INLAND TO THE ALTAMAHA
RIVER...WITH ISOLATED ACTIVITY POSSIBLE FOR THE I-95 CORRIDOR.
OTHERWISE...LIGHT WINDS WILL ALLOW FOR SOME RADIATIONAL COOLING
ONCE AGAIN IN THE SUWANNEE VALLEY...WHERE LOWS WILL FALL TO THE
UPPER 60S. LOWS ELSEWHERE WILL GENERALLY FALL TO THE LOWER
70S...EXCEPT UPPER 70S AT THE COAST.

.FRIDAY THROUGH SATURDAY NIGHT...UPPER TROUGH BECOMES MORE DEFINED
ON FRIDAY AND SATURDAY WITH DEEP LAYER MOISTURE ON THE RISE
BRINGING BACK A MORE SEASONAL PATTERN OF SCATTERED AFTERNOON
SHOWERS AND THUNDERSTORMS. EXPECT CONVECTION TO INITIATE ON THE
SEA BREEZE DURING THE EARLY AFTERNOON AND CONTINUE INLAND BEFORE
THE WEST AND EAST COAST SEA BREEZES COLLIDE NEAR THE I-75 CORRIDOR
LATE IN THE AFTERNOON. TEMPS WILL BE IN THE LOW 90S EACH AFTERNOON
AND LOW TO MID 70S OVERNIGHT.

.LONG TERM (SUNDAY THROUGH THURSDAY)...
LONG TERM MODELS IN GENERALLY GOOD AGREEMENT SHOWING A LONG WAVE
TROUGH DOMINATING THE EASTERN US ON SUNDAY AND MONDAY BEFORE MOVING
OFF THE NORTHEAST ALLOWING RIDGING TO BUILD OVER THE FL PENINSULA
FOR TUESDAY THROUGH THURSDAY. SUNDAY AND MONDAY WILL BE
CHARACTERIZED BY SCATTERED TO NUMEROUS AFTERNOON CONVECTION WITH
DEEP LAYER MOISTURE PRESENT AND UPPER LEVEL SUPPORT PROVIDED BY A
COUPLE OF SHORTWAVES TRAVELING THROUGH GEORGIA. HIGH PRESSURE
BUILDS IN ON TUESDAY FROM THE SOUTHEAST AND A SLIGHT DECREASE IN
COVERAGE OF AFTERNOON SHOWERS AND THUNDERSTORMS IS EXPECTED EACH
DAY THROUGH THE END OF THE PERIOD. TEMPS WILL REMAIN NEAR SEASONAL
NORMALS.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH AT LEAST 16Z. ISOLATED
AFTERNOON SHOWERS AND THUNDERSTORMS MAY IMPACT SSI AND THE DUVAL
COUNTY TERMINALS TOWARDS 17Z-20Z AS THE ATLANTIC SEA BREEZE PUSHES
INLAND. VCTS WAS INCLUDED IN THE SSI TAF DURING THE AFTERNOON
HOURS...AND WITH SLIGHTLY LOWER CONFIDENCE FOR THE DUVAL COUNTY
TERMINALS...USED ONLY VCSH DURING THE AFTERNOON HOURS. ANY
ISOLATED ACTIVITY THAT IMPACTS THE TERMINALS SHOULD DISSIPATE
TOWARDS 00Z. SOUTHEAST WINDS WILL INCREASE TO 10-15 KTS BELOW 3000
FT AT SSI AND THE DUVAL COUNTY TERMINALS AS THE SEA BREEZE PUSHES
PAST THE TERMINALS TOWARDS 18Z.

&&

.MARINE...
A LOW PRESSURE TROUGH WILL REMAIN IN PLACE OVER OUR REGION
THROUGH THE UPCOMING WEEKEND...KEEPING ONSHORE WINDS IN PLACE
THROUGH FRIDAY. WINDS ARE EXPECTED TO SURGE TO JUST BELOW CAUTION
CRITERIA THIS EVENING...WITH SEAS OFFSHORE BUILDING TO 3-4 FT.
SCATTERED TO POSSIBLY NUMEROUS THUNDERSTORM COVERAGE IS EXPECTED
AFTER MIDNIGHT TONIGHT...AND THIS HIGHER COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL LIKELY PERSIST THROUGH THE UPCOMING WEEKEND.
HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL THEN GRADUALLY BUILD
WESTWARD INTO OUR REGION EARLY NEXT WEEK...WITH WINDS BECOMING
SOUTHERLY BY LATE SUNDAY AND THEN SOUTHWESTERLY TOWARDS MON
NIGHT/TUES.

RIP CURRENTS: LOW RISK TODAY. PERSISTENT ONSHORE WINDS MAY CREATE
A MODERATE RISK ON FRIDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  93  70  92  73 /  20  20  40  40
SSI  89  78  87  78 /  30  30  40  40
JAX  92  71  91  75 /  20  20  40  40
SGJ  90  75  89  76 /  20  20  40  40
GNV  95  69  92  73 /  10  10  50  50
OCF  95  70  92  73 /  20  10  50  50

&&

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

$$

NELSON/GUILLET






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