Red Flag Warning 44, NWS Jacksonville, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
246 PM EDT SUN APR 5 2009

...SLIGHT RISK OF SEVERE TSTMS THRU THE NIGHT...
...MUCH COLDER TEMPERATURES EARLY IN THE COMING WEEK...

.SYNOPSIS...WEAK UPPER RIDGE IS SHIFTING E OF THE AREA. SMALL BUT
POTENT SHORTWAVE IS PRESENTLY MOVING E ACROSS S CENTRAL GA. THIS
FEATURE IS ACTING ON INCREASED INSTABILITY S OF A WARM FRONT TO
PRODUCE SCATTERED STRONG TO SEVERE TSTMS JUST NW OF OUR COUNTY
WARNING AREA (CWA). MAIN IMPACT OF THESE STORMS IS LARGE HAIL. FAIRLY
THICK MULTI-LAYERED CLOUDINESS COVERS MOST OF THE AREA. S SFC FLOW
ACROSS THE AREA BUT STILL MOSTLY 10 KTS OR LESS. TEMPS RANGE FROM
NEAR 70 IN RECENT RAIN AREAS TO THE MID 80S OVER THE S INTERIOR.

.SHORT TERM...SHORTWAVE WILL CONTINUE MOVE ENE OVER THE N PORTION
OF THE CWA. STRONG TO SEVERE STORMS WILL PERSIST AS THEY MOVE
ACROSS THIS AREA. ACTIVITY ACROSS THE REMAINDER OF THE AREA WILL
BE SLOWER TO DEVELOP...BUT EXPECT AT LEAST LOW END SCATTERED
SHOWERS AND STORMS BY EVENING...ESPECIALLY ALONG SEABREEZE FRONTS
AND ANY OUTFLOWS FROM N CONVECTION.

LATER IN THE EVENING...NEGATIVE VORTICITY ADVECTION ON BACK SIDE
OF SHORTWAVE SHOULD REDUCE COVERAGE AND INTENSITY OF STORMS ACROSS
MUCH OF THE AREA. THE INFLUENCE OF THIS WILL DECREASE AFTER
MIDNIGHT...WITH ANOTHER ROUND OF SHOWERS AND TSTMS PRECEDING THE
APPROACHING COLD FRONT. COVERAGE OF PRECIP WILL LIKELY INCREASE AS
THE FRONT PROGRESSES ACROSS THE AREA...WITH 60% POPS ACROSS
PORTIONS OF NE FL AND EXTREME SE GA DURING THE 1ST HALF OF THE DAY
MON.

THE REMAINDER OF THE FORECAST HAS NOT CHANGED MUCH. STILL EXPECT
COLD AIR TO RUSH INTO THE AREA BEHIND THE COLD FRONT. A FREEZE IS
ANTICIPATED ACROSS MOST OF SE GA AND PORTIONS OF INTERIOR NE FL
WED MORNING AND A FREEZE WATCH MAY NEED TO BE ISSUED BY MON AFTN.

RECORDS FOR TUE AND WED MORNINGS...

        TUE 4/7     WED 4/8
AMG... 33 IN 1950  30 IN 2007
SSI... 36 IN 1950  37 IN 2007
JAX... 37 IN 1950  31 IN 2007
GNV... 37 IN 1950  35 IN 2007

.LONG TERM...TEMPERATURES WILL RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL BY THE LATTER HALF OF THE COMING WEEK. NEXT COLD FRONT WILL
MOVE INTO THE AREA FRI NIGHT AND SAT BRINGING ANOTHER CHANCE OF
PRECIP. HAVE MADE ONLY MINOR CHANGES TO THE EXTENDED PACKAGE.

&&

.AVIATION...EXPECTING CONDITIONS TO GRADUALLY DETERIORATE THIS
EVENING INTO THE OVERNITE HOURS AS THE COLD FRONT APPROACHES. A
SHORT WAVE MOVING JUST NORTH OF THE AREA THIS EVENING MAY ALSO
PRODUCE ISOLATED SHOWERS/STORMS AND HAVE VCSH IN ALL TERMINALS.
EXPECTING MVFR CIGS AT GNV AROUND 03Z AND REST OF TERMINALS AROUND
05Z. STRONG LOW LEVEL JET FORMS OVER THE AREA JUST PRIOR TO 12Z AND
HAVE LOW LEVEL WIND SHEAR BEGINNING AT 06Z AT ALL TERMINALS AND
CONTINUING THROUGH MONDAY MORNING. COLD FRONT PROGGED TO MOVE
THROUGH BETWEEN 12Z-16Z AND HAVE PREVAILING SHRA WITH VCTS AT ALL
TERMINALS WITH TEMPO TS AND IFR CONDITIONS.

&&

.MARINE...WINDS/SEAS INCREASE TONIGHT WITH APPROACH OF COLD FRONT
AND WILL CONTINUE WITH CURRENT ADVISORY FOR THE OFFSHORE. COLD FRONT
MOVES THROUGH MONDAY MORNING WITH SCATTERED TO NUMEROUS
SHOWERS/STORMS. WINDS SHIFT TO WEST AND INCREASE BEHIND FRONT LATE
MONDAY/TUESDAY. MAY POSSIBLY NEED A GALE WARNING OFFSHORE AND AN
ADVISORY NEAR SHORE FOR A PERIOD FROM MONDAY NIGHT INTO TUESDAY
MORNING.

&&

.FIRE WEATHER...A COLD FRONT WILL SWEEP THROUGH THE AREA MONDAY
MORNING. AN UPPER DISTURBANCE WILL BRING SCATTERED STORMS THIS
AFTERNOON AND EVENING. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS WILL ACCOMPANY THE FRONT LATE TONIGHT INTO MONDAY
MORNING. SOME STORMS MAY BE SEVERE AND PRODUCE LARGE HAIL AND
DAMAGING WINDS. IN THE WAKE OF THE COLD FRONT MONDAY...BRISK
WESTERLY WINDS WILL ADVECT MUCH DRIER AIR INTO THE AREA. CRITICALLY
LOW RH VALUES ARE FORECAST AREAWIDE ON TUESDAY ALONG WITH GUSTY
WESTERLY WINDS AND HIGH DISPERSIONS. THIS HAS PROMPTED THE ISSUANCE
OF A FIRE WEATHER WATCH. VERY DRY CONDITIONS WILL PERSIST THROUGH AT
LEAST MIDWEEK WITH RED FLAGS ANTICIPATED ON WEDNESDAY ACROSS
NORTHEAST FLORIDA.

&&

.HYDROLOGY...RIVER FLOOD WARNINGS HAVE BEEN UPDATED A FEW TIMES
TODAY TO INCLUDE THE LATEST FORECAST RIVER LEVELS. WILL LIKELY SEE
RECORD FLOODING AT STATENVILLE AND ATKINSON AND NEAR RECORD FLOODING AT
WAYCROSS. MAJOR FLOODING IS ALSO EXPECTED ALONG THE SANTA FE RIVER
AT HILDRETH AND 3 RIVERS ESTATES. SEE THE LATEST FLS AND FLW
PRODUCTS FOR THE MOST RECENT RIVER FORECASTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  60  66  35  56 /  50  30  10   0
SSI  64  70  39  58 /  20  40  10   0
JAX  65  72  38  59 /  20  50  10   0
SGJ  67  76  44  60 /  20  60  10   0
GNV  66  73  40  59 /  30  60  10   0
OCF  66  76  42  61 /  20  50  10   0

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...FIRE WEATHER WATCH FROM TUE AFTERNOON THRU TUE EVENING FOR
     ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL-FLAGLER-GILCHRIST-
     HAMILTON-MARION-NASSAU-PUTNAM-ST JOHNS-SUWANNEE-UNION.

GA...FIRE WEATHER WATCH FROM TUE AFTERNOON THRU TUE EVENING FOR
     APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COASTAL CAMDEN-
     COASTAL GLYNN-COFFEE-ECHOLS-INLAND CAMDEN-INLAND GLYNN-
     JEFF DAVIS-PIERCE-WARE-WAYNE.

AM...SMALL CRAFT ADVISORY FROM 5 AM MON TO 10 AM WED FOR
     ALTAMAHA SOUND GA TO FLAGLER BEACH FL 20 NM TO 60 NM
     OFFSHORE.

&&

CARROLL/PETERSON/KERNS