217
FXUS62 KJAX 071915
AFDJAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
210 PM EST SAT NOV 7 2009
SYNOPSIS
MID AND UPPER LEVEL RIDGE DOMINATES THE SRN U.S. WITH
SFC ANALYSIS SHOWING RIDGE FROM NC TO LA AND ERN TX. OBSERVATIONS
SHOW TEMPS IN THE LOWER TO MID 70S WITH UPPER 70S NOTED OVER
MARION COUNTY. A SCT STRATOCU FIELD HAS EXPANDED INTO MOST OF NE
FL AND PORTIONS OF SE GA. T.S. IDA NOW A BIT STRONGER WITH WINDS
OF NEAR 70 MPH AND PSN ABOUT 230 MILES SE OF COZUMEL MEXICO...MOVING
N ABOUT 9 MPH AT 1 PM.
SHORT TERM
TONIGHT-TUE.
MODEL GUIDANCE SHOWS THE AFOREMENTIONED MID-UPPER LEVEL RIDGE AXIS TO
SHIFT EWD AND AN UPPER TROUGH OVER S CONUS MOVING EWD AND ALLOWING
IDA TO CONTINUE ON A GENERAL NWD TRACK. THIS WILL ALLOW A WARM UP AS
THE ENE FLOW TRANSITIONS TO MORE E AND THEN SE DURING THE PERIOD.
DEEP LAYER MOISTURE IS EXPECTED TO INCREASE FROM THE SW AND W
BETWEEN MON AND TUE WITH THE BEST LIFT INDICATED FROM THE GFS MOVING
INTO THE AREA ON TUE. THE OPERATIONAL GFS IS IN REASONABLY GOOD
AGREEMENT WITH THE CURRENT 12Z GFS ENSEMBLE AND THE 00Z ECMWF AS FAR
AS DEEP LAYER MOISTURE AND THE LLVL WIND FIELDS. POPS FORECAST SHOWS
10-20% ON MON TO 30-50% MON NIGHT AND 50-60% ON TUE...USING A BLEND
OF THE ENSEMBLE GUIDANCE AND THE GFS MOS. FOR TUE TIME FRAME...
INSERTED A SLIGHT CHANCE OF THUNDER GIVEN THE WEAK INSTABILITY BUT
COMPENSATED BY RELATIVELY STRONG SHEAR. RAINFALL AMOUNTS COULD BE ON
THE HEAVY SIDE AT TIMES GIVEN THE DEEP TROPICAL MOISTURE MOVING INTO
THE AREA LATE MON NIGHT THROUGH EARLY WED. AS FAR AS WINDS ...ELY
FLOW EXPECTED TO INCREASE TO AT BREEZY AS THE PRESSURE GRADIENT
CONTINUES TO INCREASE AS IDA PROGRESS NWD BUMPING UP AGAIN THE SFC
RIDGE TO OUR N AND NE. ELY WINDS AROUND 15-20 MPH EXPECTED SUN AND
MON ALONG NE FL COASTAL AREAS WITH GUSTS UP TO 25-30 MPH WITH MORE
SELY FLOW EXPECTED ON TUE BUT WIND SPEEDS MAY BE A BIT LOWER AS THE
HIGH PRESSURE SYSTEM MOVES FURTHER AWAY FROM THE AREA.
LONG TERM
(WED-SAT).
STILL MUCH UNCERTAINTY IN THE EARLY PORTIONS OF THE EXTENDED
FORECAST REGARDING REMAINS OF IDA. TPC HAS THE SYSTEM ABOUT 100
MILES S OF APALACHICOLA WED MORNING. LATE WED THROUGH THU...
EXPECTATION IS THAT IDA WILL SHIFT EWD AND THE FRONTAL ZONE WILL
PUSH SWD AS HIGH PRESSURE BUILDS IN FROM THE N THROUGH AS MID LEVEL
TROUGHING MOVES OFF THE E COAST. THE HIGH PRESSURE RIDGE WILL LIKELY
DOMINATE THE REGION JUST TO OUR N FRI AND SAT RESULTING IN
LITTLE...IF ANY...RAIN CHANCE AND AN ELY LOW LEVEL FLOW.
AVIATION
VFR CONDITIONS ARE ANTICIPATED THROUGH THE PERIOD. MODEL
GUIDANCE DOES SHOW SLIGHT REDUCTIONS TO VSBY POSSIBLE TONIGHT BUT
INCREASED WINDS ABOVE THE SURFACE SHOULD PRECLUDE REDUCTIONS BELOW
6SM. WINDS WILL BE A FACTOR...ESPECIALLY FOR THE EAST COAST
TERMINALS WITH OCCASIONAL GUSTS TO 20 KNOTS TODAY AND 25 KNOTS ON
SUNDAY.
MARINE
TIGHTEST OBSERVED GRADIENT TODAY HAS REMAINED SOUTH OF
OUR COASTAL WATERS TODAY WITH PREDOMINANT 15 KNOTS OVER THE
NEARSHORE AND 15 TO 20 OVER THE OFFSHORE. THIS IS INLINE WITH
MODEL INITIALIZATIONS AND CONFIDENCE IS HIGH FOR THE SHORT TERM. AS
IDA LIFTS NORTH AND MODERATELY STRONG HIGH REMAINS OVER THE
CAROLINAS...GRADIENT SHOULD TIGHTEN FROM SOUTH TO NORTH THROUGH
NEXT WEEK. WINDS JUST OFF THE SURFACE LOOK TO INCREASE TO 20 TO 25
KNOTS...BUT NOT UNTIL 12Z SUN AND WILL THEREFORE DELAY THE ONSET
OF SCA IN LATEST GRID SET FOR THE OFFSHORE FLORIDA PORTION.
CONSIDERING THE CIRCUMSTANCES WITH IDA LIKELY BECOMING
EXTRATROPICAL IN THE EXTENDED...LONG TERM GUIDANCE IS IN
EXCEPTIONAL AGREEMENT. THEREFORE CONFIDENCE IS A LITTLE HIGHER
THAN OTHERWISE FOR AN EVENT SUCH AS THIS AND HAVE RAMPED UP WINDS
A LITTLE FURTHER IN THE LONG TERM. STILL NOT GOING AS HIGH AS THE
30 KNOTS SUSTAINED IN THE ECMWF BUT A BLEND WITH THE GFS YIELDS
CLOSE TO 25 KNOTS AT TIMES IN POST FRONTAL ENVIRONMENT ON WED.
WILL LIKELY NEED HIGH RISK OF RIP CURRENTS FOR AT LEAST THE
FLORIDA PORTION ON SUNDAY AS WINDS INCREASE THROUGH THE AFTERNOON.
WILL UPDATE CURRENT OUTLOOK TO REFLECT THIS CHANGE.
PRELIMINARY POINT TEMPS/POPS
AMG 47 79 56 78 / 0 0 10 10
SSI 57 75 63 76 / 0 10 10 20
JAX 55 78 60 78 / 0 0 10 20
SGJ 62 78 69 80 / 0 0 10 20
GNV 53 81 60 82 / 0 0 0 20
OCF 56 82 62 84 / 10 0 0 20
JAX WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY FROM 7 AM SUNDAY TO 7 AM EST TUESDAY FOR
FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-
ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE.
SHASHY/DEESE/KEEGAN
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