Area Forecast Discussion
Issued by NWS Melbourne, FL

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FXUS62 KMLB 180938 AAA
AFDMLB

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MELBOURNE FL
438 AM EST THU DEC 18 2014

.DISCUSSION...

CURRENT...
SKIES HEAVE CLEARED OUT...AT LEAST BRIEFLY...AS THE FIRST SWATH OF
HIGH CLOUDS HAS PASSED WELL E-SE OF CENTRAL FL. THIS HAS ALLOWED
TEMPS TO FALL OFF A BIT MORE...AND AS A RESULT SOME SHALLOW MIST HAS
FORMED ACROSS WESTERN FL. MORE CI/CS IS POISED TO MOVE BACK OVHD
BEFORE SUNRISE...THOUGH IR IMAGERY INDICATES THIS SHOULD REMAIN
THIN. GIVEN CURRENT T/TD SPREADS OF 2-4F DO NOT EXPECT ANYTHING MORE
THAN LOCALIZED SHALLOW MIST/GROUND FOG TO FORM.

TODAY/TONIGHT...
WEAK HIGH PRESSURE WILL PROVIDE A DRY AND SEASONABLY COOL DAY WITH
MAXES A COUPLE DEGREES BELOW CLIMO...OWING IN PART TO HIGH CLOUDS
DIMMING THE SUN AS THEY STREAM OVHD. MAXES IN THE U60S TO L70S WITH
MINS IN THE 40S.

FRI-SAT...
A 100-110KT H30-H20 JET STREAK EXTENDING FROM THE RIO GRANDE VALLEY
TO THE MID ATLC COAST WILL PUSH AN H100-H70 RIDGE CENTERED OVER THE
GOMEX EWD ACRS THE BAHAMA BANK WHILE PULLING A WEAK SHORTWAVE TROF
FROM THE HIGH PLAINS INTO THE DEEP SOUTH. MOISTURE ASSOCD WITH THE
RIDGE REMAINS LOW E OF THE MS RIVER WITH H100-H70 MEAN RH VALUES BLO
50PCT...H85-H50 VALUES BLO 30PCT.

MUCH DEEPER MOISTURE NOTED W OF THE MS RIVER WITH BOTH H100-H70 RH
VALUES AS HIGH AS 90PCT OVER THE CENTRAL/SRN PLAINS...H85-H50 VALUES
AOA 70PCT. NOTEWORTHY H85-H50 VORT MAXES WORKING THEIR WAY INTO THE
SRN PLAINS AS WELL. HOWEVER... THESE WX FEATURES ARE EMBEDDED WITHIN
THE STRONG AND DEEP ZONAL FLOW PATTERN OVER THE SRN TIER STATES THAT
WILL CARRY THEIR BULK ACRS THE DEEP SOUTH RATHER THAN INTO THE
GOMEX. INDEED...THE 18/00Z GFS HAS BACKED OFF FROM EARLIER SOLUTIONS
OF DLVPG A CLOSED LOW ALONG THE FRONTAL BNDRY...INSTEAD NOW
INDICATING A WEAK OPEN WAVE AS THE PRIMARY DRIVING FEATURE FOR THE
FRONT.

WITH THE CURRENT GOMEX RIDGE EXPECTED TO RELOCATE OVER THE SW ATLC
AND WEAK SWD MOTION ON THE FRONT...THERE WILL BE LITTLE TO KEEP IT
FROM LAYING DOWN AND OVER THE PANHANDLE. PTLY CLOUDY SKIES LIGHT NE
WINDS ON FRI AS THE RIDGE PUSHES TO THE ERN SEABOARD...VEERING TO
THE S/SE ON SAT AS THE FRONT STALLS TO THE NORTH. SEASONABLE MAX
TEMPS FRI DAYTIME MAXES IN THE L/M70S...MIN TEMPS ARND 5F ABV  AS
THE ONSHORE FLOW PUSHES OCEAN MODIFIED AIR ACRS THE STATE. SAT/SAT
NIGHT TEMPS WILL CONTINUE ARND 5F ABV AVG AS WINDS SHIFT TO THE
S/SE. WILL INTRODUCE SLGT CHC POPS INTO THE FCST N OF I-4 SAT
NIGHT...BUT ANY IMPACTS WOULD BE MINOR.

SUN-WED...
AN UNSETTLED WX PATTERN IN STORE THRU THE MIDDLE OF NEXT WEEK AS A
BROAD SHORT WAVE TROF OVER THE MOUNTAIN WEST COAST WORKS ITS WAY
ACRS THE CONUS. EXTENDED MODEL SOLUTIONS INDICATE THAT A 160KT
H30-H20 JET STREAK OVER THE PACIFIC WILL PUSH INTO THE PAC NW AND
FEED ITS ENERGY DOWN STREAM TO THE LIFTING JET OVER THE SE CONUS.
HOWEVER... BOTH GFS/ECMWF MODELS MAINTAIN A LIFTING ORIENTATION WITH
THE SRN JET WHILE HOLDING THE RIDGE OVER THE SW ATLC FIRMLY IN
PLACE. BOTH OF THESE WX FEATURES WILL PREVENT THE FRONT FROM MAKING
A CLEAN OR RAPID PASS THRU CENTRAL FL...RESULTING IN AN EXTENDED PD
OF PRECIP AS DEEP MOISTURE POOLS WITHIN THE FRONTAL TROF.

INTERACTION BTWN THE ATLC RIDGE AND THE STALLED FRONTAL TROF WILL
GENERATE A DEEP SW FLOW THRU THE COLUMN...RESULTING IN STRONG
ISENTROPIC LIFT THAT USUALLY GENERATES MORE STRATIFORM THAN
CONVECTIVE RAIN. HOWEVER...AS THE FRONTAL TROF DRIFTS INTO THE
CENTRAL PENINSULA...IT WILL ERODE THE WRN FLANK OF THE ATLC RIDGE
AND BREAK UP THE STRONG SUBSIDENCE INVERSION THAT CURRENTLY
DOMINATES THE H100-H70 LYR ACRS CENTRAL/NORTH FL. TEH STEEPENING
LAPSE RATES WILL COMBINE WITH H50 TEMPS BTWN -10C/-12C THAT COULD
TRIGGER ISOLD TSRAS.

WILL KEEP PRECIP MENTIONED IN THE FCST THRU THE PD BUT AOB 50PCT. A
PROLONGED PD OF S/SWRLY FLOW AHEAD OF THE FRONT WILL KEEP TEMPS ABV
AVG...THOUGH CLOUDS AND RAIN COOLED AIR WILL HELP OFFSET THIS EFFECT
IN THE DAYTIME. AFTN MAXES IN THE L/M70S N OF I-4...M/U70S TO THE S.
MIN TEMPS U50S/L6S0 INTERIOR AND L/M60S ALONG THE COAST.

&&

.AVIATION...
VFR. COULD SEE A LITTLE PATCHY MIFG 10Z-13Z...BUT WOULD BE TRANSIENT
AND QUITE SHALLOW.

&&

.MARINE...
TODAY/TONIGHT...FINE BOATING CONDITIONS WITH A GENTLE NW-N BREEZE
AOB 10KT AND SEAS 1FT NEARSHORE/2FT OFFSHORE

FRI-FRI NIGHT...A HI PRES RIDGE EXTENDING FROM THE NRN GOMEX TO THE
GREAT LAKES WILL WEAKEN AS IT DRIFTS TOWARD THE ERN SEABOARD. AS IT
DOES...THE PREVAILING LIGHT TO GENTLE NRLY BREEZE WILL VEER TO THE
NE BY THRU THE DAY...TO THE E BY MIDNIGHT...THEN TO THE S/SE THRU
DAYBREAK. FAVORABLE BOATING CONDITIONS TO CONTINUE WITH SUSTAINED
WIND SPEEDS AOB 10KTS...SEAS GENERALLY AOB 2FT...UP TO 3FT IN THE
GULF STREAM.

SAT-MON...A WEAK H100-H70 SHORTWAVE WILL PINCH OFF OF THE BASE OF
THE TROF OVER THE WRN CONUS AND PUSH ACRS THE DEEP SOUTH ON
SAT...DRAGGING A COOL FRONT INTO THE FL PANHANDLE WHERE IT IS
EXPECTED TO STALL BY LATE SAT NIGHT. THIS WILL RESULT IN A
PERSISTENT LIGHT TO GENTLE SRLY BREEZE THRU THE WEEKEND...BCMG S/SW
GENTLE TO MODERATE ON MON AS A REINFORCING TROF PUSHES INTO THE
GOMEX REGION AND NUDGES THE FRONT INTO THE NRN PENINSULA. SEAS AOB
2FT NEARSHORE AND 2-3FT OFFSHORE.

&&

.FIRE WEATHER...MINIMUM RH VALUES DROPPING INTO THE 30S ONCE AGAIN
ACROSS A GOOD PORTION OF THE CWA. WINDS AND ERC VALUES REMAIN BELOW
CRITICAL THRESHOLDS...ALTHOUGH LIGHT WINDS WILL LIMIT DISPERSION TO
POOR-FAIR TODAY.

&&

.HYDROLOGY...LATEST AHPS DATA SHOWS THE GAGE ON THE ST JOHNS RIVER
ABOVE LAKE HARNEY (GENF1) HAS DROPPED TO 6.45FT...BELOW THE ACTION
STAGE OF 6.50FT. DRY WEATHER THE NEXT COUPLE OF DAYS WILL ENSURE A
CONTINUED SLOW FALL.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  66  47  69  54 /   0   0  10  10
MCO  70  48  72  53 /   0   0  10   0
MLB  69  47  72  57 /   0   0  10   0
VRB  71  45  72  56 /   0   0  10   0
LEE  67  46  70  52 /   0   0  10  10
SFB  69  48  71  53 /   0   0  10  10
ORL  70  49  71  54 /   0   0  10  10
FPR  70  45  73  57 /   0   0  10   0

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.

&&

$$

SHORT TERM/AVIATION...CRISTALDI
LONG TERM/IMPACT WX...BRAGAW





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