Area Forecast Discussion
Issued by NWS Melbourne, FL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KMLB 190901
AFDMLB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
401 AM EST FRI DEC 19 2014

.DISCUSSION...

...RATHER BENIGN WEATHER INTO THE WEEKEND THEN INCREASING CHANCE
FOR SHOWERS AND STORMS FROM LATE SUNDAY INTO EARLY WED...

TODAY-TONIGHT...
EVNG RAOBS SHOW A VERY DRY/STABLE AIRMASS ACRS CNTRL/SRN FL...BUT
INCREASING MID/UPR LVL CLOUDS OVER N FL ASSOCD WITH A 110-130KT
H30-H20 JET STREAK EXTENDING FROM THE RIO GRANDE VALLEY TO THE MID
ATLC COAST. THIS JET WILL PUSH AN H100-H70 RIDGE FROM THE CENTRAL
GOMEX ACRS THE FL PENINSULA TODAY...THEN E OF THE BAHAMA BANK
OVERNIGHT. SFC WINDS WILL RESPOND BY VEERING FROM N TO NE THRU EARLY
AFTN...TO THE E BY MIDNIGHT...THEN TO THE S/SE BY DAYBREAK.
UPSTREAM...LOW LVL MOISTURE ASSOCD WITH THE RIDGE REMAINS WITH
H100-H70 MEAN RH VALUES BLO 50PCT. MID/UPR LVL MOISTURE A BIT HIGHER
WITH H85-H50 VALUES BTWN 60-80PCT...H40-H20 VALUES ARND
50PCT...MATCHING UP WELL WITH THE AFOREMENTIONED JET.

AS THE JET PASSES OVER THE SE CONUS...MID/UPR LVL CLOUD DECK WILL
STREAM ACRS THE N HALF OF THE PENINSULA WITH SOME HI CLOUDS WORKING
THEIR WAY S OF SR60. THIS SHOULD WORK TO KEEP AFTN MAX TEMPS IN THE
U60S ALONG AND N OF THE I-4 CORRIDOR...WHILE L/M70S WILL BE THE RULE
TO THE S. LOW/MID LVL MOISTURE WILL INCREASE AS WELL AS WINDS THRU
THE H100-H70 VEER TO AN ONSHORE COMPONENT. HOWEVER...DEWPOINT
DEPRESSIONS IN THE H85-H50 LYR ACRS CENTRAL/SRN FL ARE ON THE ORDER
OF 30-35C AND WILL REQUIRE SUBSTANTIAL MODIFICATION BEFORE PRECIP
CAN BE INTRODUCED TO THE FCST.

WEEKEND...
SAT...WEAK LOW LEVEL HIGH PRESSURE RIDGE WILL PRODUCE A LIGHT ONSHORE
FLOW. ZONAL/UNPERTURBED FLOW ALOFT LOCALLY WILL PROMOTE A CONTINUED
SUBSIDENCE INVERSION AND KEEP LOW LEVEL MOISTURE SHALLOW. HENCE
THE FORECAST WILL REMAIN DRY. MAX TEMPS WILL MODIFY BUT A CONTINUED
STREAM OF HIGH LEVEL CLOUDS SHOULD LIMIT THIS TO ABOUT 3-5 DEGREES...
WITH HIGHS IN THE MID 70S EXCEPT FOR LOWER 70S NORTH AND MAYBE SOME
UPPER 70S AROUND OKEECHOBEE.

SUN/SUN NIGHT...TROUGH MOVING INTO THE WESTERN GULF IS FORECAST TO
INDUCE A WEAK LOW PRESSURE WAVE IN THE CENTRAL GULF. INITIAL MID
LEVEL DRY LAYER WILL STEADILY MOISTEN AHEAD OF THIS SYSTEM BUT
FORECAST SOUNDINGS DO NOT SHOW EROSION OF THE DRY LAYER UNTIL SUN
NIGHT. SO THE CHANCE FOR SHOWERS ON SUNDAY LOOKS LOW AND HAVE GONE
WITH A MAX OF 30 PERCENT IN THE NORTH BUT KEPT POPS OUT OF THE
FORECAST IN THE SOUTH. MOS POPS JUMP TO OVER 70 PERCENT IN THE
NORTH SUNDAY NIGHT AND 50 IN THE SOUTH. THIS LOOKS REASONABLE AND
HAVE FOLLOWED CLOSE TO THOSE NUMBERS. DIVERGENCE ALOFT AND LOW
LEVEL WARM ADVECTION SHOULD GENERATE SOME ELEVATED INSTABILITY AND
SLIGHT THUNDER CHANCES TOO...ESPECIALLY ACROSS THE NORTH.

MON THRU NEXT FRI...
MAIN FEATURE WILL BE A TROUGH THAT DIGS OVER THE MID SECTION OF THE
COUNTRY AND INTO THE GULF OF MEXICO...PRODUCING A STRONG COLD
FRONTAL PASSAGE AT MID WEEK.

MON...BAND OF HIGH MOISTURE AND WEAK DIVERGENCE ALOFT IS PROGGED
TO LINGER OVER THE AREA. CONSENSUS POPS ARE 30 PERCENT SOUTH AND
50 NORTH AND HAVE FOLLOWED...BUT MAY END UP BEING A BIT HIGHER IN
LATER FORECASTS.

TUE-WED...THE AMPLIFYING TROUGH OVER THE MID SECTION OF THE
COUNTRY WILL GENERATE A SECONDARY SURFACE LOW OVER THE DEEP SOUTH
TUESDAY...WHICH WILL LIFT QUICKLY NORTHEAST THROUGH TUE NIGHT.
THIS WILL INCREASE LOW LEVEL WINDS WITH 925-850 MB SPEEDS NEAR 40
KNOTS INDICATED. THE ECMWF IS EVEN A LITTLE STRONGER. THEREFORE
EXPECT A SLIGHT CHANCE FOR STRONG STORMS AS A PRE FRONTAL BAND OF
CONVECTION MOVES ACROSS THE AREA. RIGHT NOW THE GREATEST CHANCE
FOR HEAVY RAIN AND STRONG STORMS IS FAVORING TUE NIGHT. SOME
CONVECTION MAY LINGER INTO WED THEN COOL/DRY AIR ADVECTION WILL
SWEEP IN WITH A BREEZY DAY INDICATED.

CHRISTMAS-FRI...IT WILL START OFF COOL ON CHRISTMAS WITH LOWS
MOSTLY IN THE 40S. SURFACE HIGH PRESSURE RIDGE WILL PROVIDE A SUNNY
DAY AND HIGH TEMPS A LITTLE BELOW NORMAL. THE RIDGE WILL PUSH
OFFSHORE FRI AND TEMPS SHOULD MODIFY TO NORMAL OR SLIGHTLY ABOVE
WITH CONTINUED DRY WEATHER.

&&

.AVIATION...
SFC WINDS: THRU 19/15Z...VRBL AOB 3KTS. BTWN 19/15Z-19/18Z...N/NE
ARND 5KTS. AFT 19/18Z...E/NE BTWN 5-8KTS.

VSBYS/CIGS: THRU 20/00Z...VFR ALL SITES...PREVAILING CIGS AOA FL120
N OF KMLB-KISM.

&&

.MARINE...
TODAY-TONIGHT...A HI PRES RIDGE OVER THE GOMEX WILL WEAKEN AS IT
DRIFTS ACRS CENTRAL FL TODAY...THE E OF THE BAHAMA BANK OVERNIGHT.
AS IT DOES...THE PREVAILING LIGHT TO GENTLE NRLY BREEZE WILL VEER TO
THE NE BY EARLY AFTN...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.

WEEKEND...A WEAK PRESSURE PATTERN WILL RESULT IN WINDS 5 TO 10
KNOTS SAT...MAINLY FROM THE SOUTH OR SOUTHEAST. A SLIGHT INCREASE
IN SOUTHEAST WINDS TO NEAR 10 KNOTS IS INDICTED ON SUNDAY. THOUGH
SKIES WILL BE MOSTLY CLOUDY AT TIMES...ESPECIALLY SUNDAY...THERE
WILL BE NO RAIN CHANCES UNTIL SUNDAY AFTERNOON.

MON-TUE...HIGH SHOWER CHANCES WITH ISOLATED STORMS ARE FORECAST
SUNDAY NIGHT AND MAY LINGER INTO MON. WINDS WILL BE VEERING TO THE
SOUTH AND SHOULD START TO INCREASE AHEAD OF A STRONG COLD FRONT
ESPECIALLY LATE ON TUE. WITH HIGH MOISTURE CONTINUING TUE...THERE
WILL BE A CHANCE FOR SHOWERS AND A SLIGHT CHANCE FOR STORMS.

&&

.FIRE WEATHER...
TODAY...LIGHT NRLY SFC/TRANSPORT WINDS WILL VEER TO THE NE BY
EARLY AFTN AS A WEAK HI PRES RIDGE PUSHES ACRS THE FL PENINSULA.
POOR TO FAIR DISPERSION WILL CONTINUE AS A STRONG SUBSIDENCE
INVERSION KEEPS MIXING HEIGHTS BLO 2500FT. AFTN RH VALUES ALONG
AND N OF THE I-4 CORRIDOR WILL FALL BLO 35PCT FOR 4-6HRS...BUT ERC
VALUES REMAIN TOO LOW TO TRIGGER CRITICAL FIRE CONDITIONS.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  68  57  71  57 /   0  10  10  10
MCO  69  54  75  57 /   0   0  10  10
MLB  72  59  75  60 /   0   0  10  10
VRB  73  59  76  58 /   0   0  10  10
LEE  69  53  72  56 /   0  10  10  10
SFB  69  55  74  57 /   0  10  10  10
ORL  69  55  74  58 /   0  10  10  10
FPR  73  59  76  58 /   0   0  10  10

&&

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

$$

SHORT TERM...BRAGAW
LONG TERM....LASCODY



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.