Area Forecast Discussion
Issued by NWS Melbourne, FL

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FXUS62 KMLB 221351
AFDMLB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
950 AM EDT TUE JUL 22 2014

.DISCUSSION...

CURRENT-THIS AFTERNOON...
SHOWERS AND STORMS OVER THE GULF STREAM MOVING NORTH AND AWAY FROM
LAND. LATEST RUC SURFACE ANALYSIS AND 500MB PLOT SHOWS INVERTED
TROUGHING PATTERN OVER FLORIDA AND UNDER THE SOUTH TO SOUTHWEST FLOW
AHEAD OF THE UPPER LEVEL LOW OVER SOUTHERN ALABAMA.

VERY MOIST ATMOSPHERE WITH PRECIPITABLE WATER VALUES AROUND 2 INCHES
WILL CONTINUE TODAY. THE STRONGER MID LEVEL SUPPORT...VORTICITY...
IS NORTH OF CENTRAL FLORIDA THUS CONVECTION WILL BE BY SEA BREEZE
INITIATION AND BOUNDARIES INTERACTING WITH EACH OTHER IN THE
AFTERNOON AND LINGERING ON THROUGH THE EVENING.

WEAK STEERING FLOW WILL MEAN THAT STORMS WILL BE CAPABLE OF
PRODUCING HEAVY RAIN ALONG WITH GUSTY DOWN BURSTS WINDS AND CLOUD TO
GROUND LIGHTNING STRIKES. MID LEVEL TEMPERATURES OVER CENTRAL AND
NORTH FLORIDA PER THE 6AM AND 8AM SOUNDINGS WERE AROUND -6C WHILE TO
THE NORTH...TALLAHASSEE AND TO THE SOUTH...KEY WEST... THE 500MB
TEMPERATURES WERE COOLER AT -8.5C AND -7.1C RESPECTIVELY. YESTERDAY
PROVED THAT SMALL HAIL MAY NOT BE RULED OUT EVEN WITH 500MB
TEMPERATURES IN THE -6C TO -7C RANGE.

NO SIGNIFICANT CHANGES PLANNED FOR THE MORNING ZONE UPDATE.

PREVIOUS ZONES DISCUSSION
TODAY-TONIGHT...CUT OFF LOW ALOFT ACROSS THE WESTERN FLORIDA
PANHANDLE WILL RETROGRADE SLIGHTLY TO THE MISSISSIPPI DELTA
REGION. THIS WILL ALLOW ATLANTIC RIDGE TO NUDGE WESTWARD TOWARDS
THE FLORIDA PENINSULA. A DEEP LAYER OF SOUTHERLY FLOW WILL DEVELOP
AS A RESULT...WHICH SHOULD LIFT A VERY WEAK LOW LEVEL TROUGH OUT TO
THE NORTH OR GRADUALLY WASH IT OUT. THIS WEAK TROUGH HAS BEEN
FOCUSING MOISTURE CONVERGENCE ALONG THE COAST EARLY THIS MORNING
WITH SCATTERED SHOWERS OCCURRING. THIS MAY CONTINUE FROM THE CAPE
NORTH INTO LATE MORNING.

THE DEEP SOUTHERLY FLOW WILL KEEP HIGH MOISTURE IN PLACE. THE GFS
SHOWS PRECIPITABLE WATER 2 INCHES OR GREATER. THIS SHOULD LEAD TO
A LITTLE EARLIER THAN NORMAL CONVECTIVE INITIATION ALONG THE EAST
COAST SEA BREEZE...DURING THE LATE MORNING OR EARLY AFTERNOON. A
LIGHT SOUTHWEST STEERING FLOW IS FORECAST WHICH MIGHT KEEP THE SEA
BREEZE CONVECTION NEAR THE COAST WELL INTO THE AFTERNOON. EXPECT
THAT OUTFLOW BOUNDARIES WILL PUSH INLAND DURING THE MID TO LATE
AFTERNOON AND STRONGER BOUNDARY INTERACTIONS SHOULD OCCUR ACROSS
THE INTERIOR COUNTIES. THEREFORE EXPECT BOTH COAST AND INLAND TO
GET A RATHER HEALTHY COVERAGE OF SHOWERS AND STORMS. MOS POPS ARE
50-60 PERCENT BUT WILL GO WITH LIKELY RAIN CHANCES AREAWIDE.

A FEW SHOWERS/STORMS MAY LINGER A LITTLE PAST SUNSET SO WILL MATCH
THE 20-30 PERCENT MOS POPS FOR THIS EVENING.

WED-THU...MID-LEVEL TROUGH OVER THE NORTH GOMEX WILL RETROGRADE
SLOWLY TOWARD THE SOUTHERN LOUISIANA COAST...THEN EVENTUALLY WILL
WEAKEN AND BECOME STRETCHED OUT NORTHEAST-SOUTHWEST FROM THE MID
ATLC STATES THROUGH THE TEXAS EAST COAST. MID-LEVEL RIDGING OVER THE
BAHAMAS/FLORIDA PENINSULA WILL GRADUALLY WEAKEN AND BECOME
SUPPRESSED SOUTHEASTWARD BY THE END OF THE PERIOD. DEEP LAYER
MOISTURE VALUES IN THE NEIGHBORHOOD OF TWO INCHES WILL BE COMMON.
THE PRESSURE GRADIENT AT THE SURFACE REMAINS WEAK WITH LIGHT WINDS
AND DAILY INLAND MOVING SEA BREEZES ON EITHER SIDE OF THE PENINSULA.
TEMPERATURES AT 500 MB ARE FORECAST TO BE RELATIVELY WARM FROM -6C
TO -7C BUT PARAMETERS WILL STILL BE PRESENT TO CONTINUE SLIGHTLY
ABOVE SEASONAL POP CHANCES IN THE 40 TO 50 PERCENT RANGE EACH
AFTERNOON/EARLY EVENING. STEERING FLOW FOR STORMS WILL REMAIN LIGHT
AND ERRATIC. THE MAIN THREATS FROM STORMS CONTINUE TO BE LOCALLY
HEAVY RAINFALL...FREQUENT LIGHTNING AND GUSTY WINDS. AFTERNOON HIGHS
IN THE UPPER 80S TO AROUND 90 DEGREES AT THE COAST WITH LOW TO MID
90S INLAND. HEAT INDICES WILL RANGE FROM 98F-103F EACH AFTERNOON.
OVERNIGHT LOWS IN THE LOW TO MID 70S.

FRI-MON...MID-LEVEL TROUGHING WILL ENCOMPASS THE EASTERN CONUS
DURING THIS TIME AS A LARGE RIDGE AMPLIFIES OVER THE WESTERN CONUS.
DEEP LAYER SOUTHWEST TO WEST-SOUTHWEST FLOW WILL BE DOMINANT THROUGH
THE PERIOD. SUFFICIENT MOISTURE...THE DAILY SEA BREEZE REGIME AND
VARIOUS OTHER AFTERNOON BOUNDARY COLLISIONS SHOULD ALLOW FOR A 40 TO
50 PERCENT CHANCE POP THROUGH THIS PERIOD. THE WESTERLY STEERING
FLOW...WHILE REMAINING LIGHT...WILL STILL PUSH STORMS TOWARDS THE
EAST COAST LATER IN THE DAY AND EVENING. SOME OF THESE STORMS WILL
MOVE OFF THE EAST COAST PRESENTING ISSUES FOR MARINERS. AFTERNOON
HIGHS AND OVERNIGHT LOWS IN LINE WITH NEAR SEASONAL CONDITIONS
THROUGH THE PERIOD.

&&

.AVIATION...
BRIEF...TOO SHORT EVEN FOR TEMPO...LOW CEILINGS IN THE LIGHT
SOUTHERLY FLOW UNTIL THE SLIGHTLY STRONGER WINDS ABOVE THE SURFACE
WORK THEIR WAY DOWN WITH DAYTIME HEATING. LOCAL WRF_ARW3 MODEL RUN
SUGGESTING MID TO LATE AFTERNOON...19Z-22Z...STORMS OVER THE
INTERIOR AND LITTLE EARLY AT THE COAST.

PREVIOUS AVIATION DISCUSSION
SCATTERED SHOWERS WITH IFR WILL AFFECT THE COAST EARLY THIS
MORNING BUT OTHERWISE VFR WILL OCCUR UNTIL SHOWERS/STORMS GET
GOING DURING THE LATE MORNING OR EARLY AFTERNOON ALONG THE EAST
COAST SEA BREEZE. THIS ACTIVITY MAY TEND TO LINGER NEAR THE COAST
WELL INTO THE AFTERNOON. THE STRONGEST BOUNDARY INTERACTIONS ARE
EXPECTED ACROSS THE INTERIOR DURING THE LATE AFTERNOON TO EARLY
EVENING. IN ADDITION TO ABOUT AN HOUR OF IFR IN HEAVY RAIN...A FEW
STORMS WILL AGAIN PRODUCE FREQUENT LIGHTNING STRIKES.

&&

.MARINE...

CURRENT-THIS AFTERNOON...
THE TWO NOAA BUOYS AT 20 AND 120NM OFFSHORE WERE RECORDING EAST TO
SOUTHEAST WINDS AROUND 5 KNOTS AND AROUND 15 KNOTS AND LONG PERIOD 3
TO 4 FOOT SEAS RESPECTIVELY. THE TWO SCRIPPS BUOYS AT 4 AND 6NM OFF
THE COAST WERE RECORDING 2 FOOT LONG PERIOD SEAS. SEA BREEZE MAY
BACK THE NEARSHORE WINDS MORE TO THE EAST DURING THE AFTERNOON.

MORNING UPDATE HAS NO SIGNIFICANT CHANGES.

PREVIOUS MARINE DISCUSSION

TODAY-TONIGHT...A SOUTHEAST BREEZE EARLY THIS MORNING IS FORECAST
TO VEER TO SOUTHERLY THROUGH THE DAY AND INTO TONIGHT. SPEEDS
LOOK TO BE 10 KNOTS OR LESS BUT REACHING 10-15 KNOTS OFFSHORE
TONIGHT. HIGH MOISTURE WILL RESULT IN SCATTERED NORTHWARD MOVING
SHOWERS AND STORMS THROUGH THE PERIOD.

WED-SAT...THE FAIRLY WEAK SURFACE PRESSURE GRADIENT CONTINUES EACH
DAY WITH FORECAST SEA BREEZE FORMATION AND MARCH INLAND EACH
AFTERNOON. WINDS AOB 10 KTS DURING THE DAYLIGHT PERIOD...EXCEPT NEAR
10-12 KTS NEAR THE COAST EACH AFTERNOON FOLLOWING SEA BREEZE
FORMATION. NOCTURNAL WINDS WILL KICK UP FOR A PERIOD OF NEAR 15 KTS
EACH EVENING AWAY FROM THE COAST. WIND DIRECTION WILL VARY FROM SSE
TO SSW. SEAS AOB 3 FT. THE MAIN MARINE CONCERN WILL CONTINUE TO BE
STORMS NEAR THE COAST/NEAR SHORE WATERS EACH AFTERNOON/EVENING AS
OVERALL MOISTURE REMAINS ELEVATED. WINDS/SEAS LOCALLY HIGHER INVOF
STORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  89  75  91  75 /  60  20  40  30
MCO  92  75  93  75 /  60  20  50  30
MLB  90  76  90  76 /  60  20  40  30
VRB  89  75  89  75 /  60  30  40  20
LEE  92  76  94  77 /  60  20  50  30
SFB  93  77  94  77 /  60  20  50  30
ORL  92  77  94  77 /  60  20  50  30
FPR  88  74  88  75 /  60  30  40  20

&&

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

$$

IMPACT WX...BRAGAW
PUBLIC SERVICE...CARTWRIGHT
FORECASTS...WIMMER




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