[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122338
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAR 12 2014

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2230 UTC.

...SPECIAL FEATURES...
A COLD FRONT EXTENDS FROM 30N91W NEAR NEW ORLEANS LOUISIANA SW
TO 24N98W NEAR LA PESCA MEXICO. STRONG TO NEAR GALE FORCE
NORTHERLY WINDS WITH FREQUENT GUSTS TO GALE FORCE CAN BE FOUND
WEST OF THE FRONT. THE FRONT IS FORECAST TO SWEEP SOUTHWARD
ALONG THE MEXICAN COAST. GALES WILL DIMINISH IN THE NW GULF THIS
EVENING AND SHIFT TO ALONG THE COAST OF VERACRUZ THROUGH EARLY
THU MORNING. AT THE SAME TIME...THE FRONT WILL MOVE INTO THE SW
NORTH ATLC WITH GALE FORCE NW WINDS BEHIND THE FRONT. GALE
CONDITIONS WILL DIMINISH AS THE FRONT MOVES TO 31N72W TO 23N80W
NEAR NORTHERN CUBA JUST AFTER SUNRISE THU. SEE THE LATEST NWS
HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC
FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 06N11W TO
03N14W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
03N14W TO THE EQUATOR AT 21W. ISOLATED MODERATE CONVECTION IS
SOUTH OF 04N BETWEEN 12W-18W. SCATTERED MODERATE IS SOUTH OF 01N
BETWEEN 23W AND 27W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR
IMAGERY FROM THE NORTH CAROLINA COAST TO THE NORTHERN BAHAMAS.
THIS TROUGH IS RAPIDLY MOVING NE AHEAD OF A BROAD TROUGH
AMPLIFYING OVER THE MISSISSIPPI VALLEY. AT THE SURFACE...THE
SHORTWAVE SYSTEM IS FORCING A TROUGH THAT EXTENDS OVER THE
FORECAST AREA FROM NEAR JACKSONVILLE FLORIDA TO JUST NORTH OF
THE YUCATAN PENINSULA NEAR 23N88W. MEANWHILE...THE BROAD TROUGH
ALOFT IS REFLECTING A STRONG SURFACE COLD FRONT THAT HAS BROUGHT
GALE CONDITIONS TO THE NW GULF OF MEXICO. PLEASE SEE THE SPECIAL
FEATURES SECTION FOR DETAILS CONCERNING THE GALE CONDITONS.
PRECIPITABLE WATER IMAGERY SHOWS THAT MOISTURE IS CONVERGED
AHEAD OF THE SURFACE TROUGH...LEAVING RELATIVELY DRY CONDITONS
TO THE WEST NEAR THE COLD FRONT. RADAR IMAGERY SHOWS A LINE OF
SHOWERS OVER CENTRAL FLORIDA FROM 26N-29N AHEAD OF THE
TROUGH...WITH LIGHTNING FOUND WITHIN 75 NM SE OF THE TAIL OF THE
TROUGH NORTH OF THE YUCATAN CHANNEL. IN THE FORECAST
PERIOD...THE BROAD UPPER TROUGH AND ITS ASSOCIATED COLD FRONT
WILL OVERTAKE THE SHORTWAVE SYSTEM AND ITS ASSOCIATED SURFACE
TROUGH OVERNIGHT TONIGHT. AS THE FRONT SWEEPS SOUTHEASTWARD
THROUGH THURSDAY...N-NE WINDS ARE FORECAST TO REMAIN IN THE 20
TO 30 KT RANGE...GRADUALLY DIMINISHING LATE THURSDAY INTO FRIDAY
AS HIGH PRESSURE BUILDS INTO THE BASIN FROM THE SOUTHERN PLAINS.
THE HIGH WILL SHIFT EASTWARD ALONG 30N/31N FRIDAY INTO SATURDAY
WITH SOUTHERLY RETURN FLOW ESTABLISHING ITSELF ACROSS PORTIONS
OF THE WESTERN GULF.

CARIBBEAN SEA...
CONDITIONS ACROSS THE CARIBBEAN REMAIN RELATIVELY TRANQUIL.
WATER VAPOR IMAGERY SHOWS VERY DRY AIR ALOFT IMPLYING SUBSIDENT
CONDITONS OVER THE BASIN. AN UPPER LEVEL RIDGE FROM NE VENEZUELA
TO NICARAGUA WILL REMAIN IN PLACE THROUGH FRI. ISOLATED TRADE
WIND SHOWERS CAN BE FOUND IN MUCH OF THE AREA...WITH MORE
SCATTERED SHOWERS FOUND IN THE FAR EASTERN CARIBBEAN FROM 13N-
16N EAST OF 66W TO THE ISLANDS AND IN THE SW CARIBBEAN FROM 10N-
15N BETWEEN 79W AND 82W. WINDS AT THE SURFACE ARE RELATIVELY
WEAK ACROSS THE CARIBBEAN ON THE SOUTHWESTERN PERIPHERY OF A
SURFACE RIDGE STEMMING FROM HIGH PRES IN THE CENTRAL ATLC. THE
RIDGING TO THE NORTHEAST OF THE BASIN IS FORECAST TO SHIFT E-NE
AHEAD OF A COLD FRONT THAT WILL MOVE INTO THE NW CARIBBEAN EARLY
THURSDAY. MOISTURE IS CURRENTLY POOLED AHEAD OF A PRE-FRONTAL
TROUGH FOUND JUST NORTH OF THE YUCATAN CHANNEL. SCATTERED
THUNDERSTORMS CURRENTLY ACCOMPANYING THIS TROUGH SHOULD MOVE
INTO THE NORTHWEST CARIBBEAN OVERNIGHT TONIGHT AND ARE EXPECTED
NEAR THE FRONT AS IT MOVES INTO THE NORTHWEST CARIBBEAN. THE
FRONT WILL REACH FROM NEAR HAVANA CUBA TO CHETUMAL MEXICO THU
MORNING AND FROM MANZANILLO CUBA TO BELIZE CITY FRI MORNING.
OTHERWISE...FAIR WEATHER CONDITIONS SHOULD REMAIN RELATIVELY
UNCHANGED FOR THE NEXT FEW DAYS.

...HISPANIOLA...
SCATTERED SHOWERS ARE CLUSTERED CLOSE TO THE MOUNTAIN RANGES
OVER HISPANIOLA...WITH LIGHT WINDS PREVENTING THEM FROM STRAYING
FAR FROM THE AREA OF GREATEST OROGRAPHIC ENHANCEMENT.
ELSEWHERE...MOSTLY CLEAR SKIES AND FAIR CONDITIONS ARE NOTED ON
VISIBLE SATELLITE IMAGERY. THE HIGH PRESSURE OVER THE CENTRAL
ATLC THAT IS PRODUCING THE LIGHT E-SE WINDS WILL SLIDE EAST
THROUGH EARLY THU AS A FRONTAL BOUNDARY MOVES ACROSS THE SW
NORTH ATLC AND NW CARIBBEAN WATERS. THE FRONT WILL BEGIN TO
IMPACT HISPANIOLA FRI AS MOISTURE POOLED AHEAD OF THE FRONT
BEGINS TO INCREASE THE PROBABILITY OF PRECIPITATION. THE FRONT
IS EXPECTED TO WEAKEN AS IT REACHES THE WINDWARD PASSAGE FRI
EVENING.

ATLANTIC OCEAN...
THE AFOREMENTIONED SHORTWAVE TROUGH STRETCHING FROM THE NORTH
CAROLINA COAST TO THE NORTHERN BAHAMAS IS PROVIDING INSTABILITY
TO THE MOISTURE POOLED AHEAD OF ITS ASSOCIATED SURFACE TROUGH
WHICH IS STRETCHED FROM JACKSONVILLE TO FORT MYERS FLORIDA.
SCATTERED THUNDERSTORMS ARE NOTED PRIMARILY NORTH OF 29N BETWEEN
75W AND 78W. IN THE FORECAST PERIOD...THE BROAD UPPER TROUGH AND
ITS ASSOCIATED COLD FRONT WILL OVERTAKE THE SHORTWAVE SYSTEM AND
ITS ASSOCIATED SURFACE TROUGH OVERNIGHT TONIGHT. SEE THE SPECIAL
FEATURES SECTION FOR DETAILS ON THE GALE CONDITONS EXPECTED
BEHIND THE COLD FRONT NORTH OF 30N ENDING AROUND SUNRISE THU.
THE FRONT WILL CONTINUE EASTWARD...STRETCHING FROM BERMUDA TO
THE CENTRAL BAHAMAS THU EVENING AND FROM 32N55W TO THE WINDWARD
PASSAGE BY FRI EVENING. SHOWERS AND THUNDERSTORMS WILL ACCOMPANY
THE FRONT. TO THE EAST...AN UPPER LEVEL LOW NORTH OF THE AREA
NEAR 40N35W EXTENDS A TROUGH INTO THE CENTRAL PORTION OF THE
FORECAST AREA AND REFLECTS A COLD FRONT AT THE SURFACE FROM
32N33W TO 27N40W THEN BECOMING A STATIONARY FRONT TO 20N56W.
WIDELY SCATTERED SHOWERS ARE OCCURRING WITHIN 150 NM SOUTHEAST
OF THE FRONT...WITH SHOWERS BECOMING MORE NUMEROUS EAST OF 40W
WHERE THE FRONT BECOMES A COLD FRONT. THE REMAINDER OF THE SW
NORTH ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE CURRENTLY
STEMMING FROM 1021 MB HIGH PRES CENTERED NEAR 31N48W. THIS RIDGE
IS BISECTED BY THE FRONT OVER THE CENTRAL ATLC. THIS FRONT IS
EXPECTED TO WEAKEN AND SHIFT NORTH OF THE AREA OVER THE NEXT TWO
DAYS. THE REMAINING RIDGE WILL DRIVE MODERATE TRADE WINDS.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
SCHAUER


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