[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112358
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE MAR 11 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 IS FORECAST TO MOVE INTO THE NORTHWESTERN GULF OF
MEXICO EARLY WEDNESDAY. WINDS ARE EXPECTED TO GUST TO GALE FORCE
BEHIND THE FRONT NW OF A LINE FROM 29N91W TO 24N97W THROUGH WED
AFTERNOON UNTIL SUSTAINED GALE FORCE WINDS MATERIALIZE BEHIND
THE FRONT ALONG THE COAST OF VERACRUZ FROM 20N TO 24N W OF 95W
EARLY WED EVENING. GALE FORCE WINDS ARE FORECAST TO DIMINISH BY
SUNRISE THU.

THE SAME COLD FRONT IS FORECAST TO INDUCE GALE FORCE WINDS IN
THE SOUTHWEST NORTH ATLC. WEST TO NORTHWEST WINDS BEHIND THE
FRONT N OF 29N WILL PICK UP TO MINIMAL GALE FORCE BY EARLY THU
MORNING AND CONTINUE N OF 29N WITHIN 240 NM WEST OF THE FRONT AS
IT MOVES TO 32N71W TO THE STRAITS OF FLORIDA SUNRISE THU...
DIMINISHING BELOW GALE FORCE BY THU AFTERNOON.

SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS ON BOTH OF THESE GALE
WIND EVENTS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 07N11W TO
01N16W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
01N16W TO THE EQUATOR AT 18W. ISOLATED MODERATE CONVECTION IS S
OF 06N E OF 27W TO THE ITCZ/MONSOON TROUGH.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY OVER NORTHERN
LOUISIANA AND IS DRAGGING A WEAKENING TROUGH EASTWARD OVER THE
NORTH CENTRAL GULF OF MEXICO. THIS SYSTEM REFLECTS A TROUGH AT
THE SURFACE FROM SOUTHERN LOUISIANA INTO THE WEST CENTRAL GULF.
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE OCCURRING N OF 24N
BETWEEN 84W AND 92W INCLUDING INLAND PORTIONS OF COASTAL
MISSISSIPPI...ALABAMA AND FLORIDA. THE LOW IS EXPECTED TO
CONTINUE ON A N-NE TRACK AND GRADUALLY BECOME EMBEDDED WITHIN
SOUTHWESTERLY FLOW AT THE SURFACE AHEAD OF THE NEXT COLD FRONT
EXPECTED TO EMERGE OFF THE TEXAS AND LOUISIANA COAST BY EARLY
WEDNESDAY. SEE THE SPECIAL FEATURES SECTION FOR DETAILS ON THE
GALE CONDITIONS EXPECTED BEHIND THE FRONT.

CARIBBEAN SEA...
A STATIONARY FRONT IS ANALYZED FROM THE CENTRAL ATLC TO EASTERN
PUERTO RICO WHERE ISOLATED SHOWERS ASSOCIATED WITH THE BOUNDARY
ARE OCCURRING. ELSEWHERE...ONLY A FEW AREAS OF ISOLATED SHOWERS
CAN BE FOUND WITH THE MOST CONCENTRATED AREA OF SHOWERS NOTED
BETWEEN HAITI AND JAMAICA. THE OVERALL LACK OF SHOWER ACTIVITY
IS DUE TO UPPER LEVEL RIDGING EXTENDING FROM THE BAHAMAS THROUGH
EASTERN CUBA TO NW VENEZUELA NEAR 11N70W. THE UPPER LEVEL RIDGE
IS GENERALLY PROVIDING STABILITY AND DRY AIR OVER THE BASIN.
WINDS AT THE SURFACE ARE RELATIVELY WEAK ACROSS THE
CARIBBEAN...WITH A 1017 MB HIGH IN THE SW NORTH ATLC EAST OF THE
BAHAMAS NEAR 26N69W DRIVING THE FLOW. WINDS HAVE SHIFTED
SOUTHEASTERLY IN THE NW CARIBBEAN ON THE WEST SIDE OF THE
HIGH...WHILE THE STRONGEST TRADE WINDS ARE EXPECTED TO OCCUR
CLOSE TO THE COAST OF COLOMBIA IN THE EARLY MORNING HOURS WHEN
THE PRESSURE GRADIENT IS THE STRONGEST. THE HIGH TO THE NORTH OF
THE BASIN WILL SHIFT E-NE AHEAD OF A COLD FRONT EXPECTED TO MOVE
INTO THE GULF OF MEXICO WEDNESDAY. THE STATIONARY BOUNDARY
NORTHEAST OF PUERTO RICO WILL DISSIPATE AS A RESULT. THE COLD
FRONT WILL BRING AN INCREASED CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE NW CARIBBEAN BY LATE WED AFTERNOON AND
CONTINUING INTO THU. THE FRONT IS EXPECTED TO REACH FROM CENTRAL
CUBA TO THE GULF OF HONDURAS BY THU AFTERNOON.

...HISPANIOLA...
THE AFOREMENTIONED WEAK WINDS OVER THE CARIBBEAN HAVE ALLOWED A
SEABREEZE TO PUSH INLAND FROM THE COAST OVER HISPANIOLA. VISIBLE
SATELLITE IMAGERY SHOWS CLOUDS ACCUMULATED WHERE THE SEABREEZE
HAS MET THE WINDWARD SLOPES. PRECIPITABLE WATER IMAGERY SHOWS
DRIER AIR IN PLACE OVER THE DOMINICAN REPUBLIC N OF THE MIDDLE
LEVEL TROUGH SUPPORTING THE STATIONARY BOUNDARY NE OF PUERTO
RICO COMPARED TO HAITI WHERE AN AREA OF SHOWERS IS PASSING TO
THE SOUTH. THE CHANCE OF RAIN SHOULD DIMINISH SOMEWHAT TOMORROW
AS THIS MIDDLE LEVEL TROUGH DISSIPATES...BUT WILL INCREASE ON
THU AS THE COLD FRONT MOVES INTO THE NORTHWESTERN CARIBBEAN AND
MOISTURE AHEAD OF IT BECOMES MORE PLENTIFUL.

ATLANTIC OCEAN...
THE SW NORTH ATLC REGION REMAINS FAIRLY TRANQUIL THIS EVENING.
WEAK 1017 MB HIGH PRES REMAINS EAST OF THE BAHAMAS NEAR 26N69W
AND A STATIONARY FRONT STRETCHES FROM 32N37W TO EASTERN PUERTO
RICO. SCATTERED SHOWERS CAN GENERALLY BE FOUND WITHIN 120 NM
EITHER SIDE OF THE TROUGH E OF 50W AND MORE ISOLATED SHOWERS ARE
MAINLY WITHIN 120 NM S OF THE FRONT W OF 50W. A BROAD MIDDLE TO
UPPER LEVEL TROUGH EVIDENT ON WATER VAPOR IMAGERY OVER THE
CENTRAL ATLC IS SUPPORTING THE STATIONARY FRONT AT THE SURFACE.
A 120 KT UPPER JET IS PUSHING INTO THE SOUTHERN PORTION OF THE
TROUGH. THIS IS ALLOWING THE SURFACE STATIONARY FRONT TO BEGIN
TO WEAKEN W OF 50W. THE BROAD TROUGH ALOFT WILL BE SQUEEZED
EASTWARD AS A NEW BROAD TROUGH AMPLIFIES OVER THE CENTRAL U.S.
AND PROMOTES RIDGING AHEAD OF IT OVER THE WESTERN AND CENTRAL
ATLC WED AND THU. THE LINGERING ENERGY ASSOCIATED WITH THE
STATIONARY FRONT WILL WEAKEN AND BECOME CAUGHT IN THE SOUTHERLY
FLOW AHEAD OF THE NEW TROUGH ON THU. THIS TROUGH WILL SEND A
STRONG COLD FRONT INTO THE SW NORTH ATLC EARLY THU...WITH GALE
FORCE WINDS EXPECTED BEHIND THE FRONT. SEE THE SPECIAL FEATURES
SECTION FOR DETAILS ON THIS GALE EVENT. OTHERWISE...THE
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A
SURFACE RIDGE FROM 32N27W TO 20N40W TO SAINT LUCIA.

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

$$
SCHAUER


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