[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272355
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU MAR 27 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
2300 UTC.

...SPECIAL FEATURES...
A STRONG PRESSURE GRADIENT EXISTS ACROSS THE SW CARIBBEAN SEA
BETWEEN STRONG HIGH PRESSURE CENTERED ACROSS THE SW NORTH ATLC
AND LOWER PRESSURE ACROSS THE NORTHWESTERN SOUTH AMERICAN
CONTINENT. WINDS ALONG THE COAST OF COLOMBIA ARE FORECAST TO
CONTINUE TO PULSE TO GALE FORCE IN THE EARLY MORNING HOURS WHEN
THE PRESSURE GRADIENT IS STRONGEST. GALE FORCE NE TO EAST WINDS
ARE EXPECTED TO OCCUR FROM 11N-13N BETWEEN 74W-77W EARLY FRIDAY
AS WELL AS EARLY SAT. SEE 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 07N13W TO
02N22W TO 01N29W THEN ITCZ TO THE EQUATOR NEAR 36W. SCATTERED
MODERATE WITH ISOLATED STRONG CONVECTION IS SOUTH OF THE MONSOON
TROUGH TO 01N BETWEEN 11W-17W.

...DISCUSSION...

GULF OF MEXICO...
WEST-SOUTHWESTERLY...ALMOST ZONAL...FLOW IS NOTED ALOFT OVER THE
GULF OF MEXICO THIS EVENING. WATER VAPOR IMAGERY INDICATES THE
SUBTROPICAL JET STREAM IS ADVECTING MOISTURE AND CLOUDINESS FROM
THE EASTERN PACIFIC OVER NORTHEASTERN MEXICO ACROSS THE NORTHERN
GULF TO THE FLORIDA PENINSULA. LAND-BASED RADAR IMAGERY SHOWS
SHOWERS FROM 26N-28N ACROSS THE FLORIDA PENINSULA AND IN THE
COASTAL WATERS AND TSTMS IN THE COASTAL WATERS OFF SE LOUISIANA.
LIGHTNING DATA ALSO SHOWS TSTMS IN THE CENTRAL GULF FROM 26N-27N
BETWEEN 87W-93W. THIS PRECIPITATION IS OCCURRING IN THE
SOUTHWESTERN PERIPHERY OF A SURFACE RIDGE ANCHORED BY STRONG
1033 MB HIGH PRESSURE JUST OFF THE COAST OF CAPE HATTERAS. SE
WINDS DOMINATE THE FLOW ACROSS THE GULF OF MEXICO...WITH FRESH
TO STRONG SE WINDS FOUND N OF 24N W OF 87W AS WELL AS FROM 22N-
25N W OF 87W...INCLUDING WITHIN THE STRAITS OF FLORIDA. ASCAT
PASSES FROM 1526 UTC AND 1622 UTC CONFIRM THESE CONDITIONS. THE
AREA OF FRESH TO STRONG WINDS IS EXPECTED TO SHRINK WESTWARD
OVER THE NEXT 24 HOURS AND DIMINISH BELOW A STRONG BREEZE BY
EARLY SAT MORNING WHEN A COLD FRONT IS FORECAST TO MOVE INTO THE
NORTHWESTERN GULF. A FRESH NORTHERLY BREEZE WILL GRADUALLY BUILD
BEHIND THE FRONT SAT AS IT MOVES SOUTH THROUGH THE WESTERN
GULF...LYING FROM THE FLORIDA PANHANDLE TO THE BAY OF CAMPECHE
BY SAT AFTERNOON.

CARIBBEAN SEA...
WEST TO NORTHWESTERLY FLOW ALOFT IS OVER THE CARIBBEAN BASIN
WITH WATER VAPOR IMAGERY INDICATING RELATIVELY DRY AIR AND A
SUBSIDENT ENVIRONMENT IN PLACE THIS EVENING...ESPECIALLY SOUTH
OF 15N. AT THE SURFACE...A SHEAR LINE WAS ANALYZED FROM THE
NORTHWESTERN DOMINICAN REPUBLIC THROUGH HAITI AND ALONG 19N EAST
OF 80W. THE 1528 UTC ASCAT PASS SHOWS FRESH TO STRONG EASTERLY
WINDS IN THE LEE OF CUBA NORTH OF THE SHEAR LINE...WITH ONLY A
MODERATE BREEZE AT BEST TO ITS SOUTH. WINDS WILL GRADUALLY
DIMINISH TO A MODERATE BREEZE HERE THROUGH EARLY SATURDAY
MORNING. ISOLATED SHOWERS ARE MAINLY OCCURRING WITHIN 120 NM
SOUTH OF THE SHEAR LINE...WITH TSTMS FOUND OVER SOUTHWESTERN
JAMAICA. FARTHER SOUTH...A GALE WARNING IN EFFECT FOR THE
SOUTHERN CARIBBEAN WATERS OFF THE COAST OF COLOMBIA. THE STRONG
PRESSURE GRADIENT CREATED BETWEEN HIGH PRESSURE CENTERED ACROSS
THE SW NORTH ATLC AND LOWER PRESSURE ACROSS THE NORTHWESTERN
SOUTH AMERICAN CONTINENT IS EXPECTED TO RELAX SOMEWHAT BY
SATURDAY AS THE HIGH PRESSURE MOVES EASTWARD. SEE THE SPECIAL
FEATURES SECTION ABOVE FOR DETAILS.

...HISPANIOLA...
CURRENTLY...A SHEAR LINE IS ANALYZED FROM 20N70W TO
19N75W...FROM THE NORTHWESTERN DOMINICAN REPUBLIC THROUGH HAITI
AND ALONG 19N. THIS SHEAR LINE IS PROVIDING A FOCUS FOR ISOLATED
SHOWERS ACROSS MUCH OF THE ISLAND WEST OF 70W...INCLUDING THE
NORTHERN ADJACENT COASTAL WATERS. SHOWERS HAVE CLUSTERED NEAR
THE WINDWARD SLOPES OF THE HIGH TERRAIN THIS EVENING. THE SHEAR
LINE WILL GRADUALLY DISSIPATE OVER THE NEXT 24 HOURS...WITH THE
AREA OF LOW LEVEL CONVERGENCE EXPECTED TO LIFT NORTH OF THE
ISLAND. SHOWERS OVER HISPANIOLA SHOULD BECOME SLIGHTLY LESS
LIKELY AS THE BEST MOISTURE CONVERGENCE MOVES AWAY FROM THE
ISLAND.

ATLANTIC OCEAN...
MOSTLY ZONAL WESTERLY FLOW IS NOTED ON WATER VAPOR IMAGERY OVER
THE SW NORTH ATLC WEST OF 60W WHERE AN 80-100 KT SUBTROPICAL JET
IS IN PLACE THIS EVENING. SHOWERS ARE CLUSTERED OVER THE FLORIDA
PENINSULA AND IN THE COASTAL WATERS FROM 26N-28N SOUTH OF THE
JET AXIS...WITH MORE ISOLATED TRADE WIND SHOWERS FOUND PRIMARILY
SOUTH OF 26N. AT THE SURFACE...1033 MB HIGH PRESSURE JUST
OFFSHORE OF CAPE HATTERAS...WITH A RIDGE AXIS EXTENDING
SOUTHEASTWARD TO NEAR 27N60W...IS DRIVING THE EAST-SOUTHEASTERLY
FLOW ACROSS THE BAHAMAS. THIS HIGH PRESSURE LIES IN THE WAKE OF
A COLD FRONT STRETCHED FROM 31N51W THROUGH 20N70W TO THE
NORTHWESTERN DOMINICAN REPUBLIC. VISIBLE AND INFRARED IMAGERY
SHOW COLD AIR STRATOCUMULUS BEHIND THE FRONT EAST OF THE
BAHAMAS. AN ASCAT-B PASS FROM 1440 UTC REVEALED FRESH TO STRONG
NW WINDS BEHIND THE FRONT NORTH OF THE RIDGE AXIS AND FRESH TO
STRONG NE WINDS SOUTH OF THE RIDGE AXIS EAST OF THE BAHAMAS.
ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 120 NM EITHER
SIDE OF THE FRONT N OF 27N AND ISOLATED SHOWERS WITHIN 60 NM
EITHER SIDE OF THE FRONT SOUTH OF 27N. OTHERWISE...THE REMAINDER
OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED BY A 1033 MB HIGH CENTERED NORTH OF THE
AZORES NEAR 43N31W.

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

$$
SCHAUER


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