[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120551
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE JAN 13 2015

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURE...
A GALE WARNING IS IN EFFECT FOR THE SOUTH CENTRAL CARIBBEAN OFF
THE COAST OF COLOMBIA THIS AFTERNOON. THE STRONG PRESSURE
GRADIENT BETWEEN W ATLC HIGH PRESSURE AND THE RELATIVELY LOWER
PRESSURE OVER THE CARIBBEAN IS GENERATING STRONG TRADE WINDS
WHICH WILL PULSE TO GALE FORCE THROUGH EARLY AFTERNOON OFF THE
COAST OF COLOMBIA. PLEASE SEE THE LATEST NWS HIGH SEAS FORECAST
UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 7N11W TO 6N15W WHERE THE ITCZ BEGINS AND CONTINUES
ALONG 4N29W 5N47W TO SOUTH AMERICA NEAR 4N52W. CLUSTERS OF
ISOLATED MODERATE CONVECTION ARE FROM 3N-7N BETWEEN 30W-45W.

...DISCUSSION...

GULF OF MEXICO...
AN MID TO UPPER LEVEL TROUGH EXTENDS FROM THE
N TEXAS COAST TO THE SW GULF OF MEXICO. A STALLED FRONT REACHES
FROM WEAK 1019 MB LOW PRES JUST OF THE SABINE PASS NEAR 29N98W
TO THE SW GULF ALONG THE MEXICAN COAST NEAR 18N93W. THE UPPER
TROUGH IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS WITHIN
240 NM E OF THE FRONT NORTH OF 22N. MOIST LOW LEVEL SE FLOW
ACROSS THE FRONT IS SUPPORTING FORMATION OF WIDESPREAD LOW
CLOUDINESS ALONG THE COAST OF TEXAS AND OFF THE COAST OF
MEXICO...AS NOTED IN CURRENT SATELLITE IMAGERY ALONG WITH
OBSERVATIONS FROM COASTAL SITES AND OFFSHORE PLATFORMS. THE
UPPER TROUGH WILL MIGRATE EASTWARD THROUGH THE CENTRAL GULF
THROUGH LATE TODAY...ALLOWING THE FRONTAL BOUNDARY TO DRIFT
EASTWARD ACCORDINGLY ALONG WITH THE SCATTERED SHOWERS AND
THUNDERSTORMS. THE WEAK LOW OFF SABINE PASS WILL SHIFT INLAND
AND DISSIPATE THROUGH THIS MORNING. ANOTHER MID TO UPPER IMPULSE
WILL BRING A REINFORCING FRONT INTO THE NW GULF LATE MONDAY.

CARIBBEAN SEA...
AN ASCAT SATELLITE PASS FROM 0240 UTC ALONG WITH RECENT BUOY
OBSERVATIONS INDICATE FRESH TO STRONG TRADE WINDS FROM THE
TROPICAL N ATLC WATERS W OF 55W THROUGH THE EASTERN AND CENTRAL
CARIBBEAN. THE ASCAT PASS ALSO CONFIRMED WINDS TO GALE FORCE
ALONG THE COAST OF COLOMBIA BETWEEN CARTAGENA AND BARRANQUILLA.
THE GALES ARE BEING ENHANCED BY LOCAL OVERNIGHT DRAINAGE FLOW
AND ARE EXPECTED TO DIMINISH TO BELOW GALE FORCE LATER THIS
MORNING AFTER SUNRISE. THE FRESH TO STRONG TRADE WILL PERSIST
THROUGH EARLY THIS WEEK AS LONG AS THE HIGH PRES N OF THE AREA
PERSISTS. WAVE HEIGHTS AT BUOY 42058 IN THE CENTRAL CARIBBEAN
NEAR 15N74W ARE NEAR 11 FT...BUT SEAS TO 15 FT ARE LIKELY
ONGOING OFF COLOMBIA IN THE AREA OF GALES. LOW TO MID LEVEL
CLOUDINESS IS NOTED ALONG A WEAK SURFACE TROUGH IS NOTED ALONG
THE LEADING EDGE OF THE TRADE WIND SURFACE...SOUTHEAST OF
JAMAICA. A FEW SHOWERS ASSOCIATED WITH THIS WEAK TROUGH SHOWED
UP ON JAMAICA RADAR SOUTH OF THE ISLAND EARLIER THIS
EVENING...BUT HAVE SINCE DISSIPATED. ADDITIONAL QUICK PASSING
SHOWER ACTIVITY ASSOCIATED WITH TRADE WIND CONVERGENCE IS NOTED
ON GUADELOUPE AND MARTINIQUE RADAR IMAGERY AS WELL AS FARTHER
SOUTH INTO THE WINDWARD ISLANDS AS NOTED ON TRINIDAD RADAR.
TRADE WINDS...ALONG WITH SHOWERS ASSOCIATED WITH THE TRADE WIND
CONVERGENCE WILL DIMINISH BY MID WEEK AS HIGH PRES N OF THE AREA
WEAKENS AND SHIFTS EASTWARD.

...HISPANIOLA...
HIGH PRECIPITABLE WATER VALUES ASSOCIATED IN
PART WITH A LOW TO MID LEVEL TROUGH CURRENTLY PASSING SW OF
HAITI HAS BEEN SUPPORTING SCATTERED PASSING SHOWERS ACROSS THE
ISLAND SINCE YESTERDAY. SLIGHTLY DRIER CONDITIONS TO THE EAST OF
THE TROUGH WILL ALLOW SHOWER ACTIVITY TO DIMINISH ACROSS LEEWARD
FACING AREAS OF HISPANIOLA TO INCLUDE CENTRAL AND SOUTHERN HAITI
AND SOUTHERN DOMINICAN REPUBLIC. WINDWARD FACING AREAS ALONG
NORTHERN HAITI...DOMINICAN REPUBLIC AND THE NORTHEAST AND EASTERN
SLOPES OF THE CENTRAL MOUNTAINS WILL STILL SEE SOME TRADE WIND
RELATED LOW TOPPED CLOUDINESS AND A FEW SHOWERS THROUGH LATE
TODAY...ALTHOUGH OVERALL DIMINISHING.

ATLANTIC OCEAN...
A WEAK SURFACE TROUGH PERSISTS ALONG 70W FROM 24N TO 30N. THIS
FEATURE IS RELATED TO A NEGATIVELY TILTED UPPER TROUGH EXTENDING
FROM 28N67W TO 23N63W. A FEW SHOWERS ARE ONGOING NEAR THE BASE
OF THE UPPER TROUGH NEAR 24N65W...ALTHOUGH OVERALL CONVECTION
APPEARS MINIMAL AT THIS TIME. BUOY AND ASCAT SATELLITE DATA FROM
THE PAST SEVERAL HOURS INDICATES FRESH TO STRONG EASTERLY FLOW
ACROSS THE REGION W OF 55W. BUOYS SHOW SEAS OF MOSTLY 7 TO 8 FT
OUTSIDE OF THE BAHAMAS. ANOTHER SURFACE TROUGH IS NOTED OFF THE
NE COAST OF FLORIDA FROM NEAR ST AUGUSTINE TO NORTHEASTWARD TO
OFF THE SOUTH CAROLINA COAST NEAR HILTON HEAD. A FEW RELATED
SHOWERS ARE NOTED ON MELBOURNE FLORIDA RADAR MOVING ONSHORE NEAR
CAPE CANAVERAL. THE TROUGH WILL MOVE INLAND THIS MORNING AND
DISSIPATE.

ELSEWHERE E OF 55W...SHIP AND BUOY OBSERVATIONS ALONG WITH
MULTIPLE ASCAT AND RAPIDSCAT SATELLITE PASSES FROM THE PAST
SEVERAL HOURS INDICATE A LARGE AREA OF FRESH TO STRONG TRADE
WINDS S OF 20N TO THE ITCZ. AN UPPER CYCLONE REMAINS CENTERED NW
OF THE CAPE VERDE ISLAND NEAR 30N20W WITH AN UPPER TROUGH
REACHING SOUTHWESTWARD TO 18N45W...SUPPORTING MODEST CONVECTION
ALONG THE ITCZ E OF 45W. A SURFACE TROUGH ASSOCIATED WITH THE
UPPER FEATURE EXTENDS ALONG 30N/31N NEAR THE CANARY ISLANDS
SOUTHWARD INTO WESTERN MAURITANIA.

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

$$
CHRISTENSEN


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