[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 121129
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURE...
A GALE WARNING REMAINS IN EFFECT FOR THE SOUTH CENTRAL CARIBBEAN
OFF THE COAST OF COLOMBIA THROUGH 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 TO THE COAST OF LIBERIA
NEAR 06N11W AND INTO THE E TROPICAL ATLC NEAR 05N16W WHERE THE
ITCZ BEGINS AND CONTINUES TO SOUTH AMERICA NEAR THE AMAZON RIVER
DELTA AT 00N50W. SCATTERED MODERATE CONVECTION IS NOTED FROM
04N TO 06N BETWEEN 24W AND 32W.

...DISCUSSION...

GULF OF MEXICO... AN MID TO UPPER LEVEL TROUGH EXTENDS FROM THE
LOUISIANA COAST TO OFF THE WEST COAST OF THE YUCATAN PENINSULA.
A STALLED FRONT REACHES FROM WEAK 1019 MB LOW PRES JUST OFF THE
SABINE PASS NEAR 29N92W TO THE SW GULF ALONG THE MEXICAN COAST
NEAR 18N93W. ANOTHER STALLED FRONTAL BOUNDARY EXTENDS EASTWARD
FROM THE LOW PRES TO THE COAST OF FLORIDA NEAR CRYSTAL RIVER.
THE UPPER TROUGH IS SUPPORTING SCATTERED SHOWERS AND A FEW
THUNDERSTORMS OFF THE NORTH COAST OF THE YUCATAN PENINSULA...AND
OVER THE NE GULF FROM THE MOUTH OF THE MISSISSIPPI RIVER TO THE
WESTERN FLORIDA PANHANDLE. SCATTERED SHOWERS AND THUNDERSTORM
HAVE DEVELOPED ALSO OVER THE SE GULF JUST WEST OF THE FLORIDA
KEYS. MOIST LOW LEVEL SE FLOW ACROSS THE FRONT IS SUPPORTING
FORMATION OF WIDESPREAD OVERCAST 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 SLIGHTLY ACCORDINGLY ALONG
WITH THE SCATTERED SHOWERS. THE WEAK LOW OFF SABINE PASS WILL
SHIFT INLAND AND DISSIPATE THROUGH LATE THIS MORNING. ANOTHER
MID TO UPPER IMPULSE WILL BRING A REINFORCING FRONT INTO THE NW
GULF LATE MONDAY.

CARIBBEAN SEA...
CURRENT BUOY OBSERVATIONS AND RECENT ASCAT SATELLITE DATA
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 SAN JUAN...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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