[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED DEC 04 2013

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
2315 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR
07N12W TO 06N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 06N22W TO 06N32W TO 07N43W. SCATTERED MODERATE
CONVECTION AND TSTMS ARE FROM 01N-09N BETWEEN 13W-23W. ISOLATED
MODERATE CONVECTION AND TSTMS ARE FROM 05N-13N BETWEEN 25W-
40W.

...DISCUSSION...

GULF OF MEXICO...
WESTERLY TO NORTHWESTERLY MIDDLE TO UPPER LEVEL WIND FLOW IS
NOTED ON WATER VAPOR IMAGERY ASSOCIATED WITH AN ANTICYCLONIC
CIRCULATION CENTERED OVER THE SOUTHERN GULF NEAR 19N91W. MOSTLY
DRY AIR AND UPPER-LEVEL STABILITY SUPPORT FAIR WEATHER
CONDITIONS. AT THE SURFACE...SOUTHERLY RETURN FLOW IN THE RANGE
OF 10 TO 15 KT DOMINATES. OVER THE NORTHERN GULF...MOISTURE
ADVECTION FROM THE E PACIFIC BY THE ANTICYCLONE ALOFT AS WELL AS
UPPER-LEVEL DIFFLUENCE SUPPORT RAINSHOWERS N OF 28 BETWEEN 85W-
89W. ISOLATED SHOWERS ARE ALSO IN THE NW GULF N OF 27N W OF 94W.
A COLD FRONT CURRENTLY ANALYZED OVER THE SOUTHERN PLAINS IS
FORECAST TO MOVE SOUTHEASTWARD THROUGH LATE THURSDAY AND EMERGE
OFF THE TEXAS AND LOUISIANA COASTS BY EARLY TO MID-DAY FRIDAY
INTO SATURDAY.

CARIBBEAN SEA...
NORTH-NORTHWESTERLY DRY AND STABLE WIND FLOW IN THE MIDDLE
LEVELS IS NOTED W OF 70W ON WATER VAPOR IMAGERY WHICH CONTINUE
TO SUPPORT CLEAR SKIES AND FAIR WEATHER ACROSS THIS REGION OF
THE BASIN. OVER THE SW BASIN WITHIN 70 NM OF THE PANAMA CANAL
BETWEEN 78W-82W...SCATTERED SHOWERS ARE BEING ENHANCED BY THE
MONSOON TROUGH AXIS WHICH EXTENDS ACROSS NORTHERN PANAMA TO
NORTHERN COLOMBIA NEAR 06N74W. A MIDDLE TO UPPER LEVEL TROUGH
EXTENDS FROM NOVA SCOTIA SOUTHWARD TO THE EASTERN CARIBBEAN AND
SUPPORTS A SURFACE PRE-FRONTAL TROUGH CURRENTLY BEING ANALYZED
FROM 23N61W TO NE PUERTO RICO NEAR 18N65W TO S OF DOMINICAN
REPUBLIC NEAR 16N70W. AN ELONGATED MIDDLE TO UPPER LEVEL RIDGE
EXTENDS FROM THE CENTRAL ATLC TO THE LESSER ANTILLES TO GENERATE
DIFFLUENCE ALOFT AND SUPPORT RAINSHOWERS ACROSS DOMINICAN
REPUBLIC...MONA PASSAGE...PUERTO RICO...THE VIRGIN ISLANDS AND
NORTHERN LEEWARD ISLANDS. A WEAK PRESSURE GRADIENT ACROSS THE
BASIN IS FORECAST TO PROVIDE WITH TRADEWINDS IN THE RANGE OF 10-
15 KT THROUGHOUT THU MORNING. AFTERWARDS...A TIGHTER PRESSURE
GRADIENT IS EXPECTED TO DEVELOP SUPPORTING EASTERLY WINDS UP TO
20 KT ACROSS THE CENTRAL BASIN THROUGHOUT FRI NIGHT.

...HISPANIOLA...
A SURFACE TROUGH IS BEING ANALYZED FROM 23N61W IN THE ATLC TO NE
PUERTO RICO NEAR 18N65W TO S OF DOMINICAN REPUBLIC NEAR 16N70W.
THIS AREA OF LOW PRESSURE IS SUPPORTING RAINSHOWERS ACROSS
DOMINICAN REPUBLIC AND SOUTHERN ADJACENT WATERS TO 14N AS WELL
AS THE MONA PASSAGE. THE BOUNDARY IS FORECAST TO REMAIN
RELATIVELY STATIONARY OVER THE NEXT 24 HOURS AND GRADUALLY
DISSIPATE. HOWEVER RAINSHOWERS AND TSTMS ARE FORECAST TO PERSIST
ACROSS EASTERN PORTIONS OF THE ISLAND THROUGHOUT FRI NIGHT.

ATLANTIC OCEAN...
A BROAD MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM NOVA SCOTIA
SOUTHWARD TO THE EASTERN CARIBBEAN AND SUPPORTS A COLD FRONT
ANALYZED FROM 30N54W TO 25N60W TO 23N65W AS WELL AS A PRE-
FRONTAL TROUGH FROM 23N61W TO NE PUERTO RICO NEAR 18N65W TO S OF
DOMINICAN REPUBLIC NEAR 16N70W. AN ELONGATED MIDDLE TO UPPER
LEVEL RIDGE EXTENDS FROM THE CENTRAL ATLC TO THE LESSER ANTILLES
TO GENERATE DIFFLUENCE ALOFT AND SUPPORT SCATTERED MODERATE
CONVECTION/ISOLATED TSTMS N OF 24N BETWEEN 47W-60W AND WITHIN
260 NM E OF THE TROUGH AXIS FROM 18N-23N. THE REMAINDER OF THE
SW NORTH ATLC WEST OF THE COLD FRONT IS UNDER THE INFLUENCE OF
RELATIVELY DRY AND STABLE NORTHWESTERLY FLOW ALOFT AND A SURFACE
RIDGE ANCHORED BY A 1021 MB HIGH CENTERED OFF THE COAST OF THE
CAROLINAS NEAR 34N70W. A DEEP LAYERED LOW IS CENTERED OVER THE
EASTERN ATLC NEAR 31N28W WITH THE SURFACE LOW ANALYZED AT 996
MB. THE OCCLUDED LOW HAS A TRIPLE POINT IN THE VICINITY OF THE
MADEIRA ISLANDS NEAR 34N18W WITH A WARM FRONT STRETCHING SE TO
31N14W AND A DISSIPATING COLD FRONT EXTENDING SW FROM THE TRIPLE
POINT TO 21N28W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING MAINLY
WITHIN 240 NM OF THE LOW CENTER.

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

$$
RAMOS


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