[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111129
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI DEC 11 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.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS ALONG SW AFRICA FROM 06N AND THE
PRIME MERIDIAN TO SOUTHERN LIBERIA...ENTERING THE ATLC NEAR
06N10W. AT THIS POINT...THE INTERTROPICAL CONVERGENCE ZONE
BEGINS AND EXTENDS TO 04N20W TO 04N30W TO 03N43W. A TROUGH IS
JUST TO THE WEST AND EXTENDS FROM 08N45W TO THE EQUATOR AT 46W.
SCATTERED MODERATE CONVECTION IS FROM 04N-07N BETWEEN 22W-28W.
ISOLATED SHOWERS ARE NEAR THE TROUGH AXIS.

...DISCUSSION...

GULF OF MEXICO...

A 1018 MB HIGH PRES LOCATED OVER THE NE GULF NEAR 29N85W EXTENDS
A RIDGE ACROSS THE REGION PRODUCING MAINLY A GENTLE TO MODERATE
ANTICYCLONIC WIND FLOW AND GENERALLY FAIR WEATHER. SOUTHERLY
RETURN FLOW IN THE 15-20 KT RANGE IS ALREADY NOTED ACROSS THE NW
GULF. THE HIGH PRES WILL SHIFT NE INTO THE ATLANTIC OCEAN DURING
THE NEXT 24 HOURS KEEPING A RIDGE ACROSS THE GULF WATERS. THE
PRESSURE GRADIENT WILL INCREASE OVER THE WESTERN GULF BETWEEN
THE HIGH OVER THE ATLC AND A DEVELOPING LOW PRESSURE ACROSS THE
CENTRAL UNITED STATES. THE RESULT COULD BE FRESH TO STRONG
SOUTHERLY WINDS OVER MUCH OF THE WESTERN HALF OF THE GULF BY SAT
AFTERNOON. WINDS WILL FURTHER INCREASE TO 25-30 KT EARLY ON SUN
JUST AHEAD OF THE NEXT COLD FRONT FORECAST TO ENTER THE GULF BY
SUN MORNING. FRESH TO STRONG NORTHERLY WINDS AND BUILDING SEAS
ARE EXPECTED IN THE WAKE OF THE FRONT ON SUN. ALOFT...A MID TO
UPPER LEVEL TROUGH EXTENDS FROM CENTRAL FLORIDA ACROSS WESTERN
CUBA INTO THE FAR NW CARIBBEAN. NW WINDS AND MODERATE TO STRONG
SUBSIDENCE IS NOTED BEHIND THE TROUGH ACROSS MOST OF THE GULF
WHILE STRONG SOUTHWESTERLY WINDS ARE AHEAD OF THE TROUGH AXIS.
THESE WINDS ARE TRANSPORTING ABUNDANT MID-UPPER LEVEL MOISTURE
ACROSS SOUTHERN MEXICO...INCLUDING THE BAY OF CAMPECHE...AND THE
NW CARIBBEAN INTO CUBA AND THE BAHAMAS AS NOTED ON WATER VAPOR
IMAGERY.

CARIBBEAN SEA...

THE AFOREMENTIONED MID TO UPPER LEVEL TROUGH IS RESPONSIBLE FOR
THE GROWTH OF CONVECTION ACROSS PARTS OF EASTERN CUBA...THE
CAYMAN ISLANDS AND JAMAICA. LIGHTNING DATA ALSO INDICATE SOME
ACTIVE WEATHER ACROSS THIS REGION. THIS TROUGH ALOFT IS FORECAST
TO SHIFT EASTWARD EXTENDING ACROSS CENTRAL CUBA TODAY AND ACROSS
EASTERN CUBA ON SAT. AS A RESULT...ABUNDANT MOISTURE AND THE
FOCUS FOR CONVECTION WILL PERSIST OVER PARTS OF EASTERN
CUBA...THE CAYMAN ISLANDS AND JAMAICA THIS FRI...WITH THESE
CONDITIONS EXTENDING OVER HISPANIOLA MAINLY DURING THE UPCOMING
WEEKEND. LOCALLY HEAVY RAIN AND GUSTY WINDS MAY OCCUR IN
ASSOCIATION WITH THIS ACTIVE WEATHER. PATCHES OF LOW LEVEL
MOISTURE EMBEDDED IN THE TRADE WIND FLOW ARE NOTED ACROSS THE
REMAINDER OF THE BASIN...MORE CONCENTRATED OVER THE WINDWARD
ISLANDS AND THE EASTERN CARIBBEAN...PARTICULARLY E OF 65W. THE
ATLC HIGH PRES LOCATED NE OF THE AREA CONTINUES TO PRODUCE FRESH
TO STRONG TRADE WINDS ACROSS THE SOUTH-CENTRAL CARIBBEAN. RECENT
SCATTEROMETER PASSES CONFIRMED THE PRESENCE OF THESE WINDS.
MODERATE TO FRESH WINDS DOMINATE THE REMAINDER OF THE CENTRAL
CARIBBEAN WITH GENTLE TO MODERATE WINDS ELSEWHERE. THIS WEATHER
PATTERN WILL PERSIST THROUGH THE WEEKEND.

...HISPANIOLA...

AS PREVIOUSLY MENTIONED...AN APPROACHING MID-UPPER LEVEL TROUGH
FROM THE WEST WILL INCREASE THE LIKELIHOOD OF RAIN ACROSS
HISPANIOLA LATER TODAY THROUGH LIKELY SUN. UPPER DIFFLUENCE
AHEAD OF THE TROUGH WILL SUPPORT THE DEVELOPMENT OF SHOWER WITH
EMBEDDED TSTMS AND GUSTY WINDS ACROSS PARTS OF THE ISLAND.

ATLANTIC OCEAN...

CONVECTION IS ON INCREASE ACROSS THE BAHAMAS AND REGIONAL WATERS
DUE TO UPPER DIFFLUENCE AHEAD OF THE ABOVE MENTIONED MID-UPPER
LEVEL TROUGH. A SURFACE TROUGH HAS DEVELOPED VERY CLOSE TO SE
FLORIDA IN RESPONSE TO THIS PERSISTENT ACTIVE WEATHER. MOSAIC
DOPPLER RADAR FROM THE SE U.S. INDICATES SCATTERED SHOWERS AND
TSTMS ALONG THE SURFACE TROUGH THAT EXTENDS FROM 28N79W ALONG
THE COAST OF SE FLORIDA INTO THE UPPER FLORIDA KEYS AND THE
STRAITS OF FLORIDA TO NEAR THE COAST OF WESTERN CUBA AT 23N83W.
CONVECTION IS FORECAST TO CONTINUE OVER THE BAHAMAS AND REGIONAL
WATERS AS THE UPPER TROUGH SHIFTS EASTWARD TODAY AND SAT. ON
THIS DAY...ANOTHER LOW-LEVEL TROUGH IS EXPECTED TO DEVELOP E OF
THE BAHAMAS LIKELY ALONG THE TAIL END OF A COLD FRONT THAT
CURRENTLY EXTENDS FROM 31N61W TO THE CENTRAL BAHAMAS. THIS WILL
BE ANOTHER FACTOR THAT WILL ENHANCE THE SHOWER AND TSTM ACTIVITY
ACROSS THE BAHAMAS AND ADJACENT WATERS. THE COLD FRONT IS
ATTACHED TO A GALE CENTER LOCATED E OF BERMUDA NEAR 32N61W.
ANOTHER COLD FRONT IS MOVING INTO THE FORECAST AREA FROM THE N
AND STRETCHES FROM 31N38W TO 29N45W TO 31N53W. A BAND OF MAINLY
LOW CLOUDS IS ASSOCIATED WITH THE FRONT. THE REMAINDER OF THE
ATLC IS UNDER THE INFLUENCE OF A RIDGE ANCHORED BY A 1023 MB
HIGH LOCATED NEAR 26N46W. THIS SYSTEM WILL SHIFT SE AS THE GALE
CENTER DEEPENS AND MOVES MAINLY EASTWARD.

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

$$
GR
This weather bulletin was brought to you by:
www.nashvilleweather.net