[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271115
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE DEC 27 2011

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
1100 UTC.

...ITCZ/MONSOON TROUGH...

A GREAT PORTION OF THE MONSOON TROUGH REMAINS INLAND OVER
AFRICA. A SMALL SECTION OF IT ENTERS THE ATLC THROUGH THE COAST
OF LIBERIA ALONG 6N10W AND QUICKLY ENDS AT 4N17W. THE ITCZ AXIS
EXTENDS WSW FROM THIS POINT ALONG 4N30W 3N40W TO THE COAST OF
BRAZIL NEAR 2N50W. SCATTERED WEAK TO MODERATE CONVECTION IS
WITHIN 70-100 NM ON EITHER SIDE OF THE ITCZ/MONSOON TROUGH AXIS.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL SHORTWAVE MOVING
ACROSS THE NW AND N CENTRAL GULF BASIN. THIS FEATURE SUPPORTS AN
OCCLUDED 1007 MB LOW CENTERED OVER WRN TENNESSEE WITH A COLD
FRONT ENTERING THE GULF ALONG 30N85W EXTENDING SW TO 24N90W THE
SOUTH TO THE SOUTHERN MEXICO COAST NEAR 18N93W. MOSAIC DOPPLER
RADAR IMAGERY INDICATES A FAST MOVING PRE-FRONTAL LINE OF HEAVY
SHOWERS AND THUNDERSTORMS MOVING ACROSS THE FAR NE GULF BASIN N
OF 26N. SCATTERED SHOWERS ARE OCCURRING WITHIN 50 NM EITHER SIDE
OF THE FRONT. A BROAD AREA OF OVERCAST LOW LEVEL STRATOCUMULUS
CLOUDS EXTENDS 120 NM W OF THE FRONT. WEST OF THE FRONT...GUSTY
NW WINDS IN THE RANGE OF 15 TO 25 KT ARE FORECAST TO CONTINUE
THROUGH THE MORNING HOURS AS HIGH PRESSURE ANCHORED OVER
NORTHERN MEXICO AND TEXAS BUILDS IN ACROSS THE WESTERN AND
CENTRAL GULF THROUGH LATE TUESDAY INTO WEDNESDAY.

CARIBBEAN SEA...
VERY DRY AIR ALOFT AND STRONG SUBSIDENCE COVERS MOST OF THE
CARIBBEAN WATERS THIS MORNING. THIS AIRMASS IS SUPPRESSING DEEP
CONVECTION ACROSS THE DISCUSSION AREA. FRESH TO STRONG TRADE
WIND FLOW CONTINUES ACROSS MUCH OF THE BASIN...ESPECIALLY
BETWEEN 68W-80W AND NEAR THE COAST OF COLOMBIA...WITH A FEW
SMALL CLUSTERS OF LOW-TOP WEAK SHOWERS EMBEDDED IN THE FLOW
INCLUDING COASTAL PORTIONS OF NORTHERN NICARAGUA...HONDURAS...
AND BELIZE. THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH
WEDNESDAY MORNING.

ATLANTIC OCEAN...
AN UPPER LEVEL SHORTWAVE/TROUGH MOVES ACROSS THE NW ATLC NORTH
OF THE DISCUSSION AREA SUPPORTING A COLD FRONT ANALYZED INTO THE
AREA ALONG 32N53W CONTINUING WSW ALONG 27N62W TO 26N71W...WHERE
LOW-LEVEL MOISTURE BECOMES MORE DIFFUSE AND A WEAK STATIONARY
FRONT CONTINUES WESTWARD INTO THE NW BAHAMAS ALONG 27N78W.
POSSIBLE ISOLATED SHOWERS ARE OCCURRING WITHIN 70 NM EITHER SIDE
OF THE FRONT. AN EARLIER ASCAT PASS DEPICTED STRONGER NORTHERLY
WINDS UP TO 30 KT NORTH OF THE FRONT EAST OF 70W. GALE FORCE
WINDS ARE N OF 30N WITHIN 240 NM E OF FRONT GENERATING SEAS 8 TO
12 FT. IN THE MEAN TIME...AN UPPER LEVEL RIDGE IS BUILDING
ACROSS THE WESTERN ATLC WITH DRY AIR ALOFT AND STRONG SUBSIDENCE
NOTICED ON WATER VAPOR IMAGERY. THIS FEATURE SUPPORTS A 1024 MB
HIGH CENTERED NEAR 34N70W. A WEAK AREA OF LOW LEVEL CONFLUENCE
OF LIGHT WINDS IS ANALYZED AS A WEAK SURFACE TROUGH FROM 20N47W
TO 14N50W WITHOUT ANY RAINSHOWER ACTIVITY ASSOCIATED. THE
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF AN UPPER
LEVEL LOW CENTERED NEAR 19N32W. A SIGNIFICANT AMOUNT OF MOISTURE
AND POSSIBLE SCATTERED SHOWERS AND TSTMS SUPPORTED BY STRONG
MIDDLE TO UPPER LEVEL DIFFLUENCE ARE LOCATED EAST OF THE UPPER
LOW FROM 10N-20N E OF 28W.

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

$$

GARCIA




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