[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260545
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST MON DEC 26 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0530 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH REMAINS INLAND OVER AFRICA. THE ITCZ AXIS
EXTENDS WSW FROM THE COAST OF GUINEA NEAR 10N14W ALONG 5N25W
2N37W TO EQ50W. SCATTERED MODERATE CONVECTION IS FROM 3N-8N
BETWEEN 26W-35W.

...DISCUSSION...

GULF OF MEXICO...
SW FLOW ALOFT COVERS THE ENTIRE GULF THIS EVENING. THIS UPPER
LEVEL FLOW PATTERN IS MOVING MIDDLE TO UPPER LEVEL MOISTURE
NORTHEASTWARD ACROSS THE NRN AND ERN HALF OF THE GULF. WITHIN
THIS REGION OF MOISTURE ALOFT...A STATIONARY FRONTAL BOUNDARY
IS ANALYZED FROM 29N85W TO 28N92W THEN SOUTH TO THE COAST OF
MEXICO NEAR 18N93W. VISIBLE NIGHT CHANNEL AND IR WINDOW SHOW A
BROAD LAYER OF LOW LEVEL STRATOCUMULUS CLOUDS W OF THE FRONT TO
THE MEXICO AND TEXAS COAST W OF 92W WITH A FEW ISOLATED SHOWERS
OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONT S OF 28N92W.
MOSAIC DOPPLER RADAR INDICATES SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS N OF THE FRONT BETWEEN 84W-90W AFFECTING THE
COASTAL WATERS OF MISSISSIPPI...ALABAMA...AND THE FLORIDA
PANHANDLE. SURFACE RIDGING WILL RETURN TO THE WRN GULF OVER THE
NEXT FEW DAYS.

CARIBBEAN SEA...
VERY DRY AIR ALOFT AND STRONG SUBSIDENCE COVERS MOST OF THE
CARIBBEAN WATERS THIS EVENING. 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...WITH A FEW SMALL CLUSTERS OF LOW-TOP WEAK
SHOWERS EMBEDDED IN THE FLOW. THESE CONDITIONS ARE EXPECTED TO
PERSIST THROUGH TUESDAY MORNING.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE IS ACROSS MUCH OF THE WESTERN ATLC W OF 45W
WITH VERY DRY AIR ALOFT NOTICED ON WATER VAPOR IMAGERY. THIS
FEATURE SUPPORTS A 1024 MB HIGH CENTERED NEAR 30N70W. SLICING
THROUGH THE SURFACE RIDGE IS A WEAK COLD FRONT ANALYZED FROM
32N50W TO 27N57W TO 26N64W WHERE LOW-LEVEL MOISTURE BECOMES MORE
DIFFUSE AND A DISSIPATING COLD FRONT EXTENDS TO 27N70W. THIS
FRONT IS GENERATING POSSIBLE ISOLATED SHOWERS WITHIN 30 NM
EITHER SIDE OF IT. TO THE EAST OF THE FRONT...AN EARLIER ASCAT
PASS REVEALED AN AREA OF LOW LEVEL CONFLUENCE OF LIGHT WINDS
ANALYZED AS A WEAK SURFACE TROUGH FROM 32N44W TO 23N47W WITHOUT
ANY ACTIVITY ASSOCIATED. A SIMILAR SURFACE TROUGH IS ALSO
ANALYZED FROM 21N43W TO 10N49W. FARTHER EAST...AN UPPER LEVEL
LOW IS CENTERED NEAR 21N40W. THIS SYSTEM IS GENERATING A BROAD
AREA OF DIFFLUENCE FLOW ALOFT THAT COVERS THE ERN ATLC S OF 25N
E OF 38W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
ARE IN THIS REGION...WITH NE WINDS UP TO 25 KT.

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

$$

GARCIA




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