[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120546
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST WED JAN 12 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ...

THE ITCZ AXIS IS ANALYZED FROM 5N8W 3N27W 2N43W 1N51W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM N OF THE
ITCZ BETWEEN 21W-26W WITH CLUSTERS OF SIMILAR CONVECTION WITHIN
120 NM S OF THE ITCZ BETWEEN 21W-29W AND WITHIN 60 NM OF LINE
FROM 6N34W TO 2N44W. CLUSTERS OF SCATTERED MODERATE CONVECTION
ARE FROM THE EQUATOR TO 5N BETWEEN 7W-14W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LOW IS OVER THE S GREAT LAKES REGION EXTENDING AN
UPPER TROUGH OVER THE E HALF OF THE CONUS INTO THE W ATLC
RESULTING IN WSW FLOW ALOFT OVER THE GULF. THIS UPPER TROUGH IS
TRAILING A COLD FRONT AT 12/0300 UTC INTO THE W ATLC ACROSS S
FLORIDA NEAR FORT LAUDERDALE TO S OF NAPLES INTO THE GULF ALONG
24N85W TO 22N93W. A SURFACE RIDGE CONTINUES TO BUILD OVER THE
CENTRAL PLAIN STATES INTO THE NW GULF ANCHORED BY A 1039 MB HIGH
OVER OKLAHOMA AND RESPONSIBLE FOR A RE-ENFORCING BOUNDARY THAT
EXTENDS ACROSS NE FLORIDA S OF JACKSONVILLE TO JUST N OF TAMPA
INTO THE GULF ALONG 26N88W TO 23N94W. THIS BOUNDARY IS MARKED BY
FALLING DEW POINTS AND REMARKABLY CLEAR SKIES TO THE N AND
OVERCAST LOW CLOUDS WITH ISOLATED SHOWERS TO THE S. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE INLAND OVER THE YUCATAN
PENINSULA AND INTO THE E BAY OF CAMPECHE S OF 22N BETWEEN
87W-92W. OVERCAST LOW CLOUDS WITH ISOLATED SHOWERS ARE OVER THE
W GULF W OF LINE FROM S OF GALVESTON TEXAS TO THE COAST OF
MEXICO NEAR 18N92W. THE FRONT IS EXPECTED TO EXIT THE GULF WED
NIGHT AS STRONG HIGH PRESSURE WILL PRODUCE FRESH TO STRONG N TO
NE WINDS THROUGH THU MORNING BEFORE GRADUALLY WEAKENING THROUGH
FRI.

CARIBBEAN SEA...
BROAD UPPER RIDGE COVERS THE CARIBBEAN WITH THE RIDGE AXIS
ANCHORED OVER THE SE CARIBBEAN NEAR 14N64W AND EXTENDS TO OVER
PORTIONS OF THE W AND CENTRAL ATLC. FRESH/STRONG TRADE WINDS
CONTINUE ACROSS THE CENTRAL AND E CARIBBEAN DUE TO THE TIGHT
PRESSURE GRADIENT OF THE LOWER PRESSURE OVER SOUTH AMERICA AND
THE SURFACE RIDGE OVER THE W ATLC INTO THE CENTRAL ATLC. THESE
TRADE WINDS ARE BANKING LOW CLOUDS ALONG THE MOUNTAINS OF W
PANAMA AND COSTA RICA GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS INLAND AND WITHIN 45 NM ALONG THE COAST S
OF 11N W OF 80W.  THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN
WITH FAIR WEATHER TONIGHT. A COLD FRONT WILL MOVE INTO THE NW
CARIBBEAN LATER THIS MORNING BRINGING FRESH NE WINDS THAT
GRADUALLY BECOME STRONG BY WED NIGHT.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE E US CONUS EXTENDS OVER THE W ATLC
SUPPORTING A COLD FRONT THAT ENTERS THE REGION AT 12/0300 UTC
NEAR 32N72W ACROSS FLORIDA AND INTO THE GULF OF MEXICO NEAR FORT
LAUDERDALE. THIS UPPER TROUGH IS BEING ABSORBED INTO THE BROAD
UPPER TROUGH THAT COVERS THE N/CENTRAL ATLC SUPPORTING A COLD
FRONT THAT ENTERS THE CENTRAL ATLC NEAR 32N38W TO 26N47W WHERE
IT DISSIPATES AS A STATIONARY FRONT TO 24N55W. SCATTERED SHOWERS
ARE WITHIN 75 NM E OF THE EASTERN MOST COLD FRONT. SURFACE HIGH
PRESSURE COVERS THE REMAINDER OF THE W ATLC ANCHORED BY A 1025
MB HIGH NEAR 28N61W. THE BROAD UPPER RIDGE THAT COVERS THE
CARIBBEAN EXTENDS OVER THE W ATLC INTO THE CENTRAL ATLC TO 27N
W OF 40W WITH STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT
COVERING AREA AND THUS LIMITING SHOWER ACTIVITY. A DEEP LAYERED
RIDGE COVERS THE E ATLC WITH THE UPPER LEVELS ANCHORED NEAR THE
CANARY ISLANDS AND A SURFACE 1032 MB HIGH 200 NM NNE OF THE
MADEIRA ISLANDS AND THUS PRODUCING FAIR WEATHER FOR THE ATLC E
OF FRONT.

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

$$
PAW



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