[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130553 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT DEC 13 2008

...CORRECTION FOR CURRENT SURFACE ANALYSIS TIME AND IMAGERY
TIME...

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.

...THE ITCZ...
THE ITCZ IS CENTERED ALONG 8N13W 4N30W 4N54W. A SURFACE TROUGH
IS EMBEDDED WITHIN THE ITCZ ALONG 56W S OF 14W. CYCLONIC
CURVATURE IS EVIDENT IN THE LOW CLOUDS ALONG THE TROUGH AXIS.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-6N
BETWEEN 3W-8W. SIMILAR CONVECTION IS FROM 3N-9N BETWEEN 27W-36W.

...DISCUSSION...

GULF OF MEXICO...
A COOLER AND DRIER AIRMASS IS ACROSS THE GULF REGION IN THE WAKE
OF A SURFACE COLD FRONT THAT EXTENDS FROM THE W ATLC ACROSS WRN
CUBA TO THE NE TIP OF THE YUCATAN PENINSULA NEAR 22N88W. THE
INCREASED SURFACE PRESSURE GRADIENT IN THE VICINITY OF THIS COLD
FRONT IS SUPPORTING NORTHERLY SURFACE WINDS OF 20 TO 25 KT
ACROSS PORTIONS OF THE E GULF. BROKEN TO OVERCAST STRATOCUMULUS
CLOUDS COVER THE SRN HALF OF THE GULF S OF 25N...INCLUDING THE
ERN BAY OF CAMPECHE AND THE YUCATAN PENINSULA DUE TO THE COLD
AIR ADVECTION OVER RELATIVELY WARM WATERS. MODERATE TO STRONG
SUBSIDENCE IN STRONG W-NW FLOW ALOFT IS INHIBITING ANY DEEP
CONVECTION ACROSS THE GULF REGION. A SURFACE RIDGE EXTENDS
ACROSS THE WRN GULF...ANCHORED BY A 1028 MB SURFACE HIGH THAT
DOMINATES MOST THE GULF. LOOKING AHEAD...EXPECT RETURN SOUTHERLY
FLOW TO INCREASE ACROSS THE WRN GULF SAT THROUGH LATE SUN AS LOW
PRESSURE DEVELOPS AND MOVES THROUGH THE CENTRAL U.S. PLAINS.

CARIBBEAN SEA...
A COLD FRONT OVER THE W ATLC ENTERS THE CARIBBEAN SEA THROUGH
ERN CUBA THEN CONTINUES SOUTH AS A STATIONARY FRONT THROUGH
18N80W TO COSTA RICA NEAR 10N83W. SCATTERED SHOWERS ARE ALONG
AND WITHIN 90 NM ON EITHER SIDE OF THIS FRONT. BEHIND THE
FRONT...A COOLER AND DRIER AIRMASS IS ACROSS THE NW CARIBBEAN...
WRN AND CENTRAL CUBA AND NRN CENTRAL AMERICA WHERE BROKEN TO
OVERCAST CLOUDINESS WITH EMBEDDED LIGHT SHOWERS ARE OBSERVED.
THE REMAINDER OF THE CARIBBEAN SEA REMAINS UNDER THE INFLUENCE
OF A STRONG 1040 MB HIGH PRESSURE SYSTEM CENTERED W OF THE
AZORES. PATCHES OF LOW LEVEL MOISTURE USHERED IN ON MODERATE TO
FRESH TRADE WINDS CONTINUE TO MOVE WWD ON THE SW PERIPHERY OF
THE SURFACE HIGH. SATELLITE IMAGERY REVEALS LARGEST AREA OF LOW
TOPPED SHOWERS S OF JAMAICA FROM 13N-16N BETWEEN 71W-80W MOVING
W-SW E OF THE STATIONARY FRONT. ALOFT...A RIDGE EXTENDS FROM N
COLOMBIA ACROSS CENTRAL AMERICA TO SE MEXICO.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH OVER THE ERN CONUS SUPPORTS A PAIR OF
COLD FRONTS OVER THE W ATLC. THE MAIN FRONT ENTERS THE FORECAST
AREA NEAR 32N70W AND CONTINUES SW OVER THE CENTRAL BAHAMAS TO
ERN CUBA NEAR 21N77W. THE SECONDARY FRONT EXTENDS FROM 31N75W
ACROSS THE NW BAHAMAS AND INTO THE STRAITS OF FLORIDA AND SE
GULF OF MEXICO. A PRE-FRONTAL TROUGH WITH A BAND OF SCATTERED
SHOWERS AND ISOLATED TSTMS IS WITHIN 150 NM E OF THE MAIN
BOUNDARY N OF 26N. THE REMAINDER OF THE ATLC IS UNDER THE
INFLUENCE OF A STRONG 1039 MB SURFACE HIGH CENTERED E OF THE
AZORES NEAR 37N38W. SUBSIDENCE AROUND THIS HIGH IS GENERALLY
SUPPORTING FAIR WEATHER CONDITIONS ACROSS MUCH OF THE ERN ATLC.
HOWEVER...AN UPPER-LEVEL TROUGH WITH AXIS ALONG 32N56W TO 17N48W
IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 22N-27N BETWEEN
45W-53W. THIS SURFACE HIGH IS ALSO GENERATING A WIDE SWATH OF
MODERATE TO STRONG ELY WINDS ACROSS THE BASIN PARTICULARLY FROM
21N-29N E OF 50W. BY EARLY NEXT WEEK...COMPUTER MODELS ARE
ANTICIPATING THE DEVELOPMENT OF A LOW PRESSURE SYSTEM OVER THE
TROPICAL CENTRAL ATLC AS THE UPPER LEVEL DEEP LAYERED TROUGH
CURRENTLY OVER THE ERN CONUS MOVES EWD.

$$
HUFFMAN






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