[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111750
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT DEC 11 2010

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N14W 07N24W 05N33W 04N45W 03N51W.
A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ANALYZED FROM
05N26W TO 12N21W AND IS LIKELY REFLECTIVE OF AN UPPER LEVEL
TROUGH OVER THE EASTERN ATLC. NUMEROUS SHOWERS AND SCATTERED
TSTMS ARE OCCURRING WITHIN THE AREA BOUNDED BY 04N10W TO 05N31W
TO 19N17W TO 04N10W. EARLIER MORNING WINDSAT AND ASCAT PASSES
SHOWED THE PRESENCE OF THE SURFACE TROUGH WITH STRONG N-NE WINDS
TO 30 KT ALONG THE W AFRICA COAST FROM 10N-18N BETWEEN 16W-23W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE EXTENDS ACROSS THE GULF FROM THE BIG BEND REGION
OF FLORIDA TO OVER THE YUCATAN PENINSULA THAT CONTINUES TO
PROVIDE OVERALL FAIR AND STABLE CONDITIONS FOR THE ENTIRE BASIN
THIS AFTERNOON. FURTHERMORE...WATER VAPOR IMAGERY CONFIRMS A DRY
AND STABLE AIRMASS IS IN PLACE WITH MAINLY WESTERLY ZONAL FLOW
LOCATED ALOFT. AS THE SURFACE RIDGE SLIDES EASTWARD OVER THE
NEXT 24 HOURS...STRONGER S-SW WINDS UP TO 30 KT ARE EXPECTED
OVER THE NW AND NORTH-CENTRAL GULF WATERS TO PRECEDE THE NEXT
COLD FRONT FORECAST TO ENTER THE NW GULF WATERS LATE TONIGHT
INTO EARLY SUNDAY. AS THE FRONT PUSHES SOUTHEASTWARD DURING THE
DAY ON SUNDAY...STRONG NORTHERLY WINDS TO 30 KT ARE EXPECTED
WEST OF THE COLD FRONT.

CARIBBEAN SEA...
DRY AIR AND OVERALL SUBSIDENCE IN MAINLY W-SW FLOW ALOFT COVERS
THE NW CARIBBEAN MAINTAINING FAIR CONDITIONS THIS AFTERNOON.
WHILE AN UPPER LEVEL ANTICYCLONE REMAINS OVER NORTHERN SOUTH
AMERICA...WEAK UPPER LEVEL SHORTWAVE TROUGHING IS LOCATED OVER
THE CENTRAL CARIBBEAN ALONG 70W THAT SUPPORTS A SHEAR LINE
ANALYZED FROM CENTRAL HISPANIOLA NEAR 18N71W ALONG 15N77W INTO A
1010 MB LOW CENTERED NEAR 09N78W. LOW-LEVEL MOISTURE CONTINUES
TO POOL WITHIN 120 NM EITHER SIDE OF THE SHEAR LINE WITH DEEPER
CONVECTION LOCATED WITHIN 90 NM OF THE LOW CENTER OVER THE SW
CARIBBEAN AND PORTIONS OF EASTERN PANAMA. THE SHEAR LINE
SEPARATES STRONG NORTHERLY FLOW TO THE WEST...AND GENERALLY
LIGHTER TRADES TO THE E. THE REMAINDER OF THE BASIN EAST OF THE
SHEAR LINE BOUNDARY IS EXPERIENCING MOSTLY FAIR CONDITIONS...
HOWEVER A FEW ISOLATED SHOWERS EMBEDDED WITHIN LOW-LEVEL
MOISTURE ARE POSSIBLE S OF 14N BETWEEN 63W-73W...INCLUDING THE
ABC ISLANDS.

ATLANTIC OCEAN...
A VERY WEAK UPPER LEVEL SHORTWAVE TROUGH IS EVIDENT ON WATER
VAPOR IMAGERY OFF THE COAST OF NE FLORIDA THAT SUPPORTS A
SURFACE TROUGH BOUNDARY ANALYZED FROM THE CENTRAL BAHAMAS NEAR
24N76W ALONG 27N79W 30N79W TO BEYOND 32N80W. LOW-LEVEL
CONVERGENCE IS STRONGEST EAST OF THE TROUGH AXIS WITH ISOLATED
SHOWERS OCCURRING N OF 27N BETWEEN 75W-79W AND WITHIN 30 NM
EITHER SIDE OF THE SURFACE TROUGH S OF 27N. FARTHER EAST OVER
THE REMAINDER OF THE W ATLC...A 1010 MB LOW IS CENTERED NEAR
26N64W THAT IS EMBEDDED WITHIN MOSTLY DRIER W-SW FLOW ALOFT. A
WEAK SURFACE TROUGH EXTENDS SW FROM THE LOW CENTER TO CENTRAL
HISPANIOLA NEAR 18N71W. ISOLATED SHOWERS ARE OCCURRING WITHIN
120 NM EITHER SIDE OF THE BOUNDARY. TO THE NE OF THE LOW...A
TRAILING AND GRADUALLY DISSIPATING STATIONARY FRONT IS ANALYZED
FROM THE LOW CENTER ALONG 30N57W TO 31N49W. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING FROM 26N-32N BETWEEN 53W-63W...
HOWEVER...MOST CONVECTION CONTINUES TO EXPERIENCE A GREAT DEAL
OF WESTERLY SHEAR AND THEREFORE ARE RELATIVELY SHORT-LIVED IN
DURATION. ANOTHER LINE OF LOW-LEVEL SHOWERS...OCCURRING ALONG A
LINE OF SPEED CONVERGENCE IS FOUND WITHIN 120 NM EITHER SIDE OF
A LINE FROM 14N50W TO 18N56W TO 26N55W. FINALLY...OVER THE
EASTERN ATLC...A SHARP UPPER LEVEL TROUGH EXTENDS INFLUENCE FROM
OFF THE COAST OF EUROPE TO WEST OF THE CANARY ISLANDS TO 10N39W.
A SURFACE TROUGH RESULTS FROM THE DEEP LAYER TROUGH ANALYZED
INTO THE DISCUSSION AREA NEAR 32N21W TO 23N27W. ISOLATED SHOWERS
ARE FROM 26N TO 32N BETWEEN 16W AND THE SURFACE TROUGH AXIS. THE
REMAINDER OF THE ATLC E OF 50W IS CONTROLLED BY A SURFACE RIDGE
ANCHORED BY A 1021 MB HIGH CENTERED NEAR 27N39W.

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

$$
HUFFMAN




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