[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED DEC 08 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 ALONG 08N13W 05N37W 06N49W 05N53W. ISOLATED
MODERATE CONVECTION IS FROM 03N-09N BETWEEN 12W-21W...AND WITHIN
150 NM NORTH OF THE AXIS BETWEEN 21W-29W. WIDELY SCATTERED
MODERATE CONVECTION IS WITHIN 150 NM NORTH OF THE AXIS BETWEEN
45W-54W. THIS AREA OF CONVECTION IS ENHANCED BY THE EASTERN
PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 11N56W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 08/1500 UTC...A 1016 MB LOW IS CENTERED NEAR 27N93W WITH A
COLD FRONT TRAILING SOUTH FROM THE LOW ALONG 25N94W 22N96W TO
INLAND OVER MEXICO NEAR 20N97W. A WARM FRONT ALSO EXTENDS
EASTWARD FROM THE LOW ALONG 27N90W TO 28N87W. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING WITHIN 90 NM EAST OF THE COLD
FRONT...WHILE SCATTERED SHOWERS ARE OCCURRING WITHIN 120 NM
NORTH OF THE WARM FRONT. THIS FRONTAL SYSTEM IS SUPPORTED ALOFT
BY AN UPPER LEVEL SHORTWAVE TROUGH CURRENTLY PROGRESSING
EASTWARD ACROSS THE LOWER MISSISSIPPI RIVER VALLEY. THE SURFACE
LOW IS FORECAST TO MOVE SE OVER THE NEXT 24 HOURS AND POSITION
ITSELF OVER WESTERN CUBA BY EARLY THURSDAY. AS THE COLD FRONT
PUSHES EASTWARD...STRONG N TO NE WINDS ARE FORECAST IN WAKE OF
THE FRONT...BUT BY FRIDAY AS SURFACE RIDGING BUILDS BACK OVER
THE NW GULF...WINDS WILL VEER SOUTHERLY AHEAD OF THE NEXT COLD
FRONT FORECAST TO ENTER THE NW GULF WATERS BY LATE SATURDAY.

CARIBBEAN SEA...
WATER VAPOR IMAGERY INDICATES VERY DRY SOUTHWESTERLY FLOW ALOFT
IS LOCATED OVER THE NW CARIBBEAN EAST OF AN UPPER LEVEL
SHORTWAVE TROUGH SWEEPING QUICKLY ACROSS THE SE CONUS AND
NORTHERN GULF OF MEXICO. THIS SUBSIDENCE IS CONTINUING TO
PROVIDE GENERALLY FAIR CONDITIONS OVER THE NW CARIBBEAN...
CUBA...AND JAMAICA THIS AFTERNOON. FARTHER EAST...A SHEARLINE
MEANDERS FROM HISPANIOLA NEAR 19N72W TO 15N75W INTO A NEARLY
STATIONARY 1010 MB LOW CENTERED NEAR 10N80W. STRONGER NE WINDS
AND EASTERLY TRADES CONVERGE ALONG THE AXIS OF THE SHEAR LINE
AND INTO THE LOW PRESSURE CENTER PROVIDING FOCUS FOR SCATTERED
SHOWERS AND ISOLATED TSTMS WITHIN 150 NM EITHER SIDE OF A LINE
FROM 17N72W TO 09N80W. THIS AREA OF CONVECTIVE ACTIVITY LIES ON
THE WESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED IN
THE TROPICAL NORTH ATLC NEAR 11N56W. EAST OF THE SHEAR LINE...
LOW-LEVEL MOISTURE CONTINUES TO STREAM FROM THE CENTRAL ATLC
OVER THE EASTERN CARIBBEAN AND PROVIDE THE LESSER ANTILLES...
PUERTO RICO...AND EASTERN DOMINICAN REPUBLIC WITH ISOLATED
SHOWERS THROUGH THE REMAINDER OF THE AFTERNOON AND EVENING HOURS.

ATLANTIC OCEAN...
A DEEP LAYER TROUGH IS OVER THE WESTERN NORTH ATLC AND SUPPORTS
A PAIR OF FRONTAL BOUNDARIES ANALYZED INTO THE DISCUSSION AREA.
FIRST...A DISSIPATING STATIONARY FRONT ENTERS THE REGION NEAR
32N56W AND EXTENDS SW TO HISPANIOLA NEAR 20N70W. WHILE MOST OF
THE UPPER LEVEL SUPPORT FOR THIS FRONT REMAINS NORTH OF 29N...
ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE
BOUNDARY N OF 25N. WEST OF THE WANING STATIONARY FRONT...A COLD
FRONT ENTERS THE DISCUSSION AREA NEAR 32N61W THAT EXTENDS SW TO
NEAR 26N70W. NO SIGNIFICANT CONVECTION IS NOTED WITH THE COLD
FRONT...HOWEVER A 08/1416 UTC ASCAT PASS DEPICTED STRONGER NW
WINDS TO 25 KT N OF 29N BETWEEN THE FRONT AND 68W. FARTHER
EAST...AN UPPER LEVEL RIDGE AXIS EXTENDS ALONG 45W AND SUPPORTS
A SURFACE RIDGE WITH AXIS FROM 32N42W TO 20N55W THAT CONTINUES
TO PRODUCE FAIR CONDITIONS ACROSS MUCH OF THE CENTRAL ATLC
BETWEEN 30W-52W. OVER THE EASTERN ATLC...AN UPPER LEVEL TROUGH
IS EVIDENT ON WATER VAPOR IMAGERY WITH AXIS ALONG 26W DIPPING
SOUTHWARD TO 07N. THE UPPER LEVEL TROUGH SUPPORTS A 1005 MB LOW
CENTERED OVER THE MADEIRA ISLANDS NEAR 34N16W WITH A SURFACE
TROUGH ANALYZED FROM THE LOW TO 23N29W. ISOLATED SHOWERS
GENERALLY REMAIN N OF 27N BETWEEN 17W-27W.

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

$$
HUFFMAN




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