000
AXNT20 KNHC 232354
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST THU DEC 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 05N09W 03N27W CROSSING THE EQUATOR 
NEAR 45W THEN OVER NE BRAZIL NEAR 01S48W. WIDELY SCATTERED 
MODERATE CONVECTION IS FROM 03S TO 04N BETWEEN 24W-39W...AND 
FROM 02S TO 07N BETWEEN 39W-47W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES MAINLY ZONAL WESTERLY UPPER LEVEL 
FLOW DOMINATES OVER THE GULF THIS EVENING WITH RELATIVELY DRY 
AIR AND SUBSIDENCE NOTED IN THE MIDDLE TO UPPER LEVELS. 
HOWEVER...NEAR THE SURFACE AS OF 23/2100 UTC...A WEAK COLD FRONT 
ENTERS THE SE GULF THROUGH THE FLORIDA STRAITS AND TRANSITIONS 
TO A STATIONARY FRONT MEANDERING ALONG 24N83W 26N90W TO INLAND 
OVER SOUTH TEXAS NEAR 28N97W. THIS VERY WEAK BOUNDARY BRIDGES 
STRONGER SURFACE RIDGING TO THE NORTH OVER THE SE CONUS AND 
WEAKER RIDGING OVER THE SW GULF AND PORTIONS OF EAST-CENTRAL 
MEXICO. MOSTLY CLEAR SKIES AND FAIR CONDITIONS ACCOMPANY THE 
RIDGING WHILE ISOLATED SHOWERS ARE POSSIBLE WITHIN 30 NM EITHER 
SIDE OF THE FRONTAL BOUNDARY. THIS FRONT WILL CONTINUE TO BECOME 
MORE DIFFUSE THROUGH THE NEXT 24 HOURS. LOOKING AHEAD TO THE 
WEEKEND...A VIGOROUS UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING 
EASTWARD ACROSS THE DESERT SOUTHWEST WITH LOW PRESSURE FORECAST 
TO DEVELOP ALONG THE FRONT AND DEEPEN AS IT TRACKS EAST THROUGH 
SUNDAY ALONG THE COASTAL PLAIN. A COLD FRONT DRAPED SW FROM THE 
LOW CENTER WILL INTRODUCE STRONG NORTHERLY WINDS OVER MUCH OF 
THE GULF BY EARLY SUNDAY.

CARIBBEAN SEA...
DRY AIR AND SUBSIDENCE ALOFT IS NOTED ON WATER VAPOR IMAGERY 
OVER THE NW CARIBBEAN DUE TO ZONAL WESTERLY FLOW N OF 16N W OF 
75W. SURFACE RIDGING ALSO EXTENDS FROM THE SOUTH-CENTRAL GULF OF 
MEXICO ACROSS THE YUCATAN PENINSULA AND INTO THE NW CARIBBEAN 
FURTHER ENHANCING FAIR CONDITIONS THIS EVENING. FARTHER EAST 
HOWEVER...MOIST SOUTHWESTERLY FLOW ALOFT IS LOCATED ON THE 
WESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION 
CENTERED IN THE TROPICAL NORTH ATLC NEAR 10N50W. THIS GENERAL 
UPPER LEVEL DIFFLUENT ENVIRONMENT IS ENHANCING CONVECTION 
FOCUSED ALONG A SET OF SURFACE TROUGHS ANALYZED OVER THE SW AND 
EASTERN CARIBBEAN. THE FIRST SURFACE TROUGH EXTENDS FROM 15N80W 
TO A 1011 MB LOW NEAR 11N80W THEN TO THE COAST OF NORTHERN 
COLOMBIA NEAR 09N77W. OVERALL CLIMATOLOGICAL CYCLONIC SURFACE 
FLOW ACROSS THE SW CARIBBEAN AND CONVERGENT TRADE WINDS ARE 
GENERATING ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF A LINE 
FROM 14N72W TO 13N80W...AND POSSIBLE ISOLATED SHOWERS S OF 16N W 
OF 80W. THE OTHER TWO SURFACE TROUGHS ARE POSITIONED OVER THE 
EASTERN CARIBBEAN...ONE ANALYZED FROM 16N64W TO 12N70W AND THE 
OTHER EXTENDS FROM A WEAK 1011 MB LOW NEAR 17N55W ACROSS 
DOMINICA TO NEAR 13N63W. WIDELY SCATTERED SHOWERS AND ISOLATED 
TSTMS ARE OCCURRING S OF 17N E OF 69W IN ASSOCIATION WITH THESE 
TWO BOUNDARIES.

ATLANTIC OCEAN...
A RATHER LARGE AND BROAD DEEP LAYER TROUGH REMAINS ANCHORED IN 
THE WESTERN AND CENTRAL NORTH ATLC BY A 968 MB LOW CENTERED SE 
OF NEWFOUNDLAND NEAR 45N48W THAT CONTINUES TO EXTEND INFLUENCE 
OVER MUCH OF THE SW NORTH ATLC AND CENTRAL ATLC TO 22N W OF 35W. 
IMPULSES OF MID-LEVEL ENERGY CONTINUE TO ROTATE AROUND THE MAIN 
LOW COMPLEX WITH A PAIR OF COLD FRONTS ENTERING THE DISCUSSION 
AREA. ONE COLD FRONT ENTERS THE SW NORTH ATLC NEAR 32N58W AND 
EXTENDS SW ALONG 26N70W TO THE FLORIDA STRAITS NEAR 24N80W. THE 
FRONT EXHIBITS A RELATIVE LACK OF ANY DEEP CONVECTION...HOWEVER 
POSSIBLE ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE 
FRONT BETWEEN 55W-72W...WHICH CLOSELY RELATES TO THE STRONGEST 
MID-LEVEL FORCING. FARTHER EAST...THE SECOND COLD FRONT ENTERS 
THE REGION NEAR 32N29W AND EXTENDS SW TO A WEAK 1011 MB LOW 
CENTERED NEAR 17N55W. A SURFACE TROUGH THEN TRAILS SW FROM THE 
LOW TO THE WINDWARD ISLANDS. ISOLATED SHOWERS ARE WITHIN 90 NM 
EITHER SIDE OF THE FRONT. SOUTH OF THE WEAK LOW ALONG 55W...A 
SURFACE TROUGH IS ANALYZED FROM 06N-12N ALONG 57W SUPPORTING 
ISOLATED SHOWERS WITHIN 120 NM WEST OF THE TROUGH AXIS. THE 
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A 
SURFACE RIDGE ANCHORED BY A 1015 MB HIGH CENTERED NEAR 21N33W.

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

$$
HUFFMAN