000
AXNT20 KNHC 220541
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
105 AM EST SAT JAN 22 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 0530 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED FROM THE COAST OF SIERRA LEONE NEAR 
8N13W CONTINUING SW ALONG 3N20W CROSSING THE EQUATOR NEAR 30W TO 
THE COAST OF BRAZIL ALONG 1S40W 4S44W. WEAK SCATTERED SHOWERS 
ARE WITHIN 50 NM ON EITHER SIDE OF THE AXIS BETWEEN 20W-30W. 
MODERATE TO HEAVY SHOWERS AND ISOLATED THUNDERSTORMS ARE W OF 
35W S OF 1N.

...DISCUSSION...

THE GULF OF MEXICO...
A COLD FRONT IS ACROSS THE WEST ATLC AND ENTERS THE FAR SE BASIN 
FROM THE SOUTHERN FLORIDA PENINSULA SW TO THE YUCATAN PENINSULA 
ALONG 26N81W 24N85W 21N88W. A LONGWAVE UPPER TROUGH MOVING OFF 
THE EASTERN CONUS SEABOARD SUPPORTS THE COLD FRONT. SATELLITE 
IMAGERY SHOWS NO CONVECTION IN THE VICINITY OF THE FRONT...AS 
MOST OF THE CONVECTION HAS NOW MOVED INTO THE NW CARIBBEAN AND 
WEST ATLC DURING THE PAST SEVERAL HOURS. AS THE FRONT MOVES OUT 
OF THE GULF...COLD AIR ADVECTION TAKES PLACE ACROSS THE AREA 
WITH NORTHERLY WINDS UP TO 15 KT. THIS FLOW WILL CONTINUE AS 
SURFACE RIDGE BUILDS OVER THE NW AND N CENTRAL BASIN OVER THE 
NEXT 24 HOURS.

THE CARIBBEAN SEA...
PRE-FRONTAL SHOWERS AND ISOLATED THUNDERSTORMS ARE ENTERING THE 
FAR NW BASIN N OF 20N W OF 83W...AS A COLD FRONT MAKES ITS WAY 
INTO THE BASIN. THIS FRONT IS EXPECTED TO CONTINUE TO EXPAND 
EAST ACROSS THE WESTERN CARIBBEAN WITH CONVECTION OVER THE NEXT 
24 HOURS. A PAIR OF WEAK SURFACE TROUGHS ARE ANALYZED OVER THE 
CENTRAL BASIN. THE FIRST ONE ALONG 75W FROM 13N-18N...AND THE 
SECOND ONE ALONG 69W FROM 13N-17N. SCATTERED SHOWERS ARE WITHIN 
90 NM ON EITHER SIDE OF BOTH SYSTEMS. COMPUTER MODELS SUGGEST 
THESE TWO SYSTEM WILL CONTINUE TO DRIFT WESTWARD OVER THE NEXT 
24 HOURS. OTHERWISE...MOSTLY FAIR WEATHER IS ELSEWHERE ACROSS 
THE AREA...DUE TO A DRY AND STABLE AIR MASS COVERING THE BASIN 
WITH ZONAL WLY FLOW ALOFT AROUND A BROAD UPPER LEVEL RIDGE. A 
WEAK PRESSURE GRADIENT ACROSS THE CARIBBEAN SEA IS MAINTAINING 
5-15 KT TRADE WINDS ACROSS MUCH OF THE BASIN.
  
THE ATLANTIC OCEAN...
A COLD FRONT IS MOVING ACROSS THE W ATLC...ENTERING THE 
DISCUSSION AREA NEAR 32N69W CONTINUING SW TO THE SOUTHERN 
FLORIDA PENINSULA ALONG 28N75W 26N80W AND INTO THE GULF OF 
MEXICO. NW WINDS 10-15 KT  BEHIND THE COLD FRONT ARE EXPECTED TO 
INCREASE TO GALE FORCE N OF 27N WITH SEAS TO 11 FT OVER THE NEXT 
18 HOURS. A SURFACE TROUGH IS ANALYZED 90 NM EAST OF THE COLD 
FRONT S OF 29N. THE COMBINATION OF THESE TWO BOUNDARIES ARE 
GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 
150 NM AHEAD OF THE COLD FRONT. THIS SYSTEM IS SUPPORTED BY A 
LONGWAVE UPPER TROUGH MOVING OFF THE EASTERN CONUS SEABOARD. 
BROAD UPPER LEVEL RIDGE COVERS THE REST OF THE BASIN E OF 65W 
ANCHORED BY A 1019 MB HIGH NEAR 27N46W PROVIDING GENERALLY FAIR 
WEATHER CONDITIONS ACROSS MUCH OF THE CENTRAL AND ERN ATLC. 
DESPITE THE WEATHER...A WEAK LOW PRESSURE SYSTEM DIPS INTO THE 
SURFACE RIDGE ALONG 32N30W WITH ISOLATED SHOWERS N OF 29N 
BETWEEN 27W-33W. ALSO...A WEAK UPPER LEVEL CYCLONE SPINS NEAR 
35N17W. THE TAIL END OF THE ASSOCIATED COLD FRONT EXTENDS EAST 
OF THE CANARY ISLANDS ALONG 32N10W TO 28N13W SUPPORTING ISOLATED 
SHOWERS AFFECTING THE COASTAL WATERS OF MOROCCO.

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

$$

GARCIA