000
AXNT20 KNHC 271747
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST THU JAN 27 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1715 UTC.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 5N9W 2N20W 3N30W 2N40W CROSSING 
THE EQUATOR AT 46W INTO NE BRAZIL. A CLUSTER OF MODERATE TO 
STRONG CONVECTION IS WITHIN AROUND 90 NM OF 4.5N11W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 210 NM N OF 
AXIS FROM 16W TO 33W. SIMILAR CONVECTION IS ALSO NOTED S OF 06N 
TO THE EQUATOR BETWEEN 42W AND 51W. 

...DISCUSSION...

GULF OF MEXICO...
A 1024 MB HIGH PRES CENTERED OVER SOUTH TEXAS NEAR 28N97W 
EXTENDS A RIDGE EWD ACROSS THE ENTIRE GULF COVERING ALSO THE 
FLORIDA PENINSULA AND SE MEXICO INCLUDING THE YUCATAN PENINSULA. 
THIS SYSTEM WILL MEANDER OVER THE CENTRAL GULF SAT...THEN SHIFT 
E OVER CENTRAL FLORIDA ON SUN ALLOWING SOUTHERLY RETURN FLOW TO 
DOMINATE MOST OF THE GULF WATERS SUN AND MON. THE COLD FRONT 
THAT WAS MOVING ACROSS THE SE PORTION OF THE GULF YESTERDAY HAS 
EXITED THE REGION AND NOW REMAINS STATIONARY OVER THE FAR NW 
CARIBBEAN. COLD AIR STRATOCUMULUS CLOUDS ARE SEEN COVERING THE 
EASTERN GULF WATERS BEHIND THE FRONT DUE TO THE ADVECTION OF 
COLD AIR OVER RELATIVELY WARM WATERS. PERSISTENT LOW CLOUDINESS 
WITH EMBEDDED LIGHT SHOWERS ARE NOTED OVER THE WESTERN GULF 
BANKING UP ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS... 
AND A COASTAL TROUGH IS ANALYZED ON THE 1500 UTC MAP ALONG 96W 
FROM 21N TO 27N. IN THE UPPER LEVELS...WLY FLOW DOMINATES THE 
REGION TRANSPORTING ABUNDANT MID/UPPER LEVEL MOISTURE FROM THE 
EPAC.  

CARIBBEAN SEA...
AS PREVIOUSLY MENTIONED...A STATIONARY FRONT LIES OVER THE FAR 
NW CARIBBEAN AND IS FORECAST TO DISSIPATE TONIGHT. A ROPE CLOUD 
DELINEATES THE FRONT ON VISIBLE SATELLITE PICTURES. THE 
REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF A RIDGE 
EXTENDING SE ACROSS THE CENTRAL ATLC FROM A 1027 MB HIGH 
SITUATED NEAR 35N46W. AS A RESULT...FRESH TRADE WINDS CONTINUE 
TO BLOW ACROSS THE EAST AND CENTRAL CARIBBEAN. PATCHES OF LOW 
LEVEL MOISTURE REMAIN EMBEDDED WITHIN THIS FLOW AS SEEN ON 
VISIBLE SATELLITE IMAGERY USHERING IN ISOLATED TO SCATTERED 
PASSING SHOWERS. THESE SHALLOW SHOWERS ARE MORE CONCENTRATED 
NEAR BUOY 42059 LOCATED IN THE EASTERN CARIBBEAN...AND SOUTH OF 
JAMAICA. SOME OF THIS PATCHES OF MOISTURE ARE ALSO MOVING ACROSS 
THE ABC ISLANDS. THE TRADE WINDS WILL RELAX SOME OVER THE 
CENTRAL AND EASTERN CARIBBEAN THROUGH THE END OF THE WEEK AS 
HIGH PRES SHIFTS ENE...THEN INCREASE AGAIN THIS WEEKEND INTO MON 
OVER THE CENTRAL CARIBBEAN WATERS AS HIGH PRES BUILDS AGAIN N OF 
AREA. COMPUTER MODELS SUGGEST WINDS OF 25-30 KT NEAR THE COAST 
OF COLOMBIA BY EARLY SUN. IN THE UPPER LEVELS...A BROAD RIDGE 
DOMINATES THE CARIBBEAN WITH MODERATE/STRONG SUBSIDENCE AND DRY 
STABLE AIR ALOFT COVERING THE AREA E OF 80W. 

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE FORECAST REGION NEAR 31N66W THEN EXTENDS 
SW TO WESTERN CUBA AND BECOMES STATIONARY OVER THE FAR NW 
CARIBBEAN. A BAND OF SHOWERS WITH ISOLATED TSTMS IS ASSOCIATED 
WITH THE FRONT WHICH IS FORECAST TO STALL ACROSS CUBA AND THE 
BAHAMAS THROUGH THIS EVENING WHILE THE NORTHEAST PORTIONS WILL 
CONTINUE TO MOVE SE. MOISTURE ASSOCIATED WITH THE TAIL END OF 
THE FRONT SHOULD REACH HISPANIOLA BY SAT. A SECOND COLD FRONT 
STRETCHES FROM A 1010 MB LOW PRES NEAR 31N34W TO 22N41W. AT THIS 
POINT...THE FRONT BECOMES TO DISSIPATE. SOME SHOWER ACTIVITY IS 
NOTED WITHIN 180 NM AHEAD OF THE FRONT MAINLY N OF 24N. IN 
BETWEEN FRONTS...THERE IS A RIDGE ANCHORED ON A 1028 MB HIGH 
LOCATED NEAR 35N46W. THE GRADIENT BETWEEN THE HIGH AND THE LOW 
PRESSURE MOVING SE INTO THE FORECAST AREA WILL PRODUCE A LARGE 
AREA OF NLY WINDS IN THE 25 TO 35 KT RANGE N OF 25N BETWEEN 35W 
AND 45W. A WEAK RIDGE COVERS THE EASTERN ATLC AND WEST AFRICA 
WITH A 1019 MB HIGH NEAR 22N20W THAT IS FORECAST TO DISSIPATE 
OVER THE NEXT 24 HOURS. ALOFT...A TROUGH/RIDGE/TROUGH PATTERN 
DOMINATES THE REGION. A STRONG SHORT WAVE TROUGH IS QUICKLY 
MOVING NE ALONG THE COAST OF NEW ENGLAND AND SUPPORTS THE 
WESTERNMOST COLD FRONT. THE BROAD UPPER RIDGE THAT COVERS THE 
CARIBBEAN SEA EXTENDS NWD OVER THE CENTRAL ATLC TO BEYOND 
31N58W. ANOTHER UPPER LEVEL TROUGH IS OVER THE E ATLC ALONG 38W 
N OF 20N. A JET STREAM BRANCH WITH CORE WINDS OF 70-90 KT ROUNDS 
THE BASE OF THIS TROUGH AND EXTENDS NE THEN E INTO NORTHERN 
AFRICA.  
 
FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
GR