000
AXNT20 KNHC 192344
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU APR 19 2012

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL 
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS INLAND ACROSS THE TROPICAL REGIONS OF 
WEST AFRICA INTO THE ATLC BASIN ACROSS THE COAST OF LIBERIA NEAR 
6N10W TO 1N20W...WHERE THE ITCZ AXIS CONTINUES ALONG 1S30W TO 
THE COAST OF BRAZIL NEAR 3S42W. SCATTERED MODERATE TO ISOLATED 
STRONG CONVECTION IS NOTED FROM THE EQUATOR TO 5N BETWEEN 5W AND 
20W. ISOLATED TO SCATTERED MODERATE CONVECTION IS S OF 4N 
BETWEEN 20W AND 34W.  

...DISCUSSION...

GULF OF MEXICO...
A WEAK 1016 HIGH PRES LOCATED NEAR 28N91W DOMINATES THE WESTERN 
HALF OF THE GULF PRODUCING MOSTLY FAIR WEATHER AND LIGHT WINDS. 
A SHORTWAVE TROUGH MOVING ACROSS THE SE CONUS AND THE NE PORTION 
OF THE GULF SUPPORTS A WEAK NEARLY STATIONARY LOW PRESSURE 
SYSTEM CENTERED OVER THE FLORIDA PANHANDLE NEAR PANAMA CITY AND 
ASSOCIATED COLD FRONT THAT EXTENDS SSW TO NEAR 26N84W. SOUTH 
THIS POINT...THE FRONT IS BECOMING ILL DEFINED. DOPPLER RADAR 
SHOWS SCATTERED SHOWERS AND TSTMS AHEAD OF THE LOW/FRONT OVER 
THE STATE OF FLORIDA. THIS FRONT IS FORECAST TO SLOWLY MOVE 
INLAND OVER CENTRAL FLORIDA TONIGHT BEFORE DISSIPATING ON FRI. 
THE WEATHER PATTERN WILL START TO CHANGE ACROSS THE REGION LATE 
FRI AS A DEEP LAYER UPPER TROUGH DEVELOPS OVER THE CENTRAL 
UNITED STATES AND ALL THE WAY SOUTH INTO THE GULF OF MEXICO. 
THIS FEATURE WILL SUPPORT THE DEVELOPMENT OF A SURFACE LOW PRES 
IN THE NORTHERN GULF OF MEXICO BY SATURDAY WITH A STRONG COLD 
FRONT EXTENDING SW ACROSS THE GULF WATERS. THE LOW PRES WILL 
MOVE EWD ACROSS THE NORTHERN GULF WATERS INTO NORTHERN FLORIDA 
THIS UPCOMING WEEKEND. THE FRONT WILL REACH FROM SE LOUISIANA TO 
TAMPICO MEXICO EARLY SAT...THEN SWEEP SE OF THE AREA SUN. FRESH 
TO STRONG WINDS AND BUILDING SEAS ARE EXPECTED IN THE WAKE OF 
THE FRONT. STRONG TO SEVERE STORMS ARE POSSIBLE OVER PARTS OF 
FLORIDA AHEAD OF THE FRONT THIS WEEKEND.

CARIBBEAN SEA...
HIGH PRES LOCATED N OF AREA WILL MAINTAIN MODERATE TO FRESH NE 
TO E WINDS ACROSS THE BASIN THROUGH FRI. THE MOST RECENT 
SCATTEROMETER DATA CONFIRMED THESE WIND SPEEDS. LATEST VIS 
SATELLITE IMAGERY SHOWS A SWIRL OF LOW CLOUDS OVER THE GULF OF 
HONDURAS AND A WEAK 1012 MB SURFACE LOW IS ANALYZED THERE. 
SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED OVER THE WESTERN 
CARIBBEAN AND THE YUCATAN PENINSULA DUE TO THE PRESENCE OF A 
WEAKENING STATIONARY FRONT. SIMILAR CONVECTION CAN BE FOUND OVER 
THE SW CARIBBEAN IN ASSOCIATION WITH THE COLOMBIAN/PANAMANIAN 
LOW SITUATED NEAR 10N77W. A TROUGH...REMNANT OF A COLD FRONT 
ENTERS THE CARIBBEAN SEA THROUGH MARTINIQUE IN THE WINDWARD 
ISLANDS. THIS TROUGH AND THE ASSOCIATED MOISTURE WILL CONTINUE 
TO DRIFT WWD ACROSS THE EASTERN CARIBBEAN ON FRI. EXPECT 
INCREASING WINDS ACROSS THE NW CARIBBEAN ON SAT AHEAD OF THE 
COLD FRONT FORECAST TO MOVE ACROSS THE GULF OF MEXICO. THE 
SOUTHERN PORTION OF THE COLD FRONT WILL MOVE ACROSS THE YUCATAN 
CHANNEL SAT EVENING REACHING FROM CENTRAL CUBA TO NEAR CABO 
GRACIAS A DIOS NICARAGUA SUN EVENING. FRESH W TO NW WINDS AREA 
EXPECTED BEHIND THE FRONT. ALOFT...A RIDGE CURRENTLY DOMINATES 
THE BASIN WITH SOME INCREASE IN MID/UPPER LEVEL MOISTURE OVER 
THE CENTRAL CARIBBEAN AHEAD OF A SHORTWAVE TROUGH LOCATED OVER 
THE FAR WEST PART OF THE BASIN.  

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE OVER THE WRN ATLC SUPPORTS A WEAK 1019 MB 
SURFACE HIGH NEAR 29N73W MAINTAINING MOSTLY FAIR WEATHER 
CONDITIONS AND LIGHT WINDS. SW AND W OF THIS RIDGE...SE TO S 
WINDS OF 10 TO 15 KT ARE BLOWING. THESE WINDS WILL FURTHER 
INCREASE TO 25 TO 30 KT LATE SAT AHEAD OF THE NEXT COLD FRONT 
FORECAST TO MOVE OFF THE SE U.S. COAST BY SUN. THE HIGH PRES 
WILL MOVE NE TOWARD THE BERMUDAS IN ABOUT 24 HOURS. SATELLITE 
IMAGERY ALONG WITH SCATTEROMETER DATA SHOW VERY WELL THE 
PRESENCE OF A 1006 MB LOW PRES LOCATED NEAR 29N55W. A SWIRL OF 
LOW CLOUDS IS ASSOCIATED WITH THE LOW PRES FORECAST TO MOVE N OF 
AREA DURING THE NEXT 24 HOURS. THE ATTENDANT COLD FRONT IS WELL 
DISPLACED TO THE EAST AND ENTERS THE FORECAST REGION NEAR 31N47W 
THEN CONTINUES SW TO 22N53W WHERE IT BEGINS TO DISSIPATE. 
SCATTERED SHOWERS AND TSTMS ARE NOTED WITHIN 150 NM AHEAD OF THE 
FRONT N OF 28N. FRESH TO STRONG SLY WINDS ARE ALSO SEEN AHEAD OF 
THE FRONT THANKS TO THE PRES GRADIENT BETWEEN THE LOW PRES AND A 
HIGH CENTERED NEAR THE AZORES. THIS HIGH EXTENDS A RIDGE OVER 
THE EASTERN ATLC. A SURFACE TROUGH IS OVER THE TROPICAL N ATLC 
WATERS JUST E OF THE LESSER ANTILLES ANALYZED FROM 17N57W TO 
11N62W. MOISTURE ASSOCIATED WITH THIS TROUGH WILL DRIFT WWD INTO 
THE CARIBBEAN SEA. A BAND OF TRANSVERSE HIGH CLOUDS EXTENDS FROM 
NORTHERN SOUTH AMERICA ACROSS THE WINDWARD ISLANDS INTO THE ATLC 
AROUND THE BASE OF AN UPPER LEVEL TROUGH EXTENDING BETWEEN 50W 
AND 60W...THEN ACROSS THE N PORTION OF A RIDGE ANCHORED ON A 
HIGH NEAR 7N36W.   

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

$$

GR