000
AXNT20 KNHC 181803
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED APR 18 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL SIERRA LEONE NEAR 8N13W
TO 3N20W 2N24W. THE ITCZ CONTINUES FROM 2N24W...CROSSING THE 
EQUATOR ALONG 27W...TO 1S33W. ISOLATED MODERATE TO LOCALLY 
STRONG CONVECTIVE PRECIPITATION IS TO THE SOUTH OF 7N12W 5N24W
5N33W 6N41W 9N52W 9N57W. 

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL TROUGH THAT IS MOVING THROUGH THE CENTRAL GULF OF 
MEXICO SUPPORTS A COLD FRONT/STATIONARY FRONT. THE FRONT IS COLD 
FROM A 1013 MB WESTERN FLORIDA PANHANDLE LOW PRESSURE CENTER...
TO THE CENTRAL GULF WATERS. THE FRONT BECOMES STATIONARY FROM
25N90W TO 18N93W IN THE ISTHMUS OF TEHUANTEPEC OF MEXICO.
ISOLATED MODERATE CONVECTIVE PRECIPITATION COVERS THE GULF OF 
MEXICO FROM THE YUCATAN PENINSULA TO THE FLORIDA GULF COAST 
BETWEEN 83W AND 89W. BROKEN LOW LEVEL CLOUDS ARE TO THE NORTH
OF 25N BETWEEN 88W AND 93W. NO 20 KNOT WINDS ARE OBSERVED
AND/OR FORECAST IN THE GULF OF MEXICO FOR THE NEXT 48 HOURS.
THE WIND SPEEDS ARE FORECAST TO INCREASE TO 20 TO 30 KNOTS
BY SATURDAY IN MANY AREAS. PLEASE CONTINUE TO REFER TO THE
HIGH SEAS FORECAST...MIAHSFAT2...AND THE OFFSHORE FORECAST...
MIAOFFNT4...FOR SPECIFIC DETAILS AND ANY CHANGING CONDITIONS
DURING THE NEXT 48 HOURS OR SO.

THE CARIBBEAN SEA...
AN UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC OCEAN NEAR
25N65W...ACROSS THE GREATER ANTILLES...INTO THE CENTRAL 
CARIBBEAN SEA NEAR 15N71W. RAINSHOWERS ARE POSSIBLE IN THE 
NORTHWESTERN CORNER OF THE AREA TO THE NORTH OF 17N TO THE
WEST OF 82W...POSSIBLY RELATED TO THE FRONTAL BOUNDARY THAT 
REACHES THE ISTHMUS OF TEHUANTEPEC OF MEXICO. SCATTERED MODERATE 
TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS IN THE 
SOUTHWESTERN CORNER OF THE AREA. IT IS POSSIBLE THAT THIS 
PRECIPITATION MAY BE RELATED TO THE EASTWARD EXTENSION OF
A SURFACE TROUGH THAT EXTENDS FROM COSTA RICA INTO THE EASTERN
PACIFIC OCEAN NEAR 6N90W. THE WHOLE AREA OF THE SOUTHWESTERN 
CORNER OF THE CARIBBEAN SEA IS IN BROAD SURFACE LOW PRESSURE.
PLEASE REFER TO THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE 
OFFSHORE FORECAST...MIAOFFNT3...FOR SPECIFIC DETAILS ABOUT
THE 20 KNOT WINDS...AND THE SEA HEIGHTS RANGING FROM
8 TO 10 FEET...MOSTLY IN THE AREAS THAT ARE TO THE WEST
OF 63W...DURING THE NEXT 24 TO 48 HOURS.

THE ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH EXTENDS FROM A 32N57W CYCLONIC CIRCULATION 
CENTER...SOUTHWESTWARD IN THE DIRECTION OF THE GREATER ANTILLES 
AND THE SOUTHEASTERN BAHAMAS. THE TROUGH CONTINUES INTO THE 
CENTRAL CARIBBEAN SEA NEAR 15N71W. THE TROUGH SUPPORTS
A 1005 MB LOW PRESSURE CENTER AND FRONTAL BOUNDARY. THE LOW 
CENTER IS NEAR 33N59W...AND FORECAST TO MOVE NEAR 29N56W AT
1008 MB. A COLD FRONT PASSES THROUGH 32N53W TO 26N56W AND 
24N64W. A DISSIPATING STATIONARY FRONT PASSES THROUGH 32N46W
TO 26N47W 20N54W AND 16N60W. HIGH LEVEL MOISTURE IS WITHIN
800 NM TO THE SOUTHEAST OF THE LINE THAT GOES FROM 16N60W TO
21N53W TO 26N48W. THE MOISTURE IS MOVING NORTHEASTWARD ALONG THE 
SOUTHEASTERN SIDE OF THE CYCLONIC FLOW THAT IS RELATED TO THE 
32N57W UPPER LEVEL CYCLONIC CENTER. ISOLATED TO WIDELY SCATTERED 
MODERATE CONVECTIVE PRECIPITATION IS FROM 10N TO 17N BETWEEN
50W AND 61W. SCATTERED MODERATE TO ISOLATED STRONG PRECIPITATION
IS TO THE NORTH OF 22N BETWEEN 43W AND 50W...AND TO THE NORTH
OF 27N BETWEEN 50W AND 60W. PLEASE REFER TO THE HIGH SEAS 
FORECAST...MIAHSFAT2...FOR SPECIFIC DETAILS ABOUT THE 20 TO
25 KNOT WINDS...AND SEA HEIGHTS REACHING 11 FEET... RELATED TO
THE FRONTAL BOUNDARY AND THE 1005 MB LOW PRESSURE CENTER THAT
IS NEAR 33N59W. BROAD SURFACE ANTICYCLONIC WIND COVERS THE 
ATLANTIC OCEAN THAT IS TO THE WEST OF THE 32N53W 24N64W COLD
FRONT. THE ANTICYCLONIC WIND FLOW MOVES AROUND A 1022 MB HIGH 
PRESSURE CENTER THAT IS NEAR 29N75W. AN UPPER LEVEL CYCLONIC 
CIRCULATION CENTER IS MOVING FROM THE WESTERN SAHARA INTO 
MAURITANIA. BROAD UPPER LEVEL CYCLONIC WIND FLOW COVERS THE 
ATLANTIC OCEAN TO THE NORTH OF 14N BETWEEN AFRICA AND 30W.
A SURFACE RIDGE EXTENDS IS ALONG 32W FROM 10N BEYOND 32N...
TO A 1034 MB HIGH PRESSURE CENTER THAT IS NEAR 39N33W.

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

$$
MT