000
AXNT20 KNHC 181702
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAR 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 1645 UTC.

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

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF 
LIBERIA NEAR 5N9W TO 2N18W...WHERE THE ITCZ CONTINUES ALONG 
1N30W 1N40W TO THE COAST OF BRAZIL AT 1S47W. SCATTERED MODERATE 
TO STRONG CONVECTION IS FROM 3S-5N BETWEEN THE PRIME MERIDIAN 
AND 16W.

...DISCUSSION...

THE GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES UPPER LEVEL RIDGING COVERING THE 
GULF OF MEXICO THIS AFTERNOON. MOISTURE ALOFT IS STREAMING 
ACROSS THE WRN GULF AROUND THE W SIDE OF THE UPPER RIDGE 
PROVIDING SOME UPPER LEVEL CLOUD COVER TO THIS REGION. THE UPPER 
RIDGE ALSO SUPPORTS SURFACE RIDGING EXTENDING FROM THE NE CORNER 
TO SW CORNER OF THE GULF. MOSTLY FAIR CONDITIONS AND MODERATE 
10-15 KT ANTI-CYCLONIC FLOW IS PRESENT ACROSS THE BASIN. SHORT 
RANGE COMPUTER MODELS SUGGEST INCREASING RETURN FLOW OVER THE 
WRN BASIN UP TO 25 KT WITHIN THE NEXT 24 HOURS. OTHERWISE... 
LITTLE CHANGE IS EXPECTED DURING THE FORECAST PERIOD. 

THE CARIBBEAN SEA...
MOSTLY FAIR CONDITIONS CONTINUE ACROSS THE CARIBBEAN SEA THIS 
AFTERNOON...DUE TO DRY AIR ALOFT AROUND A BROAD UPPER LEVEL 
TROUGH OVER THE WRN HALF OF THE BASIN ON WATER VAPOR IMAGERY. 
MOISTURE ALOFT IS STREAMING OVER THE SW...S-CENTRAL...AND ERN 
CARIBBEAN AROUND THE E SIDE OF THE UPPER TROUGH SUPPORTING 
CIRRUS CLOUDS OVER THESE AREAS. THE REMAINDER OF THE BASIN 
RELATIVELY HAS CLEAR SKIES WITH A FEW ISOLATED SHOWERS EMBEDDED 
IN THE TRADEWIND FLOW OF 10-15 KTS. SOME STRONGER WINDS ARE 
OBSERVED NEAR THE COASTAL WATERS OF COLOMBIA. NO SIGNIFICANT 
CHANGES ARE EXPECTED OVER THE NEXT COUPLE OF DAYS. 

THE ATLANTIC OCEAN...
A DRY UPPER LEVEL TROUGH COVERS MOST OF THE WRN ATLC WITH A 
BROAD UPPER CYCLONIC CIRCULATION CENTERED NEAR 25N66W. THIS 
FEATURE IS GENERATING ENOUGH LIFTING AND INSTABILITY TO GIVE AN 
AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 
21N-27N BETWEEN 60W-70W. AS THE UPPER LEVEL FEATURE CONTINUES TO 
REACH THE SURFACE...A TROUGH COULD BE ANALYZED DURING THE NEXT 6 
HOURS IN THIS AREA. TO THE ENE OF THIS AREA OF CONVECTION...A 
SURFACE TROUGH IS ANALYZED FROM 30N50W TO 25N58W PRODUCING 
SIMILAR CONVECTION WITHIN 70 NM ON EITHER SIDE OF THE AXIS. AN 
UPPER LEVEL RIDGE COVERS THE REMAINDER OF THE CENTRAL AND ERN 
ATLC SUPPORTING SURFACE RIDGING ANCHORED BY A 1035 MB HIGH NE OF 
THE AZORES NEAR 42N18W...PROVIDING MOSTLY FAIR CONDITIONS ACROSS 
THE REMAINDER OF THE BASIN. WITHIN THIS REGION OF FAIR WEATHER 
...GOES-R SATELLITE ENHANCED IMAGERY ALONG WITH VISIBLE 
SATELLITE IMAGERY INDICATE AN AREA OF SAHARAN DUST MOVING OFF 
WEST AFRICA EXTENDING TO 40W.

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

$$

GARCIA