000
AXNT20 KNHC 122353
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 12 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 
2345 UTC.

...SPECIAL FEATURE...

A GALE 1009 MB LOW IS OVER THE E ATLC CENTERED NEAR 33N30W. A 
BROAD UPPER LEVEL LOW SITS NEAR THE SAME LOCATION OF THE SURFACE 
LOW SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS 
WITHIN 140 NM N OF THE LOW CENTER. THERE IS SOME POTENTIAL FOR 
ADDITIONAL DEVELOPMENT AS THE SYSTEM MOVES LITTLE DURING THE 
NEXT COUPLE OF DAYS...AND THE LOW HAS A MEDIUM CHANCE OF 
BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT 48 
HOURS. ADDITIONAL SPECIAL TROPICAL WEATHER OUTLOOKS WILL BE 
ISSUED ON THIS SYSTEM LATER TODAY OR SUNDAY IF NECESSARY.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL 
ATLC ALONG THE NRN COAST OF SIERRA LEONE NEAR 08N13W TO 5N18W 
WHERE THE ITCZ CONTINUES ALONG 6N32W TO THE COAST OF BRAZIL NEAR 
2N51W. CLUSTERS OF SCATTERED WEAK TO ISOLATED MODERATE 
CONVECTION WITHIN 130 NM ON EITHER SIDE OF THE ITCZ W OF 30W.  

...DISCUSSION...

GULF OF MEXICO...
A LOW PRESSURE SYSTEM MOVES ACROSS THE SE CONUS SUPPORTING A 
COLD FRONT EXTENDING SW ACROSS THE NW GULF...ENTERING THE 
DISCUSSION AREA THROUGH THE LOUISIANA COAST ALONG 29N91W TO THE 
COAST OF MEXICO NEAR 24N98W. DESPITE THE POSITION OF THE FRONT 
...THE CONVECTION ASSOCIATED TO IT LIES AHEAD N OF 26N W OF 87W. 
A PREFRONTAL SQUALL LINE IS EMBEDDED IN THIS CONVECTIVE AREA 
ANALYZED FORM 30N88W TO 26N92W. MODERATE TO HEAVY SHOWERS WITH 
NUMEROUS CLOUD TO SURFACE LIGHTNING AND GUSTY WINDS UP TO 30 KT 
ARE REPORTED WITHIN 40 NM ON EITHER SIDE OF THE SQUALL LINE. THE 
ACTIVITY IS SUPPORTED ALOFT BY STRONG DIFFLUENCE FLOW NOTED ON 
WATER VAPOR IMAGERY. AS THE FRONT CONTINUES TO TRACK ENE...THE 
ACTIVITY ACROSS THE N-CENTRAL AND NE GULF WILL SLOWLY DECREASE 
DURING THE NEXT 24 HOURS. OTHERWISE...A BROAD UPPER LEVEL 
ANTICYCLONIC CIRCULATION CENTERED OVER CENTRAL AMERICA NEAR EL 
SALVADOR EXTENDS A RIDGE AXIS N-EASTWARD ACROSS THE GULF. THE 
UPPER FLOW AROUND THE UPPER HIGH IS DRAWING CIRRUS ACROSS MUCH 
OF THE BASIN EXCEPT THE SE CORNER.      

CARIBBEAN SEA...
A BROAD UPPER ANTICYCLONIC CIRCULATION IS CENTERED OVER EL 
SALVADOR. THIS FEATURE IS INFLUENCING MOST OF THE CARIBBEAN SEA 
WITH DRY AIR AND MODERATE TO STRONG SUBSIDENCE ALOFT ACROSS THE 
DISCUSSION AREA. FRESH TO STRONG TRADE WINDS ARE OBSERVED WITH 
SOME LOW TOP SCATTERED SHOWERS EMBEDDED IN THE FLOW. SOME OF 
THE STRONGEST WINDS ARE OBSERVED ALONG THE COASTAL WATERS OF 
COLOMBIA. THIS FLOW IS BANKING SIMILAR CONVECTION WITHIN 90 NM 
ALONG THE COAST OF PANAMA AND COSTA RICA. OTHERWISE...FAIR 
WEATHER IS ACROSS THE REMAINDER OF THE CARIBBEAN THIS EVENING. 

ATLANTIC OCEAN...
AN UPPER TROUGH MOVES ACROSS THE NW ATLC N OF THE AREA 
SUPPORTING A COLD FRONT THAT ENTERS OUR REGION ALONG 32N60W TO 
27N63W WHERE IT BECOMES A SURFACE TROUGH TO NEAR 22N65W. THIS 
FRONTAL BOUNDARY IS GENERATING SCATTERED SHOWERS AND 
THUNDERSTORMS N OF 20N BETWEEN 57W AND THE FRONT AXIS. SIMILAR 
CONVECTION IS OVER THE NRN COASTAL WATERS AND INLAND PORTIONS OF 
HISPANIOLA...EXTENDING UP TO 90 NM OFFSHORE. A SURFACE TROUGH 
IS ANALYZED WITHIN THIS CONVECTIVE AREA FROM 22N68W TO 18N71W. A 
SURFACE RIDGE IS BUILDING W OF THE FRONT ANCHORED BY A 1028 MB 
NEAR 34N73W. SURFACE RIDGING COVERS THE REMAINDER OF THE CENTRAL 
AND ERN ATLC. THE W ATLC COLD FRONT WILL CONTINUE TO TRACK 
EASTWARD WITH CONVECTION OVER THE NEXT 24 HOURS.   

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

$$

GARCIA