Atlantic Basin Tropical Discussion Atlantic | Pacific

000
AXNT20 KNHC 162354
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAY 16 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.

...TROPICAL WAVES...
A STRONG TROPICAL WAVE IS CURRENTLY OVER W AFRICA ALONG 15N9W TO 
7N9W CAUSING WIDESPREAD CONVECTION ACROSS W AFRICA. MODEL 
GUIDANCE INDICATES THE WAVE WILL MOVE OFF THE COAST AND OVER E 
ATLC WATERS WITHIN THE NEXT 24-36 HOURS. 

A TROPICAL WAVE IS ALONG 8N50W TO 4N52W MOVING W NEAR 15 KTS. 
WHILE THE WAVE WAS NOT EASILY IDENTIFIED OVER MUCH OF THE ATLC 
WATERS...UPPER AIR TIME SECTIONS FROM DAKAR SENEGAL INDICATE 
THAT THE WAVE MOVED OFF THE COAST AROUND 10/1200 UTC. THE 
CURRENT SPEED IS BASED OFF THIS ESTIMATION. TOTAL PRECIPITABLE 
WATER IMAGERY INDICATES THAT AN AREA OF MAXIMUM MOISTURE IS NEAR 
THE WAVE AXIS AS WELL AS TO THE W OF THE AXIS. CURRENTLY 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS MAINLY W OF THE 
AXIS FROM 2N-10N BETWEEN 50W-56W. MODERATE CONVECTION IS ALSO 
FARTHER W NEAR THE LESSER ANTILLES...BUT IS MORE ASSOCIATED WITH 
UPPER LEVEL DIFFLUENCE THAN THE WAVE. AS THE WAVE MOVES WWD 
THESE AREAS WILL LIKELY INTERACT AND COULD PRODUCE HEAVY 
RAINFALL OVER THE LESSER ANTILLES.


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

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF 
GUINEA AT 11N15W AND CONTINUES OVER THE E ATLC WATERS TO 6N25W. 
THE ITCZ CONTINUES FROM 6N25W ALONG 4N38W 6N49W. THERE IS NO 
DEEP CONVECTION BESIDES NEAR THE TROPICAL WAVES MENTIONED ABOVE.

...DISCUSSION...

THE GULF OF MEXICO...
SWLY FLOW ALOFT COVERS THE GULF OF MEXICO THIS EVENING BETWEEN 
AN UPPER LEVEL RIDGE OVER THE W ATLC AND AN UPPER LEVEL TROUGH 
MOVING ACROSS THE ERN CONUS AND PARALLELING THE NRN GULF COAST. 
THE UPPER TROUGH SUPPORTS A SURFACE TROUGH THAT EXTENDS FROM THE 
FLORIDA PANHANDLE AT 31N85W TO THE YUCATAN PENINSULA ALONG 
29N86W 25N87W 18N89W...AS OF 2100 UTC. SURFACE CONVERGENCE NEAR 
THE TROUGH ALONG WITH MOIST DIFFLUENT FLOW ALOFT IS HELPING 
PRODUCE WIDESPREAD SHOWERS AND THUNDERSTORMS E OF THE TROUGH 
AXIS WITH THE STRONGEST ACTIVITY MOVING OVER CENTRAL FLORIDA. 
SCATTERED SHOWERS/THUNDERSTORMS HAVE ALSO FORMED ALONG THE COAST 
OF LOUISIANA LIKELY DUE TO DIFFLUENCE ALOFT AROUND THE UPPER 
TROUGH AXIS. THE REMAINDER OF THE WRN GULF IS UNDER MOSTLY FAIR 
CONDITIONS WITH LIGHT WINDS AND MOSTLY CLEAR SKIES. WINDS ARE 
STRONGER IN THE ERN GULF NEAR THE TROUGH AS WELL AS IN 
THUNDERSTORMS. EXPECT MOIST CONDITIONS TO REMAIN OVER THE ERN 
GULF FOR AT LEAST THE NEXT 24 HOURS. 

THE CARIBBEAN SEA...
SHOWERS/THUNDERSTORMS COVER MUCH OF THE YUCATAN PENINSULA AND 
NRN CENTRAL AMERICA ASSOCIATED WITH A SURFACE TROUGH IN THE ERN 
GULF OF MEXICO WHICH EXTENDS INTO THE YUCATAN PENINSULA. 
OVERCAST SKIES COVER THE REMAINDER OF THE NW CARIBBEAN. 
ALOFT...AN UPPER LEVEL RIDGE EXTENDS FROM COSTA RICA ACROSS ERN 
CUBA AND INTO THE W ATLC WHILE AN UPPER LEVEL TROUGH EXTENDS 
DOWN THE LESSER ANTILLES. DRY AIR ALOFT COVERS THE AREA BETWEEN 
THESE TWO UPPER LEVEL FEATURES...WHICH IS HELPING MAINTAIN FAIR 
CONDITIONS ACROSS THE CENTRAL AND ERN CARIBBEAN. A FEW 
SHOWERS/THUNDERSTORMS ARE NOW APPROACHING THE LESSER ANTILLES 
FROM THE E ATLC ASSOCIATED WITH DIFFLUENCE ALOFT AROUND THE E 
SIDE OF THE UPPER TROUGH. ELY TRADEWIND FLOW COVERS MUCH OF THE 
AREA REACHING 15-20 KTS. 

THE ATLANTIC OCEAN...
MOIST CONDITIONS WITH SCATTERED SHOWERS AND ISOLATED 
THUNDERSTORMS COVER THE FAR W ATLC W OF 72W. THIS IS ASSOCIATED 
WITH MOIST SWLY AND DIFFLUENT FLOW ALOFT BETWEEN AN UPPER LEVEL 
TROUGH OVER THE ERN CONUS AND AN UPPER LEVEL RIDGE EXTENDING 
FROM THE CARIBBEAN ACROSS THE BAHAMAS TO 40N57W. THE UPPER RIDGE 
SUPPORTS A BROAD SURFACE RIDGE ANCHORED BY A 1032 MB HIGH AT 
38N53W. THE RIDGE IS PROVIDING FAIR CONDITIONS ACROSS MUCH OF 
THE CENTRAL AND ERN ATLC EXCEPT FOR THE AREA E OF THE LESSER 
ANTILLES. AN UPPER LEVEL TROUGH EXTENDS FROM W OF THE AZORES 
ISLANDS TO THE NE CARIBBEAN AND DOWN THE LESSER ANTILLES...WHICH 
IS PROVIDING DIFFLUENCE ALOFT OVER THE AREA E OF THE ISLANDS. 
THIS IS RESULTING IN WIDESPREAD SHOWERS/POSSIBLE THUNDERSTORMS S 
OF 17N BETWEEN 52W-61W. A TROPICAL WAVE IS LOCATED TO THE SE OF 
THIS AREA AND THE WAVE MAY INTERACT WITH THE UPPER TROUGH AS IT 
MOVES WWD. OVER THE TROPICAL ATLC...AN UPPER LEVEL RIDGE EXTENDS 
FROM NEAR 7N32W ACROSS THE CAPE VERDE ISLANDS TO NW AFRICA. THE 
LAST VISIBLE SATELLITE IMAGES OF THE DAY ALONG WITH GOES-R 
ENHANCEMENTS INDICATE THAT A LARGE AREA OF DUST HAS EMERGED OFF 
THE COAST OF AFRICA EXTENDING TO 36W.

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

$$
WALTON