000
AXNT20 KNHC 292309
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAR 29 2013

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 
2245 UTC.

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

THE MONSOON TROUGH PASSES THROUGH THE COAST OF GUINEA-BISSAU AT 
12N16W INTO THE EASTERN TROPICAL ATLC ALONG 6N18W 4N21W. THE 
ITCZ BEGINS AT 4N21W AND CONTINUES ALONG 2N34W EQ41W 2S47W. 
ISOLATED MODERATE/STRONG CONVECTION IS FROM 3N-5N BETWEEN 19W-
20W.

...DISCUSSION...

THE GULF OF MEXICO... 

SURFACE RIDGING CONTINUES TO DOMINATE THE GULF OF MEXICO 
ANCHORED BY A 1029 MB HIGH OVER THE BIG BEND OF FLORIDA NEAR 
30N84W. THIS PATTERN IS PROVIDING LIGHT WINDS IN THE NE GULF 
WITH 10-15 KT ANTI-CYCLONIC FLOW ACROSS THE REMAINDER OF THE 
AREA. SKIES ARE MOSTLY CLEAR EXCEPT FOR A FEW PATCHES OF LOW 
CLOUDS ACROSS THE WESTERN GULF. ALOFT...MAINLY ZONAL WESTERLY 
FLOW IS PRESENT ALTHOUGH AN UPPER LEVEL RIDGE IS EXTENDS THROUGH 
THE MIDWEST AND OVER EASTERN TEXAS AND THE FAR NW GULF 
SUPPORTING THE SURFACE RIDGE. DRY AIR ALOFT IS ALSO HELPING 
MAINTAIN THE FAIR WEATHER ACROSS THE BASIN. THE SURFACE RIDGE 
WILL CONTINUE TO MOVE EAST OVER THE NEXT COUPLE OF DAYS.

THE CARIBBEAN SEA...

A WEAK SHEAR AXIS CONTINUES TO EXTEND FROM THE CENTRAL ATLC 
ACROSS PUERTO RICO...HISPANIOLA...AND INTO THE WESTERN CARIBBEAN 
ALONG 18N64W 17N78W 14N82W. BASED ON RECENT ASCAT PASSES...THE 
AXIS IS NEARLY DISSIPATED WITH WINDS OF EQUAL SPEEDS TO EITHER 
SIDE. HOWEVER...SHOWERS ARE STILL BEING PRODUCED IN THE AREA 
WITH ISOLATED ACTIVITY UP TO 200 NM NORTH AND WEST OF THE AXIS. 
THE REMAINDER OF THE BASIN IS UNDER MOSTLY CLEAR SKIES DUE TO 
DRY AIR ALOFT IN MAINLY WEST-SOUTHWEST FLOW. AT THE 
SURFACE...TRADEWINDS OF 15-20 KT SPREAD THROUGHOUT WITH A FEW 
AREAS OF 25 KT WINDS SOUTH OF HISPANIOLA. THE SHEAR AXIS WILL 
CONTINUE TO DISSIPATE WHILE THE AREA OF 25 KT TRADEWINDS SPREADS 
ACROSS MUCH OF THE CENTRAL CARIBBEAN. 

THE ATLANTIC OCEAN... 

SURFACE RIDGING ACROSS THE GULF OF MEXICO CONTINUES TO SPREAD 
OVER INTO THE WEST ATLC AND WILL CONTINUE TO DO SO OVER THE NEXT 
FEW DAYS. THE RIDGE IS PROVIDING FAIR CONDITIONS ACROSS THE WEST 
ATLC. A COLD FRONT STILL IMPACTS PORTIONS OF THE EASTERN AND 
CENTRAL ATLC ENTERING THE DISCUSSION AREA NEAR 32N35W AND 
TRAILING SW TOWARDS THE CARIBBEAN ALONG 23N50W 19N62W CONTINUING 
AS A SHEAR AXIS ACROSS PUERTO RICO AND HISPANIOLA. ISOLATED 
SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE AXIS. A BROAD UPPER 
RIDGE COVERING MUCH OF THE CENTRAL AND EASTERN ATLC SUPPORTS A 
SURFACE RIDGE COVERING THE REMAINDER OF THE BASIN ANCHORED BY A 
1021 MB HIGH NEAR 28N22W. THE RIDGE IS PROVIDING FAIR WEATHER 
ACROSS THIS AREA. 

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

$$
WALTON