000
AXNT20 KNHC 171050
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT MAR 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 1115 UTC.

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

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE NRN COAST OF 
GUINEA NEAR 11N15W TO 3N21W. THE ITCZ CONTINUES FROM 3N21 ALONG 
2N30W CROSSING THE EQUATOR AT 40W TO 3S48W.  

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL RIDGE IS MOVING ACROSS THE GULF OF MEXICO THIS 
MORNING WITH AXIS EXTENDING FROM THE BAY OF CAMPECHE TO 
MISSISSIPPI. UPPER TROUGHING COVERS THE FAR ERN GULF WITH AXIS E 
OF THE FLORIDA PENINSULA INTO THE WRN CARIBBEAN. AT THE 
SURFACE...MAINLY SURFACE RIDGING COVERS THE BASIN EXTENDING FROM 
HIGH PRESSURE OVER SOUTH CAROLINA AND THE W ATLC. A WEAK SURFACE 
TROUGH EXTENDS ACROSS THE YUCATAN PENINSULA ALONG 22N88W TO 
17N93W. NO SIGNIFICANT WEATHER IS ASSOCIATED WITH THE TROUGH. 
MOSTLY CLEAR SKIES COVER THE MAJORITY OF THE BASIN BESIDES SOME 
UPPER LEVEL CLOUD COVER OVER THE WRN GULF WHERE UPPER LEVEL 
MOISTURE IS STREAMING TO THE NE AROUND THE W SIDE OF THE UPPER 
RIDGE. 10-15 KT E-SE SURFACE WINDS ARE AROUND THE SURFACE RIDGE. 
EXPECT THE SURFACE TROUGH OVER THE YUCATAN TO DRIFT WWD AS 
SURFACE RIDGING REMAINS ACROSS THE BASIN FOR THE NEXT SEVERAL 
DAYS. 

THE CARIBBEAN SEA...
MOSTLY FAIR CONDITIONS REMAIN ACROSS THE CARIBBEAN DUE TO DRY 
AIR ALOFT AROUND AN UPPER LEVEL TROUGH IN THE WRN CARIBBEAN 
EXTENDING FROM CENTRAL CUBA TO COSTA RICA. SOME UPPER LEVEL 
MOISTURE IS STREAMING OVER THE ERN CARIBBEAN AROUND THE E SIDE 
OF THE UPPER TROUGH SUPPORTING SOME UPPER LEVEL CLOUDS. POSSIBLE 
ISOLATED SHOWERS MAY ALSO BE BELOW THE UPPER CLOUDS IN THE SE 
CARIBBEAN N OF VENEZUELA. THE REMAINDER OF THE BASIN HAS CLEAR 
SKIES BESIDES A FEW ISOLATED SHOWERS OVER S OF HAITI AND JAMAICA 
AND E OF NICARAGUA. TRADEWIND FLOW OF 15-20 KTS IS ACROSS MUCH 
OF THE AREA WITH SOME STRONGER WINDS AROUND THE COAST OF 
COLOMBIA. EXPECT LITTLE CHANGE OVER THE NEXT COUPLE OF DAYS. 

THE ATLANTIC OCEAN...
AMPLE DRY AIR AND SUBSIDENCE ALOFT ARE KEEPING THE FAR WRN ATLC 
UNDER MOSTLY CLEAR SKIES AND FAIR CONDITIONS. AN UPPER LEVEL 
RIDGE EXTENDS FROM THE NW BAHAMAS TO 33N75W CONTINUING TOWARDS 
THE NE. THE UPPER RIDGE SUPPORTS A 1025 MB SURFACE HIGH NEAR 
33N67W. SHORTWAVE UPPER TROUGHS ARE TO EITHER SIDE OF THE RIDGE 
ALL EMBEDDED WITHIN A LONGWAVE UPPER TROUGH OVER THE WRN 
CARIBBEAN AND THE BAHAMAS. THIS PATTERN IS SUPPORTING A PAIR OF 
SURFACE TROUGHS. THE FIRST EXTENDS N OF THE BAHAMAS FROM 28N73W 
TO 23N70W. ISOLATED SHOWERS ARE E OF THE AXIS FROM 23N-28N 
BETWEEN 65W-73W. THE SECOND TROUGH IS FARTHER E ALONG 28N55W TO 
24N59W. SCATTERED SHOWERS ARE W OF THE AXIS FROM 20N-30N BETWEEN 
57W-65W...AND E OF THE AXIS FROM 23N-30N BETWEEN 51W-55W. ACROSS 
THE CENTRAL ATLC...A BROAD UPPER RIDGE IS S OF 33N WITH AN UPPER 
LEVEL TROUGH N OF 33N WITH AXIS ALONG 47W. AN UPPER RIDGE IS E 
OF THE UPPER TROUGH ALONG 34W SUPPORTING A 1026 MB HIGH NEAR 
33N43W...AND A 1033 MB HIGH NEAR 42N31W WHICH ARE PROVIDING FAIR 
WEATHER ACROSS THE REMAINDER OF THE AREA. AN UPPER LEVEL TROUGH 
COVERS THE FAR ERN ATLC WITH AXIS EXTENDING ACROSS THE MADEIRA 
AND CANARY ISLANDS TO THE CAPE VERDE ISLANDS. THE UPPER TROUGH 
IS SUPPORTING A FRONTAL BOUNDARY N OF THE AREA.

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

$$
WALTON