000
AXNT20 KNHC 092355
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT MAR 09 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 
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 
01N22W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 
01N22W TO THE EQUATOR NEAR 27W THEN ALONG THE EQUATOR TO 39W. 
ISOLATED MODERATE CONVECTION IS S OF 04N BETWEEN 20W-40W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL RIDGE COVERS MOST OF THE GULF BASIN THIS 
EVENING THAT IS SUPPORTING A SURFACE RIDGE ANCHORED BY A 1027 MB 
HIGH CENTERED ACROSS SOUTH CAROLINA NEAR 34N82W. HOWEVER WATER 
VAPOR IMAGERY INDICATES A WEAK MID-LEVEL SHORTWAVE TROUGH IS 
LOCATED OVER SOUTHERN MISSISSIPPI NEAR 31N90W AND IS PROVIDING 
FOR ISOLATED SHOWERS N OF 27N BETWEEN 87W-95W. OTHERWISE THE 
REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF E-SE SOUTHERLY 
RETURN FLOW ON THE SOUTHWESTERN PERIPHERY OF THE SURFACE RIDGE 
MENTIONED ABOVE. BY EARLY SUNDAY...THE PRESSURE GRADIENT BETWEEN 
THE RIDGING AND DEVELOPING SURFACE LOW PRESSURE OVER THE 
SOUTHERN PLAINS WILL INCREASE SOUTHEASTERLY WINDS TO A RANGE OF 
20 TO 25 KT WITH THE ASSOCIATED COLD FRONT EMERGING OFF THE 
TEXAS AND LOUISIANA COAST BY LATE SUNDAY INTO EARLY MONDAY. 
WINDS WILL SHIFT NORTHERLY WEST OF THE FRONT AND SPREAD EASTWARD 
MONDAY INTO TUESDAY OF NEXT WEEK.

CARIBBEAN SEA...
MOST OF THE CARIBBEAN IS UNDER THE INFLUENCE OF FAIRLY DRY 
SOUTHWESTERLY FLOW ALOFT ON THE WESTERN PERIPHERY OF A 
ANTICYCLONIC CIRCULATION CENTERED OVER THE TROPICAL ATLC NEAR 
11N46W. WHILE THIS UPPER LEVEL FEATURE IS PROVIDING OVERALL 
STABLE CONDITIONS...AN EASTERN ATLC DEEP LAYERED LOW IS CENTERED 
NEAR 35N60W AND EXTENDS A COLD FRONT ACROSS THE CENTRAL ATLC 
THAT BECOMES STATIONARY AND ENTERS THE NE CARIBBEAN NEAR 18N61W 
EXTENDING SW TO 16N66W. ISOLATED SHOWERS CONTINUE TO OCCUR 
WITHIN 60 NM EITHER SIDE OF THE FRONT AND N OF 16N BETWEEN THE 
FRONT AND 74W OVER THE NORTH-CENTRAL CARIBBEAN...INCLUDING 
PUERTO RICO AND HISPANIOLA. OTHERWISE...E-NE TRADE ARE EXPECTED 
TO PERSIST THROUGH THE OVERNIGHT HOURS THROUGH LATE TUESDAY AS A 
SURFACE RIDGE SETTLES IN OVER THE SW NORTH ATLC. THE HIGHEST 
TRADES WILL ONCE AGAIN BE LOCATED OVER THE SOUTH-CENTRAL PORTION 
OF THE BASIN AND IN CLOSE PROXIMITY TO THE COAST OF COLOMBIA.

ATLANTIC OCEAN...
A CUT-OFF DEEP LAYERED LOW IS CENTERED OVER THE WESTERN NORTH 
ATLC NEAR 35N60W THAT REFLECTS TO THE SURFACE AS A STORM-FORCE 
991 MB LOW CENTERED NEAR 34N62W. WHILE THE STORM-FORCE 
CONDITIONS ARE FOUND NORTH OF THE DISCUSSION AREA...GALE FORCE 
CONDITIONS ARE OCCURRING N OF 29N WEST OF A SECONDARY FORMING 
COLD FRONT ANALYZED FROM 32N54W TO 27N57W TO 23N65W. ISOLATED 
SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THIS 
SECONDARY PUSH OF COLDER AIR. EAST OF THIS SECONDARY SURGE...THE 
MAIN COLD FRONT ASSOCIATED WITH THE OCCLUDED STORM-FORCE LOW IS 
ANALYZED INTO THE DISCUSSION AREA NEAR 32N43W TO 26N47W TO 
22N53W AND THEN BECOMES STATIONARY TO THE NE CARIBBEAN SEA NEAR 
17N63W. ISOLATED SHOWERS ARE OCCURRING WITHIN 150 NM EAST OF THE 
COLD FRONT...AND WITHIN 120 NM EITHER SIDE OF THE STATIONARY 
FRONT. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE 
OF A SURFACE RIDGE ANCHORED BY A 1022 MB HIGH CENTERED NEAR 
28N30W.

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

$$
HUFFMAN