000
AXNT20 KNHC 221745
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI MAR 22 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1715 UTC.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL SIERRA LEONE NEAR 
8N13W TO 4N18W 1N22W EQ28W. THE ITCZ CONTINUES FROM EQ28W AND 
THEN ALONG EQ35W EQ44W TO EQ49W. WIDESPREAD MODERATE TO ISOLATED 
STRONG CONVECTION IS OCURRING FROM 2S TO 5N BETWEEN 17W AND 28W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 2S TO 
6N WEST OF 42W.

...DISCUSSION...

THE GULF OF MEXICO... 
IN THE MIDDLE TO UPPER LEVELS WESTERLY-SOUTHWESTERLY FLOW IS 
ADVECTING SOME MOISTURE FROM THE E PACIFIC WHICH IS SUPPORTING 
ISOLATED SHOWERS OVER THE WESTERN...NORTHERN AND EASTERN GULF. 
SHOWERS IN THE EASTERN GULF ARE ALSO BEING ENHANCED BY A SURFACE 
TROUGH THAT EXTENDS FROM 26N84W TO THE EVERGLADES NEAR 25N81W 
AND THEN ACROSS SOUTHERN FLORIDA TO THE WEST ATLC. SOUTHEASTERLY 
WINDS OF 10-15 KT DOMINATE THE EASTERN GULF E OF 89W WHILE 
SOUTHERLY FLOW OF THE SAME MAGNITUDE SPREAD W OF THAT MERIDIAN. 
HOWEVER WINDS UP TO 20 KT CAN BE FOUND ALONG THE NORTHERN GULF 
COAST E OF 90W. SOUTHERLY FLOW WILL BUILD OVER THE ENTIRE BASIN 
WITHIN 24 HOURS WITH WINDS INCREASING UP TO 25 KT OVER THE 
CENTRAL GULF S OF 25N. SCATTERED/ISOLATED SHOWERS ARE POSSIBLE 
DURING THIS PERIOD AS MOSITURE FROM THE CARIBBEAN WATERS IS 
ADVECTED OVER THE E GULF AND THE FLORIDA PENINSULA.

THE CARIBBEAN SEA... 
IN THE MIDDLE TO UPPER LEVELS WESTERLY FLOW SPREAD WEST OF 75W 
WHILE SOUTHWESTERLY FLOW DOMINATE THE REST OF THE BASIN 
SURROUNDING THE PERIPHERY OF AN UPPER LEVEL RIDGE WITH AXIS NEAR 
50W. WATER VAPOR IMAGERY INDICATE DRY AIR ALOF ACROSS MOST OF 
THE BASIN WHICH IS SUPPORTING FAIR WEATHER OVER THE CARIBBEAN 
WATERS. RAINSHOWERS ACTIVITY IS WITHIN 70 NM ALONG THE COAST OF 
COLOMBIA AS WELL AS 140 NM S OF DOMINICAN REPUBLIC BETWEEN 68W 
AND 71W. IN TERMS OF WINDS...EASTERLY TRADEWINDS IN THE RANGE OF 
10-15 KT SPREAD OVER THE SOUTHERN...CENTRAL AND EASTERN 
CARIBBEAN WHILE SOUTHEASTERLY FLOW UP TO 20 KT DOMINATE W OF 80W 
AND N OF 16N. OVER THE COURSE OF 24 HOURS...CHANGE IN WIND 
DIRECTION IS NOT EXPECTED...HOWEVER A SLIGHT INCREASE IN WIND 
MAGNITUDE OVER THE WESTERN CARIBBEAN IS POSSIBLE DUE TO AN 
INCREASE IN PRESSURE GRADIENT IN THE YUCATAN PENINSULA. 
 
THE ATLANTIC OCEAN...
AS OF 1500 UTC...A HIGH PRESSURE HAS REDEFINED OVER THE WEST 
ATLC NEAR 27N76W WITH A MAGNITUDE OF 1018 MB. EAST OF THE HIGH 
PRESSURE A SURFACE TROUGH EXTENDS FROM 30N60W 26N66W 24N72W 
25N80W THEN ACROSS SOUTHERN FLORIDA TO THE EASTERN GULF. 
ISOLATED SHOWERS ARE POSSIBLE WITHIN 25 NM EITHER SIDE OF THE 
AXIS W OF 69W. EAST OF THE TROUGH...A COLD FRONT EXTENDS FROM 
30N55W 25N62W TO 21N68W WHERE IT TRANSITIONS TO A DISSIPATING 
COLD FRONT TO 20N70W AND THEN A SURFACE TROUGH TO 20N75W. 
SCATTERED SHOWERS ARE WITHIN 175 NM EAST OF THE COLD FRONT N OF 
23N. A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH SPREADS OVER THE 
CENTRAL AND EASTERN ATLC N OF 15N. OVER THE FAR EASTERN ATLC A 
COLD FRONT EXTENDS FROM 30N10W TO 23N21W WHERE IT TRANSITIONS TO 
A DISSIPATING BOUNDARY ALONG 21N26W 20N32W. THE SATELLITE 
COMPOSITE OF TOTAL PRECIPITABLE WATER INDICATE THAT THERE IS NO 
PRECIPITATION ASSOCIATED TO THIS FRONTAL BOUNDARY. 

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

$$
NR