618 
AXNT20 KNHC 230002
TWDAT 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
805 PM EDT WED MAY 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS FROM 13N80W TO 07N81W MOVING W AT 10 TO 13 
KT. THIS WAVE IS CLEARLY DETECTABLE IN THE 700 MB WIND 
STREAMLINES OF THE GFS MODEL AND TOTAL PRECIPITABLE WATER 
IMAGERY INDICATES NEAR MAXIMUM TO MAXIMUM VALUES IN THE VICINITY 
OF ITS AXIS. SCATTERED MODERATE CONVECTION IS OCCURRING S OF 14N 
BETWEEN 74W AND 84W.

TROPICAL WAVE EXTENDS FROM 05N43W TO 02S45W MOVING W AT 5 TO 7 
KT. THE WAVE IS LOCATED ON THE WESTERN EXTENT OF THE ITCZ AND 
COINCIDES WITH AN AREA OF NEAR TO MAXIMUM TOTAL PRECIPITABLE 
WATER. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS 
LOCATED FROM 0N TO 06N BETWEEN 42W AND 48W.

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N14W TO 
08N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 
08N18W TO 02N30W TO 01N43W. WIDELY SCATTERED MODERATE CONVECTION 
IS FROM 01N TO 10N BETWEEN 20W AND 30W...FROM 01N TO 07N BETWEEN 
34W AND 41W...AND FROM 06S TO 00N BETWEEN 22W AND 41W.  

...DISCUSSION...

GULF OF MEXICO...                                                
AS OF 2100 UTC...SURFACE RIDGING DOMINATES THE GULF WATERS 
ANCHORED BY A 1014 MB HIGH LOCATED NE OF THE BASIN NEAR 29N84W. 
THIS SURFACE RIDGE IS BEING SUPPORTED BY MIDDLE TO UPPER LEVEL 
RIDGING ACROSS THE BASIN. A STATIONARY FRONT ACROSS THE LOWER 
MISSISSIPPI VALLEY AND SOUTHERN PLAINS ALONG WITH AN ASSOCIATED  
PREFRONTAL TROUGH CONTINUES TO GENERATE SHOWERS AND ISOLATED 
THUNDERSTORMS WITHIN 45 NM OFF THE LOUISIANA COAST BETWEEN 89W 
AND 92W. THE AXIS OF A OF A MIDDLE TO UPPER LEVEL SHORTWAVE 
TROUGH IS EAST OF THE EAST FLORIDA COAST FROM 25N TO 30N. THIS 
IS SUPPORTING A SURFACE TROUGH ANALYZED ACROSS THE FLORIDA 
PENINSULA TO THE FLORIDA KEYS ALONG 29N80W TO 25N81W TO 24N81W. 
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OBSERVED IN 
RADAR IMAGERY OVER THE FLORIDA PENINSULA AS WELL AS THE STRAITS 
OF FLORIDA. MAINLY S-SE WINDS OF 5 TO 10 KT ARE ACROSS THE BASIN 
AND FAIR WEATHER DOMINATES EXCEPT FOR THE REGIONS MENTIONED 
ABOVE. SURFACE RIDGING IS EXPECTED TO REMAIN ACROSS THE BASIN 
WITHIN THE NEXT 24 HOURS AS THE CENTER OF HIGH PRESSURE DRIFTS 
NW TO THE N CENTRAL GULF. 

CARIBBEAN SEA...                                           
A TROPICAL WAVE IS IN THE SW CARIBBEAN AS DESCRIBED IN THE 
TROPICAL WAVES SECTION ABOVE. ACROSS THE REST OF THE CARIBBEAN 
AND AT THE SURFACE TRADEWINDS IN THE RANGE OF 5 TO 15 KT 
DOMINATES W OF 68W WHILE TRADEWINDS OF 15 TO 20 KT SPREAD E OF 
THAT MERIDIAN DUE TO A TIGHTER PRESSURE GRADIENT. IN THE MIDDLE 
TO UPPER LEVELS...THE RIDGE OVER THE GULF EXTENDS TO THE WESTERN 
CARIBBEAN N OF 15N W OF 70W WHERE FAIR WEATHER CONDITIONS ARE 
ALSO OBSERVED. EAST OF 70W...NEAR WESTERLY MIDDLE TO UPPER LEVEL 
WINDS ASSOCIATED TO A WEAK TROUGH DOMINATE. MOISTURE FROM THE E 
PACIFIC MONSOON TROUGH IS BEING ADVECTED TO THIS REGION  
SUPPORTING SCATTERED SHOWERS ACROSS THE EASTERN CARIBBEAN.  
EASTERLY TRADES ARE EXPECTED TO CONTINUE DURING THE NEXT 24 
HOURS WHILE THE TROPICAL WAVE DRIFTS WESTWARD TOWARDS THE E 
PACIFIC BASIN. 

HISPANIOLA...                                                  
THE AXIS OF A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS EAST OF 
THE EAST FLORIDA COAST FROM 25N TO 30N. WATER VAPOR IMAGERY 
SHOWS MODERATE TO HIGH MOISTURE EXTENDING TO LA HISPANIOLA 
ASSOCIATED TO THIS MIDDLE TO UPPER LEVEL FEATURE. TOTAL 
PRECIPITABLE WATER IMAGERY SHOWS MODERATE MOISTURE OVER THE 
ISLAND WHICH MAY BE ENHANCING SCATTERED SHOWERS THIS EVENING. E-
SE TRADEWINDS OF 5 TO 15 KT CONTINUE AT THE SURFACE.

ATLANTIC OCEAN...                                               
THE AXIS OF A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS EAST OF 
THE EAST FLORIDA COAST FROM 25N TO 30N SUPPORTING A SURFACE 
TROUGH THAT EXTENDS FROM 28N80W TO 28N80W AND THEN ACROSS 
SOUTHERN FLORIDA TO KEY WEST. WATER VAPOR IMAGERY SHOWS MODERATE 
TO HIGH MOISTURE OVER THE W ATLC WHICH IS ENHANCING SHOWERS AND 
THUNDERSTORMS OVER THE BAHAMAS FROM 25N TO 27N W OF 77W. OVER 
THE CENTRAL ATLC...A MIDDLE TO UPPER LEVEL TROUGH N OF 30N IS 
SUPPORTING THE TAIL OF A STATIONARY FRONT EXTENDING FROM 30N40W 
TO 26N43W. SCATTERED SHOWERS ARE OBSERVED N OF 28N BETWEEN 34W 
AND 37W. THE REMAINDER OF THE ATLC N OF 20N IS UNDER THE 
INFLUENCE OF SURFACE RIDGING.

NOTE...A GOES-E/GOES-13 ANOMALY OCCURRED LAST NIGHT PRIOR TO 
FROM THIS SATELLITE...AND IS LIMITING CONFIDENCE IN SATELLITE 
INTERPRETATION ACROSS THE REGION BETWEEN APPROXIMATELY 60W AND 
100W. NESDIS ENGINEERS ARE WORKING ON RECOVERY EFFORTS AT THIS 
TIME.

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

$$
RAMOS