000
AXNT20 KNHC 011146
TWDAT 

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

...TROPICAL WAVES...                                     
TROPICAL WAVE IS OFF THE COAST OF W AFRICA ALONG 18W FROM 5N-20N 
MOVING W NEAR 15 KT. WAVE IS EMBEDDED WITHIN A SURGE OF DEEP 
MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. NO 
ASSOCIATED DEEP CONVECTION. 
 
TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS ALONG 45W/46W FROM 
6N-12N MOVING W 10-15 KT. WAVE IS ALONG THE LEADING EDGE OF A 
SURGE OF MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER 
IMAGERY. NO ASSOCIATED DEEP CONVECTION. 

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL 
ATLC NEAR 17N16W CONTINUING ALONG 9N23W TO 5N31W WHERE THE ITCZ 
BEGINS AND CONTINUES ALONG 4N33W 6N40W TO 4N50W. CLUSTERS OF  
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE N OF 3N TO THE 
SW COAST OF AFRICA E OF 6W TO THE PRIME MERIDIAN...WITHIN 120 NM 
OF LINE FROM 5N11W TO 6N19W...WITHIN 150 NM OF LINE FROM 4N20W 
TO 7N31W...AND WITHIN 90/120 NM OF LINE FROM 7N36W TO 8N57W. 

...DISCUSSION...

GULF OF MEXICO...                                               
A BROAD UPPER RIDGE COVERS THE GULF S OF 28N E OF 94W WITH NEAR 
ZONAL WESTERLY FLOW ALOFT ELSEWHERE. A SURFACE RIDGE EXTENDS 
FROM THE W ATLC OVER THE SE CONUS GIVING THE GULF SE SURFACE 
FLOW. N OF THE UPPER RIDGE IS STRONG SUBSIDENCE AND DRY STABLE 
AIR ALOFT WITH TROPICAL MOISTURE BEING DRAWN ACROSS THE SE GULF 
BY THE UPPER RIDGE AND IS PROVIDING DIFFLUNCE ALOFT TO GENERATE 
SCATTERED SHOWERS S OF LINE FROM NAPLES FLORIDA ALONG 24N90W TO 
23N96W AND ISOLATED THUNDERSTORMS IN THE BAY OF CAMPECHE S OF 
21N BETWEEN 91W-96W. THE REMAINDER OF THE GULF IS UNDER WITH 
MOSTLY CLEAR SKIES THIS MORNING. SURFACE RIDGE WILL DRIFT E 
THROUGH TUE. A SURFACE TROUGH WITH AN EMBEDDED LOW IS EXPECTED 
TO FORM AND LINGER IN THE S/CENTRAL GULF SUN AND MON. THE TROUGH 
WILL BECOME MORE ELONGATED NE TO SW AND DRIFT E TOWARDS THE 
YUCATAN PENINSULA TUE AND WED. A WEAK COLD FRONT IS EXPECTED TO 
MOVE INTO THE FAR NW GULF LATE SUN THEN REACH FROM NEAR THE W 
FLORIDA PANHANDLE TO 28N93W THEN DRIFT N AND INLAND TUE AND WED.

CARIBBEAN SEA...                                                 
THE UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE W CARIBBEAN W 
OF 69W AND IS PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED 
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 18N BETWEEN 77W-
85W. THE MONSOON TROUGH EXTENDS INLAND FROM OVER CENTRAL AMERICA 
WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND WITHIN 
45 NM ALONG THE COAST OF PANAMA W OF 80W AND COSTA RICA. 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 120 NM OF 
LINE FROM 13N78W TO INLAND OVER COLOMBIA NEAR 11N75W WITH A 
NARROWER BAND WITHIN 45 NM OF LINE FROM 13N78W TO 17N84W. ATLC 
SURFACE RIDGE WILL MAINTAIN MODERATE TO FRESH TRADE WINDS ACROSS 
MUCH OF THE BASIN THROUGH MON BEFORE SHIFTING SLOWLY E ON TUE. A 
TROPICAL WAVE WILL MOVE INTO THE E CARIBBEAN TUE AND IT WILL 
DISSIPATE WED.

HISPANIOLA...                                                
WEAK LOW/MID LEVEL TROUGHING EXTENDS FROM THE SW ATLC TO OVER 
HISPANIOLA. LOW LEVEL MOISTURE WILL REMAIN ACROSS THE ISLAND AND 
COULD REGENERATE SCATTERED SHOWERS WITH POSSIBLE ISOLATED 
THUNDERSTORMS THIS AFTERNOON. 

ATLANTIC OCEAN...                                             
THE UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE SW ATLC S OF 
28N W OF 70W AND IS PROVIDING DIFFLUNCE ALOFT TO GENERATE 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 26N W OF 72W. THE 
REMAINDER OF THE W ATLC IS COVERED BY A LARGE UPPER TROUGH WITH 
THE UPPER LOW CENTERED NEAR 32N69W WITH A SHARP UPPER RIDGE JUST 
TO THE E EXTENDING FROM NEAR 18N60W ALONG 26N60W TO BEYOND 32N61W 
AND IS PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS 
AND POSSIBLE ISOLATED THUNDERSTORMS OVER A BROAD AREA FROM 23N 
TO BEYOND 32N BETWEEN 63W-70W. A WEAK SURFACE TROUGH IS ANALYZED 
FROM 31N56W TO 27N56W. A BROAD SURFACE RIDGE COVERS THE ENTIRE 
ATLC WITH A WEAKNESS IN THE VICINITY OF THE ABOVE SURFACE 
TROUGH. A 1026 MB HIGH IS IN THE W ATLC NE OF BERMUDA WITH A 
1034 MB HIGH IN THE E ATLC NE OF THE AZORES. ATLC RIDGE WILL 
REMAIN THROUGH MON BEFORE SHIFTING SLOWLY EASTWARD TUE. A WEAK 
TROUGH IS EXPECTED TO DEVELOP E OF THE BAHAMAS SUN AND MON AND 
DRIFT W THROUGH TUE. A WEAK COLD FRONT MAY APPROACH THE FAR NW 
CORNER OF THE AREA TUE.

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

$$ 
PAW