000
AXNT20 KNHC 282353
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUN 28 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 15N44W THROUGH A WEAK 1015 MB LOW 
NEAR 13N44W TO 9N45W MOVING WNW NEAR 20 KT. WAVE IS EMBEDDED 
WITHIN A SURGE OF DEEP LAYER MOISTURE AS DEPICTED ON TOTAL 
PRECIPITABLE WATER IMAGERY. WAVE IS AT THE LEADING EDGE OF A 
DENSE LAYER OF THE SAHARAN DUST THAT COVERS THE TROPICAL ATLC 
FROM 13N-29N. SCATTERED SHOWERS ARE FROM 11N-15N BETWEEN 
43W-48W. 

THE TROPICAL WAVE IN THE CARIBBEAN HAS LOST ITS IDENTITY AND HAS 
BEEN ABSORBED BY THE INVERTED UPPER TROUGH. 

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL 
ATLC NEAR 13N16W TO 7N28W WHERE THE ITCZ AXIS CONTINUES ALONG 
5N34W 8N52W TO INLAND OVER SOUTH AMERICA NEAR 7N59W. CLUSTERS OF 
SCATTERED MODERATE CONVECTION ARE WITHIN 120 NM EITHER SIDE OF 
THE ITCZ BETWEEN 35W-45W. 

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE DOMINATES ALL BUT THE FAR E GULF ANCHORED NEAR 
23N93W. THE UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO 
GENERATE SCATTERED SHOWERS/THUNDERSTORMS OVER THE W GULF FROM 
21N-26N BETWEEN 91W-95W. THE FAR E GULF IS UNDER AN UPPER TROUGH 
THAT IS SUPPORTING A SURFACE TROUGH THAT AT 28/2100 UTC EXTENDS 
FROM THE W ATLC FRONT THROUGH THE STRAITS OF FLORIDA NEAR 24N80W 
TO 23N85W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF THE 
TROUGH TO INLAND OVER CUBA. ISOLATED CLUSTERS OF SHOWERS AND 
THUNDERSTORMS ARE WITHIN 60 NM N OF THE TROUGH AND S OF 23N 
BETWEEN 85W-87W. A WEAK SURFACE RIDGE HAS ESTABLISHED OVER THE E 
GULF WITH A 1019 MB HIGH NEAR 27N86W LEAVING THE REMAINDER OF 
THE GULF UNDER CLEAR SKIES THIS EVENING. SE RETURN FLOW WILL 
INCREASE OVER THE FAR W GULF SUN THROUGH MON. THE RIDGE WILL 
REMAIN ALONG 27N/28N THROUGH TUE. 

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE NW CARIBBEAN 
W OF A LINE FROM CUBA NEAR 20N77W TO HONDURAS NEAR 16N84W WHERE 
AN INVERTED UPPER TROUGH EXTENDS FROM COSTA RICA/NICARAGUA 
BORDER TO HAITI. A SECOND UPPER RIDGE COVERS THE E CARIBBEAN AND 
IS ANCHORED NEAR THE ABC ISLANDS. MODERATE TO FRESH E TO SE 
TRADE WINDS ARE ACROSS THE BASIN WITH GALE FORCE WINDS ALONG THE 
N COAST OF SOUTH AMERICA. AFTERNOON THUNDERSTORMS HAVE DEVELOPED 
OVER THE GREATER ANTILLES FROM PUERTO RICO TO CUBA AND WITH THE 
EASTERLY SURFACE FLOW AND THE NE FLOW ALOFT IS MOVING THE STORMS 
INTO THE CARIBBEAN WATERS. THE MONSOON TROUGH EXTENDS ACROSS THE 
SW CARIBBEAN FROM COLOMBIA NEAR 8N76W ACROSS PANAMA INTO THE E 
PACIFIC REGION OVER COAST RICA NEAR 10N84W GENERATING SCATTERED 
SHOWERS/THUNDERSTORMS S OF 12N BETWEEN COLOMBIA AND NICARAGUA. 
THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER CLEAR SKIES 
THIS EVENING. THE TRADE WINDS WILL PREVAIL ACROSS THE CARIBBEAN 
THROUGH MON. A TROPICAL WAVE WILL MOVE INTO THE CARIBBEAN LATE 
SUN OR EARLY MON AND REACH THE CENTRAL CARIBBEAN TUE.

ATLANTIC OCEAN...
AN UPPER TROUGH COVERS THE W ATLC N OF 25N W OF 68W INTO THE FAR 
E GULF OF MEXICO NEAR 82W SUPPORTING A COLD FRONT THAT AT 
28/2100 UTC ENTERS THE REGION FROM A 997 MB LOW...REMNANTS OF 
DEBBY...CENTERED NEAR 32N70W ALONG 27N75W TO 25N79W WHERE A 
SURFACE TROUGH CONTINUES THROUGH THE STRAITS OF FLORIDA INTO THE 
GULF OF MEXICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE 
WITHIN 180 NM E OF THE FRONT/TROUGH. AN UPPER LOW IS IN THE 
CENTRAL ATLC NEAR 25N52W GENERATING SCATTERED SHOWERS AND 
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM 
28N50W TO 21N61W. A BROAD SURFACE RIDGE DOMINATES THE REMAINDER 
OF THE ATLC W OF 70W WITH A WEAKNESS IN THE CENTRAL ATLC WHERE A 
WEAK SURFACE TROUGH EXTENDS FROM 27N43W TO 23N50W. THE SURFACE 
RIDGE IS ANCHORED BY A 1030 MB HIGH WNW OF THE AZORES. SATELLITE 
IMAGERY CONTINUES TO SHOW AN AREA OF SAHARAN DUST COVERING THE 
TROPICAL ATLC FROM 13N-29N E OF 44W AND STREAMING N ALONG THE 
COAST OF AFRICA TO INLAND OVER SPAIN AND PORTUGAL. W ATLC COLD 
FRONT WILL SHIFT E OF 65W FRI AND DISSIPATE. SURFACE RIDGE WILL 
BUILD S OF THE REMNANTS OF DEBBY THROUGH TUE.

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

$$
PAW