Atlantic Tropical Weather Discussion

000
AXNT20 KNHC 220550
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0500 UTC.

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS FROM 7N37W THROUGH A WEAK 1011 MB LOW NEAR 
4N29W TO 1N40W 5-10 KT. WAVE WAS RELOCATED EARLIER TODAY TO 
COINCIDE WITH THE SURFACE CIRCULATION. WAVE IS EMBEDDED WITHIN A 
LOW AMPLITUDE MOISTURE MAXIMUM ON THE TOTAL PRECIPITABLE WATER 
IMAGERY. THIS WAVE CONTINUES TO DISRUPTS THE ITCZ. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-6N BETWEEN 38W-
41W. CLUSTERS OF ISOLATED MODERATE CONVECTION DOT THE AREA FROM 
4N-7N BETWEEN 33W-38W. 

TROPICAL WAVE EXTENDS FROM 18N69W TO INLAND OVER SOUTH AMERICA 
TO NEAR 10N70W MOVING W-NW AT 15-20 KT OVER THE PAST 24 HOURS. 
WAVE IS EMBEDDED WITHIN A WEAK MOISTURE MAXIMUM ON THE TOTAL 
PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS AND POSSIBLE 
ISOLATED THUNDERSTORMS DOT THE CARIBBEAN FROM 15N-18N BETWEEN 
64W-71W. 

...ITCZ/MONSOON TROUGH...                                     
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL 
ATLC NEAR 11N15W CONTINUING TO 8N19W WHERE THE ITCZ BEGINS AND 
CONTINUES ALONG 5N28W TO 5N36W. SCATTERED MODERATE/ISOLATED 
CONVECTION IS OFF THE COAST OF AFRICA FROM 7N-9N BETWEEN 14W-
17W. CLUSTERS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS 
ARE WITHIN 30 NM OF THE MONSOON TROUGH/ITCZ E OF 24W TO THE 
COAST OF AFRICA.   

...DISCUSSION...

GULF OF MEXICO...                                                
A BROAD UPPER RIDGE AXIS EXTENDS FROM THE E PACIFIC REGION 
ACROSS S MEXICO/W YUCATAN PENINSULA TO THE N GULF COAST NEAR 
MOBILE ALABAMA COVERING THE ENTIRE GULF. A SURFACE RIDGE EXTENDS 
FROM THE W ATLC TO OVER THE FLORIDA PENINSULA WITH S TO SE 
RETURN FLOW COVERING THE GULF. WATER VAPOR IMAGERY INDICATES 
STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT DOMINATING THE E 
GULF. THE UPPER RIDGE IS DRAWING MOISTURE ACROSS MEXICO TO OVER 
THE W GULF. LOW LEVEL CLOUDS ARE OVER THE W GULF N OF 22N W OF 
93W LEAVING THE REMAINDER OF THE GULF UNDER CLEAR SKIES TONIGHT. 
ISOLATED SHOWERS ARE POSSIBLE WITHIN 30 NM OF S FLORIDA AND THE 
FLORIDA KEYS. COLD FRONT WILL MOVE INTO NE GULF LATE FRI THEN 
DRIFT SE THROUGH SUN. 

CARIBBEAN SEA...                                               
AN UPPER RIDGE AXIS EXTENDS ALONG THE N PORTION OF SOUTH AMERICA 
GIVING THE SW CARIBBEAN S OF 12N SW FLOW ALOFT. THE UPPER RIDGE 
OVER THE GULF OF MEXICO DIPS OVER THE NW CARIBBEAN GIVING THE 
AREA N OF 16N W OF 80W NW FLOW ALOFT WHILE THE REMAINDER OF THE 
AREA IS UNDER NEAR ZONAL WESTERLY FLOW ALOFT. THE MONSOON TROUGH 
EXTENDS FROM COLOMBIA NEAR 10N75W THROUGH A 1009 MB LOW NEAR 
11N80W TO ACROSS COSTA RICA NEAR 10N83W ARE GENERATING SCATTERED 
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 12N BETWEEN 74W-
80W AND S OF 10N W OF 80W. CLUSTERS OF SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS CONTINUE OVER THE N/CENTRAL CARIBBEAN N 
OF 18N BETWEEN 75W-80W. THE E CARIBBEAN IS COVERED IN THE 
TROPICAL WAVE SECTION ABOVE. W ATLC SURFACE RIDGE WILL MAINTAIN 
MODERATE TO FRESH SE TRADE WINDS IN GULF OF HONDURAS WITH 
STRONGER NE WINDS JUST W OF WAVE AXIS AND OFF COAST OF COLOMBIA 
THROUGH SUN. 

HISPANIOLA...                                           
AFTERNOON THUNDERSTORMS HAVE COMPLETELY DIED OUT. AN UPPER RIDGE 
BEGINS JUST TO THE NE TO THE ISLAND EXTENDING NW OVER THE W 
ATLC. WATER VAPOR IMAGERY SHOWERS DEEP LAYER MOISTURE OVER THE 
ISLAND SO SOME ISOLATED SHOWERS ARE POSSIBLE OVER THE INTERIOR 
SECTIONS OF THE ISLAND. THE UPPER RIDGE IS JUST TO THE E OF AN 
UPPER TROUGH THAT IS MOVING E. THE TROPICAL WAVE TO THE S 
CONTINUES TO TRACK W. THIS COULD BRING HEAVY RAIN MAINLY TO 
HAITI OVER THE NEXT DAY OR SO. 

ATLANTIC OCEAN...                                               
A SHORTWAVE UPPER TROUGH EXTENDS FROM AN UPPER LOW NEAR 32N78W 
OVER THE BAHAMA ISLANDS TO OFF THE COAST OF CUBA NEAR 21N75W AND 
IS AMPLIFYING AN UPPER RIDGE THAT EXTENDS FROM N OF PUERTO RICO 
NEAR 20N66W NW TO BEYOND 32N75W. THIS IS ENHANCING SCATTERED 
SHOWERS/ISOLATED THUNDERSTORMS OVER THE BAHAMAS FROM 22N-27N 
BETWEEN 75W-79W. A SURFACE RIDGE EXTENDS FROM A 1025 MB HIGH 
NEAR 32N58W TO OVER FLORIDA AND ALONG THE EASTERN SEABOARD. A 
BROAD UPPER TROUGH COVERS THE CENTRAL ATLC SUPPORTING A COLD 
FRONT THAT ENTERS THE REGION NEAR 32N43W TO 28N49W WHERE IT 
DISSIPATES TO 27N56W. SCATTERED SHOWERS ARE WITHIN 120 NM E OF 
THE FRONT N OF 30N. A WEAK SURFACE TROUGH IS TO THE S EXTENDING 
FROM 29N47W TO 25N49W. A BROAD SURFACE RIDGE COVERS THE E ATLC 
ANCHORED BY A 1036 MB HIGH WELL N OF THE AZORES. A WEAK TROUGH 
DEVELOPS OFF NE FLORIDA N OF GRAND BAHAMA THU. COLD FRONT WILL 
MOVE INTO NW PORTION FRI AND DRIFT IN E ACROSS WATERS N OF 27N 
THROUGH SUN.

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

$$
PAW