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Atlantic Tropical Discussion

Active Tropical Systems Basin Outlooks Satellite
Atlantic Basin Tropical Discussion
 
152 
AXNT20 KNHC 200005
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE AUG 19 2014

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
2345 UTC.

...SPECIAL FEATURES...

A TROPICAL WAVE IS ABOUT 300 NM EAST OF THE LESSER ANTILLES 
ASSOCIATED WITH A 1009 MB LOW EMBEDDED IN THE MONSOON TROUGH. 
HIGH DEEP LAYER MOISTURE ALONG WITH A MIDDLE TO UPPER LEVEL 
DIFFLUENT ENVIRONMENT IS SUPPORTING SCATTERED MODERATE 
CONVECTION AND ISOLATED TSTMS FROM 7N-13N BETWEEN 48W-55W. DRY 
SAHARAN AIR AND DUST ARE PRESENT IN THE NORTHERN WAVE 
ENVIRONMENT...WHICH IS HINDERING CONVECTION N OF 13N. 
ENVIRONMENTAL CONDITIONS ARE FORECAST TO BE MORE CONDUCIVE FOR 
GRADUAL DEVELOPMENT OF THIS SYSTEM DURING THE NEXT FEW DAYS AS 
IT APPROACHES THE LESSER ANTILLES AND MOVES INTO THE CARIBBEAN 
SEA. MEDIUM CHANCE OF DEVELOPMENT IS EXPECTED THROUGH 48 HOURS. 
SEE LATEST NHC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS 
MIATWOAT/ABNT20 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...                                     

A TROPICAL WAVE CAME OFF THE WESTERN AFRICAN COAST EARLIER THIS 
AFTERNOON WITH A WELL-DEFINED AXIS ALONG 18W. MOSTLY MEDIUM DEEP 
LAYER MOISTURE IS ASSOCIATED WITH THIS SYSTEM WHICH ALONG UPPER-
LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE CONVECTION AND 
ISOLATED TSTMS FROM 13N-17N E OF 20W. SAHARAN DRY AIR ENGULFS 
THE NORTHERN PORTION OF THE WAVE...THUS DEVOIDING OF CONVECTION 
THE REGION OF THE WAVE N OF 17N.

A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AXIS EXTENDING 
FROM 24N39W TO 12N39W...MOVING W AT 15 KT. NORTH OF 14N THE WAVE 
IS BEING AFFECTED BY THE DRY SAHARAN AIR LAYER WHICH IS 
HINDERING CONVECTION IN THAT PORTION OF THE WAVE. SCATTERED 
MODERATE CONVECTION IS CONFINED WITHIN 200 NM SOUTHWEST OF THE 
WAVE AXIS FROM 12N-14N BETWEEN 39W-42W. 

A TROPICAL WAVE IS NEAR 51W. SEE THE SPECIAL FEATURES SECTION OF 
THE DISCUSSION. 
 
A TROPICAL WAVE IS MOVING ACROSS THE YUCATAN 
PENINSULA...GUATEMALA AND THE EASTERN PACIFIC WATERS WITH AXIS 
EXTENDING FROM 22N88W TO 8N92W...MOVING W AT 15-20 KT. SCATTERED 
HEAVY SHOWERS AND THUNDERSTORMS ARE MAINLY INLAND WITH SOME OF 
THE CONVECTION ENTERING THE EASTERN BAY OF CAMPECHE. 

...ITCZ/MONSOON TROUGH...                                     

THE MONSOON TROUGH BEGINS WEST OF A TROPICAL WAVE NEAR 14N21W AND 
CONTINUES ALONG 13N39W TO A 1009 MB LOW NEAR 9N51W TO 8N61W. 
BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE 
SECTION...ISOLATED MODERATE CONVECTION IS FROM 10N-14N BETWEEN 
24W-35W.

...DISCUSSION... 

GULF OF MEXICO...                                               

WEAK SURFACE RIDGING ACROSS NORTHEASTERN GULF OF MEXICO IS 
SUPPORTING MAINLY 5 TO 10 KT ANTICYCLONIC WINDS WITH THE 
EXCEPTION OF THE EASTERN BAY OF CAMPECHE WHERE 15 KT WINDS ARE 
NOTED IN A SCATTEROMETER PASS AHEAD OF A TROPICAL WAVE TO MOVE 
INTO THE SW GULF LATER TONIGHT. THE NORTHERN PORTION OF THIS 
TROPICAL WAVE IS ALREADY ENHANCING SCATTERED HEAVY SHOWERS AND 
THUNDERSTORMS ACROSS THE YUCATAN PENINSULA WHICH ARE BEGINNING 
TO SPREAD INTO THE EASTERN BAY OF CAMPECHE. WEAK UPPER LEVEL 
DIFFLUENCE IS SUPPORTING ISOLATED MODERATE CONVECTION ACROSS THE 
WEST CENTRAL GULF FROM 24N-26N BETWEEN 90W-93W. ADDITIONAL 
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED OVER THE BAY OF 
CAMPECHE THROUGH WED MORNING AS THE TROPICAL WAVE CONTINUES TO 
MOVE WESTWARD. SURFACE RIDGING WILL DOMINATE ELSEWHERE WITHIN 
THE NEXT THREE DAYS.

CARIBBEAN SEA...                                                

MAINLY 10 TO 25 KT TRADEWINDS ARE OVER THE CARIBBEAN SEA. BASED 
ON A SCATTEROMETER PASS...THE STRONGEST WINDS ARE OCCURRING 
ACROSS THE SOUTHWESTERN BASIN S OF 15N. AN UPPER-LEVEL 
DIFFLUENCE PATTERN ALONG WITH DEEP LAYER MOISTURE SUPPORT 
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS S OF 15N W OF 
77W...INCLUDING NICARAGUA...COSTA RICA AND PANAMA. AN UPPER 
LEVEL LOW IS CENTERED NE OF THE LEEWARD ISLANDS WHICH ALONG A 
PATCH OF LOW-LEVEL MODERATE MOISTURE SUPPORT ISOLATED TO 
SCATTERED SHOWERS ACROSS PUERTO RICO AND THE VIRGIN ISLANDS. THE 
UPPER-LEVEL LOW NE OF THE LEEWARD ISLANDS ALONG WITH ANOTHER 
UPPER-LEVEL LOW ON THE NW CARIBBEAN IS GENERATING A DIFFLUENT 
ENVIRONMENT OVER HISPANIOLA. THIS ENVIRONMENT ALOFT ALONG WITH 
MODERATE/HIGH DEEP LAYER MOISTURE SUPPORT SCATTERED HEAVY 
SHOWERS AND TSTMS OVER WESTERN DOMINICAN REPUBLIC...HAITI AND 
ADJACENT WATERS. ELSEWHERE...FAIR WEATHER DOMINATE BEING 
INFLUENCED BY A DRY SAHARAN AIRMASS MOVING ACROSS THE REGION. 
DUST AND HAZE ARE BEING REPORTED BY SEVERAL LOCATIONS ACROSS THE 
CENTRAL AND EASTERN BASIN. THE NEXT TROPICAL WAVE IS FORECAST TO 
ENTER THE EASTERN CARIBBEAN BY FRI MORNING.  

...HISPANIOLA...                                         

AN UPPER-LEVEL LOW CENTERED NE OF THE LEEWARD ISLANDS ALONG WITH 
ANOTHER UPPER-LEVEL LOW ON THE NW CARIBBEAN IS GENERATING A 
DIFFLUENT ENVIRONMENT OVER HISPANIOLA. THIS ENVIRONMENT ALOFT 
ALONG WITH MODERATE/HIGH DEEP LAYER MOISTURE SUPPORT SCATTERED 
HEAVY SHOWERS AND TSTMS OVER WESTERN DOMINICAN REPUBLIC...HAITI 
AND ADJACENT WATERS. SHOWERS ARE EXPECTED TO CONTINUE DURING THE 
NEXT 24 HOURS.

ATLANTIC OCEAN...                                              

MODERATE LOW-LEVEL MOISTURE ASSOCIATED WITH THE PASSAGE OF THE 
TROPICAL WAVE CURRENTLY MOVING ACROSS THE YUCATAN  PENINSULA IS 
ENHANCING SCATTERED/ISOLATED SHOWERS ON THE FLORIDA STRAITS...AS 
WELL AS THE NORTHERN AND CENTRAL BAHAMAS. OTHERWISE...BESIDES 
THE TROPICAL WAVES ALREADY DISCUSSED...THE REMAINDER BASIN IS UNDER 
THE INFLUENCE OF SURFACE RIDGING BEING ANCHORED BY A 1024 MB 
HIGH NEAR 35N34W AND A 1019 MB HIGH NEAR 26N66W.

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

$$
NAR/ASL