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Atlantic Tropical Weather Discussion (Text)



000
AXNT20 KNHC 281026
TWDAT 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
805 AM EDT THU MAY 28 2015

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
1015 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS W OF THE ITCZ FROM 5N TO 14N WITH AXIS NEAR 
54W/55W...MOVING W AT 15-20 KT DURING THE LAST 24 HOURS. SSMI 
TPW IMAGERY SHOW THE WAVE CONTINUES EMBEDDED WITHIN ABUNDANT 
MOISTURE IN THE MIDDLE TO LOWER LEVELS. SATELLITE DERIVED WINDS 
AND MODEL GUIDANCE SHOW A DIVERGENT ENVIRONMENT ALOFT THAT 
SUPPORT SCATTERED MODERATE CONVECTION FROM 04N TO 15N BETWEEN 
50W AND 60W. FURTHER CONVECTION IS BEING HINDERED IN PART BY 
STRONG DEEP LAYER WIND SHEAR IN THIS REGION OF THE TROPICAL ATLC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL 
ATLANTIC NEAR 08N13W TO 06N20W. THE ITCZ BEGINS NEAR 06N20W AND 
CONTINUES ALONG 03N36W TO THE COAST OF NORTHERN BRAZIL NEAR 
00N50W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS 
FROM 02N TO 08N E OF 20W. SCATTERED MODERATE CONVECTION IS 
WITHIN 75 NM EITHER SIDE OF THE ITCZ. FOR CONVECTION ASSOCIATED 
WITH THE TROPICAL WAVE SEE THE SECTION ABOVE.

...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE OVER MEXICO EXTENDS E-SE TO THE GULF OF 
CAMPECHE WHERE A SURFACE TROUGH IS ANALYZED FROM 22N92W TO 
16N94W WITH NO CONVECTION ASSOCIATED WITH IT. BROAD SURFACE HIGH 
PRESSURE OVER THE ATLANTIC CONTINUES TO EXTEND A RIDGE AXIS SW 
ACROSS THE FLORIDA PENINSULA AND INTO THE REMAINDER GULF. OVER 
THE N-NE BASIN...A FORMER SQUALL LINE WEAKENED LEAVING AN 
ELONGATED AREA OF LOW PRESSURE BEING SUPPORTED BY A SHORT-WAVE 
MIDDLE TO UPPER LEVEL TROUGH. ISOLATED SHOWERS AND TSTMS ARE N 
OF 26N BETWEEN 85W AND 89W. AN UPPER LEVEL LOW OVER THE SE GULF 
SUPPORTS SIMILAR CONVECTION S OF 26N E OF 86W. EASTERLY TO 
SOUTHEASTERLY WIND FLOW OF 10 TO 15 KT ASSOCIATED WITH THE RIDGE 
DOMINATES THE GULF...EXCEPT OVER THE STRAITS OF FLORIDA...THE 
YUCATAN CHANNEL AND ALONG THE WESTERN YUCATAN PENINSULA WHERE 
WINDS INCREASE TO 20 KT DUE TO A TIGHTER PRESSURE GRADIENT. 
STRONG DRY AIR SUBSIDENCE FROM ALOFT HAS DECREASED THE LOW LEVEL 
MOISTURE BEING ADVECTED TO THE BASIN...THUS FAVORING STABLE 
CONDITIONS AND FAIR WEATHER ELSEWHERE. SURFACE RIDGING WILL 
CONTINUE TO BE THE DOMINANT FEATURE DURING THE NEXT THREE DAYS.

CARIBBEAN SEA...

LOW PRESSURE OVER NORTHERN COLOMBIA AND A SLIGHTLY HIGHER 
PRESSURE ACROSS THE CARIBBEAN GENERATE A TIGHTER PRESSURE 
GRADIENT ALONG THE COAST OF COLOMBIA...RESULTING IN NE TO E 
WINDS OF 20 TO 25 KT FROM 11N TO 13N BETWEEN 74W AND 76W WITH 
SEAS TO 8 FT. ELSEWHERE...TRADES OF 10 TO 15 KT AND SEAS LESS 
THAN 8 FT DOMINATE. SSMI TPW IMAGERY SHOW PATCHES OF MODERATE 
LOW LEVEL MOISTURE ALONG THE NORTHERN BASIN SUPPORTING 
CLOUDINESS AND POSSIBLE ISOLATED SHOWERS OVER PUERTO RICO AND 
HISPANIOLA AND SCATTERED MODERATE CONVECTION AND TSTMS OVER CUBA 
SOUTHERN ADJACENT WATERS. SCATTERED MODERATE CONVECTION AND 
ISOLATED TSTMS ARE WITHIN 20 NM OFF THE COLOMBIA AND SOUTHERN 
PANAMA COASTS. ABUNDANT MOISTURE STARTS TO REACH THE WINDWARD 
ISLANDS ASSOCIATED WITH A TROPICAL WAVE FORECAST TO ENTER THE 
EASTERN BASIN BY FRIDAY NIGHT. FAIR WEATHER IS ELSEWHERE BEING 
SUPPORTED BY DEEP LAYER DRY AIR.

...HISPANIOLA...

MIDDLE TO UPPER LEVEL TROUGHING ALONG WITH SHALLOW MOISTURE OVER 
HISPANIOLA COASTAL WATERS SUPPORT CLOUDINESS AND POSSIBLE 
ISOLATED SHOWERS ACROSS THE ISLAND...INTENSIFYING IN THE 
AFTERNOON AND EARLY EVENING HOURS. HOWEVER...UPPER LEVEL 
SUBSIDENCE CONTINUE TO SUPPRESS THE FORMATION OF THUNDERSTORMS.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL LOW ANCHORED NEAR 25N62W CONTINUE TO 
SUPPORT A SURFACE TROUGH WITH AXIS EXTENDING FROM 31N62W TO A 
1015 MB LOW NEAR 25N66W. SCATTERED MODERATE CONVECTION AND 
ISOLATED TSTMS ARE N OF 25N BETWEEN 48W AND 61W. A TROPICAL WAVE 
IS W OF THE ITCZ. SEE THE TROPICAL WAVES SECTION ABOVE. 
ELSEWHERE SURFACE HIGH PRESSURE AND FAIR WEATHER PREVAILS. THE 
SURFACE TROUGH WILL REMAIN OVER THE SW N ATLC DURING THE NEXT 
THREE DAYS. SURFACE RIDGING WILL DOMINATE ELSEWHERE. THE 
TROPICAL WAVE WILL ENTER THE EASTERN CARIBBEAN BASIN FRIDAY 
NIGHT. 

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

$$
NR

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Page last modified: Thursday, 28-May-2015 10:27:02 UTC