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000
AXNT20 KNHC 280605
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC.


...TROPICAL WAVES...

A TROPICAL WAVE IS W OF THE ITCZ FROM 1N TO 14N WITH AXIS NEAR 54W...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 DIFFLUENT ENVIRONMENT ALOFT E OF THE WAVE AXIS THAT SUPPORT SCATTERED MODERATE CONVECTION FROM 03N TO 07N BETWEEN THE AXIS AND 50W. FURTHER CONVECTION IS BEING HINDERED MAINLY 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 09N13W TO 05N21W. THE ITCZ BEGINS NEAR 05N21W AND CONTINUES ALONG 04N37W TO THE COAST OF NORTHERN BRAZIL NEAR 01N50W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 03N TO 08N E OF 18W. SIMILAR CONVECTION IS WITHIN 60 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 22N89W TO 16N93W 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 FROM NORTHERN ALABAMA TO 30N88W TO 27N88W. A SHORT-WAVE MIDDLE TO UPPER LEVEL TROUGH GENERATES A DIFFLUENT ENVIRONMENT ALOFT THAT SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS N OF 26N BETWEEN 85W AND 88W. AN UPPER LEVEL LOW OVER THE SE GULF SUPPORTS SIMILAR CONVECTION FROM 24N TO 26N E OF 84W. 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 72W 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. FAIR WEATHER IS ELSEWHERE BEING SUPPORTED BY DEEP LAYER DRY AIR. A TROPICAL WAVE WILL MOVE ACROSS THE LESSER ANTILLES INTO THE EASTERN BASIN FRIDAY NIGHT.


...HISPANIOLA...

MIDDLE TO UPPER LEVEL TROUGHING ALONG WITH SHALLOW MOISTURE OVER HISPANIOLA COASTAL WATERS SUPPORT CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ACROSS THE ISLAND TONIGHT. HOWEVER...UPPER LEVEL SUBSIDENCE CONTINUE TO SUPPRESS THE FORMATION OF THUNDERSTORMS. EXPECT...SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS THURSDAY AFTERNOON AND EVENING ESPECIALLY OVER THE NORTH COAST OF HISPANIOLA.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL LOW ANCHORED NEAR 25N62W CONTINUE TO SUPPORT A SURFACE TROUGH WITH AXIS EXTENDING FROM 30N62W TO 25N66W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE N OF 25N BETWEEN 50W AND 64W. 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 PREVAIL OVER THE SW N ATLC DURING THE NEXT THREE DAYS. SURFACE RIDGING WILL DOMINATE ELSEWHERE. THE TROPICAL WAVE WILL ENTER THE EASTERN CARIBBEAN FRIDAY NIGHT.

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

$$ NR

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