NHC Atlantic Tropical Weather Discussion

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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