[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261015
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE MAY 26 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 THE EQUATOR TO 11N WITH
AXIS NEAR 44W...MOVING W AT 13 TO 15 KT DURING THE LAST 24
HOURS. SSMI TPW IMAGERY SHOW A DECREASE IN MOISTURE IN THE
IMMEDIATE WAVE ENVIRONMENT...THUS RESULTING IN A DECREASE OF
CONVECTION...ESPECIALLY ON THE NORTHERN AND EASTERN REGIONS OF
THE WAVE WHERE METEOSAT IMAGERY SHOW DUST AND DRY SAHARAN AIR.
SCATTERED MODERATE CONVECTION IS WITHIN 300 NM AHEAD OF THE WAVE
AXIS S OF 8N. ISOLATED MODERATE CONVECTION IS WITHIN 300 NM E OF
IT.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA REACHING THE TROPICAL
ATLANTIC NEAR 08N12W TO 04N16W. THE ITCZ BEGINS NEAR 04N16W AND
CONTINUES ALONG 04N27W TO EAST OF A TROPICAL WAVE NEAR 04N40W.
ISOLATED MODERATE CONVECTION AND TSTMS ARE WITHIN 200 NM EITHER
SIDE OF THE MONSOON TROUGH. ISOLATED MODERATE CONVECTION IS
WITHIN 200 NM N OF THE ITCZ W OF 33W. FOR CONVECTION ASSOCIATED
WITH THE TROPICAL WAVE SEE THE SECTION ABOVE.

...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE EXTENDING ACROSS CENTRAL U.S. AND MEXICO
EXTENDS INTO THE WESTERN GULF WHILE HIGH PRESSURE ANCHORED BY A
CENTER OF 1031 MB OVER THE NW ATLANTIC CONTINUES TO EXTEND A
RIDGE AXIS SW ACROSS THE FLORIDA PENINSULA INTO THE EASTERN
GULF. SOUTHEASTERLY WIND FLOW OF 15 TO 20 KT ASSOCIATED WITH THE
RIDGE COVERS THE GULF AND ADVECTS LOW LEVEL MOISTURE FROM THE SW
N ATLC WATERS AND THE NW CARIBBEAN. LOW LEVEL MOISTURE
CONVERGENCE ALONG THE N-NW GULF COASTLINE ALONG WITH A DIFFLUENT
ENVIRONMENT ALOFT SUPPORT HEAVY SHOWERS AND TSTMS ASSOCIATED
WITH A SQUALL LINE MOVING ACROSS SE LOUISIANA AND ADJACENT
WATERS N OF 28N BETWEEN 90W AND 93W. HAZE AND FOG IS ALSO BEING
REPORTED IN THE NW GULF N OF 26N W OF 90W. ISOLATED SHOWERS AND
TSTMS ARE OBSERVED OVER THE NE GULF N OF 28N E OF 84W. SURFACE
RIDGING WILL CONTINUE TO BE THE DOMINANT FEATURE DURING THE NEXT
THREE DAYS.

CARIBBEAN SEA...

BROAD SURFACE HIGH PRESSURE ACROSS THE ATLANTIC CONTINUES TO
EXTEND S INTO THE NORTHERN AND CENTRAL CARIBBEAN...THUS
SUPPORTING A TIGHTER PRESSURE GRADIENT IN THE SW
BASIN...RESULTING IN NE TO E WINDS OF 20 TO 25 KT FROM 11N TO
13N BETWEEN 73W AND 77W WITH SEAS RANGING FROM 8 TO 9 FT.
ELSEWHERE FROM 11N TO 14N BETWEEN 74W AND 81W WINDS ARE 20 KT OR
LESS WITH SEAS UP TO 9 FT IN E SWELL. OTHERWISE...S OF 18N W OF
85W E WINDS OF 20 TO 25 KT DOMINATE WITH SEAS LESS THAN 8 FT.
SSMI TPW IMAGERY SHOW MODERATE LOW LEVEL MOISTURE OVER THE NW
BASIN...WHICH ALONG WITH UPPER TROUGHING ALOFT SUPPORT ISOLATED
SHOWERS AND TSTMS OVER CUBA COASTAL WATERS AND SOUTHERN WINDWARD
PASSAGE. SHALLOW MOISTURE OVER THE NE CARIBBEAN SUPPORTS
SCATTERED TO ISOLATED SHOWERS OVER HAITI...THE MONA PASSAGE...
PUERTO RICO AND THE VIRGIN ISLANDS. FAIR WEATHER IS ELSEWHERE
BEING SUPPORTED BY DEEP LAYER DRY AIR. NO SIGNIFICANT CHANGES
ARE EXPECTED IN THE NEXT TWO DAYS.

...HISPANIOLA...

SHALLOW MOISTURE IS OVER HAITI ENHANCING ISOLATED SHOWERS FOR
THIS REGION OF THE ISLAND. DEEP LAYER DRY AIR IS OVER THE
REMAINDER ISLAND AS DEPICTED BY SSMI TPW AND WATER VAPOR
IMAGERY...THUS SUPPORTING FAIR WEATHER. SHOWERS AND
THUNDERSTORMS ACTIVITY ARE EXPECTED DURING THE AFTERNOON AND
EARLY EVENING HOURS THROUGH WED MORNING BEING ENHANCED BY
OROGRAPHIC LIFTING AND DAYTIME HEATING AND SUPPORTED BY MIDDLE
TO UPPER LEVEL TROUGHING.

ATLANTIC OCEAN...

A MIDDLE TO UPPER LEVEL LOW ANCHORED NEAR 30N58W CONTINUE TO
SUPPORT A SURFACE TROUGH WITH AXIS EXTENDING FROM 30N55W TO
23N61W. SCATTERED MODERATE CONVECTION AND TSTMS ARE N OF 23N
BETWEEN 50W AND 58W. 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 DRIFT TOWARDS THE
SW N ATLC DURING THE NEXT THREE DAYS. SURFACE RIDGING WILL
DOMINATE ELSEWHERE.

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

$$
NR
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