Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 310000
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 30 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EARLIER ALONG 31W/32W WAS ADJUSTED TO THE WEST
BASED ON HOVMOLLER/EASTERLY WAVE DIAGNOSTICS AND NOW EXTENDS
FROM 09N35W TO 02N36W MOVING W AT 20 KT. THE WAVE REMAINS
LARGELY EMBEDDED WITHIN THE ITCZ AXIS AND COINCIDES WITH A
GLOBAL MODEL INDICATED 700 MB JET MAXIMUM TO THE EAST OF THE
AXIS IN THE VICINITY OF 06N30W. ONLY ISOLATED MODERATE
CONVECTION IS ASSOCIATED WITH WAVE AT THIS TIME.

A TROPICAL WAVE EXTENDS FROM 17N72W TO 12N72W MOVING W AT 15-20
KT. THE WAVE CONTINUES TO MOVE WITHIN THE SOUTHWESTERN PERIPHERY
OF A 700 MB RIDGE CENTERED OVER THE WESTERN ATLC. A MIDDLE TO
UPPER LEVEL TROUGH NOTED ON WATER VAPOR IMAGERY OVER THE WESTERN
AND CENTRAL CARIBBEAN SEA IS PRODUCING SOUTHWESTERLY SHEAR
ACROSS THE WAVE WITH UPPER LEVEL DIFFLUENCE OCCURRING IN THE
VICINITY OF THE WAVE AXIS. NO SIGNIFICANT CONVECTION WAS NOTED
IN ASSOCIATION WITH THE WAVE AT THIS TIME.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
08N18W. THE ITCZ AXIS EXTENDS FROM 08N18W TO 04N30W TO 04N40W TO
04N51W. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN
90-120 NM N OF THE AXIS BETWEEN 26W AND 32W...AND WITHIN 120 NM
N OF THE AXIS BETWEEN 44W AND 50W.

...DISCUSSION...

GULF OF MEXICO...

UPPER LEVEL RIDGE WAS NOTED OVER THE GULF ALONG 91W. WEST-
NORTHWESTERLY FLOW ALOFT WAS INDICATED OVER THE EASTERN GULF
BETWEEN THE RIDGE AND A DOWNSTREAM BROAD UPPER LEVEL TROUGH THAT
EXTENDS FROM SOUTH FLORIDA SOUTHWARD OVER THE WESTERN CARIBBEAN
ALONG 82W. A SHARP UPPER TROUGH OVER THE PLAINS CONTINUES TO
EJECT SHORTWAVE ENERGY AROUND THE BASE OF THE TROUGH OVER TEXAS.
CONVECTION ASSOCIATED WITH ONE SHORTWAVE IS OCCURRING OVER THE
COASTAL PLAINS OF TEXAS 60-75 NM INLAND OF THE GULF COAST. THE
NORTHERN PORTION OF THIS CONVECTION MAY MOVE OFF THE UPPER TEXAS
COAST TONIGHT. ADDITIONAL ISOLATED THUNDERSTORMS ARE WITHIN 50
NM OF THE COASTLINE OF LOUISIANA...SUPPORTED BY THE SHORTWAVE.
A WEAK SURFACE TROUGH WAS NOTED OVER THE FLORIDA PENINSULA
DIURNALLY DRIVEN BY DAYTIME HEATING. SCATTERED THUNDERSTORMS
OVER FLORIDA HAVE MOVED WESTWARD AND EXTEND FROM CEDAR KEY
SOUTHWARD TO NEAR NAPLES. A SECOND SURFACE TROUGH EXTENDS OVER
THE SOUTHWESTERN GULF FROM 23N93W TO 18N93W...MOVING WESTWARD.
EAST TO SOUTHEAST WINDS OF 5 TO 10 KT COVER THE NORTHERN GULF.
EASTERLY WINDS OF 10 TO 15 KT COVER THE SOUTHERN GULF. THE UPPER
TROUGH OVER THE PLAINS WILL CONTINUE TO DIG SOUTHEASTWARD WHICH
WILL BRING INCREASING CHANCES FOR CONVECTION OVER THE NORTHWEST
AND NORTH-CENTRAL GULF THROUGH SUNDAY.

CARIBBEAN SEA...

A BROAD UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER
THE WESTERN CARIBBEAN WITH AXIS ALONG 81W/82W. WEAK UPPER LEVEL
DIFFLUENCE IS SUPPORTING WIDELY SCATTERED THUNDERSTORMS OVER THE
EASTERN HALF OF CUBA. DEEP MOISTURE IS BEING TRANSPORTED AROUND
THE BASE OF THE TROUGH IN SOUTHWESTERLY FLOW ALOFT FROM THE
SOUTHWESTERN CARIBBEAN AND OVER THE CENTRAL AND EASTERN
CARIBBEAN INTO THE TROPICAL ATLANTIC. DIFFLUENCE ALOFT OVER THE
SOUTHWESTERN CARIBBEAN SUPPORTED EARLIER MODERATE TO STRONG
CONVECTION FROM 08N TO 13N BETWEEN 75W TO 80W. THIS CONVECTION
HAS SINCE WEAKENED. OROGRAPHICALLY DRIVEN POCKETS OF CONVECTIVE
ACTIVITY WERE OBSERVED OVER HIGHER TERRAIN OF COSTA
RICA...NICARAGUA AND HONDURAS. A TROPICAL WAVE IS OVER THE
CENTRAL CARIBBEAN. PLEASE SEE THE TROPICAL WAVES SECTION FOR
MORE DETAILS. TRADE WINDS OF 10 TO 15 KT COVER MOST OF THE
CARIBBEAN WITH 15 TO 20 KT NOTED OVER THE SOUTH-CENTRAL
CARIBBEAN WITHIN 90-120 NM OF THE COAST OF COLOMBIA BETWEEN 7W
AND 76W. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE OVER
THE SOUTHWESTERN CARIBBEAN. CONVECTION WILL INCREASE OVER THE
WEST-CENTRAL CARIBBEAN AS THE TROPICAL WAVE MOVES ACROSS THAT
PORTION OF THE BASIN.

...HISPANIOLA...

MIDDLE TO UPPER LEVEL MOISTURE IS BEING DRAWN ACROSS THE ISLAND
IN MODERATE SOUTHWESTERLY FLOW ALOFT. A WESTWARD MOVING TROPICAL
WAVE HAS IS PASSING TO THE SOUTH OF THE ISLAND. THESE CONDITIONS
WILL SUPPORT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
THROUGH SUNDAY.

ATLANTIC OCEAN...

A BROAD QUASI-STATIONARY MIDDLE TO UPPER LEVEL LOW IS CENTERED
OVER THE SW NORTH ATLC NEAR 31N65W THAT SUPPORTS A 1016 MB LOW
CENTERED NEAR 27N69W WITH SURFACE TROUGH EXTENDING NE FROM THE
LOW TO 29N68W AND SW FROM THE LOW TO 24N71W. ISOLATED SHOWERS
AND THUNDERSTORMS ARE OCCURRING WITHIN 60 NM OF THE LOW CENTER.
SCATTERED MODERATE CONVECTION WAS NOTED OVER THE ATLANTIC FROM
18N TO 21N BETWEEN 58W AND 64W. A TRIO OF 1031 MB HIGH CENTERS
WELL NORTH OF THE AREA FROM 36N TO 40N BETWEEN 40W AND 55W
DOMINATES THE REMAINDER OF THE SUBTROPICAL NORTHERN ATLC WITH
GENERALLY FAIR WEATHER. EXPECT CONVECTION ASSOCIATED WITH THE
UPPER LOW AND SURFACE LOW TO GRADUALLY WEAKEN OVER THE NEXT 24
HOURS AS THESE FEATURES DISSIPATE.

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

$$
COBB


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