Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 311048
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN MAY 31 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...
TROPICAL WAVE EXTENDS FROM 02N41W TO 10N38W MOVING W AT 15-20
KT. THE WAVE REMAINS LARGELY EMBEDDED WITHIN THE ITCZ AXIS AND
COINCIDES WITH VERY SUBTLE GLOBAL MODEL INDICATED 700 MB
TROUGHING BETWEEN 32W-47W. NO SIGNIFICANT CONVECTION IS
ASSOCIATED WITH WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 08N75W TO 17N75W 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
CARIBBEAN SEA IS PRODUCING SOUTHWESTERLY SHEAR OVER 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
07N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N19W TO 05N25W TO 06N29W TO 03N41W TO 04N48W TO 02N51W.
SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 03N-
06N BETWEEN THE PRIME MERIDIAN AND 05W...AND FROM 02N-20N
BETWEEN 18W-23W. SCATTERED MODERATE CONVECTION IS FROM 04N-07N
BETWEEN 25W-34W...AND FROM 02N-07N BETWEEN 42W-55W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE WAS NOTED OVER THE GULF ALONG 91W. WEST-
NORTHWESTERLY FLOW ALOFT WAS INDICATED OVER MUCH OF THE BASIN
BETWEEN THE RIDGE AND A DOWNSTREAM BROAD UPPER LEVEL TROUGH
EXTENDING FROM THE SOUTHEASTERN FLORIDA PENINSULA SOUTHWARD OVER
THE WESTERN CARIBBEAN ALONG 78W. A SHARP UPPER TROUGH IS ALSO
OVER THE CENTRAL AND SOUTHERN U.S. PLAINS THAT CONTINUES TO
EJECT SHORTWAVE ENERGY AROUND THE BASE OF THE TROUGH OVER
EASTERN TEXAS AND THE SOUTHERN MISSISSIPPI RIVER VALLEY REGION.
CONVECTION ASSOCIATED WITH A STATIONARY FRONT ACROSS THIS AREA
IS OCCURRING GENERALLY NW OF A LINE FROM 30N93W TO THE MEXICO
COAST NEAR 23N98W. FARTHER EAST...A WEAK SURFACE TROUGH IS
ANALYZED ALONG THE WESTERN COAST OF THE FLORIDA PENINSULA
DIURNALLY DRIVEN BY DAYTIME HEATING. PREVIOUS TSTM ACTIVITY HAS
ALL BUT DIMINISHED THIS MORNING WITH ONLY A FEW ISOLATED SHOWERS
REMAINING OCCURRING WITHIN 30 NM EITHER SIDE OF THE BOUNDARY
FROM THE MIDDLE FLORIDA KEYS TO THE FLORIDA BIG BEND REGION.
ELSEWHERE...GENTLE TO MODERATE BREEZE ANTICYCLONIC WINDS ARE
NOTED ACROSS THE GULF THIS MORNING ON THE SOUTHWESTERN PERIPHERY
OF A RIDGE ANCHORED ACROSS THE SE CONUS. THE UPPER LEVEL TROUGH
OVER THE PLAINS WILL CONTINUE TO DIG SOUTHEASTWARD WHICH WILL
RESULT IN INCREASED CHANCE FOR CONVECTION ACROSS THE NW 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 78W/79W. WEAK UPPER LEVEL
DIFFLUENCE IS SUPPORTING WIDELY SCATTERED SHOWERS AND ISOLATED
TSTMS ACROSS MUCH OF THE BASIN S OF 20N E OF 83W. DEEP MOISTURE
IS ADVECTING EAST OF THE BROAD TROUGH AXIS IN SOUTHWESTERLY FLOW
ALOFT FROM THE SOUTHWESTERN CARIBBEAN...OVER THE CENTRAL AND
EASTERN CARIBBEAN...INTO THE TROPICAL ATLC. A TROPICAL WAVE IS
ACROSS THE WESTERN CARIBBEAN ALONG 75W/76W AND CONTINUES TO
PROVIDE FOCUS FOR PORTIONS OF THE ISOLATED SHOWER ACTIVITY
ACROSS THE CENTRAL AND WESTERN CARIBBEAN. EAST-SOUTHEAST TRADES
ARE EXPECTED TO INCREASE FROM FRESH BREEZE CONDITIONS TO A RANGE
OF FRESH TO STRONG BREEZE CONDITIONS BY MONDAY AS STRONG HIGH
PRESSURE ANCHORED TO THE NORTHEAST OVER THE CENTRAL ATLC CREATES
A STRENGTHENED PRESSURE GRADIENT ACROSS THE CENTRAL CARIBBEAN.

...HISPANIOLA...
MIDDLE TO UPPER LEVEL MOISTURE IS BEING DRAWN OVER THE ISLAND IN
MODERATE SOUTHWESTERLY FLOW ALOFT. A WESTWARD MOVING TROPICAL
WAVE IS PASSING TO THE SOUTHWEST OF THE ISLAND. THESE CONDITIONS
ARE EXPECTED TO SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS
THROUGH SUNDAY.

ATLANTIC OCEAN...
A BROAD QUASI-STATIONARY MIDDLE TO UPPER LEVEL LOW IS CENTERED
OVER THE SW NORTH ATLC NEAR 32N65W THAT SUPPORTS A 1015 MB LOW
CENTERED NEAR 28N70W WITH SURFACE TROUGH EXTENDING N-NE FROM THE
LOW TO 30N69W AND S-SW FROM THE LOW TO 25N72W. ISOLATED SHOWERS
ARE OCCURRING WITHIN 90 NM OF THE LOW CENTER. SCATTERED MODERATE
CONVECTION WAS NOTED OVER THE ATLC FROM 17N-25N BETWEEN 56W-69W
FOCUSED IN THE VICINITY OF A SURFACE TROUGH ANALYZED FROM NE OF
HISPANIOLA NEAR 20N68W TO 23N64W. 1030 MB AND 1031 MB HIGH
CENTERS ARE LOCATED NORTH OF THE DISCUSSION AREA IN THE VICINITY
OF 37N42W THAT DOMINATE THE REMAINDER OF THE SUBTROPICAL 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

$$
HUFFMAN



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