[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210016
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUN 20 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
0000 UTC.

...SPECIAL FEATURES...

STRONG HIGH PRES N OF THE AREA BUILDING IN THE WAKE OF A TROPICAL
WAVE MOVING INTO THE SW CARIBBEAN IS SUPPORTING PULSES OF GALE
FORCE WINDS COAST OF COLOMBIA AND IN THE GULF OF VENEZUELA OVER
THE NEXT COUPLE OF DAYS. WINDS TO GALE FORCE CAN BE EXPECTED
PRIMARILY AT NIGHT AND IN THE EARLY MORNING HOURS...BUT STRONG
TO NEAR GALE FORCE WINDS WILL PERSIST THROUGHOUT THE DAY AND
NIGHT ACROSS MUCH OF THE CENTRAL CARIBBEAN INTO SUNDAY. THE
WINDS WILL DIMINISH SLIGHTLY MONDAY AS THE NEXT TROPICAL WAVE
MOVES INTO THE AREA...BUT INCREASE AGAIN BY MID WEEK. PLEASE
READ THE HIGH SEAS FORECAST... MIAHSFAT2/FZNT02 KNHC...AND THE
OFFSHORE FORECAST...MIAOFFNT3/ FZNT23 KNHC...FOR MORE DETAILS.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 34W FROM 11N SOUTHWARD
MOVING WESTWARD 10 TO 15 KT. THE TOTAL PRECIPITABLE WATER
IMAGERY SHOWS THAT THE CENTRAL AND SOUTHERN WAVE ENVIRONMENT
CONTINUES IS EMBEDDED WITHIN A MODERATE TO HIGH SURGE OF
MOISTURE. METEOSAT SATELLITE IMAGERY DEPICTS SAHARAN DRY AIR AND
DUST IN THE NORTHERN WAVE ENVIRONMENT. ITCZ-RELATED CONVECTIVE
PRECIPITATION IS NEAR THE TROPICAL WAVE.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 51W FROM 13N SOUTHWARD.
IT HAS BEEN MOVING WESTWARD 15 KT DURING THE LAST 24 HOURS. THE
TOTAL PRECIPITABLE WATER IMAGERY SHOWS THAT THE WAVE IS MAINLY
EMBEDDED WITHIN A MODERATE SURGE OF MOISTURE. CONVECTIVE
PRECIPITATION...ISOLATED TO WIDELY SCATTERED MODERATE FROM 10N
TO 13N BETWEEN 45W AND 51W.

A CARIBBEAN SEA TROPICAL WAVE NEAR 80W FROM SOUTHWESTERN JAMAICA
TO PANAMA...MOVING WESTWARD 10 TO 15 KT. THE TOTAL PRECIPITABLE
WATER IMAGERY SHOWS THAT THE WAVE MAINLY IS  EMBEDDED WITHIN AN
AREA OF RELATIVELY DRY AIR. CONVECTIVE PRECIPITATION...WIDELY
SCATTERED MODERATE TO ISOLATED STRONG IS IN THE COASTAL WATERS
OF COSTA RICA AND EXTREME SOUTHEASTERN NICARAGUA.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF GUINEA
NEAR 10N14W TO 08N25W 08N30W. THE ITCZ CONTINUES FROM 08N35W TO
07N50W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE CONVECTION
IS NOTED WITHIN 60 NM EITHER SIDE OF THE MONSOON TROUGH AND
WITHIN 120 NM EITHER SIDE OF THE ITCZ BETWEEN 35W AND 45W.

...DISCUSSION...

THE GULF OF MEXICO...

AN UPPER LOW REMAINS ANCHORED OVER THE NW POINT OF THE YUCATAN
PENINSULA THIS EVENING...ENHANCING A FEW SHOWERS OFF THE
NORTHERN COAST OF YUCATAN INTO THE CENTRAL GULF. HIGH LEVEL
CLOUDINESS IS NOTED OVER THE EAST CENTRAL GULF AND STRAITS OF
FLORIDA RELATED TO THUNDERSTORMS OVER THE FLORIDA PENINSULA AND
WESTERN CUBA RESPECTIVELY. OTHERWISE GENERALLY FAIR SKIES
PREVAIL ACROSS THE GULF DUE TO THE SUBSIDENCE AROUND THE UPPER
LOW. SCATTEROMETER DATA FROM EARLIER IN THE DAY INDICATED
MODERATE TO FRESH SE WINDS OFF THE WESTERN COAST OF THE YUCATAN
PENINSULA...BETWEEN HIGH PRES CENTERED OVER THE NE GULF AND A
TROPICAL WAVE FARTHER SOUTH MOVING THROUGH GUATEMALA TOWARD
SOUTHERN MEXICO. ELSEWHERE LIGHT TO GENTLE BREEZES PREVAIL
ACROSS THE GULF WITH 2 TO 4 FT SEAS. NO MAJOR CHANGES ARE
EXPECTED IN THE WEATHER PATTERN OVER THE NEXT SEVERAL DAYS.

THE CARIBBEAN SEA...

HIGH PRES BUILDING IN THE WAKE OF THE TROPICAL WAVE MOVING INTO
THE SW CARIBBEAN IS SUPPORTING CONTINUAL STRONG TO NEAR GALE
FORCE WINDS OVER MAINLY THE S CENTRAL CARIBBEAN...PULSING TO
GALE FORCE AT NIGHT OFF COLOMBIA AND OCCASIONALLY IN THE GULF
VENEZUELA. RECENT SCATTEROMETER DATA INDICATE THESE WINDS ARE 30
KT OFF COLOMBIA...BUT ARE LIKELY TO INCREASE TO GALE FORCE LATE
THIS EVENING. THESE WINDS WILL DIMINISH SLIGHTLY MON AS THE NEXT
TROPICAL WAVE MOVES THROUGH THE CENTRAL CARIBBEAN.

AN UPPER LOW CENTERED OVER THE YUCATAN PENINSULA IS SUPPORTING
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS THE NW
CARIBBEAN AND WESTERN CUBA. NORTHERLY FLOW ON THE WEST SIDE OF A
SECOND UPPER LOW CENTERED OVER THE LEEWARD ISLANDS IS SHEARING
THE TOPS OF THE AFTERNOON CONVECTION TRYING TO FORM OVER THE
HIGHER ELEVATIONS OF PUERTO RICO...HISPANIOLA AND EASTERN CUBA.
TRADE WIND CONVERGENCE IS RESPONSIBLE FOR GENERATING A FEW
SHOWERS OFF COSTA RICA AND WESTERN PANAMA. OTHERWISE FAIR SKIES
ARE NOTED ACROSS THE BASIN EXCEPT FOR A FEW HIGH CLOUDS ARE
NOTED OVER THE SW AND S CENTRAL CARIBBEAN...THE UPPER OUTFLOW OF
CONVECTION OVER THE TROPICAL EASTERN PACIFIC.

...HISPANIOLA...

SCATTERED THUNDERSTORMS FORMED ALONG THE NORTHERN AND CENTRAL
MOUNTAIN RANGES OF THE DOMINICAN REPUBLIC AND THE TIBURON
PENINSULA OF SOUTHERN HAITI EARLIER THIS AFTERNOON DUE TO
DAYTIME HEATING. NORTHERLY FLOW ALOFT ON THE WEST SIDE OF AN
UPPER LOW OVER THE LEEWARD ISLANDS KEPT THIS ACTIVITY SHORT
LIVED. THIS PATTERN WILL LIKELY REPEAT SUNDAY INTO EARLY NEXT
WEEK. CONVECTION MAY BE LONGER LASTING WITH THE POTENTIAL FOR
LOCALIZED HEAVY RAINFALL MONDAY AND TUESDAY HOWEVER AS THE UPPER
LOW DRIFTS WESTWARD...EVENTUALLY DIRECTLY OVER THE ISLAND BY
EARLY TUE.

THE ATLANTIC OCEAN...

W OF 60W...THE SUBTROPICAL RIDGE EXTENDS EAST TO WEST ALONG
ROUGHLY 29N/30N...MAINTAINING GENERALLY LIGHT TO GENTLE BREEZES
NORTH OF 22N...WITH MODERATE TO OCCASIONALLY FRESH TRADE WINDS S
OF 22N. A FEW SHOWERS ARE NOTED NE OF THE BAHAMAS BETWEEN AN
UPPER RIDGE CENTERED NEAR BERMUDA AND AN UPPER LOW OVER THE
LEEWARD ISLANDS. A FEW AFTERNOON SHOWERS WERE ACTIVE ACROSS THE
ISLANDS OF THE BAHAMAS AND CAY SAL BUT HAVE SINCE DISSIPATED. NO
MAJOR CHANGES IN THE PATTERN FOR THE NEXT SEVERAL DAYS.

FOR THE CENTRAL ATLC...AN UPPER LOW IS CENTERED OVER THE LEEWARD
ISLANDS...THE SW PORTION OF A BIGGER TUTT THAT REACHES NE TOWARD
THE AZORES. THE UPPER TROUGHING IS INTERACTING WITH A TROPICAL
WAVE BETWEEN 50W AND 55W S OF 15N TO ENHANCE A FEW SHOWERS AND
THUNDERSTORMS NEAR 12N50W. A BROAD SUBTROPICAL RIDGE ANCHORED BY
SURFACE HIGH PRES CENTERED NEAR 31N45W MAINTAINING GENTLE BREEZES
N OF 20N. MODERATE TO FRESH TRADE WINDS ARE NOTED S OF 20N
BETWEEN THE RIDGE TO THE NORTH AND THE PAIR OF TROPICAL WAVES
MIGRATING WESTWARD THROUGH THE DEEP TROPICS. TRADE WIND
CONVERGENCE IS SUPPORTING AREAS OF MAINLY SHOWERS S OF 13N
BETWEEN 35W AND 45W.

IN THE EASTERN ATLC...ANOTHER PLUME OF SAHARAN DUST IS EMERGING
OFF THE COAST OF NORTH AFRICA. THE DRY PATTERN IS KEEPING THE
REGION MAINLY CLOUD FREE N OF 10N...WITH ONLY A FEW SHOWERS
NOTED FARTHER SOUTH ALONG THE MONSOON TROUGH/ITCZ. THIS MAY
CHANGE SLIGHTLY OVER THE NEXT 24 HOURS AHEAD OF THE NEXT
TROPICAL WAVE EMERGING OFF THE COAST OF AFRICA.

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

$$
CHRISTENSEN
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