[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211015
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUN 21 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.

...SPECIAL FEATURES...

A TIGHT PRESSURE GRADIENT BETWEEN STRONG HIGH PRES N OF THE AREA
AND LOW PRESSURE OVER THE SW CARIBBEAN ASSOCIATED WITH A
TROPICAL WAVE AND A LOW OVER NORTHERN COLOMBIA IS SUPPORTING
PULSES OF GALE FORCE WINDS ALONG THE COAST OF COLOMBIA AND IN
THE GULF OF VENEZUELA...EXPECTED TO CONTINUE 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...

A TROPICAL WAVE IS OVER THE EAST TROPICAL ATLC WITH AXIS
APPROXIMATELY LOCATED AT 18W MOVING W AT 10 KT. SSMI TPW IMAGERY
INDICATE THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT
WHILE METEOSAT IMAGERY SHOW SAHARAN DUST AND DRY AIR ENGULFING
THE NORTHERN REGION OF IT. SCATTERED MODERATE CONVECTION AND
ISOLATED TSTMS ARE FROM 08N TO 12N E OF 20W.

A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC WITH AXIS NEAR
39W MOVING W AT 15 KT OVER THE PAST 24 HOURS. SSMI TPW IMAGERY
SHOW THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT EXCEPT
IN THE NORTHERN REGION WHERE METEOSAT SATELLITE IMAGERY DEPICT
SAHARAN DRY AIR AND DUST. NO CONVECTION IS ASSOCIATED WITH THE
WAVE AT THIS TIME.

A TROPICAL WAVE IS IN THE WESTERN TROPICAL ATLC WITH AXIS ALONG
55W MOVING W AT APPROXIMATELY 15 KT OVER THE PAST 24 HOURS. SSMI
TPW IMAGERY SHOWS THE WAVE IS MAINLY EMBEDDED WITHIN A MODERATE
MOIST ENVIRONMENT EXCEPT FROM 09N TO 13N BETWEEN 47W AND 55W
WHERE ABUNDANT MOISTURE SUPPORTS SCATTERED MODERATE CONVECTION.

A TROPICAL WAVE IS IN THE SW CARIBBEAN BASIN WITH AXIS ALONG 81W
FROM 17N TO CENTRAL PANAMA MOVING W NEAR 10 KT OVER THE PAST 24
HOURS. THE SSMI TPW IMAGERY SHOWS THE WAVE IS MAINLY EMBEDDED
WITHIN AN AREA OF RELATIVELY DRY AIR THAT IS HINDERING DEEP
CONVECTION N OF 12N. SCATTERED MODERATE CONVECTION IS IN THE
SOUTHERN WAVE ENVIRONMENT S OF 12N W OF 80W...INCLUDING COSTA
RICA. ISOLATED SHOWERS ARE E OF THE WAVE AXIS S OF 13N.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO 18N15W...THEN
RESUMES W OF A TROPICAL WAVE NEAR 07N20W AND CONTINUES TO
07N33W. THE ITCZ BEGINS NEAR 05N41W AND CONTINUES TO E OF A
TROPICAL WAVE NEAR 05N52W. BESIDES THE CONVECTION ASSOCIATED
WITH THE TROPICAL WAVES...ISOLATED MODERATE CONVECTION IS WITHIN
75 NM EITHER SIDE OF THE MONSOON TROUGH BETWEEN 20W AND 32W.

...DISCUSSION...

THE GULF OF MEXICO...

AN UPPER LOW REMAINS ANCHORED OVER THE NW YUCATAN PENINSULA
ENHANCING A FEW SHOWERS OFF THE NORTHERN COAST OF YUCATAN INTO
THE CENTRAL GULF. ISOLATED SHOWERS AND TSTMS ARE OVER THE SE
GULF FROM 24N TO 26N E OF 84W BEING SUPPORTED BY MOISTURE INFLOW
FROM THE CARIBBEAN AND MIDDLE LEVEL DIFFLUENCE. ISOLATED SHOWERS
AND TSTMS ARE ALSO OFF THE E COAST OF MEXICO FROM 19N TO 24N W
OF 95W. OTHERWISE GENERALLY FAIR SKIES PREVAIL ACROSS THE GULF
DUE TO THE SUBSIDENCE AROUND THE UPPER LOW. SCATTEROMETER DATA
INDICATE E TO SE WINDS OF 10 TO 15 KT ARE OVER THE SE GULF AND
AHEAD OF A SURFACE TROUGH OVER THE BAY OF CAMPECHE FROM 22N90W
TO 17N93W. VARIABLE WINDS OF 5 KT CONTINUE TO DOMINATE THE NE
BASIN AROUND HIGH PRES CENTERED NEAR 27N85W. NO MAJOR CHANGES
ARE EXPECTED IN THE WEATHER PATTERN OVER THE NEXT SEVERAL DAYS.

THE CARIBBEAN SEA...

A TIGHT PRESSURE GRADIENT BETWEEN STRONG HIGH PRES N OF THE AREA
AND LOW PRESSURE OVER THE SW CARIBBEAN ASSOCIATED WITH A
TROPICAL WAVE ALONG 81W AND A LOW OVER NORTHERN COLOMBIA IS
SUPPORTING PULSES OF GALE FORCE WINDS ALONG THE COAST OF
COLOMBIA AND IN THE GULF OF VENEZUELA...EXPECTED TO CONTINUE
OVER THE NEXT COUPLE OF DAYS. SEE THE SPECIAL FEATURES AND
TROPICAL WAVES SECTIONS FOR MORE DETAILS. A DIFFLUENT
ENVIRONMENT BETWEEN AN UPPER LOW CENTERED OVER THE NW YUCATAN
PENINSULA AND A RIDGE COVERING PORTIONS OF THE NW AND SW
CARIBBEAN ALONG WITH SHALLOW MOISTURE SUPPORT SCATTERED SHOWERS
AND TSTMS WITHIN 60 NM OFF THE SW COAST OF CUBA. A SECOND UPPER
LOW IS CENTERED NE OF THE LEEWARD ISLANDS...HOWEVER WITH DRY AIR
AROUND IT...THUS HINDERING THE DEVELOPMENT OF CONVECTION.
OTHERWISE...SAHARAN DRY AIR AND DUST CONTINUES TO SUPPORT HAZY
CONDITIONS ACROSS THE EASTERN BASIN...INCLUDING THE LESSER
ANTILLES. THE NEXT TROPICAL WAVE ENTERS THE EASTERN CARIBBEAN
TUESDAY MORNING.

...HISPANIOLA...

MAINLY DRY AIR IS ACROSS HISPANIOLA THIS MORNING FAVORING CLEAR
SKIES AND FAIR WEATHER. SHALLOW MOISTURE SURROUNDS THE WESTERN
HALF OF THE ISLAND...ENHANCING ISOLATED SHOWERS AND TSTMS ON THE
WINDWARD PASSAGE. EXCEPT FOR THE TYPICAL AFTERNOON
SHOWERS...FAIR WEATHER IS EXPECTED THROUGH MONDAY EVENING WHEN A
MOIST AIRMASS APPROACHES THE ISLAND INCREASING THE PROBABILITIES
OF SHOWERS.

THE ATLANTIC OCEAN...

BROAD SURFACE RIDGING COVERS THE ATLC BEING ANCHORED BY A 1025
MB HIGH NEAR 30N37W. METEOSAT SATELLITE IMAGERY INDICATE SAHARAN
DRY AIR AND DUST COVERING MOST OF THE TROPICS S OF 20N...THUS
LIMITING SHOWER ACTIVITY. FOR INFORMATION ON TROPICAL WAVES SEE
SECTION ABOVE. SURFACE RIDGING WILL BE THE DOMINANT FEATURE THE
NEXT THREE DAYS.

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

$$
NR
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