[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151046
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT AUG 15 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
1045 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE E ATLC ASSOCIATED WITH A 1011 MB LOW
NEAR 10N20W. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE
SURFACE TO 850 MB SHOW THE WAVE IS ASSOCIATED WITH A BROAD AREA
OF MODERATE MOISTURE THAT ALONG WITH A DIFFLUENT WIND
ENVIRONMENT ALOFT SUPPORT SCATTERED TO ISOLATED SHOWERS AND
TSTMS FROM 05N TO 13N E OF 24W.

A TROPICAL WAVE IS IN THE CENTRAL ATLC WITH AXIS NEAR 42W
...MOVING W AT 10 KT OVER THE PAST 24 HOURS. CIRA LAYER
PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW THE
WAVE IS WITHIN A DRY ENVIRONMENT...WHICH IS KEEPING THE WAVE
DEVOID OF CONVECTION.

A TROPICAL WAVE ENTERED THE EASTERN CARIBBEAN. ITS AXIS IS NEAR
63W AND HAS BEEN MOVING W AT 15 KT OVER THE PAST 24 HOURS. THE
WAVE IS ASSOCIATED WITH A MODERATE MOIST ENVIRONMENT FROM THE
SURFACE TO 850 MB ACCORDING TO CIRA LAYER PRECIPITABLE WATER
IMAGERY. A DIFFLUENT WIND ENVIRONMENT AT THE UPPER LEVELS IN THE
NE CARIBBEAN AND ADJACENT ATLC WATERS ALONG WITH THE MOISTURE
SUPPORT SCATTERED TO ISOLATED SHOWERS OVER PUERTO RICO...VIRGIN
ISLANDS AND NORTHERN LEEWARD ISLANDS. STRONG DEEP LAYER WIND
SHEAR HINDER CONVECTION ACROSS THE E-SE CARIBBEAN BASIN.

A TROPICAL WAVE EXTENDS FROM THE YUCATAN PENINSULA...ACROSS
GUATEMALA TO EPAC WATERS. ITS AXIS IS NEAR 91W AND HAS BEEN
MOVING AT 5 KT OVER THE LAST 24 HOURS. THE WAVE IS ASSOCIATED
WITH A MODERATE MOIST ENVIRONMENT FROM THE SURFACE TO 850 MB
ACCORDING TO CIRA LAYER PRECIPITABLE WATER IMAGERY. SCATTERED TO
ISOLATED SHOWERS AND TSTMS ARE OVER THE NW CARIBBEAN W OF 81W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 11N15W TO A 1011 MB LOW NEAR
10N20W TO 08N29W WHERE THE ITCZ CONTINUES TO 06N44W TO 08N53W TO
GUYANA COASTLINE NEAR 08N59W. OTHER THAN THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVE NEAR THE CAPE VERDE
ISLANDS...SCATTERED MODERATE CONVECTION IS FROM 06N TO 11N
BETWEEN 37W AND 42W. ISOLATED SHOWERS ARE WITHIN 75 NM EITHER
SIDE OF THE ITCZ W OF 43W.

...DISCUSSION...

...GULF OF MEXICO...

A SURFACE TROUGH EXTENDS ACROSS NORTHERN FLORIDA SW TO 29N90W TO
28N96W WITH ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF ITS
AXIS. A SECOND SURFACE TROUGH IS ANALYZED FROM 27N86W TO 25N90W
TO 22N93W BEING SUPPORTED BY A MIDDLE TO UPPER LEVEL TROUGH OVER
THE EASTERN CONUS WITH BASE EXTENDING INTO THE E GULF. LOW LEVEL
MOISTURE INFLOW FROM THE CARIBBEAN TO THE GULF ALONG WITH A
DIFFLUENT ENVIRONMENT BETWEEN THE BASE OF THE UPPER TROUGH AND
AN UPPER HIGH NEAR 23N85W SUPPORT SCATTERED SHOWERS AND TSTMS
OVER THE SE GULF AHEAD OF THE TROUGH FROM 23N TO 27N E OF 89W.
EASTERLY WIND FLOW OF 15 KT IS OVER THE NE GULF N OF 28N...
VARIABLE WINDS OF LESS THAN 15 KT DOMINATE ELSEWHERE. SURFACE
TROUGHING WILL PREVAIL ACROSS THE NORTHERN GULF THROUGH TONIGHT.
SURFACE RIDGING WILL START TO BUILD ACROSS THE ENTIRE BASIN
SUNDAY.

CARIBBEAN SEA...

A TROPICAL WAVE IS MOVING ALONG THE YUCATAN
PENINSULA...GUATEMALA TO EPAC WATERS. THE WAVE IS ASSOCIATED
WITH SHALLOW MOISTURE THAT ENHANCE ISOLATED SHOWERS AND TSTMS
OVER THE NW CARIBBEAN W OF 84W. A SECOND TROPICAL WAVE ENTERED
THE EASTERN BASIN EARLIER THIS MORNING. THE WAVE IS ASSOCIATED
WITH A MODERATE MOIST ENVIRONMENT AT THE LOWER LEVELS THAT ALONG
WITH A DIFFLUENT WIND ENVIRONMENT AT THE UPPER LEVELS IN THE NE
CARIBBEAN SUPPORT SCATTERED TO ISOLATED SHOWERS OVER PUERTO
RICO...VIRGIN ISLANDS AND NORTHERN LEEWARD ISLANDS. STRONG DEEP
LAYER WIND SHEAR HINDER CONVECTION ACROSS THE CENTRAL AND
REMAINDER E CARIBBEAN BASIN. SEE TROPICAL WAVES SECTION FOR MORE
DETAILS. DIFFLUENCE ALOFT BETWEEN AN UPPER RIDGE OVER THE SW N
ATLC AND A BROAD RIDGE CENTERED OVER THE SE CARIBBEAN SUPPORT
SCATTERED TO ISOLATED SHOWERS ACROSS THE WINDWARD PASSAGE. LOW
PRESSURE OVER NW COLOMBIA ENHANCES SCATTERED MODERATE CONVECTION
AND TSTMS S OF 12N E OF 82W. NE TO E WINDS OF 20 TO 25 KT ARE
FROM 11N TO 14N BETWEEN 71W AND 76W WITH SEAS TO 9 FT. THE WAVE
OVER THE E BASIN WILL MOVE OVER PUERTO RICO SATURDAY ENHANCING
SHOWERS AND OVER THE CENTRAL BASIN SUNDAY THROUGH MONDAY
ENHANCING SHOWERS ACROSS HISPANIOLA.

...HISPANIOLA...

SHALLOW MOISTURE ACROSS THE CARIBBEAN SEA ALONG WITH A DIFFLUENT
REGION ALOFT BETWEEN AN UPPER RIDGE OVER THE SW N ATLC AND A
BROAD RIDGE CENTERED OVER THE SE CARIBBEAN SUPPORT SCATTERED
SHOWERS ACROSS THE WINDWARD PASSAGE AND ISOLATED SHOWERS OVER
THE ISLAND. SHOWERS ARE FORECAST TO CEASE THIS AFTERNOON.
HOWEVER...THE PASSAGE OF A TROPICAL WAVE DURING SUNDAY AND
MONDAY WILL BRING SHOWERS THAT ARE FORECAST TO PERSIST THROUGH
EARLY TUESDAY MORNING.

ATLANTIC OCEAN...

A DISSIPATING STATIONARY FRONT EXTENDS FROM 30N80W TO
JACKSONVILLE WHERE IT TRANSITIONS INTO A SURFACE TROUGH THAT
EXTENDS ACROSS NORTHERN FLORIDA. THE TROUGH IS BEING SUPPORTED
BY A MIDDLE TO UPPER LEVEL TROUGH OVER THE E CONUS AND FAR W-NW
ATLC. ISOLATED SHOWERS AND TSTMS CONTINUE BETWEEN THE SOUTHERN
FLORIDA PENINSULA AND THE NORTHERN-CENTRAL BAHAMAS. A BROAD
SURFACE RIDGE COVERS THE REMAINDER BASIN AND SUPPORTS FAIR
WEATHER. FOR TROPICAL WAVES SEE SECTION ABOVE.

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

$$
NR
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