[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE E ATLC ASSOCIATED WITH A 1012 MB LOW NEAR
11N18W AT 0300 UTC. 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 MODERATE CONVECTION AND
ISOLATED TSTMS FROM 08N TO 13N BETWEEN 19W AND 25W AND ISOLATED
SHOWERS AND TSTMS ELSEWHERE E OF 19W.

A TROPICAL WAVE IS IN THE CENTRAL ATLC WITH AXIS NEAR 38W
...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 VERY DRY ENVIRONMENT...WHICH IS KEEPING THE
WAVE DEVOID OF CONVECTION.

A TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES. ITS AXIS
IS NEAR 61W 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 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 89W 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. LOW LEVEL
MOISTURE CONVERGENCE AND DIVERGENCE ALOFT SUPPORT SCATTERED TO
ISOLATED SHOWERS AND TSTMS OVER THE NW CARIBBEAN W OF 82W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 09N18W TO 08N28W WHERE THE ITCZ
CONTINUES TO 07N42W TO 07N50W TO GUYANA COASTLINE NEAR 08N59W.
OTHER THAN THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE NEAR
THE CAPE VERDE ISLANDS...SCATTERED MODERATE CONVECTION IS FROM
05N TO 10N BETWEEN 38W AND 43W. ISOLATED SHOWERS ARE WITHIN 75
NM EITHER SIDE OF THE ITCZ W OF 43W.

...DISCUSSION...

...GULF OF MEXICO...

A STATIONARY FRONT PREVAILS ACROSS NORTHERN FLORIDA...THEN WEST
ALONG THE NORTHERN GULF COASTLINE TO SE TEXAS BEING SUPPORTED BY
A MIDDLE TO UPPER LEVEL TROUGH OVER THE E CONUS AND FAR W-NW
ATLC. AN INVERTED TROUGH ALOFT OVER THE E GULF SUPPORT A SURFACE
TROUGH FROM 28N82W SW TO 24N87W TO 22N93W. LOW LEVEL MOISTURE
INFLOW FROM THE CARIBBEAN INTO THE GULF SUPPORT ISOLATED SHOWERS
OVER THE CENTRAL AND NE BASIN BETWEEN THE TROUGH AND THE FRONT.
SCATTERED SHOWERS AND TSTMS ARE OVER THE SE GULF AHEAD OF THE
TROUGH COINCIDING WITH DIVERGENT FLOW ALOFT. VARIABLE WINDS OF
LESS THAN 15 KT ARE BASIN-WIDE. THE STATIONARY FRONT WILL
DISSIPATE SATURDAY LEAVING A TROUGH OF LOW PRESSURE ALONG THE
NORTHERN GULF WITH A LOW PRESSURE CENTER DEVELOPING OVER THE NW
BASIN.

CARIBBEAN SEA...

A TROPICAL WAVE IS MOVING ACROSS THE YUCATAN
PENINSULA...GUATEMALA TO EPAC WATERS. THE WAVE IS ASSOCIATED
WITH SHALLOW MOISTURE...WHICH ALONG WITH DIVERGENCE ALOFT
SUPPORT SCATTERED TO ISOLATED SHOWERS AND TSTMS OVER THE NW
CARIBBEAN W OF 82W. A SECOND TROPICAL WAVE MOVES ACROSS THE LESSER
ANTILLES WITH AXIS NEAR 61W. 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 LOW OVER THE NW
CARIBBEAN AND A BROAD RIDGE ACROSS THE REMAINDER BASIN SUPPORT
ISOLATED SHOWERS AND TSTMS BETWEEN CUBA AND JAMAICA AND ACROSS
THE WINDWARD PASSAGE. LOW PRESSURE OVER NW COLOMBIA ENHANCES
SCATTERED MODERATE CONVECTION S OF 11N E OF 81W. NE TO E WINDS
OF 20 TO 25 KT ARE FROM 11N TO 14N BETWEEN 70W 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 LOW OVER THE NW CARIBBEAN AND A
BROAD RIDGE ACROSS THE REMAINDER BASIN SUPPORT SCATTERED TO
ISOLATED SHOWERS AND TSTMS IN THE WINDWARD PASSAGE AND ACROSS
THE ISLAND. SHOWERS ARE FORECAST TO CEASE BY SATURDAY AFTERNOON.
HOWEVER...THE PASSAGE OF A TROPICAL WAVE DURING SUNDAY AND MONDAY
WILL BRING SHOWERS FORECAST TO PERSIST THROUGH EARLY TUESDAY
MORNING.

ATLANTIC OCEAN...

A STATIONARY FRONT PREVAILS ACROSS THE SW N ATLC FROM 30N76W TO
JACKSONVILLE NEAR 30N81W...ACROSS NORTHERN FLORIDA...THEN WEST
ALONG THE NORTHERN GULF COASTLINE TO SE TEXAS. THIS FRONT IS
BEING SUPPORTED BY A MIDDLE TO UPPER LEVEL TROUGH OVER THE E
CONUS AND FAR W-NW ATLC. ISOLATED SHOWERS AND TSTMS ARE WITHIN
100 NM AHEAD OF THE FRONT. SIMILAR SHOWER ACTIVITY IS BETWEEN
NORTHERN CUBA AND HISPANIOLA AND THE CENTRAL AND SOUTHERN
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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