[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU SEP 04 2014

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
2345 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE ASSOCIATED WITH A 1009 MB LOW PRESSURE CENTER IS
ABOUT 200 NM EAST OF THE CAPE VERDE ISLANDS. ITS AXIS EXTENDS
FROM 18N18W TO THE LOW NEAR 13N20W TO 8N20W...MOVING WEST AT 10-
15 KT. METEOSAT SAHARAN AIR LAYER TRACKING IMAGERY AS WELL AS
SSMI TOTAL PRECIPITABLE WATER VAPOR IMAGERY SHOW DRY AIR
ENGULFING THE SYSTEM. A CLUSTER OF MODERATE/ISOLATED STRONG
CONVECTION AND TSTMS IS FROM 12N-15N BETWEEN 20W-
23W...COINCIDING WITH A REGION OF DEEP LAYER HIGH MOISTURE.

A TROPICAL WAVE IS ON THE CENTRAL ATLANTIC WITH AXIS EXTENDING
FROM 17N44W TO 9N45W...MOVING W AT 20 KT. MODERATE LOW-LEVEL
MOISTURE IS ASSOCIATED WITH THE WAVE WITH SOME SAHARAN DRY AIR
AFFECTING ITS NORTHERN ENVIRONMENT. STRONG DEEP LAYER
ENVIRONMENTAL WIND SHEAR IN ITS REGION IS HINDERING CONVECTIVE
ACTIVITY.

A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS
EXTENDING FROM 21N63W TO 11N64W...MOVING W AT 15-20 KT. MAINLY
MODERATE LOW-LEVEL MOISTURE IS ASSOCIATED WITH THE WAVE WHICH
ALONG UPPER-LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE
CONVECTION ACROSS THE NE CARIBBEAN AND TSTMS NE OF PUERTO RICO
FROM 18N-22N BETWEEN 61W-65W.

A TROPICAL WAVE IS ON THE CENTRAL CARIBBEAN WITH AXIS EXTENDING
FROM 21N73W TO 11N74W...MOVING W AT 10 KT. SSMI TOTAL
PRECIPITABLE WATER VAPOR IMAGERY SHOW MODERATE/HIGH MOISTURE IN
ITS SOUTHERN ENVIRONMENT S OF 15N WITH A SLOT OF DRIER AIR
NORTHWARD. STRONG DEEP LAYER ENVIRONMENTAL SHEAR IN THE REGION
IS INHIBITING THE DEVELOPMENT OF CONVECTION NEARBY THE WAVE
AXIS. ISOLATED SHOWERS ARE POSSIBLE IN THE WINDWARD PASSAGE.

A TROPICAL WAVE MOVED INLAND THE YUCATAN PENINSULA AND NORTHERN
CENTRAL AMERICA EARLIER THIS EVENING. ITS AXIS EXTENDS FROM
21N88W TO 13N88W...MOVING W AT 10-15 KT. SCATTERED MODERATE
CONVECTION AND TSTMS  ARE OVER NORTHERN AND CENTRAL YUCATAN
PENINSULA AND THE YUCATAN CHANNEL.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
7N22W TO 8N31W. THE ITCZ EXTENDS FROM 8N31W TO 9N46W TO THE
COAST OF VENEZUELA NEAR 8N60W. BESIDES THE CONVECTION MENTIONED
IN THE TROPICAL WAVE SECTION...SCATTERED MODERATE CONVECTION IS
FROM 6N-9N WEST OF 48W.

...DISCUSSION...

GULF OF MEXICO...

OVER THE WESTERN BASIN...THE REMNANTS OF DOLLY CONTINUE
ENHANCING RAINSHOWERS AND TSTMS ALONG THE MEXICO/TX COAST WEST
OF 95W. A MIDDLE-LEVEL INVERTED TROUGH IS ON THE EASTERN GULF
SUPPORTING A TROPICAL WAVE THAT IS MOVING ACROSS THE YUCATAN
PENINSULA AND NORTHERN CENTRAL AMERICA. SEE TROPICAL WAVES
SECTION FOR MORE DETAILS. THE TROUGH ALOFT ALSO SUPPORT A
SURFACE TROUGH WITH AXIS EXTENDING ACROSS NORTHERN-CENTRAL
FLORIDA TO 27N82W TO 25N83W IN THE SE GULF. A DIFFLUENT
ENVIRONMENT ACROSS THE FLORIDA PENINSULA BEING GENERATED BY AN
UPPER-LEVEL RIDGE CENTERED OVER SOUTH CAROLINA AND A LOW LOCATED
ON THE NW CARIBBEAN IS ENHANCING SCATTERED SHOWERS AND TSTMS
ALONG THE WESTERN PENINSULA AND SE GULF S OF 26N E OF 84W.  WEAK
SURFACE RIDGING PREVAILS ACROSS THE GULF...THUS PROVIDING E-SE
WIND FLOW OF 5-10 KT. THE TROPICAL WAVE WILL ENTER THE BAY OF
CAMPECHE FRIDAY THROUGH SATURDAY THEN WILL MOVE INLAND MEXICO.
NO MAJOR CHANGES ELSEWHERE.

CARIBBEAN SEA...

TWO TROPICAL WAVES ARE ON THE REGION...ONE OVER THE EASTERN
CARIBBEAN AND ANOTHER MOVING ACROSS THE WINDWARD PASSAGE AND
CENTRAL BASIN. THE LATTER CONTINUES TO ENHANCE SCATTERED
MODERATE CONVECTION ACROSS CENTRAL-SOUTHERN HISPANIOLA AND TSTMS
OVER CENTRAL AND SOUTHERN HAITI. SEE THE TROPICAL WAVES SECTION
ABOVE FOR MORE DETAILS. MODERATE MOISTURE OVER WESTERN CUBA AS
WELL AS A DIFFLUENT ENVIRONMENT BEING GENERATED BY AN UPPER-
LEVEL RIDGE CENTERED OVER SOUTH CAROLINA AND A LOW LOCATED ON
THE NW CARIBBEAN SUPPORT SCATTERED HEAVY SHOWERS AND TSTMS ON
THIS REGION OF THE ISLAND AS WELL AS ADJACENT WATERS. IN THE SW
BASIN...DEEP LAYER MOISTURE ALONG WITH A DIFFLUENT ENVIRONMENT
GENERATED BY AN UPPER-LEVEL RIDGE ON THE CENTRAL CARIBBEAN
SUPPORT HEAVY SHOWERS AND TSTMS S OF 16N WEST OF 77W. TRADES OF
15 KT ABOUNDS ACROSS THE BASIN...EXCEPT ON THE CENTRAL CARIBBEAN
WHERE WINDS INCREASE TO 20-25 KT DUE TO A TIGHTER PRESSURE
GRADIENT AND THE PASSAGE OF THE TROPICAL WAVE. SHOWERS WILL
CONTINUE IN THE SW BASIN...EXTENDING TO THE NW BASIN THROUGH
SATURDAY NIGHT. A NEW TROPICAL WAVE WILL MOVE ACROSS THE LESSER
ANTILLES SUNDAY MORNING.

...HISPANIOLA...

THE PASSAGE OF A TROPICAL WAVE CONTINUE TO ENHANCE SCATTERED
MODERATE CONVECTION ACROSS CENTRAL-SOUTHERN HISPANIOLA AND TSTMS
OVER CENTRAL AND SOUTHERN HAITI. SEE THE TROPICAL WAVES SECTION
ABOVE FOR MORE DETAILS. MOISTURE ASSOCIATED WITH THE NEXT TROPICAL
WAVE TO MOVE ACROSS THE ISLAND WILL SUPPORT THE CONTINUATION OF
SHOWERS THROUGH FRIDAY.

ATLANTIC OCEAN...

A MIDDLE-LEVEL INVERTED TROUGH ACROSS THE EASTERN GULF OF MEXICO
AND THE FLORIDA PENINSULA SUPPORT A SURFACE TROUGH WHICH AXIS
REACHES THE SW N ATLC. THIS SURFACE TROUGH IS ENHANCING
SCATTERED SHOWERS WEST OF 75W. A SURFACE RIDGE DOMINATES
ELSEWHERE IN THIS REGION OF THE BASIN BEING ANCHORED BY A 1023
MB HIGH NEAR 32N67W. FARTHER EAST...A BROAD MIDDLE TO UPPER
LEVEL TROUGH SUPPORT A SURFACE TROUGH ALONG 29N37W SW TO 25N47W
WHICH IS ENHANCING SCATTERED SHOWERS AND TSTMS FROM 25N-31N
BETWEEN 36W-42W. SEE TROPICAL WAVES SECTION FOR AREAS OF CONVECTION
OVER PORTIONS OF THE REMAINDER BASIN.

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

$$
NR


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