[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED AUG 28 2013

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS AN AXIS ALONG 19N38W TO A 1012 MB LOW
EMBEDDED IN THE MONSOON TROUGH TO 09N38W AND IS MOVING W NEAR 10
KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A
MODERATE TO HIGH MOIST ENVIRONMENT. ISOLATED MODERATE CONVECTION
IS WITHIN 150 NM OF ITS AXIS.

TROPICAL WAVE EXTENDS AN AXIS ALONG 23N52W TO 16N55W TO A 1015
MB LOW NEAR 11N54W AND IS MOVING W NEAR 15 KT. TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE NORTHERN AND SOUTHERN
PORTIONS OF THE WAVE ARE WITHIN A MODERATE MOIST ENVIRONMENT.
DRIER AIR IS NOTED IN THE CENTRAL PORTION OF THE WAVE WHERE
CONVECTION IS BEING HINDERED. ISOLATED SHOWERS ARE WITHIN 100 NM
EITHER SIDE OF THE WAVE AXIS FROM 19N-22N. SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS ASSOCIATED WITH THE LOW
PRESSURE ARE FROM 10N-13N BETWEEN 52W-55W.

TROPICAL WAVE IS OVER THE FAR WESTERN CARIBBEAN SEA EXTENDING AN
AXIS ALONG 21N86W TO 12N89W AND IS MOVING W NEAR 5 KT. TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS MOVING FROM A
MODERATE MOIST ENVIRONMENT TO A DRIER ENVIRONMENT INLAND IN
CENTRAL AMERICA AND THE YUCATAN PENINSULA. ISOLATED SHOWERS ARE
WITHIN 100 NM EITHER SIDE OF THE WAVE AXIS.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM 12N16W TO 10N28W TO A 1012
MB LOW NEAR 13N38W TO 11N51W. BESIDES THE CONVECTION ASSOCIATED
WITH THE TROPICAL WAVES ALREADY DISCUSSED...SCATTERED MODERATE
CONVECTION AND TSTMS ARE FROM 04N-09N BETWEEN 26W-33W AND FROM
05N-11N BETWEEN 17W-26W. A CLUSTER OF SIMILAR CONVECTION IS FROM
10N-14N E OF 20W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL INVERTED TROUGH EXTENDING FROM CENTRAL TEXAS TO
JUST NORTH OF THE YUCATAN PENINSULA SUPPORTS A SURFACE TROUGH IN
THE WESTERN GULF ALONG 27N96W TO 23N95W 19N93W. SCATTERED
SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE AXIS. IN THE NE
GULF...A MIDDLE LEVEL INVERTED TROUGH EXTENDING ACROSS FLORIDA
TO THE YUCATAN PENINSULA SUPPORTS A WEAK SURFACE TROUGH ALONG
30N83W TO 27N85W. ISOLATED SHOWERS ARE N OF 27N E OF 87W. AN
ELONGATED UPPER LEVEL LOW CENTERED OVER THE FLORIDA KEYS
SUPPORTS A SURFACE TROUGH ALONG 27N79W TO 23N81W WHICH IS
ENHANCING SCATTERED SHOWERS AND TSTMS FROM 24N-27N BETWEEN 79W-
82W. THE UPPER LOW IS ALSO ENHANCING SIMILAR CONVECTION IN THE
SE GULF FROM 23N-24N BETWEEN 84W-86W. FAIR WEATHER IS ACROSS THE
REMAINDER BASIN SUPPORTED BY MIDDLE LEVELS DRY AIR SUBSIDENCE.

THE SURFACE TROUGH OVER THE WESTERN GULF IS EXPECTED TO
DISSIPATE TONIGHT. A TROPICAL WAVE IS EXPECTED TO MOVE OVER THE
BAY OF CAMPECHE EARLY ON THURSDAY GENERATING RAINSHOWERS WHILE A
HIGH PRESSURE DEVELOPS OVER THE NE BASIN. ONCE DEVELOPED...HIGH
PRESSURE OVER THE EASTERN GULF IS EXPECTED TO PERSIST UNTIL
FRIDAY AFTERNOON.

CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE FAR WESTERN CARIBBEAN SEA EXTENDING
AN AXIS ALONG 21N86W TO 12N89W. TOTAL PRECIPITABLE WATER IMAGERY
SHOW THE WAVE IS MOVING FROM A MODERATE MOIST ENVIRONMENT TO A
DRIER ENVIRONMENT INLAND IN CENTRAL AMERICA AND THE YUCATAN
PENINSULA. ISOLATED SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE
WAVE AXIS. A MODERATE TO HIGH MOIST ENVIRONMENT OVER THE WESTERN
BASIN ALONG WITH MIDDLE LEVEL DIFFLUENCE SUPPORTS SCATTERED
MODERATE CONVECTION AND TSTMS FROM 15N-20N BETWEEN 80W-85W.
MIDDLE TO UPPER LEVEL DIFFLUENCE SUPPORTS SIMILAR CONVECTION
OVER THE SOUTHERN BASIN FROM 10N-15N W OF 77W. A SURFACE TROUGH
EXTENDS FROM 25N72W...ALONG EASTERN CUBA TO 15N77W. THIS TROUGH
IS ENHANCING SCATTERED MODERATE CONVECTION AND TSTMS OVER THE
CENTRAL AND EASTERN BAHAMAS AND ISOLATED SHOWERS AND TSTMS OVER
SOUTHERN HAITI AND FROM 15N-18N BETWEEN 73W-77W. AN UPPER LEVEL
TROUGH IS ENHANCING SHOWERS AND TSTMS ACROSS THE WINDWARD
ISLANDS. DRY AIR IN THE LOWER AND MIDDLE LEVELS SUPPORTS FAIR
WEATHER IN THE REMAINDER EASTERN CARIBBEAN.

A TROPICAL WAVE IS EXPECTED TO ENTER THE EASTERN BASIN VERY
EARLY ON THURSDAY AND MOVE ACROSS PUERTO RICO ON FRIDAY.

HISPANIOLA...
MODERATE MOISTURE IS ACROSS THE ISLAND AS DEPICTED IN TOTAL
PRECIPITABLE IMAGERY. A SURFACE TROUGH EXTENDS FROM
25N72W...ALONG EASTERN CUBA TO 15N77W. THIS TROUGH IS ENHANCING
ISOLATED SHOWERS AND TSTMS OVER SOUTHERN HAITI...WESTERN
DOMINICAN REPUBLIC AND THE WINDWARD PASSAGE. SHOWERS MAY
PERSISTS THROUGH EARLY THURSDAY WHEN A DRY AIRMASS IS EXPECTED
TO MOVE ACROSS THE ISLAND. HOWEVER...WEATHER CONDITIONS START TO
DETERIORATE LATE FRIDAY AS A TROPICAL WAVE APPROACHES THE ISLAND.
THE TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE ISLAND
ON SATURDAY.

ATLANTIC OCEAN...
AN ELONGATED UPPER LEVEL LOW CENTERED OVER THE FLORIDA KEYS
SUPPORTS A SURFACE TROUGH ALONG 27N79W TO 23N81W WHICH IS
ENHANCING SCATTERED SHOWERS AND TSTMS FROM 24N-27N BETWEEN 79W-
82W. A SURFACE TROUGH EXTENDS FROM 25N72W...ALONG EASTERN CUBA
TO 15N77W. THIS TROUGH IS ENHANCING SCATTERED MODERATE
CONVECTION AND TSTMS OVER THE CENTRAL AND EASTERN BAHAMAS. A
STATIONARY FRONT ENTERS THE AREA OF DISCUSSION FROM 30N62W TO
28N66W TO 30N70W. THIS FRONTAL BOUNDARY BEING SUPPORTED BY AN
UPPER LEVEL TROUGH IS ENHANCING SCATTERED SHOWERS N OF 28N
BETWEEN 68W-76W AND SCATTERED MODERATE CONVECTION WITH EMBEDDED
TSTMS N OF 28N BETWEEN 55W-60W. AN UPPER LEVEL TROUGH IS
ENHANCING SHOWERS AND TSTMS ACROSS THE WINDWARD ISLANDS THAT
EXTENDS EASTWARD TO 58W. BESIDES THE TROPICAL WAVES ALREADY
DISCUSSED...SURFACE RIDGING AND FAIR WEATHER DOMINATE THE
REMAINDER BASIN.

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

$$
NR


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