[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080547
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU AUG 08 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0522 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS NEAR THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 21N25W TO 12N26W MOVING W NEAR 10 KT. A SURGE OF
DEEP MOISTURE IS TRAILING THE WAVE AS DEPICTED ON THE TOTAL
PRECIPITABLE WATER IMAGERY WITH DRY SAHARAN AIR PRECEDING ITS
AXIS AS SEEN ON METEOSAT IMAGERY. N OF THE MONSOON TROUGH
AXIS...THERE IS NO CONVECTION ASSOCIATED WITH THE WAVE.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM 21N71W TO 09N71W MOVING W NEAR 10 KT. THE WAVE IS
EMBEDDED IN A LIGHT TO MODERATE MOIST ENVIRONMENT AS DEPICTED ON
TOTAL PRECIPITABLE WATER IMAGERY. AN UPPER LEVEL LOW CENTERED
NEAR 23N73W WHICH EXTENDS A TROUGH ACROSS THE CENTRAL-SOUTHERN
CARIBBEAN SUPPORTS LOW DEEP LAYER ENVIRONMENTAL WIND
SHEAR...THUS ENHANCING SCATTERED MODERATE CONVECTION AND TSTMS
OVER THE HISPANIOLA...WINDWARD PASSAGE AND EASTERN CUBA. S OF
18N...THERE IS NO CONVECTION ASSOCIATED WITH THIS WAVE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR
14N17W TO 10N26W 07N39W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
STARTS NEAR 07N39W AND CONTINUES ALONG 06N47W TO 06N56W. BESIDES
THE CONVECTION ASSOCIATED WITH THE WAVE NEAR THE CAPE VERDE
ISLANDS ALREADY DISCUSSED...SCATTERED MODERATE CONVECTION IS
FROM 05N-14N E OF 32W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0300 UTC...ANTICYCLONIC FLOW IN THE RANGE OF 5-15 KT
SPREADS ACROSS THE BASIN W OF 90W N OF 22N ANCHORED BY A 1014 MB
HIGH CENTERED NEAR 27N92W. SURFACE TROUGHINESS IS E OF 90 W
WHERE A TROUGH AXIS EXTENDS FROM 29N83W TO 24N83W...ACROSS
WESTERN CUBA TO 21N83W IN THE W CARIBBEAN. THERE IS A HIGH MOIST
ENVIRONMENT AND LOW DEEP LAYER ENVIRONMENTAL WIND SHEAR IN THIS
REGION OF THE GULF WHICH IS SUPPORTING SCATTERED RAINSHOWERS
WITHIN 160 NM EITHER SIDE OF THE TROUGH AXIS S OF 27N.
OTHERWISE...DRY AIR SUBSIDENCE IS SUPPORTING FAIR WEATHER OVER
THE WESTERN GULF.

THE CENTER OF HIGH PRESSURE IS EXPECTED TO DISSIPATE EARLY ON
THURSDAY. THE SURFACE TROUGH OVER THE E GULF WILL DRIFT W-NW
WITHIN THE NEXT 48 HOURS GENERATING RAINSHOWERS OVER THE CENTRAL
AND WESTERN GULF.

CARIBBEAN SEA...
TOTAL PRECIPITABLE WATER IMAGERY SHOW A MODERATE TO HIGH MOIST
ENVIRONMENT OVER THE WESTERN CARIBBEAN WHERE UPPER LEVEL
DIFFLUENCE FROM A BROAD HIGH CENTERED OVER LOUISIANA AND A LOW
ACROSS THE CENTRAL-SOUTHER CARIBBEAN IS ENHANCING SCATTERED
MODERATE CONVECTION/ISOLATED TSTMS. SIMILAR CONVECTION IS THE
SOUTHERN BASIN S OF 10N E OF 78W...HOWEVER ASSOCIATED WITH THE
MONSOON TROUGH AXIS WHICH EXTENDS FROM THE E PACIFIC TO A LOW
CENTER OVER NORTHERN COLOMBIA. A TROPICAL WAVE IS MOVING ACROSS
THE CENTRAL CARIBBEAN WITH THE NORTHERN PART OF ITS AXIS
CURRENTLY OVER CENTRAL HISPANIOLA WHERE ALONG WITH THE UPPER
LEVEL DIFFLUENCE IS SUPPORTING SCATTERED MODERATE CONVECTION AND
TSTMS OVER THIS ISLAND...THE WINDWARD PASSAGE AND EASTERN CUBA.
S OF 18N...THERE IS NO CONVECTION ASSOCIATED WITH THIS WAVE
UNFAVORED BY DRY AIR AND HIGH VALUES OF DEEP LAYER ENVIRONMENTAL
WIND SHEAR. A SURFACE TROUGH ASSOCIATED WITH A 1009 MB LOW
EXTENDS FROM 17N63W TO 10N63W. SCATTERED MODERATE
CONVECTION/ISOLATED TSTMS ARE WITHIN 120 NM W OF THE AXIS FROM
12N-14N.

BOTH THE WAVE AND THE TROUGH ARE EXPECTED TO CONTINUE MOVING
WESTWARD WITHIN THE NEXT 48 HOURS GENERATING RAINSHOWERS OVER
THE CENTRAL AND SOUTHERN CARIBBEAN. ANOTHER SURFACE TROUGH IS
EXPECTED TO MOVE ACROSS THE LESSER ANTILLES FRIDAY MORNING
INCREASING THE CHANCES OF PRECIPITATION.

HISPANIOLA...
A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN WITH THE
NORTHERN PART OF ITS AXIS CURRENTLY OVER CENTRAL HISPANIOLA
WHERE ALONG WITH THE UPPER LEVEL DIFFLUENCE IS SUPPORTING
SCATTERED MODERATE CONVECTION AND TSTMS OVER THE ISLAND...THE
WINDWARD PASSAGE AS WELL AS EASTERN CUBA. RAINSHOWERS ARE
EXPECTED TO CONTINUE TO AFFECT THE ISLAND THROUGH LATE
THURSDAY...HOWEVER WEATHER CONDITIONS IMPROVE ON EARLY FRIDAY
WHEN A DRY AIRMASS IS EXPECTED TO MOVE ACROSS THE ISLAND.

ATLANTIC OCEAN...
THE ELONGATED UPPER LOW CENTERED OVER THE SE BAHAMAS IS
ENHANCING ISOLATED SHOWERS AND TSTMS E OF THESE ISLANDS FROM 24N-
27N BETWEEN 72W-75W. A PREFRONTAL SURFACE TROUGH SUPPORTED BY AN
UPPER LEVEL NARROW TROUGH EXTENDS FROM 32N59W TO 26N63W.
ISOLATED SHOWERS ARE WITHIN 300 NM W OF ITS AXIS...HOWEVER E OF
ITS AXIS A CLUSTER OF MODERATE CONVECTION WITH EMBEDDED TSTMS IS
FROM 28N-33N BETWEEN 53W-58W. ANOTHER SURFACE TROUGH EXTENDS
FROM 13N52W TO 09N54W WITH SCATTERED MODERATE CONVECTION WITHIN
120 NM E OF ITS AXIS FROM 10N-12N. OTHERWISE...BESIDES THE TROPICAL
WAVE ALREADY DISCUSSED...SURFACE RIDGING AND FAIR WEATHER
SUPPORTED BY LOWER-MIDDLE LEVELS DRY AIR DOMINATE THE REMAINDER
BASIN.

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

$$
RAMOS


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