[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311048
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT AUG 31 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1022 UTC.

...SPECIAL FEATURES...
A TROPICAL WAVE ASSOCIATED WITH A 1008 MB LOW PRESSURE IS COMING
OFF THE AFRICAN COAST. ITS AXIS EXTENDS FROM 20N16W TO THE LOW
NEAR 15N16W TO 10N16N AND IS MOVING W NEAR 5 KT. THE SURFACE
CYCLONIC CIRCULATION ASSOCIATED WITH THE LOW EXTENDS UP TO THE
MIDDLE LEVELS. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS
WITHIN A MODERATE TO HIGH MOIST ENVIRONMENT. STRONG
SOUTHEASTERLY WIND SHEAR IS KEEPING A CLUSTER OF
MODERATE/ISOLATED STRONG CONVECTION NW OF THE LOW PRESSURE
CENTER FROM 13N-18N BETWEEN 17W-22W. ENVIRONMENTAL CONDITIONS
APPEAR CONDUCIVE FOR DEVELOPMENT AND THIS SYSTEM HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE
OF DAYS AS IT MOVES TOWARD THE CAPE VERDE ISLANDS. RAINSHOWERS
AND THUNDERSTORMS ARE EXPECTED IN PORTIONS OF THE CAPE VERDE
ISLANDS IN THE NEXT COUPLE OF DAYS.

...TROPICAL WAVES...
A TROPICAL WAVE ASSOCIATED WITH A 1012 MB LOW EXTENDS AN AXIS
FROM 18N50W TO THE LOW NEAR 15N52W TO 11N54W AND MOVES W-NW NEAR
10 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW A HIGH MOIST
ENVIRONMENT NE OF THE LOW PRESSURE CENTER AND A MODERATE MOIST
ENVIRONMENT ELSEWHERE. SCATTERED MODERATE CONVECTION AND
ISOLATED TSTMS COINCIDE WITH THE AREA OF HIGH MOISTURE AND ARE
FROM 14N-19N BETWEEN 48W-52W.

A TROPICAL WAVE IS MOVING ACROSS THE WESTERN CARIBBEAN SEA WITH
AXIS EXTENDING ALONG 22N78W TO 11N80W AND MOVING W-NW NEAR 15-20
KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A
MODERATE MOIST ENVIRONMENT. SCATTERED SHOWERS AND TSTMS ARE
WITHIN 150 NM E OF THE AXIS FROM 18N-21N AND FROM 13N-16N. A
SMALL CLUSTER OF MODERATE CONVECTION AND TSTMS IS FROM 10N-12N
BETWEEN 79W-81W OR IN THE SOUTHERN AXIS REGION.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR
15N16W TO 10N30W 08N40W 13N47W. BESIDES THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVES ALREADY DISCUSSED...SCATTERED
MODERATE CONVECTION IS FROM 03N-12N E OF 19W AS WELL AS FROM 04N-
08N BETWEEN 36W-44W AND FROM 12N-17N BETWEEN 38W-48W. ISOLATED
SHOWERS ARE FROM 06N-12N BETWEEN 39W-42W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATE NORTHERLY UPPER LEVEL FLOW
CONTINUES TO DOMINATE ACROSS MUCH OF THE GULF THIS MORNING WITH
RELATIVELY DRY AND STABLE CONDITIONS ALOFT W OF 88W. THIS
OVERALL STABILITY IS SUPPORTING A 1014 MB HIGH CENTERED NEAR
26N89W WHICH IS PROVIDING ANTICYCLONIC WIND RANGING FROM 5-10 KT
N OF 22N. AN UPPER LEVEL TROUGH OFF THE EASTERN SEABOARD
SUPPORTS A STATIONARY FRONT AND A 1012 MB LOW PRESSURE CENTER
OVER NORTHERN FLORIDA. THIS FRONTAL SYSTEM IS GENERATING
SCATTERED SHOWERS AND TSTMS OVER THE NE GULF N OF 28N BETWEEN
84W-88W. OTHERWISE...A SURFACE TROUGH IS IN THE BAY OF CAMPECHE
ALONG 22N90W TO 17N93W AND IS GENERATING ISOLATED SHOWERS S OF
20N. FAIR WEATHER IS EXPECTED TO DOMINATE ACROSS THE GULF THIS
WEEKEND SUPPORTED BY SURFACE RIDGING AND STABLE DRY AIR.

CARIBBEAN SEA...
A TROPICAL WAVE IS MOVING ACROSS THE WESTERN CARIBBEAN SEA WITH
AXIS EXTENDING ALONG 22N78W TO 11N80W. EXCEPT FOR TWO SMALL
AREAS OF HIGH MOISTURE...TOTAL PRECIPITABLE WATER IMAGERY SHOW
THE WAVE IS WITHIN A MODERATE MOIST ENVIRONMENT. SCATTERED
SHOWERS AND TSTMS COINCIDE WITH THOSE TWO AREAS OF HIGH MOISTURE
FROM 13N-16N BETWEEN 77W-80W AND FROM 10N-12N BETWEEN 79W-81W.
UPPER LEVEL DIFFLUENCE FROM AN UPPER LOW CENTERED IN THE STRAITS
OF FLORIDA AND A RIDGE CENTERED OVER THE SW GULF IS ENHANCING
ISOLATED SHOWERS WITHIN 120 NM OFF THE HONDURAS COAST W OF 83W.
AN UPPER LEVEL LOW CENTERED N OF PUERTO RICO EXTENDS A TROUGH
AXIS OVER THE CENTRAL-EASTERN BASIN WHICH IS SUPPORTING
SCATTERED SHOWERS N OF 16N BETWEEN 61W-69W.

A TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE LESSER ANTILLES
SUNDAY NIGHT GENERATING RAINSHOWERS.

HISPANIOLA...
ISOLATED SHOWERS ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE
LINGER ACROSS HAITI AND ADJACENT WATERS OF THE WINDWARD PASSAGE.
AN UPPER LEVEL LOW CENTERED N OF PUERTO RICO IS SUPPORTING
SCATTERED SHOWERS N OF 16N BETWEEN 61W-69W INCLUDING THE MONA
PASSAGE AND EASTERN DOMINICAN REPUBLIC. THE UPPER LEVEL LOW N OF
PUERTO RICO IS EXPECTED TO DRIFT WESTWARD OVER HISPANIOLA WHICH
MAY ENHANCE CONVECTIVE ACTIVITY OVER THE WEEKEND.

ATLANTIC OCEAN...
UPPER LEVEL TROUGHINESS OVER THE SW N ATLC IS SUPPORTING
ISOLATED SHOWERS AND TSTMS N OF 22N W OF 74W. FARTHER EAST...AN
UPPER LEVEL ELONGATED LOW SUPPORTS A SURFACE TROUGH ALONG 28N60W
TO 23N72W AND NUMEROUS MODERATE CONVECTION FROM 23N-28N BETWEEN
58W-63W. OTHERWISE...BESIDES THE TROPICAL WAVES ALREADY
DISCUSSED...SURFACE RIDGING AND DRY STABLE AIR DOMINATES THE
REMAINDER BASIN SUPPORTING FAIR WEATHER.

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

$$
NR

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