[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 310604
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
A TROPICAL WAVE ASSOCIATED WITH A 1008 MB LOW PRESSURE IS COMING
OFF THE AFRICAN COAST WITH AXIS EXTENDING FROM 20N15W TO THE LOW
NEAR 14N16W TO 12N16N. THE WAVE IS MOVING W-NW NEAR 5 KT. THE
LOW CYCLONIC CIRCULATION AND A MAXIMUM OF RELATIVE VORTICITY
ALIGNED OR CLOSELY ALIGNED TO THE CIRCULATION CENTER EXTEND UP
TO THE MIDDLE LEVELS. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE
WAVE IS EMBEDDED IN A MODERATE TO HIGH MOIST ENVIRONMENT. A
CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION IS NW OF THE LOW
FROM 13N-18N BETWEEN 17W-21W. 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. CLOUDINESS 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 1013 MB LOW EXTENDS AN AXIS
FROM 18N49W TO THE LOW NEAR 11N51W TO 09N52W WHICH IS MOVING W-
NW NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW A HIGH
MOIST ENVIRONMENT IN THE NORTHERN PART OF THE WAVE N OF 14N BUT
A DRIER ENVIRONMENT IN THE VICINITY OF THE LOW PRESSURE. SMALL
CLUSTERS OF MODERATE CONVECTION ARE WITHIN 220 NM EAST OF THE
WAVE AXIS FROM 13N-18N.

A TROPICAL WAVE IS ENTERING THE WESTERN CARIBBEAN SEA WITH AXIS
EXTENDING ALONG 20N76W TO 10N77W AT 0300 UTC. IT CONTINUES
MOVING WESTWARD BUT SLIGHTLY FASTER...NEAR 15-20 KT. TOTAL
PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A MODERATE TO
HIGH MOIST ENVIRONMENT. SCATTERED SHOWERS AND TSTMS ARE BEING
ENHANCED BY MIDDLE TO UPPER LEVEL DIFFLUENCE NEAR THE WINDWARD
PASSAGE AND EXTEND TO HAITI.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR
14N16W TO 10N30W 08N40W 11N49W. BESIDES THE CONVECTION
ASSOCIATED WITH THE TROPICAL WAVES ALREADY DISCUSSED...SCATTERED
MODERATE CONVECTION IS FROM 05N-12N E OF 18W AS WELL AS FROM 12N-
15N BETWEEN 39W-42W. SIMILAR CONVECTION IS WITHIN 160 NM EITHER
SIDE OF THE MONSOON AXIS BETWEEN 29W-36W AS WELL AS WITHIN 200
NM S BETWEEN 34W-45W.

...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 1015 MB HIGH CENTERED NEAR
27N90W THAT IS PROVIDING MUCH OF THE BASIN N OF 22N WITH
ANTICYCLONIC WIND GENERALLY IN THE RANGE OF 5-10 KT. AN UPPER
LEVEL TROUGH OFFSHORE THE EASTERN CONUS IS SUPPORTING A COLD
FRONT AND A 1013 MB LOW OVER NORTHERN FLORIDA. THIS FRONTAL
SYSTEM IS GENERATING SCATTERED MODERATE CONVECTION AND TSTMS
OVER THE NE GULF N OF 28N E OF 87W. OTHERWISE...A SURFACE TROUGH
ALONG THE WESTERN YUCATAN PENINSULA IS GENERATING SHOWERS OVER
THE EASTERN BAY OF CAMPECHE S OF 21N E OF 93W.

FAIR WEATHER IS EXPECTED TO DOMINATE ACROSS THE GULF THIS
WEEKEND SUPPORTED BY SURFACE RIDGING AND STABLE DRY AIR IN THE
LOWER TO MIDDLE LEVELS.

CARIBBEAN SEA...
A TROPICAL WAVE IS ENTERING THE WESTERN CARIBBEAN SEA WITH AXIS
EXTENDING ALONG 20N76W TO 10N77W AT 0300 UTC. TOTAL PRECIPITABLE
WATER IMAGERY SHOW THE WAVE IS WITHIN A MODERATE TO HIGH MOIST
ENVIRONMENT. MIDDLE TO UPPER LEVEL DIFFLUENCE IS ENHANCING
SCATTERED SHOWERS AND TSTMS IN THE WINDWARD PASSAGE AND HAITI. A
MIDDLE TO UPPER LEVEL LOW CENTERED IN THE FLORIDA STRAITS IS
SUPPORTING SCATTERED/ISOLATED SHOWERS WITHIN 140 NM OF THE
SOUTHERN COAST OF CUBA. UPPER LEVEL DIFFLUENCE FROM THAT UPPER
LOW AND A RIDGE CENTERED OVER THE SW GULF IS ENHANCING ISOLATED
SHOWERS S OF 20N W OF 84W. AN UPPER LEVEL LOW CENTERED N OF
PUERTO RICO EXTENDS A TROUGH AXIS OVER THE EASTERN BASIN WHICH
IS SUPPORTING A CLUSTER OF MODERATE CONVECTION FROM 18N-20N
BETWEEN 66W-69W INCLUDING THE MONA PASSAGE. ISOLATED SHOWERS ARE
FROM 16N-19N BETWEEN 63W-65W.

A TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE LESSER ANTILLES
BY MONDAY MORNING.

HISPANIOLA...
SHOWERS AND TSTMS ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE
ARE AFFECTING HAITI AND ADJACENT WATERS OF THE WINDWARD PASSAGE.
AN UPPER LEVEL LOW CENTERED N OF PUERTO RICO IS SUPPORTING A
CLUSTER OF MODERATE CONVECTION FROM 18N-20N BETWEEN 66W-69W
INCLUDING THE MONA PASSAGE AND EASTERN DOMINICAN REPUBLIC E OF
69W. CONVECTIVE ACTIVITY IS EXPECTED ACROSS HISPANIOLA ON
SATURDAY AND SUNDAY.

ATLANTIC OCEAN...
UPPER LEVEL TROUGHINESS OVER THE SW N ATLC IS SUPPORTING
SCATTERED SHOWERS AND TSTMS OVER THE NORTHERN BAHAMAS FROM 26N-
28N W OF 76W. FARTHER EAST...AN UPPER LEVEL ELONGATED LOW
SUPPORTS A SURFACE TROUGH ALONG 25N66W TO 21N71W AND NUMEROUS
MODERATE CONVECTION FROM 24N-29N BETWEEN 59W-66W.
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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