[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061132
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE AUG 06 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
1052 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE AXIS EXTENDS FROM 25N59W TO 09N62W MOVING W-NW
NEAR 15-20 KT. EXCEPT FOR THE NORTHERN PART OF THE WAVE N OF
23N...TOTAL PRECIPITABLE WATER IMAGERY DEPICT THIS WAVE IS
WITHIN A DRY ENVIRONMENT. METEOSAT-9 SAL TRACKING IMAGERY SHOW
SOME DRY AIR SPREADING OVER THE WAVE ENVIRONMENT WHICH ALONG
WITH STRONG WIND SHEAR IS HINDERING CONVECTION. A CLUSTER OF
MODERATE CONVECTION IS FROM 24N-27N BETWEEN 57W-60W.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR
13N16W TO 09N28W 08N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
STARTS NEAR 08N40W AND CONTINUES TO 10N45W...IT RESUMES WEST OF
A SURFACE TROUGH ASSOCIATED WITH A 1011 MB LOW NEAR 11N49W AND
CONTINUES ALONG 13N53W TO 12N56W. SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS FROM 06N-12N E OF 29W. ISOLATED MODERATE
CONVECTION IS WITHIN 160 NM EITHER SIDE OF THE AXIS BETWEEN 29W-
35W...FROM 06N-11N BETWEEN 39W-48W AS WELL AS FROM 10N-14N
BETWEEN 49W-54W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 0900 UTC...ANTICYCLONIC FLOW IN THE RANGE OF 5-15 KT
SPREADS ACROSS MOST OF THE BASIN ANCHORED BY A 1016 MB HIGH NEAR
25N90W WHICH IS BEING SUPPORTED BY A BROAD MIDDLE TO UPPER LEVEL
RIDGE CENTERED OVER THE NW GULF. A WEAK COLD FRONT EXTENDS FROM
A 1013 MB LOW OVER NORTHERN FLORIDA TO 29N83W 30N87W WITH NO
CONVECTION ASSOCIATED WITH IT AT THE TIME. A SURFACE PREFRONTAL
TROUGH EXTENDS ACROSS THE BAHAMAS TO THE STRAITS OF FLORIDA
ENHANCING SCATTERED RAINSHOWERS FROM 23N-25N BETWEEN 80W-82W.
ANOTHER SURFACE TROUGH IS OVER THE BAY OF CAMPECHE ALONG 22N94W
TO 16N94W. A CLUSTER OF MODERATE CONVECTION WITH EMBEDDED TSTMS
HAS DEVELOPED INLAND SW OF THE TROUGH BEING SUPPORTED BY UPPER
LEVEL DIFFLUENCE. THIS CONVECTION EXTENDS WITHIN 30 NM OFF THE
COAST S OF 20N W OF 94W. OTHERWISE...DRY AIR IN THE LOWER AND
MIDDLE LEVELS IS SUPPORTING FAIR WEATHER OVER THE WESTERN
AND SOUTHERN-CENTRAL GULF.

THE CENTER OF HIGH PRESSURE IS EXPECTED TO DRIFT NW AND PERSIST
OVER THE GULF UNTIL THURSDAY MORNING. SURFACE TROUGHINESS OVER
THE SW GULF IS EXPECTED TO CONTINUE UNTIL THIS AFTERNOON. THE
TROUGH OVER THE BAHAMAS IS EXPECTED TO MOVE WESTWARD AND PROVIDE
TROUGHINESS TO THE EASTERN GULF UNTIL VERY EARLY THURSDAY.
RAINSHOWERS ARE LIKELY TO CONTINUE OVER THE EASTERN GULF.

THE CARIBBEAN SEA...
EXCEPT FOR THE SOUTHERN CARIBBEAN S OF 11N...VERY DRY AIR FROM A
SAHARAN OUTBREAK CONTINUES TO SPREAD ACROSS THE BASIN IN THE
LOWER AND MIDDLE LEVELS WHICH ALONG WITH STRONG WIND SHEAR IS
INHIBITING CONVECTION. A TROPICAL WAVE IS MOVING ACROSS THE
LESSER ANTILLES EMBEDDED WITHIN A DRY AIR ENVIRONMENT AS
DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. RAINSHOWERS HAS
BEEN REPORTED NEAR ST LUCIA AND ST VINCENT WITHIN THE LAST HOUR
WHILE THE OTHER ANTILLES HAS BEEN REPORTING WIDESPREAD DUST.
TRADEWINDS RANGING FROM 20-25 KT ARE OVER THE CENTRAL-SOUTHERN
CARIBBEAN NEAR THE COAST OF COLOMBIA WHILE WINDS OF 5-15 KT ARE
ELSEWHERE IN THE BASIN. ISOLATED MODERATE CONVECTION/TSTMS ARE
WITHIN 60 NM OFF THE COASTS OF COSTA RICA AND PANAMA ASSOCIATED
WITH THE MONSOON TROUGH AXIS.

WINDS OVER THE CENTRAL-SOUTHERN CARIBBEAN ARE EXPECTED TO
SUBSIDE TONIGHT. RAINSHOWERS ACTIVITY ASSOCIATED WITH THE
TROPICAL WAVE ARE EXPECTED TO DEVELOP S OF PUERTO RICO...THE
MONA PASSAGE AND DOMINICAN REPUBLIC THIS AFTERNOON BEING
ENHANCED BY AN UPPER LEVEL LOW CENTERED IN THE BASIN.

HISPANIOLA...
IN THE UPPER LEVEL...AN ELONGATED LOW EXTENDS ACROSS THE ISLAND
FROM THE W ATLC TO THE SOUTHERN CARIBBEAN. THIS IS SUPPORTING
LOW VALUES OF WIND SHEAR OVER THE NORTHERN ISLAND...HOWEVER DRY
AIR SUBSIDENCE IS ALLOWING FAIR WEATHER. RAINSHOWERS AND TSTMS
ARE EXPECTED THIS AFTERNOON/EARLY EVENING ENHANCED BY DAYTIME
HEATING AND SOME MOISTURE CARRIED TOWARDS THE ISLAND BY THE
TROPICAL WAVE THAT HAS ENTERED THE EASTERN CARIBBEAN.

THE WAVE IS EXPECTED TO START MOVING ACROSS THE ISLAND WEDNESDAY
MORNING AND RAINSHOWERS ARE LIKELY TO DEVELOP/CONTINUE THROUGH
EARLY THURSDAY.

THE ATLANTIC OCEAN...
AS OF 0900 UTC...THE FORMER STATIONARY FRONT OVER THE SW N ATLC
HAS TRANSITIONED TO A COLD FRONT WHICH EXTENDS FROM 30N71W TO
29N76W 29N81W TO A 1013 MB LOW OVER NORTHERN FLORIDA. A
PREFRONTAL TROUGH EXTENDS ACROSS THE BAHAMAS TO THE STRAITS OF
FLORIDA ALONG 27N75W TO 25N79W 24N82W. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE FROM 21N-28N W OF 74W...INCLUDING THE STRAITS
OF FLORIDA. A SURFACE TROUGH ASSOCIATED WITH A 1011 MB LOW IS
EMBEDDED WITHIN THE ITCZ AXIS WITH NO DEEP CONVECTION ASSOCIATED
WITH IT AT THE TIME. OTHERWISE...BESIDES THE TROPICAL WAVE
ALREADY DISCUSSED...SURFACE RIDGING AND FAIR WEATHER SUPPORTED
BY LOWER-MIDDLE LEVEL DRY AIR DOMINATE THE REMAINDER BASIN.

A NEW TROPICAL WAVE COULD BE COMING OFF THE WEST AFRICAN COAST
LATER TODAY.

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

$$
RAMOS

This weather bulletin was brought to you by:
www.nashvilleweather.net