[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 090002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED AUG 08 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH WWW UTC.

...SPECIAL FEATURE...

TROPICAL STORM ERNESTO IS CENTERED NEAR 18.7N 91.5W...AS OF 0000
UTC...OR ABOUT 15 NM ENE OF CIUDAD DEL CARMEN MEXICO. ERNESTO IS
MOVING W AT 7 KT. MINIMUM CENTRAL PRESSURE IS 994 MB WITH
MAXIMUM SUSTAINED WINDS OF 45 KT WITH GUSTS TO 55 KT. ERNESTO IS
ABOUT TO EMERGE BACK OVER WATER AND THERE IS A SMALL WINDOW FOR
SOME STRENGTHENING BEFORE MOVING BACK OVER LAND LATER TOMORROW.
PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT5/WTNT25 KNHC AND THE PUBLIC ADVISORY UNDER
AWIPS/WMO MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 17N-20N BETWEEN
87W-97W...AND FROM 20N-25N BETWEEN 91W-97W.

TROPICAL WAVE IS ALONG 18N35W TO A 1010 MB SURFACE LOW AT 14N36W
MOVING W NEAR 12 KT. LOW-LEVEL CYCLONIC FLOW IS AROUND THE LOW
CENTER AND THE WAVE. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS MAINLY W OF THE LOW CENTER FROM 14N-16N BETWEEN
37W-40W...AND FROM 13N-14N BETWEEN 34W-36W. THE SYSTEM HAS
BECOME SLIGHTLY BETTER ORGANIZED AND UPPER LEVEL CONDITIONS
COULD BECOME MORE CONDUCIVE FOR FURTHER DEVELOPMENT OF THE
SYSTEM OVER THE NEXT COUPLE OF DAYS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 23N54W TO 17N59W MOVING NW NEAR 20 KT.
THIS OPEN WAVE IS THE REMNANTS OF T.S. FLORENCE THAT DISSIPATED
SEVERAL DAYS AGO. SATELLITE IMAGERY INDICATES BROAD LOW-LEVEL
CYCLONIC FLOW IS AROUND THE WAVE AXIS. THE WAVE ALSO LIES IN THE
MIDDLE OF A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 19N-23N BETWEEN 56W-61W.

TROPICAL WAVE IS MOVING THROUGH THE CENTRAL CARIBBEAN ALONG
20N71W TO 12N74W MOVING W NEAR 15-20 KT. A LARGE AREA OF
ENHANCED DEEP LAYER MOISTURE IS PRESENT ACROSS THE CENTRAL AND
EASTERN CARIBBEAN ASSOCIATED WITH THE WAVE AS WELL AS AN UPPER
LEVEL LOW CENTERED N OF JAMAICA NEAR 19N77W. THE UPPER LEVEL LOW
IS PROVIDING A LARGE AREA OF DIFFLUENCE ALOFT ACROSS THE
CENTRAL AND EASTERN CARIBBEAN. IT IS HARD TO DIFFERENTIATE WHAT
AREAS OF CONVECTION ARE ASSOCIATED WITH THE WAVE AND WITH THE
UPPER LOW. REGARDLESS OF THE CAUSE...SCATTERED STRONG CONVECTION
IS FROM 15N-17N BETWEEN 67W-74W...AND FROM 19N-21N BETWEEN
71W-75W. SCATTERED MODERATE CONVECTION IS FROM 17N-20N BETWEEN
66W-71W. HEAVY RAINFALL AND FLOODING ALONG WITH MUDSLIDES ARE
POSSIBLE ACROSS MUCH OF THE NORTHERN CARIBBEAN ISLANDS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
MAURITANIA AT 18N16W WHERE IT CONTINUES OVER WATER ALONG 16N24W
15N31W. THE ITCZ BEGINS ON THE W SIDE OF A TROPICAL WAVE/LOW
ALONG 12N38W 9N48W 9N57W. SCATTERED MODERATE CONVECTION IS FROM
10N-11N BETWEEN 39W-43W. SCATTERED STRONG CONVECTION IS FROM
7N-9N BETWEEN 46W-50W.

...DISCUSSION...

THE GULF OF MEXICO...
TROPICAL STORM ERNESTO IS BRINGING WIND AND RAIN TO THE SW GULF
OF MEXICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 25N
BETWEEN 90W-98W. SEE SPECIAL FEATURES FOR MORE DETAILS ABOUT
ERNESTO. THE REMAINDER OF THE GULF WATERS ARE MOSTLY CLEAR DUE
TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE...OUTFLOW FROM
ERNESTO...THAT COVERS THE NORTHERN HALF OF THE BASIN. AN UPPER
LEVEL TROUGH TO THE N OVER THE EASTERN CONUS IS HELPING SUPPORT
SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE NE GULF COAST AND
ACROSS PORTIONS OF THE FLORIDA PENINSULA. CYCLONIC FLOW IS
ACROSS THE SOUTHERN GULF AROUND ERNESTO...WHILE LIGHT
ANTI-CYCLONIC FLOW IS ACROSS THE NORTHERN GULF AROUND A WEAK
SURFACE RIDGE. STRONG WINDS AND RAIN WILL REMAIN OVER THE SW
GULF AS ERNESTO EMERGES OVER WATER AND MAKES A SECOND LANDFALL
LATER TOMORROW. WEAK SURFACE RIDGING WILL BUILD ACROSS THE BASIN
WITH SHOWERS/THUNDERSTORMS REMAINING OVER THE NE GULF COAST.

THE CARIBBEAN SEA...
A FEW SHOWERS REMAIN OVER THE FAR NW CARIBBEAN ASSOCIATED WITH
TROPICAL STORM ERNESTO MOVING ACROSS THE YUCATAN PENINSULA. AN
UPPER LEVEL LOW COVERS MUCH OF THE BASIN CENTERED N OF JAMAICA
NEAR 19N77W. DRY AIR ALOFT IS WRAPPING AROUND THE NW SIDE OF THE
LOW...WHILE MOISTURE FROM ERNESTO IS BEGIN DRAWN AROUND THE
SOUTHERN PORTION AND INTO THE DIFFLUENT E SIDE OF THE LOW. A
TROPICAL WAVE IS ALSO ACROSS THE CENTRAL CARIBBEAN FROM CENTRAL
HISPANIOLA TO N OF COLOMBIA. THE COMBINATION OF THE WAVE AND THE
UPPER LOW IS SUPPORTING SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE
NORTHERN CARIBBEAN INCLUDING PUERTO RICO...HISPANIOLA...AND
EASTERN CUBA. HEAVY RAINFALL...FLOODING...AND MUDSLIDES ARE
POSSIBLE IN AREAS THAT HAVE ALREADY RECEIVED LARGE AMOUNTS OF
PRECIPITATION. SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SW
CARIBBEAN INCLUDING COSTA RICA AND PANAMA ASSOCIATED WITH THE E
PACIFIC MONSOON TROUGH THAT EXTENDS THROUGH BOTH COUNTRIES TO
NORTHERN COLOMBIA. EXPECT MOIST CONDITIONS TO REMAIN OVER THE
CENTRAL CARIBBEAN AND BEGIN TO SPREAD OVER THE WESTERN CARIBBEAN
AS THE WAVE CONTINUES WESTWARD.

THE ATLANTIC OCEAN...
BROAD SURFACE RIDGING COVERS THE ATLC ANCHORED BY A 1025 MB HIGH
NEAR 33N48W. DRY AIR ALOFT BETWEEN AN UPPER LEVEL RIDGE CENTERED
NEAR 34N69W AND AN UPPER LEVEL LOW OVER THE N CENTRAL CARIBBEAN
IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE W ATLC. AN AREA
OF SHOWERS/THUNDERSTORMS IS JUST OFFSHORE OF N FLORIDA
ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS.
SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE ALSO N OF THE
CENTRAL CARIBBEAN TIED TO THE UPPER LEVEL LOW MENTIONED
ABOVE...AND A TROPICAL WAVE IN THE CENTRAL CARIBBEAN. AN UPPER
LEVEL TROUGH ALONG 34N53W TO 27N60W IS SUPPORTING A SURFACE
TROUGH ALONG 30N64W TO 26N67W. ISOLATED SHOWERS ARE WITHIN 100
NM E OF THE AXIS. A TROPICAL WAVE NE OF THE NORTHERN LEEWARD
ISLANDS IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM
19N-23N BETWEEN 55W-62W. BROAD UPPER LEVEL RIDGING COVERS THE
REMAINDER OF THE TROPICAL ATLC EXCEPT FOR A BROAD UPPER TROUGH
ALONG 27W. VISIBLE SATELLITE IMAGERY INDICATES THAT A BROAD AREA
OF AFRICAN DUST EXTENDS ACROSS THE ATLC AROUND THE TWO TROPICAL
WAVES SUPPORTING FAIR CONDITIONS.

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

$$
WALTON





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