[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 292336
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 29 2008

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2245 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 16W/17W S OF 18N MOVING W AT 15 KT WITH A
1008 MB LOW ALONG THE WAVE NEAR 12N. WAVE IS EMBEDDED WITHIN A
DEEP LAYER OF MOISTURE BASED ON THE MIMIC-TPW. A MID LEVEL
ROTATION IS JUST TO THE NE OF THE SURFACE LOW. ALTHOUGH THIS
WAVE SHOWS SOME SIGNS OF ORGANIZATION...DEVELOPMENT...IF
ANY...IS EXPECTED TO BE SLOW TO OCCUR. SCATTERED/NUMEROUS STRONG
CONVECTION IS N OF THE SURFACE LOW FROM 12N-16N BETWEEN 17W-19W.

TROPICAL WAVE IN THE CENTRAL ATLC IS TILTED FROM 21N46W TO 5N50W
MOVING W 15-20 KT. HIGH AMPLITUDE WAVE WITH WELL DEFINED
INVERTED-V CURVATURE IN THE LOW CLOUDS. WAVE IS EMBEDDED WITHIN
DRY STABLE AIR...THUS ASSOCIATED SHOWERS/CONVECTION.

TROPICAL WAVE IS IN THE CARIBBEAN ALONG 69W S OF 19N MOVING W
15-20 KT. THIS WAVE IS AT THE LEADING EDGE OF LARGE SURGE OF
AFRICAN DUST THAT CONTINUES TO SPREAD ACROSS THE ATLC INTO THE
CARIBBEAN AND BENEATH THE E EDGE OF AN UPPER RIDGE THAT COULD
PRODUCE SOME ISOLATED SHOWERS FROM 14N-17N BETWEEN THE WAVE AND
73W.

TROPICAL WAVE THAT WAS ALONG 94W IS INLAND OVER S MEXICO AND IN
THE E PACIFIC REGION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N19W 9N26W 13N43W 8N62W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 75 NM OF LINE FROM
THE COAST OF AFRICA NEAR 11N15W TO 9N20W AND FROM 7N-11N BETWEEN
31W-35W.

...DISCUSSION...

GULF OF MEXICO...
A MID LEVEL LOW IS JUST OFF THE S/CENTRAL COAST OF LOUISIANA
NEAR 29N91W AND COUPLED WITH A SURFACE TROUGH INLAND OVER SE
LOUISIANA IS PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
N OF 27N BETWEEN 88W-94W. OTHERWISE BROAD UPPER RIDGE COVERS THE
REMAINDER OF THE GULF GIVING THE ENTIRE GULF NE UPPER FLOW. A
SURFACE RIDGE COVERS THE E GULF EXTENDING FROM THE W ATLC ACROSS
CENTRAL FLORIDA AND IS EXPECTED TO REMAIN TO OVER THE WEEKEND.
DIFFLUENCE ALOFT IS ENHANCING CLUSTERS OF SCATTERED SHOWERS/
THUNDERSTORMS OVER THE E GULF E OF 90W INCLUDING CUBA AND THE
YUCATAN WITH THE SEABREEZE THUNDERSTORMS OVER FLORIDA MOVING OFF
THE E COAST OF FLORIDA. THE W GULF REMAINS RATHER CLEAR THIS
EVENING.

CARIBBEAN SEA...
AN UPPER LOW IS OVER THE GULF OF HONDURAS EXTENDING AN UPPER
TROUGH NE TO OVER E/CENTRAL CUBA TO THE TURKS AND CAICOS. AN
UPPER RIDGE COVERS THE S CARIBBEAN S OF 17N FROM THE ABC ISLANDS
AND CENTRAL VENEZUELA TO OVER NICARAGUA. THIS IS PROVIDING
DIFFLUENCE ALOFT TO GENERATE AN AREA OF SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS S OF 16N W OF 78W TO INLAND OVER CENTRAL
AMERICA. THE SCATTERED SHOWERS/THUNDERSTORMS OVER THE E GULF
EXTEND S OVER W CUBA TO 21N E OF 79W TO OVER THE YUCATAN
CHANNEL. MODERATE/STRONG SUBSIDENCE AND DRY AIR COVER THE E
CARIBBEAN E OF 67W AS WELL AS AFRICAN DUST THAT COVERS THE
REMAINDER OF THE TROPICAL ATLC. MODERATE/STRONG EASTERLY TRADE
WINDS DOMINATE MUCH OF THE CARIBBEAN DUE TO THE SURFACE RIDGE
OVER THE ATLC. A LARGE ERUPTION OF THE SOUFRIERE HILLS VOLCANO
IN MONTSERRAT OCCURRED EARLIER TODAY...PLEASE SEE THE AFOS/WMO
BULLETIN FVXX22 KNES FOR MORE DETAILS.

ATLANTIC OCEAN...
THE UPPER RIDGE THAT IS GIVING THE GULF OF MEXICO NE UPPER FLOW
EXTENDS ACROSS THE W ATLC ALONG 30N TO 65W. NARROW UPPER TROUGH
ENTERS THE REGION NEAR 32N59W EXTENDING ALONG 28N61W TO 26N65W.
THIS COUPLED WITH THE UPPER TROUGH EXTENDING ACROSS E/CENTRAL
CUBA TO THE TURKS AND CAICOS IS GENERATING CLUSTERS OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE W ATLC N OF 24N W OF
65W. AFTERNOON SEABREEZE INDUCED THUNDERSTORMS THAT DEVELOPED
OVER THE FLORIDA PENINSULA HAVE MOVED OFF THE E COAST OF FLORIDA
BETWEEN PALM BEACH TO DAYTONA BEACH W OF 79W. LARGE UPPER HIGH
IS ANCHORED IN THE CENTRAL ATLC NEAR 21N42W WHILE A SECOND UPPER
RIDGE IS BEGINNING TO PUSH W OFF THE COAST OF W AFRICA. AFRICAN
DUST COVERS THE COVERS THE TROPICAL ATLC INTO THE E CARIBBEAN S
OF 25N. A SURFACE RIDGE DOMINATES THE ATLC ANCHORED BY A 1024
AND 1025 MB HIGH N OF THE REGION WITH A 1021 MB HIGH SE OF
BERMUDA NEAR 27N60W AND THE RIDGE CONTINUING W TO OVER THE E
GULF OF MEXICO.

$$
WALLACE


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