[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181033
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI MAY 18 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ALONG 8N9W 5N17W 6N36W 4N52W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N TO JUST S OF THE
EQUATOR BETWEEN 2W-9W. CLUSTERS OF SIMILAR CONVECTION ARE FROM
10N TO THE ITCZ AXIS BETWEEN 40W-53W. CLUSTERS OF SCATTERED
MODERATE CONVECTION ARE FROM 3N-8N BETWEEN 9W-25W.

...DISCUSSION...

GULF OF MEXICO...
UPPER RIDGE EXTENDS ACROSS MEXICO INTO THE W GULF ALONG 96W.
BROAD UPPER TROUGH DOMINATES THE E US AND THE E GULF MOVING
INTO THE W ATLC. THE ASSOCIATED FRONTAL BOUNDARY EXTENDS FROM
THE W ATLC TO A 1012 MB LOW OVER NE FLORIDA NEAR 30N82W WITH A
COLD FRONT EXTENDING INTO THE GULF TO NEAR 26N88W WHERE IT
DISSIPATES TO NEAR 26N94W. THIS REMAINS A WEAK FRONT AND WITH
THE DRY AIR IN PLACE ONLY WIDELY ISOLATED SHOWERS ARE BEING
GENERATED ALONG THE FRONTAL BOUNDARY. HIGH PRESSURE CONTINUES TO
BUILD BEHIND THE FRONT WITH NORTHERLY WINDS BRIDGING THE
FRONT ACROSS THE ENTIRE GULF. THE FRONT WILL CONTINUE TO DRIFT
SLOWLY S ACROSS THE E GULF AND GRADUALLY DISSIPATE OVER THE W
GULF WITH THE MAIN ENERGY MOVING E INTO THE W ATLC.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO DIPS INTO THE NW
CARIBBEAN N OF 20N W OF 74W. BROAD UPPER LEVEL E/W RIDGE EXTENDS
FROM SOUTH AMERICA ACROSS CENTRAL AMERICA COVERING THE REMAINDER
OF THE CARIBBEAN. THE UPPER RIDGE IS ENHANCING SCATTERED
MODERATE/ISOLATED STRONG CONVECTION WITHIN 90/120 NM OF LINE
FROM 16N77W ACROSS E CUBA AND HAITI INTO THE W ATLC NEAR 20N74W.
A SURFACE TROUGH EXTENDS FROM THE CAYMAN ISLANDS S ALONG 15N81W
TO NEAR 10N80W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S
OF 17N W OF THE TROUGH TO INLAND OVER CENTRAL AMERICA. THE ITCZ
IN THE E PACIFIC EXTENDS ACROSS COLOMBIA/PANAMA AND SE COSTA
RICA COUPLED WITH THE 1008 MB LOW ALONG THE COAST OF PANAMA NEAR
10N78W ARE GENERATING SCATTERED MODERATE/STRONG CONVECTION S OF
13N FROM 75W TO THE SURFACE TROUGH. ALTHOUGH SOME HIGH CLOUDS
ARE OBSERVED OVER THE E CARIBBEAN...DRY CONDITIONS DOMINATE THAT
AREA TONIGHT. MODERATE/STRONG EASTERLY TRADE WINDS DOMINATE THE
CARIBBEAN.

ATLANTIC OCEAN...
UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS INTO THE W ATLC W
OF 72W WITH THE ASSOCIATED FRONTAL BOUNDARY EXTENDING THROUGH
32N79W TO THE 1012 MB LOW OVER NE FLORIDA. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE WITHIN 90 NM E OF THE FRONT N OF 29N.
EMBEDDED WITHIN THE UPPER TROUGH IS A 1010 MB LOW OVER THE NE
BAHAMAS NEAR 27N76W WITH A SURFACE TROUGH EXTENDING TO CENTRAL
CUBA NEAR 22N78W. AN UPPER RIDGE TO THE E IS ENHANCING SCATTERED
MODERATE/ISOLATED STRONG CONVECTION TO THE E OF THE SURFACE
FEATURES WITHIN 150/200 NM OF LINE FROM OVER CUBA NEAR 21N75W
ALONG 25N70W TO BEYOND 32N69W. DEEP LAYERED LOW COVERS THE
CENTRAL ATLC N OF 18N BETWEEN 39W-56W WITH THE UPPER LOW NEAR
29N50W AND THE 1018 MB SURFACE LOW NEAR 29N51W. A SURFACE TROUGH
EXTENDS FROM 31N49W ALONG 27N47W TO 23N50W. THESE FEATURES ARE
EMBEDDED WITHIN DRY AIR AND ARE ONLY ABLE TO GENERATE A NARROW
BAND OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM E
OF THE SURFACE TROUGH BETWEEN 24N-28N. AN E/W UPPER TROUGH IN
THE NE ATLC IS ALONG 30N FROM EXTENDING FROM OVER MOROCCO TO 35W
COVERING THE AREA N OF 25N. BROAD UPPER RIDGE EXTENDS E/W ACROSS
THE TROPICAL ATLC ALONG 5N/6N TO AN UPPER HIGH NEAR 6N48W. THIS
UPPER RIDGE IS ADVECTING TROPICAL MOISTURE ACROSS THE E TROPICAL
ATLC...HOWEVER DUE TO THE DRY AIR AND AFRICAN DUST PRESENT NO
SHOWERS AND CLOUDS ARE FORMING. AT THE SURFACE...A RIDGE
DOMINATES THE ATLC W OF 65W WITH A WEAKNESS IN THE CENTRAL ATLC
IN THE REGION OF THE DEEP LAYERED LOW.

$$
WALLACE




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