[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230539
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE OCT 23 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 60W/61W S OF 21N MOVING W 10-15 KT. WAVE
REMAINS BENEATH THE WESTERN EDGE OF A BROAD UPPER RIDGE
PARTIALLY MASKING THE SATELLITE SIGNATURE AND DISPLACING THE
DEEPEST CONVECTION TO THE E. SCATTERED MODERATE/STRONG
CONVECTION IS FROM 13N-17N BETWEEN 53W-58W WITH CLUSTERS OF
SCATTERED MODERATE CONVECTION COVERING A BROADER AREA FROM
11N-22N BETWEEN 50W-62W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 6N29W 8N45W 11N63W.
SCATTERED/NUMEROUS STRONG CONVECTION IS MOVING OFF AFRICA FROM
9N-12N E OF 17W TO INLAND OVER GUINEA BISSAU AND E GUINEA. SMALL
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 3N-10N BETWEEN 10W-42W.

DISCUSSION...

GULF OF MEXICO...
A STRONG COLD FRONT MOVED INTO THE GULF ON MONDAY AND EXTENDS
FROM A 1008 MB LOW OVER NW MISSISSIPPI ACROSS SE LOUISIANA INTO
THE GULF NEAR 29N91W ALONG 22N95W INTO MEXICO JUST S OF TAMPICO
TO THE E SLOPES OF THE SIERRA MADRE MOUNTAINS. HEAVY SHOWERS AND
STRONG THUNDERSTORMS ARE WITHIN 60/75 NM E OF THE FRONT WITH
SCATTERED SHOWERS W OF THE FRONT...THE EXCEPTION IS ALONG THE
COAST OF TEXAS WHERE RAPID CLEARING IS OCCURRING DUE TO THE DRY
STABLE AIR ASSOCIATED WITH THE DEEP LAYERED TROUGH THAT IS
CURRENTLY OVER THE CENTRAL PLAIN STATES TO THE MISSISSIPPI
VALLEY AND INCLUDING THE FAR W GULF. GALE FORCE NORTHERLY
SURFACE WINDS ARE W OF THE FRONT. AN UPPER HIGH IS CENTERED OVER
NE FLORIDA NEAR 29N83W PROVIDING UPPER DIFFLUENCE TO THE W OF
THE UPPER HIGH ENHANCING THE ACTIVITY ASSOCIATED WITH THE
FRONTAL BOUNDARY. LOW LEVEL SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ARE MOVING ACROSS FLORIDA AND THROUGH THE
FLORIDA STRAITS IN THE RETURN FLOW AROUND A SURFACE HIGH IN THE
W ATLC E OF 85W.

CARIBBEAN SEA...
AN UPPER LEVEL SHEAR AXIS BISECTS THE CARIBBEAN EXTENDING ACROSS
THE VIRGIN ISLANDS W OVER JAMAICA THEN SW TO AN UPPER LOW OVER
THE W COAST OF NICARAGUA IN THE E PACIFIC REGION. DRY SOMEWHAT
STABLE AIR IS N OF THE SHEAR AXIS WHILE MOIST TROPICAL AIR WITH
S AND W UPPER FLOW IS TO THE S. A CONVERGENCE LINE BETWEEN THE
SW UPPER FLOW AND LOW LEVEL EASTERLY SURFACE FLOW IS GENERATING
SCATTERED SHOWERS/THUNDERSTORMS WITHIN 60 NM OF LINE FROM 10N80W
TO 17N83W. THE ITCZ AXIS CROSSES THE N COAST OF SOUTH AMERICA
AND EXTENDING ACROSS PANAMA AND COSTA RICA INTO THE E PACIFIC
REGION GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF
12N E OF 80W TO THE WINDWARD ISLANDS. LIGHT/MODERATE EASTERLY
TRADE WINDS ACROSS THE CARIBBEAN ARE USHERING IN LOW LEVEL
POPCORN TYPE SHOWERS ESPECIALLY E OF 80W.

ATLANTIC OCEAN...
THE UPPER HIGH OVER NE FLORIDA IS GIVING THE W ATLC SOUTHERLY
UPPER FLOW W OF 65W. A SURFACE RIDGE COVERS THE W AND MOST OF
THE CENTRAL ATLC N OF 23N W OF 45W ANCHORED BY A 1026 MB HIGH N
OF BERMUDA NEAR 37N65W. AN UPPER SHEAR AXIS EXTENDS FROM THE
CENTRAL ATLC NEAR 25N55W INTO THE CARIBBEAN OVER THE VIRGIN
ISLANDS WITH A SWATH OF DRY STABLE AIR S OF 23N W OF 63W. A
REMNANT OF A FRONTAL BOUNDARY REMAINS IN THE W/CENTRAL ATLC WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM OF 25N
FROM 59W-67W. A LARGE CUT-OFF UPPER LOW IS IN THE E/CENTRAL ATLC
NEAR 27N37W WITH A 1009 MB SURFACE LOW THAT DEVELOPED TO THE E
OF THE UPPER LOW ON MONDAY CENTERED NEAR 28N35W AND A SURFACE
TROUGH EXTENDING S TO 19N40W. CLUSTERS OF SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS COVERS A BROAD AREA FROM 17N TO BEYOND
32N BETWEEN 30W-40W. WEAK UPPER HIGH IS JUST OFF THE COAST OF
WESTERN SAHARA S OF THE CANARY ISLANDS NEAR 24N19W COVERING THE
REMAINDER OF THE E ATLC. WEAK SURFACE RIDGE COVERS THE E ATLC E
OF 30W WITH DRY STABLE AIR COVERING THE SAME AREA.

$$
WALLACE




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