[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 110502
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU OCT 11 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
0345 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 59W S OF 16N MOVING W 15-20 KT. THIS WAVE
HAS VIRTUALLY NO SATELLITE SIGNATURE WITH ANY SHOWERS ACTIVITY
IN THE VICINITY DUE TO AN UPPER LEVEL FEATURES.

TROPICAL WAVE ALONG 67W/68W S OF 18N. THIS WAVE HAS BEEN
RELOCATED SEVERAL TIMES IN THE PAST COUPLE OF DAYS QUESTIONING
THE VALIDITY OF THE CURRENT LOCATION. WAVE IS MOVING INTO A
BROAD AREA OF SW AND WILL BECOME EVEN MORE DIFFICULT TO TRACK IN
THE COMING DAYS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N13W 7N29W 9N51W 10N63W. CLUSTERS
OF SCATTERED MODERATE/STRONG CONVECTION IS FROM 2N-10N BETWEEN
20W-40W AND FROM 6N-11N BETWEEN 40W-51W. THE CONVECTION W OF 51W
IS DUE TO AN UPPER LEVEL FEATURE...SEE BELOW.

DISCUSSION...
GULF OF MEXICO...
BROAD DEEP LAYERED TROUGH COVERS MUCH OF THE GULF ANCHORED BY A
LARGE UPPER LOW JUST S OF THE GREAT LAKES AREA EXTENDING AN
ASSOCIATED COLD FRONT INTO THE GULF ACROSS NE FLORIDA ENTERING
THE GULF JUST N OF TAMPA EXTENDING WSW TO THE COAST OF MEXICO
JUST N OF TAMPICO. DUE TO DRY CONTINENTAL AIR FILTERING S OVER
THE GULF...THERE IS ONLY WIDELY ISOLATED SHOWERS ALONG THE
FRONTAL BOUNDARY. BROAD UPPER RIDGE ANCHORED OVER MEXICO IS
REINFORCING THE DRY AIR OVER INTO THE GULF. AN UPPER RIDGE
EXTENDS EASTWARD ACROSS S MEXICO INTO THE CARIBBEAN PRODUCING
UPPER DIFFLUENCE ACROSS THE FAR S GULF GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE THE BAY OF CAMPECHE S
OF 21N AND IN THE YUCATAN CHANNEL. THUS THE REMAINDER OF THE
GULF REMAINS RATHER CLEAR TONIGHT.

CARIBBEAN SEA...
A WEAKENING 1005 MB LOW REMAINS INLAND OVER BELIZE BUT IS
BEGINNING TO LOSE DEFINITION. A BROAD UPPER RIDGE EXTENDS ACROSS
S MEXICO AND THE YUCATAN PENINSULA EXTENDING A RIDGE AXIS
THROUGH THE WINDWARD PASSAGE COVERING THE CARIBBEAN TO NEAR 68W.
UPPER DIFFLUENCE AND AN ABUNDANCE OF TROPICAL MOISTURE ARE
GENERATING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 150 NM OF LINE
FROM HAITI NEAR 19N73W TO OFF THE COAST OF HONDURAS NEAR 17N85W.
AN UPPER RIDGE EXTENDING FROM AN UPPER HIGH IN THE W TROPICAL
ATLC EXTENDS ACROSS THE LESSER ANTILLES TO 65W INDUCING AN UPPER
TROUGH BETWEEN 65W-68W AND GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS W OF 67W TO OVER THE LESSER ANTILLES. LOW LEVEL
AND UPPER LEVEL CONVERGENCE IS GENERATING SCATTERED SHOWERS/
THUNDERSTORMS OVER THE FAR SW CARIBBEAN S OF 11N W OF 81W TO
OVER W PANAMA AND ALL OF COSTA RICA.

ATLANTIC OCEAN...
THE DEEP LAYERED TROUGH OVER THE E US INTO THE GULF OF MEXICO
HAS MOVED INTO THE W ATLC W OF 74W WITH THE ASSOCIATED COLD
FRONT EXTENDING ALONG THE COAST FROM NORTH CAROLINA ACROSS
FLORIDA NEAR JACKSONVILLE AND INTO THE GULF OF MEXICO. DUE TO
DRY CONTINENTAL AIR FILTERING E OFF THE COAST OF THE US...NO
SHOWER ACTIVITY IS NOTED. THE UPPER RIDGE FROM THE CARIBBEAN
EXTENDS THROUGH THE WINDWARD PASSAGE TO NEAR 25N63W WITH ENOUGH
DIFFLUENCE TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
S OF 28N BETWEEN 64W-78W. WEAK UPPER LEVEL TROUGH EXTENDS FROM
AN UPPER LOW NEAR 31N62W SW TO 27N63W WITH A WEAK 1013 MB
SURFACE LOW TO THE E NEAR 29N55W AND A SURFACE TROUGH EXTENDING
SW TO 26N60W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM
27N-32N BETWEEN 50W-55W. BROAD UPPER HIGH IS IN THE W TROPICAL
ATLC NEAR 15N55W COVERING THE AREA FROM 40W ACROSS THE LESSER
ANTILLES INTO THE FAR E CARIBBEAN. UPPER DIFFLUENCE AND AN
ABUNDANCE OF TROPICAL MOISTURE ARE GENERATING SCATTERED SHOWERS
AND WIDELY ISOLATED THUNDERSTORMS FROM 9N-17N W OF 51W TO ACROSS
THE LESSER ANTILLES. AN UPPER TROUGH COVERS THE E ATLC EXTENDING
FROM AN UPPER LOW JUST N OF THE CANARY ISLANDS NEAR 31N16W INTO
THE E TROPICAL ATLC ACROSS THE CAPE VERDE ISLANDS THEN SW TO
NEAR 10N34W AND COVERS THE REMAINDER OF THE ATLC. A SMALL
SURFACE 1012 MB LOW HAS FORMED BENEATH THIS UPPER LOW NEAR
32N16W WITH SCATTERED SHOWERS WITHIN 120/150 NM OF THE SURFACE
LOW. A SURFACE RIDGE COVERS THE REMAINDER OF THE E ATLC INTO THE
CENTRAL ATLC EXTENDING FROM A HIGH WELL N OF THE REGION THROUGH
32N28W SW TO NEAR 20N56W.

$$
WALLACE


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