[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE OCT 24 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 36W/37W S OF 18N MOVING W NEAR 15 KT.
INVERTED V PATTERN/CYCLONIC TURNING OF THE LOW CLOUD FIELD NOTED
ABOUT THE WAVE AXIS...UNDERNEATH THE HIGHER CLOUDS STREAMING
ANTICYCLONICALLY AROUND THE UPPER HIGH JUST TO THE W. SCATTERED
MODERATE CONVECTION FROM 9N-14N BETWEEN 34W-43W.

TROPICAL WAVE IS ALONG 58W...JUST E OF THE WINDWARD ISLANDS...S
OF 19N MOVING W 10-15 KT. BROAD CYCLONIC TURNING EVIDENT IN THE
LOW TO MID CLOUD FIELD...WITH NUMEROUS MODERATE/ISOLATED STRONG
CONVECTION FROM 12N-18N BETWEEN 54W-61W.

TROPICAL WAVE IS ALONG 75W/76W S OF 19N DRIFTING SLOWLY TO THE
W.  IT APPEARS THIS WAVE IS SLOWING AND BECOMING TILTED FROM SE
TO NW...AND MAY BECOME EVEN MORE DIFFICULT TO TRACK AS IT
INTERACTS WITH THE APPROACHING FRONTAL SYSTEM FROM THE NW. DEEP
CONVECTION IS MINIMAL WITH A FEW ISOLATED SHOWERS/TSTMS NOTED
WITHIN 100NM OF THE AXIS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N13W 8N24W 11N35W 10N48W 14N55W TO
INLAND OVER THE S AMERICAN COAST NEAR 10N62W. NARROW BAND OF
SCATTERED MODERATE CONVECTION WITHIN 100NM OF THE LINE ALONG
5N13W 4N22W 9N31W. SCATTERED SHOWERS/TSTMS FROM 7N-15N BETWEEN
45W-55W.

...DISCUSSION...
GULF OF MEXICO...
MUCH OF THE GULF IS EXPERIENCING COOL FALL WEATHER THIS
AFTERNOON IN WAKE OF THE RECENT COLD FRONT PASSAGE. THE TAIL END
OF THE FRONTAL BOUNDARY IS PRODUCING SCATTERED SHOWERS/TSTMS IN
THE BAY OF CAMPECHE FROM 19N-23N BETWEEN 92W-97W. UPPER HIGH
PRESSURE OVER THIS AREA IS ALSO SUPPORTING THIS ACTIVITY.
ELSEWHERE IN THE UPPER LEVELS...VERY DRY AIR MOVING OVER THE NE
GULF AND FLORIDA AROUND THE LARGE TROF PUSHING OFF THE EAST
COAST. SURFACE HIGH PRESSURE N OF THE AREA IS PRODUCING 15-25KT
N/NE WINDS FOR THE ERN GULF WITH MORE OF AN E FLOW IN THE WRN
GULF. ASSOCIATED SHORT TO MEDIUM PERIOD WIND WAVES HAVE ALSO
BUILT...LARGEST S AND W PORTIONS AT THE TAIL END OF THE FETCH.
WINDS AND SEAS WILL GRADUALLY VEER IN DIRECTION AND SLOWLY RELAX
OVER THE NEXT COUPLE OF DAYS WITH THE HIGH MOVING EAST NORTH OF
THE AREA...SEE MIAOFFNT4 FOR DETAILS.

CARIBBEAN SEA...
AN UPPER LOW REMAINS OVER THE NW CARIBBEAN NEAR 18N82W. THERE IS
A WEAK REFLECTION OF THIS AT THE SURFACE AS A TROUGH EXTENDING
NNE FROM COASTAL HONDURAS ALONG 14N85W 19N82W. SHOWER/TSTM
ACTIVITY IN THE VICINITY IS OVERALL MINIMAL ASIDE FROM A FEW
ISOLATED CELLS FROM 19N-21N BETWEEN 82W-87W. HOWEVER...THIS MAY
BE MORE ASSOCIATED WITH PREFRONTAL LIFT AHEAD OF THE COLD FRONT
NOW EXTENDING THROUGH CENTRAL CUBA TO THE YUCATAN. THIS FRONT
WILL SLOW AND BEGIN TO DRIFT SE OVER THE NW WATERS DISSIPATING
THROUGH THU. A FEW CLUSTERS OF SCATTERED MODERATE CONVECTION
NOTED IN THE SW CARIBBEAN AND COASTAL PANAMA FROM 9N-13N BETWEEN
76W-82W...LIKELY ASSOCIATED WITH THE ITCZ AND WEAK UPPER
DIFFLUENCE. LARGE SCALE...BROAD UPPER RIDGING DOMINATES THE
CARIBBEAN BETWEEN 59W-78W. A FEW OTHER SMALL SCALE UPPER
FEATURES EMBEDDED IN THIS REGION BUT GENERATING LITTLE IF ANY
SIGNIFICANT WEATHER. THE TROPICAL WAVE JUST E OF THE WINDWARD
ISLANDS IS EXPERIENCING WLY SHEAR S OF AN UPPER LOW...AND WILL
MOVE THROUGH THE ERN CARIBBEAN THROUGH THE SECOND HALF OF THE
WORKWEEK.

ATLANTIC OCEAN...
WRN ATLC DOMINATED BY STRONG SURFACE COLD FRONT PUSHING THROUGH
THE AREA ASSOCIATED WITH LARGE DEEP LAYER TROUGHING PUSHING OFF
THE EAST COAST. THIS HAS USHERED IN SOME OF THE COOLEST AIR
OF THE SEASON THUS FAR...ALONG WITH INCREASING N/NW FLOW AND
RISING SHORT TO MEDIUM PERIOD SWELL. ASSOCIATED SWELL WILL
SPREAD E THROUGH THE CARIBBEAN THROUGH THE END OF THE WORKWEEK
BRINGING THE FIRST APPRECIABLE WINTER-LIKE SWELL EVENT OF THE
SEASON...SEE STATEMENTS FROM LOCAL WEATHER SERVICE OFFICES AND
MIAOFFNT3 FOR MORE DETAILS. PREFRONTAL TROUGH ANALYZED ALONG
21N70W 28N67W AND HAS A MORE PRONOUNCED CONFLUENT ZONE WITH IT.
ASSOCIATED SCATTERED MODERATE CONVECTION FROM 22N-30N BETWEEN
62W-67W...AND MOVING FAIRLY QUICKLY TO THE E. UPPER TROUGHING
NOTED FROM 15N-25N BETWEEN 45W-60W...HAS A WELL DEFINED UPPER
LOW CENTER NEAR 21N50W. CONVECTION IN THIS REGION IS MINIMAL
ASIDE FROM THAT DESCRIBED WITH THE TROPICAL WAVE JUST E OF
THE WINDWARD ISLANDS. AN UPPER HIGH NEAR 28N43W IS SURROUNDED BY
VERY DRY AIR...AND ALSO HAS A 1019MB SURFACE HIGH NEARBY AT
28N48W. ANOTHER UPPER HIGH NOTED FURTHER S NEAR 13N40W. UPPER
LOW SEEN SPINNING NEAR 19N28W WITH THE ASSOCIATED MOISTURE
LIMITED TO 200NM E OF THE ASSOCIATED UPPER TROUGH AXIS. ERN ATLC
ALSO DOMINATED BY A 1018MB SURFACE HIGH NEAR 22N28W THAT LOOKS
TO DISSIPATE AS THE SURFACE HIGH FURTHER NW NEAR 28N48W TAKES
OVER. THUS...THE TROUGH ANALYZED BETWEEN THESE TWO SFC HIGHS ALSO
LIKELY TO DISSIPATE.

$$
WILLIS




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