[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 231758
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON OCT 23 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 30W S OF 16N MOVING W NEAR 15 KT. THIS
MORNINGS VISIBLE IMAGERY DEPICTS CLEAR CYCLONIC TURNING/INVERTED
V PATTERN IN THE LOW TO MID CLOUD FIELD ABOUT THE WAVE AXIS.
DEEP CONVECTION IS MINIMAL EXCEPT FOR THE SCATTERED MODERATE
CONVECTION EMBEDDED WITHIN THE ITCZ FROM 6N-11N WITHIN 200NM OF
EITHER SIDE OF THE AXIS.

TROPICAL WAVE IS ALONG 52W/53W S OF 18N MOVING W 10-15 KT.
NARROW AREA OF CYCLONIC TURNING NOTED ABOUT THE AXIS WITHIN
51W-55W. DEEP CONVECTION IS MINIMAL ASIDE FROM A FEW ISOLATED
SHOWERS/TSTMS FROM 12N-17N BETWEEN 52W-56W.

A TROPICAL WAVE WILL LIKELY BE ADDED TO THE 1800 UTC MAP S OF
HISPANIOLA DUE TO THE INVERTED V PATTERN NOTED IN VISIBLE
IMAGERY...THOUGH CONVECTION IS MINIMAL WITH THIS FEATURE.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 8N21W 10N33W 12N50W TO THE
SOUTH AMERICAN COAST NEAR 9N61W. MINIMAL DEEP CONVECTION NOTED
WITHIN 200NM OF THE AXIS FROM THE COAST OF AFRICA TO 25W.
SCATTERED SHOWERS/TSTMS NOTED FROM 8N-11N BETWEEN 25W-28W.
CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
SEEN IN THE AREA FROM 4N-12N BETWEEN 33W-49W...AND A LOW
AMPLITUDE TROPICAL WAVE MAY BE EMBEDDED IN THIS REGION NEAR 46W
BASED ON LAST NIGHTS QUIKSCAT PASS AND ANALYSIS OF HOVMOLLER
DIAGRAMS. THUS...THIS FEATURE MAY ALSO BE ADDED TO THE 1800 UTC
MAP.

...DISCUSSION...
GULF OF MEXICO...
MAIN FEATURE IN THE GULF IS THE SURFACE COLD FRONT EXTENDING W
ACROSS THE CENTRAL PORTION FROM NEAR BRADENTON FLORIDA ALONG
27N83W 24N93W...AND THEN EXTENDS SW AS A STATIONARY FRONT TO
20N97W THEN INLAND OVER ERN MEXICO. DEWPOINTS ARE GENERALLY
FALLING INTO THE 40S-60S N OF THE FRONT AND REMAIN IN THE 70S S
OF THE FRONT. TEMPERATURE GRADIENT ALSO QUITE EVIDENT WITH
50S/60S NOW IN NORTHERN FLORIDA AND GULF COAST REGION WITH
70S/80S TO THE S AT 1500 UTC. OVERALL DEEP CONVECTION IS MINIMAL
NEAR THE FRONT THOUGH A FEW ISOLATED SHOWERS/TSTMS IN THE SW
GULF FROM 18N-26N BETWEEN 91W-98W. A 1027 MB SURFACE HIGH
PRESSURE AREA IS BUILDING INTO THE NRN GULF BEHIND THE FRONT
FROM ITS CENTER OVER CENTRAL TEXAS. THE COLD FRONT WILL CONTINUE
PUSHING SE THROUGH FLORIDA AND THE SE GULF OVER THE NEXT 24HRS
BRINGING PLEASANT WEATHER TO THE AREA. N/NE FLOW AND ASSOCIATED
SHORT PERIOD WIND WAVES WILL ALSO STEADILY INCREASE...SEE
MIAOFFNT4 FOR DETAILS. ALOFT...WLY FLOW DOMINATING MUCH OF THE
GULF BETWEEN THE UPPER HIGH OVER SE MEXICO AND THE DEEP LAYER
TROUGH OVER THE ERN THIRD OF THE COUNTRY.

CARIBBEAN SEA...
AN UPPER LOW REMAINS OVER THE NW CARIBBEAN NEAR 18N83W. THERE IS
A WEAK REFLECTION OF THIS AT THE SURFACE AS A TROUGH EXTENDING
NNE FROM COASTAL HONDURAS ALONG 14N85W 18N83W. SHOWER/TSTM
ACTIVITY IN THE VICINITY IS MINIMAL. THIS TROUGH EXPECTED TO
DISSIPATE THROUGH TOMORROW AS COLD FRONT ENTERS THE AREA FROM
THE NW. THE REMAINDER OF THE CARIBBEAN IS DOMINATED BY THE
ANTICYCLONIC UPPER FLOW AROUND THE UPPER HIGH JUST N OF PUERTO
RICO NEAR 20N67W. THE NEW WAVE TO BE ADDED S OF HISPANIOLA IS
HELPING TO ENHANCE THE ISOLATED SHOWERS WITH EMBEDDED TSTMS SEEN
FROM 14N-20N BETWEEN 68W-73W. THE ITCZ IS HELPING TO ENHANCE
CLUSTERS OF SCATTERED MODERATE CONVECTION IN THE FAR SE
CARIBBEAN NEAR NW TRINIDAD...AND IN THE SRN CARIBBEAN JUST W OF
THE COLOMBIAN COAST.

ATLANTIC OCEAN...
WRN ATLC DOMINATED BY SURFACE COLD FRONT PUSHING THROUGH THE
AREA ASSOCIATED WITH LARGE DEEP LAYER TROUGHING OVER THE ERN
THIRD OF THE COUNTRY. THIS WILL USHER IN SOME OF THE COOLEST AIR
OF THE SEASON THUS FAR...ALONG WITH INCREASING N FLOW AND STEEP
SHORT PERIOD WIND WAVES THROUGH TOMORROW. SEE STATEMENTS FROM
LOCAL WEATHER SERVICE OFFICES AND MIAOFFNT3 FOR MORE DETAILS.
PREFRONTAL TROUGH ANALYZED ALONG 24N81W 29N78W. BROAD UPPER
RIDGING DOMINATES THE AREA BETWEEN 55W-75W WITH AN ASSOCIATED
UPPER HIGH N OF PUERTO RICO NEAR 20N67W. A MINOR UPPER LOW
EMBEDDED IN THIS FEATURE NEAR 23N60W...WITH A DISSIPATING 1012MB
SFC LOW NEAR 25N65W THAT HAS NO ASSOCIATED DEEP CONVECTION. THE
UPPER LEVEL ENVIRONMENT IN THE REST OF THE CENTRAL AND ERN ATLC
DOMINATED BY A PAIR OF UPPER LOWS NEAR 20N49W AND 21N32W...AND
AN UPPER HIGH S OF THIS AREA NEAR 12N37W. THE SURFACE PATTERN IN
THIS REGION IS DOMINATED BY A TRIAD OF WEAK HIGH PRESSURE
CENTERS AT 30N59W...25N51W...AND 23N31W. A SURFACE TROUGH EXISTS
WITH THE CONFLUENCE BETWEEN THE LATTER TWO ALONG 19N48W
26N41W...AND SHOULD REMAIN QUASI STATIONARY THROUGH TOMORROW.
ISOLATED SHOWERS NOTED WITHIN 100NM OF THIS TROUGH AXIS.

$$
WILLIS




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