[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 051738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN NOV 04 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 IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 44W S OF 18N MOVING W NEAR 10 KT. THIS
WAVE HAS BECOME MUCH LESS ORGANIZED TODAY WITH NEARLY ALL OF THE
DEEP MOISTURE DISPLACED WELL TO THE NE OF THE WAVE. THIS IS DUE
TO VERY UNFAVORABLE STRONG SWLY UPPER LEVEL WINDS ASSOCIATED
WITH A SHARP TROUGH IN THE CENTRAL/EASTERN ATLC. THE ONLY
FEATURE DEFINING THE WAVE AXIS IS LOW TO MID LEVEL CYCLONIC
TURNING...WHICH HAS BECOME EASIER TO SEE ON VIS IMAGES SINCE ALL
OF THE DEEP LAYERED CLOUDS HAVE BEEN SHEARED OFF.

A TROPICAL WAVE IS IN THE WRN CARIBBEAN ALONG 88W S OF 17N
MOVING W 10 KT. THIS WAVE IS MAINLY IN THE EPAC EXCEPT FOR THE
NRN EXTENSION WHICH STRETCHES ACROSS HONDURAS. LITTLE SIGNATURE
IS EVIDENT AND THERE IS NO DEEP CONVECTION ASSOCIATED WITH THIS
WAVE. THEREFORE...THE PSN IS BASED MOSTLY ON EXTRAPOLATION.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N14W 12N33W 10N43W 6N55W.
SCATTERED MODERATE CONVECTION IS FROM 5N-12N BETWEEN 23W-30W.
SIMILAR CONVECTION IS WITHIN 240 NM N OF THE AXIS BETWEEN
33W-40W ASSOCIATED WITH THE TROPICAL WAVE ALONG 44W.

...DISCUSSION...
THE GULF OF MEXICO...
STRONG SFC HIGH PRES CENTERED ACROSS THE MID-ATLANTIC/NORTHEAST
CONTROLS THE WEATHER FOR MOST OF THE GULF PRODUCING MAINLY FAIR
AND QUITE WINDY CONDITIONS. THE STRONGEST WINDS ARE IN THE E
GULF WHERE SEVERAL SHIPS/BUOYS ARE REPORTING NE TO E WINDS
BETWEEN 20 AND 30 KT. THESE WINDS ARE PRODUCING SEAS TO 11 FT.
FOR DETAILS REFER TO THE OFFSHORE WATERS FORECAST FOR THE GULF
OF MEXICO...MIAOFFNT4. A SFC TROUGH HAS DEVELOPED IN THE CNTRL
GULF ANALYZED FROM 23N87W TO 27N91W. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE FROM 24N-27N BETWEEN 87W-91W. SFC WINDS MAY
ALSO BE SLIGHTLY STRONGER NEAR THE TROUGH AS THE PRES GRAD IS
TIGHTENED A LITTLE. THE UPPER LEVEL FLOW IS NEARLY ZONAL WITH
MODERATE DRY AIR ALOFT OVER THE ERN GULF AND CENTRAL/NORTHERN
FLORIDA. THE STRONG SFC RIDGE WILL CONTINUE TO SLOWLY SLIDE
EWARD AS A COLD FRONT ENTERS THE WRN GULF TOMORROW NIGHT OR TUES
MORNING.

THE CARIBBEAN SEA...
A BROKEN PLUME OF MOISTURE REMAINS IS IN THE WRN CARIBBEAN W OF
A LINE FROM ERN CUBA TO NICARAGUA. THIS MOISTURE CONTINUES TO
THIN OUT AS VERY DRY AIR IN THE CENTRAL AND ERN CARIBBEAN IS
ADVECTED W. THIS REMNANT MOISTURE IS NOW MAINLY ASSOCIATED WITH
SWLY UPPER LEVEL FLOW...ON THE WRN PERIPHERY OF AN UPPER HIGH
CENTERED S OF HISPANIOLA NEAR 16N71W. THE REMAINDER OF THE
CARIBBEAN IS QUIET WITH PLENTY OF DRY STABLE AIR ALOFT ACROSS
THE AREA SUPPRESSING SIGNIFICANT SHOWER ACTIVITY. TRADE WINDS
REMAIN MODERATE WITH TYPICAL LOW-LEVEL MOISTURE STREAMS STEERED
W BY THE FLOW. STRONGER WINDS...20 TO 25 KT...ARE IN THE YUCATAN
CHANNEL WHERE THE PRES GRAD IS TIGHTER DUE TO STRONG HIGH PRES
TO THE N.

THE ATLANTIC OCEAN...
A HIGH AMPLITUDE UPPER LEVEL PATTERN IS ESTABLISHED ACROSS THE
ATLC BASIN...ESPECIALLY IN THE CENTRAL AND ERN ATLC. STRONG
W-SWLY UPPER LEVEL FLOW...BETWEEN A PROGRESSIVELY FLATTENING
TROUGH OFF THE U.S. EAST COAST AND A HIGHLY ELONGATED UPPER
LEVEL RIDGE...IS ADVECTING SOME DEBRIS TROPICAL MOISTURE ACROSS
THE BAHAMAS INTO THE ATLC. MOST OF THE MOISTURE IS IN THE UPPER
LEVELS EXCEPT FOR SCATTERED SHOWERS AND TSTMS ACROSS ERN CUBA
AND THE SE BAHAMAS. AN ASSOCIATED COLD FRONT EXTENDS FROM A 1015
MB LOW NEAR 33N54W ALONG 26N61W TO NEAR THE COAST OF HISPANIOLA.
SHOWERS AND TSTMS ARE WITHIN 120 NM AHEAD OF THE FRONT N OF 26N.
THERE IS NOT MUCH CLEARING BEHIND THE FRONT AS SOME MID/UPPER
LEVEL MOISTURE IS LINGERING ASSOCIATED UPPER SWLY FLOW AS
MENTIONED ABOVE. MUCH DRIER AIR ALOFT IS W OF 68W N OF
27N...SLOWLY PRESSING ESE. A TIGHT SFC PRES GRAD BETWEEN STRONG
HIGH PRES IN THE ERN U.S. AND THE COLD FRONT IS GENERATING SWIFT
NE WINDS FROM 20 TO 30 KT BEHIND THE FRONT PRODUCING HIGH SEAS
IN NE SWELL. A STRONGLY ELONGATED UPPER RIDGE ORIGINATING IN THE
CARIBBEAN STRETCHES NEWARD ALONG 20N62W 32N44W.  THIS PATTERN
THEN FOLDS INTO A STRONG SHARP UPPER TROUGH THAT ENCOMPASSES
MUCH OF THE E ATLC. THE UPPER AXIS EXTENDS FROM AN UPPER LOW
JUST NE OF THE AZORES TO ANOTHER UPPER LOW NEAR 19N41W
CONTINUING TO 13N57W. VERY DRY STABLE UPPER LEVEL AIR LIES TO
THE W OF THE TROUGH AXIS TO 50W. A FAIR AMOUNT OF MOISTURE LIES
E OF THE AXIS TO NEAR THE COAST OF W AFRICA. SOME OF THIS
MOISTURE IS ASSOCIATED WITH THE TROPICAL WAVE ALONG
44W...HOWEVER THE STRONG W-SWLY UPPER WINDS IS SHEARING ALL OF
THE DEEP CONVECTION TO THE NE OF THE WAVE. A LARGE UPPER LEVEL
HIGH IS OFF THE COAST OF W AFRICA NEAR 12N20W. UPPER DIFFLUENCE
ON THE SW PERIPHERY OF THE HIGH IS ENHANCING CONVECTION IN THE
ITCZ BETWEEN 23W-30W.

$$
CANGIALOSI




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