[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121126
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN NOV 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 60W S OF 14N MOVING W 10 TO 15 KT. THIS
WAVE HAS BECOME A WEAK LOW AMPLITUDE FEATURE AFTER PERSISTENT
STRONG WLY UPPER LEVEL WINDS AND WIDESPREAD STRONG SUBSIDENCE
HAVE TAKEN ITS TOLL. ONLY ISOLATED SHOWERS ARE ASSOCIATED WITH
THIS WAVE AND IT WILL LIKELY CONTINUE TO TRACK W AS A SHALLOW
FEATURE.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 5N31W 7N46W 10N57W 8N62W.
SCATTERED MODERATE CONVECTION IS FROM 4N-7N BETWEEN 23W-32W.
ISOLATED MODERATE IS E OF 15W FROM 5N-7N.

...DISCUSSION...
GULF OF MEXICO...
A MODERATE COLD FRONT IS TRACKING ACROSS THE AREA...AS OF 09Z IT
WAS ANALYZED FROM N CENTRAL FL TO 24N87W CONTINUING TO THE COAST
OF S MEXICO NEAR 18N94W. THE FRONT IS THEN HUNG UP ALONG THE E
SLOPES OF THE SIERRA MADRE IN MEXICO. N-NE WINDS FROM 15 TO 25
KT ARE COMMON BEHIND THE FRONT AS STRONG HIGH PRES HAS BUILT SWD
INTO THE MID-WEST. TEMPS AND DEWPOINTS HAVE ALSO DROPPED
NOTICEABLY...FROM THE 60'S AND LOW 70'S ACROSS CENTRAL AND SOUTH
FLORIDA TO DEWPOINTS AND TEMPS FALLING INTO THE 40'S AND LOW
50'S BEHIND THE BOUNDARY IN THE FL PANHANDLE AND ACROSS THE GULF
COAST. THE FRONT IS NOT EASILY DEFINED USING NIGHT CHANNEL VIS
IMAGES AS THERE IS A LOT OF UPPER-LEVEL MOISTURE MASKING ANY
LOW-LEVEL SIGNAL. THIS UPPER LEVEL MOISTURE IS WIDESPREAD ACROSS
THE GULF AS IT IS CONTINUOUSLY BEING ADVECTED FROM A LARGE MASS
OF UNSETTLED WEATHER IN THE EPAC ASSOCIATED WITH THE REMNANTS OF
ROSA AND SHORT-LIVED T.D. 20-E. SCATTERED SHOWERS ARE EMBEDDED
IN THIS MOISTURE PLUME N OF 24N W OF 88W. THE FRONT WILL
CONTINUE TO SLIDE SE AND WEAKEN OVER THE NEXT DAY OR TWO. THIS
WILL ALLOW SFC WINDS TO GRADUALLY SUBSIDE AND VEER E.

CARIBBEAN...
THE CARIB REMAINS QUIET THIS EARLY MORNING WITH PLENTY OF
DRY/STABLE SINKING AIR ALOFT IN PLACE. THE MID-UPPER LEVEL
PATTERN PRODUCING THIS STABLE ENVIRONMENT CONSISTS OF AN UPPER
RIDGE CENTERED IN THE WRN CARIB NEAR 17N83W AND SLIGHT RIDGING E
OF THE AREA IN THE TROPICAL ATLC. A WEAKNESS LIES ABOVE THE
CNTRL CARIB INDUCED BY A WEAKENING TROUGH TO THE N/NE. THE ONLY
AREA OF SIGNIFICANT WEATHER IS IN THE EXTREME SW CARIB WHERE
SCATTERED MODERATE CONVECTION IS S OF 11N BETWEEN 76W-82W
...ASSOCIATED WITH THE ITCZ. THERE ARE ALSO SCATTERED SHOWERS
AND TSTMS ACROSS PORTIONS OF NRN CENTRAL AMERICA ENHANCED BY
UPPER DIFFLUENCE AND ENHANCED LOW-LEVEL LIFT AHEAD OF THE COLD
FRONT IN THE GULF. OVERALL...LITTLE CHANGE IS EXPECTED OVER THE
NEXT FEW DAYS AS DRY AIR REMAINS ESTABLISHED ACROSS THE AREA.
TRADE WINDS ARE MODERATE AND WILL LIKELY REMAIN THAT WAY OR
SLACKEN SOME OVER THE NEXT FEW DAYS AS THE COLD FRONT IN THE
GULF...OR MORE LIKELY REMNANTS OF...STALL ACROSS THE NW PORTION
OF THE CARIB.

ATLANTIC OCEAN...
THE MID TO UPPER LEVEL PATTERN ACROSS THE SUBTROPICAL AND
TROPICAL ATLC HAS SIGNIFICANTLY FLATTENED. SLIGHT ELONGATED
RIDGING STRETCHES NWD FROM THE WRN CARIBBEAN ACROSS THE BAHAMAS
TOWARDS BERMUDA. A WEAKENING TROUGH LIES E OF THE RIDGE FROM A
CUT OFF NEAR 32N51W SOUTHWESTWARD TO THE MONA PASSAGE. THE CUT
OFF LOW IS VERTICALLY STACKED AND ANALYZED AT 1010 MB AT THE SFC
WITH A COLD FRONT ALONG 32N49W 24N53W 20N65W THEN STATIONARY TO
THE N COAST OF HISPANIOLA. ISOLATED SHOWERS ARE WITHIN 90 NM OF
THE FRONT. THE TRANSITION FROM AN UPPER TROUGH TO THIS STACKED
LOW WAS WELL FORECAST BY THE GFS YESTERDAY. THE UPPER LEVEL FLOW
BECOMES NEARLY ZONAL E OF 60W...WHICH IS A SIGNIFICANT CHANGE
FROM THE PAST FEW DAYS...AS THE LARGE CUT OFF LOW IN THE E ATLC
HAS PULLED N OF THE AREA NEAR 34N32W AND WEAKENED. A FAIR AMOUNT
OF MAINLY HIGH LEVEL MOISTURE LIES N OF 23N E OF 30W.
OTHERWISE...DRY AND STABLE AIR ALOFT COVERS MOST OF THE
REMAINDER OF THE ATLC N OF 13N KEEPING CONDITIONS QUIET. IN THE
DEEP TROPICS...THE ONCE PRONOUNCED UPPER-LEVEL JET THAT EXTENDS
FROM S AMERICA TO AFRICA HAS SUBSTANTIALLY WEAKENED BUT IS STILL
PRODUCING PATCHES OF SCATTERED SHOWERS FROM 9N-12N BETWEEN
33W-43W. GFS FORECASTS THE WEATHER PATTERN TO BECOME MORE
AMPLIFIED IN THE CENTRAL/WRN ATLC OVER THE NEXT COUPLE DAYS
WHILE STAYING RATHER ZONAL IN THE E ATLC.

$$
CANGIALOSI






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