[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 012357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU DEC 01 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM EPSILON AT 01/2100 UTC IS NEAR
31.7N 51.0W OR ABOUT 1425 MILES/2290 KM W OF THE AZORES ISLANDS.
EPSILON IS MOVING NE 9 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 991 MB. THE MAXIMUM SUSTAINED WINDS ARE 60 KT WITH
GUSTS TO 75 KT. PLEASE REFER TO THE LATEST NHC FORECAST/ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC
ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS.  AN
EYE-LIKE FEATURE HAS PERSISTED WITH EPSILON AND A LITTLE MORE
INTENSIFICATION APPEARS TO HAVE TAKEN PLACE.  HOWEVER CONVECTION
HAS BECOME MORE SHALLOW AND LESS ORGANIZED DURING THE PAST FEW
HOURS WITH ONLY ISOLATED MODERATE CONVECTION AROUND THE CENTER.
ISOLATED MODERATE CONVECTION IS ALSO FROM 28N-32N BETWEEN
40W-50W.  A GRADUAL WEAKENING SEEMS LIKELY AS WATER TEMPERATURES
SLOWLY COOL AND VERTICAL WIND SHEAR INCREASES.

...ITCZ...

ITCZ AXIS IS ALONG 7N11W 5N37W 8N50W 5N55W.  SCATTERED MODERATE
CONVECTION IS WITHIN 75/90 NM OF A LINE FROM 4N37W 7.5N48W
7.5N55W THEN SW INTO SURINAME NEAR 5N55W.

...DISCUSSION...

GULF OF MEXICO...
HIGH PRESSURE DOMINATES A GOOD PORTION OF THE AREA WITH A 1022
MB HIGH NEAR 27.5N88.5W BRINGING MOSTLY CLEAR CONDITIONS E OF
90W.  A WEAK COLD FRONT IS MAKING ITS WAY THRU THE NW GULF...
FROM ABOUT LAFAYETTE LOUISIANA TO 27.5N93W THEN INTO S TEXAS A
LITTLE N OF BROWNSVILLE.  BROKEN LOW CLOUDS AND ISOLATED SHOWERS
ARE N OF 26.5N W OF 90.5W ASSOCIATED WITH THE FRONT.  THE GULF
PORTION OF THE FRONT WILL LIKELY STALL OVERNIGHT WITH WHATEVER
IS LEFT OF THE BOUNDARY MOVING NORTHWARD NEAR LOUISIANA
OVERNIGHT SAT.  A FEW SHOWERS/TSTMS ARE IN THE SW GULF WITHIN 60
NM OF 21N95.5W ASSOCIATED WITH SOME RESIDUAL MOISTURE AND A WEAK
COASTAL TROUGH ALONG E MEXICO.  MOST OF THE SIGNIFICANT MOISTURE
SHOULD REMAIN FAR INTO THE SW GULF AND BAY OF CAMPECHE OVER THE
WEEKEND... WITH ANOTHER COLD FRONT LURKING N OF THE AREA
PROBABLY UNTIL LATE SUN.  IN THE UPPER LEVELS... DRY ZONAL FLOW
DOMINATES AT THE SOUTHERN END OF A FLATTENING E COAST TROUGH.

CARIBBEAN SEA...
WEAK MID/UPPER RIDGING IS IN THE SW CARIBBEAN... WITH WINTERTIME
ZONAL FLOW COVERING THE REST OF THE AREA.  IN ADDITION
MODERATE/STRONG SUBSIDENCE IS ALSO PUTTING A LID ON CONVECTION
OUTSIDE OF A WEAK FRONT IN THE NW CARIBBEAN FROM 21N80W TO THE
GULF OF HONDURAS.  ISOLATED MODERATE CONVECTION IS N OF 16N W OF
84.5W BEHIND THE FRONT.  OTHERWISE CONDITIONS ARE RATHER
TRANQUIL WITH DEWPOINTS REMAINING BELOW 70F IN THE FAR NE
CARIBBEAN AND ONLY A FEW CLUSTERS OF TRADEWIND CUMULUS PRODUCING
SHOWERS.  THINGS WILL BE SLOWLY CHANGING BY THE WEEKEND.. SUCH
THAT THE CHANCE OF RAIN SHOULD INCREASE OVER THE SOUTHERN
WINDWARD ISLANDS WITH A NEARBY UPPER TROUGH... OVERSPREADING THE
REST OF THE WINDWARDS BY LATE SUN POSSIBLY AS FAR N AS
GUADELOUPE BY MON.

ATLANTIC OCEAN...
COLD FRONT IS IN THE W ATLC FROM 32N70W TO THE NW BAHAMAS INTO
CENTRAL CUBA NEAR 22.5N79W.  UPPER SUPPORT FOR TSTMS IS LACKING
EXCEPT AT THE NORTHERN END WITH ISOLATED TSTMS WITHIN 45 NM OF
THE FRONT N OF 28N.  FAIR SKIES ARE E OF THE FRONT TO THE LARGE
CIRCULATION OF EPSILON... WHERE CLOUDS INCREASE E OF 55W AND
SHOWERS/TSTMS BECOME MORE NUMEROUS TO THE SE OF THE CYCLONE.
THE CULPRIT IS THE LARGE UPPER TROUGH STUCK OVER THE CENTRAL
ATLC... WITH A SHORTWAVE NEAR 31N42W CAUSING A LARGE AREA OF
SCATTERED SHOWERS/TSTMS FROM 24N-31N BETWEEN 32W-40W.  THIS AREA
MIGHT FORM INTO A LOW PRESSURE AREA OVER THE WEEKEND... BUT MOST
MODELS SUGGEST IT WON'T BE AS TROPICAL AS THE LAST TWO LOWS OUT
THERE (DELTA AND EPSILON) WITH COOLER WATER TEMPERATURES THAN A
COUPLE WEEKS AGO AND MARGINAL UPPER-AIR CONDITIONS.    MORE
ISOLATED TSTM ACTIVITY IS FROM 18N-24N BETWEEN 34W-46W.
SHORTWAVE RIDGING IS TO THE W OF THE CENTRAL ATLC TROUGH WITH
LARGER-SCALE RIDGING PERSISTING IN THE E ATLC FROM TROUGHING
NEAR 6N38W TO 30N26W.  VERY DIVERGENT PATTERN ALOFT ON THE W
SIDE OF THE RIDGE IS SUPPORTING A LARGE AREA OF ITCZ TSTMS.

$$
BLAKE


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