[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE DEC 20 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 4N25W 1N40W 2N53W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 120 NM ON EITHER
SIDE OF THE AXIS FROM 14W-44W. MANY OF THE THUNDERSTORMS HAVE
BEEN WEAKENING OVER THE PAST 4 HOURS.

...DISCUSSION...

THE GULF OF MEXICO AND THE WESTERN ATLANTIC OCEAN WEST OF 60W...
A SURFACE RIDGE...ORIGINATING FROM A 1032 MB MIDWEST U.S.A.
HIGH CENTER...IS BRING FAIR WEATHER ACROSS TEXAS AND THE
CENTRAL AND WESTERN GULF OF MEXICO. THE CORE WINDS OF
A WEST-SOUTHWESTERLY JET STREAM...MAXIMUM WIND SPEEDS RANGING
FROM 90 KT TO 110 KT...STRETCH  FROM THE NORTH CENTRAL GULF
WATERS NORTHEASTWARD ACROSS NORTH FLORIDA...INTO THE ATLANTIC
OCEAN TO 33N71W...WHERE THE 20/1500 UTC CIMSS SATELLITE DERIVED
WIND DATA SHOW 130 KT WIND SPEEDS. UPPER LEVEL MOISTURE IS BEING
TRANSPORTED INTO THE GULF AREA FROM THE EASTERN PACIFIC OCEAN.
IN THE EASTERN GULF AND WESTERN ATLANTIC OCEAN A SURFACE COLD
FRONT EXTENDS FROM A STRONG 970 MB LOW PRESSURE SYSTEM WELL
NORTH OF THE AREA IN THE CENTRAL ATLANTIC NEAR 40N49W. THIS
FRONT EXTENDS FROM THE LOW TO 29N59W AND THEN FLATTENING ZONALLY
TO 27N73W. A WEAK LOW EXISTS AT THE BASE OF THE COLD FRONT IN
THE BAHAMAS NEAR 26N77W. A STATIONARY FRONT EXTENDS FROM THIS
LOW TO THE YUCATAN PENINSULA NEAR 17N88W. NEAR THE LOW IN THE
BAHAMAS AND ALONG AND NEAR THE FRONTAL BOUNDARIES THERE ARE
BROKEN TO OVERCAST SKIES WITH ISOLATED SHOWERS. THESE FEATURES
ARE SLOW MOVING SO CLOUDY CONDITIONS WITH ISOLATED SHOWERS ARE
EXPECTED IN THIS AREA FOR THE NEXT DAY OR SO.

THE CARIBBEAN SEA...
BROAD UPPER RIDGE CENTERED 100 NM MILES NORTH OF PUERTO RICO
COVERS THE CARIBBEAN SEA WITH STRONG SUBSIDENCE AND DRY UPPER
AIR DOMINATING ALL BUT THE YUCATAN CHANNEL N OF THE STATIONARY
FRONT THAT CROSSES CUBA NEAR 22N81W TO THE YUCATAN PENINSULA
NEAR 19N87W...WITH BROKEN/OVERCAST LOW/MID CLOUDS AND ISOLATED
SHOWERS. SURFACE EASTERLY TRADEWINDS COVER THE ENTIRE CARIBBEAN
SEA. PATCHY CLOUDS ARE DRIFTING NORTHWARD FROM 74W TO 83W NORTH
OF 12N. MOISTURE WILL REMAIN LIMITED ACROSS THE CARIBBEAN AS THE
UPPER HIGH REMAINS FAIRLY STATIONARY.

THE REMAINDER OF THE ATLANTIC OCEAN EAST OF 60W...
THE BROAD UPPER HIGH THAT IS SUPPLYING THE CARIBBEAN SEA WITH
DRY WEATHER ALSO IS ENHANCING FAIR WEATHER ACROSS MUCH OF THE
ATLANTIC WEST OF 50W SOUTH OF 25N. A 1024 MB SURFACE HIGH IS
LOCATED NEAR 31N36W. TO ITS EAST, AN OCCLUDED LOW PRESSURE
SYSTEM IS LOCATED NEAR 32N20W.  MODERATE SCATTERED SHOWERS ARE
MOST ORGANIZED FROM 250 NM TO 500 NM WELL TO THE EAST OF THE
LOW.  A JET STREAM WITH WINDS OF 100 KT TO 120 KT IS ALONG THE
NORTHERN PERIPHERY OF THE RIDGE EXTENDING ALONG 14N36W TO
A PEAK NEAR 28N10W. STRONG DIFFLUENCE...AIDED BY THE JET...
IS PRODUCING A LARGE AREA OF DENSE HIGH CLOUDS WITH SCATTERED
SHOWERS OVER THE AREA WITHIN 300 NM OF LINE FROM THE TROPICS
NEAR 10N34W 22N23W OVER AFRICA NEAR 27N13W INCLUDING THE CAPE
VERDE AND CANARY ISLANDS.

$$
JC/MT


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