[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN DEC 11 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 11N12W 7N20W 4N30W 5N40W 4N50W 5N59W. WIDELY SCATTERED TO
SCATTERED MODERATE SHOWERS AND ISOLATED STRONG THUNDERSTORMS ARE
FOUND FROM 1N TO 8N BETWEEN THE PRIME MERIDIAN AND 3W...FROM 5N
TO 8N BETWEEN 13W AND 18W...AND FROM 5N TO 7N BETWEEN 22W AND
28W. UPPER LEVEL SOUTHWESTERLY WIND FLOW IS PUSHING HIGH CLOUDS
NORTHEASTWARD. THESE CLOUDS ARE SOUTH OF 19N10W 19N16W 12N31W.
LOW CLOUDS AND ISOLATED MODERATE SHOWERS ARE FOUND FROM 6N TO
12N BETWEEN 45W AND 60W...MOVING SOUTHWESTWARD AND REACHING
THE COASTS OF GUYANA AND VENEZUELA.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH HAS SWEPT INTO THE NORTHERN HALF
OF THE GULF OF MEXICO FROM THE U.S.A. CENTRAL PLAINS...PUSHING
WITH IT A DEVELOPING COLD FRONT AT THE SURFACE. THIS COLD FRONT
NOW PASSES THROUGH 31N79W IN THE ATLANTIC OCEAN TO NORTH FLORIDA
NEAR 29N82W TO THE NORTH CENTRAL GULF NEAR 27N90W TO THE DEEP
SOUTH TEXAS AND A SMALL PART OF NORTHERN MEXICO NEAR 27N100W.
BROKEN TO OVERCAST MULTILAYERED CLOUDS COVER MOST OF THE GULF
WATERS...LEAVING ONLY A BIT OF THE SOUTHEASTERN CORNER...THE
EASTERN HALF OF THE SOUTHWESTERN CORNER SOUTH OF 21N EAST OF
93W...AND THE NORTHWESTERN CORNER WITH FAIR SKIES. A DISSIPATING
STATIONARY FRONT ALSO IS SQUEEZED INTO THE GULF...RUNNING FROM
LAKE OKEECHOBEE TO THE SOUTH CENTRAL GULF WATERS TO A 1015 MB
LOW PRESSURE CENTER NEAR 23N94W. A TROUGH RUNS FROM THIS LOW
CENTER TO MEXICO JUST EAST OF THE ISTHMUS OF TEHUANTEPEC.
ISOLATED AMOUNTS OF PRECIPITATION HAVE DEVELOPED...AND POSSIBLY
DISSIPATED BY NOW...FROM 22N TO 26N BETWEEN 84W AND 93W.

THE CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL RIDGE RUNS FROM 15N65W INTO THE ATLANTIC
OCEAN BEYOND 33N60W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG
THUNDERSTORMS ARE FOUND FROM 10N TO 16N BETWEEN 77W AND 84W IN AN
AREA OF AT LEAST 20 KT QUIKSCAT WINDS...FROM 11/1100 UTC...SURFACE
ONSHORE FLOW...AND COMPARATIVELY TIGHTER PRESSURE GRADIENT.
MIDDLE TO UPPER LEVEL DRY AIR ABOUNDS EVERYWHERE ELSE IN THE
CARIBBEAN WATERS. THE 11/1500 UTC CIMSS SATELLITE DERIVED WIND DATA
SHOW UPPER LEVEL SOUTHWESTERLY WIND FLOW WITH THE RIDGE IN THE AREA
WEST OF 75W NORTH OF 15N AND MIDDLE LEVEL ANTICYCLONIC WIND FLOW
BETWEEN 60W AND 70W.

THE ATLANTIC OCEAN...
THE LARGE SCALE PATTERN IS TROUGH IN THE GULF OF MEXICO...FOLLOWED
BY A RIDGE FROM THE CARIBBEAN SEA INTO THE WESTERN ATLANTIC OCEAN...
FOLLOWED BY THE DEEP LAYERED TROUGH IN THE EASTERN ATLANTIC OCEAN.
THE ATLANTIC RIDGE-TO-TROUGH SCENARIO HAS BEEN THE SAME FOR THE LAST
FEW DAYS. THE ANTICYCLONIC FLOW FROM THE MIDDLE TO UPPER LEVEL RIDGE
COVERS THE ATLANTIC OCEAN AND THE CARIBBEAN SEA NORTH OF 10N WEST OF
50W...WITH THE AREA NORTH OF 20N BETWEEN 40W AND 50W AS THE
TRANSITION AREA ON THE EASTERN SIDE OF THE RIDGE WITH THE FLOW GOING
TOWARD THE TROUGH. THE EASTERN ATLANTIC DEEP LAYER TROUGH SUPPORTS
THE 995 MB GALE CENTER NEAR 31N29W. A COLD FRONT CURVES EASTWARD
FROM THIS LOW CENTER TO 30N22W...TO 23N22W AND TO 16N31W. WIDELY
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE
FOUND FROM 26N TO 31N BETWEEN 17W AND 20W. OTHER CLOUDS HAVE
DEVELOPED DURING THE LAST SIX HOURS FROM 22N TO 28N BETWEEN 20W
AND 33W IN THE CYCLONIC FLOW.

$$
MT


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