[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 141802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU DEC 14 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...
METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...THE ITCZ...
ITCZ AXIS IS ALONG 7N11W 4N30W 4N40W EQ52W. ISOLATED CLUSTERS OF
MODERATE CONVECTION NOTED WITHIN 210 NM S OF THE AXIS BETWEEN
AFRICA AND 22W. SCATTERED MODERATE FROM 1N-7N BETWEEN 29W-30W.

...DISCUSSION...
THE GULF OF MEXICO...
A SFC TROUGH REMAINS NEARLY STATIONARY IN THE SRN GULF ALONG
86W/87W S OF 26N EXTENDING INTO THE NW CARIB. RATHER DISTINCT
LOW-LEVEL CYCLONIC TURNING IS NOTED IN SFC OBS...SATELLITE
IMAGES AND SAT LOW-LEVEL DERIVED WINDS MAKING THE AXIS OF THE
TROUGH EASY TO LOCATE. SCATTERED MODERATE CONVECTION IS E OF THE
AXIS FROM 23N-26N BETWEEN 83W-87W. SWIFT UPPER LEVEL WLY FLOW IS
SHEARING THIS ACTIVITY AND SPREADING DEBRIS SHOWERS ACROSS SOUTH
AND CENTRAL FLORIDA. STRONGER CELLS ALSO POPPING UP OVER SE
FLORIDA WITH A CLEAR WARM ADVECTION PROFILE AND LOW LEVEL JET
NOTED IN THE KMFL SOUNDING. THE UPPER LEVEL FLOW IS A RATHER
UNIFORM W-SWLY ACROSS THE GULF AHEAD OF AN APPROACHING SHORTWAVE
TROUGH LOCATED ABOVE TEXAS AND NRN MEXICO. A PLUME OF HIGH LEVEL
MOISTURE...ASSOCIATED WITH THE SUBTROPICAL JET ORIGINATING AT
THE BASE OF THE TROUGH...IS BEING ADVECTED FROM THE EPAC ACROSS
CENTRAL MEXICO AND INTO THE NRN GULF. THE SFC TROUGH APPEARS AS
IF IT MAY BE MERGING WITH THE STATIONARY FRONT EXTENDING THROUGH
THE FL BIG BEND AREA TO THE NE GULF. GUIDANCE SUGGESTS THE
ENTIRE FEATURE WILL MOVE E/SE THROUGH FL THROUGH EARLY
SAT...WITH WEAK HIGH PRESSURE FILLING IN ITS WAKE.

THE CARIBBEAN SEA...
ISOLATED CLUSTERS OF MODERATE CONVECTION NOTED IN THE FAR WRN
PORTION OF THE CARIBBEAN WHICH SEEM ASSOCIATED WITH SPEED
CONVERGENCE. THE TROUGH IN THE SW CARIBBEAN WAS REMOVED AS THERE
IS MUCH LESS CYCLONIC TURNING THAN NOTED 24 HOURS AGO. A PORTION
OF THE NW CARIBBEAN TROUGH THAT EXTENDS INTO THE GULF PERSISTS
AS DESCRIBED ABOVE. A WEAK UPPER RIDGE IS EXTENDING N THROUGH
80W WHILE AN UPPER TROUGH SURROUNDED BY DRY AIR EXTENDS THROUGH
THE FAR ERN CARIBBEAN. TRADE WINDS ARE MOSTLY IN THE 15-20 KT
RANGE AND LITTLE CHANGE IS EXPECTED THRU SAT AS SFC RIDGE
REMAINS TO THE NE OF THE REGION.

ATLANTIC...
AN UPPER RIDGE OVER THE SW NORTH ATLC IS ADVECTING DEBRIS
MOISTURE AND SHOWERS W TO E THROUGH THE AREA MAINLY W OF 70W.
THE STRONGEST CELLS NOTED OFF THE PALM BEACH FLORIDA
COAST...WHERE A WARM ADVECTION PROFILE IS COMPRISED OF LOW LEVEL
SE FLOW INTERACTING WITH THE UPPER WLY SHEAR. THE SFC PATTERN
OVER MUCH OF THE CENTRAL AND WRN ATLC AREA IS DOMINATED BY THE S
AND SW PORTION OF A 1034 MB SFC HIGH NEAR 38N52W. THIS HIGH
MOVES SLOWLY E TO SE THROUGH SAT AS THE STATIONARY FRONT
CURRENTLY OFF THE CAROLINAS BECOMES COLD AND PUSHES E TO SE TO
30N65W TO CENTRAL BAHAMAS LATE SAT. A PAIR OF WEAK SFC TROUGHS
ARE ON THE SRN PORTION OF THE CENTRAL ATLC HIGH BUT ARE NOT
GENERATING SIGNIFICANT WEATHER. THE FIRST EXTENDS JUST NORTH OF
THE DOMINICAN REPUBLIC TO 24N69W...THE OTHER IS ABOUT 500 NM E
OF THE WINDWARD ISLANDS ALONG 10N52W 17N51W. A PAIR OF UPPER
LOWS ALSO NOTED IN THE CENTRAL ATLC NEAR 20N57W AND 29N39W. THE
LATTER HAS AN ASSOCIATED 1011 MB SFC LOW NEAR 30N36W. A SHIP
REPORTED A 45 KT N WIND JUST NW OF THIS LOW AT 1200 UTC. A SFC
TROUGH EXTENDS S FROM THIS LOW 18N39W...BUT AT LEAST THE NRN
PART OF THIS WILL LIKELY BE CHANGED TO A COLD FRONT ON THE 1800
UTC MAP...WITH THE OPEN CELL CONVECTION NOTED TO ITS W. A SFC
RIDGE EXTENDS THROUGH THE FAR E ATLC PORTION FROM A 1034 MB
CENTER OVER NW SPAIN. ZONAL WLY FLOW PERSISTS OVER THE DEEP
TROPICS BETWEEN 10N-20N...AROUND AN ELONGATED UPPER HIGH JUST TO
ITS S.

$$
WILLIS




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