[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 170536
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT DEC 17 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N10W 8N30W 4N54W. SCATTERED
MODERATE CONVECTION WITHIN 90 NM OF THE AXIS BETWEEN 21W-28W.
WIDELY SCATTERED MODERATE WITHIN 120 NM OF THE AXIS BETWEEN
28W-37W. ISOLATED SHOWERS/TSTMS ELSEWHERE WITHIN 330 NM N OF THE
AXIS BETWEEN 33W-43W. SCATTERED MODERATE WITHIN 100 NM OF THE
COAST OF FRENCH GUIANA.

...DISCUSSION...

GULF OF MEXICO...
A STRONG MID/UPPER LEVEL TROUGH HAS DUG S OVER THE ROCKY
MOUNTAINS TO A MEAN POSITION ALONG 105W N OF 20N. THE
SUBTROPICAL JET RIDES ALONG THE E SIDE OF THE TROUGH FROM NE
MEXICO ALONG THE TEXAS COAST TOWARDS THE SRN APPALACHIANS WITH
CORE SPEEDS OVER 130 KT OVER THE OHIO VALLEY. THIS IS PRODUCING
MODERATE SWLY UPPER LEVEL FLOW OVER THE GULF WATERS WITH
MOISTURE LIMITED TO THE NW GULF NEAR THE JET. THE COLD FRONT
WHICH PUSHED THROUGH THE AREA OVER THE PAST COUPLE OF DAYS NOW
STRETCHES FROM THE STRAITS OF FLORIDA SW INTO THE BAY OF
CAMPECHE TO A 1011 MB LOW NEAR 21N95W. AN INVERTED SURFACE
TROUGH ALSO EXTENDS NW OF THE LOW TO NEAR BROWNSVILLE AND CORPUS
CHRISTI TEXAS...WITH STRONG 20-25 KT EASTERLY FLOW HAVING
DEVELOPED OVER THE N GULF. OVERCAST STRATUS WITH EMBEDDED
SHOWERS LIES N OF THE FRONT AND W OF THE LOW. THE FRONT IS
EXPECTED TO LIFT SLOWLY N AS A WARM FRONT OVER THE NEXT 24 HRS
WITH THE LOW MOVING NE ALONG THE FRONT INTO THE W ATLC. IT WILL
THEN BECOME STATIONARY AGAIN WITH A CHANCE OF SHOWERS OVER MUCH
OF THE AREA...INCLUDING FLORIDA...FOR THE NEXT SEVERAL DAYS.

CARIBBEAN...
A STRONG UPPER LEVEL ANTICYCLONE IS CENTERED NEAR ERN PANAMA AND
NW COLOMBIA WITH A RIDGE AXIS EXTENDING NWD TO THE WINDWARD
PASSAGE AND THEN NE INTO THE W ATLC. MODERATE/STRONG SUBSIDENCE
DOMINATES THE ENTIRE AREA BENEATH THE ANTICYCLONE. THE GREATEST
CONCENTRATION OF TRADE SHOWERS ARE LOCATED NEAR THE SRN WINDWARD
ISLANDS...OVER THE MOUNTAINS OF HISPANIOLA...AND MOVING ONSHORE
INTO NICARAGUA AND COSTA RICA. LITTLE CHANGE IS EXPECTED IN THE
OVERALL PATTERN EXCEPT THAT AN INCREASE IN MOISTURE OVER THE NW
CARIBBEAN BEGINNING SUN NIGHT COULD RAISE THE CHANCE FOR SHOWERS.

ATLANTIC...
A TILTED UPPER LEVEL RIDGE LIES OVER THE W ATLC EXTENDING FROM E
CUBA TO 32N57W WITH A VIGOROUS JET RIDING AROUND THE N SIDE OFF
THE U.S. MID-ATLC COAST. A COLD FRONT HAS MOVED INTO THE AREA
ALONG 32N71W SW ACROSS THE NRN BAHAMAS INTO THE STRAITS OF
FLORIDA...BUT STRONG SUBSIDENCE ASSOCIATED WITH THE UPPER RIDGE
HAS SUPPRESSED ANY DEEP CONVECTION. ONLY SCATTERED SHOWERS LIE
UP TO 150 NM E OF THE FLORIDA COAST. HIGH PRES IS IN CONTROL
OVER MUCH OF THE W/CNTRL ATLC FROM 32N60W TO THE SRN BAHAMAS
WITH SCATTERED/BROKEN STRATOCUMULUS COVERING THE AREA. FARTHER
E...A LARGE AND ELONGATED UPPER LOW IS LOCATED SW OF THE AZORES
NEAR 31N36W WITH A TROUGH EXTENDING SW TO THE LESSER ANTILLES.
THE SUBTROPICAL JET TO THE SE OF THE TROUGH EXTENDS FROM 16N53W
NE TO WESTERN SAHARA WITH CORE SPEEDS OVER 90 KT. THIS IS
PRODUCING A BROKEN BAND OF HIGH CIRRUS OVER THE TROPICS AND
SPREADING ACROSS THE CAPE VERDE ISLANDS TO W AFRICA. A 1010 MB
LOW IS CENTERED ABOUT 450 NM WSW OF THE CANARY ISLANDS NEAR
26N25W WITH A TROUGH EXTENDING NW TO 26N37W 30N43W. A CLUSTER OF
SCATTERED MODERATE CONVECTION HAS DEVELOPED NE OF THE LOW FROM
26N-29N BETWEEN 21W-24W. OTHER SCATTERED SHOWERS/TSTMS LIE N OF
25N BETWEEN 28W-36W IN ASSOCIATION WITH THE SURFACE TROUGH AND
UPPER LEVEL CUT-OFF LOW. THE LOW AND TROUGH ARE EXPECTED TO
CONSOLIDATE OVER THE NEXT FEW DAYS AND LIFT NE TOWARDS MADEIRA
ISLAND...THEN DROP BACK S TOWARDS THE CANARY ISLANDS BY WED.

$$
BERG


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