[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 052356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI 05 NOV 2004

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.

...TROPICAL WAVES...
TROPICAL WAVE LOCATED OVER GUATEMALA/SE MEXICO ALONG 91W S OF
18N MOVING W 5-10 KT.  WAVE IS TRACKED USING BROAD ROTATION IN
THE EPAC AND ITS INFLUENCE IN THE AREA IS LIMITED TO ISOLATED
SHOWERS.

...ITCZ...
ITCZ AXIS IS ALONG 8N12W 7N23W 5N33W 6N45W 4N52W.  ISOLATED
MODERATE WITHIN 60 NM OF LINE 5N23W 4.5N13W. SCATTERED MODERATE
IS FROM 4.5N-9.5N BETWEEN 23W-30W. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 4N-10N BETWEEN 30W-49W.

...DISCUSSION...
GULF OF MEXICO AND SW ATLANTIC...
COLD FRONT HAS SWEPT ACROSS FLORIDA AND THE GULF OF MEXICO...
EXTENDING FROM 31N72E TO THE STRAITS OF FLORIDA THEN INTO
YUCATAN.  SLOW PROGRESS TO THE SE IS EXPECTED WITH ONLY MARGINAL
UPPER ZONAL FLOW CONDITIONS SLOWLY CONTINUING THE SWD FRONTAL
PROGRESSION.   CLEAR SKIES DOMINATE AFTER A FEW HUNDRED MILES
BEHIND THE FRONT EXCEPT IN THE CENTRAL/SRN GULF AS LOW-LEVEL
INSTABILITY OVER WARM GULF SW ATLC WATERS IS LEADING TO NEARLY
SOLID DECKS OF STRATUS AND STRATOCUMULUS. ISOLATED SHOWERS ARE
POSSIBLE UP TO 100 NM BEHIND THE FRONT WITH SOME THICKER CLOUDS
AND SOME TSTMS POSSIBLE ALONG THE ISTHMUS OF TEHAUNTEPEC.
MODELS SUGGEST A LONG PERIOD OF GENERALLY NLY FLOW AT THE
SURFACE WITH OCCASIONAL REINFORCEMENTS OF DRIER CONTINENTAL AIR.

CARIBBEAN...
UPPER RIDGING IS IN THE W CARIBBEAN WHILE DEEP TROUGHING COVERS
THE E CARIBBEAN.  GENERALLY FAIR WEATHER SPANS THE CENTRAL
CARIBBEAN WHILE OVERCAST CONDITIONS AND WIDELY SCATTERED SHOWERS
ARE N OF 20N W OF 84W ASSOCIATED WITH AN INCOMING FRONTAL
SYSTEM.  UPPER RIDGE FROM COSTA RICA NWD TO THE YUCATAN CHANNEL
HAS ASSISTED WIDELY SCATTERED MODERATE CONVECTION WITHIN 90 NM
OF LINE 11N79W 18N84W.  FARTHER E... ISOLATED SHOWERS ARE S OF
PUERTO RICO E OF 70W BECOMING MORE NUMEROUS AND INTENSE IN THE
FAR SE CARIBBEAN AS A NEW SLUG OF MOISTURE ENTERS THE AREA.
THESE TSTMS ARE BEING FED BY A DEEP UPPER TROF THAT CARVES INTO
THE CARIBBEAN FROM HISPANIOLA TO NW VENEZUELA.  INCREASING
SHOWER CHANCES ARE LIKELY FOR THE LEEWARD ISLANDS INTO PUERTO
RICO THRU THE WEEKEND AS THIS MOISTURE ADVECTS NORTHWARD.
ADDITIONAL SHOWERS ARE LIKELY IN THE GREATER ANTILLES WITH AND
BEHIND AN EXPECTED COLD FRONT.

SUBTROPICAL ATLANTIC...
UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE W ATLC NEAR 25N61W
SLIDING EASTWARD AHEAD OF A DEEPENING UPPER TROUGH ALONG 82W.
COLD FRONT IS EMBEDDED WITHIN THE RIDGE EXTENDING ALONG 31N36W
26N49W THEN AS A DISSIPATING STATIONARY FRONT TO 26N64W.  BROKEN
BAND OF LOW/MID CLOUDINESS EXTENDS WITHIN 60 NM OF THE FRONT BUT
THERE IS NO DEEP CONVECTION. A SFC TROF IS LOCATED E OF THE
FRONT ALONG 32N31W 27N32W 22N40W 19N48W AND ISOLATED MODERATE
CONVECTION IS N OF 24N WITHIN 120 NM ALONG THE BOUNDARY.  WEAK
SURFACE RIDGING IS LOCATED ALONG 25W IN THE E ATLC WITH A LARGE
MID/UPPER LOW BETWEEN THE MADRAS ISLANDS AND PORTUGAL.

TROPICAL ATLANTIC...
MAIN FEATURE IS A SUBTROPICAL JET FROM JUST E OF THE LESSER
ANTILLES NEAR 14N60W AND EXTENDS E ACROSS THE ATLC ALONG 19N45W
19N15W WITH SPEEDS AS HIGH AS 55 KT W OF THE CAPE VERDE ISLANDS.
ANY RIDGING IS QUITE WEAK WITH GREATER MOISTURE IN THE MID/UPPER
LEVELS THAN AVERAGE.  LOW-LEVEL CONVERGENCE IS ALIGNED ALONG A
LINE FROM TRINIDAD TO 16N50W WITH WIDELY SCATTERED MODERATE
CONVECTION FROM 10N-16N BETWEEN 48W-61W. ALSO...A WEAK TROF IS
LOCATED ALONG 46W MOVING W 10-15 KT AND COULD REINFORCE
CONVECTION IN THE AREA E OF THE LESSER ANTILLES OVER THE
WEEKEND.  THE ABSENCE OF UPPER RIDGING IS ADDING TO THE
POTENTIAL OF UPPER DIVERGENCE OVER THE ITCZ SUPPORTING
WIDESPREAD CONVECTION ALONG THE AXIS E OF 50W.

$$
BLAKE

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