[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041743
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT 04 DEC 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 6N17W 2N30W 4N41W 3N50W.
WIDELY SCATTERED MODERATE CONVECTION WITHIN 120 NM OF THE AXIS
BETWEEN 10W-17W. ISOLATED MODERATE WITHIN 200 NM S OF THE AXIS
BETWEEN 20W-25W AND WITHIN 90 NM OF THE AXIS BETWEEN 28W-33W.

...DISCUSSION...

NORTHEAST MEXICO AND THE GULF OF MEXICO...
WIDESPREAD CLOUDINESS AND SHOWERS EXTEND UP TO 300 NM OFF THE
U.S. GULF COAST AS THE RESULT OF A 1014 MB LOW LOCATED ABOUT 80
NM ENE OF BROWNSVILLE TEXAS AND A WARM FRONT WHICH EXTENDS TO
THE E TO 27N90W 25N87W. THE LOW IS FUNNELING MOIST NORTHERLY
FLOW OVER S TEXAS AND NE MEXICO AND LOW CLOUDS ARE BANKING UP
AGAINST THE SIERRA MADRES...WITH VISIBILITIES DROPPING TO AS
LOW AS 5 MILES IN AREAS. OVERRUNNING IS PRODUCING MOSTLY LOW/MID
LEVEL CLOUDS BUT UPPER LEVEL JET DYNAMICS AND LOCALIZED
CONVERGENCE ALONG THE WARM FRONT ARE ALSO INITIATING SCATTERED
MODERATE CONVECTION OVER THE NE GULF FROM 26N-29N BETWEEN
85W-89W. WSR-88D ALSO INDICATES THAT SOME OF THESE SHOWERS/TSTMS
ARE RACING EWD ACROSS NRN PORTIONS OF FLORIDA INTO THE W ATLC.
THE UPPER LEVEL FLOW HAS AMPLIFIED A BIT SINCE YESTERDAY WITH A
TROF DEVELOPING OVER THE SOUTHEAST UNITED STATES AND NOW
CENTERED ALONG 86W. STRONGER RIDGING IS DEVELOPING BEHIND THE
TROF WITH MOISTURE INCREASING OVER NORTHERN MEXICO AND THE
SOUTHERN ROCKIES.

CARIBBEAN...
VERY QUIET CONDITIONS ACROSS THE CARIBBEAN BASIN TODAY ARE THE
RESULT OF VERY DRY AIR ACROSS THE ENTIRE REGION...CENTERED
AROUND AN UPPER LOW ABOUT 150 NM NW OF THE COLOMBIAN COAST WHICH
SPLIT OFF FROM A LARGER TROF OVER THE ATLC OCEAN. VERY STRONG
SUBSIDENCE NEAR THE LOW IS KEEPING THE DRIEST AIR OVER THE SW
CARIBBEAN BUT IS ALSO DRAWING A MINISCULE AMOUNT OF MOISTURE
FROM SOUTH AMERICA NWD OVER THE E CARIBBEAN. WIDELY SCATTERED
SHOWERS HAVE DEVELOPED WITHIN THIS AIR MASS FROM 12N-16N BETWEEN
64W-70W EXTENDING NE OF ARUBA. A FEW SHOWERS HAVE ALSO DEVELOPED
E OF ST. LUCIA TO THE N OF THE BARBADOS.

ATLANTIC...
A BROAD UPPER LEVEL TROF OVER THE SOUTHEAST UNITED STATES HAS
FORCED A COLD FRONT EWD OVER THE W ATLC WATERS ALONG 32N60W
26N73W BUT THE BOUNDARY HAS BECOME STATIONARY FARTHER W OVER THE
FLORIDA STRAITS AS THE UPPER FLOW HAS FLATTENED. A FEW SHOWERS
ARE RUNNING EWD ACROSS N FLORIDA INTO THE FAR W ATLC BUT
OTHERWISE THERE IS VERY LITTLE ACTIVE WEATHER ALONG THE FRONT.
FARTHER E...THE REMNANTS OF TROPICAL STORM OTTO CONTINUE TO SPIN
NEAR 26N51W BUT THE CLOUD AREA HAS LOST ALL DEEP CONVECTION. AN
UPPER LEVEL TROF DIPS DOWN INTO THE TROPICS TO THE E OF THE
LESSER ANTILLES AND THIS FEATURE IS BRINGING MOSTLY DRY AIR WITH
IT ACROSS THE ENTIRE AREA. THE TROF IS BEGINNING TO MERGE WITH A
SMALL UPPER LOW LOCATED NEAR 30N37W AND THE UPPER DIVERGENCE TO
THE E OF THE COMBINED TROF IS PRODUCING WIDESPREAD MID/UPPER
LEVEL CLOUDINESS OVER THE E ATLC. A WEAK SFC BOUNDARY APPEARS TO
BE LOCATED BENEATH THE UPPER LOW...WHICH HAS INITIATED SCATTERED
SHOWERS IN AN AREA FROM 23N-32N BETWEEN 31W-38W. STRONG RIDGING
IS CENTERED OVER THE E ATLC ALONG 28W WITH A HIGH NEAR 8N27W
WHILE A LARGE COMPLEX TROF IS SKIRTING ACROSS THE CANARY ISLANDS
AND N MOROCCO/ALGERIA.

$$
BERG



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