[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060534
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU DEC 06 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N11W 4N20W 4N32W 3N43W 2N51W.
SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N OF THE AXIS
BETWEEN 21W-25W AND 28W-31W. SIMILAR CONVECTION IS WITHIN 180 NM
EITHER SIDE OF THE AXIS BETWEEN 32W-41W.

DISCUSSION...

THE GULF OF MEXICO...
VERY WEAK SFC PRES PATTERN IN THE AREA IS RESULTING IN LIGHT AND
VARIABLE WINDS...EXCEPT 10-15 KT W TO NW WINDS IN THE NE GULF.
REMNANT SFC TROUGH IS NEARLY DISSIPATED ALONG 87W S OF 26N BUT
THERE IS STILL SOME ASSOCIATED PATCHES OF LOW-MID LEVEL
CLOUDINESS AND EMBEDDED SCATTERED SHOWERS/ISOLATED TSTMS E OF
THE WEAK BOUNDARY FROM 24N-26N E OF 86W. IN THE MID AND UPPER
LEVELS...A WELL DEFINED CUT OFF CONTINUES TO SIT AND SPIN OVER
CENTRAL MEXICO. EXTENSIVE SWLY FLOW ALOFT IS ADVECTING A PLUME
OF HIGH LEVEL CLOUDINESS ACROSS MUCH OF THE W GULF. THESE MAINLY
QUIET CONDITIONS WILL LIKELY CONTINUE THROUGHOUT THE DAY TODAY
BEFORE A SLIGHT INCREASE IN LOW-LEVEL MOISTURE ACROSS THE WRN
HALF AS LOW-LEVEL RETURN FLOW SETS UP.

THE CARIBBEAN SEA...
QUIET CONDITIONS DOMINATE MUCH OF THE CARIB BASIN THIS EVENING
WITH NIGHT CHANNEL VIS IMAGERY ONLY REVEALING TYPICAL NARROW
SCATTERED STREAMS OF LOW-LEVEL CLOUDINESS. SAN JUAN DOPPLER
RADAR DEPICTS SOME EMBEDDED SHOWER ACTIVITY MOSTLY S OF THE
ISLAND...BUT MUCH LESS SO THAN THE PAST FEW DAYS. LIKE THE GULF
OF MEXICO...WEAK SFC PRES PATTERN INDUCED BY THE FRONTAL
BOUNDARY N OF THE AREA IS ALLOWING ELY TRADES TO BE LIGHT ACROSS
THE ENTIRE AREA...EVEN VARIABLE IN THE NW CARIB AS NOTED IN A
RECENT QSCAT PASS. ALOFT...SW TO WLY FLOW IS THE THEME ON THE NW
SIDE OF A VERY BROAD RIDGE CENTERED ABOVE THE TROPICAL ATLC. A
SWATH OF MID-HIGH LEVEL CLOUDINESS IS SEEN ON WV IMAGES IN THE
SW CARIB S OF 15N W OF 76W AND IN THE SE CARIB S OF 14N W OF 68W
BUT NOT MUCH SENSIBLE WEATHER. THE RELAXED TRADE WIND FLOW IS
NOT EXPECTED TO LAST MUCH LONGER AS STRONG RIDGING BUILDS NE OF
THE AREA. WINDS ARE EXPECTED TO INCREASE FROM E-W LATER TODAY.

THE ATLANTIC OCEAN...
COLD FRONT HAS BECOME VERY DIFFUSE IN THE CENTRAL AND W ATLC
ANALYZED FROM 32N54W TO 25N70W. SAT IMAGERY AND LAST COUPLE SCAT
PASSES SHOW LIMITED LOW-LEVEL CONVERGENCE ALONG THE BOUNDARY SO
MAY DECIDE TO DISSIPATE OR EVEN DROP THE BOUNDARY ON THE 06Z
MAP. A CLUSTER OF TSTM ACTIVITY...WHICH APPEARS TO BE ASSOCIATED
WITH MID-LEVEL VORTICITY...HAS BEEN TRAVELING NE WITH THE MID
AND UPPER FLOW CURRENTLY FROM 27N-29N BETWEEN 67W-69W. THE
REMAINDER OF THE AREA W OF 50W IS FAIRLY QUIET UNDER MODERATELY
STABLE AIR AND FAIRLY UNIFORM ZONAL UPPER FLOW.

THE CENTRAL AND E ATLC IS DOMINATED BY STRONG SFC RIDGING
ANCHORED BY A 1036 MB HIGH E OF THE AZORES NEAR 38N18W. WEAK
LOW-LEVEL TROUGHING APPEARS TO BE DEVELOPING ALONG 40W OR SO
FROM 24N SWD AS DEPICTED BY LOW-LEVEL CYCLONIC TURNING SEEN IN
THE LATEST SAT IMAGES. ASSOCIATED SCATTERED SHOWERS EXIST FROM
17N-23N BETWEEN 38W-41W. STRONG ELY TRADES COVER MUCH OF THE
AREA E OF THE TROUGH. THE MID AND UPPER PATTERN IS QUITE
AMPLIFIED CONSISTING OF A LARGE ANTICYCLONE OVER THE AZORES AND
A BROAD ELONGATED TROUGH TRAPPED S OF THE HIGH. THE BROAD TROUGH
CONSISTS OF A PAIR OF UPPER LOWS CENTERED NEAR 24N33W AND
ANOTHER JUST E OF THE CAPE VERDE ISLANDS NEAR 27N20W. STRONG
UPPER WINDS ON THE S SIDE OF THE TROUGH IS GENERATING AND
TRANSPORTING SCATTERED SHOWERS AND TSTMS N OF THE ITCZ ROUGHLY
FROM 4N-11N BETWEEN 35W-46W.

$$
CANGIALOSI




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