[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 030546
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST MON DEC 03 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 IS CENTERED ALONG 9N13W 5N24W 5N40W 2N51W. AXIS IS ACTIVE
TONIGHT WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION
COVERING A LARGE AREA FROM 4N-8N BETWEEN 16W-31W. SIMILAR
CONVECTION IS FROM 5N-9N BETWEEN 38W-47W ENHANCED BY A SFC
TROUGH ALONG 42W/43W.

DISCUSSION...

THE GULF OF MEXICO...
DIGGING MID TO UPPER SHORTWAVE OVER TEXAS AND NRN MEXICO IS
SUPPORTING A COLD FRONT WHICH HAS JUST ENTERED THE FAR NW CORNER
OF THE REGION FROM SW LOUISIANA TO S TEXAS. LOW-LEVEL
CONVERGENCE NEAR THE BOUNDARY IS GENERATING A NARROW LINE OF
SCATTERED SHOWERS AND TSTMS WITHIN 30 NM AS NOTED IN DOPPLER
RADAR. NLY WINDS SIGNIFICANTLY INCREASE BEHIND THE BOUNDARY
ADVECTING IN A COOLER AND MUCH DRIER AIRMASS. THE REMAINDER OF
THE GULF IS VERY TRANQUIL AT THE MOMENT WITH LIGHT AND VARIABLE
WINDS AND ONLY A FEW PATCHY CLOUDS SUPPRESSED BY WIDESPREAD
STABLE AIR ALOFT. THE FRONT IS EXPECTED TO CONTINUE ITS SE
PROGRESS ALLOWING THE AIRMASS CHANGE TO SPREAD ACROSS MOST OF
THE AREA WITHIN THE NEXT 24-36 HOURS.

THE CARIBBEAN SEA...
STRONG LOW-LEVEL N TO NE WINDS TO THE W OF A LOW PRES SYSTEM IN
THE CENTRAL ATLC IS DRIVING STREAMS OF LOW-LEVEL CLOUDS AND
SHOWERS ACROSS THE LEEWARD ISLANDS AND INTO THE CENTRAL CARIB
ROUGHLY FROM 14N-17N E OF 76W. WIND SPEED CONVERGENCE APPEARS TO
BE CAUSING A SLIGHT ENHANCEMENT IN THE CLOUD COVER MIDWAY
BETWEEN SOUTH AMERICA AND HISPANIOLA. MUCH OF THE WRN CARIB IS
EXPERIENCING FAIR WEATHER UNDER THE INFLUENCE OF MID TO UPPER
RIDGING AND ABUNDANT SUBSIDENCE. NELY TRADE WIND FLOW IS
STRONGEST...20-25 KT...IN THE CENTRAL CARIB TONIGHT. THIS FLOW
SHOULD SLACKEN BASIN WIDE AND IS EXPECTED TO BE BELOW 20 KT
AROUND THIS TIME TOMORROW.

THE ATLANTIC OCEAN...
A COLD FRONT IS MOVING ACROSS THE CENTRAL AND SW ATLC ANALYZED
FROM 32N47W TO 22N70W CONTINUING NW ACROSS THE BAHAMAS AS A
NON-THERMAL BOUNDARY. BROKEN PATCHES OF CLOUDS AND POSSIBLE
ISOLATED SHOWERS ARE WITHIN 60 NM OF THE FRONT. DEEP LAYER
RIDGING IS IN PLACE BEHIND THE BOUNDARY ALLOWING FAIR WEATHER TO
DOMINATE. THE SFC CENTER IS ANALYZED 1027 MB JUST NW OF BERMUDA.
IN THE CENTRAL ATLC...A 1010 MB LOW HAS BEEN NEARLY STATIONARY
IN THE VICINITY OF 24N53W. THIS LOW SITS ALONG AN SFC TROUGH
WHICH HAS BECOME STRETCHED N OF THE LOW DUE TO THE APPROACHING
COLD FRONT MENTIONED ABOVE. CONVECTION HAS BEEN ON THE DECREASE
OVER THE PAST FEW HOURS...SCATTERED MODERATE IN NATURE...FROM
22N-24N BETWEEN 49W-52W.  A LARGER AREA OF CLOUDINESS AND
EMBEDDED SCATTERED SHOWERS IS LOCATED TO THE E OF THE SFC LOW IN
AN UPPER DIFFLUENT ZONE BETWEEN 38W-46W N OF 18N. ANOTHER
QUASI-STATIONARY SFC TROUGH IS ALONG 55W/56W FROM 7N-16N. THIS
FEATURE HAS BECOME BETTER DEFINED TONIGHT AND A WEAK AREA OF LOW
PRES MIGHT BE FORMING ALONG THE AXIS IN THE VICINITY OF 13N.
SCATTERED SHOWERS AND TSTMS ARE MAINLY TO THE E OF THE TROUGH
AXIS... SHEARED BY UPPER SWLY FLOW...FROM 14N-16N BETWEEN
51W-53W.

THE ERN ATLC IS DOMINATED BY SFC RIDGING EXTENDING SWD FROM A
1029 MB HIGH MIDWAY BETWEEN THE AZORES AND THE IBERIAN
PENINSULA. NE TO ELY TRADES ARE STRONGEST FROM 16N-25N E OF THE
CAPE VERDE ISLANDS AS SUGGESTED BY A PARTIAL ASCAT PASS. THE MID
AND UPPER FLOW IS MAINLY W TO NW ACROSS THIS REGION BETWEEN
RIDGING STRETCHING NWD FROM THE EQUATOR...AND A LARGE UPPER
TROUGH EXTENDING SW FROM EUROPE THRU THE CANARY ISLANDS. STRONG
FLOW BETWEEN THESE SYSTEMS IS ADVECTING HIGH LEVEL CLOUDINESS
MAINLY S OF 23N. A WEAK UPPER LOW CENTERED NEAR 29N25W IS
PRODUCING SIMILAR CLOUDINESS WITHIN 90 NM OF THE CENTER.

$$
CANGIALOSI




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