[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040559
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST THU JAN 04 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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
0545 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 1N AT THE PRIME MERIDIAN TO 3N15W
4N30W 2N40W CROSSING THE EQUATOR AT 46W TO NE BRAZIL NEAR 1S48W.
ISOLATED MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE
AXIS BETWEEN 15W-21W. SCATTERED MODERATE IS WITHIN 90NM N OF THE
AXIS BETWEEN 23W-31W.

...DISCUSSION...
GULF OF MEXICO...
SCATTERED TO NUMEROUS MODERATE CONVECTION IS IN THE NW GULF
TONIGHT...N OF 24N AND W OF 87W. THIS IS BEING SUPPORTED BY
UPPER DIFFLUENT FLOW BETWEEN THE UPPER LOW MOVING THROUGH NRN
MEXICO AND THE UPPER RIDGE EXTENDING NE THROUGH MUCH OF THE GULF
FROM ITS ORIGIN S OF EL SALVADOR. FURTHER...THE SFC SUPPORT IS
DRIVEN BY A NEW 1013 MB LOW JUST OFF THE COAST OF S TEXAS...THAT
HAS A WARM FRONT EXTENDING ENE THROUGH THE MIDDLE GULF AND INTO
NORTH CENTRAL FLORIDA. THE SURFACE LOW WILL MOVE NE OF THE AREA
AND DRAG A COLD FRONT THROUGH THE NW GULF THROUGH THU NIGHT.
15-20 KT SE TO S FLOW EXPECTED AHEAD OF THE FRONT/LOW INTO THU
MORNING/AFTERNOON WHILE SIMILAR W TO NW WINDS DEVELOP BEHIND THE
FRONT. WINDS BEHIND THE FRONT DIMINISH THROUGH THU NIGHT AS WEAK
HIGH PRESSURE BUILDS OFF THE TX COAST.

CARIBBEAN SEA...
AN UPPER HIGH JUST S OF EL SALVADOR EXTENDS A RIDGE OVER THE
YUCATAN PENINSULA AND NW CARIBBEAN. AN UPPER TROUGH EXTENDS FROM
HISPANIOLA/PUERTO RICO TO PANAMA. VERY DRY AIR...RESULTING IN
STRONG SUBSIDENCE DOMINATES THE BASIN. ONLY PATCHES OF LOW LEVEL
MOISTURE ARE BEING CARRIED BY THE TRADE WINDS ACROSS THE REGION.
THIS IS PRODUCING ISOLATED SHOWERS OVER MANY OF THE CARIBBEAN
ISLANDS AND THEIR ADJACENT WATERS TONIGHT. SAN JUAN RADAR
IMAGERY SHOWS THE SHOWERS ARE CURRENTLY FOCUSED IN THE COASTAL
WATERS JUST NORTH OF PUERTO RICO. A GALE WARNING REMAINS IN
EFFECT NEAR THE COAST OF COLOMBIA. 20-30 KT TRADEWINDS ARE OVER
THE REMAINDER OF THE CARIBBEAN SEA. HIGH PRES OVER ATLC WILL
CONTINUE TO PRODUCE FRESH TO STRONG E TRADE WINDS THROUGH SUN
WITH GALE CONDITIONS JUST OFF OF THE COLOMBIAN COAST THROUGH
THU.

ATLANTIC OCEAN...
DEEP LAYERED TROUGH OVER THE NW ATLC IS SUPPORTING A COLD FRONT
THAT ENTERS THE REGION NEAR 31N54W...THEN CONTINUES MAINLY WWD
TO 29N61W WHERE IT BECOMES A STATIONARY FRONT THROUGH
29N74W...AND THEN CONTINUES AS A WARM FRONT THROUGH NORTH
CENTRAL FLORIDA. SCATTERED SHOWERS ARE ASSOCIATED WITH THE
FRONTAL BOUNDARY. THE UPPER RIDGE EXTENDING THROUGH THE GULF AND
SW NORTH ATLC WATERS OFF OF FLORIDA IS ADVECTING MOISTURE INTO
THE REGION DOWNSTREAM FROM THE CONVECTION OVER THE GULF. A
SHORTWAVE TROUGH IS N OF 25N ALONG 72W...WHILE AN UPPER RIDGE
COVERS MUCH OF THE REMAINDER OF THE W-CENTRAL ATLC...EXTENDING
NE FROM THE LEEWARD ISLANDS THROUGH 32N47W. AN UPPER LOW IS NEAR
22N40W. A TROUGH EXTENDS FROM THIS LOW TO NEAR 12N50W. A SURFACE
TROUGH...REFLECTION OF THE UPPER LOW IS ANALYZED FROM 24N44W TO
18N45W. BROAD RIDGE COVERS THE REMAINDER OF THE ATLC. THIS RIDGE
IS DRAWING TROPICAL MOISTURE N ON THE E SIDE OF THE UPPER TROUGH
GENERATING SCATTERED SHOWERS N OF 10N AND E OF 40W. A 1036 MB
SURFACE HIGH LOCATED JUST NORTH OF THE MADEIRA ISLANDS EXTENDS A
RIDGE OVER THE E ATLC. THE TAIL END OF A DYING STATIONARY FRONT
ENTERS THE AREA NEAR 31N34W THEN CONTINUES SW TO NEAR 24N45W.

$$
WILLIS




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