[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 062346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED DEC 06 2006

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2345 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N15W 5N30W 6N45W 4N54W. SMALL
CLUSTERS OF SCATTERED MODERATE CONVECTION NOTED WITHIN 90 NM OF
THE AXIS BETWEEN 29W AND 50W.

...DISCUSSION...
THE GULF OF MEXICO...
UPPER FLOW REMAINS MOSTLY ZONAL ACROSS THE GULF THIS
EVENING...ADVECTING QUITE A BIT OF MID TO UPPER MOISTURE ACROSS
THE AREA OUTSIDE OF THE BAY OF CAMPECHE...WHERE VERY DRY AIR
HAPPENS TO BE PRESENT. AVAILABLE BUOY/SHIP DATA AND SATELLITE
IMAGERY SUGGEST A SFC TROUGH HAS FORMED OVER THE GULF BETWEEN
PANAMA CITY FLORIDA AND THE YUCATAN CHANNEL. THIS IS REFLECTED
ON THE 2100 UTC MAP. THERE IS NO DEEP CONVECTION ASSOCIATED WITH
THIS TROUGH...THOUGH SCATTERED SHOWERS EXPECTED WITHIN 60 NM OF
THE AXIS. THE TROUGH IS PRODUCING A KINK IN THE ISOBARS AROUND
THE 1025 MB HIGH OVER SW GEORGIA. WINDS/SEAS HAVE SUBSIDED
SUBSTANTIALLY OVER THE GULF OVER THE LAST 24 HOURS...BUT
EXPECTED TO INCREASE THU/FRI BEHIND THE NEXT COLD FRONT. MOST OF
THE PRECIP/CONVECTION ASSOCIATED WITH THIS FRONT EXPECTED TO BE
LIMITED TO THE FAR WRN PORTION OFF S TEXAS AND MEXICO.

THE CARIBBEAN SEA...
A DYING STATIONARY FRONT EXTENDS FROM W CUBA TO NW HONDURAS
ALONG 24N80W 21N85W 16N88W.  THE BOUNDARY APPEARS RATHER
DISCONTINUOUS AND THUS WAS REMOVED FROM THE 2100 UTC MAP. A SFC
TROUGH EXTENDS N FROM NRN COLOMBIA THROUGH HAITI. SOME OF THIS
MAY BE MORE DUE TO THE NATURAL TRADE FLOW THROUGH THE CARIBBEAN
AND AROUND THE ADJACENT LAND MASSES. DEEP CONVECTION IS NON
EXISTENT ACROSS THE CARIBBEAN THIS EVENING...WITH EXTENSIVE DRY
MID TO UPPER AIR CONTINUING OVER THE AREA. UPPER RIDGING
DOMINATES THE WRN AND CENTRAL CARIBBEAN WHILE A WEAKENING UPPER
TROUGH IS OVER THE ERN CARIBBEAN. OVERALL E TO NE SFC
FLOW IS IN THE 15-20 KT RANGE ACROSS THE CARIBBEAN...WHICH IS
EXPECTED TO PERSIST INTO THU. THIS FLOW CONTINUES TO ADVECT
SCATTERED TO BROKEN LOWER CLOUDS WITH ISOLATED SHOWERS THROUGH
THE CARIBBEAN. A BIT STRONGER NE FLOW DEVELOPS IN THE NW PORTION
LATE FRI INTO SAT AS STRONG HIGH PRESSURE BUILDS N OF THE AREA.

THE ATLANTIC OCEAN...
A DYING STATIONARY FRONT IS OVER THE SW NORTH ATLC FROM THE
BAHAMAS TO 29N60W. A COLD FRONT EXISTS FROM THIS POINT TO
32N50W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM SE OF THE
COLD FRONT PORTION...N OF 28N BETWEEN 50W-55W. THE REMAINDER OF
THE FRONT IS MARKED BY BROKEN TO OVERCAST LOWER CLOUDS WITH
POSSIBLE LIGHT RAIN SHOWERS WITHIN 90 NM. THE SFC GRADIENT OVER
THE AREA OFF THE FLORIDA COAST HAS WEAKENED TODAY WITH HIGH
PRESSURE NEARING FROM GEORGIA...THOUGH NE WINDS AND WAVES
INCREASE BEHIND THE NEXT FRONT FRI AND SAT. SFC OBS AND
SATELLITE IMAGERY STILL SUGGEST A SFC TROUGH EXTENDS N THROUGH
THE TURKS AND CAICOS ISLANDS TO 25N71W. SCATTERED SHOWERS
POSSIBLE WITHIN 120NM OF THIS FEATURE. UPPER FLOW OVER THE WRN
ATLC IS ZONAL...AND IS ADVECTING HIGH MOISTURE/CLOUDS E FROM THE
FLORIDA COAST. A WEAKENING UPPER LOW/TROUGH NEAR THE LEEWARD
ISLANDS HAS SCATTERED SHOWERS/TSTMS FROM 7N-20N BETWEEN 55W-61W.
THIS AREA IS ALSO BEING SUPPORTED BY UPPER DIFFLUENT AIR BETWEEN
THE UPPER LOW OVER THE LEEWARDS AND THE UPPER RIDGE EXTENDING N
THROUGH THE TROPICAL ATLC...WHOSE AXIS IS ALONG 53W. A
PRONOUNCED UPPER LOW IS SEEN SPINNING OVER THE E ATLC WATERS
NEAR 20N32W...WHICH HAS ABUNDANT UPPER MOISTURE TO ITS S AND SE
THROUGH AFRICA. THE E AND CENTRAL ATLC SFC PATTERN IS DOMINATED
BY A 1033MB HIGH NEAR 33N23W.


$$
WILLIS




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