[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 082343
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI DEC 08 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
2330 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N10W 4N30W 4N50W.  SCATTERED
MODERATE CONVECTION IS FROM 2N-6N BETWEEN 35W-42W. CLUSTERS OF
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION SEEN FROM 1N-7N
BETWEEN 45W-60W...WHICH INCLUDES THE NE SOUTH AMERICA.

...DISCUSSION...
THE GULF OF MEXICO...
STRONG HIGH PRESSURE HAS TAKEN OVER THE GULF SFC PATTERN...FROM
A 1042 MB CENTER OVER ERN ARKANSAS. THIS IS PRODUCING WIDESPREAD
20 TO 25 KT NE FLOW ACROSS THE GULF...WITH WINDS TO GALE FORCE
IN THE SW PORTION S OF 25N AND W OF 94W. A SFC TROUGH IS IN THE
FAR W/SW GULF AS THE SYNOPTIC NE FLOW COLLIDES WITH THE MORE N
TO NW FLOW SLIDING DOWN THE SLOPES OF THE SIERRA MADRES. THE
TROUGH AT 2100 UTC WAS ANALYZED ALONG 26N97W 20N93W. NUMEROUS
LIGHT TO MODERATE RAIN SHOWERS ANTICIPATED WITHIN 100 NM OF THIS
FEATURE. EXTENSIVE MID TO UPPER MOISTURE IS ALSO SPREADING
ACROSS MUCH OF THE GULF THIS EVENING...CARRIED BY ZONAL UPPER
FLOW IN ADVANCE OF THE UPPER LOW SPINNING OVER NRN MEXICO. WINDS
AND SEAS WILL SUBSIDE STEADILY AS WE MOVE THROUGH THE
WEEKEND...ASIDE FROM THE FLORIDA STRAITS...WITH HIGH PRESSURE
SLOWLY WEAKENING AND MOVING E TO NE. A MODERATE E SWELL WILL
ALSO LINGER ACROSS TEXAS AND NE MEXICO BEACHES INTO EARLY NEXT
WEEK FROM THE FETCH S OF THE HIGH.

CARIBBEAN SEA...
THE ONLY SIGNIFICANT WEATHER IN THE CARIBBEAN THIS EVENING IS
ACROSS THE WRN PORTION...WHERE CLUSTERS OF SCATTERED MODERATE
CONVECTION DOT THE AREA FROM 9N-19N BETWEEN 79W-84W. THIS SEEMS
MOSTLY ASSOCIATED WITH SPEED CONVERGENCE DOWNSTREAM FROM THE
SWATH OF 15 TO 25 KT TRADES IN THE CENTRAL CARIBBEAN...THOUGH
WEAK SFC TROUGHING IN THE VICINITY IN ADDITION TO THE
APPROACHING FRONT MAY ALSO BE PROVIDING SOME TRIGGER. THE CLOUD
TOPS OVER THE CONVECTION ARE GETTING SHEARED TO THE E WITH UPPER
WLY FLOW OVER THE AREA. AS OF 2100 UTC...THE COLD FRONT EXTENDS
THROUGH THE NW CARIBBEAN FROM CENTRAL CUBA TO 16N85W IN THE GULF
OF HONDURAS. NE FLOW EXPECTED TO INCREASE IN THE NW CARIB BEHIND
THE FRONT TONIGHT AND SAT...AS STRONG HIGH PRESSURE BUILDS FROM
THE N. MODEL GUIDANCE SUGGESTS THE WRN CARIBBEAN WILL CONTINUE
TO SEE SCATTERED SHOWERS/TSTMS THROUGH THE WEEKEND...WITH SPEED
CONVERGENCE AND THE OLD FRONTAL BOUNDARY MEANDERING.

THE ATLANTIC OCEAN...
STRONG SFC HIGH PRESSURE IS BUILDING INTO THE SW NORTH ATLC OFF
THE FLORIDA COAST THIS EVENING...FROM A 1042 MB CENTER OVER ERN
ARKANSAS. THIS IS PRODUCING FRESH TO STRONG NE WINDS OVER MUCH
OF THE AREA N OF 24N AND W OF 65W...WHICH IS THE AREA BEHIND THE
COLD FRONT ALONG 32N63W TO 23N79W NEAR THE COAST OF CENTRAL
CUBA. WINDS TO GALE FORCE EXPECTED N OF 25N AND W OF 75W...OFF
OF NE FLORIDA...BUT THIS IS EXPECTED TO RELAX BY TOMORROW
AFTERNOON. LARGE NE WIND WAVES AND SWELL TO SPREAD THROUGH THE
SOUTH FLORIDA WATERS INTO SAT...SUBSIDING SLOWLY THROUGH EARLY
NEXT WEEK. SEE DETAILS IN COASTAL WATERS FORECASTS FROM LOCAL
WEATHER SERVICE OFFICES. UPPER FLOW OVER THE SW NORTH ATLC IS
MOSTLY SW AHEAD OF THE UPPER TROUGH OVER THE ERN SEABOARD.
DIFFLUENCE BETWEEN THIS FEATURE AND AN UPPER RIDGE EXTENDING NE
THROUGH THE LEEWARD ISLANDS INTO THE CENTRAL ATLC IS HELPING TO
SUPPORT THE SCATTERED MODERATE CONVECTION SEEN N OF 23N BETWEEN
60W-68W. THIS IS ALSO GETTING LIFT FROM A PREFRONTAL TROUGH
ALONG 30N64W 23N71W...WHICH SEEMS TO BE GETTING TAKEN OVER BY
THE MAIN COLD FRONT. AN UPPER TROUGH EXTENDS FROM THE E ATLC
NEAR 32N30W SW TO NEAR 13N52W. AN UPPER RIDGE EXTENDS UP THE
COAST OF W AFRICA...WHICH HAS ABUNDANT MID TO UPPER MOISTURE
SPREADING AROUND ITSELF. THE SFC PATTERN OVER THE E AND CENTRAL
ATLC REMAINS DOMINATED BY E FLOW ON THE SRN PERIPHERY OF A 1039
MB HIGH OVER THE AZORES.

$$
WILLIS


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