[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181100
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU JAN 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N11W 5N20W 3N30W 2N52W. ISOLATED
CLUSTERS OF MODERATE CONVECTION ARE WITHIN 120NM OF THE AXIS
BETWEEN 22W-33W AND BETWEEN 41W-52W.

...DISCUSSION...
GULF OF MEXICO...
THIS MORNINGS WV IMAGERY CONTINUES TO SHOW SUBTROPICAL JET
SPREADING SIGNIFICANT AMOUNT OF MID TO UPPER MOISTURE FROM THE
NE PAC...THROUGH NRN MEXICO...TEXAS...AND CLIPPING THE NRN GULF
WATERS. MUCH DRIER AIR IS PRESENT SE OF A LINE FROM TAMPICO
MEXICO TO TAMPA FLORIDA. UPPER PATTERN REMAINS DOMINATED BY
RIDGING. SHORTWAVE IR IMAGERY DEPICTS BROKEN TO OVERCAST LOW
CLOUDS BEHIND THE LINGERING SFC FRONTAL BOUNDARY...WHICH AS OF
0900 UTC EXTENDS W AS A COLD FRONT FROM S FLORIDA TO
26N85W...THANKS TO THE RECENTLY FORMED SFC LOW NEAR COCOA BEACH.
FRONT THEN EXTENDS W AS A STATIONARY FRONT TO 26N95W...THEN SSE
THROUGH THE CENTRAL BAY OF CAMPECHE. LIGHT RAIN CAN BE EXPECTED
BEHIND THE FRONT WITH THE ISENTROPIC LIFT OCCURRING. WINDS AND
SEAS WILL CONTINUE TO RELAX ACROSS THE GULF TODAY AS THE HIGH
OVER NE MEXICO WEAKENS...IN ADDITION TO THE NEW LOW OFF FLORIDA
AND COASTAL FRONT OFF THE SE COAST PRODUCING A WEAKNESS IN THE
ONCE WELL ESTABLISHED SFC RIDGE OVER THE AREA. HOWEVER...NE
WINDS AND WIND WAVES TO INCREASE AGAIN IN NW PORTION TONIGHT
THROUGH SAT AS LINGERING TROUGH INTERACTS WITH REINFORCING
CONTINENTAL HIGH PRESSURE.

CARIBBEAN SEA...
EXTENSIVE DRY AIR IN THE MID TO UPPER LEVELS CONTINUES TO
SUPPRESS CONVECTION OVER THE ENTIRE CARIBBEAN. MODERATE TO
STRONG TRADE WINDS ALSO CONTINUE OVER THE CARIBBEAN BASIN WITH
THE MAXIMA REMAINING NEAR THE COLOMBIAN COAST AROUND 30 KT. THE
TRADES ARE ADVECTING TYPICAL PATCHES OF LOW LEVEL MOISTURE WITH
EMBEDDED SHOWERS ACROSS THE AREA. SIMILAR CONDITIONS EXPECTED
ACROSS THE CARIBBEAN THROUGH THE WEEKEND.

ATLANTIC OCEAN...
UPPER RIDGE IS BUILDING INTO THE SW N ATLC BEHIND A
WEAKENING UPPER TROUGH. THIS IS ADVECTING HIGH CLOUDS/MOISTURE
EWD FROM THE SE U.S. COAST INTO THE ATLC WATERS N OF 26N W OF
55W. SIGNIFICANT DRY UPPER AIR IS OVER THE SW N ATLC S OF 26N
THROUGH THE CARIBBEAN. STRONG SFC HIGH PRESSURE REMAINS OVER THE
W ATLC BEHIND THE COLD FRONT THAT ENTERS THE AREA AT 32N57W AND
CONTINUES SW TO 27N72W WHERE IT CONTINUES WNW AS A WARM FRONT TO
THE NEWLY FORMED WEAK SFC LOW NEAR COCOA BEACH. BROKEN LOW
CLOUDS/LIGHT RAIN SEEN OVER THE AREA BEHIND THE FRONT...IN
ADDITION TO MODERATE TO STRONG NE TO E WINDS/WAVES. WINDS WILL
BACK OFF DURING THE DAY AS THE LOW LIFTS NE AND PRODUCES A
WEAKNESS IN THE RIDGE. HOWEVER...ASSOCIATED MODERATE NLY SWELL
WILL STILL BE FELT FROM THE OLD FRONT AS IT SPREADS E THROUGH
THE AREA...PEAKING IN THE SE BAHAMAS TONIGHT AND AT EXPOSED
PUERTO RICO BEACHES DURING SAT...THEN SUBSIDING FROM W TO E.
CENTRAL ATLC IS DOMINATED BY THE 1016 MB SFC LOW NEAR 23N52W.
THIS HAS A MERIDIONAL SFC TROUGH WITH IT FROM 14N-29N...AND IS A
REFLECTION OF THE UPPER TROUGH EXTENDING THROUGH THE AREA.
ASSOCIATED SCATTERED MODERATE CONVECTION IS FROM 20N-26N BETWEEN
45W-52W. ABUNDANT MOISTURE WITH POSSIBLE SCATTERED SHOWERS ARE
ELSEWHERE FROM 11N-21N BETWEEN 37W-47W. ANOTHER UPPER LOW IS
OVER THE E ATLC NEAR 22N27W...THAT ALSO HAS SIGNIFICANT MOISTURE
WITH EMBEDDED SHOWERS MAINLY TO ITS E FROM 12N-27N BETWEEN
AFRICA AND 27W. THERE MAY BE A WEAK REFLECTION OF THIS AT THE
SFC...THOUGH THE E ATLC SFC PATTERN IS GENERALLY DOMINATED BY
MODERATE E TO NE WINDS S OF THE RIDGING FROM SW EUROPE.

$$
WILLIS


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