[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251751
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAR 25 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N9W 4N20W 2N35W 2N45W AND INTO NE
BRAZIL NEAR 1S51W. FAIRLY LARGE CLUSTER OF NUMEROUS
MODERATE/ISOLATED STRONG CONVECTION IS S OF THE AXIS FROM 4S-4N
BETWEEN 10W-15W. THIS SEEMS TO BE MORE ASSOCIATED WITH A
SECONDARY REGION OF TROUGHING/SPEED CONVERGENCE S OF THE MAIN
ITCZ...AND MAY NEED TO BE ADDED TO THE 1800 UTC MAP. ISOLATED
SHOWERS/TSTMS EXIST ELSEWHERE WITHIN 120 NM EITHER SIDE OF THE
AXIS...EXCEPT FOR SCATTERED ACTIVITY NEAR THE BRAZIL COAST FROM
3S-5N BETWEEN 44W-53W.

...DISCUSSION...

GULF OF MEXICO...
SFC HIGH PRESSURE OVER THE SE U.S. CONTINUES TO EXTEND SW OVER
THE GULF AND IS THE DRIVING FORCE IN TODAYS MARINE WEATHER. THE
HIGH IS PRODUCING ABUNDANT MODERATE TO FRESH (11-21 KT ON THE
BEAUFORT SCALE) E TO SE WINDS ACROSS THE BASIN. THESE WINDS HAVE
LEVELED OFF THE SEAS IN THE 3-6 FT RANGE. WAVE SPECTRA ACROSS
THE GULF ARE GENERALLY DOMINATED BY STEEP WIND WAVES WITH PEAK
PERIODS MOSTLY IN THE IN THE 5-7 SEC BAND. LARGER AND STEEPER
WAVES SHOULD BE ANTICIPATED IN THE STRAITS OF FLORIDA WITH THE
ELY FLOW AGAINST THE OPPOSING GULF STREAM. VERY LITTLE SHOWER OR
TSTM ACTIVITY NOTED ACROSS THE GULF THIS AFTERNOON...THOUGH MORE
ACTIVITY IS NOTED OVER NRN MEXICO AND TX. THIS IS ASSOCIATED
PRIMARILY WITH A FAIRLY SHARP MID TO UPPER LEVEL TROUGH
EXTENDING SSW THROUGH ARIZONA/NEW MEXICO TO THE NE PACIFIC WITH
AN EMBEDDED LOW CENTER NOTED IN THE CENTRAL GULF OF CALIFORNIA.
UPPER DIFFLUENCE BETWEEN THE TROUGH AND THE DOMINATING UPPER
RIDGE OVER THE GULF IS SUPPORTING THE SHOWER/TSTM ACTIVITY OVER
MEX/TX. ASSOCIATED UPPER MOISTURE IS SPREADING INTO THE WRN GULF
W OF 90W WITH WNW FLOW. SFC RIDGING WILL KEEP SIMILAR CONDITIONS
ACROSS THE GULF INTO EARLY WEEK. THE MID TO UPPER TROUGH WILL
MOVE THROUGH TX DURING MON AND TUE. MOST OF THE ASSOCIATED
SHOWER/TSTM ACTIVITY IS EXPECTED TO STAY INLAND THOUGH SOME MAY
SPILL INTO THE FAR NW GULF.

CARIBBEAN...
MOST ACTIVE WEATHER IN THE CARIBBEAN CONTINUES TO BE BETWEEN
JAMAICA AND THE TURKS AND CAICOS ISLANDS. BROKEN TO OVERCAST
MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS ARE FROM 16N-24N
BETWEEN 68W-78W. LIGHTNING DATA HAVE CONTINUED TO DEPICT
ISOLATED TO SCATTERED TSTMS IN THIS VICINITY AS WELL. THE
DRIVING WEATHER SUPPORT FOR THIS ACTIVITY IS A MID TO UPPER LOW
BETWEEN JAMAICA AND CUBA NEAR 19N78W. THIS HAS A SFC REFLECTION
AS A TROUGH EXTENDING THROUGH THE WINDWARD PASSAGE. GFS SUGGESTS
THIS AREA WILL DRIFT SLOWLY E EARLY THIS WEEK...SO MARINE
INTERESTS NEAR HISPANIOLA SHOULD ANTICIPATE SHOWER ACTIVITY WITH
EMBEDDED TSTMS TO PERSIST OVER THE NEXT DAY OR SO. MUCH OF THE
REMAINDER OF THE CARIB IS EXPERIENCING 10-20 KT TRADES EXCEPT A
BIT STRONGER NE WINDS S OF CUBA...MAINLY N OF 18N AND W OF 78W
WHERE A TIGHTER GRADIENT EXISTS. SIMILAR TRADE FLOW EXPECTED
THROUGH EARLY WEEK.

ATLANTIC...
THE INTERACTION BETWEEN HIGH PRESSURE OVER THE SE U.S. AND A
PAIR OF SFC TROUGHS IN THE WRN ATLC CONTINUE TO PRODUCE 15-25 KT
NE WINDS NEAR THE BAHAMAS AND ATLC WATERS FROM 20N-29N W OF 65W.
A REINFORCING COLD FRONT...CURRENTLY JUST S OF CAPE HATTERAS
ASSOCIATED WITH A DEEPENING 1005 MB LOW NEAR 38N61W...WILL
EXPAND THIS REGION OF HIGH NE WINDS IN THE WRN ATLC EARLY THIS
WEEK. MODERATE TO STRONG...STEEP WIND WAVES/SWELL SHOULD ALSO BE
ANTICIPATED IN THIS REGION. SEE OFFSHORE WATERS FORECAST UNDER
AWIPS HEADER MIAOFFNT3 FOR MORE DETAILS. THE SFC TROUGHING IN
THE WRN/CENTRAL ATLC AND CARIB IS PRODUCING SCATTERED SHOWER
ACTIVITY OVER MUCH OF THE AREA FROM 19N-28N BETWEEN 47W-80W.
THIS IS BEING ENHANCED BY A LARGE FETCH OF UPPER WSW FLOW
THROUGH THE SAME AREA. THE REMAINDER OF THE E AND CENTRAL ATLC
SFC PATTERN IS DOMINATED BY A 1029 MB HIGH SW OF THE AZORES NEAR
38N31W. THIS IS PRODUCING WIDESPREAD 15-20 KT TRADES AND FAIR
WEATHER E OF 55W. UPPER FLOW IS HIGHLY ZONAL OVER THIS PORTION
OF THE ATLC AS WELL.

$$
WILLIS


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