[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 062356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU APR 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...WEATHER OBSERVATIONS...
RADAR...AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 3N25W 2N40W EQ50W.  WIDELY
SCATTERED MODERATE CONVECTION IS FROM 1N-6N BETWEEN 14W-17W...
AND FROM 2N-4N BETWEEN 35W-40W.  SCATTERED SHOWERS AND TSTMS ARE
ELSEWHERE WITHIN 90 EITHER SIDE OF THE ITCZ AXIS.

...DISCUSSION...

GULF OF MEXICO...
1018 MB HIGH IS N OF THE BAHAMAS PRODUCING RETURN SLY FLOW OVER
THE ENTIRE GULF OF MEXICO.  THE SURFACE PRESSURE GRADIENT IS
TIGHTER OVER THE W GULF W OF 87W THUS WIND VELOCITIES ARE 15-20
KT.  5-10 KT WINDS ARE NOTED E OF 87W.  WARM FAIR WEATHER
PREVAILS OVER THE ENTIRE GULF.  A COLD FRONT IS INLAND OVER
CENTRAL TEXAS AND IS FORECAST TO ENTER THE W GULF FRIDAY NIGHT.
THE FRONT WILL INITIALLY LACK APPRECIABLE MOISTURE. SHOWERS/
TSTMS ARE EXPECTED TO BE LIMITED OVER THE W GULF.  IN THE UPPER
LEVELS... HIGH AMPLITUDE MIDDLE TO UPPER LEVEL RIDGE DOMINATES
THE PATTERN ALOFT OVER THE GULF.  RIDGE AXIS IS ALONG 88W.  AN
UPSTREAM TROUGH IS OBSERVED ADVANCING EWD OVER THE WESTERN TO
CENTRAL UNITED STATES BUT NEARLY ALL OF THE ASSOCIATED
DYNAMICS/LIFT ARE CONFINED N OF THE AREA.  THE ATTENDANT COLD
FRONT...MENTIONED ABOVE...IS PUSHING SWD TOWARDS THE GULF.

CARIBBEAN SEA...
THE SURFACE GRADIENT BETWEEN THE W ATLANTIC HIGH AND THE LOW
OVER INLAND COLOMBIA IS NOT VERY TIGHT THUS TRADEWINDS OVER THE
CARIBBEAN ARE RUNNING BELOW NORMAL.  NO SIGNIFICANT CONVECTION
IS NOTED.  THE REMNANTS OF AN OLD FRONTAL BOUNDARY...HOWEVER...
IS OVER THE LEEWARD ISLANDS ESPECIALLY THE VIRGIN ISLANDS AND
PUERTO RICO.  BROKEN TO OVERCAST LOW CLOUDS WITH RAIN ARE N OF
15N BETWEEN 60W-68W.  IN THE UPPER LEVELS...MIDDLE TO UPPER
LEVEL TROUGH OVER THE W ATLC TRAILS SWD OVER CUBA INTO THE W
CARIBBEAN. CONFLUENT FLOW INTO THE BASE OF THE TROUGH IS
PRODUCING STRONG SUBSIDENCE AND VERY DRY/STABLE CONDITIONS ALOFT
GENERALLY W OF A LINE FROM COSTA RICA TO HISPANIOLA. E OF THE
SAME LINE...A 60-110 KT SUBTROPICAL JET EXTENDS FROM JUST S OF
HISPANIOLA NEWD OVER THE LEEWARD ISLANDS AND INTO THE CENTRAL
ATLANTIC.  DIFFLUENCE ALONG THE JET AXIS IS PRODUCING A CANOPY
OF HIGH CLOUDINESS ACROSS MUCH OF THE E CARIBBEAN AND LESSER
ANTILLES.  EXPECT...THE RAIN AND SHOWERS OVER THE LEEWARD
ISLANDS TO TAPER OFF DURING THE NEXT 24 HOURS.  ALSO EXPECT SOME
AIRMASS CONVECTION OVER N VENEZUELA...AND N COLOMBIA WHILE THE
TRADEWINDS START TO GRADUALLY INCREASE.

ATLANTIC...
A 1018 MB HIGH IS N OF THE BAHAMAS NEAR 28N75W.  THE TAIL END
OF A COLD FRONT IS FURTHER E ALONG 32N58W 25N65W.  OVERCAST
MULTILAYERED CLOUDS WITH SCATTERED SHOWERS ARE WITHIN 120 NM E
OF FRONT N OF 27N.  A 1023 MB HIGH IS OVER THE CENTRAL ATLANTIC
NEAR 30N45W. IN THE UPPER LEVELS...A TROUGH-RIDGE-TROUGH PATTERN
PREVAILS OVER THE ATLANTIC WITH A TROUGH OVER THE W ATLANTIC
FROM THE CANADIAN MARITIMES SWD TO CUBA BETWEEN 60W-80W.  A
RIDGE IS OVER THE CENTRAL ATLANTIC BETWEEN 40W-60W WITH AXIS
ALONG 50W.  A TROUGH IS OVER THE E ATLANTIC N OF 15N BETWEEN
20W-40W BASICALLY FROM THE AZORES SWD TO JUST NW OF THE CAPE
VERDE ISLANDS. THE BULK OF THE ACTIVE WEATHER REMAINS FOCUSED
OVER THE CENTRAL ATLANTIC WHERE DIFFLUENT FLOW ALOFT E OF THE W
ATLANTIC TROUGH IS SPARKING A LINE OF SCATTERED SHOWERS/TSTMS
ALONG THE WEAKENING COLD FRONT.  THE OVERALL PATTERN WILL
ADVANCE EWD DURING THE NEXT 24 HOUR WITH THE BEST CHANCE OF
SHOWERS/TSTMS BEING N OF 18N BETWEEN 45W-55W BY FRI EVENING.

$$
FORMOSA



This weather bulletin was brought to you by:
www.nashvilleweather.net