[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291732
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN APR 29 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
1700 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 3N20W 2N30W EQ38W AND INTO NE
BRAZIL NEAR 3S45W. ISOLATED MODERATE TO STRONG CONVECTION IS OFF
THE COAST OF LIBERIA FROM 3N-7N BETWEEN 8W-16W. SCATTERED
MODERATE IS FROM 4N-7N BETWEEN 20W-28. NUMEROUS
MODERATE/ISOLATED STRONG ALSO NOTED FROM 2N-5N BETWEEN 31W-40W.

...DISCUSSION...

GULF OF MEXICO...
WEATHER CONDITIONS ACROSS THE GULF REMAIN FAIRLY QUIET THIS
AFTERNOON WITH SFC RIDGING DOMINATING. AS OF 29/1500 UTC A 1024
MB HIGH WAS LOCATED OFF THE LOUISIANA COAST NEAR 29N92W.
ASSOCIATED CLEAR SKIES...LIGHT N TO NE WINDS...AND SEAS
GENERALLY BELOW 3' ARE NOTED OVER THE GULF WATERS E OF 90W.
SCATTERED CLOUD COVER IS OVER MUCH OF THE WRN GULF WITH A BIT
MORE MOISTURE AVAILABLE AROUND THE S AND SW PORTION OF THE SFC
RIDGE. A WEAK SFC TROUGH HAS CONTINUED TO MOVE W THROUGH THE SW
GULF...NOW THROUGH THE BAY OF CAMPECHE ALONG 22N93W 18N93W.
E/ESE WINDS TO 20 KT NOTED E OF THE TROUGH TO THE YUCATAN
PENINSULA. THESE WINDS HAVE ALLOWED SHORT PERIOD WIND WAVES TO
BUILD TO THE 3-5' RANGE IN THE ERN BAY OF CAMPECHE...WHICH IS
GENERALLY THE ONLY SPOT IN THE GULF THAT HAS SEAS OVER 3' AND
WINDS GREATER THAN 15KT. UPPER FLOW REMAINS NEARLY ZONAL WHILE
MID LEVEL FLOW IS MORE ANTICYCLONIC. NW FLOW AROUND THE ERN
PORTION OF THIS MID LEVEL RIDGE IS ADVECTING VERY DRY AIR INTO
THE NE GULF. SFC HIGH WILL DRIFT SLOWLY E IN THE NRN GULF OVER
THE NEXT COUPLE OF DAYS...KEEPING CONDITIONS FAIRLY TAME THROUGH
EARLY WEEK. MOISTURE CONTENT WILL CONTINUE TO BE GREATEST WRN
PORTION WITH SE FLOW.

CARIBBEAN SEA...
MODERATE TO FRESH TRADE FLOW CONTINUES TO ADVECT TYPICAL PATCHES
OF LOW LEVEL MOISTURE WWD ACROSS THE BASIN. THE MOST
CONCENTRATED OF THESE PATCHES IS BETWEEN NICARAGUA AND JAMAICA
WHERE SOME LOW LEVEL CONFLUENCE IS NOTED. SIMILAR AREAS OF LOW
LEVEL CLOUDINESS/SHOWERS EMBEDDED IN THE TRADE FLOW ARE NOTED
NEAR PUERTO RICO...WINDWARD ISLANDS...AND ERN CARIB.
ANTICYCLONIC FLOW DOMINATES MUCH OF THE UPPER LEVELS OVER THE
CARIB AROUND A RIDGE THAT EXTENDS WNW THROUGH NRN SOUTH AMERICA.
SOME WEAK UPPER TROUGHING EVIDENT IN THE FAR NE PORTION WHICH
MAY BE ENHANCING SOME OF THE AFOREMENTIONED TRADE SHOWERS.
MODERATE TO FRESH TRADE WINDS EXPECTED OVER THE CARIB THE NEXT
FEW DAYS AS HIGH PRES BUILDS N OF THE AREA.

ATLANTIC...
WEAK SFC HIGH PRES IS BUILDING INTO THE THE WRN ATLC BEHIND THE
FRONTAL TROUGH THAT ENTERS THE AREA NEAR 31N72W AND CONTINUES SW
TO NEAR THE CENTRAL COAST OF CUBA NEAR 22N78W. SCATTERED SHOWERS
WITH A FEW ISOLATED TSTMS ARE WITHIN 250NM E OF THE TROUGH...AND
ALSO IN THE PREFRONTAL CONFLUENT ZONE NOTED N OF 25N BETWEEN
61W-68W. THIS ACTIVITY ALSO BEING SUPPORTED BY THE UPPER
DIFFLUENT ZONE BETWEEN THE UPPER TROUGHING OFF THE EAST COAST
AND RIDGING EXTENDING NE THROUGH THE CENTRAL ATLC. ON THE
CONTRARY...VERY DRY/STABLE AIR IS BEING ADVECTED INTO THE WRN
ATLC IN WAKE OF THE DEEP LAYER TROUGHING. THE OTHER INTERESTING
FEATURE IN THE WRN ATLC IS THE SMOKE PLUME AFFECTING N AND
CENTRAL FLORIDA AND ADJACENT ATLC WATERS...DOWNSTREAM FROM THE
LARGE WILDFIRES IN SE GEORGIA. OTHERWISE THE REMAINDER OF THE
ATLC DISCUSSION AREA IS DOMINATED BY THE SRN PERIPHERY OF A 1030
MB SFC HIGH SW OF THE AZORES NEAR 36N36W. THIS IS PRODUCING
WIDESPREAD FAIR WEATHER AND MODERATE TO FRESH TRADES E OF 55W.
WEAK HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE WRN ATLC
WHILE MUCH STRONGER/LARGER HIGH PRESSURE REMAINS IN CONTROL OF
THE ERN ATLC. CONFLUENCE BETWEEN THESE TWO HIGHS WILL SUPPORT A
SLOWLY DYING FRONTAL TROUGH NE OF THE SE BAHAMAS OVER THE NEXT
DAY OR SO.

$$
WILLIS




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