[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291122
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN OCT 29 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 48 S OF 15N MOVING W 10 TO 15 KT. THIS
WAVE REMAINS RATHER LOW AMPLITUDE WITH LITTLE CURVATURE NOTED IN
SATELLITE IMAGERY. PLACEMENT IS BASED ON CONTINUITY. DEEP
CONVECTION ASSOCIATED WITH THIS WAVE REMAINS MINIMAL.

TROPICAL WAVE IS MOVING QUICKLY THROUGH THE EAST TO CENTRAL
CARIBBEAN ALONG 69W MOVING W NEAR 20 KT. THIS WAVE REMAINS WELL
DEFINED WITH CLEAR CYCLONIC CURVATURE NOTED IN THE LOW TO MID
CLOUD FIELD...BETWEEN HISPANIOLA AND SOUTH AMERICA.
SHOWERS/TSTMS HAVE INCREASED A BIT OVER THE LAST SEVERAL HOURS
WITH MODERATE/ISOLATED STRONG CONVECTION NOW NOTED FROM 13N-18N
BETWEEN 68W-74W. SOME SLOW DEVELOPMENT IS POSSIBLE WITH THIS
SYSTEM OVER THE NEXT COUPLE OF DAYS.

A TROPICAL WAVE IS ALONG 79W S OF 18N MOVING W 10 TO 15 KT. THIS
WAVE HAS BECOME DIFFICULT TO LOCATE OVERNIGHT AND IS NEARING THE
COLD FRONT THAT RECENTLY ENTERED THE NW CARIBBEAN. ISOLATED
SHOWERS/TSTMS NOTED WITHIN 150 NM EITHER SIDE OF THE AXIS N OF
13N. TO THE SOUTH OF 13N...A CLUSTER OF STRONG CONVECTION IS
SEEN IN THE SW CARIBBEAN OFF THE COAST OF PANAMA...LIKELY
ENHANCED BY THE ITCZ.

 ...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N15W 8N30W 8N44W 9N55W TO THE
SOUTH AMERICAN COAST NEAR 9N61W. SEVERAL CLUSTERS OF SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION SEEN WITHIN 200NM OF
EITHER SIDE OF THE AXIS BETWEEN 17W-45W. SCATTERED MODERATE ALSO
SEEN OFF THE NE SOUTH AMERICA COAST FROM 7N-12N BETWEEN
55W-61W.

...DISCUSSION...
THE GULF OF MEXICO...
SURFACE HIGH PRESSURE FROM MEXICO AND SRN TEXAS HAS SUCCESSFULLY
BUILT INTO THE GULF BEHIND OUR RECENT COLD FRONT
PASSAGE...PRODUCING 10-15 KT NW/N FLOW ACROSS THE AREA. THE NRN
GULF IS EXPERIENCING CLEAR SKIES WITH OFFSHORE FLOW...WHILE
SCATTERED TO BROKEN COOL AIR STRATOCUMULUS CLOUDS REMAIN
VISIBLE S OF 27N. ZONAL FLOW ALOFT CONTINUES TO ADVECT VERY DRY
MID TO UPPER AIR E ACROSS THE GULF IN WAKE OF THE FRONTAL
SYSTEM. THE POSTFRONTAL WINDS AND SEAS WILL CONTINUE TO
GRADUALLY RELAX THROUGH TONIGHT AND GAIN MORE OF AN EASTERLY
COMPONENT AS HIGH PRESSURE DEVELOPS OVER THE CENTRAL GULF COAST.

THE CARIBBEAN SEA...
FRONTAL BOUNDARY...NOW STATIONARY...CONTINUES TO DOMINATE THE
WEATHER OVER THE NW CARIBBEAN WITH THE 29/0900 UTC PLACEMENT
BETWEEN CENTRAL CUBA AND BELIZE. AN ASSOCIATED CLUSTER OF
MODERATE CONVECTION IS HOVERING OVER THE GULF OF HONDURAS. THIS
IS ALSO BEING SUPPORTED BY UPPER DIFFLUENT AIR...BETWEEN THE
PRONOUNCED UPPER TROUGHING EXTENDING S FROM THE EAST COAST AND
UPPER RIDGING EXTENDING THROUGH HONDURAS FROM ITS CENTER JUST
OFFSHORE SALSA BRAVA COSTA RICA. A SMALL SHORTWAVE UPPER TROUGH
IS ALSO ALIGNED FROM SE TO NW THROUGH THE NW CARIBBEAN...THAT
HAS ISOLATED SHOWERS/TSTMS ON THE PVA SIDE OF THE AXIS JUST S OF
JAMAICA. THE TROPICAL WAVE MOVING THROUGH THIS AREA ALSO LIKELY
ENHANCING THE ACTIVITY. AN UPPER HIGH IS NEAR THE TURKS AND
CAICOS ISLANDS THAT IS AFFECTING THE NRN CARIBBEAN. UPPER
DIFFLUENCE BETWEEN THIS FEATURE AND AN UPPER LOW JUST S OF THE
ABC ISLANDS IS HELPING TO SUPPORT THE CONVECTION NEAR THE
TROPICAL WAVE ALONG 69W. THE SHOWERS AND TSTMS ASSOCIATED WITH
THIS WAVE WILL MOVE ACROSS THE CENTRAL CARIBBEAN THROUGH MONDAY
WHILE THE FRONT OVER THE NW PORTION GRADUALLY BECOMES
DIFFUSE.

THE ATLANTIC OCEAN...
AS OF 29/0900 UTC A COLD FRONT IS OVER THE W ATLC EXTENDING
THROUGH CUBA AND THE BAHAMAS TO NEAR 32N69W. NUMEROUS
MODERATE/ISOLATED STRONG CONVECTION ASSOCIATED WITH THE FRONT
NOW NOTED FROM 24N-30N BETWEEN 68W-74W...WHICH SEEMS TO BE
ALIGNED WITH A PREFRONTAL TROUGH THAT HAS REESTABLISHED ITSELF
OVER THE LAST FEW HOURS. THE INTERACTION BETWEEN THE FRONT WITH
A 1023 MB HIGH NEAR 33N50W IS PRODUCING GUSTY SW FLOW E OF THE
FRONT TO 25 KT...THOUGH THE PREFRONTAL GALE HAS BEEN ALLOWED TO
EXPIRE. MUCH STRONGER GRADIENT NOTICED WELL N OF THE AREA OFF
THE MID ATLANTIC COAST. THE FRONT IS ASSOCIATED WITH UPPER
TROUGHING EXTENDING S THROUGH THE EAST COAST...THAT IS ADVECTING
VERY DRY MID TO UPPER AIR OFF THE CAROLINAS THROUGH FLORIDA. A
WELL DEFINED UPPER HIGH IS ABOUT 400NM NE OF THE LEEWARD ISLANDS
NEAR 24N58W...THAT HAS ABUNDANT DRY AIR ROTATING AROUND IT. E OF
THIS UPPER HIGH LIES AN UPPER TROUGH THAT HAS ITS OLD ASSOCIATED
FRONTAL BOUNDARY ALONG 32N33W 27N40W 25N51W. THERE IS STILL A
LINE OF LOW CLOUDS ASSOCIATED WITH THIS OLD BOUNDARY...BUT THE
DRY STABLE ENVIRONMENT SURROUNDING IT IS PREVENTING DEEP
CONVECTION. MUCH OF THE E ATLC N OF 15N BETWEEN AFRICA AND 40W
ALSO IN A DRY/STABLE ENVIRONMENT WITH SCATTERED STRATOCUMULUS
CLOUDS. A BROAD UPPER LOW IS SPINNING JUST N OF THE CANARY
ISLANDS WITH A WEAK SURFACE LOW NEAR THE WRN CANARIES AT 28N19W.
AN ELONGATED UPPER TROUGH EXTENDING WSW THROUGH THE DEEP TROPICS
IS SHEARING THE HIGH CLOUDS FROM THE ITCZ CONVECTION TO THE
E/NE.

$$
WILLIS




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