[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 081205
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED 08 SEP 2004

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLC 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.

...SPECIAL FEATURES...

HURRICANE IVAN IS CENTERED NEAR 12.5N 65.5W AT 08/1200 UTC WHICH
IS ABOUT 190 MILES E OF BONAIRE. IVAN CONTINUES TO MOVE WEST AT
14 KT. MAXIMUM SUSTAINED WIND SPEED IS 120 KT WITH GUSTS TO 145
KT AND THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 946 MB. SEE
LATEST NHC PUBLIC ADVISORY OR NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC OR MIATCMAT4/WTNT24 KNHC
FOR MORE DETAILS.

 IVAN IS GOING THROUGH CONCENTRIC EYEWALL
CYCLES WITH A CLEARLY DEFINED PIN-HOLE EYE. UPPER-LEVEL OUTFLOW
LOOKS BETTER TONIGHT WITH A LITTLE RESTRICTION TO THE WEST DUE
TO AN UPPER LEVEL LOW OVER THE W CARIBBEAN. HOWEVER AS THIS LOW
CONTINUES TO RETREAT WESTWARD...IT WILL LEAVE IVAN WITHIN A
DIVERGENT/FAVORABLE UPPER LEVEL PATTERN. CURRENTLY...NUMEROUS
STRONG CONVECTION IS WITHIN 60 NM OF THE CENTER IN THE SW
QUADRANT. OUTER RAINBANDS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION COVER THE AREA FROM 10N-16N BETWEEN 60W-69W INCLUDING
TRINIDAD...TOBAGO...AND THE WINDWARD ISLANDS.

...TROPICAL WAVES...
TROPICAL WAVE IN THE FAR E ATLC IS ALONG 24W/25W S OF 17N OVER
THE CAPE VERDE ISLANDS MOVING W 10 KT. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 90 NM OF 25W FROM
7N-12N.

TROPICAL WAVE IN THE CENTRAL ATLC IS ALONG 40W/41W S OF 18N
MOVING W 10 KT. SCATTERED CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION ARE FROM 11N-18N BETWEEN 39W-45W.

TROPICAL WAVE OVER CENTRAL AMERICA IS OVER THE YUCATAN PENINSULA
AND GUATEMALA ALONG 91W S OF 18N MOVING W 10 KT. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS S OF 20N FROM 91W TO 93W.
IN THE BAY OF CAMPECHE.

...ITCZ...
ITCZ AXIS IS ALONG 10N10W 7N26W 9N36W 6N48W 12N60W THEN BECOMES
DISTORTED BY HURRICANE IVAN. LARGE CLUSTERS OF SCATTERED STRONG
CONVECTION COVER THE AREA FROM 3N-11N BETWEEN 23W-37W. SCATTERED
MODERATE CONVECTION IS WITHIN 60 NM OF LINE FROM 8N38W-6N45W.

...DISCUSSION...

GULF OF MEXICO AND W ATLANTIC...
THE UPPER LEVEL LOW ASSOCIATED WITH FRANCES IS NOW MOVING NE
OVER THE APPALACHIA MOUNTAINS WITH A NEAR STATIONARY MID/UPPER
LEVEL TROUGH TRAILING SW ACROSS THE MISSISSIPPI DELTA INTO
THE W GULF ALONG 30N90W TO 25N95W. STRONG SUBSIDENCE AND DRY
SURFACE AIR IS ACROSS THE CENTRAL U.S. OVER ALABAMA AND SE INTO
THE NW GULF. A COLD FRONT ENTERS THE GULF OVER THE FLORIDA
PANHANDLE NEAR 31N86W EXTENDING WSW ALONG 28N93W TO TO INLAND
DOVER THE MEXICAN COAST NEAR 25N98W. SCATTERED SHOWERS ARE ALONG
THE FRONT. FURTHER E...MID-UPPER LEVEL RIDGE EXTENDS FROM A
MID/UPPER LEVEL HIGH LOCATED E OF JACKSONVILLE NEAR 30N79W SW
ACROSS CENTRAL FLORIDA TO THE YUCATAN PENINSULA. THIS PATTERN IS
PRODUCING MODERATE SUBSIDENCE AND SURFACE DRY AIR OVER THE
CENTRAL GULF SUPPRESSING DEEP CONVECTION. ABUNDANT MOISTURE IS
BEING PULLED S OVER THE W ATLC AND THE FLORIDA PENINSULA INTO
THE STRAITS OF FLORIDA AND THE NW CARIBBEAN. THE W GULF UPPER
TROUGH IS EXPECTED TO DRIFT WESTWARD AND WEAKEN OVER THE NEXT 24
HOURS WHILE THE RIDGE OVER FLORIDA BUILDS WESTWARD IN ITS WAKE.

CARIBBEAN SEA...
THE BIGGEST FEATURE OVER THE CARIBBEAN IS HURRICANE IVAN WHICH
IS IN THE E CARIBBEAN MOVING AWAY FROM THE WINDWARD ISLANDS. SEE
SPECIAL FEATURES ABOVE FOR MORE ON IVAN. ELSEWHERE...LARGE MID/
UPPER LEVEL LOW S OF JAMAICA NEAR 15N78W CONTINUES TO CREATE
UNSETTLED WEATHER OVER A GOOD PORTION OF THE PERIMETER OF THE
CARIBBEAN. THIS CYCLONIC FLOW COUPLED WITH THE RIDGE OVER THE
YUCATAN IS CREATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
FROM E CUBA AND HAITI. SCATTERED STRONG CONVECTION IS WITHIN 75
NM OF LINE FROM 10N80W TO INLAND OVER NICARAGUA NEAR 12N85W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S
OF 12N FROM 72W TO 78W. THE UPPER LOW WILL CONTINUE TO
RETROGRADE SLOWLY WESTWARD OVER THE NEXT 36 TO 48 HOURS ALLOWING
MORE UNSETTLED WEATHER OVER THE W CARIBBEAN TO MIGRATE ACROSS
THE YUCATAN PENINSULA INTO THE S GULF OF MEXICO.

CENTRAL/EASTERN ATLANTIC...
THERE HAS BEEN LITTLE CHANGE TO THE LARGE SCALE PATTERN OVER THE
REMAINDER OF THE ATLC WITH A MID/UPPER LEVEL TROUGH...RIDGE...
TROUGH PATTERN. TROUGH OVER THE CENTRAL ATLC IS N OF 24N FROM
38W-68W...RIDGE AXIS EXTENDING FROM AN UPPER LEVEL HIGH IN THE
TROPICAL ATLC NEAR 18N35W N TO BEYOND 32N31W...AND TROUGH OVER
THE E ATLC N OF 16N E OF 25W TO THE COAST OF AFRICA. ASSOCIATED
STATIONARY FRONT ENTERS THE CENTRAL ATLC NEAR 33N46W EXTENDING W
ALONG 31N55W TO 33N62W AND A 1011 MB SURFACE LOW IS CENTERED
NEAR 33N39W WITH A SURFACE TROUGH EXTENDING SW FROM 31N36W ALONG
25N42W TO 21N52W. THIS GENERAL UPPER LEVEL PATTERN WILL REMAIN
OVER THE NEXT COUPLE OF DAYS WITH AN UPPER LEVEL LOW BECOMING
CUT OFF OVER THE CENTRAL/WESTERN ATLC STARTING IN 36 TO 48
HOURS.

TROPICAL ATLANTIC...
A LOW AMPLITUDE MID/UPPER LEVEL HIGH IS JUST E OF THE WINDWARD
ISLANDS NEAR 12N57W WITH A RIDGE AXIS EXTENDING N TO 23N53W. A
SECOND UPPER LEVEL HIGH IN THE E TROPICAL ATLC NEAR 18N35W.

$$
WALLACE





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