[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 070603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT TUE 07 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...

TROPICAL STORM FRANCES WAS DOWNGRADED TO TROPICAL DEPRESSION AT
07/0300 UTC. FRANCES IS CENTERED NEAR 31.3N 84.6W AT 07/0600 UTC
MOVING NORTH-NORTHWEST AT 10 KT. MAXIMUM SUSTAINED WIND SPEED IS
30 KT WITH GUSTS TO 40 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS
985 MB. THIS THE LAST ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER. SEE STORM SUMMARIES UNDER AWIPS/WMO HEADERS
NFEDSCCNSS/WWUS37 KWBC FOR ADDITIONAL INFORMATION. ALTHOUGH MOST
OF THE DEEP CONVECTION IS NO LONGER IN THE GULF OF MEXICO
SCATTERED MODERATE/ISOLATED STRONG CONVECTION REMAINS OVER NE
FLORIDA...GEORGIA...AND SOUTH CAROLINA. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE STILL DE ELOPING OVER THE E
GULF N OF 24N E OF 87W.

HURRICANE IVAN IS CENTERED NEAR 11.3N 57.8W AT 07/0600 UTC WHICH
IS ABOUT 160 NM SE OF BARBADOS MOVING WEST AT 18 KT. MAXIMUM
SUSTAINED WIND SPEED REMAINS 90 KT WITH GUSTS TO 110 KT AND THE
ESTIMATED MINIMUM CENTRAL PRESSURE IS 963 MB. SEE LATEST NHC
PUBLIC ADVISORY OR NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT4/WTNT34 KNHC OR MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
UPPER LEVEL OUTFLOW REMAINS GOOD IN THE NORTHERN SEMICIRCLE. A
SMALL CLEARLY DEFINED EYE HAS REDEVELOPED. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 10N-14N BETWEEN 54W-59W. DEEP
CONVECTION WILL BE OVER BARBADOS AND TOBAGO EARLY THIS MORNING
MOVING OVER THE REMAINDER OF THE WINDWARD ISLANDS LATER TODAY.

...TROPICAL WAVES...
TROPICAL WAVE IN THE E ATLC IS ALONG 34W S OF 17N MOVING W 10
KT. GOOD ROTATION IS OBSERVED IN ASSOCIATION WITH THIS
WAVE...HOWEVER THE CONVECTION IS NOT CONCENTRATED AROUND THE
BROAD CENTER OF CIRCULATION. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 7N-18N BETWEEN
29W-38W.

TROPICAL WAVE OVER CENTRAL AMERICA IS ALONG 86W/87W S OF 17N
MOVING W 10-15 KT. WAVE IS GENERATING CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION OVER COSTA RICA...
NICARAGUA...AND HONDURAS. HOWEVER...THERE ARE NO SIGNS OF
FURTHER ORGANIZATION.

...ITCZ...

ITCZ IS CENTERED ALONG 10N10W 10N24W 6N40W 13N57W 7N60W.
SCATTERED MODERATE/STRONG CONVECTION IS OVER W AFRICA FROM
11N-14N BETWEEN 11W-17W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE FROM THE EQUATOR TO 8N BETWEEN 21W-44W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER LEVEL TROUGH EXTENDS SW FROM FRANCES TO A WEAK UPPER
LEVEL LOW OVER THE CENTRAL GULF NEAR 24N89W CONTINUING SW TO A
SECOND UPPER LEVEL LOW OVER THE SW GULF 24N95W TO OVER MEXICO
NEAR MEXICO CITY. MODERATE SUBSIDENCE AND DRY AIR ON THE S SIDE
OF THE TROUGH COVERS THE GULF EXCEPT IN THE STRAITS OF FLORIDA
AND THE FLORIDA PENINSULA ANTICYCLONIC FLOW AROUND MID/UPPER
LEVEL HIGH JUST E OF FRANCES IS ADVECTING MOISTURE N. OVER
MISSISSIPPI AND LOUISIANA STRONG SUBSIDENCE AND EVEN DRIER AIR
IS BEING PULLED S BY FRANCES MOVING INTO THE NW GULF.

CARIBBEAN SEA...
ANTICYCLONIC FLOW FROM THE MID/UPPER LEVEL HIGH E OF FRANCES IS
GENERATING NW OVER THE W CARIBBEAN W OF 78W. REMAINDER OF THE
CARIBBEAN IS UNDER THE INFLUENCE OF A LARGE UPPER LEVEL LOW OVER
THE E CARIBBEAN THAT HAS SHIFTED W OVER THE LAST 24 HOURS TO
NEAR 14N71W. ALTHOUGH THIS LOW IS RESPONSIBLE FOR THE DIMINISHED
OUTFLOW OVER IVAN EARLY YESTERDAY...WITH THE SHIFT W HAS ALLOWED
THE OUTFLOW OVER IVAN TO REDEVELOP. THE CURRENT PATTERN WILL
CONTINUE TO SHIFT WESTWARD DURING THE NEXT FEW DAYS ALLOWING THE
W CARIBBEAN TO BECOME MORE UNSETTLED WHILE IVAN MOVES INTO THE E
CARIBBEAN.

SUBTROPICAL ATLANTIC OCEAN...
LARGE MID/UPPER LEVEL RIDGE DOMINATES THE W ATLC EXTENDING FROM
E OF FRANCES TO 61W ALONG 32N. MID/UPPER LEVEL MOISTURE
ASSOCIATED WITH FRANCES CONTINUES TO STREAM E. OVER THE CENTRAL
ATLC...A DEEP LAYERED TROUGH IS N OF 26N FROM 38W-60W WITH AN
EMBEDDED DEEP LAYERED SHORTWAVE TROUGH ALONG 38W. AT THE
SURFACE...A COLD FRONT ENTERS THE CENTRAL ATLC NEAR 32N47W
EXTENDING W TO 31N55W WHERE IT CONTINUES AS A STATIONARY FRONT
OVER BERMUDA TO BEYOND 33N68W. A 1010 MB LOW...ASSOCIATED WITH
THE SHORTWAVE IS CENTERED NEAR 30N42W WITH A SURFACE TROUGH
EXTENDING SW ALONG 29N39W 24N45W TO 23N56W. TO THE E A MID/UPPER
LEVEL RIDGE AXIS EXTENDS FROM 24N37W NNE TO BEYOND 32N34W.
FURTHER S...A MID/UPPER LEVEL TROUGH UNDERCUTS THE W ATLC RIDGE
EXTENDING FROM 26N50W ALONG 23N61W TO HISPANIOLA NEAR 20N72W.
CLUSTERS OF SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 75 NM
ALONG THE TROUGH AXIS. STRONG SUBSIDENCE/DRY AIR IS LIMITING
SHOWERS/THUNDERSTORMS N OF THE TROUGH AXIS. OVER THE E ATLC...
THE NEAR STATIONARY UPPER LOW FROM THE PAST FEW DAYS IS LOSING
ITS DEFINITION AND NOW IS AN UPPER LEVEL TROUGH EXTENDING
THROUGH 32N17W TO 22N30W.

TROPICAL ATLANTIC...
MID/UPPER LEVEL HIGH IS MOVING OFF THE COAST OF W AFRICA NEAR
15N17W WITH A RIDGE AXIS EXTENDING W TO 15N35W. UPPER LEVEL HIGH
IS E OF IVAN NEAR 14N50W. MODERATE SUBSIDENCE COVERS THE CENTRAL
TROPICAL ATLC FROM 10N-20N BETWEEN 37W-49W.

$$
WALLACE


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