[Tropical] Tropical Weather Discussion

[Nashville EMWIN]

AXNT20 KNHC 111210
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT 11 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
1145 UTC.

...SPECIAL FEATURE...

HURRICANE IVAN CENTERED NEAR 17.7N 78.4W OR ABOUT 60 MILES S OF
MONTEGO BAY JAMAICA AT 11/1200 UTC MOVING WNW AT 9 KT. MAXIMUM
SUSTAINED WIND SPEED IS 135 KT WITH GUSTS TO 165 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 923 MB. SEE LATEST NHC PUBLIC
ADVISORY OR NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT4/WTNT34 KNHC OR MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
SATELLITE IMAGERY INDICATES THAT IVAN REMAINS WELL ORGANIZED.
THE EYE REMAINS DISTINCT AND TOOK A JOG TO THE W OVERNIGHT BUT
HAS RETURNED TO A WNW TRACK. CLOUD TOP TEMPERATURES REMAIN IN
THE -70 TO -80 CELSIUS RANGE WITHIN 90 NM OF THE CENTER.
SCATTERED STRONG CONVECTION IS WITHIN 120/140 NM OF THE CENTER
IN THE SE SEMICIRCLE AND WITHIN 90 NM IN THE NW SEMICIRCLE.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NE OF THE
SYSTEM FROM 19N-22N BETWEEN 73W-78W INCLUDING W HAITI AND E
CUBA. THE UPPER LEVELS...IVAN CONTINUES TO BE FLANKED A MID/
UPPER LEVEL HIGH TO THE NW AND A BROAD MID/UPPER LEVEL HIGH TO
THE E. DUE TO THE MID/UPPER LEVEL TROUGH MOVING W OF THE YUCATAN
PENINSULA...THERE IS A SLIGHT INDICATION OF UPPER LEVEL SHEAR TO
NW BUT OVERALL THERE IS GOOD UPPER LEVEL OUTFLOW. AN UPPER
TROUGH EXTENDING OVER THE BAHAMAS IS FORCING STRONG SUBSIDENCE
ACROSS THE BAHAMAS TO OVER CUBA. CONDITIONS REMAIN FAVORABLE FOR
FURTHER STRENGTHENING.

...TROPICAL WAVES...

TROPICAL WAVE OVER THE E ATLC OVER THE CAPE VERDE ISLANDS IS
ALONG 23W S OF 21N MOVING W 10-15 KT. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 90 NM OF 24.5W
FROM 13N-20N.

CENTRAL ATLC TROPICAL WAVE IS ALONG 45W S OF 18N MOVING W 10-15
KT. THE WAVE IS BROAD AND LOW-AMPLITUDE WITH ASSOCIATED
CONVECTION BECOMING BETTER ORGANIZED. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 140 NM OF LINE
FROM 11N41W-15N46W-15N51W.

TROPICAL WAVE LOCATED JUST E OF THE LEEWARD/WINDWARD ISLANDS
ALONG 60W S OF 20N MOVING W 10 KT. A 1009 MB LOW IS ALONG THE
WAVE NEAR 16N. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 45
NM RADIUS OF 16N59.5W. SCATTERED SHOWERS ARE FROM 11N-19N
BETWEEN 56W-63W INCLUDING THE WINDWARD ISLANDS.

...ITCZ...

ITCZ AXIS EXTENDS ALONG 16N10W 8N26W 11N43W 13N61W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS OFF THE COAST OF AFRICA
WITHIN 150 NM FROM 7N-11N AND WITHIN 45/60 NM OF 20.5N FROM
13N-16N. CLUSTERS OF SIMILAR CONVECTION ARE FROM 3N-13N BETWEEN
23W-30W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN
FROM 3N-8N BETWEEN 8W-22W AND FROM 4N-10N BETWEEN 41W-50W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH AXIS OVER THE E UNITED STATES EXTENDS JUST
E OF THE MISSISSIPPI VALLEY INTO THE NW GULF. A STRONG UPPER
LEVEL HIGH OVER MEXICO WITH THE ASSOCIATED UPPER LEVEL RIDGE
AXIS EXTENDING N OVER THE CENTRAL U.S. IS FORCING STRONG
SUBSIDENCE S INTO THE NW GULF LIMITING ANY SHOWER ACTIVITY. THE
PERSISTENT SURFACE TROF...FROM THE SE GEORGIA ACROSS THE FLORIDA
PANHANDLE INTO THE NE GULF TO NEAR 27N90W...CONTINUES TO TO
BRING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE NE
GULF. ADDITIONALLY...AN UPPER LEVEL TROUGH RETROGRADING ACROSS
THE BAY OF CAMPECHE IS PRODUCING INCREASING
SHOWERS/THUNDERSTORMS OVER S S GULF INTO MEXICO. THE SMALL UPPER
LEVEL HIGH NW OF HURRICANE IVAN CENTERED OVER W CUBA HAS A RIDGE
AXIS EXTENDING NNE ACROSS CENTRAL FLORIDA INTO THE W ATLC AND IS
ENHANCING THE SHOWERS ASSOCIATED WITH THE SURFACE TROUGH JUST TO
ITS W.

CARIBBEAN...
THE MAJOR FEATURE OVER THE CARIBBEAN IS HURRICANE IVAN WHICH IS
STILL S OF JAMAICA. ASSOCIATED RAINBANDS AND CONTINUE TO AFFECT
W HAITI...SE CUBA AND MOVING OVER THE CAYMAN ISLANDS. THE E
CARIBBEAN IS UNDER MODERATE/STRONG SUBSIDENCE IN THE MID-UPPER
LEVELS EFFECTIVELY CAPPING SIGNIFICANT CLOUDS/CONVECTION EXCEPT
IN ASSOCIATION WITH THE APPROACHING TROPICAL WAVE. A STRONG
MID/UPPER LEVEL HIGH E OF IVAN WITH A RIDGE AXIS EXTENDING E TO
16N57W.

SUBTROPICAL ATLANTIC...
THE BIG FEATURE OVER THE SUBTROPICAL ATLC IS THE MID-OCEANIC
UPPER TROUGH ACROSS THE ATLC FROM THE NE ATLC 550 NM WNW OF THE
CANARY ISLANDS NEAR 32N26W SW TO A SMALL UPPER LOW NEAR 29N32W
THEN WNW TO A SECOND UPPER LEVEL LOW NEAR 31N48W TO A VERY LARGE
UPPER LOW NEAR 29N64W THEN SW TO A SMALLER MID/UPPER LOW NEAR
26N73W. THE LARGE UPPER LOW NEAR 64W IS RETROGRADING WESTWARD
AND ERODING THE MID/UPPER LEVEL RIDGE WHICH HAS PERSISTED OVER
THE W ATLC FOR SEVERAL DAYS. STRONG SUBSIDENCE AND DRY AIR WITH
THE UPPER LOW IS SPREADING WESTWARD AND AND IS PUSHING SW ACROSS
CUBA INTO THE NW CARIBBEAN. AT THE SURFACE... SUBTROPICAL RIDGE
REMAINS DISRUPTED OVER THE CENTRAL ATLC BY THE REMNANTS OF A
SURFACE TROUGH THAT WAS ALONG 55W. A WEAK RIDGE EXISTS ACROSS
THE W ATLC FROM BERMUDA W TO CENTRAL FLORIDA.

TROPICAL ATLANTIC...
TROPICS ARE DOMINATED BY A PAIR OF UPPER LEVEL HIGHS...ONE OFF
THE COAST OF AFRICA NEAR 14N17W AND A SECOND NEAR 16N43W.
MODERATE SUBSIDENCE AND DRY AIR IS SUPPRESSING SHOWER ACTIVITY
ACROSS THE ENTIRE E ATLC.

$$
WALLACE


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