SPC MCD 201545
INZ000-KYZ000-MSZ000-TNZ000-201800-

SPC MESOSCALE DISCUSSION 1965 FOR WRN TN/WRN KY/SERN IND/NRN MS
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

THUNDERSTORMS WILL CONTINUE TO DEVELOP DURING THE NEXT FEW HOURS
OVER NRN MS INTO WRN PORTIONS OF TN/KY AND SERN IND. AREA WILL
CONTINUE TO BE MONITORED FOR A WW.

REGIONAL RADARS SHOW SEVERAL LINES OF STORMS HAVE INCREASED IN
INTENSITY DURING THE LAST HOUR FROM ERN IND SWWD INTO WRN KY/TN AND
NWRN MS WITHIN A WEAKLY CAPPED...MOIST AIR MASS. DEEP LAYER SHEAR
WILL SUPPORT ORGANIZED STORMS TODAY...WITH LEWPS/BOW STRUCTURES
BEING THE PRIMARY CONVECTIVE MODE...GIVEN UNIDIRECTIONAL SSWLY WIND
PROFILES. AS THE AIR MASS CONTINUES TO DESTABILIZE OVER THE NEXT
SEVERAL HOURS WITH MLCAPE EXPECTED TO RANGE FROM 1000-2000
J/KG...FURTHER STORM INTENSIFICATION IS EXPECTED. PRIMARY SEVERE
THREAT WILL BE FROM DAMAGING WINDS. HOWEVER...GIVEN THE STRENGTH
OF THE SPEED SHEAR...WITH SOME LOW-LEVEL DIRECTIONAL SHEAR...
EMBEDDED SUPERCELLS WILL BE POSSIBLE.


..PETERS.. 09/20/02

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
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ZCZC SPCSWOMCD ALL
ACUS11 KWNS 201751
SPC MCD 201751
MIZ000-201900-

SPC MESOSCALE DISCUSSION 1966 FOR SERN LOWER MI
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

AREA BEING MONITORED FOR POTENTIAL WW THIS AFTERNOON.
AN ISOLATED SEVERE STORM OVER MACOMB COUNTY MI WILL MOVE INTO
ONTARIO CANADA AROUND 18Z. VIS IMAGERY SHOWS CLEARING SKIES OVER
SERN MI IN THE WAKE OF THIS STORM...BUT EXTENSIVE CLOUDINESS OVER
NWRN OH/NRN IND WILL MOVE INTO SERN MI DURING THE NEXT FEW HOURS.
THESE CLOUDS SHOULD LIMIT THE AMOUNT OF ADDITIONAL DESTABILIZATION.
HOWEVER...GIVEN A MOIST AIR MASS /SURFACE DEWPOINTS AROUND 70 F/
ALREADY IN PLACE...AND INCREASING DEEP LAYER SHEAR WITH EJECTING
CENTRAL PLAINS UPPER TROUGH...STORMS OVER CENTRAL/SRN IND SHOULD
REMAIN STRONG TO SEVERE AS THEY MOVE INTO SERN MI LATER THIS
AFTERNOON.


..PETERS.. 09/20/02

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
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ZCZC SPCSWOMCD ALL
ACUS11 KWNS 201818
SPC MCD 201818
MSZ000-ALZ000-202000-

SPC MESOSCALE DISCUSSION 1967 FOR NRN MS AND NWRN AL
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

NUMEROUS TSTMS CONTINUE TO DEVELOP FROM WRN MS NNEWD INTO EXTREME
NRN MS. WE ARE MONITORING THE AREA FOR THE POSSIBILITY OF A WW.
LATEST WV IMAGERY REVEALS FULL-LATITUDINAL MOISTURE PLUME FROM THE
WRN GULF NWD THRU THE ENTIRE MS VALLEY REGION AND A MID-LVL SPEED
MAXIMUM FROM ECNTRL TX NNEWD INTO NWRN LA/SWRN ARK. OUT AHEAD OF
PRIMARY COLD FRONTAL BOUNDARY...POCKETS OF CLOUD-FREE AREAS ARE
ALLOWING DESTABILIZATION AND THIS TREND IS EXPECTED TO CONTINUE
THRU THE AFTERNOON HOURS. SFC TEMPERATURES FROM 85-90 DEGREES AND
SFC DEWPOINTS FROM 70-75 DEGREES IS LEADING TO A
MARGINALLY/MODERATELY UNSTABLE AIRMASS AROUND 1000 J/KG(100 MB
MLCAPE).

LATEST MOST REPRESENTATIVE VAD PROFILE (GWX) INDICATES SOME WEAK
BACKING IN THE 0-1 KM LAYER WITH MODEST 30-40 SSWLY FLOW JUST ABOVE
LEADING TO SFC-3KM SHEAR VALUES OF AROUND 30 KT. WITH WBZ HEIGHTS
AROUND 13KFT...THE PRIMARY SEVERE THREAT WILL BE STRONG DOWNBURST
WINDS AND BRIEF HEAVY DOWNPOURS OF RAINFALL. STRONGER DYNAMICAL
FORCING IS EXPECTED TO QUICKLY TRANSLATE ENEWD LATER THIS
AFTERNOON/EARLY EVENING...LIKELY ENDING SEVERE THREAT.

..NADEN.. 09/20/02

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
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ZCZC SPCSWOMCD ALL
ACUS11 KWNS 201837
SPC MCD 201837
INZ000-KYZ000-OHZ000-202000-

SPC MESOSCALE DISCUSSION 1968 FOR WRN KY/MUCH OF INDIANA/NWRN OH
CONCERNING...TORNADO WATCH 693...695...

PARAMETERS REMAIN SUPPORTIVE FOR TORNADOES FROM WRN KY INTO INDIANA
AND NWRN OH.

LATEST SURFACE ANALYSIS PLACES A SURFACE LOW OVER SWRN INDIANA WITH
A STRONG THERMAL GRADIENT/BOUNDARY EXTENDING ENEWD THROUGH CENTRAL
INDIANA TO W CENTRAL OH. SURFACE COLD FRONT EXTENDS SWWD FROM THE
LOW INTO WRN KY/TN. STRONG TO SEVERE STORMS EXTEND FROM CENTRAL
INDIANA SWWD INTO WRN TN WITH A RECENT INCREASE IN ACTIVITY OVER
WRN KY. LEWPS/BOW SEGMENTS WILL CONTINUE TO DEVELOP AND MOVE NEWD
THROUGH WRN KY...INDIANA AND EVENTUALLY NWRN OH...WITH THE STRENGTH
OF SPEED SHEAR AND 0-1 KM SRH UP TO 200 J/KG ALSO SUPPORTING
SUPERCELLS WITH ATTENDANT TORNADO THREAT.


..PETERS.. 09/20/02
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 201931
SPC MCD 201931
TNZ000-202100-

SPC MESOSCALE DISCUSSION 1969 FOR WRN AND MIDDLE TN
CONCERNING...SEVERE THUNDERSTORM WATCH 694...

PARAMETERS REMAIN FAVORABLE FOR DAMAGING WIND THREAT AS STORMS
SPREAD INTO MIDDLE TN DURING THE NEXT 1-2 HOURS.

BREAKS IN CLOUDS OVER MIDDLE TN HAVE ALLOWED SURFACE TEMPERATURES
TO RISE INTO THE UPPER 80S WITH SURFACE DEWPOINTS IN THE LOWER 70S
CONTRIBUTING TO MLCAPE AROUND 1000 J/KG. SSWLY MID/UPPER LEVEL
FLOW WILL CONTINUE TO INCREASE THIS AFTERNOON IN ADVANCE OF UPPER
TROUGH OVER THE CENTRAL U.S...AND REMAIN FAVORABLE FOR LEWPS/BOW
SEGMENTS.


..PETERS.. 09/20/02
NNNN
ZCZC SPCSWOMCD ALL;
ACUS11 KWNS 202003
SPC MCD 202003
KYZ000-OHZ000-202200-

SPC MESOSCALE DISCUSSION 1970 FOR N CENTRAL TO SWRN OH / CENTRAL KY
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

WW WILL BE ISSUED SOON FOR NORTH CENTRAL INTO SWRN OH TO CENTRAL
KY.

LINE OF STORMS CURRENTLY OVER SRN IND INTO WRN KY IS EXPECTED TO
MOVE NEWD INTO SWRN OH AND PORTIONS OF CENTRAL KY AROUND/OR AFTER
21Z...WITH ACTIVITY REMAINING STRONG TO SEVERE AS IT ENCOUNTERS
MOIST...WEAKLY CAPPED AIR MASS. AS STRONG MID/UPPER LEVEL FLOW
SPREADS ENEWD OVER THIS REGION...DEEP LAYER SHEAR/STRONG SPEED
SHEAR WILL BECOME FAVORABLE TO SUPPORT STRONG TO SEVERE STORMS.
UNIDIRECTIONAL SHEAR SHOULD FAVOR LEWPS/BOW SEGMENTS WITH DAMAGING
WINDS THE PRIMARY THREAT...BUT SUPERCELLS REMAIN LIKELY AS WELL.

..PETERS.. 09/20/02

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
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ZCZC SPCSWOMCD ALL
ACUS11 KWNS 202043
SPC MCD 202043
TNZ000-202200-

SPC MESOSCALE DISCUSSION 1971 FOR MIDDLE TN
CONCERNING...SEVERE THUNDERSTORM WATCH 694...

A NEW WW MAY BE NEEDED IN THE NEXT 1-2 HOURS FOR MUCH OF MIDDLE TN.
REGIONAL RADARS SHOW A BROKEN LINE OF STORMS FROM ROBERTSON COUNTY
TN SSWWD INTO NERN MS. CELL MOTION WITHIN THIS LINE IS TO THE NE
AT 30-40 KT...RESULTING IN NERN MS ACTIVITY TO MOVE INTO MIDDLE TN
BETWEEN 21-22Z. AS STRONG SWLY MID/UPPER LEVEL FLOW SPREADS EWD
OVER MIDDLE TN...DEEP LAYER SHEAR WILL BECOME MORE FAVORABLE FOR
ORGANIZED STORMS. DEEP UNIDIRECTIONAL SWLY FLOW WILL RESULT IN
LEWPS/BOW SEGMENTS BEING THE PRIMARY CONVECTIVE MODE...THOUGH
SUPERCELLS WILL BE POSSIBLE AS WELL.


..PETERS.. 09/20/02
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 202121
SPC MCD 202121
MIZ000-OHZ000-210000-

SPC MESOSCALE DISCUSSION 1972 FOR SERN LOWER MI / NWRN OH...
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...

THUNDERSTORMS ARE FORECAST TO CONTINUE MOVING ACROSS NWRN OH AND
SERN LOWER MI. SEVERE THREAT WILL PERSIST FOR A FEW HOURS...AND
THUS WW WILL BE ISSUED SHORTLY.

LINE OF THUNDERSTORMS ALONG THE NERN IN / NWRN OH BORDER INVOF
SURFACE MESOLOW / PRESSURE RISE-FALL COUPLET IS FORECAST TO
CONTINUE MOVING NEWD ACROSS NWRN OH. MEANWHILE...MORE ISOLATED
STORMS CONTINUE TO MOVE NNEWD AHEAD OF THIS LINE. ALTHOUGH
INSTABILITY IS SOMEWHAT LIMITED ACROSS THIS REGION /AROUND 500 J/KG
MEAN-LAYER CAPE/ STRONG DEEP-LAYER WIND FIELD ASSOCIATED WITH
APPROACHING SHORT WAVE TROUGH SUPPORTS A CONTINUED SEVERE THREAT --
MAINLY IN THE FORM OF STRONG / DAMAGING WINDS AND ISOLATED
TORNADOES.



..GOSS.. 09/20/02

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 202337
SPC MCD 202337
KYZ000-OHZ000-210200-

SPC MESOSCALE DISCUSSION 1973 FOR CNTRL OH/CNTRL KY
CONCERNING...SEVERE THUNDERSTORM WATCH 696

THE SEVERE THREAT APPEARS TO BE GRADUALLY DECREASING AS THE
ATMOSPHERE STABILIZES. LATEST SFC OBJECTIVE ANALYSIS SHOWS MIXED
LAYER CAPE VALUES LESS THAN 1000 J/KG. NEVERTHELESS...VERTICAL
SHEAR ON THE ORDER OF 40 KTS SUGGESTS THERE IS STILL A THREAT FOR
DAMAGING WINDS. THE HIGHEST RISK OF SEVERE WEATHER WILL BE NORTH OF
THE OH RIVER...WHERE SFC TEMPS AHEAD OF THE FRONT ARE IN THE 80S
WITH DEWPOINTS IN THE MID TO UPPER 60S.


..TAYLOR.. 09/20/02

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 210047
SPC MCD 210047
ALZ000-GAZ000-TNZ000-210300-

SPC MESOSCALE DISCUSSION 1974 FOR MIDDLE AND ERN TN / NRN AL / NWRN
GA...
CONCERNING...SEVERE THUNDERSTORM WATCH 0698...

THUNDERSTORMS CONTINUE MOVING ACROSS THE ERN 2/3 OF WW WHERE A
THREAT FOR MAINLY DAMAGING WINDS CONTINUES.

LATEST OBJECTIVE ANALYSES SHOW INSTABILITY AXIS /500 TO 1000 J/KG
MEAN-LAYER CAPE/ EXTENDING FROM NRN AL NWD TO THE CUMBERLAND
PLATEAU OF ERN TN -- AHEAD OF MAIN LINE OF CONVECTION. AREA VWPS
CONTINUE TO SHOW MODERATELY STRONG DEEP-LAYER WIND PROFILE
SUGGESTING A CONTINUED THREAT FOR MAINLY DAMAGING WINDS AS STORMS
MOVE EWD THROUGH INSTABILITY AXIS.


..GOSS.. 09/21/02

...PLEASE SEE WWW.SPC.NOAA.GOV/ FOR GRAPHIC PRODUCT...
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