Mesoscale Discussion 342

Issued

Mar 23, 2012, 11:16 PM EDT (03:16 UTC)

Expired

Mar 24, 2012, 12:45 AM EDT

In force

89 min

Issued by

the Storm Prediction Center

The Louisville radar (KLVX), 72 km from the middle of the area, began a volume at 03:17 UTC, the scan nearest the moment this went out.

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406 
ACUS11 KWNS 240317
SWOMCD
SPC MCD 240316
OHZ000-KYZ000-TNZ000-GAZ000-INZ000-240445-

MESOSCALE DISCUSSION 0342
NWS STORM PREDICTION CENTER NORMAN OK
1016 PM CDT FRI MAR 23 2012

AREAS AFFECTED...ERN/SERN IND...SWRN OH...CENTRAL KY AND ERN TN

CONCERNING...TORNADO WATCH 103...

VALID 240316Z - 240445Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 103 CONTINUES.

...WW 103...
TRENDS IN OBJECTIVE ANALYSES INDICATED SUBSTANTIAL REDUCTION OF
INSTABILITY FROM N-S ACROSS MUCH OF WW 103 AS THE AIR MASS HAS
CONTINUED TO COOL WITH LOSS OF DAY TIME HEATING AND HAS BEEN
AFFECTED BY CONVECTIVE OVERTURNING.  STRONG ASCENT ATTENDANT TO A
MIDLEVEL SHORTWAVE TROUGH ROTATING NNEWD THROUGH MIDDLE/ERN
TN...CENTRAL KY INTO IND/WRN OH WILL SUPPORT ISOLATED SUSTAINED
UPDRAFTS GIVEN THE PRESENCE OF STRONG DEEP LAYER SHEAR.  THE
AFOREMENTIONED DECREASING TREND IN AVAILABLE CONVECTIVE INSTABILITY
SUGGESTS THE OVERALL COVERAGE OF STRONG TO SEVERE STORMS WILL
CONTINUE TO DIMINISH.  THE GREATEST TORNADO POTENTIAL APPEARS TO BE
ACROSS THE CENTRAL KY PORTION OF WW 103 WHERE EFFECTIVE SRH VALUES
OF 200-300 M2/S2 ARE SUPPORTIVE FOR TORNADOES.  FARTHER N...ANY
STRONGER STORMS THAT FORM WILL BE CAPABLE OF PRODUCING PRIMARILY A
THREAT FOR DAMAGING WINDS AND HAIL.

...SWRN-WEST CENTRAL OH AND NERN IND...
THE LEADING BAND OF TSTMS WILL CONTINUE TO ADVANCE ENEWD INTO
SWRN-WEST CENTRAL OH AND NERN IND BETWEEN 04-05Z.  THE AIR MASS
ACROSS THESE IMMEDIATE DOWNSTREAM AREAS IS EVEN MORE STABLE THAN
LOCATIONS FARTHER S.  THIS COMBINED WITH AN OUTFLOW BOUNDARY MOVING
ENEWD IN ADVANCE OF THE ERN/SERN IND TSTMS SUGGESTS THAT A SEVERE
WEATHER THREAT WILL BE QUITE MINIMAL TO THE NE OF WW 103.  THUS...A
NEW WW IS NOT ANTICIPATED INTO PARTS OF WRN OH AND NERN IND.

...MIDDLE/ERN TN...
ASCENT WITHIN THE SRN EXTENT OF THE SHORTWAVE TROUGH TRACKING NNEWD
THROUGH MIDDLE TN AND CENTRAL KY WILL CONTINUE TO SUPPORT TSTM
DEVELOPMENT WITH SWD EXTENT FROM CENTRAL KY INTO ERN TN. ALTHOUGH
FORCING FOR ASCENT MAY NOT BE AS STRONG AS LOCATIONS FARTHER N...
GREATER INSTABILITY /GIVEN HIGHER PW VALUES/ AND EFFECTIVE BULK
SHEAR OF 40-50 KT SUGGEST ORGANIZED STORMS WILL REMAIN POSSIBLE
THROUGH THE LATE EVENING/EARLY OVERNIGHT.  MODELS DO INDICATE AN
EVENTUAL DIMINISHING TREND IN AVAILABLE INSTABILITY SUCH THAT THE
ONGOING STORMS MOVING INTO ERN TN SHOULD DECREASE IN INTENSITY BY
06Z.  FORCING FOR ASCENT WITH THE SHORTWAVE TROUGH WILL MOVE NEWD
AWAY FROM ERN TN AFTER 06Z...THOUGH EXPECTED HEIGHT FALLS AS LARGE
CLOSED LOW SHIFTS EWD INTO THE OH/TN VALLEYS SHOULD MAINTAIN
CONVECTION OVERNIGHT.

..PETERS.. 03/24/2012

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

ATTN...WFO...MRX...JKL...FFC...ILN...LMK...IWX...OHX...IND...

LAT...LON   35028583 36088590 37048605 37918633 39328635 40148639
            40208636 40628560 40678486 40488432 40238403 39798394
            38988402 38288420 37388416 36348418 35258439 34958478
            35028583

Mesoscale Discussions in Kentucky, 2012Mesoscale Discussions in Indiana, 2012Mesoscale Discussions in Tennessee, 2012Every mesoscale discussion in 2012

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.