MESOSCALE DISCUSSION 1169
NWS STORM PREDICTION CENTER NORMAN OK
1029 AM CDT WED JUN 17 2009
AREAS AFFECTED...MIDDLE/ERN TN AND CENTRAL/ERN KY
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 171529Z - 171630Z
TSTMS EXPECTED TO DEVELOP AND SLOWLY INCREASE IN COVERAGE/INTENSITY
ACROSS CENTRAL/ERN KY AND MIDDLE/ERN TN THIS MORNING INTO THE
AFTERNOON. HAIL AND STRONG WIND GUSTS WILL BE THE PRIMARY THREATS
WITH THE STRONGER STORMS...AND A WW IS POSSIBLE FOR THIS REGION.
15Z SURFACE ANALYSIS SHOWED AN AREA OF LOW PRESSURE OVER LOWER MI
WITH A WARM FRONT EXTENDING SEWD INTO ERN OH AND THEN SSWWD THROUGH
ERN KY/TN TO NWRN GA. A COUPLE OF WEAKER SURFACE BOUNDARIES...ALSO
DISCERNIBLE WITH VISIBLE SATELLITE IMAGERY...EXTENDED FROM NRN KY
WNWWD THROUGH SRN IL/CENTRAL MO...AND A SECOND BOUNDARY EXTENDED
GENERALLY WNWWD THEN SWWD ACROSS TN INTO NRN AR. THIS LATTER
BOUNDARY IS ATTENDANT TO A MID LEVEL IMPULSE TRACKING SEWD ACROSS
CENTRAL TN.
SURFACE TEMPERATURES RISING INTO THE 80S WITHIN A VERY MOIST AIR
MASS /SURFACE DEWPOINTS IN THE LOWER 70S/ ALONG AND WEST OF THE WARM
FRONT IS CONTRIBUTING TO MODERATE INSTABILITY ALREADY ACROSS THE
DISCUSSION AREA. TSTMS SHOULD DEVELOP AS INHIBITION CONTINUES TO
WEAKEN. FORCING FOR ASCENT WITH THE MID LEVEL IMPULSE TRACKING SEWD
ACROSS TN AND SRN EXTENT OF STRONGER FORCING ATTENDANT TO SRN GREAT
LAKES SHORT WAVE TROUGH WILL SUPPORT TSTM DEVELOPMENT ALONG THE
SURFACE BOUNDARIES. MODEST MID LEVEL LAPSE RATES /6.5-7 C/KM/ MAY
TEND TO INHIBIT MORE VIGOROUS UPDRAFTS...BUT EFFECTIVE BULK SHEAR
/35-40 KT/ WITHIN NWLY FLOW REGIME WILL SUPPORT STORM ORGANIZATION.
HAIL AND STRONG WIND GUSTS SHOULD BE THE PRIMARY THREAT WITH THE
STRONGEST STORMS.
..PETERS.. 06/17/2009
