DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 280049
SWODY1
SPC AC 280046

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0746 PM CDT MON AUG 27 2007

VALID 280100Z - 281200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE UPR MS
VLY AND WRN GRTLKS REGION...

..UPR MS VLY TO MID-MO VLY...
00Z MPX SOUNDING CONTINUED TO EXHIBIT A SUBSTANTIAL CAPPING
INVERSION WITH A 24 DEG C TEMPERATURE AT THE BASE OF THE EML.
MODIFYING THE SOUNDING USING SFC CONDITIONS REPRESENTATIVE OF THE
WARM SECTOR FARTHER TO THE W AND S STILL RENDERS THE BOUNDARY LAYER
CAPPED /70 J/KG CINH/ AND ONSET OF NOCTURNAL COOLING SUGGESTS THAT
INHIBITION WILL NOT BE ERASED. THUS...THREAT FOR SFC-BASED STORM
INITIATION APPEARS TO HAVE DIMINISHED.

FARTHER TO THE N...COMBINATION OF RIGHT ENTRANCE REGION CIRCULATION
INTO A HIGH LEVEL JET OVER NWRN ONTARIO...STEEP LAPSE RATE
ENVIRONMENT ALOFT AND FAVORABLE LLJ ORIENTATION WITH RESPECT TO
OUTFLOW BOUNDARIES HAVE BEEN FAVORABLE FOR NUMEROUS STG-SVR TSTM
CLUSTERS OVER NRN/CNTRL MN. THESE STORMS ARE EXPECTED TO CONTINUE
ENEWD TOWARD THE LAKE SUPERIOR REGION OVERNIGHT. A FEW OF THESE
STORMS WILL CONTINUE TO PRODUCE LARGE HAIL AND STG TO SVR WIND
GUSTS.

MEANWHILE...THE COLD FRONT MOVING VERY SLOWLY SEWD IN WAKE OF THE
ONTARIO DISTURBANCE WAS BEGINNING TO OVERTAKE A PRE-FRONTAL TROUGH
FROM WCNTRL MN SWWD INTO CNTRL NEB. 00Z OAX/LBF SOUNDINGS SAMPLED A
MUCH DRIER PROFILE THAN AT POINTS FARTHER NE. THERE HAVE BEEN
ATTEMPTS AT SFC-BASED INITIATION AT THE FRONT/TROUGH INTERSECTION
OVER NCNTRL NEB AT LATE AFTN...BUT CINH AND MEAGER DEPTH TO THE
FRONTAL CIRCULATION APPARENTLY ARE NOT FAVORABLE FOR UPDRAFT
SUSTENANCE.

HAVE MAINTAINED A LOW PROBABILISTIC RISK FOR SVR HAIL/WIND ALONG AND
TO THE COOL SIDE OF THE FRONT. WATER VAPOR IMAGERY SHOWS A LOW
AMPLITUDE PERTURBATION MOVING NEWD OUT OF THE CNTRL ROCKIES THIS
EVENING. SLY LLJ IN ADVANCE OF THIS FEATURE SHOULD ENHANCE WARM
ADVECTION PROFILES FROM PARTS OF CNTRL/NRN NEB INTO SERN SD LATER
THIS EVENING. THIS WILL LIKELY RESULT IN ELEVATED BANDS OF TSTMS.
EFFECTIVE SHEAR WILL BE SOMEWHAT WEAK...BUT THE STEEP LAPSE RATES
ALOFT MAY YIELD MARGINALLY SVR HAIL AND PERHAPS A SVR WIND THREAT
WITH ISOLD STORMS.

.RACY.. 08/28/2007

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