[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 261954
SWODY1
SPC AC 261952

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT SAT AUG 26 2006

VALID 262000Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE GREAT LAKES
AND OH VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND SRN
PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE INTERMOUNTAIN
WEST...

...GREAT LAKES INTO OH VALLEY...

FORCING FOR UPWARD VERTICAL MOTION IS BEING ENHANCED THIS AFTERNOON
BY: 1) SHORT WAVE TROUGH AND ASSOCIATED SPEED MAX OVER THE U.P. AND
LAKE MI...AND 2) MCV OVER NRN/CNTRL IL.  WHILE CONSIDERABLE CLOUDS
HAVE LIMITED DIABATIC HEATING AND RESULTANT DESTABILIZATION...MOIST
BOUNDARY LAYER CONDITIONS ARE CONTRIBUTING TO MLCAPES OF 500-1000
J/KG FROM LOWER MI INTO IL/IND.  THE STRONGEST STORMS THUS FAR TODAY
HAVE BEEN LOCATED OVER PARTS OF LOWER MI INVOF SURFACE LOW MOVING
INTO THE W-CNTRL PART OF THE STATE.  MESOANALYSIS INDICATES THAT
ATTENDANT WARM FRONT EXTENDS FROM THIS LOW EWD TO N OF RBQ AND THEN
SEWD TO NEAR MTC.  SHEAR PROFILES ALONG THIS BOUNDARY ARE SUPPORTIVE
OF SUPERCELLS OWING TO PRONOUNCED LOW-LEVEL HODOGRAPH CURVATURE AND
AROUND 35 KTS OF EFFECTIVE BULK SHEAR.

FURTHER AIR MASS DESTABILIZATION AND APPROACH OF IMPULSES FROM THE
NW AND SW SHOULD CONTRIBUTE TO INCREASED COVERAGE AND INTENSITY OF
STORMS OVER LOWER MI THIS AFTERNOON INTO EVENING WITH THE MAIN
THREAT BEING SEVERE HAIL AND LOCALLY DAMAGING WINDS.  GREATEST
POTENTIAL FOR A TORNADO OR TWO WILL BE WITH ANY SURFACE-BASED
SUPERCELLS THAT CAN FAVORABLY INTERACT WITH SURFACE WARM FRONT.

ADDITIONAL STRONG TO POTENTIALLY SEVERE STORMS WILL BE POSSIBLE SWWD
ALONG TRAILING COLD FRONT INTO PORTIONS OF NRN IL...AS WELL AS AHEAD
OF MCV INTO IND/OH WHERE STRONGER DESTABILIZATION IS OCCURRING. 
VERTICAL SHEAR REMAINS COMPARATIVELY WEAKER THAN POINTS TO THE
N...WITH THE MAIN THREATS BEING MARGINALLY SEVERE HAIL AND LOCALLY
STRONG WIND GUSTS WITH ORGANIZED MULTICELL CLUSTERS.


...SERN KS/OK INTO THE TX PNHDL/NWRN TX...

VISIBLE SATELLITE AND MESOANALYSIS INDICATE THAT OUTFLOW FROM
NOCTURNAL CONVECTION HAS ESTABLISHED A BOUNDARY WELL S OF PRIMARY
SYNOPTIC FRONT FROM CNTRL AR WWD TO CNTRL OK AND THEN SWWD TO NEAR
ABI.  THE MAIN COLD FRONT EXTENDED FROM NEAR CNU TO NEAR PVW AS OF
18Z.  WHILE 12Z REGIONAL SOUNDINGS INDICATED THAT MID-LEVEL LAPSE
RATES WERE RELATIVELY POOR /AROUND 6.5 C/KM/...DAYTIME HEATING AND
DEWPOINTS OF 65-70 F ARE CONTRIBUTING TO DESTABILIZATION OF
PRE-FRONTAL AIR MASS WITH MLCAPES LIKELY REACHING 2000-3000 J/KG
LATER THIS AFTERNOON.

WHILE LARGE-SCALE FORCING FOR ASCENT IS EXPECTED TO REMAIN RATHER
WEAK...CONVERGENCE ALONG THE LOW-LEVEL BOUNDARIES SHOULD SUPPORT AN
INCREASE IN STORM COVERAGE AND INTENSITY BOTH ALONG THE OUTFLOW
BOUNDARY AND MAIN FRONT.  AREA VWPS AND PROFILERS INDICATE THAT
VERTICAL SHEAR IS MARGINAL FOR STORM ORGANIZATION...WITH MULTICELL
CLUSTERS THE MOST LIKELY CONVECTIVE MODE.  THE STRONGEST STORMS WILL
BE CAPABLE OF SEVERE HAIL AND DAMAGING WIND GUSTS.

...INTERMOUNTAIN WEST...

AFTERNOON WATER VAPOR IMAGERY INDICATES MID/UPPER LOW MOVING SEWD
INTO NRN UT WITH STRONGEST HEIGHT FALLS SHIFTING ACROSS ERN UT INTO
WRN CO.  TSTMS ARE RAPIDLY INCREASING IN COVERAGE THIS AFTERNOON
WITHIN THIS ZONE OF HEIGHT FALLS WHERE STEEP LAPSE RATES ARE
CONTRIBUTING TO MLCAPES OF 500-1000 J/KG.  GJT VWP INDICATES
RELATIVELY STRONG FLOW ABOVE THE BOUNDARY LAYER /I.E. 35 KT WLY
WINDS AT 2 KM AGL INCREASING TO 60 KTS OUT OF THE SW AT 6 KM AGL/
WITH VERTICAL SHEAR MORE THAN SUFFICIENT FOR SUPERCELLS CAPABLE OF
DAMAGING WINDS AND LARGE HAIL.

FOR ADDITIONAL SHORT TERM GUIDANCE...PLEASE SEE MCD 1891.

..MEAD.. 08/26/2006