[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 251650
SWODY1
SPC AC 251648

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1148 AM CDT FRI AUG 25 2006

VALID 251630Z - 261200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES REGION
SEWD INTO THE NRN MID ATLANTIC AREA...AND ACROSS THE CENTRAL
PLAINS....

...SYNOPSIS...
SEVERAL MID/UPPER LEVEL LOWS DEFINE THE PATTERN WITH ONE OVER THE
NRN PLATEAU...ANOTHER OVER CENTRAL/SOUTH CENTRAL CANADA AND THE
OTHER OVER CENTRAL/EASTERN QUEBEC.  THIS PLACES THE MAIN STORM TRACK
FROM NRN NEVADA NEWD THRU WY...THEN EWD ACROSS THE UPPER GREAT LAKES
THEN SEWD THRU THE LOWER GREAT LAKES INTO THE NRN MID ATLANTIC
REGION.  THE LATEST SURFACE ANALYSIS EXTENDS A WARM FRONT FROM A LOW
OVER SERN MN EWD/SEWD ACROSS SRN WI INTO SERN LOWER MI...THEN
CONTINUES AS A QUASI STATIONARY FRONT THRU NERN OH THRU NRN NJ.  IN
ADDITION...A WEAK COLD FRONT EXTENDS FROM THE MN LOW SWWD ACROSS
SWRN IA AND NERN KS THEN WWD THRU EXTREME SWRN KS AND SRN CO.

...SRN WI ESEWD ACROSS NERN OH INTO NJ...

MODELS ARE ALL IN FAIR AGREEMENT OF DEVELOPING STRONG CONVECTION
OVER PARTS OF SRN LOWER MI INTO NERN OH/NWRN PA AND AGAIN FROM NERN
PA INTO NJ LATER THIS AFTERNOON AND TONIGHT.  MODELS DO NOT DEVELOP
ANY LOW LEVEL FLOW TOWARDS THE QUASI-STATIONARY BOUNDARY ACROSS THIS
REGION...BUT DOES HAVE A FAVORABLE ENTRANCE REGION OF THE MID/UPPER
LEVEL JET STREAK THAT IS FORECAST FROM SRN LK HURON OVER SWRN AND
SERN NY.  IT ALSO LOOKS LIKE THE MODELS WANT TO TAKE THE CONVECTION
CURRENTLY OVER SRN WI AND TRACK IT EWD/SEWD INTO THIS AREA.  THE 15Z
RUC IS CONSISTENT WITH THIS SCENARIO...DESTABILIZING THE AIR MASS
WITH SBCAPE BETWEEN 1500-2000 J/KG WITH DEEP LAYER SHEAR OF 45-55
KT.  ANALYSIS OF MODEL SOUNDINGS FOR CLE SUGGESTS MID LEVEL LAPSE
RATES NEAR 7C/KM WITH MID LEVEL DRYING PRESENT SUGGESTS THAT STORMS
THAT DO DEVELOP IN WNWLY FLOW ALOFT HAVE THE POTENTIAL FOR DAMAGING
WINDS AND HAIL THAT CAN TRACK/REDEVELOP ESEWD ACROSS PA/SRN NY STATE
INTO NJ TONIGHT.  GIVEN THE VERTICAL PROFILES ARE FAVORABLE FOR
ISOLATED SUPERCELLS /0-3KM HELICITY NEAR 300 M2/S2/...AN ISOLATED
TORNADO IS POSSIBLE NEAR/JUST N OF THE BOUNDARY.

...SRN WI SWWD INTO THE GREAT PLAINS...

AIR MASS IS VERY WARM...MOIST AND MODERATELY UNSTABLE AT THIS TIME
ALONG AND AHEAD OF FRONTAL BOUNDARY.  MLCAPE IS CURRENTLY 1500-2500
J/KG FROM CENTRAL KS ENEWD INTO S CENTRAL IA.  MODELS ENHANCE UVVS
ACROSS MUCH OF THE CENTRAL PLAINS IN THE VICINITY OF THE BOUNDARY S
OF UPPER LEVEL JET STREAK OF 80-100 KT.  MODELS DO DEVELOP NOCTURNAL
LOW LEVEL JET OF 40 KT FROM SWRN OK INTO SERN KS WHICH WILL ENHANCE
LOW LEVEL ASCENT NEAR THE BOUNDARY.  SO...MODELS MAY HAVE A GOOD
HANDLE ON DEVELOPING SCATTERED STRONG /SEVERE THUNDERSTORMS LATE
THIS AFTERNOON AND TONIGHT.  LOOK FOR ACTIVITY TO CONTINUE FROM NRN
IL SWWD INTO NERN MO...BUT FOR MORE DEVELOPMENT IN VICINITY OF OLD
CONVECTIVE BOUNDARIES FROM NWRN IL INTO KS DEVELOPING INTO AN MCS
OVERNIGHT.  POTENTIAL INSTABILITY WITH SBCAPE FORECAST BETWEEN
3000-4000 J/KG IS EXPECTED BY TONIGHT AND STEEP MID LEVEL LAPSE
RATES BETWEEN 7-7.5C/KM INDICATES DAMAGING WINDS AND HAIL BEING THE
MAIN THREATS.

...CENTRAL INTERMOUNTAIN REGION...

NAM/RUC MID LEVEL TEMPERATURES ARE FORECAST TO CHANGE LITTLE LATER
TODAY WITH VALUES BEING AROUND -16C IN ASSOCIATION WITH MID/UPPER
LEVEL LOW MOVING SSEWD FROM CENTRAL ID INTO NERN NV/NWRN UT/S
CENTRAL ID BY THE END OF THE PERIOD.  RUC MODEL IS MORE UNSTABLE
THAN THE NAM AND ANALYSIS OF THE FORECAST SOUNDING DO INDICATE A
MUCH DRIER BOUNDARY LAYER ON THE NAM THAN COMPARED TO THE RUC. 
THUS...EXPECT SOME STORMS TO DEVELOP BY THIS EVENING POSSIBLY
PRODUCING SOME STRONG WINDS ACROSS PARTS OF NRN UT GIVEN THAT
VERTICAL PROFILES INDICATE AN INVERTED-V ASPECT.

..MCCARTHY.. 08/25/2006