[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 221730
SWODY2
SPC AC 221729

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1229 PM CDT TUE AUG 22 2006

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS
VALLEY TO LAKE MI...

...SYNOPSIS...
A SERIES OF SHORT WAVE TROUGHS WILL TRANSLATE THROUGH MEAN UPPER
RIDGE ACROSS THE NRN HIGH PLAINS AND NRN PLAINS THIS PERIOD AND
DRIVE EPISODES OF STRONG TO SEVERE TSTM DEVELOPMENT. THE LEADING
FEATURE TO RESULT IN MCS DEVELOPMENT ACROSS ERN DAKOTAS/MN THROUGH
THE DAY 1 PERIOD WAS CURRENTLY SPREADING ACROSS MT. THIS IMPULSE
WILL CREST THE UPPER RIDGE ACROSS THE NRN PLAINS LATE THIS EVENING
BEFORE SLIDING SEWD ACROSS THE UPPER MS VALLEY THROUGH EARLY
WEDNESDAY. A STRONGER TROUGH IS FORECAST TO MOVE INLAND ACROSS THE
PACIFIC NORTHWEST DURING DAY 2. THIS TROUGH WAS CURRENTLY MOVING
TOWARD THE COAST OF NRN CA AND IS EXPECTED TO PRODUCE RELATIVELY
STRONG HEIGHT FALLS ACROSS MT/WY AREA BY LATE IN THE DAY 2
PERIOD...EARLY THURSDAY.

RIDGING...SURFACE AND ALOFT...IS EXPECTED TO KEEP MOSTLY TRANQUIL
CONDITIONS ACROSS MUCH OF THE CENTER OF THE CONUS WHILE DEEP
TROPICAL MOISTURE REMAINS SITUATED ACROSS THE SOUTHERN STATES FROM
AZ TO FL.

...UPPER MS VALLEY TO LAKE MI...
STRONG MCS EXPECTED TO BE ONGOING ACROSS MN/WRN WI WEDNESDAY MORNING
BASED ON LATEST SHORT-RANGE DETERMINISTIC AND ENSEMBLE GUIDANCE.
THIS SYSTEM WILL BE SUPPORTED BY STRONG LOW LEVEL WARM AIR AND
MOISTURE ADVECTION ON THE NOSE OF SWLY LOW LEVEL JET. LEADING EDGE
OF THIS DEEP CONVECTION WILL TRANSLATE INTO INCREASINGLY STABLE AIR
MASS ACROSS NRN WI AND THE U.P. OF MI. HOWEVER...FLANKING PORTION OF
THE MCS AND RESULTANT OUTFLOW WILL SETTLE INTO INCREASINGLY UNSTABLE
AIR MASS ACROSS SRN MN AND SRN WI DURING THE AFTERNOON AND ACT TO
REINFORCE THE QUASISTATIONARY WARM FRONT ACROSS THESE AREAS. MODELS
INDICATE THAT LIFT AND DESTABILIZATION ALONG THE OUTFLOW
BOUNDARY/WARM FRONT WILL BE SUFFICIENT FOR ADDITIONAL CONVECTIVE
DEVELOPMENT DURING THE DAY. EXPECT SEVERE STORM POTENTIAL TO
INCREASE AS THIS ACTIVITY TAPS STRENGTHENING INSTABILITY. PRESENCE
OF STRONG VERTICAL SPEED AND DIRECTIONAL SHEAR ACROSS THE REGION
WILL FURTHER SUPPORT ORGANIZED/PERSISTENT UPDRAFTS CAPABLE OF
PRODUCING VERY LARGE HAIL AND HIGH WINDS.

INITIAL ACTIVITY MAY BE ROOTED SLIGHTLY ABOVE CAPPED BOUNDARY LAYER
WITH STRONG WARM SECTOR HEATING POSSIBLY PROMOTING MORE
SURFACE-BASED DEVELOPMENT NEAR THE WARM FRONT BY AFTERNOON. IF THIS
CAN OCCUR...MODEST LOW LEVEL DIRECTIONAL SHEAR/HELICITY COUPLED WITH
MAGNITUDE OF FORECAST INSTABILITY MAY ENHANCE TORNADO POTENTIAL FOR
ANY DISCRETE CELLS TRACKING SEWD NEAR THE FRONT. CURRENT INDICATIONS
SUGGEST THAT THIS POTENTIAL MAY REMAIN ISOLATED/BRIEF GIVEN STRENGTH
OF CAP AND LACK OF STRONGER FORCING.

...NRN HIGH PLAINS LATE...
STRONG FORCING FOR ASCENT IS EXPECTED TO EMERGE ACROSS MT/WRN ND
LATER IN THE PERIOD AS UPPER TROUGH AND HEIGHT FALLS DEVELOP ACROSS
THE REGION. LINEAR CONVECTIVE DEVELOPMENT IN LOW-CAPE HIGH-SHEAR
ENVIRONMENT ALONG ADVANCING COLD FRONT OVER WRN/CNTRL MT COULD
SUPPORT SOME LATE NIGHT TSTMS WITH ISOLATED DAMAGING WINDS. FARTHER
EAST...FROM ERN MT INTO ND...LOW LEVEL ELY FLOW NORTH OF DEVELOPING
LEE-SIDE LOW MIGHT SUSTAIN MOIST UPSLOPE FLOW WITH POTENTIAL FOR
MODEST INSTABILITY AND STRONG FORCING PROVIDING FOR A FEW SEVERE
STORMS WITH HAIL/WIND INTO EARLY THURSDAY MORNING.

..CARBIN.. 08/22/2006