SPC AC 210551
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1251 AM CDT MON AUG 21 2006
VALID 221200Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NRN PLAINS...
UPPER RIDGE SHOULD FLATTEN ACROSS THE NRN HIGH PLAINS DURING THE
LATTER HALF OF THE PERIOD AS PACIFIC NW TROUGH MOVES INLAND AND
STRONGER MID-HIGH LEVEL FLOW SPREADS ACROSS ID INTO MT/WY. THIS
FEATURE SHOULD INDUCE SFC CYCLOGENESIS ALONG THE LEE OF THE SRN
MT/NRN WY MOUNTAINS WHICH WILL ALLOW MODIFIED BOUNDARY LAYER
MOISTURE TO RETURN TO A REGION THAT SHOULD SEE STRONG LOW LEVEL
HEATING. ALTHOUGH TIMING OF UPPER TROUGH WILL BE DELAYED FROM
STRONGEST HEATING...IT APPEARS HIGH BASED THUNDERSTORMS WILL DEVELOP
FROM CNTRL MT...ARCING SEWD INTO THE NEB PANHANDLE AS SFC PARCELS
REACH THEIR CONVECTIVE TEMPERATURE. DURING THE OVERNIGHT
HOURS...LLJ SHOULD STRENGTHEN SIGNIFICANTLY FROM THE NEB PANHANDLE
INTO ND...THUS LOW LEVEL WARM ADVECTION SHOULD CONTRIBUTE TO THE
LONGEVITY AND INTENSITY OF THUNDERSTORMS THAT SPREAD OFF THE HIGHER
TERRAIN. FORECAST SOUNDINGS STRONGLY FAVOR SUPERCELL DEVELOPMENT
WITH INITIAL ACTIVITY EXPECTED TO BE HIGH BASED. THUNDERSTORMS THAT
INITIATE ACROSS THE HIGH PLAINS OF MT/WY SHOULD EVOLVE WITHIN
INVERTED-V TYPE PROFILES. THIS WOULD CERTAINLY FAVOR DAMAGING
DOWNBURSTS BEFORE ACTIVITY GRADUALLY BECOMES ELEVATED IN NATURE
AFTER DARK WITH DECOUPLING OF BOUNDARY LAYER. EVEN SO...STRONG
WINDS COULD PERSIST GIVEN THE EXPECTED STEEP LAPSE RATE
ENVIRONMENT...IN ADDITION TO THE POSSIBILITY OF LARGE HAIL.
...NEW ENGLAND TO THE LOWER GREAT LAKES...
MODELS CONTINUE THEIR EARLIER TRENDS WITH NOTABLE HEIGHT FALLS
ACROSS SERN CANADA AND THE NERN PORTIONS OF THE U.S. TUESDAY.
ALTHOUGH VERTICAL SHEAR PROFILES WILL SUPPORT ORGANIZED UPDRAFTS
ALONG ADVANCING COLD FRONT...IT APPEARS BOUNDARY LAYER BUOYANCY WILL
BE SOMEWHAT TEMPERED BY MEAGER LOW LEVEL MOISTURE AND WEAK MID LEVEL
LAPSE RATES. ISOLATED-SCATTERED THUNDERSTORMS SHOULD DEVELOP ALONG
SFC WIND SHIFT BUT THE THREAT OF ORGANIZED SEVERE STORMS WITH
DAMAGING WINDS APPEARS INSUFFICIENT TO WARRANT A SLIGHT RISK AT THIS
TIME.
..DARROW.. 08/21/2006
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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