SWODY1
SPC AC 222001
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0301 PM CDT FRI JUN 22 2007
VALID 222000Z - 231200Z
..THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL/NRN HIGH
PLAINS INTO ND...
..THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO TO LOWER OH
RIVER VALLEYS...
..IA TO THE LOWER OH VALLEY...
MID LEVEL IMPULSE/MCV LOCATED OVER IA THIS AFTERNOON WILL TRACK TO
THE SOUTHEAST THIS FORECAST PERIOD REACHING SERN IA/NRN MO BY 12Z
SATURDAY. 35-40 KT OF WNWLY MID LEVEL FLOW ACCOMPANYING THIS SYSTEM
ATOP SWLY LOW LEVEL WINDS WILL CONTINUE TO SUPPORT ORGANIZED
TSTMS...INCLUDING SUPERCELLS INTO THE EVENING. SURFACE ANALYSIS
INDICATED SEVERAL BOUNDARIES /SYNOPTIC AND LEFT OVER OUTFLOW
BOUNDARIES/ EXTENDING FROM THE LOWER OH RIVER VALLEY NWWD TO THE MID
MO RIVER VALLEY. MOIST AIR MASS ALONG/S OF THESE BOUNDARIES
COMBINED WITH SURFACE HEATING WILL CONTINUE TO MAINTAIN MODERATE
INSTABILITY WITH A VERY UNSTABLE AIR MASS INTO ERN NEB.
ASCENT WITH THE IA IMPULSE HAS ALREADY AIDED STRONG TO SEVERE TSTM
DEVELOPMENT OVER PARTS OF CENTRAL IA WHERE MODERATE INSTABILITY AND
EFFECTIVE BULK SHEAR OF 35-45 KT ARE SUPPORTING THIS ACTIVITY. AS
THE IMPULSE TRACKS TOWARD THE SE...TSTMS WILL CONTINUE TO DEVELOP
ESEWD ALONG THE INSTABILITY GRADIENT TOWARD THE MID MS RIVER
VALLEY...AND POTENTIALLY REACH THE LOWER OH VALLEY LATER TONIGHT.
VISIBLE IMAGERY INDICATED CU DEVELOPING WWD INTO WRN IA/ERN NEB
WHERE THE AIR MASS IS VERY UNSTABLE WITH EFFECTIVE BULK SHEAR
SUFFICIENT FOR MULTICELLS. SHORT TERM MODELS SUGGEST TSTMS SHOULD
DEVELOP ACROSS THIS REGION WITH POTENTIAL FOR STRONG TO SEVERE
STORMS PRODUCING PRIMARILY HAIL AND DAMAGING WINDS.
..CENTRAL HIGH PLAINS...
SURFACE HEATING OVER ERN CO INTO SERN WY COMBINED WITH MODEST
BOUNDARY LAYER MOISTURE AND BENEATH STEEP MID LEVEL LAPSE RATES WILL
CONTINUE TO SUPPORT N-S AXIS OF MODERATE INSTABILITY ACROSS THE
CENTRAL HIGH PLAINS. REGIONAL RADARS/LIGHTNING DATA INDICATED TSTMS
HAVE DEVELOPED ALONG AND WEST OF THE FRONT RANGE FROM NRN NM TO SERN
WY. MUCH OF THIS ACTIVITY IS BEING AIDED BY ASCENT WITH WEAK MID
LEVEL IMPULSE LOCATED OVER NRN CO AT THIS TIME...WITH WEAK UPSLOPE
FLOW ALSO SUPPORTING DEVELOPMENT ALONG THE FRONT RANGE. ACTIVITY
ALONG THE FRONT RANGE IS EXPECTED TO SPREAD SLOWLY EWD INTO THE CO
PLAINS...AS ATTENDANT IMPULSE MOVES SEWD TOWARD SERN CO THIS
FORECAST PERIOD. THESE SLOW MOVING STORMS WILL MOVE INTO AXIS OF
MODERATE INSTABILITY AND 20-30 KT DEEP LAYER SHEAR WITHIN WEAK
UPSLOPE REGIME...WITH STRONGER CORES BECOMING CAPABLE OF PRODUCING
LARGE HAIL AND DAMAGING WINDS. MODELS SUGGEST POSSIBLE CONSOLIDATION
OF TSTMS INTO A SLOW MOVING MCS INTO E-CENTRAL/SERN CO...WHICH COULD
SPREAD TOWARDS THE OK/NRN TX PANHANDLE/SWRN KS AREA LATER THIS
EVENING AS A SLY LLJ STRENGTHENS FROM W TX INTO SWRN KS.
..NRN HIGH PLAINS INTO ND...
SURFACE ANALYSIS INDICATED A FRONT TRAILING SWWD FROM SRN MANITOBA
THROUGH WRN ND INTO ERN MT...WITH THIS BOUNDARY ATTENDANT TO A MID
LEVEL IMPULSE TOPPING THE RIDGE IN SRN CANADA. THIS MID LEVEL
FEATURE WILL MOVE INTO ONTARIO TONIGHT WITH FRONT SPREADING EWD INTO
NRN ND/NWRN MN. GIVEN STEEP MID LEVEL LAPSE RATES FROM NRN HIGH
PLAINS INTO WRN ND AND MOIST AIR MASS ALONG/E OF FRONT...THIS REGION
HAS BECOME MODERATELY UNSTABLE. ALTHOUGH STRONGER FLOW ALOFT SHOULD
REMAIN OVER CANADA...SUFFICIENT WLY MID LEVEL ATOP SSWLY LOW LEVEL
WINDS WILL SUPPORT 25-30 KT OF EFFECTIVE BULK SHEAR FOR MULTICELLS
AND A FEW SUPERCELLS GIVEN DEGREE OF INSTABILITY. WEAK MID LEVEL
IMPULSE MOVING EWD ACROSS THE NRN HIGH PLAINS SHOULD AID TSTM
DEVELOPMENT LATER THIS AFTERNOON AND EVENING...WITH ADDITIONAL
POTENTIAL ALONG FRONT INTO NRN ND/NWRN MN.
.PETERS.. 06/22/2007
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