DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 270054
SWODY1
SPC AC 270052

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 PM CDT MON AUG 26 2013

VALID 270100Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS THROUGH THIS EVENING AND
TONIGHT FROM PORTIONS OF THE DAKOTAS ESEWD INTO PARTS OF WI...

...ND/NRN SD...UPPER MS VALLEY AND UPPER GREAT LAKES...
SLIGHT RISK/SEVERE PROBABILITIES ARE BEING MAINTAINED AS FORECAST
ACROSS THIS REGION. RESIDUAL MODERATE-STRONG INSTABILITY AND
EFFECTIVE BULK SHEAR UP TO 50 KT ORIENTED PARALLEL TO A SURFACE
FRONT EXTENDING EWD FROM NORTH CENTRAL SD THROUGH NORTH CENTRAL MN
TO NRN AND ERN WI SUPPORTS STORM ORGANIZATION. THESE FACTORS
COMBINED WITH AN INCREASE IN LOW LEVEL WAA PER A STRENGTHENING SWLY
LLJ EXTENDING INTO SRN/CENTRAL MN AND VEERING TO WLY OVERNIGHT
SUGGESTS A LIKELIHOOD FOR UPSCALE GROWTH FOR ONE OR MORE CLUSTERS
INTO MCS. HAIL AND DAMAGING WINDS WILL REMAIN A THREAT THIS
EVENING...WHILE A THREAT FOR DAMAGING WINDS COULD BECOME THE PRIMARY
THREAT INTO THE LATE EVENING/EARLY OVERNIGHT PERIOD WITH ANY
POTENTIAL BOWING SEGMENTS.

ASCENT ATTENDANT WITH A WEAK MIDLEVEL IMPULSE...CURRENTLY MOVING
ENEWD THROUGH FAR SERN SASKATCHEWAN AND ADJACENT SWRN MANITOBA...
APPEARS TO BE SUPPORTING A FEW STRONG TO SEVERE STORMS IN NWRN ND
NEAR THE NWRN EXTENSION OF A SURFACE BOUNDARY. THESE STORMS ARE
LOCATED IN A REGION WITH MODERATE INSTABILITY AND EFFECTIVE BULK OF
35-50 KT AND WILL MAINTAIN A THREAT FOR STRONG DAMAGING WINDS AND
HAIL. THIS THREAT MAY DIMINISH LATER THIS EVENING AS THE MIDLEVEL
IMPULSE MOVES FARTHER AWAY FROM THE SURFACE BOUNDARY.

...SRN TIER OF NY/PA...
A PROGRESSIVE SHORTWAVE TROUGH...CURRENTLY MOVING SEWD ACROSS THE
LOWER GREAT LAKES PER SATELLITE IMAGERY...IS EXPECTED TO REACH THE
NRN MID ATLANTIC COAST AND SRN NEW ENGLAND BY 12Z TUESDAY.
ASCENT/SOME MIDLEVEL COOLING WITH THIS FEATURE...AND ADDITIONAL
LOWER TROPOSPHERIC MOISTENING AND WAA FROM NW-SE ACROSS THIS REGION
PER A STRENGTHENING W/NWLY LLJ WILL RESULT IN WEAK DESTABILIZATION
THROUGH TONIGHT. THUS...WILL MAINTAIN POTENTIAL FOR TSTMS AND
LOCALLY STRONG WIND GUSTS.

...SWRN AZ...
ONGOING TSTMS LOCATED OVER SOUTH CENTRAL AZ WILL CONTINUE TO TRACK
WNWWD INTO SWRN AZ WHERE THE ENVIRONMENT IS MODERATELY
UNSTABLE...WITH EFFECTIVE BULK SHEAR OF 30-35 KT SUGGESTING SOME
ORGANIZATION WILL BE POSSIBLE. A MOIST AIR MASS WITH PW VALUES
RANGING FROM 1.5 TO NEAR 2 INCH AND DCAPE OF 800-1000 J/KG SUGGEST
LOCALLY STRONG WIND GUSTS WILL BE POSSIBLE THROUGH THE EVENING.
GIVEN THESE FACTORS...THIS OUTLOOK HAS INTRODUCED A LOW /5 PERCENT/
SEVERE WIND PROBABILITY.

..PETERS.. 08/27/2013

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