SPC AC 180611
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0111 AM CDT TUE SEP 18 2007
VALID 201200Z - 211200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER THE RED RIVER VALLEY INTO
UPPER MS VALLEY...
...SYNOPSIS...
SHORT WAVE TROUGH ORIGINATING OVER BRITISH COLUMBIA/ALBERTA IS
FORECAST TO AMPLIFY AS IT TRANSLATES SEWD INTO SASKATCHEWAN/MANITOBA
AND THE ADJACENT N-CNTRL TIER OF STATES. SURFACE LOW INITIALLY OVER
SERN MT IS EXPECTED TO DEVELOP EWD ALONG THE SD/ND BORDER THURSDAY
BEFORE LIFTING MORE NEWD INTO NRN MN AND EVENTUALLY WRN ONTARIO
THURSDAY NIGHT INTO FRIDAY MORNING. WARM FRONT PRECEEDING THIS LOW
WILL CONCURRENTLY LIFT NWD THROUGH CNTRL/NRN PORTIONS OF MN/WI AND
THE UP OF MI WHILE TRAILING COLD FRONT PUSHES SEWD THROUGH THE
DAKOTAS.
...DAKOTAS INTO MN...
CLUSTERS OF MAINLY ELEVATED TSTMS /SOME CAPABLE OF SEVERE HAIL/ ARE
FORECAST TO BE ONGOING THURSDAY MORNING OVER PORTIONS OF CNTRL
ND...DRIVEN LARGELY BY WAA ALONG NOSE OF 40-50 KT SLY LLJ. THESE
STORMS WILL LIKELY PERSIST THROUGH THE DAY...LIKELY BECOMING
SURFACE-BASED BY AFTERNOON OVER THE RED RIVER VALLEY WHERE
INCREASING BOUNDARY LAYER MOISTURE AND STEEP LAPSE RATES WILL
CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS. 40-50 KT SLY/SWLY LLJ
AND 45-55 KT WSWLY MID-LEVEL FLOW WILL RESULT IN A KINEMATIC
ENVIRONMENT QUITE SUPPORTIVE OF ORGANIZED STORMS...INCLUDING
SUPERCELLS CAPABLE OF DAMAGING WINDS...LARGE HAIL AND PERHAPS
TORNADOES.
CLUSTERS OF SEVERE STORMS SHOULD CONTINUE EWD ACROSS NRN/CNTRL
PORTIONS OF MN THURSDAY NIGHT WITH THE POTENTIAL FOR SWD/SWWD STORM
DEVELOPMENT ALONG TRAILING COLD FRONT INTO NERN SD.
..MEAD.. 09/18/2007
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z
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