[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 260551
SWODY1
SPC AC 260550

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1250 AM CDT SAT AUG 26 2006

VALID 261200Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
BASIN/CNTRL ROCKIES...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE SRN PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE MIDWEST AND PARTS OF
THE ERN GREAT LAKES TO DELMARVA...

...SYNOPSIS...
COMPLEX SYNOPTIC FLOW REGIME WILL EVOLVE ACROSS THE CONUS THIS
PERIOD WITH A NUMBER OF DIFFERENT STREAMS COMPOSED OF RELATIVELY
HIGH-AMPLITUDE MID/UPPER LEVEL WAVES. WITHIN THIS FLOW WILL ALSO
EXIST A NUMBER OF SMALLER-SCALE PERTURBATIONS EMANATING FROM
EPISODES OF WIDESPREAD DEEP CONVECTION. PRIMARY LARGE SCALE FEATURES
DRIVING DEEP CONVECTION WILL INCLUDE MID/UPPER LOW DEVELOPING ACROSS
THE ERN GREAT BASIN...A QUASI-STATIONARY FRONT FROM THE SRN HIGH
PLAINS NEWD TO THE MIDWEST/LOWER MI...AND A BACK DOOR FRONT FROM PA
INTO DELMARVA AREA.

...ERN GREAT BASIN TO CNTRL ROCKIES...
A MIDDLE STREAM UPPER LOW WILL CONTINUE TO TRANSLATE EAST FROM THE
GREAT BASIN TO THE ROCKIES TODAY. MODEST HEIGHT FALLS...MID LEVEL
COLD POOL...AND BAND OF 30-40KT DIFFLUENT MID LEVEL FLOW WILL SPREAD
EAST FROM UT TO WY/CO THIS AFTERNOON. TSTMS SHOULD INCREASE AS THE
SYSTEM MOVES ACROSS UT THROUGH THE AFTERNOON. SIMILAR TO
FRIDAY....STEEP LAPSE RATES AND MOISTENING DUE TO STRONG DPVA WILL
SUPPORT MODEST INSTABILITY WITHIN SUFFICIENTLY SHEARED ENVIRONMENT
FOR PERSISTENT/ORGANIZED STORMS. SUPERCELLS APPEAR LIKELY AND WILL
BE CAPABLE OF PRODUCING HAIL AND HIGH WINDS.

...SRN PLAINS TO MIDWEST...
FROM THE HIGH PLAINS TO THE MID WEST...STALLED SYNOPTIC BOUNDARY
WILL BE INTERSPERSED WITH NUMEROUS CONVECTIVE OUTFLOWS FROM CO/NM
ENEWD ACROSS KS/OK...AND NEWD TO IL. MCS NOW MOVING ACROSS MO WILL
LIKELY INDUCE AN MCV IMPULSE THAT MAY TRACK DOWNSTREAM AND ACROSS
THE MS VALLEY TO THE MIDWEST THROUGH THE DAY. LIFT ASSOCIATED WITH
THIS IMPULSE WILL ACT ON INCREASINGLY UNSTABLE AIR MASS FROM IL TO
IND. ON THE LARGE SCALE...SHEAR REMAINS WEAK ACROSS THESE AREAS.
HOWEVER...FORCING WITH THE MCV AND MAGNITUDE OF INSTABILITY SHOULD
PROVOKE A FEW SEVERE STORMS WITH HAIL AND HIGH WINDS.

IN THE WAKE OF THIS SYSTEM...CLEARING CONVECTIVE DEBRIS ACROSS WRN
MO/KS AND OK...WILL AGAIN RESULT IN STRONG INSTABILITY ACROSS THESE
AREAS. FRONTAL BOUNDARY AND OUTFLOWS WILL PROVIDE A FOCUS FOR
AFTERNOON AND EVENING TSTMS. BELT OF 30-40KT MID LEVEL FLOW WILL
PROVIDE ADEQUATE EFFECTIVE SHEAR ACROSS THE REGION FOR A FEW
SUPERCELLS AND ORGANIZED STORM CLUSTERS WITH DAMAGING WINDS AND
HAIL. ACTIVITY MAY MERGE AND GROW UPSCALE INTO A SLOW MOVING MCS OR
TWO THROUGH SUNDAY MORNING.

...LOWER MI...
IN THE NRN STREAM...TROUGH CROSSING SCNTRL CANADA WILL BRUSH PARTS
OF THE UPPER MS VALLEY AND NRN GREAT LAKES. WHILE STRONGER HEIGHT
FALLS WITH THIS SYSTEM WILL REMAIN PRIMARILY NORTH OF THE BORDER...A
BAND OF SLIGHTLY STRONGER MID LEVEL WLY FLOW WILL DEVELOP EWD ACROSS
LOWER MI...COINCIDENT WITH DIURNAL HEATING AND FRONTAL PASSAGE OVER
THIS AREA. A FEW SEVERE STORMS WITH HAIL AND WIND APPEAR POSSIBLE
ACROSS THIS AREA DURING THE AFTERNOON/EARLY EVENING.

...LAKE ERIE TO DELMARVA...
NW-SE ORIENTED FRONTAL BAND WILL CONTINUE TO SEPARATE CONTINENTAL
POLAR AIR MASS OVER NEW ENGLAND FROM RETURNING TROPICAL MARITIME AIR
ACROSS THE OH VALLEY. LOW AMPLITUDE PERTURBATIONS IN NW FLOW ALOFT
WILL ENHANCE ASCENT ALONG THE LOW LEVEL BOUNDARY AND LEAD TO
SCATTERED TSTM DEVELOPMENT DURING THE DAY. PART OF THE BOUNDARY MAY
SETTLE FARTHER SWWD INTO INCREASINGLY UNSTABLE AIR ACROSS SRN PA/WV
PNHDL AND DELMARVA AREAS THROUGH THE EVENING. DIRECTIONAL SHEAR
ALONG THE BOUNDARY...AS WELL AS DEEP LAYER VERTICAL SPEED
SHEAR...WILL ENHANCE STORM UPDRAFTS WITH A FEW HAIL/WIND EVENTS
POSSIBLE.

..CARBIN.. 08/26/2006