[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 091230
SWODY1
SPC AC 091227

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0727 AM CDT FRI JUN 09 2006

VALID 091300Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL HIGH PLAINS
INTO THE NRN/MID MS RIVER VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE NRN INTERMOUNTAIN
REGION...

...CENTRAL HIGH PLAINS ACROSS IA...
SURFACE LOW OVER SD EARLY THIS MORNING IS FORECAST TO SLOWLY DEVELOP
ESEWD THROUGH THE DAY ALONG QUASI-STATIONARY FRONT NOW EXTENDING
FROM THE LOW CENTER INTO THE LOWER MO RIVER VALLEY.  AS THIS LOW
MOVES ESEWD...SURFACE COLD FRONT WILL PUSH SSWWD INTO ERN WY AND THE
NEB PANHANDLE. CONVERGENCE WILL REMAIN GREATEST NEAR THE LOW CENTER
WHERE MODELS MAINTAIN 30-35 KT SSWLY LLJ THROUGH THE DAY. 
HOWEVER...GIVEN THE LIMITED BOUNDARY LAYER MOISTURE ACROSS THE WARM
SECTOR...CAPPING WILL INHIBIT DEEP MOIST CONVECTION FOR MOST OF THE
DAY.  CONVERGENCE AND ROBUST HEATING MAY SUPPORT ISOLATED
THUNDERSTORM DEVELOPMENT NEAR THE SURFACE FRONT/LOW CENTER FROM NERN
NEB INTO WRN IA LATE TODAY...WHERE DEEP LAYER SHEAR WILL BE MORE
THAN ADEQUATE FOR SUPERCELLS.  EFFECTIVE SHEAR IS FORECAST TO BE
NEAR 50 KT ACROSS THIS REGION WITH MLCAPE AROUND 1000 J/KG.  STORMS
WILL LIKELY BE HIGH-BASED WITH 30 DEGREE T-TD SPREADS MITIGATING
TORNADO THREAT...THOUGH DISCRETE STORMS WILL BE CAPABLE OF LARGE
HAIL ALONG WITH DAMAGING WINDS.  STORMS WILL INCREASE IN COVERAGE
AND BUILD INTO A MCS THROUGH THE EVENING WITHIN EXIT REGION OF LLJ
ALONG AND NORTH OF SURFACE FRONT.  THIS ACTIVITY SHOULD BECOME
INCREASINGLY ELEVATED AS BOUNDARY LAYER COOLS/BECOMES CAPPED WITH
PRIMARY THREAT OF LARGE HAIL.  HOWEVER...ORIENTATION OF SURFACE
BOUNDARY RELATIVE TO WNWLY FLOW ALOFT AND STRENGTH OF DEEP LAYER
SHEAR MAY MAINTAIN A DAMAGING WIND THREAT WELL AFTER DARK SEWD
ACROSS IA AND POSSIBLY NERN MO/NWRN IL.

FARTHER WEST...UPSLOPE FLOW AND SURFACE DEW POINTS AROUND 50F SHOULD
PREVAIL INTO ERN WY/NEB PANHANDLE AND SWRN SD LATER TODAY.  IN
ADDITION...MID LEVEL SHORTWAVE TROUGH APPARENT ON WV IMAGERY THIS
MORNING OVER UT SHOULD OVERSPREAD THE CENTRAL HIGH PLAINS NEAR PEAK
HEATING.  INCREASING ASCENT AND MID LEVEL MOISTURE SHOULD SUPPORT
AFTERNOON THUNDERSTORMS OVER THE HIGHER TERRAIN OF CENTRAL WY/NRN CO
AHEAD OF THIS FEATURE. EFFECTIVE SHEAR FROM 30-40 KT SHOULD BE
SUPPORTIVE OF ORGANIZED MULTICELLS AND SUPERCELLS WHICH MAY PRODUCE
LARGE HAIL AND DAMAGING WINDS AS STRONGER CELLS OVERSPREAD THE HIGH
PLAINS LATER TODAY AND THIS EVENING.  OTHER ISOLATED...HIGH-BASED
DEVELOPMENT MAY OCCUR DUE TO STRONG MIXING/HEATING ALONG SURFACE
TROUGH AXIS FROM WRN KS INTO CENTRAL NEB.

...NRN INTERMOUNTAIN REGION...
STEEP LAPSE RATES AND INCREASING SHEAR ALONG PERIPHERY OF STRONG
UPPER LOW OVER THE NORTHWEST WILL SUSTAIN A SEVERE THREAT ACROSS
THIS AREA TODAY.  APPEARS STORMS WILL STRENGTHEN BY THE MID
AFTERNOON OVER A LARGE PART OF THE NRN INTERMOUNTAIN REGION WITHIN
FAVORABLE DEEP ASCENT. FORECAST SOUNDINGS INDICATE EFFECTIVE SHEAR
FROM 30-40 KT WHICH WILL SUPPORT STORM-SCALE ORGANIZATION...
INCLUDING A FEW SUPERCELLS...INCREASING THE THREAT OF LARGE HAIL AND
DAMAGING WINDS INTO THE EARLY TO MID EVENING.

...PA ACROSS THE MID ATLANTIC...
COLD MID LEVEL THERMAL TROUGH ATOP 50-60F SURFACE DEW POINTS SHOULD
SUPPORT AN AXIS OF MARGINAL INSTABILITY AHEAD OF WEAK SURFACE COLD
FRONT APPROACHING THE REGION TODAY.  STRONGER CELLS WILL BE CAPABLE
OF HAIL/WIND NEAR SEVERE LEVELS BY THE EARLY AFTERNOON WITH ACTIVITY
WEAKENING QUICKLY AFTER DARK.

..EVANS/GRAMS.. 06/09/2006