[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 171249
SWODY1
SPC AC 171248

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0748 AM CDT THU AUG 17 2006

VALID 171300Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM EASTERN MT ACROSS PARTS OF
THE DAKOTAS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF
KS...NEB...IA...AND MO...

...NORTHERN PLAINS...
ZONAL FLOW PATTERN WILL PERSIST ACROSS THE NORTHERN U.S. TODAY...
WITH SERIES OF SHORTWAVE TROUGHS MOVING FROM THE NORTHERN ROCKIES TO
THE GREAT LAKES.  ONE STRONG TROUGH IS CURRENTLY OVER PARTS OF
ORE/ID...AND IS FORECAST TO TRACK EASTWARD ACROSS MT THIS AFTERNOON
AND EVENING.  THE AIRMASS OVER THE NORTHERN PLAINS /EASTERN MT INTO
ND/ WILL REMAIN QUITE MOIST TODAY JUST NORTH OF SURFACE BAROCLINIC
ZONE.  POCKETS OF AFTERNOON HEATING IN THIS AREA...COUPLED WITH
EASTERLY/UPSLOPE FLOW WILL HELP TO INITIATE AFTERNOON THUNDERSTORMS
OVER THE BLACK HILLS AND BIGHORN MTNS OF MT/WY/SD.  VERTICAL SHEAR
PROFILES IN THIS AREA WILL PROMOTE SUPERCELL STRUCTURES CAPABLE OF
HAIL AND DAMAGING WINDS.  LIMITED FORCING FOR UPWARD VERTICAL MOTION
WILL LIKELY LIMIT AREAL COVERAGE OF THUNDERSTORMS UNTIL AFTER DARK.

DURING THE EVENING...UPPER TROUGH WILL APPROACH FROM THE WEST. 
STRONGER FORCING WILL OVERSPREAD WESTERN EDGE OF DEEPER LOW LEVEL
MOISTURE OVER SOUTHEAST MT AND NORTHEAST WY.  SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS AREA AND PROPAGATE
EASTWARD INTO PARTS OF THE DAKOTAS OVERNIGHT.  CAPE/SHEAR PARAMETERS
AND STRENGTH OF UPPER FORCING SUGGEST THAT SUPERCELLS/BOWS WILL BE
POSSIBLE THROUGHOUT THE NIGHT WITH DAMAGING WINDS AND HAIL IN
STRONGER STORMS.

...KS/NEB/IA/MO...
WEAK SURFACE BOUNDARY CURRENTLY EXTENDS FROM SOUTH CENTRAL NEB INTO
MO.  THIS BOUNDARY IS FORECAST TO LIFT NORTHWARD TODAY...WITH
MOIST/UNSTABLE AIRMASS SOUTH OF FRONT SPREADING ACROSS MUCH OF
NEB/IA.  STRONG DAYTIME HEATING WILL LEAD TO STEEP LOW LEVEL LAPSE
RATES AND MODERATE INSTABILITY /MLCAPE VALUES OVER 2500 J/KG/. 
MORNING WATER VAPOR IMAGERY SHOWS PLUME OF MID LEVEL MOISTURE FROM
THE TX PANHANDLE INTO SOUTHEAST NEB.  COMBINATION OF CONVERGENCE
NEAR RETREATING BOUNDARY...FAVORABLE MID LEVEL MOISTURE...AND FULL
SUNSHINE WILL HELP TO INITIATE THUNDERSTORMS FROM EASTERN KS/NEB
INTO WESTERN IA/MO THIS AFTERNOON.  THESE STORMS MAY MOVE AS FAR
EAST AS THE MISSISSIPPI RIVER THIS EVENING BEFORE WEAKENING. 
LOCALLY GUSTY/DAMAGING WINDS ARE EXPECTED IN STRONGER STORMS.

..HART/LEVIT.. 08/17/2006