[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 162005
SWODY1
SPC AC 162003

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0303 PM CDT WED AUG 16 2006

VALID 162000Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS ERN OR TO WRN MT...

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS CENTRAL/ERN
DAKOTAS...NWRN MN...

...SYNOPSIS...
PROGRESSIVE NRN STREAM PATTERN CONTINUES...WITH HEIGHT FALLS
CONCENTRATED ACROSS NRN ROCKIES ATTM.  STRONG MIDDLE-UPPER LEVEL
TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER CASCADES --
IS FCST TO MAINTAIN POSITIVE TILT WHILE DRIFTING EWD ACROSS
CENTRAL/ERN PORTIONS WA/ORE AND NRN CA.  FARTHER DOWNSTREAM...WEAK
SHORTWAVE TROUGH EMBEDDED IN SW FLOW ALOFT WILL CONTINUE TO MOVE
ENEWD ACROSS ND AND NWRN CORNER OF MN.

AT SFC...LOW EVIDENT OVER EXTREME N-CENTRAL ND/SWRN MB ATTM SHOULD
WEAKEN AS ASSOCIATED TROUGH MOVES PAST...AND AS ACCOMPANYING COLD
FRONT MOVES SEWD OVER ND AND NWRN MN.  TRAILING PORTION OF THIS
FRONT WILL CONTINUE MOVING SWD OVER CENTRAL/ERN MT...BECOMING
QUASISTATIONARY INVOF WY BORDER BY END OF PERIOD AS PRESSURES
CONTINUE TO FALL IN WRN WY/SWRN ID.  SECOND LOW IS ANALYZED OVER MO
RIVER NEAR SD/ND BORDER...WITH WEAK COLD FRONT SWWD INTO SRN BLACK
HILLS AND WARM FRONT ENEWD ACROSS SERN ND AND NRN MN.  BAROCLINIC
ZONES SHOULD MERGE BY LATE TONIGHT AND BECOME NEARLY STATIONARY FROM
N-CENTRAL SD TO NRN MN.

...INTERIOR NWRN CONUS...NRN ROCKIES...
AIR MASS CONTINUES TO DESTABILIZE ATTM BOTH SFC AND ALOFT.  SFC
DIABATIC HEATING AND DPVA IN MIDLEVELS ARE RESULTING IN STEEP
UNSTABLE DEEP-LAYER LAPSE RATES AMIDST FAVORABLE VERTICAL SHEAR
PROFILES...AHEAD OF MID/UPPER LEVEL TROUGH.  COVERAGE AND INTENSITY
OF TSTMS WILL CONTINUE TO GROW FOR A FEW MORE HOURS AS ACTIVITY
INITIALLY OVER ERN ORE AND CENTRAL ID SHIFTS NEWD...WITH ADDITIONAL
DEVELOPMENT POSSIBLE SWRN THROUGH W-CENTRAL MT.  REF SPC WW 723 AND
RELATED MESOSCALE DISCUSSIONS FOR SHORT-TERM DETAILS.  SVR POTENTIAL
SHOULD DIMINISH AFTER DARK FROM COMBINATION OF DIABATIC SFC COOLING
AND INCREASING COVERAGE OF OUTFLOW AIR.

...NRN PLAINS...
TSTMS ARE FCST TO DEVELOP AND BECOME SVR OVER PORTIONS CENTRAL/ERN
DAKOTAS DURING NEXT SEVERAL HOURS...AS CAP WEAKENS AMIDST STRONG
HEATING AND FAVORABLE SFC MOIST AXIS...AHEAD OF SFC FRONT. 
ADDITIONAL DESTABILIZATION ALOFT MAY BE PROVIDED BY WEAK DPVA/ASCENT
ASSOCIATED WITH EJECTING ND SHORTWAVE. DAMAGING GUSTS AND HAIL ARE
POSSIBLE.  REF SPC MESOSCALE DISCUSSION 1822 FOR NOWCAST
INFORMATION.  AFTERNOON ACTIVITY MAY PERSIST THROUGH MUCH OF THIS
EVENING IN NE-SW ORIENTED BAND MOVING SLOWLY EWD ACROSS ERN DAKOTAS
AND PERHAPS NWRN MN.  OVERALL SVR THREAT SHOULD DIMINISH GRADUALLY
LATE THIS EVENING AND INTO OVERNIGHT HOURS.

..EDWARDS.. 08/16/2006