[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 240601
SWODY1
SPC AC 240600

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT THU AUG 24 2006

VALID 241200Z - 251200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PORTIONS OF ERN SD THROUGH
CNTRL AND SRN MN AND EXTREME NRN IA...

...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE NRN AND
CNTRL PLAINS THROUGH THE UPPER MS VALLEY AREA...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE OH VALLEY
THROUGH MID ATLANTIC AND NERN U.S....

...SYNOPSIS...

STRONG SHORTWAVE TROUGH OVER THE NRN ROCKY MOUNTAIN REGION WILL MOVE
EWD INTO THE NRN PLAINS AND UPPER MS VALLEY THIS PERIOD...RESULTING
IN LEE CYCLOGENESIS AND DEAMPLIFICATION OF SHORTWAVE RIDGE. A MORE
SUBTLE LEAD VORT MAX CURRENTLY OVER SRN MT WILL MOVE EWD IN ADVANCE
OF THE MAIN UPPER TROUGH. A COLD FRONT WILL ACCOMPANY THE SHORTWAVE
TROUGH INTO THE NRN PLAINS. BY EARLY THURSDAY THE FRONT WILL EXTEND
FROM ERN MT SWWD THROUGH ERN WY. THIS BOUNDARY ALONG WITH DEVELOPING
LEE CYCLONE WILL ADVANCE EWD THROUGH THE DAKOTAS DURING THE DAY. A 
QUASISTATIONARY FRONT WILL EXTEND FROM THE LOW OVER SD EWD THROUGH
SRN MN AND SRN WI.


...NRN PLAINS THROUGH UPPER MS VALLEY AREA...

RESERVOIR OF UNTAPPED INSTABILITY WILL PERSIST OVER PORTIONS OF SD
INTO SRN MN GENERALLY NEAR AND S OF E-W FRONT. BOUNDARY LAYER IN
WARM SECTOR WILL MOST LIKELY REMAIN CAPPED BY A STRONG EML MUCH OF
THE DAY. STORMS MAY BE ONGOING EARLY THURSDAY N OF FRONT MOSTLY
ACROSS ND AS FORCING FOR ASCENT ACCOMPANYING LEAD SHORTWAVE TROUGH
INCREASES. DOWNSTREAM FROM THIS ACTIVITY AND ESPECIALLY S OF E-W
FRONT FROM CNTRL AND ERN SD INTO SRN MN...THE ATMOSPHERE SHOULD
BECOME VERY UNSTABLE AS SURFACE HEATING COMMENCES. STORMS MAY
INITIALLY INTENSIFY ALONG EWD ADVANCING COLD FRONT. STRONG LINEAR
FORCING ENHANCED BY DEEP LAYER ASCENT ACCOMPANYING EWD ADVANCING
SHORTWAVE TROUGH MAY RESULT IN ACTIVITY EVOLVING INTO A LINEAR MCS.
HOWEVER...SOME SUPERCELL STRUCTURES WILL BE POSSIBLE ESPECIALLY
ALONG SRN END OF THE LINE. DAMAGING WIND AND LARGE HAIL WILL BE THE
MAIN THREATS...BUT AN ISOLATED TORNADO OR TWO WILL ALSO BE POSSIBLE
WITH ANY SUPERCELL MODES WITHIN THE LINE.

FARTHER EAST...ASCENT ASSOCIATED WITH LEAD SHORTWAVE TROUGH AND A
BRANCH OF THE LOW LEVEL JET E OF SURFACE LOW WILL MAINTAIN FORCING
FOR ASCENT ALONG AND N OF THE E-W STATIONARY FRONT. POTENTIAL WILL
EXIST FOR STORMS TO DEVELOP NEAR AND JUST N OF THE BOUNDARY AS THE
CAP WEAKENS DURING THE AFTERNOON. ESELY LOW LEVEL FLOW NEAR FRONT
VEERING TO WSWLY AND INCREASING TO 40+ KT AT 6 KM WILL CONTRIBUTE TO
FAVORABLE LOW LEVEL AND DEEP LAYER SHEAR PROFILES FOR SUPERCELLS
WITH LOW LEVEL MESOCYCLONES. VERY LARGE HAIL AND A FEW TORNADOES
WILL BE POSSIBLE WITH ANY DISCRETE SUPERCELLS THAT DEVELOP NEAR THIS
BOUNDARY. OVERNIGHT...STORMS MAY EVOLVE INTO ONE OR MORE MCSS AS THE
LOW LEVEL JET INCREASES WITH A CONTINUING THREAT FOR MAINLY DAMAGING
WIND AND LARGE HAIL FROM THE UPPER MS VALLEY INTO PARTS OF THE GREAT
LAKES.

...OH VALLEY THROUGH MID ATLANTIC AND NERN STATES...

STORMS MAY STILL BE IN PROGRESS IN WARM ADVECTION REGIME FROM PARTS
OF SRN LOWER MI INTO NRN OH EARLY THURSDAY. POTENTIAL WILL EXIST FOR
SOME OF THIS ACTIVITY TO BECOME SURFACE BASED AS THE DOWNSTREAM
ATMOSPHERE DESTABILIZES. PRIMARY THREAT WILL BE DAMAGING WIND AS
ACTIVITY ADVANCES ESEWD. OTHER STORMS MAY DEVELOP DOWNSTREAM OVER
PARTS OF THE MID ATLANTIC AS THE ATMOSPHERE DESTABILIZES AND AS VORT
MAX ROTATES SEWD THROUGH BASE OF UPPER TROUGH. BOUNDARY LAYER FLOW
WILL BE RATHER WEAK...BUT DEEP LAYER VERTICAL SHEAR WILL BE
SUFFICIENT FOR UPDRAFT ROTATION. POOR MID LEVEL LAPSE RATES AND
MODEST INSTABILITY WILL LIMIT OVERALL HAIL POTENTIAL. HOWEVER...THE
STRONGER STORMS MAY BECOME CAPABLE OF PRODUCING ISOLATED DAMAGING
WIND GUSTS.

..DIAL/GUYER.. 08/24/2006