[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 051300
SWODY1
SPC AC 051258

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0758 AM CDT SAT AUG 05 2006

VALID 051300Z - 061200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM ERN ND INTO ERN SD AND MUCH
OF NRN / WRN MN...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
SWD / EWD INTO THE MID MO AND UPR MS VLYS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE CNTRL GULF CST
REGION...

...SYNOPSIS...
UPR RIDGE WILL REMAIN ANCHORED OVER THE SRN PLNS THIS PERIOD AS
POTENT SHORTWAVE IMPULSE NOW OVER SRN SASKATCHEWAN SWEEPS E IN
STRONG ZONAL JET JUST N OF THE CANADIAN BORDER.  THE SYSTEM SHOULD 
AMPLIFY INTO A CLOSED LOW NEAR LK WINNIPEG EARLY TONIGHT...AND REACH
 WRN ONTARIO EARLY SUNDAY.  FARTHER S...SATELLITE AND VWP DATA SHOW
TWO WEAKER DISTURBANCES IN THE BELT OF MODERATE FLOW TOPPING THE
PLNS RIDGE.  ONE OF THE THESE IS OVER FSD/SUX ATTM...AND THE OTHER
OVER N CNTRL WY.

AT THE SURFACE...COLD FRONT ATTENDING CANADIAN IMPULSE EXPECTED TO
MOVE STEADILY SE ACROSS THE NRN PLNS TODAY...AND INTO THE UPR MS
VLY/CNTRL PLNS TONIGHT/EARLY SUNDAY.  AHEAD OF THE COLD FRONT...
LATEST SURFACE DATA AND SATELLITE/GPS PWS SHOW MOISTURE RETURN
CONTINUING INVOF DIFFUSE WARM FRONT EXTENDING FROM THE CNTRL DAKOTAS
SSE INTO ERN KS/NE OK. MOISTURE LIKELY WILL CONTINUE TO SPREAD NWD
INTO THE ERN DAKOTAS/WRN MN TODAY.  SURFACE DEWPOINTS COULD REACH
THE MID 60S IN THE RED RVR VLY REGION BY MID AFTERNOON...WITH 
VALUES IN THE UPPER 60S POSSIBLE FARTHER S ACROSS ERN SD/SW MN.  THE
W/E BREADTH OF THE MOISTURE RETURN AXIS WILL...HOWEVER...LIKELY
REMAIN LIMITED AS GRT LKS SURFACE RIDGE EXPECTED TO EDGE ONLY SLOWLY
EWD.

...NRN PLNS/UPR MS VLY...
ELEVATED TSTMS ARE ALREADY IN PROGRESS IN NW/N CNTRL ND...IN WARM
ADVECTION ZONE DOWNSTREAM FROM SASKATCHEWAN TROUGH.  THIS ACTIVITY
SHOULD CONTINUE E ACROSS ND THROUGH THE DAY...WITH SOME SWD
DEVELOPMENT LIKELY OVER TIME AS STORMS/FORCING ENCOUNTER INCREASING
LOW LEVEL MOISTURE RETURN AND OVERCOME CAP.  COUPLED WITH EXPECTED
SURFACE HEATING AND CONTINUED E/SEWD PROGRESS OF COLD FRONT...EXPECT
THAT CELLS WILL EVENTUALLY BECOME SURFACE-BASED AND MARKEDLY
STRENGTHEN...MOST LIKELY OVER THE RED RVR VLY. OTHER VIGOROUS
STORMS SHOULD FORM A BIT LATER IN THE AFTERNOON SWD ALONG MERGING
COLD FRONT/PREFRONTAL TROUGH OVER ERN SD/WRN MN.

AMPLE DEEP SPEED AND DIRECTIONAL SHEAR WILL BE PRESENT FOR SUSTAINED
SUPERCELLS...ESPECIALLY IN ND AND NRN MN...WHERE 500 MB WLY FLOW
WILL INCREASE TO AROUND 50 KTS ON SRN SIDE OF UPR TROUGH.  SOMEWHAT
WEAKER DEEP SHEAR WILL BE COMPENSATED BY GREATER INSTABILITY /SBCAPE
TO 3000 J PER KG/ TO SUPPORT SUSTAINED UPDRAFTS/SUPERCELLS SWD INTO
ERN/SRN SD AND SW MN. BY EARLY EVENING...STRONG STORMS COULD DEVELOP
SWD INTO NRN NEB.

COMBINATION OF MODERATE TO STRONG DEEP SHEAR...STEEP MID LEVEL LAPSE
RATES AND INCREASING MOISTURE LIKELY WILL PROMOTE A FEW UPDRAFTS
WITH VERY LARGE HAIL FROM THE RED RVR VLY S/SW INTO  PARTS OF SD/WRN
MN.  AND...WHILE OVERALL CONDITIONS DO NOT APPEAR IDEAL...A FEW
TORNADOES ALSO APPEAR POSSIBLE...ESPECIALLY DURING EXPECTED PERIOD
OF STORM INTENSIFICATION IN THE RED RVR VLY...AND DURING EARLY
STAGES OF STORM DEVELOPMENT IN ERN SD/SW MN.

FOCUSED AND LINEAR FORCING FOR ASCENT SUGGEST THAT ACTIVITY WILL
FAIRLY QUICKLY ORGANIZE INTO A BROKEN LINE MODE THIS EVENING. 
EMBEDDED SUPERCELLS WILL CONTINUE TO POSE A THREAT FOR HIGH
WIND/HAIL AND ISOLATED TORNADOES...ESPECIALLY BENEATH BELT OF
STRONGER FLOW ALOFT IN NRN MN...AND INVOF MERGING BOUNDARIES SRN
MN/SE SD.  WHILE THE SRN MN/SE SD ACTIVITY MAY REMAIN SEVERE INTO
SUNDAY MORNING...AND FORWARD-PROPAGATE E INTO NRN IA/SW WI... 
NARROW NATURE OF INSTABILITY AXIS SHOULD LIMIT EWD EXTENT OF
HIGH-END /DERECHO/ SEVERE THREAT INTO THE LK SUPERIOR REGION.

...NERN GULF COAST/SOUTHEAST...
STRONGLY HEATED...VERY MOIST/UNSTABLE AIR WILL AGAIN SUPPORT POCKETS
OF DIURNAL PULSE/MULTICELL STORMS IN AREAS WHERE DEEP CONFLUENCE IS
FAVORED ON LEADING EDGE OF ELY WAVE CROSSING THE SERN STATES.  WHILE
WEAK SHEAR WILL LIMIT ORGANIZATION...SOME STORMS WILL POSE A THREAT
FOR LOCALLY DAMAGING WIND/MARGINALLY SEVERE HAIL.

..CORFIDI/GUYER.. 08/05/2006