DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 172002
SWODY1
SPC AC 171959

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0259 PM CDT SUN JUN 17 2012

VALID 172000Z - 181200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF EASTERN
SD...SOUTHEAST ND...AND WESTERN/CENTRAL MN...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE UPPER MS
VALLEY AND NORTHERN PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS WEST-CENTRAL/NORTHWEST
TX...

...EASTERN DAKOTAS/UPPER MIDWEST...
NO CHANGES TO PRIOR FORECAST. SEE MESOSCALE DISCUSSION 1198 FOR
ADDITIONAL DETAILS.

...WEST-CENTRAL/NORTHWEST TX...
PRIOR FORECAST REASONING PERSISTS...ALTHOUGH SOME LIMITED SPATIAL
ADJUSTMENTS WERE MADE BASED ON OBSERVATIONAL TRENDS IN ACCORDANCE
WITH MESOSCALE DISCUSSION 1197.

...LOWER MO RIVER VALLEY...
ADJUSTMENTS WERE MADE TO INCLUDE MORE OF THE REGION IN LOW SEVERE
WIND/HAIL PROBABILITIES. WHILE CONVERGENCE/FORCING FOR ASCENT SHOULD
REMAIN MODEST...ASSORTMENT OF NUMERICAL GUIDANCE INDICATE THE
POTENTIAL FOR TSTM DEVELOPMENT THIS AFTERNOON/EVENING IN VICINITY OF
WARM FRONT/INSTABILITY GRADIENT ACROSS THE REGION. SHOULD THIS
OCCUR...AT LEAST SOME SEVERE THREAT WOULD EXIST GIVEN THE DEGREE OF
INSTABILITY /GENERALLY 2500+ J PER KG MLCAPE/ EVEN WITH WEAK
VERTICAL SHEAR.

...OH VALLEY...
NO CHANGES...SEE DISCUSSION BELOW.

..GUYER.. 06/17/2012

.PREV DISCUSSION... /ISSUED 1124 AM CDT SUN JUN 17 2012/

...UPPER MIDWEST...
A STRONG UPPER TROUGH IS CURRENTLY MOVING ACROSS SASKATCHEWAN AND
EASTERN MT. THIS SYSTEM WILL MOVE ACROSS THE NORTHERN PLAINS AND
BEGIN AFFECTING PARTS OF EASTERN ND/SD AND MN BY LATE THIS AFTERNOON
AND EVENING. AT THE SURFACE 20-30 KNOT SOUTHERLY LOW LEVEL WINDS
ARE HELPING TO TRANSPORT MOISTURE NORTHWARD INTO THE DAKOTAS/MN WITH
DEWPOINTS NOW IN THE MID 60S AS FAR NORTH AS SOUTHEAST SD. A WEAK
SURFACE LOW IS ORGANIZING OVER CENTRAL SD...WHICH SHOULD MOVE
EASTWARD INTO MN LATER TODAY AND PROVIDE THE FOCUS FOR SEVERE
THUNDERSTORM DEVELOPMENT.

SCATTERED THUNDERSTORMS HAVE DEVELOPED ACROSS SOUTHERN MN THIS
MORNING AS WARM ADVECTION AND DESTABILIZATION OCCUR. THESE STORMS
MAY POSE A RISK OF MARGINALLY SEVERE HAIL...BUT THE PRIMARY SEVERE
THREAT IS EXPECTED LATER THIS AFTERNOON. STORMS SHOULD FORM OVER
NORTHEAST SD NEAR SURFACE LOW/WARM FRONT AND TRACK EASTWARD INTO
CENTRAL MN. STRENGTHENING VERTICAL SHEAR PROFILES WILL PROMOTE
SUPERCELLS WITH VERY LARGE HAIL AND A FEW TORNADOES. LOW LEVEL
WINDS WILL CONTINUE TO STRENGTHEN THROUGH THE EVENING AS THE STORMS
TRACK ACROSS THE MODERATE RISK AREA...WITH A CONTINUED THREAT OF
HAIL/TORNADOES. THE POTENTIAL FOR WIDESPREAD DAMAGING WINDS WILL
ALSO INCREASE IF STORMS CAN DEVELOP A COLD POOL AND BEGIN TO
ACCELERATE EASTWARD ALONG THE WARM FRONT. LOW LEVEL DESTABILIZATION
WILL BE THE LIMITING FACTOR TO A MORE LONG-LIVED SIGNIFICANT SEVERE
EVENT FARTHER EAST INTO WI TONIGHT. HOWEVER... POTENTIAL FOR
ISOLATED SEVERE HAIL/WIND WILL PERSIST WELL AFTER DARK.

CONSIDERABLE UNCERTAINTY EXISTS REGARDING HOW FAR SOUTH THE STORMS
WILL FORM INTO SOUTHERN MN OR IA. MOST MODEL SOLUTIONS CONTINUE TO
TREND MORE NORTH WITH TIME...AND HAVE ATTEMPTED TO ADJUST FORECAST
AREAS TO REFLECT THIS.

...TX...
A BAND OF RELATIVELY STRONG NORTH-NORTHWEST FLOW ALOFT HAS DEVELOPED
ACROSS WEST-CENTRAL TX TODAY. THIS IS CO-LOCATED WITH MODERATELY
STRONG SOUTHERLY LOW LEVEL WINDS AND AMPLE MOISTURE/CAPE. SCATTERED
THUNDERSTORMS ARE EXPECTED TO FORM IN THIS AREA LATER TODAY...WITH
STEEP LOW LEVEL LAPSE RATES AND GREATER CONVECTIVE ORGANIZATION
SUGGESTING A RISK OF LOCALLY DAMAGING WINDS AND HAIL.

...OH VALLEY...
SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST TO DEVELOP THIS
AFTERNOON ALONG AN AXIS FROM OH/WESTERN PA INTO KY/TN. A MOIST AND
MODERATELY UNSTABLE AIR MASS IS IN PLACE ACROSS THIS REGION...WITH A
FEW INTENSE STORMS POSSIBLE. GUSTY WINDS AND HAIL WILL BE POSSIBLE
IN THE STRONGEST CORES...ALTHOUGH ORGANIZED SEVERE STORMS ARE NOT
CURRENTLY ANTICIPATED.

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