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SPC 0100Z Day 1 Outlook

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0739 PM CDT FRI MAY 18 2012

VALID 190100Z - 191200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS EVE ACROSS PARTS OF
CENTRAL SOUTH DAKOTA...

...SYNOPSIS/SOUTH DAKOTA...
SCATTERED AREAS OF THUNDERSTORM ACTIVITY ACROSS THE NATION ALREADY
APPEAR GENERALLY ON THE WANE.  ONE EXCEPTION COULD BE RECENT NEW
STORM DEVELOPMENT NEAR A WEAK SURFACE LOW ACROSS SOUTH CENTRAL SOUTH
DAKOTA...WHICH MAY BE AIDED BY A DIVERGENT UPPER FLOW FIELD SHIFTING
ACROSS AND EAST OF THE NORTH CENTRAL HIGH PLAINS THIS EVENING.  THE
BOUNDARY LAYER IN THE WARM SECTOR OF THIS LOW...AND AHEAD OF AN
ASSOCIATED SURFACE FRONT EXTENDING NORTHEASTWARD THROUGH
SOUTHEASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA... REMAINS
WARM...AND POTENTIALLY UNSTABLE WITH CAPE ON THE ORDER OF 1000-1500+
J/KG.  THERMODYNAMIC PROFILES ARE CHARACTERIZED BY STEEP LOW-LEVEL
LAPSE RATES AND SIZABLE SUB-CLOUD TEMPERATURE DEW POINT
SPREADS...WHICH WILL SUPPORT POTENTIAL FOR STRONG CONVECTIVELY
GENERATED SURFACE GUSTS...WHICH COULD BECOME ENHANCED BY THE
DOWNWARD TRANSFER OF MOMENTUM ASSOCIATED WITH A STRENGTHENING
SOUTHERLY 850 MB JET.  WEAK LOW-LEVEL FORCING IS EXPECTED TO LIMIT
THE DURATION OF THE SEVERE THREAT THIS EVENING...BUT IT DOES APPEAR
THAT DAMAGING WIND POTENTIAL COULD STILL INCREASE FOR A PERIOD THIS
EVENING ACROSS CENTRAL SOUTH DAKOTA...BEFORE DIMINISHING AFTER
03-04Z.

..KERR.. 05/19/2012

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MD 0834 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CNTRL SD

MESOSCALE DISCUSSION 0834
NWS STORM PREDICTION CENTER NORMAN OK
0722 PM CDT FRI MAY 18 2012

AREAS AFFECTED...CNTRL SD

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 190022Z - 190245Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED SEVERE STORMS WILL REMAIN LIKELY...BUT COVERAGE
MAY BE TOO LOW FOR A WATCH.

DISCUSSION...A SUPERCELL IS CURRENTLY ONGOING OVER JACKSON COUNTY
SD...ON THE SURFACE FRONT. OBSERVED 00Z SOUNDINGS SHOW VERY STEEP
LAPSE RATES IN PLACE WITH MODEST SLY FLOW ALOFT. HELPING TO AUGMENT
HODOGRAPH LENGTH ARE THE NLY WINDS BEHIND THE FRONT. IN THIS
CASE...WITH DEWPOINTS IN THE MID 50S NEAR THE BOUNDARY...THE AIR IS
STILL UNSTABLE DESPITE BEING COOLER. THEREFORE...THE ENTIRE
HODOGRAPH IS EFFECTIVE...PROVIDING A FAVORABLE PROFILE FOR SEVERE
STORMS. LARGE HAIL IS LIKELY AND DAMAGING WINDS MAY ALSO OCCUR AS
THIS CELL DEVELOPS NEWD ALONG THE BOUNDARY. 

OTHER ACTIVITY CONTINUES OVER NWRN NEB...BUT CURRENTLY WELL AHEAD OF
THE FRONT. IT IS POSSIBLE THAT OTHER CELLS ZIPPER SWD ALONG THE
ADVANCING COLD FRONT INTO S CNTRL OR N CNTRL NEB LATER THIS
EVENING....ALTHOUGH CIN WILL BE INCREASING.

..JEWELL/MEAD.. 05/19/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FSD...ABR...UNR...

LAT...LON   43560091 43510164 43720179 44180152 44810067 45030017
            45039937 44759883 44309863 44039866 43749881 43629975
            43560091 

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