Monday, July 14, 2008

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 150050
SWODY1
SPC AC 150048

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0748 PM CDT MON JUL 14 2008

VALID 150100Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NRN MN...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL NEB...

...NRN MN...
WATER VAPOR AND RUC ANALYSIS SHOW WEST TO NORTHWEST FLOW IN PLACE
ACROSS THE NRN U.S. WITH A SHORTWAVE TROUGH LOCATED ACROSS SWRN
ONTARIO. AT THE SFC...A COLD FRONT IS MOVING SEWD ACROSS NRN MN WITH
A LINE OF STORMS DEVELOPING JUST AHEAD OF THE BOUNDARY. A SMALL
POCKET OF MOISTURE IS LOCATED NEAR THE THUNDERSTORM ACTIVITY WHERE
SFC DEWPOINTS ARE IN THE LOWER TO MID 60S F. THIS IS CONTRIBUTING TO
ABOUT 1000 J/KG OF SBCAPE. THIS ALONG WITH INCREASING BOUNDARY LAYER
FLOW DUE TO A DEVELOPING LOW-LEVEL JET OVER NRN MN SHOULD RESULT IN
A GRADUAL INCREASE IN STORM COVERAGE SWWD INTO NWRN MN THIS EVENING.
FORECAST SOUNDINGS ACROSS THE REGION THIS EVENING SHOW STRONG
VERTICAL SHEAR WITH STEEP MID-LEVEL LAPSE RATES OF ABOUT 7.5 C/KM.
THIS SUGGESTS LARGE HAIL WILL BE POSSIBLE ESPECIALLY WITH ROTATING
STORMS THAT DEVELOP. IN ADDITION...RUC DATA INDICATE 0-3 KM LAPSE
RATES RANGE FROM 7.5 TO 8.0 C/KM SUGGESTING ISOLATED WIND DAMAGE MAY
ALSO OCCUR.

...CNTRL NEB...
WATER VAPOR IMAGERY CURRENTLY SHOWS A VERY SUBTLE SHORTWAVE TROUGH
OVER CNTRL NEB WHERE A SMALL CONVECTIVE CLUSTER IS ONGOING ATTM. THE
STORMS ARE LOCATED NEAR A SFC LOW WHERE CONVERGENCE IS MAXIMIZED.
THE CONVECTION SHOULD CONTINUE ENEWD ALONG AN AXIS OF MODERATE
INSTABILITY EXTENDING NEWD INTO THE NORFOLK NEB AREA. REGIONAL
PROFILERS SUGGEST SUBSTANTIAL DIRECTIONAL SHEAR EXISTS BELOW 3 KM IN
THE VICINITY OF THE STORMS WITH ABOUT 40 KT OF 0-6 KM SHEAR. THIS
SHOULD BE ADEQUATE TO CONTINUE A SEVERE THREAT WITH THE BOWING LINE
SEGMENT FOR A FEW MORE HOURS. STEEP MID-LEVEL LAPSE RATES SHOULD BE
SUFFICIENT FOR HAIL. ISOLATED WIND DAMAGE MAY ALSO OCCUR AS
LOW-LEVEL FLOW INCREASES EARLY THIS EVENING.

..BROYLES.. 07/15/2008

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