993
ACUS03 KWNS 080731
SWODY3
SPC AC 080728
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT TUE JUL 08 2008
VALID 101200Z - 111200Z
..THERE IS A SLGT RISK OF SVR TSTMS ACROSS NERN ND AND NRN MN
..SYNOPSIS
FAIRLY INTENSE SHORTWAVE TROUGH IS FORECAST TO MOVE EWD INTO SRN
SASKATCHEWAN/MANITOBA BY LATE IN THE PERIOD. A 60-70 KT MID LEVEL
JET WILL BE LOCATED ALONG THE SRN PERIPHERY OF THIS SYSTEM AND
SPREAD FROM MT EWD INTO ND/NRN MN. AT THE SURFACE...A LOW PRESSURE
SYSTEM WILL SHIFT EWD FROM MT INTO N CENTRAL ND BY LATE AFTERNOON
..WITH A COLD FRONT EXTENDING SWWD FROM THE LOW INTO NERN WY
AND
A WARM FRONT STRETCHING EWD ACROSS NRN MN.
..NERN ND AND NRN MN
MORNING CONVECTION IS LIKELY EARLY MORNING...DUE TO STRONG LOW LEVEL
WARM ADVECTION ABOVE A RELATIVELY DRY AND STABLE BOUNDARY LAYER.
HOWEVER...THIS CONVECTION SHOULD SHIFT NEWD INTO SRN ONTARIO/NRN
GREAT LAKES AS WARM ADVECTION LIFTS NWD OUT OF THE AREA. BY
AFTERNOON...AIR MASS IS FORECAST TO BECOME STRONGLY UNSTABLE AS
STRENGTHING SLY WINDS ADVECT MID AND UPPER 60S DEWPOINTS NWD FROM
THE CENTRAL PLAINS. INCREASINGLY WLY WIND ALOFT SHOULD WARM MID
LEVEL TEMPERATURES AND STRENGTHEN CAPPING INVERSION. SINCE LARGE
SCALE FORCING AND HEIGHT FALLS ARE EXPECTED TO BE MINIMAL...STORM
DEVELOPMENT MAY BE RESTRICTED IN THE WARM SECTOR AND LIMITED TO NEAR
THE SURFACE LOW AND WARM FRONT WHERE CONVERGENCE WILL BE THE
STRONGEST DUE TO 25-35 KT LOW LEVEL JET. ONCE STORMS DEVELOP...THE
DEGREE OF INSTABILITY AND 60-70 KT MID LEVEL WINDS WILL PROVIDE
FAVORABLE INSTABILITY/SHEAR FOR SUPERCELLS WITH A POTENTIAL FOR HAIL
AND DAMAGING WINDS.
..SERN VA/ERN NC WSWWD INTO AR/MS
REMNANT FRONT/LEE TROUGH IS FORECAST TO EXTEND FROM SERN VA/ERN NC
WSWWD INTO SRN AR/NRN MS ON THU. ALSO...SHORTWAVE TROUGH MOVING EWD
THROUGH NEW ENGLAND...WILL RESULT IN MID/HIGH LEVEL TROPICAL
MOISTURE PLUME...CURRENTLY LOCATED ACROSS THE MID/UPPER MS
VALLEY...TO SHIFT EWD ACROSS THIS REGION. CONVERGENCE ALONG WEAK
SURFACE BOUNDARY AND MOIST ENVIRONMENT SHOULD BE SUFFICIENT FOR
SCATTERED THUNDERSTORMS...MOST NUMEROUS DURING THE AFTERNOON/EARLY
EVENING HOURS. A MODERATELY UNSTABLE ENVIRONMENT AND RELATIVELY
STEEP LOW LEVEL LAPSE RATES SHOULD SUPPORT A FEW STRONG WIND GUSTS
...THOUGH WEAK SHEAR AND POOR MID LEVEL LAPSE RATES INDICATE THE
THREAT SHOULD BE ISOLATED AND SHORT LIVED.
..IMY.. 07/08/2008
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