SPC AC 090725
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0225 AM CDT FRI JUL 09 2010
VALID 111200Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE WRN GREAT LAKES INTO
THE CENTRAL PLAINS...
...SYNOPSIS...
BROAD CYCLONIC FLOW PATTERN IS FORECAST TO SPREAD ACROSS MUCH OF THE
N CNTRL AND NERN US ON SUNDAY AS THE PRIMARY SHORT WAVE TROUGH MOVES
EWD FROM MAN INTO ONT...WHILE FARTHER SOUTH MODEL GUIDANCE SUGGESTS
A SERIES OF WEAKER PERTURBATIONS MOVING EWD ACROSS THE N CNTRL
STATES. A SURFACE COLD FRONT IS EXPECTED TO MOVE EWD AND SEWD
ACROSS THE UPPER MS VALLEY/WRN GREAT LAKES EXTENDING SWWD INTO THE
CNTRL PLAINS.
...WRN GREAT LAKES INTO THE CNTRL PLAINS...
AMPLE MOISTURE IS FORECAST AHEAD OF THE ADVANCING COLD FRONT WITH
SURFACE DEW POINTS RANGING FROM THE 60S OVER NRN MN/WI TO THE LOW
70S OVER THE CENTRAL PLAINS/LOWER MO VALLEY. ACTIVE CONVECTION MAY
BE ONGOING EARLY IN THE PERIOD FROM WRN LAKE SUPERIOR SWWD INTO
PARTS OF WRN IA/ERN NEB...ALTHOUGH THERE IS UNCERTAINTY REGARDING
DEGREE AND EXTENT OF STORM WEAKENING PRIOR TO THE MAIN AFTERNOON
HEATING PERIOD. DYNAMIC FORCING ASSOCIATED WITH THE CANADIAN SHORT
WAVE TROUGH WILL AFFECT THE NRN PART OF THE RISK AREA. STRONGER
CELLS WILL BE CAPABLE OF PRODUCING STRONG WINDS AND LARGE HAIL
MAINLY DURING THE DAY...WITH THE SEVERE THREAT EXPECTED TO DIMINISH
BY EVENING.
FARTHER SOUTH...MODEL GUIDANCE IS CONSISTENT PREDICTING SUBSTANTIAL
OVER PARTS OF THE CENTRAL PLAINS AND LOWER MO VALLEY WITH MLCAPE AOA
2000 J/KG DURING THE AFTERNOON AND EVENING. STORMS ARE LIKELY TO
REDEVELOP AND INTENSIFY ALONG/AHEAD OF THE COLD FRONT ESPECIALLY
OVER PARTS OF NEB/KS AND WRN IA. VEERING WIND PROFILES WITH HEIGHT
AND WNWLY MID LEVEL WINDS OF 30-40 KT WILL CONTRIBUTE TO SUFFICIENT
VERTICAL SHEAR /35-40 KT IN THE LOWEST 6 KM/ TO ENHANCE STORM
ORGANIZATION AND INTENSITY. THIS SUGGESTS A FAVORABLE ENVIRONMENT
FOR SEVERE STORMS INCLUDING A FEW SUPERCELLS. THE ACTIVITY MAY GROW
UPSCALE INTO ONE OR MORE MCS/S BY EVENING AS CONVECTION SPREADS EWD
DURING THE OVERNIGHT HOURS WITH A CONTINUING THREAT FOR A FEW SEVERE
STORMS.
..WEISS.. 07/09/2010
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
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