SPC AC 100537
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1237 AM CDT FRI SEP 10 2010
VALID 101200Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE
CNTRL/SRN PLAINS...
...SYNOPSIS...
UPPER TROUGH MOVING ONTO THE HIGH PLAINS EARLY FRIDAY MORNING WILL
CONTINUE EWD REACHING THE CORN BELT AND MID-UPPER MS VALLEY BY 12Z
SATURDAY. ASSOCIATED COLD FRONT WILL SWEEP EWD FROM THE HIGH PLAINS
EARLY IN THE PERIOD...EVENTUALLY OVERTAKING THE LEE TROUGH/DRYLINE
OVER THE MO VALLEY/CNTRL PLAINS BY LATE AFTERNOON. MEANWHILE...AN
E-W ORIENTED FRONT WILL REMAIN ESSENTIALLY IN PLACE FROM CNTRL MO
INTO THE TN VALLEY.
...CNTRL/SRN PLAINS TO MID-MS VALLEY...
AIR MASS AHEAD OF THE DRYLINE/LEE TROUGH AND SW OF THE FRONT IN
CNTRL MO WILL BECOME STRONGLY UNSTABLE FRIDAY AFTERNOON AS LOWER 70S
SURFACE DEW POINTS RESIDE BENEATH 7.5 DEG C PER KM MID-LEVEL LAPSE
RATES. MLCAPES WILL RANGE FROM 2500-3500 J/KG FROM CNTRL OK NWD TO
ERN KS AND WRN/SRN MO.
ALTHOUGH SRN FRINGES OF LARGE-SCALE HEIGHT FALLS ARE NOT EXPECTED
UNTIL AFTER DARK...STRONG BOUNDARY LAYER HEATING AND SLOWLY
INCREASING CONVERGENCE INVOF THE LEE TROUGH/DRYLINE WILL YIELD
SURFACE-BASED STORM INITIATION BY MID-AFTERNOON. THIS APPEARS MOST
LIKELY FROM NEAR THE THREE STATE BORDERS OF NE...KS...MO WITH
SUBSEQUENT BACKBUILDING/DEVELOPMENT SWWD INTO AT LEAST NCNTRL OK.
DEEP-LAYER SHEAR WILL INITIALLY BE 30-35 KTS BUT STRONG INSTABILITY
WILL COMPENSATE FOR FIRST STORMS TO GROW INTO SUPERCELLS WITH LARGE
HAIL AND PERHAPS A TORNADO OR TWO. AS THE UPPER TROUGH
APPROACHES...WIND FIELDS WILL IMPROVE...BUT BY THEN...ACTIVITY
SHOULD EVOLVE INTO CLUSTERS OR SEMI-ORGANIZED LEWPS WHILE MOVING ESE
INTO WRN/SRN MO. DAMAGING WINDS AND HAIL WILL BECOME THE PRIMARY
THREATS DURING THE EVENING OVER THE OZARKS.
...MO VALLEY/ERN DAKOTAS...
EARLIER FORECAST REASONING IS UNCHANGED WITH CONSIDERABLY LESSER
OPPORTUNITY/DEGREE OF DESTABILIZATION ALONG NRN END OF THE COLD
FRONT/OCCLUSION. HERE...MOISTURE CORRIDOR WILL BE NARROW WITH
INSTABILITY COMPARATIVELY WEAKER THAN FARTHER S /MLCAPES TO 500 J
PER KG/. IN WAKE OF A FEW ELEVATED MORNING STORMS...A COUPLE OF
STRONGER STORMS MAY DEVELOP DURING THE AFTERNOON INVOF THE FRONT.
HAIL OR GUSTY WINDS MAY ACCOMPANY THESE STORMS...BUT RISKS SEEM
SMALL ENOUGH TO PRECLUDE A SLIGHT RISK.
..RACY/SMITH.. 09/10/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
|
