SWODY3
SPC AC 080712
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0212 AM CDT SUN MAY 08 2011
VALID 101200Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF ERN ND AND
CNTRL/NRN MN...
...SYNOPSIS...
WRN STATES UPPER TROUGH WILL BEGIN TO MIGRATE ENE ACROSS THE PLAINS
ON TUESDAY AS A NEW IMPULSE DIGS SEWD FROM THE GULF OF AK. THE
TROUGH WILL BE COMPOSED OF TWO PRIMARY SHORTWAVE TROUGHS. ONE
DISTURBANCE WILL CONTINUE ENE FROM THE NRN PLAINS TOWARD NWRN
ONTARIO LATE ON TUESDAY WHILE A SECOND JETLET BEGINS TO TRANSLATE
ACROSS THE SRN ROCKIES TO THE CNTRL/SRN HIGH PLAINS BY LATE IN THE
PERIOD.
...ERN ND/CNTRL-NRN MN...
LOWER THAN AVERAGE CONFIDENCE EXISTS AS MODELS HAVE NOT BEEN
CONSISTENT ON THE HANDLING OF THE NRN PORTIONS OF THE EJECTING WRN
STATES UPPER TROUGH. CURRENT THINKING IS THAT A SFC LOW ATTENDANT
TO THE LEAD MID-LEVEL IMPULSE WILL TRAVEL ACROSS CNTRL ND TOWARD
NWRN MN BY TUESDAY EVE. SMALL WARM SECTOR...CHARACTERIZED BY 1500+
J/KG MLCAPE...WILL PROBABLY EVOLVE ALONG/E OF A SURGING
DRYLINE/FRONT FROM THE UPR MS VLY WNW TO ERN ND BY AFTN. EXPECT
INITIAL STORMS MAY INITIATE AMID WEAKER CINH/STRONGER ASCENT NEAR
THE TRIPLE POINT ERN ND BY MID-AFTN...THEN EVOLVE ESE ALONG THE
DRYLINE/FRONT INTO CNTRL MN BY LATE AFTN. POTENTIALLY 50 KTS OF
EFFECTIVE SHEAR AND 6.5+ DEG C PER KM H5-H7 LAPSE RATES WILL BE
FAVORABLE FOR MIXED CONVECTIVE MODES GIVING LARGE HAIL...DMGG WINDS
AND A COUPLE OF TORNADOES.
...PLAINS...
EML WILL REMAIN STRONG ACROSS THE PLAINS ON TUESDAY WITH PRIMARY
MASS CONVERGENCE LIKELY RELEGATED TO THE EJECTING NRN PLAINS WAVE.
IN FACT...PREFERRED SLOWER TIMING OF THE SECONDARY IMPULSE MOVING
ACROSS THE SRN ROCKIES ON TUESDAY/TUESDAY NIGHT SUGGESTS THAT WEAK
LARGE-SCALE RIDGING MAY DOMINATE DOWNSTREAM AND LIMIT PROBABILITIES
OF TSTMS ALTOGETHER ACROSS THE PLAINS THROUGH MOST OF TUESDAY.
GIVEN A SLOWER TIMING OF THIS WAVE...EXPECT THAT MOST STORM CHANCES
WILL EXIST TUESDAY NIGHT...BOTH ALONG THE A WEAK WIND SHIFT SETTLING
SWD INTO NRN KS/SERN NEB AND ALONG WRN PERIPHERY OF LOW-LEVEL MOIST
AXIS FROM TX BIG BEND NWD INTO WRN OK. LOW-END SVR PROBABILITIES
WILL EXIST IN THESE REGIONS SINCE EVEN NOCTURNAL STORMS MAY OFFER A
LARGE HAIL THREAT. LARGE DEGREE OF UNCERTAINTY PRECLUDES HIGHER
PROBABILITIES AT THIS TIME.
...SERN STATES...
AS LARGE SCALE RIDGE AMPLIFIES DOWNSTREAM OF THE WRN STATES
TROUGH...HEIGHT GRADIENT WILL TIGHTEN AND CONTRIBUTE TO A
CONCOMITANT ENHANCEMENT OF THE NWLY LOW/MID-LEVEL FLOW REGIME.
DIURNALLY-BASED STORMS...POSSIBLY AIDED BY WEAK MID-LEVEL WAVES
CRESTING THE RIDGE...WILL LIKELY FORM VCNTY A BACKDOOR FRONT
EXPECTED TO LAY FROM SC NWWD INTO THE CNTRL APPALACHIANS. WEAK WNW
LLJ BRANCH FEEDING THE STORMS WILL BE EMANATING FROM A VERY STEEP
LAPSE RATE UPSTREAM ENVIRONMENT AND GIVEN ANTICIPATED KINEMATIC
SET-UP...AT LEAST ISOLD ORGANIZED STORMS WITH LARGE HAIL/GUSTY WINDS
WILL BE POSSIBLE.
..RACY.. 05/08/2011
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