Re: Oklahoma Severe Weather Discussion - April 2012
Significant Outbreak Now Being Advertised by SPC...they have already gone Moderate Risk on the Day 3 Outlook. These situations can normally end up with a High Risk. Do not focus completely on Saturday though. We have two very potent days to get through as well.
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0234 AM CDT THU APR 12 2012
VALID 141200Z - 151200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS CENTRAL OK AND ERN KS...
...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
AND EXTENDING ACROSS THE SRN/CENTRAL PLAINS INTO THE UPPER MS
VALLEY...
...POTENTIAL EXISTS FOR A SIGNIFICANT OUTBREAK OF TORNADOES AND VERY
LARGE HAIL ACROSS PARTS OF OK/KS INTO SERN NEB/NWRN MO/SWRN IA...
...SYNOPSIS...
AN AMPLIFIED FLOW PATTERN WILL REMAIN ACROSS THE CONUS THROUGH
D3/SAT...WITH A LARGE TROUGH IN THE WEST AND DOWNSTREAM RIDGE ACROSS
THE ERN STATES. THIS WILL MAINTAIN A CORRIDOR OF STRONG SWLY
MIDLEVEL WIND EXTENDING FROM AZ/NM THROUGH OK/KS INTO THE UPPER MS
VALLEY TO GREAT LAKES REGION. A PACIFIC TROUGH DIGGING SEWD INTO THE
LOWER CO RIVER VALLEY DURING D2/FRI WILL MOVE THROUGH THE BASE OF
THE WRN LONGWAVE TROUGH DURING ON SAT...REACHING CO/NM BY 12Z
SUNDAY. AN ATTENDANT 100 KT MIDLEVEL JET WILL EMERGE INTO THE SRN
HIGH PLAINS TO KS SAT NIGHT...WITH 60-80 KT SWLY MIDLEVEL WINDS
EXPECTED ACROSS MUCH OF THE SLIGHT AND MODERATE RISK AREAS THROUGH
THE FORECAST PERIOD.
AT THE SURFACE...A FRONT IS EXPECTED TO ADVANCE EWD FROM THE UPPER
MIDWEST INTO THE GREAT LAKES...WHILE THE TRAILING PORTION OF THIS
BOUNDARY MOVES SLOWLY SWD ACROSS NEB. A LEE CYCLONE IS FORECAST TO
DEVELOP AND DEEPEN ACROSS ERN CO WITH A WARM FRONT EXTENDING EWD
THROUGH SRN NEB TO SRN IA. THE WARM FRONT WILL SPREAD NEWD INTO THE
UPPER MS VALLEY ON SAT. A DRY LINE WILL MOVE EWD SOME BY SAT
AFTERNOON AND SHOULD EXTEND FROM FAR ERN NEB SSWWD THROUGH CENTRAL
KS TO FAR WRN OK TO THE TX BIG BEND REGION BY LATE SAT AFTERNOON.
...SRN AND CENTRAL PLAINS...
WEAK HEIGHT FALLS ARE EXPECTED ACROSS THE SRN/CENTRAL PLAINS THROUGH
SAT AFTERNOON...WITH STRONGER FALLS FORECAST FOR SAT
EVENING/OVERNIGHT AS THE PACIFIC TROUGH MOVES TOWARD THE SRN AND
CENTRAL HIGH PLAINS. STRONG SLY LOW LEVEL WINDS WILL MAINTAIN
MOISTURE ADVECTION E OF THE DRY LINE ON SAT WITH SURFACE DEWPOINTS
IN THE MID 60S EXPECTED ACROSS MUCH OF OK AND REACHING CENTRAL/ERN
KS BY SAT EVENING. THIS MOISTURE RETURN COUPLED WITH STEEP MIDLEVEL
LAPSE RATES AND STRONG SURFACE HEATING /ESPECIALLY NEAR THE DRY
LINE/ WILL RESULT IN MODERATE TO STRONG INSTABILITY /MLCAPE
2000-2500 J PER KG/ ACROSS THE MODERATE RISK AREA BY LATE AFTERNOON
AND THE SURROUNDING SLIGHT RISK. STRENGTHENING DEEP LAYER WIND
FIELDS...VEERING WITH HEIGHT...WILL RESULT IN STRONG EFFECTIVE BULK
SHEAR /EXCEEDING 50 KT/ AND ORIENTED ACROSS THE DRY LINE. THIS
COMBINED WITH INCREASING LOW LEVEL HODOGRAPH CURVATURE WILL SUPPORT
TORNADIC SUPERCELLS AND THE POTENTIAL FOR VERY LARGE HAIL AND
DAMAGING WINDS. THESE FACTORS COMBINED WITH FAST STORM MOTIONS
SUGGEST THE POTENTIAL FOR LONG-TRACKED...STRONG TORNADOES OCCURRING
FROM THE AFTERNOON THROUGH THE EVENING /INCLUDING AFTER DARK/.
...ERN NEB/IA/NRN MO/NWRN IL/SWRN-SRN WI...
STRENGTHENING SWLY MIDLEVEL WINDS ACROSS THIS REGION THROUGH D3
COMBINED WITH MOISTURE/DESTABILIZATION OCCURRING AS A WARM FRONT
ADVANCES NNEWD SUGGESTS THE ENVIRONMENT WILL BECOME INCREASINGLY
FAVORABLE FOR STRONG TO SEVERE STORMS. MODELS SUGGEST SHORTWAVE
RIDGING ACROSS THIS REGION. HOWEVER..A FEW WEAK IMPULSES EMBEDDED
IN THE STRONGER FLOW ALOFT AND FORCING FOR ASCENT ALONG THE SWD
MOVING FRONT AND INVOF OF THE WARM FRONT SHOULD SUPPORT DEEP MOIST
CONVECTION/TSTMS. MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR OF
40-50 KT WILL FAVOR ORGANIZED STORMS WITH ALL FACETS OF SEVERE
WEATHER POSSIBLE. GREATEST TORNADO THREAT SHOULD BE CONFINED TO THE
WARM FRONT AND ALSO WWD NEAR THE INTERSECTION OF THE DRY LINE WARM
FRONT...WHERE LOW LEVEL SHEAR WILL BE ENHANCED.
..PETERS.. 04/12/2012
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Originally Posted by venture79
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