SPC AC 010549
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1249 AM CDT WED JUN 01 2011
VALID 021200Z - 031200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM NERN MT THROUGH ND INTO
NRN MN...
...SYNOPSIS...
UPPER TROUGH WILL ADVANCE SLOWLY EWD THROUGH THE WRN STATES WITH A
SIGNIFICANT IMPULSE FORECAST TO EJECT THROUGH THE NRN HIGH PLAINS
THURSDAY AFTERNOON. A SUBTROPICAL HIGH PRESSURE WILL REMAIN
ENTRENCHED OVER THE SRN PLAINS AND SERN U.S. WHILE UPPER TROUGH OVER
THE NERN STATES CONTINUES OFFSHORE. AT THE SURFACE A WARM FRONT WILL
LIFT THROUGH THE UPPER MS VALLEY AND NRN PLAINS WHILE A COLD FRONT
ADVANCES EWD THROUGH THE NRN HIGH PLAINS. FARTHER EAST A COLD FRONT
WILL ADVANCE SLOWLY SWD THROUGH INTO TN AND NC.
...NRN HIGH PLAINS THROUGH UPPER MS VALLEY AREA...
A RELATIVELY NARROW MOIST AXIS WILL LIFT NWD INTO THE NRN PLAINS IN
WAKE OF WARM FRONT THAT WILL EXTEND FROM SURFACE LOW IN ERN MT SEWD
INTO THE MIDDLE-UPPER MS VALLEY EARLY THURSDAY. ELEVATED STORMS WILL
BE ONGOING FROM ND SEWD THROUGH IA AND MO WITHIN ZONE OF ISENTROPIC
LIFT NORTH OF WARM FRONT. SOME OF THESE STORMS MIGHT POSE A THREAT
FOR HAIL AS THEY SHIFT NEWD. WARM SECTOR WILL GRADUALLY EXPAND NWD
DURING THE DAY ALONG WITH A WARM EML /700 MB TEMPERATURES AOA 10C/.
THIS IN CONJUNCTION WITH SHORTWAVE RIDGING LOWERS CONFIDENCE THAT
SURFACE BASED STORMS WILL BE ABLE TO DEVELOP ALONG CONVECTIVELY
REINFORCED WARM FRONT. IF SURFACE BASED STORMS WERE TO FORM...LARGE
HODOGRAPHS ALONG NOSE OF THE LLJ WOULD SUPPORT SUPERCELLS FROM ERN
PORTIONS OF THE NRN PLAINS INTO THE UPPER MS VALLEY.
OTHERWISE...ELEVATED STORMS COULD INTENSIFY OVER THE UPPER MS VALLEY
AND NRN PLAINS AND POSE A THREAT FOR LARGE HAIL AS THEY ENCOUNTER
INCREASINGLY UNSTABLE INFLOW FROM THE WARM SECTOR. HAVE EXPANDED THE
SLIGHT RISK AREA EWD ACROSS ND INTO NWRN MN PRIMARILY FOR A THREAT
OF LARGE HAIL WITH ELEVATED STORMS. DUE TO CAPPING CONCERNS ONLY 15%
SEVERE PROBABILITIES WILL BE INTRODUCED AT THIS TIME.
IT STILL APPEARS SURFACE BASED STORM INITIATION IS A LITTLE MORE
PROBABLE ALONG EWD SURGING COLD FRONT FROM ERN MT INTO WRN ND WHERE
DIABATIC WARMING AND DEEPER FRONTAL CIRCULATION WITHIN UPPER JET
EXIT REGION MAY ERODE THE CAP. STEEP LAPSE RATES...1000-1500 J/KG
MLCAPE ALONG MOIST AXIS AND STRONG EFFECTIVE SHEAR /50+ KT/ WOULD
PROMOTE SUPERCELLS AND BOWING SEGMENTS WITH ANY STORMS THAT DEVELOP.
...CNTRL THROUGH SRN HIGH PLAINS...
STRONG DIABATIC WARMING WILL PROMOTE DEEP MIXING AND WEAKENING
CONVECTIVE INHIBITION OVER THE SRN THROUGH CNTRL HIGH PLAINS IN
VICINITY OF LEE TROUGH. CAPE WILL REMAIN SOMEWHAT LIMITED DUE TO
MODEST LOW LEVEL MOISTURE...BUT SOME OF THE HIGH BASED STORMS MAY
PRODUCE ISOLATED DOWNBURSTS AND MARGINALLY SEVERE HAIL.
...SERN STATES...
SCATTERED STORMS ARE EXPECTED TO DEVELOP DURING THE AFTERNOON AS
DIABATIC WARMING AND MODERATELY STEEP MID LEVEL LAPSE RATES
CONTRIBUTE TO 2000-2500 J/KG MLCAPE. WEAK VERTICAL SHEAR WILL EXIST
IN PROXIMITY TO UPPER RIDGE...BUT THE STRONGER PULSE AND MULTICELL
STORMS COULD PRODUCE ISOLATED DOWNBURSTS AND HAIL.
..DIAL.. 06/01/2011
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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