DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 021737
SWODY2
SPC AC 021736

DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
1236 PM CDT SAT JUN 02 2012

VALID 031200Z - 041200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS ERN KS...PARTS OF NRN OK
AND WRN MO...

CORRECTED FOR WORDING IN FOURTH PARAGRAPH

...SYNOPSIS...
A DOWNSTREAM REX BLOCK OVER THE NRN ATLANTIC/GREENLAND PERSISTING
FOR AT LEAST ONE MORE DAY...AND HEIGHT RISES WSWWD INTO NRN
QUEBEC/HUDSON BAY AND ADJACENT NRN ONTARIO ON SUNDAY...WILL ALLOW
THE CLOSED LOW LOCATED JUST N OF THE GREAT LAKES TO PROGRESS SEWD
ACROSS THE NERN STATES. MEANWHILE...A PACIFIC SHORTWAVE TROUGH...
CURRENTLY LOCATED AT 39 N/147 W PER WATER VAPOR IMAGERY...WILL MOVE
INTO THE BASE OF THE GULF OF AK CLOSED LOW...AIDING THE
AMPLIFICATION OF THESE SYSTEMS TOWARD THE WRN CONUS. THE SLOW EWD
PROGRESSION OF THE NERN U.S. TROUGH AND AMPLIFICATION OF THE PACIFIC
LONGWAVE TROUGH SUPPORT RIDGING ACROSS THE ROCKIES AND PLAINS
STATES.

AT THE SURFACE...A BOUNDARY...ATTENDANT TO A SHORTWAVE TROUGH MOVING
INTO THE LOWER OH VALLEY TODAY...CURRENTLY EXTENDED FROM WRN IL
WSWWD THROUGH CENTRAL MO TO KS. THE SEWD PROGRESSION OF THE EWD
EXTENT OF THIS BOUNDARY INTO THE TN VALLEY AND A NWD MOVING WARM
FRONT FROM OK AND AR ARE EXPECTED TO FORM THE EFFECTIVE SURFACE
BOUNDARY FOR DAY 2. THE PRIMARY FOCUS FOR TSTM DEVELOPMENT IS
EXPECTED TO BE THIS BOUNDARY EXTENDING NWWD FROM NRN AL/MS THROUGH
NRN AR/SWRN MO TO A DEVELOPING SURFACE LOW/TRIPLE POINT OVER NORTH
CENTRAL KS BY SUNDAY AFTERNOON.

...KS/NRN OK...MID-LOWER MO VALLEY...AND PART OF TN VALLEY...
A SHORTWAVE TROUGH WITH A COUPLE OF EMBEDDED MID/UPPER LEVEL
IMPULSES CURRENTLY UNDERCUTTING THE RIDGE AXIS INTO THE FOUR CORNERS
REGION SHOULD BE LOCATED IN THE CENTRAL PLAINS AT THE START OF DAY
2. MODELS TEND TO AGREE WITH THE PLACEMENT AND TRACK OF THESE WEAK
IMPULSES ON SUNDAY...MOVING ESEWD WITHIN NWLY FLOW REGIME ALONG THE
ERN EXTENT OF THE ROCKIES/PLAINS RIDGE. THESE FEATURES SHOULD MOVE
ACROSS KS AND LOWER MO/MID MS VALLEYS AREAS SUNDAY AFTERNOON AND
INTO OK...OZARKS TO TN VALLEY LATE SUNDAY NIGHT.

A STRONG EML SPREADING EWD ATOP MOISTENING LOW LEVELS AND SURFACE
HEATING WILL RESULT IN A VERY UNSTABLE AIR MASS ACROSS THE WARM
SECTOR /KS INTO OK/ AND MODERATE INSTABILITY EXTENDING SEWD ACROSS
THE OZARKS TO WRN TN/NRN MS/NRN AL AND ALSO NWD THROUGH THE MID MO
VALLEY. WHILE THE STRONG CAP/EML SHOULD LIMIT WARM SECTOR
CONVECTION...CONVERGENCE AND LOW LEVEL WAA ALONG THE SE-NW ORIENTED
SURFACE BOUNDARY WILL LIKELY SUPPORT TSTM DEVELOPMENT. PERSISTENT
DEVELOPMENT SHOULD RESIDE ACROSS ERN KS/WRN MO INTO NERN OK WHERE A
SLY LLJ WILL BE LOCATED. THUS...STRONGEST BULK SHEAR IS EXPECTED
ACROSS THE SLIGHT RISK AREA WITH THE POTENTIAL FOR SUPERCELLS.
MULTICELLS SHOULD BE THE PRIMARY STORM MODE BOTH WITH SEWD EXTENT
INTO TN/NRN MS/NRN AL AND NWD INTO THE MID MO VALLEY WHERE BULK
SHEAR WILL TEND TO BE WEAKER.

A VEERING LLJ INTO MO/OZARKS/ERN OK SUNDAY NIGHT SUGGESTS AN MCS MAY
PERSIST AFTER DARK WITH SOME THREAT FOR ADDITIONAL SEVERE STORMS.

...PARTS OF SRN PA...ERN WV...FAR NRN VA AND NRN MD...
DAYTIME HEATING BENEATH COOL MID-LEVEL TEMPERATURES ASSOCIATED WITH
THE UPPER LOW WILL RESULT IN MODEST/LOW-TOPPED CONVECTION PER
GREATEST DESTABILIZATION NEAR PEAK HEATING. GIVEN THE POTENTIAL FOR
STRONGER DESTABILIZATION...THOUGH STILL WEAK WITH EWD EXTENT INTO
SERN PA AND NRN MD...THE 5 PERCENT SEVERE PROBABILITY HAS BEEN
EXTENDED EWD WITH THIS OUTLOOK ISSUANCE. CURRENT MODELS SUGGEST AN
EWD SHIFT FOR THE GREATER POTENTIAL OF A FEW STRONGER STORMS TO
DEVELOP WITHIN NWLY FLOW AND AROUND 30 KT OF BULK SHEAR. MIDLEVEL
LAPSE RATES CLOSE TO 7 C/KM AND STEEP LOW LEVEL LAPSE RATES...
ESPECIALLY OVER NRN VA TO SERN PA...SUGGEST HAIL AND STRONG WIND
GUSTS WILL BE POSSIBLE WITH THE MORE ROBUST UPDRAFTS. WEAK
INSTABILITY WILL PRECLUDE INTRODUCING HIGHER PROBABILITIES/
CATEGORICAL RISK AT THIS TIME.

..PETERS.. 06/02/2012

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