SPC AC 240551
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1251 AM CDT THU JUN 24 2010
VALID 241200Z - 251200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE MID
ATLANTIC INTO THE NERN STATES...
...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NRN
PLAINS...
...SYNOPSIS...
A PROGRESSIVE SHORTWAVE TROUGH MOVING INTO THE UPPER GREAT LAKES
WILL ADVANCE THROUGH THE NERN STATES THURSDAY. ATTENDANT SURFACE LOW
WILL DEEPEN OVER SERN QUEBEC WHILE TRAILING COLD FRONT PUSHES SEWD
THROUGH THE NERN STATES...OH AND TN VALLEYS. SWRN EXTENSION OF FRONT
WILL STALL OVER THE SRN PLAINS. FARTHER WEST A POSITIVE TILT UPPER
TROUGH WILL PERSIST NEAR THE WRN U.S. COAST WITH A DOWNSTREAM RIDGE
OVER THE CNTRL AND NRN PLAINS. DEEPER BAROCLINIC ZONE WILL REMAIN
FROM S-CNTRL CANADA INTO THE NRN PLAINS AND UPPER MS VALLEY WITH A
LEE TROUGH OVER THE CNTRL AND NRN HIGH PLAINS.
...NERN THROUGH MID ATLANTIC STATES...
MCS CURRENTLY ONGOING COMPLICATES THIS FORECAST SOMEWHAT. FORWARD
PROPAGATING PORTION OF MCS NOW MOVING THROUGH ERN OH IS EXPECTED TO
CONTINUE A WEAKENING TREND INTO THE EARLY MORNING AS IT MOVES EWD
INTO A LESS UNSTABLE AIR MASS. OTHER STORMS ALONG WARM ADVECTION
WING ACROSS SWRN NY WILL SHIFT ENEWD OVERNIGHT INTO CNTRL/ERN NY BY
12Z THURSDAY. BEST DESTABILIZATION POTENTIAL WILL EXIST SOUTH OF
THIS ACTIVITY FROM SERN NY...SRN NEW ENGLAND INTO THE MID ATLANTIC
WHERE STRONGER DIABATIC HEATING OF THE BOUNDARY LAYER WILL
CONTRIBUTE TO MODERATE INSTABILITY /1500-2000 J/KG MLCAPE/. STORMS
ARE EXPECTED TO REDEVELOP AND INTENSIFY ALONG PRE-FRONTAL OUTFLOW
BOUNDARIES...TERRAIN FEATURES AND WARM SECTOR AS THE ATMOSPHERE
DESTABILIZES. A BELT OF WLY DEEP LAYER FLOW WITH 40-50 KT MOSTLY
UNIDIRECTIONAL BULK SHEAR WILL ACCOMPANY THE UPPER TROUGH AND
CONTRIBUTE TO THE POTENTIAL FOR ORGANIZED STORMS INCLUDING
SUPERCELLS AND BOWING SEGMENTS. DAMAGING WIND WILL BE THE MAIN
THREAT...BUT ISOLATED HAIL WILL ALSO BE POSSIBLE ALONG WITH THE
THREAT FOR A COUPLE OF ISOLATED TORNADOES.
...ND THROUGH NWRN MN...
MODIFIED CP AIR WITH 50S DEWPOINTS WILL RESIDE IN VICINITY OF THE
DEEPER BAROCLINIC ZONE FROM THE NRN PLAINS INTO THE UPPER MS VALLEY.
SWLY LOW LEVEL WINDS INTERACTING WITH THIS BOUNDARY WILL MAINTAIN
ISENTROPIC LIFT IN THIS REGION...AND LIFT WILL LIKELY INCREASE
DURING THE EVENING AS THE LOW LEVEL JET STRENGTHENS. POTENTIAL WILL
EXIST FOR STORMS TO DEVELOP AND MOVE SEWD THROUGH ND INTO THE UPPER
MS VALLEY REGION. STORMS MAY INTENSIFY AS THE BOUNDARY LAYER
DESTABILIZES WITH SELY LOW LEVEL WINDS BENEATH 30-40 KT UPPER FLOW
RESULTING IN SUFFICIENT VERTICAL SHEAR FOR SUPERCELL STRUCTURES.
ISOLATED LARGE HAIL AND DAMAGING WIND WILL BE THE MAIN THREATS FROM
MID AFTERNOON THROUGH MID EVENING.
...CNTRL AND NRN HIGH PLAINS...
ATMOSPHERE WILL DESTABILIZE ACROSS THE CNTRL AND NRN HIGH PLAINS AS
DEVELOPING LEE TROUGH TRANSPORTS MODIFIED CP AIR NWD BENEATH STEEP
MID LEVEL LAPSE RATES. POTENTIAL WILL EXIST FOR STORMS TO DEVELOP
OVER THE HIGHER TERRAIN AND SPREAD EWD INTO THE HIGH PLAINS. DEEP
LAYER WINDS OVER THE NRN PLAINS WILL BE SUFFICIENT /40-50 KT BULK
SHEAR/ FOR SUPERCELLS FOR ANY STORMS THAT DEVELOP. WITH UPPER RIDGE
IN PLACE CONCERN IS THAT STORM COVERAGE COULD BE SOMEWHAT LIMITED.
...SERN STATES THROUGH SRN PLAINS...
A MOIST AND UNSTABLE WARM SECTOR WILL DEVELOP IN VICINITY OF FRONTAL
BOUNDARY FROM KY INTO THE TN VALLEY WWD INTO OK AND THE TX
PANHANDLE. HOWEVER...WARM SECTOR WILL HAVE BEEN SHUNTED SOUTH OF THE
STRONGER FLOW ALOFT. PULSE TO MULTICELL STORMS WILL LIKELY ONCE
AGAIN DEVELOP...AND THE THERMODYNAMIC ENVIRONMENT WILL SUPPORT A
THREAT OF ISOLATED DAMAGING WIND AND HAIL FROM AFTERNOON INTO THE
EARLY EVENING.
..DIAL/JEWELL.. 06/24/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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