[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 200557
SWODY1
SPC AC 200555

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1255 AM CDT THU JUL 20 2006

VALID 201200Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE MID MS
VALLEY...OH VALLEY THROUGH GREAT LAKES REGION...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL AND
NRN PLAINS...

...SYNOPSIS...

UPPER PATTERN WILL REMAIN DOMINATED BY STRONGER WLYS FROM THE NRN
ROCKIES THROUGH THE GREAT LAKES AREA. AN UPPER RIDGE WILL PERSIST
OVER THE SRN TWO THIRDS OF THE COUNTRY. EMBEDDED WITHIN THE STRONGER
WLYS AN UPPER TROUGH WILL CONTINUE EWD THROUGH SERN CANADA AND THE
GREAT LAKES. FARTHER W...THE SHORTWAVE TROUGH CURRENTLY MOVING INTO
THE NRN ROCKIES WILL BEGIN TO AMPLIFY SEWD INTO THE NRN HIGH PLAINS
BY THURSDAY EVENING AS IT CRESTS THE UPPER RIDGE. A COLD FRONT WILL
CONTINUE EWD THROUGH THE GREAT LAKES REGION IN ASSOCIATION WITH THE
NRN STREAM UPPER TROUGH. THIS BOUNDARY WILL EXTEND SWWD INTO THE
CNTRL PLAINS WHERE IT WILL BEGIN TO STALL. A SECONDARY FRONTAL SURGE
WILL ACCOMPANY THE SHORTWAVE TROUGH SEWD INTO THE NRN HIGH PLAINS BY
THURSDAY EVENING.


...MID MS VALLEY THROUGH THE OH VALLEY AND GREAT LAKES AREA...

STEEP LAPSE RATES HAVE SPREAD EWD FROM THE PLAINS ABOVE HIGHER
THETA-E AIR OVER THE MID MS VALLEY...RESULTING IN A RESERVOIR OF
STRONG INSTABILITY THAT WILL PERSIST INTO THURSDAY. MLCAPE IS
EXPECTED TO RANGE FROM 3500+ J/KG OVER PARTS OF THE MID MS VALLEY TO
AROUND 1500 J/KG OR LESS OVER THE OH VALLEY AND GREAT LAKES REGION
WHERE LAPSE RATES AND LOW LEVEL MOISTURE WILL BE MORE LIMITED.
COMPLICATING FACTOR FOR THIS OUTLOOK WILL BE POTENTIAL FOR ONGOING
STORMS EARLY IN THE PERIOD. ACTIVITY NOW OVER PARTS OF NERN IA AND
SRN WI MAY CONTINUE SEWD INTO N CNTRL IL BY THE START OF THE PERIOD.
 THE LOW LEVEL JET IS FORECAST TO WEAKEN DURING THE DAY WITH LARGELY
UNIDIRECTIONAL DEEP LAYER FLOW. AROUND 35-40 KT WLY 6 KM FLOW
ACCOMPANYING THE UPPER TROUGH WILL CONTRIBUTE TO DEEP LAYER SHEAR
SUFFICIENT FOR SOME ORGANIZED STORM STRUCTURES. HOWEVER...THE
STRONGER FLOW IS EXPECTED TO REMAIN N OF THE BETTER INSTABILITY.
CURRENT THINKING IS THAT ONGOING STORMS MAY RE-INTENSIFY AS THE
DOWNSTREAM ATMOSPHERE DESTABILIZES. OTHER STORMS MAY DEVELOP IN
ASSOCIATION WITH REMNANT OUTFLOW BOUNDARIES AND SPREAD EWD INTO THE
OH VALLEY. PRIMARY THREATS WILL BE DAMAGING WIND AND HAIL. OTHER
STORMS MAY DEVELOP FARTHER NE ALONG FRONT FROM THE GREAT LAKES INTO
SRN CANADA. THIS ACTIVITY MAY REACH PARTS OF THE NERN U.S. OVERNIGHT
WITH A THREAT OF ISOLATED DAMAGING WIND GUSTS.


....NRN HIGH PLAINS THROUGH CNTRL PLAINS...

ESELY UPSLOPE COMPONENT ALONG SRN PERIPHERY OF SURFACE RIDGE WILL
MAINTAIN BOUNDARY LAYER DEWPOINTS IN THE 50S OVER PARTS OF THE CNTRL
AND NRN HIGH PLAINS. STEEP LAPSE RATES ABOVE THIS MOIST AXIS WILL
CONTRIBUTE TO MODERATE INSTABILITY DURING THE AFTERNOON. STORMS WILL
LIKELY DEVELOP INITIALLY OVER THE HIGHER TERRAIN AND THEN SPREAD
SEWD INTO THE MOIST AXIS WHERE MODERATE INSTABILITY WILL EXIST. A
BELT OF STRONGER 40 KT MID LEVEL FLOW ACCOMPANYING THE UPPER TROUGH
WILL SPREAD SEWD ABOVE THE SELY LOW LEVEL FLOW CONTRIBUTING TO
SUFFICIENT SHEAR FOR SUPERCELLS. OTHER STORMS MAY DEVELOP N OF THE
SURFACE FRONT DURING THE EVENING AS THE LOW LEVEL JET STRENGTHENS
WITH STORMS EVENTUALLY EVOLVING INTO ONE OR MORE MCSS. LARGE HAIL
AND DAMAGING WIND WILL BE THE MAIN THREATS.

...SRN AZ...

ELY FLOW ON SRN PERIPHERY OF UPPER RIDGE SUGGESTS STORMS THAT
DEVELOP OVER THE RIM AND OVER THE HIGHER TERRAIN OF SERN AZ AND SWRN
NM WILL HAVE POTENTIAL TO SPREAD INTO THE DESERT VALLEYS.
TEMPERATURE/DEWPOINT SPREADS WILL BE SUFFICIENT FOR A THREAT OF
MICROBURSTS. HOWEVER...COVERAGE IS EXPECTED TO REMAIN TOO ISOLATED
FOR A SLIGHT RISK.

..DIAL/TAYLOR.. 07/20/2006