Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 010549
SWODY2
SPC AC 010548

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1248 AM CDT TUE SEP 01 2015

VALID 021200Z - 031200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
THUNDERSTORMS ARE EXPECTED TO DEVELOP WEDNESDAY FROM THE SOUTHWEST
STATES INTO THE CENTRAL ROCKIES AND CENTRAL HIGH PLAINS AS WELL AS
THE UPPER MISSISSIPPI VALLEY...GREAT LAKES...OHIO VALLEY AND THE
SOUTHEAST STATES. OTHER STORMS MAY OCCUR FROM THE PACIFIC NORTHWEST
INTO THE NORTHERN ROCKIES.

...SYNOPSIS...

LOW-AMPLITUDE UPPER PATTERN WILL PERSIST WEDNESDAY WITH A SYNOPTIC
TROUGH OVER THE NWRN U.S. ALONG WITH AN UPPER RIDGE FROM THE SRN
PLAINS INTO THE SERN STATES. A COUPLE OF LOW AMPLITUDE SHORTWAVE
TROUGHS WILL MOVE THROUGH THE UPPER MS VALLEY AND GREAT LAKES AS
WELL AS THE OH VALLEY AND MID-ATLANTIC REGION. A CUTOFF UPPER LOW
WILL REMAIN OVER THE NWRN GULF. AT THE SFC A LEE TROUGH WILL BECOME
ESTABLISHED OVER THE NRN AND CNTRL HIGH PLAINS...WHILE A COLD FRONT
ADVANCES SEWD INTO THE NRN HIGH PLAINS AND NRN ROCKIES.

...NRN PLAINS AND UPPER MS VALLEY REGION...

THE ATMOSPHERE SHOULD BECOME MODERATE TO STRONGLY UNSTABLE FROM THE
NRN PLAINS INTO THE UPPER MS VALLEY WHERE PLUME OF STEEP MID-LEVEL
LAPSE RATES WILL ADVECT EWD ABOVE AXIS OF RICHER BOUNDARY-LAYER
MOISTURE. THIS REGION WILL EXPERIENCE SIGNIFICANT HEIGHT RISES AS
UPSTREAM TROUGH AMPLIFIES. THUS POTENTIAL CAPPING ISSUES AND WEAK
FORCING SUGGEST THUNDERSTORM DEVELOPMENT WITHIN AXIS OF GREATER
INSTABILITY OVER THE NRN PLAINS WILL REMAIN LIMITED. THUNDERSTORMS
ARE MORE LIKELY EARLY IN PERIOD FROM PARTS OF THE UPPER MS VALLEY
INTO THE GREAT LAKES REGION IN ASSOCIATION WITH WARM ADVECTION AND A
WEAK VORTICITY MAXIMUM...BUT THIS ACTIVITY WILL REMAIN WITHIN A
WEAKLY SHEARED ENVIRONMENT AND SHIFT EWD AWAY FROM THE GREATER
INSTABILITY DURING THE DAY. OTHER STORMS MAY DEVELOP DURING THE
EVENING AND OVERNIGHT OVER A PORTION OF THE UPPER MS VALLEY REGION.
SOME OF THIS ACTIVITY COULD PRODUCE GUSTY SFC WINDS AND MARGINALLY
SEVERE HAIL.

...AZ AND NM...

HIGH BASED STORMS WILL ONCE AGAIN DEVELOP WITHIN THE MONSOONAL
CIRCULATION OVER THE SWRN STATES. A FEW DOWNBURST WINDS CANNOT BE
RULED OUT WITH THE STRONGER STORMS DURING THE AFTERNOON AND EVENING.

..DIAL.. 09/01/2015



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