Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 020547
SWODY2
SPC AC 020545

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1245 AM CDT WED SEP 02 2015

VALID 031200Z - 041200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
THUNDERSTORMS ARE EXPECTED THURSDAY FROM THE SOUTHWEST STATES INTO
THE CENTRAL ROCKIES AND CENTRAL HIGH PLAINS. OTHER STORMS MAY OCCUR
FROM THE GREAT LAKES REGION THROUGH THE OHIO VALLEY AND PARTS OF THE
AND NORTHEAST THROUGH SOUTHEAST STATES.

..SYNOPSIS...

A SYNOPTIC TROUGH WILL AMPLIFY OVER THE PACIFIC NW AND NRN ROCKIES
AREA WHILE A DOWNSTREAM RIDGE BUILDS OVER THE UPPER MS VALLEY AND
GREAT LAKES REGION. CUTOFF UPPER LOW WILL REMAIN OVER THE NRN GULF
AND SERN STATES. AT THE SFC A LEE TROUGH WILL PERSIST FROM THE NRN
THROUGH CNTRL HIGH PLAINS...WHILE A COLD FRONT MOVES SLOWLY SEWD
INTO THE NRN HIGH PLAINS AND NRN ROCKIES. A WEAK QUASI-STATIONARY
FRONT WILL PERSIST OVER THE UPPER MS VALLEY AND GREAT LAKES AREA.

...DESERT SOUTHWEST INTO THE CNTRL ROCKIES AND CNTRL HIGH PLAINS...

HIGH BASED STORMS WILL DEVELOP WITHIN SUBTROPICAL MOISTURE PLUME AND
IN ASSOCIATION WITH WEAK IMPULSES MOVING NEWD ALONG WRN PERIPHERY OF
UPPER RIDGE. A FEW INSTANCES OF DOWNBURST WINDS WILL BE POSSIBLE
WITH THIS ACTIVITY FROM LATE AFTERNOON THROUGH MID EVENING.

...NRN HIGH PLAINS...

SERIES OF WEAK IMPULSES WILL MOVE NEWD THROUGH THE NRN HIGH PLAINS
ALONG ERN PERIPHERY OF SYNOPTIC UPPER TROUGH...PRIMARILY IN POST
FRONTAL REGION. THE PRE-FRONTAL WARM SECTOR WILL BECOME STRONGLY
UNSTABLE...BUT A WARM EML WILL HAVE OVERSPREAD THE MOIST WARM SECTOR
RESULTING IN A CAP. WHILE IT IS POSSIBLE A STORM OR TWO COULD
DEVELOP ALONG THE COLD FRONT OR PRE-FRONTAL TROUGH...THE STRONGER
FORCING WILL REMAIN NORTH AND WEST OF THE WARM SECTOR WITH LOW
CONFIDENCE IN THUNDERSTORM INITIATION EXCEPT IN POST FRONTAL REGIME.
SHOULD STORMS DEVELOP ALONG OR AHEAD OF THE FRONT...THEY WOULD POSE
A THREAT FOR DOWNBURST WINDS AND HAIL.

...GREAT LAKES REGION THROUGH THE OH VALLEY...

THUNDERSTORMS MAY BE ONGOING EARLY THURSDAY OVER THE GREAT LAKES.
CONVECTIVELY-AUGMENTED VORTICITY MAXIMA EMBEDDED WITHIN WEAK NWLY
FLOW REGIME ALONG WITH BOUNDARY LAYER DESTABILIZATION WILL SUPPORT
RENEWED DEVELOPMENT OF WIDELY SCATTERED THUNDERSTORMS FROM THE GREAT
LAKES INTO THE OH VALLEY. THIS ENVIRONMENT WILL BE CHARACTERIZED BY
MODERATE INSTABILITY...WEAK MID-LEVEL LAPSE RATES AND WEAK VERTICAL
SHEAR. WHILE A FEW STRONG WIND GUSTS MAY ACCOMPANY SOME OF THE
STORMS...OVERALL SEVERE THREAT APPEARS LIMITED.

..DIAL.. 09/02/2015




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