Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS48 KWNS 310902
SWOD48
SPC AC 310900

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0400 AM CDT FRI JUL 31 2015

VALID 031200Z - 081200Z

...DISCUSSION...
MODEL CONSENSUS IS THAT A BLOCKING PATTERN WILL PERSIST THROUGH THE
4-8 PERIOD CHARACTERIZED BY AN UPPER TROUGH OVER THE ERN STATES AND
A RIDGE THAT WILL SHIFT FROM THE ROCKIES INTO THE PLAINS.

DAY 4...SOME SEVERE THREAT WILL EXIST FROM A PORTION OF THE NERN
STATES INTO THE OH VALLEY ALONG AND AHEAD OF A SEWD-ADVANCING COLD
FRONT. AT THIS TIME THE STRONGER FORCING WILL REMAIN NORTH OF THE
AXIS OF STRONGER DESTABILIZATION WHICH WILL EXIST FROM THE UPPER
MIDWEST INTO THE OH VALLEY. THIS ALONG WITH POTENTIAL FOR EARLY
CONVECTION LOWERS CONFIDENCE IN WHERE TO PLACE A CATEGORICAL RISK
AREA AT THIS TIME...BUT AT LEAST A SLIGHT RISK MAY BE NEEDED IN
LATER OUTLOOKS.

DAY 5...MOISTURE WILL RETURN THROUGH THE CNTRL AND NRN PLAINS AS
TRAILING PORTION OF FRONT STALLS AND BEGINS ADVANCING NWD AS A WARM
FRONT CONTRIBUTING TO DESTABILIZATION. WHILE THIS REGION WILL LIE
BENEATH A LARGE-SCALE RIDGE...MODELS INDICATE A SHORTWAVE TROUGH
WILL SUPPRESS NWRN PERIPHERY OF THIS RIDGE...AND IT APPEARS FORCING
WILL BE SUFFICIENT TO INITIATE STORMS FROM THE HIGH PLAINS EWD INTO
THE CNTRL PLAINS IN VICINITY OF WARM FRONT. SOME OF THESE STORMS
WILL LIKELY BECOME SEVERE GIVEN AN EXPECTED FAVORABLE THERMODYNAMIC
ENVIRONMENT.

DAY 6-8...ORGANIZED SEVERE STORMS WILL BE POSSIBLE WITHIN THE NWLY
FLOW REGIME WHERE BELT OF STRONGER WINDS ALOFT OVERLAP A NW-SE
ORIENTED BOUNDARY. HOWEVER...WHERE THE GREATEST SEVERE POTENTIAL
WILL BE EACH DAY IS UNCERTAIN DUE TO IMPACTS OF PRIOR DAYS
CONVECTION.

..DIAL.. 07/31/2015


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