Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS48 KWNS 050856
SWOD48
SPC AC 050855

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0355 AM CDT WED AUG 05 2015

VALID 081200Z - 131200Z

...DISCUSSION...
GIVEN FORECAST UNCERTAINTY DESCRIBED IN THE D3 OUTLOOK VALID FOR
FRIDAY...IT SEEMS REASONABLE TO EXPECT CONTINUED UNCERTAINTY INTO
THE EXTENDED RANGE. HOWEVER...LATEST GLOBAL MODELS AND THE GFS
ENSEMBLE DO SEEM TO BE IN GENERALLY GOOD AGREEMENT ABOUT AT LEAST
ONE ASPECT OF THE LARGE SCALE PATTERN ACROSS THE CONUS INTO NEXT
WEEK. THE AMPLITUDE OF THE MIDLEVEL FLOW IS FORECAST TO INCREASE AS
SUBTROPICAL RIDGE STRENGTHENS ACROSS THE MIDDLE OF THE CONUS AND
EXPANDS NWD INTO CENTRAL CANADA. AS THIS PROCESS UNFOLDS /IF IT
UNFOLDS/ UPPER TROUGHS ON BOTH COASTS WILL LIKEWISE AMPLIFY/DEEPEN.
IN ADDITION...THIS PATTERN EVOLUTION...OCCURRING AROUND THIS TIME OF
YEAR...TENDS TO SUPPORT EPISODIC MCS DEVELOPMENT ACROSS THE PLAINS
AND MIDWEST...ON THE NRN/NERN FLANK OF THE RIDGE WHERE SHEAR AND
INSTABILITY TEND TO SUPPORT ORGANIZED STORMS WHEN CAPPING CAN BE
OVERCOME THROUGH DIABATIC AND SYNOPTIC INFLUENCES.

D5/SUN SEEMS TO BE THE FIRST IN A SEQUENCE OF DAYS WHEN CONDITIONS
MAY COME TOGETHER TO SUPPORT ORGANIZED SEVERE STORMS ACROSS THE
MIDWEST/CORN-BELT. HOWEVER...TIMING AND STRENGTH DIFFERENCES IN THE
LOW-AMPLITUDE SHORTWAVE TROUGH THAT WILL AID DEVELOPMENT OVER THE
REGION ARE SUCH THAT CONFIDENCE IN DELINEATING A RISK AREA IS LOW.
DISCREPANCIES IN THE MINOR DETAILS THAT MATTER FOR SEVERE WEATHER
FORECASTING ONLY INCREASE IN THE EXTENDED PERIOD AND PREDICTABILITY
REMAINS TOO LOW FOR ANY OTHER DAILY OUTLOOK AREAS AT THIS TIME.

..CARBIN.. 08/05/2015


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