Day 4-8 Severe Weather Outlook Issued on May 17, 2013
Updated: Fri May 17 08:59:04 UTC 2013
Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
D4
96,291
8,355,020
Oklahoma City, OK...Kansas City, MO...Tulsa, OK...Wichita, KS...Overland Park, KS...
D4
Mon, May 20, 2013 - Tue, May 21, 2013
D7
Thu, May 23, 2013 - Fri, May 24, 2013
D5
Tue, May 21, 2013 - Wed, May 22, 2013
D8
Fri, May 24, 2013 - Sat, May 25, 2013
D6
Wed, May 22, 2013 - Thu, May 23, 2013
(All days are valid from 12 UTC - 12 UTC the following day)
Note: A severe weather area depicted in the Day 4-8 period indicates a 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears highly unlikely during the entire period (e.g. less than a 30% probability for a regional severe storm area across the CONUS through the entire Day 4-8 period).
Forecast Discussion
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 170857
SPC AC 170857
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0357 AM CDT FRI MAY 17 2013
VALID 201200Z - 251200Z
...DISCUSSION...
THE MEDIUM RANGE MODELS BEGIN THE DAY 4 TO 8 PERIOD WITH AN
UPPER-LEVEL LOW OVER THE NRN PLAINS. THE MODELS DEEPEN THE
UPPER-LEVEL LOW AND MOVE A MID-LEVEL JET ACROSS THE SRN AND CNTRL
PLAINS ON MONDAY/DAY 4. IN RESPONSE...STRONG DEEP LAYER SHEAR SHOULD
BE PRESENT ACROSS MUCH OF THE WARM SECTOR SUGGESTING WIDESPREAD
SEVERE STORM DEVELOPMENT WILL BE POSSIBLE. WILL MAINTAIN AN ENHANCED
SEVERE THREAT AREA EXTENDING FROM CNTRL OK NEWD INTO NCNTRL MO FOR
DAY 4. ON TUESDAY/DAY 5...THE MODELS DIVERGE CONCERNING THE
UPPER-LEVEL LOW BUT ARE IN AGREEMENT THAT AN UPPER-LEVEL TROUGH WILL
MOVE ACROSS THE SRN AND CNTRL PLAINS. THUNDERSTORM DEVELOPMENT WILL
BE POSSIBLE AHEAD OF THE UPPER-LEVEL TROUGH FROM THE MID MS VALLEY
SWWD INTO THE SRN PLAINS ON DAY 5. A CHANCE OF SEVERE STORMS WILL
PROBABLY EXIST ALONG THIS CORRIDOR DUE TO MODERATE INSTABILITY AND
SUFFICIENT DEEP LAYER SHEAR WHICH IS FORECAST BY BOTH THE ECMWF AND
GFS. ON WEDNESDAY/DAY 6...THE MODELS MOVE THE SRN PLAINS UPPER-LEVEL
TROUGH QUICKLY EWD ACROSS THE MS VALLEY. ALTHOUGH THE GFS AND ECMWF
DIFFER ON THE SPEED OF THE UPPER-LEVEL TROUGH...IT APPEARS THAT A
POTENTIAL FOR SEVERE THUNDERSTORMS WILL EXIST ACROSS AN EXTENSIVE
AREA STRETCHING FROM THE NERN U.S. SWWD TO THE GULF COAST STATES AND
WWD INTO THE SRN PLAINS. EVEN THOUGH THERE IS POTENTIAL FOR A
WIDESPREAD SEVERE WEATHER FOR BOTH TUESDAY AND
WEDNESDAY...CONFIDENCE REMAINS TOO LOW TO FORECAST AN ENHANCED
SEVERE THREAT AREA.
..BROYLES.. 05/17/2013
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