Day 4-8 Severe Weather Outlook Issued on May 13, 2013
Updated: Mon May 13 08:46:04 UTC 2013
Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
D6
132,717
6,531,195
Oklahoma City, OK...Omaha, NE...Wichita, KS...Lincoln, NE...Des Moines, IA...
D4
Thu, May 16, 2013 - Fri, May 17, 2013
D7
Sun, May 19, 2013 - Mon, May 20, 2013
D5
Fri, May 17, 2013 - Sat, May 18, 2013
D8
Mon, May 20, 2013 - Tue, May 21, 2013
D6
Sat, May 18, 2013 - Sun, May 19, 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 130844
SPC AC 130844
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0344 AM CDT MON MAY 13 2013
VALID 161200Z - 211200Z
...DISCUSSION...
FOCUS FOR WIDESPREAD SEVERE WEATHER REMAINS ACROSS THE CENTRAL
PORTION OF THE U.S. FOR LATE THIS WEEK /FRI. THROUGH SUN. MAY
17-19/...AS A WRN U.S. TROUGH PROGRESSES EWD INTO THE PLAINS.
THE GFS AND ECMWF CONTINUE TO DIFFER WITH RESPECT TO THE EJECTION OF
THIS FEATURE...WITH DIFFERENCES BETWEEN THE MODELS GRADUALLY
INCREASING WITH TIME. STILL...A CONSISTENT SIGNAL FOR CENTRAL U.S.
SEVERE WEATHER HAS BEEN HINTED AT FOR SEVERAL DAYS...WITH CURRENT
INDICATIONS THAT THE GREATEST THREAT MAY EXIST BEGINNING DAY 6 /SAT.
5-18/. WHILE THE GFS HINTS AT SOME POTENTIAL FOR DAY 5/FRIDAY --
PARTICULARLY ACROSS THE NRN PLAINS VICINITY...THE SLOWER ECMWF
MAINTAINS RIDGING ACROSS THE PLAINS DAY 5. THUS...FOCUS THIS
FORECAST WILL BE ON DAY 6...WITH THE ZONE OF OVERLAP OF THE TWO
MODEL SOLUTIONS EXISTING ACROSS THE CENTRAL PLAINS VICINITY. WITH
STRONG INSTABILITY EXPECTED AND SHEAR LIKELY SUPPORTIVE OF
SUPERCELLS...LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE...ALONG
WITH SOME TORNADO RISK.
ADDITIONAL SEVERE POTENTIAL WOULD LIKELY PERSIST -- THOUGH FARTHER E
-- FOR DAY 7/SUNDAY...BUT WITH DIFFERENCES IN MODEL SOLUTIONS
INCREASING AND WITH LIKELIHOOD FOR WIDESPREAD CONVECTION DAY 6
INFLUENCING DAY 7 CONVECTIVE POTENTIAL...WILL REFRAIN ATTM FROM ANY
AREAL ISSUANCE BEYOND DAY 6.
..GOSS.. 05/13/2013
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