Day 4-8 Severe Weather Outlook Issued on Apr 20, 2016
Updated: Wed Apr 20 08:54:02 UTC 2016
Day 4 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 5 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 6 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 7 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
15 %
134,703
14,086,772
Dallas, TX...Fort Worth, TX...Oklahoma City, OK...Tulsa, OK...Arlington, TX...
Day 8 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4
Sat, Apr 23, 2016 - Sun, Apr 24, 2016
D7
Tue, Apr 26, 2016 - Wed, Apr 27, 2016
D5
Sun, Apr 24, 2016 - Mon, Apr 25, 2016
D8
Wed, Apr 27, 2016 - Thu, Apr 28, 2016
D6
Mon, Apr 25, 2016 - Tue, Apr 26, 2016
(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 15%, 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 unlikely (i.e., less than 15%) for the forecast day.
Forecast Discussion
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 200851
SPC AC 200851
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0351 AM CDT WED APR 20 2016
VALID 231200Z - 281200Z
...DISCUSSION...
THE MEDIUM RANGE MODELS BEGIN THE DAY 4 TO 8 PERIOD WITH AN
UPPER-LEVEL RIDGE OVER THE GREAT PLAINS AND MOVE THIS FEATURE EWD
INTO THE MS VALLEY ON SATURDAY/DAY 4 INTO SATURDAY NIGHT. ON
SUNDAY/DAY 5...THE ECMWF AND GFS MOVE AN UPPER-LEVEL TROUGH ACROSS
THE GREAT PLAINS AND RETURN MOISTURE NWD AHEAD OF THE SYSTEM. THE
MODELS SUGGEST THAT AN ISOLATED SEVERE THREAT COULD DEVELOP SUNDAY
AFTERNOON ACROSS PARTS OF THE SRN PLAINS BUT DIFFER ON THE AMOUNT OF
INSTABILITY THAT WILL BE IN PLACE. ON MONDAY/DAY 6...BOTH THE ECMWF
AND GFS CONTINUE TO INCREASE MOISTURE ACROSS THE SRN AND CNTRL
PLAINS WHERE A CORRIDOR OF MODERATE INSTABILITY COULD DEVELOP MONDAY
AFTERNOON. BOTH SOLUTIONS MOVE A SHORTWAVE RIDGE NEWD ACROSS THE SRN
AND CNTRL PLAINS MONDAY INTO MONDAY NIGHT AND SHOW AN UPPER-LEVEL
TROUGH APPROACHING THE SRN PLAINS ON TUESDAY/DAY 7. THE MODELS
SUGGEST A DRYLINE ORGANIZES ACROSS THE SRN PLAINS DURING THE DAY ON
TUESDAY WITH THUNDERSTORMS DEVELOPING ALONG AND EAST OF THE DRYLINE
LATE TUESDAY AFTERNOON. THE ECMWF SOLUTION ALSO SHOWS THE EXIT
REGION OF A MID-LEVEL JET OVERSPREADING THE SRN PLAINS ON TUESDAY.
THE MODELS ARE IN GENERAL AGREEMENT AND HAVE SHOWN ENOUGH RUN TO RUN
CONSISTENCY TO ADD A 15 PERCENT CONTOUR FOR PARTS OF CNTRL AND NORTH
TX...OK...SRN KS...NW AR AND FAR SW MO FOR TUESDAY AND TUESDAY
NIGHT. A SEVERE WEATHER EVENT WITH TORNADOES...LARGE HAIL AND WIND
DAMAGE WILL BE POSSIBLE. ON WEDNESDAY/DAY 8...THE MODEL SOLUTIONS
SHOW SOME VARIANCE WITH THE ECMWF EJECTING THE UPPER-LEVEL TROUGH
ENEWD ACROSS THE MS VALLEY WHILE THE GFS IS SLOWER KEEPING THE
INSTABILITY AXIS BACK OVER THE SRN PLAINS. ALTHOUGH A SEVERE THREAT
APPEARS PROBABLE TO DEVELOP ACROSS PARTS OF THE SCNTRL U.S. ON
WEDNESDAY...WILL GO PREDICTABILITY TOO LOW DUE TO MODEL DIFFERENCES.
..BROYLES.. 04/20/2016
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