Day 4-8 Severe Weather Outlook Issued on Apr 12, 2018
Updated: Thu Apr 12 08:38:02 UTC 2018
Day 4 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
15 %
177,226
34,513,433
Jacksonville, FL...Charlotte, NC...Virginia Beach, VA...Miami, FL...Raleigh, NC...
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
No Risk Areas Forecast
Day 8 Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4
Sun, Apr 15, 2018 - Mon, Apr 16, 2018
D7
Wed, Apr 18, 2018 - Thu, Apr 19, 2018
D5
Mon, Apr 16, 2018 - Tue, Apr 17, 2018
D8
Thu, Apr 19, 2018 - Fri, Apr 20, 2018
D6
Tue, Apr 17, 2018 - Wed, Apr 18, 2018
(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 120836
SPC AC 120836
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0336 AM CDT Thu Apr 12 2018
Valid 151200Z - 201200Z
...DISCUSSION...
Latest runs of the medium-range models are exhibiting fairly
considerable differences from one another with eastward progression
of an eastern U.S. cold front Day 4/Sunday. The differences in
handling of synoptic features become even more pronounced beyond, as
the next Pacific trough enters/crosses the U.S. in the Day 5-8 time
frame.
Despite the Day 4 variability in the models, it is apparent that an
ongoing line/band of storms will progress steadily eastward across
the Appalachians early in the day, and then continue east across the
Atlantic Coast states. While warm-sector instability remains a
substantial uncertainty -- in part due to variability in the speed
of the frontal advance toward the coast -- the kinematic environment
will support organized convection. As such, will introduce a 15%
area extending from parts of Virginia south to Florida, with
damaging wind likely to be the predominant severe risk until frontal
convection moves offshore.
Given the aforementioned/increasing differences amongst model
solutions Day 5 and beyond, no assessment of severe risk can be
offered at this time.
..Goss.. 04/12/2018
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