Tornado and Damaging Winds in Nebraska, June 1, 2018

Area Forecast Discussion
National Weather Service Omaha/Valley NE
644 AM CDT Fri Jun 1 2018

.SHORT TERM...(Today through Sunday)
Issued at 305 AM CDT Fri Jun 1 2018

Another hot day is in store with upper level ridging in place
ahead of the next strong trough moving through the northern
Rockies. Highs today should again reach the mid 90s, which would
tie or set new records at Lincoln and Omaha, but probably not hot
enough at Norfolk. Otherwise, mostly sunny skies today with breezy
south southeast winds developing at 15 to 20 mph.

Focus shifts to developing convection across central SD southward
into central NE by 21-23z along or just ahead of the surface
trough, but remaining west of our forecast area before 6 pm. The
GFS and Canadian hint at development in southeast NE during the
late afternoon, but feel the cap will hold in that area and will
keep storms out until later in the evening.

Wind shear is sufficient for supercellular storms when they
develop with all modes of severe weather possible, which could
impact northeast NE early in the evening. These storms will likely
congeal into a severe MCS that spread east southeast through the
evening across eastern NE with primarily a significant threat for
damaging winds, but there also appears to be a hail threat as
updraft helicity seem to ramp up by late evening across the
southern portion of the forecast area as depicted by the HREF
data. SPC has placed most of eastern NE in an enhanced risk of
severe storms tonight, which seems reasonable. Storms likely
develop into our northeast NE counties by 7-8 pm, then develop
east southeast through the evening hours. Severe storm threat
continues well after midnight, with a severe threat perhaps until
2-4 am, and even lingering thunderstorms through daybreak
Saturday.

PW values eventually increase to 1.25 to 1.5 inches, which is
about 1 standard deviation above normal. Thus there will be the
possibility of locally heavy rainfall overnight, especially for
areas that would see training developing by late evening and
overnight. Basin average forecast rainfall amounts range from 0.50
to 1.5 inches, but this may be on the low side across portions of
southeast NE could see a couple of rounds of storms. WPC has
placed some of the area in a slight risk of excessive rainfall,
but widespread flash flooding is not expected.

Showers and storms wind down Saturday morning, with significantly
cooler temps and breezy northwesterly winds. Highs saturday in the
upper 70s to lower 80s, more seasonable readings.

Dry weather for Sunday with temps in the lower 80s.

.LONG TERM...(Sunday night through Thursday)
Issued at 305 AM CDT Fri Jun 1 2018

Another weak weather system moving out of the Rockies could bring
a small chance of showers and storms Monday into Monday night. The
ECMWF is a little more progressive with this wave, but the GFS is
just a bit slower. Tuesday should be dry with short wave ridging
in place across the region with highs back into the upper 80s.
Wednesday sees high back around 90, but with a slight chance of
showers/storms as models hint at another weak wave moving through
the mean ridge that remains in place across the area. Highs
Thursday again around 90.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 636 AM CDT Fri Jun 1 2018

VFR conditions and increasing south winds are expected through the
day today. Strong to severe storms will develop and impact TAF
sites this evening and have tried to focus the TAFs on most likely
hours for these storms to impact each location. While not
currently reflected in the TAF, any storms impacting TAF sites
this evening and overnight may produce very strong winds 60 mph to
80 mph and damaging hail.

&&

.CLIMATE...
Issued at 305 AM CDT Fri Jun 1 2018

Another very hot day is expected with highs in the lower to mid
90s. Based on the current forecast, record temperatures could be
tied or broken at Lincoln and Omaha.

Omaha: 95/1934     Lincoln: 96/1934     Norfolk: 98/1955

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

SHORT TERM...DeWald
LONG TERM...DeWald
AVIATION...Barjenbruch
CLIMATE...DeWald

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
517 AM CDT Fri Jun 1 2018

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-020030-
Monona-Harrison-Shelby-Pottawattamie-Mills-Montgomery-Fremont-
Page-Knox-Cedar-Thurston-Antelope-Pierce-Wayne-Boone-Madison-
Stanton-Cuming-Burt-Platte-Colfax-Dodge-Washington-Butler-
Saunders-Douglas-Sarpy-Seward-Lancaster-Cass-Otoe-Saline-
Jefferson-Gage-Johnson-Nemaha-Pawnee-Richardson-
517 AM CDT Fri Jun 1 2018

This Hazardous Weather Outlook is for portions of southwest
Iowa...west central Iowa...east central Nebraska...northeast
Nebraska and southeast Nebraska.

.DAY ONE...Today and Tonight

High temperatures will reach the mid 90s this afternoon. This
could tie or break records at both Lincoln and Omaha today.

Severe storms are expected to develop across central Nebraska by
mid afternoon, and would move into northeast Nebraska by 7 to 8
pm, then spread east southeast through the remainder of the
evening. Supercell storms will be possible in northeast Nebraska,
with damaging winds, large hail, and a tornado or two possible.
Elsewhere, strong damaging winds 70 mph or higher would be the
main hazard tonight, but also hail up to 2 inches in diameter.
Locally heavy rainfall up to 2 could also occur, and training of
thunderstorms could develop, with 2 or 3 rounds of strong to
severe storms in the same locations, which could result in a
small flash flood risk for some areas. Most of eastern Nebraska
is an an enhanced risk of severe storms for this evening and
tonight. The severe weather threat will linger for several hours
past midnight, until 2 to 4 am Saturday morning.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Isolated non severe thunderstorms could still occur Saturday
morning. Additional thunderstorm chances will exist Monday and
Wednesday of next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed tonight.

DeWald