Damaging Winds in Nebraska, July 8 to 9, 2020

Area Forecast Discussion
National Weather Service Omaha/Valley NE
555 PM CDT Wed Jul 8 2020

...Updated Aviation Forecast Discussion...

.DISCUSSION...
Issued at 410 PM CDT Wed Jul 8 2020

SUMMARY: Summery. Generally hot and humid weather continues
through the forecast period. Expect occasional thunderstorm
chances with severe weather possible at times. This evening and
again late on Friday night pose the best chance for severe
thunderstorms.

TONIGHT: Still anticipating the development of a QLCS this
evening initiated as mid-level trough approaches the Missouri
River from the west. CAPE over 3000 J/Kg has developed over the
entire CWA, but as forecast, shear is anemic at about 20 kts max.
Model runs continue to delay the initiation and have now began to
trend further west with the strongest returns. While supercells
may kick off the event, expect outflow to dominate as storms
approach eastern Nebraska.

Wind gusts over 60 mph remain primary threat with some locally
heavy rain possible. Drought busting rain looks unlikely east of
the Missouri River. PWAT values are over 1.5", but heaviest rain
and best chance for severe winds likely west of and along a line
from Norfolk to Lincoln to Beatrice. A SEVERE WATCH is expected.

THURSDAY AND FRIDAY:

Have dropped POPs a bit and reduced chance of thunder for Thursday
as forcing and instability guidance continues to disappoint. The
later convection tonight will help quash the instability.
Maintaining 30-40 POPs and some general thunder but severe weather
looks unlikely.

Friday will push temperatures a couple of degrees higher as a
mid-level ridge pushes through. Expect highs near 90, but with
drier weather building in behind tonight's front, humidity will be
improved and apparent temps will not hit triple digits.

FRIDAY NIGHT:

Shortwave trough at mid-levels late Friday night. Another MCS may
develop northwest of here as a result on Friday. It may sweep
through northeast Nebraska and western Iowa after midnight
Friday... producing another threat of severe wind gusts.

WEEKEND AND BEYOND:

Expect dry conditions for the weekend as system ejects Saturday.
Overall pattern of trough in eastern CONUS and a ridge west of
here on the flip-side. Expect generally dry conditions with highs
within a few degrees of 90. Did bump highs up a couple of degrees
mid-week based on toasty 850 temps pushing 30-35C.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 551 PM CDT Wed Jul 8 2020

Thunderstorms are developing well west of TAF sites, but we are
forecasting more in eastern Nebraska later this evening.
Anticipate a line of storms with brief heavy rain to produce
powerful wind gusts as it works from NNW to SSE tonight. Will
impact KOFK between 04 and 06Z Thursday, between 06 and 08Z
Thursday for KLNK. Have left KOMA dry for now, but will monitor
trends.

Winds will turn from south to north with passage of the storm
system tonight.

&&

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

DISCUSSION...Nicolaisen
AVIATION...Nicolaisen

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
414 PM CDT Wed Jul 8 2020

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-091115-
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-
414 PM CDT Wed Jul 8 2020

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

.DAY ONE...Tonight and Thursday

Heat indices near 100 to 102 degrees have developed at some
locations this afternoon.

Thunderstorms are forecast later this evening, primarily over
portions of eastern Nebraska. While isolated occurrences of hail
or locally strong winds will be possible areawide, the highest
probability of severe weather occurrence will be west of a line
from Sioux City to Lincoln to Beatrice this evening. Damaging
winds will be the primary hazard. Hail to quarter size and locally
heavy rainfall are also possible.

.DAYS TWO THROUGH SEVEN...Thursday night through Wednesday

Another round of severe storms is possible late Friday
night/Saturday morning and evening over portions of eastern
Nebraska and southwest Iowa. Timing, location, and specific
hazards all remain uncertain at this point in time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will probably not be needed through tonight.

tsn

Special Weather Statement
National Weather Service Omaha/Valley Nebraska
859 PM CDT Wed Jul 8 2020

NEZ011-016-090245-
Knox NE-Antelope NE-
859 PM CDT Wed Jul 8 2020

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN ANTELOPE AND WESTERN
KNOX COUNTIES UNTIL 945 PM CDT...

At 858 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles east of Marty to 11 miles northwest of
Orchard to 5 miles southwest of Page. Movement was east at 40 mph.

Wind gusts up to around 50 mph will be possible with these storms.

Locations impacted include...
Neligh, Creighton, Verdigre, Clearwater, Orchard, Niobrara, Santee,
Brunswick, Center, Winnetoon, Royal, Verdel, Bazile Mills, Ashfall
Fossil Beds State Historical Park and The Highway 14 And 59 Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
northeastern Nebraska.

LAT...LON 4287 9825 4284 9819 4284 9815 4277 9806
      4277 9795 4282 9788 4286 9788 4287 9784
      4213 9784 4214 9830 4288 9830
TIME...MOT...LOC 0158Z 276DEG 34KT 4296 9831 4249 9835 4234 9848

MILLER