Special Weather Statement, NWS North Platte, NE

Area Forecast Discussion
National Weather Service North Platte NE
613 PM CDT Fri Jul 28 2017

.SHORT TERM...(This evening through Saturday)
Issued at 243 PM CDT Fri Jul 28 2017

Latest satellite imagery and surface plot shows mostly cloudy
skies across much of western NEB and partly/mostly sunny skies
across north central NEB. Low-level clouds continue to affect
portions of the Panhandle and southwest NEB with ceilings MVFR to
low-end VFR (less than 7 kft). However, by and large cloud cover
continues to decrease gradually across west-east in the NEB
Panhandle. Surface dewpoints are elevated and range from the mid
and upper 60s in extreme southwest NEB to lower 60s elsewhere.
These dewpoints in the 60s should be preserved through the
afternoon-tonight time period. As such, they will support a
corridor of instability with daytime diabatic heating and the
decreasing cloud cover trend this afternoon and evening. A
corridor of moderate instability is expected over northeast CO
through the NEB Panhandle and far western NEB this afternoon with
MLCAPEs 1000-2000 J/kg that then tapers off over the Central
Sandhills and towards south central NEB.

Current thinking is isolated to scattered thunderstorms will
develop within an area occupying portions of northeast CO, NEB
Panhandle and Black Hills-southwest SD. Storms are expected to
track off eastward off the higher terrain into the eastern NEB
Panhandle and far western NEB late this afternoon and evening. Of
which, storms have developed already in the Black Hills area and
in the higher terrain near the Laramie Range as seen on the
regional radar display. Soundings show an environment
characterized by modest conditionally unstable lapse rates at
mid-levels (6-8 C/km) with decent vertical wind shear largely
30-45 kts. As such, multicells and some supercell structures
cannot be ruled out with respect to storm mode. Thus there is a
risk for isolated strong to severe thunderstorms this afternoon
and evening with large hail and strong winds the main hazard.
Locally heavy rainfall will be possible given high precipitable
water values and so-so storm motions around 10-20 kts. Precipitable
water values this afternoon and tonight will be about 125-150% of
normal in western NEB. Chances for showers/thunderstorms then
continue tonight into early tomorrow with thunder mention more so
isolated after midnight. Risk for isolated strong to severe
thunderstorms return tomorrow afternoon across much of western NEB
with decent instability in place again over a slightly larger
area in western NEB.

.LONG TERM...(Saturday night through Friday)
Issued at 243 PM CDT Fri Jul 28 2017

The main forecast challenge this forecast period is the chance of
precipitation over the weekend. The best chance for showers and
thunderstorms will come Saturday evening into Sunday with a
disturbance over the area.

For Saturday night through next Friday an upper level high
pressure system will sit across the western CONUS giving us an
upper level northwest flow. Under this longwave pattern conditions
will remain mostly dry. However, there will be a couple chances
for precipitation as a couple of shortwave troughs may move
through the area but confidence is low at this time.

High temperatures will remain near or slightly below normal for
the next week with temperatures in the 80s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 613 PM CDT Fri Jul 28 2017

There will be a chance for mainly isolated showers or
thunderstorms this evening and overnight, and also on Saturday.
Due to limited coverage, only VCSH mention at the KLBF terminal
from 06z-12z overnight, and from 00z-04z at KVTN. VFR conditions
area also forecast with lowest ceilings across western Nebraska
expected to remain above 7k feet overnight, lowering to 5k feet
Saturday morning.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.

&&

SHORT TERM...ET
LONG TERM...Gomez
AVIATION...Roberg

Hazardous Weather Outlook...UPDATED
National Weather Service North Platte NE
329 PM CDT Fri Jul 28 2017

NEZ004>010-022>029-035>038-056>059-069>071-094-292030-
Sheridan-Eastern Cherry-Keya Paha-Boyd-Brown-Rock-Holt-Garden-
Grant-Hooker-Thomas-Blaine-Loup-Garfield-Wheeler-Arthur-McPherson-
Logan-Custer-Deuel-Keith-Perkins-Lincoln-Chase-Hayes-Frontier-
Western Cherry-
329 PM CDT Fri Jul 28 2017 /229 PM MDT Fri Jul 28 2017/

This Hazardous Weather Outlook is for portions of western and
north central Nebraska.

.DAY ONE...TONIGHT.

There is a threat for isolated strong to severe thunderstorms
this afternoon and evening west of a line from Nenzel to Seneca
to North Platte to Wellfleet. Large hail and damaging winds are
the main hazards, as well as locally heavy rainfall.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

There is a threat for additional isolated strong to severe
thunderstorms Saturday afternoon through Saturday night along and
west of a line from Stockville to Anselmo to Bassett. Large hail
and damaging winds are the main hazards. Locally heavy rainfall
will be possible Saturday night also.

While thunderstorms are possible Sunday and beyond at times,
confidence and the overall threat for widespread severe
thunderstorms is low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.

&&

Get your weather, hydrological, and climate information at
http://www.weather.gov/northplatte

ET

Special Weather Statement
National Weather Service North Platte NE
930 PM CDT FRI JUL 28 2017

NEZ036-059-290315-
McPherson NE-Lincoln NE-
930 PM CDT FRI JUL 28 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL LINCOLN AND
SOUTHEASTERN MCPHERSON COUNTIES UNTIL 1015 PM CDT...

At 929 PM CDT, Doppler radar was tracking a strong thunderstorm 10
miles south of Ringgold, or 14 miles southeast of Tryon, moving south
at 15 mph.

Dime size hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
North Platte and Birdwood.

This includes the following highways...
 Highway 97 between mile markers 1 and 21.
 Highway 83 between mile markers 85 and 97.

LAT...LON 4143 10096 4147 10073 4144 10071 4139 10071
      4139 10068 4115 10055 4115 10095
TIME...MOT...LOC 0229Z 349DEG 14KT 4137 10083

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