Special Weather Statement, NWS North Platte, NE

Area Forecast Discussion
National Weather Service North Platte NE
256 PM CDT Sun Apr 4 2021

.SHORT TERM...(This evening through Monday night)
Issued at 254 PM CDT Sun Apr 4 2021

An upper level disturbance moving through Utah this afternoon will
emerge onto the central Plains of ern Colorado and KS this evening.
The disturbance, not readily discernable in the models but clearly
shown on Satellite might be the basis for isolated showers and
thunderstorms across swrn Nebraska this evening, but none of the
models suggest anything more than sprinkles-too dry, but it will be
close. The NAMnest, the most aggressive model, shows thunderstorms
taking off this evening across scntl Nebraska in response to a
strengthening low level jet. The forecast will lean on the NAM for
an isolated thunderstorm chance across a small portion of southwest
Nebraska.

The HREF, NAM and to a lesser extent the HRRR show another isolated
thunderstorm chance across ncntl Nebraska Monday evening. This storm
activity will form on the edge of a nearly stationary dryline. This
time, according to the NAM, winds aloft and instability might be
sufficient for strong or severe storm activity. CONRAD, courtesy of
Bufkit, suggests storm splitting in response to a belt of linear but
strong winds aloft. The NAMdng would suggest wind damage would be
the primary hazard with any storms which become severe and looking
at Bufkit, the very large T-Td spread below h500mb would certainly
support that claim. Note, the forecast for an isolated severe storms
is speculative for the following reasons: the upper level forcing is
weak and the sfc focus for storm development could be east of ncntl
Nebraska, across nern Nebraska.

The temperature forecast tonight, Monday and Monday night leans on
the short term model blend plus bias correction. This suggested
highs in the 80s Monday which is very close to the guidance blend
plus bias correction but several degrees cooler than the 50
percentile of the model blend which suggested highs around 90 in
many areas.

.LONG TERM...(Tuesday through Sunday)
Issued at 254 PM CDT Sun Apr 4 2021

There is not much change in the predicted track and evolution
of the storm system currently affecting British Columbia. The models
are in good agreement tracking the h700mb low through the Rockies
and Wyoming Monday. This low will move east into the Sandhills
Tuesday and then be drawn south into KS Tuesday night by heavy
convection.

There is a chance the system could drop south into nern Colorado and
then east into Kansas favoring more of wrn and ncntl Nebraska for
rain but this would be dependent on moisture transport into the
system. For now, the models are slow to moisten the system up and if
this holds true, the system would likely maintain the more easterly
track into the Sandhills as shown by the models.

The NAM continues show reasonable elevated CAPE of up to 1500J/KG
and this will easily support thunderstorms capable of small hail
Monday night and Tuesday. The 40kts of bulk shear and CAPE could
also support an isolated severe storm capable of large hail. These
storms would be most likely to occur across swrn and ncntl Nebraska
Monday night. All of these storms should be post frontal. A cold
front will sweep into wrn and ncntl Nebraska Monday evening. By
Tuesday afternoon, the upper low should be positioned over cntl KS
favor that area of severe weather.

The storm system will move slowly east Tuesday night and Wednesday.
Rain chances will be ending west to east during this time frame. The
models are in good agreement developing north and northeast winds of
20 to 25 mph as the storm departs wrn and ncntl Nebraska.

The departing storm Wednesday will end rain chances across wrn and
nctnl Nebraska for the rest of the week. Northwest flow aloft will
take hold Thursday and Friday. A second upper level low may drop
through the nrn Plains Friday presenting a rain chance Friday or
Saturday but the predictability of this occurring is very low. In
fact, the model blended forecast for this time frame is dry.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1229 PM CDT Sun Apr 4 2021

VFR conditions are expected to prevail for western and north central
Nebraska through tomorrow afternoon. Middle and high level clouds
continue to stream into western Nebraska this afternoon though no
aviation impacts are anticipated. Winds will transition from
southerly to westerly overnight, and largely remain below 15kts.

&&

.FIRE WEATHER...
Issued at 254 PM CDT Sun Apr 4 2021

Isolated thunderstorms capable of dry lightning have been observed
across southwest Nebraska this afternoon. This storm activity is
expected to continue into early evening affecting areas of
southwest and south central Nebraska along and south of a line
from Imperial to North Platte to Broken Bow.

A Pacific cold front moving through the WA-OR this afternoon should
move into nrn Nebraska Monday afternoon, perhaps 18z-21z. The
models are in fairly good agreement gusting winds to around 25 or
30 mph behind front but not ahead of it. Despite the cooler air
behind the front, a few hour period of gusty northwest winds and
RH near or below 15 percent should develop. A Fire Weather Watch
is in effect Monday afternoon and early evening across the
Sandhills, Niobrara region and eastern Nebraska Panhandle.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Monday afternoon through Monday evening
for NEZ204-206-208.

&&

SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Brown
FIRE WEATHER...CDC

Hazardous Weather Outlook
National Weather Service North Platte NE
253 PM CDT Sun Apr 4 2021

NEZ004>010-022>029-035>038-056>059-069>071-094-052000-
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-
253 PM CDT Sun Apr 4 2021 /153 PM MDT Sun Apr 4 2021/

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

Elevated to near critical fire weather conditions are expected
to continue this afternoon due to dry, warm, and breezy
conditions.

Isolated thunderstorms capable of dry lightning that could start
range fires have been observed across southwest Nebraska this
afternoon. This storm activity is expected to continue into early
evening affecting areas of southwest and south central Nebraska
along and south of a line from Imperial to North Platte to Broken
Bow.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

Very warm air and a cold front will produce gusty north winds
across the Sandhills, the Niobrara river valley and parts of the
Panhandle Monday afternoon. This weather may set the stage for
critical fire weather conditions. A Fire Weather Watch is in
effect for this reason.

Thunderstorms are possible on Monday evening through Tuesday
evening as the next storm system enters the region. A strong
thunderstorm or two cannot be ruled out on Monday afternoon and
evening across north central Nebraska. The greatest threats would
be damaging wind gusts and large hail in the strongest storms. Isolated
strong storms will be possible again Tuesday afternoon and
evening.

Precipitation may transition from rain to snow early Wednesday
morning as temperatures cool, generally west of Highway 61.
Measurable accumulations are not expected 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

Special Weather Statement
National Weather Service North Platte NE
445 PM CDT Sun Apr 4 2021

NEZ071-042230-
Frontier-
445 PM CDT Sun Apr 4 2021

...A STRONG THUNDERSTORM WILL AFFECT EASTERN FRONTIER COUNTY...

At 444 PM CDT, a strong thunderstorm was located near Medicine Creek
Reservoir State Recreation Area, or 20 miles northeast of McCook,
moving northeast at 25 mph.

Wind gusts up to 50 mph are possible with this storm.

Locations impacted include...
Medicine Creek Reservoir State Recreation Area, Orafino and Freedom.

LAT...LON 4037 10041 4066 10022 4059 9998 4044 9998
      4043 10009 4035 10010 4035 10039
TIME...MOT...LOC 2144Z 207DEG 20KT 4035 10029

Taylor