Special Weather Statement, NWS North Platte, NE

Area Forecast Discussion
National Weather Service North Platte NE
714 PM CDT MON AUG 8 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 333 PM CDT Mon Aug 8 2016

A fairly moist and somewhat unstable atmosphere is in place across
the western high plains this afternoon. Expect widely scattered
thunderstorms to move east off the higher terrain into western
Nebraska this evening. Agree with SPC that there is a marginal risk
for a severe storm or two, as there is at least some shear present
along with 7 to 8 C/KM mid level lapse rates. See little support
though for storms to last much past sundown, and will only carry
pops through mid evening. Expecting stratus to develop again tonight
across southwest into central Nebraska, as moist southeast upslope
flow continues. Patchy fog also is possible.

Hot and humid conditions will return Tuesday as H850MB temperatures
increase as the upper level ridge builds overhead. As temperatures
rise with the increasing humidity /dew points 70F to 75F from North
Platte northeast through the Broken Bow and O'Neill areas/ heat
index readings near 100F are expected during the late afternoon
hours.

Shear decreases further Tuesday, and there is little support either
at the surface or aloft for thunderstorm activity and have went dry
all areas.

.LONG TERM...(Tuesday night through Monday)
Issued at 333 PM CDT Mon Aug 8 2016

Tuesday night through Thursday...bias corrected data continue to
suggest highs in the lower to mid 90s Wednesday. This a few degrees
below guidance. Bias correction also produces dew points in the 60s
to near 70 Wednesday which is slightly above guidance. A low level
jet around 30kt will operate Tuesday night and and the NAM12
suggests this would keep skies mostly clear. Patchy valley fog is
possible. The low level jet should keep the higher terrain well-
mixed and free of fog.

Thunderstorm chances Tuesday night revolve around shear and
instability across Wrn SD. It is more favorable north of Nebraska.
There will be a dryline bulge moving across Pine Ridge which could
spark an isolated storm.

The situation Wednesday and Wednesday night is a bit more precarious
with each model handling moisture and dynamics differently. The
NAM12 is the wettest solution and winds aloft are strong enough to
produce sufficient shear for thunderstorm segments and bows. Storm
motion would be east and northeast with the low level jet south-
southwest near 40 kt. Winds aloft are southwest and increase to 40
to 60 kt from 500 to 300 mb.

The ECM is faster producing thunderstorms during the day Wednesday
and nothing Wednesday night. The GFS is dry both Wednesday and
Wednesday night. There is no model consensus.

All in all...rainfall Tuesday night through Thursday would likely be
1/4 inch or less. If the NAM12 verifies...locally heavy rainfall
occurs with ambient precipitable water increasing to over 1.5 inches.

Cold air aloft takes hold Thursday and the NAM12 and ECM models
appear to be supporting thunderstorm chances across Ncntl Neb.
This storm activity would be post frontal and elevated vs sfc based
Wednesday. Bias correction produces highs in the 80s and this is
slightly cooler than the guidance.

Thursday night through Monday...a broad upper level trof forms
across the Cntl and Nrn plains. 700mb temperatures fall from 14C to
6C by Saturday and 500mb from -6C to -11C. This supports highs in
the lower 80s Friday and Saturday. Bias correction was close to the
guidance with this portion of the forecast. Cold air aloft could
support isolated to scattered thunderstorm coverage Thursday night
through Friday night.

The forecast is dry Saturday and beyond. A blend of Pacific and
Canadian high pressure moves in and dew points fall into the 50s to
near 60. Warm air will slowly return Sunday and Monday as heights
rise. Low pressure will reform on the Nrn High plains and draw warm
east off the Rockies. Highs rise into the mid and upper 80s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 714 PM CDT Mon Aug 8 2016

MVFR and local IFR ceilings should reform tonight mainly after 09z
as low level moisture remains in place across the region. IFR
expected once again from KOGA to KLBF and points southeast. Decent
mixing should erode the lower ceilings fairly quickly Tuesday
morning, with VFR all areas by midday.

&&

.LBF Watches/Warnings/Advisories...
None.

&&

SHORT TERM...Taylor
LONG TERM...CDC
AVIATION...Roberg

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
356 PM CDT MON AUG 8 2016

NEZ004>010-022>029-035>038-056>059-069>071-094-092100-
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-
356 PM CDT MON AUG 8 2016 /256 PM MDT MON AUG 8 2016/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN AND
NORTH CENTRAL NEBRASKA.

.DAY ONE...TONIGHT.

PATCHY FOG IS EXPECTED TO DEVELOP OVERNIGHT TONIGHT MAINLY SOUTH
OF A LINE FROM ONEILL TO HYANNIS.

A STRONG THUNDERSTORM OR TWO IS POSSIBLE THIS EVENING ACROSS FAR
WESTERN NEBRASKA AND THE PANHANDLE.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

HOT AND HUMID WEATHER IS EXPECTED TUESDAY AND WEDNESDAY...WITH
AFTERNOON HEAT INDEX VALUES NEARING 100 DEGREES ALONG AND EAST OF
HIGHWAY 83.

A FEW THUNDERSTORMS ARE POSSIBLE TUESDAY NIGHT THROUGH FRIDAY
NIGHT. AT THIS TIME THE THREAT FOR SEVERE STORMS IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.

&&

GET YOUR WEATHER...HYDROLOGICAL...AND CLIMATE INFORMATION AT
HTTP://WWW.WEATHER.GOV/NORTHPLATTE (ALL LOWERCASE)

TAYLOR

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORTH PLATTE NE
820 PM MDT MON AUG 8 2016

NEZ004-090300-
SHERIDAN NE-
820 PM MDT MON AUG 8 2016

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN SHERIDAN COUNTY
UNTIL 900 PM MDT...

AT 819 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
NEAR SLIM BUTTE...OR 13 MILES NORTHEAST OF CHADRON...MOVING
SOUTHEAST AT 20 MPH.

HALF INCH HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
WHITE CLAY...PINE RIDGE...
INTERSECTION OF HIGHWAY 87 AND LARABEE ROAD...
METCALF STATE WILDLIFE MANAGEMENT AREA AND INTERSECTION OF HIGHWAY
87 AND CRAVEN CREEK ROAD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 10 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 4300 10250 4273 10255 4283 10280 4300 10279
TIME...MOT...LOC 0219Z 307DEG 19KT 4296 10281

ROBERG