Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 180921

Area Forecast Discussion
National Weather Service North Platte NE
421 AM CDT Tue Jul 18 2017

.SHORT TERM...(Today and tonight)
Issued at 321 AM CDT Tue Jul 18 2017

Weather highlights the next 24 hours include: lingering showers and
thunderstorms through the small hours, another round of
thunderstorms this afternoon-tonight, and hot and humid conditions
across the extreme south and southeast. Latest radar display shows
largely disorganized convection with showers and thunderstorms over
portions of central NEB and northern NEB. Latest water vapor imagery
shows a shortwave trough over eastern NEB tracking east into the
Middle-Lower Missouri Valley this morning. Elsewhere, quasi-zonal
mid-level flow is present across the Pacific Northwest to Northern
Plains with high pressure stretching across the Four Corners-
Southern Plains.

Forecast on track for the heat advisory that goes into effect this
afternoon-early evening -- this is in effect for the southernmost
counties in the local forecast area and Custer county. The latter
was added this package and this could be attributable to higher
humidity with dew points expected to approach/reach 70 degrees this
afternoon. Heat index values between 100-105 degrees are expected in
these counties.

Current thinking is the ongoing convection will wane and taper off
early this morning. Thereafter, attention turns to this afternoon
and onward with respect to thunderstorm chances. A weak cold front
will advance southward later today, however, there is some questions
with respect to its timing and far it will advance. Current thinking
is it will roughly bisect the local forecast area southwest to
northeast by late this afternoon. Increased chances are then
expected. Thunderstorm chances increase roughly along this
orientation with storms that may develop along/vicinity of the
front. Otherwise, thinking storms may also develop and move off the
higher terrain in northeast CO and the southern Panhandle eastward
over parts of southwest NEB late this afternoon-evening. There is a
modest signal for this evolution in the SPC SSEO in the
spaghetti/paintball and neighborhood probs plots. With respect to
storm mode, current thinking is organized multicells and clusters
given soundings and deep layer vertical wind shear. As such,
isolated strong to briefly severe thunderstorms will be possible.

.LONG TERM...(Wednesday through Monday)
Issued at 321 AM CDT Tue Jul 18 2017

Hot and somewhat humid weather will persist Wednesday and
Thursday as an upper level ridge of high pressure remains anchored
across the southern plains. May have to extend the heat advisory
to cover those days as heat index readings at or slightly over 100
degrees appears likely across central into southwest Nebraska.
Then a slight pattern change as the upper ridge flattens somewhat
and a shortwave disturbance moving across southern Canada drives
a cold front south into the region. This will bring more seasonal
temperatures with highs in the lower 90s Saturday and mid to upper
80s for the weekend into early next week.

Rain chances are there but storms will remain relatively isolated
through the period. Slightly higher chances for rain will come
Saturday through Sunday night as upslope flow develops north of
the stalled cold front located to our south. Will keep rain
chances at 30 percent or lower due to the rather unorganized
nature of the any storm activity.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1135 PM CDT Mon Jul 17 2017

Little confidence exists in the forecast over the next 6 to 12
hours as the short range solutions including the HRRR, 4KM/NAM12
and operational NAM12 have done a bad job depicting the storms
over northern Nebraska tonight. Based on the trajectory of ongoing
convection in northwestern Cherry county, will utilize a tempo
group for the KVTN terminal from 06z to 10z overnight. Realize
this may need to be adjusted as the convection approaches the
area. As storms approach, there is the potential for wind gusts to
40 MPH with heavy rain and small hail possible. After 10z,
scattered to broken cigs around 15000 FT AGL are expected. For the
KLBF terminal, am expecting dry conds attm with no threat for
thunderstorms overnight into Tuesday morning. There is a small
threat for thunderstorms tomorrow afternoon, but coverage will be
limited and will forgo mentioning them in the 06z TAF.


Heat Advisory from 1 PM CDT /noon MDT/ this afternoon to 8 PM
CDT /7 PM MDT/ this evening for NEZ038-069>071.



LONG TERM...Taylor
AVIATION...Buttler is the U.S. government's official web portal to all federal, state and local government web resources and services.