Scientific Forecaster Discussion
fxus63 koax 182327
Area forecast discussion
National Weather Service Omaha/valley NE
627 PM CDT Fri Oct 18 2019
..updated aviation forecast discussion...
issued at 255 PM CDT Fri Oct 18 2019
Tonight through Saturday night:
A low-amplitude shortwave trough spanning the U.S. Rockies this
afternoon will move through the Great Plains tonight and Saturday
morning in tandem with a surface cold front. Despite strong south
winds ahead of the front, low-level moisture return is meager
beneath a warm elevated-mixed layer, per 12z regional soundings.
As a result, considerable forcing for ascent will be required for
convective inhibition to be overcome with showers and thunderstorm
chances increasing after about 10 PM. Any convective development
should move east of the area by mid morning on Saturday with
temperatures warming into the mid to upper 60s by afternoon.
Sunday through Monday night:
An intense shortwave trough will progress from The Rockies and
subsequently form a deep-layer cyclone over South Dakota and NE by Sunday
evening. That system will advance into the upper MS valley on
Monday. Gusty south winds will develop ahead of the associated
cold front on Sunday with the resultant enhancement of poleward
moisture flux likely yielding an increase in clouds. That will
limit daytime heating (i.E. Highs in the 60s) as well as inhibit
the destabilization progress, and by extension, mitigate any more
robust severe-weather threat. Nonetheless, it still appears that
a forced band of showers and a few thunderstorms will materialize
along the cold front over eastern NE Sunday afternoon and evening
with activity rapidly spreading east through the remainder of our
area Sunday night.
Monday will be windy and cooler. Northwest winds could gust to
40-50+ mph, and another Wind Advisory appears likely. Temperatures
will be mainly in the 50s with widely scattered showers,
especially across the northern half of the area. The showers could
linger into Monday night.
Tuesday and wednesday:
Temperatures will gradually moderate (i.E. Highs in the 50s and
60s) ahead of the next upper-air system developing over the
northern rockies. The weather should be dry.
Wednesday night into friday:
The northern rockies shortwave trough is forecast to amplify over
the mid MO valley on Thursday while an associated cold front moves
through the region. The arrival of those features will support an
increasing chance of showers Wednesday night into Thursday, most
of which would fall as rain. There is some potential that the
rain could mix with light snow Thursday morning over northeast
NE. Dry weather returns to the forecast on Friday.
Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 622 PM CDT Fri Oct 18 2019
VFR conditions will continue through the period. Wind speeds will
continue to diminish this evening, and veer to the northwest as a
cold front continues to progress through the region. A few
showers will be possible at klnk and koma between 05-11z
tonight/Saturday morning. A stray thunderstorm could reach klnk,
with the best chance between 05-07z. Otherwise light northwesterly
winds and VFR conditions will continue through Saturday.