FXUS63 KOAX 180929

Area Forecast Discussion
National Weather Service Omaha/Valley NE
329 AM CST Fri Jan 18 2019

.SHORT TERM...(Today through Sunday)
Issued at 330 AM CST Fri Jan 18 2019

Will leave headlines as is, although snow amounts forecast with
this forecast cycle are a little lower for most of the area. WPC
and neighboring offices were involved in the collaboration for the
lower amounts. A winter weather system will affect the area
today into tonight, with cold temperatures still expected for
Saturday and Saturday night. It appears that temperatures will
moderate a bit Sunday, especially in our western counties.

Surface low pressure should track from western KS down toward the
OK/TX border by this evening, then toward southwest MO by
midnight. Cold air (-20 C or colder) was poised to the north in
Canada shown in the 00Z 850 mb analysis. 500 mb chart from last
evening showed an open wave with 12 hour height falls of 50-70
meters from eastern WA across UT and into western CO. There were a
couple of area of strong winds aloft, with the most significant
being a 130 knot jet streak punching southeast across CA.

For today and into this evening, two different areas of forcing
area expected to drive the heavier precipitation. Isentropic lift
has been occurring overnight, especially from around 280-295K.
Models suggest combination of best saturation and lift will keep
heaviest snow north of our area across SD/southern MN/northern IA
this morning and early afternoon. Some light snow will occur in
the northern parts of the forecast area this morning. For the
rest of the area, due to lack of ice aloft, we will probably see
freezing drizzle or a mix. This could lead to slick roads with
some ice accumulations, but less than a tenth of an inch. As
colder air moves in later today and ice is introduced aloft, we
should see a mix then changeover to mostly snow. Modest forcing
should lead to light snow across much of the area, with some
accumulations. Models suggest a second area of organized
precipitation will develop from northeast KS into northwest MO and
central IA. Heaviest precipitation is expected east and south of
our forecast area, but there is some chance (supported mostly by
the NAM model) that it could shift back northwest into southwest
IA and far southeast NE. Winds will also be gusty, potentially
creating some higher impacts. So for those reasons, will leave
the will winter storm warning in effect for now.

Precipitation should end by around midnight in much of the area,
especially along and north of Interstate 80. It may linger a bit
longer near the KS and MO borders. Then cold high pressure will
try to build south in from the north. This cold blast will be
somewhat short lived though, as winds turn to the south Saturday
night and then continue from the south for Sunday.

.LONG TERM...(Sunday night through Thursday)
Issued at 330 AM CST Fri Jan 18 2019

Pattern will be somewhat active in the long term period, with
precipitation chances Monday into Tuesday and then again toward
Friday. The precipitation type Monday could be light freezing
rain, with mainly light snow Monday night/Tuesday. This does not
look like a high impact event at this time, but will monitor and
adjust the forecast as we get closer. High temperatures next week
should be in the 20s and 30s. Monday will likely be the warmest
and Tuesday probably the coldest.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1130 PM CST Thu Jan 17 2019

MVFR conditions at KLNK/KOMA, becoming IFR through time with
deteriorating conditions. Expecting some freezing fog and
freezing drizzle to develop at both of these locations, around
09-12z at KLNK and 12-13z at KOMA. The freezing precipitation
should become snow by 15-18z, and then increase in intensity for
the afternoon as easterly winds become northeast. Areas of blowing
snow will eventually develop too through the afternoon and
evening. At KOFK, LIFR conditions early in the TAF period,
becoming IFR by 19z. Snow may develop at KOFK by 13z, and taper
off by 19/03z.


NE...Winter Weather Advisory from 6 AM this morning to 6 AM CST
Saturday for NEZ011-012-015>018-030>034-042>045-050>053-

IA...Winter Weather Advisory from 6 AM this morning to 6 AM CST
Saturday for IAZ043-055.

Winter Storm Warning from 9 AM this morning to 6 AM CST Saturday
for IAZ056-069-079-080-090-091.



LONG TERM...Miller
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