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fxus63 koax 280849 
afdoax

Area forecast discussion
National Weather Service Omaha/valley NE
249 am CST Tue Feb 28 2017

Short term...(today through thursday)
issued at 243 am CST Tue Feb 28 2017

Warm and moist air advection at low to mid levels is bringing
increasing clouds and keeping temperatures mild. Subjective 00z
upper-air analysis indicates a broad upper-level trough in the
western US, with west-southwesterly flow across the central US.
500mb heights generally were neutral to rising everywhere except in
WA/BC. A potent 150kt upper-level jet streak was noted across UT-co.
An 850mb low was centered in western NE/northeast co, with 0c+
dewpoints as far north as koma in the warm sector ahead of it,
though baroclinic zones/fronts remain poorly defined. At 08z, a
1000mb surface low was centered in south central NE, with surface
warm front extending eastward roughly across the I-80 corridor into
Iowa.

Main forecast concern is precipitation potential today through
tonight. Fog has not really materialized in most of the area, with
only a site or two in central NE reporting restricted visibilities
at this hour. Have kept the mention before 12z, but think it
overall won't be a mentionable threat for today. Surface low will
continue to slide across eastern NE this morning, with baroclinic
zones sharpening from surface to mid- levels. Temperatures likely
will reach morning (northwest) to midday (central) to early
afternoon (southeast) highs before falling behind the cold
front/inverted trough. A Post-frontal band of precipitation
should develop in the afternoon from central NE to northwest IA,
and have increased pops this afternoon. Despite falling
temperatures, I do think precipitation will remain all rain in the
afternoon. A second band of precipitation looks likely to develop
from northeast Kansas through southeast NE and northwest MO into
southwest Iowa during the evening. As temperatures continue to fall,
along with some dynamical cooling, this precipitation may mix
with or briefly change to snow before it ends. Have continued to
keep essentially nil accumulations (0.1 in a few patchy areas) as
precipitation has trended toward ending before the vertical
thermodynamic profile really GOES to truly favoring snow.

In wake of the cold front and as the upper-level trough moves into
the Great Lakes, temperatures will temper down toward normal for
Wednesday. Temperatures should be a touch cooler yet on Thursday at
least in the northeastern half of the County Warning Area as a reinforcing cold air
shot pushes toward the Missouri River valley, though readings may
nudge up a degree or two in the southern to southwestern County Warning Area as
baroclinicity sharpens overall.

Long term...(thursday night through monday)
issued at 243 am CST Tue Feb 28 2017

As the Great Lakes trough moves away and upper-level ridging reaches
toward the central US, 500mb heights should rise Thursday night and
Friday. Surface winds will turn southerly and mid-level winds
southwesterly, bringing moderating temperatures on Friday and well
above-normal temperatures for the weekend. Temperatures on both
Saturday and Sunday should easily reach the 60s and possibly 70s as
850mb temperatures reach the teens under favorable mixing
conditions.

An upper-level shortwave has been progged consistently to move
across the Dakotas to upper Midwest on Sunday night/Monday, dragging
a cold front through the Central Plains. The frontal passage looks
to remain dry for our area, with the 500mb low deepening and the
surface front encountering better moisture to our east. Temperatures
will cool down behind the front, but the airmass is not exactly
Arctic behind it, and temperatures are likely to merely return to
just being somewhat above normal instead of substantially above
normal.

&&

Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 1128 PM CST Mon Feb 27 2017

Area of MVFR cigs will spread north ahead of a low pressure system
and into eastern Nebraska between 06z and 12z. A cold front will
quickly follow, with more MVFR cigs just behind the front between
12z and 18z. All eastern taf sites could see MVFR cigs, but koma
is most likely to have cigs drop below fl020 through 18z. Low
level moisture will also increase, leading to areas of MVFR fog,
with some IFR vsbys likely at koma between 12z and 15z. There is a
chance for rain or a mix of rain and snow to develop near klnk and
koma after 21z, which could lead to IFR vsbys again. However the
most likely area of development will be southeast of these taf
sites.



&&

Oax watches/warnings/advisories...
NE...none.
Iowa...none.
&&

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