Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 281714
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1114 AM CST Mon Nov 28 2016

.SHORT TERM...(today through Wednesday)
Issued at 331 AM CST Mon Nov 28 2016

Colder temperatures and slight chances for light precipitation are
the primary highlights of the forecast through mid week.

Upper low had moved into South Dakota as expected this morning, with
a vorticity center rotating northeast around the low across eastern
South Dakota into southwest Minnesota. This feature shows up nicely
on radar loops, and shows precipitation lifting well north of our
area this morning. We were still seeing relatively mild temperatures
this morning, mainly in the 40s, as gusty south to west winds
covered much of the Plains. Coldest air was still north and west of
upper low, and will gradually ooze south into our area with time
this week.

Models are in much better agreement this morning in regards to
movement and eventual departure of upper low in/through the Northern
Plains. Low center is forecast to lift north into North Dakota
today, then rotate south and southeast toward northwest Iowa late
Tuesday before lifting off to the northeast toward the Great Lakes.
Two things will result for our forecast. One, general northwest flow
will continually nudge colder air into our part of the country. And
two, with main precipitation shield north and west of low center,
our chances will increase as low approaches later Tuesday into
Wednesday.

So for today, southwest to west low level flow will keep coldest air
to our north for much of the day. Plus we should see some sunshine
across much of eastern Nebraska and southwest Iowa save for
northeast Nebraska where thicker mid level cloud cover should
linger. Highs will hold in the 40s there, with low to mid 50s
farther south.

A vort lobe rotating around low center is shown by GFS spreading
some cloud cover across the CWA later today, then clears the way for
colder air to begin its southward trek tonight. 850 temps above 0C
at 00Z are expected to drop to the 0C to 4C below range by 12Z
Tuesday, then settle around 5C below later Tuesday into Wednesday.
Cloud cover will be on the increase Tuesday and Wednesday as mid
level moisture rotates south with colder air. Saturation in
dendritic temperature layer suggests efficient crystal formation
aloft, with low level temperature profile determining what form of
precipitation will reach the ground. Given relatively weak lift on
back side of upper low, will keep precipitation chances small for
the most part, with only light amounts expected where precip does
fall. We will introduce precip chances beginning Tuesday morning in
the north, spreading south toward Interstate 80 by Tuesday afternoon
and evening, then decreasing chance from southwest to northeast on
Wednesday.

High temperatures are expected to drop several degrees each day,
from the upper 30s to middle 40s Tuesday, into the 30s for the most
part on Wednesday.

.LONG TERM...(Wednesday night through Sunday)
Issued at 331 AM CST Mon Nov 28 2016

A mainly dry and cold forecast should hold for the rest of the work
week, with a hint at a slight warming trend this weekend.

Main mid level flow pattern will feature a broad trough over much of
the country, locking in our colder temperature regime at least
through Friday. Temperatures Thursday and Friday should hold in the
30s for highs. By the weekend, more of a split flow pattern is
emerging from model output as westerlies develop across the northern
tier of states and a nearly cut-off low develops in Mexico. The GFS
and Canadian models offer this solution, while the ECMWF is not as
strong with the upper low and keeps more troughing across the middle
of the country. In any event, what warming we could see will
certainly not be robust, but highs in the 40s both Saturday and
Sunday should feel a little warmer than previous days. However if
ECMWF is correct, we won`t see even that amount of recovery.
Forecast will follow the more optimistic GFS/Canadian solutions.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1112 AM CST Mon Nov 28 2016

VFR conditions through most of the period with winds the primary
concerns. West winds at TAF issuance at 11 to 24 knots, diminishing
by 23-00z to less than 12 knots. MVFR clouds do develop at KOFK by
29/14z. Some of the models are also hinting at some light snow at
KOFK 29/16-18z but probability is only 20% at this time.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

SHORT TERM...Dergan
LONG TERM...Dergan
AVIATION...DeWald



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