Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 251124

Area Forecast Discussion
National Weather Service Hastings NE
524 AM CST Sat Feb 25 2017

.SHORT TERM...(Today and tonight)
Issued at 435 AM CST Sat Feb 25 2017

Main forecast issue in the short term is temperatures.

Temperatures in Ord have taken a dive and I have adjusted the lows
this morning down to 4 degrees as they have already reached 6
degrees as wind decreases with surface high pressure settling in,
and being in the river valley, cold air sinks easily.  For highs
today, I combined NAM and BCCONSRAW, which generally will run a good
few degrees below general guidance central and north due largely to
snow cover, and pretty close to guidance in our south. Went with
Superblend for Saturday night with lows 15-25.

Flow becomes quasi-zonal behind the previous strong shortwave trough
that moved east of the area yesterday and ahead of another wave that
will move into the Plains very late Saturday night. Expect
decreasing sky cover today, and some increase as the next wave
approaches. The atmosphere is dry, so no precip is expected in
the short term. Wind will be relatively less than what we`ve
experienced lately as the surface high moves east and toward the
southeastern United States.

.LONG TERM...(Sunday daytime through Friday)
Issued at 435 AM CST Sat Feb 25 2017

General overview of this 6-day period:
It`s this forecaster`s first go-round handling these particular
periods, so unfortunately not a lot of personal history regarding
recent model trends, but here are several first

1) Although there are no "major" storm systems on the horizon,
the Monday-Tuesday night time frame is looking fairly pesky
regarding a couple of different fairly light precipitation
chances. The main peskiness lies with potential precipitation-type
issues, including perhaps the kinds where it doesn`t take much to
cause issues (more on that below).

2) Compared to early in the week, confidence is reasonably high
in an overall easier", more straightforward and (at least for now)
officially dry forecast Wednesday-Friday.

3) Temperature-wise, although a FAR cry from our recent record-
setting warmth, a fairly seasonable, generally slightly-above-
normal regime looks to prevail, with highs on most days somewhere
in the 40s to around 50, and the current candidates for the
overall-mildest days looking like being Monday/Friday. Overnight
lows most nights look to bottom out mainly in the low-mid 20s,
with the main slightly milder exception looking like Monday night
with more areas closer to 30.

4) As for potential non-precipitation issues (such as fog/fire
weather), there is currently no mention of either in the forecast
or Hazardous Weather Outlook (HWOGID) due to lack of confidence in
occurrence far enough out in time. That being said, there are a
few periods worth watching just in case. For fog, the main period
of potential concern might be Monday night/early Tuesday morning
ahead of an approaching cold front. As for fire weather, although
no afternoons currently look particularly worrisome for outright-
critical thresholds being met, pretty much any day Tuesday-Friday
is already is showing signs of possible "near-critical" conditions,
especially in our KS zones and less-so farther north into Neb. At
any rate, it`s still a bit early to introduce even "near-
critical" to the HWO product for this possible Day 4-7 issue.

With the main general points covered, will conclude with some more
specific day-to-day details for those who might be interested...

Sunday daytime/night:
If you don`t mind seasonably-cool temps, this is looking like a
fairly decent day with plenty of sunshine and rather light
westerly breezes averaging only 5-15 MPH. About the only
slightly-concerning "catch" is that some models (especially the
NAM) is generating a fairly narrow ribbon of snow/rain potential
during the morning hours over parts of mainly central/east-central
KS in response to a low-amplitude wave passing through quasi-zonal
(mainly west-east) flow aloft along with an upper jet streak, but
perhaps coming uncomfortably close to the extreme southeast
fringes of our CWA (Mitchell County area). For now though, will
continue to leave things dry CWA-wide perhaps this potential
close-call. Temperature-wise, made very little change from
previous most areas, but nudged down mainly the far northern
counties a few degrees to account for lingering snow cover holding
things back a bit. The net result is mid-upper 30s north, low 40s
central and mid-upper 40s KS zones. Despite afternoon relative
humidity (RH) values dropping under 25 percent in KS zones, winds
should be light enough to keep near-critical fire issues at bay.
Turning to Sunday night, still looks dry with light breezes,
allowing low temps to range roughly 15-25 from far northwest to
far southeast. For what it`s worth, the last few NAM/SREF runs are
trying to hint at fog potential mainly in our eastern counties,
but with little support from numerical guidance will disregard
this possibility for now.

Monday daytime-Tuesday night:
This 48-hour period looks to feature the "trickiest" forecasting
of these longer term periods, with at least two somewhat distinct
chances for fairly light but perhaps marginally-impactful
precipitation over varying parts of the CWA. In the big picture
of the mid-upper levels, broad west-southwest flow will prevail
over the Central Plains as a fairly low-amplitude, large-scale
trough gradually shifts out of the western CONUS and across the
central states, with a series of subtle little waves out ahead of
it. This type of pattern can often result in seemingly "little"
forecast issues at the Day 2-4 range growing a bit more
problematic with time, and this could be the case here too. Right
away Monday daytime, have maintained a dry forecast for now with
only increasing clouds and steady south breezes picking up to
around 15 MPH. That being said, this completely dry daytime forecast
may not last, as various models are at least hinting at the
possibility of spotty light drizzle/rain showers, but even then we
are probably only talking a small fraction of the CWA. Temp-wise,
assuming clouds aren`t overly thick, we should see a solid 8-10
degree boost versus Sunday, with a range from mid-40s far north
(perhaps still held down by snow cover a bit) to mid-50s in KS.
Even if the day does stay dry, modest precip chances return to
mainly Neb zones Monday night into Tuesday morning, with the
highest chances in the far north. Although amounts look light,
precip type is admittedly problematic. With this still being 72
hours away, opted to "keep it simple" by sticking with rain and/or
snow, but if models continue showing a warm layer aloft then later
forecasts may soon need to consider a small possibility of
freezing rain and/or brief sleet showers given the slightest hint
of convective instability. Some of this precip-type dilemma hinges
on surface temp trends, which do seem to be climbing upward a bit
versus previous forecasts and should this trend continue it would
in theory make at least freezing rain less of possible threat. As
earlier mentioned, fog could be a Monday night issue as well. At
any rate, there looks to be a brief break in precip chances
Tuesday afternoon behind this initial wave as northwest breezes
pick up behind a cold front, resulting in highs around 5 degrees
cooler than Monday. Then, right away Tuesday night precip chances
return in association with the main large-scale trough axis, but
this time with the best chances focused across our southern zones
mainly KS. Compared to Monday night`s chances, this precip chance
seems to more solidly favor rain quickly changing to snow. We
continue calling for this to be a minor (generally 1" or less snow
event), but for what it`s worth the latest GFS is showing a bit
more snow potential over our southern zones so this bears watching

Wednesday daytime-Friday daytime:
Have already spent plenty of time discussing the various potential
issues in the Day 3-4 time frame, so will be more brief here with
Days 5-7. In a nutshell, the official forecast goes dry and
remains so as the Central Plains transitions to a fairly
inactive/dry looking northwest-flow regime in the wake of the
aforementioned large- scale trough that passes off to the east
Wednesday into Wednesday night. It`s the kind of pattern where at
least some rogue sprinkles/flurries cannot be completely ruled
out, but nothing that warrants a formal mention this far out
either given low confidence in placement/timing. Each of these
days looks somewhat breezy-to-windy, out of the northwest Wed-Thu
and then the south Friday. Accordingly, cooler highs mainly in the
40s look to prevail Wed-Thu before warming back up more solidly
into the 50s for most areas by Friday, although these Friday highs
were toned back 2-3 degrees from previous forecast. Despite the
relatively coolish afternoon temps, the potential for at least
near-critical fire weather exists pretty much each day given the
decent breezes and potential for RH to drop below 25 percent,
especially in the southern CWA.


.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Sunday morning)
Issued at 523 AM CST Sat Feb 25 2017

VFR conditions as a surface high will dominate influence. We could
get a bit of a gust this afternoon as the pressure gradient
increases along with low-level lapse rates, but nothing all that
strong, especially as leftover snow on the ground will inhibit how
much mixing will occur today.




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