Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 180800

Area Forecast Discussion
National Weather Service Hastings NE
200 AM CST Wed Jan 18 2017

.SHORT TERM...(Today and tonight)
Issued at 200 AM CST Wed Jan 18 2017

Aloft: The flow remained split over the CONUS with a broad ridge
in the Nrn stream along the US-Can border...and an upr low over NM
with various embedded vort maxima orbiting it. WV imagery showed
one vort max was over TX lifting NNE. It will cont N and arrive
into the fcst area this afternoon and gradually drift into Ern Neb
tonight... while remaining within the broader cyclonic

Surface: 1024 high pres was over MO and encompassed most of the
S- Cntrl USA. This high will move E into the OH/TN Vlys today and
into the Appalachians tonight. Meanwhile...steady return flow will
cont here in the Cntrl Plns.

Now thru sunrise: M/clear over S-cntrl Neb and p-m/cloudy over N-
cntrl KS as high clouds have invaded from the S.

Temps have been very slow to fall overnight. Had to raise low
temps. It wasn`t nearly as cold as this fcstr expected 24 hrs ago.

Today: Gradually increasing clouds from the S as that shortwave
trof approaches and moves in. First 20-25K ft cirrostratus then
accompanied by patches of altocu 12-15K ft.

Given that temps will start the day mild...and where highs ended
up yesterday...added 2-3F to prvs fcst putting the entire fcst
area in the mid-upr 40s. A few spots W of Hwy 183 hit 50F as long
as there are some sunny breaks in the clouds.

There is widespread IFR stratus over TX and it will lift N into
OK by daybreak and across KS into S-Cntrl Neb during the
day...though probably breaking up some. Stratus will become
widespread over the fcst area tonight...probably with some fog.

Tonight: Becoming cloudy/foggy. The last 2 runs of the GFS/NAM
are in good agreement on the Wrn fringe of the stratus along the
Wrn border of the fcst area (Ord-Lexington-Beaver City). Since
this is a favorable location for dense fog...included a mention of
vsbys below 1 mile. It could be less than a mile elsewhere...but
this is where confidence is currently highest.

With moist low-lvls and cloud cover...used consensus of model 2m
temps to raise lows 2-4F from prvs fcst.

.LONG TERM...(Thursday through Tuesday)
Issued at 200 AM CST Wed Jan 18 2017

The outer periods into the first part of next week will feature
normal to above normal temperatures along with off and chances for
light precipitation. Tuesday could see another winter storm system
if models remain on track.

An upper low pressure system centered in eastern Nebraska
Thursday will slowly meander north through Thursday night. An
expansive area of stratus associated with this system is expected
to encompass our entire cwa during the day Thursday and lift over
the low level moisture may generate drizzle at times. Fog is also
a concern with guidance and SREF probs high for reduced
visibilities and have added this to the forecast during the
morning. Temperatures are expected to remain above freezing so we
are not looking at freezing precipitation, but have some concerns
that the low clouds limiting insolation will hold back high
temperatures and have trended readings lower.

The upper low pressure system weakens as it lifts into eastern
South Dakota Thursday night, with the low cloud cover beginning to
erode across our western zones. Where low clouds and weak lift
remain, drizzle remains possible. Temperatures are expected to
remain above freezing for pcpn type to remain as liquid through
this time frame. Cannot rule out the potential for another night
of fog within and along the edge of the stratus.

Heading into Friday the low clouds linger across the eastern two
thirds of our area and lift increases again as a shortwave trough
lifts out of Colorado across Neb. Drizzle or a light rain
potential continues into Friday night, with any accumulations
remaining light. Will again need to monitor for fog potential
however have left out of forecast as surface winds transition
westerly overnight.

Over the weekend we will be in between systems with lows tracking
across the Dakotas and the southern plains states. Cold air
advection behind a boundary Saturday night will drop temperatures
a few degrees for Sunday.

Heights rise aloft on Monday and temperatures warm ahead of a
trough deepening in the Rockies. The next storm system is forecast
to emerge onto the plains Monday night and track across either Neb
or KS on Tuesday. The ECMWF is farther north with the track than
the GFS and with timing at the very end of the forecast period, a
lot can change between now and then. Current model progression
brings decent chances for precipitation which may start as
rain/snow before transitioning to all snow. For now it`s a system
to keep an eye on.


.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Thursday)
Issued at 1147 PM CST Tue Jan 17 2017

Significant Wx: IFR stratus will invade Wed eve after 00Z.

Overnight: VFR SKC. We will be watching for some MVFR fog to
form. Temp/dwpt diffs are small in some locations and there is a
lot of moisture around from yesterday. SSW winds 10 kts or less.
Confidence: Medium

Wed: VFR with SCT 25K ft cirrostratus in the Srn sky. SSW-SW
winds under 10 kts. Confidence: High

Wed Eve thru 06Z: VFR to start...but rapidly decaying to IFR as
stratus invades 03Z-04Z per model consensus. S-SSW winds around
10 kts. Confidence: Medium as there is some uncertainty on timing.




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