Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 202334
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
534 PM CST Sat Jan 20 2018

.UPDATE...
Issued at 534 PM CST Sat Jan 20 2018

Areas of dense fog have been added to the fcst S and E of the
Tri-Cities tonight into tomorrow...and fog will probably last into
the afternoon S of I-80. A blend of the HRRR and LAMP vsby
guidance are rarely wrong...and they are hitting the fog
possibility hard. The environment is favorable with stratus
lingering HJH/BIE/LNK etc and temps should easily radiate past
peak afternoon dwpts which are relatively moist.

Given skies will become OVC tonight...will probably raise low
temps to the consensus of model 2m temps later on this shift. Want
to wait and see how this stratus evolves this eve.

Will have much more this eve on latest model runs and other misc
thoughts.

&&

.SHORT TERM...(This evening through Sunday)
Issued at 302 PM CST Sat Jan 20 2018

The approaching winter storm is, of course, the focus for the short
term. The main snowband still looks focused just northwest of the
tri-cities. For the past day or so, however, a secondary band is
advertised by the NAM to develop just east of the tri-cities.
However, the trends are farther east with this band, and it might
very well not wind up being an issue for our CWA. Trends are toward
a slower departure for the snow, and if anything, this will likely
mean higher snow amounts for some in the main band, and a better
chance for poor visibility with the wind gusts still expected to
frequently reach near 45 to 50mph Monday morning.

As for freezing drizzle potential, it continues to look like a
distinct aggravation before the big storm hits as most of us will
lie on the cold side of a surface front that stalled to the south. I
backed up the warning time late tonight and added several counties
to include this freezing drizzle potential and converted the rest
of the watch to winter weather advisory starting at 09Z. Our far
south should be warm enough where we will not have to worry so
much about drizzle freezing, which makes things a bit more
complicated.

Overall, I increased amounts with the main snow band in our
northwest and tightened up the gradient on the southeast side.
Part of the advisory area could conceivably need upgraded if wind
causes a bigger issue with snow, but I needed convert the watch
because of the expected winter precip starting tonight with the
freezing drizzle.


.LONG TERM...(Sunday night through Saturday)
Issued at 302 PM CST Sat Jan 20 2018

There is still high confidence that a heavy snow producer in the
works for Sunday night into Monday morning as agreement is firm.
Although trends were edging the main snow band northwest on the
previous runs, the track wobbled a bit farther southeast again.
The 700 mb track still favors the heavy band in our northwest.
Divergent Q vectors in the 500-300 mb level still indicate an
overall increase in large scale lift Sunday evening.

Monday morning winds will be strong and this has been a consistent
forecast. We could be pushing blizzard in our west, but this can
be upgraded if it looks worse than it does now.,

Let the rest of the extended forecast ride for the most part as
most attention was this upcoming winter storm.

&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 534 PM CST Sat Jan 20 2018

Significant Wx: IFR fog/patchy -FZDZ then accumulating IFR snow.

Tonight: VFR to start but IFR stratus CIGs will invade with
greatest chance of dropping vsby at GRI. Pockets of -FZDZ develop
toward dawn. NE winds 7-11 kts. Confidence: Medium

Sun: IFR CIGs in stratus/fog with pockets of -FZDZ. -FZDZ ends as
-SN moves in from the W...first at EAR then at GRI in the 20Z-21Z
timeframe. Plowing/de-icing will be necessary. NE winds increase
to 15-25 kts. Confidence: High

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory from 3 AM Sunday to noon CST Monday for
     NEZ049-063-064-075>077-084>086.

     Winter Storm Warning from 3 AM Sunday to noon CST Monday for
     NEZ039>041-046>048-060>062-072>074-082-083.

KS...Winter Weather Advisory from 3 AM Sunday to noon CST Monday for
     KSZ005-006-017.

&&

$$

UPDATE...Kelley
SHORT TERM...Heinlein
LONG TERM...Heinlein
AVIATION...Kelley



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