Area Forecast Discussion
Issued by NWS Hastings, NE

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KGID 140516
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
1116 PM CST Fri Jan 13 2017

.SHORT TERM...(This evening and Tonight)
Issued at 406 PM CST Fri Jan 13 2017

Conditions remain quiet this afternoon, with upper air and
satellite data showing southwesterly flow setting up across the
region. The main feature of interest, an upper level low pressure
system, has been digging south along the coast of CA, and will
continue to slide south this evening along the Baja. Skies
continue to be mostly cloudy, thanks to upper level cirrus
streaming in from the west- southwest. At the surface, high
pressure sliding east toward the Great Lakes has been the main
feature, keeping winds on the light side and generally east-
southeasterly in direction. Temperatures have worked out pretty
well, with near 20 in the far north to mid 20s in the south.

For tonight, overall little change was needed, still looking at a
dry forecast, though models aren`t too far off to the southeast
of the CWA with the potential for some light freezing
precipitation. With good agreement keeping it out of the CWA, kept
things dry, but will be something to keep an eye on.

.LONG TERM...(Saturday through Friday)
Issued at 406 PM CST Fri Jan 13 2017

Primary forecast concern through the period continues to lie with
the wintry mix of precipitation possible across the entire
region this weekend into Monday.

In the overall big picture, there hasn`t been a big change in how
things look to evolve Sat-Mon. Models continue to show the main
upper level low making its way east across the Baja and into
northern Mexico Sat/Sat night, then starting to take more of a
northeastward shift Sun and on. One would hope that being 24 hours
closer to the event that confidence would see an upward trend, but
that really wasn`t the case today. There was a little more spread
in the track of the low Sun night into Monday with the 12Z run
of models, especially with the GFS, which took a noticably more
eastward shift, passing more along the KS/OK border. The ECMWF was
pretty similar, pushing more north through western KS, with the
NAM/GEM/SREF at points in between. We`ll see if this is a short
term look in the GFS or if things trend this way, but at this
point not putting a lot of weight into it.

Continue to expect the daytime hours on Saturday to be uneventful
across the area, models have held onto that slower northward push
into our area, with chances starting to increase mainly across NC
KS as we get into the evening/overnight hours. Precip chances
will continue on and gradually push north with time as we get
through the day on Sunday, but it`s not looking to be non-stop
precip, it may come more in waves. The main upper level low and
best larger scale lift is still well off to the south-southwest of
the area Sat-Sun, many folks may find precip during this period to
be overall light in nature. Though perhaps light, still a hazard,
as models remain in pretty good agreement with the thermal profile
supporting freezing rain.

The more widespread and heavier precipitation still looking to
favor sliding in from south-north late Sunday night (after
midnight?) and through the day on Monday, as the main upper level
low moves through and the deformation band is becoming more well
defined. The biggest question through the entire event, but
especially Sun night-Mon, is with temperatures, mainly at the
surface. Models have been pretty consistent with a warm nose
aloft, but continue to vary with just where surface temps end up.
At freezing? 1 or 2 degrees above/below? Very little variation
that would make a big difference. Continue to be very concerned
about the threat of freezing rain and ice accumulations, and at
this point things continue to favor the southeastern half of the
CWA having the most impact from ice, and trending down the further
northwest you go, as sleet/snow become bigger players as that warm
nose aloft cools. During the day on Monday, colder air is starting
to make more of a push into the west, increasing the chance for
snow, but across our east-southeast, uncertainty remains with how
much warm (above freezing) air gets pulled north, switching things
to rain. Precip looks to come to an end at some point Monday
evening/night.

In the end, the decision was made to upgrade the Winter Storm
Watch to an Ice Storm Warning across NC KS and Nuckolls/Thayer
Counties of SC NE. This area will be the first to see any freezing
precipitation, perhaps as early as late Sat afternoon/evening, and
at this time has the highest forecast ice accumulation. Current
ice totals in this area are in the 0.25-0.75" range. Kept the
watch going as is across the rest of the CWA, we have a little
more time to work with and hopefully can get better agreement
among models to pin down details. As far as snow totals go, far
western areas have 2- 3" currently in the forecast, tapering off
to the east. Don`t get too caught up in exact amounts quite yet,
expect adjustments to be made as new model data come in, and as
has been mentioned, it wouldn`t take a big swing in temps to have
a notable impact on forecast ice/snow amounts. Winds throughout
the event don`t look too be significant at this point, models have
been fairly consistent showing northerly winds increasing in speed
mainly on Monday. Speeds of 15-20 MPH (w/ higher gusts) are
currently expected.

For Tuesday and beyond, no changes were made to the model blend.
The forecast remains dry, but confidence isn`t the highest in
that, will have to watch for a weak disturbance or two passing
through the region. Thankfully, not looking to see a significantly
colder airmass accompanying this Sun-Mon storm system, and highs
are forecast to rebound back into the 40s by Wed.

&&

.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Saturday night)
Issued at 1112 PM CST Fri Jan 13 2017

Another quiet period for the tafs weatherwise as the approaching
winter storm system will begin to have impacts after this forecast
period. Winds will remain light/variable under the influence of a
weak surface ridge. Cigs are expected to remain at mid/high levels
however have introduced scattered low clouds toward the latter taf
hours.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Storm Watch from Sunday morning through Monday evening
     for NEZ039>041-046>049-060>064-072>077.

     Ice Storm Warning from 6 PM Saturday to noon CST Monday for
     NEZ086-087.

     Winter Storm Watch from Saturday evening through Monday evening
     for NEZ082>085.

KS...Ice Storm Warning from 6 PM Saturday to noon CST Monday for
     KSZ005>007-017>019.

&&

$$

SHORT TERM...ADP
LONG TERM...ADP
AVIATION...Fay


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.