Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 301128
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
628 AM CDT Sun Apr 30 2017

.UPDATE...
Issued at 617 AM CDT Sun Apr 30 2017

11Z observations and web cams indicate a transition to snow in the
Holdrege and Lexington areas with light snow starting to
accumulate. Temperatures in the areas with snow are around 33F to
34F. Snow is also being reported in Mccook/Hill City areas with
precipitation falling as rain farther east.

&&

.SHORT TERM...(Today and tonight)
Issued at 430 AM CDT Sun Apr 30 2017

It`s a complicated short term weather forecast as an upper low
pressure system in the Texas panhandle lifts northeast through
Oklahoma into south central Kansas and then tracks into northeast
Kansas today/tonight. Widespread rain has developed with this
system across our area in good dynamics/isentropic
lift/frontogeneis. So far the precipitation has been predominately
rain overnight, however we have had a few reports of snow mixing
in at times, and even had a period of rain/sleet at our office.

Models remain consistent with the track of the system bringing
additional widespread precipitation across our area today and
through the evening before winding down tonight. Precipitation
type however is not clear cut. Much of the precipitation through
the first part of the day will mainly be rain and some of the
short term models suggest the potential for sleet versus snow at
times, which would limit snow amounts, and models have also slowed
the timing of the rain mixing with or changing to snow. Snow
accumulations (of any significance) are no longer expected by
daybreak with only a few areas in our west seeing accumulating
snow during the morning. Because of this have had to lower the
predawn and morning snowfall amounts which have ultimately lowered
the expected storm total snow.

As the upper low lifts northeast today, a snow band is still
forecast to develop across our western zones which will shift
northeast with time as the upper low lifts into northeast Kansas.
Have kept our current headlines as is for now due to the potential
of a rain/sleet/snow mix at times this morning, with the better
chances for accumulating snow arriving later this afternoon and
evening. Within a snow band later today, and if the thermal
profile remains supportive, have a wide range of 3-8 inches of
snow possible. Outside the snow bands, lesser amounts are
forecast. Confidence on snow totals remain low due to temperatures
remaining above freezing.

Also of note is that mesoanalysis indicates that instability is
not zero and we have had a few reports of thunder in the vicinity
of our cwa overnight. Have not included thunder in the forecast,
but would not be surprised to see a little lightning.

Look for winds will remain strong and gusty all day and into the
first part of the night before beginning to subside in a still
tight pressure gradient. North winds of 25 to 35 mph will be the
rule with gusts of 45 mph. The strong winds combined with any snow
will cause restrictions in visibilities and make for difficult
travel. As the system lifts out tonight the snow will end west to
east. Currently have low temperatures forecast in the low/mid 30s
which is cold heading into the first of May. Have not included
frost in the forecast due to the steady wind speeds but those with
sensitive outdoor vegetation should be aware that temperatures
will be cold.

.LONG TERM...(Monday through Saturday)
Issued at 430 AM CDT Sun Apr 30 2017

At the start of the long term period Monday morning, models are in
good agreement the main upper level low pressure system having
shoved off to the east, set up over central portions of IA by 12Z.
Through the morning hours Monday, lingering PoPs remain across far
northeastern portions of the CWA, as precipitation continues to wrap
around the backside of the low. The afternoon hours remain dry, but
confidence in that isn`t the highest, especially in WNW portions of
the CWA, with some models showing the potential for some additional
light precipitation nosing in with an upper level jet streak. At the
surface, the pressure gradient is finally starting to diminish as
the main low slides further away, but breezy northwesterly winds are
expected through at least the first half of the day. Confidence in
high temperatures isn`t the highest, as how today pans out
(accumulating snow) will play a big part. At this point have lower to
mid 50s across the WNW half, with near 60 in the SE.

Have the dry forecast continuing into Monday night and the morning
of Tuesday, but another disturbance looks to bring precipitation
chances to the area Tuesday into Wednesday. This lower amplitude
shortwave disturbance is shown by models to move in with the
northwesterly flow in place, with the better chances coming after
00Z Wed. More of the focus looks to be south of the CWA, with more
scattered QPF shown by models, so PoPs are in generally in the 20-
40% range. With little/no instability around, kept any thunder
mention out of the forecast. A weak surface pattern looks to keep
winds on the light side Tues/Tues night, with a reinforcing shot of
northwesterly winds for Wed (though speeds even then aren`t notably
higher). High temperatures for both days are in the lower 60s.

Thursday and on through next weekend, the forecast remains dry. As
the midweek disturbance moves out of the area, it continues digging
southeast, developing into a closed low. To the west, ridging is
building north, as another storm system approaches the west coast.
This ridge will slide east onto the Plains, with the latest run of
models showing the main axis overhead this weekend. Will see if
model trends stick with that. Expecting highs to rebound back into
the 70s by Fri.

&&

.AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Monday morning)
Issued at 617 AM CDT Sun Apr 30 2017

Varying visibilities and cloud heights are expected during the taf
period due to periods of precipitation. A potent low pressure
system lifting out of the southern plains will bring widespread
rain which will mix with and change to snow before ending tonight.
Accumulating snowfall is possible especially toward KEAR and north
of KGRI. Cloud cigs will primarily be at IFR to LIFR levels
before raising in the latter taf hours as the system moves out.
North winds will be strong with speeds of 25kts to 30kts and gusts
near 40kts. Speeds will gradually decrease overnight.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Storm Warning until 6 AM CDT Monday for NEZ039-046-060-
     061-072>074-082-083.

     Winter Weather Advisory until 6 AM CDT Monday for NEZ040-041-047-
     062-075-084-085.

KS...Winter Storm Warning until 6 AM CDT Monday for KSZ005-017.

     Winter Weather Advisory until 6 AM CDT Monday for KSZ006.

&&

$$

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



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