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Area forecast discussion 
National Weather Service Hastings NE
246 am CST sun Nov 29 2015

issued at 243 am CST sun Nov 29 2015

Updated the forecast for overnight into Sunday morning to raise
temperatures several degrees. With cloudy conditions and with
temperatures near steady or rising with the light east component
of wind...we have little chance of bottoming out near 20...and it
will probably be middle to upper 20s by 12z or 13z.


Short term...(this evening through sunday)
issued at 300 PM CST Sat Nov 28 2015

Satellite imagery showing there has been little change in the
upper level pattern..with southwesterly flow in place across the
region...continuing to be influenced by the low pressure system
spinning over the Great Basin. The region remains under area of
larger scale lift ahead of the main system and with upper level
jet energy...and while our radar has shown returns throughout the
day...calls have resulted in very light/no precipitation. The greater
lift and area of more measurable precipitation has remained fairly
stationary today...just off to the southeast of the County Warning Area across SC Kansas into
far southeast Nebraska. Winds continue to be light across the region...driven
by an area of surface high pressure extending from western WI into central
Nebraska. No big surprises with temperatures today...currently ranging from
the middle 20s to lower 30s.

Looking to the rest of the short term period
tonight/tomorrow...models continue to show little in the way of
notable change regarding the main upper level low pressure system.
If the end of the period...the system becomes a
bit more elongated to the northeast...with a further reach into
WY/Dakotas. Similar to the upper level pattern...models are in
good agreement not showing much change in the surface pattern across
the region...with the remaining under the influence of a ridge
axis extending well northeast to high pressure eventually setting
up over eastern Canada.

Main concern through the short term is precipitation/type. Models
are in pretty good agreement showing the best lift for the County Warning Area
occurring just after the end of this forecast period /ending at
00z Mon/...but the area is not completely void of lift prior to
that. Expecting to see broader scale increased lift remain a cant completely rule out precipitation during any
particular period. For tonight...issue is that forecast soundings
continue to show the potential that the saturated layer remains a
more shallow one...mainly across the northwestern half to two thirds of
the County Warning fzdz remains a concern. Across southeastern portions of the
County Warning Area...closer to the better upper jet energy/lift...along with fzdz
potential...could see a chance of fzra/sleet...if /big if/...a
deeper saturated layer can develop. Getting into the daytime hours
tomorrow...thinking that the fzdz potential remains...but once the
atmosphere starts getting more saturated...chance for snow would
take over from fzra/sleet. At this point...because there is still
some uncertainty with how much/if any precipitation occurs...opted
against any headline...but it will need to be closely watched by
evening/middle crew.

Long term...(sunday night through saturday)
issued at 300 PM CST Sat Nov 28 2015

Focus is on the winter storm system Sunday night through Monday

The same low pressure system which moved into the Great Basin
before Thanksgiving remains there today in a Rex block pattern.
The pattern will finally break Sunday and Monday as an upstream
trough moves into the Pacific northwest and causes the system in
the Great Basin move out across The Rockies and onto the plains
Sunday night and Monday. This system will produce a long
duration...widespread wintry precipitation event across the

Precipitation is expected to be ongoing at the start of the
forecast period Sunday night in isentropic lift as indicated on
the 295k surface ahead of the upper low pressure system to west over
the eastern rockies and edging onto the High Plains. Precipitation may
still be freezing drizzle or a wintry mix...prior to transitioning
to snow as moisture deepens and the dendritic layer saturates.

There are a couple of distinct low pressure areas within the
system which are forecast to dumbbell around as the system moves
out with the northern low initially dominant early on...with the
southern low taking over as the system moves onto the plains.
Models are pretty consistent with the evolution/dumbbell of the
system across the plains...but there are differences in the
overall track of the low from southwest to northeast Nebraska. The
GFS is the farthest south and slowest model...while the
NAM/European model (ecmwf) are more similar and farther north however the NAM is
faster moving out the low than the European model (ecmwf). The track/speed of the
system is important on placement of the deformation snow band and
timing/speed will also affect snow amounts. Model run trends have
been toward a slightly slower and slightly farther south solution
and this will need to be monitored closely. Have went with an
ensemble approach for the storm track which brings the potential
for the greatest snow amounts from southwest Nebraska across the northern/northeast Nebraska. We are still looking
for the potential for decent snow amounts from Sunday night into
Monday night especially across our western/northern zones where
amounts of 4 to 6 inches are likely and if the system slows and/or
tracks farther south several inches of more snow are possible.
Snow amounts taper off farther south where the dry slot crosses
and as surface temperatures will be closer to the freezing mark to limit

The brunt of the precipitation is expected to fall overnight Sunday night
through the daytime hours on Monday with the precipitation tapering off
Monday evening/night although some light wraparound snow will
likely persist. These systems tend to be slow to move out and
can see some chance for light snow or flurries lingering into

The upper low finally is forecast to exit Tuesday night bringing a
pattern change for the middle of the week with rising
heights/warmer air moving onto the plains. Dry weather is
forecast middle week on with temperatures dependent upon how much
snow actually falls Sunday night through Monday night and how long it
takes snow to melt in the moderating airmass.

Another trough is prognosticated to reach the plains next weekend...just
beyond day 7/next Saturday.


Aviation...(for the 06z kgri/kear tafs through 06z Sunday night)
issued at 1142 PM CST Sat Nov 28 2015

Ceilings will gradually lower as a winter system pulls into the
Central Plains. There will always be a small chance of freezing
drizzle throughout the forecast...but chances do not really pick
up until very late in the forecast.


Gid watches/warnings/advisories...
NE...Winter Weather Advisory from 6 PM this evening to 6 PM CST
Monday for nez073>077-082>087.

Winter Storm Watch from this evening through Monday evening for

Kansas...Winter Weather Advisory from 6 PM this evening to 6 PM CST
Monday for ksz005>007-017>019.



short term...adp
long term...Fay

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