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Area forecast discussion
National Weather Service North Platte NE
1134 am CST Mon Dec 9 2019

Short term...(today through tuesday)
issued at 329 am CST Mon Dec 9 2019

Near term concerns continue to revolve around quick moving band of
light snow accompanied with strong northwest winds. Surface analysis
depicts a strong cold front that entered western Nebraska late
Sunday night has already cleared the area. As this front moves
through the area, strong fgen at varying levels will be slower to
clear out of the area with lingering lift mainly found in the h7-h5
layer aloft and generally along a North Platte to O'Neill line.
Expectation is for this forcing for ascent to quickly exit the area
over the next few hours, but not before bringing a quick dusting to
areas along and east of the aforementioned line. Believe the hrrr
has the best handle on ongoing activity which carries it east of the
local County Warning Area by 12z. Expect a quick burst of snow from this band with
reduced visibilities and potentially slick roads, but impacts should
be short lived as the band pushes east-northeast at nearly 40 mph. A
look at trends have shown a nearly 1 hpa/hour rise in pressure as a
modest surface high pressure builds into the area through the late
morning. As a result, expect these gusts to continue through midday
before we see a pretty quick decrease for the second half of the
day. Cold air advection will have a strong grip on the region all
day and thus we can expect very chilly high temperatures for Monday.
Temperatures at h85 will fall into the negative teens for much of
the area which puts that near the 10% moving average for North
Platte sounding climatology. About the only thing working in our
favor for daytime highs will be the clearing skies with mostly sunny
conditions expected. That said, still thinking we'll fall well short
of normal temperatures for today with highs only in the 30s and 40s,
or about 5 to 10 degrees below normal. The coldest of these values
will remain over north central Nebraska. Given the cold air and
strong winds, wind chills will drop below zero and approach ten
below zero for the eastern sandhills through north central Nebraska.
Bundle up when you head out the door this morning.

Things to watch tonight will be the potential for light snow
developing across the far northwest as Lee-side convergence
increases downstream from the Black Hills. The GFS and European model (ecmwf) are
betting big on this, with snow chances even continuing even further
downstream through the sandhills and into south central Nebraska.
Believe these outputs are rather bullish considering how much dry
air is in place and lack of stronger lift in the area. For now, have
added flurries to portions of Sheridan into Cherry counties with
expectation that any snow that does develop will likely not
accumulate. Will see low temperatures Tuesday morning fall into the
low 20s for far southwest Nebraska to around ten above for the far
northeast. This is hedging slightly to the warmer side of guidance
with reasons being lack of snow cover on the ground and increasing
clouds through the night. Another southeastward diving surface high
pressure system will glance by the region to the east. This will put
US locally within south-southwesterly low-level flow and help US to
add a few degrees to the high temperatures on Tuesday with a return
of the 40s to far southwest Nebraska and the mid 20s for the far
northeast. Wednesday morning will be quiet once again with low
temperatures falling into low 20s to near 10 southwest to northeast,
similar to Tuesday morning.

Long term...(tuesday night through sunday)
issued at 329 am CST Mon Dec 9 2019

Beginning 12z Wednesday. Period begins with northwest flow aloft and
modest ridging across the central rockies and the next trough to
bring weather to the area over central California. This system will
slide east and begin to phase with a clipper-like system by late
Wednesday to the west. Expecting quiet conditions for the day with
south-southwesterly flow in the low-levels continuing to promote a
slight warm up with daytime highs reaching the mid 40s in the
southwest but remaining in the mid 20s to the northeast. Current
thinking is for the aforementioned trough and Alberta clipper to
split the area, with most energy remaining either north or south of
the area. As such expecting dry conditions to continue through
Thursday and into Friday with moderating temperatures in the 40s and
50s each day. Weak surface cool front moves through on Friday but
thinking fropa will be dry until stronger mid-level forcing in the
form of vorticity advection and frontogenesis can move into the
area. Significant discrepancies abound regarding the weekend system,
its strength, placement, and what it'll bring to western Nebraska.
European model (ecmwf) is much weaker with the system, leaving it an open wave that
focuses across central Nebraska while the GFS is much more compact
and strong with its evolution of the system becoming a cutoff that
brings a strong system that remains just northeast of the area
bringing little in the way sensible weather to US. This is far from
certain in the outcome, but thinking snow chances will return to the
area for the weekend coincident with another cooldown. Have kept
pops limited to "slight chance" and "chance" for now. Expect the
outlook on this system to remain low confidence until beyond the
middle of the week at the earliest.

&&

Aviation...(for the 18z tafs through 18z Tuesday afternoon)
issued at 1112 am CST Mon Dec 9 2019

Latest satellite imagery showed low stratus across the western and
central sandhills has diminished. Latest surface obs continue to
show breezy northwest winds across the area with gusts generally
20-30 mph. The main aviation concerns revolve around ceilings
tonight-early tomorrow and low-end chances for light snow or
flurries tonight. Winds will lessen gradually over the course of
today as broad high pressure currently over southern South Dakota moves to
eastern Nebraska. A weak cold front sagging south that will help aid
light winds across northern neb, along with low-end chances for
light snow and flurries, best chances across northwest Nebraska. Low
confidence in light snow affecting kvtn terminal thus no mention
at this time in the taf. Ceilings will deteriorate to MVFR across
much of northern Nebraska overnight with low-end VFR (less than 7 kft)
spreading across the remainder of the area late tonight-tomorrow
morning. Mostly cloudy skies are then expected to prevail into
early tomorrow.

&&

Lbf watches/warnings/advisories...
none.
&&

$$

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