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Area forecast discussion...updated
National Weather Service North Platte NE
1114 PM CST sun Nov 17 2019

Update...
issued at 847 PM CST sun Nov 17 2019

Forecast update is in place for light rain showers developing
further south than originally anticipated. Used a blend of short
term models to bring precipitation further to the south.

&&

Short term...(this evening through Monday night)
issued at 253 PM CST sun Nov 17 2019

Near term concerns revolve around the potential for precipitation
tonight for the northern tier of counties. Shortwave trough that
brought light rain showers to the area Saturday continues to move
out of the area. Subsidence and drier air in its wake has allowed
for mostly clear skies to develop by midday Sunday which helped
propel daytime highs into the low to mid 50s across the local area.
Another lobe of energy will drop into the area coincident with a
strong upper-level jet. This will help advect increasing moisture
into the mid-levels yet again and lead to increasing cloud cover
through the late afternoon and overnight into early Monday.
Increasing clouds will lead to light rain chances for areas along
and north of Highway 2 tonight through sunrise Monday morning. No
different thinking than 24 hours ago as thermal profiles remain too
warm for any type of wintry precipitation type and expecting nothing
more than light rain showers as dry air will once again limit quantitative precipitation forecast
amounts to anything more than a couple hundredths at best. Expect
any rain showers to clear out of the area around sunrise on Monday.
With increased cloud cover and moisture, have increased low
temperatures slight which should range from the mid 30s to near 40.

Shortwave ridging will move in from the west during the day on
Monday as the northwest flow locally prevents any appreciable
disturbance from encroaching the area. Will see a strong h85 speed
Max set up over the area with strong wind gusts likely during the
afternoon hours. Momentum Transfer suggests gusts approaching 25 to
35 mph across much of the region with the strongest gusts expected
across the central sandhills into portions of central Nebraska.
Temperatures should manage to add a few degrees compared to Sunday
with highs climbing into the upper 50s to low 60s. Modest height
rises continue into early Tuesday, continuing our stretch of dry
weather. Skies will be mostly clear and with expected light winds
did lower Tuesday morning lows slightly though still favored the
warmer guidance for now.

Long term...(tuesday through sunday)
issued at 253 PM CST sun Nov 17 2019

Beginning 12z Tuesday. Shortwave ridge axis looks to move overhead
sometime in the Tuesday afternoon/evening timeframe. Dry weather
will continue as a result with one last mild day before another
cooldown returns for a few days. Sharp cold front will sweep through
the area early Wednesday morning, leading to some gusty winds to
start the day. Initial frontal passage will likely be denoted by a
wind shift only but as the morning progresses and mid-level
frontogenesis increases, precipitation chances will be on the rise
quickly. Believe pops will peak during the evening Wednesday into
the early morning Thursday as the ingredients come together: left
exit region of upper level jet, strong mid-level frontogenesis
particularly in the h7-h5 layer, and main h5 shortwave and attendant
vort Max arrives. Plenty of cold air will be in place to allow for
precipitation to take the form of snow with limited potential for
any sort of mixture of winter types as little in the way of any warm
nose appears to set up. Will likely see quantitative precipitation forecast amounts increase in
subsequent forecasts as confidence in where small-scale features set
up increases. Thinking the blended approach is too low for now as
both the European model (ecmwf) and GFS deterministic advertise a tenth of an inch or
two across much of the area. The gefs appears to have two clusters
with one in the 0.3-0.5" range and another at 0.05-0.2". Again, not
buying into any particular amount at this point but suggesting that
there's enough evidence to suggest potential for some at least
limited impacts from wintry weather in the Wednesday night and
Thursday timeframe. While precipitation accumulations may be low
confidence for now, the expected cooldown that will arrive with this
system is medium confidence right now. High temperatures will trend
down Wednesday and Thursday with values in the 30s and 40s for
Wednesday and then solidly in the 30s for Thursday. This, too, may
drop in future forecasts as deterministic models are running colder
and the gefs only shows a couple of individual members warmer than
35 at any point during the day on Thursday. Stay tuned.

Temperatures begin to moderate by Friday somewhat as high pressure
moves through early Friday and returns the area into westerly low-
level flow. This westerly flow will allow for a downsloping wind
component and help to bring temperatures back to seasonable norms.
Most chances for precipitation for Friday and beyond will be tied to
the evolution of a cut-off system across the Desert Southwest and a
diving shortwave associated with a separate cutoff situated near the
Hudson Bay. Believe insufficient moisture will be allowed to set up
locally before this system moves in, therefore, have dry conditions
continuing for most if not all locations Friday evening.
Temperatures will climb again back to the 40s and 50s for Saturday
and Sunday. Various nwp suggests the potential for another quick
diving clipper-like system to move in towards the end of the
forecast period, however, discrepancies exist and preclude any
introduction of pops for next weekend with confidence on dry weather
being low at this time.

&&

Aviation...(for the 06z tafs through 06z Monday night)
issued at 1114 PM CST sun Nov 17 2019

VFR is expected overnight, Monday and Monday evening. A strong
cold front will move through western and north central Nebraska
later tonight. Sfc winds will increase Monday morning to
33025g37kt and remain strong throughout the afternoon. Isolated
showers are expected overnight across much of western and north
central Nebraska ahead and behind the front.

&&

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

$$

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