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Area forecast discussion 
National Weather Service North Platte NE
552 am CST Thursday Dec 18 2014

Synopsis...
issued at 339 am CST Thursday Dec 18 2014

A surface ridge of high pressure extends across the western Great
Lakes. A substantial area of stratus extends along the western
periphery of the surface high across the western Dakotas and
Nebraska. On the edge of the stratus...locally dense fog occurring in
the Nebraska Panhandle. Across western Nebraska...patchy fog with
current visibilities from 2-5sm. Temperatures ranging from 21 at onl to 25
at Oga and iml.

&&

Short term...(today and tonight)
issued at 339 am CST Thursday Dec 18 2014

Areas of fog favorable to persist through middle morning in the eastern
Panhandle/western sandhills...while patchy fog should last through
late morning across the southeastern zones. Retained mention of
patchy freezing drizzle with patchy fog across southeastern zones this
morning. Very light freezing drizzle currently observed with the fog
at lbf at this time. Lbf forecast sounding indicates some very weak lift within
moist layer near -5c to support freezing drizzle until middle morning.
Once fog Burns off...stratus will slowly clear across the western
zones to near a Cody through Ogallala and Imperial line by middle
afternoon. Through the evening and overnight...clearing to continue
working slowly east to near a Broken Bow and Oneill line by
daybreak.

Milder 850 mb temperatures will move into western Nebraska today...rising to
near 1c by late afternoon. The presence of stratus and lack of deep
mixing will hold temperatures to 28 to 32 degrees mainly east of Highway
83...while areas to the west seeing a return of sunshine should see
highs reach 34 to 39. Favored the warmer mav guidance today...except
held those highs back a few degrees in the west due to existing snow
cover effects.

For tonight...lows to fall to 10 to 15 above across the west where
skies should remain mostly clear. Eastern areas to hold in the upper
teens to near 20 under the influence of stratus. Low level moisture
to be very shallow tonight and more indicative of patchy fog rather
than patchy freezing drizzle from previous forecast. The fog could
be locally dense on the western edge of stratus.

Long term...(friday through wednesday)
issued at 339 am CST Thursday Dec 18 2014

12z Friday and beyond. Forecast concerns in the extended
generally revolve around temperatures. However...there/S
increasing support for quantitative precipitation forecast next week...possibly falling as snow
during the Christmas Holiday. For Friday...model guidance
indicates the Arctic drape will push east leaving mostly clear
skies for much of the forecast area by afternoon. Temperatures
will respond by warming into the middle 30s for most locations.
Lower clouds an/or fog returns however late Friday night into
Saturday. Bufr soundings using the NAM and GFS suggest
differencing degrees of saturation or lack thereof from east to
west across the County Warning Area. The GFS generally more aggressive with the
eastward advance of the Arctic airmass...whereas the NAM keeps the
degree of bl saturation high...and once diurnal cooling
occurs...the model suggests fog. Given the difference...will hold
off on the fog mention in the forecast for now. If it were to
occur...would expect the better saturation to be over the eastern
third of the forecast area early on Saturday. Brief transitory
ridging will build across the northern plains...then advance east
with the approach of a northern plains upper level disturbance.
Most locations will see high temperatures warm a few degrees on
Saturday. Lows will remain in the teens and twenties this coming
weekend. Highs Sunday will continue to trend warmer as lower
tropospheric winds take a slight southwesterly trajectory as a Lee
trough deepens on the High Plains. Widespread 40s should
prevail...with the warmest readings over the southwest and south.

An upper level system will drop southeast across the plains on
Monday...re-enforcing a deepening longwave eastern Continental U.S. Trough.
There will be an increased threat for light quantitative precipitation forecast early next week.
Temperatures support a mix bag of ptypes...which change over to rain
on Monday. Conditions dry Tuesday and midweek in advance of the
next trough to dig toward the Great Basin. Will need to watch this
system as it may bring accumulating snow to the County Warning Area late week and
into next week weekend. After above normal temperatures early in the
week...Arctic air will filter south and take up residence...cooling
temperatures middle week and beyond are expected...with a strong push
of Arctic air possible late next week. This is supported by all
long range deterministic solutions.

&&

Aviation...(for the 12z tafs through 12z Friday morning)
issued at 548 am CST Thursday Dec 18 2014

IFR conditions forecast at klbf and MVFR at kvtn today and much of
tonight. Stratus will slowly clear across the Nebraska Panhandle
and into western Nebraska today. Clearing is expected to progress
east to kvtn by 06z and klbf by 10z.

&&

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

$$

Synopsis...roberg
short term...roberg
long term...Jacobs
aviation...roberg

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