Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service North Platte NE
654 am CDT Friday Oct 9 2015

issued at 350 am CDT Friday Oct 9 2015

Surface high pressure has built into the Panhandle
overnight...forcing a cold front into southern Kansas. Skies have
cleared overnight thanks to invading high pressure...the exception
is in the Panhandle...where some patchy fog has developed over the
past few hours. Further east...across most of western and north
central Nebraska light westerly winds were present...which has
held fog at Bay for the time being. At this have fog mentioned
in the Panhandle counties and will monitor through sunrise for
expansion further east. As it stands right not feel
confident enough to expand this further east based on the westerly
winds. Aloft...ridging continues up the western portion of the
Continental U.S. Into western Canada with a closed low over northwestern
Mexico. Across the eastern 2/3rds of the Continental U.S....broad west to
east flow was noted with a short wave trough extending from The
Arrowhead of Minnesota...SW into northestern Nebraska. As of 3 am CDT
under mostly clear skies...temperatures ranged from 42 at North 49 at Imperial.


Short term...(today and tonight)
issued at 350 am CDT Friday Oct 9 2015

Temperatures today and tonight will be the main forecast
challenge. For today...surface high pressure will track east today
and will be located along the Missouri River by 21z this
afternoon. A tightening surface pressure gradient will develop
across the County Warning Area this afternoon behind the exiting high with 850 mb
winds around 15 kts in the western half of the County Warning Area this afternoon.
850 mb winds are unidirectional to the surface at 21z so decent mixing
will be present later today. The mav and met were nearly identical
with their highs utilized the met guidance for highs
with a slight upward adjustment based on favorable mixing and 850 mb
temperatures which increase into the middle teens in the west by middle
afternoon. This yielded forecast highs in the upper 60s in the lower 70s in the west. For tonight...the surface
pressure gradient relaxes somewhat in the west and tightens in the
east overnight. In fact...h925 winds are in the 20 to 30 knots range
in the far eastern County Warning Area at 12z Saturday with surface winds of 10 to 15
kts. Further west...with a more relaxed pressure gradient...winds
will be under 10 miles per hour overnight. With this in mind...followed
guidance for lows in the west as they were indicative of lower to
middle 40s...along and west of a North Platte to Merriman line. East
of this line...I added 2 to 4 degrees to the met/mav guidance as
expected winds will boost temperatures overnight. This yielded lows in
the upper 40s to lower 50s.

Long term...(saturday through thursday)
issued at 350 am CDT Friday Oct 9 2015

A dry and very warm weekend is in store for much of the central and
northern plains. A plume of warm air aloft will move east off the
higher terrain to the west...with h850mb temperatures of 20 to 24c
Saturday and 24 to 27c Sunday. H700mb temperatures also warm to
near 12c both days. Model sounding data continues to indicate a
westerly component to the wind from the surface through the middle
layer of the atmosphere. The deepest mixing potential appears to be
Sunday...but decent mixing is likely Saturday as well. Both days
will be very warm...with Sunday the day for possible record highs.

Sunday will carry the higher threat for critical fire danger. Low
dew points in the middle 30s to near 40 degrees are expected by late
afternoon west of Highway 83...which when combined with temperatures
in the middle 80s to around 90 degrees produces relative humidity
values of 15 to 20 percent. In addition...westerly wind gusts are
forecasted to reach around 30 miles per hour during the afternoon hours just
ahead of a southward advancing cold front. Will continue to monitor
this fire weather potential closely and continue a mention in the
hazardous weather outlook.

The next concern will be strong wind potential Sunday night into
Monday morning. A potent shortwave will cross the northern plains
Sunday night. This will drive a fierce Pacific cold front through
Nebraska Sunday night. Three hour pressure rises of 9 mb are
indicated in the latest NAM model across northwest Nebraska behind
the front...along with h850mb winds approaching 50 kts. Very strong
cold air advection is expected as well. With such a well mixed
boundary layer in place...feel potential is there for some 40 to 50
miles per hour wind gusts to reach the surface Sunday night.

Tuesday and beyond will continue to be dry under west-northwest flow
aloft. No strong shortwave disturbances or cold fronts are currently
forecasted. Temperatures will be above normal Tuesday and
Wednesday...cooling to near normal Thursday.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 653 am CDT Friday Oct 9 2015

For the klbf terminal...patchy fog will impact the klbf terminal
through middle morning with visbys as low as 1sm. After 15z this
morning scattered clouds around 25000 feet above ground level will persist through
12z Saturday. For the kvtn terminal...expect scattered clouds
around 25000 feet above ground level for most of the forecast period. Some
scattered clouds around 12000 feet above ground level are possible Friday evening.


Lbf watches/warnings/advisories...


short term...buttler
long term...Taylor

National Weather Service Glossary of Abbreviations