Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 011138
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
538 AM CST Thu Dec 1 2016

.SYNOPSIS...
Issued at 350 AM CST Thu Dec 1 2016

H5 analysis from earlier this evening, had closed low
pressure centered over southwestern Wisconsin with a trough of low
pressure extending south into the Ohio valley. East of the trough,
high pressure was centered over the Bahamas with a ridge extending
north into the Canadian Maritimes. West of the low and trough, a
high amplitude ridge extended from Montana into northern
Saskatchewan. The ridge was being undercut by a shortwave trough
which was located over eastern Oregon and western Idaho. Current WV
imagery overnight had the low over eastern Wisconsin with the
western shortwave now pushing into central Idaho. At the surface,
low pressure was located over the UP of Michigan with a surface high
located over eastern Montana. A decent pressure gradient extended
east of the high from North Dakota into Minnesota. Across western
and north central Nebraska, winds were fairly light from the west
and northwest at under 10 MPH. Skies were mostly cloudy in the
northeastern half of the forecast area, while locations across
southwestern and western Nebraska were clear. Temperatures as of 3
AM CST ranged from 14 at North Platte to 29 at O`Neill.

&&

.SHORT TERM...(Today and tonight)
Issued at 350 AM CST Thu Dec 1 2016

The main forecast challenge will be temperatures. For today, low
to mid level clouds will be slow to push out of the northern and
northeastern forecast area. The NAM12 h85 to h70 layer RH field
seemed to have a good handle on the current cloud situation
overnight and it was utilized for the cloud forecast today. That
being said, skies will remain mostly cloudy in the northern and
northeastern forecast area and this will have a negative impact on
highs. Felt that the guidance temps were too warm across the north
and northeastern areas as clouds should remain in place through
the afternoon hours. This will hold highs back into the lower 30s.
Further south and southwest, skies will be clear to partly cloudy
which will allow highs to reach the upper 30s to around 40. Given
the expectation that skies will be mainly clear to partly cloudy,
guidance temps seemed reasonable for today. For tonight, a
secondary band of cloudiness will track across the northeastern
forecast area. This will help to hold lows in the lower 20s.
Elsewhere under clear skies and with very dry air in place,
overnight lows will fall off into the middle teens.

.LONG TERM...(Friday through Wednesday)
Issued at 350 AM CST Thu Dec 1 2016

Upper level ridging will build northward across the central plains
Friday into early Saturday in response to a southward diving upper
trough across the western part of the country. This will bring
warmer temperatures to the area, with highs in the mid 30s to lower
40s Friday and in the 40s Saturday. The western upper trough will
dig south into northern Mexico by Sunday morning, where it will
become a cut off low. Meanwhile a quick moving shortwave aloft will
move across the central and northern plains. This will send a
Pacific cold front through the area Saturday night into Sunday, but
high temperatures in the wake of the front Sunday will actually be
warmer as a downslope chinook type wind boosts highs into the mid
and upper 40s.

Upper level ridging will quickly build back over the area Sunday
night into Monday ahead of a developing upper trough of low pressure
across the western Conus. This upper trough becomes quite deep by
Tuesday, with southwest flow aloft across our area ahead of the
trough. Models continue to struggle with the evolution of the upper
trough as it progresses into the central portions of the country
Wednesday into Thursday. Both the GFS and ECMWF indicate a strong
band of mid level frontogenesis will be associated with an arctic
cold front that plunges south into the area Tuesday and Wednesday.
This should bring at least some light snow to the region. What is
unclear is if a stronger system will develop, and model continuity
from run to run has been wobbling on this possibility. At least a
handful of GEFS ensemble members support a fairly potent storm, will
continue to monitor. A certainty will be much colder temperatures
Tuesday and Wednesday, as a large chunk of Arctic air currently
across Alaska dives south into much of the country.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 539 AM CST Thu Dec 1 2016

For the KLBF terminal: Expect mostly clear skies over the next 24
hours. Some scattered high clouds with CIGS of 25000 FT AGL are
possible later this afternoon, persisting into the overnight. For
the KVTN terminal: Skies will be broken through mid afternoon with
CIGS around the 4000 FT level. Skies will begin to clear out
there after with scattered high clouds around 25000 FT AGL.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Taylor
AVIATION...Buttler



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