Area Forecast Discussion
Issued by NWS North Platte, NE

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361
FXUS63 KLBF 241143
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
643 AM CDT Mon Apr 24 2017

.SYNOPSIS...
Issued at 334 AM CDT Mon Apr 24 2017

H5 analysis from earlier this evening had a closed low
over the Tennessee valley with a trough extending south into the
Florida panhandle. West of this feature, a low amplitude ridge
extended from the Red river valley north into northern Kansas.
Zonal flow was noted from the Dakotas east to New England. A
shortwave trough of low pressure was noted across the western CONUS
and extended from northern Idaho into western Utah. East of this
shortwave, abundant clouds have developed across the central and
northern Rockies and has lifted east into western Nebraska and the
high plains overnight. Some light precipitation had developed
overnight across western Colorado into Wyoming and the western
Dakotas. Even an isolated thunderstorm or two had developed over
western Nebraska overnight and has since lifted north into the
western sandhills. At the surface, low pressure was anchored from
the northern Nebraska panhandle south into eastern Colorado. A
surface trough of low pressure was anchored from northern portions
of the Nebraska panhandle into eastern Colorado. North of the low, a
cold front extended from southwestern South Dakota into northeastern
South Dakota and west into central Montana. With breezy conditions
present across the eastern two thirds of the forecast area, readings
as of 3 AM MDT were mild with temperatures in the middle to upper
50s.

&&

.SHORT TERM...(Today and tonight)
Issued at 334 AM CDT Mon Apr 24 2017

Today and Tonight: The main forecast issue over the
next 24 hours is precipitation chances. Over the next 24 hours, a
lead shortwave will cross western and north central Nebraska this
morning, followed by the approach of a stronger disturbance tonight.
For today, the lead shortwave will cross the forecast area, clearing
it by mid afternoon. There will be a limited threat for showers in
the west this morning through sunrise, with chances falling off
quickly thereafter. Low pressure, currently over the northern
Nebraska panhandle will lift to the northeast, dragging a weak cold
front into north central Nebraska later this afternoon. The front
will be weak with limited cold air advection behind it. None the
less, behind the front, highs will be in the middle 60s this
afternoon, while south of the front, highs will be in the lower to
mid 70s. A second shortwave will approach the Rockies tonight,
lifting into northeastern Wyoming by 12z Tuesday. The latest NAM12,
GFS and warw solutions develop some convection in eastern Wyoming
this evening, lifting it to the east and northeast overnight. ATTM,
on this track, locations in the west and northwestern cwa will see
the best chances for pcpn overnight. However, the 4KM NAM solution
is a little farther south, tracking the precipitation through the
I80 corridor then into central Nebraska. This solution does have
some limited support from the WARW as well. That being said, didn`t
eliminate pops in the southern forecast area overnight. I did
however, slow down the onset of the precipitation in the west and
confined the mention of thunder to the evening hours only. Looking
at instability progs from the NAM12, lifted indices, both surface
based and elevated, were zero or positive after midnight this
evening so felt the mention of thunder should cease after midnight.
Overnight lows will range from the upper 30s in the north to mid 40s
south.

.LONG TERM...(Tuesday through Sunday)
Issued at 334 AM CDT Mon Apr 24 2017

The long term period will be characterized by much below normal
temperatures and above normal precipitation.

Tuesday will be the first of the chilly and rainy days. Models have
been fairly consistent in tracking a 700 mb low center across
northern Nebraska Tuesday into Tuesday evening. Lift is best across
northern Nebraska and that is where the likely pops will be
maintained. Cold air aloft will be heading south into the area by
Tuesday afternoon on the backside of a surface low. In fact 850 mb
temperatures fall to 5 to 10 degrees below zero Tuesday night.
Lingering light rain will mix or change to wet snow, but
precipitation by this point will be very light and no accumulation
is expected.

Wednesday will be a breezy and continued chilly day. Northwest winds
of 15 to 25 mph are expected in the wake of the Tuesday system. 850
mb temperatures do recover to around 8C across southwest Nebraska by
afternoon, but remain below zero all day across the northeast
portion of the forecast area. Some sun will help highs climb into
the 50s across southwest Nebraska, but across north central
Nebraska, lingering clouds and colder air aloft will limit highs to
the mid 40s.

Late week into the weekend, a large upper level trough will advance
eastward into the central plains. Operational models have been
struggling with the evolution of this system. GFS ensemble mean
insists that a closed system with the potential for beneficial rain
and overnight wet snow continues to look probable. Will keep the
likely pops going based of the mean looking favorable for
precipitation. The cold air remains locked in place with highs in
the 40s to perhaps lower 50s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 643 AM CDT Mon Apr 24 2017

Expect scattered to broken high clouds across western and north
central Nebraska today into this evening. Ceilings will gradually
lower by late evening, falling off to around 2500 FT AGL overnight
tonight. Light rain showers are possible overnight with the best
chances after 09z Tuesday.

&&

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

$$

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



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