Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 281756
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
1256 PM CDT SAT MAY 28 2016

.SYNOPSIS...
Issued at 322 AM CDT Sat May 28 2016

The H5 pattern tonight is fairly active across the lower
48 states. Low pressure was located over western Kansas, while
ridging was present across the eastern quarter of the US. This
ridging extended from the Carolinas north to the eastern Great
Lakes. Further west, and north of the low over western Kansas, a
ridge was present over Saskatchewan and Manitoba. Upstream of this
ridge, a trough of low pressure was present from the Alaskan
panhandle south into northern Washington and the Idaho panhandle. As
of the overnight hours, the low had transitioned east and was
roughly centered over Hastings Nebraska as of 1 AM CDT. On the
western periphery of the low, showers extended from Holt county,
southwest into Custer county. This area of showers was very slowly
transitioning east overnight. Across western and north central
Nebraska, skies were cloudy in the east where the showers were
located, to mostly cloudy in the west, where a shroud of high clouds
was present from the sandhills, west to the eastern Nebraska
panhandle. Temperatures as of 3 AM were generally in the lower to
middle 50s...with some upper 40s in the eastern panhandle.

&&

.SHORT TERM...(Today and tonight)
Issued at 322 AM CDT Sat May 28 2016

Today and tonight: Precipitation chances will be the
main forecast challenge over the next 24 hours. For today:  The
upper level low will accelerate northeast today and will make it
into southwest Minnesota by 00z Sunday. As this feature tracks from
south central into northeastern Nebraska this morning into the early
afternoon hours, the threat for precipitation will continue on the
western flank of the low. This is where the best lift associated
with the deformation zone is located. In these areas, have held onto
the highest pops. The threat for precipitation will linger into the
afternoon hours in the northeastern CWA as lapse rates will steepen
in proximity to the closed low. Elsewhere, mainly dry conds are
expected today, thanks to westerly winds, drier boundary layer air
and subsidence behind the exiting low and trough of low pressure.
Breaks in cloudiness are expected by the afternoon hours, which will
allow temperatures to climb into the middle 70s. For tonight, there
will be a limited threat for thunderstorms in the west, then north
overnight. A shortwave trough of low pressure will lift east of the
front range of Wyoming this evening with an increased threat for
thunderstorms in the west this evening. Thunderstorms may hold
together into the overnight hours across the northern CWA INVOF of a
stalled out surface boundary. ATTM confidence in the location of
this boundary is suspect, so will keep pops around 20 percent.

.LONG TERM...(Sunday through Friday)
Issued at 322 AM CDT Sat May 28 2016

The bifurcated polar low currently in place will eventually merge
back into one main low by next weekend and GFS/ECM are similar with
this hemispheric trend. In the meantime, upper ridge anchored over
the Norwegian Sea keeps most of the progressive systems in the
western hemisphere though these systems are small in amplitude
through mid week since a Rex block across AK and into nrn Pac ocean
keeps systems from becoming too organized. However, as upper high
over AK retrogrades to ern Russia, this allows more organized east
Asian upper jet to develop and extend across the nrn Pac which
serves to develop deep upper low by next weekend over the gulf of
AK. The downstream response is to develop a higher amplitude ridge
across the Rockies toward the end of the week. After a cooler mid
week, warmer temps should therefore return by next weekend.

As for specific details, an initially weak upper low develops and
strengthens over the northern Plains Sunday and Monday. A surface
high will be in place across the Midwest behind the departing
upper low now moving through and with mainly zonal flow aloft, a
trough of low pressure will develop along the High Plains area.
This would be a pattern conducive to support serly low level flow
keeping higher dew points in place east of the panhandle, while
drier air begins to surge east in the higher terrain further west.
This should set the stage for the return of thunderstorms forced
along the dryline initially in the panhandle, then closer to the
upper forcing, along the sewd advancing cold front through Monday
night. This agrees with the current Day 3 placement of a slight
risk for severe storms by SPC. If LLJ develops as per GFS Monday
night, initial convection should grow upscale into an MCS or two
from the Dakotas into KS.

After the passage of the strong cold front Monday night into
Tuesday, cooler air will make its way into the area with primarily
subsidence in place across western and north central NE through mid
week. As mentioned earlier, upper ridge build across the Rockies and
will put the area under nwrly flow aloft. The aforementioned cold
front will slow its swd progress in the southern Plains while the
nrn end of the front will continue to race ewd tied to the good
height falls aloft. A reinforcing cold front will move through the
area Tuesday night into Wed and will scour low level moisture from
the area as surface dew point temps fall into the 40s by late Wed.
Again the result should be a mainly dry forecast for the remainder
of the week with cooler temps midweek, but under mainly sunny skies.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1255 PM CDT Sat May 28 2016

While rain showers are expected to stay east of both KVTN and
KLBF today, a scattered to broken cumulus deck will persist
across both terminals through this afternoon. Ceilings are
anticipated to remain above 5000 feet. Otherwise, clouds clear
out tonight with calm winds.

&&

.HYDROLOGY...
Issued at 322 AM CDT Sat May 28 2016

Along the North Platte and main stem Platte river, minor
to moderate flooding continues. At Lewellen and North Platte
moderate flooding will continue for the foreseeable future, while
minor flooding is expected at Lisco and Brady as well. Along the
South Platte river, elevated river stages will continue at North
Platte and Roscoe. North Platte river stages overnight were 8.9 feet
and 6.8 feet at Lewellen and North Platte respectively. Lisco and
Brady were 4.3 and 7.5 feet as of 2 AM CDT. River levels are
expected to remain steady for the next several days.

&&

.LBF Watches/Warnings/Advisories...
None.
&&

$$

SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Stoppkotte
AVIATION...Kulik
HYDROLOGY...Buttler



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