Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 262009
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
309 PM CDT TUE JUL 26 2016


.Synopsis...
Issued at 308 PM CDT Tue Jul 26 2016

H5 analysis from earlier this morning has a continuation
of broad high pressure across the southern conus and zonal flow
across the northern conus and southern Canada. High pressure was
anchored over the four corners and the Carolinas. North of the four
corners high, shortwaves were noted over eastern Montana as well as
northeastern Nevada and northern Wyoming. The Montana shortwave was
located over central North Dakota this afternoon, while the Nevada
shortwave was approaching far swrn Wyoming. Abundant convective
cloudiness was erupting across southern and western Wyoming this
afternoon, as well as the higher terrain of Colorado. Earlier this
morning, widespread showers and thunderstorms lifted across South
Dakota. Some of this activity triggered some isolated thunderstorms
across far northwestern portions of the forecast area along an
outflow boundary. This activity has since dissipated with some
decent subsidence noted over southwestern South Dakota and
northwestern Nebraska. Skies were mostly clear with 2 PM CDT
temperatures ranging from 83 at Broken Bow to 89 at Ogallala and
Imperial.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 308 PM CDT Tue Jul 26 2016

The main forecast challenge over
the next 24 hours will be the threat for precipitation and severe
weather potential especially this evening. First off, the short
range solutions failed to correctly initialize the South
Dakota/northwestern Nebraska convection this morning which is
problematic for this evening`s forecast. I think this failure in
initialization, will delay the timing of onset of thunderstorms into
the mid evening vs. early evening hours. Thunderstorms should come
at western and north central Nebraska from two sources this evening.
The first is from the west southwest as a shortwave lifts east of
the central Rockies. This will be activity from residual convection
across northeastern Colorado and southwestern Wyoming. The second
area of convection will arise across western South Dakota early
this evening. As this convection tracks east it will throw out a
frontal boundary into northern Nebraska. As this feature moves south
into an increasing low level jet by mid evening, we should see quick
thunderstorm development over north central Nebraska. This activity
will ride to the southeast along the moisture and instability axis,
and will impact mainly areas in the east and southeastern forecast
area. This area of convection may briefly merge with a line of storms
tracking east from the panhandle with the northern area becoming
more dominant by late evening with support from the nose of the low
level jet. Strong mid level wind shear will support supercell
thunderstorms initially with large hail being the main severe
threat. A quick changeover to a cluster of storms with heavy rain
and wind being the main severe threats, will occur during the late
evening hours. Given the expected later timing for thunderstorms in
the forecast area tonight, the threat for large hail and discrete
supercells may be decreasing across northern Nebraska with an
increased threat for a convective cluster and strong winds. Since
the models did a poor job initializing convection this morning,
decided to cut back pops for tonight in the north. Overnight
convection will force a frontal boundary south to the KS/Nebr border
where it will stall Wednesday. Temperatures will be much cooler
north of the front with highs Wednesday in the lower 80s. There will
be a lingering threat for light pcpn behind the front as well
particularly over eastern portions of the forecast area as mid level
waa lifts into central and eastern Nebraska.


.LONG TERM...(Wednesday night through Tuesday)
Issued at 308 PM CDT Tue Jul 26 2016

Mid and long term solutions in fair agreement and will use a blend
for the forecast. Upper ridge has retreated over the desert
southwest placing the northern plains in fast northwest flow with
chances for thunderstorm development nearly every day. Boundary in
place over western Nebraska Wednesday night with upper wave moving
across the northern plains. Thunderstorms to continue along the
boundary through  the evening. Storms will decrease in intensity
and coverage area through the early morning hours. Weak cold front
over the Dakotas will drop south across Nebraska on Thursday with
slight chance pops retained along the front as it progresses
south. Stationary boundary to lie across southwest into the
southeast Nebraska panhandle and will be the focus for isolated
thunderstorms Thursday night into Friday.Highs in the low to mid
80s with cloud cover and thunderstorms Thursday and Friday. Ridge
building east into western Nebraska on Saturday and warm
temperatures return.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 110 PM CDT Tue Jul 26 2016

For the KLBF terminal: Expect high cloudiness this afternoon with
scattered cigs around 20000 ft agl. Cloud cover will increase by
evening with a small threat for thunderstorms from 03z through 09z
Wednesday. Skies are expected to clear toward daybreak Wednesday
with clear skies expected Wednesday morning. For the KVTN
terminal: Showers and thunderstorms are expected to develop by 01z
Wednesday. Some wind gusts to 40 kts are possible in the vicinity
of thunderstorms with visbys as low as 4sm. Overcast skies will
persist into the overnight with cigs around 15000 ft agl. Low
cloudiness is expected Weds morning with cigs falling to 1500 ft
agl.


&&

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

$$

SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Power
AVIATION...Buttler



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