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Area forecast discussion 
National Weather Service North Platte NE
701 am CDT Tuesday Jul 22 2014

Synopsis...
issued at 353 am CDT Tuesday Jul 22 2014

500 mb analysis from earlier this evening has a large area of high
pressure anchored across south central portions of the Continental U.S..
further east...a trough of low pressure extended down the Atlantic
coast of the US. A strong closed low was located just off the
coast of the southern alaskan Panhandle with a trough of low
pressure extending south into the eastern Pacific. Closer to the
central Continental U.S....a couple of shortwaves were noted with a strong
wave over the Dakotas and a secondary shortwave noted over the
nebr Panhandle. At the surface...as of 3 am CDT...a frontal
boundary extended from north of Arthur to Taylor per radar
imagery. Isolated showers and thunderstorms had fired north of the
front across the northeastern Nebraska Panhandle and portions of
north central Nebraska over the past couple of hours. Coverage was
greatest across southern Sheridan...as well as western and central
portions of Cherry County and continues to remain isolated at
best.

&&

Short term...(today and tonight)
issued at 353 am CDT Tuesday Jul 22 2014

The main forecast challenges are temperatures followed by the
threat for precipitation later today. For today...the frontal
boundary...currently over central portions of the forecast
area...will sag south later this morning stalling across
northwestern Kansas by evening. Along the front...temperatures
will surge into the upper 90s across the far southern County Warning Area later
this afternoon. With the front expected to be south of Interstate
80 by early afternoon...highs in the lower 90s look on track for
North Platte...with upper 80s forecast further north in the
sandhills and north central Nebraska. Later this afternoon...the
threat will increase for thunderstorms in a couple of areas in the
forecast area. First...thunderstorms are possible in vicinity of of the
frontal boundary across far southwestern Nebraska...and
second...across the far northwest in vicinity of the southern Black Hills and
Pine Ridge. With respect to the Pine Ridge region...instability
will increase with surface heating with sb convective available potential energy reaching near
2000 j/kg across the southern Black Hills by 00z Wednesday. Cap
strength is a concern for convective initiation...especially south
across the northern nebr Panhandle...so any storms which may
impact the northwestern County Warning Area...will more than likely have to move in from
the northwest. Decided to insert some isolated probability of precipitation in northern
portions of Sheridan County early this evening. Bulk shear across
the northwestern County Warning Area...as well as along the front in the far
southwest will approach 35 to 50 kts later this afternoon and
early evening...so there will be a limited threat for severe
storms. For tonight...in light of the NAM solution indicating
convection into the overnight in the central and eastern County Warning Area...am
having a hard time believing any evening convection can sustain
itself. Especially with the surface focus being well south of the
forecast area...and no low level jet.

Long term...(wednesday through monday)
issued at 353 am CDT Tuesday Jul 22 2014

Canadian high pressure will continue build southeast through the
upper Midwest Wednesday...providing for easterly to southeast wind
and cooler temperatures. Highs Wednesday afternoon will range from
the lower 80s across north central Nebraska...to the lower 90s
across the west and southwest. Isolated storms are still indicated
Wednesday afternoon and into the overnight. Weak upglide and lower
saturation pressure gradients target our western then north
central zone into early Thursday. The activity should be east of
the region /save our far north central zones/ by 12z. Additional
storms may form along a Lee surface trough deepening off the High
Plains during the afternoon hours on Thursday...additional support
from a weak passing disturbance is shown by the NAM and ec. Will
continue slight chance probability of precipitation to account for this. Temperatures
Thursday will warm nearly ten degrees from Wednesday highs for
most places...with upper 80s to upper 90s anticipated. Lows
Wednesday through Friday will be in the 60s.

Friday and beyond....the models continue to advertise a transition
to northwest flow atop the plains as a Pacific northwest shortwave breaks
down the ridge and progresses across southern Canada. The ridge
will re-energize over the western states while the shortwave drops
southeast into the Great Lakes region. A cold front will be forced
through the County Warning Area on Friday...with an additional stronger cold front
due early on Sunday. Highs will transition from seasonal on
Friday...to slightly below average early next week...with lows
remaining in the 50s and 60s.

&&

Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 700 am CDT Tuesday Jul 22 2014

Over the next 24 hours...VFR flight conds are expected at both the
klbf and kvtn terminals. Ceilings will range from 9000 to 15000 feet above ground level
and will be scattered for the most part. The exception will be at
the klbf terminal where some broken ceilings around 9000 feet above ground level are
expected overnight tonight. Winds will be from northeast or east
at around 10 kts.

&&

Lbf watches/warnings/advisories...
none.
&&

$$

Synopsis...clb
short term...clb
long term...Jacobs
aviation...clb

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