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Area forecast discussion 
National Weather Service North Platte NE
642 am CDT Thursday Jul 30 2015

issued at 356 am CDT Thursday Jul 30 2015

500 mb analysis from this evening had strong flow across the northern tier
of states and southern Canada. Closed low pressure was present over
northern Ontario with a trough extending southward to southern Minnesota.
Downstream of the trough...ridging extended from the middle Atlantic
northward into Quebec...while a closed low was present over Nova
Scotia. Across the central and southern Continental U.S....high pressure was
anchored over Texas...Oklahoma...Arkansas and Louisiana. Srly
flow on the western periphery of the high extended from Mexico
northward into The Four Corners tonight and moisture associated with
this flow showed up nicely on WV imagery. At the surface...high
pressure continued to dominate across the Central Plains
overnight with mostly clear skies and light winds. Skies were
clear with the exception of some thin high clouds across far southern
Nebraska. Readings as of 3 am CDT ranged from 57 at North Platte
and Broken 65 at Thedford.


Short term...(today and tonight)
issued at 356 am CDT Thursday Jul 30 2015

A small threat for thunderstorms in the south will be the main
forecast challenge over the next 24 hours...while locations in
the central...eastern and northern forecast area should see dry
conds during the period. For today...high pressure will track
east into Missouri. Srly winds will increase on the back side of
this feature...allowing moisture across push northward into southern
Nebraska. At the surface...winds will be fairly weak...which will
limit boundary layer moisture return...however...h85 winds
increase to 10 to 15 kts this afternoon and increase further to
15 to 20 kts tonight...facilitating decent moisture return in the
850 mb layer. This shows up nicely in the latest NAM and GFS solutions
which push this moisture into the southern third of the forecast area
through overnight tonight. Instability will increase this
afternoon as Theta-E ridging builds into northestern Colorado
and southwestern Nebraska...along with steepening lapse rates and
increased cape. The latest NAM solution indicates a weak cap across
the southern Panhandle and northestern Colorado around 21z and look for any
thunderstorms and rain initiation to occur just off to the west of southwestern and west
central portions of the County Warning Area in vicinity of of the Theta-E ridge. With west
northwesterly flow in the middle levels...thunderstorms should be
confined to the southwestern County Warning Area with convective initiation over the southern
Panhandle and northestern Colorado. Highs today will be in the upper 80s
to near 90 and with full sun expected...weighted highs more
toward the higher mav guidance...which was running 2 to 4 degrees
warmer than the cooler met guidance. Lows tonight will be in the
lower 60s with upper 50s in the west...and will be warmer than
this mornings lows thanks to modest moisture return from the
south later today.

Long term...(friday through wednesday)
issued at 356 am CDT Thursday Jul 30 2015

Friday has the potential to be active. Northwest flow aloft will
bring a weak disturbance across the area. Warm moist air will push
north out of Kansas with a east/west boundary stalled across Nebraska.
Most models focus this boundary to be place for at least isolated
thunderstorm development. Moisture is somewhat limited with precipitable waters
around 1... the NAM is slightly higher. Good
instabiliity along and south of the boundary with cape values
around 2000 j/kg.

Another wave moves southeast across the area for Saturday.
Expecting some remnant outflow boundaries from Friday convection
to assist with development for Saturday. Models in good agreement
focusing the wave across northern Nebraska. The arrival is in the
late morning and think some elevated storms could get going early
in the day...although a better chance occurs in the afternoon and
evening hours when storms are more surface based. Guidance still
brings slightly warmer temperatures with most areas at or above
90...which with rising temperatures due to expanding western thermal
ridge...would seem highly likely. However...concern is clouds
keeping temperatures down. Sided with the warmer temperatures...closer to
guidance as any thunderstorm development is expected to be isolated
to scattered and breaks in the storm should allow for sun to boost
temperatures upward.

Ridge continues to expand east for Sunday with temperatures warmer
yet...lower to middle 90s. Temperatures aloft also warm with a decent cap to
develop. This may result in a dry day...however models generally
do break the cap for the afternoon. While the focus is not
great...I do not feel confident enough to go complete dry for the

Monday remains warm with the next trough moving across the
northern rockies. The trough will cross the northern plains for
Tuesday. The GFS has weakened the strength of the trough from
previous runs...however the ec continues to keep the trough
stronger. Thus low confidence in the extended forecast and will
stay with the model blend for now. Generally flow is still
northwest which keeps US in an active pattern...the main concern
will be temperatures. The GFS is warmer...closer to 90...while the
ec is closer to 80.


Aviation...(for the 12z tafs through 12z Friday morning)
issued at 642 am CDT Thursday Jul 30 2015

For the klbf terminal...expect clear skies today with increasing
middle clouds aon 12000 feet above ground level this evening and overnight. Some
thunderstorms are possible southwest of the klbf terminal and are
not expected to impact klbf. For the kvtn terminal...expect clear
skies over the next 24 hours. Winds at the terminal will shift to
the west...then north this evening at around 10 kts.


Lbf watches/warnings/advisories...


short term...clb
long term...masek

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