Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 192009

Area Forecast Discussion
National Weather Service Hastings NE
309 PM CDT Wed Apr 19 2017

.SHORT TERM...(This evening through Thursday)
Issued at 257 PM CDT Wed Apr 19 2017

Focus is on thunderstorm potential the next few hours.

A cold frontal boundary was advancing southeast today, and was oriented
from KJYR to KPHG at 20Z. Convergence along the front will focus
thunderstorm activity across the east/southeast tier or so of our
cwa for a few hours generally from 21Z to 00Z. The primary hazards
from the storms will be large hail the size of golf balls or
greater and damaging winds of 60 mph given instability around
2000 j/kg and effective shear of 30 to 40kts.

Conditions generally dry out behind the boundary as it exits to the
southeast however we may need some small pops for a few showers
tonight along the elevated boundary in presence of mid level
frontogenesis as latest model runs suggest the potential for this.
Pressure rises behind the front average 2 to 4mb and expect
steady/gusty northwest winds into the overnight hours.

Any lingering light precipitation is expected to end by Thursday
morning as dry air and surface high pressure settles across our
region behind the boundary. Thursday is shaping up to be a
generally nice day with highs in the 60s to low 70s. Northwest
wind speeds may become sneaky breezy at times given the deeper
mixing per soundings in the afternoon.

.LONG TERM...(Thursday night through Wednesday)
Issued at 257 PM CDT Wed Apr 19 2017

Precipitation chances return at the end of the workweek as an upper
trough over the Rockies emerges onto the central and southern
plains. Rain chances return to portions of our western zones as
early as Thursday night, however the better chances for rain across
our western and southern zones favor Friday and Friday night. Dry
air to the east will bring a sharp gradient to areas that are wet
or dry and again our far west zones and mainly north central
Kansas stand the better chances for receiving rainfall.
Instability remains pretty meager and have left thunder out of the
forecast with this system.

The upper low departs Saturday and heights rise behind the system.
The weekend time frame is still looking dry, then models are
trending stronger with another wave heading into Monday, so Monday
may not remain a dry period if these trends continue. Late Tuesday
into Wednesday see precipitation chances return but there are model
differences in the track/strength of this next system and details
will be resolved as things get closer.


.AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Thursday afternoon)
Issued at 1159 AM CDT Wed Apr 19 2017

A cold frontal boundary is just about to reach the terminals at
the onset of the TAF period. Winds will be making the switch to a
northerly then a northwest direction behind the boundary. Cigs are
tricky with cloud heights currently varying between MVFR and VFR
however a fairly expansive area of stratus with IFR cigs are noted
behind the front. Have included a tempo group the low cloud cover
for the afternoon hours. The best chances for thunderstorm
activity later this afternoon and evening will be south of the
terminals however latest forecast models suggest the potential for
light post frontal precipitation overnight in the presence of mid
level frontogenesis. For winds, northwest wind speeds will remain
steady and gusty at times into the overnight hours and deep mixing
Thursday may also produce gusts of 20kts or greater.





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