Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 181733

Area Forecast Discussion
National Weather Service Topeka KS
1233 PM CDT Sat Mar 18 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 254 AM CDT Sat Mar 18 2017

Northwest flow aloft is supporting a surface high pressure across
the northern plains. This ridge axis will push through the area
during the day today therefore winds stay relatively light and
gradually veer. Temperatures should start out in the 30s this
morning and warm into the 60s this afternoon with mostly sunny
skies. Tonight a ridge aloft progresses over the plains causing
the lee side trough to deepen. The deepening pressure will support
a low level jet that will advect warm moist air northward. This
moist warm nose will be accompanied by modest mid level lapse
rates, which will yield some elevated cape. The model consensus is
for cape to be about 1500 j/kg with the NAM suggesting as high as
2400 j/kg. This is likely due to the high moisture bias this time
of year. With the elevated instability in place the nose of the
low level jet should provide some forcing for isolated to
scattered storms. If the cape can be realized perhaps some small
hail will be possible. There is a chance parcels could be unstable
over central KS in the early morning hours although the forcing
from the low level jet may not be enough for storm development.
Also, the GFS soundings shows that over central KS the moisture is
not as deep, lower in the profile, and a weak mid level cap. The
models do agree that this is more likely over portions of eastern
KS around the predawn hours therefore have kept the chances for
storms there after midnight.

.LONG TERM...(Sunday through Friday)
Issued at 254 AM CDT Sat Mar 18 2017

Have some lingering slight chances for thunder in the eastern
counties as the overnight convection that may form on the nose of
the LLJ moves eastward, and should end by mid morning. Mid level
temperatures in the teens to low 20s bring high temperatures up
into the 80s across the area Sunday afternoon.

Next boundary moves southward into the area through the day
Monday but still only cools highs into the 60s north to mid 70s
south. Overnight lows fall from 50s the previous night to 40s
Monday night. As this boundary lies across the Central Plains
Tuesday and Wednesday, and small impulses move through the upper
flow over the boundary, we start seeing some periodic chances for
rain, possibly mixed with some snow into early Wednesday. Highs
Tuesday and Wednesday forecast in the 50s.

By Thursday morning, area is forecast to undergo transition from
zonal flow aloft back to southwesterly flow aloft, bringing
return flow back over the state, along with some instability and
chances for thunder. EC and GFS keep adjusting track and speed of
the western trof, but for now will carry higher chances Thursday
morning as the front lifts back northward, and then after a
break, as the main trof approaches will keep increased PoPs on
Friday into Friday evening as current runs have the upper low on
our western doorstep by that hour. Both tracks would linger some
wrap around precip into early Saturday. For now, worth noting that
could see a chance for strong to severe storms Thursday and
Friday, but there is considerable uncertainty in timing, strength
and track overall.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1226 PM CDT Sat Mar 18 2017

VFR conditions are expected today and this evening, with winds
veering to the E/SE as high pressure currently overhead slides to
the east. VFR to MVFR cigs will overspread the area after 04-06Z
with the possibility of an isolated thunderstorm across portions
of east central Kansas late tonight after 09Z.




SHORT TERM...Sanders
AVIATION...Skow is the U.S. government's official web portal to all federal, state and local government web resources and services.