Scientific Forecaster Discussion
fxus63 ktop 241202
Area forecast discussion
National Weather Service Topeka Kansas
702 am CDT Wed may 24 2017
..update to aviation forecast discussion...
Short term...(today and tonight)
issued at 254 am CDT Wed may 24 2017
Early this morning an upper low was located across south central Iowa.
This upper low will dig southward across central MO today, then
southeast across the lower MS River Valley tonight.
Most numerical models keep any measurable rainfall east of the County Warning Area.
The 02z experimental-hrrr does show isolated showers developing across the
eastern counties of the County Warning Area during the afternoon hours. The experimental-hrrr
solution may be possible given the proximity of the cold core upper
low across central MO. Though there will be isentropic downglide on
the west side of the 500 mb trough axis that may inhibit showers from
developing across the eastern counties of the County Warning Area. At this time i'll
place in 10 to 14 pops across the eastern counties of the County Warning Area during
the afternoon hours in case an isolated shower develops. If showers
manage to develop, there may be just enough instability for a
possible weak thunderstorm. Low-level cold air advection will continue today, so
high temperatures will once again only reach the mid to upper 60s.
This evening the afternoon cumulus will dissipate and any isolated
showers will dissipate. Skies will clear across the County Warning Area and
overnight lows will drop into the mid to upper 40s. Surface winds
will diminish enough across east central and northeast Kansas for some
patchy ground fog to develop late, since our crossover temps will
be in the mid to upper 40s. Southeast surface winds will increase
enough through the early morning hours across the western half of
the County Warning Area to prevent patchy ground fog formation.
Long term...(thursday through tuesday)
issued at 254 am CDT Wed may 24 2017
Lee troughing develops Thursday as upper ridge builds into the
Missouri Valley. Low levels will see increasing moisture, but the
ridge aloft helps bring and elevated mixed layer in, with 800mb
temps near 20c. Convection may fire in the Central High plains as a
weak wave moves through, but with surface low moving east across
western Oklahoma keep any low level jet well south and the eml in
place, convective opportunities are not impressive. Have kept small
pops going for mainly after midnight into the morning hours in the
northeast where cap is slightly weaker. Instability increases in far
southern counties Friday afternoon near the surface low and will
keep a small pop here as well, though not impressed with forcing.
Next best chance for precip comes late Friday night into Saturday
evening as a shortwave is pushed east across the Central Plains as
the main upper low to the northeast slides east. Local area is again
in the cold sector with this wave with moisture depths again
looking limited, but southerly low level jet could support a
minor severe weather concern Friday night with elevated cape
values near 1500 j/kg. Sunday and Sunday night looking to be the
best bets for dry conditions of the Holiday weekend, with small
precip potential returning Memorial Day as another wave rotates
around the exiting upper low. Highs Thursday return to the 70s
with southerly winds and good insolation, with some potential for
slightly warmer temps Friday if low cloud can dissipate in the
afternoon. Highs Saturday into Tuesday looking fairly steady in
the 70s on modified northwest flow.
Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 651 am CDT Wed may 24 2017
The MVFR stratus ceilings around 1500 feet will mix out after 14z.
VFR cumulus will redevelop this afternoon and perhaps a
rainshowersat ktop and kfoe. The cumulus clouds will dissipate