Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 162342

Area Forecast Discussion
National Weather Service Topeka KS
542 PM CST Thu Nov 16 2017

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Friday)
Issued at 258 PM CST Thu Nov 16 2017

The warm, moist regime over northeast Kansas is expected to increase
in the next 24 hours as southerly return flow increases in the lower
levels as a elongated sfc trough over the western high plains
translates eastward on Friday. Observational trends in the short
term suggest the stratus deck over Oklahoma accompanied by dewpoints
in the 50s are progged to advect northward later this evening.
Isentropic sfcs particularly at the 290 K and 295 K surfaces advect
positive vorticity advection northward, aided by a strong low level
jet through Friday morning. Areas of drizzle and perhaps a few rain
showers are likely after midnight into Friday afternoon, with a few
hundredths of qpf possible along and east of highway 75. The low
stratus and reduced visibilities towards the sfc persist until
enhanced low level mixing in the afternoon shifts the main
precipitation eastward. Temperatures ahead of the trough and
eventual strong cold front Friday evening are on abnormally warm for
this time of year with readings in the middle 50s this afternoon,
falling to the low and middle 40s tonight with the overcast skies.
Thinking that the precipitation comes to an end by the afternoon
with some insulation in the cloud cover decreasing, have bumped
highs a few degrees into the upper 60s and lower 70s.

.LONG TERM...(Friday night through Thursday)
Issued at 258 PM CST Thu Nov 16 2017

Mid and long-term forecast will yield chances for rain overnight
Friday into early Saturday morning then dry for the Thanksgiving
week ahead with near normal temps expected.

Friday night into Saturday morning, the mid to upper flow pattern
suggests that a well advertised positively tilted trough will swing
through the area with rain chances (albeit cold November rain).
Nonetheless, p-type should stay as rain and caused by some post-
frontal frontogenetical forcing in the H7-H6 levels in conjunction
with a fairly impressive 130kt upper jet streak traversing the area.
Soundings even into southern NE indicate that snow in the column
should fall through a rather deep isothermal layer just at or above
freezing and remain saturated then fall into a sub cloud layer
probably greater than 1kft.  Therefore, am in keeping with all
liquid for now with best rain chances along and north of I-70 before
the H5 trough completely swings through by mid to late morning time
frame Saturday effectively ending precip chances.  Story from here
will be breezy northwest winds with CAA working through the area
during the morning and afternoon time frame.  It is possible that a
wind advisory may need to be issued for at least portions of the
area if not the entire area.  Will likely hold on that for now and
continue to monitor the strength of low level CAA.  Strength of the
winds could bring into the picture elevated fire danger as well
Saturday and part of the Sunday period.

GFS, ECMWF and Canadian solutions are in better agreement the last
couple cycles suggesting a dry week ahead with an amplified western
ridge and eastern trough in place.  Low amplitude shortwaves
periodically make their way through the northwest flow pattern over
the forecast area, but any significant cold air remains to the
northeast of the area.  Therefore, temps should hold around normal
to slightly below normal for short periods.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 538 PM CST Thu Nov 16 2017

MVFR to IFR stratus will spread northward across east central
Kansas this evening, becoming well established by 06Z. Ceilings
will lower to IFR to LIFR overnight with light drizzle leading to
reduced visibilities in some areas. The stratus is forecast to
lift around midday on Friday, though the timing of this clearing
is somewhat uncertain. Southeasterly winds tonight will veer to
the south and increase to 10 to 20 kts after the stratus clears on




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