FXUS63 KTOP 241734

Area Forecast Discussion
National Weather Service Topeka KS
1134 AM CST Fri Jan 24 2020

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 246 AM CST Fri Jan 24 2020

Initially colder temperatures today quickly begin to give way to
progressively warmer temperatures through the weekend.

Currently, the upper level pattern remains highly amplified which is
not allowing for the exiting winter weather system to move east a
very high rate.  Light snow and low stratus with some reduced
visibilities linger across eastern areas until sunrise or maybe just
after as the deformation zone is slow to pinwheel southeast of
the area. Low level CAA continue to advect into the area today
keeping overall high temperatures suppressed into the upper 20s
and low 30s. Have kept with the lower side of guidance also due to
stratus being slow to clear the area. Only a narrow zone of a
relative dry airmass will allow for partial clearing into the
evening and overnight period as the upstream ridge dampens within
broader northwest flow aloft. Pacific moisture should continue to
spill over into the region. This should reinforce periods of
cloud cover into the weekend. As a result, high temperatures may
be overall lower than previously forecast. Even so, some relative
height rises suggest an overall warmer airmass is lifted
poleward. Weekend high temperatures maintain their warming trend.
Highs will push up into the low 40s and then mid to upper 40s by
Sunday with low temps following suit warming into mid to upper

.LONG TERM...(Saturday through Thursday)
Issued at 246 AM CST Fri Jan 24 2020

Overall, trends in guidance from run-to-run have continued to
hint at a southern shift of any dynamically strong energy able to
interact with lower level moisture into the Saturday night time
frame. As a result, still forecasting dry weather with perhaps
only periods of increased cloud cover over the area through
portions of the weekend.

The northern edge of a low amplitude upstream ridge does work over
the area into Monday allowing high temps to flirt with the low 50s
over central Kansas into east central Kansas.  A temperature
gradient that will be noticeable may be in place too as surface
ridging and a northeasterly breeze develops as a modified Canadian
high pressure cell slides through portions of the area.

The next potential round of precipitation may actually hold until
next weekend.  The Monday night/Tuesday upper trough may exhibit the
best forcing and moisture combo south of the area as depicted by the
CMC/GFS solutions.  The ECMWF still keeps enough moisture poleward
as it phases with some Pacific moisture and a more elongated lobe of
energy is depicted by the ECMWF.  Right now, have kept only slight
to chance POPs for the Monday night into Tuesday period.
Thermodynamics suggest that a rain/snow mix becomes more snow
overnight as profiles cool diurnally and the DGZ becomes more
saturated with the advancing upper dynamics.  This could change back
to more rain before finally exiting the area on Tuesday should
enough low level warm air end up being drawn poleward.   Still too
much variability but regardless, the system appears fairly weak.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1134 AM CST Fri Jan 24 2020

IFR/MVFR cigs are expected to continue on the backside of the
exiting mid level wave over Missouri. Clouds will be slow to clear
from west to east through the period. Expect the mvfr cigs to hold
at TOP and FOE through 15Z while MHK is expected to improve to VFR
around 04Z. Northwest winds around 12 kts are expected to decrease
after 00Z to less than 10 kts as high pressure builds in. Also
MVFR VSBYS may hold at TOP and FOE with mist or haze through 00Z
as well.





NWS TOP Office Area Forecast Discussion