340 
FXUS63 KTOP 260541
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1141 PM CST Fri Jan 25 2019

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Saturday)
Issued at 236 PM CST Fri Jan 25 2019

Active northwest flow aloft continues to impact much of the central 
plains in the form of frigid temperatures and several weak systems 
traversing the area through next week.

The first embedded 500 mb wave was noted on water vapor imagery 
passing through central KS this afternoon. There was enough 
isentropic lift around 5 kft to result in scattered snow showers 
through early afternoon towards far east central Kansas. 
Accumulations are not expected and should come to an end by late 
afternoon. Westerly winds are expected to weaken this evening as the 
sfc trough exits. A second elongated wave may impact far northeast 
Kansas by Saturday morning in the form of light snow, otherwise the 
CWA remains dry through the weekend. The latest runs of the NAM and 
GFS MOS guidance are stronger with the westerly downslope flow 
across the state Saturday afternoon, resulting in highs being raised 
Saturday a few degrees to the upper 30s and lower 40s. With the 
exception of far northern Kansas, skies start out mostly cloudy 
before drier air lifts northward during the afternoon, with mostly 
sunny skies returning to northeast Kansas.

.LONG TERM...(Saturday night through Friday)
Issued at 236 PM CST Fri Jan 25 2019

Sunday morning is trending towards clearer skies and warmer lows 
in the 20s, helping to lift highs back into the lower 40s on 
Sunday afternoon.

A much stronger shortwave trough is expected to organize and quickly 
migrate southeastward Sunday night and Monday, increasing chances in 
our area for rain and snow. The bulk of the lift and available 
moisture is consistent between guidance of remaining north and east 
of the area, with less than a tenth of inch of qpf at best through 
Monday afternoon. Precip type is once again tricky as strong 
southerly, warm advection ahead of the wave brings temps into the 
upper 30s by Monday morning before gradually falling through the day 
Monday. Initial precip type looks to be rain through sunrise before 
changing over to light snow or wintry mix mid morning onward for 
areas generally along and southeast of the Kansas turnpike. Little 
to no accumulations are anticipated. What may be more impactful are 
the strong winds to follow Monday afternoon behind the deepening low 
as sfc speeds could come close to advisory criteria ranging from 25 
to 30 mph sustained. Winds will gradually wane by the evening hours 
as high pressure begins to build into the region.

The biggest hazard in the extended period is the extreme cold 
temperatures beginning Tuesday morning with wind chills between 
zero and 10 degrees below zero. These numbers are likely to fall 
even lower Wednesday and Thursday mornings as a poignant sfc high 
invades the central plains. The latest GFS is as much as 25 
degrees colder compared to the ECMWF solution so there are 
uncertainties to the depth of the cold air and location of the 
trough axis. Current forecast is the compromise of both solutions 
with temps in the signal digits with wind chill readings between 
10 and 17 degrees below zero on both mornings. High temperatures 
during this time may only reach the teens to low 20s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1139 PM CST Fri Jan 25 2019

Breaks in the high and mid clouds will allow some patchy freezing
ground fog to develop at the terminals. Visibilities at KTOP may
drop down to 0.5 to 1 sm at times. Visibilities at KFOE and KMHK
may drop to 3 to 4 sm. Later this morning we may see more mid
level clouds which may limit the ground fog potential. Otherwise,
expect VFR conditions through the remainder of the TAF period.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Prieto
LONG TERM...Prieto
AVIATION...Gargan