Area Forecast Discussion
Issued by NWS Topeka, KS

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388
FXUS63 KTOP 192336
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
636 PM CDT Thu Apr 19 2018

.SHORT TERM...(This evening through Friday)
Issued at 250 PM CDT Thu Apr 19 2018

Little sensible weather is forecast for the end of the work week
aside from a shift in winds to the southeast and an increase in
mid to high clouds.

A meridional surface ridge bifurcated northeast Kansas early this
afternoon with surface winds gradually shifting from northeast to
east as the ridge axis passes through. Aloft, a broad ridge of
high pressure extended from the western Great Lakes to the Rockies
with a meridional trough axis over the Great Basin breaking off
from the northern stream flow and transitioning into a cutoff
low. The upper level low translates slowly eastward tonight and
tomorrow, positioned near the Four Corners region Friday
afternoon.

H500 height falls ahead of the approaching low allow for a broad
and weak lee cyclone to develop along the Front Range on Friday.
Winds increase slightly from the southeast during the day on
Friday as the pressure gradient tightens over the state ahead of
this low. High temperatures will be similar to today, albeit a
few degrees warmer owing to increased BL mixing. Forecast
soundings show high and mid-level clouds spreading into the
region throughout the day on Friday and have increased sky grids
accordingly to account for these trends.

.LONG TERM...(Friday night through Thursday)
Issued at 250 PM CDT Thu Apr 19 2018

Saturday looks to be unseasonably cool and damp, with temperatures
returning to near normal values by Monday.

The aforementioned cutoff low meanders ESE across the Central
Plains between Friday night and Sunday night with the attendant
surface low taking a track across the Southern Plains into the
Lower Mississippi River River basin. The stronger Fg forcing and
kinematic support remain south of the forecast area, with mid-
level moisture transport and isentropic upglide fueling the
majority of the precip over the area on Saturday. As a result,
overall QPF amounts are fairly low with a gradient of higher
values the further south one goes. The slow nature of this system
means that clouds will linger through most of Sunday before
clearing out Monday or Tuesday.

WAA increases Monday into Tuesday with H850 temps rising to +7 C
by Tuesday morning. This will push highs to near normal for this
time of year. A surface baroclinic trough dives across the area
on Tuesday, but confidence in the timing and impacts of this
system are on the lower side given the progressive flow pattern in
place. A WNW flow prevails through the end of the week, with a
modified downslope airmass keeping the region near normal for
temperatures.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 634 PM CDT Thu Apr 19 2018

VFR conditions expected through the period. Light east winds
become southeast and increase into Friday. Smoke from prairie
fires today could bring down visbys briefly at TOP/MHK overnight
but not enough concern at this point to change a flight category.

&&

...Update to aviation forecast discussion...

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

$$

SHORT TERM...Skow
LONG TERM...Skow
AVIATION...67



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