Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 211129
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
629 AM CDT Fri Apr 21 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 331 AM CDT Fri Apr 21 2017

Early this morning, water vapor imagery was showing two nearby
moisture regions which will be contributing to precipitation chances
today through tonight. One area of moisture moving across western KS
and nosing into north central KS is associated with an embedded
shortwave within an advancing mid-level trough that was stretched
across the Rockies.  The second moisture region was located just
south of the CWA, where showers and scattered thunderstorms had
developed along and north of the nearly stationary front located
across Oklahoma and Arkansas.  Short-range models show that this
precipitation across southeast KS may struggle to reach further
north due to the frontal boundary remaining fairly stationary
through the day.  However, we could see scattered showers and
isolated storms extending into portions of east central KS this
morning into the afternoon hours. The better potential for
precipitation across the CWA will come by late afternoon and through
tonight as the mid-level low tracks eastward across southern KS. The
combination of better forcing and available moisture with this mid-
level low should support scattered showers across most of the CWA by
tonight, with the highest QPF amounts looking to be focused across
east central KS.  There is some model uncertainty with the northern
extent of precipitation coverage near the KS/NE border and how
quickly precipitation will diminish across north central KS
overnight as the mid-level low shifts further eastward.  As for QPF
amounts, locations along and south of I-70 may receive 0.5 to 1.0
inch, with higher amounts of 1.0 to 1.5 inches possible along and
south of the I-35 corridor.  Based on the fast-moving nature of this
system and the current flash flood guidance for the region, do not
anticipate the need for a Flood Watch.  However, cannot entirely
rule out the potential for localized minor flooding concerns across
portions of east central KS.

As for temperatures, with either scattered light precipitation or
nearby precipitation across east central KS today, expect the
associated overcast skies to keep conditions cooler across that
region, so have lowered high temperatures into the low/mid 50s.
Further north near the KS/NE border, high temperatures should reach
into the mid/upper 50s. Despite overcast skies tonight, the shift to
northeasterly winds will keep temperatures cooler tonight with lows
in the low/mid 40s.

.LONG TERM...(Saturday through Thursday)
Issued at 331 AM CDT Fri Apr 21 2017

Have kept isolated to scattered showers on Saturday morning with
upper low moving to our east, and should bring an end to showers for
most of the area by the noon hour, save areas southeast of I35
where a few showers may linger into the afternoon. Amounts from
any residual showers are light, generally less than a tenth of an
inch for the daylight hours. Cooler northeasterly winds will hold
highs in the upper 50s to low 60s. Skies clear and winds get light
for Saturday night, with lows dropping into the middle to upper
30s. Think the warmer ground temperatures and recent rains will
help keep frost at bay, but will need to keep an eye on lows.
After the chilly start, highs rise into the upper 60s on Sunday
afternoon under clear skies and a return to southerly surface
winds. These winds stay up overnight and keep lows in the 40s,
with highs on Monday rising into the 70s. Breezy south southwest
winds are forecast to be sustained near 20 with gusts in the 30s.

Upper pattern for Tuesday/Wednesday has some differentiation in the
longer term guidance, but generally brings weak waves through the
zonal flow and a slight chance to chance for some showers, and
generally in the northern areas.  Better chances come Thursday as a
larger scale upper low over the southwest moves toward the Central
Plains. Will keep thunder chances for Thursday, and could be
favorable for strong storms depending on eventual track and timing.
Highs are generally in the 60s and 70s with overnight lows in the
50s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 622 AM CDT Fri Apr 21 2017

For the 12z TAFs, isolated to scattered showers may develop near
the TAF sites by early to mid afternoon with increasing chances
for showers by late afternoon through the evening hours. With
this evening rain, model soundings show VFR cigs gradually
lowering and dropping to MVFR cigs tonight. There is some
uncertainty in the exact timing of these showers as well as when
exactly the evening precipitation will begin to exit east of the
TAF sites. KMHK may see showers ending overnight with KTOP/KFOE
having showers lingering through sunrise Saturday morning. At this
time, the better potential for any isolated thunderstorms looks
to stay just south of the TAF sites, but cannot rule out an
isolated rumble of thunder. Winds through the period will prevail
out of the northeast with occasional gusts near 20kts during the
afternoon.


&&

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

$$

SHORT TERM...Hennecke
LONG TERM...67
AVIATION...Hennecke


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