Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 261146

Area Forecast Discussion
National Weather Service Topeka KS
646 AM CDT Sun Mar 26 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 310 AM CDT Sun Mar 26 2017

Matured cyclone over the MO River Valley this morning continues to
advect residual low stratus across eastern KS. Very weak low level
forcing underneath the low clouds has generated patchy drizzle near
the I 70 corridor overnight, but overall has dissipated and shifted
east. Temporary ridge aloft across central KS has brought in the
drier air and therefore the potential for widespread fog on the
western flank of the stratus deck. Current indications are that
visibilities over north central KS, further south towards the
Abilene area may fall close to a mile by sunrise, however not
expecting to see widespread dense fog beyond those values. Haze and
mist are most likely for much of the area through the morning hours
Sunday with lows in the lower 40s.

Lack of mixing in the lower levels during the day will make
it difficult to clear the stratus deck before the next progressive
upper trough arrives in central KS by late afternoon. Despite the
mostly cloudy skies, highs Sunday are several degrees warmer from
the lower 50s north to the lower 60s over east central KS. Did not
make any major changes to the previous forecast with respect to
precipitation. Position of the aforementioned trough axis is mostly
similar between guidance with the exception of the GFS closing off
the low at 560 dam. Regardless, much of the midlevel forcing for
precipitation lies directly underneath the axis, situated across
central KS. Timing of the low from short term guidance hinted at
precip beginning a few hours earlier in central KS aft 4 PM. Warm
front and highest potential for severe weather remains south of the
area into OK, however there is a slight possibility for a few
stronger storms to develop in the late afternoon for areas south of
Interstate 70 corridor near the Flint Hills region. 0-6 km Bulk
shear is in excess of 50 kts while MUCAPE values peak near 600 J/KG.
Hail would be the primary hazard with the strongest updrafts.
Contrary to the previous system, the upper low exits quickly after
12Z Monday. Total rainfall amounts are overall less than half of an

.LONG TERM...(Monday through Saturday)
Issued at 310 AM CDT Sun Mar 26 2017

Mid/upper trough axis will be exiting eastern Kansas Monday morning.
Will leave small chances going in the morning but mid level
subsidence and drying should lead to a dry afternoon. Weak
surface ridging builds south into eastern Kansas Monday night with
damp ground anticipated. Low level winds on the light side from
all guidance, but high cloud may also be returning as the night
progresses. Will need to keep an eye on wind and cloud timing for
fog potential into Tuesday morning.

Next upper trough begins to move out of the Southern Rockies Tuesday
night and takes a slower track through the central CONUS as it
becomes more separated from the northern branch. Though there is
some spread in model solutions, precip chances steadily increase
Tuesday night and persist into at least early Thursday per even the
fastest solutions. Temperature profiles continue to keep all precip
in liquid form, with some suggestions of convection around Wednesday
night. There will be some potential for heavier amounts during this
period, though hard to envision much flash flood potential at this
point. Friday and Friday night continue to look dry before the next
trough digs into the Central/Southern Rockies. Models showing even
greater spreads with this trough, but enough evidence of this
beginning to impact the area for small precip chances Saturday.

Temperatures throughout these periods continue to look generally
steady with lows in the 40s and highs in the mid 50s to mid 60s.
SREF and GEFS are showing several degrees of spread even early in
the forecast likely due to differences in cloud and precip trends.
Have lowered highs Wednesday with precip likely to be fairly


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 638 AM CDT Sun Mar 26 2017

Forecast begins with IFR to LIFR  across KTOP/KMHK/KFOE this
morning with areas of stratus lingering throughout the afternoon.
Weak ridging aloft lifts drier air northward towards terminals,
with some variance in models on timing and coverage of stratus
improving to VFR. Winds are overall light in the low levels so
will need to rely on how thick the cloud layer is during the
afternoon. The next incoming system quickly returns the MVFR
stratus from west to east aft 23Z with coverage of showers and
isolated thunderstorms increasing through 05Z. As sct. showers
persist overnight, cigs once again lower back down to IFR thru
12Z. Some of the forecast soundings are hinting at LIFR or VLIFR
and will need to monitor this possibility.




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