Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 150448

National Weather Service Topeka KS
1148 PM CDT Fri Oct 14 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Saturday)
Issued at 319 PM CDT Fri Oct 14 2016

Visible satellite shows the low clouds are beginning to erode over
portions of central KS. This thinning out and clearing should
gradually move eastward into northeast KS this afternoon. Clouds may
become more scattered this evening, but once the inversion develops
the stratus should build back across the area. A shortwave will move
over the northern US tonight and tomorrow. Ahead of that wave the
low level jet will strengthen over eastern KS through tomorrow
evening. The main concern tonight will be lift within the stratus
layer causing very low ceilings along with drizzle and or fog. The
low level jet should prevent the surface from fulling decoupling.
This may inhibit fog development and prevent drizzle from reaching
the ground. Although there is the chance that visibilities could
reduce to 1 to 3 miles across most of the area, but dense fog should
be unlikely at this point. During the day tomorrow the increased
southerly winds will promote mixing and the erosion of the thin
stratus layer especially in central KS. Tomorrow afternoon lift
within the mix layer along with instability could support isolated
showers or sprinkles mainly over far northeast KS. Steep low level
lapse rates will also allow wind gusts up to 35 mph to reach the

.LONG TERM...(Saturday night through Friday)
Issued at 319 PM CDT Fri Oct 14 2016

Saturday night through Monday, A longer wave length upper level
trough will remain across the western US with shorter wave length
troughs lifting northeast across the northern high plans into the
upper midwest. A down stream upper ridge will gradually build east
from the southern high plains into the lower and MS river valley.
stronger southwest flow aloft across the central Rockies will cause
a lee surface trough to deepen across the central and southern high
plains. The tighter surface pressure gradient across central and
eastern KS will cause southerly winds to increase each afternoon to
15 to 25 MPH with higher gusts. Warm air advection at 850 mb will
cause 850mb temps to increase to 20 to 25 deg C. Sufficiently deep
mixing during the afternoon hours should allow high temperatures
each afternoon to reach the mid 80s with a few upper 80 degree
readings across the southwest counties on Monday afternoon.

Monday night through Tuesday, A lead upper wave will lift northeast
across the central and northern plains. Low-level CAA across the
northern plains will cause a surface front to push southeast across
the CWA late Monday night into Tuesday. The front will move through
dry since all the forecast models show 850mb winds veering to the
southwest and the deeper moisture shifting south and east of the CWA
well ahead of the frontal passage. The stronger ascent ahead of the
H5 trough will remain across the northern plains and upper Midwest.

Tuesday night through Friday, The long range model solutions diverge
with the ECMWF and GEM showing a progressive open upper level trough
moving east across the plains on Thursday. The deeper moisture will
be well south of the CWA but there may be enough ascent to generate
a few showers, as much cooler and drier airmass advects southward
Thursday into Friday. The GFS solution is quite different and digs
the upper trough across the southern and central high plains into a
cut-off upper low across western TX by Friday. The GFS solution
would cause the deeper gulf moisture at 850mb to advect northward
across eastern KS on Thursday into Friday and shows the potential
for heavy rainfall and perhaps elevated thunderstorms Thursday
through Friday morning. At this time I`m leaning more towards the
ECMWF and GEM solutions.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1147 PM CDT Fri Oct 14 2016

Kept LLWS and MVFR to IFR cigs for the overnight hours, adjusted
timing slightly. Also added VCSH for afternoon hours as steep low
level lapse rates below the inversion look to generate showers
moreso in the afternoon. May need these sooner.




SHORT TERM...Sanders
LONG TERM...Gargan
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