Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 151134

National Weather Service Topeka KS
634 AM CDT Sat Oct 15 2016

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 304 AM CDT Sat Oct 15 2016

Broad southwesterly flow aloft per water vapor this morning as an
upper wave deepens as it enters Manitoba. In turn the sfc trough
axis over eastern Colorado shifts into western Kansas by morning,
increasing winds in excess of 50 kts at 900 mb. At the sfc,
sustained speeds between 15 and 25 mph are likely through late
afternoon with gusts in excess of 30 mph. Within the moist airmass
upstream of the sfc trough in northeast Kansas, low level stratus
and fog will once again pose a challenge for todays temp forecast.
Several runs of the NAM, GFS, HRRR, and RAP guidance is showing
decent isentropic ascent below the capping inversion at 850 mb.
With near saturation towards the sfc, patchy drizzle is expected
to develop around sunrise and continue through late afternoon
until the upper trough clears eastward and lower dewpoints enter
north central Kansas. As a result of the drizzle and the
persistent stratus lingering through late afternoon, have lowered
highs today a few degrees from the lower 70s over far northeast
Kansas, to near 80 degrees for north central areas.

For tonight, sfc trough holds over western Kansas with the warm
front centered towards the KS and NE border. Southerly winds weaken
to near 10 mph while low levels once again saturate allowing the
stratus to build back in. Still some uncertainty on the possibility
for widespread fog and/or drizzle with no strong signal of
isentropic lift and low level winds staying up. As the drier air
intrudes on north central areas, lows will fall a bit further into
the upper 50s, with low to middle 60s anticipated elsewhere.

.LONG TERM...(Sunday through Friday)
Issued at 304 AM CDT Sat Oct 15 2016

Sunday and Monday continue to look dry and well above normal for
temps. Models show the low level warm air advection pattern
continuing with a pretty strong elevated mixed layer (EML) capping
the boundary layer. Models show mid level flow gradually becoming
more southwesterly but prog the better dynamics to remain mainly
north of the forecast area. Since forcing does not appear to be
strong enough to overcome the EML, will maintain a dry forecast
through Monday. Highs will be dependent on how much sun there is
since models continue to show low level moisture trapped near the
surface under the EML. Think there should once again be a decent
stratus deck to start the day Sunday. Although models are not as
eager to saturate the low levels for Monday morning. So the
warmest temps are still expected to be on Monday where there
should be more insolation and slightly more mixing of the boundary
layer. Prev forecast temps look reasonable and have only made some
minor tweaks. See the climate discussion below for the
temperatures records at TOP and CNK.

By Tuesday the initial cold front passes through the forecast area
dry due to limited forcing and the decent EML capping the warm
sector. Unfortunately the uncertainty in the forecast increases
for the last couple days of the work week with the GFS cutting off
an upper low and the ECMWF maintaining a more progressive open
wave through the central plains. The GFS has not shown much
consistency in locating the closed low and the spaghetti plot of
its ensemble members show quite a spread in solutions with the
upper wave anywhere from the AZ/NM region to the Great Lakes at
12Z Friday. The model consensus has kept a chance for precip in
the forecast from late Wednesday through Friday because of the
operational GFS. While confidence in the GFS is low, the bulk of
the ensemble solutions depict some form of an upper low over the
central U.S. through the end of the forecast period so it is hard
to completely rule out the operational solution. Because of the
lack of confidence have opted to keep precip chances in the 20 to
30 percent range. Forecast soundings and progs of mid level lapse
rates from the GFS suggest there should not be much if any
instability by the middle of next week. With this in mind, only
have rain showers mentioned in the forecast. Temps should trend
cooler for Wednesday and Thursday as some Canadian air gets pulled
south with the amplifying pattern.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 626 AM CDT Sat Oct 15 2016

Tricky forecast this morning with respect to stratus cloud bases.
Majority of obs show MVFR with a gap of drier air between KMHK and
KTOP where deck lifts to VFR temporarily. All short term guidance
points to moisture advection filling in the gap between 13Z and
15Z with high end IFR to low end MVFR stratus holding at all
terminals through 18Z at KMHK and 20Z at KTOP/KFOE. Light, patchy
drizzle is likely under the low stratus during this time frame.
Some uncertainty for tonight in terms of fog potential.
Currently, KMHK sees the highest probability with clearing skies
and calm winds at the sfc. Started off with a mention of MVFR,
but could easily be adjusted as today`s forecast plays out.


Issued at 304 AM CDT Sat Oct 15 2016

Temps are forecast to be near records for Sunday and Monday. The
following are the record high temperatures as well as the warmest
lows for Topeka and Concordia.

Record HighRecord Warmest Low
Sunday 8866





LONG TERM...Wolters
CLIMATE...Wolters is the U.S. government's official web portal to all federal, state and local government web resources and services.