Area Forecast Discussion
Issued by NWS Topeka, KS

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
FXUS63 KTOP 171727

National Weather Service Topeka KS
1227 PM CDT Mon Oct 17 2016

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 306 AM CDT Mon Oct 17 2016

Water vapor imagery this morning depicts a shortwave trough
lifting northeast into the western portions of North Dakota. In
response, the sfc trough axis currently over central Kansas
gradually lifts and deepens northeast into Nebraska this
afternoon, tightening the pressure gradient and wind speeds as a
result. Sustained speeds this morning are already between 15 and
20 mph, likely to increase from 20 to 25 mph generally along and
south of Interstate 70. Vicinity to the trough axis center over
north central Kansas will temper southwest winds slightly to
around 15 mph sustained. As temperatures start off a few degrees
warmer than anticipated in the middle to upper 60s, warm air
surging northward through the day is forecast to raise high temps
to near record readings. Still some uncertainty as to how well we
mix out the inversion layer at 850 mb. Recent runs of the HRRR and
RAP completely mix out the boundary layer, bringing 23 to 25C
temps down towards the sfc. The NAM has a stronger inversion layer
and even stratus this morning at TOP which is not appearing to pan
out by observational trends. Because of this, believe that the 00Z
NAM may be underestimating the mixing aspect. For this reason, I
went a few degrees warmer than the NAM, closer to the MET and MAV
guidance with highs from the upper 80s to lower 90s. There is a
slight concern for fire weather given the strong winds and lower
dewpoints forecast for today. See the fire weather discussion
below for more details.

For tonight, skies remain mostly clear. All models are trending the
cold front a bit faster through the CWA overnight as winds calm below
10 mph. Not expecting any precipitation, however could see some low
clouds develop ahead of the boundary across southeast Kansas by 12Z.
Dewpoints will quickly drop off into the 30s while lows fall to the

.LONG TERM...(Tuesday through Sunday)
Issued at 306 AM CDT Mon Oct 17 2016

Cooler weather is anticipated for the Tuesday through Sunday
period as a couple pushes of cold air move through the plains.
The initial cold front should be all but through the forecast
area by sunrise Tuesday. This modified pacific airmass should
cool temps off into the 70s for highs Tuesday. The stronger surge
of cold air looks to come in Wednesday night and Thursday with a
little more Canadian influence to the surface ridge. Because of
this highs should fall back into the 60s Thursday. By the end of
the week and over the weekend, mid level heights are progged to
increase as an upper ridge builds in over the southern plains.
This should allow temps to moderate and gradually trend back into
the 70s.

Precip chances do not look all that impressive through the period.
The best forcing appears to move through Wednesday and Wednesday
night as a shortwave moves out of the Rockies and amplifies over
the plains. However the deeper moisture is expected to be just
southeast of the forecast area thanks to the initial cold front,
and there does not appear to be a whole lot of saturation with the
shortwave. There may be an isolated shower Wednesday or Wednesday
night, but given the limited moisture and a general lack of
instability based on the GFS forecast soundings have trended more
towards a dry forecast.

The one thing for later shifts to watch is the potential for some
weak moisture advection into east central KS Tuesday night that
may lead to some elevated showers. The GFS and ECMWF do not push
the front very far southeast of the forecast area on Tuesday.
Some pressure falls along the boundary try to swing 850MB winds
back to the south and develop some moisture advection. If the
front stalls out a little further northwest, elevated precip may
have a better chance of developing over eastern KS Tuesday night.

By Thursday, dry air with little or no large scale forcing is
expected thanks to the developing upper ridge to the south.
Therefore a dry forecast is expected to persist through the


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1222 PM CDT Mon Oct 17 2016

For the 18Z TAFs, no significant changes from the going forecast.
Strong gusty SSW winds around 25-30kt range through the 23Z time
frame expected before calming. FROPA will occur generally after
the 06Z time frame with winds veering to the WNW and remaining
under 10kts the rest of the period. No precipitation expected with
the front.


Issued at 306 AM CDT Mon Oct 17 2016

As the sfc trough lifts northeast this afternoon, much drier air
moves into north central Kansas, dropping minimum humidity values
between 22 and 27 percent in the late afternoon. Southerly winds
remain gusty this morning through sunset at 15 to 20 mph with
gusts up to 25 mph. Main uncertainty is the status of the fuels
in the area. In the past few weeks, low lying areas may have
reached a hard freeze while most locations remained in the lower
30s. For this reason, plan on not issuing headlines for today, but
it is a good idea to be mindful if a controlled burn is planned.


Issued at 306 AM CDT Mon Oct 17 2016

             Record High          Record Warmest Low
     Today        90                     66

  Today   90  65




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