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Area forecast discussion 
National Weather Service Topeka Kansas
242 PM CDT Thursday Oct 8 2015

Short term...(this evening through friday)
issued at 242 PM CDT Thursday Oct 8 2015

A cold front extended northeast to southwest across northeast
Kansas at 19 UTC. Based on the front's progress today and the
latest short range guidance, current thinking is for the front to
move southeast this afternoon and exit our southern counties by 02
UTC. 19 UTC meso-analysis was showing modest instability ahead of
the boundary across eastern Kansas. As the front moves southeast
late this afternoon, there may be enough convergence to initiate
isolated thunderstorms. Model sounding show that surface based
parcels will need to overcome some negative area to get going.
Will keep small pops in the forecast, mainly across our southern
counties early this evening for this possibility.

The next issue concerning precipitation will be from the mid-level
upper trough which is forecast to move through the area tonight.
Both the 12 UTC GFS/NAM both show decent mid-level frontogenesis and
response tonight. However, although the mid-levels saturate and
precipitation will likely develop, it will pass through dry air near
the surface. Therefore, the likelihood of rainfall should be in the
40-50% range.

After the upper trough moves through early Friday, skies should
clear quickly due to subsidence and dry air. Cooler temperatures
for Friday due to cool surface high pressure moving through the

Long term...(friday night through thursday)
issued at 242 PM CDT Thursday Oct 8 2015

The forecast for Friday night through Thursday is highlighted by
some temp swings, but chances for precip appear to be pretty
limited due to a lack of moisture. There are a couple things to
keep an eye on though. The first is Friday night into Saturday
morning. The NAM (and to a lesser extent the gfs) is hinting at
some elevated showers possible within a developing warm air
advection pattern across central Kansas. However the GFS is not as
strong with the isentropic lift nor does it saturate the mid
levels as easily as the NAM. With the European model (ecmwf) and Canadian failing
to generate any qpf, have kept the forecast dry. The other thing
to watch for is the frontal passage Sunday night. Models have
trended to bring some of the stronger dynamics associated with a
shortwave passing across the northern plains further south and
across northeast Kansas. However moisture availability appears to be
limited with the frontal system. Therefore have maintained a dry

Regarding temps, models start bringing the warm air back in on
Saturday, and by Sunday show 850mb temps between 20 and 25 degrees
centigrade. Because of this have highs forecast to warm into the
mid 80s and around 90 Sunday, but there is the potential temps
may be a degree or two warmer Sunday afternoon as some of the
objective guidance wants to warm temps into the lower 90s. With a
dry airmass and good insolation, it may not be out of the
question. By Monday morning, the front is progged to be through
the area with cold air advection lasting for much of the day.
Expecting the cold air advection to hang on through the day, I
blended in some of the raw model data which is cooler than the
consensus to forecast highs in the lower and mid 70s.

The cool down again appears to be short lived next week as
northwest flow aloft allows for warm air from the southwest to
come back Tuesday and Wednesday. There is a little more
uncertainty in the forecast by Thursday as the European model (ecmwf) wants to
bring another frontal system into the region while the GFS is not
as strong with the potential surface ridge. With this in mind,
stayed close to the model consensus of highs in the mid and upper
70s while lows drop into the lower 50s. The coolest mornings are
expected to be Saturday and Tuesday as the surface ridge axis
passes across northeast Kansas. Otherwise lows look to be in the 50s.


Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1218 PM CDT Thursday Oct 8 2015

Much of the taf period will see VFR conditions. A cold front will
make its way into the terminals by mid to late afternoon.
Initially, expect mainly a wind shift with some increasing cloud
cover. There is a small chance of light rain late tonight and
during the overnight hours. Have left vcsh as it is not entirely
clear if a solid line of precip develops north of the terminals
then moves through or develops just to the south of the terminals.
Either way, not expecting a huge or long duration impact to
aviation at this point. Nice conditions prevail after this frontal
system moves through.


Top watches/warnings/advisories...none.



Short term...Johnson
long term...wolters

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