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
FXUS63 KTOP 291720

National Weather Service Topeka KS
1120 AM CST Tue Nov 29 2016

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 304 AM CST Tue Nov 29 2016

Mid/upper level low pressure currently located over the northern
plains and upper Midwest will gradually progress eastward today and
tonight. A weak surface trough in western KS will also move through
eastern KS today. Therefore surface winds will go from westerly to
more northwesterly through out the day. Winds increase once daytime
mixing occurs with speeds around 10 to 20 mph and gusts up to 30 mph
especially in central KS. Mid level clouds will also build in from
the northwest today reaching north central KS this afternoon. Some
stratocumulus may also try to develop around the same time. This
could prevent warming by a few degrees in north central KS. The
highs will range from the upper 40s to the mid 50s. Tonight the wind
speeds will decrease, and clouds continue to move across the area.
Despite the cloud cover a slightly cooler air mass will be in place
causing lows to reach the upper 20s to lower 30s.

.LONG TERM...(Wednesday through Monday)
Issued at 304 AM CST Tue Nov 29 2016

Wednesday through Friday, the deep upper low across the northern
Great Lakes will slowly track northeast into Quebec, Canada. While
another upper trough moves on shore across the pacific northwest and
digs southeast into the Desert Southwest. A broad surface high will
remain across the central and southern plains and will slowly shift
east into the mid MS river valley. This will keep the cool airmass
in place with afternoon highs only reaching the lower to mid 40s and
overnight lows in the 20s.

Friday night through Saturday night, The GFS, ECMWF and GEM
solutions are beginning to converge and show the upper trough across
the desert southwest digging south-southeast into northern Mexico,
then lifting northeast across south then lifting northeast into the
lower MS river valley. The ECMWF and to some extend the GEM show a
northern stream upper trough beginning to phase with the more intense
upper trough across south TX across the central and southern plains.
This could bring a slight chance for some light precip Saturday into
Saturday night. The GFS keeps any precip much farther south across
OK and TX. At this time vertical temperature profiles look warm
enough to keep the precip in the form of light rain on Saturday,
then the light rain may mix with or change to snow as the northern
stream H5 trough axis moves east across the central plains. However,
if the GFS solution proves to be more accurate then we would have
mainly dry conditions on Saturday and Saturday night. Highs on
Saturday will be in the lower to mid 40s with overnight lows in the
upper 20s to lower 30s.

Sunday through Tuesday, The extended model solutions begin to
diverge a bit between the ECMWF and GFS. The ECMWF is much faster
lifting the H5 trough over southeast TX northeast into the east
central US. The GFS has a slower solution and shows a phasing of the
upper trough across south TX with an upper level trough moving into
the northern and central high plains. This may provide enough lift
for light precip Monday night through Tuesday. It looks warm enough
that it would be mostly in the form of rain, however as the northern
stream through moves east across the central plains, there may be
enough cooling aloft for the precip to end in light snow or a light
rain and snow mix late Monday night into Tuesday morning. If the
ECMWF solution verifies then we will remain dry through this period.
Not much change in temperatures with highs in mainly in the mid to
upper 40s and lows in the upper 20s to mid 30s.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1112 AM CST Tue Nov 29 2016

For the 18Z TAFs no major change to the going forecast. VFR
conditions still expected. Winds this afternoon should mix down
but no gusts added as not expecting them to gust over 10kts from
predominant. Clouds build in from the northwest overnight but BKN
layer will probably not be long lasting if it does go that high
coverage wise. Also, concern for LLWS at this point is low as
surface winds should stay strong enough overnight.




SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...Drake is the U.S. government's official web portal to all federal, state and local government web resources and services.