Scientific Forecaster Discussion
fxus63 ktop 162338
Area forecast discussion
National Weather Service Topeka Kansas
538 PM CST Sat Nov 16 2019
..update to aviation forecast discussion...
Short term...(this evening through sunday)
issued at 258 PM CST Sat Nov 16 2019
At mid afternoon, a mid level trough was located from Manitoba into
western New Mexico. Mid and high level moisture continued to flow
off the eastern Pacific into the southern and Central Plains as a
cut off mid level low continued to spin off the baja of California.
At the surface, a surface trough and frontal boundary was located
from eastern South Dakota to low pressure in southeast Colorado at
19z. Low level moisture remains relatively dry with dew points
mainly in the 30s down to the Gulf.
Tonight the mid level trough will continue to move southeast into
the Central Plains with the trough axis moving across central and
eastern Kansas Sunday morning. A cold front is expected to move
southeast across the cwa tonight shifting the winds to the northwest
and north. In addition some light rain is possible across far
northeast Kansas as well as along and south of Interstate 35 where
low level moisture will be the highest. A few of the cams are
showing light precip chances through late morning Sunday across
northeast and east central Kansas with the passage of the trough.
Lows tonight will continue to be mild and range from the upper 30s
to lower 40s. Highs Sunday will continue to be mild as well with
readings in the 50s.
Long term...(sunday night through saturday)
issued at 258 PM CST Sat Nov 16 2019
A surface high builds in Sunday behind the front, but then quickly
moves off to the southeast as another frontal boundary moves east
across the cwa on Monday. A fast moving minor shortwave moves
southeast across the Central Plains and then exits northeast Kansas
by late morning Monday. These features are expected to move through
dry as moisture remains limited. Warm advection along with a
building mid level ridge over the southern and Central Plains
Tuesday will bring warm temperatures once again in the 60s for much
of the area into Wednesday. A cut off low is forecast to become an
open wave and eject northeast into the plains Wednesday afternoon
and Wednesday night, while a mid level trough sweeps across the
northern plains and sweeps a cold front through northeast Kansas
Wednesday night. Moisture will increase in the low and midlevels
across central and eastern Kansas with afternoon dew points in the
mid 50s forecast. Both the European model (ecmwf) and GFS show a few hundred Jules of
MUCAPE across eastern Kansas Wednesday evening along with about 50
kts of effective shear and steeping lapse rates. Have introduced a
slight chance of thunder to the forecast, with mainly showers
expected at this time.
Model differences for late next week lead to a low confidence light
precipitation forecast where a mix of rain and snow will be
possible. Temperatures cool off behind the cold front mid week with
highs only int he 40s expected on Thursday and Friday warming to near
50 next Saturday.
Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 528 PM CST Sat Nov 16 2019
A cold front will move through terminals this period, shifting
winds and possibly allowing for a few brief rain showers.
Southerly surface winds will veer to the west then northwest as
the front passes by, which will occur around 09z at kmhk and
around 12z at ktop/kfoe. A few hours of low level wind shear criteria is also
possible at the Topeka airports from about 05z to 08z, with
southwest winds of 35 kts around 1200 feet. Ceilings are also
expected to drop into the low end VFR range near the front, but
tafs currently keep VFR conditions through the period.