Scientific Forecaster Discussion
fxus63 ksgf 200943
Area forecast discussion
National Weather Service Springfield MO
343 am CST Wed Nov 20 2019
Short term...(today and tonight)
issued at 316 am CST Wed Nov 20 2019
A shortwave over the northern Gulf of California will move rapidly
northeast eventually helping to intensify a sfc low/wave over east
Colorado and shifting it into Iowa by 12z/6am Thu morning. A trailing sfc
front will reach northwest MO into eastern Kansas by that time.
Moisture will move quickly N-NE ahead of the sfc low with strong
low and mid level flow aloft. A few showers will spread into our
far western counties late in the day but better overall chances
will be tonight forecast area wide. A mid level dry slot will
punch in from the southwest quickly after midnight limiting
overall rain amounts with this first wave.
Unseasonably warm temperatures are expected again today (60s maybe
low 70s west of ksgf?) Along with stronger south winds. Extensive
mid level cloud cover may eventually limit mixing and resultant
sfc wind gusts, but even limited mixing should support some 35
mph gusts M/l, especially over western and northwestern cwfa and
sections of the western MO Ozarks plateau. Winds will diminish
somewhat late today/early this evening, but as the sfc low tracks
to our northwest tonight, the winds will will pick up once again.
Also have thunder mentioned tonight with a little bit of
Long term...(thursday through tuesday)
issued at 316 am CST Wed Nov 20 2019
Overview: rainfall (thursday-friday) and maybe a brief changeover
to light/snow flurries (friday night) are the highlights early in
this period. Another storm system may affect the area by Tuesday,
but global models and ensembles are all over the place with the
timing/placement/or even the existence of a central Continental U.S. System.
This latter period is of concern due to traffic with the approach
Thursday-friday: another wave of low pressure along the sfc front
off to our south will bring additional rain chances with the
heavier precip expected Thursday night. Will have to continue to
monitor forecast rainfall amounts for our far southern-southeast
counties along the MO/Arkansas border Thursday night. Another sfc wave
is expected to to develop along the front farther to the south on
Friday as an upper level system moves out into the plains.
Guidance trends have placed this system farther south with time
and we don't expected much precip with this system by late
Friday. Our forecast does have some mention of rain/sprinkles
light snow/flurries Friday night as we turn colder. The light qpf
and marginally low sfc temperatures don't point to big winter
weather impacts. Can't rule out some freezing drizzle Friday night
and will have to monitor for that possibility.
Weekend-monday: looks quiet. A northern stream wave will move
southeast through the northern plains/upper Midwest into to the
upper Ohio River Vly by Monday morning. We should see a warming
trend through the period with very mild temperatures by Monday as
we get mid level height rises.
Tuesday: large discrepancies (low confidence) exist by this time
with regards to the strength of an upstream trough. The European model (ecmwf) has
been very inconsistent run-to-run and much weaker with the latest
00z operational run regarding a potential central Continental U.S. Storm.
The GFS has been more consistent, but varies quite a bit in sfc
low placement. For now the blend does increase rain chances for
Tuesday but will have to monitor forecast trends Tuesday-Wednesday
for this very busy travel period.
Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1129 PM CST Tue Nov 19 2019
Low level wind shear expected tonight at kjln as wind fields increase. Those
elevated winds will mix to the surface at all sites on Wednesday,
making for gusty conditions. Showers are expected toward the end
of the taf period, but significantly lowered conditions will wait
until after this taf period to move in.