Scientific Forecaster Discussion
fxus63 kdvn 132249
Area forecast discussion
National Weather Service Quad Cities Iowa Illinois
549 PM CDT sun Oct 13 2019
..00z aviation update...
issued at 130 PM CDT sun Oct 13 2019
Upper level occluded low still affecting the area this afternoon
as it slowly moves north and east of the area. Clouds have
filtered down across the area this afternoon. However, unlike
yesterday, the cloud shield is showing signs of scattering out,
suggesting that by daybreak the area will be clear of clouds.
These clearing skies and cooler temps are the main concern in the
short term forecast period.
Short term...(this evening through monday)
issued at 130 PM CDT sun Oct 13 2019
Main forecast concern for the short term are the frost/freeze
headlines across the area. After perusing more data it is clear
that the Highway 20 corridor in Iowa along with our far western
counties have seen a growing season ending freeze. The rest of the
area may have been below or 32 for a couple of hours, however we
do not think that it was enough to kill all of the plants. As such
we plan to keep issuing freeze and frost headlines until a hard
freeze occurs or additional information is received by the office.
There will be places that have an advisory that could see plant
damage and thus the end of the growing season, however we feel
that until a hard freeze occurs over a wide area of that County we
will err on the side of caution and continue to issue these
products. As such, a frost advisory is warranted across the rest
of the area tonight.
There is some uncertainty in temperatures tonight, we could see
lower temps and some areas may see freezing temps. However the
expected duration of these freezing temps is expected to be short
and that is why a frost advisory will be issued instead.
Tomorrow, looks to be a repeat of today but with lighter winds. It
may actually be a more pleasant day across the area.
Long term...(monday night through sunday)
issued at 157 PM CDT sun Oct 13 2019
Active long term forecast with two chances for precip in the
period. The first will be Monday night into Tuesday as warm
advection will bring in showers and storms to the area for the
early morning. This is associated with a northwest flow system. The next
is a deep trof moving in from the SW late in the week through the
weekend. This system looks to have plenty of moisture for heavy
rain and thunderstorms at this time. Temperatures will return to
the 60s and 70s for this late week system.
The first system is just coming on shore across the western US and
Canada. This system could be slower as it moves across the area
and we could see afternoon showers and possibly a rumble of
thunder. The main message with this system is that moisture return
will be limited, thus overall rainfall amounts will be low.
Morning elevated convection is the best chance for rain and
storms. Right on the heels of the warm air advection we will see the sfc front
with rather weak convergence. If the system slows down, we may see
this front enter the area slower and may allow for better moisture
return. This would increase our chances for afternoon showers and
storms, however this does not seem like the reasonable solution.
The system late in the week looks like a strong system with strong
cyclogensis across the area. There is a leading wave for the end
of the week that will bring shower and storms to the area along
with warm advection storms Saturday night into Sunday. Sunday
looks like strong deepening sfc low will track east of the area
and lead to thunderstorms and heavy rain. If the current GFS is
correct, then we would probably see strong storms. A lot can
change in a week so confidence in specifics is low at this time.
Aviation...(for the 00z tafs through 00z Monday evening)
issued at 548 PM CDT sun Oct 13 2019
VFR will rule the taf cycle, with winds light westerly.
Iowa...frost advisory from 11 PM this evening to 9 am CDT Monday for
Cedar-Clinton-Des Moines-Henry Iowa-Jackson-Johnson-Jones-Lee-
Illinois...frost advisory from 11 PM this evening to 9 am CDT Monday for
Bureau-Carroll-Hancock-Henderson-Henry Illinois-Jo Daviess-
MO...frost advisory from 11 PM this evening to 9 am CDT Monday for