Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kdvn 230812 
afddvn

Area forecast discussion
National Weather Service Quad Cities Iowa Illinois
312 am CDT Fri Aug 23 2019

Synopsis...
issued at 236 am CDT Fri Aug 23 2019

Pleasant weather is on tap across the upper Midwest as high
pressure passes to our north over the next 24 hours. Currently
high pressure is centered over southwestern Ontario with a few
high clouds across the area. At 3 am, temperatures across the area
ranged from 53 degrees at Freeport to 64 degrees at Burlington and
Keokuk. Dewpoints were generally in the mid to upper 50s.

&&

Short term...(today and tonight)
issued at 236 am CDT Fri Aug 23 2019

Models are in very good overall agreement through the short term.
The main forecast concerns over the next 24 hours are
temperatures.

High pressure will bring quiet and pleasant weather to eastern
Iowa northwest Illinois and far northeast Missouri over the next
24 hours. At the surface, the center of the high pressure will
move across southern Ontario through 12 UTC Saturday. This will
keep easterly winds across the area which will pull slightly
cooler air than we had in place across the area yesterday. 850 mb
temperatures will cool by 3 or 4 degrees through the day on Friday
with the cooler air over my far northwest Illinois counties. This
will result in high temperatures ranging from the mid 70s in far
northwest Illinois to around 80 degrees in far northeast Missouri.
This will also result in temperatures being a couple of degrees
cooler on Saturday morning.

Long term...(saturday through thursday)
issued at 236 am CDT Fri Aug 23 2019

While there are several periods of pops in the forecast for the week
ahead, centered on a cold fropa Monday into Tuesday, I have little
doubt the week ahead will be mainly dry, with a remarkably pleasant
end to meteorological Summer. Highs this weekend, as the high
pressure shifts east, will not be able to tap any significant
southwest flow before this upcoming cold front, thus they will
likely stay in the mid to upper 70s for the weekend. While some
models like the Gem show some moisture being drawn up towards Sunday
night and Monday, an upper wave lifts northeast ahead of the cold
front, the GFS and European model (ecmwf) both are supportive of dry weather ahead of
the cold front, as the low level flow does not support much moisture
transport from the south, at least this far west. This leaves the
cold front forcing, and any moisture along it to be the driver of
any rainfall that occurs along it. I am certainly not a big fan of
high pops for cold frontal rains unless there's a wave riding along
the front. At this time, I will maintain the model blend, which is
high chance to lower likely, but I am quite certain that a
widespread significant rainfall in our County Warning Area is not going to take
place. Amounts expected to average below 1/2 inch, and in many
cases, may be well under 0.25.

For Wednesday through the end of the week, an upper low will
dominate our weather. That would make for a lousy forecast in
January, but a great forecast for late August! Highs will drop to
the lower 70s by late week in this pattern, with a very low threat
for a shower, in the cool air aloft regime.

This pattern should break down and become progressive
northwesterly flow again by next weekend.

&&

Aviation...(for the 06z tafs through 06z Friday night)
issued at 1239 am CDT Fri Aug 23 2019

High pressure will bring VFR tafs through the period. MVFR
visibilities are possible 9 to 12 UTC but confidence is low that
they will occur and have left them out of the tafs. Expect fair
weather cumulus to develop after 15 UTC with ceilings around 4500
ft and raise to 6kft during the afternoon.



&&

Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&

$$

National Weather Service Glossary of Abbreviations