154
FXUS63 KDVN 170720
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
220 AM CDT Wed Jul 17 2024

.KEY MESSAGES...

- Cooler and drier air continues to spread across the area.

- Dry pleasant weather will continue into the first half of the
  weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 220 AM CDT Wed Jul 17 2024

We`ve devoted a lot of space on this product in the past week
detailing the intricate details of the daily hazardous weather.
Well, we can shorten this up for the next week, as surface high
pressure brings an extended period of dry, pleasant weather.
Today will see cool advection through the day, with dewpoints
slowly lowering from the mid 60s to the upper 50s. Highs today,
should climb to the upper 70s north to the lower 80s central and
south. Some mid clouds will sweep by early in the period, but
the the majority of the day today should be sunny as any
moisture in our atmosphere really drops through the day. PWAT
values currently around 1.25 will drop to around 0.75 later this
afternoon. This evening looks to be outstanding as winds
decrease under 10 mph, and temperatures hold in the lower 70s
through sunset.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 220 AM CDT Wed Jul 17 2024

Very little change in day to day weather is expected Thursday
through Saturday, as surface high pressure remains in control
with dry air keeping our weather benign.

The upper pattern will eventually shift east by Sunday and early
next week, showing a broad upper low pressure aloft meandering
eastward from the Great Plains into the Midwest. Moisture looks
to be limited with this system, but with cooler air aloft and
some weak lift, we could see a few scattered showers and weak
storms as early as Sunday afternoon, but more likely into early
next week. Upper dynamics appear weak, and moisture generally
limited in this pattern, thus the threat for strong storms
appears very low for July.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1236 AM CDT Wed Jul 17 2024

Latest surface analysis has the cold front well south of the
area. Latest 0506Z IR satellite has a few mid level clouds
across parts of southern Iowa and a pocket of broken mid-level
clouds across north central Iowa. Expect the pocket of mid-level
broken clouds to move southeast and impact TAF sites for a few
hours. Otherwise, expect VFR conditions to prevail through the
TAF period. Winds will be light northwest-north and become 10 to
15 KTs during several hours during the TAF period. No
significant weather is expected at this time.

&&

.HYDROLOGY...
Issued at 939 PM CDT Tue Jul 16 2024

Swaths of heavy rain and resultant run-off produced by severe
thunderstorms Monday and Monday night across the area are
aggravating ongoing river flooding or producing new flooding
situations.

The Mississippi River has crested at all sites now, but several will
experience stalled falls or steady trends over the next several days
due to recent bouts of heavy rain, local run-off, and tributary
input. L&D 19 at Keokuk and Gregory Landing will even experience
secondary rises into the weekend.

Tributary Rivers:

Very heavy rainfall on the upper reaches of the Rock River basin
over the past several days, as well as some localized run-off may
produce Major Flooding near Joslin and at Moline by Friday. The
river flood warnings for this have been posted, but there is some
uncertainty that they will actually get that high and Moderate
flooding may be more in line for these sites. The Rock at Como will
be in Minor flood through Saturday evening.

The Pecatonica River basin also received heavy rain, and the site
at Freeport IL is expected to rise well into Minor flood by Friday.

The lower Wapsipinicon River near Dewitt, IA is experiencing
localized run-off from the heavy rainfall last night of 1-2 inches.
It is actually jumping back above flood stage due to this process
and a new warning for that site has been issued this morning. Water
levels are expected to fluctuate around the flood stage through
Thursday night before falling off and maintaining the fall.

Backwater effects from the Mississippi River will keep the lower
Iowa River just below flood stage for the remainder of the week.

Further south, torrential rainfall and run-off from last night may
produce a large rise to action stage on the La Moine River near
Colmar in west central IL. But the extent and speed is still
somewhat uncertain and will have to watch river rise trends through
Thursday.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.

&&

$$

SHORT TERM...Ervin
LONG TERM...Ervin
AVIATION...Gunkel/Holicky
HYDROLOGY...Gunkel