901
FXUS63 KDVN 030800
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
300 AM CDT Wed Jul 3 2024

.KEY MESSAGES...

- Showers and storms are possible on Independence Day as a warm
  front lifts north through the area followed by a cold front.
  There is a Marginal Risk for severe weather for the western
  third of the CWA.

- Active pattern remains through the long term, with near daily
  chances for precipitation somewhere in our forecast area.
  Saturday may be the best chance at a dry day, with slight-
  chance PoPs daily from there.

- Moderate to Major River Flooding continues, with further
  changes to river forecasts expected as we transition from
  predicted rainfall to observed rainfall over the next 36 hrs.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 249 AM CDT Wed Jul 3 2024

As the cold front that brought the severe weather yesterday slowly
moves out, we may continue to see remnant showers and storms,
especially in our southeast this morning. Much of this activity
should be out of the area by 7am-10am.

Weak high pressure will move through the area today, which should
allow for a brief break in the weather. Much of the day should
remain dry, as dry advection works into the area behind yesterdays
system. A weak upper wave will pass through the area today, but we
are not expecting much precipitation from this, due to lacking
moisture. The best chance will be late tonight, where we introduce
slight-chance PoPs to the area, mainly focusing in the south. This
is the area in which the best forcing and moisture will be found,
but confidence remains low on overall coverage of shower activity.
Plus, much of this will be seen well after dark, so you may not even
notice it rained. Any area that receives rain tonight will be
overall low on the accumulation-side. Rather, enough to wet the
pavement for most, with maybe upwards to a quarter of an inch
for some. If we manage to get some embedded thunderstorms, we
may see some higher amounts up to a half inch. Although,
confidence in that is quite low.

Thus, enjoy this brief period of calm weather, as an active pattern
continues throughout the midwest. Temperatures today will be in the
mid-80s, thanks to some sun, cooling off into the 60s once again
tonight. There will be a nice mix of clouds/sun through the day
today, with more cloud cover moving in this evening and tonight.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 249 AM CDT Wed Jul 3 2024

July 4th...Unfortunately, it looks like we will have the potential
to see more showers and storms on Thursday, July 4th. Wave digs
south towards the area through the day, with a weak leading wave
passing through during the morning. The wave moving through that
morning is the remnant wave from the prior night, which may bring
light precipitation to the area. This will fade out through the day,
leaving the focus on the deeper wave pushing towards us. Moisture
return is relatively weak through much of the day, limiting the
coverage until later in the day, when the deeper wave brings a bit
more moisture into the area. Temperatures will be in the mid 80s
through the day, with surface dew points increasing into the mid-
upper 60s, yields upwards to 1000-2000 J/Kg CAPE. This will couple
with 40-50+ KTs of shear, resulting in the potential for some
strong to severe storms. Cold front is expected to come through
that evening, which will be the focus for the strong storms.
Thus, we should get through much of the day without much of a
severe chance. Currently, the SPC highlights our area in a
Marginal Risk (level 1/5) for severe weather. The overall
confidence in the severe threat is low, as it will be
conditional on how much instability we build through the day.
So, the more sun that we get, the more instability we can build.
Although, if we are left with clouds and showers/storms through
much of the day, that will limit destabilization, along with
the severe threat. Will watch this closely, but be prepared for
the potential of a damp cookout!

Friday...Longer range projections suggest upper low complex to
meander eastward acrs WI, with cool pool aloft effects making for
isolated to wdly sctrd instability showers possible acrs the area,
especially north of I-80. Ambient cumulus, a few showers and the
cool pool itself may keep temps in the 70s to around 80, so a below
normal day for July.

Saturday and Sunday...Medium range ensemble patterns hint at rather
broad upper troffiness establishing or more accurately getting re-
established acrs much of the upper midwest by another digging
northern stream upper wave into the upper MS RVR Valley. Hopefully
most of Saturday will be dry ahead of this incoming process with
moderating temps back into the 80s. There may be a few showers and
storms in the north Sat night, but as the upper trof axis slides
overhead, Sunday afternoon and evening may be a better chance for
isolated to sctrd showers and storms to occur. Seasonable temps in
the low to mid 80s Sunday.

Early next week...Upper jet and synoptic scale feature progs suggest
the longer wave upper trof to linger and even deepen acrs much of
the mid to upper MS RVR Valley this period. This would allow for
wdly sctrd shower and storm development in the afternoon heating
under this feature. The unorganized buoyancy pop up type precip
warrants only low CHC POPs at this juncture in time. Near seasonable
to somewhat below normal temps this period.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1150 PM CDT Tue Jul 2 2024

Area of thunderstorms in southeast IA, northeast MO, and western
IL (including KBRL/KMLI) will gradually end overnight. Local IFR
cigs/vis in fog will occur briefly in the wake of the rain
before a cold front brings VFR conds later tonight and through
Wednesday. West winds around 10 knots behind the front.

&&

.HYDROLOGY...
Issued at 455 PM CDT Tue Jul 2 2024

New Today:

Maquoketa River at Manchester is in a Warning now for Minor
flooding.

Mississippi River at Keokuk is now expected to crest in Major
Category.

Discussion...

Overall the forecasts along the MS River have been increased and
are trending to rise slightly faster than prior forecasts.
Locations from Dubuque to Keokuk are expected to crest over their
respective Major Flood Stage levels. At Gregory Landing, a crest
in the Moderate category is expected. The crest is forecast near
Dubuque and Bellevue on July 4th and 5th, with sites from
Fulton to Keokuk seeing a crest between July 6th and 8th.

On the Maquoketa at Manchester, recent heavy rains from earlier
today and rain expected this evening is expected to push it
over flood stage late tonight and early tomorrow morning. It
should drop below flood tomorrow afternoon.

Showers and storms tonight area expected to produce torrential
downpours as we are seeing a very moisture-laden air mass moving
across the area. In addition, some areas may see repeated rounds
of heavy rain-producing storms. Rainfall totals of 1 to 3
inches are possible across much of the area tonight, with
locations south and west of a line from Cedar Rapids, to Iowa
City, to Mount Pleasant, to Memphis possibly seeing 2 to 4
inches or more! There is a Moderate Risk (level 2 of 4) for the
aforementioned area. Flash flooding will be possible. Seek
higher ground if you get a warning and never drive into flood
waters!

Observed rainfall amounts in the past 24 hours upstream of
DeWitt were not as high as forecast. The crest is still expected
to be in the Major flood category, but will be delayed and
slighly lower.

Additional rises are expected on the Iowa, Cedar, English,
Wapsipinicon and Maquoketa river basins.

Additional flood watches and warnings are possible over the
next 24 hours.

&&

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

&&

$$

SHORT TERM...Gunkel
LONG TERM...Gunkel/12
AVIATION...Haase
HYDROLOGY...14