700
FXUS63 KDVN 290745
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
245 AM CDT Sat Jun 29 2024

.KEY MESSAGES...

- After a brief period of quiet weather this weekend, an active
  pattern sets up once again next week, with plenty of chances
  for showers and storms. Heavy rain is possible, but it is too
  soon to determine the severe threat.

- Moderate to Major flooding is expected on several area rivers.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 227 AM CDT Sat Jun 29 2024

Today, the system that brought widespread rainfall to the area will
move out. Aside from some residual showers on the back end of the
system, we are expecting dry conditions for the remainder of the
day. Overall, zonal flow will dominate, becoming more northwesterly
tonight and tomorrow. This will allow for surface high pressure to
move into the area tonight and into tomorrow. With this pattern in
place, we will remain quiet through the short term forecast.
Northwest flow will allow for cold advection to kick in, mainly
tonight and tomorrow, where clear skies and lighter winds tonight
will allow for us to cool off a bit. Daytime temperatures today will
be in the low-mid 80s for most, with the nighttime temperatures
dropping into the 50s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 227 AM CDT Sat Jun 29 2024

Sunday into Monday, high pressure will dominate the area,
bringing below normal temperatures to the area. Current guidance
brings widespread mid-upper 70s throughout the area. Aside from
an increase in clouds on Monday, this will be a beautiful and
dry stretch of weather. The increase in clouds will be a result
of the moisture return needed ahead of the next system, which is
expected to bring showers/storms to the area.

Monday night and into Tuesday, we see our first wave that is set to
impact the area this coming week. Much of the action with this seems
to be late Monday night, moreso during Tuesday morning, as the LLJ
takes much of the night to shift east over our area. This action
will be associated with the leading shortwave trough, with the bulk
of the energy in our northern forecast area. Thus, this will be the
focus for higher precipitation amounts and thunderstorm
potential. Latest trends have been showing that showers/storms
may continue into the daytime hours, with some dry time in the
mix. There remains some uncertainty on this, but will continue
to update accordingly. It is too soon to discuss deterministic
amounts of rainfall, but we will see the potential for heavy
rain. Guidance continues to highlight the potential for high
moisture content once again, with PWATs near 2.00-2.50".
Ensemble guidance remains low on rainfall probabilities on the
first round of precipitation, with and increase to 40-60%
chances for at least an inch of rain with the second round on
Tuesday night into Wednesday, as the larger wave passes through.
This increase in precipitation will result from the increase in
moisture seen, as the highest moisture content is expected on
Tuesday into Wednesday. Localized areas of higher rainfall will
be possible, especially where storms are seen.

Beyond that, guidance starts to diverge on the next system, with
large differences in timing and placement. While guidance seems to
favor the Thursday night into Friday timeframe for more
precipitation, will opt to refrain from any more details, as there
is plenty of time for this to change. In either case, it would seem
that we will approach the end of the work week with multiple rounds
of showers and storms for the area. All guidance highlights much of
the end of the week and into the weekend as an active period for
rainfall. Unfortunately, all of this rainfall will lead to further
fluctuations on the projected flooding along area rivers. Be sure to
stay up to date on local flood headlines!

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 645 PM CDT Fri Jun 28 2024

Periods of MVFR/IFR are forecast tonight into early Saturday
morning, with the lowest ceilings at CID and DBQ. Isolated
showers and storms will remain possible into Saturday AM, but
confidence on direct impacts to the terminals is low. BRL may
have a slightly higher chance for scattered storms late tonight
into early Saturday AM, but with low confidence on where (or if)
this round of convection develops, left thunder mention out of
the TAFs for now.

&&

.HYDROLOGY...
Issued at 1213 PM CDT Fri Jun 28 2024

Headline Changes:

Issued a flood watch for the Wapsipinicon River near De Witt due
to recent rainfall and QPF in the next 24 hrs. Upgraded Illinois
City LD 16 on the Mississippi from Moderate to Major flood
category.

Discussion:

Higher rainfall fell in the Wapsipinicon River basin than
initially forecast. As a result, the new forecast for the De
Witt gage has the river reaching flood stage in a little over 24
hrs. However, confidence in the placement of QPF tonight
remains too low to issue a warning at this time. Later shifts
will monitor trends and can issue if needed. The Cedar River
forecasts remain on track, with crests likely in the next 24
hours at Palo and Cedar Rapids. A secondary rise with a lower
crest than the 1st one, is now forecast on the Cedar due to the
1-2 inches that fell near the headwaters in the past 24 hours.

On the mainstem Mississippi, rises will continue at all sites
over the next 7 days. Higher rainfall amounts in southern MN
and northern IA in the past 24 hours has resulted in a quicker
forecast to Major flooding for many sites by approx. 36 to 48
hrs earlier, including Rock Island LD 15. Crests along the river
should begin to show up in upcoming forecasts this weekend
beginning with Dubuque LD 11. Barring any more heavy rainfall,
crests are anticipated in the July 4th-10th timeframe.

&&

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

&&

$$

SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...Gunkel
HYDROLOGY...Gross