610
FXUS63 KDVN 271629
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1129 AM CDT Mon May 27 2024

.KEY MESSAGES...

- Isolated to scattered thunderstorms possible this afternoon.
  There is a marginal or level 1 out of 5 risk of severe
  thunderstorms this afternoon.

- Quiet weather is forecast for Wednesday and Thursday with high
  temperatures ranging from 70 to 75 degrees.

- Chances of showers and storms return Friday through Sunday.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 229 AM CDT Mon May 27 2024

At 2 AM a cold front sits to our south across northern Missouri
with a second cold to our northwest across northern Minnesota
and North Dakota. Low clouds across the area are slowly sliding
to to our east. A northwest breeze has continued across the
area overnight with speeds of 10 to 20 MPH. Temperatures across
the area range from 55 degrees at CID to 60 degrees at Moline.

A vort max is evident on water vapor imagery early this morning
moving into the central Dakotas and is forecast to arrive later
this afternoon into this evening as the Upper Midwest remains
on the western edge of a trough over eastern Canadian and the
northeastern US. This will also drive a cool front across the
area. Temperatures ahead of the front are forecast to be in the
mid 70s with dewpoints in the mid 50s. Despite the drier airmass
most unstable CAPE values of 500 to 1000 J/KG are possible with
30 knots of 0 tp 6 km shear. CAMs are showing the potential for
damaging winds. Given the drier atmosphere, expected isolated
to scattered coverage for storms today. For this reason, the
storm prediction center has much of the area under a marginal
risk of severe storms.

Showers and thunderstorms will end from west to east this
evening with clouds lingering across the area north of
Interstate 80. Low temperatures on Tuesday morning will range 50
to 55 degrees.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 229 AM CDT Mon May 27 2024

The long term period begins on Tuesday morning with deep
northwest flow aloft as we continue to sit on the edge of a
deep trough to our east. This will allow another disturbance to
move across the area during the day on Tuesday with scattered
showers and storms possible once again.

Wednesday through Friday morning a ridge of high pressure will
move across the area bringing quiet weather to the area.
Temperatures will be pleasant and range from 70 to 75 degrees.

Temperatures will warm Friday through Sunday as high pressure
moves to the east with highs in the upper 70s to lower 80s by
Sunday. A closed 500 MB low is forecast to move across the
southern Canadian Plains late this week into next weekend and
bring several chances for showers and storms with the best
chances (25 to 35%) on Saturday. Dewpoints will remain in the
50s during this period so instability will be somewhat limited.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 625 AM CDT Mon May 27 2024

MVFR ceilings have moved to the east of all TAF sites this
morning. Another storm system will move across the area this
afternoon into the early evening with isolated to scattered
showers and storms possible. If showers do occur then MVFR
ceilings and visibilities are possible. Decided to continue to
use of a prob30s to account for KCID, KDBQ, and KMLI. Expect
gusty northwest winds to continue through the day at all TAF
sites before winds lower to 5 to 10 knots this evening. Outside
of showers and thunderstorms, expect VFR conditions to occur.

&&

.HYDROLOGY...
Issued at 1110 AM CDT Mon May 27 2024

Rainfall the past 24 hours was not as widespread as two days
ago. Although not as heavy, amounts of 0.5 to 1 inch fell
across northeast Iowa and parts of Wisconsin and Illinois.

River forecasts have not changed all that much. Crests are
working down the tributary rivers of eastern Iowa with new
crests working down the tributaries of northern Illinois.

The flood watches continues for the Skunk River at Augusta, IA
and the Mississippi River at New Boston. Attenuation of the
flood crest on the Skunk River brings a lower confidence that
flood stage will be achieved at Augusta, Iowa.

On the Mississippi, the forecast rise at New Boston is due to a
combination of routed flow and the expected Cedar/Iowa flow
arriving immediately downstream. The Cedar/Iowa flow will result
in backwater effects but there is still some uncertainty
regarding the timing of this flow. If the Cedar/Iowa flow and
Mississippi routed flow constructively interfere with each
other, that is arrive at the same time, then the probability of
New Boston achieving flood stage is much higher. If
deconstructive interference occurs, that is the flows arrive at
different times, the the probability of New Boston reaching
flood stage would be lower. Right now the probabilities of New
Boston reaching flood stage are about 45-50 percent.

After a brief reprieve this week, the active weather pattern
will resume next weekend and into the following week. The
Climate Prediction Center has a 35-38 percent probability
favoring above normal precipitation into the first week of June.

&&

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

&&

$$

SHORT TERM...Cousins
LONG TERM...Cousins
AVIATION...Cousins
HYDROLOGY...08