Marion, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

088
FXUS63 KDVN 301735
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1235 PM CDT Sun Mar 30 2025

.KEY MESSAGES...

- Chances of showers and at least a few thunderstorms, some of
  which could become strong to severe, will be possible this
  morning, mainly across our southeast.

- Quiet conditions return for Monday through at least the first
  half of Tuesday before a large storm system moves in mid-
  week, with some additional chances of strong to severe storms
  late Tuesday night through Wednesday

- Temperatures start off on a cooler note but slowly rise back
  to the 70s by Wednesday

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 426 AM CDT Sun Mar 30 2025

A complicated weather event is on tap for this morning across the
area as an area of low pressure, currently situated over central
Iowa, approaches the area. A few mid-level impulses appear to be
embedded within the main upper-level trough that will continue to
become more negatively-tilted with time this morning. The first wave
just exited the area early this morning, which brought a line of
convection over our northwestern CWA. These storms did have some 1"
hail reports with them in central Iowa. However, only some small
hail was reported near Blairstown in southern Benton county, likely
owing to a diminishing trend in mixed-layer CAPE and increasing
convective inhibition per the SPC mesoanalysis guidance. A secondary
impulse, which is currently located near Kansas City, Missouri, is
progged to lift northeastward over our southeastern CWA after
sunrise this morning. CAM guidance remains in decent agreement on
the timing of the associated convection, which is between 12z-16z (7
AM to 11 AM). Also, CAMs indicate an MCV-type of appearance with the
convection. This area should have extra kinematic support due to a
southwesterly 35-45 knot low-level jet and increasing deep-layer
shear. Instability appears to remain pretty limited, with mixed-
layer CAPE values only around 500 J/kg over our southeast. Given
this more marginal setup, thinking that perhaps some small hail and
some gusts up to around 50 mph are possible with this activity, but
seems that the threat for strong to severe storms has decreased, and
as such, the new Day 1 convective outlook from SPC has only kept a
Marginal Risk (level 1 of 5) for our far eastern areas (the previous
Slight Risk has been pulled farther east and is out of our CWA
entirely).

Once the morning convection is over, the surface low should be north
of our CWA, with cold air advection (CAA) increasing in our area.
Temperatures today will be a forecasting challenge as they won`t
follow a typical diurnal curve, meaning temperatures will probably
be their warmest this morning, gradually cooling into the afternoon
as the cold front crashes through. The CAA should help enhance
momentum transport via steep low-level lapse rates and lead to gusty
conditions this afternoon and evening, gusting to 20 to 30 mph.
Expect a pretty brisk night tonight, thanks to the cooler air and
continued gusty conditions, with lows tonight falling to the upper
20s northwest to the lower 30s southeast. Wind chills will likely
fall to the upper teens to lower/middle 20s, so it will feel quite
chilly compared to the last few days.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 426 AM CDT Sun Mar 30 2025

The work week will start off on a quiet note, thanks to a large area
of high pressure that will translate over the north-central CONUS.
We should see more seasonal temperatures, as well, with highs in the
upper 40s to lower 50s. The quiet, dry conditions should linger at
least through Tuesday morning, if not the afternoon.

Attention then turns to an active period Tuesday night through
Wednesday as a longwave upper-level trough develops over the western
CONUS. A 130+ kt upper-level jet is progged to nose into Midwest
Tuesday night, becoming more negatively-tilted with time. LREF
cluster analysis from the GEFS, EPS, and GEFS ensembles do show some
uncertainty on just how amplified this trough will become, although
there is a bit more consensus from 24 hours ago. The full suite of
deterministic and ensemble guidance indicates a Colorado Low
developing via lee cyclogenesis and translating northeastward toward
the Upper Midwest. Both the GEFS and EPS ensembles show this general
path, but uncertainty remains on the exact path of the surface low.
The latest ECMWF standardized anomalies indicate a pretty potent
MSLP, with values between 2 to 3 standard deviations below the mean.
Widespread showers and storms are expected with this system Tuesday
night into Wednesday morning (80-100% chances), with some of these
storms possibly strong to severe as a warm front lifts northward. A
very stout 50-60+ kt low-level jet ahead of the surface low is
progged to develop, aiding in poleward theta-e transport. Mid-level
lapse rates don`t appear to be too steep - generally around 6.5 to
7.5 degree C/km, but given that convection should mainly be
elevated, hail will likely be the main threat. The ECMWF EFI CAPE-
Shear values now range between 0.7 to 0.9, indicating a notable
severe weather environment, and SPC now has nearly our entire region
in a Slight Risk (level 2 of 5) for severe weather Tuesday night,
and a Slight Risk for most of the area for Wednesday and even an
Enhanced Risk (level 3 of 5) just grazing our southeast! Definitely
something to keep an eye on as we approach mid-week. High
temperatures will likely warm back up to the upper 60s to
lower/middle 70s per the NBM on Wednesday.

For Thursday through Saturday, we are looking at generally dry
conditions, except for perhaps some light showers possible Friday
night through Saturday morning. After a warm Wednesday, temperatures
should return to more seasonal values for Thursday through
Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1232 PM CDT Sun Mar 30 2025

SHRA/TSRA developing I-55 east of the Mississippi will move
east through 00z/31. Patchy SHRA across eastern Iowa will
persist through 00z/31 with a RA/SN mix developing along the
highway 20 corridor 00z/31 to 06z/31 as winds veer to the
northwest. After 12z/31 conditions will improve to VFR across
eastern Iowa and northern Illinois.

&&

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

&&

$$

SHORT TERM...Schultz
LONG TERM...Schultz
AVIATION...08