Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 120549
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1249 AM CDT Tue Mar 12 2024

.KEY MESSAGES...

- Warm through mid-week with breezy winds leading to very high
  fire danger

- Shower and storm chances arrive Tuesday night and become more
  widespread Wednesday night into Thursday

- Cooler air with below normal temperatures arrive for the
  weekend into early next week

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 207 PM CDT Mon Mar 11 2024

A beautiful afternoon was unfolding across all of eastern Iowa,
northwest Illinois and far northeast Missouri. Skies featured
plentiful sunshine, with a bit of a breeze noted out of the
southwest. 18z surface analysis showed high pressure centered
across Tennessee, with a weak low pressure over the Dakotas.
Temperatures as of 200 PM ranged from the mid 60s to low 70s.

For the rest of the daytime, look for continued breezy
conditions and pleasant temperatures as highs climb into the
upper 60s to mid 70s. See the climate section as DBQ will be on
the fence with tying or breaking their record high. Winds will
gust around 25-30 MPH as we mix down dry air and a 40-50 kt low
level jet. These winds, dry air, and warm temperatures will
lead to a very high fire danger area-wide into this evening.

For the remainder of the short term, our primary weather
concern will be temperatures and winds. The high pressure to our
southeast will be very slow to shift in position, resulting in
quiet weather conditions through Tuesday. Winds will remain
breezy thanks to a tight surface pressure gradient between the
high and an approaching front, with gusts during the daytime
approaching 30 MPH. These winds will continue to advect warmth
and moisture into the area, with Tuesday seeing temperatures
very similar to today. Look for lows tonight in the mid 40s,
with highs Tuesday in the upper 60s to low 70s. Increasing
clouds due to increasing moisture will be seen.

Late Tuesday afternoon, will be keeping a close eye on
southeast Iowa, west central Illinois and northeast Missouri
where an approaching shortwave will increase chances of showers
and thunderstorms. Much of this chance will be occurring in the
long term period.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 207 PM CDT Mon Mar 11 2024

Tuesday Evening and Overnight...

An approaching shortwave and surface frontal boundary will be the
focus area for potential development of showers and thunderstorms
Tuesday evening and overnight. Latest CAMs zero in on southeast
Iowa, west central Illinois and northeast Missouri along and east of
the Mississippi River for the highest chances (30-50%), as this
area is likely to have the best moisture return ahead of the
boundary. That being said, the moisture levels themselves are
not overly impressive with dewpoints projected to only climb
into the 40s to near 50. This may make coverage more scattered
and tied to the boundary. With little vertical shear for
organization, the risk for any severe weather is low.

Wednesday through Friday...

Most of Wednesday will be dry and warm with continued highs in
the 70s. This will change by the evening with increasing chances
of showers and storms. Synoptically, a strong trough across the
western CONUS will eject a shortwave across the central Plains
into the Midwest Wednesday night. Concurrently, a 100 kt jet
streak is forecast to develop above this shortwave as the
pressure gradient aloft tightens. This, along with strengthening
CVA with the shortwave, will promote development of a closed
surface low across southeast Colorado Wednesday morning. The
surface low is forecast to track northeast along the 850 hPa
front, and will move directly overhead daytime Thursday.

Increasing moisture from southerly flow and lift from the
jet/surface low will lead to a high probability (60-80%) of a
widespread soaking rain for Thursday. Thunderstorms are also
possible, especially Wednesday evening and night, thanks to added
low-level convergence from a developing LLJ. Will have to keep a
close eye on this, as increasing winds aloft and steepening lapse
rates could support some potential for storms capable of producing
large hail. Much of the threat at this time is focused in
northern Missouri, where the Storm Prediction Center has a Level
1 (marginal risk) of severe thunderstorms for the period.
However, this is likely to change as guidance gets a better
handle on timing and placement of moisture and the best lift.

Heading into Thursday, unsettled weather with overcast skies, rain
showers and cooling temperatures is expected as the surface low
moves overhead. It will be breezy as well as the surface low deepens
and tightens the pressure gradient. Rainfall amounts should prove
beneficial with the majority of guidance suggesting amounts of
around 0.50-1.00".

By the end of the work week, zonal flow will return briefly before a
strong cold front arrives for Saturday. Precip should be lacking
with the front given low amounts of availible moisture, but much
cooler temperatures will advect into the area thanks to strong
northwest winds. Our above normal pattern looks to shift to
below normal for a change, with latest ensembles projecting
highs in the low 40s by early next week with 850 hPa temps
plunging near to below -10 celcius.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1245 AM CDT Tue Mar 12 2024

The primary aviation forecast points are low-level wind shear
(LLWS) early this morning and potential for scattered storms
for later tonight.

A 40-45 kt southwesterly low-level jet in the 1,000-2,500 ft
layer will persist through 13Z-14Z across the area, resulting in
probable low-level wind shear given only 9-12 kt of surface
flow. Mixing will ensue again today, with southwesterly surface
gusts of 20-25 kt with high confidence, and any higher should be
sporadic. Wind speeds will begin diminishing mid-afternoon as
the pressure gradient eases, with a quick drop off near sunset.

For tonight, a quick-moving weather disturbance will traverse
the Iowa/Missouri border into northern Illinois. The signal is
fairly good for scattered showers and isolated storms from this
and within the region this looks to be between 03Z and 11Z.
Confidence is highest in these south of I-80, especially with any
prior to 06Z, but will have to monitor for the chance up to MLI
overnight.

&&

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

&&

$$

SHORT TERM...Speck
LONG TERM...Speck
AVIATION...Friedlein


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