000
FXUS63 KDVN 150628
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
Issued by NWS Paducah, KY
130 AM CDT Mon Apr 15 2024

...06z Aviation Update...

.KEY MESSAGES...

- Well above normal temperatures can be expected through the
  middle of next week, with temperatures increasing into the
  upper 70s to 80s!

- Chance for strong to severe storms Monday night into Tuesday
  morning, as well as Tuesday afternoon and evening. All hazards
  will be possible.

- Cooldown expected after the Tuesday system, bringing us closer
  to seasonal norms. CPC favors below normal temperatures after
  the middle of next week.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 216 PM CDT Sun Apr 14 2024

Another beautiful day is being seen throughout, with temperatures in
the 80s! Once again, skies are mostly clear, but the winds have
gone down compared to yesterday. Cold front slowly passing
through our area now is shifting winds northerly behind it,
hovering around 5-10 mph. High pressure will settle in tonight
behind the front, where we will see light winds through the
night. Temperatures will be a bit cooler than last night, as
cold advection kicks in, with temperatures hovering around 50
for most.

Tomorrow, temperatures will drop a little compared to today, with
most in the mid-upper 70s. Although, that will still feel great with
a light southeasterly breeze. Winds will pick up through the day,
with gusts upwards to 20 mph. Also, as we approach late afternoon
and into the evening, we will start to see clouds approaching from
the south. These clouds will be a sign of change for the area, as
quite the change is expected over the next few days.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 216 PM CDT Sun Apr 14 2024

Big Picture...

Monday night, a deep upper trough will be situated over the western
Plains. This feature will be the guiding force for the weather to
come. Overnight, this wave pushes east, becoming negatively tilted
on it`s approach. Closer to the surface, we see surface cyclogenesis
during this timeframe, dragging a warm front north through our area.
A strong LLJ will be seen at 850 hPa, ranging between 30-50 KTs,
which will push east with the system as we approach Tuesday morning.
This will lead to a zone of LLVL convergence over our area,
especially in our south. This warm front will progress north through
the day on Tuesday, leaving our whole forecast area in the open warm
sector of the newly developed surface low. This low is expected to
track northeast through Iowa Tuesday, where the the cold front will
drag through the area Tuesday afternoon/evening, bringing along the
severe weather potential. Behind this system, LLVL northwesterly
flow kicks in, ushering cold/dry air into the area. While some weak
impulses work through the upper level flow, we are not expecting
many chances for precipitation beyond Tuesday.

Monday Night and Tuesday AM...

The first wave of showers and thunderstorms will push through during
this timeframe, in response to an increase in warm advection and an
advancing warm front through the area. Strong convergence along the
boundary will allow for thunderstorms to erupt Monday night. Timing
of the warm front has slowed down a bit, with it approaching our
south a little before midnight. We can see showers and storms
develop between 9pm to midnight, but the best chance for stronger
storms will be after midnight. As we progress through the night,
convective coverage will increase. Overall, instability is lower,
generally hovering between 500-1000 J/kg. Guidance differs greatly
on the CAPE axis and where/when that will be in our area. Shear
and lapse rates will be more than sufficient to favor a few
elevated strong to severe thunderstorms. As is usually the case
with nocturnal thunderstorms, we will likely be dealing with
hail potential and frequent lightning. This threat will continue
into Tuesday morning, with guidance diverging when it come to
timing of the exit of these showers/storms. This timing will be
important, especially when it comes to the next round of storms.

The SPC continues to highlight areas along/south of a line from
Belle Plaine IA to Macomb IL in a Marginal Risk for severe weather,
level 1/5. Again, main hazards will be large hail and lightning.

Tuesday PM...

Later in the day Tuesday, our forecast area will fall under the warm
sector of the advancing surface low. In the warm sector, we should
see moderate instability build, given nocturnal convection and cloud
debris move out in the morning. Although, there will be plenty of
forcing from this system that we are still expecting severe weather
potential, even with lingering AM showers/storms. Given moderate-
high shear, steep lapse rates, and sufficient instability, organized
convection is favored. Currently, guidance is showing the chance to
get a line of severe storms, with the environment favoring some
embedded supercell structures. Some leading supercells are possible,
but confidence is low on this. Confidence is higher on the arcing
line of convection Tuesday evening. The timing is Tuesday afternoon
and evening. Over the next 24, we will have a whole suite of new
guidance to help us better figure out which areas have the best
chance to get severe weather.

The SPC continues to highlight our whole area in a Slight Risk for
severe weather (level 2/5), with the addition of an Enhanced Risk
(level 3/5) for areas along/south of a line from Belle Plaine IA to
Macomb IL. All hazards will be on the table, but the primary hazards
will be damaging winds and a few tornadoes.

Event Rainfall...

Heavy rainfall can be expected with any storms that push through,
especially though the morning/afternoon on Tuesday. PWATS will range
between 1.25-1.50"+, which is well above the daily max locally.
Diving into probabilities, areas along and north of Interstate 80
have a 90-100% chance of seeing at least 0.50" of rain, with the
chances for 1.00" or more ranging between 70-90%. These
probabilities have trended upwards over the last 24 hours, but we
still remain between a 0-10% chance for 2.00" or more. While we are
not saying that it isn`t possible to see amounts that high,
widespread amounts of 2.00"or more are not expected. While the
totals that we have been advertising the last few days haven`t
changed much, there is still time for this to change a little.
Although, it is seeming that a widespread 1.00-1.50" is
increasingly likely, with areas along/south of Highway 34 seeing
between 0.75-1.00". This heavy rainfall will be widespread and
may lead to rises in local streams, as some are already higher
than normal. We also have a Marginal Risk for Excessive
Rainfall, which indicates the potential for localized flash
flooding.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 130 AM CDT Mon Apr 16 2024

VFR conditions are expected through the TAF period. Today will be
our final day in a stretch of very quiet conditions before a warm
front lifts through the area late tonight into Tuesday morning,
bringing inreasing chances of showers and thunderstorms. Northerly
winds at the start of the forecast period will gradually turn more
form the east by late this morning thorugh the afternoon. Stronger
east winds are expected to develop this evening, wiht gusts 20-
25kts.

&&

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

&&

$$

SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...12