Area Forecast Discussion Issued by NWS Quad Cities, IA IL
000
FXUS63 KDVN 102249
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
549 PM CDT Wed Apr 10 2024
...00z Aviation Update...
.KEY MESSAGES...
- Rain chances increase tonight into Thursday, with
thunderstorms possible on Thursday. Highest precipitation
amounts are expected primarily east of the Mississippi River
Valley near 0.1" with bands near 0.25" possible.
- A warming trend is expected into the weekend with above normal
temperatures forecast to stick around through much of the
period.
- Will be watching another system forecast to bring shower and
storm chances to the area early next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 245 PM CDT Wed Apr 10 2024
A northern and southern stream of synoptic forcing seen on upper
level water vapor imagery early this afternoon are driving
precipitation in the Northern Plains and Central Plains,
respectively. Scattered reflectivity in the Northern Plains is tied
to a southeasterly digging open wave and associated surface low over
the Red River Valley, with accompanying frontal boundary draped
southwest through the Dakotas. Meanwhile, southwest to northeast
reflectivity bands from the Central Plains through southern Illinois
are associated with a well phased previously closed upper level low
seen rejoining upper level flow through the Southern Plains.
Associated surface low has been progressing through the Lower
Mississippi River Valley early this afternoon with accompanying
moisture boundary bifurcating Missouri southwest to northeast into
the Wabash River Valley.
A slight southeastern shift in the surface low track has also
shifted initial precipitation chances this evening to the local
southern periphery; Scotland County, MO to Bureau County, IL.
Slightly later onset can be attributed to low level dry air locally
with surface dewpoint depressions of 30+ degrees in McDonough
County, IL. While the pressure saddle between the aforementioned
surface lows is providing a shrinking/stretching axis across the
southern half of the forecast area, a widespread lack of moisture is
decreasing confidence in northwestern extent of precipitation. While
high resolution models picked up on this sharp cutoff in
precipitation early this morning, National Blend was adamant until
most recent runs. Therefore, have blended high resolution and
National Blend guidance to account the shift and align with southern
neighbors better.
Higher precipitation chances fill in Thursday morning as a narrow
filament of moisture along the aforementioned shrinking axis align
with positive mid level vorticity advection. The synoptic low shifts
north-northeast through Thursday as trough phases even further.
Primary precipitation chances remain east of the Mississippi River
Valley in Illinois as the low shifts north through Michigan`s mitt.
Mid level deformation and low level cold air advection provides
forcing and steepened low level lapse rates. As a result, slight
instability builds up to 500 J/kg ML/MU CAPE. Therefore, thunder
chances increase Thursday afternoon-evening. Unidirectional flow
limits overall shear until Thursday evening with eventual frontal
passage. Prefrontal forcing and associated instability expected to
keep storms ahead of any increased shear, with mid level deformation
resulting in near 40 kts at 0-6km and less than 5 kts from 0 to 3km.
Given the very limited instability, realizing any of this shear will
be limited confidence and timing. Can`t rule out any small hail
given forecast skew Ts within a minuscule hail growth zone at times.
Overall precipitation amounts are expected primarily east of the
Mississippi River Valley near 0.1" with bands near 0.25"
possible where afternoon storms frequent.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 245 PM CDT Wed Apr 10 2024
As the system continues to depart a tight pressure gradient
will keep breezy winds into the day on Friday before easing some
Friday night. Upper level ridging is forecast to build into the
Plains (flattening into the weekend). A warming trend is still
expected into the weekend with increasing warm air advection and
winds turning more southerly. Highs climb into the 70s on
Saturday and by Sunday NAEFS suggests 850 mb temperatures in the
90-97.5th percentiles of climatology with highs at the surface
forecast in the upper 70s to low 80s. Above normal temperatures
look to continue into the early start of the week, though
temperature spread among ensemble guidance does begin to
increase quite a bit heading further into the period.
Model guidance has continued to show an upper level low moving into
the Plains on Monday, developing a strong surface low that generally
tracks northeastward across the region. Ensemble solutions highlight
a stronger signal for showers and storms across the area during this
time period. There still remain some differences in details such as
timing and storm track, resulting in lower confidence in impacts at
this time. However, it will be a timeframe to monitor for the
potential of strong to severe storms. Still plenty of time this far
out, so be sure to stay up to date on the latest forecast as details
are refined in the coming days.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 543 PM CDT Wed Apr 10 2024
VFR conditions will prevail throughout the TAF period. There is
potential of a high-end MVFR deck impacting KMLI/KBRL/KDBQ late
in the period with a low to medium chance of rain showers
(20-50%), but given these are low confidence I did not include
mention in the TAFs.
Light and variable winds to start the period will increase out
of the northwest as a surface low strengthens over the lower
Mississippi River Valley Thursday. Gusts around 25-30 kts will
be possible by Thursday afternoon.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...ARX
LONG TERM...ARX
AVIATION...Speck