369
FXUS63 KDVN 092016
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
216 PM CST Sat Nov 9 2024

.KEY MESSAGES...

- A conveyor of showers continue to stream up acrs the area from
  the south into tonight as the atmospheric column saturates.
  Low chance for an isolated lightning flash in this
  environment. Activity shifting more to east of the MS RVR
  this evening.

- Sunday through Tuesday will largely remain dry, except for
  some isolated to scattered light showers north of I-80
  Sunday, along with breezy conditions.

- Another system brings additional rain chances on Wednesday.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 215 PM CST Sat Nov 9 2024

Tonight...Nearly stacked vertical cyclone seen wrapping up in an
occlusion process currently acrs the west central plains, with this
feature currently expected to slow-roll acrs north central IA by
Sunday morning. Mainly light showers will continue to move up acrs
the area, with a lot of initial moisture advection going into the
top-down saturation process. Rather strongly sheared column has no
instability or lapse rates worthy to support much thunder at all,
will keep out mention although can`t rule out and isolated flash.
The showers will become more numerous along and east of the MS RVR
through mid evening, before in-wrapping dry slot from the southwest
shunts them out of the area off to the east and northeast by
midnight. Like the previous shift mentioned, fcst soundings top-down
dry to classic drizzle profiles, and with continuing lift will keep
the drizzle mention going. Low cigs and boundary layer saturation
remains, so will add some ambient fog mention for a grungy night.
But low confidence if there will be any widespread dense especially
with southeast to southerly sfc winds maintaining overnight, may
just be the 1-3SM VSBY stuff. Warm front off occlusion will whirl
through the area, and with low clouds, higher sfc DPT feed and south
winds don`t see the temps dropping off that much overnight from
evening values. Total rainfall amounts by 12z Sunday still look to
range from 0.10 to 0.30 of an inch, most areas under a quarter inch.
A little better rainfall may fall in a swath tonight along and just
east of the DVN CWA following a better PWAT feed, where they may get
a quarter inch or more after 00z tonight.

Sunday...The occluding cyclone complex will migrate east-
northeastward acrs WI, with associated sfc trof front sweeping acrs
the CWA for a wind veer and increase to the west. Mixing profiles
suggest a breezy day with speeds of 15 to 25 MPH including most
gusts. Somewhat deeper mixing and some breaks in the clouds
especially south of I-80 will make for highs in the mid to upper
50s, with a 60 possible in the south. Wrap around sctrd to isolated
showers will look to develop and move acrs areas mainly north of I-
80, and especially Hwy 30. Interesting that fcst soundings show much
better lapse rates of 7 C/km and elevated instability along and just
north of the DVN CWA near the upper low center more favorable for
lightning than today. Will leave thunder mention out for now but may
be something to keep in mind for the Hwy 20 corridor through mid
Sunday afternoon.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 215 PM CST Sat Nov 9 2024

Monday and Tuesday...A fair weather period as both sfc high pressure
slides acrs the upper MS RVR Valley into the GRT LKS, and upper
ridging bulges it`s way eastward acrs the region from the west.
Seasonable to a bit above normal temp trends through Tuesday.

Wednesday...Active pattern will look to shuttle the next Pacific
trof inland and progress acrs the MS RVR Valley this day. Some
timing and handling details to be worked out with this progressive
wave, but it should have enough pre-system moisture advection to
utilize to kick up bands of showers that may move east acrs the area
with light to moderate rainfall amounts and maybe even a chance for
some thunder. Interesting that the latest 12z run deterministic ECMWF
splits the local area with more shower activity off to the north and
especially south of the CWA closer to respective forcing wings and
digging trof base.

Thursday and Friday...Another round of post-system upper and sfc
ridging for a dry end to the week. Moderating temp profiles with
some BL return flow orientation will lead to above normal temps
again for Thursday and especially Friday, when currently progged
thicknesses support highs in the low to mid 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1130 AM CST Sat Nov 9 2024

VFR conveyor of clouds and embedded light rain showers will
continue to stream up this way through the afternoon, with a
deterioration to MVFR as top-down saturation continues with a
southerly moisture feed. Brisk southeasterly sfc winds may gust
up to 20 KTs or more into the evening. As a warm front ahead of
a central plains storm system lifts northward through the area,
the sfc winds will veer to the south overnight and eventually
southwest by mid Sunday morning and become gusty again.
Overnight, the IFR or even some LIFR CIGs and VSBYs seen acrs
western MO ATTM, will make their way up acrs the area and linger
into the early Sunday morning hours. An in-sweep dry slot by
should bring about CIG and VSBY improvements from the southwest
as Sunday morning progresses and into the midday period.

&&

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

&&

$$

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