Dubuque, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

614
FXUS63 KDVN 231108
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
508 AM CST Sat Nov 23 2024

...Updated for 12z Aviation...

.KEY MESSAGES...

- Temperatures briefly going above normal on Sunday, the
  warmest day for the foreseeable future.

- One or more systems will be moving through the Midwest during
  the holiday period (mid week into next weekend). Considerable
  uncertainty exists regarding the track and potential for any
  impacts to the area.

- The pattern change that occurred last week will remain active
  through early December. The temperature probability of well
  below normal temperatures is 70-80%. There is no clear signal
  that favors above or below normal precipitation into early
  December. However, the probability for snow is increased due
  to the colder than normal temperatures.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 245 AM CST Sat Nov 23 2024

Low stratus continues to blanket much of the area early this
morning trapped beneath a subsidence inversion. Pockets of fog
are also occurring across portions of eastern Iowa, mainly
west of a Manchester to Washington line, which is in closer
proximity to the surface ridge axis, light wind and back edge of
the stratus.

The evolution of the low clouds today will play a critical role
in our high temperatures. As we saw yesterday, where the stratus
remains locked in highs will be limited to the upper 30s to
around 40. My feeling is with the 925 hPa ridge building to
roughly the Mississippi River by late PM, much of the area may
hang onto the stratus with the lingering subsidence inversion,
as generally depicted by the HRRR, NAMNest and RAP models. The
exception may be in areas well west/south of the Quad Cities or
roughly across SE Iowa, NE Missouri and possibly portions of WC
Illinois where the low level flow is shown to turn more
anticyclonic this afternoon that may aid in chewing away at the
stratus. However, atop we`ll also see plenty of higher level
clouds. But, enough sun peaks potentially to push highs in the
mid to possibly even upper 40s for areas where the low clouds
decrease.

There is a weak wave progged to shift SE passing mostly to our
north today. This will help induce weak frontogenetical forcing
as it traverses along an elevated baroclinic zone. Can`t totally
rule out a few sprinkles or flurries for mainly parts of far
NW Illinois via seeder-feeder mechanism, but the better forcing
and potential saturation is suggested further north into Wisconsin
thus I have left out mention for now.

For tonight, anticipate trends toward decreasing stratus continuing
for the northeast half or so of the service area although we`ll
continue to see higher level cloudiness streaming in. The result
is overall partly to mostly cloudy skies. The departing ridge
and strengthening southerly surface to 925 hPa southerly flow/
warm advection will likely foster steady to even warming temperatures
through the 30s by late evening and overnight.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 245 AM CST Sat Nov 23 2024

Sunday looks to be the warmest day for the foreseeable future,
as southerly winds (gusty at times in the morning) and
attendant warm advection ahead of an approaching low foster
highs climbing into the 50s and possibly even a few lower 60s
south. This despite partly sunny to mostly cloudy skies, and
attributed purely to advection. Low level moisture looks to be
shallow, and so any precipitation would likely be mainly trace
amounts of sprinkles or drizzle ahead of the low and cold front.

The cold front departs early Monday morning. A tightening
pressure gradient and cold advection will foster brisk/windy
conditions with temperatures likely falling into the 30s for
many areas by midday then holding nearly steady in the
afternoon. Precipitation potential looks low Monday and mainly
a few flurries if anything with the cold advection as it looks
right now. However, with the mid level baroclinic zone nearby
we`ll want to keep an eye out for any wave traversing this
thermal gradient that could foster some chances for light snow.

Tuesday looks to be quiet and chilly with below normal highs
mostly in the 30s, as surface to mid level ridging dominates.

The focus then shifts to Wednesday into Thanksgiving as three
of the four clusters of the 500 hPa height pattern support
broad troughing across the region. Broadscale lift/forcing will
support chances for precipitation, with snow being favored as
the dominant precipitation type based on thermal parameters.
Chances for impactful snow look low at this time with NBM
and LREF probabilities for 0.10 inch or more of liquid falling
as snow only at around 20-40 percent, highest in our far southern
service area. The 00z ECMWF Extreme Forecast Index (EFI) is not
suggesting any anomalous or extreme event potential either with
this system with no EFI and very low Shift of Tails (SoT).
Despite this it still bears close monitoring being a busy
holiday travel period, and the fact that this system is still
quite a few days out to where we could expect to see changes in
the intensity and track. Stay tuned!

Beyond, confidence remains high on turning much colder and well
below normal at the end of November and beginning of December.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 505 AM CST Sat Nov 23 2024

IFR to LIFR conditions in low clouds with patchy IFR to MVFR
visibility in BR will begin the period. Much of the guidance
supports an eventual improvement to VFR at the terminals. The
timing of this improvement, however remains quite challenging.
Low level ridging builds along the Mississippi River by late
PM. I anticipate the subsidence inversion to keep the low
clouds trapped at DBQ and MLI for today and predominantly IFR
with some low MVFR possible later this afternoon. Meanwhile, as
the flow turns more anticyclonic this afternoon out west this
may allow for a clearing trend to ensue, initially at BRL
18z-21z and then CID 20-23z based on a general consensus of
HRRR, NAM and RAP guidance cloud cover products. This decrease
in stratus and improvement to VFR will be shown to occur this
evening/tonight at MLI (00z-03z) and DBQ (03-06z). But, there
is lower confidence overall as lower CIGs could remain
entrenched longer and/or expand this evening ahead of a warm
front.

&&

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

&&

$$

SHORT TERM...05
LONG TERM...05
AVIATION...05