779
FXUS63 KDVN 242310
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
610 PM CDT Sun Sep 24 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 304 PM CDT Sun Sep 24 2017

Another unseasonably hot day with temperatures under a mostly sunny
sky in the upper 80s to around 90 degrees at 2 PM CDT. This is a couple
of degrees cooler than yesterday. An impressive and strong cool front
is near the western Iowa border with temperatures in plains under clouds
in the 50s. Upstream energy shows the slow progression of this system
the next couple of days arriving by late Tuesday, if not earlier.

&&

.SHORT TERM...(This Evening through Monday)
ISSUED AT 304 PM CDT Sun Sep 24 2017

Short term forecast confidence assessment...good or above average with
persistence a key player supporting temperatures with no significant
sensible weather issues for highs/lows within 3 degrees of forecast.

Tonight...mostly clear and mild with mins mostly within a degree or
two of last night which supports lower 60s with some mid 60s in favored
milder locations. Persistence suggest later shift may be able to lower
mins a degree or two this evening. South winds 5 to 10 mph.

Monday...Another very warm day with highs a degree or two lower than
today or mostly upper 80s which should be just short of record highs.
Heat indices should stay mostly below 90 degrees with slightly drier
air as well. Clouds may arrive far west with trends suggesting low
POPS of showers and isolated storm after mid day likely too fast. South
winds of 5 to 15 mph expected. Trends suggest highs may be a degree
or two some to most locations too warm for later shifts.

.LONG TERM...(Monday Night through Sunday)
ISSUED AT 304 PM CDT Sun Sep 24 2017

Below normal temperatures expected the second half of the week and
through the weekend.

There are still questions regarding the arrival of precipitation
with the next front. Like yesterday, the forcing is behind the front
with little if any forcing ahead of the front. Thus a majority of
the precipitation should occur behind the front. Also, the forcing
gets weaker as the front moves into eastern Iowa. These factors
raises questions regarding the areal coverage and amount of
precipitation with the frontal passage.

Right now the model consensus has slight chance to chance pops for
areas west of the Mississippi Monday night with slight chance to
chance pops across the entire area on Tuesday.

The possibility exists that most if not all of the area could remain
dry Monday night with the rain slowly moving into the area on
Tuesday. Highs on Tuesday ahead of the front will be above normal.

Tuesday night the model consensus has slight chance pops during the
evening in the far east for any lingering precipitation behind the
front.

On Wednesday dry and cooler conditions will be seen as high pressure
builds into the Midwest. Temperatures are expected to be below
normal.

Wednesday night on...

The model consensus has mainly dry conditions Wednesday night
through Sunday with below normal temperatures.

However, a strong upper level low will be dropping into the Great
Lakes Thursday night through Saturday. Disturbances rotating around
the low combined with cold air aloft may allow diurnal rain showers
to develop during the afternoon and evening of Thursday and Friday.
If this occurs, then the northeast third of the area would have a
low risk of rain.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
ISSUED AT 610 PM CDT Sun Sep 24 2017

VFR conditions will prevail tonight into Monday as high pressure
over the area slowly retreats eastward. Scattered thunderstorms
are expected Monday afternoon ahead of a cold front moving into
western Iowa. These storms are expected to remain west of the
terminals through the afternoon. With only a low chance for
isolated storms in eastern Iowa, thunderstorms are not mentioned
in the terminal forecasts.

&&

.CLIMATE...
ISSUED AT 304 PM CDT Sun Sep 24 2017

Record Highs for September 25...

Moline.........91 in 1920
Cedar Rapids...93 in 1920
Dubuque........90 in 1920
Burlington.....92 in 1999

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...Nichols
SHORT TERM...Nichols
LONG TERM...08
AVIATION...Sheets
CLIMATE...Nichols