Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 070457
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1057 PM CST Sat Mar 6 2021

...06Z AVIATION UPDATE...

.SYNOPSIS...
Issued at 249 PM CST Sat Mar 6 2021

High pressure over WI and IL stretching SW back into TX provided the
area with plenty of strong March sunshine and relatively light
winds. As of 1 PM, there was a wide range in temperatures based on
snow pack.  Areas north of I 80 where snow pack remains were in the
upper 30s and 40s, while to the south where there is no snow
temperatures were in the low to mid 50s. The cold spot was Freeport
with a reading of only 37. Dew point temps were in the 20s to mid
30s.

&&

.SHORT TERM...(This Evening through Sunday)
ISSUED AT 249 PM CST Sat Mar 6 2021

Tonight, high pressure will drift eastward as a warm front moves
into southwest IA. Skies will be mostly clear and winds will be
nearly calm.  This will allow temperatures to fall into the upper
teens to low 20s in NW IL, to the low to mid 30s in southeast IA,
northeast MO, and west central IL.

Sunday, mild temperatures and increasing southerly winds will be
seen as the warm front works into the area.  There is considerable
uncertainty in the temperature forecast, which could be off by
several degrees in places. Southern portions may get warmer than
forecast, while NW IL areas that still have snow on the ground may
be too warm in places and NW portions of the CWA may be too cold and
mixing and sunshine may overcome the snow pack hindrance. The
current forecast has upper 40s and lower 50s north of Highway 30,
mid 50s to low 60s along I 80, and mid and upper 60s further south.
Regardless, it should be a pretty nice spring-like day with some
sunshine and plenty of melting snow for areas north of I-80.

.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 249 PM CST Sat Mar 6 2021

Monday and Tuesday

The storm track early in the week will set up across the Northern
Plains and south-central Canada, which locally will lead to
persistent southerly winds, low-level warm air advection, and
increasing near surface moisture (dewpoints well into the 40s
Tuesday).

Well above normal temperatures are expected with highs in the 60s
for most of the area. 50s may hold on north of highway 30 on
Monday, but even these areas should be close to 60 F by Tuesday as
the remaining snowpack melts away.

Wednesday

Windy and very warm conditions are anticipated in the warm sector
of a low tracking through north-central Iowa into western
Wisconsin. For highs, have mid-upper 60s central/south and low
60s in the north. This is slightly above the NBM 50th percentile.
Forecast soundings indicate the potential for wind gusts over 40
mph, so may have to increase gusts in later forecast updates if
confidence increases.

SSW low-level jet ramps up on Wednesday across the Upper Mississippi
Valley, reaching 50-60 kts at 850mb. These impressive kinematics
will lead to strong moisture and warm air advection through the
day and a chance for scattered showers and isolated elevated
thunderstorms. GFS/ECMWF have at least a few hundred J/kg of
MUCAPE spreading in from west to east during the afternoon and
evening.

A cold front will arrive Wednesday night bringing with it a chance
for scattered showers and possibly a few thunderstorms. Widespread
heavy rain is not anticipated at this time through Wednesday
night.

Thursday On

Model consensus is for the cold front to work through the southern
forecast area Thursday morning, taking the threat for heavy
rainfall into northern Missouri and central Illinois. The GFS is
an outlier transitioning the front to a quasi-stationary boundary
over the southern CWA. If this latter scenario panned out (which
is low confidence at this lead time), bouts of heavy rain would
impact our southern counties.

Cooler weather is forecast for the end of the week with highs in
the upper 40s to low 50s on average. Low chances for precipitation
extend into Saturday, mainly to account for the wetter GFS. The
EC and CMC, being more progressive with the cold front, are mostly
dry during this time. Uttech

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
ISSUED AT 1057 PM CST Sat Mar 6 2021

High pressure will provide VFR conditions overnight into Sunday
morning with light winds and clear skies. Mostly light east to
southeast winds will become southerly around 10 to 15 kts by late
Sunday morning.

&&

.HYDROLOGY...
Issued at 1130 AM CST Sat Mar 6 2021

Rivers across eastern Iowa, northern Illinois and far northeast
Missouri continue to show mainly minor within bank rises with a few
sites having moderate within bank rises from the snowmelt. The
majority of sites are expected to remain well below flood stage.

The Wapsipinicon River near Dewitt is forecast to approach the minor
flood stage Wednesday and Thursday.

The Pecatonica River at Freeport as well as the Rock River near
Joslin and at Moline are all forecast to rise to within a foot of
their respective minor flood stages Wednesday through Friday.

Warmer temperatures this weekend and into early next will promote a
more vigorous snowmelt north of Highway 30. Low end flooding of
ditches and fields is probably occurring along some small creeks
from the ongoing snowmelt, especially north of I-80.

The latest model runs still suggest a return to more active weather
the second half of next week.  However, it currently appears the
heavier rains may fall across MO into central IL. That said, river
interests across the southeast half of our CWA should continue to
monitor the forecast for late next week.

&&

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

$$

SYNOPSIS...14
SHORT TERM...14
LONG TERM...Uttech
AVIATION...Sheets
HYDROLOGY...14



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