Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 242032
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
332 PM CDT Fri Mar 24 2017


.SYNOPSIS...
Issued at 327 PM CDT Fri Mar 24 2017

18Z surface data has a frontal boundary from Lake Huron into
southwest Wisconsin and then into extreme southeast Nebraska. Dew
points ahead of the front were in the mid 40s and 50s with mainly
30s behind the front.

&&

.SHORT TERM...(This Evening through Saturday)
ISSUED AT 327 PM CDT Fri Mar 24 2017

The front is making steady progress across the area this afternoon.
As of 3 PM it was essentially straddling the Mississippi river and
should be east of all of the Mississippi by sunset.

Any thunder associated with the precipitation moving into the area
was dissipating and this trend is expected to continue until sunset.
Through sunset areal coverage of the precipitation will continue to
increase across the area with areas west of the Mississippi having
the best chance at seeing some light rain.

Tonight, rain will increase in areal coverage as more moisture
streams into the area and the overall forcing increases. Embedded
thunderstorms will develop tonight across the southern half of the
area and slowly sink to the south through sunrise.

On Saturday, breezy and rainy conditions will be seen across the
northwest half of the area with temperatures 25 to 30 degrees colder
than the day before.

Across the southeast half of the area, the rain will continue with
embedded thunderstorms and temperatures 15 to 20 degrees cooler than
the day before.

A back door cold front will slide south of Lake Michigan and
intersect the other cold front across the southeast third of the
area Saturday afternoon. The passage of the upper level system may
help to induce some very low end severe thunderstorms south of a
Peru, IL to Keokuk, IA line during the late afternoon hours. The
primary threat looks to be hail.


.LONG TERM...(Saturday Night through Friday)
ISSUED AT 327 PM CDT Fri Mar 24 2017

Active weather with slightly above normal temperatures are the main
themes of the long term forecast period.

Into Saturday evening, will need to continue to monitor for low risk
of severe storms. This scenario is dependent on a front advancing
into the far southeast counties, and sufficient insolation with
partial late afternoon clearing. CAMS suggest isolated cells pin-
wheeling north/northwest, mainly south of Interstate 80, through
early evening. If there is enough instability and a nearby boundary,
steep low level lapse rates combined with an H5 cold pool would lead
to potential of enhanced stretching of vertical vorticity. So, the
main issue would be a low risk of isolated tornadoes with mini-
supercells, and possibly some marginally severe hail.

Looking ahead, showers will continue Sunday as the closed low
finally lifts out. Rainfall Friday night through Sunday will cause
renewed in bank rises on some area rivers. The Wapsi near DeWitt is
forecast to crest around 10 feet late Sunday night. Impacts of the
moderate to locally heavy rain will become more clear in the next 1
to 2 days.

For Monday, another low will skirt the region, with additional rain
favored along and south of Interstate 80. Late Wednesday through
Thursday, there is potential for another closed low to impact the
forecast area with widespread rains.

Temperatures will remain fairly stable, and slightly above normal
through the long term, with no significant changes in air mass.
Expect highs mainly in the 50s with lows in the upper 30s and 40s.


&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
ISSUED AT 327 PM CDT Fri Mar 24 2017

VFR conditions will slowly deteriorate to MVFR west of the
Mississippi through 00z/25. After 00z/25 widespread MVFR
conditions will develop with KBRL having the best chance at seeing
a TSRA. KMLI may or may not see a TSRA. After 06z/25 widespread
IFR conditions are expected to develop across most of eastern Iowa
and northern Illinois.

&&

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

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...RP Kinney
AVIATION...08



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