Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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977
FXUS63 KDVN 282248
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
548 PM CDT Tue Mar 28 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 330 PM CDT Tue Mar 28 2017

18Z surface data had high pressure from the northern Great Lakes
into the upper Midwest while a frontal boundary ran from north Texas
into the Tennessee Valley. Dew points were in the 30s and 40s from
the Great Lakes into the central and northern Plains with 50s and
higher from the Ohio Valley to the Gulf Coast.

&&

.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 330 PM CDT Tue Mar 28 2017

The question for late this afternoon and tonight is how far south
will the clearing get.

Based on satellite trends, the clearing looks to start crossing the
WI/IL border around 4 PM and slowly move south through mid-evening.
When higher level clouds are added into the picture, the clearing
light should stop short of highway 30 during the evening with clouds
moving back in after midnight. Where the clouds do clear out tonight
lows should be in the mid 30s.

Mainly dry conditions will be seen tonight across the area. The
exception looks to be Scotland county Missouri where sprinkles or
very light rain may move into the area just prior to sunrise.

On Wednesday, rain will develop and overspread the area from
southwest to northeast during the day. Cloud cover and the rain will
dictate how warm it gets but much of the area will remain below 50
degrees for a high temperature.

.LONG TERM...(Wednesday Night through next Tuesday)
ISSUED AT 330 PM CDT Tue Mar 28 2017

Wednesday night and Thursday...Warm moist conveyor fed up by
southerly 30-40+ KT LLJ, still appears on track to fuel a moderate
to locally heavy elevated rain event Wed night into Thu morning.
Projected PWAT feed of 0.80 to near 1.2 inches, and rounds of lift
could wring out widespread 0.75 to 1.25 inches of rain by Thu
afternoon...with localized swaths of 1.5 to 2 inches possible. We
should be able to take those kind of amounts if they fall in 12-18
hours with minimal flood threat, but do expect within bank rises on
area rivers and streams. Also ponding of water on roads and
drainage ditches.

Convergent nose of the organizing H85 MB jet and fcst sounding-
projected mid layer MUCAPES of 150 to near 400 J/KG support embedded
thunderstorms tomorrow night rooted at the H85-H825 MB layer. There
appears enough storm layer shear to support at least some small
hail with the more organized cores aloft especially with initial
storms Wed evening. Then Blocked, near vertically stacked and
possibly multi-center cyclone complex acrs MO into central IL to try
and "in-whirl" a narrow dry slot(or slots) from the southern plains,
which could make for a few more bands of elevated storms at times on
their leading edge during the day on Thu especially acrs the
southeastern half of the CWA. Sfc temps to suffer under rather sharp
and llvl inversion Thu with most highs only in the 40s to low 50s.
Closed blocked low to slowly wander east acrs central IL into IN Thu
night into Fri morning, with wrap around rain waning as the night
progresses. Will still bank on a brisk northeasterly breeze on
northwestern flank/pressure gradient of the low Thu night to mix out
any dense fog potential. Lingering precip stays all liquid into Fri
morning.

Friday...This day could be a rather raw one if wrap-around clouds
maintain with no afternoon break in subsidence wake of eastward
migrating/filling low pressure system. brisk north to northeast sfc
winds and highs held in the 40s. At least the latest medium range
models have trended dry for the day, and if we get some afternoon
breaks more sites to near 50 degrees. Lighter winds and clearing
under both sfc and upper ridging regimes will make for a seasonably
chilly night Fri night with lows in the low to mid 30s...close to
normal for April 1st.

Saturday and Sunday...while the next cyclone lurks acrs the southern
plains, feel ridging will make for a dry day for most of Sat with
maybe just some increasing cloud cover from the west as the day
progresses. Break in cloud cover with dry conditions to translate
into normal highs for Sat. Lead wave may lead to some light
overrunning rain or sprinkles Sat night into Sunday, but easterly
dry fetch flow to battle this process.

Monday and next Tuesday...Latest run medium range ensembles suggest
the main piece of upper wave energy to roll out along and south,
then southeast of the CWA Mon into Tue, like several of it`s
precursor cyclone systems. Thus another wet period on the
northwestern flank of this system to start the work week off with,
but confidence still marginal with run-to-run model gyrations.
Model loaded/guidance highs look too mild for Mon into Tue if we get
affected by this system.   ..12..

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
ISSUED AT 544 PM CDT Tue Mar 28 2017

Generally MVFR conditions through the period except periods of fair
skies and VFR conditions at DBQ and possibly CID terminals this evening.
Cloud bases will be lower MVFR late morning and afternoon as rain moves
in along with 2-4 miles in rain as a storm system moves in from the
south.

&&

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

&&

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...12
AVIATION...Nichols



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