Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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049
FXUS63 KDVN 270427
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1127 PM CDT Mon Jun 26 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 325 PM CDT Mon Jun 26 2017

Sfc trof noted extending southwestward out of the GRT LKS and into
the local CWA north of I80. This a sfc reflection of short wave
embedded in cyclonic northwesterlies aloft. Enough convergence an
lift in the VCNTY of these features to drive the ongoing isolated to
sctrd showers/storms that many of the earlier CAM runs picked up on.
An isolated cell may still strengthen/pulse up through 5-6 PM and
produce pea to half inch size hail before collapsing back in on
itself. Then another clear cool night in store for tonight, a
beautiful late June day tomorrow, before strengthening southerly
return flow/ moisture feed combines with a flattening mean steering
winds/ westerlies to make for a much more unsettled mid to late week
period.

&&

.SHORT TERM...(This Evening through Tuesday)
ISSUED AT 325 PM CDT Mon Jun 26 2017

Tonight...The ongoing convection will look to continue to shift
south and wane through 6-8 PM CDT, and will only have POPs in the
far south for the first few hours(00-02z)of the tonight period. Then
cellular CU to decay for a clear cool night with decreasing sfc
winds. Ongoing low sfc DPT regime should allow for lows in the lower
50s to upper 40s in most of the local fcst area. A few climate sites
such as Burlington, may dip down to just a few degrees above the
record lows for the 27th. Will leave the patchy fog wording added by
the Mid shift in portions of the area for now, but ongoing dry sfc
layer may preclude much of any fog worth mention except in river
valleys toward dawn Tue morning.

Tuesday...A fair weather day under a passing ridge of high pressure.
light winds in the morning to increase and become south to southeast
in the afternoon behind the passing anticyclone, especially west of
the MS RVR. Sunshine and mixing in ongoing lower humidity regime,
along with moderating low to mid level thermal profiles to make for
widespread highs in the mid to upper 70s. Just a few fair wx CU
expected in the east and northeast.   ..12..

.LONG TERM...(Tuesday Night through next Monday)
ISSUED AT 325 PM CDT Mon Jun 26 2017

Overview: Stormy pattern in the extended with the potential for
severe weather and torrential rainfall.  Temperatures near to
slightly below normal with maximum temperatures in the upper 70s to
mid 80s, and lows in the 60s to around 70.  Will need to monitor
river levels as several heavy rain events in the extended may cause
significant rises.

Wednesday and Wednesday night: Low pressure will be tracking across
MN and WI in the zonal flow. Models indicate strengthening deep
layer shear with a 50 kt southwesterly low level jet and a 50 kt
westerly mid level speed max. Storm relative helicity is progged at
400 m2/s2 with MUCAPES 2500-3000 J/KG. All modes of severe weather
(damaging winds, large hail and a few tornadoes) are possible. SPC
day3 has a slight risk over the entire cwa, and this may be upgraded
in future outlooks. What will need to be monitored is the amount of
cloud cover (or lack of) which may impact instability and the
severity of the storms. PWAT`s increase to 2 inches so any storms
will also dump torrential rain. The corn crop is rapidly growing so
this will add additional moisture (water vapor) through the process
known as evapotranspiration.

Thursday: Weak cold front gradually settles into extreme northern MO
and central IL with any thunderstorm activity in our southern cwa
closer to the front. It is possible the front may hang up a bit
farther north. Deep layer shear is rather weak but PWAT`s remain
high so torrential rainfall in the stronger storms is the primary
threat. However, can`t rule out severe storms depending on
instability.

Thursday night into Friday morning: Models develop a rather large
MCS across the cwa. Deep layer shear looks weak so widespread heavy
rainfall likely. Still pretty early in the game for specific amounts
so stay tuned. This due to another low pressure system moving across
the area in the zonal flow.

This weekend: An upper level low dives into the upper Midwest with a
trailing cold front moving into the cwa and then stalling. This
front will have a chance of thunderstorms.

Early next week: Yet another rather large MCS is indicated across
the cwa Sunday night and Monday with heavy rainfall, as another low
pressure system arrives in the zonal flow.

Haase

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
ISSUED AT 1127 PM CDT Mon Jun 26 2017

VFR conditions continue through TAF period with a light and
variable wind becoming southerly Tuesday morning.

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...Haase
AVIATION...RP Kinney



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