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fxus63 kdvn 202205 
afddvn

Area forecast discussion
National Weather Service Quad Cities Iowa Illinois
505 PM CDT Sat Jul 20 2019

Update...
issued at 502 PM CDT Sat Jul 20 2019

I will continue to chop away at the heat warning as the outflow
boundary south of I-80 gradually shifts southward. Nevertheless,
the warning expires at 7 PM.

Meanwhile, severe cluster of storms near Des Moines and other
storms developing in central Iowa should move east and southeast
into the dvn cwa this evening along the cape gradient. The main
hazards will be 70 mph winds, continuous lightning and torrential
rainfall.

&&

Synopsis...
issued at 315 PM CDT Sat Jul 20 2019

Severe thunderstorms with damaging winds have been numerous across
northern Iowa/southern Minnesota and WI today. For much of the day the
strong cap has held but now beginning to weaken in the northern
cwa as a cold front approaches from the north. Temperatures were
in the 90s with dewpoints in the 70s ahead of the front, with
readings in the 60s in southern Minnesota.

Sbcapes of 5000 j/kg south of the front with bulk shear 45 knots
sinking into the northern cwa. Pwat's were near 2 inches.

&&

Short term...(this evening through sunday)
issued at 315 PM CDT Sat Jul 20 2019

Tonight: cold front will continue to sag southward overnight with
numerous thunderstorms developing around the front. Severe storms
expected through this evening and possibly into the overnight
hours. Damaging winds to 70 mph will be the main risk, but will
also include continuous lightning and torrential rainfall. Pwat's
increase to a whopping 2.25 inches so flash flooding is possible
if storms repeat over the same area. A Flash Flood Watch may be
needed if this scenario unfolds. Should be able to allow the heat
warning to expire this evening. Lows will be in the upper 60s
north to the mid 70s south.

Sunday: numerous thunderstorms will occur especially in our
southern half as the cold front continues to push slowly
southward. In many areas this will be a much cooler day with highs
in the upper 70s north to the mid to upper 80s south.

Long term...(sunday night through saturday)
issued at 315 PM CDT Sat Jul 20 2019

Much cooler and drier next week

Sunday night, scattered showers will be possible over the southern
half of the forecast area mainly south of Interstate 80. Any
showers will end after midnight, with overnight low temperatures in
the mid 60s.

Monday through Thursday, a much cooler and drier airmass will build
over the upper Midwest as a long wave upper level ridge develops
over the inter-mountain west, with a closed high forming over The
Four Corners region of the County. The resulting upper level flow
over the upper Midwest will be from the northwest as a deep upper
trough also digs over the eastern U.S. At the surface, high pressure
will usher in much cooler and drier air. High temperatures will
range from the upper 70s to low 80s each day. Surface dewpoints will
be in the upper 50s to mid 60s producing cool low temperatures in
the upper 50s to around 60.

Friday into next Saturday, the upper level ridge will move slightly
to the east, raising temperatures to near normal with daytime highs
in the upper 80s and overnight lows in the 60s. A ridge riding
shortwave will push through the upper ridge and move across the
region. Chances of storms will return with this system. ..Kuhl..

&&

Aviation...(for the 18z tafs through 18z Sunday afternoon)
issued at 113 PM CDT Sat Jul 20 2019

VFR conds through this evening except MVFR/LCL IFR in/near thunderstorms and rain.
Thunderstorms will become more numerous this evening and overnight
as a cold front moves into the area. Then winds becoming north to
northeast behind the front with a period of MVFR cigs.



&&

Dvn watches/warnings/advisories...
Iowa...excessive heat warning until 7 PM CDT this evening for Des
Moines-Henry Iowa-Jefferson-Keokuk-Lee-Louisa-Muscatine-Scott-
Van Buren-Washington.

Illinois...excessive heat warning until 7 PM CDT this evening for Bureau-
Hancock-Henderson-Henry Illinois-McDonough-Mercer-Putnam-Rock
Island-Warren-Whiteside.

MO...excessive heat warning until 7 PM CDT this evening for Clark-
Scotland.

&&

$$

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