Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 230450
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1150 PM CDT FRI JUL 22 2016

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 322 PM CDT Fri Jul 22 2016

18Z surface data has the main synoptic front from central lower
Michigan, through southern Minnesota, and then to around KFSD. Dew
points were in the 70s along and south of the front with 60s north
of the front.

&&

.SHORT TERM...(This Evening through Saturday)
ISSUED AT 322 PM CDT Fri Jul 22 2016

The current heat headlines will remain in effect across the entire
area.

New convection has developed across north central Iowa west
southwest of KMCW. Some additional showers with isolated
thunderstorms have moved into the far western areas associated with
a remnant boundary from the overnight convection.

What is being suggested by the models is that isolated to low end
scattered showers and thunderstorms will continue across eastern
Iowa into the late afternoon. Internally, some model trends indicate
the convection across north central Iowa will grow upscale into
another thunderstorm complex by early evening and move in the area.

If this scenario occurs, another round of thunderstorms with heavy
rain will be seen across the area. Some parts of northeast Iowa and
northwest Illinois are quite moist from several rounds of heavy
rainfall the past several days. The current round of convection will
need to be watched to see how it evolves late this
afternoon/evening. If this new convection affects the same areas
that are already quite wet, a flash flood watch `may` be needed for
a small part of the area.

Late tonight, another thunderstorm complex may develop and move
through the area. The model solutions vary greatly on whether or not
this will occur. The current forecast goes on the assumption there
will be a second thunderstorm complex.

Saturday...assuming a second thunderstorm complex develops and
affects the area late tonight then showers and some thunderstorms
should be seen during the morning. Convection would decrease during
the late morning with clearing occurring around mid-day. If the
overnight convection is strong enough, temperatures may struggle to
reach the forecast highs and related heat index values on Saturday.

.LONG TERM...(Saturday Night through Friday)
ISSUED AT 322 PM CDT Fri Jul 22 2016

Saturday night could be quite stormy around here. At the moment, it
seems likely that a strong outflow boundary could be over the cwa
during the afternoon, becoming the focus for intense convection late
in the day and evening. Meanwhile, a stronger short wave than has
been seen in the past few days will arrive from the west Saturday
night. This combination will lead to a progressive MCS over Iowa,
likely merging with the ongoing storms in our cwa. I see a potential
for training in this process and heavy rainfall Saturday night, and
that may need a flash flood watch once details gain confidence. In
any case, I am confident that an event will occur, but placement may
change as storm evolution occurs tonight into Saturday.

Nearly all models are dry Sunday, despite the cold front moving
through during the day. I retained slight pops for that period in
case we can fire a storm, but it does look capped, with a fropa
early enough in the afternoon to not get a full benefit of
prefrontal heating. Sunday will be breezy, with decreasing humidity
levels in the afternoon. That said, should somehow storms not hit
Saturday night, a continuation of heat headlines may be needed into
Sunday.

Sunday night through Tuesday continue to look very pleasant,
seasonally warm, and dry. High pressure will be transient though,
and by Tuesday night, elevated showers and storms are likely to
develop in Iowa. The main focus for showers and thunderstorms looks
to be near our area Wednesday and Thursday, with the front near the
Iowa and Missouri border. That position should keep most locations
with only a heavy rain threat, rather than severe weather.  Time
will tell if the models frontal position is accurate. Temperatures
appear the be mainly in the lower to mid 80s Wednesday through
Friday, as clouds hold down highs, while lows only fall to the mid
to upper 60s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
ISSUED AT 1149 PM CDT Fri Jul 22 2016

Generally VFR conditions and fair skies overnight. Patchy very
light fog may be possible toward morning. A thunderstorm complex
in mature and decaying stages may arrive by late morning. This is
handled with cloud ceilings aob 7k agl and and again vicinity
wording. Winds will tend to be southerly and less than 5 kts.

&&

.DVN Watches/Warnings/Advisories...
IA...Excessive Heat Warning until 7 PM CDT Saturday for Benton-
     Buchanan-Cedar-Clinton-Delaware-Des Moines-Dubuque-Henry IA-
     Iowa-Jackson-Jefferson-Johnson-Jones-Keokuk-Lee-Linn-Louisa-
     Muscatine-Scott-Van Buren-Washington.

IL...Excessive Heat Warning until 7 PM CDT Saturday for Bureau-
     Carroll-Hancock-Henderson-Henry IL-Jo Daviess-McDonough-
     Mercer-Putnam-Rock Island-Stephenson-Warren-Whiteside.

MO...Excessive Heat Warning until 7 PM CDT Saturday for Clark-
     Scotland.

&&

$$

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



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