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fxus63 kdvn 181130 
afddvn

Area forecast discussion
National Weather Service Quad Cities Iowa Illinois
630 am CDT Fri Oct 18 2019

..12z aviation update...

Synopsis...
issued at 136 am CDT Fri Oct 18 2019

The area is situated in developing southerly return flow, on the
backside of a departing surface ridge into the Ohio Valley.
Meanwhile, low pressure is organizing over the northern plains.
The developing and strengthening southerly wind in between these
two systems, will spell warmer temperatures over the next 24 hrs.

&&

Short term...(today and tonight)
issued at 136 am CDT Fri Oct 18 2019

Key messages...
1) breezy to windy today, with above normal temperatures.
2) elevated fire weather conditions for cured ag fields.
3) showers arrive late tonight well west of the Mississippi River.

Tightening pressure gradient and mixing will lead to breezy to
windy conditions today. Mixing of winds to near 900 mb support
S/southeast surface gusts of 25 to 35 mph this afternoon, with the
highest gusts across the west. If deeper mixing occurs then
slightly higher gusts are possible. Mixing to near 900 mb
yields highs generally ranging from the mid 60s to around 70.
Highs could also be a few degrees warmer if high clouds thin
earlier aiding more hours of full solar insolation and subsequent
deeper mixing. Consequently, we're getting into that time of year
with shorter days where thicker/more opaque cirrus can have
greater negative impacts on highs. So it's best to mention this
possibility as well though seemingly a lower one, as only a couple
pieces of guidance are slow in evacuating the cirrus. The
combination of the gusty winds, above normal warmth, and also
drying (rh lowering to between 35 to less than 50 percent this
afternoon), will result in elevated fire weather concerns for
cured agricultural fields.

Tonight clouds will increase overnight, and followed by showers
toward daybreak well west of the Mississippi River along an
approaching cold front. Winds may remain gusty at times,
especially during the evening. The combination of the gusty winds
then increasing clouds should result in milder lows in the mid to
upper 40s, with the potential for a few sites to be around 50
across the west/southwest County Warning Area.

Long term...(saturday through thursday)
issued at 136 am CDT Fri Oct 18 2019

Active long term period again with the beginning of the period
seeing a chance for rain. Sunday night into Monday a strong
wave is forecast to move through the area. After this a wave
in the northwest flow will bring schc for pops midweek. Overall next
week will be more seasonable across the area.

At the beginning of the period there are two waves that are
phased west of the area. The northern wave turns negatively
tilted across Canada. The southern wave is slower to turn
negative to our south. As a result forcing should wane as the day
GOES on. The best chance for rain looks to be through late
morning. This looks to be tied to northernmost wave. As it swings
to the NE so does the chances for rain. The cams support this
notion as well. Overall rainfall looks light and as previously
mentioned, should not affect rivers much at all.

The system at the beginning of the week looks like a much stronger
wave. A closed 500 mb low is expected to move across the area. As it
moves across the area, the upper level wave swings negative.
Current guidance suggests that the best forcing and rain/storm
chances will be east of the area. If this wave slows down at all,
then we will have better chances of rain and storms. Nonetheless,
there is a still a schc for thunder during the day Monday. Winds
will become stronger in the afternoon as colder air makes its way
in behind this wave.

&&

Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 625 am CDT Fri Oct 18 2019

VFR conditions expected to persist through much if not all of the
taf period. Winds will be gusty from mid morning into this
evening from S/se, and could be sustained at or above 20 kts
at times at Cid and dbq. A strengthening low level jet will Foster an
increase in winds to around 40 kts at 2kft agl tonight, and
low level wind shear may need to be added in later tafs if it appears the bl
will decouple. Shower chances will begin to arrive after 09z
tonight west of the Mississippi River, as a cold front approaches.
Conditions may lower to MVFR with pockets of IFR at the end of
the taf period at Cid and possibly dbq, and elsewhere evolving on
Saturday.

&&

Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&

$$

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