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fxus63 kdvn 211154 
afddvn

Area forecast discussion
National Weather Service Quad Cities Iowa Illinois
654 am CDT sun Jul 21 2019

..aviation update...

Synopsis...
issued at 236 am CDT sun Jul 21 2019

At 3 am, a cold front stretch from southwestern Ontario to Ord to
kfsw to the Nebraska and Kansas border. Temperatures ranged from
68 degrees at Independence to 75 at Fort Madison. Dewpoints ranged
from 67 at Independence to 72 at Keokuk. Precipitation from last
nights mesoscale convective system lingered over Scotland and Clark counties in Missouri.
Skies were overcast across the area.

&&

Short term...(today and tonight)
issued at 236 am CDT sun Jul 21 2019

The main forecast concerns are chance of precipitation.
The ecwmf is slower with the frontal boundary in the short term
and lags the NAM, GFS, and Canadian in moving it southward today.

The GFS, NAM, and Canadian have the cold front exiting into
northern Missouri at 12 UTC on Sunday while the European model (ecmwf) lingers it
near the Iowa and Missouri border. These differences continue
through the day with the European model (ecmwf) lingering the front across northern
Missouri. This is important as a shortwave will move across the
area late this afternoon and into this evening. If the GFS, NAM,
and Canadian are correct an mesoscale convective system will move along the front across
Missouri with the stratiform rain region spreading northward into
our area potential as far north as a Fairfield to Galesburg line
while the European model (ecmwf) would bring the precipitation as far north as the
Interstate 80 corridor. The forecast for precipitation through the
day sides more with the GFS, Canadian, and NAM forecast.

Today will be noticeably cooler and comfortable. Temperatures and
dew points will be 10 to 15 degrees cooler across the area today
with the front to our south and cloud cover across the area.

Long term...(monday through saturday)
issued at 236 am CDT sun Jul 21 2019

Fairly quiet period on tap for the work week, turning more active
over the weekend.

On Monday morning, a potent shortwave trough will be making its way
south across the upper Midwest which will serve to be the final
punch to get the lingering moisture and out of the local area and to
push the frontal boundary further southward. Timing of the shortwave
trough may keep some lingering showers across the southeast part of
the forecast area Monday morning. Confidence in precipitation
chances Monday morning are low as the showers could easily move out
of the area prior to 12z, but also didn't have enough confidence in
the speed of the system to remove chances at this time.

This system will usher in a cooler and drier airmass with 850mb
temperatures dropping to around 10c-11c for a period of time from
late Monday through Tuesday. Highs Monday and Tuesday are looking to
be in the upper 70s/low 80s, but the bigger story will be the lows
Monday night. After very mild low temperatures over the past week,
with the cooler airmass in place, lows are looking to drop into the
50s for much of the forecast area Monday night.

Surface high pressure will take residence over the plains for Monday
through Tuesday before migrating eastward. At this time, the local
area will be firmly placed in northwest flow. With cooling aloft,
could get steep low level lapse rates during the afternoon both days
as surface temperatures warm into the upper 70s and low 80s. This
will promote mixing to around 925-950mb which will cause some breezy
conditions during the afternoon hours. A bit of instability is
apparent in forecast soundings so while it is possible to get the
development of afternoon diurnal convection, it may just end up
being a deck of cumulus coverage. This trend does continue
through Wednesday and into Thursday, especially in the 21.00z GFS,
as the model tries to develop convection on the northeast
quadrant of the surface high. But, moisture is lacking as the
surface high comes overhead on Wednesday and shifts a bit eastward
on Thursday. Have not included precipitation chances in the
forecast any of these days (m-th), but may want to keep this idea
in mind in case the signal begins to look better.

Do start to see dewpoints begin to increase and temperatures warming
going into Thursday and Friday and through the weekend as the
surface high moves off to the east changing the flow back to
southerly flow with an indication for the Gulf to open back up. The
ongoing forecast is pretty conservative in terms of raising
dewpoints and so they were kept in the 60s for the outer periods of
the forecast. Could easily see needing to up dewpoints into the 70s
by Friday afternoon.

Models are showing shortwave trough moving out of southern Canada
and over the Great Lakes during the late part of the week. This
system should bring enough support for precipitation chances to be
needed for Friday into Saturday. At this point, the upper level
ridge is over the southwestern conus, putting the local area in the
downward side of the ridge which could put the area in the path for
ridge riding mcs's. So looking at a potential for more active
weather next weekend.

&&

Aviation...(for the 12z tafs through 12z Monday morning)
issued at 641 am CDT sun Jul 21 2019

VFR conditions at kdbq, kbrl, and kmli with MVFR ceilings at kcid.
MVFR ceilings are forecast to shift southward this morning to
kmli by mid morning with ceilings lifting during the afternoon.
Kdbq and kbrl will remain VFR through the period.

Scattered showers and storms are possible today but there is
low confidence that they will effect any of the taf sites so left
them out of the forecast for now.

&&

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

$$

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