Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 171236

Area Forecast Discussion
National Weather Service Quad Cities IA IL
636 AM CST Tue Jan 17 2017

Issued at 635 AM CST Tue Jan 17 2017

Visibilities have improved enough that we can cancel the NPW in
all counties. A cloudy day looks on track.

UPDATE Issued at 536 AM CST Tue Jan 17 2017

Dense fog is lifting, but still is mainly in place over the north
half of the area. Surrounding offices are cancelling and we will
do so as well, but will wait until visibilities lift above 1/2
mile to keep an assurance that clearing counties is going to be
an ongoing trend.


Issued at 314 AM CST Tue Jan 17 2017

Rain has moved east of the CWA, leaving only a few patches of very
light drizzle in the wake of the mid level moisture which is moving
off to the east. Plentiful low clouds are in place throughout
southern MN and all of Iowa.  Under the low clouds, we are still
seeing dense fog areas, in the convergent flow found generally along
and north of Interstate 80.


.SHORT TERM...(Today and Tonight)
ISSUED AT 314 AM CST Tue Jan 17 2017

Dense fog will persist in the northern half of the cwa, roughly
through mid morning until the convergent flow shifts east of the
area. However, the fog is not continuous, and if the widespread
nature does decrease, and early cancellation may be need to the

While the fog will end today, the clouds likely will not. Persistent
stratus is a near guarantee today with so much moisture in place and
dry advection holding off until later tonight. Tonight may also see
stratus linger for much of the night, especially east. This leads us
to a day where we can only expect a few degrees of a diurnal rise,
with highs in the mid 30s northwest to upper 30s east.  With some
partial clearing possible tonight, lows should fall to the mid to
upper 20s.

.LONG TERM...(Wednesday through Monday)
ISSUED AT 314 AM CST Tue Jan 17 2017

Spring-like weather pattern still on track for the long term period
with guidance advertising well above average temperatures.  Overall
H5 pattern starts out similar to a rex block, however rather more
progressive than a blocking pattern.

Wednesday through Friday has a rather high amplitude ridge across
the central US.  This ushers in much warmer air leading to warm up
across the area.  The slow moving H5 low south of the area finally
starts to eject north a strong low off the Pacific Coast moves
onshore.  This low is ejected towards our area and could lead to
some precip.  Models are usually fast with the movement of these
systems and there will likely be changes to forecast that will
affect sensible weather into the weekend.  Temperatures into the
upper 40s and low 50s still look possible for the weekend.

The pattern this weekend looks to be active with a series of waves
moving through the flow.  This will lead to chances of precip.  As a
result, there are chances of rain through the weekend.  The best
chance for precip looks to be Sunday.  The main story with this
system is that the threat for frozen precip is very low, in fact it
looks to be all rain for the weekend system.

Late in the period, another system is forecast for the area. This
system could lead to our next real chance of winter weather.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
ISSUED AT 522 AM CST Tue Jan 17 2017

Very low cigs, and fog, dense north of interstate 80, will slowly
improve today, and by 15Z, all sites should be seeing visibility
around 4-6 miles with cigs remaining around 500 ft. Some slow
improvement is possible through this evening, then overnight, a
transition to MVFR should occur before eventual clearing early
Wednesday morning.




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