Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 160507

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1207 AM CDT Sun Oct 16 2016


Issued at 235 PM CDT Sat Oct 15 2016

Analysis at 2 PM shows partial clearing has made it as far north
as I-80 with more clouds now moving in from the west. Temperatures
are in the lower to middle 70s with the partial clearing and 60s
further north. Nowcast tools shows cloudy skies should once again
envelop all the region around or just after sunset. A weak vort
max in nebraska appears strong enough to fire some evening showers
and storms this evening. Southwest winds next few days support
above to well above temperatures into Tuesday.


.SHORT TERM...(This Evening through Sunday)
ISSUED AT 235 PM CDT Sat Oct 15 2016

Short term forecast confidence assessment...fair or average. The main
issue is timing and coverage of convection this evening with showers
and storms. How strong storm coverage is also an issue with trend toward
at most some isolated strong storms with maybe small hail and some gusty
winds over 30 MPH within a few hours of convective initiation.

Tonight...local tools suggest convection should fire early to mid evening
along or just west of the I-380 corridor. Limited instability...mostly
aloft of MUCAPE AOB 1000/J/KG supports convection should evolve in mostly
rainshowers and embedded thunder by around midnight into early morning
hours. Precipital water values of around 1.5 inches suggest some areas
of .5 to locally .75 inches plus are possible. Have likely pops over
northern 2/3 of the area. Most locations should receive lighter amounts
of around a quarter inch and some lesser amounts, probably most south
of highway 34. Lows should remain quite mild in the lower to middle
60s with south winds of 5 to 10 MPH becoming light late. Have patchy
to areas of fog toward morning as rain and low level moisture show this
could be significant enough for a headline for later shifts.

Sunday...areas of fog expected and may be locally dense, especially
along and north of I-80 with low clouds. Highs once again should be
a challenge with lower 70s north of highway 30 and clouds to lower 80s
with partial clearing by mid day along and south of highway 34.

.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 235 PM CDT Sat Oct 15 2016

Sunday Night...Broad low pressure across the Dakotas and sfc
pressure gradient to the SE will maintain steady S-SE winds over E
Iowa/NW Illinois. Temps and dewpoints in the 60s will set up a mild
and humid night - like a summer night but in the middle of October.
Average lows this time of year are in the lower 40s.

Monday...Very warm. Upper 70s to upper 80s from north to south
through the forecast area. Near record highs are possible.
850mb low progged to track from Nebraska into Minnesota. On the SE
flank of the low, the height gradient becomes very tight which
causes SW 850mb winds to increase from 30 kts early in the day to
60kts by the evening. An elevated-mixed layer originating over the
west-central Plains of SE Colorado, SW Kansas, and the Panhandles of
Oklahoma and Texas will rapidly advect northeastward via the
impressive lower tropospheric kinematics, warming 850mb temps to 19-
20 C (2-2.5 standard deviations above normal).

Elevated Fire Weather Risk and Winds: Synoptic pattern of a strong
low-level jet juxtaposed to a low and dry/clear condtions usually
associated with efficient boundary layer mixing and gusty winds.
Current forecast is for SW gusts of 30-35 mph. If wildfires were to
ignite in crop fields, they would spread quickly given the strong
winds. Also, there is potential for higher gusts near or above 40
mph and lower relative humidity (if dewpoints mix down into the 50s)-
leading to greater fire weather concerns. Highest risk at this time
is south of highway 30.

Tuesday and Wednesday...High pressure sliding through before another
low develops in the Central U.S. later in the week. Well above
average highs into the 70s on Tuesday will drop off about 5-10 F by
Wednesday. High confidence in dry weather on Tuesday. Then models
diverge for Wednesday into Friday. The ECMWF is the outlier breaking
out widespread rain Tuesday night into Wednesday. The GFS/Canadian
hold off until Wednesday night.

Wednesday Night through Friday...Western U.S. trough will dig and
progress eastward into the Plains and Midwest. Could have a
prolonged period of steady rain as low forms along SW to NE
baroclinic zone. The exact location and timing of both of these
features will likely change over next few days. As mentioned, the
ECMWF is an outlier to the NW with greater impacts over the DVN CWA.
The GFS/Canadian are further SE with the frontogenetic rain band,
taking the heaviest rain and most robust forcing through Missouri
and central Illinois. Temps will cool through the period, only
reaching the 50s on Friday with 30s/40s Friday night.

Saturday...Large upper-low pulls away into the Ohio Valley, so we
should be mostly dry. Low-end POPs may be removed in future forecast
updates. Otherwise, model consensus has seasonal temps near 60 F.


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
ISSUED AT 1156 PM CDT Sat Oct 15 2016

A cool front will drop southeastward across eastern Iowa this
morning before stalling. Winds will briefly turn southwesterly
early this morning with the front before returning to the south
as the front moves northward.

Expect showers at all taf sites through 09 utc with aviation fog
to develop at all taf sites with visibilties possibly as low as
LIFR at CID and DBQ. Visibilities and ceilings will begin to
improve after 16 utc with possible vfr ceilings by 20
utc...similar to today. Have left it out of the tafs for now but
some concern that low clouds and fog will develop again late
Sunday into Monday.




SHORT TERM...Nichols
LONG TERM...Uttech
AVIATION...Cousins is the U.S. government's official web portal to all federal, state and local government web resources and services.