Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 190428

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1128 PM CDT Tue Oct 18 2016


Issued at 313 PM CDT Tue Oct 18 2016

Latest SFC analysis was indicating high pressure center acrs the
west central plains, while the front that passed through the area
this morning was progressing from northeastern lower MI, down into
eastern OK ATTM. Aloft, broad southwesterlies were aligning from the
northeastern CONUS/ME, down to troffiness acrs the GRT BSN region.
Drier sfc DPTs, full insolation, and mixing northwest winds have
helped warm temps up into the low to mid 70s acrs most of the DVN
fcst area.


.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 313 PM CDT Tue Oct 18 2016

Tonight...Upstream high pressure center will settle east acrs much
of IA through Wed morning. Winds to decouple and become light from
this evening into the overnight, while the first half of the night
remains mainly clear. Then several models increase high level/CI and
even some mid level clouds acrs the area from the southwest from
upstream trof base in mean steering flow. Confidence in this
happening is rather low, looking currently upstream in source region
on latest VIS Satellite loop. But will trend at least to partly
cloud late after midnight. Will bank on the blanketing effect of
this incoming cirrus and maintain ongoing lows mainly in the upper
40s, with a few river valley/cool air drainage locations dipping
toward the mid 40s. If the clouds don`t materialize, fcst lows
likely to be too mild with light winds and DPTs in the mid 40s. Some
river valley fog also possible.

Wednesday...The main sfc front will look to align parallel under
the steering flow from the southern plains up the OH RVR Valley.
With the main upper trof axis adjusting east acrs the southern and
central plains, and lee upper jet max streaking from acrs IA up into
southeastern Canada, the main convective action zone will take place
tomorrow afternoon and evening along the main llvl boundary. But
secondary lift zone of isentropic nature (looking at the 305 to
310K sfc`s) appears to saturate the column enough acrs the
southeastern third of so of the DVN CWA by mid to late afternoon
to allow at least some sprinkles or light showers to precipitate
out to the sfc. This idea already introduced by the previous shift
and will only make little to minor adjustments to ongoing package.
High and mid level cloud cover will thicken acrs the area as the
day progresses and will bank on this to keep highs near the
guidance blend of the upper 60s to lower 70s. Otherwise more
filtered insolation or partly sunny skies could make for another
day where temps breach the warmest of guidance highs in several
areas.   ..12..

.LONG TERM...(Wednesday Night through next Tuesday)
ISSUED AT 313 PM CDT Tue Oct 18 2016

Forecast focus on below normal temperatures late this week then
trending above normal. No significant rain expected for much of this
extended period.

Wednesday night and Thursday: Will maintain small pops as low
pressure rides along a frontal boundary that will be located from
the southern Plains to the Ohio Valley. ECMWF/GFS maintains the idea
of the dvn cwa being on the northern fringe of the larger rain
shield located to our south, where the stronger forcing will exist.
Rain amounts should be a trace to only a few hundredths of an inch
in the dvn cwa. As the day progresses on Thursday the rain chances
should come to an end as the low pressure system tracks into
Pennsylvania. Colder air will be dumped into the Midwest as an upper
level trough digs into the Eastern United States. Highs will be in
the mid 50s to around 60.

Thursday night through Friday night: Rather chilly for the end of
the work week with 850 mb temperatures dipping into the negative
numbers. The center of high pressure will be moving across MO which
should provide mainly clear skies and light winds. This sets up the
potential for frost in portions of the cwa, especially in locations
where the winds can go nearly calm. Lows will dip into the 30s with
highs in the 50s.

Saturday through Monday: Pleasant and dry weather as the upper
flow becomes more zonal, and low pressure tracks well to our north.
Highs will be in the 60s to lower 70s and lows in the 40s.

Monday night and beyond: This could potentially be the start of a
more active weather pattern for much of next week. However, models
differ on the timing. The ECMWF brings the first round of rain on
Wednesday while the GFS already begins this wetter pattern late
Monday night and Tuesday. The consensus models has chance pops
Monday night and Tuesday with likely pops Tuesday night. However, as
of now I have low confidence in this scenario until models have a
more consistent timing. Later shifts can add thunder if needed
depending on amount of instability, but confidence not high enough
this far out.



.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
ISSUED AT 1128 PM CDT Tue Oct 18 2016

High pressure over the plains will keep VFR conditions in place
overnight through Wednesday. Skies will be mostly clear tonight,
with high level cloud cover increasing Wednesday. There is a
potential for very light rain or sprinkles at MLI and BRL late in
the afternoon and evening, which is not included in the forecasts
at this time. Surface winds will remain light from the northwest
to northeast through the afternoon, then increase to 5 to 10 kts
from the north in the evening.




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