Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 171159
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
659 AM CDT Fri Mar 17 2017

...12z AVIATION UPDATE...

.SYNOPSIS...
Issued at 330 AM CDT Fri Mar 17 2017

The latest sfc analysis was indicating a wave acrs southwestern IA,
with associated warm front extending southeastward along and just
south of the DVN CWA into southern IL. Aloft, the driving vort max
of the sfc system was noted in steering west-northwesterlies pushing
east out of western into central IA ATTM. This system producing
sctrd showers acrs the area, and enough elevated instability plume
of 200-300 J/KG MUCAPES to produce some embedded thunder out there
attm. Would not be surprised if a more developed thunderstorm even
produced some pea size hail early this morning in some spots.
Another larger upper wave was noted digging southeastward acrs
Manitoba.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 330 AM CDT Fri Mar 17 2017

Today...Will walk out sctrd showers and embedded thunder eastward,
with most of it out of the CWA by 1430z to 15z this morning. Most
latest run HiRes models agree with this timing. Then with clearing
skies and plume of mild air drawn up by the wave during the midday
and afternoon, will have highs in the 50s to lower 60s acrs much of
the area. Passing sfc trof and wave will veer the llvl winds to the
west and increase them to 10-20+ MPH with higher gusts during the
same time frame, but some lag in cool advection by this flow until
late in the day.

Tonight...As the above mentioned trof acrs central Canada digs down
acrs the GRT LKS tonight, 1030+ MB sfc ridge will dump down the
plains and acrs the MO RVR Valley into early Sat morning. But llvl
cyclonic flow expected to hang on locally acrs the mid and upper MS
RVR Valley, and portion of -3 to -7C H85 MB cold pool to clip down
acrs the CWA on nose of northwesterly 40 KT LLJ. Portion of cold air
advection stratocu deck also to make it down acrs at least the
northeast half of the CWA overnight, and would not be surprised if a
few flurries get wrung out of it especially in northwestern IL.
but for now will keep the fcst dry tonight. Despite clouds and
lingering wind, will go with chilly lows in the upper 20s to lower
30s for most of the CWA.   ..12..

.LONG TERM...(Saturday through next Thursday)
ISSUED AT 330 AM CDT Fri Mar 17 2017

Overall near seasonable mid March Weather with a couple of light to
moderate precipitation events.

Long Term Forecast Confidence Assessment...fair or average with
significant variances in rain shower and isolated storms late Sunday
and again Thursday & Friday. Limited instability currently doesn`t
suggest a significant severe risk at this time.   Area highs/lows
mostly within 5 degrees of forecast.

Saturday & Saturday Night...weak high pressure to produce slightly
below normal temperatures with fair skies and light winds.  Highs
upper 40s to the lower 50s with lows mid/upper 20s to lower 30s.

Sunday...Warmer with increasing south winds and continued fair
skies.  Highs in the 50s to lower 60s south.

Sunday night and Monday...passing front with weak upper forcing and
no surface based instability supports only chance showers and
isolated thunder with light precipitation amounts ending early
Monday.  Lows in the 40s with highs Monday in the 50s to lower 60s
south sections.

Monday night through Thursday...return to slightly below normal
temperatures and fair skies with next Canadian high pressure passes.
Highs mostly in the 40s to the lower 50s south with lows 25 to 35.

Thursday night through Friday...more significant disturbance
supports decent precipitation event with large variances in timing
and location of surface low track for low confidence. Majority of
tracks take low to our south not suggestive of severe risk attm
though low WBZ of 8-9K AGL suggest small hail is reasonable.
Temperatures support highs in the 50s to lower 60s with lows mostly
in the 40s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
ISSUED AT 645 AM CDT Fri Mar 17 2017

Most showers and some storms east of the TAF sites now, but
lingering MVFR CIGs through mid morning before clearing from the
west. Will have to watch the upstream low stratus deck now over
MN and far northwest IA, as it tries to push east and impact the
CID and DBQ sites by this afternoon. If it does, it should
diurnally raise to MVFR levels from the IFR CIGs it is currently.
Winds veering to the west-northwest by this afternoon and increase
to 12-20 KTS with higher gusts, and maintain 10-15 KTS overnight.
A good chance a MVFR cloud deck will then push south out of the
upper MS RVR Valley and down acrs the TAF sites from mid evening
and into the overnight. Low confidence that it will make it down
to the BRL site.  ..12..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...Nichols
AVIATION...12



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