Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KDVN 101624

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1024 AM CST Tue Jan 10 2017

Issued at 956 AM CST Tue Jan 10 2017

Hoisted wind advisory across the CWA for this afternoon and
evening for westerly gusts of 40 to 50 mph. Thinking strongest
winds will occur across the NE half of the forecast area along
track of 3 hr isallobaric/pressure tendency max of near 10mb/3
hr. In addition to the rapid sfc pressure change this afternoon
and evening, strong low-level cold air advection will result in
efficient boundary layer mixing into 45-50 kt winds near 900mb.

The deepening sfc low has pumped mild and unstable air northward
into far eastern Iowa and all of western Illinois. Currently,
there are a few isolated lightning strikes between Muscatine and
Burlington. So will add slight thunder chances to the forecast to
account for this potential.

Mature deformation zone and 850-700mb frontogenesis will continue
periods of light to moderate rain through the afternoon. As
thermal profiles cool toward the early to mid afternoon, a
changeover to a rain/snow mix and eventually all snow is
anticipated across the NW CWA; most likely NW of a Cedar Rapids to
Dubuque line. Minor accumulations of a dusting to a half inch are
possible, especially along/NW of a Vinton to Manchester line.


Issued at 330 AM CST Tue Jan 10 2017

At 3 AM CST...area is under strong warm air advection with temperatures
all above freezing with lower 40s along and south of the I-80 corridor.
No precipitation is occurring with moderate south winds of 10 to 20
MPH with some gusts to 25 MPH. An intensifying surface low pressure
system will move into central Wisconsin this afternoon with windy conditions
and much colder air arriving by mid to afternoon. Strong pressure falls
supports rain to blossom in eastern Iowa by daybreak as surface low
pressure system moves northeast.


.SHORT TERM...(Today and Tonight)
ISSUED AT 330 AM CST Tue Jan 10 2017

Short term forecast confidence assessment...fair or average. Concerns
are how high winds get by afternoon and if any accumulating snow
in far NW sections this afternoon does occur. Current analysis
supports winds near but below wind advisory across the region with
later shifts to assess as to how strong the surface low

Today...areas of light to locally moderate mostly morning rain expected
over mostly the northern 1/2 of the region this AM with breezy south
winds and temperatures rising into the 40s all but far NW and lower
50s far SE by late morning. As surface low moves northeast winds will
shift to the west and northwest at 20 to 25 MPH with gusts of 35 MPH
and isolated gusts around 40 MPH possible by early to mid afternoon.
Assess risk of a wind advisory over portions of the region at about
1 in 3 with speed of low pressure intensification and amount of latent
heat with precipitation next 8 to 10 hours keys to clarify this question.
Local techniques suggest far NW counties or west of a DBQ to CID line
may see some snow with Benton and Buchanan counties maybe picking up
a half inch of wet snow before ending by mid afternoon. Highs
will show a tight gradient with upper 30s far NW to lower 50s SE
sections. Temperatures will fall rapidly after front passes across
the area from west to east from 11 AM to 4 PM.

Tonight...partial clearing and much colder as westerly winds diminish
to 10 to 15 MPH by late evening as high pressure moves in. Area lows
should range from the upper teens far NW to upper 20s far SE sections.

.LONG TERM...(Wednesday through next Monday)
ISSUED AT 330 AM CST Tue Jan 10 2017

Wednesday...The next wave/sfc low is still progged to ripple east-
northeastward along llvl baroclinic ribbon adjusted from acrs the
southern plains...up through the northeastern GRT LKS this period.
Thus with associated isentropic lift along the thermal ribbon, the
next round of precip for the local area still appears to be on
track for Wed afternoon and into the evening. SREF type low to mid
level thermal profiles and large temp contrast/gradient from
northwest-to-southeast and the south, suggest the precip to be
mainly rain southeast of a Freeport IL, to Cedar Rapids IA, and to a
Marengo IA line during the afternoon...with sleet and freezing rain
to the northwest.

The 00z models suggest precip appears will be on the light side
during the afternoon with much of initial lift going into saturation.
Another seasonably mild day in the 40s acrs the southeastern half to
2/3`s of the CWA, with a few of the milder models such as the new 00z
ECMWF suggesting several areas along and south of I80 nearing or
surpassing 50 degrees. This while areas northwest of CID may not get
out of the low to mid 30s. Will play high temps more conservatively
for now. Any afternoon icing potentail Wed afternoon looks marginal.
Wed night, with wave passage the llvl cold conveyor will increase with
cooling at the sfc layer above lingering warm moist wedge aloft. This
may make for a southward creeping sleet and freezing rain swath from
acrs the northwestern third of the CWA and toward I80 as Wed evening
progresses. Sfc temps and WBZ`s may be marginal while it is still
precipitating, but there may be a chance for at least a light glaze
from the Sigourney/Washington IA areas...northeastward through and
north of the Quad Cities...CID/DBQ areas and points east into NW IL.
Then expect precip to wind down and become spotty into the overnight
hours and early Thu morning. Several model solutions thing bring a
secondary bout of Isentropic lift along deepening llvl cold pool
fro a round of flurries or light snow acrs the northern third to
half of the CWA late Wed night into Thu morning, while the far
southeastern CWA may still be subject to an overrunning wintry mix
through at least 14-15z Thu. A complex 24 hours for sure and time
for the models to still change north or south thermal ribbon
adjustment over the next 24 Hrs.

Thursday into Friday....After what ever precip lingers into Thu
morning, re-enforcing dome of Canadian High pressure pushing down
acrs the northern plains and upper Midwest to make for a mainly dry
but cold end to the week locally. Lows by Fri morning will be in the
low single digits or close to zero even with limited to little/no
snow cover...low to mid teens(10-15 degrees) south of I80.

Friday night through Monday...As expected, the various latest run 00z
medium range solutions continue vary in handling and phasing bouts
of wave energy ejecting out of southwestern CONUS L/W trof and up
toward lingering llvl high pressure complex acrs the upper MS RVR
valley and GRT LKS this coming weekend. The 00z GFS generally still
would have a plume of mainly light snow moving acrs the area after
midnight Fri night through early Sat afternoon, but with a
transition to sleet and freezing rain along and south of I80 by
daybreak Sat morning. In contrast, the new 00z ECMWF has just some
non-significant light snow or flurries with initial elevated WAA lift
later Fri night, then is largely dry for the CWA until Sunday

The main show advertised by the latest Euro is actually late Sunday
night and Monday, with the system now advertised by this model to
pull out further west so that after an initial leading edge of sleet,
snow and freezing transitions to mainly all a cold rain
Mon into Mon evening for all except maybe the far northwestern CWA.
The 00z GFS has adjusted a bit wet as well, but still would produce
plenty of ice and sleet acrs the northwestern half of the CWA Sunday
night into Mon, with mainly rain in the southeast. So to say the
least at this juncture in the game, model confidence remains low and
will keep mainly moderate to high CHC POPs for snow north, and wintry
mix south and east late in the extended. It may take another 48+
hours of model runs to start to have some confidence of what is
really going to happen this weekend and into early next week as the
main upper wave moves in off the eastern Pacific and gets better
sampled.    ..12..


.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
ISSUED AT 543 AM CST Tue Jan 10 2017

Generally MVFR/IFR conditions with areas of rain and breezy south winds
of 10 to 20+ MPH through 10/17Z. A strong, fast moving cold front will
pass through the terminals by 10/19Z bringing MVFR conditions and windy
west winds of 20 to 35+ MPH. After 11/01Z VFR conditions with partial
clearing skies and west winds 5 to 15 MPH becoming light and variable
after midnight.


Issued at 330 AM CST Tue Jan 10 2017

The pool of water from a significant ice jam flooding continues on
the Mississippi River from Keithsburg through Burlington and just
downstream. Stages are generally forecast to remain steady or slowly
fall at BRL and GLD, where moderate and minor flooding is continuing
respectively. At Keithsburg, well upstream, is continuing to see
rises above the action stage there, and will need to be watched for
flood potential in the next 24 hours if the downstream jam does not
decrease. Reports continue to show that the ice was jamming on the
west side channel from around the confluence of the Skunk River up
to just south of Burlington where it was backing up. The east side
of the river and east channel downstream of Burlington was reported
open. There may be further fluctuations in all levels up and
downstream of the jam in the next 24 to 36 hours, especially with
onset of milder weather. Other tributary rivers such as the Rock
River will also have to be watched for ice action induced sudden
fluctuations in river stage levels, with the bout of milder weather
today and again on Wednesday.


IA...Wind Advisory until 10 PM CST this evening for Cedar-Clinton-

     Wind Advisory until 7 PM CST this evening for Benton-Buchanan-
     Des Moines-Henry IA-Iowa-Jefferson-Johnson-Keokuk-Lee-Linn-
     Van Buren-Washington.

IL...Wind Advisory until 10 PM CST this evening for Bureau-Carroll-
     Henry IL-Jo Daviess-Mercer-Putnam-Rock Island-Stephenson-

     Wind Advisory until 7 PM CST this evening for Hancock-Henderson-

MO...Wind Advisory until 7 PM CST this evening for Clark-Scotland.



SHORT TERM...Nichols
HYDROLOGY...12 is the U.S. government's official web portal to all federal, state and local government web resources and services.