Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 181751
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1151 AM CST Sat Feb 18 2017

.UPDATE...
ISSUED AT 1150 AM CST Sat Feb 18 2017

11 am temperatures were running near to a degree or two warmer
than yesterday at this time under full sunshine. However, unlike
yesterday, surface winds were much lighter under a weak cold air
advection NW flow aloft behind the very weak low level cool front
that has moved through most of the forecast area. This should
limit highs to much lower than yesterday`s record value, but
readings are still on track to threaten record highs in the low to
mid 60s for this date at MLI and BRL, as referenced in the
climate discussion.

&&

.SYNOPSIS...
Issued at 310 AM CST Sat Feb 18 2017

The latest sfc analysis was indicating a cool front extending
northeast-to-southwest and bisecting the state of IA ATTM, while
a lobe of high pressure jutted down the northwestern plains.
Aloft, a complex Rex block type pattern occupies much of the
CONUS, with cut- off upper low seen on water vapor imagery slow
rolling eastward acrs the southeastern plains/western AR. This
while a S/W trof was digging east-southeast acrs the northern GRT
LKS.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 310 AM CST Sat Feb 18 2017

Today...After some high clouds spill acrs the southern CWA off the
passing upper low to the south, expect another sunny to mostly sunny
day. The weak cool front will continue to sag east-southeast through
the area and almost wash out along and south/east of the CWA by this
evening. Sfc ridging will build in behind it, with a light wind
regime characterizing the day for both processes. This factor should
limit another day of enhanced fire threat, despite ongoing dry mild
weather over plentiful dry dead grass and brush. Back to the mild
part, will raise temps a few degrees from current fcst values.
Although lower thicknesses/bit cooler airmass is filtering acrs the
region from the northwest and weaker sfc wind regime, ongoing dry
boundary layer and full sunshine should warm up again at least to
the warmest of guidance highs(NAM), if not a degree or two warmer in
spots. Will advertise upper 50s to low to mid 60s north of I80, and
mid 60s from I80 on south. A few spots could push the upper 60s in
the more southern areas. Thus most areas near or at record warmth
again, and will be forecasting record highs at MLI and BRL.

Tonight...With light winds, lowered DPTS and dry landscape under
mainly clear skies with passing sfc and upper ridging, we should be
cooler with many areas in the 30s or even upper 20s except in the
far south where will advertise around 40. Again will ignore the
fog signal tonight in the north by the 00z GFS/NAM and later HRRR
runs...too dry of sfc layer.  ..12..

.LONG TERM...(Sunday through next Friday)
ISSUED AT 310 AM CST Sat Feb 18 2017

The evolution of our quiet weather pattern into a fairly busy one
will wait until Sunday night before showing up in the forecast. The
deep southerly flow aloft will bring another remarkable, near record
high forecast for Sunday and Monday before a transition to westerly
flow Tuesday brings a different airmass, but another set of mild
weather for mid week. The end result is a continuation of highs in
the 60s. I cannot express how unusual of an event this is turning
out to be. While colder temperatures appear likely toward the end of
the work week, and some models even indicate snow next week, this
record anomaly is one we will talk about for years to come.

Late Sunday night, the highly amplified upper pattern is expected to
shift east enough to draw in the moist plume that will initially set
up to the west of the CWA Sunday. The cloud cover should combine
with a steady south wind to keep lows very mild, in the mid 40s
northeast to lower 50s central and south. Rain is possible toward
morning, especially in the far southwest. Monday should be a cloudy,
very mild day, with dewpoints surging into the 50s. This will bring
a springlike air mass in over the region, and with that shower and
embedded thunderstorms appear likely from west to east during the
morning to late afternoon east. The moist conveyor will remain
overhead Monday evening, before veering east by Tuesday morning.
Periods of rain showers, with some thunder at times can be expected.
Most locations should see light amounts of rain, but some patchy
amounts around 0.50 are possible.

Tuesday, dry air from the plains will sweep in, with west winds and
sunshine helping boost afternoon highs to the upper 50s north to mid
60s far south. The westerly flow will become southwest by Wednesday
a broad upper trof builds into the lower Rockies. The GFS and ECMWF
differ on how far south a weak front will drop for Wednesday, and
this is resulting in a forecast of upper 50s north the upper 60s
south. If the slower ECMWF is correct, and that is entirely possible
given the zonal to southwest flow aloft, highs could end up begin
several degrees warmer that this. This would put yet another day in
play  for record highs for Wednesday.

The broad western upper trof is expected to spread cyclogenesis into
eastern Colorado by Thursday. The frontal position which is
initially dry for Wednesday into Wednesday night for our CWA, will
become a focus for the what could be an intense cyclone track late
this week. This systems warm sector will no doubt feature
thunderstorms, while locations well to the northwest of our area may
be risk for a wind driven snow. Any snow chances for our region will
have to wait until the occluded low moves by Friday when much colder
air sweeps in behind the low. Following this lows passage, a
temporary cool down is forecast before another wave of low pressure
develops early in the week. Weather this system passes to the south
far enough for snow will not be certain for some time yet.
ERVIN

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
ISSUED AT 1150 AM CST Sat Feb 18 2017

VFR conditions will continue under clear skies and light winds as
high pressure moves across the region. Some forecast models are
depicting late night and early morning fog, especially at CID and
DBQ. These models appear to be initializing with too much low
level moisture and are thus overdone with their depiction of fog.

&&

.CLIMATE...
ISSUED AT 307 AM CST Sat Feb 18 2017

Record Highs for Today February 18th...

Moline.........63 in 1913
Cedar Rapids...65 in 1981
Dubuque........61 in 1981
Burlington.....65 in 1913

Record Highs for February 19th...

Moline.........69 in 1930
Cedar Rapids...68 in 1930
Dubuque........63 in 1930
Burlington.....70 in 1930

Record highs for February 20th...

Burlington.......67 in 1983
Cedar Rapids.....60 in 1981 (and prev years)
Dubuque..........61 in 1981
Moline...........65 in 1930

&&

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

$$

UPDATE...Sheets
SYNOPSIS...12
SHORT TERM...12
LONG TERM...Ervin
AVIATION...Sheets
CLIMATE...Ervin/12



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