Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 182110

Area Forecast Discussion
National Weather Service Quad Cities IA IL
310 PM CST Sat Feb 18 2017

ISSUED AT 310 PM CST Sat Feb 18 2017

Another very mild day for late February with widespread temperatures
in the 60s early this afternoon under clear skies. Record highs in
the lower to mid 60s have been set or tied at Moline, Dubuque and
Burlington. At 20z, MSAS analysis indicated high pressure centered
over northwest IA/southwest MN while a very weak cool front had
pushed through the forecast area, reaching from roughly Chicago to
Kansas City. This was resulting in very light northwest to north
winds over the forecast area and shallower mixing into cooler air
aloft that will prevent a repeat of the widespread 70s seen
yesterday. Aloft, an upper low was passing just to the south through
the mid MS Valley toward the Ohio River, while a sharp ridge was
just upstream from TX into the northern Rockies. This ridge was
being amplified by a digging upper trough moving into Baja CA.


.SHORT TERM...(This Evening through Sunday)
ISSUED AT 310 PM CST Sat Feb 18 2017

Temperatures are the primary challenge as the dry and unseasonably
mild air will remain in place under the advancing western ridge

Through the rest of the afternoon, temperatures in the mid and upper
60s with dewpoints only in the lower 30s are resulting in relative
humidity values in the 30s and even 20s in some spots. While these
values are typically favorable for grass fires due to the dry
conditions, the lack of significant wind to spread any fires that
start is keeping the grassland fire danger index relatively low.
Thus, fire weather conditions are not as elevated as yesterday.

Overnight, skies will remain clear with light winds and dry
air allowing temperatures to cool back to lows similar to this
morning, from the lower to mid 30s central and north across the
north. The south, however, will be a bit cooler than the previous
night, in the upper 30s to lower 40s, due to the slightly cooler low
level airmass. Will continue to downplay the short term high res
model output suggesting late night and early morning fog, as these
models appear to have too much low level moisture, based on
initialization/verification and dewpoint trends this afternoon.
Areas of higher moisture, indicated by surface dewpoints showing up
in the upper 30s to lower 40s closer to the lingering snowpack well
to the north should instead condense out as dew or frost.

Sunday is shaping up to be another day of record to near record
warmth with highs well into the 60s. With a similar airmass in place
as today, thickening high level cloud cover and light southeast
surface winds will be the only limiting factors that could hold
temperatures back from exceeding the records listed in the climate
section below.

.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 310 PM CST Sat Feb 18 2017

Forecast focus on continued well above normal temperatures with more
record highs in jeopardy through mid week. Pattern similar to what
you would expect in March or even early April.

Monday and Monday night: Low pressure tracking well to our north
will send a surface trough across the cwa. PWAT`s increase to about
1.30 inches and with forcing associated with an upper level trough,
there should be a band of showers and a few thunderstorms. Deep
layer shear appears moderate to strong but SBCAPE is minimal due to
extensive cloud cover. As of now, SPC has general thunder over the
cwa but if instability becomes greater then this may be upgraded.
The precipitation should end Monday night from west to east. Highs
should be in the 60s with the potential for record highs, despite
the cloud cover.

Tuesday through Wednesday:  More record highs expected and
temperatures could be much warmer than currently forecast. There
should be plenty of sunshine both days with highs on Tuesday in the
60s. If the ECMWF is correct, with its warmer 850 mb temperatures on
Wednesday, highs in the lower to mid 70s cannot be ruled out.
The set-up seems similar to yesterday with low pressure tracking
across the upper Midwest and southwest winds. Also, will need to
keep an eye on conditions suitable for grass fires.

Thursday through Friday: Very interesting weather pattern with an
intense cyclone tracking from the southern Rockies into the Midwest.
This will pull very warm to hot temperatures into the southern
Plains with cold temperatures situated across the northern tier of
states. A strong warm front will lift into the dvn cwa on Thursday
and Thursday night with the potential for showers and thunderstorms.
On Friday the low pushes across the cwa with heavy snow to our north
and strong thunderstorms ahead of the strong cold front, depending
on instability, but deep layer shear appears strong. Too early for
specific threats at this time.

Friday night and Saturday: Winter returns with the possibility of
accumulating snow but once again too early for details. However,
temperatures will be more typical of February, with highs in the 30s
and lows in the 20s. Of course, this will come as a shock after
quite the string of record highs.


.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.


ISSUED AT 310 PM 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




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