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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
1126 PM CST Wednesday Mar 4 2015

issued at 536 PM CST Wednesday Mar 4 2015

Early evening update to add some isolated snow showers across the
far west. Diurnally driven convective snow showers in central Iowa
have reduced visibilities down to 1/2 for brief periods during the
late afternoon. Radar trends indicate some of these weakening snow
showers may skirt the far western forecast area for the next 1-2
hours. change to forecast lows and wind chills
tonight. Will continue to monitor cloud/wind trends this evening
as northwest counties may approach Wind Chill Advisory criteria.


issued at 257 PM CST Wednesday Mar 4 2015

12z upper air analysis has an 850mb low over southwest Oklahoma with an
850mb front running from the low into the Ohio Valley. A secondary
850mb Arctic front ran from Eastern Lake Superior into central South
Dakota. Satellite trends through middle afternoon show plenty of middle
and high level clouds from the system passing to the south with
diurnal clouds associated with a weak disturbance from Iowa back
into the northern plains.

18z surface analysis has the Arctic high over the central and northern
plains with the fronts associated with the main storm system from
Texas into the Tennessee Valley. Several weak troughs ran from the
western Great Lakes into Minnesota. Dew points were in the single
digits above and below zero from the Great Lakes into the northern
plains with 20s and higher from the Ohio Valley into the Southern


Short term...(this evening through thursday)
issued at 257 PM CST Wednesday Mar 4 2015

The Arctic high will slowly build into the Midwest tonight and
Thursday keeping temperatures 20 to 25 degrees below normal.

The weak disturbance moving into western Iowa is generating isolated
flurries per observations. In some cases the flurries are not quite
reaching the ground per the 20z dsm observation.

The diurnal clouds across Iowa/Minnesota will slowly dissipate with sunset
but some will still get into the area. The overall support for
flurries will also weaken as well. However...the possibility does
exist that a couple of flurries may occur across the western third
very late this afternoon and early evening. For a vast majority of
the area dry and cold conditions will be seen.

The Arctic air mass will allow temperatures to drop below zero
tonight. Based on projected lows and winds...a Wind Chill Advisory
would be needed from 4 am to 9 am for areas along/north of I-80 and
west of the Mississippi. However...satellite trends suggest the
possibility of high level clouds overnight. If this occurs...low
temperatures could easily be 3-5 degrees warmer which would keep
wind chills above the threshold of 20 below zero.

Therefore...will issue an Special Weather Statement to highlight the cold conditions and
let subsequent shifts monitor cloud/temp/wind trends to see if an
advisory would be needed.

Long term...(thursday night through wednesday)
issued at 257 PM CST Wednesday Mar 4 2015

Forecast focus on warming temperatures through the extended with
little if any precipitation for at least the next 7 days.

Thursday night through this weekend...northwest flow aloft still
evident on the GFS/European model (ecmwf) with a series of disturbances moving
through the flow. The bulk of the forcing and quantitative precipitation forecast is shown to stay
north of the dvn County Warning Area...but could graze our far northern County Warning Area. For now
will continue to stay with the dry look. Temperatures will gradually
improve each day...with highs in the lower 30s to lower 40s on Friday
warming to highs in the upper 30s to upper 40s by Sunday. However...
minimum temperatures will be in the 20s. Each day we will be melting
more and more of the snow pack.

Monday through Wednesday...upper flow becomes zonal but high
pressure ridge across the southern states will block Gulf moisture
from being transported this will be a dry period. The
result will be a noticeable jump to Spring-like temperatures next
week with much of the snow pack completely gone by then. Maximum
temperatures will soar well into the 50s to lower 60s with lows in
the 30s. However...some of the models are even warmer than this with
highs in the 60s! For now I will stay on the conservative side.


Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1124 PM CST Wednesday Mar 4 2015

Low VFR ceilings will persist into the early morning hours at kbrl
before clearing with an isolated flurry not out of the question.
Otherwise...expect VFR conditions with a west/northwest breeze under 10 kts.


Dvn watches/warnings/advisories...


Update...rp Kinney
short term...08
long term...haase
aviation...rp Kinney

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