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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
607 PM CST Wednesday Jan 28 2015

Update...
issued at 600 PM CST Wednesday Jan 28 2015

Update for adjustments to evening temperature trends following
cooler afternoon highs. Also added some patchy drizzle along with
the low probability of precipitation for light rain overnight. Not expecting freezing
drizzle to be a significant issue...but will have to monitor
northern counties.

&&

Synopsis...
issued at 238 PM CST Wednesday Jan 28 2015

Filtered sun through mostly thin cirrus was over much of the dvn
County Warning Area this afternoon. The snow cover across roughly our NE half was
impacting temperatures despite strong warm air advection.
Southeast to south winds were gusting to 25 to 30 miles per hour. 2 PM
readings ranged from the lower 30s at Dubuque and Freeport to the
middle 40s in our far southern County Warning Area.

Elsewhere...temperatures were in the 70s to lower 80s from eastern
Kansas/western MO into the Southern Plains. A cold front was pushing
southeast into ND where readings were in the 20s. Low pressure was
situated near Sioux Falls. Water vapor loops indicate a short wave
pushing across the northern plains.

&&

Short term...(this evening through thursday)
issued at 238 PM CST Wednesday Jan 28 2015

Forecast focus on a chance of light rain/drizzle tonight.

Tonight...upper level trough swings across the area as low pressure
tracks into eastern/southeast Iowa and then into western Illinois. A cold front
will advance into the County Warning Area after midnight switching winds to the
northwest and increasing to 25 to 30 miles per hour. Operational models paint
some light quantitative precipitation forecast in the form of light rain or drizzle Post frontal
where the airmass becomes saturated below 800 mb. Minimum temperatures
will range from the lower 30s along Highway 20 to the upper 30s south.

Thursday...windy/cold day as low pressure/cold front push off to our
east and 1040 mb high builds into the northern plains. There may
be some very light snow or flurries in the morning mainly east of
the MS river...but no accumulations expected. Tight gradient is
over the County Warning Area much of the day with northwest winds gusting to 35 to
40 miles per hour. As of now expecting winds to remain below Wind Advisory
criteria but later shifts can monitor. Not much rise in temperature
with highs in the middle 30s to around 40.

Long term...(thursday night through wednesday)
issued at 238 PM CST Wednesday Jan 28 2015

The weekend storm system has low confidence on where it will eventually
track. Confidence is high that a storm system will affect parts of
the Midwest.

Dry and quiet conditions will be seen across the area Thursday night
through Friday night as high pressure moves through the Midwest.
Temperatures should average below normal.

Return flow on Saturday will warm temperatures up to around or a
little above normal.

Nearly all the models have sped up the movement of the next cold
front and now bring it through the area during the day Saturday.
Moist is very sparse so only an increase in clouds is expected.
Attention then turns to the approaching storm system.

Recent trends in the models indicate a slower arrival. Thus most if
not all the area should remain dry Saturday through sunset. An
exception may be the far southwest area where some
sprinkles/flurries may develop just prior to sunset.

Saturday night on...
Saturday night/Sunday the main storm system moves through the
Midwest. The models have done a big change from the overnight runs.
The 12z GFS/ECMWF/UKMET are now taking a weaker storm system south
of the area. Extrapolation of the 12z WRF run would suggest this as
well. The exception is the 12z Gem run which brings a significant
winter storm to the Midwest.

As such the model consensus has high chance to likely probability of precipitation for the
area Saturday night and chance to likely probability of precipitation for Sunday.

A majority of the energy that will create this storm is off the
coast of California and is not being sampled by balloon data. Thus
there is a moderate to high probability that the models will undergo
significant swings in potential storm tracks over the next 36-48
hours until the upper level system is on shore and better sampled.

Climatologically...upper level systems that are cut off in the
southwest Continental U.S. Usually...but not always...move out slower than what
the models depict.

Sunday night the model consensus has slight chance probability of precipitation over the
eastern half of the area for lingering snow as the storm system
moves to the East Coast.

The model consensus has dry conditions Monday/Monday night as high
pressure moves through the Midwest. Temperatures should average
below normal.

Starting Tuesday...the models are suggesting a rather active
northwest flow pattern with the potential for several weak systems
spaced 1 to 2 days apart.

As such the model consensus has slight chance to chance probability of precipitation in the
Tuesday through Wednesday time frame with the passage of the first system.

&&

Aviation...(for the 00z tafs through 00z Thursday evening)
issued at 600 PM CST Wednesday Jan 28 2015

Surface low pressure will move across the area overnight. After
the low passes...the wind will quickly increase and switch to
northwesterly. MVFR visibilities and IFR/MVFR clouds will also
accompany the system. Low chances of light rain mainly at
kcid/kdbq overnight...with drizzle more likely.

&&

Dvn watches/warnings/advisories...
Iowa...none.
Illinois...none.
MO...none.
&&

$$

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

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