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Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI
307 PM CST sun Jan 25 2015

Tonight and Monday...forecast confidence...high

Clearing continues to push into the area from the northeast. Latest
mesoscale low level moisture continues the clearing through the
remainder of the the forecast area into late afternoon. While much
of the forecast area may see mostly clear skies this evening and
into the night. May see a little snow develop too...but would likely
be very light...with borderline surface-850 mb Delta T values and
saturation only up to about 3 kft via NAM soundings. Kept lows
tonight milder in the east due to the onshore winds and cloud
potential.

Still expecting another round of light snow on Monday. Overall
forcing looks best in the northwest forecast area in the
morning...with weakening lift through the day. Seeing decent support
for high probability of precipitation via low level q-vector convergence...850-700 mb warm
air advection...and even some upper divergence in the left exit
region of the jet. Model quantitative precipitation forecast has come up a bit...so increased
forecast values. 1000-500 mb thickness values and surface temperatures support
snow to liquid ratios of around 15-17 to 1...resulting in snow
amounts through late afternoon from around a half an inch in the far
southeast...to nearly 2 inches in the far northwest.

One concern is the possible loss of ice Crystal formation beginning
in the west by the afternoon hours. This could result in some
freezing drizzle and also cut down on snow amounts a bit. Soundings
show saturation right up to about -10c...so kind of a tough call.
Mentioned patchy freezing drizzle in the west.

Temperatures aloft are expected to warm through the day tomorrow...so
should still see highs in the upper 20s to near 30 even with the
clouds and snow.

Monday night...forecast confidence is high.

Forcing for mainly light snow will persist into the evening as
short wave energy continues to streak southeast across the area
along the cyclonic side of a strong upper level jet. The forcing
and moisture move off quickly during the evening...so will
steadily decrease probability of precipitation from west to east. The precipitation type is an
issue for all but the far east and northeast parts of the
County Warning Area...so will continue the mention of patchy freezing drizzle. Any
additional snow accumulate would be less than 1/2 inch.

Tuesday and Wednesday...forecast confidence is high.

High pressure builds across the upper Midwest on Tuesday and
lingers long enough to keep US dry through Wednesday. It may be a
dirty high...as we say...with enough clouds around to keep it more
on the mostly cloudy side. But temperatures will still run a bit
above normal.

Thursday...forecast confidence is medium.

The GFS and the European model (ecmwf) are in fairly good agreement in bringing a
fast moving short wave across the area Wednesday night and
Thursday. There/S actually two short waves that merge...one coming
from the Alberta clipper genesis region...the other from the
Central High plains. This helps carve out a digging trough over the
Great Lakes...but the timing puts the better quantitative precipitation forecast off to our east.
And even that isn/T too impressive. For US...we/re looking at quantitative precipitation forecast
numbers around ... nothing of concern at this point. Decent
leading warm advection will push some milder temperatures up here that
puts precipitation type into question again. Will go with a rain/snow
mix Wednesday evening...changing over to all snow later on.

Thursday night and Friday...forecast confidence is high.

High pressure to bring dry weather with temperatures finally cooling down
to levels more normal for this time of year.

Saturday and Sunday...forecast confidence is medium.

Another weak trough passes through bringing small chances for light
snow. Temperatures will be running at or below normal for next weekend.

&&

Aviation/00z tafs/...

Clearing continues to push into the area from the northeast. Latest
mesoscale low level moisture continues the clearing through the
remainder of the the forecast area into late afternoon.

Could see a Little Lake effect snow in the east develop by late
afternoon or early evening. Looks pretty light though and may only
be flurries...so will leave mention out of tafs for now. At the very
least...will probably see some MVFR ceilings return to the southeast.

Will likely see a return to MVFR across souther Wisconsin late
Monday morning and into the afternoon as a shortwave brings another
round of light snow. Snow amounts are expected to be generally
around an inch through Monday evening. Could see closer to 2 inches
in the northwest forecast area where forcing will be stronger in the
morning.

One other concern is the possible loss of ice Crystal formation from
west to east tomorrow afternoon and evening. This could result in
some freezing drizzle and also cut down on snow amounts a little.

&&

Marine...

Wind gusts will ease early this evening...with higher waves
lingering into late evening...so will keep the Small Craft Advisory
going into the evening. Higher waves will persist longer in the
south due to the northeast flow. Lighter winds and subsiding waves
are expected tonight into Monday.

&&

Mkx watches/warnings/advisories...
WI...none.
Lm...Small Craft Advisory until midnight CST tonight for lmz644>646.

Small Craft Advisory until 9 PM CST this evening for lmz643.

&&

$$

Tonight/Monday and aviation/marine...ddv
Monday night through Sunday...Davis

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