Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Milwaukee/Sullivan WI
959 PM CDT Friday Oct 31 2014
Pressure gradient continues to relax as high pressure builds into
the region. Still getting gusts to 30 knots/34 miles per hour/ along the lake
from Milwaukee south. North-northwest winds along the lake which earlier kept
the convergence zone...and subsequently the lake-effect showers
offshore...are beginning their forecast shift to the NE. Expect
the lake-effect bands to continue to push onshore from Sheboygan
to Kenosha counties overnight...and inland as far as far southeast
Waukesha and far southeast Walworth counties. Looks to be a mix of
rain and snow showers...going over to all snow showers after
Gusty winds will continue to lower as high pressure builds into
the state...though gusts to 30 knots through midnight at kmke and
kenw. Lake-effect snow/rain showers beginning to work inland as
winds come around more to the north-northeast...with kmke and kenw the best
bet to see visibility-reducing snow showers. Accumulations will
remain below 1/2 inch...mainly on grassy areas...but surface temperatures
will have to be watched overnight as temperatures fall below freezing.
Will keep Gale Warning for all zones going until 06z. Pressure
gradient relaxing from north to south as high pressure builds
into the state...with gusts at the Sheboygan C-man only reaching
30 knots last hour. Should see a continued slow diminishing of
both sustained winds and gusts into the early overnight. Waves
will remain high..and with winds holding at 15 to 25 knots with
gusts to 30 knots into the overnight...will need a Small Craft
Advisory after the Gale Warning ends....that could go into
Previous discussion... /issued 342 PM CDT Friday Oct 31 2014/
Tonight and Saturday...forecast confidence high.
The potent upper level shortwave trough over Lake Michigan
responsible for the windy Friday will shift east overnight. Surface
winds will remain northerly but gradually diminish through the late
afternoon and evening as surface high pressure builds into the upper
Midwest. The Wind Advisory expiration time of 6 PM is reasonable.
It will be a cold night. The stratocumulus clouds over the area this
afternoon will rapidly dissipate late this afternoon. Winds will
remain elevated through the evening... so wind chill temperatures will be
in the 20s and then drop into the teens overnight. 925mb temperatures will
be around -3c with a weak inversion yielding min temperatures in the lower
to middle 20s inland. Clouds over the Lakeshore counties will keep
temperatures milder there.
Lake effect showers in multiple shore-parallel bands have remained
just offshore of Racine and Kenosha counties for most of the
afternoon. 1000-850mb winds will veer to the northeast overnight
which should push the lake effect snow bands inland from Milwaukee
south to Kenosha. Light accumulations of an inch or less will be
possible. The most likely time period for snow showers to occur will
be midnight through 4 am.
1000-850mb winds will remain northeast with moderate relative humidity through
midday Saturday before turning back to the north and drying out.
This will keep at least lake effect clouds inland over Racine and
Kenosha counties with possible light snow showers. Meanwhile...
surface winds will become light and shift from northeast to
southeast through the afternoon. There will be plenty of sunshine.
However... 925mb temperatures will barely rise to 0c... so highs will only
be in the lower 40s.
Saturday night through Sunday night...forecast confidence is
High pressure will slide east by Sunday morning. Temperatures should
still radiate out pretty hard Saturday night...especially across
the east. Some increasing clouds and winds will keep temperatures a bit
more elevated west.
Other than some high clouds...Sunday and Sunday night will still
be quiet. A tightening pressure gradient due to high pressure east
and low pressure pushing in from the west will bring gusty
southerly winds on Sunday. All those leaves that moved south
today...will move north on Sunday...
Monday through Tuesday...forecast confidence is high.
Overall...Monday will be another quiet day. The trough approaching
from the west will pull moisture north that could produce some
showers just ahead of an associated cold front later Monday
afternoon...and mainly west of Madison. Some of the models bring
it into the southeast during the afternoon...but that looks
dubious given the moisture profiles.
The bulk of the forcing and moisture will arrive with the trough
Monday night. Rain is likely during this time and the trough should
be exiting the east right around 12z Tuesday. Will hang onto a
chance of rain into Tuesday...but that may get trimmed out over
time as the models appear to picking up speed with this system.
They were rather slow on the previous run. Won't make a drastic
adjustment at this time however.
Wednesday...forecast confidence is medium.
A quick hitting clipper type system will race through later on
Wednesday...possibly into Wednesday evening. This could bring a
shot of some light rain.
Thursday and Friday...forecast confidence is medium.
High pressure returns...bringing quiet weather. The end of the
week is looking cooler...but nothing drastic.
The strong winds and gusts will gradually diminish through the
evening... remaining elevated in the Lakeshore counties. Drier air
will spread into the region tonight as high pressure approaches.
Skies will clear inland quickly late this afternoon. Lake effect
clouds and scattered light snow showers will linger through tonight
and possibly Saturday morning from Milwaukee south through Racine
and Kenosha. MVFR ceilings with another 0.5 to 1 inch of snowfall on
grassy areas is possible at Racine and Kenosha. Mke has a good
chance for MVFR ceilings from 06z to 12z as well.
Gale Warning remains in effect until 06z Saturday across the
nearshore waters of Lake Michigan. The low pressure system over the
eastern Great Lakes will gradually shift east overnight and high
pressure will spread into the upper Midwest on Saturday. Gales and
high waves will diminish to small craft conditions through the
Waves will slowly subside below 4 feet by Saturday evening. Thus...a
Small Craft Advisory will be needed into Saturday evening after the
Gale Warning expires.
Lm...Gale Warning until 1 am CDT Saturday for lmz643>646.
tonight/Saturday and aviation/marine...mrc
Saturday night through Friday...Davis