Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Milwaukee/Sullivan WI
318 PM CDT Thursday Apr 17 2014
Tonight and Friday..forecast confidence...high
Based on model 925 mb relative humidity...it looks like clouds may hang on into the
evening and early night longer than originally expected. These
clouds will help keep temperatures from falling too fast...though less
clouds and light winds by morning will still result in lows in the
low to middle 30s.
Skies will be mostly sunny to partly cloudy on Friday with high
pressure overhead. Warmest temperatures aloft will be in the southwest
tomorrow...with highs into the middle 50s expected. It will be cooler
toward the northeast...and especially all areas near Lake Michigan
under onshore winds.
Friday night and Saturday...forecast confidence is high.
The high will slide east Friday night with a weakening trough/cold
front approaching from the northwest later Saturday. This should
be a dry period with chilly temperatures expected Friday night under a
dry airmass and light winds. Warm advection really gets going on
Saturday as southerly winds increase ahead of the approaching
trough. Unfortunately...the far east near the lake will probably see
a southeast component to the wind hang in through the day...keeping
it much cooler near Lake Michigan...especially up around the
Sheboygan area. Temperatures will likely range from the upper 60s
southwest of Madison...to the upper 40s in Sheboygan.
Saturday night and Sunday...forecast confidence is medium.
The surface trough/cold front will try to drift south through the
forecast area...but the new models are trending toward the trough
getting stuck over the northern forecast area and not penetrating much
farther south. The trough extends from a parent low that moves
across southern Canada...into another developing low pressure
system over the Southern Plains. As a result...there isn/T much
of a southern push to the front. This should keep the bulk of any
precipitation located north of Milwaukee and Madison. The low level
thermal ridge is therefore much stronger across the area than
previously thought so temperatures have been raised. We should see
offshore winds along the lake on Sunday...except maybe the
Sheboygan...so much of the County Warning Area should enjoy a warm day on Sunday.
Sunday night and Monday...forecast confidence is medium.
The low pressure system over the Southern Plains will move through
the area late Sunday night and Monday. The GFS and the European model (ecmwf)
differ on strength of the surface low...but they both show a decent
middle level short wave pushing through. So precipitation chances are pretty
high for this period. Soundings still look pretty stable with
respect to convection...so no thunder mentioned. Temperatures will be
tricky on Monday with precipitation/clouds and an onshore flow kicking in
by afternoon in the wake of the passing low.
Tuesday through Thursday...forecast confidence is medium.
High pressure should keep things dry for Tuesday with highs away
from the lake hitting the middle 60s. A decent onshore flow will keep
lake area quite chilly.
Strong low pressure approaches the area later Wednesday through
Thursday. Some leading warm advection showers are possible later
Wednesday afternoon and night...but it will be struggle against
some low level dry air. The moisture advects in much better on
Thursday with precipitation chances increasing.
A few locations are still holding onto MVFR ceilings...but ceilings are
generally expected to be VFR across the area by late afternoon. VFR
clouds will probably hang on into the evening...slowly decreasing
late evening and overnight as high pressure approaches. Partly
cloudy to mostly sunny skies are expected Friday.
Waves will continue to subside into this evening...with fairly quiet
weather expected the next few days.
Tonight/Friday and aviation/marine...ddv
Friday night through Thursday...Davis