Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 180147
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
847 PM CDT TUE MAY 17 2016
Very low dew points across the area this evening should combine
with the clear skies and light winds to bring ideal radiational
cooling conditions. Lows should quickly drop into the 30s after
midnight with many of the favored low areas hitting the lower and
mid 30s. Therefore decided to expand the frost advisory to the
entire forecast area earlier this evening. Areas right along the
Lake Michigan shore should be spared the frost due to warmer temps
and a bit more breeze.
VFR conditions are expected during the TAF period. Winds
generally at or below 10 knots.
Decided to cancel the small craft advisory a bit early due to
winds and waves having diminished considerably from their elevated
status earlier in the day.
.PREV DISCUSSION... /Issued Issued by National Weather Service Chicago IL/
TONIGHT...Forecast Confidence Medium-High
Main concern is with chilly temperatures and frost development
overnight. Surface high pressure will result in light winds and
generally clear skies for much of the area except perhaps the far
southeast. Dewpoints mixing out to the 30s this afternoon should
support lows generally in the mid to upper 30s away from the lake
which will dip to around 40. Can`t rule out a few lower 30s
readings in interior portions of the far northern CWA. These
temperatures should enable at least patchy frost development, with
higher confidence in greater coverage of frost in the western and
northwest CWA. Will be issuing a Frost Advisory from 1am to 8am
CDT for those areas. Have lower confidence farther south and east
due to the potential for some patchy cloud cover moving in
overnight. Evening shift will be able to assess whether advisory
needs to be expanded. Bottom line is to cover or bring sensitive
vegetation indoors tonight regardless of whether your area is in
WEDNESDAY...Forecast Confidence High
The surface high will be centered over the region, resulting in
light east-northeast winds. Expecting any patchy cloud cover in
the south to transition to diurnal stratocu development inland
during the afternoon with partly cloudy to possibly broken
overcast skies. With the expansive and dry surface ridge over the
area, discounting the light qpf painted by the 12z GFS run and
thinking main effect of midlevel energy on back side of departing
trough will be aforementioned cumulus development. Lake shadow
should result in cumulus being scoured out from east to west from
the lakeshore to points inland as lake influence moves inland.
Forecast thermal progs should support highs generally in the lower
to mid 60s inland, with a few upper 60s readings possible in the
far west, namely Sauk and Iowa counties. Persistent onshore winds
look to limit lakeside areas to the lower to mid 50s.
LONG TERM...Forecast Confidence High for the Long Term.
The extended will be dominated by high pressure which will also lead
to a warming trend. 70s are possible away from the lake Saturday
and highs continue to climb into the mid to upper 70s early next
Expecting dry conditions through at least Monday afternoon. The GFS
suggests light rain is possible Friday afternoon and night as a weak
upper level trough and vort streamer push south through the region.
Thinking that the model is over doing atmospheric moisture and
forcing will be lacking so went with a dry forecast. Another
surface high spreads over the region Saturday and then reaches the
east coast Monday night into Tuesday. Showers and thunderstorms are
possible ahead of the next surface low Monday night through Tuesday.
For temps...lows will be in the low 40s Wednesday night and not
expecting any additional frost at this time. Temps will quickly warm
Thursday with highs in the upper 60s away from the lake. On shore
flow will lead to highs around 60 along the lake front. Cloud cover
will probably limit high temps Friday...but thinking Friday will
have very similar temps as Thursday including lake front cooling. We
continue to warm into early next week. Kept lake cooling through the
extended...but lessened the cooling as winds become slightly more
VFR conditions will prevail through Wednesday under high pressure.
Late morning and afternoon cumulus will develop today and likely
again on Wednesday. North-northeast winds will be sustained near
15 kt this afternoon at near lake airports, with gusts to 20 kt at
times. Northeast winds will be lighter on Wednesday.
MARINE...Forecast Confidence High.
Gusty winds and moderate waves will continue into early this
evening so will continue to have a small craft advisory in effect.
Winds and waves diminish overnight and remain light through the
period. High pressure will dominate the forecast and lake breezes
are expected to turn winds on shore each day through the weekend.
WI...FROST ADVISORY from 1 AM to 8 AM CDT Wednesday for WIZ046-047-
TONIGHT/Wednesday AND AVIATION/MARINE...99
Wednesday NIGHT THROUGH Tuesday...99