Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 211432
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
932 AM CDT Fri Apr 21 2017

.UPDATE...
Partly cloudy to overcast skies will prevail through the morning.
They may mix out somewhat this afternoon but the upper trough will
linger over the region. Drier air with high pressure will move in
tonight.

&&

.MARINE...
Will allow the small craft adviosry to expire at 10 am. North-
northwest winds will become northeast this afternoon. Gusts will
gradually subside through the day.


&&

.PREV DISCUSSION... (Issued 300 AM CDT Fri Apr 21 2017)

TODAY AND TONIGHT...Forecast confidence is high.

Surface high pressure is building into the area from the
northwest. Aloft we still have a sharp mid level trough drifting
across the area at midday. This should help to keep things mostly
cloudy across the area at least into the early afternoon. There is
some clearing across the west early this morning, but the cold air
aloft and the trough should conspire to fill that back in with
normal diurnal trends. Subsidence and drying in the wake of the
trough, coupled with loss of heating will allow things to clear
out tonight. Northeast winds by Lake Michigan will keep it cooler
there vs west of Madison today. Lower dewpoints, light winds and
clearing skies will provide radiational cooling tonight, pushing
lows down into the mid 30s tonight. Those temps are low enough and
we are starting to get stuff growing, so mentioned patchy frost.

SATURDAY THROUGH MONDAY - Confidence...High
Pleasant weekend shaping up as high pressure dominates. The 925
moderates a bit each day this period though onshore flow will be
noticeable over the weekend keeping things cooler in the east. On
Monday a low draws closer from the Plains setting up a more
southerly component though lake areas still trending cooler with a
bit of an onshore component noted.

MONDAY NIGHT - Confidence...Medium
A lead negatively tilted shortwave traverses the area Monday
night. This will interact with an 850 jet max that passes to our
northwest. This leads to better lower level dynamics/moist
advection staying to our north with only gradual moisture influx
into the area with our area more influenced by entrance region of
850 jet max. Will have a chance going though latest GFS and GEM

TUESDAY - Confidence...Medium
With low pressure passing to our north a cold front will extend
into southern WI and may generate a few shra. However some
indications that the better precip potential remains to our south
or southwest.

TUESDAY NIGHT - Confidence...Medium
A wave of low pressure is expected to ride along the front and
spread better rain chances into the area. The GFS is showing
higher QPF in a more focused area than the GEM and ECMWF.

WEDNESDAY - Confidence...Low to Medium
There is agreement between the GFS and ECMWF that high pressure
will nose in and shift the focus for precip to our south.
Meanwhile the GEM keeps the focus across WI with a higher
amplitude 500 millibar trough/ridge pattern set up across the
western/central US.

WEDNESDAY NIGHT AND THURSDAY - Confidence...Low to Medium
It continues to be the GFS and ECMWF vs. GEM solution with respect
to the position of the frontal boundary and precip trends. The
GFS/ECMWF gradually lift the frontal boundary northward from the
mid Miss Vly and expands the frontal precip northward into the
area by Thursday while the GEM retains a more northeast/southwest
oriented front and a much more northern situated surface low in
our area Wednesday night and Thursday. Bottom line is that there
is for now at least a better consensus of the ECMWF/GFS solution
with the best rain chances Tuesday night and then again on
Thursday.

AVIATION(06Z TAFS)...A few light rain showers or drizzle may clip
northern portions of the area for the next few hours. Otherwise,
ceilings should gradually lower to around 1500 to 2000 feet above
ground level by 09Z Friday, with lower ceilings moving southward
into the area. These should linger into Friday morning, before
rising and mixing out by afternoon.

Gusty west northwest winds should linger overnight, before slowly
weakening and becoming north to northeast. Some gusts to 15 knots
are possible in the afternoon.

MARINE...The small craft advisory remains in effect through 10 am this
morning due to continued gusty northwest winds. Look for the winds
to gradually subside through the day, veering to the northeast
during the afternoon.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory until 10 AM CDT this morning for LMZ643>646.

&&

$$

Update...Marquardt
Today/Tonight and Aviation/Marine...Davis
Saturday THROUGH Thursday...Collar



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