Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 180239 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
839 PM CST Fri Feb 17 2017

.UPDATE...

A few high clouds should move north to northeast through the area
over the next several hours. Otherwise, expect mostly clear skies
overnight into Saturday morning, with the dry airmass in place.
Lows will only drop into the middle to upper 30s, which are
higher than the normal highs for this time of year.

A weak cold front slides southeast through the area around sunrise
Saturday morning, with weak cold air advection behind it into
Saturday. This may keep highs just below record highs of 57
degrees at Milwaukee and Madison. It will be close. Still a very
warm day for this time of year.

&&

.AVIATION/06Z TAFS/...

Main issue will be low level wind shear into the overnight hours.
A low level jet stream, with southwest winds up to 45 knots, are
expected at 2000 feet until around 10Z Saturday. Given the light
southwest winds overnight, will keep low level wind shear mention
in TAFs and across the area. Light west winds are expected
Saturday into Saturday night.

VFR conditions are expected overnight into Saturday night across
the area. A weak cold front will slide southeast through the area
around sunrise on Saturday, with high pressure moving through
later in the day and into Saturday night.

A few high clouds may move through the area overnight. Otherwise,
mostly clear skies are expected into Saturday morning. Some high
clouds may move into the area from the northwest Saturday
afternoon and night.

&&

.MARINE...

Winds and waves are expected to remain below Small Craft Advisory
levels through this weekend. Southwest winds may gust to around 20
knots overnight, before a weak cold front moves through around
sunrise Saturday morning. High pressure moves into the area
Saturday afternoon and lingers Saturday night.

Winds and waves may reach Small Craft Advisory levels Monday into
Monday night, as a tight pressure gradient develops with the next
low pressure system moving through the region.

&&

.CLIMATE...

Record high of 64 degrees was observed at Milwaukee today, Friday
February 17, 2017. This smashed the previous record of 55 degrees,
set in 1981. Madison reached 60 degrees, which was just below its
record high of 61 degrees, also set in 1981.

Record highs will be possible at these sites each day over the
weekend into early next week, as the unseasonably warm airmass
lingers over the region. Milwaukee may have a tougher time
reaching record highs Sunday and Monday, with onshore winds
developing.

&&

.PREV DISCUSSION... /Issued 237 PM CST Fri Feb 17 2017/

TONIGHT AND SATURDAY - Confidence...Medium to High

Mid level energy rides well to our north tonight. In the low levels
a surface front will cross the area with a shift in winds to the
northwest. The 100/500 millibar thicknesses collapse the pronounced
thermal ridge in place. Warmest airmass is proggd to shift a bit
south on Saturday however the degree of cooling on the GFS looks
overdone and would prefer to lean bit more towards the ECMWF/NAM
thermal pattern. MOS temps suggest we are back into the 50s though
if we can mix deeper than what the GFS/NAM Bufkit soundings imply
then some areas could make a run towards 60 again.

SATURDAY NIGHT AND SUNDAY...Forecast Confidence...High

High pressure will bring continued mostly clear skies and above
normal temps Saturday night and Sunday. High temps will likely
approach record levels once again Sunday, except for near Lake
Michigan. Looks like onshore winds will arrive fairly early in
the day, keeping it cooler near the lake.

MONDAY AND TUESDAY...Forecast Confidence...Medium

A trough of low pressure will swing through the region early next
week. Temperature and moisture advection ahead of the trough will
result in rain developing on Monday, persisting through Monday
night or early Tuesday as the trough moves through. There are some
timing differences among models, which leaves some uncertainty
with exact precip timing and high temps. The slower ECMWF/Canadian
solutions would hold rain off until later in the day Monday and
also give move time for milder temps pushing 60 away from Lake
Michigan. The faster GFS/NAM are cooler, though still look like
at least low 50s away from the lake.

With no significant colder airmass behind the departing trough,
should see highs remain well above normal on Tuesday.

WEDNESDAY THROUGH FRIDAY...Forecast Confidence...Medium

Southern Wisconsin should be situated between high pressure to the
south and a passing low to the north on Wednesday. The GFS is
suggesting a little forcing at the base of the trough may bring
some rain, though the ECMWF and Canadian solutions remain dry. Did
throw some pops in there per the GFS, but confidence is fairly
low with this precip potential. Otherwise, will be yet another
mild day. ECMWF and GFS 925 mb temps give potential for record
highs given enough sunshine and mixing.

Strong low pressure will approach the area on Thursday, moving
through Thursday night or Friday, depending on model timing.
Models have been consistent showing a strong low in the region,
but have hopped around with the track the last 24-48 hours. Thus not
putting a lot of stock in the current solutions given the
variability. That said, 12Z model runs today do show better
agreement in taking the low to the northwest of the forecast area.
If this were to pan out, above normal temps and mainly rain would
be expected Thursday and Friday. Thunder would also be possible
if this track were to verify given the strength of the low and the
instability in the models. Plenty of time for the details to
change given this system is about a week out.

AVIATION/00Z TAFS/...Still looking like only concern over the
next 24 hours or so will be potential for LLWS tonight. Progs
still show a wsw LLJ arriving which given decoupling this evening
will set up the shear scenario. All in all soundings are bone dry
with mid level ridging dominating.

MARINE...Winds and waves are expected to remain below small craft
advisory levels through the weekend.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

UPDATE...Wood
TONIGHT/Saturday AND AVIATION/MARINE...Collar
Saturday NIGHT THROUGH Friday...DDV



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