Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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370
FXUS63 KMKX 251501 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1001 AM CDT SAT JUN 25 2016

.UPDATE...

There could be a couple showers or storms in the west this
afternoon on the leading edge of deeper moisture surge. Latest
HRRR and NAMNest keep it dry into the evening though, so not a lot
of confidence with the afternoon precip chances. Still looks like
bulk of showers/storms will hold off until after midnight.

No updates expected to the temps for the afternoon, as most places
away from Lake Michigan are still expected to approach or reach 90
degrees.

&&

.AVIATION/18Z TAFS/...

VFR conditions will persist for much of the time through Sunday.
Showers and storms will mainly hold off until after midnight
tonight. Could see some lower visibilities at times with
moderate/heavy rainfall. Soundings and MOS also show a brief
period of lower ceilings possible as the trough moves through
tomorrow morning. VFR conditions are then likely for the afternoon
hours.

&&

.MARINE...

South winds should become more southeast, and could approach small
craft advisory conditions this afternoon, with a few gusts in the
lower 20kt range. Thunderstorms are likely tonight with the passage
of a weak cold front. Winds will turn west on Sunday and remain
below small craft advisory levels.

&&

.PREV DISCUSSION... /Issued 317 AM CDT SAT JUN 25 2016/

TODAY AND TONIGHT...Forecast Confidence Is High.

High pressure is sliding east as a trough of low pressure/cold
front approach from the northwest. 925 mb temps climb into the
mid 20s this afternoon, and should translate into highs pushing
near 90 in a few spots. The lake counties will see a bit of
onshore flow, so a tad cooler there, especially up toward
Sheboygan. Dew points will definitely be on the rise, so look for
very muggy conditions by afternoon.

There is some warm advection and lift this afternoon, but the cap
looks formidable and should hold, especially from Madison on east.
There is a better chance that we could see some early convection
with with the WAA this afternoon west of Madison, so will move up
the chances slightly there. Some of the high res models are very
bullish with some convection across the CWA this afternoon, but
this looks to be a symptom of exaggerated dew points more than
anything.

For tonight, the front will be pushing in later in the evening.
Convection likely will lose some steam as it pushes in, as the
better jet and forcing remain north of the area. SPC has the area
in a marginal risk, with the slight risk just northwest of the
CWA. Can`t argue with that. A warm and muggy night for sure.

SUNDAY THROUGH MONDAY NIGHT...Forecast Confidence Is Medium.

Models take the cold front eastward through the area on Sunday,
exiting by later in the afternoon. Low level frontogenesis is
stronger on the NAM than the GFS. Elongated 500 mb vorticity
maximum pushes through as well in the morning, exiting in the
afternoon.

Adjusted area forecast soundings indicate some weakening tall
skinny mean layer CAPE in the morning, then stabilizing by middle
to late afternoon. Best shot at lingering showers and storms would
be in the morning, then decreasing in the afternoon. Continued
this trend with POPs for Sunday.

Kept the warm temperatures for Sunday as well, despite some
expected cloud cover with any lingering showers and storms. 925 mb
temperature fields from models support upper 80s in most of the
area. These values may be several degrees too warm, if the clouds
are more widespread than forecast.

Models show another cold front sliding southeast through the area
Monday morning, with a decent shot of cold air advection behind
it into Monday night. A 500 mb shortwave trough with several
embedded vorticity maxima push southeast through the area as well.

Adjusted area forecast soundings are rather dry during this time,
and may just see some cumulus clouds develop Monday and linger
into Monday night. Kept dry forecast going for now. Temperatures
should drop to more seasonable values Monday into Monday night,
with lower dew points bringing less humid conditions.

TUESDAY THROUGH FRIDAY...Forecast Confidence Is Medium.

ECMWF/GFS models generally show high pressure sliding southward
from Minnesota into Iowa Tuesday into Wednesday. The ECMWF is
slower than the GFS and brings a 500 mb shortwave trough through
the area Tuesday, bringing light QPF to the area. The quicker GFS
is dry Tuesday. They then show dry conditions into Wednesday. For
now, used consensus blend of POPs and kept the dry forecast going
for Tuesday into Wednesday. Temperatures should be a little below
seasonal normals, with onshore winds bringing cooler highs near
the lake each day.

The GFS is quicker than the ECMWF with the next cold frontal
passage later in the week. The GFS brings it through the area
Thursday, with the ECMWF Thursday night. Not much in the way of
500 mb support with the front. More differences develop on Friday,
as the front stalls or moves back north as a warm front. Kept
consensus blend of POPs for Wednesday night into Friday for now.
Temperatures should be around seasonal normals.

AVIATION/12Z TAFS/...

VFR conditions should prevail through the TAF period. A trough of
low pressure will move across the area tonight, likely bringing a
round of showers and thunderstorms. The activity should reach KMSN
around 04-05z Sunday and KMKE/KUES/KENW after about 08-09z. The
showers and storms will be weakening by the time they reach the
southeast. There could be brief MVFR conditions with any heavier
showers/storms. Winds will be southerly today, shifting to
westerly in the wake of the front late tonight and early Sunday
morning.

MARINE...

Southerly winds could approach small craft advisory conditions
this afternoon, with a few gusts in the lower 20kt range.
Thunderstorms are likely tonight with the passage of a trough of
low pressure. Winds will turn westerly on Sunday, and remain
below small craft advisory levels.

&&

.MKX Watches/Warnings/Advisories...
WI...None.
LM...None.
&&

$$

UPDATE...DDV/Hentz
TODAY/TONIGHT AND AVIATION/MARINE...Davis
Sunday THROUGH Friday...Wood



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