Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 251736 AAB
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1236 PM CDT Wed Apr 25 2018

.UPDATE...

The forecast remains on track for the afternoon.

&&

.AVIATION(18Z TAFS)...

VFR conditions will continue through Thursday. Skies will remain
mostly clear into Thursday, with mid/high level clouds increasing
from the west in the afternoon as a cold front approaches. A few
showers are then possible mainly Thursday evening and early night
as the cold front moves through.

Will have to watch winds near Lake Michigan tomorrow. Prevailing
winds may be strong enough to keep the lake breeze offshore into
early afternoon, but it seems the lake breeze will eventually win
out near the lake.

&&

.PREV DISCUSSION... (Issued 910 AM CDT Wed Apr 25 2018)

UPDATE...

Mostly sunny skies are expected today. The forecast looks on track
for the remainder of the day, though might have to bump temps down
a couple degrees near Lake Michigan.

MARINE...

Gusty north winds this morning will gradually ease through the
day, with slowly subsiding waves as well. The Small Craft Advisory
end times still look reasonable.

Winds and waves could reach advisory levels again Thursday night
into early Friday.

PREV DISCUSSION... (Issued 556 AM CDT Wed Apr 25 2018)

UPDATE...No changes at this time.

AVIATION(12Z TAFS)...Bulk of clouds have cleared southern WI. Few
cumulus will redevelop this morning. VFR conditions expected this
period as drier air and subsidence settle into southern WI. Gusty
winds will continue near the lake and will redevelop most inland
areas.

PREV DISCUSSION... (Issued 307 AM CDT Wed Apr 25 2018)

SHORT TERM...

TODAY AND TONIGHT - Confidence...High.

Synoptic scale lift associated with mid-level short wave racing off
to the east early this morning.  Increasing subsidence and return of
low to mid level dry air putting kibosh on overnight clouds, per
latest satellite imagery.  Hence expect mostly sunny conditions for
today, with mostly clear skies tonight.  Few-sct cumulus will likely
redevelop for a time. Subsidence associated with short wave ridging
remains in place during the period.  May see some few-sct high
clouds tonight ahead of approaching northern Plains short wave.
Cooler 925H temps and north to northeast surface winds will result
in a cooler day, with high temperatures from the mid 50s to mid 60s
away from the lake.  Light winds and mostly clear skies will allow
temperatures to fall into the low to mid 30s tonight.

LONG TERM...

Thursday through Friday... Forecast confidence is Medium.

We will get back into weak southerly flow ahead of an
upper/surface trough Thursday. We`ll head into the mid 60s for
highs. Southern WI will be in a dry, mixed environment that is
conducive for lower dewpoints and relative humidity. We lowered
dewpoints into the lower 30s, but this type of pattern may feature
even lower values.

There is a small chance for showers right behind a cold front Thu
evening, with better chances north of I-94. This is within an
small area of deeper saturation and forcing. A brief period of
gusty north winds are expected as well.

Another mid level shortwave trough will barrel through the Upper
Great Lakes Friday afternoon. Timing of this wave is a little
uncertain between the models, but scattered to numerous rain
showers are expected with this potent system. Steep low level
lapse rates could lead to a few rumbles of thunder as well. Areas
east of Green Lake and Madison have the better chance for precip.

Saturday through Monday... Forecast confidence is High.

The upper trough will hang around the Great Lakes through
Saturday, so expect a few diurnal cumulus clouds around. More
sunshine inland and no lake influence will allow temps to get into
the upper 50s. High pressure and increasing southerly flow for the
first half of next week will usher much warmer air into southern
Wisconsin. Sunday and Monday will be dry, with Monday being the
warmest of the two with highs in the mid 70s.

Tuesday and Beyond... Forecast confidence is Medium.

An approaching low pressure system from the Northern Plains will
bring showers and thunderstorms to the Upper Midwest. Depending on
the speed of this next system, Tuesday may remain dry and very
warm with highs in the mid 70s, but dewpoints will be on the rise.
The 00z ECMWF shows a more prominent northern upper low and
therefore a faster track than the GFS, which focuses more on a
closed off upper trough over the southwest and gives us a
prolonged period of rainy weather. We will be able to get a better
idea of severe thunderstorm chances in a few days.

AVIATION(09Z TAFS)...Patchy low VFR and MVFR clouds will
continue to erode early this morning as subsidence and drier air
surges into southern WI. Gusty winds by the lakeshore will
diminish but remain gusty through the morning. VFR conditions are
expected for today and tonight. Some few-sct cumulus wl likely
develop later this morning but dissipate for tonight.

MARINE...Strongest northeast winds are expected this morning
due to lingering pressure gradient and weakening low level cold air
advection.  Gusts will diminish late this morning and afternoon, but
lingering onshore flow will result in slower fall in wave heights.
For now, will continue ongoing Small Craft Advisory with northern
zone expiring in the early afternoon and rest of the area expiring
in the evening.  Later shifts may need to fine tune ending time
as waves slowly subside.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory until 7 PM CDT this evening for LMZ644>646.

     Small Craft Advisory until 1 PM CDT this afternoon for LMZ643.

&&

$$

Update...DDV
Today/Tonight and Aviation/Marine...MBK
Thursday THROUGH Tuesday...Cronce


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