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248
FXUS63 KMKX 150846
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
346 AM CDT Wed May 15 2024

.KEY MESSAGES...

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- Next round of showers and storms expected for Thu and Thu
  evening. Otherwise a warming trend into the weekend with just
  small chances of rain.
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&&

.SHORT TERM...
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Issued 346 AM CDT Wed May 15 2024

Today through Friday night:

Scattered stratus over far srn WI will dissipate later this
morning as low pressure weakens as it moves ewd across the Ohio
Valley, and nly winds bring drier air into the region.
Otherwise the sfc ridge will remain over WI today before
shifting ewd tnt. Temps will return to the upper 60s to lower
70s well inland with near 60 at the lake front.

A weak sfc low and upper level trough will move from MN to wrn
Lake Superior on Thu. PWs will increase to 1-1.2 inches with
very marginal instability, but increasingly moist soundings. The
HREF and GFS/ECMWF support likely PoPs from west to east
through the day as the trough passage extends south into the
area. Scattered showers to then linger into Thu nt with the
weakening sfc trough passage over the area and another weak
shortwave trough approaching from the west. The trough will pass
early Fri AM but isold showers could linger in far ern or srn
WI. Some uncertainty on timing of drying for Fri which will
impact cloud cover and temps. At this time counting on some
sunshine with temps ranging from the 60s near the lake to middle
to upper 70s over south central WI. Shortwave ridging and a dry
fcst for Fri nt.

Gehring
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&&

.LONG TERM...
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Issued 346 AM CDT Wed May 15 2024

Saturday through Tuesday:

Ridging nudging northward into the Upper Mississippi Valley and
steady southerly winds at the surface may lead to widespread
temperatures over 80 degrees on Saturday. Modeling has come into
agreement that the interplay between an Ohio Valley low and a
500 mb shortwave driven low in Canada and the northern Plains will
drape a cold frontal feature through Wisconsin Saturday evening,
although better forcing remains across northern Wisconsin and the
UP of Michigan as upper level ridging steers the northern low into
northern Canada. In addition, this upper level ridging brings in
warmer air aloft and prevents instability development during the
day. Therefore, kept the NBM 15 to 30 percent PoPs for this
timeframe.

High pressure remains prominent through Saturday night into
Sunday, with an additional shortwave propagating eastward from the
Colorado Rockies Sunday night into Monday and a developing low in
the lee of the Canadian Rockies creating a baroclinic zone in the
Upper Midwest. Plenty of uncertainty remains in exact timing and
intensity of precipitation across southern Wisconsin from Sunday
onward as triggers for convection transition to a shortwave-driven
pattern beneath general ridging. Because of uncertainty, left NBM
PoPs alone. However, there will likely be periods of dry
conditions Sunday into Monday.

Intrusion from the tropical jet stream into the central Plains
midweek may result in enhanced cyclogenesis and therefore better
chances for widespread precipitation Tuesday into Wednesday.

Gehring
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&&

.AVIATION...
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Issued 346 AM CDT Wed May 15 2024

Isold MVFR Cigs over far srn WI will dissipate by late morning
as drier air arrives. Otherwise VFR conditions today into Thu
AM.

Gehring
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&&

.MARINE...
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Issued 346 AM CDT Wed May 15 2024

Low pressure around 29.6 inches will move across the Ohio Valley
today, while the surface ridge of 29.9 inches over WI moves
across Lake Michigan tonight. Modest northerly winds over the lake
today will become light and variable tonight.

Light to modest east to southeast winds will then develop for
Thursday and Thursday evening as weakening low pressure around
29.6 inches tracks from northern Minnesota into western Lake
Superior. Light and variable winds are then expected Friday and
Friday night as weak high pressure develops over the lake late on
Friday.

Gehring
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&&

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

$$

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