Sun Prairie, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

142
FXUS63 KMKX 212101
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
301 PM CST Fri Feb 21 2025

.KEY MESSAGES...

- Quiet weather prevails into the weekend and temps will warm
  up with highs in the 30s and 40s into early half of next week.

- Ice jams will be possible on area rivers along with thinning
  ice on area lakes with the warmer temps, thus use caution if
  venturing around any frozen bodies of water through early next
  week.

- Precip chances return early next week with low end chances
  (<30%) Sunday evening-Monday morning and chances (<30%) again
  Monday night- Tuesday. Mainly expecting rain and/or wintry mix
  with the warmer temps.

- Wednesday looks to have the highest potential (40-60% chance)
  for more widespread precip, but uncertainty remains in the
  low pressure track and precip type.

&&

.SHORT TERM...
Issued 259 PM CST Fri Feb 21 2025

Tonight through Saturday night:

Influence from the the surface high pressure continues to
lessen through tonight as the center of it slides south and east
up the Ohio River Valley overnight. Southwesterly winds have
been established over the area and will continue overnight.
Should see a bit warmer temps tonight with southwesterly flow
and some high clouds working their way into the area. However,
given the snow pack, still looking at overnight lows dipping
into the single digits for inland southern WI while areas closer
to Lake Michigan linger into the teens.

Given the the low-level WAA, Saturday will see temps a few
degrees warmer than today rising into the upper 20s and even low
30s. While models have struggled with the WAA patterns lately,
thinking the snow pack is enough to limit temps from
overachieving closer toward the 90th percentiles. Also looking
at southwesterly winds to pick up for Saturday afternoon as the
pressure gradient across southern WI tightens being between the
departing high and a low pressure trekking across the Hudson Bay
region. Only looking at gusts up to around 20-25 mph.
Otherwise, nightly low temps gradually warm again with this WAA
pattern and looking at lows in the teens to 20s along the
lakeshore. Wagner

&&

.LONG TERM...
Issued 259 PM CST Fri Feb 21 2025

Sunday through Friday:

Overall, southern WI looks to be established under persisting
northwesterly upper-level flow Sunday through the first half of
the week. Models prog a series of mid-level shortwave troughs to
work their way down across the area with this pattern. Thus
giving southern WI two rounds of low end precip chances (<30%)
Sunday night- Monday and again Monday night-Tuesday. Given the
low-level WAA pattern ahead the main midweek system with temps
around or greater than freezing paired with diminishing snow
pack expecting these rounds to either fall as rain or a wintry
mix, especially for the cooler overnight hours.

Then Wednesday looks to be the better chances to see widespread
precip across southern WI as a broader upper-level trough digs
across the Midwest. This will bring a surface low/ cold front
across the region along with the precip chances. However, there
remains uncertainty in the lows track, strength, and type thus
leaving uncertainty in exact amounts and precip type with the
midweek system. Nevertheless, still a consistent signal for
40-60% PoPs at this time.

Otherwise, the main focus on the extended period will be the
near to above normal (+5F to 10F) temps for this time of year.
Looking at daily highs Sunday through midweek in the upper 30s
to mid 40s. Would not be surprised to see temps creep toward the
90th percentile range of the NBM in the upper 40s and maybe
even crack 50F, especially for Monday and Tuesday if the snow
packs disappears by then. While the warm up will be appreciated
after the recent cold stretch, it may lead to a few hydro
impacts such as ice jams on thawing rivers as well as thinning
ice on area lakes. Thus use caution if venturing out/around any
frozen bodies of water with the warm up. Lastly cannot rule out
snowmelt refreezing during the overnight hours when temps dip to
around or below freezing, especially on untreated surfaces.

Wagner

&&

.AVIATION...
Issued 259 PM CST Fri Feb 21 2025

VFR conditions prevail through the period with high pressure
working its way south and eastward up the Ohio River Valley.
Lighter southwesterly winds have established themselves across
southern WI on the backside of the departing high. Will see
southwesterly winds pick up to around 20kt by Saturday afternoon
as southern WI is sandwiched between the departing high and a
low pressure system working its way across the Hudson Bay
region. Otherwise, just looking at higher level, thin layer of
clouds (>150kft) to build into the region overnight into
Saturday.Wagner

&&

.MARINE...
Issued 259 PM CST Fri Feb 21 2025

High pressure continue to move east-southeast up the Ohio River
Valley through the evening and has brought southwesterly winds
to Lake Michigan. As the high pressure moves into the Mid-
Atlantic region into Saturday, a low pressure works its way
across the Hudson Bay region. With Lake Michigan in between the
two systems, expect increasing southwesterly winds to develop
overnight into Saturday with gusts, especially across northern
portions of the Lake to approach 30 kt, but likely remain below
gale force. Nearshore waters may approach small craft conditions
as well, but the offshore flow may keep these conditions more
offshore. Will also have a window for moderate freezing spray
overnight with the increasing winds and waves paired with
another bitter cold night. Will see southwesterly winds and
gradually warmer temps Sunday into early next week. There will
be a few weak low pressure to work their way across the region
Sunday night-Monday and another one Monday night-Tuesday. These
weak lows only look to bring some scattered precip and briefly
turn winds west-northwesterly before returning southwesterly.
Then a larger low pressure is progged to track across the Upper
Midwest Wednesday, which will drag a cold front across the lake
and turn winds more north-northwesterly by the second half of
the week.

Wagner

&&

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

$$

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