Air Resources Laboratory banner image
Air Resources Laboratory web site National Oceanic and Atmospheric Administration (NOAA)

wi discuss

Office: MKX

FXUS63 KMKX 170207

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
907 PM CDT Tue Aug 16 2022

(Issued 900 PM CDT Tue Aug 16 2022)

Influence from an area of high pressure meandering around the
Great Lakes continue to bring relative benign weather to southern
WI tonight through midweek. Given the light winds, we are still
keeping an eye for some patchy fog development overnight mainly
for areas west of I-90/39 where dewpoints are a bit warmer and
dewpoint depression are lower. However with subsidence from the
broad high, dewpoints are already lower further east, closer to
the lake. Latest obs show values dipping into the low 50s and even
the upper 40s in some spots, thus fog development is not likely
closer to the lake. Additionally we are expecting this drier air
to gradually advect westward overnight across the CWA. Given
these trends, chances for fog development will lower than
previous nights and if any develops, will likely be patchy in
nature. Otherwise, the current forecast remains on track.



(Issued 300 PM CDT Tue Aug 16 2022)

Tonight through Wednesday night:

With clearing skies and light winds again tonight, expect another
cool night with the potential for fog in low-lying areas and
areas in/around river valleys and irrigated fields. Not expecting
dense fog at this time, but this will be something to keep an eye
on overnight.

Wednesday we will see high pressure continue to work its way
southeast across the area, keeping winds light and temperatures a
degree or two warmer than today. This will favor another day with
some passing high clouds and afternoon cumulus. A few high-res
models do show some shower activity developing along the lake
breeze boundary Wednesday afternoon. There is quite a bit of dry
mid-level air moving into the area during the afternoon, so if we
can get anything shower activity to develop expect the coverage
to remain isolated. While there may be a small amount of SBCAPE
that develops during the afternoon hours, the overall lack of
shear should limit the ability to maintain a sustained updraft,
so left mentions of thunder out of the forecast for Wednesday

Wednesday night will be another seasonable cool night with light
and variable winds, and likely another potential for some fog in
areas described above.



(Issued 300 PM CDT Tue Aug 16 2022)

Thursday through Tuesday:

The main concern for the extended is low pressure that will be
dropping into MN/IA from ND late this week and sticking around the
region through the weekend, before moving east across southern WI
late this weekend. Thursday looks to be mostly dry, although
south-central Wisconsin may see some showers and storms overnight
and into Friday morning. Better shower and storm chances arrive
Friday through Sunday becoming more widespread in the afternoon
hours as diurnal heating helps to destabilize the atmosphere. By
Monday afternoon we may see some lingering activity, but will
likely become more isolated. Overall, the timing of showers and
storms remains difficult to nail down for this weekend as it is
largely dependent on the movement and speed of the low.

High temperatures on Thursday and Friday will be in the upper 70's
to low 80's as warm air is ushered ahead of the approaching low
pressure system. Temperatures on Saturday and Sunday will be
highly dependent on how showers and storms play out. Currently,
have temperatures warming into the mid to upper 70s. However, it
is possible temperatures could end up cooler than currently



(Issued 905 PM CDT Tue Aug 16 2022)

With high pressure lingering over the region, VFR conditions will
prevail through the period with lighter north to northeasterly
winds. Could still see some patchy fog develop overnight across
inland location, but with drier air moving westward across
southern WI, chances will be lower than previous nights. MSN and
JVL terminals will have the best chance at seeing some patchy fog
develop overnight through early Wednesday morning, but confidence
remains on the lower side. Otherwise, expect another round of
diurnal clouds to develop around/after 18Z on Wednesday, with
cloud bases around 4-6kft. Additionally eastern terminals will
likely experience a easterly wind shift Wednesday afternoon as a
lake breeze develops and pushes inland. Also cannot rule an
isolated shower or two to develop ahead of the lake breeze, but
chances and coverage if anything does develop will be minimal.



(Issued 300 PM CDT Tue Aug 16 2022)

As high pressure moves closer to the area northeast winds will
relax over Lake Michigan tonight to around or less than 10 kt.
Expect these light winds to continue on Wednesday, with lake
breeze boundaries developing on either side of the lake during the
afternoon hours. Thursday and Friday, as high pressure sinks
southeast of the area and we start to see south-southwest winds
develop ahead of a slow moving system moving in from the west.
Winds still look to remain below 20 kt for the most part on
Thursday and Friday, with the strongest winds expected across the
northern half of Lake Michigan.

For the upcoming weekend, a slow moving low pressure system is
progged to move over southern Lake Michigan, bringing periods of
showers and thunderstorms. While this surface low will not be
wound up enough to bring significant winds to Lake Michigan, wind
directions will generally start off from the southeast, becoming
east-northeast this weekend as the low moves over the south half.
Then by early next week, winds should slowly take on a more
northerly component.





Visit us at

Follow us on Facebook, Twitter, and YouTube at:

Office: ARX FXUS63 KARX 170320 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 1020 PM CDT Tue Aug 16 2022 .DISCUSSION...(This evening through Tuesday) Issued at 249 PM CDT Tue Aug 16 2022 Key Messages: - River valley fog Wednesday morning - Precipitation chances Wednesday through Sunday - Seasonable...then cooler end to the week After a foggy start, we enjoyed partly cloudy skies and light winds with temperatures in the 70s to around 80 for much of the early afternoon. Water vapor satellite imagery, 500mb heights, and lightning at 2pm had a mid-tropospheric ridge over the western U.s., a broad trough over the eastern U.S. Locally, we are under northwest flow aloft with a shortwave trough over parts of Manitoba/Ontario. This shortwave was resulting in a cluster of showers and thunderstorms across northern MN. With the heating and reaching convective temperatures, cumulus have developed. Valley fog should re-develop tonight. The cumulus should decrease again tonight with the loss of heating and a low level inversion setting up. Winds remain light through about 2.5km. We have some high clouds moving in overnight, however, these look to reach some of the western and northern area, and may mitigate some of the fog, but should allow the Wisconsin River valley areas to fog in with patchy fog elsewhere. A series of shortwave troughs will move into this northwest flow and affect the area into the weekend. This first wave should send showers and thunderstorms toward the area, however should mostly weaken. Moisture transport increases for northwest areas Wednesday night, but especially Thursday afternoon. This is occurring as a stronger shortwave drops southward into the Dakotas/MN. We remain under the influence of the area of low pressure as it closes off and tracks south through the Mississippi Valley through Sunday. The EC ensemble mean at LSE/RST...related to the total rainfall through the weekend is around 0.9-1.0 inch...with a range of 0.2 to 2.4 inches. The GEFs ensemble mean is 0.6 with a range of 0.1 to 1.8 inches. Temperatures will again be seasonable Wednesday with highs in the 70s to lower 80s. Generally seasonable or cooler than normal with the cloudcover and chance for precipitation through the weekend. Highs should be held to the 70s. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1020 PM CDT Tue Aug 16 2022 CIGS: on the whole, SCT-BKN VFR conditions expected through the period - mostly of the mid/high variety. KLSE could/should see a few hours of LIFR cigs Wed morning, centered around 12z, associated with river valley fog. WX/vsby: river valley fog at KLSE the main impact. Setup looking quite good for a few hours of 1/4SM with deep light wind layer and T/Td spread at 03z of 7F also suggestive of dense fog. However, sfc winds light and vrb...light southeast preferred while north winds tend to inhibit 1/4sm. Overall, will hold with a few hours of 1/4SM, may not be a long as previous thought and some adjustments in timing in/out may be necessary toward 12z. Winds: light wind field through the period as weak high pressure meanders slowly southeast. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ DISCUSSION...Zapotocny AVIATION.....Rieck
Office: GRB FXUS63 KGRB 170339 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1039 PM CDT Tue Aug 16 2022 Updated aviation portion for 06Z TAF issuance .SYNOPSIS... Issued at 406 PM CDT Tue Aug 16 2022 Seasonable temperatures for the rest of the work week. The chance for showers will gradually increase during the latter part of the work week, then scattered showers and some thunderstorms are expected for the weekend. Amplification of the western ridge/eastern trough pattern is expected the next few days as a series of shortwaves dig south from Canada. The shortwave energy will eventually close off over the Upper Midwest/Great Lakes region, temporarily pulling the eastern trough axis back to the west for the weekend. The trough should shift back east next week. Rain chances will slowly increase from northwest to southeast across the area during the latter part of the work week, then scattered showers and thunderstorms are expected for the weekend. Seven-day rainfall totals will probably range from near to a little below normal in the eastern part of the area to above normal in the west. Temperatures throughout the period probably won't stray too far from seasonal normals, running a little warmer on days with more sunshine and a little cooler on days with more clouds and precipitation. && .SHORT TERM...Tonight and Wednesday Issued at 406 PM CDT Tue Aug 16 2022 Quiet weather will continue tonight as weak high pressure continues to ridge into the area from Ontario. As stronger shortwaves begin digging farther west toward the Northern Plains tomorrow, the forecast area will temporarily become situated in a col in the mid-level wind field between the energy to the west and the main portion of the eastern NOAM longwave trough to the east. This suggested slowing the arrival of rain chances a bit on Wednesday. Trended the forecast in that direction, but some further adjustment may still be necessary with subsequent issuances. Edged temps across most of the above the NBM guidance for tomorrow given current temps across the area and a bit of anticipated warming at 850 mb. The exception will be the NW part of the area which will have more clouds. .LONG TERM...Wednesday Night Through Tuesday Issued at 406 PM CDT Tue Aug 16 2022 The main focus from this forecast period revolves around precipitation trends associated with a closed low. Temperatures will be dependent on when and where the rain falls and cloud cover. Wednesday night through Thursday...A weak mid-level shortwave over Ontario will become nearly stationary during this time period. Meanwhile, low to mid-level moisture associated with this shortwave will extend into northwest WI. A few showers and thunderstorms may reach north-central WI Wednesday night as a result. However, heading into Thursday, a secondary (stronger) shortwave will dig over eastern ND/northern MN. The two shortwaves will slowly combine on Thursday over the Upper Mississippi Valley and bring shower and thunderstorm chances to the forecast area, with the best chances over central and north-central WI. Rest of the extended...The shortwave will continue to strengthen over MN and eventually become closed sometime Thursday night into Friday. Models are in agreement with the low's track dropping south over MN on Friday, which will cause a mean south/southwest flow over the forecast area. As the moisture continues to circulate around the closed low, additional showers and isolated storms will remain possible across the forecast area on Friday. Due to the slow east/southeast progression of the closed low from southern MN to southern WI, periods of showers and isolated thunderstorms will also be possible throughout the remainder of the weekend and into early next week. However, models do not suggest a complete wash-out for the forecast area. && .AVIATION...for 06Z TAF Issuance Issued at 1030 PM CDT Tue Aug 16 2022 Generally good aviation weather conditions are expected throughout the TAF period. Patchy fog is possible overnight, mainly across east-central Wisconsin and CWA. The fog is not expected to be as widespread or persistent; therefore, will only include as a TEMPO group. A frontal boundary will bring some mid clouds Wednesday afternoon as it approaches northwestern Wisconsin and possibly some showers to north-central Wisconsin Wednesday evening. At this point will only include a VCSH at KRHI as confidence in hitting this TAF site is still fairly low with this issuance. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS.......Skowronski SHORT TERM.....Skowronski LONG TERM......Hykin AVIATION.......Kurimski