163
FXUS63 KDLH 191717
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1217 PM CDT Fri Jul 19 2024

.KEY MESSAGES...

- Mainly quiet weather today with highs in the low 80s. A 20%
  chance for showers/storms in north-central Minnesota this
  afternoon and evening.

- Periodic chances for showers and storms will persist through
  Tuesday with highs generally in the upper 70s to low 80s.

&&

.DISCUSSION...
Issued at 408 AM CDT Fri Jul 19 2024

Some mostly clear to partly cloudy skies out there this morning
along with some patchy fog, which will lift just after sunrise.
Sunshine is expected to be prevalent through today with warmer
highs in the low 80s for most places. As early as this
afternoon, we may see a few showers and possibly a storm or two
pop up (15-25% chance). This will be due to an upper level
trough moving through along with southwesterly warm air
advection aloft. The current air mass is rather dry, but it will
saturate more this afternoon with PWATs approaching 1" to 1.5".
A nose of warm air aloft may cap surface-based instability for
most places. Therefore, rain chances have somewhat decreased for
this afternoon and will be limited mainly to north-central
Minnesota. If a storm or two do pop up, they are not expected to
be severe with limited shear aloft, but they could produce some
brief heavy rain.

Going into tonight, we watch for the arrival of a backdoor cold
front from Ontario. This will keep the shower/storm chances
(~20%) around the Borderland.

This backdoor cold front will continue south into central
Minnesota / northwest Wisconsin by Saturday afternoon, and this
will serve as a lifting mechanism for convection coupled with
diurnal heating. As such, we can expect an increase in
shower/storm activity Saturday afternoon (50-65% chance). PWATs
around 1.25" will likely be more realized on Saturday with
better forcing from the cold front, and as such, there will be
better chances to squeeze out a few tenths of an inch of rain
for many areas from afternoon showers and storms. Similar to
Friday, weak shear will keep these storms pretty vertically
stacked, so strong storms are unlikely. But, they will certainly
be capable of producing heavy rain and perhaps some gusty
winds. While most places can expect up to a few tenths of an
inch of rain, some localized amounts approaching three quarters
of an inch or so can`t be ruled out. The showers and storms will
gradually diminish in the evening. Otherwise, between the
storms, sunshine is expected with warm high temperatures in the
low 80s. While confidence is not high at this time, the HRRR
does suggest that there could be a bit of elevated haze due to
wildfire smoke in Canada that could pass through the region
Saturday into Saturday evening.

Similar weather is expected on Sunday, except that rain chances
will be displaced further south as the cold front progresses
south. Parts of east-central Minnesota into northwest Wisconsin
may see a 20-30% chance for showers/storms while areas north
remain dry.

A wavy pattern aloft on Monday will keep some small chances for
diurnal showers/storms around, but again, strong storms are not
expected. Tuesday may bring perhaps some slightly more
organized shower/storm activity as another upper level trough
swings through, this time with some more shear aloft (0-6 km
shear around 30 kt) and some more appreciable SBCAPE around or
perhaps above 1000 J/kg for some areas. Some stronger storms may
be possible, but it`s too early to be confident about any
details beyond that.

A cold front may pass through Tuesday going into Wednesday, and
this may bring an end to most rain chances on Wednesday and
relatively cooler highs back into the 70s on both days.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1217 PM CDT Fri Jul 19 2024

VFR conditions this afternoon with diurnal cumulus populating over
the region. There is a chance for some light showers and sprinkles
to accompany the cumulus but overall not expecting much. High res
guidance has also greatly backed off the coverage of activity.
Overnight, could still see some fog formation (40-60%). If fog does
manage to form it will quickly leave between 12-14Z. A cold front is
expected to be dropping south Saturday morning out of Ontario and
could bring some morning showers and storms across northern MN. This
boundary will continue south through the afternoon spreading the
chances for showers and storms.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 408 AM CDT Fri Jul 19 2024

Southwesterly winds will strengthen today, gusting no higher
than 20 kt for most places, but to 25 kt with waves 1-3 ft
around Grand Portage. A Small Craft Advisory has been issued for
this afternoon and early evening. There is a smaller chance
(30%) that gusts could be a little stronger than 20 kt between
Taconite Harbor and Grand Marais, but confidence is higher that
gusts will top out around 20 kt. Winds decrease tonight and
gradually shift in direction Saturday morning to northeasterly
as a backdoor cold front passes through. Winds strengthen to
around 10 kt with gusts to 15 kt Saturday afternoon. There will
be periodic chances for showers and storms on Saturday as the
front passes through.

For the open water discussion, refer to the NWS Marquette Area
Forecast Discussion at weather.gov/mqt.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...Small Craft Advisory until 8 PM CDT this evening for LSZ140.

&&

$$

DISCUSSION...JDS
AVIATION...Britt
MARINE...JDS