Latest Duluth Area Text Forecast Discussion product from NWS:
948
FXUS63 KDLH 281153
AFDDLH
Area Forecast Discussion
National Weather Service Duluth MN
653 AM CDT Mon Apr 28 2025
.KEY MESSAGES...
- Two rounds of thunderstorms are expected today, one in the
morning with a second in the afternoon. Severe storms are
expected with the afternoon round with damaging winds, large
to very large hail, tornadoes and heavy rainfall all
possible.
- Some rain/snow mix may linger tonight as cooler air arrives
behind a cold front.
- Temperatures rebound for the remainder of the week and into
the weekend with the next chance of precipitation arriving
late week.
&&
.DISCUSSION...
Issued at 410 AM CDT Mon Apr 28 2025
High pressure was located over the eastern Great Lakes early
this morning with low pressure in central South Dakota.
Southeasterly return flow was in place across the western Great
Lakes and Upper Midwest, bringing warmer temperatures and
moisture to the region. A southerly low-level jet was also
present and giving rise to some isolated showers and embedded
thunderstorms across the Northland. A larger area of showers and
thunderstorms was located across central and eastern South
Dakota. This area is forecast to lift through the Northland this
morning. These elevated storms may lead to some marginally
severe hail, mainly in the Brainerd Lakes region as they arrive.
As this first round clears the region around midday, questions
remain as to the evolution of the second round of activity for
this afternoon and evening. One of the questions is how much
clearing, if any, will occur in the wake of the first round of
activity. If clouds linger, that would limit how much
instability is able to develop. Should some breaks develop,
daytime heating should lead to pockets of higher instability in
spots across central Minnesota into eastern Minnesota. The
second question is how far north the warm front can push into
the region by this afternoon. Dewpoints will be in the 60s to
the south of the warm front and that is expected to lift north
through much of northwest Wisconsin and eastern Minnesota.
Easterly winds off Lake Superior may slow or stall this
progress and help reinforce it with the cooler air off the lake.
Further, forecast soundings show the presence of a capping
inversion, which may lead to more elevated storms. Some of the
CAMs do not show this capping inversion and keep convection in
the area through much of the afternoon, which may also limit the
max severe potential.
With all that said, the environment south of the warm front is
forecast to be fairly potent. CAPE will be around 1000-1500
J/kg, with effective shear in excess of 40 knots. This may lead
to some isolated cells early on, but quick upscale growth is
expected to a QLCS. Mid-level lapse rates will be around 8 C/km,
which will help with the large hail threat. SRH will be in
excess of 300 m2/s2, so any surface based storm will have the
potential to be tornadic. Looping hodographs in the low levels
support this threat as well. Any bowing segments in the QLCS as
the afternoon evolves will see a higher tornado threat also. The
best estimate for where the warm front will end up roughly along
and south of US2. Areas to the north of US2 will still likely
see storms, but heavy rain will be the primary threat in those
areas with PWATs around 1.25". The second round of activity may
develop as early as 1 to 3 PM in the Brainerd Lakes area,
reaching the I-35 corridor around 4 to 6 PM and possibly
clearing northwest Wisconsin by 9 to 11 PM.
As the low departs to the east tonight, showers will linger on
the backside through the night before slowly ending from west to
east by mid-morning Tuesday. With cooler air pushing in
overnight, some areas of rain/snow mix will be possible across
northeastern Minnesota, but little to no accumulations are
expected. After a warm day today in the 50s and 60s, with a few
70s in far southern areas, Tuesday will be much cooler with
highs in the 40s and 50s. Temperatures quickly rebound for
Wednesday into the 60s for most with 50s in the Arrowhead. Rain
chances return for Thursday into Friday and will keep
temperatures cooler in the 50s and 60s. Early indications are
for a dry and warm weekend with widespread 70s possible by
Sunday.
&&
.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 653 AM CDT Mon Apr 28 2025
MVFR conditions are in place this morning with areas of showers
and thunderstorms. As waves of rainfall move through this
morning, expecting ceilings to further lower to IFR. After the
first round of showers and storms with periods of MVFR to IFR
visibilities, a break is likely during the midday hours before
the next round develops. The second round will likely develop in
the Brainerd Lakes area and work eastward through the afternoon
and into the early evening. Timing on this second round is
still in question as well as severity. If some clearing can
develop between rounds, this second round could be stronger,
especially across southern areas. Large hail, damaging winds
and tornadoes will all be possible with the second round of
storms. Low level wind shear will also affect parts of the
region, namely northwest Wisconsin, as a low level jet and warm
front work through. Wind shear will last longest at HYR with
magnitudes of 30 to 45 knots.
&&
.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 410 AM CDT Mon Apr 28 2025
Southerly winds along the immediate South Shore are expected to
gust to around 25 knots this afternoon and Small Craft
Advisories are in effect for this threat. Periods of showers and
thunderstorms are expected today with the strongest storms
possible this afternoon and early evening. These storms may
contain large hail, damaging winds in excess of 50 knots, and
tornadoes/waterspouts, primarily along the South Shore. A cold
front will move through after the storms with winds becoming
northwesterly in its wake. Wind gusts to 25 to 30 knots will be
possible along parts of the North Shore with a 20 percent chance
for gales in this area during the early morning hours into mid-
morning Tuesday. Small Craft Advisories will likely be needed
for these winds. Winds then diminish Tuesday afternoon and
become light and variable at 10 knots or less Tuesday night.
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 from noon today to 10 PM CDT this evening
for LSZ121-145>148-150.
&&
$$
DISCUSSION...BJH
AVIATION...BJH
MARINE...BJH
NWS DLH Office Area Forecast Discussion
