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000
FXUS63 KDLH 261726
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1226 PM CDT Fri Apr 26 2024

.KEY MESSAGES...

- Wet conditions are expected today, through the weekend, and
  into Monday as back-to-back Colorado Lows move through. Total
  rainfall amounts around 1-2" is expected from both of these
  systems.

- Embedded thunderstorms will be possible today through the
  weekend. Severe thunderstorm potential has decreased as the
  low pressure track on Saturday has shifted slightly to the
  southeast.

- Expect breezy to strong northeast to east winds on Sunday
  afternoon and evening as the second Colorado Low moves
  through. A Wind Advisory may be needed, especially along the
  North Shore.

&&

.DISCUSSION...
Issued at 426 AM CDT Fri Apr 26 2024

Widespread rain will be arriving into the CWA today as a deep
Colorado Low propagates towards the upper Midwest. Expect cloud
cover to increase from southwest to northeast this morning ahead of
the approaching low pressure. A strong low-level jet up to 50 knots
extending from the Gulf of Mexico into southern Ontario will be
bringing deep moisture advection and a period of prolonged rainfall.
Expect rain to being from southwest to northeast through the day
today, initially falling as virga for the first couple hours as
low-level dry air lingers from departing high pressure.

Widespread scattered showers will be persisting tonight into
tomorrow as the Colorado Low center crosses over northwest Wisconsin
on Saturday morning into early Saturday afternoon. Embedded
thunderstorms will be possible starting this afternoon around the
Brainerd Lakes, expanding to encompass much of the CWA this evening
into tonight. Instability will be fairly weak with around 100-200
J/kg of MUCAPE combined with around 30 knots of 0-6 km bulk shear.
Given the weak instability and marginal mid-level lapse rates around
7 degC/km, severe weather is not expected today into tonight. Severe
thunderstorm potential has also decreased for Saturday in northwest
WI. A slight southeast shift in the low pressure track from recent
model runs now places the region of best CAPE east of the CWA.

Expect a brief break from the widespread rain to occur Saturday
evening into Sunday morning as today`s Colorado Low propagates
downstream. A second Colorado Low is expected to undergo
cyclogenesis on Saturday as a deep trough propagates through the
Rocky Mountains. This second Colorado Low is very likely to
follow a similar path to today`s system with time of arrival
into the upper Midwest progged to be Sunday. While the LLJ
providing moisture advection from the Gulf of Mexico won`t be as
strong with this second system, total QPF is forecast to be
similar. In total, both systems will be bringing 1-2" of
rainfall across the entire CWA. Locally higher amounts up to
2.25" may be possible, most notably along the North Shore as
orographic enhancement occurs from strong northeast winds on
Sunday. It is worth noting that while run-to-run model
variations in total QPF have been fairly stable, there has been
a slight decrease in total QPF. Flooding concerns are minimal,
as this soaking rain will be occurring over a prolonged period
and antecedent conditions are fairly dry.

While flooding and severe weather concerns are minimal to none for
Sunday`s low pressure, one concern will be strong northeast to east
winds. There is a 50% chance that east to northeast wind gusts along
the North Shore on Sunday afternoon into Sunday evening will reach
Wind Advisory criteria. One impact that is much more certain on
Sunday will be cool high temps. Highs on Sunday were lowered from
the NBM as strong onshore flow from Lake Superior will likely advect
cold air inland.

The pattern will remain active following the departure of the second
Colorado Low on Monday evening. Zonal flow aloft at 250mb over the
upper CONUS will likely result in a series of shortwaves propagating
through. Additional chances for rain arrive Tuesday afternoon and
continue periodically into next week Friday. High temps will be
trending warmer next week, reaching around 5 to 10 degrees above
normal for early May.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1226 PM CDT Fri Apr 26 2024

VFR conditions for most terminals will continue to degrade through
the afternoon and evening, coming down to MVFR and IFR visibilities
and ceilings as rain becomes more widespread across the region. At
BRD, where a band of rain already moved across, conditions may
improve for a couple hours before degrading again. Some LIFR
ceilings may be possible overnight into Saturday morning. Southwest
winds remain strong through this evening before slowly weakening
into Saturday morning. Saturday morning, conditions will begin to
improve slowly, most likely at BRD and HYR by mid morning
tomorrow.

&&

.MARINE...
Issued at 426 AM CDT Fri Apr 26 2024

Low pressure will develop over eastern Colorado and move towards
western Lake Superior today. As the low enters the region today into
Saturday, winds will be increasing out of the east to northeast at
15 to 25 knots with gusts to around 30 knots. Waves will also be
building in excess of 4 feet along the North Shore and western side
of the Apostle Islands and Bayfield Peninsula. A Small Craft
Advisory has been issued for portions of western Lake Superior
starting this afternoon and continuing into Saturday afternoon.

Winds will weaken a bit Saturday afternoon and Saturday night as the
low passes. A second low pressure arriving on Sunday will once again
increase winds from the east to northeast with gales very likely
(80% chance) for Sunday into Monday morning. There is also a low
chance (20% chance) for brief storm-force gusts on Sunday evening
along the North Shore. A Gale Watch has been issued for all of
western Lake Superior starting Sunday morning and continuing into
early Monday morning. Make sure to monitor the forecast for a
potential upgrade to a Gale Warning.

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...Gale Watch from Sunday morning through Monday morning for
     LSZ121-140>143-146>148-150.
     Small Craft Advisory until 4 PM CDT Saturday for LSZ140>142.
     Small Craft Advisory until 4 PM CDT Saturday for LSZ143>145.
     Gale Watch from Sunday morning through Monday morning for
     LSZ144-145.
     Small Craft Advisory from 10 PM this evening to 4 PM CDT
     Saturday for LSZ146-147-150.

&&

$$

DISCUSSION...Unruh
AVIATION...Levens
MARINE...Unruh