390
FXUS63 KDLH 281152
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
652 AM CDT Fri Jun 28 2024

.KEY MESSAGES...

- Widespread moderate to locally heavy rainfall will continue
  to affect the area this morning before moving out this
  afternoon.

- Isolated severe thunderstorms are possible (5% chance) in
  central Minnesota and northwest Wisconsin this afternoon and
  evening.

- Residual showers Saturday in northeast Minnesota give way to
  a dry Sunday before the next round of moderate to locally
  heavy rainfall is forecast to return Monday into Tuesday.

&&

.DISCUSSION...
Issued at 512 AM CDT Fri Jun 28 2024

A warm front is pushing into the area early this morning, with
a broad band of showers and embedded thunder expected to move
from southwest to northeast across the area this morning. Cloud
tops have been warming and lightning frequency has been
dropping, in combination with the generally weakening radar
echoes. The moist southerly advection accompanying this front
has brought precipitable water values of 1.6 inches to MPX which
is over the 90th percentile. The Precipitable Water value for
INL was much lower at 00z, but model sounding imply values
around 1.5 inches by 12z, which would also be above the 90th
percentile for this date. The last few days we have been trying
to nail down the location of the warm front, which should help
us sort out where the highest rainfall totals will be. The warm
front has become difficult to define, with the WPC analysis
putting one from the low center over eastern S.D. extending
southeast into IA and MO, so that is not much help. There is a
pretty large dewpoint gradient from south to north across the
CWA along with a subtle backing of wind, which may help focus
precipitation later today. For now the heavier precipitation
appears to be focused in the higher dewpoint air south of that
boundary, focused on the nose of the low level jet and in the
plume of 850mb moisture and in the best moisture and thermal
advection. Once this initial surge of showers and storms moves
across the area, we expect an area of instability to arrow into
northwest Minnesota this afternoon, with somewhat favorable mid-
level lapse rates aligning along the highest instability axis to
support a small severe weather threat into north-central
Minnesota by the late afternoon to evening hours. Model forecast
soundings show that the window of potential severe storms is
going to be rather narrow, with the area of greatest instability
of around 1000 J/kg CAPE in that area of at least 6.5 C/km mid
level lapse rates. The deep layer shear is strong, but the low
level shear parameters are too messy for the best setup. Do not
have concerns for much more than scattered strong to near-severe
thunderstorms for the Brainerd Lakes east across Pine county
into the westernmost portions of northwest WI. Lingering showers
with only a little thunder to linger behind the main cold front
overnight tonight. Diurnally driven showers and isolated
thunderstorms are favored Saturday afternoon and early evening
in the cyclonic flow behind the cold front, but severe
thunderstorms are unlikely.

We have been watching another round of showers and
thunderstorms which are expected to move through the area Monday
through Tuesday. There may be a period of storms with locally
heavy rainfall Monday evening, but it appears any severe storm
risk will stay west of the forecast area. Tuesday we may develop
enough instability for stronger storms, but that is going to
depend on the timing of this system as it moves through the
area. This system is a fairly potent upper level shortwave that
moves through, and it is part of a broader upper level trough
that settles over the central CONUS for much of the upcoming
week. This will keep smaller precipitation chances going through
the week, but no single feature to focus on for higher precip
chances.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 652 AM CDT Fri Jun 28 2024

A wave of showers and embedded thunderstorms is sliding across
the area this morning, with IFR ceilings and MVFR visibilities
affecting most of the terminals as it moves across. Brief LIFR
conditions are possible, but should not be widespread. As the
rain moves out later this morning expect visibilities to improve
to VFR, and ceilings may improve to MVFR, but no significant
improvement in ceilings is expected until late this afternoon.
There should also be a period of scattered shower and
thunderstorm activity for this afternoon and evening with brief
periods of lower conditions. Stratus will move back into some of
the terminals this evening with MVFR conditions developing after
00z. Gusty south to southeast winds of 20 to 25 kts this morning
to slowly veer to southwest and west by late this afternoon,
before becoming northwest this evening.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 512 AM CDT Fri Jun 28 2024

An approaching low pressure system has causing northeast winds
to increase on the lake early this morning, which should back
into the southeast to even south this morning. Speeds of 10 to
15 knots will gust around 25 knots later this morning through
the afternoon, then decrease again this evening. There will be
several hours of hazardous conditions for small craft, and have
issued a Small Craft Advisory for parts of the lake. Shower and
storms have been moving in overnight, and will remain likely
this morning before diminishing to scattered showers and
isolated storms for the afternoon and evening. Small chances of
showers and storms will linger tonight and Saturday. The cold
front with these storms Friday night will cause winds to switch
to westerly, then increase again for Saturday before diminishing
into Saturday night and Sunday. For now it does not appear
hazardous conditions will develop on Saturday, but this may
change.

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 10 AM this morning to 4 PM CDT this
     afternoon for LSZ121-140-144>148-150.

&&

$$

DISCUSSION...LE
AVIATION...LE
MARINE...LE