074
FXUS63 KMPX 301927
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
227 PM CDT Mon Jun 30 2025

.KEY MESSAGES...

- Isolated showers and thunderstorms this afternoon and evening,
diminishing after sunset.

- Airmass storms possible again on Wednesday, better chance for
  showers/storms arrives Friday into Saturday.

&&

.DISCUSSION...
Issued at 226 PM CDT Mon Jun 30 2025

Aggravated cumulus over far eastern MN into the St. Croix valley
have bubbled since 1pm, resulting in a few storms developing near
New Richmond moving eastwards with a fair bit of lightning to speak
of as well as brief heavy rain. Further airmass type storms are
expected this afternoon into the evening before falling back as we
lose our instability after sunset, with regional radar showing a
broad area of scattered showers and weak storms throughout the
northern half of Minnesota to this point. We do not anticipate any
severe weather from these storms with a few cells capable of
producing some small hail alongside heavy rain with limited shear to
maintain storm intensity for a long duration, with the main concern
being lightning for anyone doing outdoor activities.

After the shortwave pushes through this evening, the broad section
of the trough slides over the Great Lakes with northwesterly winds
aloft and weak high pressure moving into the region. Tuesday looks
to be a top 10 weather day with plenty of sunshine and temperatures
in the low to mid 80s alongside northwesterly winds at 5-10mph with
some fair weather cumulus during the afternoon. Synoptic guidance
favors a shortwave moving across the southern edge of the forecast
area on Wednesday afternoon resulting in another chance for some
showers and storms. NAM forecast soundings in southern MN from 18-
00z Wednesday show a sizable 100-150 cap amidst a meager 1000-1500
J/KG MLCAPE with poor low level shear that only becomes sizable
towards the top 100mb of the troposphere. Lapse rates are decent
enough where if we end up getting a couple storms to form, we could
see isolated hail and some frequent lightning with other storm risks
largely absent.

Thursday will see the apex of the ridge slide over the northern
plains with weak subsidence returning resulting in yet another
beautiful day of low to mid 80s with a breeze and fair weather
clouds. The July 4th holiday on Friday still appears to be the best
overall environment for showers and storms this week with most of
the mid to long range guidance showing a broad trough with embedded
shortwaves pushing across the area by Friday evening which would
result in increased cloud cover as well as showers and storms. The
synoptic setup is the best we will see from a forcing perspective
due to the trough and also the nose of a low level jet developing
over the Dakotas by the evening, however the placement of the jet
will be crucial in firing off storms in the better daytime
environment before they migrate towards Minnesota and Wisconsin.
Forecast soundings from 21-06z Friday afternoon into Saturday
morning show a weak cap due to the incoming low level jet coupled
with mediocre shear and enough instability to produce storms,
however the overall environment leaves much to be desired from a
severe thunderstorm perspective. The heavy rain threat appears to be
higher with PWAT values in the GFS over 2 inches amidst an overall
saturated troposphere. While the environment does not completely
skunk chances for fireworks viewing, the increase in cloud cover as
well as chances for showers will put a damper on many plans.

As the shortwave trough pushes out of the area on Saturday, flow
aloft returns to zonal with chances for shortwaves and more airmass
type storms continuing into early next week. Our overall unsettled
pattern looks to continue albeit without significant synoptic
forcing. We will once again proceed with a relatively low confidence
forecast much like we have been experiencing lately with the 2-3 day
window as more mid range and CAM guidance comes into play crucial
for resolving any thunderstorm chances moving forward into the first
full week of July.&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1229 PM CDT Mon Jun 30 2025

Mainly VFR throughout this TAF duration with main chances for
MVFR/TSRA for sites along and north of I-94, generally in the
20z-00z timeframe this afternoon. Chances for precip are still
only in the 30 percent area, not high enough for TEMPO
confidence so have kept PROB30 mention going. Otherwise, mainly
high clouds with some diurnal mid- level cumulus development,
then clearing tonight through Tuesday morning. NW winds will be
breezy/gusty through sunset then diminish to 10kts or less this
evening through the overnight hours.

KMSP...Chance of a late afternoon SHRA/TSRA, generally the
20z-23z timeframe, with MVFR conditions possible. Otherwise, VFR
conditions to prevail with NW winds throughout this duration.

/OUTLOOK FOR KMSP/
WED...VFR. Slight chance TSRA/MVFR. Wind SW 5-10 kts.
THU...VFR. Slight chance TSRA/MVFR. Wind SSE 5-10 kts.
FRI...Chance aftn TSRA/MVFR, likely evening TSRA/MVFR. Wind S
10-15 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.

&&

$$

DISCUSSION...TDH
AVIATION...JPC