711
FXUS63 KMPX 281134
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
634 AM CDT Fri Jun 28 2024

.KEY MESSAGES...

- Showers & thunderstorms move across Minnesota & Wisconsin this
  morning. Rainfall amounts around 0.5" are expected, with
  amounts closer to 1" across central Minnesota.

- Dry this weekend, with the next round of widespread rain
  coming Monday. Heavy rain & severe thunderstorms are possible.

&&

.DISCUSSION...
Issued at 323 AM CDT Fri Jun 28 2024

Warm-air advection driven showers and thunderstorms continue
overnight across the eastern half of Minnesota & western
Wisconsin, while a decaying MCS also enters western Minnesota &
move eastwards through the morning. MLCAPE values fall off
greatly along the MN/SD so we`re not expecting anything strong
or severe out of the MCS, but MUCAPE values near 1000 J/kg
extending all the way to the MN/WI border mean the complex
should hold together through the morning. The MCS will take over
as the primary driver of precipitation this morning as it
overruns the WAA-driven precip, with the rain coming to an end
by 8-9 AM across eastern Minnesota & by late morning across
western Wisconsin. Widespread rainfall amounts around 0.5" are
generally expected, but amounts closer to 1" are likely across
central Minnesota where the WAA-driven precip overnight has been
more widespread.

While the rain comes to and relatively early in the day,
forecast soundings show plenty of boundary-layer moisture which
will result in low cloud cover sticking around through much of
the afternoon. This will limit instability for a potential
second wave of thunderstorms as the surface cold front moves
through the area during the afternoon. The widespread cloud
cover in addition to a weakening surface low means the threat
for severe thunderstorms, let alone any thunderstorm
development, continues to trend lower with the SPC downgrading
our area to a Marginal Risk. A few CAMs still initiate cluster
of thunderstorms across far-southern Minnesota so the threat
can`t be totally ruled out, but most locations can probably bet
on staying dry this afternoon once the morning precipitation
ends.

Shower and thunderstorm chances look a little more likely late
tonight across central Minnesota as a compact shortwave pivots
through the region. Most CAMS are in agreement with initiates
isolated to scattered thunderstorms with this feature, mainly
north of I-94. Shear values will be quite high overnight so a
few organized cells can`t be ruled out with a threat for
isolated hail.

Dry & pleasant weather is expected this weekend as high
pressure builds over the region behind today`s system.
Temperatures will be on the cooler end for late June with
daytime highs only expected to be in the low 70s. Sunday morning
looks to be seasonably chilly as well with lows dropping well
into the 40s, & a non-zero chance at very patchy frost wherever
the core of the high sets up across northern MN/northern WI.

The dry break will be short-lived however, as the upper-air
pattern becomes more active & a surface low out of the central
plains brings another round of widespread soaking rainfall
Monday through Tuesday. Ensemble mean Precipitable water values
approach 2" across southern Minnesota & NBM/ensemble guidance
show probabilities over 50% for rainfall amounts exceeding 1".
Exact rainfall amounts still depend on the track & timing of
the system, & whether any boundaries can develop for storms to
train along, but the rainfall amounts will have to be watched
Monday for additional flooding impacts. An environment
supportive of strong or severe thunderstorms is also likely
wherever the surface low ends up during the afternoon & early
evening, although confidence in the timing of the system remains
low at the moment.

The pattern has the potential to remain active through the rest
of the week, although models diverge on when & where any
shortwaves develop & generate additional precipitation tracks.
Midweek generally favors drier conditions but precipitation
chances ramp up again later in the week. Temperatures will
generally be close to normal with highs in the upper 70s to low
80s along with muggy dew points.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 633 AM CDT Fri Jun 28 2024

An area of showers with some embedded thunderstorms has been
moving across Minnesota and western Wisconsin this morning. By
the issuance time of the 12Z TAF most Minnesota terminals will
be done with the most impactful part with only some lingering
rain showers. Low ceilings will persist through the morning
with low MVFR to high IFR ceilings. The heaviest rain will move
into the Wisconsin terminals next, but it is moving fast with
only an hour of heavy rainfall. This afternoon ceilings should
start to rise once again with VFR by tonight. Another round of
thunderstorms is possible this afternoon and evening. Best
chances will be in southern Minnesota into adjacent parts of
western Wisconsin. So MKT and EAU have the best chance, although
it is farther south over Iowa where the better chances are.
Winds will be gusty in the 20 to 30 knot range on the back side
of the rain, before calming later today.

KMSP... Most of the rain is now finished with just some
lingering showers through 13Z. Low MVFR to high IFR is expected
with southerly winds gusting up to around 20 knots. We are
forecasting a southwest wind this afternoon which could be a
crosswind for the open parallel runway. Thankfully winds should
be lighter by then and not as impactful. While the best chances
for afternoon thunderstorms are to the south there is still a
chance. With the probability of this occurring under 30 percent
it was excluded from the TAF. If chances increase, look for the
inclusion of TSRA on future amendments.

/OUTLOOK FOR KMSP/
SAT PM...VFR. Wind N 5-10 kts.
SUN...VFR. Wind N bcmg E 5-10 kts.
MON...VFR/MVFR, RA likely, chc -TSRA. Wind SE 10-15G25 kts.

&&

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

&&

$$

DISCUSSION...ETA
AVIATION...NDC