173
FXUS63 KMPX 010344
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1044 PM CDT Sun Jun 30 2024

.KEY MESSAGES...

- Best rain chances early in the week come Monday night. Best
  chance for seeing more than an inch of rain will be from
  south central MN toward western WI.

- Thunderstorms and locally heavy rainfall likely for the 4th
  of July.

- For the next week, highs will continue to run a little below
  normal.

&&

.DISCUSSION...
Issued at 405 PM CDT Sun Jun 30 2024

The best way to describe the weather today is perfect. Light
winds, sunny skies, temperatures around 70, and dewpoints in
the 40s have given us a weather day that will be tough top the
rest of the year. Of course all good things must come to an end
and this weather will come to an end tonight as the high
pressure overhead now moves off to the Great Lakes.

Monday and Tuesday... The period that continues to look to have
the most widespread coverage of precip is Monday night as yet
another 50+ kt LLJ moves across MN. We`ll start to have WAA
overspread the area Monday afternoon, but it will be
encountering dry low level air. Because of this, there`s quite a
bit of spread on how quickly rain moves in, with the NAMnest
showing widespread showers across MN Monday afternoon, with
models like the HRRR/ECMWF really holding off on brining precip
into MN until the late afternoon or early evening. The track
record this summer is that if you have the forcing with enough
moisture, you get the rain, so kept an earlier precip mention
going for Monday, following more along with the NAM idea.
Widespread showers and storms are expected Monday night with the
arrival of the LLJ. Guidance continues to show two swaths of
heavier precip Monday night, one up near the international
border with the better forcing and a second from eastern Neb
toward central WI with the better instability. There`s still
spread though on where these heavier regions of rain will exist.
The HREF has the southern rain axis from roughly Omaha to La
Crosse while the ECMWF/EPS have it more from Sioux City to Eau
Claire (with the Euro suite also shifting the northern heavy
rain to the Canadian side of the international border). The
severe risk in the current day 2 period looks pretty minimal in
the MPX area thanks to limited instability, with our greatest
risk of strong to severe storms coming late Monday night in
south central MN as the higher muCAPE values move north across
Iowa with the LLJ. As the previous discussion mentioned, Tuesday
looks to have the more favorable severe setup, but the trend
from the 12z guidance was to shift where the front and LLJ will
be by the afternoon, with the greatest risk for additional heavy
rain and severe weather on Tuesday looking to be just southeast
of the MPX area. For QPF, western through central MN looks to
be in a bit of a lull in the precip, with amounts over the two
days struggling to reach a half inch. Today`s forecast has 1-2"
rainfall amounts along and southeast of a line from Fairmont to
Ladysmith, though given the convective nature of the activity,
the footprint for 1+" rainfall amounts is still likely to shift
some.

Wednesday will be dry, but there will be an h5 trough digging
across the northern Rockies that will become our problem for
Independence Day. This will be a slow moving h5 low that will be
moving across southern MN on Thursday, potentially putting
quite the damper on many 4th of July activities. Precipitation
with this system looks to be driven my more cool season type
mechanisms, with the warm conveyer belt ahead of the h5 low
resulting in a broad area of isentropic lift and frontogenesis.
Because of this forcing, our severe threat is looking low given
the expectations of widespread rain and cloud cover limiting
instability, but it looks like we could see another 0.75-1.5" of
rain out of this, with current trends favoring central MN for
these higher amounts.

We would love to say a stretch of dry weather will follow into
next weekend, but Friday will likely see scattered showers
develop within the cyclonic flow to the west of the low. For the
weekend, the EPS mean h5 heights show troughing remaining in
place through the weekend over the upper MS Valley, so lower
precipitation chances (30s and 40s) remain in place for the
weekend as well, though the signal for severe weather and heavy
rain over the weekend is low.

Next week, trends show us leaning toward northwest flow as upper
ridging builds into the northern Rockies. This would allow
temperatures to at least more frequently hit our normal daily
highs and hopefully give us a weather pattern that will allow us
to slowly dry out.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1026 PM CDT Sun Jun 30 2024

Main issue will be the incoming precipitation expected late
Monday afternoon through Monday night. High clouds will
increase in coverage during the day Monday, with ceilings likely
by midday, gradually lowering to mid-levels Monday afternoon.
Though there may be some timing tweaks done to later TAFs,
confidence is high enough to go right to prevailing precip in
western MN prior to 00z then continuing to the rest of the TAFs
after 00z Monday evening. Ceilings will likely drop into MVFR
range around or shortly after 00z Monday evening, with
visibilities currently advertised into the MVFR range but could
easily be as low as IFR in heavier rainfall. Winds will remain
generally SE throughout this duration, with speeds remaining
under 10kts through sunrise Monday then increasing to 15-20kts
with gusts 25-30kts.

KMSP...VFR conditions to prevail through Monday afternoon, then
conditions are expected to deteriorate quickly Monday evening as
rain/thunderstorms move in from the west. Confidence remains
high enough to maintain prevailing mention for both RA and
CB/TS. Showers could move into the MSP area slightly earlier
than advertised, potentially during the afternoon push. Same
could be said for CB/TS. More tweaking in the precip timing will
be done now that precip is likely within the next 24 hrs.

/OUTLOOK FOR KMSP/
TUE...MVFR. Chance IFR SHRA/TSRA. Wind SW 10-15 kts.
WED...VFR.Wind WSW 15G25 kts.
THU...VFR. Chance MVFR SHRA/TSRA.Wind S 5-10 kts.

&&

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

&&

$$

DISCUSSION...MPG
AVIATION...JPC