709
FXUS63 KMPX 020804
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
304 AM CDT Thu May 2 2024

.KEY MESSAGES...

- Widespread rain returns to the today. Most areas will see a quarter
  to half inch of rainfall, though amounts closer to an inch
  are possible across SE MN and W WI.

- Unsettled weather pattern brings additional rain chances this
  weekend and early next week.

&&

.DISCUSSION...
Issued at 300 AM CDT Thu May 2 2024

Hopefully folks got a chance to get some fresh air during the mild
and sunny Wednesday afternoon, as today`s weather will take a full
turn in the other direction. No major changes were made to the going
forecast, as widespread rain is on track to arrive this morning,
resulting in a cool, breezy, and soggy Thursday. We`ve knocked highs
down into the low to mid 50s given the expected conditions. The 2 AM
view from the KMPX 88D depicts scattered echoes across much of south
central Minnesota and western Wisconsin. The majority of this early
morning activity is not reaching the surface, given notable low-
level dry air sampled on the 00z MPX RAOB. Latest ACARS data from
MSP Airport reveals that the dry layer is still very much present
over the TC metro, such that it will be another couple of hours
before the atmosphere saturates and raindrops begin to reach the
surface. Observations reflect this idea in west/southwest MN, as a
few hundredths of QPF have been reported thus far. Regional radar
depicts a well defined, expansive precipitation shield lifting to
the north through Iowa at this hour. The shield of rain has
developed ahead of an northward surging warm front, within a region
of broad ascent east of an upper level trough. The combination of
synoptic scale lift and moisture advection into the region will
ultimately be the key players for rain to win out across much of the
area through the morning and start of the afternoon. At the surface,
low pressure is forecast to track from central Iowa towards western
Wisconsin through the course of the day. This storm track will mean
two things for the local forecast: First, thunderstorm chances will
be on the lower side for much of the area, since we`ll be on the
"cooler" side of the storm system. We can`t rule out isolated
thunderstorms in far southern Minnesota and portions of western
Wisconsin, given the potential for a couple hundred joules of MLCAPE
and a plume of steeper lapse rates (7-7.5 C/km) forecast to slide
through this afternoon. Second, the track of the low will mean that
the heaviest rainfall will setup along and southeast of a line from
Fairmont, MN - SE Twin Cities Metro - Barron, WI. In terms of
rainfall amounts, most areas are forecast to observe between a
quarter to half inch, with lower amounts in western Minnesota and
the chance for higher amounts (~1.00"+) along and southeast of the
line mentioned above (due to chance for thunderstorms in this
area). Once the widespread rain ends, we`ll likely have patchy
fog and pockets of drizzle linger for a couple of hours given
saturation in the lower levels captured on forecast soundings.

The upper-level system will lift into southern Canada Friday, which
which will promote broad southwesterly flow into the Upper Midwest.
Though it will be breezy at times, the sunny skies and highs in the
60s to low 70s should make for a nice outdoor day. A quick moving
shortwave will lift through the region early Saturday, which will
bring scattered shower chances for the start of the weekend. This
will not be the same sort of "widespread soaking rain" that is
expected today (and that we`ve seen a few times lately!), rather a
few hundredths to a tenth or so of QPF is expected for the first
half of the day. Dry weather will return from Saturday afternoon
through the end of the weekend, which will set the stage for great
outdoor weather on Sunday, as highs climb back towards 70 degrees
under mostly sunny skies.

Believe it or not, our recent weather rollercoaster takes yet
another dip early next week, as more widespread rainfall is
expected. An upper trough is forecast to become negatively tilted as
it digs into the western CONUS Sunday into Monday. Large scale warm
advection will increase across the Great Plains in response and it`s
likely that temperatures will surge into the mid, perhaps upper 70s
locally on Monday afternoon. The warmth will precede the return of
likely chances for rain and thunderstorms. The period of greatest
potential for rain/stormy activity appears to be later Monday into
early Tuesday morning, ahead of a cold front. While a plume of steep
lapse rates & favorable dynamics will work together to produce the
chance for thunderstorms, the amount of instability will be a key
player in the overall potential for severe weather. Nonetheless,
it`s appearing likely that another round of soaking rain will move
through the region early next week.

The forecast tends to vary a bit more in the extended period given
differences in how models are resolving the progression of the upper-
level low across the northern CONUS through the middle to end of
next week. Given the uncertainty, slight chance to chance PoPs from
the NBM seem reasonable for the middle to end of next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 1059 PM CDT Wed May 1 2024

Rain will move in overnight from the south and ceilings will
lower with MVFR becoming IFR Thursday morning. Visibility should
drop to 2 miles, but could lower even further at times.
Fog/drizzle will develop during the afternoon and linger into
the evening. Winds will be out of the east, with gusts near 20
kts possible. The winds will decrease toward evening and become
light after sunset. There is a chance for thunder, but for
now did not include a mention in the TAFs.


KMSP...
Rain could arrive a bit sooner than the TAF indicates, but it
will be light and VFR. The more steady, heavier rain will lift
up Thursday morning. There is a chance for thunder, but for now
did not include a mention in the TAFs. Expect MVFR/IFR visbys
and ceilings.

/OUTLOOK FOR KMSP/
FRI...VFR. Wind W at 15G25 kts.
SAT...MVFR/-RA with -IFR possible. Wind NW at 10G15 kts.
SUN...VFR. Wind S at 5-10 kts.

&&

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

&&

$$

DISCUSSION...Strus
AVIATION...JRB