673
FXUS63 KMPX 160859
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
359 AM CDT Sun Jun 16 2024

.KEY MESSAGES...

- Showers and thunderstorms will diminish early this morning. Hot
  and very humid today with heat indices peaking near 100
  across eastern/southern MN into WI. A Heat Advisory remains in
  effect for the Twin Cities metro.

- A front will stall across southern Minnesota tonight, focusing
  the next round of heavy showers and thunderstorms along it
  through Monday. A few more inches of rain may fall in places,
  posing a flash flood threat. Isolated severe storms are
  possible.

- Front lifts north Monday night with the main heavy rain
  threat area refocusing across northern and central Minnesota.
  A Moderate Risk of flash flooding remains in this area.

- Additional showers and storms will develop along a cold front
  Tuesday. A few severe storms and more heavy rain will
  accompany this round.

&&

.DISCUSSION...
Issued at 359 AM CDT Sun Jun 16 2024

An MCV northeast of the Twin Cities is heading east early this
morning. Showers and thunderstorms are gradually diminishing
from west to east and cloud tops are warming quickly. The
ongoing convection across southern MN is more disorganized than
it was earlier, but still poses a low risk for flooding for the
next hour or so due to 1 to 2 inch per hour rates. Clouds are
clearing across western MN and eastern SD, setting the stage for
a hot and very humid day. A warm front will lift north this
morning and thermal ridging will build up ahead of a cold front
set to move in this afternoon. 925 mb temps of +25 to +27 still
suggest highs near 90 across southern/eastern MN into WI. Dew
point pooling will occur as the front approaches this afternoon,
aided by the last 24 hours of rain. Readings could reach the mid
70s. Combined with temperatures near 90, heat indices will peak
around 100 and thus a Heat Advisory remains in effect for the
Twin Cities metro this afternoon. Despite the high dew points,
the atmosphere will remain capped today due to a stout elevated
mixed layer, so convective redevelopment today is unlikely.

The cold front will stall near the IA/MN border tonight and
remain there through Monday. Steep lapse rates will remain
through much of the night and the atmosphere will remain capped.
However, an increasing LLJ across the Plains will spark
elevated thunderstorm development first over SD and Neb this
evening, then as some veering of the jet occurs overnight into
western IA, activity will spread across MN. Some large hail
could accompany storms. The larger threat though will be another
round of heavy rain. The LLJ won`t be particularly strong, but
continued development and training of convection north of the
stalled front, very high pwats around 2 inches, and primed soil
from yesterday`s activity, will enhance the threat for flash
flooding. It`s a little peculiar CAMs and global models aren`t a
little more robust with QPF given the set up, although the 06Z
HRRR does have some 2 to 4 inch totals across west central MN. A
Flood Watch may eventually be needed once confidence in spatial
placement of the heaviest QPF with tonight`s round increases.

The front won`t move much or at all most of Monday. Continued
development of thunderstorms should occur in much of the same
areas as tonight. As the trough begins to head northeast across
the Plains later in the day, the LLJ will strengthen and
moisture transport will maximize. This will allow more robust
development to occur across central MN with another 2 or 3
inches possible in spots. Some large hail could also accompany
the stronger cores. Despite the widespread precip north of the
front, the ejection of the system northward and very strong WAA
will push the warm front, and thus the zone of heavy rainfall,
north quickly Monday night. After a coolish day, the passage of
the warm front will send temperatures into the mid 70s Monday
night.

By Tuesday, the trailing cold front will push through. Strong
forcing along the front and a very moist and unstable airmass
ahead of it will produce a band of showers and thunderstorms
along it. A relatively slow progression will lead to yet another
threat for strong/severe storms, and heavy rain and flooding
through Tuesday evening.

The front will stall Wednesday southeast of the area, but it may
be near enough for additional showers across southern MN into
parts of central and western WI. A return of it northward
Thursday and Friday with the approach of the next system will
bring increased chances for more storms.

By the time we reach late week, most of the area will likely see
an additional 3 to 5 inches of rain. Some localized areas will
be heavier, of course. The risk for river flooding is still
being assessed and will depend on each round going forward, but
it`s safe to say increases can be expected and several locations
will likely rise to flood stage in the coming days.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1239 AM CDT Sun Jun 16 2024

Scattered thunderstorms have congealed into an expansive area of
light to moderate rain showers, with isolated thunder embedded
throughout. There are pockets of MVFR/IFR cigs associated with
this area of precip. This rain will gradually push east out of
the area throughout the early morning, giving way to mostly VFR
conditions today. Winds will persist around 5-10kts and will
turn more southerly this morning, before shifting southwesterly
in the afternoon and eventually more northerly late this
evening.

KMSP...Pockets of heavy rain will continue for the next hour or
two, with isolated thunder nearby. A line of stronger thunderstorms
is tracking eastward across central Minnesota, producing
rainfall rates of 2-3"/hr and reducing visibilities down to
1 1/2SM at times. Recent radar data shows this line starting to
fall apart and moving eastward faster within the past hour,
however there will likely still be an impact from it for a
couple hours early this morning. As this line of moves out,
things should be quiet until later tonight when the next wave of
thunderstorms develop. Winds will be around 10-15kts today,
slowly shifting from the south to more southwesterly this
afternoon and eventually northerly overnight.

/OUTLOOK FOR KMSP/
MON...VFR, likely MVFR/IFR/TSRA PM. Wind SE 10-15kt.
TUE...VFR, likely MVFR/IFR/TSRA PM. Wind S 10-15G25-30kts.
WED...VFR/MVFR/-SHRA, chc -TSRA PM. Wind N 5-10kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Heat Advisory from 1 PM this afternoon to 7 PM CDT this
     evening for Anoka-Carver-Dakota-Hennepin-Ramsey-Scott-
     Washington.
WI...None.

&&

$$

DISCUSSION...Borghoff
AVIATION...BED