391
FXUS63 KMPX 041125
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
625 AM CDT Thu Jul 4 2024

.KEY MESSAGES...

- Thunderstorms and locally heavy rainfall likely today and
  tonight.

- Numerous chances for showers and a few thunderstorms will
  linger into next week with temperatures remaining below
  normal.

&&

.DISCUSSION...
Issued at 402 AM CDT Thu Jul 4 2024

Showers are beginning to advance into and develop across
southwestern MN early this morning. They should reach the Twin
Cities metro in the next few hours. This will be the first of
potentially many rounds during the next 24 hours.

The trough over the northern High Plains will continue digging
southeast this morning, reaching MN this afternoon as a
seasonally potent wave. Forcing will become more focused and a
broad surface low will develop and track across southern MN.
Scattered to numerous thunderstorms are expected by afternoon,
which will continue tonight north of the surface low track and
roughly along the 700 mb low track. This favored area is
expected to stretch from the Redwood Falls area to the Twin
Cities metro. 00Z HREF neighborhood probabilities of greater
than 2 inches within this corridor range from 60 to 80 percent,
and 30 to 60 percent for greater than 3 inches. That`s a strong
signal for heavy rainfall, but there are some limiting factors
to consider for flooding. Many of the CAMs and even the global
guidance indicate rain will not be continuous for several hours.
There should be breaks between rounds which will allow runoff
from becoming excessive. Pwats aren`t too anomalous for this
time of year and rain rates aren`t expected to be too extreme
either. Perhaps some 1-1.5 inch/hr rates will be possible with
the most robust convection, but 1 hr flash flood guidance values
are generally 1.5-2 inches and those rates shouldn`t last an
hour`s time. Areas that do see totals of 3 inches through Friday
morning may have some issues, but these pockets should be
fairly localized. For these reasons, decided against a Flood
Watch at this time but trends will continue to be monitored.

Mid level lapse rates will remain modest and the prospects of
significant surface heating still appear limited given the
extensive cloud cover, so instability will be lacking in most
locations. However, across southern MN there may be better
heating near and south of the low track. Here, there is some
potential for a few stronger storms where CAPE may exceed 1000
J/kg and deep layer shear is better. Some marginally severe
hail and a couple weak tornadoes are possible.

The showers will linger into Friday across eastern MN/WI, but
some scattered activity could redevelop farther west in the
afternoon with breaks in the clouds and some instability
developing within the cyclonic flow.

Multiple waves within a broad north central U.S. trough will
keep precip chances going for much of the remainder of the
period. Nothing looks particularly widespread or heavy, but it
will continue the gloomy and un-Julylike weather for the
region. Temperatures will remain below normal until if/when the
western Ridge builds east. Some of the extended guidance is
hinting at that possibility toward mid-July.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 611 AM CDT Thu Jul 4 2024

Light rain and a few rumbles of thunder will move across MN & WI
for a few hours this morning, but no vis/cig restrictions are
expected. Scattered showers and thunderstorms develop late this
morning across western MN & will continue on & off into Monday
morning. The most widespread coverage of showers, & highest
likelihood of thunderstorms, will be from early afternoon into
this evening. Mainly MVFR visibility is expected with the rain
showers this afternoon, but brief IFR visibility is possible
with any thunderstorms. A bit of a lull is expected in the
precipitation this evening & tonight, before rain showers become
more widespread again overnight into tomorrow morning. Ceilings
will lower this afternoon & evening as the rain begins, with
most locations becoming MVFR by this evening ^ potentially IFR
overnight.

Winds will be light and variable through the day with a surface
low overhead but will generally be southeasterly to easterly
this morning, and eventually northerly to northwesterly tonight
into tomorrow morning.



KMSP...A few hours of light rain this morning with no
visibility reductions expected, but a rumble of thunder or two
can`t be ruled out. Showers and thunderstorms look to become
more widespread by 2-3 PM with the best chance for
thunderstorms and heavy IFR rain from late afternoon into early
evening. Showers will become more isolated and likely end for a
few hours after 7-8 PM, with another round of scattered showers
developing overnight into tomorrow morning. Ceilings will drop
below the 017 threshold by this evening & will likely become IFR
late tonight into tomorrow morning.

/OUTLOOK FOR KMSP/
FRI PM...Chance MVFR -SHRA Wind N 10-20 kts.
SAT...Chance PM MVFR SHRA/TSRA. Wind SW 5-10 kts.
SUN...MVFR/SHRA/TSRA likely. Wind SW 10-20 kts.

&&

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

&&

$$

DISCUSSION...Borghoff
AVIATION...ETA