512
FXUS63 KMPX 211152
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
652 AM CDT Sun Jul 21 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms each afternoon through
  Tuesday will be slow-moving and sub-severe.

- Isolated pockets of heavy rain possible in any slow-moving
  storms, but widespread heavy rain and flooding threat is low.

&&

.DISCUSSION...
Issued at 346 AM CDT Sun Jul 21 2024

Aside from a few showers over western Wisconsin, current temps
ranged in the 60s with calm winds at most observation sites.
Despite tranquil conditions, degraded visibilities across
parts of MN/WI are indicative of developed fog. Additional fog
is expected to spread prior to sunrise with coverage being a bit
more broader as compared to the last two mornings. Visibilities
at times could become less than 1 mile before mixing out later
this morning. An upper low continues to dance north of Lake
Superior with a surface boundary draped across NE MN. This
boundary is progged to slowly track to the south as its parent
upper-level low moves at snail`s pace to the south-southeast.
This means another day of isolated showers and storms are
possible. Isolated morning showers should be confined to western
Wisconsin before additional development occurs from surface
boundary interactions. Latest CAM solutions showing isolated
showers/storms firing ~21z from Alexandria southeast towards Red
Wing. A washout is not expected today however considering the
moisture profile and lack of winds, storms could be slow moving
and produce locally heavy rainfall. Storm organization will lack
once again today due poor deep-layer shear thus, severe weather
is not expected. Otherwise, partly sunny conditions with highs
around the 80 deg mark.

Monday will be similar to today`s forecast as the surface
boundary becomes quasi-stationary. More chances for isolated
showers and storms are expected to develop by Monday afternoon
as an upper- level wave ejects off of the parent upper-level low
just off to its east. By Tuesday a cold front will sweep across
eastern MN and western WI. Total rainfall accumulations
continue to range between a few tenths to near a half inch.
Depending on where the strongest rain falls a few local spots
could observe an inch if not more. After Tuesday`s frontal
passage, the pattern becomes less active with temperatures
slowly creeping their way back into the upper 80s by next
weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 645 AM CDT Sun Jul 21 2024

Early morning convection in far western MN (impacting AXN) and
in western WI (impacting mainly EAU) has at least halted any fog
formation but is resulting in TSRA at the start of this period.
With respect to the fog, that has pretty much stayed away from
the terminals so other than a brief 5-6sm mention at the start,
ground fog is not affecting the MPX terminals this morning.
Still looking for additional periods of convection later this
afternoon at all sites, but the overall duration may end up
being longer than the current PROB30`s indicate (though the
actual thunderstorms moving across a terminal at any given time
would be rather short-lived and intermittent). May well have
MVFR conditions with any TSRA this afternoon, possibly IFR
visibility in any heavy rain. Conditions will improve to VFR
later this evening but additional fog looks likely for early
Monday morning.

KMSP...Both convection and fog have stayed away from MSP this
morning so have initialized with VFR conditions. Still looking
for at least -SHRA to move into the area by early this afternoon
with a window in the mid-to-late afternoon hours for TSRA. The
timing for TSRA may be earlier than the 18z-22z window, and
conditions may be dropped briefly to IFR levels. VFR conditions
are likely this evening into the early morning hours, but ground
fog does look likely overnight through sunrise Monday morning.

/OUTLOOK FOR KMSP/
TUE...VFR, chc -TSRA/MVFR. Wind NW 5-10kts.
WED...VFR. Wind NE 5-10kts.
THU...VFR. Wind SE 5-10kts.

&&

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

&&

$$

DISCUSSION...Dunleavy
AVIATION...JPC