882
FXUS63 KMPX 210612
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
112 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 214 PM CDT Sat Jul 20 2024

Interesting meteorological setup today with an upper low over
Iowa atop a surface high over the same spot. The main result of
this superposition is some isolated to scattered showers and
thunderstorms in the vicinity of the upper low while deep-layer
shear remains very weak, thus keeping any storms poorly
organized and short-lived. While this means a rather low threat
for any strong or severe storms, a few localized sub-severe
gusts can`t be ruled out, along with some very isolated pockets
of heavier rain if a storm happens to sit over one location for
a period of time. The main focus for this activity will be
across southern Minnesota in closer vicinity to the upper low,
as well as near/just north of the I-94 corridor near a weak
southward-advancing low-level boundary.

After some areas of morning fog on Sunday, expect much of the
same during the afternoon with isolated to scattered afternoon
pulse thunderstorms developing in the vicinity of a weak upper
wave dropping in from the north. Once again parameters will
favor short-lived sub-severe storms with a few pockets of
heavier rainfall possible, but otherwise no widespread hazards
expected. This copy-paste pattern will continue into Monday and
Tuesday, with perhaps slightly less coverage on Monday and
slightly higher on Tuesday when a cold front will provide a bit
more focus for forcing. While the slow-moving nature of these
storms could produce an inch or so of rain over a couple of
spots, widespread rainfall amounts will average out to be rather
low, and therefore will result in few if any impacts to river
levels. Things will dry out behind Tuesday`s front while
temperatures stay fairly close to seasonal averages.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 104 AM CDT Sun Jul 21 2024

Models continue to try hitting all sites hard for fog this
morning but have maintained a more conservative approach with
TEMPOs for the lowest conditions with MVFR-worthy visibility
prevailing in the pre-dawn hours through daybreak. VFR
conditions likely throughout the day today into this evening,
but there is again the lingering chances for afternoon-evening
TSRA. Have made only a few tweaks to the timing of the PROB30s
otherwise kept that mention going since, again, confidence is
rather low on the placement of any diurnal convection. Slightly
higher chances for more persistent SHRA in far eastern MN into
western WI so did add a mention of prevailing showers but kept
the PROB30s going there as well for any TSRA. Winds continue to
be light and variable.

KMSP...VFR to start with ground fog setting in a couple hours
prior to sunrise. Can`t rule out IFR-or-worse conditions but
chances are fairly low. Otherwise, the main issues surround the
timing of any afternoon-evening TSRA. Best timing looks to be in
the early-mid afternoon hours, as opposed to later, for any
thunderstorms but given the larger surrounding window of
prevailing showers, the window for having thunderstorms may vary
from the currently-advertised 18z-22z. Once precip ends this
evening and skies become partially clear, fog looks to once
again develop early Monday morning. Have kept visibility as MVFR
at this point but later TAFs could lower that visibility.

/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...DPH
AVIATION...JPC