850
FXUS63 KMPX 041757
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1257 PM CDT Sat May 4 2024

.KEY MESSAGES...

- Rain showers this morning. Rainfall amounts of a tenth to a
  quarter of an inch expected.

- Another round of showers and thunderstorms likely Monday
  night into Tuesday morning.

&&

.DISCUSSION...
Issued at 334 AM CDT Sat May 4 2024

Rain showers continue to slowly spread eastwards out of western
Minnesota overnight. The MCS over Nebraska has taken on a more
easterly track into Iowa, meaning the trend towards heavier
precipitation & possible thunderstorms over southern Minnesota
no longer is expected. Most locations will see between a tenth
to a quarter inch of rain as the band of showers north of the
convective complex migrates east across the area. A few hours of
rain is expected, with the rain ending by mid-morning across
central MN, late morning/early afternoon for eastern Minnesota,
& by mid-afternoon for western Wisconsin. Skies will slowly
clear out after the rain, so a sunny afternoon or early evening
still looks salvageable for areas east of the St. Croix River.
The rain and clouds will keep temperatures cool this afternoon,
generally around 60 degrees.

Drier, sunny, & warm weather is expected Sunday into Monday as
high pressure moves over the region. High temperatures around
low 70 are likely, potentially warming into the mid to upper
70s Monday with some compressional warming possible ahead of an
approaching front. Winds will be relatively light on Sunday with
the high overhead, but increase through the day on Monday as
the pressure gradient increases ahead of the approaching front.
Southeasterly winds could gust as high as 40-50 mph late Monday
afternoon & evening across western Minnesota, in response to the
surface low deepening into the low 980s mb over the northern
Plains.

A band of showers an thunderstorms is expected to develop along
the front extending ahead of this deepening surface low, with
ensemble guidance showing a very high likelihood (>90%) of
precipitation occurring across the entire area. Strong dynamics
will be present with this system with surface winds gusting to
40-50 mph along of the front & bulk shear values of 50-60 kts.
However, instability will be lacking this far north across the
Dakotas & western Minnesota, further exacerbated by the fact
that the model consensus brings the front & thunderstorms
through the area late Monday night & overnight into Tuesday
morning. The threat for damaging winds isn`t negligible given
the strong background surface winds, but for now the severe
threat looks to mainly develop across the central Plains & mid-
Mississippi valley. Ensemble guidance generally shows rainfall
amounts between 0.5-1" across the entire area, mainly owing to
the forecast quick progression of the storms across the area.
Amounts over an inch are still possible if the system slows
somewhat between now & Monday night. In general, thunderstorms &
another soaking rain look a like a sure bet Monday night.

Beyond Tuesday, the upper-air pattern remains active as the
upper-level low responsible for the Monday-Tuesday system stalls
out, & potential becomes cutoff over the Great Lakes. A number
of weak disturbances pivot around this broad area of low
pressure as a result, meaning multiple chances for generally
light rain through the end of the week. Model consensus in
timing any of these disturbances is low so a generic broad ~30%
chance for rain exists pretty much exists for Wed-Fri.
Temperatures will be cooler as well with lower heights over the
region, with daytime highs generally in the low 60s. The upper-
level low finally exits the Great Lakes region over the weekend,
with likely a return to drier & more seasonable weather.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1244 PM CDT Sat May 4 2024

Main swath of rain has shifted off to the east, thus outside of
potentially a brief lingering sprinkle/shower in far eastern MN
into western WI, no additional precipitation is expected this
duration. Visible satellite imagery shows the stratus deck
continuing to slide eastward, with it still holding east of a
line from Princeton to Mankato, while points west are breaking
out with fair wx cumulus clouds. One by one, TAF sites will have
their ceilings erode away to VFR cumulus this afternoon,
followed by clearing overnight through Sunday. Breezy NW winds
at initialization will diminish this evening then go
light/variable overnight through daybreak and into late Sunday
morning. For much of central-eastern MN into western WI, a
period of pre-dawn MVFR-worthy ground fog is looking likely at
the TAF sites early Sunday morning but this should be of limited
impact.

KMSP...Low/MVFR stratus looks to hold on through about 20z, with
VFR conditions thereafter. Skies will clear out this evening
through Sunday morning while winds continue to diminish. There
is a decent chance of moisture trapped under the nightly
inversion being manifested as ground fog Sunday morning so have
included mention of it in this TAF.

/OUTLOOK FOR KMSP/
MON...VFR. MVFR/-TSRA likely late. Wind SE 20G35 kts.
TUE...VFR. Chance MVFR/-TSRA. Wind SW 15G25 kts.
WED...VFR. Chance MVFR/-RA. Wind 10-15kts.

&&

.HYDROLOGY...
Issued at 236 PM CDT Thu May 2 2024

The continued wet pattern for the next week will also continue
to cause rising rivers over the entire HSA. Soils have started
to become saturated at upper levels, so runoff is increasing
with each rain event, though the onset of the growing season
does help along with recovery days between rain events. All
told, most tributaries and mainstem rivers will continue a slow
rise for at least the next week, with some in the Minnesota and
Crow river basins approaching minor flood stage by early next
week (Minnesota at Morton already there).

&&

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

&&

$$

DISCUSSION...
AVIATION...JPC
HYDROLOGY...CCS