496
FXUS63 KMPX 181730
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1230 PM CDT Tue Jun 18 2024

.KEY MESSAGES...

- Additional thunderstorms likely this afternoon and evening,
  some of which could be strong to severe with additional heavy
  rainfall.

- Locally heavy rain is still possible later today into tonight,
  however flash flooding is no longer expected to pose a
  widespread threat, prompting a cancellation of the Flood
  Watch.

- A brief break in the rain tomorrow should make for a nice day,
  before additional precip chances return Thursday through
  Saturday.

&&

.DISCUSSION...
Issued at 343 AM CDT Tue Jun 18 2024

Yesterday evening/night`s storms have progressed north of our area
this morning, allowing skies to begin clearing out. Increasing S/SE
low-level flow behind the northward advancing frontal boundary will
allow temperatures to rise into the low-mid 80s across much of the
area. Dewpoint temperatures in the low 70s will certainly make
things fell muggy again today, with heat indices potentially
creeping above the 90 mark. This will also depend on our cloud
cover, which the latest hi-res models suggest will fill back in
shortly after sunrise. Airmass destabilization will be the big
thing to watch today as we prep for another round of storms
along a passing cold front from the west.

A moderate to strongly unstable airmass with SBCAPE values of
2500+ J/kg would provide enough buoyancy for some robust
updrafts to form within an area of adequate deep-layer shear.
The primary threats will be damaging wind gusts and isolated
large hail along and ahead of the leading edge of the front
during the afternoon/evening when instability is maximized. As
previously noted, the relatively high low-level wind shear
warrants the need to watch for potential bowing structures as
the line comes together. Given its progressive nature, QPF
totals associated with the system look to most likely range from
0.5-1" with more localized amounts up to 2" possible. While
locally heavy rain is still possible through tonight, there is a
decreasing risk for widespread flash flooding potential,
prompting the cancellation of the Flood Watch for our central
Minnesota and western Wisconsin counties. Temperatures / dew
points will drop off pretty quickly behind the front, which
should feel nice after a muggy day!

Tomorrow should be nice day with highs generally in the
mid-70s, partly sunny skies, and relatively weak winds. Any
precipitation should stay southeast of our area as well, which
will allow for a nice break before rain chances return again on
Thursday. Southwest flow aloft will aid several more chances for
precip from Thursday through Saturday, with an additional 1-2"
of rain likely for most locations, and 4"+ still possible where
the strongest storms move through. Thus, continued surveillance
of rivers and streams for potential flooding concerns will be
needed through the end of the week.

A final kick from a h500 shortwave on Saturday should give way
to a more settled pattern at the start of next week, providing,
at the very least, a brief break in the active weather.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1221 PM CDT Tue Jun 18 2024

Biggest change for this TAF set was to lower cigs after the
FROPA this evening and keep them MVFR/IFR through much of the
overnight. Did not mess with the timing of -TSRA much as it
still looks to be on track. Winds will become southwesterly to
northwesterly as the front passes. Most sites will hold on to
MVFR/low end VFR through the end of the period.

KMSP...Based on hi-res models, added in some VCSH through early
this afternoon. There looks to be some isolated convection ahead
of the main line, which is still forecast to impact KMSP
beginning around 23z. Cigs drop as mentioned above and have
decided to keep them MVFR through tomorrow morning.
Southwesterly winds with gusts of 30-35kts will be possible from
around 23z through 03z.

/OUTLOOK FOR KMSP/
THU...VFR/MVFR, chc -TSRA/-SHRA. Wind E 5-10kts.
FRI...VFR/MVFR, chc -TSRA/-SHRA. Wind S 10-15kts.
SAT...VFR/MVFR, chc -TSRA/-SHRA. Wind SW 10-15kts.

&&

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

&&

$$

DISCUSSION...BED
AVIATION...Dye