653
FXUS63 KMPX 150209
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
909 PM CDT Wed Aug 14 2024

.KEY MESSAGES...

- Rain increases in coverage this evening, with the bulk of
accumulation falling from 7pm tonight through 7am tomorrow. Isolated
thunder possible, but storms not expected.

- Wrap around showers continue through Friday with dry weather
returning this weekend.

&&

.UPDATE...
Issued at 909 PM CDT Wed Aug 14 2024

Thunderstorm activity to our south has inhibited the expected
spread of showers across Minnesota from the low level jet. A
line of thunderstorms continues to track across South Dakota.
With the environment in Minnesota largely undisturbed this
evening this line should continue across Minnesota. Rain amounts
will be lower than previously forecast, but rain is still
expected as this line of storms moves into Minnesota. Limited
instability will lessen the chances for thunderstorms as the
line moves into Minnesota. Ample moisture with above normal
precipitable water though should still allow for a period of
moderate to heavy rain. The question remains for in coverage
with how much of the area will see this rain as it tracks across
the Upper Midwest. A spread remains in CAMs at this moment.

&&

.DISCUSSION...
Issued at 237 PM CDT Wed Aug 14 2024

Showers have been slow to develop today which coincides with what
CAMs were saying yesterday, as opposed to the much more aggressive
and widespread global models. The culprit is relatively weak forcing
as until now there has been limited shortwave energy within the
upper level wave developing the surface low over us, which has kept
widespread rain development out of the MPX area and confined to Iowa
and the Dakotas. This is expected to remain the case over the next
few hours as we await the nocturnal strengthening of the low level
jet to bolster the forcing and produce more widespread showers
across the area, which looks to arrive after 6-7pm this evening.
Forecast soundings continue to point towards little to no
instability potential, thus we are not expecting thunderstorms other
than the odd rumble of thunder in primarily southern Minnesota as
the jet strengthens this evening. The bulk of the precipitation is
expected to fall between 7pm to 7am while the jet is strongest, with
moisture rich air advecting northwards alongside the low level
convergence characteristic of a low level jet. The expected rain
amounts have decreased on the high end, with the expected range
being 1/2 to 1 inch give or take a 1/4 inch or so depending on where
some heavier showers set up overnight.

Continued showers are expected on and off throughout Thursday as the
upper level low occludes with the surface low spinning over the
northern half of the state, with the MPX coverage area with an area
of cold air advection aloft on top of relatively warm lower levels.
Additional accumulations will only range from a tenth to a quarter
inch through Thursday with additional hundredths from more isolated
cold air showers on Friday.

As the upper level low moves eastwards by mid to late Friday,
showers will exit with it as a broad upper level ridge builds over
the western CONUS with northwesterly flow alongside general
subsidence. Shower chances appear scarce in this setup although we
could get a few showers next week with potential shortwave energy
drifting through the area on the eastern side of the ridge.
Otherwise, expect similar temperatures to the previous couple of
weeks with mostly upper 70s to low 80s for highs and diurnal cumulus
being the majority of the cloud cover.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 626 PM CDT Wed Aug 14 2024

Ceilings will gradually lower this evening as the rain
approaches, first into MVFR and then as the main round of rain
arrives IFR. IFR ceilings will stick around for a while on
Thursday after the rain comes to an end before lifting over the
course of the afternoon and evening. VFR should return by
Thursday night. Winds will remain gusty this evening into early
tonight. Gusty winds will decrease overnight into Thursday
morning. Isolated thunderstorms are possible, but not likely
enough for inclusion in the TAFs. If they were to occur it would
be on Thursday morning.

KMSP... Continued gusty winds this evening with a chance for
some showers, but continued VFR. Tonight MVFR is expected with
showers moving through. The main round of rain is expected on
Thursday morning when IFR is expected. After the rain comes to
an end, ceilings will rise back to VFR by the evening.

/OUTLOOK FOR KMSP/
FRI...VFR, chc MVFR/-SHRA. Wind NW 10-15 kts.
SAT...VFR. Wind NW 5-10 kts.
SUN...VFR. Wind W 5-10 kts.

&&

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

&&

$$

UPDATE...NDC
DISCUSSION...TDH
AVIATION...NDC