665
FXUS63 KMPX 211827
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
127 PM CDT Sat Sep 21 2024

.KEY MESSAGES...

- Isolated to scattered showers and storms in central Minnesota
  this morning shifting to southern Minnesota into western
  Wisconsin later today.

- A fall temperature roller coaster with another warm day today
  before temperatures fall substantially Sunday and warming back
  up through the rest of the week.

&&

.DISCUSSION...
Issued at 240 AM CDT Sat Sep 21 2024

This weekend...Scattered showers with some isolated
thunderstorms will continue this morning driven by a LLJ in the
warm sector of the advancing system. Another round of showers
and thunderstorms is expected today along and ahead of the cold
front. With a cap in place there should be a time gap in
precipitation later this morning once the LLJ driven convection
comes to an end. As the surface heating continues ahead of the
front thermal profiles will eventually allow for the cap to
break. This will most likely be in the afternoon. By that time
the front should get far enough that the most likely areas for
rain and thunder will be in the southeastern quarter of
Minnesota and into western Wisconsin. The heating under the cap
should allow for some instability to form with up to around 1000
J/kg of SBCAPE forecast. Not a great shear setup so the chances
for severe storms are low. Any chance for a stronger storm
would likely be pulse convection and would not be a long lived
strong to severe threat if even occurs. Temperatures will be
much cooler behind this front with temperatures across
northwestern Minnesota (behind the front) 20 to 25 degrees
cooler than southeastern Minnesota (ahead of the front) for
today`s forecast high temperatures. Behind this front Sunday
will be much cooler with high temperatures in the mid to upper
60s. Also with high pressure moving in, there should be
clearing skies during the day. Another system likely staying to
our south is unlikely to provide rain chances, but could keep
cloud cover longer across southern Minnesota into parts of
western Wisconsin.

Monday through Friday... The week ahead will be dominated by
surface high pressure with little chance for additional
rainfall. Also under mostly high pressure expect clear to mostly
clear skies. Winds at 850 mb trend back to a southerly or
westerly direction with more of a WAA regime in place. This will
help provide a warming trend through the week. Bringing
Monday`s highs of near 70 up into the upper 70s by the end of
the week. Normal high temperatures this time of year are in the
upper 60s. So near normal the start of the week warming back
above normal for the remainder of the week. Despite annual
precipitation numbers still well above normal September has
been dry for many, with MSP Airport currently on track for one
of the driest Septembers on record.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 111 PM CDT Sat Sep 21 2024

First round of storms is winding down, but a field of accas that
extends back into southeast SoDak indicates that the atmosphere
isn`t done with thunderstorms yet. There is a cold front from
STC down through MKT at 18z, with upwards of 2000 j/kg of
muCAPE present out ahead of it, with it certainly possible that
as that accas moves over the tongue of instability, it will pop
off more storms, hence why we left prob30s in place at
MSP/RNH/EAU for later this afternoon. Behind the front, we will
see gusty northwest winds deep into the evening, with gusty
winds coming back Sunday morning across western WI in
particular, where the pressure gradient will be the strongest.

KMSP...Given the accas field to the west, left the prob30 going
for the potential for on more round of storms to develop before
we completely loose the instability. Also, with the front moving
through this afternoon. A wind shift requiring a shift over to
north flow operations will be needed around 22z.

/OUTLOOK FOR KMSP/
MON-WED...VFR. Wind SE 5-10 kts.

&&

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

&&

$$

DISCUSSION...NDC
AVIATION...MPG