Bloomington, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

704
FXUS63 KMPX 161944
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
244 PM CDT Wed Apr 16 2025

.KEY MESSAGES...

- Elevated fire weather conditions this afternoon due to low
relative humidity and breezy winds. The two areas of most concern
are southwestern MN and east-central MN to northern WI.

- Strong to severe thunderstorms are possible beginning Thursday
afternoon through early Friday. Large hail is the primary threat.

- An active pattern persists through the middle of next week,
  with a larger system possible Sunday into Monday.

&&

.DISCUSSION...
Issued at 244 PM CDT Wed Apr 16 2025

The immediate concern this afternoon remains elevated to near-
critical fire weather conditions for portions of southwestern
Minnesota as well as east-central Minnesota to northern Wisconsin.
Surface observations show temperatures in the low to mid 60s with
winds out of the southeast at 15-20 gusting to 30mph in southwestern
Minnesota and weaker winds with temperatures in the 50s elsewhere.
The window for near-critical fire weather conditions has remained
quite small with the peak over the next 3 hours before conditions
begin to improve as we slowly lose daylight, resulting in weaker
mixing and therefore slower winds and cooling temperatures. GOES 19
satellite imagery shows a band of thicker clouds along and north of
I-94 moving eastwards with thinner clouds along the Minnesota River
which will further point towards southwestern Minnesota being at
greatest risk for fire weather conditions. Skies will remain partly
cloudy tonight as our next chance for showers and thunderstorms
arrives on Thursday as a surge of low to mid level warm air
advection will produce spotty showers as early as mid morning, ahead
of the primary forcing which will arrive as a low level jet
strengthens later in the evening coinciding with the arrival of a
mid level shortwave. Longer range CAM guidance that has resolved the
entire event shows a swath of early convection moving from southwest
Minnesota towards the Twin Cities metro and into northern Wisconsin
ahead of a secondary round that looks to be stronger during the
evening and overnight. Going through the suite of forecast soundings
from both the global and CAM guidance, our CAPE profile is deep but
not wide such that our peak updraft intensity will end up on the
lower end of the spectrum despite 1500-2000 J/KG such that we will
have an upper limit to just how strong storms will end up. Other key
factors include weak to mediocre shear at best, strongest during the
evening as the low level jet and mid level shortwave combine to
produce a triple-point feature over southern Minnesota and northern
Iowa. Lapse rates look to remain on the high end such that large
hail will remain the primary risk with severe thunderstorms, with
strong winds being a secondary weaker threat. LCLs should range from
3-4kft such that tornadoes are not favored at this time, especially
given the poor low level shear compared to the better environment in
the mid levels. All things put together, our best chance for severe
weather will likely be elevated hail producing storms during the
evening favoring southern Minnesota and northern Iowa progressing
eastwards as the low level jet migrates towards lower Lake Michigan
overnight into early Friday. There should be enough forcing north of
the better environment to produce scattered to widespread showers
such that most of the region will see at least some amount of rain
from the event with lower amounts in west-central Minnesota. WPC QPF
shows a peak QPF from the convective bands in the 1.5-2 inch range
compared to 3-4 inches in the HREF LPMM QPF, however the HREF
solution is likely too hot and would rely on multiple rounds of
convection moving over the same area.

As we move beyond and into the weekend, showers will end early on
Friday with mostly cloudy skies lingering throughout the day as we
do not see enough subsidence to erode the cloud cover until
Saturday. Quick moving high pressure will result in mostly clear
skies and cooler temperatures on Saturday before clouds return
gradually Sunday ahead of our next system. The suite of global
guidance all show a system moving through the region late Sunday
into Monday with a large degree of variance in solutions among
ensemble members. The deterministic GEM/ECMWF both show a well
developed surface low and upper level trough swinging across the
region from south-western Iowa to southeast Minnesota, which would
place our area on the northwest cooler side and result in widespread
rain showers but little to no chance for severe weather. The 12z GFS
shows a much farther east trajectory and weaker surface based system
such that we would end up almost completely dry for the same time
period. GEFS/EPS/CFS guidance all show varying degrees within the
ensembles, with generally 50-60% of membership showing meaningful
precipitation falling at MSP and the rest favoring a drier solution.
The most likely area to see precipitation will be southeastern
Minnesota and western Wisconsin with lower chances to the northwest
farther away from the system. One question is also if we manage to
squeeze flurries or light snow out of the far northwestern edge as
some members do have a few tenths of accumulation in the Alexandria
area, however this is a low probability solution as less than 5% of
members show anything but rain within the greater ensembles. Suffice
to say, the Sunday to Monday system is by no means a high confidence
forecast and will be something to monitor closely as we head towards
the weekend, with the hope being ensemble guidance comes into better
agreement with more membership showing either a dry or wet solution.
The active pattern continues into the middle of next week as
persistent 20 to 40 percent chance for showers persists through the
end of the period with zonal flow aloft and potential for weak
shortwaves as well as no strong surface systems.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1245 PM CDT Wed Apr 16 2025

Not much happening this period until Thursday morning. One trend
we`ve seen with the 12z models is a lack of activity within the
warm advection Thursday morning, with most models holding off on
storms until the afternoon along the cold front. The one
exception is up in central MN, where several CAMs show activity
developing during the late morning hours. Otherwise, fairly
widespread convection is expected Thursday afternoon across
central and eastern MN ahead of the cold front that will be
moving across western MN during peak heating on Thursday. Given
the timing, only the end of the 30 hour TAF period at MSP has a
TS threat worthy of mentioning this period. For CIGS, went the
route of the RAP, which shows low cigs likely holding off until
after the fropa, so no widespread warm sector IFR/MVFR cigs like
we`re seeing with the LAV, with all TAFs remaining VFR this
period, though this is something we`ll continue to reassess
through the night.

KMSP...HREF shows TS probabilities of over 80% at MSP Thursday
afternoon, so jumped out beyond a prob30 for that threat with
the prevailing shra & tempo TS Thursday afternoon. It`s thunder,
so there`s still plenty of time for the placement of TS to
change, though the 12z HREF would say it could be a very active
afternoon on Thursday, with upwards of 2" of rain possible.

/OUTLOOK FOR KMSP/
FRI...MVFR/-SHRA early, then VFR. Wind NW 10-15 kts.
SAT...VFR. Wind NW 10-15 kts.
SUN...Chc MVFR/-SHRA. Wind E 10-15 kts.

&&

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

&&

$$

DISCUSSION...TDH
AVIATION...MPG