NWS Forecast Discussion

Below is the latest Area Forecast Discussion from the Twin Cities National Weather Service office in Chanhassen, MN. It gives insight into why the forecasters are making the predictions you read in your local forecast. The overall "big picture" of the atmospheric setup is well described, as well as the forecasters' interpretation of the various Computer Atmospheric Models (CAMs). Sometimes, very specific information is available here that is not available, or otherwise generalized, in the public forecast.

671
FXUS63 KMPX 181905
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
205 PM CDT Sun May 18 2025

.KEY MESSAGES...

- Patchy of frost possible in far eastern MN and west-central WI
  tonight into Monday morning

- Soaking rain arrives Monday into Tuesday, with highest chances
  in western MN and along I-90, lowest chances north of I-94.
  Severe weather is not expected.

- Drier and warmer for the second half of the week.

&&

.DISCUSSION...
Issued at 156 PM CDT Sun May 18 2025

TODAY AND TONIGHT, early afternoon satellite imagery and surface
ob showed clearing skies across the region with upper level
subsidence leading to surface high pressure. Overnight, these
clearing skies and light winds should set the stage for patchy
frost across far eastern Minnesota and western Wisconsin. Have
opted to hold off on any Frost/Freeze headlines given the
uncertainty in the sky cover as seen from last night, and
temperatures borderline in the low 30s.

MONDAY THROUGH SATURDAY...Confidence as increased in widespread
rain slowly moving eastward tomorrow, but then settling across
the region south of I-94 on Tuesday, before slowly exiting on
Wednesday. There will be some MUCAPE at the onset on Monday, so
could hear some rumbles of thunder, but the CAPE is low, and so
too is the threat for severe weather. On Tuesday, large scale
forcing for ascent will be the driver in the precipitation
despite any instability. As a result, expect widespread,
stratiform rain. The ECMWF continues to be the most aggressive
on rainfall totals, while the GEFS and CFS are drier.

One thing that is for sure is folks under the heaviest rain
should get close to 2 inches or higher, and also there will be a
sharp gradient where rainfall amounts will quickly taper off to
near nothing. Right now this gradient appears to be along I-94,
but that could shift. Since this will be a stratiform rain, the
risk for flooding is low since rainfall rates will be on the
order of a quarter of an inch per hour. The threat for severe
weather will be near zero.

Looking ahead, this system will exit on Wednesday, and high
pressure will build in for Thursday. Temperatures will gradually
warm and more sunshine is expected for the end of the week.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1258 PM CDT Sun May 18 2025

Aviation...A few sites have been lucky to break into clear skies
this afternoon otherwise scattered low VFR cigs prevail.
Northwesterly winds around 10kts will shift gradually to the
northeast over the next few hours and eventually east by tomorrow
morning. Mid-level clouds are expected to mix in as the night
progresses as our next system approaches from the west. Wind gusts
are expected to increase between 20-30kts for AXN and RWF tonight
and remaining sites near 12z. Rain showers are possible especially
for RWF and MKT between 11-14z. Widespread precipitation looks to
hold off until next period.

KMSP...Winds will continue to shift NE becoming a crosswind to
12/30s after 22z and then becoming easterly around 6z. BKN to OVC
mid-level cigs begin to mix in overnight with increasing wind gusts
tomorrow morning as a system approaches from the west. Best shot of
precip looks to reach MSP during the next period but did introduce a
prob30 for the chance of few convective showers late afternoon.

/OUTLOOK FOR KMSP/
TUE...MVFR/SHRA likely, chc -TSRA/IFR. Wind NE 15-20G30kts.
WED...MVFR/-SHRA early, then VFR. Wind NE 5-10kts.
THU...VFR. Wind NW 5-10kts.

&&

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

&&

$$

DISCUSSION...JRB
AVIATION...Dunleavy

NWS MPX Office Area Forecast Discussion