463 
FXUS63 KMPX 020510
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1110 PM CST Tue Mar 1 2022

.UPDATE...
Issued at 1110 PM CST Tue Mar 1 2022

Updated to include 06Z aviation discussion.

&&

.DISCUSSION...(This evening through Tuesday)
Issued at 318 PM CST Tue Mar 1 2022

Key Messages:

- Freezing precipitation development overnight, and early Wednesday.

- A potentially significant storm system Friday night through 
  Saturday night could bring all types of wintry precipitation. Snow 
  and ice accumulations are likely, but confidence in specific 
  details and amounts is low. 

A large area of low stratus and fog was present this afternoon 
across North Dakota. The surface front has moved southward into 
central Iowa with a general weak north/northeast flow at the surface 
across central/southern Mn and adjacent west central Wi. Winds
become more west/northwest at the surface and in the boundary layer 
across the Dakotas overnight. 

First, the area of low stratus/fog should progress east/southeast 
across Mn tonight. Weak lift associated with 850-700MB Fgen boundary 
and increasing mid-level moisture could be ample enough to generate 
light precipitation across mostly the northeastern 1/3 of MPX CWA 
late tonight. The timing of both deeper mid-level moisture and the 
effective lift will occur between midnight and 9 AM. Either way, the 
chances of freezing precipitation will likely be south of I-94 where 
deeper moisture is limited. QPF amounts only support a few hundredths
of an inch of liquid equivalent. So, if any freezing precipitation 
develops it should have minimal impacts. By late morning, any mid-
level moisture will quickly exit the region, so low clouds and 
moisture will remain in the boundary layer until later Wednesday as 
much cooler and drier air advects southward across the Upper Midwest.
Tonight's and Wednesday's temperatures will have limited variation 
due to cloud cover. The front associated with Wednesday system will 
stall south of our CWA. Along this front, a much stronger thermal 
profile will lead to stronger forcing and precipitation along it late
Wednesday night. How far northeast this precipitation band moves 
remains questionable. However, it should be close enough to warrant 
high percentages along the Iowa border. Snow will be the predominate
weather type due to much cooler temperatures expected in the 
moisture column. 

Thursday and Friday - High pressure will drift eastward allowing for 
a quiet period to end the work week. Temperatures will be chilly, in 
the mid to upper 20s on Thursday, but return flow develops and sets 
up WAA on Friday. Friday's high will be near average in the mid-30s 
and will remain dry as a low pressure begins to develop lee of the 
Rockies.

Friday night through Monday - Models remain fairly consistent with 
the weekend storm system. 12Z guidance continues to favor a 
stronger, warmer scenario and continues to trend drier with respect 
to QPF amounts. Still expecting snow and a wintry mix initially late 
Friday night before the low center approaches and brings in milder 
air. A brief period of freezing rain is likely before a changeover 
to all rain occurs on Saturday. It is unknown how long the freezing 
rain will last until we get closer to the event, but sub-freezing 
surfaces may freeze liquid precipitation despite temperatures in the 
33 to 35 degree range Saturday AM. However, persistent warm air 
advection will eventually warm temperatures in to the upper 30s 
Saturday afternoon across southern MN. This will be warm enough to 
stop the influence of sub-freezing surface temperatures and allow 
rain to fall and remain liquid. Another caveat is that the track 
will continue to wobble over the next few days and this forecast 
likely won't be the final result come Sunday morning. However, for a 
large synoptic system, models have been remarkably consistent 
despite the changing of weather types due to minor differences in 
thermal profiles. This remains a highly complex set up that will 
require fine tuning over the next day or two but a significant storm 
will impact the region starting Friday night through Sunday morning 
with all precipitation types possible across much of the MPX CWA.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1110 PM CST Tue Mar 1 2022

Recent model trends have been keeping more dry air in the lower
levels of the atmosphere so chances for precipitation tonight have
gone down. There remains a chance for snow at AXN, STC, MSP, RNH, and
EAU overnight. CIGS will still fall into MVFR tonight as the cloud
deck moves in. Winds will either be calm or light and variable 
overnight before rising to light winds from the north during the day
Wednesday. Tomorrow CIGS will remain MVFR to start the day before 
scattering out to VFR in the afternoon/evening. 

KMSP... Chances for snow have gone down with more dry air present at
lower levels of the atmosphere. Some snow could still fall early
Wednesday morning, but totals would be very light (under 0.5"). CIGS
will fall to MVFR as the cloud deck moves in overnight and scatter out
tomorrow late afternoon/evening. Wind will be light overnight 
rising up to around 10 knots from the north on Wednesday.

/OUTLOOK FOR KMSP/

Thu...VFR. Wind E/NE 5-10 kts. 
Fri...MVFR/IFR and a wintry mix likely late. Wind E 10-20 kts. 
Sat...MVFR/IFR. Wintry mix bcmg rain during daylight hours. Wind E
10-20 kts.

&&

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

$$

UPDATE...NDC
DISCUSSION...BPH/JLT
AVIATION...NDC