015 
FXUS63 KMPX 272023
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
323 PM CDT Sun Oct 27 2019

.SHORT TERM...(This evening through Monday night)
Issued at 323 PM CDT Sun Oct 27 2019

Regional satellite imagery had shown a large area of cloud cover 
over the Upper Midwest with cool northwest flow at the surface. Some 
of the RGB satellite images indicated some cloud enhancement across 
southern/central Minnesota over the last few hours which led to some 
light rain/sprinkles. These enhancements were related to an increase 
in upper level divergence with a strengthening jet overhead. 
However, mid-level forcing remained weak which will continue to 
weaken over the next several hours. This will decrease any chance of 
precipitation and slowly decrease the cloud cover by morning. 

The main upper jet will continue to strengthen over the next 24-36 
hours and move south. As the upper jet moves south, the best upper 
level forcing will also head south as the next short wave moves out 
of the southern Rockies and into the Midwest by late Monday 
night. Surface dew points will also continue to decrease over the 
next 24 hours as the cool/dry air mass moving through the region 
tonight scours out any boundary layer moisture. These much lower 
dew points and very dry boundary layer, will also suppress any 
precipitation from reaching the ground. However, we did leave low
PoPs in a narrow corridor from Albert Lea northeast to Eau 
Claire, Wisconsin Monday night. This area has the best chance of 
any saturation in the boundary layer and thus, precipitation 
reaching the ground. Forecast soundings are cold enough for any 
precipitation to be in the form of snow.

.LONG TERM...(Tuesday through Sunday)
Issued at 323 PM CDT Sun Oct 27 2019

One thing is for sure, we will be seasonably cold through next 
weekend. As for that potential for snow on Halloween, the 
deterministic models have continued their trend in shifting this 
system to the southeast, with it looking increasingly likely this 
system misses the MPX area to the east as well. This would leave us 
with a basically cool and mainly dry week.

We'll be starting the long term Tuesday with a positively tilted 
trough extending from essentially Hudson Bay back to the four 
corners. We'll be within the trough axis through Thursday, which 
puts us well within the cold air of this trough, which means Tuesday 
through Thursday, we'll see highs basically in the 30s, a good 20 
degrees below normal. From the base of this trough a strong wave 
will come out of Colorado on Thursday and be the impetus for 
cyclogenesis on Thursday well to our south. The deterministic models 
have continued the trend of pushing this system southeast, with the 
surface low going up trough the lower Ohio Valley into the eastern 
Great Lakes. However, Euro ensemble members that feed the NBM are a 
run behind, so we still have a good deal of PoPs in the forecast 
Thursday/Thursday night, but at the moment, this is looking way 
overdone, with the 27.12 GEFS precip probabilities staying east of 
the MPX area.  We'll see what happens with future model updates, but 
at this point, we are trending hard away from having a white 
Halloween.

For the rest of the forecast, we get into "dirty" northwest flow, so 
cool with occasional weak waves that will bring about plenty of 
cloud cover and the occasional chance for light precip through the 
weekend. By next weekend, the GFS shows heights building as the 
western ridge attempts to build east, but the ECMWF keeps us locked 
in cold northwest flow. Looking at the ensemble mean height 
forecasts, the ECMWF looks a bit more likely than the modifying we 
see in the GFS at this point.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1220 PM CDT Sun Oct 27 2019

There is enough moisture in the boundary layer to continue high 
end MVFR, or low end VFR cigs through mid afternoon across MPX 
forecast area. Otherwise, VFR conditions will develop later this 
afternoon as cigs lift, and scatter out during the evening. 
Northwest winds of 10-15 kts will decrease and become 
west/southwest Monday afternoon. 

KMSP...

An hour or two of MVFR cigs are possible this afternoon, but 
confidence is increasing that cigs could lift to VFR in the next 
hour. Northwest winds will become west/southwest overnight.

/OUTLOOK FOR KMSP/

MON Night...VFR. Chc MVFR cigs in -SN late. Wind WSW 5-10 kts. 
TUE...VFR. Wind NW 5-10 kts. 
WED...VFR. Wind NNW 5 kts. 


&&

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

$$

SHORT TERM...JLT
LONG TERM...MPG
AVIATION...JLT