893
FXUS63 KMPX 272023
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
323 PM CDT TUE SEP 27 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 321 PM CDT Tue Sep 27 2016

An area of stratiform rain will move across eastern MN and western
WI this afternoon and evening. Rainfall totals will generally be
less than a tenth. The rain is driven by a enhanced area of PV along
a shortwave trough rotating around a cut off upper level low. This
PV anomaly will rotate southeast, and the rain will gradually end
from north to south as it does so.

By Wednesday morning expect lingering clouds and northerly winds.
Forecast soundings show the clouds will be slow to dissipate in
central/eastern MN and western WI. Meanwhile western MN will have
clear skies. The breezy northwest winds will gradually become
northerly, and eventually northeasterly on Wednesday.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 321 PM CDT Tue Sep 27 2016

We are still anticipating nearly perfect fall weather through
Monday, with only one small tweak to the forecast for Saturday with
the next front of significance and chance for rain arriving Monday
of next week.

Main player for the weather through the weekend will be the upper
low currently over Lake Superior. This low will be cut off from the
main westerlies and drift down into eastern Kentucky/Tennessee by
Friday morning, at which point the GFS/ECMWF show this upper low
retracing its foot steps, ending up back over Michigan on Saturday.
Being northwest of the low, we will see pleasant and dry conditions
under the influence of high pressure Thursday and Friday, but as the
upper low moves into Michigan, it`s cyclonic flow and associated
cloud cover will start backing into our eastern areas. We have seen
the GFS trend west with the low, toward the ECMWF over the past
couple of runs, which has a couple of implications for the forecast.
One, increased cloud cover now shows up on Saturday as far west as
the Twin Cities, while a chance for showers has been brought into
western WI.

For next week, we are still seeing timing differences for when an
upper trough building over the Rockies this weekend begins moving
out into the Plains. The GFS continues to be the most progressive
with it, bringing this system in Monday night, with the ECMWF 12-18
hours behind. Given the strength of the upper ridge this weekend
over eastern Canada, the slower progression is likely the way to go.
As a result, we removed Pops from the forecast for Sunday night and
delayed how quickly they push east Monday into Monday night.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 151 PM CDT Tue Sep 27 2016

VFR conditions will give way to MVFR and possible IFR at the
Wisconsin sites as an upper level low rotates over the Great Lakes
and brings low clouds and showers across the Upper Midwest.
Northwest winds will gradually become northerly overnight with a
slight easterly component expected on Wednesday morning.

KMSP...
Rain showers are located just to the northeast of KMSP, but should
impact KMSP later this afternoon. Visbys should stay above 6
miles. The main concern is the low clouds which are forecast to
dip below 3000 ft, but they should remain above 1800 ft tonight.
VFR conditions will return Wednesday morning.

/OUTLOOK FOR KMSP/
Thu...VFR. Wind NE at 10kt
Fri...VFR. Wind NE at 05kt
Sat...VFR. Wind NE at 05kt.


&&

.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&

$$

SHORT TERM...JRB
LONG TERM...MPG
AVIATION...JRB