Area Forecast Discussion
Issued by NWS Twin Cities, MN
FXUS63 KMPX 241919
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
219 PM CDT MON OCT 24 2016
.SHORT TERM...(Today and tonight)
Issued at 300 AM CDT Mon Oct 24 2016
The surface ridge of high pressure that settled into the area
overnight will bring a dry and mild day with light winds and mostly
sunny skies. With little in the way of mixing, temperatures will max
out right around seasonal normals, with readings in the low to mid
50s this afternoon.
This evening clouds will be on the increase as the aforementioned
high slides off to the east and isentropic lift ensues ahead of the
approaching wave. There could be a few showers developing between
09z and 12z Tuesday, although the majority of the precipitation
should hold off until after daybreak.
.LONG TERM...(Tuesday through Sunday)
Issued at 315 AM CDT Mon Oct 24 2016
Confidence remains high for widespread precipitation to develop
Tuesday, and continue through Tuesday night, early Wednesday. As
with previous forecast concerns, timing with the onset of
precipitation Tuesday, especially across eastern Minnesota and
western Wisconsin, remains problematic. This is mainly do to
initial dry air mass across the Great Lakes advecting drier air
westward across the our region Tuesday. Overall, models have
depicted heavy QPF amounts with the system, but have tapered off
across central Minnesota over the past several runs. This decrease
or tapering off of the heavier QPF amounts is related to a slight
shift southward of the surface low across Iowa. There is no
question that all of MPX forecast area will get wet, the main
question is where the heaviest QPF amounts develop. The best time
frame for heavy rainfall will occur Tuesday evening as the best
lift and moisture advection resides across southern Minnesota.
This axis of heavier rainfall will shift to the east late Tuesday
night, early Wednesday, with a general tapering off of the light
rainfall Wednesday morning from eastern Minnesota, into west
Past Wednesday, model spread increases as the mean upper flow
becomes slightly west-northwest across the Upper Midwest. The
larger spread of the ensembles means that confidence in the
forecast is low.
Overall, the 50H /5-day mean of the GFS, EC, CMC/ model run has
the upper level pattern continuing to depict a long wave trough
over the eastern Pacific and eastern Canada through next weekend.
In between, a weak ridge dominates the southern Plains, and desert
southwest. As mentioned before, the Upper Midwest has a slight
west-northwest flow later this week, and into the weekend. This
type of flow does support weak short waves riding southeast across
the Upper Midwest, and some of the model solutions do support
light precipitation late this week, and next weekend.
Although confidence remains low on temperatures past Wednesday,
based the mean upper pattern and the core of the coldest air
remaining across Canadian, no significant cool down is expected
through the first week of November. Even the CFSv2 /Climate
Forecast System Ensemble/ supports the warmer temperatures across
the Upper Midwest through the first week of November. Beyond the
first week of November, the CFSv2 shows some cooling over the
central part of the U.S. with the core of the warmest air holding
across northern Canadian.
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 200 PM CDT Mon Oct 24 2016
VFR with just a few passing high clouds through the night. Cloud
cover gradually increases through the morning. Winds will be light
and somewhat variable.
Calm before the rain tonight and tomorrow morning. Winds have been
light and somewhat variable between northeast and southeast
today. Gradually the winds are expected to settle in out of the
east southeast. Rain moves in during tomorrow afternoon and will
remain in place until Wednesday once it arrives.
/OUTLOOK FOR KMSP/
Tue Night...Becoming MVFR with -RA. Chc IFR late. Wind SE at
Wed...MVFR/IFR with -RA early. Wind ENE at 10kt.
Thu...VFR. Wind VRB 5kts.