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fxus63 kmpx 221718 
afdmpx

Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
1218 PM CDT sun Sep 22 2019

Update...
issued at 1215 PM CDT sun Sep 22 2019

Updated for 18z aviation discussion below.

&&

Short term...(today through monday)
issued at 455 am CDT sun Sep 22 2019

Precipitation has remained south and east of the County Warning Area overnight, as
the front responsible for saturday's thunderstorms continues to
slowly move off tot he east. Cooler and drier air continues to
filter into the region behind the cold front, with temperatures
across western Minnesota already dropping into the low 50s. This
cooler air will continue to advect into the region today, which
along with widespread cloud cover spreading across the area during
the day, will limit highs to the mid to upper 60s. A few showers
will also be possible today from southern Minnesota through west-
central Wisconsin, as forcing aloft from an upper level low passes
overhead. Forecast soundings show plenty of dry air to overcome
below 700 mb this morning, so expect most activity to hold off until
mid-late afternoon. Precipitation amounts look to remain around a
tenth of an inch or less. This activity could continue late into
tonight across west-central Wisconsin before the forcing aloft moves
off to the east.

A drier day is expected Monday as ridging builds into the upper
Midwest, and high pressure to the south keeps the dry air in place.
We'll see our first fall-like morning in a while as clearing skies
and the much more seasonable dew points in place allow temperatures
to drop into the upper 40s to low 50s. Plenty of sunshine on Monday
will allow for highs to reach the 70s across most areas.

Long term...(monday night through saturday)
issued at 455 am CDT sun Sep 22 2019

There are two main concerns in the long term. One would be the short
wave coming in later Tuesday with severe potential and the other is
the deep trough becoming established in the west with a lead short
wave and heavy rain threat Friday into Friday night.

The deterministic models and most gefs/European model (ecmwf) ensemble members are in
pretty good agreement with the incoming short wave from the WNW on
Tuesday. It looks to be strengthening as it moves into the upper
Midwest. One main question will be the amount of moisture that is
able to return. Deep layer moisture gets shunted south to Oklahoma
in the wake of todays front and upper ridge. As the wave approaches
Tuesday, 850mb winds will increase to 20-30 knots during the day,
and even stronger Tuesday evening. Shear will be significant and
there probably will be some decent moisture return, so severe
weather does look possible later Tuesday.

Following the short wave, cooler air invades the area Wednesday,
possibly continuing through the end of the week. Models diverge only
a bit for the latter portion of the week, and the general theme is
definitely a deep trough along the West Coast and prolonged upper
southwest flow over this area Friday through Sunday and beyond.
Timing differences exist, but it appears there will be an embedded
short wave Friday and Friday night. Precipitable water values look
to be around 1.4 inches or so through Friday night and heavy rain is
certainly a concern. Precip probabilities will decrease some on
Saturday and Sunday, as the surge of moisture exits the area with
the departing wave, and it also appears that the broad high pressure
in the southeast may expand into our area somewhat. But will need to
keep a small chance of rain through the weekend with the southwest
flow and likely lingering instability and potential for diurnal
showers and storms.

&&

Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 1215 PM CDT sun Sep 22 2019

Some patchy MVFR cigs developed under weak ridging this morning.
We should break free of that early over the east and southern
areas. VFR trend expected then with a chance of -shra over the
southeast third of the area, mainly east and south of kmsp.
Surface winds northwest-west this afternoon becoming west-SW into Monday,
generally 10kts of less.

Kmsp...mentioned vcsh for the afternoon, but believe anything
significant will remain well southeast of the terminal.

/Outlook for kmsp/
Mon night...VFR. Wind light and variable.
Tue...chance evening MVFR/tsra. Wind SW 5-10 kts.
Wed...chance morning MVFR/tsra. Wind west 10-15 kts. Gusts 25-30
kts.

&&

Mpx watches/warnings/advisories...
WI...none.
Minnesota...none.
&&

$$

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