FXUS63 KMPX 181044

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
544 AM CDT Thu Apr 18 2019

.SHORT TERM...(Today through Friday)
Issued at 411 AM CDT Thu Apr 18 2019

The surface low that moved through yesterday has reached northern
Michigan, but the main upper level trough axis lags well to the
west. Early morning analysis and satellite imagery shows the upper
trough axis entering western MN and the trough itself has become
more amplified overnight. This will be the main driver of the
weather today. With the upper trough expected to push through from
west to east during the day, a large cloud shield with isolated
to scattered showers can be expected. Showers will likely peak
this afternoon in intensity and coverage across eastern MN and
western WI given the cold core aloft aligns over that area during
peak surface heating, implying the best lapse rates for shower
development. Do not expect thunder at this time as the steep lapse
rates will be quite shallow. These showers will bring nothing
more than a short-lived burst of moderate rainfall. Winds at the
surface will increase to 15 to 20 MPH with gusts of 25MPH from the
northwest today. Showers could lead to even stronger gusts given
shallow inverted-V soundings.

Anti-cyclonic flow quickly builds in from the west this evening.
Diurnally driven showers will quickly dissipate and cloud cover
should follow suit. A surface ridge axis will build in from the west
and stay in place all night and through Friday. Friday will start
cool, but will end up being a pleasant day overall with sunny skies
and highs in the low 60s.

.LONG TERM...(Friday night through Wednesday)
Issued at 411 AM CDT Thu Apr 18 2019

Not much expected weather-wise during the long term with the main
forecast concerns being how warm do we get Saturday ahead of a cold
front and then what are the chances we get rain behind the cold
front Sunday.

Models continue to point to a thermal ridge moving over MN right
during peak heating Saturday afternoon. 925mb temps ranging from 16c
in northwest WI to 22c in southwest MN will support widespread highs
in the 70s, with some near 80 degree temperatures not out of the
question out in western/sw MN. Given this thermal ridge
axis, did push forecast highs on Saturday out toward the 90th
percentile from the model certainty tool.

This front will be approaching the Alexandria area late Saturday
afternoon and will clear Albert Lea/Eau Claire early Sunday morning.
Ahead of the front, the atmosphere is very dry and capped as well,
so no pre-frontal precip is expected. Post frontal is a different
story as a band of mid-level fgen moves in. The big question is the
extent of dry air in the low levels.  GFS forecast soundings show us
being pretty dry below 10k feet Sunday, keeping Sunday cloudy, but
mostly dry. The ECMWF has been bouncing back and forth between a dry
and rainy post frontal environment and with it`s 18.00 it bounced
back into the rainier category. Majority of guidance and GEFs
members are dry behind this, so forecast is dry like we have been
going with, but it`s not a done deal yet that Sunday will be dry.

Next week models continue to show split flow dominating, with the
main northern stream up in Canada, with another diffuse trough
working across the Plains Tuesday/Wednesday. Through Wednesday
though, we will be under the influence of a surface ridge axis
that will be associated with a parent high moving across the Hudson
Bay region. This will keep us mainly dry with temperatures near
normal. We start getting more return flow Thursday, with a more
sizable warm-up looking likely for the end of next work week.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 540 AM CDT Thu Apr 18 2019

The main upper level trough is overhead early this morning and
will work through the area during the day. MVFR cigs should be
fairly widespread except western MN where there have been several
sites reporting VFR conditions early this morning. Breezy
northwest winds will increase during the day, with gusts over 20
knots by this afternoon. Scattered showers are anticipated as
well, peaking during the afternoon hours. Skies will clear tonight
and winds will lose their gusts during the late evening hours,
especially across the east.

KMSP...MVFR cigs with scattered showers and breezy northwest winds

Fri...VFR. Wind light/variable.
Sat...VFR. Wind S 10G20-30 kts.
Sun...VFR. Chc -SHRA/TSRA. Wind NW 10-15 kts.





NWS MPX Office Area Forecast Discussion