NWS Forecast Discussion

000
FXUS63 KMPX 260500
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1100 PM CST Thu Feb 25 2021

.UPDATE...For 06Z Aviation discussion below

&&

.SHORT TERM...(This evening through Friday night)
Issued at 255 PM CST Thu Feb 25 2021

Clouds have only finally dissipated across southeastern MN this
afternoon. The rest of the region has been full of sun and
temperatures are slowly rising toward forecast highs due to the
relatively light flow. In snow-free areas of west central MN and
SD, mixing has been more efficient and temps have been allowed to
rise into the mid to upper 40s. In the snowpack areas, temps have
been held back to the mid and upper 30s due to albedo effects and
limited surface heating/mixing.

Temperatures tonight and Friday will be more uniform across the area
as strong southerly flow develops late tonight. As the morning
progresses, mechanical mixing will try to bring dry adiabatic
profiles to the area, despite the snowpack. It may not be fully
realized, however, which keeps some doubt into how high wind gusts
will be. Nevertheless, it appears we`ll see at least 40 mph gusts
from late morning through mid afternoon until the winds aloft weaken
with an approaching low pressure area from the Dakotas. Decided
against a Wind Advisory for now due to the short duration and
marginal gusts, but we cannot rule out 50 mph gusts in some places if
the snow has little impact on the development of dry adiabatic lapse
rates.

The wind will transport some moisture northward, but it continues to
appear any precipitation won`t develop until Friday evening over
WI. It will also be very light with snow accumulations under a half
inch.

.LONG TERM...(Saturday through Thursday)
Issued at 255 PM CST Thu Feb 25 2021

The long term portion of the forecast offers a chance for
precipitation Saturday night and a warming trend through next week
with a couple of brief cool downs mixed in.

Clouds will be on the increase on Saturday ahead of the next system.
Highs will be in the 30s and 40s. Saturday night a low pressure
system tracks south of the CWA through Iowa and southern Wisconsin.
There looks to be a little more moisture with this system, and there
are some hints that it may try to pull in some gulf moisture, so at
this time it looks like an inch or two of snow is possible with the
best chances in the southern and eastern parts of the forecast area.
There is a chance for some mixed precipitation at the onset, but any
precipitation should quickly turn to snow as the column cools. The
deterministic models have been wavering on the strength and spatial
extent of this system so it will continue to be monitored closely for
any changes. Any snow will exit the area early Sunday. High
temperatures on Sunday behind the cold front will get knocked back
into the 20s and 30s.

Beyond Sunday the rest of the period looks benign with seesawing
temperatures. Surface high pressure will begin to move off to our
east on Monday and the winds will go around to the south bringing in
warmer air and boosting highs back into the 30s, except 40s in west
central Minnesota where there is little snowpack. A low pressure
system moving north of the border will bring a warm front across the
CWA on Tuesday and high temperatures will warm several more degrees
into the upper 30s and low 40s east with 50s possible west. A cold
front will knock the highs on Wednesday back into the 30s, before we
warm back up again going into the end of the week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1100 PM CST Thu Feb 25 2021

Winds are the primary concern this TAF period. An increasing low-
level jet brings low-level wind shear overnight, with increasing
surface gusts on Friday as winds mix down to the surface. Sustained
20-25 knot winds with 35-40 knot gusts look to be common on Friday
afternoon. Mid/High clouds increase throughout the period, with
rain/snow possible toward the end of the period at eastern sites
(mainly KEAU).

KMSP...Low-level wind shear looks to develop overnight, then
transition to increasing surface gusts (to 35 knots) by late Friday
morning. VFR is expected through the period as far as
ceilings/visibility are concerned.

/OUTLOOK FOR KMSP/
Sat...Chc MVFR cigs with -SN possible late. Wind NW 5-15 kts.
Sun...MVFR/-SN possible early, then VFR. Wind WNW 10-15 kts.
Mon...VFR. Wind N at 5-10 kts.&&

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

$$


SHORT TERM...Borghoff
LONG TERM...CEO
AVIATION...LS

NWS MPX Office Area Forecast Discussion

Script by Ken True @Saratoga-Weather.org