273
FXUS63 KMPX 100804
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
304 AM CDT Fri May 10 2024

.KEY MESSAGES...

- Chance for frost/freeze in western WI this morning.

- Scattered showers and thunderstorms Friday afternoon, best chance
eastern MN to western WI.

- Chance to see the northern lights tonight, mostly clear skies
 expected.

- Temperatures in the 70s through the period with a chance at 80 on
Sunday.

&&

.DISCUSSION...
Issued at 300 AM CDT Fri May 10 2024

Mostly clear skies are evident on Nighttime Microphysics satellite
imagery this morning with a few areas of fog developing over south-
central Minnesota. Fog is not expected to be a widespread issue and
is mainly a symptom of week winds coupled with temperatures falling
to dew points in the mid 40s where the fog is developing, with dew
point depressions in the 5-10 degree range elsewhere. Another
classic late Spring day is in store for us today with temperatures
in the 70s under mostly sunny skies until a chance for a few showers
and thunderstorms arrive by the afternoon from a weakening upper
level trough centered over Ontario. Northwesterly flow aloft will
allow for a transient shortwave to push across north-central
Minnesota to western WI, with the best chance for seeing showers and
a few thunderstorms in far eastern MN and western WI from roughly
1pm to 5pm this afternoon. A few severe storms are possible mainly
for wind gusts spurred by a stronger shower or two with fairly weak
instability in the 250-500 J/KG range per RAP forecast soundings
over New Richmond WI with lower amounts west. The sounding profile
is dry adiabatic at ground level with dew points being the primary
limiting factor in regards to surface based convection with LCL
heights above 3000ft as a result making for lower end strong
thunderstorm potential. AVA on the western side of the trough will
clear skies out by the evening with clear skies continuing through
Saturday and for most of Sunday before our next chance for showers
and storms arrives. The clear skies will also allow a chance to
see the northern lights due to a geomagnetic storm caused by a
series of CMEs. See the Space Weather Center`s webpage for more
specific details, the bottom line for us is a chance to see the
northern lights much later in the season than is typical and
right now skies look mostly clear at its peak tonight.

Saturday appears to be a perfect day to open the windows and enjoy
sunshine, low 70 high temperatures, and light winds at 5-10mph.
Northwesterly flow aloft continues with troughing to the east and
ridging to the west, with surface flow weak due to a lack of a
dominant synoptic scale surface based system. Flow aloft turns more
westerly by Sunday morning and a weak upper level trough occluding
over the plains should allow for southerly flow to increase at
ground level, with WAA coupled with sunny skies resulting in
temperatures approaching 80 for a high on Sunday in the Twin Cities
and upper 70s elsewhere. Sunday afternoon will also begin what looks
to be a trend for much of next week, that being zonal flow aloft
with embedded shortwave impulses allowing for sporadic shower and
storm chances but nothing that looks strong or significant.
Deterministic guidance is fairly consistent in showing a series of
shortwaves moving through the upper midwest, however without greater
instability or synoptic scale lift we are looking at isolated
chances for stronger storms. It is not until later in the week
towards next weekend where a stronger system begins to poke its
head, arriving late Wednesday to early Thursday with a negatively
tilting trough sweeping across the northern CONUS resulting in more
widespread showers and chances for storms due to stronger forcing.
The main question in regards to storm chances will be access to
moisture which right now looks decent with PWAT values from 1-1.25
on Thursday, however the greater access to Gulf moisture looks to
cutoff to the south likely resulting in stronger storms in the
central plains. For now, expect a `normal` late Spring to early
Summer weather pattern with isolated to scattered weak storms for
most of next week with a chance for more widespread rain on
Thursday.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1215 AM CDT Fri May 10 2024

SKC to FEW250 are expected throughout the period until around
18-20z when a chance for -TSRA arrives for eastern MN to western
WI, primarily affecting RNH/EAU with a slim chance for MSP/STC.
Otherwise a few gusts to 20-25kts are possible during the
daylight hours dropping back by 01-03z. VFR for all sites.

KMSP...The chance for -TSRA is less than a prob30 would cover
but is still non-zero, around 15 to 20 percent. CAM guidance
tonight suggests the activity should remain east of MSP.

/OUTLOOK FOR KMSP/
SAT...VFR. Wind NW 5-10kts.
SUN...VFR. Wind W 10-15G25kts.
MON...VFR. Wind N 10-15kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...Frost Advisory until 8 AM CDT this morning for Barron-Chippewa-
     Eau Claire.
     Freeze Warning until 8 AM CDT this morning for Rusk.

&&

$$

DISCUSSION...TDH
AVIATION...TDH