946
FXUS63 KMPX 031717
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1217 PM CDT Wed Jul 3 2024

.KEY MESSAGES...

- Thunderstorms and locally heavy rainfall likely for Thursday
  and Thursday night.

- Chances for showers and a few thunderstorms will linger into
  next week with temperatures remaining below normal.

&&

.DISCUSSION...
Issued at 358 AM CDT Wed Jul 3 2024

Aside from some low stratus lingering in parts of western WI,
skies are clear across the Upper Midwest this morning. Water
vapor imagery shows several weak disturbances across the
northern Plains. These will continue eastward today and could
spark a few showers or storms across the northern half of MN,
but rising mid level heights and a dry atmosphere should limit
coverage of these to less than 20 percent. The rest of the area
could have some fair wx CU this afternoon with highs in the low
to mid 80s.

The trough over the northern Rockies will dig southeast tonight
and begin to reach the Upper Mississippi Valley late tonight and
early Thursday. Showers and a few storms will overspread western
MN after midnight and begin reaching eastern MN/WI by midday
Thursday. As the upper low continues across the northern Plains
and reaches MN late Thursday, it will continue digging and
become neutrally tilted. Forcing will become more focused and a
broad surface low will develop and track across southern MN.
Scattered to numerous thunderstorms are expected by afternoon,
which will continue Thursday night along and north of the low
track. Mid level lapse rates will remain poor and the prospects
of significant surface heating appear limited given the
extensive cloud cover, so instability will be lacking. However,
there is some potential for a few stronger storms with several
hundred joules of CAPE given moist surface conditions. Some
non-supercell tornadoes can`t be ruled out near the surface
low. This system is beginning to reach the window of the CAMs
and many of the members seem too sparse with precipitation -
possibly as a result of low instability. From a synoptic
standpoint, one would expect more widespread activity than the
CAMs would currently indicate. Nevertheless, even the less
bullish CAM output does generate some impressive totals locally
due to a combination of the location of the deformation zone
across central MN and WI and slow storm motions. Some localized
totals could exceed 2 or 3 inches, with some model output
indicating the potential for even higher values than that. Kept
PoPs in the 70s to 80s, but it doesn`t appear rain will be
continuous for many hours at a time in any given location.
Problem for Thursday evening will be determining where and when
specific locations will be impacted as activity could remain
more scattered than with other events recently. The showers will
linger into Friday across eastern MN/WI, but some activity
could redevelop farther west in the afternoon with breaks in the
clouds and some instability developing within the cyclonic
flow.

Multiple waves within a broad north central U.S. trough will
keep precip chances going for much of the remainder of the
period. Nothing looks particularly widespread or heavy, but it
will continue the gloomy and un-Julylike weather for the
region. Temperatures will remain below normal until if/when the
western Ridge builds east. Some of the extended guidance is
hinting at that possibility toward mid-July.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1153 AM CDT Wed Jul 3 2024

VFR conditions expected through tonight, but broken to overcast
skies and lowering cigs will move in from west to east during
Thursday morning. RWF looks to have a good chance to falling to
MVFR cigs towards the end of the period. Rain chances will also
increase from west to east during Wednesday morning as our next
system arrives with a band of thunderstorms possible across
western and southern MN. Due to this potential, have kept or
added PROB30s for -TSRA at most of our MN terminals with
visibilities dropping to MVFR within the heavier cores. Outside
of any storms, general conditions will be either scattered light
showers or overcast skies. Steady westerly winds will slow to
calm/variable overnight before becoming more south-
southeasterly near 5 knots Thursday morning.

KMSP...Have added a PROB30 from 15-18Z Thursday for the
possibility of some rain showers. Scattered showers and
thunderstorms become more likely heading thru Thursday afternoon
with the best timing for storms and MVFR after 22Z. Westerly
winds of 10-15 knots will gust to near 20 knots this afternoon.
Light southwesterly winds tonight will become easterly at 5-10
knots by 18Z Thursday.

/OUTLOOK FOR KMSP/
THU PM...MVFR/IFR SHRA & TSRA. Wind E 5-10 kts.
FRI...MVFR SHRA/TSRA likely. Wind N 10G20 kts.
SAT...Chance PM MVFR SHRA/TSRA. Wind SW 5-10 kts.

&&

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

&&

$$

DISCUSSION...Borghoff
AVIATION...CTG