939
FXUS63 KMPX 032023
AFDMPX

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

.KEY MESSAGES...

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

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

&&

.DISCUSSION...
Issued at 312 PM CDT Wed Jul 3 2024

If you`re a fan of fair weather days... enjoy this one while it
lasts! Temperatures will drop into the mid-low 70s around sunset,
and cloud cover will begin to increase from the southwest overnight.

The upper trough over the northern Rockies is still on track to
deepen and develop a closed low as it moves east into the Upper
Mississippi Valley early tomorrow. A band of showers and few storms
will likely develop along the warm front across western MN shortly
after midnight, eventually expanding north and east throughout the
morning. Outside of some isolated precip, most locations will likely
see a few hours of dry conditions before more scattered to widespread
showers and storms develop during the afternoon. CAMS continue to
favor less of a widespread heavy rain event, and more of a localized
concern depending on what areas see the strongest and most numerous
storms. In other words, a broad swath of 1+ inches of rain is
still expected across southern and central MN, but CAMS suggest
that only a county or so will see values in excess of 2-3
inches. The area of focus looks to be somewhere within south-
central MN (just west of the TC metro) where the deformation
zone is expected to set up (northwest of the surface low). HREF
probabilities have a line of 40-60% chance for greater than 2
inches of rain (in 24 hours) extending from Redwood Falls up
towards Rogers, MN. As we head into the evening, precip should
become more isolated across southern MN while showers and storms
closer to the low should be favored with the continued synoptic
lift.

A few strong to severe storms are possible during the afternoon and
evening, however a few factors could limit things. 1) Lapse rates
will be modestly steep at best (about 6-7 C/km); 2) Extensive cloud
cover could limit instability, with only 500-1500 J/kg of CAPE
expected (greatest over southeast MN); 3) elongated/straight
hodos suggest splitting cells could interact/interfere with one
another; and 4) vertical wind shear will also be somewhat modest
(25-35 kts), potentially limiting storm organization. That
said, all hazards will be on the table for any storm that is
able to develop and become organized. Given the relatively
cooler temperatures aloft and the hodo signatures, hail
development would be favored, with a few instances of large hail
possible. This hail threat was noted as the main reasoning for
our upgrade to a Slight risk (level 2 of 5) on the SPC Day 2
Convective Outlook. Non-supercell tornadoes/funnels will also be
possible, especially near the surface low as it tracks through
southeastern MN. Bursts of heavy rain and strong winds will be
likely with any organized storms as well.

Several more chances for rain will be possible through the middle of
next week as the upper level heights remain in a western ridge,
central trough pattern. QPF amounts continue to look meager from
event to event, but could total up to an additional 1-2 inches for
some through this period. Temperatures will stay near or below
normal into next week, before potentially climbing as we head into
mid-July. Both the GEFS and EPS suggest a few days in the 90s will
be possible, but this will largely be dependent on how/if the ridge
over the western CONUS builds eastward.

&&

.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...BED
AVIATION...CTG