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162
FXUS63 KMPX 271813
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
113 PM CDT Thu Jun 27 2024

.KEY MESSAGES...

- Next round of active weather arrives late this evening and
  continues into Friday. Slight Risk (Level 2/5) for severe
  weather across south central Minnesota Friday, where
  scattered strong to severe storms are possible.

- Quiet weekend weather on tap, followed by the next weather
  system capable of producing heavy rain and possible severe
  storms Monday into Tuesday.

&&

.DISCUSSION...
Issued at 305 AM CDT Thu Jun 27 2024

Mostly clear and quiet across Minnesota and western Wisconsin this
morning with temperatures that have dipped into the 50s to low 60s.
Morning sunshine will give way to increasing mid to high level
clouds ahead of the next round of active weather approaching from
the west. More on that in a moment, but the bottom line up front is
that today will be dry for most locations. The exception will be
across western Minnesota where ~30-40% PoPs arrive during the
afternoon as a band of light showers moves in. The showers will be
up against dry air in the low-levels as indicated on forecast
soundings, likely working to limit QPF and eastward extent of
the shower coverage through this evening. Highs climb into the
70s one again, so it should be a relatively nice day of weather
for most locations despite the increasing clouds.

GOES water vapor imagery captures an upper-level trough moving
ashore in the Pacific Northwest, with a region of broad ascent
across the Rockies. A mid-level shortwave will develop across the
northern Great Plains in response to the eastward movement of the
upper trough. Warm/moisture advection will increase into the Upper
Midwest ahead of shortwave and PWATs will surge to high end of
sounding climatology (~1.6" to 1.7"). Initial rounds of showers,
like the the one referenced above, will struggle to produce more
than a few hundredths of QPF due to low-level dry air, but ongoing
isentropic ascent, a strengthening LLJ, and mid-level frontogenic
forcing will help to saturate the column and produce widespread rain
across the region late tonight into early Friday. Limited instability
and only a few hour residence time at any one location should help
keep QPF in check through mid-morning Friday, with generally a
quarter to half inch expected. There is a signal for higher
amounts to the north of I-94 in central Minnesota, where the
frontogenic forcing may help to produce heavier rainfall rates.
Still, the blended solution keeps QPF under an inch in these
areas.

The evolution of the forecast becomes a bit more uncertain after mid-
morning Friday. A surface low is forecast to move northeast through
the Dakotas Friday morning, with an associated warm front set to
lift north into southern Minnesota. The northward progression of the
warm front will have large implications on how the second half of
the day plays out. For those north of the front, forecast soundings
show limited instability due expansive low-level cloud cover that
looks like it will be slow to clear. A different story may develop
south of the warm front, where potential clearing and theta-e
advection will allow for moderate destabilization across a region
that features veering hodographs, sufficient shear, and ample
moisture capable of producing strong to severe thunderstorms.
The SPC has introduced a Day 2 Slight Risk (2/5) for locations
along and south of I-94 in south central Minnesota. A Marginal
Risk remains in place across central Minnesota and western
Wisconsin. Questions regarding the northward extent of the warm
front and resultant destabilization make this a highly conditional
setup that bears watching over the next 36 hours. The eastward
progression of the surface cold front will act as the primary
forcing mechanism for renewed convection Friday, it`s just a
question of how strong the storms will be. Should the threat
materialize, all hazards would be possible, especially damaging
winds and large hail. Right now it looks like communities along
and near I-90 would be favored for the best chance of severe
thunderstorms.

Convectively driven showers and thunderstorms will be capable of
producing locally heavy rain, which may push area storm totals into
the 1-1.5" range. This is not great news for ongoing river flooding,
but it does appear that another few days of dry time will follow for
the weekend. With that said, flash flood potential will remain high
with any additional rainfall given the recent wet pattern. Highs
take a step back into the upper 60s and low to mid 70s on Saturday,
and then warm into the low 70s on Sunday.

The unsettled weather pattern will swing another trough through
central CONUS Monday into Tuesday, with the Upper Midwest in line
for another round of heavy rain and potential severe weather. A wing
of warm advection aims to produce precipitation starting Monday
afternoon, further increasing in coverage as the LLJ intensifies
later Monday, and continuing into the start of Tuesday. QPF from the
global ensemble suite averages between 0.5-0.8" across all south
central Minnesota and western Wisconsin. In fact, 75-80% of ensemble
members produce QPF amounts greater than a quarter of an inch. It`s
too soon to have a better handle on the degree that convection may
enhance the QPF amounts, but that should come into better focus this
weekend as the hi-res solutions come into play. There may also be a
severe weather threat Monday/Tuesday, which is hinted at by CSU-ML
probabilities. Significantly higher probabilities exist to the south
of Minnesota & Wisconsin, where a more favorable thermodynamic
regime would fit the conceptual model. As far as Independence Day
events, the latest guidance has trended wetter for next Thursday due
to a quicker approach of a late week system.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
-- Changed Discussion --
Issued at 111 PM CDT Thu Jun 27 2024

VFR becoming MVFR and possibly IFR this evening and
tonight. A band of showers continues to move in across western MN
with low VFR cigs extending well out ahead of the line as far east
as KMSP. Cigs will gradually degrade to MVFR heights across all
sites this evening once the showers approach. -TSRA is possible with
a secondary band of precip that develops and passes through
overnight. Precip will clear from west to east after 12z
tomorrow morning. Showers may linger into the late morning for
RNH and EAU sites. SSE`ly winds increasing late tonight with
gusts ranging between 18-25kts.

KMSP...Low VFR cigs becoming MVFR over the next few hours as a band
of -SHRA progs across western MN this afternoon. This area of precip
should reach KMSP around 02z but impacts should remain above
critical thresholds. -TSRA is possible with a secondary band of
precip overnight. SE winds will increase as showers approach
overnight with gusts nearing 30kts about 12z. Showers will
linger through the morning and leaving MVFR cigs and mist in its
wake in the afternoon. Winds becoming SW`ly in the afternoon
with gusts up to 18-20kts.


/OUTLOOK FOR KMSP/
SAT...VFR. Wind NW 10-15G25 kts.
SUN...VFR. Wind N bcmg E 5-10 kts.
MON...VFR/MVFR, chc -TSRA. Wind SE 10-15G25 kts.
-- End Changed Discussion -- &&

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

&&

$$

DISCUSSION...Strus
AVIATION...Dunleavy