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fxus63 kmpx 170509 
afdmpx

Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
1209 am CDT Mon Jun 17 2019

Updated for 06z aviation discussion...
issued at 1201 am CDT Mon Jun 17 2019

&&

Short term...(this evening through Monday night)
issued at 238 PM CDT sun Jun 16 2019

Not a lot happening during the short term as a very weak boundary,
currently stretched out from near Redwood Falls to Long Prairie,
gradually shifts east through Monday night. Satellite this afternoon
shows some bumpier cu going up along this diffuse boundary, but it's
doing so in environment with MLCAPE values of 100 or 200 j/kg, with
little forcing on the front and the main upper forcing coming out of
nodak and remaining to our north. Through the rest of the afternoon,
showers will continue to try and develop near the boundary, but will
quickly dissipate with the setting sun. As the wave over nodak
works across northern Minnesota, we could see the southern extent of its
precip move across our far northern County Warning Area (central Minnesota into northwest wi), but
even that looks like a stretch. The bigger question for tonight is
what happens with cloud cover. Some indications we could see stratus
develop again, but as mentioned in the aviation section, model
agreement on whether or not we actually see anything develop is
pretty low, so stuck with the nbm for cloud cover, which basically
has a scattered coverage through the night.

For Monday, it's a repeat of today, but the boundary will slowly be
pivoting southeast across the area Monday into Monday night. The
main upper wave will be moving across northern Minnesota into Lake
Superior, which is what will drive the north end of the boundary
east, but the south end of the boundary down toward Omaha will
remain stationary. Slowly slid pop gradient southeast with expected
motion of the boundary, but like today, convergence on the boundary
looks weak and instability is low, so very sparse coverage at
best is expected with any diurnally driven activity. What will be
nice is models continue to slowly nudge up temperatures for Monday,
with highs expected to get right up in the 75 to 80 range.

Long term...(tuesday through sunday)
issued at 238 PM CDT sun Jun 16 2019

Overall large scale pattern evolution.
West to west-northwesterly upper flow at the start of the period
looks to evolve into southwest flow by late week as troughing
amplifies in western US/Canada. That upper trough then looks to
swing through the upper Midwest over the weekend, although its
timing and amplitude is highly uncertain at this point. After that
most indications are that we'll see heights build across the central
and eastern US, which would lead to much warmer and potentially more
active weather for our area.

Model consistency and preferences.
Guidance is in decent agreement through midweek, but differences
become more noticeable from the second half of the week into the
weekend as the flow amplifies. Given significant spread in the
ensemble systems (in addition to marked differences in the
deterministic guidance) don't see much reason to stray too far from
the nbm/consensus approach. If anything, might shy away from some of
the details offered by the GFS given its outlier overly developed
upper and surface lows in the northern High Plains Friday.

General forecast overview.
Precipitation chances on Tuesday look like they should stay south
near the I-90 corridor (and southward), with the instability
gradient being depressed into that area. The guidance does show some
spotty precipitation farther north, but most is light and coming
from the various model cp schemes. Dry weather for most of the area
should continue into Wednesday before we eventually get into return
flow/warm advection and see instability work back into the area late
Wednesday and Wednesday night. Chances for rain showers/thunderstorms and rain should work
from west to east across the area Wednesday night and Thursday. With
significant disagreement in the guidance beyond that point, and with
instability lingering over the region while we await the arrival of
the western trough, we'll have a long period of chance pops from
Friday through Sunday. The best chance for heavier and more
widespread precipitation looks to be from Friday night through
Saturday.

Forecasts concerns and/or targets of opportunity.
Primary concerns for any significant weather look to hold off until
the tail end of the forecast period when we have more meaningful
instability in place along with the arrival of a healthy upper wave
moving in from the western US. However, given the significant
uncertainty in the guidance there isn't much to justify changing the
consensus forecast at this point. In the shorter range, Tuesday
provided somewhat of a target of opportunity with respect to
precipitation chances, and tightened up the pop gradient (and
shifted it slightly south) on Tuesday to line up better with where
the baroclinic zone and any associated instability look to be.

&&

Aviation...(for the 06z tafs through 06z Monday night)
issued at 1201 am CDT Mon Jun 17 2019

VFR conditions for most locations in western Minnesota, but an
area of MVFR stratus along the Mississippi River will lift
northwest and could affect kmsp, krnh, and Keau. Some patchy fog
is possible as well. Could see a few showers and thunderstorms
develop again tomorrow afternoon, with better chances in western
Wisconsin. Winds will be light.

Kmsp...
an area of MVFR clouds will lift northwest and could impact kmsp,
so have lowered the clouds below 1700 feet since ceilings are
lower than that already. This area of clouds may stay just to the
east of the air field, but this did speed up the timing of the
lower ceilings.

/Outlook for kmsp/
Tue...VFR. Wind northwest 5-10 kts.
Wed...VFR. Wind southeast 5 kts.
Thu...VFR. Chc MVFR/-tsra. Wind southeast 5-10 kts.

&&

Mpx watches/warnings/advisories...
WI...none.
Minnesota...none.
&&

$$

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