Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 220907

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
407 AM CDT Mon May 22 2017

.SHORT TERM...(Today and tonight)
Issued at 329 AM CDT Mon May 22 2017

The short term concerns development of showers/thunder into the
afternoon and evening. Also threat of strong thunder over the far

Water vapor imagery showing the initial short wave exiting to the
east of the area at this time. This should exit the east by 12z.
The next short wave is moving into northwest South Dakota. This
is progged to move into the southwest portion of the cwa this
afternoon. NCAR ensemble showing mean LI and MUCAPE fairly meager
this afternoon and mainly along I90 region. GFS and NAM also show
some potential of MUCAPE to 500 j/kg this afternoon. Will continue
to trend PoPs toward likely over far south central MN later this
afternoon. Severe potential appears fairly limited but at least
some small hail will be possible with steep mid level lapse rates.
If enough heating does occur to the north...we may see an
isolated thunderstorm develop in the late afternoon/early evening
before diurnal trend kicks in. We should see temperatures warm
some the lower and mid 60s most areas.

Tonight the short wave exits to the southeast and the upper trough
drops south over the area. We should see increasing clouds/PoPs
especially to the west overnight as forcing moves into the central
part of area by 12z Tue.

.LONG TERM...(Tuesday through Sunday)
Issued at 329 AM CDT Mon May 22 2017

Tuesday...The day will start with the previous day`s low pressure
center located near KMKE while a large upper level low shifts into
central Minnesota. Due to the surface low and associated cold
front having passed through the area, instability will be
diminished but deep moisture will remain underneath the large cold
core low. Thus, the expectations are to have scattered to numerous
showers rotate through the area about the large upper low with the
potential that stronger showers could produce small hail (a.k.a.
graupel). The potential for precipitation will diminish going into
the evening hours Tuesday and early morning hours Wednesday as the
upper level low moves southeast of the area and deep ridging from
the western CONUS shifts east.

Wednesday and Thursday...Both days will be under the influence of
a drier airmass along with a large ridge axis moving into the
region. Surface high pressure will attempt to reassert itself but
the main influence during these two midweek days will be the upper
level low. This will spell clearing skies along with a noticeable
uptick in temperatures. Whereas highs hold in the 50s area-wide on
Tuesday, highs increase to the 60s on Wednesday then to around 70
on Thursday.

Friday through Sunday...A bit more unsettled pattern is expected
for the end of the week into the weekend, mainly due to Canadian-
centered low pressure areas both at the surface and aloft. There
is better agreement on the timing of the systems, as a cold front
looks to push through the area late Friday followed by a brief
respite from precipitation during the day Saturday followed by
another large upper level low which may again bring scattered
showers going into Sunday. There also looks to be little in the
way of airmass change with these systems as highs look to remain
in the lower 70s throughout this period.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1034 PM CDT Sun May 21 2017

We have one more batch of rain to work through WI at the start of
the 6z TAF period, then we look to remain dry this period, as
better shower chances stay to our north with the main upper low,
and to our south as a secondary shortwave sparks some TSRA Mon
afternoon from NE SoDak into northern IA. We will have VFR skies
as well and may actually see a descent amount of sun tomorrow
between the two areas of forcing. Monday night we`ll have to
watch for MVFR cigs dropping south out of northern MN. SREF probs
show them reaching AXN by the end of this TAF period, which has
support from an RH time-height cross section for the NAM as well.

KMSP...High confidence in TAFs this period. Only area of
uncertainty is with the last 6 hours. As we hit that point, the
core of the upper trough aloft will be moving overhead. Beside a
return of OVC skies (VFR most likely), there will be a threat for
some -ra as well, but we have lots of time to monitor that
possibility and it looks pretty low impact as well.

Tue...VFR. Chc MVFR/-shra. Wind NW becoming N 5-10 kts.
Wed...VFR. Wind NE 5-10 kts.
Thu...VFR. Wind SE 5-10 kts.




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