Scientific Forecaster Discussion
fxus63 kmpx 251142
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
642 am CDT Thu may 25 2017
issued at 631 am CDT Thu may 25 2017
Updated to include 12z aviation discussion below.
Short term...(today and tonight)
issued at 315 am CDT Thu may 25 2017
Surface analysis early this morning shows one low pressure system
over the central Ohio Valley region with another over the far
western Dakota. In between, weak high pressure prevails over the
upper Mississippi River valley. Aloft, one large upper level low
is located nearly atop the surface feature in the Ohio Valley
while a second large upper level low is sitting over southern
Saskatchewan province. In between, an upper level ridge axis
extends from western Ontario province southwestward to the Texas/OK
Panhandle area. The ridge will be the primary feature driving the
sensible weather over Minnesota/WI today with a mix of sun and clouds
along with comfortable high temperatures around 70 degrees. The
ridge will move off to the east tonight, allowing the warm front
from the western low pressure system to pivot north into southern
Minnesota by this evening and on into central Minnesota tonight.
In addition, the trailing cold front is expected to push east
through much of the state tonight, moving to nearly the Minnesota/WI
state line by daybreak Friday. While deep moisture will not be
considerably high, there will be enough moisture available for the
frontal system to use for generating at least isolated showers
this afternoon through tonight from west to east. Not looking for
much in the way of quantitative precipitation forecast at all, maybe a hundredth or two for most
spots if anything at all. As for temperatures, after the highs of
around 70 today, the additional clouds plus the passage of the
warm front will keep temperatures mild for tonight with lows in
Long term...(friday through wednesday)
issued at 315 am CDT Thu may 25 2017
The long term concerns remain timing of frontal passage Friday and
overall evolution of the long wave trough/closed low over the
northern Continental U.S. Over the Holiday weekend and early next week.
The front progresses east over the cwa during the day Friday. We
will hold onto the chance pops for this feature with thunder
chances into the afternoon. By tomorrow evening, the front will
have advances well into west central Wisconsin and should end the
rain threat in the evening there. Temperatures looks warm
along/ahead of the front with rising in the mid/upper 70s across
far southern Minnesota. More clouds to the north will limit heating
somewhat with readings around 70 common there.
Into Saturday, we may see some elevated showers linger to the
south during the day and then some encroachment to the northwest
in the afternoon as the upper trough approaches. Appears the GFS
is a little overdone on overall development into Saturday. We like
the drier European model (ecmwf) and Canadian model at this point as the upper jet
translates a bit farther to the southeast.
We still see some timing differences in the overall evolution of
the upper trough over the northern state. This will affect timing
of the cold front and development of more widespread cloudiness.
The GFS appears to be overdone on its leading short wave into
Sunday. We like the slower European model (ecmwf)/Canadian models which favor the
front to drop into the area Sunday afternoon and across the area
by Memorial Day. At the moment pops are probably a little low with
the trough moving in during this period. Hopefully, the models
will come to a consensus on this system during the day.
Temperatures are expected to remain in the lower 70s both
Saturday and Sunday, which is close to normal. However, with the
passage of the front, readings will cool back about 10 degrees
below normal again on Memorial Day.
Following this, we remain on the cool and mainly dry side into
midweek with a warming trend indicated later next week as ridging
aloft/warmer air builds over the western Continental U.S..
Aviation...(for the 12z tafs through 12z Friday morning)
issued at 635 am CDT Thu may 25 2017
Mainly high pressure to prevail today but a warm front will
approach this evening and lift north through the area tonight.
Clouds will be on the increase, mainly in the mid-levels, today
into tonight and remain overnight. A few showers are possible in
eastern Minnesota into western WI but nothing that is expected to reduce
visibility. Some patchy ground br/fog is around this morning but
this will eventually burn off, resulting in solid VFR conditions.
Kmsp...some mid-level clouds will approach from the east but these
may be overtaken by the high clouds moving in from the west. VFR
either way. Small shot at some showers overnight through the
morning push tomorrow so have included the vcsh but chances are
low msp actually receives measurable precipitation.
/Outlook for kmsp/
Sat...mainly VFR. Slgt chc p.M. -Shra/-tsra. Wind west 5-10 kts.
Sun...mainly VFR. Chc -shra/-tsra. Wind northwest 5-10 kts.
Mon...MVFR possible. Chc -shra/-tsra. Wind northwest 5-10 kts.