Scientific Forecaster Discussion
fxus63 kmpx 232307
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
607 PM CDT Fri Jun 23 2017
Update...for 00z aviation discussion below
Short term...(this evening through saturday)
issued at 310 PM CDT Fri Jun 23 2017
A few random showers developed during the late morning/early
afternoon in an area of limited instability across
central/southwest Minnesota. Cloud cover and a persistent gusty
northwest wind also kept temperatures from rising too much during
the early afternoon. Although I can't rule out an isolated rumble
of thunder as a pocket of cooler temperatures move overhead this
afternoon, most of the precipitation is diurnally driven, so any
showers will die off quickly this evening.
A stronger disturbance that was diving south/southeast across
southern Saskatchewan will move across central/southern Minnesota,
and portions of west central Wisconsin Saturday afternoon. Colder
air aloft associated with the disturbance should allow for better
instability and hence, better coverage of precipitation than
today. Therefore, high chance, to likely percentages are noted
for Saturday afternoon in the southeast 1/3 of mpx forecast area.
As temperatures continue to cool in the boundary layer
tonight/Saturday, kept close to previous forecast temperatures in
the low to mid 60s for Saturday afternoon. This is 15 degrees
below normal for late June.
Long term...(saturday night through friday)
issued at 250 PM CDT Fri Jun 23 2017
Little change to the long term forecast period. The main topic of
discussion is the deep trough across eastern North America and when
the ridge to the west will displace the cool airmass from the upper
By tomorrow night, the longwave trough will really encompass the
eastern 2/3 of North America with 850h temps as low as +4c in the
area until the West Coast ridge can progress eastward early next
week. We'll see another shortwave drop down from Canada and bring
more chances for showers and thunderstorms on Sunday. Limited quantitative precipitation forecast
would accompany these showers and no severe weather would be
expected with any small storms that do form.
High pressure will fill on Monday which looks to be quite a nice day
weather-wise. Mostly sunny skies with winds of 5 to 10 mph, high
temps topping out in the low 70s and dew points holding in the mid
Winds will turn southerly and increase Tuesday on the back side of
the high as the upper ridge builds eastward across our area. This
will mark the return to near normal high temperatures for this time
of year with temps around 80 degrees Tuesday through Thursday. With
that though comes a higher chance of thunderstorms and deeper
moisture. Pops Tuesday night have been increased into the likely
category as shortwave moves in along with strong warm air and
moisture advection. That will be our next chance of widespread
Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 608 PM CDT Fri Jun 23 2017
Scattered showers and gusty winds will diminish in the first few
hours of the taf period, with decreasing clouds overnight.
Saturday will be similar to today, with gusty northwest winds
developing by late morning, along with broken-overcast stratocu
clouds. Showers and isolated thunderstorms will most likely be a
bit greater in coverage on Saturday afternoon, given a 500mb low
will be passing overhead.
showers around the field end by 01z, then scattering clouds
tonight until mid-morning Saturday. Shower coverage will be
greater for Saturday afternoon, with isol thunder possible as
/Outlook for kmsp/
sun...VFR. Chc MVFR with p.M. -Tsra. Winds northwest 10-15 kts.
Mon...VFR. Winds northwest 5-10 kts.
Tue...VFR. Chc thunderstorms and rain aftn, likely late. Winds S 5-10 kts.