Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
254 PM CDT sun Oct 4 2015
Short term...(this evening through monday)
issued at 254 PM CDT sun Oct 4 2015
Scattered showers will zip northeast across west central
Minnesota for the remainder of the afternoon and early
evening...associated with a short wave progressing through eastern
South Dakota. Simulated radar reflectivity from the hrrr-CR has been
handling the activity the best today and gridded probability of precipitation from this
solution were blended in. After this upper air feature moves
by...dry weather is forecast for the remainder of the short term.
A general decrease in cloud cover is forecast during the day on
Monday. We have turned the corner on the cool temperatures with a
small but gradual warming trend seen going forward. Lows tonight
will be in the lower to middle 40s. Highs on Monday will range
from the lower 60s across west central Wisconsin...the middle 60s
in the Twin Cities...with upper 60s to around 70 across west
Long term...(monday night through sunday)
issued at 254 PM CDT sun Oct 4 2015
The weather pattern will become more progressive as the high
amplitude flow with cutoff lows transitions to a zonal flow with
two quick moving shortwaves prognosticated to affect the region beginning
Wednesday through the rest of the week. The first wave will bring
widespread rain across the region...with the best chance being
Wednesday night along and north of i94. The second wave will arrive
Saturday and is a classic Alberta clipper...but will be moisture
starved so may not see any measurable precipitation.
Wednesdays system will be set up by a weak cold front that will
slide southeast through the region on Tuesday. An upper level pv
anomaly that is currently sitting over the Gulf of Alaska will move
across the northern rockies on Wednesday and quickly draw the
aforementioned cold front back north as a warm front. H850 theta_e
advection and isentropic ascent will provide sufficient lift for
saturation...and expect clouds to overspread the region throughout
the day on Wednesday. The best chance for precipitation will be Wednesday
Forecast soundings show a thin ribbon of elevated instability across
the south...so have an isolated chance for thunder. However most
locations will only see persistent rain...with totals generally
ranging around a half inch to an inch...and higher totals possible
north of i94. This system will exit the region late Thursday...with
dry weather expected Friday. On Saturday another shortwave is
forecast to move across the upper Midwest. The European model (ecmwf) is faster than
the GFS...but neither solutions brings precipitation across the region
because the air is relatively dry in the wake of the previous
system...so expect clouds to increase Saturday...but not
anticipating measurable precipitation at this point.
Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 1240 PM CDT sun Oct 4 2015
Fairly thick coverage of cumulus clouds has recently developed
over eastern Minnesota and west central WI...and with cloud bases around
2500-3000 feet and broken coverage...MVFR ceilings could persist for the
next few hours. VFR is likely to return to all terminals by
sunset. However...guidance is becoming more favorable for a
stratus deck to push northwestward over the eau and rnh terminals
overnight through Monday morning. MVFR ceilings are once again
possible at these sites after 06z. Winds will remain light across
the region...generally out of the southeast through tonight becoming
southerly on Monday.
Kmsp...a broken deck of low cumulus clouds has quickly
developed...and MVFR ceilings are currently occurring at the terminal.
While these clouds could certainly become more scattered in the
next couple hours...cannot rule out MVFR ceilings during the early
evening. These low clouds will dissipate by sunset...and VFR is
likely for the rest of the period. However...a stratus deck is
expected to develop just to the southeast of msp between 09z-15z...so
there is a slight chance that MVFR ceilings could occur during that
time as well. Winds will remain light...veering from the southeast
tonight to southerly on Monday.
/Outlook for kmsp/
Monday...VFR. Wind S 5-8 kts.
Tuesday...VFR. Wind SW becoming northwest 5 kts.
Wednesday...VFR. Chance -shra late. Wind east-southeast 5-10 kts.