Scientific Forecaster Discussion
fxus63 kmpx 252017
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
317 PM CDT Thu may 25 2017
Short term...(this evening through friday)
issued at 245 PM CDT Thu may 25 2017
Main issue this period is the incoming frontal boundary and
associated weather concerns as showers and thunderstorms will be
possible tonight through tomorrow.
Low pressure system continues working east across southern
Saskatchewan with a southward trailing cold front currently across
the central Dakotas. We continue to see south-southeast winds ahead of the
front which is mainly expected to move through our area tomorrow.
For the rest of today and tonight, isolated showers will move
through thanks to weak warm air advection and a subtle upper low
ripple in the flow. More broad precipitation has developed in the
eastern Dakotas thanks to the proximity to the frontal boundary, and
those should impact western Minnesota this evening.
For tomorrow, temperatures should be a few degrees warmer in
southerly flow ahead of the front. By 18z, expect the front to be
draped from north to south through The Heart of Minnesota and
continued to advertise the chance for showers and thunderstorms
tomorrow afternoon along and east (ahead) of the frontal boundary.
Limited forcing and instability are the reasons we went with 40-50
pops for now but those certainly could be increased if confidence the
chance for shower and storm development and coverage increases.
Long term...(friday night through thursday)
issued at 315 PM CDT Thu may 25 2017
For the upcoming Holiday weekend, it looks as though the best day
for outdoor activities will be Saturday. Sunday and Monday look to
be cooler and breezy as another frontal boundary moves southward from
Not much change in the last several model runs as the
mean upper pattern remains locked in from a ridge in the west, and
a deep upper trough centered north of the Great Lakes. This will
keep our region cooler than normal, especially early next week as
the core of the coldest air mass moves overhead. Under the cooler
air mass, instability showers will likely develop, especially
Sunday and Monday afternoons during the typically diurnal period.
Highs on Monday, which is based on 92/85h temperatures, could
easily be lower than 60 degrees.
However, before the next front moves southward late Saturday, and
in between a storm moving across the Central Plains, our region
should see temperatures near normal with highs in the low to mid
70s. Typically the last week of may has average highs in the low
to mid 70s which hasn't occurred for most of southern Minnesota
since the 16th.
There is a sign that this pattern will begin to change late next
week as the mean upper ridge in the west moves over The Rockies,
and into the plains. Even some of the longer range /gefs/
ensemble members have temperatures starting to modify late next
week, with a few members forecasting highs above 80 degrees. This
pattern change will also lead to more stormy conditions as the
upper level flow becomes more west/southwest the first week of
Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 1254 PM CDT Thu may 25 2017
The guidance is forecasting a chance for MVFR ceilings overnight
into early tomorrow morning, but we think the models are
overdoing the low level moisture and hence went with a VFR
forecast with clouds above 030. Main feature of interest is the
frontal boundary currently across the central Dakotas in a north
to south orientation. That front will slowly move east and push
through our area overnight through Friday from west to east.
Included a vcsh generally along and ahead of the front. Winds
will be southeast-south-southeast through most of the period, until that front
arrives in western Minnesota tomorrow morning and winds begin turning
Kmsp...with the front to the west still tomorrow afternoon, we
include a prob30 as there may be a few thunderstorms that
initiate along the front during the afternoon.
/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.