Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kmpx 221128 

Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
528 am CST Fri Nov 22 2019

issued at 516 am CST Fri Nov 22 2019

Updated to include 12z aviation discussion below.


Short term...(today through saturday)
issued at 244 am CST Fri Nov 22 2019

Surface analysis early this morning shows extensive high pressure
sitting over the central Continental U.S. With a potent cold front well to
the south and east of MN/WI. High pressure also extends west into
The Rockies. Aloft, solid northwest flow is in place while a weak
shortwave trough travels atop the area.

This shortwave is responsible for cloud cover remaining in place
early this morning, but the back edge over western Minnesota is slowly
eroding eastward. As the day progresses, drier air moving into the
area along with the departure of the shortwave will allow skies to
clear out, making for sunny skies for the afternoon hours. Despite
the ample sunshine, the strong cold air advection will maintain
its hold as highs will only reach the lower 30s to lower 40s
today (but this is a strong recovery from the teens recorded early
this morning).

The upper level flow will flatten out a bit going into Saturday
while the high pressure area moves off to the southeast and a weak
storm system over western Canada drives eastward. The movement and
location of these features will combine to make for modest warm
air advection to develop tomorrow. While a couple weak shortwaves
aloft will push through, these features will do nothing more than
produce a slight uptick in cloud cover. Otherwise, slightly warmer
temperatures can be expected; highs will climb to the mid 30s to
the mid 40s.

Long term...(saturday night through thursday)
issued at 244 am CST Fri Nov 22 2019

If anything, there is more confidence in having a drier extended
period than multiple periods of rain/snow in the forecast.

A cold front will drop into the Pacific northwest from the Gulf of Alaska
over the weekend. This cold front will then press east across The
Rockies and through the northern plains Sunday-Monday, then
slowing down as it moves only into the Great Lakes by Tuesday
morning. While the main low pressure centers associated with this
system will remain to the south and east of the weather forecast office mpx coverage
area, enough moisture in the vicinity of the front will be
available to produce some isolated to scattered rain/snow showers
over mainly the northern and eastern portions of the coverage area
(a.K.A. I-94 corridor and northward). Not looking for anything
significant out of this system. While a few isolated rain/snow
showers are possible on the backside of the cold front for Tuesday
and Tuesday night, chances for even measurable precipitation
continue to dwindle as models suppress any low pressure center
expected to develop along the front off to the south and east of
the coverage area.

High pressure then returns to the central Continental U.S. For Wednesday and
Wednesday night, thus making the Wednesday pre-Thanksgiving travel
day free of precipitation for the upper Mississippi River valley

For the end of the week, uncertainty continues to prevail as the
deterministic models still run a split flow regime. There is some
better agreement in that both the GFS and European model (ecmwf) develop a potent
low pressure system over The Rockies Wednesday and Wednesday
night, then quickly shift it northeast and into Canada while still
to the west of the weather forecast office mpx coverage area. This would then spell a
warming trend and a relatively drier system, not something that
would bring a widely impactful system. In fact, it appears to be a
combination of rain and snow at this point with relatively little
quantitative precipitation forecast. So, again, nothing significant for the area while
temperatures run close to normal.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 516 am CST Fri Nov 22 2019

Swath of MVFR ceilings at initialization for nearly all tafs will
quickly erode after sunrise with drier air moving in and mixing
out the low level moisture, resulting in solid VFR conditions by
midday and lasting through Saturday morning. Winds will back to
southwesterly today and remain there through tomorrow. Speeds will
generally run close to 10kt but some gustiness may develop this
afternoon through tonight.

Kmsp...msp is sitting in a relative clearing "hole" while MVFR
ceilings are all around. As such, cannot discount the chance that
some MVFR ceilings may move back over msp before dissipating so
have handled this via tempo. Beyond that, no significant issues.

/Outlook for kmsp/
sun...VFR. Wind west 5 kts.
Mon...MVFR ceilings possible. Wind west 10-15 kts.
Tue...MVFR ceilings and -rasn possible. Wind northwest 5 kts.


Mpx watches/warnings/advisories...


National Weather Service Glossary of Abbreviations