Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kmpx 231930 
afdmpx

Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
230 PM CDT Fri Aug 23 2019

Short term...(this evening through Saturday night)
issued at 215 PM CDT Fri Aug 23 2019

Little change in pattern through Saturday night. Highs pressure
will remain in control keeping area dry and slightly below
normal temperature wise.

Another cool night with light winds and clearing sky. Should see
lows tonight drop into the upper 40s far east and 50s generally
elsewhere.

High pressure will retreat slowly over the northeast Continental U.S. By
Sunday morning. Southeast winds will increase over the west
Saturday ahead of the incoming upper trough and pressure falls.
Expect more diurnal cumulus much of the area Saturday but
shouldn't limit afternoon highs warming through the mid/upper 70s.

Still most deterministic models trending slower with incoming
Dakotas trough. Will hold onto a slight chance pop far west
central County Warning Area after 09z Sunday.

Long term...(sunday through friday)
issued at 215 PM CDT Fri Aug 23 2019

The overall focus in the extended forecast continues on mainly the
Sunday night thru Monday timeframe for fairly widespread rain
across the area while temperatures start out near normal in the
first half of the week then drop to below climatological norms in
the latter half.

To start out Sunday, high pressure will be centered over New
England, underneath a definitive upper level ridge over the
northeast Continental U.S.. a weaving cold front will extend southwest from
Hudson Bay into northeastern Montana into northwestern Wyoming. A pair of
identifiable low pressure centers over the western Dakotas will
merge over the weekend, aiding the cold frontogenesis. An upper
level trough will continue to lumber its way eastward Sunday night
into Monday, sitting atop the upper Mississippi River by daybreak
Monday. The cold front will trail the upper level feature a bit,
moving into western Minnesota early Monday. Deep moisture will accompany
these surface and upper features, some from the Pacific with the
trough and some from the deep south in the low-to-mid levels in
advance of the systems. This will all contribute to the
development of fairly widespread showers with some thunderstorms
spreading east across Minnesota/WI mainly Sunday night through most of
Monday. Sufficient dynamics along with the steady progression of
this system should allow quantitative precipitation forecast to easily reach 1-2" for much of the
weather forecast office mpx coverage area during this event.

This cold front will move into WI late Monday then across the
Great Lakes Monday night into Tuesday, away from the coverage
area and bringing an end to the main rain threat of the extended
forecast. A secondary cold front looks to drop south through Minnesota/WI
during the middle of next week but this front will be rather
progressive, have much less moisture available and not have any
impressive upper level support for much in the way of
precipitation.

That being said, the cold front for next week does look to bring
in noticeable cold air advection with is passage. This means
that below normal temperatures will very likely be realized for
the latter half of next week.

&&

Aviation...(for the 18z tafs through 18z Saturday afternoon)
issued at 1150 am CDT Fri Aug 23 2019

Persistent band of low level moisture remains trapped under
subsidence inversion affecting mainly eastern area. Brief period
of lower end MVFR across southern Metro lifting quickly through
18z. Will mention scattered-broken scenario but will maintain VFR through
period. Diurnal trend in clouds should clear through 03z. Then
some high clouds possible over the west as Dakotas trough slowly
approaches. More diurnal cumulus expected Saturday as well.
Increasing southeast winds into Saturday morning with gusts around 30kts
possible by 18z Sat at kaxn/krwf.

Kmsp...no additional concerns.

/Outlook for kmsp/
Sat night...VFR. Wind southeast 10 kts.
Sun...MVFR/IFR psbl. Chc of PM -tsra. Wind southeast 10g20 kts.
Mon...MVFR psbl. -Tsra likely. Wind S 10-15 kts.



&&

Mpx watches/warnings/advisories...
WI...none.
Minnesota...none.
&&

National Weather Service Glossary of Abbreviations