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Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
601 am CDT Thursday Apr 17 2014
Short term...(today and tonight)
issued at 414 am CDT Thursday Apr 17 2014
Early this morning...weakening surface low was moving east near La
Crosse, WI. This low will rapidly weaken as it moves across
Wisconsin today...but north to northwest winds across Minnesota will
remain blustery early this morning before the weakening pressure
gradient allows them to subside some. A mix of rain and snow across
west central Wisconsin early this morning will quickly dissipate and
move east over the next few hours. The tough part of this forecast
period includes predicting the extent of the stratus deck
today...and the maximum temperatures today considering all the fresh
snow cover and the pesky low clouds. The cloud cover looks to linger
across east central Minnesota through south central Minnesota...and west central
WI...while western and northwestern Minnesota remain partly cloudy. Lowered
temperatures slightly from most guidance across the snow pack...but
didn't go too crazy with that because it is middle April and deep
mixing can still occur in this situation. Otherwise...surface ridge
of high pressure builds in this afternoon and winds become calm this
evening under the ridge axis...another cool night is forecast with
sub-freezing temperatures expected across the forecast area.
Long term...(friday through wednesday)
issued at 414 am CDT Thursday Apr 17 2014
Surface ridging will push east early Friday with southeasterly
wind increasing through the day. A warm front pushing northeast
into far southwestern Minnesota may kick off a few showers over central
and western Minnesota. Models have been trending drier with the most
recent NAM now almost completely dry. Maintained slight chance
probability of precipitation...but they could be removed in future forecasts. Cloud cover
will be extensive in strong warm air advection environment...and when coupled
with increasing southeasterly wind and residual snow cover...will
bring a chilly day with highs in the 40s...except some 50s near
the Iowa border depending how far north the front can lift during
the day. Temperatures will drop off Friday evening before becoming
steady or slowly rise overnight following the passage of the warm
Low pressure will trek north across the Dakotas into southern
Manitoba Saturday. A cold front will stretch to the south into the
Midwest and eastern plains...but forcing will be weak with much of
the energy being deflected to the north. Not particularly excited
about shower chances Saturday...but they will be best across
central Minnesota. If some sun can break through...highs will reach the
60s which could tap enough elevated instability for a low
probability of thunder.
The front will slow Saturday night...eventually washing out across
the Great Lakes and middle Missouri Valley Sunday. Shower chances
will linger near this front across southeastern Minnesota and western WI. The rest of
the region will see clearing skies. Mild Pacific air will push
across the plains during this time and plentiful sunshine in much
of Minnesota will bring temperatures back into the 60s or low 70s.
Thermal ridging arrives Monday as 925 mb temperatures rise into the +14
to +16c range. Mixing to 850 mb will take full advantage of this
thermal ridging and temperatures will climb into the middle 60s to middle 70s.
As strong low pressure develops over the northern rockies by middle
week...the warm front will retreat and winds will back
easterly/southeasterly. This will mark a trend toward cooler temperatures
at least temporarily midweek...particularly as a band of showers
and thunderstorms develop north of the boundary. Very warm and
humid air in the warm sector will try to make an appearance by
Thursday pending the track of the low. This will bring increasing
severe weather chances...which bears watching.
Aviation...(for the 12z tafs through 12z Friday morning)
issued at 554 am CDT Thursday Apr 17 2014
We'll still see cyclonic flow across eastern Minnesota and western
Wisconsin through much of the day...so the question is how long
will the low stratus linger...which is a tough forecast as I
believe the hi-res models are being too pessimistic in this case.
So...expecting ceilings to slowly raise this morning as the
surface warms...and scatter out this afternoon as the surface
ridge pushes in from the west...and the cyclonic flow moves
further to the east. Otherwise a dry forecast period with
northwest winds becoming light and variable this evening under the
Kmsp...going against the rap which is pessimistic in scattering
clouds out as it wants to hold on to the stratus until this
evening. Thinking dry air advecting in and surface ridge will
scatter out the stratus faster (by the afternoon).
/Outlook for kmsp/
Friday...mainly VFR. Chance MVFR Friday night with -ra. Winds NE 5-10 kts.
Sat...mainly VFR. Chance MVFR with -ra. Winds east-southeast 10-15 kts.
Sun...VFR. Winds north-northeast 5-10 kts.
WI...Winter Weather Advisory until 7 am CDT this morning for wiz025-
Winter Storm Warning until 7 am CDT this morning for wiz015-016.