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FXUS63 KMPX 280341

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1041 PM CDT Mon Mar 27 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 315 PM CDT Mon Mar 27 2017

Regional visible satellite imagery indicated a fine line of low
clouds, mixed with fog/drizzle in portions of west central
Wisconsin, and south central Minnesota, had slowly eroded along 
the northern edge this afternoon. Temperatures under the denser
cloud cover only managed to rise into the 40s, compared to the mid
to upper 50s where sunshine was abundant in the west and central
part of the state. 

The main concern overnight is the relatively light winds in the 
boundary layer, coupled with abundant moisture near the surface, 
to lead for areas of fog to form. HRRR, and other models that 
have a visibility parameter, do indicate an expanding area of fog 
in south central/southeast Minnesota this evening. The only 
parameter that makes things more unlikely for dense fog to form is
the current cloud cover. This area needs to be watched for the 
possibility of a dense fog advisory if conditions warrant. 
Elsewhere, patchy to areas of fog are likely, but not as 
widespread as in the southeast part of the state. Therefore, I 
have continued the trend of widespread fog south and east from 
Mankato to Red Wing. Any fog that forms overnight should dissipate
by mid morning Tuesday with more sunshine likely by the afternoon
than today. Temperatures should reflect more sunshine with highs 
in the 50s, to lower 60s. 

.LONG TERM...(Tuesday night through Monday)
Issued at 315 PM CDT Mon Mar 27 2017

The atmosphere is caught in a repeating pattern with a highly 
amplified trough that digs over the west coast. Eventually this wave 
becomes cut off from the main flow as a northern stream ridge breaks 
onshore the Pacific Northwest. The cresting ridge sends the northern 
stream jet along the International border, leaving the Midwest in a 
split flow regime.

No significant changes from the previous forecast. Model trends 
continue to show the precipitation being centered over Iowa and 
Wisconsin for Wednesday and Thursday. Still have chances for rain 
across the far southeast part of the forecast area, but any rain that 
does occur will only amount to a few hundredths of an inch. 

That's about it for precip chances over the next 7 days for the 
Upper Midwest. the 7-day rainfall total off from the Weather 
Prediction Center has a dry area over much of the NWS Twin Cities 
forecast area, and based on the 27.12 GFS/GEM/ECMWF have little 
evidence to disagree with that forecast. Temperatures will continue 
to be around 5 degrees above the seasonal average for late March 
heading into early April.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1035 PM CDT Mon Mar 27 2017

Will look for low clouds/fog to develop over much of the WFO MPX
coverage area overnight, particularly in south central/southeast 
Minnesota then slowly spread east/northeast across eastern 
Minnesota into western Wisconsin. Depth of the moisture remains 
shallow so only expect MVFR fog for the most part but some IFR
visibility cannot be ruled out. Clearing will then take place
shortly after daybreak, resulting in solid VFR conditions
tomorrow. Winds will remain light from the north/northeast, and 
more east Tuesday morning. 

KMSP...Main issue will be fog development during the Tuesday
morning push. Seeing MVFR visibilities are certainly reasonable
with a small duration of IFR visibility not able to be ruled out.
Low stratus does not look to be an issue due to rather light winds
being more conducive to fog development but moisture advection
into the area overnight will be key. Winds will remain at or below
7 knots throughout this TAF period.

Wed...VFR. Chc -RA late. Wind ESE at 7-10kts.
Thu...VFR. Chc -RA. Wind E at 8-10kts.
Fri...VFR. Wind NE 4-8kts.



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