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Area Forecast Discussion (AFD)

Issued by Duluth, MN (DLH)

FXUS63 KDLH 202334

Area Forecast Discussion
National Weather Service Duluth MN
634 PM CDT Fri Apr 20 2018

.SHORT TERM...(This evening through Saturday)
Issued at 317 PM CDT Fri Apr 20 2018

High pressure over the Great Lakes region will maintain mostly
clear skies across the Northland. Temperatures will once again
plummet below freezing tonight thanks to clear skies, calm winds,
and low humidity. Leaned on the colder side of model guidance for
overnight lows.

Light southerly winds will develop Saturday and make for an even 
warmer day than today. Leaned on the warmest model guidance, 
especially the bias- corrected GFS. Highs should be in the upper 
50s to lower 60s. Expect a weak lake breeze near Lake Superior
because of the light wind field inland and the stark temperature
difference from the Lake to inland areas.

.LONG TERM...(Saturday night through Friday)
Issued at 317 PM CDT Fri Apr 20 2018

A ridge will build from the Upper Mississippi River Valley late 
on Saturday into eastern portions of Ontario and the Central Great
Lakes on Sunday. Behind the ridge, a trough will lift into 
Central portions of Canada. At the surface high pressure will 
build into the Central and Eastern Great Lakes, while a cold front
slides across the Eastern Dakotas into western portions of 
Minnesota by Sunday evening. Flow aloft will become more 
southwesterly, which will warm air into the region aloft. In 
addition, winds will be gusty due to the tightening pressure 
gradient and deep mixed layer developing. Due to the combination 
of these things opted to increase high temperatures and lower 
relative humidities. A bit concerned that winds may be higher and 
relative humidities lower across north central portions of 
Minnesota. High temperatures on Sunday range from the low 50s 
along the Lake Superior shoreline, to the upper 50s and low to mid
60s inland. 

The trough will continue lifting northeastward on Monday into 
Hudson Bay, while the surface cold front slides through much of 
Minnesota. There are slight chances of a few rain showers 
developing across portions of northeast Minnesota during the early
morning hours. Despite the front passing through, warm 
southwesterly air will advect into the region. This will bring the
mildest readings of the extended with highs in the mid 50s along 
the Lake Superior shoreline and the low to mid 60s inland. 

The forecast becomes a little more uncertain on Tuesday as an 
area of low pressure develops across the Central/Northern Plains. 
A trough will dig from western Canada/Intermountain on Monday into
the Northern Plains and Upper Mississippi River Valley by late 
Tuesday. This may bring the next shot of widespread precipitation,
however there is a lot of spread between deterministic guidance 
at this point in time of the track, speed and intensity of the 
low. The GFS is the most robust with precipitation across the 
Northland - due to the northerly track of the low, while the ECWMF
continues to show little if any precipitation due to a southerly 
track of an innocuous low. The GEM is a compromise between the 
two, but suspect the ECMWF is on the right track based on previous
systems moving through the area. Regardless temperatures will 
cool down in wake of the system trough moving through. Behind the 
exiting system, high pressure will build in on Wednesday before 
another wave moves in from the northwest on Thursday. High 
temperatures on Tuesday, Wednesday and Thursday range from the 
upper 40s to the mid 50s. 


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 633 PM CDT Fri Apr 20 2018

High pressure will remain in control of the Northland weather
throughout the period. Only some thin high clouds will move
through at times, with VFR conditions during the TAF period. 


DLH  31  57  28  61 /   0   0   0   0 
INL  29  60  32  63 /   0   0   0   0 
BRD  29  60  32  62 /   0   0   0   0 
HYR  26  57  26  59 /   0   0   0   0 
ASX  29  59  27  59 /   0   0   0   0 




SHORT TERM...Grochocinski