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Area Forecast Discussion (AFD)

Issued by Duluth, MN (DLH)

FXUS63 KDLH 252344

Area Forecast Discussion
National Weather Service Duluth MN
644 PM CDT Tue Jun 25 2019

.SHORT TERM...(This evening through Wednesday night)
Issued at 340 PM CDT Tue Jun 25 2019

An unstable/uncapped atmosphere with CAPE in excess of 1000 J/kg 
will cause a wave of unorganized convection to cross the region 
this afternoon and evening. While linear shear profile is 
conducive to splitting cells and limits strong rotating updrafts, 
there still may be a storm here and there that takes on some 
severe characteristics, but do not expect anything long-lived. 
Overall, broad area of convection will erode the available energy.
Lightning is probably the largest threat this afternoon with 
every cell quick to generate pulses. 

Convection should diminish after 8 PM and then die off completely
overnight. Winds will decrease quite a bit overnight and if they 
fall enough patchy fog may be an issue especially since the area 
will be saturated due to the numerous showers. Tomorrow 
instability sneaks back in, but the forcing is much weaker, so not
expecting as widespread shower coverage as today. Temperatures 
continue to climb into the 80s.

.LONG TERM...(Thursday through Tuesday)
Issued at 340 PM CDT Tue Jun 25 2019

A sultry airmass will make its way into the Northland for much of
the long term. Temperatures will climb near to slightly above 
normal for afternoon highs. Several rounds of showers and 
thunderstorms are possible during the period. A passing shortwave 
trough will ride eastward along a stationary front and will 
support showers and storms on Thursday. A few strong to severe 
storms are possible and there is a potential for heavy rainfall. 
Precipitable water along and south of the front will climb over 
1.5 inches by Thursday afternoon. 850 mb moisture transport feeds 
into the frontal zone from the south, which should support 
repeated thunderstorm generation and training storms. Deep layer 
shear of 30 to 40 knots is forecast along and south of the surface
front which will raise the potential for organized convection.

Rising heights are expected over the area for Friday as a 
longwave trough digs into the western United States. Resultant 
surface high pressure and subsidence should provide a mainly sunny
to partly cloudy day along with a limited risk of rain and 

Another round of thunderstorms is possible Saturday and Saturday 
night. Convection is expected to fire in eastern Montana, western 
North Dakota, and adjacent areas of the Canadian Prairies Friday 
night and may advance eastward along the international border into
northern Minnesota by Saturday evening. Afternoon showers and 
storms may fire ahead of the convective wave. Some storms during 
the afternoon and evening may be strong to severe. Heavy rainfall 
will be a concern, as well.

The upper-level trough will move eastward with falling heights 
over the region Sunday afternoon through Monday morning. Several 
rounds of showers and thunderstorms are likely from late afternoon
through Monday night. A few of the storms may be strong and may 
produce locally heavy rainfall.


.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 644 PM CDT Tue Jun 25 2019

A couple of pockets of showers will affect INL and HYR initially,
then diminish by 01Z. Even with the showers, VFR is expected.
Elsewhere, a clearing trend is occurring with mainly a cumulus
field that is thinning out. An area of high pressure will be
nearby through the rest of the forecast with VFR. There is a low
probability of some BR overnight, but it will be patchy in nature.
Gusty surface winds are forecast by mid morning Wednesday.


Issued at 340 PM CDT Tue Jun 25 2019

Southwest winds will weaken this evening. Sustained winds of 10 
to 15 knots are expected, with occasional gusts to near 20 knots 
possible. A few thunderstorms will roll over the waters which may 
generate sporadic wind gusts of 25 to 30 knots. A few gusts to 35 
knots are not out of the question. Winds will remain below 20 
knots Wednesday into Thursday and will not pose a risk to small 


DLH  55  80  57  81 /  20  10  20  30 
INL  55  80  54  82 /  20  10  10  10 
BRD  56  84  60  85 /   0  10  30  30 
HYR  56  84  58  86 /  20  10  30  50 
ASX  55  82  57  82 /  30  10  30  40