FXUS63 KDLH 182108

Area Forecast Discussion
National Weather Service Duluth MN
408 PM CDT Mon Mar 18 2019

.SHORT TERM...(This evening through Tuesday)
Issued at 408 PM CDT Mon Mar 18 2019

Relatively quiet conditions were found across the Northland this
afternoon. Diurnal Cu developed over the Arrowhead and much of
northwest Wisconsin. Moisture depth appears limited and expect
there are few, if any, snowflakes or raindrops reaching the
ground. Cloud cover will gradually increase from the northwest
tonight as a shortwave trough moves through the area. Models have
been struggling with the sky cover all day and I think the
consensus blend is too pessimistic. In collaboration with
neighboring offices, I’ve decreased sky cover below guidance,
but not by much. Temperatures were able to cool considerably last
night, even with the presence of thin overcast. Have lowered temps
toward the cooler side of the bias-corrected guidance tonight
with lows in the low teens to low 20s.

Tuesday looks dry at this time as there will be a brief period of
ridging before the next shortwave trough arrives Tuesday evening.
There are concerns about dry air below cloud layer with the
second trough. Have lowered POPs in consideration of the dry air
near the surface. Have brought slight chance POPs southeastward
from our northern zones into the Arrowhead and eventually
northwest Wisconsin Tuesday night. Portions of central Minnesota
should remain dry as the best forcing will be located farther
east. Highs on Tuesday will reach the middle 40s in northwest
Wisconsin and the upper 30s and low 40s in Minnesota. Lows Tuesday
night will be in the low to upper 20s.

.LONG TERM...(Tuesday night through Monday)
Issued at 408 PM CDT Mon Mar 18 2019

Wednesday morning we may have some lingering snow/rain showers in
the morning as the shortwave from Tuesday night finishes moving
through the area. Low level dry air moving in behind this wave
should keep any diurnally driven afternoon cumulus from producing
any showers, but cloud cover should stay relatively high as a

Wednesday night through Saturday will be quiet, with a a gradual
warming trend. On Wednesday night, a shortwave will drop through
the northwest flow aloft, but should not affect the forecast area
with more than some cloud cover, as the most potent part of the
shortwave stays east of the forecast area. Behind that wave,
ridging at both the surface and aloft builds in over the forecast
area for Thursday through Saturday, and while a weak, fast moving
shortwave dives through the flow across the area Thursday night,
it also looks too far east to bring showers to the area.

Sunday and Monday there are some significant differences in the
forecast between the models. In the Wednesday-Thursday time range
an upper low moves onto the southwest CONUS, and since at this
point it is already cut off from the northern stream flow, it
slowly meanders east across the Rockies Friday and Saturday before
shifting far enough east to affect the central CONUS late on the
weekend and early next week. The models differ in how far south
the upper features slide, and how much ridging stays in place over
the forecast area. This results in the farther north GFS bringing
a two day period of rain chances to the forecast area, with the
more southerly ECMWF and CMC keeping us dry. For now have left the
consensus chance pops in the forecast, and we will have to see
how the trends evolve before pinning this event down. Personally I
suspect the GFS is far too wet, but we should get at least a
small chance of precipitation sometime in that time range.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 107 PM CDT Mon Mar 18 2019

A cumulus field over the area as of issuance time has produced
primarily VFR conditions, though a few sites are reporting MVFR
ceilings with rain/snow showers, which should be temporary in
nature. This cumulus field should dissipate or become all VFR by
22Z. A front will move through the area after 00Z, bringing an
area of initially VFR clouds that slowly deteriorate to MVFR with
a small chance of showers for KINL and KHIB after 06Z. The MVFR
ceilings should become scattered and return to VFR between 13Z
and 17Z.


DLH 21 41 26 42 / 10 0 20 10
INL 22 40 27 42 / 20 10 20 10
BRD 18 40 24 42 / 10 0 10 10
HYR 17 44 26 43 / 0 0 20 20
ASX 20 45 27 44 / 10 0 20 20




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