Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 191713
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1213 PM CDT Fri May 19 2017

.UPDATE...
Issued at 605 AM CDT Fri May 19 2017

Temperatures are beginning to warm above freezing and have dropped
the headlines. Beefed up the cloud cover early this morning for
the cirrus shield that persists. Should see some erosion of the
cirrus later today. Rest of the forecast on track.

&&

.SHORT TERM...(Today through Saturday)
Issued at 328 AM CDT Fri May 19 2017

High pressure covered the forecast area at 07Z with a light and
variable wind. A large shield of thick cirrus was moving into the
region from the south. This is ahead of the system due to affect the
area on Saturday. Temps vary wildly at 07Z with upper 20s to upper
30s along and north of the Iron Range, upper 20s to lower 30s in
northwest Wisconsin, and upper 30s to lower 40s in the southwest
corner of the forecast area. As the cirrus overspreads the rest of
the region over the next few hours, will see a limit to additional
radiational cooling. Frost/freeze headlines will have worked out.

The surface high will drift over the Great Lakes tonight. Minimum
temps will be warmer tonight with weak warm air advection underway,
and a bit more cloud cover expected. No frost is forecast. Model
differences begin late tonight with the onset of the rain associated
with the system due to affect the region through the weekend. The
NAM/GEM are rain free. The GFS suffers from gridscale feedback which
produces some QPF over the Brainerd Lakes after 09Z. The ECMWF is
the wettest and furthest north with its QPF by 12Z Saturday, covering
the southern counties of the forecast area. Used a compromise which
led to small pops over the southern counties after 09Z.

A closed upper low will drift to near Sioux Falls on Saturday. This
results in rain gradually increasing in coverage across the region.
Models disagree on the amount of QPF to affect the area. Regardless,
some periods of moderate to heavy rain showers will occur,
especially in the afternoon as PWATS increase to near one inch. No
thunder expected as best instability stays south of the forecast
area. This is confirmed by all models. Used a blend for pops/QPF.

.LONG TERM...(Saturday night through Thursday)
Issued at 328 AM CDT Fri May 19 2017

The models forecast a surface low pressure center somewhere from
southern Minnesota to northeast Iowa, depending on the model,
Saturday evening. They all then track it north-northeast into
Ontario Sunday night. Rain will be likely with this low pressure
system. An upper level trough will then remain over the region into
early next week with continued chances for showers over parts of the
area. An upper level ridge will build over the western CONUS into
next week with a northerly upper level flow over the Northland by
mid week. A few shortwaves will move south over the area providing
more chances for rain.

Rain will be likely Saturday night into Sunday with coverage
decreasing Sunday afternoon into Sunday night. Storm total rainfall
from Saturday through Sunday will range from a half inch to around
an inch. There will be a chance for thunderstorms over mainly
northwest Wisconsin Saturday night which could lead to some locally
higher amounts. Highs Sunday will only be in the upper forties to
lower fifties.

The low will be slow to move away from the region due to downstream
ridging. A couple more shortwaves will move around the upper low
into Tuesday with chances for more showers over parts of the
Northland. The GFS does have a stronger shortwave Monday night into
Tuesday and as a result has more QPF than the ECMWF. At this time
though, the track would favor areas just south of the Northland with
the higher rainfall. High temperatures will warm to the lower
fifties to mid sixties across the Northland Monday, then cool a bit
Tuesday.

A weak high will quickly move through the area Tuesday night into
Wednesday before yet another shortwave brings a chance for showers
into Thursday. Thursday`s high will be the warmest of the week so
far, with highs in the sixties. It will be cooler around Lake
Superior.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1213 PM CDT Fri May 19 2017

VFR conditions will prevail through the TAF periods at all sites.
Increasing VFR clouds from the south today into tonight with
ceilings falling to around 10kft AGL overnight, then lower but
likely remaining VFR at BRD/DLH/HYR through Saturday morning. Rain
and MVFR ceilings are possible towards the end of the TAF period
at 18z at these sites, with off and on rain expected through the
afternoon Saturday. Light winds out of the east today and
tonight, increasing tomorrow with gusts to 15-20 knots possible
Saturday morning at most sites.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  51  37  45  38 /   0   0  80  70
INL  60  38  56  39 /   0   0  50  70
BRD  57  40  48  40 /   0  10  80  60
HYR  57  39  51  43 /   0   0  80  70
ASX  50  35  47  39 /   0   0  80  70

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&

$$

UPDATE...GSF
SHORT TERM...GSF
LONG TERM...Melde
AVIATION...JJM



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