Area Forecast Discussion
Issued by NWS Duluth, MN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

940
FXUS63 KDLH 291829 AAC
AFDDLH

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
129 PM CDT WED JUN 29 2016

.UPDATE...
Issued at 129 PM CDT Wed Jun 29 2016

Please see the new 18Z aviation discussion below.

UPDATE Issued at 1002 AM CDT Wed Jun 29 2016

Increased high temperatures today just a bit based on observation
trends and short-range guidance. Also updated the POPs/Weather to
introduce a sharper gradient for the afternoon showers and storms
expected across northeast Minnesota.

&&

.SHORT TERM...(Today through Thursday)
Issued at 336 AM CDT Wed Jun 29 2016

High pressure over the Midwest will shift south and east to the
southern Great Lakes region by this evening. Light westerly flow
will develop across the Northland in the wake of the departing
high pressure and ahead of an approaching cold front from the
north. While much of the Northland will have plenty of sunshine
today, there will be increasing instability across northeast
Minnesota today with the daytime heating, resulting in
scattered/broken cumulus and chances of pcpn across northeast
Minnesota. While the models indicate there could be up to several
hundred J/kg of mixed layer cape this afternoon and early this
evening, the threat of thunder will be limited by the lack of any
shortwaves or falling heights to provide extra synoptic lift.
Therefore, limited the thunder threat to only a slight chance of
thunder across the northern forecast area.

The cold front will move south through the Northland tonight and
Thursday, followed in the rear by an upper level trough Thursday.
Cool air will pour into the Northland, and the cold front will
bring about 30% to 50% chances of showers overnight and early
Thursday. Most of the models have very little most unstable cape
overnight, but kept a slight chance of thunder in case there is
enough frontogenesis near the cold front to help generate some
thunder. The showers will spread into northwest Wisconsin late
Thursday morning and Thursday afternoon, increasing in intensity
with the synoptic lift generated by the approaching upper level
trough. There will be an even better chance of thunder, compared
to today, for Thursday afternoon. The GFS and NAM indicate there
could be about 500 to 1250 J/kg of mixed layer cape across
northwest Wisconsin, but the threat of strong storms will be
limited by the lack of deep layer shear. The main threat should be
brief downpours with precipitable water values nearing 1.25
inches. This passing cold front will bring about a quarter inch of
rain for most of the northern and southeastern forecast area.

Highs will be in the middle to upper 70s today, and lows in the
middle to upper 50s tonight. Thursday`s highs will likely be later
in the day, compared to usual, because of the rain and lingering
cloud cover. Leaned on the 4 km NAM for cloud cover since it tends
to due well with cumulus in northerly flow situations, which
resulted in increasing cloud cover and delaying the clearing.
Highs on Thursday should range from the upper 60s to lower 70s.

.LONG TERM...(Thursday night through Tuesday)
Issued at 336 AM CDT Wed Jun 29 2016

A cold front and well amplified upper level trough in northwest
flow will move southward across the western Great Lakes region by
Thursday Night, bringing an end to precipitation chances for most
of the area Thursday Night. While we will remain in northwest flow
on Thursday Night and Friday, surface high pressure will bring dry
and cooler weather for the end of the work week. Friday looks to
be quiet with high temperatures in the lower 70s across the
region. Friday night will be a period of transition, as upper
level ridging to the west of our CWA will start to migrate into
the Northland. Return flow will not really develop until Saturday
and Saturday Night. The ECMWF and GFS both continue to hint at the
potential for MCS development Saturday Night and Sunday, sliding
along the International Border region in association with a low
pressure system and weak shortwave riding along the upper level
ridge Saturday Night and Sunday. Will continue to mention the
highest POP`s in the north during that period, but will have to
continue to watch for the potential for more organized storms and
MCS activity. ECMWF is most dramatic with the prognosis for an MCS
affecting the border region. Otherwise, general westerly flow is
expected to develop over the weekend and into the first part of
the upcoming work week. Relatively weak surface and upper level
features will likely continue to bring a chance of some
precipitation, especially diurnally driven, during the weekend and
early next week. Temperatures will generally be in the 70s, but
temperatures are expected to climb to around 80 or even into the
80s for next Tuesday and Wednesday. Lows will climb from the 40s
and 50s to the 50s and 60s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 129 PM CDT Wed Jun 29 2016

A cold front approaching from northwest Ontario and southern
Manitoba will result in scattered thunderstorms this afternoon
into this evening. Expect a period of thunderstorms at each
terminal, however timing is still a challenge. Elected to handle
the thunder potential with VCTS for the most part, except at INL
where TEMPO -TSRA expected before 30.00Z. VSBYS will likely lower
into MVFR category as storms pass overhead and think a period of
MVFR fog will follow the rain overnight. Also think thunder threat
will be short lived for any terminal, but rain showers will
persist for a longer period. Winds will veer northwest behind the
front, and will likely be gusty in thunderstorms. The front will
exit the area by late morning on Thursday, with affects at HYR
lingering nearly until the end of this TAF period. Overall
confidence in this forecast package is average.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  77  58  69  48 /  10  50  40   0
INL  78  56  67  45 /  80  80  10   0
BRD  79  59  73  49 /  10  40  30   0
HYR  77  57  72  48 /   0  50  80   0
ASX  78  58  70  49 /   0  60  70   0

&&

.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&

$$

UPDATE...Huyck
SHORT TERM...Grochocinski
LONG TERM...DAP
AVIATION...Huyck



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.