Scientific Forecaster Discussion
fxus63 kdlh 200310
Area forecast discussion
National Weather Service Duluth Minnesota
1010 PM CDT Sat Oct 19 2019
Short term...(this evening through Sunday night)
issued at 359 PM CDT Sat Oct 19 2019
A cold front has exited the Northland this afternoon and shortwave
ridging will develop overnight. Skies will clear over far eastern
areas late this afternoon and it will remain mostly clear tonight.
There may be some patchy fog tonight, especially over northwest
Wisconsin. The mostly clear skies and light winds will lead to lows
in the lower to mid thirties. An upper low will move into South
Dakota on Sunday and a surface low will be in nearly the same area.
Clouds wil be on the increase through the day with it becoming
mostly cloudy during the afternoon over western areas. We kept the
day dry as most guidance holds off on precipitation until the
evening and forecast soundings are quite dry below 700mb through.
00z Monday. We bumped highs up a bit for Sunday and have highs in
the upper fifties to lower sixties.
Long term...(monday through saturday)
issued at 359 PM CDT Sat Oct 19 2019
Main concern in the extended is widespread rain late on Sunday
through much of Tuesday. Expecting strong winds as the system lifts
north of the region late on Monday and Tuesday. Temperatures
trending downward as the week progresses.
A neutrally tilted trough will lift from the High Plains Sunday
evening into the upper Mississippi River valley and become
negatively tilted on Monday. As the surface low pressure will lift
from the High Plains into Minnesota. Models have slowed down a bit
on the onset of precipitation and have tried to reflect this by
slowing down precipitation chances Sunday night. Even though we are
only 36 to 54 hours out models still diverge a bit on the surface
low track. The NAM is an outlier with the low much further east than
the GFS, gefs, European model (ecmwf) and Gem. The gefs and GFS solutions are similar
with the low track a bit further north across northeast Minnesota,
while the European model (ecmwf) and Gem track the low along the Minnesota and Iowa
border. This will have implications for the Northland as a more
northerly track would likely bring the dry slot into the area which
would reduce precipitation totals. A more southerly track would
bring more precipitation to the region. At this point in time the
wpc super ensemble shows quantitative precipitation forecast values clustering roughly between 1 to
1.5 inches Sunday night through Tuesday. The system will lift over
the Northland through Monday into Ontario on Tuesday which will
gradually taper off precipitation Tuesday night from southwest to
northeast. It is during this timeframe where there is the best
chance for rain becoming snow, however no accumulation is expected.
There is some instability present Sunday night through Monday. This
will couple with strong qg forcing and may bring some isolated
thunderstorms to the region. Severe storms are not expected.
The other concern with this strong fall system is strong winds on
Monday and Tuesday. The tight pressure gradient over the region will
bring easterly winds early on Monday becoming northerly with speeds
of 5 to 15 mph and gusts of 15 to 25 mph by the afternoon. Winds
will become more westerly or northwesterly late on Monday into
Tuesday as the low lifts into Ontario. Expect sustained wind speeds
Monday night of 10 to 25 mph with gusts of 15 to 35 mph. Increased
wind speeds on Tuesday from the previous forecast with sustained
winds ranging from 15 to 25 mph. Gusts at this point in time are 20
to 35 mph. Several pieces of deterministic guidance suggest that
gusts may be around 45 mph per the GFS, NAM and European model (ecmwf). If models
continue to trend in this direction then a Wind Advisory may be
The low pressure system will continue rotating across northern
Ontario on Wednesday and Thursday. This will bring scattered rain
shower chances for much of the region due to the colder air
advecting in aloft combined with some daytime heating and cyclonic
flow over the region. Confidence lowers late in the week as model
significantly diverge in solutions. Low temperatures will be in the
mid 20s by late in the week. Highs will drop into the upper 30s and
mid 40s by Thursday and Friday.
Aviation...(for the 18z tafs through 18z Sunday afternoon)
issued at 1229 PM CDT Sat Oct 19 2019
VFR through the forecast with high pressure building in. High
confidence in breezy conditions this afternoon in wake of the cold
front per the GFS, NAM and rap guidance. Any gusty winds will
subside this evening as the mixed layer decouples and winds become
Confidence is low in the possibility of MVFR conditions at inl and
hyr. The NAM, GFS and rap hint at the MVFR stratus moving in from
southern Manitoba to inl. Not sure if this stratus will continue
to advance as the high builds in, but have hinted at the
possibility. Late tonight have medium confidence in radiation fog
development at hyr due to recent precipitation, clearing skies and
light winds. Most guidance does not show fog development, but the
arw and nmm do have LIFR fog developing east of hyr. Leaned on the
arw, nmm and past experience to at least hint at fog for hyr.
Any fog will lift by early Sunday morning as the mixed layer
grows. Winds will remain less than 10 knots with high pressure
sliding east of the region.
issued at 1009 PM CDT Sat Oct 19 2019
Fairly quiet as high pressure builds overhead. A strong system
approaches Monday morning and will likely bring strong small craft
winds and maybe even gales to the waters Monday.
Preliminary point temps/pops...
dlh 35 59 44 49 / 0 0 50 90
inl 36 58 43 49 / 0 0 50 80
brd 35 59 46 50 / 0 10 90 90
hyr 36 61 46 54 / 0 0 40 90
asx 36 60 44 55 / 0 0 30 90