Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/16/20
Area Forecast Discussion
National Weather Service Duluth MN
538 PM CST Sun Nov 15 2020
.DISCUSSION...(This evening through Saturday)
Issued at 344 PM CST Sun Nov 15 2020
Snow is expected to end late this afternoon or evening with another
narrow band of snow expected for Monday, then a dry period. Strong
winds will gradually diminish late this evening and overnight.
Strong low pressure was just east of Lake Superior this afternoon
with gusty west/northwest winds and areas of light snow or
flurries in its wake. The gravity wave induced snow over Douglas
and Bayfield Counties has ended. Little additional snowfall is
expected this afternoon and evening so we cancelled the Winter
Weather Advisory for Iron County as well. Gusty west/northwest
winds will continue into the evening but will diminish overnight.
Low temperatures will be a challenge as some clearing will occur
but there are questions how long it will last before more clouds
move in ahead of the clipper for Monday. Where clearing does
occur, temperatures will quickly drop.
A quick moving clipper system will spread an area of snow across the
Northland on Monday. There is still considerable differences among
the models on where to put the snow with most of the hi-res models
north of the GFS/Canadian/ECMWF. Strong low level FGEN will
accompany the clipper and we expect a burst of 1 to 2 inches of
snow. We have the best chance from roughly Walker to the Twin Ports
to Phillips on south. This area may move a bit north or south but
we`ll have to wait longer to get a better handle on that.
After the clipper moves through Monday, a dry period is expected. An
upper ridge will build to the west with high pressure developing at
the surface. The upper ridge will flatten mid-week and warming
temperatures will occur Wednesday into Thursday. Highs Thursday will
be in the upper thirties to middle forties.
An area of low pressure is forecast to move into the southern
Wisconsin/northern Illinois region next Saturday tracking
northeast. Portions of the Northland will be affected by this low
and temperatures will be warm enough for a wintry mix.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 538 PM CST Sun Nov 15 2020
Strong low pressure is now well east of eastern Lake Superior in
Ontario this evening with strong west to northwest winds and MVFR
ceilings occurring in its wake. The back edge of the MVFR
ceilings were from far northwest Minnesota into south central
Minnesota but was progressing east at a decent clip. We used a
combination of the RAP and extrapolation to time the lifting of
the MVFR ceilings. The strong winds this evening will gradually
decrease overnight.
A fast moving clipper will move in late tonight and into Monday
bringing a narrow band of snow to portions of the Northland. MVFR or
IFR conditions will accompany the area snow. However, there is still
uncertainty regarding where the band will set up and for now we have
some MVFR vsbys but there will likely be a dip to IFR and later
updates will hopefully be able to pinpoint those locations and
times.
&&
.MARINE...
Issued at 344 PM CST Sun Nov 15 2020
Strong west to northwest winds will continue with gales of 35 to 40
knots well into the evening, decreasing late tonight. Strong low
pressure will continue to move away from the region and the gradient
will weaken late. Gale Warnings remain in effect and we will likely
need a Small Craft Advisory later tonight as the gales subside but
winds and waves remain elevated. Winds will decrease to 10 to around
15 knots by Monday afternoon but will increase again Monday night,
especially along the South Shore. Conditions will likely become
hazardous, mainly for small craft, overnight Monday and Small
Craft Advisories may be needed. West/northwest wind will subside
back to 10 to around 15 knots Tuesday with lighter winds Tuesday
night.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 18 30 15 30 / 10 60 0 0
INL 14 27 11 28 / 10 0 0 0
BRD 20 33 15 31 / 30 50 0 0
HYR 19 33 14 31 / 10 60 10 0
ASX 21 34 17 33 / 20 40 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Gale Warning until 2 AM CST Monday for LSZ121-140>148.
&&
$$
DISCUSSION...Melde
AVIATION...Melde
MARINE...Melde
Area Forecast Discussion
National Weather Service Des Moines IA
531 PM CST Sun Nov 15 2020
.DISCUSSION.../Tonight through Sunday/
Issued at 217 PM CST Sun Nov 15 2020
Synoptic Overview:
Short-wave trough axis that brought active weather on Saturday has
shifted east of the Mississippi River this morning, dragging the
deep surface cyclone over to the Great Lakes and associated cold
front has surged across most of the Midwest and is entering the Mid-
Atlantic region early this afternoon. Ridge axis currently sits
across the inner mountain west this morning but it working its way
eastward. There is another subtle short-wave moving through
Minnesota with a secondary cold front that is producing snow
showers, but is not expected to reach Iowa. The ridge working in
behind the exiting short-wave trough will drive pleasant weather
conditions considering that it is mid-November. Another PV anomaly
likely to move across the CONUS in the middle of next weekend.
Today and Tonight:
Even though the surface cold front has surged ahead, Iowa has
remained on the backside of the cyclonic flow early in the
afternoon, which left lingering cloud cover through 19z. However,
satellite has shown rapid clearing moving eastward across the
Missouri River Valley, depicting the area of subsidence associated
with the strong AVA over the Plains. By this evening, skies should
be completely clear. The winds have remained gusty for longer than
originally anticipated. Despite the end of the stronger CAA, RAP
soundings continue to show winds as high at 48 kts toward the top of
the mixed layer, and overall remain conducive to rather robust
momentum transport. As the cyclone moves further east through the
rest of the Great Lakes Region this afternoon, the pressure gradient
should weaken, and eventually so will the wind gusts. HREF mean
shows the bulk of the wind gusts greater than 30 kts moving east of
Iowa after 20-21z this afternoon. Looking at observations over east-
central Nebraska late this morning, wind gusts have reduced to less
than 30 kts at most sites. Thus, will not be expanding or extending
the Wind Advisory for counties in our forecast area. Neighboring
offices to the east may need to hold on to a Wind Advisory for a few
more hours. Looking at the secondary cold front and short-wave
impulse in Minnesota that produced snow showers NW of MSP, the
larger trough will begin to lift northeastward as the jet stream
rounds the base, thus will force it more eastward into Wisconsin and
prevent it from reaching the forecast area. For tonight, clearing
skies coupled with continued northwest flow will allow temperatures
to drop to the lower 20s northward with upper 20s south and
southeast. Model soundings overnight show boundary layer decoupling
and shallow inversion developing, which will inhibit any momentum
transport keeping conditions cool and calm. There does not appear to
be enough moisture for any widespread fog development, even with
strong radiational cooling.
Monday through Friday Afternoon:
As H5 ridge axis continues to move eastward through the Rockies, WAA
at H85 across the Front Range and High Plains will help to amplify
the pattern. For Monday and Tuesday in Iowa, the flow through H85
will still have a northerly component, but most model guidance does
not point to this promoting overly strong CAA. With clear skies,
there will be plenty of insolation, and thus temperatures should be
able to become quite comfortable during the afternoon. The strong
AVA regime will remain in place, and thus large scale subsidence
should help to develop strong surface high pressure across the
region Monday and Tuesday. After the ridge axis enters central
NE/KS, there is another trough/PV anomaly that begins to move across
the Rockies and slowly kicks off lee cyclogenesis. By Wednesday and
Thursday, the thermal ridge axis will be moving through Iowa, and
with the cyclone developing (or at least attempting to), surface to
H7 flow will turn southwesterly and promote stronger WAA underneath
the ridge. Thus, still expecting Wednesday and Thursday to be the
warmest days of this upcoming work week. With the flow increasing in
the western CONUS, this will begin to push the surface high pressure
eastward into the southern Great Lakes Region. On the backside of
the high pressure and with cyclogenesis in the Front Range / High
Plains vicinity, expect stronger gradient flow to create a setup for
breezy winds Wednesday and Thursday. With the lack of upper-level
support and lack of moisture transport, the forecast will remain dry
through most of this work week across the forecast area.
Next Weekend:
Early Friday, both GFS/ECMWF depict another short-wave ejecting out
of British Columbia quickly catching up with the weaker trough.
Eventually each trough axis catches up and phases to develop a
deeper trough, and will enhance deepening of the surface cyclone
over the Front Range / High Plains. Eventually this moves the
surface cyclone east across the Central Plains into the upper
Midwest. This shoots a warm front up to about the Hwy. 30 corridor
Friday night which will likely produce rain showers. Then as the mid-
level wave moves through it will push a cold front through on the
back side of the low pressure, adding additional precipitation
Saturday. This will mark another cool down for next weekend. There
is some discrepancy regarding the track of the cyclone and position
of the warm front, as some model solutions develop a closed H5 low
over the Four Corners Region next weekend. If that is to develop,
this would disrupt the southerly flow through the weekend, and would
change the positioning of the warm front moving through the region.
Regardless, it looks like there should be enough convergence and
moisture transport to support some kind of precipitation event next
weekend.
&&
.AVIATION.../For the 00Z TAFS through 00Z Monday evening/
Issued at 530 PM CST Sun Nov 15 2020
Main concern this period will be wind. Boundary layer decay has
allowed mixing to diminish and winds will remain generally 5 to
15kts prior to 05-06z. Upstream moisture starved wave will spread
narrow band of BKN150 across the region between 03-15z. Winds
again mix out as push of milder, followed by cooler air aloft
tracks southeast from 15z-23z...keeping winds generally WNW
15G25kts at all sites with KMCW seeing slightly higher gusts to
30kt. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Krull
AVIATION...REV
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
547 PM CST Sun Nov 15 2020
.SHORT TERM...(This evening through Monday night)
Issued at 328 PM CST Sun Nov 15 2020
Our days has been dominated by the deepening low moving through the
Great Lakes. We`ve been within the cyclonic flow of this low, which
has meant breezy northwest winds and ample cloud cover. Over the last
couple of hours, those wind gusts have settled under 45 mph (wind
advisory criteria), so we went ahead and ended our entire wind
advisory at 3 pm. The clearing is also starting to finally make
progress across western MN and should be east of our area by around
3z. This will result in clear skies for a bit tonight, but we`ll see
clouds increasing from the northwest as the shortwave currently over
southern Alberta dives southeast toward central MN.
That shortwave becomes our main issue for the short term, which is
where does a narrow band of snow (likely on the order of 1-2") end up
for Monday. There`s still a good deal of spread, with the 12z NAM
placing the band up through Duluth and the GFS putting it down from
roughly Mille Lacs over to Ladysmith. We see about a 50/50 split
between the northern and southern solution in the HREF, with the RAP
showing something similar to the NAM, with the ECMWF more, and even a
little further south of the GFS. For now, we followed close to the
Consshort consensus grids for PoPs, which favors the GFS solution.
Other change for Monday was to increase both highs and winds within
this clipper`s warm sector to the south of I-94 in MN. It looks
pretty sunny, with a well mixed boundary layer, may see a 50 come out
of Madison.
Monday night, just looks cold with skies clearing out and high
pressure moving in. NBM was pretty cold to begin with, so only did a
slight nudge down toward the cooler Canadian for lows, with fairly
widespread lows in the teens expected Tuesday morning.
.LONG TERM...(Tuesday through Sunday)
Issued at 328 PM CST Sun Nov 15 2020
Not much has changed in the long term. We see our northwest flow
switch to zonal or even WSW on Wednesday that lasts into the
weekend. This will result in near to above normal temperatures.
Precip wise, we still look to be waiting until next weekend for our
next shot at that.
In the wake of Monday`s clipper, Tuesday will be our one cold day of
the week, with strong WAA setting in Tuesday night into Wednesday.
Said warm air will be moving in during the day on Wednesday, with a
warm front looking to get to near I-94 by the afternoon. Main issue
this causes is with what our potential highs will be, with a pretty
good gradient in temperatures expected across our area on Tuesday,
with mid/upper 50s possible southwest of the MN river, with highs in
the low 40s out toward Ladysmith. Favored highs Wednesday toward the
ECMWF, which increased highs above the NBM south of I-94, while
leaving the NBM pretty much unchanged north of I-94.
After Wednesday, confidence decreases in the temperature forecast in
response to a weak front that will be sliding across the area
Wednesday night/Thursday. Models are still struggling with timing of
cold air into the area. This boundary will slowly sag to our south on
Friday and become the focus for a heavy band of precipitation over
the weekend. This precip looks to blossom on Saturday as a coupled
jet moves across the Plains, though ensemble and deterministic models
are starting to hone in on the heaviest precip falling from Iowa
into southern WI. This would put southern MN on the north end of this
deformation precip band. There was enough movement within the NBM
suite to see pops decrease across our area this weekend for all but
south central and southeast MN. Despite being on the north end of the
precip shield, it looks warm enough to keep the dominate p-type as
rain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 539 PM CST Sun Nov 15 2020
Back edge of clouds shows up nicely on IR satellite imagery, just
passing over KSTC and nearly at KMSP, such that have started those
two sites and points west within VFR. The 2 WI sites will remain in
MVFR for the first few hours of the 16/00z TAF set before going VFR
overnight. As a weak clipper system slides southeast over northern-
central MN into northern WI Monday, clouds will return mainly within
VFR levels. There is a small shot that KMSP and points east may have
ceilings drop into MVFR range so have advertised this for now but
would not be surprised if the models again are too aggressive with
lower ceilings in the latter hours of the TAF. Precipitation (-SN)
looks to remain north of all TAF sites so kept them dry. As for
winds, breezy W-NW winds this evening will diminish to 10kt or less
overnight through daybreak and swing back to southerly in advance of
this system. Winds will then veer to W and NW by late tomorrow and
again become breezy/gusty.
KMSP...Western edge of MVFR stratus deck is almost atop MSP so will
look for VFR conditions close to the start time of this TAF duration.
High confidence on any/all -SN to remain north of MSP Monday
afternoon. However, confidence not so great on the chances for MVFR
ceilings late Monday afternoon. Potentially may see those ceilings
raised to lower-level VFR but will see how the models evolve the
passage of the clipper system.
/OUTLOOK FOR KMSP/
Tue...VFR. Wind NW 5 kts.
Wed...VFR. Wind S 15-20G35 kts.
Thu...VFR. Wind NW 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
SHORT TERM...MPG
LONG TERM...MPG
AVIATION...JPC
Area Forecast Discussion
National Weather Service Marquette MI
700 PM EST Sun Nov 15 2020
.SHORT TERM...(This evening through Monday)
Issued at 409 PM EST SUN NOV 15 2020
Water vapor imagery and RAP analysis show a deepening negative-tilt
shortwave trough lifting ne through the Upper Great Lakes with a
vort max in the base of the trough lifting through Lower Mi. At the
sfc, the lowest pres is analyzed near the Soo at 980mb with the cold
front extending south through Lower Mi. Moderate to strong deep
layer forcing in response to the deepening shortwave trough
continues to support light to moderate snow over the west half with
light to moderate rain across the east half into early afternoon as
noted on webcams and sfc obs. Earlier report on Facebook of 3 inches
of snow at KIWD and continued snow occurring per webcams has
verified WW advisory for Gogebic County. Webcams also suggest maybe
two to three inches over the higher terrain of Ontonagon and
southern Houghton so there is hope these counties could verify the
advisory as well before deeper moisture and better forcing/lift
shift northeast with the exiting trough early this evening.
Winds so far have generally stayed blo advisory criteria even with
increased CAA behind the front to enhance mixing. W-NW gusts have
generally been 25-30 knots, except over the Keweenaw where they have
been 35-40 knots. Best alignment of the pres rise/fall couplet
(isallobaric wind) to the gradient wind to boost winds is still east
of the fcst area. That said, there could still be a boost to the
winds toward evening as both the RAP and NAM show around a 6 mb 3hr
pres rise max pushing across the area coinciding with a secondary
surge of CAA. Fcst soundings still suggest much of the area could
still tap into 40kt wind gusts, perhaps even close to 50 knot wind
gusts over the eastern Lake Superior shoreline so will keep the
advisory going into the evening. With the strong winds over the
water, building waves will lead to at least minor lakeshore
flooding/erosion issues on Lake Superior beaches, from Ontonagon to
Copper Harbor over the west, and from around Munising eastward will
be especially impacted as the highest waves pound the beaches there.
As mentioned before deeper moisture will depart the w early evening
and the e late evening. With that departure, steadier lake enhanced
snow will quickly diminish w to e. Otherwise, 850mb temps falling to
-10C to -12C will support some wnw flow LES. However, inversion
falling toward 3kft w will be a significant negative for LES as the
night wears on. Conditions will be a little more favorable over the
e as inversion falls to around 5kft. At this point, with the early
loss of deeper moisture out w, additional snow accumulations from
late afternoon into early evening should not be more than 1-2
inches. To the e, e of Munising that is, 1-2 inches are possible
before we lose enhancement later this evening. Min temps tonight
will be mostly in the 20s.
On Monday, cool w-wn flow will continue to support some lake clouds
downwind of Lake Superior. Inverted-V look to fcst soundings with
dry air beneath the inversion will severely limit additional LES
accumulations, however. Expect little if any accumulation west and
an inch or less to the east. Below normal max temps in the lower to
mid 30s are expected.
.LONG TERM...(Monday night through Sunday)
Issued at 325 PM EST SUN NOV 15 2020
On the hemispheric scale, a positive NAO and AO are expected to
continue through the end of the month, with the PNA trending
slightly negative to neutral through the same period. Troffing
currently over Upper Michigan now, is fcst to become more broad,
shifting slightly east over the greater Great Lakes and northeastern
regions. At the same time, amplified ridging over the N Pacific will
drive a trof downstream in the NE Pacific as a ridge develops across
the western CONUS. All in all, a fairly progressive, but amplified,
pattern is in store for Upper Michigan with a positive NAO/AO keeping
any persistent cold surges at bay for the time being. Look for
temperatures to begin near or blo normal, with a midweek warmup, and
then trending near normal as a transition to more zonal flow takes
hold towards the weekend.
On Monday night, Upper Michigan will be caught in NW flow between an
eastern CONUS trof and developing western CONUS ridge. This weekends
low pressure system will be pulled away towards James Bay as a
leeside high pressure will be sliding south along the Canadian
Rockies. This high pressure system will usher in drier air,
especially across the west half of the UP, with the east half of the
UP remaining just saturated enough for some LES. If it wasn`t so
dry, it would be the perfect LES set up for 36 to 48 hours of
continuous LES, but instead we`ll just get the clouds as this
pattern will hold through Wednesday morning. Ended up increasing
PoPs to chc with some added QPF from going fcst for this time period
across the east half in the NW wind LES belts. The best time for LES
potential appears to be after 9Z Tuesday through Tuesday afternoon,
slowly dwindling as inversion heights lower. Seems like 1 to 3
inches, with locally higher amounts should the Lake Nipigon
connection unfold like some models are suggesting, from Alger County
eastward Monday night through Wednesday morning.
On Wednesday morning, the western CONUS ridge will pushing into
western Upper Michigan as 850mb temps warm abv freezing through the
day. With a 45 to 55kt LLJ and SW WAA winds, could be a breezy
afternoon/evening in the SW wind downslope-favored areas. This WAA
continues right into Thursday as 850mb warm to 10C. Look for
Thursday to be the warmest day of the week, with highs near 50,
perhaps into the 50s should enough mixing occur.
A dry, weak cold front moves through Thursday afternoon, which looks
to bring 850mb temps back down 2C by Friday morning. On Friday,
expect continued CAA along a backdoor cold front as a shortwave
passes just to the north of Lake Superior. Left the PoPs out of the
fcst, but there could a few snow showers depending on the depth of
the wave as it passes through. The GEM suggests a little better
chance on Friday, as the EC and GFS keep things to the north through
Ontario.
Weak, zonal flow will bring the UP into the weekend as temperatures
remain near normal with 850mb temps remaining on either side of 0C.
Next chance for mentionable precipitation then comes Sunday into
Monday as GFS and EC show a leeside sfc low developing and moving
through the Great Lakes region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 657 PM EST SUN NOV 15 2020
Low level moisture wrapping around a deep low pressure system moving
toward James Bay will maintain MVFR cigs tonight. Any vsby
restriction with light snow at KCMX and KSAW will diminish and end
this evening. Expect conditions imrproving to VFR as drier air moves
in Monday. Strong northwest winds this evening with gusts to 30-40
knots will also diminish overnight.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 409 PM EST SUN NOV 15 2020
Main concern for Lake Superior is the strong w to nw winds that will
continue into tonight on the backside of a cold front/low pressure
system. Fcst still appears on track with high end gales over the w
half and storm force winds to 50 knots developing early evening over
the e. A few gusts could reach 55-60kt. Winds will diminish blo gale
force w late tonight. Storms over the e will diminish to gales late
tonight, then winds will fall blo gales by Mon aftn. Thereafter,
winds won`t diminish much as winds will likely hold in the 20-30kt
range thru Tue, strongest over the half of Lake Superior. High pres
ridge will arrive over Lake Superior late Tue night/Wed morning,
resulting in winds falling off to under 15kt for a time. Light winds
will be short-lived as the ridge departs and the next low tracks e
toward Hudson Bay. Southerly winds will ramp back up to 20-30kt
later Wed into early Thu. Strongest winds will be over the e half of
the lake where a period of 35-knot gales may be possible.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Wind Advisory until midnight EST /11 PM CST/ tonight for
MIZ001>007-012>014-084-085.
Lakeshore Flood Advisory until 7 AM EST Monday for MIZ001>003.
Wind Advisory until 6 PM CST this evening for MIZ009>011.
Lakeshore Flood Warning until 11 AM EST Monday for MIZ006-007.
Lake Superior...
Storm Warning until 1 AM EST Monday for LSZ249>251-266-267.
Gale Warning until 10 AM EST Monday for LSZ244-245-248-264-265.
Gale Warning until 7 AM EST /6 AM CST/ Monday for LSZ241>243-246-
247-263.
Gale Warning until 3 AM EST /2 AM CST/ Monday for LSZ162-240.
Lake Michigan...
Gale Warning until 4 AM EST Monday for LMZ221-248-250.
&&
$$
SHORT TERM...Voss
LONG TERM...JAW
AVIATION...JLB
MARINE...Voss