Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/03/18
Area Forecast Discussion
National Weather Service Gaylord MI
1047 PM EST Fri Feb 2 2018
.UPDATE...
Issued at 958 PM EST Fri Feb 2 2018
A healthy lake effect snow band has been clipping the Whitefish Pt
area for a few hours since late afternoon, but that band is now
lifting just north of there. It will hover in that vicinity for
the next several hours, then get dragged back southward again as
winds veer. That won`t last long before 1000-850mb winds collapse
toward morning as the pressure gradient is disrupted, killing the
band entirely. Still, have bumped of snow amounts tonight north of
Paradise.
Elsewhere, very light lake effect snows are just starting to
respond to an influx of mid-level moisture. Areal coverage has
increased considerably near and north of M-32. Intensity is also
on an upward trajectory, though slower. QPF progs in far northern
lower MI from the hi-res guidance are generally unimpressive, less
than a tenth of an inch thru 12z. Might be able to slightly tweak
snow amounts down over far northern lower.
However, guidance is more bullish on breaking out snow showers in
the rest of nw lower MI overnight (especially near and s-sw of
TVC). Nam is probably excessive in breaking out almost 0.20 of
liquid near Wellston by late morning, but the HRRR and Rap both
argue for 1-2" snow accums even before the advisory kicks in down
there. Given that a headline is already up, there`s no good reason
not to accelerate the start time to cover late-night and early-
morning lake effect. Will go ahead and do that.
&&
.NEAR TERM...(Tonight through Saturday)
Issued at 307 PM EST Fri Feb 2 2018
...Lake snows give way to widespread snow to start the weekend...
High impact weather potential: Widespread accumulating snow likely
by the end of Saturday, heaviest in the traditional snow belt
regions.
Pattern synopsis/forecast: Broad troughing remains overhead, and
looks to remain locked in place for the next several days. Attendant
cold air drop within this trough axis continues to kick off lake
effect snow showers, albeit of lighter intensity than experienced
the last day or so as dry air and shallow lake induced convective
depths have taken their collective toll. Winds steadily backing
through the day have spread the wealth, so to speak, but once again
with minimal accumulations.
Attention through the near term focused on dual upstream waves, the
lead of which is punching rapidly southeast across northern
Minnesota, with the other way back across Alberta. Initial wave will
rejuvenate the lake processes tonight, while the latter looks to
drum up a widespread light to moderate snow event Saturday and
Saturday night.
Primary forecast concerns/challenges: Snow amounts and attendant
headline decisions remain the primary forecast concerns.
Details: One complicated forecast with regards to snow evolution (and
amounts) tonight and Saturday. Minnesota wave arrives quickly this
evening, bringing enhanced moisture along with it. While the lake
induced convective boundary layer remains fairly shallow, a
developing seeder-feeder mechanism in an increasingly favorable
thermal regime should support a reorganization and intensification
of lake snows. Wind speeds do decrease later tonight, which may
partially inhibit moisture flux off the big waters. Winds continue
to slowly back to a west/southwest direction, focusing best
enhancement along the Lake Michigan Coast and up into some of the
Tip of the Mitt counties. Still thinking an additional 2 to 4 inches
of snow tonight in those favored areas.
But...more snow to come Saturday with arrival of that second wave.
Initial shot of warm air advection gives way to transient fgen
forcing and broad deformation, all within a slowly deepening
moisture field (precipitable water values up near a quarter of an
inch). Still looking at a touch of lake enhancement in southwest
flow areas, although modifying thermal profiles and increasingly
disorganized wind fields likely preventing things from getting too
out of hand. System snow itself will deliver, especially across
northern lower Michigan. Expect an additional 1 to 4 inches,
heaviest closer to Lake Michigan. Isolated higher amounts are
possible, especially if fgen forcing can become stationary for any
length of time. Good news is wind speeds will remain light, negating
any blowing or drifting snow concerns. More snow expected Saturday
night. See short term section below for that information.
Headline Management: After in-house coordination with short term
forecaster and coordination with surrounding offices, have
introduced a winter weather advisory for much of northwest lower
Michigan, beginning tonight/Saturday morning, running into Sunday
morning. Possible more counties will need to be added at a later
time.
&&
.SHORT TERM...(Saturday night through Monday)
Issued at 307 PM EST Fri Feb 2 2018
...Snowy Weekend...
High Impact Weather Potential...Snow from a storm system and lake
enhancement/effect
Pattern Synopsis/Forecast...The ridge/Trough pattern at 500 mb has
returned over the Upper Great Lakes, and expected to continue over
the region through the next weekend. So the details over the weekend
will be that of the sfc low/500 mb shortwave trough rotating through
the region producing light to moderate amounts of snow for Saturday
night, then lake effect snow Sunday and into Sunday night. Monday
has lake effect, but from the SW and starts as lake effect, but
begins to transition into system snow into Monday.
Primary Forecast concerns...The system snow is pretty straight
forward, so the amounts look okay. Had to blend the snow ratios(SLR)
a bit with the WPC guidance for SLR, as the model consensus numbers
were a bit on the high side for the system snow. Then transitioned
into the 20+:1 rations Sunday as we get into the LES with the colder
850 temperatures (-18c to -20c). Monday, SREF and GFS show WSW flow
snow les, but the 850 mb temperatures support it, but the 850-700 mb
layer rh is a bit on the dry side. so would expect minor to light
amounts.
.LONG TERM...(Monday night through Friday)
Issued at 307 PM EST Fri Feb 2 2018
...Continued Below Normal Temperatures and Periodic Snow...
Extended (Monday night through Friday)...As mentioned in the pattern
section of the short term section above, the 500 mb low stays north
of the forecast area, and keeps us in the trough into next weekend.
This will bring us below normal temperatures, and periodic chances
of snow/snow showers as a low will move through and bring system
snow, then on the back side, lake effect snow showers until the high
dries out of the region briefly for it to start over again.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1047 PM EST Fri Feb 2 2018
Snow to intensify late tonight into Saturday.
Mostly VFR with some MVFR conditions out there presently (mainly
PLN), with light lake effect snow showers. An incoming low
pressure system will reach southern WI by Saturday evening. System
snow and lake effect will to be re-invigorated late tonight and
especially Saturday. IFR conditions will arrive at MBL/TVC/PLN on
Sat morning, and APN in the afternoon.
Current west winds will back southerly tonight and Saturday.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY from 4 AM Saturday to 9 AM EST Sunday
for MIZ020-025>027-031>033.
WINTER WEATHER ADVISORY until 7 AM EST Sunday for MIZ016-017-019-
021-022.
&&
$$
UPDATE...JZ
NEAR TERM...MB
SHORT TERM...JL
LONG TERM...JL
AVIATION...JZ
Area Forecast Discussion
National Weather Service Cheyenne WY
339 PM MST Fri Feb 2 2018
.SHORT TERM...(This evening through Saturday night)
Issued at 235 PM MST Fri Feb 2 2018
Main focus will be on winds in the wind prone areas as well as the
expected heavy snowfall over the higher mtns through Saturday.
Winds around the Arlington area as well as the summit have edged
up this afternoon and a couple locations hitting high wind speeds.
Expect this trend to continue while spreading a little more so
have upgraded the watch to a warning. Winds still look like they
will ease some tomorrow morning before likely rising again by late
in the day as 7H winds increase to around 50kts along with decent
downward motion over the S. Laramie Range. Will also have to watch
areas such as the Laramie Valley for some stronger winds if
sufficient mixing occurs. Moist nwly flow will keep snow going
over the higher mtns through Saturday night, likely heaviest later
this evening into Saturday, aided by a passing shortwave in the
flow. Next push of cold air arrives Saturday night with an areas
of mainly light snow developing behind the front over the
northeast part of the CWA.
.LONG TERM...(Sunday night through Friday)
Issued at 235 PM MST Fri Feb 2 2018
A general northwest flow aloft will keep the varying weather going
across the area with periodic cold air surges and associated
snows. Fairly widespread snow expected over the CWA early Sunday
as the front banks up against the mtns but the snow should end
fairly quickly Sunday afternoon as the surface high dives rather
quickly southeast over the central plains and upslope flow is
lost. Could be a band of moderate snowfall over the northern parts
of the CWA Sunday morning so will have to watch. Front quickly
backs out Sunday night with a strong wind event shaping up again
for the wind prone areas into Monday morning. The next surge of
colder air then arrives late Monday with another round of mainly
light snow behind it. Cool Tuesday before warming again for Weds
and Thursday. Unsettled pattern persists for late in the week as
the next surge of cold air drops out of Canada into the region
Friday bringing the next chance for snow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 337 PM MST Fri Feb 2 2018
VFR conditions for airports east of Laramie Range the next 24
hours. Looking at some snow to develop west of the Laramie Range
tonight that could impact KLAR and KRWL with lower flight
conditions for a time tonight. Latest HRRR hitting KRWL the
hardest with IFR conditions after 08Z. Generally followed its
guidance for the 00Z TAFs.
&&
.FIRE WEATHER...
Issued at 235 PM MST Fri Feb 2 2018
No fire weather concerns expected into at least early next week.
There will be periods of gusty/strong winds but cool temperatures
and resulting RH well outside of critical thresholds.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Storm Warning until noon MST Sunday for WYZ112-114.
High Wind Warning until 5 AM MST Saturday for WYZ110-116.
High Wind Warning from 8 PM this evening to 5 AM MST Saturday
for WYZ106-117.
NE...None.
&&
$$
SHORT TERM...RE
LONG TERM...RE
AVIATION...GCC
FIRE WEATHER...RE
Area Forecast Discussion
National Weather Service Grand Forks ND
704 PM CST Fri Feb 2 2018
.UPDATE...
Issued at 658 PM CST Fri Feb 2 2018
Light snow area moving SSE into Grand Forks/Thief River falls and
will move into Bemidji soon. Nothing impactful with trace to a
couple tenths. Will keep a mention of -sn thru the evening in NE
ND and NW MN. Next stronger system moving quickly southeast into
eastern Washington state at 00z and will move southeast into the
central Plains into Saturday. Sfc low with this feature will
develop in Montana and move into southern South dakota or northern
Nebraska. Light snow in Alberta and SW Saskatchewan will spread
ESE thru the night across ND and parts of SD reaching E ND 06z and
afterwards into NW/WC MN and ending Saturday morning. HRRR and RAP
meso models have shifted a bit back southward with main snow and
show best chances for 3 or so inches more from south of Minot to
Fargo area... But a wide area of light snow so idea of a 1-3 inch
snowfall still seems ok...but it is possible many spots in NE ND
are on the lower end of current fcst range (2-3). Winds do
increase Saturday from the north at 15-20 kts in cold advection
and this will need monitoring. But appears winds to follow after
the snow ends.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 312 PM CST Fri Feb 2 2018
Snow and associated impacts the main concern for the forecast
overnight into Saturday. Northwest flow afoft continues to bring
embedded short waves across the northern plains. There is a
current wave bringing light snow to the Roseau and Lake of the
Woods area. The light snow will drift to the south into the
late afternoon and evening. Minimal impacts with this event as an
inch or so of accumulation is expected from light snow over
several hours.
Attention turns to the next wave into the overnight period as SFC
low tracks from NW SD to SE SD during Saturday. As it moves
southeast early Saturday morning snow will spread from northwest
to southeast across the area with Pwats increasing to near a
quarter inch. Frontogentical forcing translates quickly across the
forecast area with strongest synoptic forcing displaced north
across Manitoba. Expecting some disorganized and transient bands
developing and diminishing through the overnight. Given this
environment expecting widespread 1 to 3 inches with possibly 4
plus inches if and where a stronger band sets up. Winds will turn
towards the north and escort the next push of arctic air into the
region Saturday afternoon. Blowing snow is not anticipated as
winds remain below 20kts however some drifting snow can be
expected Saturday afternoon.
.LONG TERM...(Saturday night through Friday)
Issued at 312 PM CST Fri Feb 2 2018
Main concern to start the period will be temperatures and
associated wind chills. Surface ridging will build into the region
overnight allowing temperatures to drop into the teens and
twenties below zero. Although winds won`t increase until later in
the day on Sunday, temperatures will be cold enough to produce
wind chills within advisory criteria (possibly pushing warning
criteria across the far north). The dangerous wind chills will
continue throughout the day on Sunday (even as temperatures warm)
due to increasing westerly winds between high pressure to the
south and low pressure further north. Sunday also has the
potential to bring blowing snow and associated visibility issues
if winds can get high enough (roughly 30+ mph) thanks to any fresh
snow from Saturday.
Following the weekend, cold high pressure looks to keep the region
dry for the first part of the new work week. However, wind chills
will continue to be a concern during the overnight and early morning
hours for much of the area. Confidence remains low for any
precipitation chances later in the period as model solutions
diverge.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 658 PM CST Fri Feb 2 2018
Mix of MVFR/VFR cigs thru the pd...mostly in the 2500-4000 ft agl
range. Winds turning northerly overnight into Saturday and light
snow at times this eve GFK/TVF/BJI then more widespread and lower
vsbys late tonight into Saturday morning.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Riddle
SHORT TERM...JK
LONG TERM...Lee
AVIATION...Riddle
Area Forecast Discussion
National Weather Service Glasgow MT
647 PM MST Fri Feb 2 2018
.DISCUSSION...
630PM Update...With snow beginning to move into northeast Montana
from the west and north this evening, the overall forecast looks
to be in excellent shape. Only real change was to increase pops in
the northeast a little earlier than previously forecast as snow
is already being shown on radar across northern Valley county all
the way east to Sheridan, and have also received reports of snow
from Poplar. This snow is expected to increase in coverage
throughout the evening, but should remain fairly light in
intensity. Most of northeast Montana can expect 1 to 2 inches of
snow tonight, then another round Saturday. This second round will
be more intense across the western half of northeast Montana, with
3 to 6 inches of snow possible, and up to 8 inches would not be
surprising in the Little Rockies.
Of immediate concern is also the freezing rain/sleet
potential. Latest near term models are very consistent with at
least the possibility of freezing rain generally along a frontal
boundary that will move across Petroleum and Garfield counties
tonight with H850 temperatures up to 2 or 3 degrees Celsius above
zero, and below freezing temperatures at the surface. This is
also supported by the 1000 to 500mb geopotential thicknesses. With
the SREF and RAP bringing above freezing temperatures aloft as
far east as Prairie County, have no issues with leaving the Winter
Weather Advisory as is. With the H700 and surface temperatures
well below freezing, however, there is question as to how long
this lasts with such a shallow warm layer to work with, so expect
this to be limited to along or very near the frontal boundary.
With recent reports of freezing rain in Havre and the potential
impacts to roads and sidewalks any freezing rain would have,
prefer to err on the side of caution and make no changes. Will
keep an eye on things to see if we end up needing to expand the
area of freezing rain in the forecast.
Behind this system, another shot of cold air moves in tomorrow
night. Will likely need either a Wind Chill Advisory or expand the Winter
Weather Advisory for bitter cold wind chills Saturday night into
Sunday, but will leave this for the overnight shift to take
another look at and make that final decision.
Previous Discussion:
As a wave of pacific moisture overrides Arctic air residing into
northeast Montana, expect light snow at times tonight. Latest 12z
model guidance does have the warm nose aloft a little further
northeast. Taking a look at Bufkit forecast soundings across the
area as well as SREF probability of precipitation type products,
the Winter Weather Advisory in effect looks good. Given the trend,
the next shift will have to monitor locations a little further
north and east.
A transition to snow will take place Saturday and continue into
Saturday night. Several inches of accumulation are likely, and
this will create travel difficulties, especially if it obscures
any icy surfaces that develop. For messaging simplicity, left the
Winter Storm Watch in place for now, and the next shift can make
any upgrade decisions as the existing advisory reaches expiration.
Lastly, with a reinforcement of Arctic temperatures Saturday night
and Sunday morning, wind chill concerns may result at times as
well, and this will be another cause of impacts.
Expecting northwest upper flow over the region for Sunday into
early next week. The next wave of overrunning moisture looks to
affect the southwest zones during this time with accumulating snow
again possible.
Given the focus on the near term impacts as well as considering
how model spread increases at larger time scales, the forecast for
the midweek onward was trended toward latest model consensus
blends which maintains an unsettled weather pattern overall
through the week. Maliawco
&&
.AVIATION...
IFR CIGS will prevail along with reduced visibilities in snow
overnight and on Saturday. A little wintry mix is possible at
times tonight as well near KGDV, though confidence is low on the
northeastward extent. Expect northeast winds at 5 to 10 kts
becoming north on Saturday at 10 to 15 kts. Maliawco / Hickford
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from 3 AM MST Saturday through late Saturday
night for Central and Southeast Phillips...Central and Southern
Valley...Daniels...Dawson...Garfield...McCone...Northern
Phillips...Northern Valley...Petroleum...Prairie...Richland...
Southwest Phillips...Western Roosevelt...Wibaux.
Winter Weather Advisory until 3 AM MST Saturday for Garfield...
Petroleum...Prairie...Southwest Phillips.
&&
$$
weather.gov/glasgow
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
720 PM EST Fri Feb 2 2018
.UPDATE...
Issued at 720 PM EST FRI FEB 2 2018
Surface high pressure is currently centered over the lower OH
Valley region. At the same time mid level heights are expected to
rise tonight with the sfc high working across the Appalachians
with the center of the high over eastern VA and northeast NC by
dawn on Saturday. Cu and stratocu have been dissipating with loss
of sunlight with any remaining low clouds dissipating over the
next few hours. Mid and high clouds will increase overnight,
especially late. However, with dewpoints across the region near
10 above and many valley locations in the mid to upper teens the
cold spots should easily reach 8 or 9 above overnight. Some
ridgetop locations were also running colder than the previous
forecast and some of the guidance so those locations were also
cooled off a bit as well. Hourly temperatures have been updated
accordingly with no other changes attm.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 330 PM EST FRI FEB 2 2018
20z sfc analysis shows high pressure moving steadily into Kentucky
as low pressure and cyclonic low level flow departs southeast
Kentucky. The low has held on fierce today, though, keeping lower
clouds in the southeast along with some scattered light snow
showers and flurries into the first part of the afternoon. Only
now are the clouds clearing and the radar returns fading out.
Temperatures did not recover much today from morning lows as
northwest winds of 5 to 15 mph continued to advect in colder air.
As such, afternoon highs were generally capped in the upper teens
and lower 20s. Meanwhile dewpoints were mainly in the single
digits.
The models are in good agreement aloft through the short term
portion of the forecast. They all depict a pattern adjustment in
the wake of an eastern trough pulling out of the area switching
mid level flow from northwesterly tonight to southwest flow on
Saturday into Sunday morning. Embedded in this flow will be a
developing trough and associated spokes of energy moving into
Kentucky from the west Saturday night. At the same time a couple
strengthening 300 mb jet streaks will interact over eastern
Kentucky with a healthy pocket of divergence aloft and enhanced
lift for our area late Saturday night. Given the model symmetry
will favor a general blend, but lean most heavily on the higher
resolution HRRR and NAM12 for weather specifics through the
period.
Sensible weather will feature a clear and cold night with good
radiation expected owing to light winds and subsidence aloft.
Further complicating the situation will be the disparate, and
almost entirely elevation dependent, snow cover left from last
night`s event. Expect the ridges to be the coldest due to the
extra snow cover, but valleys should not do too bad either so have
lowered min temperatures across the board tonight. For Saturday
we will see quite a warm up as the winds switch to the south and
increase ahead of an incoming warm front. This front brings
another slug of moisture to eastern Kentucky later that night into
Sunday morning with a dicey temperature profile. Best indications
are that the pcpn will initially wetbulb to below freezing
through the column resulting in a period of snow - perhaps mixed
with a touch of sleet for a time late Saturday night into dawn
Sunday. Generally, a half to one inch of snowfall can be expected
from this. Will highlight this concern in the forthcoming HWO.
Again used the CONSShort and ShortBlend as the starting point for
all the grids with some complicated point based adjustments
tonight for elevation and snow cover differences. As for PoPs,
kept them low through 06z Sunday before ramping them up toward
12z.
.LONG TERM...(Sunday through Friday)
Issued at 255 PM EST FRI FEB 2 2018
The extended period will feature alternating periods of quiet and
active weather across eastern Kentucky. The start of the period will
feature periods of rain and snow showers across the area Sunday
through Monday morning, as areas of low pressure moves slowly across
the Great Lakes and Ohio Valley regions and the Tennessee Valley. A
mix of rain and snow can be expected for most of the area on Sunday
morning, with our far eastern Kentucky seeing all snow to start the
day. The snow and rain snow mix should transition to all rain
through out the mid and late morning hours, with everyone likely
seeing nothing but rain by early Sunday afternoon. Snowfall amounts
should average less than an inch for most locations, with the higher
terrain along the Virginia perhaps seeing an inch or two of snow
before all is said and done. After the precipitation finally comes
to an end on Monday, we can expect a brief period of dry weather
Monday afternoon and most of Monday night.
Another area of low pressure, and its attendant surface cold front,
area forecast to move across the region from early Tuesday morning
through early Wednesday night. This system should bring scattered
rain and snow showers to the area Tuesday morning, before
temperatures warm enough for everything to transition over to all
rain by early Tuesday afternoon. This system will not have the
amount of cold air with it that its predecessors had, so only a rain
snow mix is forecast for Tuesday night into Wednesday morning north
of the Mountain Parkway. After a period of nothing but rain, it
looks like another bit of cold air will make its way into the area,
which will pave the way for snow mixing with rain by late Wednesday
afternoon. This trend should then continue into Wednesday evening
and Wednesday night, with a rain snow mix changing over to all snow
across the area. This last bit of precipitation should be out of the
area by late Wednesday night. Thursday and Friday should be dry, as
a ridge of high pressure finally builds across the region.
Temperatures on average should max out each day in the 40s, with the
exceptions being Monday, when highs will likely not make it out of
the 30s, and Tuesday, when locations along and south of the Hal
Rogers Parkway may max out in the lower 50s. Areas north of the
Mountain Parkway also may only make it into the upper 30s for highs,
with lower 40s everywhere else on Thursday. Nightly lows should
generally be in the 20s across the area. Tuesday night will be the
outlier, with lows that night forecast to only fall into the 30s and
40s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 719 PM EST FRI FEB 2 2018
VFR conditions are occurring across the region with a few patches
of stratocu around 2kft lingering over far southeast KY near the
VA border. These should continue to dissipate through 3Z as
surface and mid level ridging build across the area. The high will
move east of the area later tonight and on Saturday with mid and
high clouds gradually increasing and lowering from west to east
between ahead of the next approaching system. Winds will be light
and variable through tonight as the high moves across the area,
becoming southerly at generally 10kt or less during the 12Z to 0Z
period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...JP