Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/18/19
Area Forecast Discussion
National Weather Service Bismarck ND
854 PM CST Sun Feb 17 2019
.UPDATE...
Issued at 834 PM CST Sun Feb 17 2019
The main forecast issue tonight will be temperatures. At the
surface, cold high pressure from the southern prairie provinces of
Canada, into eastern Montana will move slowly southeast over the
forecast area tonight with a general area of high pressure
settling over the state during the day Monday. We still currently
have a weak inverted trough into western ND, along with the
remnants of a weak circulation aloft. Satellite continues to show
abundant mid and high level clouds lingering over western and
central ND. Forecast Bufkit soundings show the moisture going
nowhere particularly fast, with mid and high level moisture
increasing across the north late. Our current forecast
temperatures are dropping too fast considering the amount of
clouds remaining over the area. We utilized a blend of time lagged
HRRR temperatures with the previous forecast temperatures to get a
start on raising minimum temperatures tonight. This brought
everyone up 2-6 degrees. If clouds continue to hang on, think we
may need to visit temps again. However with the cold high dropping
south, didn`t want to get to ambitious as any clearing will allow
temperatures to drop quickly. With the change to temperatures, the
potential for wind chill headlines has lowered. Updated text
products will be sent shortly.
UPDATE Issued at 517 PM CST Sun Feb 17 2019
Late Sunday afternoon, an inverted trough remains situated from
central plains surface low into western ND, with weak mid level
circulation over the western Dakotas. Thus light snow continues
over far southwest ND. Expect little if any accumulation, but did
bump up pops through the early evening.
Otherwise no significant changes to the going forecast. Updated
text products will be sent shortly.
UPDATE Issued at 220 PM CST Sun Feb 17 2019
Visibilities continue to improve across southwest North Dakota as
snow continues to become lighter and diminish. Very little to no
additional snowfall accumulations are expected. Therefore, the
remaining Winter Storm Warnings across Golden Valley, Billings,
Slope, and Bowman counties have been cancelled.
&&
.SHORT TERM...(This evening through Monday)
Issued at 1244 PM CST Sun Feb 17 2019
Light snow lingers across far southwest North Dakota this evening
and into tomorrow morning.
Current surface weather analysis shows an inverted surface
pressure trough across western North Dakota. This has helped
provide enough lift for light snow to continue this afternoon
across parts of western North Dakota. The 12z iterations of the
GFS/NAM/EURO keep this surface pressure trough nearly stationary
through 06z this evening, before high pressure builds in later
tonight.
The time-lagged HRRR was used for the probability of precipitation
forecast through Monday morning since this model guidance matches
the current observations very well. This model depicts the
continuation of light snow across far southwest North Dakota
tonight, before winding down tomorrow morning. Up to one inch of
additional snow looks likely. Blowing snow will not be a concern
this evening or tonight as winds look to be too light.
A surface high will dominate North Dakota tomorrow, leading to
quiet weather. Skies look to remain mostly cloudy due to an
impulse aloft with enough moisture. The latest blend of model
guidance keeps temperatures cold, with highs in the single digits
above zero. Wind chills to 25 below zero will be likely tomorrow
morning.
.LONG TERM...(Monday night through Sunday)
Issued at 1244 PM CST Sun Feb 17 2019
Below average temperatures highlight the long term forecast.
Western and central North Dakota should be dry Monday night
through Tuesday afternoon as the center of Monday`s surface high
moves southeast into the Great Lakes region and flow aloft stays
nearly zonal. The main concern will be very cold wind chills
Monday night through Tuesday morning, with the latest blend of
model guidance suggesting wind chills to 30 below zero. There is
still some uncertainty regarding the expected cloud cover
conditions Monday night. If guidance starts to trend towards
clearer skies, then temperatures will likely get colder than what
is currently being forecast.
A developing upper level low and associated surface low will bring
a chance of snow to southeast North Dakota Tuesday evening through
Wednesday afternoon. The track of the surface low appears to be
too far south and east for North Dakota to experience much in the
way of accumulating snowfall. Only a trace to one inch is expected
at this time. It appears Wednesday will be the warmest day of the
work week for most spots, with highs generally in the mid to upper
teens.
Thursday through Sunday will feature several more chances for hit
or miss light snow showers as a series of upper level shortwaves
propagate through western and central North Dakota. The latest
model guidance keeps QPF amounts low, with very little to no snow
accumulations. In fact, it appears most areas will stay mainly dry
for the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 834 PM CST Sun Feb 17 2019
VFR conditions to begin the 00Z TAF period. Do expect MVFR
ceilings to re-develop at KDIK late this evening, then remainder
of TAF sites 06Z-12Z and continuing through most of Monday
morning before improving to VFR. Latest iterations of mesoscale
models are not as bullish in bringing lower visibilities into the
south central. Will continue to hold off on mention of fog.
Generally light winds through the forecast period.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...TK
LONG TERM...TK
AVIATION...TWH
Area Forecast Discussion
National Weather Service Denver/Boulder CO
820 PM MST Sun Feb 17 2019
.UPDATE...
Issued at 817 PM MST Sun Feb 17 2019
Grids have been updated to account for areas of snow developing
east of the foothills. Some bands brought heavier amounts to
locations from Golden to Evergreen with a narrow area of 3 to 5
inches. This appears to be due to an area of convergence that was
taking place between the foothills and the Denver metro area. An
area of warming cloud tops entered from the east was indicated on
satellite imagery. The surface dewpoints are currently in the
single digits so it`s mostly just cold and dry. There will be a
chance that the dry air will hold the snow at bay, not allowing
much snow east of DIA. Snow accumulations should be highest near
the foothills. Snow will decrease this evening with the incoming
southerly downslope flow.
&&
.SHORT TERM...(This evening through Monday)
Issued at 232 PM MST Sun Feb 17 2019
A short wave ridge over Colorado brought mostly clear skies this
morning. This ridge will slide east of the state tonight.
Satellite depicting convective clouds over the mountains and
foothills. The RAP model shows CAPE up to 200 J/kg for this
afternoon. Expect snow showers to form this afternoon and evening
along the Front Range foothills and mountains where the best
instability will be and where an easterly upslope flow will
prevail. Snowfall could be quite heavy for a short time under
stronger snow showers with up to 2 inches in less than an hour.
The snow showers are expected to end by midnight as the airmass
stabilizes, however widespread light snow should form as a short
wave trough lifts northeast over the Central Rockies. Lift from
the short wave trough and easterly upslope flow is expected to
produce light snow into mid Monday morning. Snow will then end or
taper off to flurries as the trough exits the state. More snow
showers are expected to form Monday afternoon over the mountains
as the airmass destabilizes again.
East winds will continue to push cold air into the state today
and tonight. Expect temperatures to fall into the single digits
tonight and only climb into the teens Monday. Snow ratios will be
high, approximately 20 to 1 ratio. Expect the foothills to see the
most snow because of the convection this afternoon and evening
and due to the easterly upslope flow. Here, thinking 2 to 5 inches
with a few higher amounts due to the convection. For Denver,
around an inch on the northeast side to 3 inches over southwest
Denver. Again locally higher amounts will be possible under the
stronger snow showers.
.LONG TERM...(Monday night through Sunday)
Issued at 232 PM MST Sun Feb 17 2019
A complex upper level trough will extend from the northern Rockies
into the southern Rockies Mon night and is fcst to form into one
main elongated upper level low on Tue from wrn WY into wrn CO.
Meanwhile at the sfc, cold high pres will extend from the nrn
Rockies into the central US.
Overall mid level flow will be south to southwest Mon night into Tue
with a decent amount of QG ascent late Mon night into Tue with
marginal lapse rates. Meanwhile low level flow east of the mtns
will generally be southeasterly. For the mtns orographics will be
rather weak with most locations only seeing light snow. Only
exception might be over srn areas of zn 34 and across the valleys
of Park county where southeast flow can produce decent snow.
Over northeast Colorado forecast is rather complicated due to
southeast low level flow and impacts from a Denver cyclone that will
be in place. Position of the upper level jet would favor areas of
the far ern plains late Mon night into Tue for the best area for
decent snow with much lighter amounts further west along the front
range. However, southeast low level flow could allow for higher
amounts in and near the nrn foothills from Fort Collins north to the
Wyoming border. Other wildcard is the Denver cyclone which, if
strong enough, could turn winds more to the east from Denver
northward which would allow for a better shot of snow over the nrn
suburbs of Denver to Boulder and northward. At this point still a
lot of questions so will just keep likely pops in for Mon night into
Tue with light amounts. As for highs temps will remain well below
normal with readings in the mid teens to lower 20s across the
plains.
By Tue night the main upper level will move across into early Wed
with some additional QG ascent. Once again low level flow across
the plains will be south to southeast as a Denver cyclone remains in
place. As the main upper level trough moves across there will be
some additional light snow across the plains. Further west along
the front range the low level flow will become more north to
northeast as the cyclone shifts eastward. As a result this may
enhance upslope flow Tue evening, and as main trough moves across
this could see some enhancement of snow in the evening along the
front range urban corridor. In the mtns will see some light snow
Tue night as well.
For Wed the upper level trough will be east of the area with drier
flow aloft moving across. Outside of a few snow showers in the mtns
it will be dry with moderating temps as readings rise into the lower
to mid 30s across the nern CO.
On Thu an upper level trough will intensify over the wrn US with
increasing west to southwest flow aloft. Some moisture will affect
the mtns by aftn which may lead to a chc of snow. Across nern CO it
will be dry with temps remaining in the 30s.
For late Thu through Fri night there isn`t much agreement between
the ECMWF and GFS with the handling of the upper level trough. The
ECMWF shows an elongated upper level trough moving slowly eastward
into the Great Basin with a substantial amount of energy moving into
the swrn US. Meanwhile the GFS has an upper level trough moving
across the area on Fri. Although the upper air patterns don`t match
up well they do show a couple of things. First off, both models
do show favorable mid level ascent Thu night into Fri, and
secondly, a cold front is fcst move across nern Co enhancing
upslope flow. Thus despite the upper air patterns not matching up
both models would produce some snow across the area along with
colder temps.
By Sat the upper level trough will move either to the east or
southeast of the area with pcpn chances ending.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 817 PM MST Sun Feb 17 2019
Light snow will be present across the are tonight into early
Monday morning. Heavier snow showers could cause localized LIFR
conditions until 06Z. A quick inch or two will be possible with
any heavier snow showers. At KDEN, expect around an inch of snow
by Monday morning with KAPA could receive two to three inches with
heavier bands. Snow will end around 16Z Monday morning. Clouds
will also lift, due to the southerly downsloping winds through
Monday.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Sullivan
SHORT TERM...Meier
LONG TERM...RPK
AVIATION...Sullivan
Area Forecast Discussion
National Weather Service Duluth MN
850 PM CST Sun Feb 17 2019
.UPDATE...
Issued at 850 PM CST Sun Feb 17 2019
Lake effect snow chances will be the short term concern. Snow
showers earlier this evening have diminished but latest satellite
and radar shows a growing area of returns over far western Lake
Superior and we expect this to continue tonight and affect areas
as far west as Douglas County. The RAP shows a rather deep layer
in the max dendritic snow growth layer but the airmass is rather
dry so it will be fight between the favorable thermal profile and
the dry air. We have increased POPs along the South Shore and
added some accumulation but generally kept amounts light for now.
The low level winds will remain northeast through much of the
night but will gradually back after 08Z or so becoming north by
mid to late Monday morning.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 355 PM CST Sun Feb 17 2019
Generally quiet conditions are expected through the short term as
the main storm track remains to the south of the area. Only
concern is the light lake effect snow along the North and South
Shores of Lakes Superior.
Upper level low pressure is seen near Sioux City, Iowa, this
afternoon with a longwave trough extending back to the northwest
into the northern High Plains. At the surface, an area of low
pressure in the western Ohio Valley trails an inverted trough to
the northwest into the Red River Valley of the North. Areas of
snow are seen along the trough, but this activity is having
difficulties making it north of I-94 in Minnesota. The edge of the
cloud shield has pushed into the southern CWA, but have yet to see
any reports of snow in our CWA despite some light radar returns.
Dry air and lack of saturation are keeping things dry in the
Northland from this system. Further north, onshore winds off Lake
Superior have led to some lake effect snow from the Silver Bay
area down into the Twin Ports. Additional bands have developed and
moved over the Bayfield Peninsula and Iron County. Most of this
should diminish heading into the evening hours per hi-res
guidance, but some light flurries may linger into late evening.
Snow showers may persist in Iron County through the night and into
Monday morning before quickly ending during the early afternoon as
winds turn off-shore.
Beyond that, dry conditions are then expected through Monday
night as weak high pressure moves through. Some northern areas
may clear out tonight, leading to better radiational cooling
conditions. Most areas will be in the single digits below zero,
but areas that clear out will have no issues getting into the
teens below zero. Highs will reach into the teens on Monday before
cooling back into the single digits below zero Monday night.
.LONG TERM...(Tuesday through Sunday)
Issued at 355 PM CST Sun Feb 17 2019
A fairly active weather pattern will remain in place across most of
the continental U.S. from mid week through next weekend, but the
atmosphere has acquired a flow regime that is now (finally) closer
to what one would expect during an El Nino winter - with a very
active southern stream storm track, and a weaker northern stream
from the Canadian Prairie provinces to the northern Great Lakes. For
the most part, this will leave the Northland in between storm
tracks, with comparatively quiet weather compared to locations
farther north, or south. The other major effect this will have on
the Northland is that temps will be near, or slightly below normal,
rather than the bitter cold that has dominated much of the past
month.
The best chance for organized precipitation, in the form of
widespread light to moderate snow, appears to be Tuesday night and
Wednesday with a well-organized mid level trof ejecting from the
central Plains into the Great Lakes region. At the moment, this
doesn`t have the look of a major storm for the Duluth CWA, but given
available model guidance, amounts as great as 4-6 inches could be on
the table across much of northwest Wisconsin, with lesser amounts
the farther north and west one goes. Given the timing, with snow
moving in overnight Tuesday, there could be some impacts for
Wednesday morning travel/commute activity. We will need to monitor
model trends closely the next 24-36 hours, as a subtle northwest
shift in the path of max forcing for ascent could push the heavier
snow amounts northward across a much larger portion of our CWA.
Beyond that, a series of weaker disturbances in both the northern
and southern storm track will deamplify as they approach the
confluent mid level flow over the Lake Superior/Ontario area, which
will result in continued period chances for light snow. Most
operational model runs are now considerably farther south with the
storm system for next weekend, but we will continue to monitor.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 540 PM CST Sun Feb 17 2019
Much of the Northland will be under VFR conditions through the
period. The exception will be around Lake Superior, mainly from
around Silver Bay to Duluth and into northern Wisconsin where MVFR
and possible IFR ceilings will be possible. These ceilings will
occur through tonight, and in the case of northern Wisconsin, well
into Monday. There will be periodic snow showers as well,
especially along the South Shore and the visibility may dip to 1
to 3 miles and at times to a half mile like recently observed at
KASX.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH -3 16 -1 17 / 30 10 0 0
INL -12 11 -11 14 / 0 0 10 0
BRD -3 15 -7 14 / 0 0 0 0
HYR -1 19 0 20 / 30 0 0 0
ASX -1 17 0 21 / 70 50 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...Melde
SHORT TERM...BJH
LONG TERM...Miller
AVIATION...Melde
Area Forecast Discussion
National Weather Service Northern Indiana
708 PM EST Sun Feb 17 2019
.SYNOPSIS...
Issued at 700 PM EST Sun Feb 17 2019
An upper level system will spread snow across the area into early
tonight. Areas of freezing drizzle, especially south of Highway
30 will make roads extremely slick at times tonight. Snow amounts
will be up to 2 inches, along and north of Route 6 with lesser
amounts south. Lows tonight will be in the upper teens to lower
20s with highs Monday from 25 to 30. Another system will bring a
wintry mix late Tuesday night through midday Wednesday.
&&
.SHORT TERM...(This Evening through Monday)
Issued at 339 PM EST Sun Feb 17 2019
The dry slot was translating across the area as meso CSI bands
were trying to get going from near the IL/IN border to northwest
Indiana. HRRR/RUC still favoring intensifying bands this afternoon
whereas the GFS was really inhibited. Favor the HRRR and RUC which
appears to have somewhat of a handle on this activity. Patchy
freezing drizzle will persist into this evening in basically
shallow cloud layers where ice is not present. Have trimmed snow
amounts back just a little given the recent model, radar and
surface obs and trends. It looks like snow amounts will be around
a trace with a light ice coating south and southwest of Fort Wayne
to 2 inches north near the Michigan border locally 3 inches or
higher in the bands.
&&
.LONG TERM...(Monday Night through Sunday)
Issued at 339 PM EST Sun Feb 17 2019
The overall upper air pattern should modify by this weekend as the
bulk of the energy begins to eject east. In the interim, smaller
scale upper trofs will eject out of the large dominant upper trof
and may be able to tap some moisture for snow by the middle of
this week. Thermal profiles have trended toward more of a shallow
cold layer with a better chance for freezing rain as temperatures
linger below freezing Tuesday night into early Wednesday. Much
heavier rain should stay well south of the region where flooding
rains are eventually likely. Temperatures should moderate by late
in the week with highs around 40 to 45 from Friday through Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 700 PM EST Sun Feb 17 2019
A few more hours of FZDZ likely for KFWA with shallow moisture
depth preventing ice nucleation. Slightly deeper moisture across
northwest Indiana and upstream along with eventual wrap in of
colder air bodes better for mainly snow, but on northwest fringe
of FZDZ right now and may provide a few, brief mix of light
FZDZ/SN over the next couple of hours. Confidence, however, is too
low for inclusion at this time. Eventual backing of low level
flow and increased subsidence should lead to ceiling consistently
above fueling/alternate midday Monday.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Murphy
SHORT TERM...Skipper
LONG TERM...Skipper
AVIATION...Murphy
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