Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/12/23
Area Forecast Discussion
National Weather Service Duluth MN
530 PM CST Sat Feb 11 2023
.DISCUSSION...(This evening through Friday)
Issued at 303 PM CST Sat Feb 11 2023
Summary: Mild into mid-week with a storm bringing snow and rain
Tuesday into Wednesday (a few inches possible in spots) with a
second storm possible for portions of the Northland Thursday.
Plenty of sunshine cause warm temperatures today with most locations
reaching into the forties, and some near 50 degrees! A shortwave
and weak cold front will move into the region tonight and may
produce some light precipitation. 12Z soundings at KINL/MPX were
quite dry and forecast soundings from the RAP indicate plenty of
dry air will remain in place tonight. Some of the guidance does
spit out a little QPF but we will limit our mention to just some
flurries.
Sunday and Monday will be cooler than today but will still be well above
normal. There may be some fog around Sunday into Sunday night.
Another weak shortwave may again cause some flurries or light snow
in spots Sunday night, mainly along the International Border.
Warmer air arrives again Tuesday ahead of an area of low pressure.
We do expect more clouds and precipitation should develop through
the day, especially over western portions of the Northland. The
clouds/precipitation should hold temperatures back some,
especially when compared to today. Precipitation will expand in
coverage for all areas Tuesday night. Precipitation type will be
a challenge with the low pressure system with warm air in place
initially. The global models are in pretty good agreement
regarding the track and strength of the low. A look at forecast
soundings suggest rain and snow will be than precipitation types,
with rain at first for most then a transition to snow with
dynamic/evaporative cooling. A few inches of snow will be
possible, mainly Tuesday night into Wednesday morning.
Colder air will move in as this first low moves off Wednesday into
Wednesday night. A second low pressure system may impact portions
of the Northland Thursday into Thursday night, with snow the main
precipitation type. Confidence in its track and impacts for the
Northland are lower. The ECMWF has a track that is further
east/south of the deterministic Canadian/GFS which leads to lower
impacts. There is pretty good agreement of the ECWMF`s ensemble
members with the deterministic forecast with a track that is a
bit too far east/south to provide significant snowfall for the
Northland. The GFS ensemble members/mean also favor closer to the
ECMWF. However, there are a couple members from each model that
are closer to the deterministic GFS so it`s too early to say
significant snow is unlikely. If any were to occur, northwest
Wisconsin would be favored. There will be a period of lake effect
snow for portions of the South Shore Thursday into Thursday night
with colder northerly winds occurring.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 530 PM CST Sat Feb 11 2023
VFR conditions to start the forecast period. Satellite does show a
MVFR stratus deck 50 miles north of the International Border but has
been pretty stagnant in it`s movement. Most models also agree with
keeping this cloud deck north of INL. There is a chance for some
flurries this evening as well as some patchy fog developing in the
early morning hours. Confidence is not terribly high in the fog
development due to the dry conditions initially observed this
evening. Some lower clouds may develop by tomorrow morning for INL
and HYR with heights that would degrade flight categories to
MVFR/IFR. However, models are fluctuating on whether the skies will
be more scattered or broken in coverage.
&&
.MARINE...
Issued at 303 PM CST Sat Feb 11 2023
Strong southwest winds continued late this afternoon with some
gusts of 25 to around 30 knots still being observed. These winds
will subside overnight and waves will decrease. We will continue
the Small Craft Advisory into late evening. West or southwest
winds will then occur late tonight into Sunday at or less than 15
knots. Winds will ramp up again Sunday night out of the west
backing to southwest on Monday. Conditions may again become
hazardous for small craft, especially Sunday night into Monday
morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 24 38 22 37 / 10 0 10 0
INL 23 40 20 38 / 10 10 10 0
BRD 20 39 19 38 / 10 0 0 0
HYR 20 39 20 39 / 10 10 10 0
ASX 24 41 23 39 / 10 10 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 10 PM CST this evening for LSZ140>148-
150.
&&
$$
DISCUSSION...Melde
AVIATION...Britt
MARINE...Melde
Area Forecast Discussion
National Weather Service Grand Forks ND
722 PM CST Sat Feb 11 2023
.UPDATE...
Issued at 720 PM CST Sat Feb 11 2023
High clouds cover the forecast area with clearing of these noted
to our west in NW ND. This clearing area will work east tonight.
Once skies clear overnight then there is a risk of fog
development. NBM and HRRR indicate patchy fog formation after
09z with focus in the region from Thief River Falls to Fergus
Falls. That area is included in fog mention currently in the fcst.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 141 PM CST Sat Feb 11 2023
KEY MESSAGES
1.) Unseasonably warm temperatures for our snowpack will continue
for today.
2.) Patchy fog is possible tonight, mainly in the Red River Valley
and east of the valley.
DISCUSSION...
Surface analysis indicates a stagnant pressure field with
persistent westerly winds. This has contributed to continuous warm
air advectinon for most of the area. Temperatures have already
crossed 40 where heat flux is the greatest in northwest Minnesota
(heavily tree-d areas). In the central valley, temperatures remain
in the upper 30s. We are at peak heating so temperatures may go up
a degree or two more, but don`t expect anything above 45, at least
in the valley.
For tonight, winds are expected to decrease with increasing cloud
cover. This should limit diurnal cooling at least a little bit.
Where winds are calmer, the potential is there for some fog to
develop. The greatest chance for this will be in the Red River
Valley and in northwest Minnesota.
For tomorrow, expect more unseasonably warm temperatures in the
mid to upper 30s, crossing the 40s further east.
.LONG TERM...(Monday through Saturday)
Issued at 141 PM CST Sat Feb 11 2023
Overview:
The chance for impacts are possible after Tuesday as we
start to develop a split flow aloft. Potential exists for one or two
systems to interact with our forecast region. Snow and blowing snow
will be possible during this time bringing some type of impacts, but
there is uncertainty on their severity.
Discussion:
Temperatures remain above average underneath this ridge through the
mid week. Impacts remain low for Monday and Tuesday morning. Flow
aloft begins to split Monday into Tuesday. 500mb cluster analysis
indicates a strong upper trough to affect the Central and Northern
Plains. However, there is some uncertainty with the track, strength
of the system, and the potential strength with the ridge that moved
over the Eastern Seaboard that would alter the speed and track of
the system. If the low pressure system remains on a southern track
traveling through Southern Minnesota into Wisconsin then our CWA
could receive more precipitation than a more northern track
occurring from a stronger ridge. There is a wide range of
potentials with the system Tuesday into Wednesday, with a majority
of ensemble members gravitating toward light to potential moderate
snow. 2 inches or greater range around 50-70% across an axis
stretching from Fargo to Baudette, with lower chances further toward
the NW. Anything greater than 4 inches ranges 10-20% across NE ND
and NW MN, while areas toward SE ND and points SW range 20-40%. The
temperatures may also reduce the amount of snow received as the
precipitation could come down as rain. The placement of the
rain/snow line may severely cut into the snow amount and tap into
our moisture feed. In order to get higher snowfall amounts, further
moisture feed and mesoscale forcing are needed. Slight indications
of higher amounts are possible (10%), with frontogentic features but
those remain uncertain as guidance struggles to have a handle on
that.
There are blowing snow potentials Wednesday and Thursday behind the
system. Strong cold air advection will give us a shot of cooler air
and stronger winds from the North. Topographic influence, Cold
advection, and the tightened pressure gradient over the Northern
Plains all favor strong winds for our CWA. Guidance show lapse
rates of around 7-8.0 C/km, mixing down gusts near 35kts at times.
Chances of this occuring are 40-50% across the Red River Valley. The
recent snowfall with the strong winds increase the potential for
blowing snow concerns across the Red River Valley as the cold front
sweeps through. The severity and duration are still in question as
guidance differs, but the probability is there (5-10%) for moderate
blowing snow impacts as especially when strong winds combine with
falling snow.
The models and ensembles continue to track another system that could
possibly impact our region Thursday and Friday with slight snow
showers possible. However the current track is forecasted to remain
south and only the southern Border may see possible snow impacts.
Conditions then turn quiet as we head into the next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 543 PM CST Sat Feb 11 2023
Winds will go near calm tonight in most areas. Cirrus over the
area will clear out so that by later tonight skies will be mostly
clear. With light winds and a mostly clear sky fog is favored to
form in some locations....with NBM and Conshort blends indicating
best potential is from Thief River Falls to Detroit Lakes. For TVF
TAF I didnt go as low as possible, as guidance was showing
potential for 1/2SM vsby. But something to monitor. Also some fog
potential into Fargo as well and kept idea of that potential in
TAF.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Riddle
SHORT TERM...Perroux
LONG TERM...MM
AVIATION...Riddle
Area Forecast Discussion
National Weather Service Goodland KS
404 PM MST Sat Feb 11 2023
.SHORT TERM...(This evening through Monday night)
Issued at 301 PM MST Sat Feb 11 2023
At the start of the short term period, the latest RAP analysis shows
the CWA underneath an upper air ridge that is between an upper air
low over LA and another low off the coast of central CA. Current
satellite imagery shows mostly sunny skies with some high clouds
moving into the CO counties while surface observations show dry
conditions across the CWA. Models forecast that the CWA will stay
underneath the ridge for the rest of Saturday keeping a westerly
flow aloft. At the surface, a surface low looks to reside in eastern
CO during the afternoon and evening that will begin to slide
eastward going into the night. Dry conditions are expected to
persist through the remainder of the day. Overnight lows for tonight
expect to be in the lower to middle 20s.
For Sunday, forecast guidance shows the CWA remaining underneath the
ridge between the two lows which are expected to move over NC and
southern CA respectively by the evening hours. During the afternoon
hours, the upper air flow over the CWA looks to transition to
southwesterly briefly going into the evening with a possible
shortwave disturbance traveling through the flow that will return to
the original westerly going through the night. At the surface, a
cold front looks to pass through the region starting in the morning.
Along with cloud cover expected during the day, daytime highs
will be a bit cooler compared to the previous day. Behind the
front, winds expect to shift to northerly during the day and gust
up to around 15 to 25 kts. Clouds look to decrease across the CWA
going into the night. Daytime highs on Sunday range between the
lower 40s and lower 50s while overnight lows will be between the
lower and middle 20s.
On Monday, models show the upper air CA low moving eastward across
AZ and into northern NM turning the upper air flow over the
southwesterly during the evening hours and then more southerly
overnight. Another feature worth mentioning is an upper air ridge
moving over the Northern Plains. At the surface, chances for
precipitation look to return to the area during the evening and
going into the night. The best chances look to be along and east of
a line from Atwood to Sharon Spring around midnight. Current QPF
amounts look to be a few hundredths at most in eastern portions of
the CWA with precipitation type looking to stay mostly as light rain
though there may be some light snow mixed in if precipitation occurs
along and west of the CO border. In addition to these precipitation
chances, models show a possible 20 mb pressure drop from the morning
going into the night as a lee surface low moves into eastern CO.
Southerly winds gusting up to 30 to 40 kts particularly in the
western portions of the CWA may be possible during the evening
hours. Will monitor these conditions going forward to see if
these winds continue to be seen in model forecast runs. Daytime
highs on Monday look to be in the upper 40s to lower 60s followed
by overnight lows in the middle 20s to middle 30s.
.LONG TERM...(Tuesday through Saturday)
Issued at 139 PM MST Sat Feb 11 2023
Focus for this part of the forecast will be two upper level troughs
moving through the forecast area next week. At this time confidence
low-moderate, but still doubtful regarding the snow forecast for the
latter half of the week.
Beginning Tuesday the weather pattern becomes more active as two
upper level short wave troughs move through the forecast area
separated by a short wave ridge. Currently the first trough is
forecast to product rainfall ahead of it Tuesday. Was skeptical of
rainfall instead of snow occurring in mid February. However the wet-
bulb zero heights support rain rather than snow. A cold front moves
through the forecast area Tuesday as the rainfall ends.
There will be a short break in the precipitation activity as the
short wave ridge moves through. Behind it the next short wave
trough moves in Tuesday night.
The second upper level short wave trough looks to be similar
intensity to the first one. However it will not be diving as far
south before tracking eastward. Models are not in as good of
agreement with this trough as the first one. The GFS has been
slowly shifting the trough north with the new model runs. Comparing
the GFS to the GEFS members shows the GFS is slightly faster with
this trough than the ensembles are; which is no surprise since
models tend to move closed lows too fast. The ECMWF has remained
slightly to the south. However, looking at the last five models runs
of the ECMWF, it too is shifting the trough to the north.
The center of this trough closes off and is close to tracking along
the favorable corridor for producing widespread moderate to heavy
snowfall for the forecast area. One concern is the track of the
trough is not as far south over the Desert Southwest before turning
to the east as would be expected for heavy snow events. (The closed
low center moves over the Four Corners Region when heavy snow
producing systems usually move more south of there before turning
east.)
Looking at CIPS Analogs for perspective, there are two upper level
patterns from prior events that are eerily similar to the one that
is forecast; 2/1/2002 and 1/21/1990. Both these events had the
closed low moving into the forecast area from the southwest,
producing six inches or more of snowfall across a rather wide area.
In addition, the probability for wind gusts above 35 MPH is atleast
50% based on similar past weather events. However there are still
events that looked similar which did not produce heavy snow amounts.
The track of this system into the forecast area is not the most
favorable for heavy snowfall, however it does have the potential to
produce heavy snow amounts based on similar past events. Bottom
line, heavy snow is likely to occur but the question is where on
the Plains will that be.
After the second upper level short wave trough moves through a short
wave ridge will move over the forecast area at the end of next week.
Assuming there will be some type of snow produced, am thinking highs
for Friday and Saturday are on the warm side.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 403 PM MST Sat Feb 11 2023
Both terminals will see VFR conditions through the forecast
period. Winds for KGLD, southwest around 10-15kts through 05z
Sunday, then west. By 09z, becoming northwest 5-10kts then north
by 15z around 10-20kts. Winds for KMCK, south around 10kts
through 02z Sunday, then light/variable. By 10z, becoming north-
northwest 10-20kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...076
LONG TERM...JTL
AVIATION...JN
Area Forecast Discussion
National Weather Service Pocatello ID
136 PM MST Sat Feb 11 2023
.SHORT TERM (Tonight - Sunday)...
Afternoon satellite imagery shows an upper low off the central
California coast which will continue to sag south into SoCal over
the next day. Closer to home, southwesterly flow ahead of the
California low has helped stream mainly mid and high level clouds
across much of eastern Idaho. Still seeing some decent sunshine
however and temperatures have warmed into the 20s and 30s across
many of the valleys although we do have some isolated colder pockets
in the areas have that been running cold for much of the past few
weeks with more snowpack. Upper-level flow becomes more variable
later this evening and clouds should start to clear out as we
approach sunrise on Sunday as the upper flow becomes more northerly.
This will keep temps a touch cooler tomorrow compared to today but
still just a few degrees below seasonal levels. McKaughan
.LONG TERM (Monday through Saturday)...
An upper trough is taking aim at the Intermountain West starting
Monday. Models are consistently showing the trough deepening
through the next few days as it is expected to dive into the Four
Corners region by Wednesday morning. Onset of snowfall looks to be
sometime Monday afternoon or evening in the Central Mountains.
The rest of the forecast area should see snow beginning in the
evening or late night Monday. NBM probabilistic guidance shows the
best chances of 4+ inches of snowfall is the Island Park area and
the Big Hole Mountains (60 to 70 percent chance). The associated
cold front should pass through the area Monday night, adding a
second component to weather impacts: winds. With the passage of
the front, sustained winds jump to 30 to 40 mph between Blackfoot
and Burley in the early morning hours on Tuesday. By Tuesday
afternoon, cold air is seen in the models spilling over the
Divide. This will lead to a sharp increase in windspeeds along
Monida Pass and increased north/northeasterly winds down the Snake
Plain. With the combination of snow and blowing snow, winter
storm impacts could linger along the Divide through Tuesday night.
The trough should exit to the east by Wednesday as we come back
under upper ridging and fair weather until the weekend. Models are
suggesting another trough will approach from the northwest.
Hinsberger
&&
.AVIATION...
Dry conditions are expected to continue as a split upper
low dives southward along the California coast today and tonight.
Precipitation will mostly remain in proximity of the low. High
clouds streaming over Idaho from the south will begin to dissipate
and move southeast tomorrow morning. HRRR and HREF are indicating
the potential for LIFR fog/stratus tomorrow in the Snake Plain,
particularly at PIH and IDA. NBM is showing increased probability of
IFR/LIFR starting around 09Z to 10Z, but prevailing VFR is forecast.
Winds should remain light through the period. Hinsberger
&&
.AIR QUALITY...
An Air Quality Advisory is in effect for Franklin County through
Monday afternoon due to degraded air quality. The AQI is currently
moderate category as low-level inversions persist with little
mixing expected. Conditions are expected to deteriorate, and is
forecast to be in the "Unhealthy for Sensitive Groups" category.
Hinsberger
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$