Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/02/22
Area Forecast Discussion
National Weather Service Cheyenne WY
751 PM MST Tue Mar 1 2022
.UPDATE...
Forecast looks on track this evening. Continuing to watch wind
gusts in the wind prone areas reaching the 40-50 mph range, but
this is still expected to come down later tonight.
.SHORT TERM...(This evening through Thursday night)
Issued at 300 PM MST Tue Mar 1 2022
The main concern with this forecast package is the unseasonably warm
temperatures and wind speeds during the next couple of days.
Latest water vapor loop was showing the upper level ridge dominating
the western half of the U.S. Our forecast area was still on the
southern edge of the westerlies and deep mixing which has resulted
in gusty winds of 40 to 50 mph in the wind prone areas of Arlington,
Bordeaux and the I-80 summit with even a few gusts to 55 mph during
the last hour. These winds have shown signs of subsiding during the
last couple of hours, but gusty winds may linger through the evening
into the overnight. This will result in mild temperatures again
tonight across much of the area, especially the downslope areas. We
followed closest to the HRRR solutions with these warmer
temperatures.
Wednesday into Wednesday night: Even warmer temperatures are on tap
for the region tomorrow in response to warm temperatures aloft,
downsloping winds and deeper mixing. The only fly in the ointment
that may prevent temperatures from climbing well above guidance is
the potential for mountain wave cloud cover. Not confident about the
duration of this cloud cover, so we did bump up temperatures a few
degrees compared to the previous forecast which agrees with the
blends.
Thursday-Thursday night:
After another unseasonably mild day on Thursday, there is some
question on whether a back door front will be able to creep into the
northern Panhandle early Thursday morning in response to a weak
shortwave aloft. If this boundary can creep into the Chadron area,
they may see some low clouds and patchy morning fog in the Pine
Ridge. However, it should be rather shortlived in response to the
upper level ridge continuing to build into the area.
Temperatures will even be approaching record highs for many
locations.
.LONG TERM...(Friday through Tuesday)
Issued at 300 PM MST Tue Mar 1 2022
Friday will consist of a longwave trough parking itself across the
entire west CONUS, with the remnants of an atmospheric river from
the Pacific Ocean moving onshore in Southern California. Embedded
within this longwave trough will be a shortwave disturbance that
will carve its way toward the Four Corners region of the desert
southwest by Friday afternoon. While this is happening upstream of
our cwa on Friday, we will be enjoying the last day of warm
temperatures. 850mb temperatures across the NE Panhandle per the GFS
are progged at +12C to +19C by 21Z. 700mb temperatures for SE WY
will be in the +1C to +3C by 21Z. The bias corrected grids for the
NAM/GFS/EC/Canadian all have high temperatures eclipsing 70 degrees
for the NE Panhandle, with highs east of the Laramie Range for SE WY
in the middle to upper 60s. Have gone with a slow upward trend for
the highs on Friday because of this guidance trend. Temperatures are
anticipated to rise into the upper 40s and low 50s west of the
Laramie Range in SE WY across the lower terrain, and likely into the
60s for areas east of the Laramie Range by Friday afternoon. Clouds
will increase throughout the day, likely limiting afternoon high
temperatures for several areas, but the southern NE Panhandle is
potentially going to have the latest arrival of cloud cover, thus
have gone with the upper 60s there in addition to the North Platte
River Valley of the NE Panhandle. Lee-side cyclogenesis is progged
to develop by Friday afternoon/evening over northeast CO due to the
pressure tendencies from the upper level shortwave. This is a
favorable area for the northern stratiform precipitation to impact
our cwa. With much above average temperatures being in place across
the region, this will likely present a tough setup for the
precipitation timeline to switch from rain to snow initially. The
GFS is advertising a switchover from rain to snow by daybreak
Saturday morning in the 12Z-15Z window, but the EC continues to hold
onto a colder solution where snow is progged to develop by 6Z-9Z
Saturday for areas along the Laramie Range. Have gone with a blend
between the two, which has lowered the official snowfall forecast
for now. We will have a cold rain before the switchover to snow.
Snow ratios will be low at first...meaning we will likely have a
heavy, wet snow to deal with for areas across the cwa before a
secondary push of colder air arrives via the next shortwave by
Saturday night causing a more fluffy snow transition. The mean GEFS
Plumes for the event show an approximate 6 inch total for CYS. Have
gone against this mean average for now, with a general 2-6 inch
snowfall forecast, with slightly higher totals in the mountain
zones. Model variability has continued to keep confidence in the low
to medium threshold for now. Cold air will be here to stay by
Saturday evening.
The base of the longwave trough will sweep through the area by
Sunday into Monday. This will bring another round of possible light
precipitation. Daytime highs will be in the 20s, to around 30
degrees for Sunday into potentially the remainder of next week. This
would put the area in the 15 to 20 degrees below normal category for
daytime highs if it does indeed occur. Multiple shortwaves are
progged to sweep across the area from the end of the weekend into
next week, reinforcing the cold air across the region. This would
improve the drought conditions across the region, but also keep the
thought of an early springtime at bay. For now, we can look forward
to improved chances of precipitation reducing drought concerns for
the cwa.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 439 PM MST Tue Mar 1 2022
VFR. Wind gusts to 27 knots at Rawlins, Laramie, Cheyenne,
Scottsbluff and Sidney until 03Z, then gusts to 24 knots at all
terminals except Chadron after 15Z Wednesday.
&&
.FIRE WEATHER...
Issued at 300 PM MST Tue Mar 1 2022
Near critical fire weather conditions will be possible during the
next couple days, but fuels are currently not ready. However, very
dry conditions will be in place during the next couple of days with
minimum relative humidites ranging from 15 to 25 percent. Wind
speeds will generally range from 15 to 25 mph with the stronger
winds mainly in the wind prone areas. The pattern will be changing
as we approach the weekend with much cooler temperatures and more
precipitation chances.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...MN
SHORT TERM...REC
LONG TERM...BW
AVIATION...RUBIN
FIRE WEATHER...REC
Area Forecast Discussion
National Weather Service Grand Forks ND
928 PM CST Tue Mar 1 2022
.UPDATE...
Issued at 918 PM CST Tue Mar 1 2022
Current radar shows the highest reflectivity over south central ND
just southwest of the CWA, moving from SE BIS area into ABR area.
There have a been a few reports of rain in Bismarck and Aberdeen,
but overall amounts have been very light. ND DOT highways are
showing green throughout most of the state, and road temps to the
west are ranging from the upper 20s in north central ND to around
36 in south central ND. Overall, there have been no impacts so far
in the FGF area. Echo intensities upstream in north central ND
are increasing, with Minot AFB reporting light snow. I believe we
have a better chance of seeing precipitation across our CWA with
this second round, and CONSHORT and HRRRTL are both increasing
POPs shortly after midnight. A transition from snow to rain and
freezing rain is still expected along a corridor roughly from
Devils Lake to Detroit Lakes. However, with nothing falling to
this point...have removed any mention of ice accumulation from 00Z
to 06Z. Will change messaging to a trace to five hundredths of an
inch, down from the previous forecast but still has the potential
to be quite impactful. Snow further north still looks to be a
trace to about half an inch, locally higher up to an inch
possible but, overall, forcing is fairly weak and no sig snowfalls
expected.
UPDATE Issued at 624 PM CST Tue Mar 1 2022
Low clouds are moving into central ND and our far western zones,
however have not seen any precip reports. It is a matter of
waiting for the column to saturate...and prefer the slightly
slower models such as the HRRR over the more aggressive RAP. The
inherited POP grids reflect this well, and not planning any
changes with the 1900 L update. The 00Z Advisory start time will
more likely be in the 03Z to 04Z timeframe for impacts in the western
zones, and after 06Z for the southern valley. However, some light
DZ could start anytime so will keep hazards as they are, but
greatest impacts won`t get going until after midnight.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 333 PM CST Tue Mar 1 2022
A clipper will bring a widespread dusting of snow to the region
tonight into Wednesday morning, with a wintry mix and light icing
in our west and south.
Main baroclinic zone is just west of our CWA with surface high
pressure continuing to transition over our area. The next clipper is
moving out of Alberta along into southern Saskatchewan, and we
already seeing areas of light returns expanding on regional radars
in northeast Montana. This timing is matching up well with a
consensus of short range guidance which shows it eventually spreading
into our northwest after 6pm and then overspread our CWA through the
late evening/overnight. Models indicate the wave will remain open
with less obvious/weaker synoptic ascent, while any pockets of
frontogenesis are progressive/transient. The signal for light QPF is
there, but amounts should be light and this matches ensemble
trends/NBM probs showing high probabilities of a dusting but very
low probabilities (less than 10%) of 1" or greater. Most precipitation
should be ending by midday Wednesday with a dry period then favored
through Wednesday night to to a stronger influence of mid/upper
ridging to our west/rising heights.
A warm nose is shown to build east this afternoon/evening ahead of
this wave, and HREF FRAM mean shows light icing potential, while
NBM4.1 probs for greater than 0.01" are 30-60% along our western and
southern CWA. It is hard to say how far east potential freezing
rain/drizzle mix would be, but the signal/potential is there and it
only takes a trace of icing to cause dangerous travel conditions.
Considering the signal in guidance, we went ahead and issued a
Winter Weather Advisory for this evening for areas in our far west
and south where up to 0.1" of icing is forecast.
.LONG TERM...(Thursday through Tuesday)
Issued at 333 PM CST Tue Mar 1 2022
Overview...
Periodic chances for light snow will continue through the end of the
week. Then, a robust Colorado low is expected to impact the region
Saturday into Sunday. This will bring with the potential for
accumulating snow, which may be heavy in some areas. Otherwise,
temperatures will remain generally below normal in the teens to 20s.
Thursday and Friday...
Northwesterly flow aloft will begin to shift more zonally as an
upper trough digs in over the western CONUS. As this occurs, the
next shortwave on Thursday is expected to travel to the south and
west of the FA. This will lead to a cooler Thursday with highs in
the teens. The next opportunity for light snow then arrives on
Friday as a midlevel frontogenetical band, associated with an upper
trough moving across the Canadian prairies, sets up over the region.
This feature will likely produce winter weather impacts across the
area, although the degree of these impacts is still to be
determined. Impacts will be tied to the strength of the forcing, as
synoptic forcing looks to be minimal, as well as the residence time
of snowfall in any one area. Overall, light snow is anticipated with
this system, with some potential for heavier pockets if mesoscale
banding sets up.
Saturday through Monday...
There continues to be a persistent signal within ensemble guidance
for a Colorado low to impact the region in some capacity Saturday
into Sunday. Questions pertaining to the exact track of this system,
however, continue to plague ensemble guidance. There seems to be two
general solutions with regards to this system; a southern Minnesota
track of the surface low and a south-central Iowa track of the
surface low. The former solution yielding a higher QPF scenario
while the latter solution yields a lower QPF solution. Despite the
uncertainty in the forecast positioning of this low, the general
consensus is honing in on the solution of at least increasing snow
chances for most of the area Saturday into Sunday. The main
variations will be in regards to the intensity of snowfall across
the southern FA. This is further evidenced by NBM probabilities of
24 hour snowfall exceeding 2" in the 20-40% range across the
northern FA to the 40-60% range in the southern FA. There is
potential for heavy snow in the southern valley into west central
Minnesota as well, as indicated by NBM probabilities of 24 hour
snowfall exceeding 6" in the 10-20% range. All this said, there are
increasing chances for snow across the region, that may be heavy at
times across the southern FA. As the deepening surface low tracks to
our south, gusty winds out the north-northeast are anticipated.
This, in conjunction with falling or freshly fallen snow, may lead
to increased blowing snow potential as well on both Saturday and
Sunday. By Sunday evening, the bulk of this system should have
transitioned eastward out of the forecast area. This will lead into
a quieter period moving into early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 514 PM CST Tue Mar 1 2022
Flying conditions will begin to deteriorate by 06Z tonight, with
significant impacts on the GA community. A clipper system will
move across central and southeastern ND tonight, lowering cigs to
near IFR conds. Worse, however, will be the potential for mixed
precipitation especially at FAR. DVL would also have a decent
chance of seeing FZDZ mixed with SN, however attm it appears to be
north of the transition zone. This will likely occur around or
after midnight, however icing conditions may be earlier...see
aviationweather.gov/icing for the latest official icing
forecasts. Conditions will gradually improve by late tomorrow
morning.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Winter Weather Advisory until 9 AM CST Wednesday for NDZ014-024-
028-038-039-049-052-053.
MN...Winter Weather Advisory until 9 AM CST Wednesday for MNZ003-029.
$$
UPDATE...Speicher
SHORT TERM...DJR
LONG TERM...Rick
AVIATION...Speicher