Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/05/20
Area Forecast Discussion
National Weather Service Bismarck ND
916 PM CST Sat Jan 4 2020
Issued at 916 PM CST Sat Jan 4 2020
Stronger winds have now developed across northwest North Dakota.
At 9 PM CST, the Williston Airport reported sustained winds at 35
mph with a peak wind gust of 51 mph. Should see these winds
continue to expand eastward through the rest of the evening.
Temperatures have been rising this evening behind the initial wind
shift, which is now approaching the James River Valley. Expect
temperatures mainly in the upper 30s to lower 40s until the main
push of colder air arrives from southern Saskatchewan/northeast
Montana in the next couple hours.
Radar and surface observations show an area of precipitation
over Glasgow, MT at 9 PM CST, moving east-southeast. The 00Z HRRR
and RAP have picked up on this, and have been simulating it well
over the past couple hours. Projections bring this precipitation
into southwest North Dakota around 06Z. Expected types are rain or
snow, based on surface temperatures.
The Glasgow ASOS recorded a wind gust of 66 mph as the
aforementioned precipitation moved through. This precipitation
appears to be the extra nudge needed to bring the intense low
level winds we have been anticipating down to the surface. Will
closely be monitoring wind gusts as the precipitation moves across
eastern Montana. If +60 mph gusts continue to be observed, a
short-fused High Wind Warning may need to be considered for parts
of western North Dakota.
UPDATE Issued at 603 PM CST Sat Jan 4 2020
The arrival of strong winds in western North Dakota continues to
be delayed from what guidance had previously been advertising.
The most recent runs of the RAP and HRRR now suggest winds ramping
up over the 02-03Z time frame (8-9 PM CST). Other than the slower
start time of strong winds, the ongoing wind forecast and Wind
Advisory remain on track. Have only seen sporadic +50 mph wind
gusts in central and eastern Montana this afternoon during peak
mixing, so agree with the previous forecast that High Wind Warning
criteria will have a hard time being reached tonight.
Other changes for this update include increasing sky cover this
evening based on satellite and webcams, and adding an isolated
snow shower mention along and north of Highway 2 as the best
forcing from the mid level shortwave moves through. Any snow
should move through quickly and be light given a dry lower
.SHORT TERM...(This evening through Sunday)
Issued at 156 PM CST Sat Jan 4 2020
The main issue in the short term period will be the winds. Currently
we have a High Wind Watch in effect for the entire CWA. The question
will be whether or not the stronger winds aloft (generally 850 mb
winds of 50 to 55 knots on both the GFS and NAM) can reach the
surface. We know the potential is there with the strong winds at 850
mb and even stronger not far above that. However, there are some
indications that the strongest winds will have a hard time reaching
the surface. Most guidance is below our current wind forecast, which
makes me wonder if we are reaching too far to obtain these winds.
The surface low tracks north of the forecast area, with a good
surface gradient setting up overnight. Both the GFS/NAM have about a
20 mb difference between northeast and southwest ND around 09 UTC.
The cold advection is decent but nothing out of the ordinary. The
same can be said for the isallobaric component, with the strongest
fall-rise couplet moving over the far southwest in the evening, then
tracking along the International Border overnight. Also, the
strongest cold advection is basically right along or possibly just
ahead of the strongest isallobaric component. Again, good but not
great. There are some strong 1000-850 mb lapse rates. They generally
trail the strongest cold advection over the south, and line up a
little better with the strongest cold advection across the north.
This would suggest highest gust potential would be across the
north, which is consistent with our previous few forecasts.
I`ve always been a fan of MOS guidance when it comes to winds and
both the GFS and NAM mos guidance are showing a period of
stronger winds, with the highest (sustained 29 knots) at Minot 06Z
(MAV) and 06-09Z (MET). The other MOS points are similar, but not
as high. This would put us within Wind Advisory criteria for
sustained winds. Would like to see sustained winds a little higher
for HWW criteria. However, we still have the gust potential.
BUFKIT forecast winds for NAM/GFS are pretty similar. Determining
how much mixing we see is the main problem. If you push your
momentum transfer potential a bit higher (10mb above the
inversion, instead of 1mb) you start to see the 55-60 knot winds
making it to the surface. If you keep it lower, they don`t mix
down. So what`s one to do? We`ve been messaging the strong winds
for some time now so whether it`s a HWW or a high end Advisory, I
don`t think there`s much difference really. I think there probably
will be some (normally windy) areas that see a gust around 60
mph, but will these gusty winds be widespread enough to warrant a
HWW. Given the unfavorable timing (diurnal min), the lack of
strong cold advection or strong isallobaric component, think we`ll
go with a high end advisory. We also delayed the timing a bit
from the previous forecast. It seems a bit odd, but we are
beginning the advisory around 01Z in the west, and this is
probably a bit early, and 06Z in the east. We kept the advisory as
2 segments with Burleigh county grouped with the midnight start
time, and Morton county grouped with the earlier start time.
The precipitation is minimal with this system. Did keep some very
light pops along the International border, closest to the surface
and mid level trough. The blowing snow model only produced some
patchy blowing snow over the Turtle Mountains and southern James
The latest NAM just coming in, looks even slower with the passage
of the upper level trough. This could slow things down enough
that the gusty winds may linger into the afternoon Sunday over far
eastern portions of the forecast area. Will leave that for later
shifts to figure out. The strongest winds aloft will have passed
but we could potentially mix out more.
.LONG TERM...(Sunday night through Saturday)
Issued at 156 PM CST Sat Jan 4 2020
A clipper system drops southeast from Alberta into southeast
Saskatchewan Sunday night, with generally quiet weather and
seasonably mild overnight temperatures.
The clipper then moves into southern Ontario on Monday, then
across the Northern Great Lakes Monday night. This will bring
another bout of strong winds to the forecast area Monday afternoon
and Monday night. There may be a little light snow associated with
the mid level shortwave, but it appears to be minimal, and just a
glancing blow with higher precipitation potential north and east
of us. There will be some significantly colder air behind this
clipper, which will linger through Tuesday as the cold surface
high lingers over the forecast area Tuesday. There will be a
significant difference between highs Tuesday over the Turtle
Mountains, compared to the far southwest (single digits above
zero, compared to lower 30s). This gradient in temperatures will
continue into Wednesday as the baroclinic zone lingers over the
area. A northern stream wave, will push the baroclinic zone east
Wednesday afternoon through Thursday, and will also provide a
chance of snow, mainly along the northern half of the forecast
area during this timeframe. Snow amounts will be light, but could
add up to a few inches before all is said and done Thursday
evening. Meanwhile, during this same timeframe (Tuesday afternoon
through Thursday), leeside cyclogenesis in the central and
southern Rockies results in a Colorado low developing over the
central plains and moving into the Great Lakes region. At this
time these two streams of energy remain separate until they try to
merge around the Great Lakes region, which at this time keeps the
precipitation associated with the southern system mainly confined
to the far southeast CWA as the surface system deepens over the
Great Lakes late Thursday into Friday.
Beyond Friday it looks like cold temperatures continue with mainly
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 603 PM CST Sat Jan 4 2020
VFR conditions are expected through the forecast period. The big
story will be strong winds beginning this evening across western
ND, spreading into central ND overnight into Sunday morning. With
the passage of a cold front, winds will shift more westerly and
eventually northwesterly. The highest winds overnight will be
across the northern third of the state, where gusts to 50 kts
will be possible. Elsewhere, expect gusts to 45 kts. A Wind
Advisory is in effect from 01-12Z for the western half of ND, and
06-18Z for the eastern half. Low level wind shear will also be a
concern through Sunday morning. Generally expecting 1500 ft winds
reaching 50-60 kts out of the west-northwest.
Wind Advisory until 6 AM CST /5 AM MST/ Sunday for NDZ001>004-
Wind Advisory from midnight tonight to noon CST Sunday for
Area Forecast Discussion
National Weather Service Glasgow MT
826 PM MST Sat Jan 4 2020
Winds are gusting at or above high wind warning criteria as we
speak, so decided to extend the warning another couple of hours
(until 11 pm) for the counties that were set to expire at 8 pm. In
fact, KGGW gusted to 66 mph at 741 pm.
Next up is the precip. Added some low-end POPs for the southeast
earlier since there was rain and/or snow showing up on the radar
and at the ground, including here at the office. Then there was
another area of precipitation -- picked up well by the HRRR --
that began to move into northwestern Phillips County and is
currently moving through the heart of the CWA now. BREF products
from the radar have been showing some impressive values, as high
as 91 mph (!!!) about 1000 ft AGL and 110 (!!!!) mph about 2000
The surface winds in the central and eastern part of the CWA had
been behaving themselves relatively speaking, while in the west
(particularly southern Phillips County, and possibly Petroleum
County), where snow cover is lacking, had been hitting high wind
warning criteria much of the day. The KGGW 0z sounding had quite
an inversion up to about 600 ft. AGL, with 30 kt. winds there
while the surface was still a relatively peaceful 10 kts. or so.
Once this area of precipitation got going, it was able to transfer
those winds just off the surface at around 1000 ft. AGL down to
the surface almost like a summertime MCS.
Current headlines for High Winds will be left alone with this
package as window of highest winds look to be from 3 pm-9 pm.
850mb winds reaching speeds that are uncommon (approaching 70 kts
in the central zones around 03z) that are hard to ignore. Models
have underplayed strong winds in this area and with the lack of a
deep snowcover, winds tend to be stronger as higher temps lead to
better mixing/lapse rates. Winds will gradually calm down later
On Sunday, winds will be diminishing but still breezy as strong
winds at mid-levels remain and flow at the surface direction is
similar. Temperatures will be cooler with highs near 30 north to
the low 40s south - still above normal.
A weak front moves in early Monday that may bring high winds to SW
Phillips county otherwise the next system moves in Monday Night.
Some snow/rain look to threaten the SW zones and central Montana.
An inch or less of accumulation can be expected. Went a bit higher
on pops/qpf with this system that agrees with neighbors as well.
Uncertainty arises beyond this as the pattern becomes more
unsettled. The GFS is showing some snow and an arctic airmass
holding the area in it`s grips, while the ECMWF is lifting it
northeast later this week. Model blend at this far out looks good.
FLIGHT CONDITION: VFR, with periods of IFR possible this evening
as snow moves through the TAF sites.
WINDS: Becoming W 30-45 kts with gusts to 60 kts this evening,
decreasing to 15-25 kts with gusts to 30 kts overnight, then W-SW
10-15 kts on Sunday.
DISCUSSION: Area of snow is transferring strong winds down to the
surface across parts of Northeast Montana now, impacting KGGW &
KOLF. This area of snow will approach KGDV & KSDY late in the
evening and into the early overnight hours. Sunday will be much
more tranquil, with lighter winds and clearer skies.
High Wind Warning until 11 PM MST this evening for Central and
Southeast Phillips...Central and Southern Valley...Garfield...
McCone...Northern Phillips...Northern Valley...Petroleum...
High Wind Warning until 3 AM MST Sunday for Daniels...Dawson...
Eastern Roosevelt...Richland...Sheridan...Western Roosevelt...
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
954 PM EST Sat Jan 4 2020
A cold front will cross the area tonight, followed by high
pressure building in from the west Sunday through early next
week. A cold front with limited moisture is forecast to move
through the area Tuesday. High pressure builds back into the
area Wednesday and Thursday, then moves offshore Friday with a
frontal system approaching next weekend.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 950 PM Sat...Winds have been a bit slow to pick up but
finally starting to see some gusts over the western part of the
area, just behind a cold front. Wind gusts over 20 kts this past
hour at both Greenville and Kenansville. The latest HRRR has
this surge of wind modeled well, reaching the inland rivers and
highway 17 corridor by 04Z and the Outer Banks by 06Z. The other
item of interest we have been watching is an area of showers
over the greenville area now, moving east. Will increase rain
chances up north to likely to account for this rain, but lower
them farther south to slight chance with model trends confirming
Breezy winds will develop across the area for the early morning
hours Sunday, with strong/gusty winds along the coast,
especially for the southern OBX, where a wind advisory remains
in effect. Skies will clear quickly behind the front, and temps
will fall at a rate of about 1-2 degrees/hour, resulting in lows
in the upper 30s inland, and lower-to-mid 40s along the coast.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
As of 330 PM Sat...High pressure builds in from the south and
west as heights rise aloft, resulting in deep layer subsidence.
Breezy NW winds in the morning gradually diminish through the
day. Despite sunny skies, the morning CAA will limit high temps
to near normal.
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
As of 3 PM Saturday...Cooler and drier conditions are expected
early next week as high pressure dominates. A cold front with
limited moisture is forecast to move through the area Tuesday
with cool high pressure building back into the area Wednesday
and Thursday. The high will move offshore Friday with another
frontal system approaching next weekend.
Sunday through Tuesday...High pres will build across the area
Sun and Mon with dry weather expected. A mid-level shortwave and
attendant cold front push across the area late Tuesday/Tuesday
evening. Moisture will be limited with PW values only increasing
to around 3/4" and fairly shallow saturated layer between
850-700mb, which remains below the dendritic growth zone, so not
expecting much QPF with this system. Models are a bit faster
with the system and expect most of the precip to push offshore
by midnight Tuesday night. Highs in the low to mid 50s Sunday
gradually moderates to around 55-60 Monday and low to mid 60s
Wednesday and Thursday...High pres builds back in from the W
Wed into Thu. Temps return to closer to normal this period with
highs mainly in the 50s and lows in the 30s inland to lower 40s
coast Tue night and below freezing inland Wed night.
Friday and Saturday...The high slides offshore Thursday night
and Friday with a warm front lifting north across the area.
Southerly return flow will bring warmer temps and could see a
few showers moving onshore as low level moisture increases. A
stronger frontal system will approach the area but 12z models
are not in good agreement with the details and timing. The GFS
offers the more progressive solution and pushes the mid-level
shortwave and front through the area fairly quickly late
Saturday/Saturday night, however the CMC/EC maintains a stronger
ridge offshore and lifts the shortwave into the Great Lakes
with the front remaining to the west keeping the area in a
southerly flow/showery regime through the weekend with temps
well above normal.
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Short Term /through 0Z Monday/...
As of 700 PM Sat...VFR expected through the end of the TAF
period with the main aviation concern being gusty winds. After a
brief lull in the winds earlier this evening, a cold front will
usher in much stronger winds within the next few hours. In
general gusts to 20 kts are likely overnight into early Sunday
afternoon. Based on observations to the west, a brief period of
gusts to 30 kts is possible right behind the front, which will
be between now and 03Z. Mid clouds around 6,000 and a light
shower or two will have little to no impacts on the terminals.
Best shower chances would be at KPGV through 03Z.
SKC builds in later tonight and through Sunday. Northwest winds
eventually die down toward sunset Sunday evening, under 10 kts.
Long Term /Sunday night through Thursday/...
As of 330 PM Sat...VFR conditions are expected into Tue as dry
high pres builds over the area. A cold front with limited
moisture will produce scattered showers late Tue and Tue
evening and could see a brief period of sub-VFR conditions.
High pressure will build over the area Wed with pred VFR
Short Term /Through Tonight/...
As of 1000 PM Sat...West south-west winds mainly 15 to 25 kts,
except higher gusts over the Gulf Stream with Diamond gusting to
37 kts. The surge of stronger winds should arrive over the
inland rivers and sounds between 04Z and 06Z, and after 06Z over
the coastal waters. The previous forecast looks to be in good
shape with a cold front just about to move through the waters. WNW
gales develop quickly behind the front, and Gale Warnings have
been extended to cover all of the waters from late tonight into
Sunday morning. Additionally, these strong winds will push the
water to the eastern side of the Pamlico Sound, resulting in low
water conditions for the tidal waterways on the western side of
the Pamlico Sound, and a Low Water Advisory has been issued
accordingly. Seas will build significantly offshore, with the
WNW winds bringing seas to a peak of 7-11 ft around sunrise
Conditions gradually improve through the day Sunday as high
pressure builds in from the south and west. Expect Gale Warnings
to be replaced with SCAs as breezy NW winds diminish through
the day, with seas likewise diminishing.
Long Term /Sunday night through Thursday/...
As of 345 PM Sat...High pressure builds in from the west into
early Tuesday with W winds around 15-20 kt and seas around 3-6
ft Sunday night, diminishing to 10 kt or less with seas
subsiding to 1-3 ft Monday afternoon. Winds are then forecast to
become SW and increase rapidly Tue afternoon and evening to
20-25 kt ahead of the cold front. Winds will then become W 20-25
kt behind the cold front Tue night and Wed. Seas build rapidly
to 3-5 ft Tue afternoon and 5-9 ft Tue night then subside to 4-6
ft Wed afternoon in the offshore flow. Winds veer to N and NE
Thursday and diminish around 15 kt or less with seas subsiding
to 2-4 ft.
As of 330 PM Sat...Strong post-frontal W winds of 25 to 35 kt
with higher gusts will occur tonight into early Sunday, which
will bring a threat of minor sound-side coastal flooding to
Hatteras and Ocracoke Islands. Current guidance is showing water
levels peaking around two feet above normal resulting in
inundation of 1-2 ft above ground level Sat night and Sunday
morning in areas adjacent to the Pamlico Sound south of Oregon
Inlet. Only minor impacts are expected at this time.
Further north, minor water level increases along the soundside
Outer Banks from north Nags Head to Kitty Hawk are possible, but
no impacts are expected in that area.
NC...Wind Advisory until 8 AM EST Sunday for NCZ204-205.
Coastal Flood Advisory until noon EST Sunday for NCZ204-205.
MARINE...Low Water Advisory until noon EST Sunday for AMZ136-137.
Gale Warning until 7 AM EST Sunday for AMZ131-136-137-230-231.
Gale Warning until noon EST Sunday for AMZ135-150.
Gale Warning until noon EST Sunday for AMZ152-154-156-158.