Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/20/21
Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
543 PM CST Tue Jan 19 2021
For the 00Z TAFs, a surface trof of low pressure will deepen over
eastern CO and eastern NM on Wednesday. The associated pressure
gradient will result in gusty southwest winds at the terminal
sites from around 16Z Wednesday through the afternoon hours.
Periods of mid and high level clouds are also expected during this
.PREV DISCUSSION... /Issued 254 PM CST Tue Jan 19 2021/
SHORT TERM...Tonight through Tomorrow Night...
Dry air is filtering in through the day today with the light snow
and flurries coming to an end across the northwest. Clouds are
beginning to clear across the Panhandles with scattered clouds
possible through the rest of the day. Temperatures are struggling
to warm into the lower 40s across most of the Panhandles with the
cloud cover that persisted most of the morning. With skies
clearing, the temperatures may be able to rise into the lower to
mid 40s across most of the area.
RAP 500mb analysis shows a closed upper level low pressure system
meandering towards the Pacific off the coast of southern Cali
where it will remain stationary through tomorrow night. Meanwhile,
a shortwave trough will move across central Canada with an 850mb
closed low swiping just north of the Great Lakes. West
southwesterly winds aloft with surface winds out of the southwest
ahead of the surface trough extending from the closed low. With
southwest surface winds, temperatures will recover nicely and warm
into the upper 50s to lower 60s. A 35 to 45 knot 850mb jet will
just clip the northeast Panhandles with some daytime mixing, winds
will may gust as high as 40 knots at the surface.
Elevated fire weather conditions are possible tomorrow in the
northeast Panhandles. Southwest sustained winds of 15 to 25 mph
are possible with gusts up to 30 to 35 mph. Minimum relative
humidity values will be above 25 percent across the Texas and
Oklahoma Panhandles. ERC percentiles are the highest in the
northeast in the 50th-69th percentile, along with a few spotty
areas int he 70th-89th percentile. The fire weather conditions
are driven mainly by the wind speeds.
LONG TERM...Thursday Through Monday Night...
Cutoff low over the Baja area will become more of an open wave trof
and push southwest flow over the Panhandles with warmer temperatures
in the upper 50s to lower 60s across the Panhandles. Some models
hint at a little moisture out of the southeast, so have a slight
chance of rain showers in the southeast Thursday night. Cold front
right now looks to stall out around the northern Panhandles and then
push through in the evening on Thursday, with east northeast winds
and low clouds likely advecting over the Panhandles. Not much will
change on Friday as the cooler air will remain over the Panhandles
under a more zonal flow aloft and thus the highs will only be in the
Another system over the Pacific northwest will be barreling down the
west cost on Friday into Saturday, and will return moisture to the
southern Rockies as an open wave trof Friday night through Sunday.
Most of this moisture will be taken up over the Rockies and it looks
like very little if any will be over the Panhandles. On the plus
side, dry/mild southwest flow will likely bring temperatures back in
the 60s over the weekend, but breezy southwest winds 15-25 mph will
assist in providing these temperatures. Monday is still a little
uncertain, as we might see just enough moisture clip the southeast
to get some rain maybe even a thunderstorm, as well as possible
light snow. A fast moving cold front may overtake the area before
the rain can clear out and provide a brief period of snow.
Confidence is very low in what will happen on Sunday as there`s
quite the model difference.
Area Forecast Discussion
National Weather Service Denver/Boulder CO
804 PM MST Tue Jan 19 2021
Issued at 802 PM MST Tue Jan 19 2021
Looking at the latest data, appears best threat for strong winds
will be Wed morning thru Wed aftn. Cross-sections show best mtn
wave, in the 15z-21Z window, so strongest wind gusts may end up
in that time period. Thus timing of high wind warning could be
somewhat early but will leave it as is to avoid confusion.
Otherwise only minor adjustments to current forecast overnight.
.SHORT TERM...(This evening through Wednesday)
Issued at 218 PM MST Tue Jan 19 2021
The ECMWF and GFS agree that the upper low to our west will
cutoff and move off the coast of California and Mexico tonight.
Continued warming aloft due to warm southwesterly advection around
the low will continue to increase mid level stability tonight.
The temperature profile is beginning to seem more favorable for
mountain wave amplification, and models are trending up on
forecast winds and gusts speeds in the Front Range mountains and
foothills tonight and tomorrow. The HRRR is now showing peak gusts
in the Front Range mountains up to around 75 mph in some areas.
QG fields also show moderate mid level synoptic scale subsidence
up to about 10 mb/hr in the 600 to 500 mb layer above the
ridge line. Cross sections over and across the Front Range show a
decent stable layer with up to 60 kts of flow perpendicular to
the mountains on Wednesday morning and model soundings show a
strong inversion developing between around 750 and 700 mb in the
foothills. These conditions seem sufficient for marginal warning
criteria and are trending up, so we have issued a High Wind
Warning for the Front Range foothills from just after midnight
tonight through late Wednesday afternoon, for possible winds of 35
to 45 mph gusts up to 75 mph. The strongest winds are expected
between 5 AM and noon tomorrow.
Lows on the eastern plains will be in the high teens and low 20s F
tonight, while lows in much of the foothills and nearby plains
will be a few degrees warmer due to downslope warming of mountain
wave winds. Both models predict that the cutoff low will remain
off the coast to our southwest through the day Wednesday and into
the night. Wednesday will be much warmer than today, with highs
expected in the mid to upper 50s F on the plains and mid 30s in
the mountains. It still looks to be dry through Wednesday. Some
flurries in the northern mountains are possible Wednesday, but no
significant accumulation is expected.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 218 PM MST Tue Jan 19 2021
Winds will be decreasing through the evening and overnight hours
as the mountain wave dissipates. Still should be pretty breezy for
the Foothills overnight, with some gusts up to 50 mph possible,
especially during the first half of the night. Windy conditions
will also keep temperatures mild overnight, only dropping to the
upper 20s/low 30s near the foothills. West of the Divide, shallow
moisture and westerly winds could allow for continued cloud cover
and perhaps a flurry or two.
Zonal flow establishes on Thursday with the a jet streak to our
north and south. Cross-sections show a little more moisture aloft
and very weak synoptic scale lift during the day, which should be
enough for some scattered cloud cover through the day. Over the
mountains, the low-level moisture depth increases a bit through
the day, so it wouldn`t be surprising to see some more scattered
snow showers, with very light accumulations. On the plains, not
much to write home about. With increased cloud cover and mid-level
temperatures a couple degrees cooler than Wednesday, highs should
be about 5F lower than Wednesday`s.
Weather pattern turns more active Friday into this weekend.
Influx of Pacific moisture should spread across the state during
the day Friday ahead of an upper level trough. Winds aloft turn
more southwesterly, under a broad overrunning/warm air advection
regime. QG ascent is pretty weak through the day, but there should
be increasing coverage of snow showers on the western side of the
Divide. The trough is expected to cutoff over Nevada Friday night
into Saturday, with continued southwesterly flow and moisture
advection. Synoptic scale lift increases a bit through Saturday,
and widespread light snow is expected for the mountains, favoring
southwest facing slopes. The trough weakens a bit by Sunday and
transitions back to an open wave as it drifts east/southeast.
Cross-sections still show plenty of moisture up to about 400mb,
and orographic snows will likely continue through the day, even as
synoptic scale lift ends up south of the area. System should be
basically clear of the area by the end of the weekend. The start
of the next week looks fairly active as well with another one or
two troughs potentially impacting the area.
For the mountains... a long-duration snowfall is looking more
likely, especially for mountains west of our forecast area. Too
early to speculate on any storm totals here, but at the very least
there`s moisture to track in the medium range. Over the plains,
it`s unlikely any of the moisture reaches the ground as there`s no
real forcing mechanism to help us out. "Best" chance for any
measurable precip over the plains comes sometime Saturday night
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 802 PM MST Tue Jan 19 2021
VFR overnight. Winds have become light and variable at DIA but
should trend to more SSW by 06z.
High Wind Warning from 2 AM to 5 PM MST Wednesday for COZ035-036.
Area Forecast Discussion
National Weather Service Goodland KS
845 PM MST Tue Jan 19 2021
.SHORT TERM...(This evening through Wednesday night)
Issued at 119 PM MST Tue Jan 19 2021
Satellite imagery and 500mb RAP analysis showed northwesterly flow
over the region early this afternoon. The main features observed in
the pattern included a large closed low off of the southern
California coast with weak ridging out ahead across the Four Corners
region. As this low continued to push southward, split flow
prevailed across the central Rockies. At 1:00 PM MST, north to
northwest winds were between 15 and 20 mph, with gusts around 30
mph for portions of the area. Mid to high level clouds had exited
the region ahead of the west coast system as temperatures ranged
in the mid 30s to mid 40s.
Tonight, temperatures fall into the upper teens to low 20s as a
surface trough approaches the region and light winds turn to the
southwest. Dry weather continues with the flow aloft becoming a bit
more zonal and the ridging ahead of the upper low broadening across
the southern CONUS.
Wednesday looks to be a pretty pleasant day overall. Warmer air
filters into the area, with highs forecast in the upper 50s to low
60s. A surface trough extending southward from a low in central
Canada pushes across the High Plains, with winds shifting from
southwest to northwest through the day. With little moisture in
place, dry conditions and sunny skies prevail. Relative humidity
values fall as low as the upper teens to low 20s across a good
portion of the region in the afternoon. Winds look to stay
relatively light, around 15 mph, mitigating fire weather concerns
at this time.
Wednesday night, the low off of the California coast begins its
journey onshore, weakening in the process. A weak cold front
associated with the Canadian system traverses the area in the
evening. No precipitation is expected as temperatures fall into the
upper teens to mid 20s.
.LONG TERM...(Thursday through Monday)
Issued at 247 PM MST Tue Jan 19 2021
At the beginning of the long term period, forecast guidance shows a
westerly zonal flow over the CWA as the northern and southern
jetstreams merge together over the area with a weak trough residing
over southern CA. This trough is absorbed into the joined jetstream
and the westerly flow aloft continues through Friday with another
trough developing over the Pacific coast behind a weak ridge during
Friday evening. On Saturday, the flow aloft begins to turn
southwesterly as the trough out west tilts positively causing the
CWA to be between the trough in the west and the ridge in the east.
This upper air pattern continues going into Sunday at which the
trough starts to move eastward. The GFS continues to show a quicker
eastward progression for the trough compared to the ECMWF as in
previous model runs. On Monday, a jet streak digs in along the
Pacific coast behind a shortwave in the jetstream and places the CWA
underneath the front end of the trough as it redevelops in the west.
Models show uncertainty this far out with the timing on the
redevelopment of the trough, so this situation will be monitored as
it looks to set up a potential system to start out next week.
At the surface, some precipitation may be expected for a portion of
the Tri-State area over the weekend. Friday may see some breezy
conditions as a surface high sets up near MN/IA/SD with another low
over CO. The CO surface low may travel near the Tri-State area
Saturday night into Sunday. As moisture is wrapped around this
system, areas east of a line from Benkelman, NE to Hoxie, KS as well
as the northern part of Yuma county may see a slight chance of light
snow on Sunday morning. Models show a cold air mass possibly passing
into the Tri-State area around the same time. Minimal amounts of
precipitation is expected if it occurs during this time.
The Tri-State area expects high temperatures on Thursday in the
upper 40s to middle 50s followed by Friday seeing highs in the lower
to middle 40s. Saturday`s highs range from the middle 40s in the
northern portions of the Tri-State area to the middle 50s in the
southern portions. Tri-State area highs on Sunday expect to be in
the upper 30s to middle 40s range with highs in the lower to middle
50s on Monday. Tri-State area overnight lows for Thursday expect to
range between the upper teens to the lower 20s followed by Friday`s
overnight lows ranging between the lower to upper 20s. The Tri-State
area expects to see overnight lows in the upper teens in the western
portions to the upper 20s in the eastern portions. Overnight lows in
the upper teens to lower 20s can be expected for the remainder of
the forecast period.
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 845 PM MST Tue Jan 19 2021
VFR conditions are expected at KGLD and KMCK through the period.
Southwest winds up to 10kts at taf issuance will increase toward
15kts or so at KGLD by 09z and continue sunrise. For the daytime
hours winds steadily veer to the west around 17z at speeds near
10kts. From 18z-21z northwest winds of 12 to 15kts with higher
gusts are expected. After 22z winds subside and become light and
variable through 06z.
Area Forecast Discussion
National Weather Service Blacksburg VA
1025 PM EST Tue Jan 19 2021
A disturbance tonight brings yet another round of upslope
showers for the Western Slopes. Following the disturbance,
strong westerly winds bring gusty conditions to the area
Wednesday morning. Another weak disturbance brings precipitation
chances generally for areas in far southern southwest Virginia
and western North Carolina. Following this disturbance, drier
conditions persist into the weekend.
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1020 PM EST Tuesday...
No changes to Wind Advisory or Winter Weather Advisory.
Have slowed down the arrival of upslope snow showers in the
west. HREF and HRRR guidance have the precipitation reaching
southeast West Virginia around 8-9Z/3-4AM.
Tonight, another disturbance is expected to move through the
area, sparking more upslope showers and bringing additional snowfall
accumulation primarily for Western Greenbrier Co. Amounts
should generally top off around 3 inches. Following behind this
disturbance, the LLJ is expected to crank up with speeds
40-60kts aloft. Greatest mixing for the winds will be along the
southern Blue Ridge down into the NC Mountains. It is signaled
that there could be a few isolated gusts within advisory
criteria north of Roanoke along the Blue Ridge, but they will be
too isolated to warrant issuing for at the moment.
Upslope showers start to wrap up tomorrow and transitions to a
rain snow mix besides for the highest elevations as good CAA
continues, along with gusty conditions. Generally, winds should
start to subside after noon tomorrow. The CAA should keep highs
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 200 PM EST
Weak system skirts by to our south Thursday before a fair weather
Decreasing winds as we enter a fairly zonal flow pattern through the
period. The latter half of the workweek will start with a quick weak
mid level wave skirting by just to our south Thursday morning into
Thursday afternoon. This wave may bring just enough lift and
moisture to the North Carolina mountains/foothills and Grayson
Highlands to touch off a little rain/snow. Any accumulations from
snow and ice look to be minor with the highest amounts along the
ridgetops. Elsewhere we are just looking at an increase in cloud
coverage with dry air from a blocking high over eastern Canada
choking the northern edge of the passing wave to our south.
The weak wave of energy quickly passes south and east by Thursday
evening into Thursday night as high pressure starts to push in from
the northern Plains. Before the high gets here another weak wave of
low pressure will pass to our south across the Gulf Coast states
leaving us dry while ushering in additional clouds through the day
As for temperatures, we look to see a bit in the way of moderation.
Highs will return to the upper 30s and low to mid 40s in the west
with upper 40s to low 50s in the east. Overnight lows will remain
chilly in the 20s and 30s with our coldest air arriving Friday night
as the high pulls in.
Confidence remains moderate to high in the short term period.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 200 PM EST Tuesday...
A dry and cold weekend gives way to a potential wintry mixed bag
early next week.
Overall not much change in the in the upper level flow which will
continue to allow cold air to flood in while keeping the storm track
suppressed just to our south. We will continue to watch this pattern
through the weekend though as several pieces of energy work across
the country heading into early next week. The big question that is
yet to be solved by the models is in regards to the placement of the
southern jetstream and an area of low pressure that will eject of
southwestern United States Monday into Tuesday. The GFS and EURO
continue to show varying solutions in timing and placement of these
features. The GFS remains warmer and wetter while the Euro remains
colder with a mixed bag.
For now trended with a blend of the two along with central guidance
which would keep chance Pops in play for both Monday into Tuesday.
Opted for a bit of a bias toward a colder solution in the sense that
we would see some overrunning as a residual cold air wedge will be
left in place thanks Canadian high pressure/weak ridging drifting
east from the weekend.
This is illustrated very well from both the synoptic/ensemble point
of view at least for the start of the event Monday with temps in the
20s and 30s as the southern stream system tracks north from the Mid-
South. As a result a brief period of snow, sleet, and freezing rain
looks likely Monday morning before a change to rain in the afternoon
and evening as warmer air floods in. The question though that remains
as mentioned above is how far that warm air makes it to overcomes
the wedge in the late afternoon and evening. The other issue is the
placement of low with the GFS trending further west leaving us in
the warm sector compared to the EUro which sends the low overtop of
a wedge that is yet to erode Monday into Tuesday. As it stands now,
look for early next week as our next wintry weather event.
Temperatures will be at or slightly below average over the weekend
with highs in the 30s and 40s and overnight lows in the teens and
Confidence remains moderate in the long term period.
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
As of 640 PM EST Tuesday...
VFR and light/variable winds at all TAF sites this evening.
Another disturbance arrives late tonight, dropping ceilings
back down and re-introducing upslope snow showers and mountain flurries
into Wednesday morning. Stations east of the Blue Ridge will
continue with VFR ceilings.
Gusty conditions expected Wednesday with the strongest winds
along the Blue Ridge.
Extended Aviation Discussion...
Thursday-Saturday favor mainly VFR. A storm system is expected
to move from the southern Plains across the Deep South during
this time. Models have trended drier for the Mid-Atlantic
keeping the storm system south of the local region.
VA...Wind Advisory until 1 PM EST Wednesday for VAZ015>017-022-033.
NC...Wind Advisory until 1 PM EST Wednesday for NCZ001-002-018.
WV...Winter Weather Advisory until 1 PM EST Wednesday for WVZ508.
Area Forecast Discussion
National Weather Service San Angelo TX
551 PM CST Tue Jan 19 2021
(This evening through Wednesday)
Issued at 252 PM CST Tue Jan 19 2021
It has been a cloudy and raw day across West Central Texas. As of
the 2 PM hour temperatures range from the mid 40s to near 50
degrees across the area. Weak isentropic ascent has resulted in
pockets of light rain and drizzle this morning and
afternoon...although measurable rainfall amounts have been
confined to the northwest Hill Country and Heartland. Meanwhile,
afternoon satellite imagery shows an upper level cutoff low off
the southern California coast, with a plume of Pacific moisture
streaming eastward across northern Mexico and west Texas. Models
indicate a shortwave trough embedded in the southwest flow aloft
approaching the area tonight. The increase in large scale lift
combined with an increase in moisture (PW values greater than 1
inch per forecast model soundings) will lead to precipitation
developing overnight. High res models including the HRRR and
NAMNEST show widespread rain developing after midnight across the
Trans Pecos and northern Edwards Plateau and spreading northward
into the area...with showers then lingering into the afternoon
hours. Thus will continue to carry likely PoPs for much of the
area tonight and tomorrow. The highest rainfall amounts are
expected south of the I-10 corridor, with QPF amounts of around
half an inch to an inch likely across the southeastern half of the
CWA. Otherwise, temperatures will hold in the 40s and lower 50s
tomorrow due to the abundant cloud cover and expected rains.
(Wednesday night through next Tuesday)
Issued at 252 PM CST Tue Jan 19 2021
We are expecting somewhat of a relative lull in precipitation
Wednesday night into Thursday morning. That`s not to say there
won`t be any precipitation at all, but if there is it`s expected
to be isolated and very light in nature.
As we move through Thursday night into Friday morning, the closed
low to the west is still expected to open up into a wave and
generally weaken, but still provide at least a slight chance for
precipitation across most of the area as shortwave energy and lift
move across the southern plains. Warmer temperatures in the 60s
will move back in on Thursday, followed by a weak cold front
Friday, temporarily cooling temperatures into the mid 50s to
lower 60s. Expecting mainly dry conditions Friday into Saturday
morning as well.
For Saturday, the next upper level system will be moving
southeast toward southern Arizona, turning our low level winds
back around to the south, and warming temperatures back into the
60s. Precipitation chances will again be in the forecast from
Saturday afternoon into early next week. However, precipitation
is expected to be fairly light and scattered at best Saturday into
Sunday, with the best chance for significant precipitation Sunday
night into Monday morning. There is relatively low confidence in
these rain chances, and their timing at this time though, so the
forecast should be monitored as we move closer to the weekend.
Temperatures will be warm through early next week.
Issued at 542 PM CST Tue Jan 19 2021
Expect widespread MVFR to low end VFR ceilings this evening. The
ceilings will lower to IFR by 08-09Z at the KSOA/KJCT sites and
then the remainder of the terminals by 16Z. Patchy fog will reduce
vsbys to 2-5SM on Wednesday. Also, light to moderate rain will
move across West Central Texas late tonight through early
Wednesday afternoon. Expect gusty northeast winds to 20 knots this
.PRELIMINARY POINT TEMPS/POPS...
Abilene 38 46 43 65 / 50 70 5 20
San Angelo 38 48 42 65 / 80 80 10 20
Junction 40 50 43 67 / 80 90 20 20
Brownwood 40 48 42 65 / 50 70 5 30
Sweetwater 37 46 45 63 / 40 70 10 20
Ozona 38 47 42 61 / 80 80 20 20