Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/08/20
Area Forecast Discussion
National Weather Service Bismarck ND
933 PM CST Sat Nov 7 2020
.UPDATE...
Issued at 918 PM CST Sat Nov 7 2020
Important changes for this update involve headlines.
A Winter Weather Advisory has been issued for Divide, Williams,
and Burke Counties late tonight through Sunday night. The main
tipping point for issuing this headline is our assessment that the
GFS and GEFS are warm outliers with their surface temperatures,
which is having a negative impact on model blended solutions. All
deterministic and ensemble model systems that do not implement
the FV3 model core suggest high probabilities of temperatures
remaining below freezing across all of Divide County through
Sunday morning, and possibly in western Divide County through the
entire day. This increases our confidence in impacts caused by
light freezing rain. There is still a chance of snow, and
therefore blowing snow, across the advisory area late Sunday
afternoon through Sunday night, but we think the predominant
hazard will be freezing rain. It is possible that the advisory
may need to be expanded with future updates, but confidence in
freezing rain impacts to the south and east is not as high.
A Dense Fog Advisory has been issued from northwest North Dakota
into the northern James River Valley, encompassing most of the
Highway 2 and 52 corridors. As of 9 PM CST, there were two
predominant areas of dense fog: one from near Williston to Stanley
and another near and to the north and west of Carrington. Rapid
refresh guidance strongly suggests that the dense fog will
continue to fill in and expand spatially, and an expansion to the
advisory may be necessary later in the night. The eastern half of
the Dense Fog Advisory expires at 9 AM CST, when the Wind Advisory
goes into effect. Meanwhile, the Dense Fog Advisory in northwest
North Dakota continues until noon CST Sunday.
UPDATE Issued at 621 PM CST Sat Nov 7 2020
The most significant changes for this update were to increase sky
cover through tonight and add areas of fog across western and
northern North Dakota into tomorrow afternoon. These changes were
made based on observed and rapid-refresh model trends. If both the
values and areal extend of visibility in the HRRR and RAP turn out
accurate, a Dense Fog Advisory will likely be needed. Will wait to
monitor observed trends before issuing one. All other hazards
associated with the strong low pressure system remain on track.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 310 PM CST Sat Nov 7 2020
A complex weather system will impact North Dakota tonight through
Sunday. Currently, dry southwest flow aloft is starting to erode
fog and lower clouds across the south. This trend should continue
through the evening from south to north. As a result will let the
Dense Fog Advisory expire at 3 PM. A surface low then forms
overnight tonight across Wyoming, and pushes eastward into the
Dakotas. As this happens moist northeast flow will be found near
the surface while dry southerly flow continues aloft. The result
looks to be more low clouds, perhaps some patchy fog, and the
potential for widespread drizzle across northern and western
areas. Temperatures will be key tonight as below freezing temps
will result in some areas of freezing drizzle. Current thinking is
these below freezing dips look to come across north central to
northwestern areas. Here a light coating of ice is possible. There
is still some uncertainty not only on precip types but surface
temperatures. As a result will hold off on any winter products for
tonight, although travelers and those outdoors should prepare for
potential slick conditions.
Sunday then continues to be complex as the low become more
developed and stacked aloft. Flow aloft becomes quite strong and
generally south to southeastward. This brings warm and somewhat
dryer air to the region. This briefly ends any sort of wintry mix
during the day, while bringing increased winds to the state. As a
result have enough confidence to issue a Wind Advisory across the
CWA. As a cold front swings through the state throughout the day
Sunday, scattered to widespread rain showers look to develop.
There is some weak instability and a lot of shear across the
region. This could lead to some low topped thunderstorms across
the region. Main threat will be strong winds from these storms, as
pulling down strong winds aloft could easily create severe/high
wind criteria gusts. Temperatures for the most part will be mild
for one more day on Sunday in this southerly flow. The exception
will be in the northwest where near normal temps are expected.
.LONG TERM...(Sunday night through Saturday)
Issued at 310 PM CST Sat Nov 7 2020
Active weather looks to start the long term, then conditions
become cool. Sunday night still looks to see a period of rain
changing to snow, with perhaps some freezing rain during the
transition. Best chances for accumulating snow still looks to come
in the northwest where 1 to 3 inches look possible Sunday night
through the end of the day Monday. Today`s forecast may have
slightly lowered snow accumulations as the overall low track has
shifted slightly westward. There still remains uncertainty to
track and precip types, so have held off on any winter products at
this time. This snow could linger in the northwest during the day
Monday. There are some indications as the trough and cold front
move eastward Monday there could be some rain or snow across
eastern portions of the CWA. This is a bit of a change and
confidence in this is low at this point, and for the most part not
in the forecast. Breezy conditions may also continue for Monday.
Precipitation ends Monday evening. The rest of the long term looks
to be in a general trough pattern, although with limited chances
for snow. The main story for the remainder of the long term will
be the return of near to below normal temperatures. Low
temperatures look to be in the teens while highs look to only be
in the 20s to 30s, with perhaps a slight increase in temperatures
by the end of the long term period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 621 PM CST Sat Nov 7 2020
There are multiple aviation hazards through this forecast period
as a strong low pressure system moves from southwest to north
central North Dakota on Sunday.
This evening through tonight, IFR to LIFR ceilings and visibility
are expected to continue at KXWA and KMOT, and will likely
redevelop at KDIK. There will likely be a slow improvement in
conditions throughout the day Sunday. Drizzle is also possible
at KXWA and KMOT Sunday morning. Chances for rain and snow will
then increase at KXWA Sunday afternoon. Elsewhere, expect a chance
of light rain with a few thunderstorms possible Sunday afternoon.
Strong winds are expected on Sunday, with sustained speeds
reaching 25 kts and gusts to 45 kts at times. Wind direction will
vary greatly as the center of the low crosses the state. There are
low level wind shear concerns at KBIS and KJMS tonight until late
Sunday morning.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 9 AM CST /8 AM MST/ Sunday to midnight CST
/11 PM MST/ Sunday night for NDZ019>023-025-034>037-042-045>048-
050-051.
Wind Advisory from 3 PM CST /2 PM MST/ Sunday to midnight CST
/11 PM MST/ Sunday night for NDZ001>005-009>013-017-018-031>033-
040-041-043-044.
Dense Fog Advisory until noon CST /11 AM MST/ Sunday for NDZ001-
002-009-010-017.
Dense Fog Advisory until 9 AM CST Sunday for NDZ011>013-021>023-
025.
Winter Weather Advisory from 3 AM Sunday to 6 AM CST Monday for
NDZ001-002-009.
&&
$$
UPDATE...Hollan
SHORT TERM...Anglin
LONG TERM...Anglin
AVIATION...Hollan
Area Forecast Discussion
National Weather Service Denver/Boulder CO
839 PM MST Sat Nov 7 2020
.UPDATE...
Issued at 838 PM MST Sat Nov 7 2020
We added eastern Boulder County and the Denver metro area to the
High Wind Warning tonight and tomorrow morning as short range
model output are now showing much stronger gusts in these areas.
Maximum gusts are expected to exceed 50 knots and be associated
with scattered passing convection, where any showers or virga will
mix strong winds down to the surface quickly. The latest 00Z NAM
shows 70 knots of wind at 700 mb around 09Z, so it won`t take much
momentum transfer to deliver those high winds.
The record high minimum temperature at KDEN is still in jeopardy
tonight with temperatures not expected below 48 F until a few
hours after midnight. We adjusted maximum temperatures down
slightly across the area tomorrow to better align with more recent
guidance.
Wind and humidity on the plains east of the Denver metro will
approach criteria for a Red Flag Warning for a few hours tomorrow
afternoon. There is currently not enough confidence that these
conditions will develop or hold for a minimum of 3 hours to issue
a warning, but the situation will need to be reevaluated
overnight or in the morning.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 129 PM MST Sat Nov 7 2020
A potent but quick burst of snow and wind is still expected to
develop late tonight into Sunday morning. The models show a strong
jet max rounding a trough after midnight. The strongest winds at
that time will be over the eastern plains. Any weak showers/virga
that develops could mix stronger gusts to 50-55 kts could mix
the surface. Consequently, no changes to the current high wind
warning at this time. Could see a record high min for this date.
The record is 48, but with the gusty winds this evening the
temperatures at D.I.A is not expected to drop below 50 before
midnight. In the mountains. the models still showing a brief but
potent burst of snow developing. Best combination of snow/wind
looks like it will be in zone 34, moving from southwest to
northeast across the mountains. The HRRR shows some strong winds
gusts in excess of 60 kts above timberline after 09z. Have decided
to issues a winter weather advisory for zone 34 where the best
combination of snow and wind will likely occur. There will be a
period of weak mid level qg omega until 09z, then moderate to
strong qg decent kicks in as strong bora winds develop. Sunday,
the snow and wind will persist until 15z in the mountains than
taper off through the day. It will be closer to seasonal
temperatures on Sunday.
.LONG TERM...(Sunday night through Saturday)
Issued at 315 PM MST Sat Nov 7 2020
Strong southwesterly flow aloft is expected for the CWA Sunday
night. It will decrease gradually after midnight into Monday
afternoon as an upper trough axis moves eastward into Colorado.
The upper trough is progged to be over the CWA Monday afternoon
through about midnight Monday night. By Tuesday morning weak to
moderate northwesterly flow is is place for us. The flow aloft
becomes zonal by Tuesday afternoon and remains that way through
Tuesday night. The QPF fields show fairly strong upward vertical
velocity for the CWA Sunday night through Monday evening. Decent
subsidence is in place the rest of Monday night and Tuesday.
Weaker, more neutral synoptic scale energy is in place the rest
of Tuesday and Tuesday night. The low level pressure and wind
fields show somewhat normal drainage wind patterns for Sunday
night. A cold front moves south across the CWA later Sunday night
into Monday morning. Fairly decent north-northeasterly low level
upslope winds are progged early Monday morning into Monday
evening. Weak normal diurnal wind trends are expected later Monday
night through Tuesday night. For moisture, there is some progged
to move into the mountains Sunday night with the incoming upper
trough. Moisture increases over the plains as well during the day
Monday. The best moisture for the CWA will be from 21Z Monday to
09Z Tuesday. It will decrease from west to east Monday night.
Tuesday and Tuesday night are pretty dry in most areas with a bit
of moisture expected over the high mountains, especially over the
northwestern CWA. The mountain top winds are southwesterly and not
too strong; so orographic enhancement does not look very good.
For the plains, the best moisture is Monday afternoon and evening.
There will also be some upslope winds during that time, although
not very deep. Pops look "likely" in the high mountains late
Sunday into Monday evening, and for the plains, "chance"s look
good mainly Monday afternoon and night. Snowfall may be high
enough to warrant "advisory" criteria amounts in zones 33 and 34
on Monday into Monday evening. Will keep monitoring at this time.
For temperatures, readings will actually be below seasonal normals
both Monday and Tuesday. For later days, Wednesday through
Saturday, models have a broad upper level trough over the CWA
Wednesday into Thursday with moderately strong zonal flow aloft.
There is a brief shot of upper ridging for the rest of Thursday
into Friday, with more upper troughing later Friday into Saturday.
The ECMWF shows higher amplitude troughing compared to the GFS.
There is not a lot of moisture to work with during the later
periods. Temperatures should stay below seasonal normals, however
they will warm slowing through the week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 838 PM MST Sat Nov 7 2020
After a brief lull this evening, winds were beginning to increase
as low and mid level gradients tightened. That trend should
continue through 09Z, but then a blast of even stronger winds with
gusts of 45-50 knot swill be possible for a brief time between 09Z
and 12Z. That would be associated with passing weak showers and
the cold front. Behind the front, winds should settle down a
little and be from the west/southwest through most of Sunday.
Expect gusts generally to around 30 knots off/on through the day.
Then winds become lighter by 00Z-01Z Monday (early Sunday
evening), VFR conditions expected, even with the passing showers.
There is a chance blowing dust could briefly reduce visibilities
if the stronger winds closer to 50 knots materialize overnight.
&&
.FIRE WEATHER...
Issued at 838 PM MST Sat Nov 7 2020
Southerly winds of 25-35 mph sustained with gusts in the 45-60
mph range are expected after midnight. The strongest gusts should
occur south of I-76. Little in the way of wetting precipitation is
expected overnight across the plains, but mountains will get
wetting snow (starting with rain in valleys).
Dry downslope winds will develop behind the cold front late
tonight and early Sunday morning. Humidities will drop to around
15 percent over the plains despite the cooler temperatures. There
is currently not enough confidence that Red Flag conditions will
develop or hold for a minimum of 3 hours to issue a warning, but
the situation will need to be reevaluated overnight or in the
morning.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from midnight tonight to 8 AM MST Sunday for
COZ039>041-045>051.
Winter Weather Advisory from midnight tonight to 10 AM MST
Sunday for COZ034.
&&
$$
UPDATE...Direnzo
SHORT TERM.....Coop
LONG TERM......Koop
AVIATION...Barjenbruch
FIRE WEATHER...Coop/Barjenruch
Area Forecast Discussion
National Weather Service Dodge City KS
437 PM CST Sat Nov 7 2020
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Sunday)
Issued at 1222 PM CST Sat Nov 7 2020
The upper level pattern to start the short term period is rather
amplified, with a deep trough over the west coast states and a
ridge over the eastern CONUS as per RAP analysis. The upper level
trough, with multiple shortwave impulses embedded within, will
move slowly east allowing surface lee cyclogenesis to occur in
the eastern WY. This will tighten the surface pressure gradient
across southwest KS today bringing very strong southerly winds
sustained in the 25-35 mph range with 45+ mph gusts possible.
Afternoon highs will range from the low to mid 70s, with some
upper 70s possible west of a Scott City-Johnson City line. Despite
more than adequate forcing and plenty of low-level moisture, the
mid and upper levels will be quite dry which should keep our skies
mostly clear today. Overnight, persistent south winds will keep
lows in the low to mid 50s.
Monday night through Sunday morning, the first shortwave impulse
embedded within the upper trough will eject northeast into the
northern plains as a secondary impulse dives south behind it out
of western Canada. This will pull the surface cyclone into the
northern plains as well. However, the surface pressure gradient
over southwest Kansas will remain tight, and strong south winds
will persist through Sunday. Expect more highs in the mid 70s
Sunday afternoon with mostly clear skies.
.LONG TERM...(Sunday night through Saturday)
Issued at 209 PM CST Sat Nov 7 2020
At the beginning of the long term period, the secondary shortwave
impulse will be rounding the base of the larger upper level trough
centered over the Great Basin. As this impulse ejects eastward Monday
morning, a secondary surface low pressure center will develop in
eastern Colorado. This will lead to another windy day over our
area with sustained winds over 25 mph likely. Highs on Monday
should still reach into the low 70s before a cold front associated
with the surface cyclone pushes through the area late Monday
afternoon. Weak instability and plenty of synoptic forcing should
foster the development of showers and thunderstorms along/just
ahead of the frontal boundary. Behind the front, strong
northwesterly winds will advect much colder air into southwest
Kansas, and a brief period of wintry mix/snow cannot be ruled out
early Tuesday morning mainly in the northern half of our area.
Any lingering precipitation Tuesday morning should clear out by
the afternoon as weak surface high pressure builds into the
central plains bringing relief from the strong winds. Upper level
west-southwesterly flow will become established over southwest
Kansas as the longwave upper trough sits over the majority of the
CONUS. Afternoon highs will range from the upper 40s near I-70 to
the mid 50s near the KS/OK border.
Beyond Tuesday, predictability begins to decline as medium range
guidance begins to differ in the placement of large scale
features. In spite of this, the weather is expected to be quiet
and dry for the remainder of the long term period with typical
fall temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 433 PM CST Sat Nov 7 2020
VFR conditions for the entirety of the period for all TAF sites
under the influence of upper level northwest flow and leeside
troughing across eastern Colorado. Skies will remain mainly clear
with strong south winds gusting up to 35kts through the entirety
of the period due to continued mixing of the boundary layer
overnight with an intense low level jet ahead of a cold front that
will affect the CWA after the end of the period overnight into
Monday morning. Otherwise, no other weather elements are expected
at this time.
&&
.FIRE WEATHER...
Issued at 1254 PM CST Sat Nov 7 2020
Strong south winds will intensify further later today as a lee
trough in eastern Colorado deepens. Concurrently, low relative
humidities in the 20-30% range are likely near the Colorado border
despite recent moist advection. These factors will foster elevated
to near-critical fire weather conditions near the Colorado border.
These conditions will relax after sunset as the boundary layer
begins to cool and relative humidity increases.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 74 57 71 / 0 0 10 10
GCK 51 74 53 69 / 0 0 10 0
EHA 50 75 52 69 / 0 0 0 0
LBL 49 76 53 71 / 0 0 10 0
HYS 55 74 57 70 / 0 0 20 20
P28 54 75 58 70 / 0 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Springer
LONG TERM...Springer
AVIATION...Lowe
FIRE WEATHER...Springer
Area Forecast Discussion
National Weather Service Hanford CA
418 PM PST Sat Nov 7 2020
...Updated Air Quality Issues Section...
.SYNOPSIS...Rain and mountain snow is expected across the entire
on Sunday the first major storm system of the season impacts the
area. Low temperatures will approach the freezing mark in the San
Joaquin Valley and drop below the freezing mark in the Kern
County Deserts on Monday, Tuesday and Wednesday mornings.
Temperatures will remain below normal next week.
&&
.DISCUSSION...A large upper low pressure system and associated
cold front pushed across central CA today bringing much cooler
temperatures and mainly light precipitation to our area today. A
few thunderstorms have even been observed in southern Kern County.
HRRR indicating a stronger low pressure system will drop southward
through our area on Sunday bringing widespread precipitation to
our area. Much of the Sierra Nevada will pick up an additional
half inch to and inch of liquid precipitation with the snow level
lowering to around 3000 feet by Sunday afternoon. A Winter Storm
Warning remains in effect for the Sierra Nevada through Sunday
evening where 4 to 8 inches of additional snowfall are likely
above 4000 feet for the first significant winter storm of the
season. Further south in Kern County, a Winter Weather Advisory
remains in effect for the Kern County Mountains through Sunday
evening where 2 to 4 inches of additional snowfall are likely over
the higher peaks and up to 2 inches are possible near the
Grapevine and Tehachapi passes, potentially adversely impacting
travel Sunday afternoon and evening. In addition, a brief period
of gusty downslope winds will be possible Sunday afternoon and
evening in the Kern County Deserts.
This system is expected to move to the east of our area Sunday
night and Monday. The models are trending slightly faster with
the departure of this system and along with clearing skies and
diminishing winds across our area. This will allow for radiational
cooling to take place on Sunday night and as a result, low
temperatures across much of the San Joaquin Valley will drop
below the freezing mark on Monday morning and into the mid 20s in
the Kern County Deserts. Since this is expected to be the first
hard freeze of the season in the Kern County Deserts a Hard Freeze
Watch has been issued for later Sunday night and Monday morning
while a Freeze Watch has been issued for the San Joaquin Valley
for the same time period.
A cool and dry northwest flow is expected to prevail over our
area for much of next week with dry conditions and below normal
temperatures continuing through at least Thursday. Sub-freezing
temperatures will be possible again across the San Joaquin valley
and Kern County Deserts on Tuesday and Wednesday mornings as the
prevailing cold airmass only warms slightly by midweek.
The medium range models are trending further northward with a low
pressure system moving across the PAC NW and Norcal next Friday
and Saturday. This system has the potential to bring some light
precipitation to our area mainly from Fresno County northward.
Daytime temperatures are expected to remain below seasonal
normals through next weekend.
&&
.AVIATION...Widespread mountain obscuring IFR in the Sierra
Nevada, Sierra foothills and Tehachapi Mountains due to low
clouds and precipitation. Areas of MVFR with local IFR in low
clouds and showers in the San Joaquin Valley and west side hills.
Otherwise, VFR conditions are expected across the the central CA
interior for the next 24 hours.
&&
.AIR QUALITY ISSUES...
None.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
an/or to provide feedback.
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 PM PST Sunday for CAZ195>197.
Hard Freeze Watch from late Sunday night through Monday morning
for CAZ198-199.
Winter Storm Warning until 10 PM PST Sunday for CAZ192>194.
Freeze Watch from late Sunday night through Monday morning for
CAZ179>189.
&&
$$
public...DS
aviation....DS
weather.gov/hanford
Area Forecast Discussion
National Weather Service North Platte NE
629 PM CST Sat Nov 7 2020
.SHORT TERM...(This evening through Sunday night)
Issued at 257 PM CST Sat Nov 7 2020
The main concern in the short term is with strong winds tonight into
tomorrow. Looking at bufkit soundings there is some concern that we
will not see as good of mixing overnight, as several models are
indicating that the inversion will be rather strong tonight keeping
it from mixing. However there are still a few models hinting that
the inversion may be weak and decent mixing will occur. Almost all
models have been showing strong winds just off the surface up to 850
mb, generally around 25 to 40 kts. The RAP and HRRR have 60+ knots
from 850 to 800 mb. At this time forecaster confidence remains low
on seeing the mixing however as the RAP tends to have a better
handle on mixing than some of the other models and it is one of the
models showing the inversion holding on through the night not
allowing the strongest winds to mix down. This would create gust
at the surface around 50kts up to 60kts. Since confidence
continues to remain low as the uncertainty of the inversion
strength looms, decided to only expand our High Wind Watch and not
upgrade to a High Wind Warning at this time.
Temperature will remain very mild for this time of year. In fact,
low temperatures tonight are expected to be 25 to 30 degrees above
normal. Temperatures could possibly remain even slightly warmer IF
we are able to mix tonight as 850 temps around 10 to 15 degrees
celsius, however confidence is low in this occurring.
As a cold front passes through late Sunday there will be a chance
for precipitation ahead of the front. At this time precipitation
mode should generally be rain showers. SPC does have us outlooked
for general thunderstorms but the better environment for
thunderstorm development looks to be east of the CWA, however if a
rumble of thunder did occur it would generally be east of highway
183.
.LONG TERM...(Monday through Saturday)
Issued at 257 PM CST Sat Nov 7 2020
Much colder air is in store for Monday as this will end our streak
of well above normal temperatures. Highs on Monday will generally
be in the 30s and 40s as the front continues to move through the
area. A trof then moves through Monday night brining snow chances
to the area. A this time the best chances for snowfall will
generally be across the southern and eastern portions of the CWA.
After Tuesday temperatures will be near normal with highs in the
40s, with no precipitation chances through Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 624 PM CST Sat Nov 7 2020
Low-level wind shear will be a concern tonight into Sunday morning
as very strong southerly winds will be just above the surface.
Otherwise gusts greater than 35 kt likely at the surface. VFR will
prevail with SCT to BKN mid and high level clouds.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from midnight CST /11 PM MST/ tonight through
Sunday morning for NEZ004-005-022>025-035>037-056>059-069>071-
094.
High Wind Watch from 3 AM CST Sunday through Sunday afternoon
for NEZ006>010-026>029-038.
&&
$$
SHORT TERM...Gomez
LONG TERM...Gomez
AVIATION...Taylor