Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/07/21
Area Forecast Discussion
National Weather Service Denver/Boulder CO
739 PM MDT Sat Nov 6 2021
.UPDATE...
Issued at 739 PM MDT Sat Nov 6 2021
IR satellite imagery showing a far amount of high clouds off to
the west. These clouds will progress eastward over Colorado
tonight. This combined with the warm airmass will result in mild
overnight lows. The high clouds decrease Sunday leading to
possible record warmth again Sunday. Going forecast is in good
shape with no changes expected.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 1251 PM MDT Sat Nov 6 2021
Our weekend is off to a record-setting start. With a high of 80F
this afternoon we`ve officially recorded the second warmest
November day in Denver`s history (only 81F on 11/27/2017 was
warmer), and there`s a good possibility tomorrow ends up in a
similar spot. RAP Mesoanalysis this afternoon shows much of
Colorado under 30-45kt of 500mb flow, with very dry conditions
through much of the atmosphere. Not much is expected to change
tonight, though we could see brief mountain wave cloud development
overnight tonight with a pocket of slightly improved moisture.
Tomorrow should be another near-record setting day (78F in 1999)
in the Denver metro area with broad southwesterly flow and very
dry conditions. This will also lead to another day of near-
critical to critical fire danger across our forecast area. Gusty
winds will be likely across the higher terrain, with quiet weather
otherwise.
.LONG TERM...(Sunday night through Saturday)
Issued at 1251 PM MDT Sat Nov 6 2021
After a weekend of balmy temperatures, a cool down is expected for
the work week. A weak upper level disturbance moves through the
southwest flow aloft late Sunday night/early Monday morning with a
cold front expected to move through the eastern plains. Moisture
increases slightly across the area, but low precipitation chances
look like they are confined to the north central mountains with
rain or snow showers possible Monday afternoon and evening. Still
looks pretty dry across the plains, so I have left precipitation
chances out. High temperatures will top out in the mid to upper
50s for the plains Monday. The disturbance moves out of the area
Monday night, leaving the CWA under a weak, transient ridge for
about 24 hours.
Another stronger trof is forecast to move across the northern
Rockies late Tuesday into Wednesday and brings a better chance of
precipitation, especially in the mountains. Could even see some
rain or snow showers farther east across the plains.
By the end of the week, northwest flow aloft dominates the pattern
across the CWA. Some differences crop up in the extended models
with the progression of the upper low over the Great Lakes. Could
see lingering showers across the mountains Thursday, but it will
remain dry on the eastern plains. Expect temperatures to warm
back into the upper 50s and lower 60s across the lower elevations
Friday and Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 739 PM MDT Sat Nov 6 2021
VFR conditions to persist through Sunday with high clouds at
times. Light and variable winds at KDEN and KAPA will turn south-
southwesterly around 03Z. Speeds will be under 15 knots. Winds
late Sunday morning and afternoon should be light and variable. A
weak low moves over eastern Colorado and could bring a wind shift
to the north around 00Z Monday. Wind speeds are expected to stay
rather light.
&&
.FIRE WEATHER...
Issued at 1251 PM MDT Sat Nov 6 2021
Critical fire danger will continue across the warned areas this
evening before winds decrease and humidity increases. Overnight
humidity recovery is expected to be fairly poor, with maximum
humidities between 30-40% overnight. Tomorrow will see another day
of near-record warmth and very dry conditions. Nearly all of our
forecast area will see humidity values below 15% tomorrow
afternoon, except for areas above 9000 feet. Elevated fire danger
will be a common theme across the entire forecast area.
The only question remaining is if winds will be strong enough to
warrant another Red Flag Warning. For now we`ll hold off, but
confidence is increasing that winds will meet criteria across much
of Park County. HREF probabilities of >20kt surface wind peaks at
about 80% tomorrow afternoon across South Park, with the potential
for a few gusts up to 30kt. Elsewhere, winds look light enough to
avoid Red Flag criteria. We`ll hold off on any products this
forecast cycle, but will likely need some sort of highlights by
tomorrow morning.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Meier
SHORT TERM...Hiris
LONG TERM...Stark
AVIATION...Meier
FIRE WEATHER...Hiris
Area Forecast Discussion
National Weather Service Dodge City KS
657 PM CDT Sat Nov 6 2021
...Updated for aviation discussion...
.SHORT TERM...(This evening through Sunday)
Issued at 408 PM CDT Sat Nov 6 2021
GOES-16 visible channels are showing nearly a cloud free sky over
the area with only scattered high cirrus over the northern half of
Kansas into Nebraska associated with the leading edge of an
approaching mid level jet. The area is under strong
ridging/subsidence with a surface trough just to the lee of the
Rockies. With the weak pressure gradient, the surface wind gusts are
limited to around 20-25 knots , and fairly infrequent at that. The
decreasing sun angle should allow temperatures to rapidly cool late
this afternoon from the anomalous warm fall afternoon highs we are
seeing, not only Today but the warmer highs on Sunday as well.
It`s not likely winds drop off to completely light overnight as the
surface pressure gradient increases with a northeastward developing
Colorado surface low. HRRR is indicating areas of 10 to 15 knots
across the area while considerable more mild overnight lows mainly.
in the 40s should be observed by Sunday morning. The lower lying
areas of the far western Ark river valley have the best shot of
seeing lows in the upper 30s.
Warmer temperatures area-wide are expected Sunday afternoon. The
weather in context tool (WPC page) shows the forecast high at about
78 degrees is at the 50s percentile in the MaxT Ensemble violin
plot. The record high is 82.
.LONG TERM...(Sunday night through Saturday)
Issued at 408 PM CDT Sat Nov 6 2021
A pre cold front trough is progged to impact the temperatures by
Monday, as the consensus of the models lay out highs in the low
60s across the smoky hill river valley, while the frontal
boundary, slower to impact the south where highs are forecast in
mid and upper 70s along the Oklahoma line. The cold front will
bring moderate northeast winds into the area during the day, not a
pattern for high wind episodes. The large scale synoptic pattern
remains active with the upper jetstreak carving out a large
negatively tilted trough pattern through the end of the week,
promoting the equatorward plunging of cooler continental air
around the wednesday night timeframe. There may be warm conveyor
belt/isentropic related rain bands out ahead of that system as
well, reflecting the low pops across central Kansas in the
forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 656 PM CDT Sat Nov 6 2021
A surface trough will persist in the lee of the Rockies through
the period, resulting in south winds at 12 kts or less. VFR
conditions can be expected.
&&
.FIRE WEATHER...
Issued at 335 AM CDT Sat Nov 6 2021
We hoisted a red flag warning for Morton county only, through this
afternoon. The winds have been gusting to above 25 mph with
deteriorating relative humidity, and the trend should not change.
The confidence farther north and east is not as great, thus those
counties were not included, however consider elevated fire weather
conditions in the adjacent counties the rest of Today. We will have
warmer conditions on Sunday, although the winds could be a equal
challenge meeting the red flag criterion. At this time no watch is
being posted, however the cimarron grasslands region is still
highlighted by SPC with the elevated category for Sunday
afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 78 45 70 / 0 0 0 0
GCK 41 79 41 68 / 0 0 0 0
EHA 42 85 46 77 / 0 0 0 0
LBL 42 83 44 76 / 0 0 0 0
HYS 43 73 42 63 / 0 0 0 0
P28 43 75 49 75 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Finch
FIRE WEATHER...Russell
Area Forecast Discussion
National Weather Service Lake Charles LA
901 PM CDT Sat Nov 6 2021
.DISCUSSION...
Blanket of stratocu acrs LA has been rapidly diminishing this
evening, leaving clear skies over the area. This has allowed
temperatures to quickly fall since sunset, slightly faster than
hourly temperature grid fcst indicates. Despite this, overnight
lows appear to be on track at the current time, with lows around
40 north to lower/middle 40s south. Conditions still appear to
be favorable for areas of fog/stratus to develop overnight. While
patchy dense fog will be possible in some spots, will hold off on
Advisory at this time given some uncertainty regarding timing and
spatial extent.
Other than adjustments to hourly T grids, fcst is in good shape
this evening. Also, don`t forget that Daylight Saving Time ends
tonight. Be sure to set your clocks back one hour before going to
bed!
24
&&
.PREV DISCUSSION... /issued 556 PM CDT Sat Nov 6 2021/
DISCUSSION...
00Z TAFS.
AVIATION...
MVFR ceilings continue for AEX/LFT, but expected to clear within
the next couple hours, with clearing after sunset at these
terminals. Big concern overnight will be the re-development of
LIFR visibility/ceilings for C and SW LA which will likely give
AEX and LCH terminals in dense fog forming before daybreak. Latest
shortterm guidance continues to show this, thus kept this
inherited forecast. For BPT/LFT/ARA, not showing the dense fog but
with clear skies and calm winds, likely to see some patchy
radiational fog, thus placed the tempo group from 10-14z for MVFR
visibility. After 15z Sunday, visibility and ceilings expected to
improve to VFR with east winds around 5 kts.
DML
PREV DISCUSSION... /issued 335 PM CDT Sat Nov 6 2021/
SHORT TERM [Tonight through Monday]...
Generally dry weather amid a gradual warming trend is expected for
the rest of the weekend into early next week, as high pressure at
the surface and aloft slowly build east into the area.
Cloud cover has proven significantly more stubborn than
anticipated, with roughly the eastern third to one half of the
forecast area still shrouded in stratus. Those pieces of short
range high resolution guidance which have thus far handled this
event relatively well (including the HRRR and NAMNest), do
eventually show clearing taking place during the early to mid
evening hours. Meanwhile, these same models depict another round
of fog/low stratus formation across a good part of the inland
forecast area late tonight, save mainly for coastal SE TX and SC
LA. Given their performance this afternoon along with the
generally favorable synoptic environment (good radiational
cooling), have leaned the forecast in this direction and inserted
patchy to areas of fog in the grids. It should also be noted that
there is also decent agreement with this scenario from numerical
guidance. The fog/stratus is forecast to erode tomorrow morning,
and fingers crossed there is not another repeat of stubbornly
hanging on through the day. Should the clearing occur as expected,
highs tomorrow will climb to around 70.
Fog development is also possible SUN night into MON morning, as
good radiational cooling is once again expected along with some
semblance of a light return flow beginning. Temperatures will also
be not quite as cool, with lows in the lower 40s north to
mid/upper 40s along and south of the I-10 corridor. A more
prevalent southerly flow is expected to develop Monday as the SFC
high shifts a little east of the area, with afternoon highs
gaining another few degrees, topping out in the lower 70s.
13
LONG TERM [Tuesday through Saturday]...
By Tuesday the ridge aloft and at the surface will be shifting into
the southeast states and the north central/northeast gulf coast.
This will allow dewpoints and temperatures to modify into Wednesday
as the flow becomes onshore. A short wave will dig into the southern
plains Wednesday and into the Lower MS Vally Thursday swinging a
cold front through the local area. While most of the support will
remain removed, showers and a few thunderstorms may be possible
Thursday as the boundary moves through. Dry and cool conditions are
expected for next weekend.
05
MARINE...
Light to moderate offshore flow will continue into Monday as high
pressure prevails over the northwest gulf. By late in the day
Monday, a gradual turn to onshore flow will commence as low
pressure develops across the central plains. Rain chances will
begin to increase as a frontal boundary approaches on Thursday.
13
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
718 PM EDT Sat Nov 6 2021
.SHORT TERM...(This evening through Sunday)
Issued at 351 PM EDT SAT NOV 6 2021
Latest RAP analysis and GOES imagery shows a quick-moving, weak
shrtwv passing over the UP this aftn, bringing light, isolated
showers. Drier low levels are prohibiting most of the pcpn, but rain
that does reach the sfc has been light. With an elongated ridge axis
stretching from Texas into New England and a sfc low passing through
northern Ontario, a tighter pressure gradient remains over the UP,
with gusty winds from the SW. Expect these winds to diminish as we
head into the evening. Clouds will exit to the east quickly this
aftn into the evening, with clearing skies expected.
Upstream, a weak ridge and WAA will move over Upper Michigan
tonight. Along this axis, some high-level clouds will briefly pass
over the UP from the SW tonight. Despite the ridge moving overhead
tonight, lighter winds will prevail through the first half of the
night, which should limit some of the potential cooling. Overall, I
went a touch or two under the 50th pctl, with lows near 40 along the
lakes and into the mid 30s inland.
By tomorrow, pressure gradient tightens slightly again between the
ridge axis to the east and a weak sfc low passing through the
Dakotas and MN. With a push of WAA, 850mb temps rise to near +12C;
however, as is usually the case this time of the year, it will
pretty hard to mix up to those temps. A nice breeze from the SW and
sunny skies should allow temps across the west to reach into the
60s, with upper 50s to near 60 central and east.
.LONG TERM...(Sunday night through Saturday)
Issued at 329 PM EDT SAT NOV 6 2021
Quasi-zonal flow across the Upper Great Lakes will result in a
prolonged period of above normal temperatures through midweek before
pattern amplification leads to the development of a late-week fall
storm with increasing pcpn chances and a trend toward cooler than
normal temperatures.
Monday-Tuesday, a shortwave moving well north of the region through
northern Ontario will propel a dry cool front through the U.P. on
Monday. Under partly cloudy skies temperatures will be mostly in the
mid to upper 50s, except for some lower 60s possible south central.
Several models hint at a shortwave moving through the area behind
the cold front Monday night into Tuesday, but with a fairly strong
sfc high pres ridge in place and model soundings showing a dry
airmass would be surprised if there was any pcpn from this feature.
Expect only mid-high clouds with lows Monday night mostly in the 30s
and highs Tuesday in the lower 50s.
A shortwave ridge moves across the area Tuesday night into Wednesday
as the pattern begins to amplify in response to the mid-level trough
deepening over the Rockies and Western Plains. Return southerly flow
ensues Wednesday afternoon behind the sfc ridge axis as pressure
falls begin across the Northern Plains ahead of the upper level
trough. Expect increasing WAA clouds to spread w-e across the fcst
area Wed afternoon which would probably put a lid on any additional
warming. It`s possible an isolated shower could sneak into the
western counties late in the day as the column moistens top-down
under increasing isentropic ascent. Expect highs Wednesday to be
mostly in the lower 50s.
Still plenty of model uncertainty with the evolution/placement of
the upper level and sfc features of the deepening storm system, so
not surprisingly the timing of the system`s cold front is also
uncertain at this time, but most likely it will move through
sometime Thursday. It appears much of the pcpn along/ahead the front
will be rain. Some snow may begin mix in with the rain late Thu
night in the west behind the front
The post-frontal air mass appears will be cold enough to support
lake effect precipitation Friday into Saturday with model consensus
850 mb temps lowering to -8C or colder Friday afternoon into
Saturday. Model uncertainty increases even more for late next week
as the 12Z model runs are trending toward a much deeper mid-level
trough digging across the region with the associated storm system
deepening over the Upper Great Lakes, perhaps over the U.P. or Lake
Superior if the latest GFS and UKMET runs hold true. Will definitely
need to continue to monitor model trends and ensembles over the next
several days as right now there is plenty of uncertainty with how
the lake effect pcpn evolves behind this system, including what the
prevailing wind direction will be.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 710 PM EDT SAT NOV 6 2021
VFR conditions will prevail at all three terminals through this
TAF period, thanks to building ridging. Some mid- to high-level
clouds will move across Upper Michigan, particularly in the latter
half of this forecast period. Expect W-SW winds tonight to become
more southerly tomorrow.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 351 PM EDT SAT NOV 6 2021
Winds relax tonight as a ridge of higher pressure briefly moves over
the lake. Tomorrow, the gradient increases slightly along with
warmer air increasing stability. We should still see some 20 to 25
knots gusts across the east half though. Lighter winds will remain
through the middle of the weak with light ridging remaining over the
lake.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JAW
LONG TERM...Voss
AVIATION...lg
MARINE...JAW
Area Forecast Discussion
National Weather Service Pendleton OR
903 PM PDT Sat Nov 6 2021
.UPDATE...A low pressure system over the ne pacific will continue
to spin moisture into the two state area tonight. Light snow was
falling along the WA cascades that includes at Stampede Pass while
locations such as Trout Lake and Easton hover around the freezing
mark. The hrrr and rap were continuing to show pcpn striking the
WA cascades and further south overnight where a Winter Weather
Advisory remains in effect through Sunday that also includes the
east slopes of the Oregon cascades. Elsewhere some of the moisture
could move further inland and a slight chance of -sn was added to
the forecast for the blues and wallowas tonight. Otherwise a few
showers may drift into the gorge while the remainder of the area
should experience mainly dry conditions. Low temperatures across
the valley are expected to fall into the 30s with 20s across the
higher elevations that also includes central Oregon.
&&
.PREV DISCUSSION... /issued 510 PM PDT Sat Nov 6 2021/
SHORT TERM...Tonight through Monday night...Main concern during
the short term period will be the potential for moderate to heavy
snow in the higher east slopes and along the crest of the
OR & WA Cascades from tonight through early Monday morning.
Another weather system will move into the PacNW tonight, with not
much of a break from last night`s weather system. There are still
numerous showers across the region, and in the forecast area,
especially in the eastern and northeast mountains and over the
Cascades. Have issued a Winter Weather Advisory for the central
and southern Cascade east slopes in WA above 2000 feet for 8-12
inches, and 3 to 6 inches between 2000 and 3000 feet. In OR, an
advisory has been issued for the central and northern Cascade east
slopes (zone 509) at elevations above 2500 feet, which is most of
not all of that zone. However advisory amounts will be reached
between 4000 feet and the crest with 5 to 8 inches expected, and 2
to 4 inches between between 2500-4000 ft MSL. Confidence is high
for these snow amounts over the Cascades.
Showers will become mostly stratiform rain tonight for most of
the rest of the CWA. Then on Sunday, the precipitation will
decrease over the eastern areas, but will continue over the
Cascades, with snow levels around 2500 ft MSL over the OR
Cascades, and around 2000 feet over the WA Cascades by early
Monday morning. Elsewhere in the CWA, precipitation will be light
rain or rain showers. A persistent southwest flow aloft will exist
over the CWA through the short term at the base of a very broad
upper trough that stretches from from the northeast Pacific into
the PacNW. This pattern will send frequent surges of moisture
across the forecast area. There will be a break over most of the
eastern CWA from Sunday morning through the remainder of the short
term period. However, there may still be some rain or snow
showers over the eastern and northeast mountains with little snow
accumulations expected. Snow levels over the eastern and northeast
mountains will be between 1800-2500 ft MSL by early Monday
morning. However, precipitation over the northeast mountains will
be very light. It will be breezy each day, but the winds will
increase much more significantly out of the south with a warm
front by late Monday and Monday night as the warm front moves
northward across the CWA. At this time wind speeds are not
expected to reach criteria for a Wind Advisory on Monday, but this
scenario will need to be watched closely. Temperatures by the NBM
guidance look reasonable with not much variance during the short
term period. Also, model to model and the ensembles do not very
much from each other during the short term period. 88
LONG TERM...Tuesday through Saturday. Active weather pattern
will continue through much of the extended period. On Tuesday, a
warm front will be exiting the area with some gusty southwest
winds before the flow becomes northwest on Wednesday with most of
the precipitation over the mountainous areas. Snow levels on
Wednesday will range from 2100 feet in the central Washington
Cascades to 3400-3800 feet for central and northeast Oregon.
Models are in good agreement with another warm front pushing
north across the area on Thursday and continues through Friday.
This system is tied to ample moisture moving in from the Pacific,
with more significant rain/high elevation snow along the Cascades.
Snow levels Thursday through be rising to above 8 thousand feet,
then starting to lower from the northwest Friday with 6000 feet in
the central Washington Cascades and continued around 8000 feet in
Oregon. This system will continue to drop south across Oregon on
Saturday and weaken with snow levels lowering to 5700 to 7500
feet. While the other model scenarios are similar, there are some
differences in the main push of moisture and the amount of
moisture moving into mainly eastern Washington with the Thursday
system. With the high snow level, will need to monitor for some
hydro concerns on the Schneider Springs burn area. 93
AVIATION...Showers from a departing weather system will linger near
any taf site through 04z that may lower ceilings to bkn050. However
vfr conditions are expected to persist at all taf sites for the next
24 hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 31 51 32 54 / 10 0 0 0
ALW 35 53 36 55 / 10 0 10 0
PSC 37 55 39 56 / 0 0 0 0
YKM 28 50 29 50 / 10 20 20 10
HRI 35 55 34 56 / 0 0 0 0
ELN 29 47 29 47 / 20 20 20 10
RDM 26 47 27 50 / 10 10 10 0
LGD 27 46 28 47 / 30 10 10 0
GCD 27 48 28 51 / 20 0 0 10
DLS 37 53 37 53 / 40 40 40 10
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 4 AM PST Monday for ORZ509.
WA...Winter Weather Advisory until 4 AM PST Monday for WAZ520.
&&
$$
SHORT TERM...97
LONG TERM....93
AVIATION...97
Area Forecast Discussion
National Weather Service Pocatello ID
140 PM MDT Sat Nov 6 2021
.SHORT TERM...Tonight through Tuesday. Early afternoon satellite
imagery was showing a broad complex upper trough extending from WRN
Alaska into the Pacific NW coastal waters with several well defined
short-waves rotating through the flow along with a myriad of smaller
ill defined circulations. Of import for this period is the short-
wave feature rotating into the Oregon coastal waters this afternoon
and the associated moisture streaming NE across NRN California into
SRN Idaho. Numerical models suggest that we should see increasing
upslope flow and precipitation across the CNTRL mountains late this
afternoon as the short-wave reaches the Oregon coast. Attending
moisture will gradually spread east across the remainder of SE Idaho
overnight as the aforementioned disturbance rotates into NW Montana.
Lingering precipitation will continue across the ERN and SE
mountains through the day Sunday before gradually dissipating Sunday
night as the dynamic forcing and moisture supply dry up. Snow levels
will start out around 6500ft MSL in the CNTRL mountains early this
evening before falling to around 5000ft MSL by Sunday morning as a
drier and colder airmass filters into the region behind the
advancing storm system. Across the SE mountains, the transition will
be a little slower with snow levels also starting out near 6500ft
MSL tonight and gradually lowering to 4500 to 5500ft MSL Sunday
afternoon and evening. Snowfall totals for the CNTRL and NE
mountains approach the lower end of Advisory criteria above 8000ft
MSL tonight while the vast majority of the area only records 1 to 4
inches of new snowfall. Hence, we will hold off on any highlights
with this system.
Both the operational GFS and NAM advertise dry conditions across the
region Monday as the low reloads off the NW coast. Here the National
Blend of Models continues to paint a decent swath of precipitation
across the Bear Lake Region with an apparent hat-tip to the ECMWF
solution. Have nudged the precipitation probability lower here
favoring the American operational models. The next storm system
rotates through the base of the low and into the NW coast Monday
night as associated precipitation advances east into CNTRL Idaho
late Monday night and the remainder of SE Idaho Tuesday morning.
This system looks to be slightly cooler with snow levels starting
out near 5000ft MSL in the CNTRL mountains and 5500-6500ft MSL in
the SE mountains and generally remaining steady throughout the day.
Once again, snow accumulations approach Advisory levels in the CNTRL
mountains at higher elevations while the lower levels generally
record 1 to 4 inches of accumulation. Thus, no highlights are
anticipated with this system either. Huston
.LONG TERM...Tuesday night through next Saturday. A very
complicated mess is on hand for this period. The one guarantee is
that it will be wet, continuing the make-up for the dry spring.
However, moisture amounts are wildly different with little
consistency. This results in large forecast temperature ranges for
things such as highs and especially lows, as the dewpoint is a
limiting factor, and it varies strongly. NBM overnight low forecasts
have apparently been abysmal during this period, although most model
guidance has had poor skill; it`s just that the NBM is coming out
the worst. The near term storm for Tue does slip into Tue night and
Wed, and then another storm arrives Thu. After this storm passes, it
appears as though Fri and Sat should be drier, with precipitation
limited to the mountains and highlands. Expect large changes in
magnitudes of precipitation, maximum temperatures, and minimum
temperatures. Wind is expected to stay breezy to windy due to the
two main features, especially Wed and Thu. Messick
&&
.AVIATION...The onset of the "wall" of moisture expected in the time-
height cross sections for each TAF has been delayed by an hour or
two, based on the latest HRRR available and the new 06/12Z NAM.
First, for KSUN, the first affected but it stays rain until late
tonight, then changes over to VCSH as the wind shifts to northwest.
Thus no guaranteed snow at the airdrome. Wind there should be highly
variable with outflow from weak convective cells. Expect only brief
marginal VFR due to CIG. However, the shift to northwest flow does
mean a rapid clearing, likely just before KSUN opens in the morning.
For KIDA, widespread -RA is over by 07/10Z, which will then allow
some IFR CIGs due to moderate to strong upslope flow expected during
the late night hours. KPIH gets enough moisture for some marginal
VFR and breezy conditions, slightly less than KIDA. KBYI will have a
lot of northerly wind due to the location of the surface low, then
shift to the west. The least amount of time spent at marginal VFR
due to CIG is right here, should be up right around the time switch.
Finally, KDIJ is the most affected. The precipitation arrives the
latest, and the 2000ft higher elevation compared to the Snake River
plain makes a huge difference, with snow and IFR very much a
guarantee. The amount of precipitation indicates snow could be good
enough to threaten airport closure due to VSBY, but right now the
lowest forecast is 1SM. Messick
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
605 PM MDT Sat Nov 6 2021
.UPDATE...
Issued at 604 PM MDT Sat Nov 6 2021
Updated forecast to expire Red Flag warning for parts of the
plains. /Hodanish
&&
.SHORT TERM...(This evening through Sunday)
Issued at 349 PM MDT Sat Nov 6 2021
...Critical Fire Weather conditions will be possible this afternoon
over the southeastern plains and areas of the southern I-25
corridor, and be more likely over Huerfano County for Sunday
afternoon, and along the entire I-25 corridor for Monday afternoon...
Today...
A weak upper level ridge is in place with high pressure conditions,
with mostly clear skies and mild temperatures across the entire CWA
again for today. There is a major shortwave trough upstream that is
approaching the region and due to this the mid to upper level flow
will continue to increase out of the SW over southeast Colorado
later in the day. Due to this, as well as a formation of a mesolow
over the lower Arkansas River Valley later this afternoon, winds at
the surface will increase out of the SW through the the passes and
channel outward east of La Veta Pass, and become SSW over the
southeastern plains. With the combination of low RH values later
this afternoon down to around 8 percent for the Walsenburg area in
Huerfano County and 12 percent for Springfield in Baca County, it is
possible that these areas could hit critical fire weather (red flag)
criteria for a few hours, although confidence is not high that it
will be widespread. The HRRR and the RAP13 show a stronger output of
winds for these areas until 23Z for Huerfano County and until 00Z
for Baca County. MESOWEST was already revealing winds and humidities
at criteria from OBs taken right before noon. Therefore the decision
was made to go with an RFW until 6 PM. After this time, winds should
begin to diminish below the threshold. A model blend including
ADJMAV was used in the wind forecast, due to this verifying the best
out of all the models. This does bring up winds again later in the
evening over the far eastern Huerfano, southern Pueblo, and
northwest Las Animas counties above criteria, however, RH recoveries
after sun down will keep the humidities above 15 percent at this
time so it will not be a concern. The downsloping winds will allow
for very warm temperatures over much of the plains this afternoon,
with values topping off in the low to mid 80s for many locations
that are experiencing higher winds, due to compression and mixing in
the lower levels. Colorado Springs has already broke its daily
record and some other areas over the plains could see daily records
broken as well. For all other areas, they will be right around or
slightly above the seasonal average...from 70s elsewhere on the
plains in more wind-restricted areas, to 60s for the high mountain
valleys and SLV, to the 40s and 50s for high country and around 38
for the fourteeners.
Tonight...
Skies becoming mostly cloudy with increasing high clouds throughout
the late evening and overnight due to a Baroclinic leaf associated
with the major shortwave trough upstream. Gusty downsloping winds
will continue to weaken, however, downsloping and mixing winds in
the lower levels will inhibit certain locations over the plains to
not get as much radiational cooling. In the lower Arkansas River
Valley, where it is more wind protected, lows will drop off near the
freezing mark, otherwise lows over the plains will generally be in
the upper 30s and 40s, and 20s to 30s for all high country.
Tomorrow...
The major shortwave upstream will continue to advance towards the
region as a stronger mid level SW`ly flow moves over. This feature
coupled with a slightly tighter pressure gradient at the surface
will bring about the possibility of fire weather conditions and an
issuance of another RFW for areas of the southern I-25 corridor
(Huerfano County, southern Pueblo, northwestern Las Animas counties)
again, as well as eastern Fremont, northwestern Pueblo, and El Paso
counties. As aforementioned, a blend of was included in the wind
forecast due to this verifying the best. HREF ensemble members still
display values only getting close to criteria, however the blend as
brought up the winds to be more reflecting of the areas that will
have a better chance of being impacted by fire weather criteria
winds, along with favorable RH values during the afternoon, and
therefore an overall higher confidence of an RFW issuance after
noon. Otherwise, higher clouds will continue to move out throughout
the day. As it looks, winds should also diminish below criteria by
around 00Z tomorrow again. The downsloping winds will also further
heat up the plains again tomorrow, even slightly warmer from where
they were today. Some areas could top out in the upper 80s and it is
likely if that is the case that more daily records will be broken
over the plains again. Otherwise all other areas of the CWA will be
right around or slightly above the seasonal average.
.LONG TERM...(Sunday night through Saturday)
Issued at 349 PM MDT Sat Nov 6 2021
Main Points:
1)Critical and near critical fire weather conditions are expected
over the I-25 corridor and the western portion of the mountain
valleys on Monday afternoon and Tuesday afternoon.
2) Cooler temperatures through the work week with isolated to
scattered light snow over the Sawatch Range.
Sunday Night through Monday:
Critical fire weather conditions will come to an end around sunset
with RH recovering to greater than 15% across the region, winds are
expected to lessen across the region as the atmosphere begins to
decouple.
Dry conditions are expected throughout the overnight and throughout
Monday across the region. The big forecast issue for Monday
afternoon will be the timing of the expected cold front to propagate
over the plains. Models have slowed down the arrival time of the
front to the later afternoon into the evening, which has a couple
different impacts. The first is that the plains will be warmer than
in previous forecasts and two near critical to critical fire weather
conditions are expected over lee of the eastern mountains and over
the western extents of the mountain valleys (i.e. eastern portion of
the San Luis Valley).
The frontal passage is expected to be dry, with primarily a dew
point increase behind the front and a temperature decrease. The
winds behind the front will be from the northeast with wind gusts up
to 15-25 mph.
Tuesday and Wednesday:
An upper level trough will propagate over southern Colorado on
Tuesday afternoon, which will lead to enhanced wind gusts of around
30 mph over the mountain valleys and the gap flows over the adjacent
plains. Near critical fire weather conditions are possible over the
aforementioned areas, with and emphasis on the southern I-25
corridor, where the RH values will be closest to 15%. As the trough
aloft propagates over central Colorado Tuesday afternoon through
Wednesday morning, definite snow showers are expected over the
Continental Divide. The main trough axis and forcing should begin
midday on Tuesday, but will quickly propagate to the east leaving
residual upper-level northwesterly winds creating an efficient
orientation for orographic snow to continue over the Sawatch
Mountains through Wednesday afternoon. Accumulations will be
relatively light with storm total accumulation around 2" over the
mountains. As that trough axis travels east, expected isolated rain
showers below 6000` and isolated snow showers above 6000`
Thursday through Saturday:
Northwesterly flow continues over Colorado in response to a ridge
located over the eastern Pacific and a broad trough located over the
eastern half of the United States, which will continue isolated to
scattered snow showers over the Sawatch and Mosquito Mountains.
Though the airmass will be dry, the northwesterly component of the
flow will keep the airmass around normal, slightly cool, with values
in the upper 50s to 60s each day.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 349 PM MDT Sat Nov 6 2021
VFR conditions, dry weather, and diurnally driven winds will be in
place throughout the forecast period for all TAF sites. There is an
approaching system upstream that is causing gusty surface winds to
increase out of the S-SW for all terminals for the remainder of this
evening and tomorrow afternoon towards the end of the forecast
period. Due to this, please be advised that there could be some
light to moderate CAT in vicinity of all terminals near the surface
at these times.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HODANISH
SHORT TERM...STEWARD
LONG TERM...SKELLY
AVIATION...STEWARD
Area Forecast Discussion
National Weather Service Sacramento CA
253 PM PDT Sat Nov 6 2021
.SYNOPSIS...
Light rain showers and some high elevation snow showers are
expected today. A wetter weather system is forecast early next
week, bringing widespread rain, mountain snow, and wind.
&&
.DISCUSSION...
Radars across northern California are spinning in precipitation
mode this afternoon as a relatively weak system impacts the
region. A first glance at radar would lead one to believe that
there is widespread light rainfall happening throughout interior
northern California; however, much of this is evaporating before
hitting the ground. As of 2 pm PDT, only a few Sacramento Valley
reporting stations have reported measurable rainfall over the past
12 hours. Expect the majority of realized precipitation to remain
in the foothills and mountains as the afternoon progresses,
leaving very little -- a few hundredths at best -- or no rain for
a good portion of Valley communities. Will note that the HRRR has
been hinting at some potential for isolated convection in the
northern Sacramento Valley. Main impact with this weak storm will
be several inches of accumulating snow near pass level in the
northern Sierra. A Winter Weather Advisory remains in effect
through midnight tonight for locations at/above 6,500 ft.
Today`s system will quickly exit the region overnight with dry
conditions returning with sunshine for Sunday. Highs will remain
about 6 to 12 deg F below early November normals.
Attention then turns to a second wetter system early next week
that will feature rain, snow, and wind. Southerly winds will
increase overnight Monday and into Tuesday morning, becoming gusty
across portions of NorCal. The NBM v4.1 paints a large swath in
the Valley with peak wind gusts between about 20 and 30 mph with
some areas approaching/exceeding 35 mph. These winds will also be
strong in the wind-prone mountain gaps, passes, and ridgetops.
Valley rain amounts right now look to fall in the 0.75 to 1.50
inch range and 1 to 3 inches in the foothills. Snow levels will
start out late Monday with the onset of precipitation around 5,500
to 6,500 ft in the Sierra and 3,500 to 5,000 ft in Shasta County,
but then rise overnight to over 7,000 to 8,000 ft in the Sierra
and 6,000 to 7,000 ft in Shasta County. This makes for a
challenging snow forecast for some of the major passes as a result
of the variable snow levels temporally over the course of the
event and spatially north to south. Precipitation chances begin to
decrease Tuesday afternoon and Tuesday night. // Rowe
&&
.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
A few showers may linger over the northern Sacramento and
adjacent northern mountains Wednesday as the upper level trough
pushes to the east. Ensembles are in good agreement with upper
level ridging building in from the west with dry and warming
temperatures expected for the rest of the week. Ridging should be
strong by the end of the week but may flatten some into next
weekend. Temperatures will remain cool on Wednesday but will warm
to above average by the end of the week, with Valley highs in the
upper 60s to lower 70s projected by the NBM for Saturday.
&&
.AVIATION...
VFR to local MVFR conditions for the northern TAF sites, northern
Sac Valley and mountains through 02Z due to isolated SHRA and
TSRA with BKN to OVC clouds 025-050. VFR conditions at the other
TAF sires with BKN to OVC clouds 070-100 and isolated -SHRA
through 02z. Surface winds remain under 12 knots except over the
higher elevations where gusts to 20 knots will be possible.
Mountain -SHSN with snow levels around 6000 feet AMSL.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight PDT tonight for West
Slope Northern Sierra Nevada-Western Plumas County/Lassen Park.
&&
$$