Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/24/22
Area Forecast Discussion
National Weather Service Birmingham AL
801 PM CST Wed Nov 23 2022
...New SHORT TERM...
.SHORT TERM...
(Tonight through Thursday)
Issued at 748 PM CST WED NOV 23 2022
Temperatures are not falling as quickly this evening as previous
two nights as winds have become southeast several thousand feet
above the surface. The most interesting feature this evening is a
large area of low clouds moving westward across south Georgia. The
RAP model is the only model that seems to have a handle on the
moisture advection. The clouds will likely reach those
Alabama/Georgia state line around midnight, mainly impacting
areas along and south of I-85. The RAP has the clouds advancing
into most of east Alabama by sunrise Thursday. The moist layer is
too shallow for any raindrops, so no rain expected. Given the warm
temperatures experienced today, raised highs tomorrow a few
degrees most areas. Rain with the next system still not expected
into west Alabama until Thursday evening.
58/rose
Previous short-term discussion:
(This afternoon through Thursday)
Issued at 1133 AM CST WED NOV 23 2022
Surface high pressure over the east coast will continue to weaken
and move east today. Flow will become somewhat northerly this
afternoon with drier air advecting in and skies clearing becoming
partly cloudy for much of the day. Overnight...flow will shift to
out of the south and southwest...bringing more moisture and warm air
advection ahead of an approaching frontal boundary. PW values will
slowly increase from the 0.50 average to around 1.00 inches through
the day on Thursday with cloud cover increasing tonight through
Thursday. With mostly cloudy skies Thursday... temperatures will be
near the same as they will be today. Rain is expected ahead of this
front late Thursday with light showers possible in the late
afternoon and early evening. The models have trended slightly slower
with timing for the rainfall...so have left a slight chance for the
far west in the forecast before 7 pm. Most of the rain should move
through beginning in the evening through the rest of the night. High
temperatures today will be in the mid 60s to lower 70s. Low
temperatures tonight will be in the 40s. High temperatures tomorrow
will be in the upper 60s and lower 70s.
24
&&
.LONG TERM...
(Thursday night through next Tuesday)
Issued at 215 PM CST WED NOV 23 2022
Widespread rainfall, north of a warm front to our south, will end
through the day on Friday. A surface low along the front struggles
to push northward, and expect thunder to remain elevated Thursday
night and Friday. A break in widespread rainfall is expected
Friday night and into Saturday, before the upper low rotating over
western Texas moves eastward toward the Mississippi River Valley.
Most of the rainfall will hold off until Saturday afternoon.
Cannot rule out thunder, but instabilities are weak. Did increase
gradient winds Saturday and Sunday, with some gusts up to 20-25mph
possible.
Adjustments were made to account for timing changes with the
arrival and departure of rainfall, and increase in wind speeds.
Otherwise, extended forecast is on track.
14
&&
.AVIATION...
(00Z TAFS)
Issued at 513 PM CST WED NOV 23 2022
Minimal cloud cover thru 06z due to a dry air mass is place across
Alabama. A low level easterly flow over Georgia will advect higher
moisture into east Alabama overnight. Cigs arnd 2000 ft agl over
east Georgia will move into far east Alabama arnd 06z and to near
the I-65 corridor by 12z. The MVFR cigs will slowly lift after 15z
and become VFR by 18z. Light rain will enter far west Alabama by
the end of the period with rain overspreading central Alabama
Thursday night.
58/rose
&&
.FIRE WEATHER...
South to southeasterly winds will set up tonight increasing cloud
cover and moisture slowly through the day tomorrow. Rain chances
return Thursday late afternoon and evening. through Friday morning.
A break in the rain is expected Friday evening and into Saturday
morning, before another system moves through the area, with rain
chances through Saturday night.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 40 68 47 64 / 0 10 90 60
Anniston 45 68 51 65 / 0 10 90 70
Birmingham 47 69 53 65 / 0 10 90 60
Tuscaloosa 47 70 54 66 / 0 10 100 50
Calera 47 69 54 65 / 0 10 90 60
Auburn 50 66 54 65 / 0 10 80 70
Montgomery 48 71 56 68 / 0 10 80 60
Troy 49 71 56 70 / 0 10 70 60
&&
.BMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...58/rose
LONG TERM....14
AVIATION...58
Area Forecast Discussion
National Weather Service Pueblo CO
601 PM MST Wed Nov 23 2022
.UPDATE...
Issued at 600 PM MST Wed Nov 23 2022
Expired the Red Flag Warning. Humidity should increase above
critical thresholds quickly this evening, although gusty winds
will likely persist in some areas for a few more hours at least.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 238 PM MST Wed Nov 23 2022
Key Messages:
1) Snow is expected to over and near the higher terrain tonight and
continue through Thanksgiving Day. For the high country and the
Palmer Divide, light to moderate snow accumulations are expected.
2) Highest snow accumulations and dangerous travel conditions are
expected in our southern Sangres and the Raton Mesa, where a Winter
Weather Advisory has been issued.
Currently..
Water vapor imagery shows the base of a deep trough pushing into
western Colorado this afternoon, where a low is expected to close
off over the next several hours. Extremely dry air is being pumped
into region ahead of this system, with strong westerly drainage
winds pushing through all of our usual gap flow prone areas as well.
This set up is leading to critical fire weather conditions for the
middle Arkansas River Valley and the southern I-25 corridor, where
relative humidity values have plummeted into the single digits. A
weak preceding surface trough has pushed through, bringing a
northerly wind shift to northern El Paso county. The Air Force
Academy is currently seeing 21 mph northerly winds which has
brought their dew point up several degrees this hour. MRMS shows
light snowfall starting to push into Lake County.
Tonight..
The HRRR brings our main cold frontal boundary into northern
portions of Teller and El Paso county around 7pm this evening.
Northerly winds are expected to gust up to 30 mph behind this
boundary, persisting through the overnight hours. Snow continues to
push into the Continental Divide region overnight tonight, with
steady snow beginning around midnight for our Southern Sangres. A
Winter Weather Advisory has been issued for this region, along with
the Raton Mesa, from midnight tonight until tomorrow evening, with
snow accumulations of 5 to 10 inches expected across the southern
Sangres and into Raton Pass and 2 to 6 inches expected across the
southern I-25 Corridor. Snow fall across the Pikes Peak region and
the Palmer Dvd could range from 1 to 4 inches, greatest across
northeastern Teller County and northwestern El Paso County. We are
not expecting much, if any, accumulations in Colorado Springs or
further south across southern El Paso County into Pueblo County or
the rest of the southeast plains. The rest of the higher terrain and
southern and western portions of the San Luis Valley could see a few
inches of snow as well.
Tomorrow..
Snow continues for most of the high country throughout the day
tomorrow, clearing from northwest to southeast through tomorrow
afternoon. For the Palmer Divide, expect wind driven snow to begin
any time after midnight, increasing in intensity during the early
morning hours. This will make for hazardous driving conditions on I-
25 for our Thanksgiving Day travel plans. Though snow amounts are
not expected to be high, visibilities will be low at times, with the
northerly winds gusting up to 40 mph through the day. Wind chills
will likely be in the single digits for most of El Paso county from
about 2am until 11am tomorrow morning. Daytime highs are expected to
get up into the low to mid 40s tomorrow for the lower Arkansas River
Valley, with 30s elsewhere on the plains. Mountains and mountain
valleys are expected to stay in the 20s and 30s as well.
For our southern Sangres and the Raton Mesa, to include the southern
I-25 corridor, snowfall is expected to increase in intensity as
upslope deepens, mainly from about 3am until noon tomorrow.
Northerly wind gusts of 40 to 50 mph are also expected for this time
period, which will likely lead to dangerous travel conditions,
especially through Raton Pass. Snow begins to taper off through
tomorrow afternoon, with drier air moving in after sunset tomorrow
evening.
A few areas of highest uncertainty with this forecast period will be
for the Wet Mountains and southern and western portions of the San
Luis Valley. Both of these areas could potentially see higher than
currently forecast snow amounts, mainly due to potential snow bands
setting up in the deformation zone later tonight and into Thursday
morning. A slight shift towards a more easterly wind direction later
tomorrow morning could also lead to enhanced upslope snowfall for
the Wets.
jme/mw
.LONG TERM...(Thursday night through Wednesday)
Issued at 238 PM MST Wed Nov 23 2022
Key messages:
1) Some lingering snow showers will occur over the southern Sangre
de Cristo Mountains, Raton Mesa area, and southeastern plains
Thursday evening through Friday morning. A few snow showers will be
possible late afternoon/evening on Friday over southeastern Baca
County.
2) Much warmer initially on Saturday, then a cold front will move
through late morning/afternoon over the plains, with a few snow
showers possible over the central mountains Saturday evening through
early Sunday morning.
3) After a cooldown on Sunday, there will be a slight warmup Monday
ahead of the next low pressure system that will bring much colder
temperatures and snow possibly for all of southeast Colorado next
Tuesday through Wednesday.
Detailed discussion:
Thursday night through Friday...
As the major shortwave tough with an associated U/L closed low at
the 500 mb level continues to move south over New Mexico, so will
the precip. Upsloping will help to keep some snow over the Raton
Mesa area, as well as the southern Sangre de Cristo Mountains into
the early morning hours on Friday. There will also be some snow, and
a rain/snow mix continuing over the southeastern plains from the
deformation zone. The NNW`ly winds will advect in some much cooler
temperatures in so lows will be about 10 degrees colder under
clearing skies with a brisk wind, and produce wind chill values in
the single digits over parts of the eastern plains, as well as
eastern El Paso County. Lows will drop into the teens over most of
the plains, and into the single digits for a good part of high
country. Some lower level clouds and patchy freezing fog may develop
in the San Luis Valley into early Friday morning, especially in
close proximity of the Rio Grande riverbed.
On Friday, high pressure will continue to build back in behind the
exiting trough and allow for temperatures to rebound nicely back
into mostly 50s over the plains and right back to near seasonal
values. As the low to the south begins to retrograde back to the
north a bit, some wrap around moisture of the deformation zone could
catch the very far southeastern plains (mainly the southeastern half
of Baca County) and result in a few snow showers by later in the
afternoon and evening. However, much of the latest model guidance
keeps this south of Colorado. The remainder of the CWA will remain
dry.
Saturday through Sunday...
There will be an approaching mid to upper level wave approaching the
region. Initially, downsloping winds out of the west will help warm
up the plains and lower mountain valleys considerably in the
morning, with most locations getting above the average seasonal
temperature for this time of year. A cold frontal passage will occur
by later in the morning and afternoon over the plains and shift
winds to a NNE`ly direction with colder air advection in behind it.
The timing of this front moving through at this time appears to be
somewhere between 11 AM and 1 PM over the plains of the northern
half of the CWA, and around noon to 2 PM over the southern half. As
the axis of the wave continues to move over by later in the evening,
the mid level instability, along with a saturated layer above the
700 mb level, will produce a few snow showers over the central
mountains.
On Sunday, the cooler air advected in from the north will knock down
high temperatures right back around the seasonal temperature for
most locations. As a ridge temporarily builds in behind the exiting
trough and ahead of the next major shortwave upstream, it will allow
for mostly clear skies and no precip expected anywhere in southeast
Colorado.
Monday through Wednesday...
Deterministic models and ensembles alike are is relatively close
agreement with another major shortwave trough propagating over the
region throughout this timeframe in the forecast period. The ECMWF
has the most amplification with the trough with a slightly more
positive tilt to it, whereas the GFS and the Canadian are in closer
agreement with the position and slightly quicker progression. The
GFS also has the precip beginning the soonest over the Continental
Divide during the late evening hours on Monday, with a surging cold
front associated with it moving in during the early morning hours on
Tuesday. This will likely produce some snowfall over the Palmer
Divide around that time, and then move south with better chances of
snow over the plains by later in the day on Tuesday. This system
will bring in much colder air behind it, with some of the ensemble
members suggesting highs in the low 20s for Colorado Springs on
Tuesday. It is still too far out in the forecast period to know
which model is most reliable, and is something that will need to be
more closely monitored in the upcoming days. -Stewey
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 238 PM MST Wed Nov 23 2022
A potent upper trough will dig across southern Colorado tonight
and continue to move south into central New Mexico through the day
on Thursday, bringing snow and blowing snow to the southern mts
late tonight and Thursday. While the Palmer Dvd will see some
snow, strong northerly winds developing at COS and PUB this
evening will likely keep VFR cigs and little to no precipitation
expected at both terminals through the taf period.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from midnight tonight to 5 PM MST
Thursday for COZ074-075-087-088.
&&
$$
UPDATE...GARBEROGLIO
SHORT TERM...EHR/MW
LONG TERM...STEWARD
AVIATION...MW
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
730 PM MST Wed Nov 23 2022
.UPDATE...
Issued at 730 PM MST Wed Nov 23 2022
Current surface analysis has cold front east of the forecast area,
with brisk northwesterly winds lingering behind it across the
region. Upper level analysis shows large scale trough over the
Rockies, with low pressure developing at the base of the trough
over southern CO. Energy on the northern periphery of the trough
over central MT and WY is clipping northeast WY right now. Webcams
and observations show a bit of light snow over Campbell County
right now, and possibly over a few areas of the northern Black
Hills and Wyoming Black Hills as well. The drier trends of the
last few model runs appear to be coming true across the area,
with any accumulations across these areas tonight expected to be
on the light side, with mostly minor impacts.
Only minor adjustments made to the forecast for the rest of
tonight. Raised pops some for the rest of the evening across much
of northeast WY and the northern Black Hills, but lowered QPF and
snowfall amounts slightly for some areas. Most locations there
will see less than an inch of snowfall, with amounts up to 2
inches possible over favored areas of the northern Black Hills
where a brief period of favorable upslope enhancement is expected
late this evening. Pcpn should start to taper off fairly quickly
after midnight as drier air starts to advect into the region.
Gusty winds will persist into the overnight as well, especially
over the western SD plains, before decreasing some late tonight.
&&
.DISCUSSION...(This Evening Through Wednesday)
Issued at 140 PM MST Wed Nov 23 2022
The upper level trough is centered over the Rockies, pushing
clouds into northeastern WY and the western Dakotas. South central
SD remains sunny for now. At the surface, the cold front is
moving through the CWA, producing breezy northwest winds behind.
The strongest winds are just east of the Black Hills, where
sustained winds are 20 to 30 mph and gusts are up to 40 mph.
Temperatures range from the 30s across northeastern WY and the
Black Hills to the low 60s across south central SD.
Precipitation (mainly snow) is still expected to spread into
northeastern WY and the Black Hills this afternoon and evening, but
to a lesser extent. Thermal profiles still suggest only a brief
period of saturation for those areas, and even less across western
SD. The Froude number is only at or slightly below 1, which
decreases confidence in much upslope snow. This is supported by the
latest NBM 4.1, showing only a 20-40% chance of an inch of snow in
the northern Black Hills. Therefore, have lowered PoPs and QPF/snow
amounts further, now expecting 2 inches or less in the northern
Hills, and less than an inch in northeastern WY.
As for winds, it looks like the gustiest winds are occurring this
afternoon just east of the Black Hills. The HRRR is showing a period
of 40+ kt gusts this evening (which isn`t out of the question,
looking at forecast soundings), but most other models keep winds
lower. The ECMWF and GFS ensembles aren`t too impressive with wind
gusts either, showing this evening`s gusts less than this
afternoon`s, so opting to not issue a Wind Advisory.
The upper low will split off from the main trough tonight and slide
south, while upper ridging begins to move over the northern CONUS
Thursday into Friday. CAA will keep Thanksgiving somewhat cool (30s
and 40s), but much warmer air will advect into the region Friday,
allowing for highs in the mid 50s to low 60s, which is near the
NBM`s 90th percentile.
A weak trough will flatten the ridge Friday night into Saturday.
Cooler temperatures, breezy northwesterly winds, and possibly some
light snow showers will follow its cold front on Saturday. Looks
likely mainly northeastern WY and the Black Hills would be affected
by any light snow, with minimal accumulations expected. Highs this
weekend will be in the 30s and 40s.
Looking into next week, models are showing a trough swinging from
the Pacific Northwest through the Rockies by midweek, suggesting a
potentially colder and snowier period.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Thursday Evening)
Issued At 455 PM MST Wed Nov 23 2022
An upper level disturbance and cold front will continue to pass
through the region tonight. The main chances for light snow will
be across northeast WY and the northern Black Hills area. MVFR/IFR
conditions will become fairly widespread across northeast WY to
portions of southwest SD during the evening, lingering into the
overnight. Gusty northwesterly winds will persist, especially
across the western SD plains. Gusts of 30 to 35 kts are expected
at times, especially in the KRAP area and across portions of
northeast WY. Winds and areas of light snow will taper off quickly
late tonight, with VFR conditions and breezy northwesterly winds
on Thanksgiving day.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
Update...26
DISCUSSION...Pojorlie
AVIATION...26