Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/21/22
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 357 PM CDT Thu Oct 20 2022
.Key Messages:
-A dynamic storm system is expected to reach the area Sunday
-Strong winds, record high temperatures, severe storms, and
potentially dangerous fire weather are on the table
-Very strong winds will likely linger into the work week
.Today through Saturday:
Afternoon water vapor imagery showcases a departing trough centered
over the eastern third of the CONUS with high-amplitude ridging
taking hold of the western two thirds. This will set the tone
through Saturday, with increasing temperatures, docile winds, and
dry conditions being the expectation. As temperatures rise, moisture
isn`t exactly going to be pouring in the area so we`ll be
forecasting very dry afternoons. Highs will climb to the upper
70s to near 80 Friday, and just above 80 degrees Saturday while
relative humidity values during the afternoon hours fall to 15-25%
both days. Fire danger is expected to be high to very high, but
not extreme due to the wind speeds being relatively weak. With
that said, Saturday`s are slightly higher and could gust to 25 mph
with 15 mph sustained winds.
.Sunday through Monday:
The main concern of the forecast period begins taking shape Saturday
evening as a deepening trough develops over the Intermountain
West that quickly deepens overnight into a dynamic trough as it
enters the central CONUS midday Sunday. Before we get to too many
details, there still is significant spread on the location of the
main surface low Sunday, that could shift the areas that see each
of the following concerns east or west. As the trough deepens,
strong wind fields at all levels ramp up moisture return from the
south and brings several hazards to the table. By the time the
eventual cold front/dryline features reach the area, dewpoints
will have climbed 50s to just over 60 in eastern portions of the
forecast area resulting in meager instability to go with the very
strong shear. Severe storms will be possible, primarily during the
early evening hours. Damaging winds are the primary concern,
though hail and a tornado or two could be possible for a narrow
corridor of eastern Nebraska and southwest Iowa.
Farther west in areas where the fronts and overall system arrive
early, extremely dry and windy conditions will develop and increase
fire danger to the very high and extreme ranges; especially closer
to central Nebraska.
Very strong winds also join into the fray area-wide Sunday through
Monday where wind gusts at 45 to 55 mph appear to be nearly a lock
to occur. Some spots could see those numbers incensed by 5 to 10
mph where the strongest winds end up (mainly under the main low-
level jet streak). With those winds, the already dry conditions
will result in areas of dust and lowered visibility along with
damage to trees that haven`t quite lost their leaves yet.
On a note of lesser importance, the strong southerly flow will
also result in high temperatures that are forecast to break
records Sunday afternoon:
Forecast Record
Omaha -- 85 84 (from 1899)
Lincoln -- 87 84 (from 1915)
.Tuesday and Wednesday:
By the time we get to the middle of the work week, significant
spread is observed both between models and between members of the
same ensemble. What will be better bets weather-wise is less
wind, dry weather, increasing potential for another storm system
late week into the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 614 PM CDT Thu Oct 20 2022
VFR conditions are expected through the TAF cycle. Broken high
clouds continue to pass overhead and should continue to do so
through the overnight hours. HRRR smoke modeling shows mostly
high-level smoke from fires across the Pacific northwest spreading
across our sites by daybreak Friday and continuing through Friday
afternoon. Otherwise, low-level shear looks likely, especially at
KOMA and KLNK as winds out of the southwest develop at FL003 from
08-12z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Petersen
AVIATION...Kern
Area Forecast Discussion
National Weather Service Norman OK
1041 PM CDT Thu Oct 20 2022
...New AVIATION...
.SHORT TERM...
(This evening through Friday)
Issued at 249 PM CDT Thu Oct 20 2022
Dominant story in the short-term will be fire weather concerns
Friday. For further information, see the fire weather section below.
Winds will swing around from northerly to southerly overnight as a
weak surface low travels southeastward across the Red River and
decays. In its place, a lee trough will deepen overnight to our
north and west. Return flow will be largely dry, and mixing will
most likely counteract some modest moisture advection. With the
strength of downsloping southwesterlies and clear skies in place,
expect tomorrow to be very warm, with temperatures ranging from 85
in the southeast part of our CWA to near 90 elsewhere. Winds will be
gusty from the southwest, with peak gusts of 25-30 mph expected west
of I-35.
Meister
&&
.LONG TERM...
(Friday night through next Wednesday)
Issued at 249 PM CDT Thu Oct 20 2022
Fire weather will continue to be a prominent weather story in the
long-term. For further information on fire weather both Saturday and
Sunday, see the fire section below.
By Saturday, upper-level flow will veer to westerly as the STJ
phases with the primary mid-latitude jet to our west. This pattern
will encourage intense pressure falls to our north, with a surface
trough deepening across the High Plains from north of Casper all the
way to Midland. Strong southerly flow will encourage trajectories
off of the Gulf with return flow over the eastern half of our CWA. A
dryline should sharpen on Saturday, with the stronger winds actually
found in the moist sector where the pressure gradient will be
tighter between the lee low and a surface high over the East Coast.
Gusts could reach 30 mph or greater along and east of I-35. High
temperatures will again be well above average, especially west of
the dryline where highs may breach 90 degrees in multiple spots.
On Sunday, the surface trough will consolidate into a cyclone over
the Central Plains as the mid-latitude jet prepares to eject. The
expectation is that the low will deepen to sub-990 mb as it travels
across Nebraska Sunday afternoon, which will generate strong
gradient southerlies across our CWA. Most models show some cloud
cover remaining in place over the moist sector, and dewpoints may
approach 60 degrees on the moist side. However, the advection of a
strong EML cap will prevent convection initiation within an
otherwise modestly unstable environment. Winds will be very strong
during the afternoon Sunday, with widespread gusts over 40 mph and
possibly as high as 50 mph possible north of I-40.
The overall timing of this system continues to slow down. Thus, the
frontal passage that originally looked like it may occur Sunday
night across our CWA now looks like it may be delayed until Monday.
Kept PoPS in the forecast from Sunday night into Monday, but with
the ongoing trend it`s possible that postfrontal precipitation
doesn`t develop in our area until Monday afternoon. Once the cold
front passes, the global models diverge to a comical degree
regarding the potential for rain Monday into Tuesday. The GFS phases
the upper-level trough with a cutoff low over the east Pacific while
simultaneously merging those features with a tropical system
traveling northward out of Mexico. The Canadian agrees in principle
with that solution. Both of those models develop widespread soaking
rainfall. The ECMWF, on the other hand, lifts the trough northward
before it can impact our area, leaving us high and dry. To
complicate matters further, neither operational model agrees with
its own ensembles. We`ll continue to wait for more clarity regarding
precipitation chances and a possible cooldown early next week.
Meister
&&
.AVIATION...
(06Z TAFS)
Issued at 1039 PM CDT Thu Oct 20 2022
Southerly winds will increase toward and after 15Z, with gusts 20
KT to 30 KT during the afternoon, strongest across western
Oklahoma. No restrictions expected.
&&
.FIRE WEATHER...
Issued at 249 PM CDT Thu Oct 20 2022
Fire weather will be problematic each of the next three days. Sunday
continues to look like the most volatile day of the three, while
tomorrow looks like the largest areal extent to deal with fire
weather.
Tomorrow, dry return flow south of the developing surface trough
will encourage downsloping and deep, well-mixed boundary layers.
Winds within a southwest-northeast axis from southwest Oklahoma to
north-central Oklahoma should be around 20 mph sustained with gusts
near 30 mph. Relative humidity will drop to about 10 percent in
northwest Oklahoma and 25 percent in southeast Oklahoma. Given the
extremely dry fuels and problematic fire spread in recent weeks in
marginal fire environments, issued a red flag warning for tomorrow
anywhere that relative humidity will drop below 20 percent. Issued a
fire weather watch for south central and southeast Oklahoma, where
humidity will need to be watched. The RAP is more aggressive in
mixing out some slight moisture advection than the NAM. Dry return
flow events have a tendency to overperform in this region, and it
will be watched closely for potential red flag warning issuance in
the next forecast.
The location of elevated fire weather will become more spatially
limited on Saturday, as moisture return will likely set the dryline
up in western Oklahoma. Fire weather will still be elevated during
the day on Saturday in western Oklahoma and far western north Texas,
where relative humidity will drop to 15 percent or so. However, we
do not anticipate red flag warning criteria to be met, as the driest
air and strongest winds do not overlap.
Sunday could potentially be a very volatile fire weather day, as the
synoptic-scale jet streak ejects across the central Plains. A low-
level thermal ridge will develop northwest of the dryline. Its
intersection with the jet streak will be closely watched for
potential critical fire weather. This is still an uncertain forecast
given the possibility that the dryline may set up far enough west to
keep us entirely within the moist sector. However, if portions of
northwest Oklahoma end up behind the dryline, relative humidity as
low as 15-20 percent can be expected with winds gusting as high as
45 mph.
Meister
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 49 86 60 86 / 0 0 0 0
Hobart OK 48 87 56 89 / 0 0 0 0
Wichita Falls TX 49 90 62 93 / 0 0 0 0
Gage OK 46 89 47 88 / 0 0 0 0
Ponca City OK 45 89 58 86 / 0 0 0 0
Durant OK 47 87 60 84 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Red Flag Warning from 1 PM to 8 PM CDT Friday for OKZ004>027-
033>039-044-045.
Fire Weather Watch from Friday afternoon through Friday evening
for OKZ028>032-040>043-046>048-050>052.
TX...Red Flag Warning from 1 PM to 8 PM CDT Friday for TXZ083>090.
&&
$$
SHORT TERM...04
LONG TERM....04
AVIATION...11
Area Forecast Discussion...CORRECTED
National Weather Service Pueblo CO
357 PM MDT Thu Oct 20 2022
.SHORT TERM...(This evening through Friday)
Issued at 345 PM MDT Thu Oct 20 2022
Key Messages:
1) Red Flag Warning is in effect from 11am - 7pm for the lower
elevations of Pueblo, Huerfano, and western Las Animas Counties,
primarily for the gap flow prone areas.
2) Well above average high temperatures are expected Friday
afternoon.
Currently and the Rest of Tonight..
Very dry air has been observed across the lower elevations. The
lowest dew point observed today, so far, was -5F at KAFF at around
1PM this afternoon. Winds have been light, so no critical fire or
near critical fire weather conditions have been observed. Looking at
satellite and out our window... it is hard to even find a cloud in
the sky, outside of thin cirrus over the mountains. This air mass is
DRY. West to southwesterly winds are expected over the southern
plains throughout the overnight, so I bumped up winds as compared to
guidance around the region, but the lower Arkansas River Valley and
north may have temperatures near freezing, but not close enough to
issue any frost related highlights.
Tomorrow:
I believe the low dew points being observed today only indicate the
type of air mass that we will experience tomorrow, therefore I
decreased dew points across the area using a model blend of the
previous forecast and the HRRR 18z run. I used the 90th percentile
for winds and wind gusts to increase gap flow wind values, since the
coarser resolution models don`t handle the magnitude quite as well.
Overall, that means that there will be critical fire weather
conditions over the southern I-25 corridor from Pueblo to the New
Mexico border. I would have added Fremont County, but the fuels were
deemed not critical by the BLM in that area, but I do have to say
that the meteorological conditions for critical fire weather will be
there. Northern El Paso County is an area of uncertainty for
critical fire weather conditions, but most guidance outside of the
90th percentile NBM says that the winds will be too weak. The split
flow from Pikes Peak may not be resolved well enough, so perhaps the
RFW will need to be extended there, however it has not been included
in the RFW at this point in time. Outside of critical fire weather
and gusty winds, tomorrow will be dry.
.LONG TERM...(Friday night through Thursday)
Issued at 345 PM MDT Thu Oct 20 2022
Key Messages:
1) Warm and breezy with critical fire weather conditions possible
across the plains on Saturday.
2) Widespread snow developing Saturday night and Sunday across the
higher terrain along the Continental Divide, with windy conditions
expected across all of south central and southeast Colorado.
3) Cooler temperatures through the middle of week, with chances of
precipitation continuing Sunday night and Monday.
Friday night-Saturday...Latest models remain in good agreement of
increasing west to southwest flow aloft across the region through the
day Saturday, as a strong eastern Pacific storm system remains progged
to dig across the Pacific Northwest Coast and into the Great Basin
trough the day Saturday. With the increasing west to southwest flow
aloft through the day on Saturday, combined with steep lapse rates and
expected deep mixing, models continue to indicate critical fire weather
conditions across most of southeast Colorado Saturday afternoon and
into the early evening, and with that said have issued a Fire Weather
Watch for all of the I-25 Corridor and southeast Plains. Slowly
increasing moisture within the increasing southwest flow on Saturday
will also bring increasing chances of showers to the ContDvd late
Saturday afternoon. The increasing westerly flow will keep temperatures
at and above seasonal levels, with highs in the 70s and 80s expected
across the eastern plains, and mainly in the 50s and 60s across the
higher terrain, save for 30s and 40s at the peaks.
Saturday night-Sunday...Models continue to be in good agreement with
the movement of Great Basin system across northwestern Colorado and
into the Northern Rockies with a strong jet core translating across
south central and southeast Colorado through the day Sunday. This will
bring windy to very windy conditions to the region, with the potential
for high wind warning criteria being met across portions of the
southeastern Mts and southern I-25 Corridor late Saturday night and
early Sunday morning, with h7 flow progged to increase to 50 to 60 kts.
Strong westerly winds looks to spread east across the southeast plains
through the day Sunday and will need to access later models data for
the inclusion of a high wind watch for this timeframe. In addition, the
strong west to southwest upslope flow and increasing moisture
associated with the passing system, will bring widespread precipitation
to the higher terrain, especially along and west of the ContDvd, where
the first significant snowfall of the season. While total snowfall
amounts continue to vary between advisory and warning criteria, the
snow combined with the strong winds will create hazardous travel
conditions across the higher mountain passes of the ContDvd late
Saturday night and through the day on Sunday, with the first winter
weather highlights of the season becoming more likely. With the strong
winds, there will be continue to be high fire danger across the plains,
however, latest guidance suggest slightly cooler temperatures and
increasing moisture associated with the passing trough could keep rhs
in the 15 to 25 percent and too high for critical fire weather
conditions. With the passing trough, will see scattered scattered
showers spreading across the high mtn valleys through the eastern mts
Saturday night and Sunday, with some light snow accumulations possible
as snow level drop to between 7-8K ft on Sunday.
Sunday night-Tuesday...Models continue to differ on location of
secondary energy digging across the region in the Sunday night and
Monday timeframe, with guidance now shifting further south with said
energy. While the Canadian model remains the most aggressive with
precipitation across southeast Colorado with a closed low moving
across northern New Mexico, the latest EC now develops a closed
low across the Four Corners Sunday night which dives into southern
New Mexico through Monday, with the latest GFS in between the
other solutions. With such model diversity, have stayed with the
NBM which keeps the best pops across the ContDvd Sunday night and
early Monday, with chance pops spreading across the eastern mts
and plains. As for temperatures, highs in the 60s and 70s early
Sunday across the plains, cool into the 50s on Monday, with the
potential for a widespread hard freeze across the plains Monday
night and Tuesday night.
Wednesday-Thursday...Cool northwest flow remains progged across the
region through the middle of the work week, with another system
possible digging across the Intermountain West later next week. Current
NBM keeps temperatures below seasonal norms through the middle of next
week, with slight chances of precipitation across the higher terrain,
mainly along the ContDvd.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 345 PM MDT Thu Oct 20 2022
VFR conditions are expected at all three TAF sites, KCOS, KPUB, and
KALS, for the next 24 hours. Sky conditions are expected to be
clear, with no precipitation, and light diurnally driven winds
throughout the majority of the forecast period. By tomorrow
afternoon gusty winds are expected over KALS and KPUB, whereas KCOS
may be stuck in an eddy producing southeasterly return flow. If that
occurs LLWS may be an issue tomorrow afternoon.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday morning through Saturday
evening for COZ226>237.
Red Flag Warning from 11 AM to 7 PM MDT Friday for COZ228>230.
&&
$$
SHORT TERM...SKELLY
LONG TERM...MW
AVIATION...SKELLY