Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/22/24
Area Forecast Discussion...Updated
National Weather Service Billings MT
819 PM MDT Thu Mar 21 2024
.UPDATE...
Updated forecast precipitation chances and amounts along with a
slight cooling of temperatures and adjustments to precipitation
type and snow amounts for tonight into tomorrow.
Reason for the adjustments is the recent models poor handling of
the cold air position in the surface to 700mb layer and thus the
handling of the over-running precipitation. Recent models think
the low level frontogenesis is near a Miles City to Ekalaka line,
but its actually from south of Harlowton to Laurel to Alzada based
on surface analysis and radar returns showing where the over-
running precipitation bands are.
This was a problem earlier today as well with the snow around
Billings being depicted well to the northeast in
Musselshell/Rosebud county. The last several HRRR runs are
getting a better handle on things but the NBM is still showing the
precipitation in the wrong location (too far north). So, adjusted
precipitation further south.
Models all drag colder air south across the whole CWA, so this
will happen faster than previous forecast anticipated, and
precipitation type will switch to snow sooner over central and
western zones. Expect a broad band of snow to set up from
Harlowton to Billings to southern Rosebud county late tonight into
tomorrow morning along the 850-700 frontogenesis band. Snow
accumulations will generally be in the 1 inch range by mid to late
morning, but locally 2 or maybe even three inches is possible
where this banding sets up and persists, especially over higher
hilltops. Precipitation accumulations look to be 0.05 to 0.15
through tomorrow morning. Lows tonight will be mainly in the low
to mid 20s, with a bit warmer conditions in the western foothills
closer to 30 degrees.
Expect locally slick road conditions for the Friday morning
commute, along with patchy fog further reducing visibility along
with the light snow. Chambers
&&
.DISCUSSION...
Rest of Today through Friday Night...
The baroclinic zone is beginning its fluctuations across the area.
We had the backdoor cold front pass through this morning and keep
us on the cool side of things. That said,a thermal trough is
providing one last push of snow across the area, briefly reducing
visibilities down to half a mile under it. Behind it is finally
the brief warm-up of today via some surface downsloping and the
sun trying to peak through the clouds. This will help surfaces
melt any lingering snow or ice lingering on them. That said,
instability is increasing over the mountains for this afternoon,
and will result in a small chance for light storm activity and
even thundersnow to occur. Latest hi-res model guidance has
continued to have high confidence in putting snow and rain over
the mountains and adjacent foothills, especially the Beartooths.
That said, this weakly forced system has not been depicted well by
the models over the past 24 hours, so that does lead to a
decrease in confidence in this splattering of rain/snow to occur
through this afternoon.
Another front pushes the baroclinic zone back into the mountains
tonight and more upslope flow and cooler temperatures return for
all of southern MT. An overrunning of mid-level moisture will
occur throughout Friday to bring a 30-60% chance of snow across
the area, but any accumulations will generally stay under an inch.
Temperatures look to hover more on the cool side finally for
Friday and not retreat to the north this time, keeping Friday`s
highs only climbing into the mid to upper 30s. The end of the week
is the start of the change back to cold and snowy conditions. The
false spring is over.
Vertz
Saturday through Wednesday...
.Key Messages...
... Significant winter storm hitting the area Saturday night into
Sunday.
... Cold temperatures come in behind the snow storm with subzero
lows possible.
Shortwave ridging will begin to flatten out on Saturday, as a
dynamic low pressure system approaches from the west. This system
will bring colder temperatures and ample moisture into Monday.
Temperatures will be in the upper 30s to upper 40s on Saturday,
before dropping into the upper teens and mid 20s, Sunday and
Monday.
Models are showing a low pressure center setting up in NE Wyoming
Saturday night, with a strong flow at 850mb coming up from the
Gulf of Mexico. These winds will wrap around the low pressure,
becoming north-east oriented, and provide a potentially favorable
period of upslope for the mountains. The extent of these low-
level winds is notable, with models depicting near-blizzard
criteria winds out east, near Baker, for a several hour period
Sunday. With high snow amounts and 30-40 mph winds, traveling
conditions will deteriorate greatly. Initial snow ratios will be
in the low teens, before enough cold air infiltrates the region,
raising them into the upper teens to around 20 to 1. With this
occurring, accumulations will further increase, especially out
east for Fallon County where current forecasts have around 10
inches of snowfall. As for other counties in the north and east,
4-7 inches are currently forecasted, and 1-4 inches elsewhere. As
for the mountains, 6-12 inches are possible. With the higher
amounts, winter highlights may be needed. Precipitation chances
will decrease into Monday, leaving scattered chances across the
area.
Another important aspect of this system will be just how cold
temperatures are going to get. Sunday high temperatures in the
20s, which would be 25-30F below normals, and Monday high temps in
the upper teens and 20s, 30-35F below normal. Overnight lows in
the low 10s and single digits Sunday and Monday night. Areas that
see higher snow accumulations, specifically out east, have
overnight lows in the single digits forecast.
An unsettled pattern continues into the middle of the week,
although temperatures will rise back into the 30s and 40s. Periods
of precipitation are possible once more as a disturbance wafts
through the region Tuesday. Another potential system is shown by
models late Wednesday, however it is too soon too determine what
to make of this right now.
For relevant snow probabilities, go to weather.gov/billings.
Matos
&&
.AVIATION...
A band of snow showers will set up NW of KBIL down through KSHR
around 6Z tonight and slowly move east through the morning.
MVFR/IFR conditions will be possible for these locations and east.
Snow showers will begin to develop over the mountains and
foothills late into the afternoon. Mountain obscurations are
possible. TS
&&
.PRELIMINARY POINT TEMP/POPS...
Fri Sat Sun Mon Tue Wed Thu
-----------------------------------------------------------
BIL 025/038 026/039 021/025 011/025 010/038 020/047 028/042
67/S 46/O +9/S 43/S 12/S 22/R 35/S
LVM 030/046 028/043 023/028 014/032 018/044 026/048 030/042
22/O 38/O 97/S 32/S 23/S 23/O 56/S
HDN 024/039 024/045 020/027 009/028 006/039 016/050 025/043
78/S 44/O +9/S 53/S 11/B 21/B 35/S
MLS 022/031 023/037 019/021 007/017 000/027 008/037 019/036
54/S 64/S 9+/S 51/E 00/B 00/B 13/S
4BQ 022/036 024/046 021/025 009/022 003/035 014/048 023/045
33/S 31/B 89/S 51/E 00/B 00/B 13/O
BHK 018/031 016/031 014/023 004/017 905/025 005/036 016/037
62/S 65/S 9+/S 61/E 00/B 00/B 12/S
SHR 028/044 024/050 021/028 009/027 010/042 021/053 026/046
43/O 12/R 99/S 42/S 11/B 11/B 25/O
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Watch in effect from Saturday evening through
Sunday evening FOR ZONES 31>33-37.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Cleveland OH
1026 PM EDT Thu Mar 21 2024
.SYNOPSIS...
High pressure moves off to the east tonight and tomorrow. A
warm front moves north into the forecast area on Friday with a
low and associated cold front moving east across the area Friday
evening. Behind the cold front, high pressure moves east across
the Great Lakes region on Sunday before departing to the east
on Monday.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
The 00Z DTX sounding showed a very dry layer of air above 800mb
with dewpoint depressions of 50-60F. Surface dewpoints are also
low in the teens. With that drier air noted and the HRRR
trending north with the precipitation band, removed low pops
from the pre-dawn and morning hours across the north from Toledo
to Cleveland. A low pop remains for Erie, PA as forcing in the
850-700mb layer slides east across Lake Erie towards midday.
Previous discussion... High pressure centered over the area
this evening departs to New England and the east coast tonight.
An upper-level trough and associated surface low approach from
the west tomorrow. A warm front extending eastward from the low
approaches from the south, with frontogenesis at 850mb
responsible for a low chance of light snow across some of our
northern counties Friday morning, and possibly early Friday
afternoon in Northwest Pennsylvania. There is some spread in
model guidance with precipitation. For example, the HRRR is the
most aggressive with this precipitation, with light snow bands
even into the early afternoon, while the NAM has no snow
actually reaching the ground (the NAM has weaker frontogenesis
and is drier in the low-levels). Will maintain at least low PoPs
(20-30%) for most of our northern counties.
As the aforementioned low approaches from the west, the surface
warm front lifts north, placing a good portion of the forecast
area within the warm sector. Dawn temperatures in the upper 20s
should rise to the 40s areawide, and even low 50s for parts of
central Ohio by mid afternoon into the early evening hours. Rain
showers develop areawide by 00Z/Sat, with showers gradually
ending from the west as the low and an associated cold front
makes eastward progress across the area. Temperatures drop into
the 30s late Friday night, with some snow possibly mixing in by
very late Friday night into early Saturday morning.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Surface low will be on its way out of the local area by the start of
the short term forecast period. Can`t rule out a few lingering snow
showers across portions of Northeast Ohio and Northwest
Pennsylvania before drier air and high pressure enters from the
west. The high will continue to build in from the north and provide
dry weather and a mainly clear sky though the rest of the short term
forecast period. Cooler on Saturday with highs in the upper 30s to
lower 40 on Saturday. Warmer on Sunday as high temperatures rise
into the mid to upper 40s. Overnight lows will follow a similar
warming trend with lows Saturday night settling in the low 20s and
Sunday night lows in the lower 30s.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
Aforementioned high pressure will exit through the day Monday as low
pressure centered over the Great Plains will lift a warm front
northeast across the region. As the surface low approaches the local
area late Monday into Tuesday, have PoPs gradually increasing with
highest PoPs expected Tuesday morning and afternoon as the low and
cold front move eastward. Some uncertainty on how slow the front
moves and how much moisture lingers behind the system. Have slight
chance to chance PoPs lingering along and east of I-71 through
Wednesday. High pressure returns for Thursday and will allow for any
remaining showers to exit the region.
Warm on Monday with highs in the lower 60s and overnight lows in the
mid 40s Monday night. Gradually cooling down through the rest of the
week with highs in the upper 40s by Thursday.
&&
.AVIATION /00Z Friday THROUGH Tuesday/...
VFR conditions are expected to continue until possibly late in
the period. Skies are nearly clear except for some lingering
clouds off Lake Erie at ERI. These clouds should tend to clear
through 06Z while high clouds arrive from the west and gradually
lower into Friday. Some precipitation may develop along a warm
front aloft on Friday near Lake Erie but expecting low levels
to be too dry to include in the forecast at this time. If this
does materialize, could start out as flurries or light snow. Better
chances of rain develop late Friday afternoon into Friday
evening and did include showers in the vicinity after 22Z at
MFD/CAK/CLE. Showers should develop at CLE after 02Z and
conditions should deteriorate through the evening as a cold
front settles south of Lake Erie. Ceilings could be down to IFR
by 06Z with reduced visibilities in rain.
Light north to northeast winds will shift to the east overnight
at less than 10 knots. Winds may shift a CLE and ERI may shift
back to northeast after 16Z Friday.
Outlook...Periods of snow and/or rain with non-VFR possible
Friday night into Saturday. Non VFR possible again with rain on
Tuesday.
&&
.MARINE...
Small Craft Advisories have expired across the lake earlier this
afternoon as winds have turned west and decreased to 15 knots or
less. Winds eventually turn southeasterly by Friday morning and
increase to 15-20 knots as high pressure builds east and low
pressure approaches from the west. Winds increase to 15-20 knots
ahead of the low pressure system Friday afternoon while turning and
becoming northeast and eventually northerly behind the system by
Saturday. Northerly and onshore flow will allow for wave heights to
build to 4+ feet Saturday afternoon. We may need another round of
small crafts for the central basin of the lake this weekend to
account for that. High pressure will turn winds easterly at 10-15
knots for the end of the weekend and beginning of next week.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Saunders
NEAR TERM...KEC/Saunders
SHORT TERM...Iverson
LONG TERM...Iverson
AVIATION...KEC
MARINE...Iverson
Area Forecast Discussion
National Weather Service Dodge City KS
551 PM CDT Thu Mar 21 2024
.KEY MESSAGES...
- High confidence for strong winds from Saturday through Monday.
- Severe weather potential Sunday afternoon and evening for
areas along and east of highway 283.
- Increasing confidence in some accumulating wet snow on grassy
surfaces Monday for areas along and northwest of a Hays to
Liberal line.
&&
.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 203 PM CDT Thu Mar 21 2024
18Z observations show skies have become mostly sunny across
western Kansas as a stratus deck has completely eroded in our
western zones. In the upper levels a shortwave trough is slowly
moving east in the Texas panhandle and another shortwave is
developing in eastern Wyoming. At the surface a weak low and
trough in eastern Colorado has led to the winds switching to the
southeast and south.
For tonight the shortwave in Wyoming will move to the south and
east through the overnight and a 1007 mb surface low will
develop in Nebraska dragging a cold front to the south and west.
The cold air shouldn`t arrive in our CWA until around sunrise in
our northwest zones. Ahead of the front lower level moisture and
stratus should develop being ushered in by southeast winds for
areas southeast of Dodge City. By sunrise areas of fog should
develop along and east of an Ashland to St. John line and
visibilities could be around dense fog criteria (1/4 mile or
less).
Friday the cold front will quickly move through southwest Kansas
and should be through the entire region by 9AM. With the mixing
behind the front the fog should quickly erode and winds will
increase to 20-30 mph with higher gusts. Winds will stay strong
through the late afternoon and then diminish as a surface high
moves in from the northern plains. With north to northeast winds
through the day we should have good cold air advection and high
temperatures will be in the upper 50s to mid 60s.
Friday night the approaching storm system will start to take
shape off the Pacific coast and the strong subtropical jet will
start to become more southwest to northeast oriented. This
orientation will form a 700 mb shortwave and a surface low in
the front range and surface winds in western Kansas will start
to switch back to the southeast. Winds will start out lighter
for most of the overnight and then we should see the winds
increase especially near the Colorado border by sunrise. The
stronger winds should enough mixing to modify the cold air mass
slightly and lows will fall into the upper 20s to mid 30s.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 242 PM CDT Thu Mar 21 2024
Increasing confidence in a high impact weather system for
southwest Kansas from Saturday afternoon through Monday
afternoon. Winds, fire weather, severe weather, and snow are all
on the table.
The overall setup has long range ensembles showing a large
longwave trough moving from the Pacific coast to the central and
southern plains from Saturday through Monday. On the south side
of the trough a subtropical jet with 140-160 kt winds will help
to either turn the trough more negatively tilted or a closed low
from Sunday afternoon through Monday. With the latest Euro
ensemble run the negative tilt trend is continuing which would
lead to a slower progression of the system and the severe
weather setup moving back to the west into southwest Kansas.
Starting with the general surface winds there is near certainty
with how the forecast is shaping up of strong winds across
southwest Kansas ahead of the main system as well as behind the
system. Winds will ramp up Saturday afternoon as a surface low
deepens in eastern Colorado to around 996 mb by 00Z. NBMv4.1
winds are already at sustained 25-30 kts with gusts to 40 kts
for areas west of highway 283 to the Colorado border and
probabilities of > 30 mph is at 100% and the Euro ensembles are
in agreement with wind gusts over 34 kts being around 100%. As
the main trough enters into Colorado on Sunday the surface low
will continue to deepen and both deterministic and ensemble
models have the surface low reaching levels as low as 980 mb in
southeast Colorado by 00Z Monday. This would lead to strong
winds and potentially high wind criteria for areas along and
east of highway 283 as there is ~10% risk of winds approaching
58 mph in the Euro ensembles and 10-20% of winds greater than 50
mph in the NBMv4.1 probabilities. We should see a brief lapse
in the winds as the surface low moves through southwest Kansas
Sunday night and then winds will turn to the northwest and
increase behind a cold front for Monday where 20-30 kt sustained
winds and higher gusts will be on the table.
Fire weather will be mainly on Sunday. A dryline will setup in
the late morning through the afternoon with the latest ensemble
guidance showing the dryline reaching from Dighton to Ashland
around 4 pm. Relative humidity values will drop to 15% or less
and combining with strong southwest winds this could lead to
critical to extremely critical fire weather conditions
especially for areas from Syracuse to Liberal.
East of the dryline will be the area most favorable for severe
weather. What will be certain is the strong winds in the 0-6 km
layer and veering winds with height especially along and east of
highway 283. Latest ensemble runs are also showing a little more
moisture with dew points reaching into the upper 40s to low 50s
by afternoon. Convective initiation around 4 pm will be in the
vicinity of the dryline which will be along and east of highway
283. The moisture will probably be the biggest determinate on
how impactful the severe weather setup will be as the upper
level dynamics are a certainty.
Monday as the main storm system moves to the northeast into
Nebraska a strong cold front will race across southwest Kansas
and a mesoscale band of snow is forecast to develop behind the
low with ensembles placing 1-2 inches of wet snow roughly along
and north of a Liberal to Hays line. Ensemble probabilities of
> 1 inch of snow are highest from Syracuse to Hays where we have
50-60%. Combining this wet snow with strong winds and we could
see impacts mainly from visibility issues as the warm ground and
temperatures in the mid 30s should keep the majority of the snow
from sticking to the roadways during the day.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 551 PM CDT Thu Mar 21 2024
An area of weak surface moisture convergence along the KS/OK
state line is allowing a cluster of weak instability and
virtually no shear showers and storms to persist. Other than
that, the cu field is few to scattered in most cases and will
like the southern storms quickly dissipate toward sunset. HRRR
model shows the development of fog after about 9 UTC in this
general area as well, but the impacts of low visibility should
be far enough removed as to not impact the closest terminal,
KDDC. By 12 to 13z or so a surface cold front will drive drier
air as well as stronger northerly winds across the southernmost
terminals, (DDC/LBL).
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Tatro
LONG TERM...Tatro
AVIATION...Russell
Area Forecast Discussion
National Weather Service Quad Cities IA IL
946 PM CDT Thu Mar 21 2024
.KEY MESSAGES...
- A winter weather advisory continues for the Highway 20
corridor for 1 AM to 1 PM Friday. A new winter weather
advisory has been issued for another row of counties west of
the Mississippi in Iowa.
- A wintry mix and accumulating snow is expected late tonight
through Friday north of Highway 30. Snow amounts of 2 to 5
inches are expected along and especially north of Highway 20.
Snowfall rates of 1 to 2 inches per hour are expected between
8 and 11 AM, creating slick spots on roads and sidewalks
during the morning commute. A mix of rain, sleet and snow
will be possible between Highway 30 and Highway 20.
- Rain is expected south of Highway 30 tonight through Friday
AM, with surface and road temperatures remaining above
freezing.
- Active weather is expected again Sunday through Tuesday
morning, with widespread precipitation and strong winds.
&&
.UPDATE...
Issued at 932 PM CDT Thu Mar 21 2024
Overall trends with the HRRR/RAP models from late afternoon and
into the evening have shown a slow drift southward with the snow
band. As a result, Jackson, Jones, Linn and Benton counties have
been added to the winter weather advisory. Additionally the
potential for heavier precipitation looks to occur during the
morning commute in this area.
Forcing indicated by the RAP is impressive. DVN and OAX 00z
soundings continue to show considerable dry air in the low
levels but have a moistening layer aloft. The ABR sounding is
fully saturated and will likely reflect conditions in the
highway 20 corridor around 12z.
The dry air at OAX and DVN indicates two things; 1) top down
saturation will occur but with the strong omegas developing it
will happen quickly and 2) the top down saturation will also
result in evaporative cooling and moistening of the atmospheric
column. An example is KMCW; at 00z the T/Td was 34/5, by 00z
with snow falling it was 30/21.
The cams have also been indicating bands of heavier
precipitation once ptype changes to all snow. Thus snowfall
amounts have the potential to vary considerably over a single
county.
Atmospheric soundings in the bands are now starting to suggest
the potential of CSI occurring. Given the extremely strong
forcing occurring, this is not surprising. Thus just before
sunrise and into the morning the potential is there for isolated
thunder to occur. Anywhere thunder occurs snowfall rates will
increase considerably and would locally enhance snowfall
amounts. The thunder could also result in a rare case of thunder
sleet if there is still some lingering dry air in the lowest
kilometer of the atmosphere.
&&
.SHORT TERM /THROUGH SATURDAY/...
Issued at 226 PM CDT Thu Mar 21 2024
Tonight, the strong clipper system is still on track to move
into the central Plains late this evening. It will quickly move
east across Iowa and northern Illinois overnight and Friday
morning. A warm advection wing of precipitation is expected to
track along the Highway 20 corridor, mainly snow, about 10 PM
to 2 AM as has been indicated by the HRRR over past several
runs. After a bit of a lull, stronger forcing along with upper
level support is expected to move across the area after 3 or 4
AM with a mix and snow dropping south into the CWA. It will
quickly change to all snow along the highway 20 corridor. The
snow rates may be 1 to 2 inches an hour briefly for an hour or
two along Highway 20 during the 7 am to 11 am time. The rain
snow mix will be between highway 30 and highway 20, with just
rain south. Snowfall accumulations of 2 to 4 inches are expected
along Highway 20 with the higher totals north. The bulk of the
precipitation will fall during the morning hours. It will
gradually end from northwest to southeast during the late
morning and through the afternoon hours. Through collaboration,
lowered SLRs a bit into the 6:1 to 9:1 range. This will be a
heavier wet snow with potential for heavy snow rates as well.
The liquid totals for this event will range from around a third
of an inch to near 0.6 inches northwest of a line from
Sigourney, IA to Mt Carroll, IL. To the SE of that line amounts
quickly taper off to a tenth to a quarter inch. Lows tonight
will be in the upper 20s to mid 30s, with highs Friday getting
into the upper 30s and low 40s north to the mid 40s to low 50s
south of I 80 and even some mid and upper 50s in the far
southeast.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 226 PM CDT Thu Mar 21 2024
Saturday...Upper MS RVR Valley high pressure to maintain a dry but
coolish day through Sat evening with sub-normal highs in the 30s to
low 40s. The first wing of elevated return flow/WAA aloft still on
track to sweep acrs the CWA with southwesterly LLJ flow Sat night
into early Sunday morning. This wing will look to produce a band of
light snow that may do a dusting up to half inch of snowfall acumms
acrs the northwest third to half of the DVN CWA.
Sunday...Increasing pressure gradient to the northeast of southwest
plains cyclogenesis to lee of the approaching upper L/W trof axis to
induce windy conditions acrs the area. Southeast fetch will lead to
a slightly warmer day than Saturday, with precip and top-down
saturation robbing from the warm up potential. More of an organized
elevated warm air advection(WAA) surge should drive some precip acrs
western and northern portions of the fcst area by Sunday afternoon,
with it possibly being wet snow or rain-snow mix with some snow
acumms possible on grassy-elevated sfc`s(Ensemble 50-60th
percentile) has 1-3 inches of wet accum acrs the northwest third or
so of the CWA by Sunday evening. Impressive warm moist conveyor
signal still there as the upper trof shears acrs the northern plains
and MO RVR Valley through Tuesday morning. But the models continue
to slow the progress of such a large synoptic scale feature, with
Sunday night now appearing to be windy, warming(not much temp drop-
off) with isolated to sctrd showers and possibly a thunderstorm
racing north acrs the area into Monday morning.
Monday and Tuesday...With current ensemble timing of the medium
range models, the pre-trof conveyor of showers with even a little
embedded thunder should be realized Monday acrs the area by midday.
Strong south to southeasterly LLVL wind fields and shear, along with
ambient temps in the 50s and 60s with sfc Dpts upper 40s to low
50s may be enough for at least a limited severe storm risk. It may
have to wait until the arrival of the in-wrapping dry slot into the
back of the system Monday afternoon or evening for a wing/line of
low-topped supercells scenario. A lot of timing and evolution
uncertainty at this juncture still with this potential. The higher
rainfall axis`s now may lay out northwest and off to the east of the
local fcst area, but warm moist conveyor feed up off the Gulf still
could produce significant rainfall close to home by Tuesday.
Tuesday still looking like a mainly dry slot windy cooling day in
the wake of the occluding cyclone complex acrs the northwestern GRT
LKS.
Wednesday and Thursday...Between system`s upper ridging will look to
bring about a bit of a mid week reprieve with moderating temps, but
another eastern Pacific upper low will look to make strides inland
and eventually approach the Midwest somewhere by late week into the
start of next weekend. ..12..
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 631 PM CDT Thu Mar 21 2024
VFR conditions through 06z/22 as a winter storm approaches from
the Plains. After 06z/22 rapid deterioration to MVFR/IFR as
rain/snow and potentially sleet develop across eastern Iowa and
eventually northern Illinois. While not included in the 00z/22
TAFs, the potential is there for bands of heavier precipitation
that may included isolated thunderstorms; the most likely time
frame is 10z-16z/22. Widespread IFR conditions are expected
after 12z/22 with a slow improvement to MVFR after 18z/22.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Weather Advisory from 1 AM to 1 PM CDT Friday for
IAZ040>042.
Winter Weather Advisory from 4 AM to 1 PM CDT Friday for
IAZ051>054.
IL...Winter Weather Advisory from 1 AM to 1 PM CDT Friday for
ILZ001-002.
MO...None.
&&
$$
UPDATE...08
SHORT TERM...14
LONG TERM...12
AVIATION...08
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
632 PM CDT Thu Mar 21 2024
...New UPDATE, AVIATION...
.UPDATE...
Issued at 630 PM CDT Thu Mar 21 2024
Isolated to scattered showers and storms have developed through the
Hill Country and back into the Edwards Plateau. Latest HRRR runs show
development into a broken line of showers and storms as it
approaches the I-35 corridor, mainly from the far north side of San
Antonio north through the Austin metro and Williamson County around
8-9 PM. The storms should continue east through the inland Coastal
Plains, near and north of I-10, and exit east of the area by around
midnight. We have seen a strong storm in Gillespie County producing
small hail. Environmental conditions remain favorable for isolated to
scattered strong storms with small hail and gusty winds, and perhaps
a severe storm or two.
&&
.SHORT TERM...
(Tonight through Friday night)
Issued at 244 PM CDT Thu Mar 21 2024
Key Messages
* Low risk for a few strong to severe storms late this afternoon
into the evening. The main severe weather threats are large hail
and locally damaging wind gusts.
Early afternoon visible satellite imagery shows clouds on the
decrease across portions of the Rio Grande plains and southern
Edwards Plateau. Farther east, low clouds remain thick across most
of the Hill Country and along and east of I-35. Current temperatures
range from near 80 along the Rio Grande to the lower 60s. Water
vapor satellite imagery also shows a compact upper disturbance over
eastern New Mexico, with another disturbance farther south across
the Big Bend region.
Cloud cover is likely to remain thick from the Hill Country and
along and east of the I-35 corridor through this evening. Farther
west, some daytime heating will be realized as as some dry air
in the low levels erodes cloud cover into the southern Edwards
Plateau and far western Hill Country. Given the upper air
disturbances noted above, we could still see a low risk (Level 1 of
5) for a few strong to severe thunderstorms for areas generally
along and north of a Rocksprings to San Antonio to Cuero line late
this afternoon and evening. The latest round of hi-res models tend
to show some isolated activity developing across portions of the
Edwards Plateau late this afternoon. Activity will likely develop
into a cluster or line of storms as lift from the upper air
disturbances begins to spread eastward this evening. This will
likely push the focus for strong to severe storms into the Hill
Country to near the I-35 corridor between 5 and 7 PM. Activity will
then shift eastward into the coastal plains region mainly during the
late evening hours. Most models agree any lingering convection will
be east of our region around Midnight. Instability will be the main
limiting factor, but a few strong to severe thunderstorms with
large hail and damaging winds are possible.
Overnight lows will be fairly mild, with 50s in store for most
areas. Mostly sunny skies and dry conditions remain in the forecast
for Saturday with highs ranging from near 90 along the Rio Grande
to the mid 70s farther east into the I-35 corridor north of Austin.
Dry air moving into the Rio Grande plains along with warm temperatures
will result in some elevated fire weather conditions due to low
afternoon humidity levels down near 15%. Dry weather continues Friday
&&
.LONG TERM...
(Saturday through Thursday)
Issued at 244 PM CDT Thu Mar 21 2024
A mild and fair stretch of weather should prevail during the vast
majority of the weekend. Upper level ridging settles over the area on
Saturday before transitioning towards a southwesterly flow aloft on
Sunday as longwave troughing establishes across the western CONUS. A
shortwave pivoting around the base of the longwave trough across the
Texas panhandle into the central plains will help to develop a
surface low off the Rockies from Sunday into Monday. This low will
help result in breezy southerly winds across South- Central Texas on
Sunday and will be the parent low for a cold front that progresses
through the region from Sunday night into Monday. This weekend ahead
of this front should see the afternoon highs top out in the 70s and
low 80s while overnight lows range from the 50s into the low 60s.
Cloud cover gradually increases this weekend as well given the
pattern.
The cold front mentioned above will bring our next chance for rain
and storms across much of South-Central Texas during late Sunday
night into Monday. Instability continues to remain limited on the
medium range guidance while the timing also does not look to occur at
the most optimal time for severe storms. With that said, the
potential for a strong storm or two could still exist. The higher
rain chances and qpf looks to focus across northern and eastern
portions of the region. Activity associated with the front shifts
eastward into/through Monday afternoon. Medium range guidance then
show a deeper extension of the trough approaching the area from
Monday night through Tuesday morning. Guidance previously did not
indicate too strong of a signal for QPF in association with this
feature, however, the deterministic GFS and several members of the
12Z GEFS show potential for some rain/storms through Monday night.
The ECMWF and CMC and their ensemble suite remain less convinced
outside from only a few ensemble members. Have elected to introduce
some 20 PoPs for now across the region and we`ll adjust over the
coming forecast cycles, if needed. If a rainy solution does occur,
temperatures will likely trend lower than the current forecast
Tuesday as well.
The troughing aloft may stick around atop the state into Wednesday
before eventually advancing eastward from Wednesday night into
Thursday. Fair and mild weather is the forecast to resume where highs
top out from the mid to upper 70s into the 80s with no rain under
mostly to partly sunny skies.
&&
.AVIATION...
(00Z TAFS)
Issued at 630 PM CDT Thu Mar 21 2024
Isolated to scattered SHRA/TSRA ongoing west of the I-35 corridor.
This activity is expected to impact near or just north of SAT around
01Z-03Z and the AUS area around 02Z-04Z. Some TSRAs could contain
small GR and gusty winds. Activity should exit east of the I-35
corridor after 04Z. Low ceilings and BR are then expected overnight
across portions of the Hill Country and along and east of the I-35
corridor, including SAT and AUS, with LIFR to IFR conditions.
Clearing is expected west to east 14Z-16Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 55 78 55 76 / 50 0 0 0
Austin Bergstrom Intl Airport 55 77 52 76 / 50 0 0 0
New Braunfels Muni Airport 55 81 53 77 / 30 0 0 0
Burnet Muni Airport 53 76 51 75 / 60 0 0 0
Del Rio Intl Airport 55 90 56 83 / 10 0 0 0
Georgetown Muni Airport 55 74 52 73 / 60 0 0 0
Hondo Muni Airport 53 85 51 78 / 20 0 0 0
San Marcos Muni Airport 55 79 52 77 / 40 0 0 0
La Grange - Fayette Regional 58 76 54 77 / 40 0 0 0
San Antonio Intl Airport 56 82 55 77 / 20 0 0 0
Stinson Muni Airport 57 84 55 78 / 10 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...76
Short-Term...Platt
Long-Term...Brady
Aviation...76
Area Forecast Discussion
National Weather Service San Angelo TX
634 PM CDT Thu Mar 21 2024
...New AVIATION...
.SHORT TERM...
(This evening through Friday)
Issued at 148 PM CDT Thu Mar 21 2024
WV imagery shows the upper trough finally moving east through
Texas this afternoon, bringing an end to the cooler, wetter
weather of the past week. But not without one last round of
convection this afternoon/evening as the trough moves through.
Mesoanalysis shows the cap is gone, and sbcapes in excess of 1000
J/kg across a large portion of the CWA. Latest HRRR develops the
first cells across the Big Country by around 20Z, developing into
a line along the eastern fringes of the CWA by late this
afternoon/early evening. However, the 12Z HREF keeps deeper 0-6km
shear (>= 40kts) just east of a Brownwood-Brady-Mason line, so a
few cells could go severe before exiting the area to the east.
We`ll note this in the HWO. This activity should be well east of
the CWA by midnight.
Otherwise, weak ridging follows the trough Friday, resulting in
highs just above normal.
&&
.LONG TERM...
(Friday night through next Thursday)
Issued at 148 PM CDT Thu Mar 21 2024
A weak cold front will settle into the area Friday afternoon, and
this will shave 2-3F off Saturday`s high, bringing them down to
right around normal. Temperatures recovery by 2-3F Saturday, but
the next trough arrives Sunday, with a Pac front sharpening up a
dryline and pushing it into the area late Sunday afternoon and
night. Another round of convection is anticipated on the dryline,
developing into a severe squall line during the evening. We`ll
mention this in the HWO as well.
A secondary trough arrives Monday/Monday night, but this will be
dry, as all the boundary layer moisture will have been scoured
east by Sunday night`s dryline. A rather strong cold front will
drop in behind this trough, taking highs by Tuesday afternoon over
10F below normal in some locations. Temperatures recover
Wednesday and Thursday, with highs Thursday afternoon perhaps the
warmest this forecast.
&&
.AVIATION...
(00Z TAFS)
Issued at 633 PM CDT Thu Mar 21 2024
Scattered TSRA and SHRA are moving out from area TAF sites. KBBD
will be affected through the next hour or so, but expect activity
to quickly diminish as daytime heating is lost. Expect all
precipitation to be out of the area by no later than 03Z. After
the precip exits the area, should have only VFR level SCT or BKN
clouds for the rest of the forecast, with the exception of KABI.
Could have some MVFR CIGs at KABI from after 09Z through the mid
morning hours before clouds scatter out there as well. VFR
conditions at all sites from late morning tomorrow through the
afternoon hours with winds turning to the north at around 10
knots, with gusts to around 20 knots at times.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 48 74 45 73 / 30 0 0 0
San Angelo 46 79 46 77 / 10 0 0 0
Junction 47 81 47 79 / 10 0 0 0
Brownwood 49 72 46 72 / 60 0 0 0
Sweetwater 47 74 46 72 / 10 0 0 0
Ozona 47 80 47 75 / 0 0 0 0
Brady 48 74 47 73 / 30 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...44
LONG TERM....44
AVIATION...20