Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/23/23
Area Forecast Discussion
National Weather Service La Crosse WI
1057 PM CDT Fri Sep 22 2023
.UPDATE...
Issued at 700 PM CDT Fri Sep 22 2023
Things continue to be on track with few surprises. Instability is
in the 500 J/Kg range over much of the area with pretty skinny
CAPE profiles. There is a better CAPE gradient south into the
Highway 20 corridor as the warm frontal zone is approached which
is a bit south of there. One good storm continues with a
persistent mesocyclone northwest of Cedar Rapids. As this moves
northeast, it should become more and more elevated and not
leverage surface parcels as it has been able to do for two
tornadoes. Thus, a diminishing tornado threat as it moves
northeast toward Grant county. Otherwise, have decreased the
thunder coverage to isolated across most of the area except the
southernmost portion into the instability gradient.
Rain rates are not too high considering the anomalous preciptable
water axis into northeast IA. GOES PW would estimate around 1.3".
The highest hourly rainfall rates we have seen are about 1/4" in
northeast IA thus far. Again, just not strong forcing or higher
instability for higher rates.
Have worked a bit to move precipitation out earlier than previous
forecast...after midnight from the south...sans the deformation
area northwest of the low from KEAU-KMCW.
&&
.DISCUSSION...(This evening through Friday)
Issued at 303 PM CDT Fri Sep 22 2023
Key Messages:
- A period of widespread rain/storms (70-90% chance) is expected
for much of the area tonight with some areas likely to receive
1-2".
- A secondary round of rain and storms will arrive Saturday afternoon
through Sunday with the greatest likelihood (60-80% chance)
for precipitation expected along and west of the Mississippi
River.
- A few strong to severe storms are possible, mainly along I-35,
Saturday afternoon and evening.
Tonight:
Early this afternoon, a plume of slightly enhanced moisture
persisted across western WI within modest moisture transport. With
broad warm advection and a weakly unstable, uncapped environment,
scattered showers have continued to develop in this area. Thin,
skinny CAPE profiles with only very weak instability above the
freezing level suggest any thunder would be isolated.
Larger scale moisture transport will increase late this
afternoon/tonight area-wide ahead of an approaching shortwave/MCV
from the southwest. This will set the stage for a period of more
widespread showers/storms late this afternoon/evening as
precipitable water values near 200% of seasonal norms. CAMS indicate
at least scattered showers/storms could persist behind the trough
through the night within the persistent warm advection. If current
trends hold, a widespread healthy rainfall would fall over much of
the area tonight the HREF probability-matched rainfall through 7 am
Saturday around 1-2", but given the nature of convection, amounts
will vary considerably across the region. In general, the HREF
indicates a 40-70% chance for at least 1" and 10 to 40% of at least
2" across a large swatch of the area. A few CAMs even indicate
localized amounts exceeding 3" in spots. Overall, parameters are
marginal for more widespread heavy rainfall, with MUCAPE mainly less
than 1000 J/kg and warm cloud depths perhaps reaching 3.5 km, but
12Z CAMs generally do indicate somewhat stronger moisture
transport/low-level jet compared with 00Z runs. The modest CAPE
should limit storm intensity, but some small hail is possible with
stronger cores.
Saturday afternoon into Sunday:
As an upper-level closed low progresses into the Dakotas Saturday
and Sunday, our region will be sandwiched between cyclonic flow from
the upper-level low and weak easterly flow associated with an upper-
level high pressure system near the Hudson Bay. This will create a
situation where significant moisture advection from middle and upper
level southeasterly flow will be present across portions of Iowa and
Minnesota but will be fighting a drier airmass firmly entrenched in
Wisconsin. Consequently, the general trend with guidance has been to
have a line of storms moving eastbound but quickly falling apart as
it approaches the Mississippi River and gets into the drier air. The
22.06z EC and GEFS ensemble QPF shows this trend well with a general
70 to 90 percent chance of over 0.5" of precip, with chances rapidly
diminishing to zero upon crossing the Mississippi River with the
loss of much of the convection that would be driving the higher
totals.
The severe threat Saturday evening will be fairly conditional with
respect to the orientation of an instability gradient associated
with the moisture axis along and west of I-35. This will generally
keep most of our CWA, aside from our extreme western counties,
outside the main instability axis with MLCAPE values of around 1500
J/kg as shown in the 22.15z RAP and 22.12z HREF. The low
instabilities likely would create some difficulty for any severe
criteria hail to form but when considering 40 to 45 knot 0-6km
shear in the 22.15z RAP, cannot completely rule some larger hail.
A few severe criteria wind gusts are also possible with decent
low- level shear shown in 22.15z RAP resulting from a roughly
50-60kt low-level jet. However, the latest RAP soundings would
suggest that capping will take place with some low-level WAA late
Saturday. This would make it very difficult for any storm to
utilize the strong low-level jet and keep convection fairly
elevated. As a result, a few strong to severe storms are possible
(10-20% chance) earlier in the evening but will quickly weaken as
they progress eastward during the overnight.
Next Week:
Slight precipitation chances remain as the upper-level low is
expected to linger through early Monday, keeping our highs on the
cool side Sunday from anywhere in the middle 60s to near 70. As the
upper-level low starts to be squeezed by a building ridge over the
rockies and an upper-level high over the Hudson Bay, the low gets
ejected from our region late Monday and into Tuesday. This will put
our region into a drier and seasonable pattern for the first half of
the week, keeping our highs in the lower and middle 70s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1058 PM CDT Fri Sep 22 2023
A mesoscale convective complex will continue to move northeast
across the area through the remainder of night. KRST will continue
to see IFR/MVFR through mid-Saturday morning and then become VFR.
KLSE will likely remain VFR through 23.09z and then become MVFR
and possibly IFR into the early morning hours of Saturday before
becoming VFR again. Currently have showers continuing to around
23.15z at both TAF sites. However, a bit concerned that these
showers might be in the forecast too long based on the latest
CAMs.
With the CAMs consistently showing a line of showers and maybe
some storms affecting KRST on late Saturday afternoon, added VCSH
beginning at 23.23z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...Baumgardt
DISCUSSION...JM/Naylor
AVIATION...Boyne
Area Forecast Discussion
National Weather Service Cheyenne WY
644 PM MDT Fri Sep 22 2023
.UPDATE...
Issued at 558 PM MDT Fri Sep 22 2023
Latest local model is showing a peak of stronger winds developing
during the next few hours as the upper level trof swings through
the area. As a result, we are planning on issuing a High Wind
Warning for the Ferris Mountain Range beginning at 03z and
continuing through 18z.
&&
.SHORT TERM...(This evening through Saturday Night)
Issued at 355 PM MDT Fri Sep 22 2023
The main concern with this portion of the forecast is the
potential for severe storms erupting again this evening and high
wind potential tonight into Saturday morning.
Latest water vapor loop was showing the negatively tilted closed
low still spinning over eastern Idaho. Still a lot of jet energy
plowing through Utah and Colorado which may tend to slow down the
progression of the closed low and also help increase the intensity
of the upper level low. With this in mind, we are a little
skeptical that this closed low will move through the area as fast
as the models are projecting. We will also most likely see another
round of convection develop towards midnight in response to the
closed low which will result in steep lapse rates and MUCAPES
close to 2000j/kg and bulk shear values of 50 to 60kts. We will
need to keep an eye on how this cluster evolves and whether it may
turn into a squall line due to the strength of winds aloft
getting translated to the surface. The main focus area for this
cluster of storms will be along and north of a Wheatland to
Alliance line.
Still looking at a very high wind event evolving over areas mainly
along and west of the I-25 corridor from midnight through noon
Saturday. The local modeling is currently indicating the strongest
winds in the wind prone regions of Bordeaux, Arlington and the
I-80 Summit and foothills. However, there is a brief window around
midnight that places the Ferris Mountains reaching that potential
as well. We did not issue a warning for that area yet, but will
continue examine things a little closer. The bulk of jet energy
moves out of the region Saturday afternoon into Saturday evening,
but this will be highly dependent on how soon the upper level low
can depart the area.
.LONG TERM...(Sunday - Thursday)
Issued at 413 AM MDT Fri Sep 22 2023
Overview: Long stretch of quiet weather with warming temperatures
and general breeziness is expected through much of next week. Winds
could stay elevated enough across the region and with the dry
conditions some fire weather concerns may develop Monday into
Tuesday. Outside of that expect a quiet weather week with the
potential for precipitation chances to return to the forecast toward
next Friday (Day 7)
Discussion: Minimal changes made to the long term forecast period
with large amplitude ridging building into the region. Slight
adjustments were made to the wind and wind gust forecast for Monday
and Tuesday in addition to slight temperature adjustments. Models
are locked in with this large ridge sitting across much of the
Interior West through much of the upcoming week. This will translate
to dry and quiet conditions under mostly sunny skies. The main
weather hazard will be the potential of some fire weather conditions
developing across portions of the region Monday and Tuesday as winds
stay gusty in the 20 to 30 mph range. The ridge will eventually move
just enough east which will aid in decreasing the wind speeds by mid
week and with the ridge overhead temperatures are progged to respond
with 80F temperatures returning to the forecast for the Nebraska
Panhandle and along the North Platte River valley with widespread
70s expected elsewhere.
The pattern holds before we begin to switch the flow back to the SW
as the ridge is pushed further east by the next developing storm
entering the Pacific Northwest. Lots of uncertainty amongst the long
range models and the ensemble members with this next storm, but
precipitation chances could return the forecast by the end of next
week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 536 PM MDT Fri Sep 22 2023
The main concern with this TAF issuance is the timing of cluster
of thunderstorms this evening and overnight and timing of the
frontal passage.
Latest satellite loop was showing lots of altocumulus castellanus
passing through southeast Wyoming. These clouds are usually a sign
of more thunderstorms to come. The latest HRRR is showing a
cluster of storms developing mainly north of Wheatland after 04z
and then shifting southeast as the night progresses. This model
also shows the cluster of storms exiting the Nebraska panhandle
after 08z.
The other factor to consider this evening and overnight is the
strong winds developing behind the front. At this point, the front
is progged to move through RWL and LAR by 06z and the remainder of
the TAF sites by 12z. Powerful winds are expected along the I-25
corridor including the I-80 summit and Arlington tonight into
Saturday morning. These winds should begin to slacken somewhat
Saturday afternoon.
&&
.FIRE WEATHER...
Issued at 355 PM MDT Fri Sep 22 2023
A couple of rogue thunderstorms will continue to move out of the
Nebraska panhandle by early this evening. Another cluster of
showers and thunderstorms will build over the area later this
evening and overnight mainly north of a Wheatland to Alliance
line. Some of these storms may also become severe tonight. A
powerful cold front will move through the area late this evening
and overnight and produce wind gusts of 50 to 70 mph with higher
gusts up to 80 mph possible in Arlington and locations along the
I-25 corridor. These wind speeds should gradually diminish during
the course of the afternoon and evening on Saturday. Much drier
conditions will move into the area on Sunday and continue through
Tuesday. Wind speeds will be much lighter through Tuesday.
Afternoon humidities will generally range from 10 to 20 percent
with slightly higher amounts in the northern Nebraska panhandle.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning from 9 PM this evening to 3 PM MDT Saturday
for WYZ106-107-110-115.
High Wind Warning from midnight tonight to 3 PM MDT Saturday for
WYZ116-117.
High Wind Warning from 2 AM to 3 PM MDT Saturday for WYZ118.
NE...None.
&&
$$
UPDATE...REC
SHORT TERM...REC
LONG TERM...AW
AVIATION...REC
FIRE WEATHER...REC
Area Forecast Discussion
National Weather Service Duluth MN
629 PM CDT Fri Sep 22 2023
.DISCUSSION...(This evening through Thursday)
Issued at 321 PM CDT Fri Sep 22 2023
Key Messages:
1) Scattered showers and storms through the rest of the day.
Beach Hazard risk will continue until this evening due to onshore
flow.
2) Saturday afternoon and night will bring the best chances
for widespread rain which would be capable of localized flash
flooding. There is a Marginal severe risk for large hail and
damaging wind gusts as well on Saturday afternoon and evening,
mainly for the Brainerd Lakes area
3) Warming trend starting next Tuesday through the rest of the
week.
Through Tonight:
Weak isentropic lift tied with a diffuse shortwave moving through
the area are leading to weak ascent across the entire region.
This will result in just enough forcing for the potential for
showers and even a few thunderstorms through the rest of the day.
Breaks in the clouds have been noted in the latest satellite
soundings with the latest RAP soundings suggesting marginal MLCAPE
in the order of 350-700 j/kg being realized later today south of
Highway 2. While no severe storms are likely due to the lack of
wind shear, we may still see some stronger pulsating storms that
would be capable of some smaller sized hail, quick downpours, and
potentially a strong gust or two. Latest model guidance would
suggest that south and west of Highway 2 has a higher chance of
seeing these stronger storms with adequate insolation. Timing of
these storms would be this afternoon stretching into this evening
before storms weaken as capping develops. Elsewhere, temperatures
will warm into the mid 70s except right along the lake where a
combination of onshore flow and a longer lasting cloud deck will
modulate the high temperature cooler a few degrees. Additionally,
due to the easterly flow off the lake, we are seeing the potential
for hazardous swimming conditions from both elevated wave heights
in the 3-5ft range and an elevated rip current risk for the
beaches surrounding the head of the lake. Lastly, with this
easterly flow, we would be looking at the risk of fog along the
Western Shore of Lake Superior which could prompt some headlines
but would be something we might consider closer to the AM
timeframe.
Tonight through Sunday:
Scattered rain showers should continue through the night as the
weak ascent is supplanted aloft of a moist airmass. We could see
some more prolonged rainfall as a potential MCV comes out of the
Wisconsin Driftless region Friday evening which would spur some
enhanced rainfall chances in our NW Wisconsin counties Friday
night into Saturday Morning. Saturday Morning should see the
highest rainfall chances move to the North Shore and extend to the
Canadian Border with an initial low level jet with rainfall rates
and amounts enhanced by the lake and terrain. Rainfall chances
will increase region wide through the evening on Saturday as an
incoming trough and associated low pressure system moves into the
Northern Plains. A warm front will move up to our southwest
counties and will be the focus of potential severe thunderstorm
development tomorrow. This will be a fairly complex system with
many moving parts, but the worst of it should stay to our south
limiting the potential severe impacts this far north as much of
the area will remain in cloud cover,and will reduce the amount of
instability that we see tomorrow. Even with favorable shear
parameters (Bulk shear >30kts), the lack of instability will
temper the severe threat this far north. This is in comparison to
further south where enough buoyancy will occur to realize a more
potent severe threat with all hazards possible. With that in mind,
the SPC has put the far SW portions of our CWA at a marginal risk
for large hail and damaging gusts. Given deep saturation the
primary threat would be damaging winds of 50 to 60 mph from
precipitation loading and momentum transfer with a strengthening
low level jet . There are still questions about the evolution of
overnight storms as well as placement of the front which means
that changes to the forecast are still possible through the next
24 hours. One of the bigger concerns will be the potential for
flash flooding due to abnormally high PWATs with slow movement
speeds of the storms expected through the weekend. The current ERO
outlook from the WPC has much of our CWA on Saturday in a slight
risk for the potential for flash flooding occurring. On Sunday,
the risk is trimmed a tad further to the south and is only a
marginal risk for excessive rainfall. The ongoing drought has led
to hydrophobic soils developing, meaning that it won’t take much
rain for ponding/flooding to occur in the areas hit the hardest by
the drought. That said, the greatest flash flood risk for
Saturday evening and night will be for urban areas and largely
driven by rates compared to amounts as forcing and moisture
quickly ramp up and then ramp down Saturday evening and night. The
greatest threat for urban flooding is for the Brainerd Lakes area
where forcing via the low level jet will be strongest. On Sunday,
the severe threat will have passed but as the low becomes
vertically stacked, however the occluded front will continue to
present rainfall chances for the entire Northland. While the
coverage seems a bit less widespread, there will be the chance for
training of storms moving over the same areas at slow speeds
potentially leading to more localized flooding concerns.
Monday onwards:
Some lingering showers may persist early Monday morning but we
should see clearing by afternoon. Temperatures will be seasonable
for late September with highs topping out in the upper 60s/lower
70s amidst southeast flow which will keep the North Shore a few
degrees cooler. A building ridge over the Northern Plains/Northern
Great Lakes through the rest of the week will usher in southerly
flow which suggests warmer than normal temperatures returning with
a chance for some 80s by mid to late week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 618 PM CDT Fri Sep 22 2023
A mix of VFR/MVFR/IFR ceiling and visibilities across the region
for the 00Z TAF issuance. An area of IFR ceiling and visibilities
is traveling inland from Lake Superior near DLH. This area is
expected to spread inland and will affect DLH and possibly HYR and
HIB. Additionally, scattered showers and isolated thunderstorms
will be ongoing through the period. As such, visibilities will
bounce between the different categories as the
showers/thunderstorms travel over the terminals from southeast to
northwest.
Winds will be easterly at 10 knots with gusts to 15 to 20 knots.
Winds will remain elevated overnight and increase tomorrow morning
to 10 to 15 knots with gusts to 20 to 25 knots.
&&
.MARINE...
Issued at 321 PM CDT Fri Sep 22 2023
Strong northeasterly winds continue to stream across Lake Superior
this afternoon and evening. Winds are expected to further increase
as we move into Saturday. The latest high res guidance still keeps
speeds below gales. With about a 30% chance of briefly seeing
gales along the North Shore Saturday afternoon. Overall, Small
Craft Advisories will be a mainstay through the weekend with wave
heights building to upwards of 4-8ft at times along the North
Shore.
Additionally, low clouds and fog continue to engulf Lake Superior.
We have issued a Dense Fog Advisory lasting through tomorrow
morning. An actively wet weekend with multiple waves of rain moving
across the Lake. Storms will be possible at times but at this time
no severe weather is anticipated for the Lake.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 66 55 62 / 70 80 90 60
INL 56 67 56 63 / 20 70 70 60
BRD 59 70 58 65 / 60 90 100 80
HYR 58 72 56 65 / 90 80 50 60
ASX 57 71 56 68 / 80 80 20 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement until 10 PM CDT this evening for WIZ001.
MN...Beach Hazards Statement until 10 PM CDT this evening for MNZ037.
LS...Dense Fog Advisory until 7 AM CDT Saturday for LSZ121-140>148-
150.
Small Craft Advisory from 10 AM Saturday to 1 AM CDT Monday for
LSZ140.
Small Craft Advisory from 1 AM Saturday to 4 AM CDT Monday for
LSZ141>143.
Small Craft Advisory until 4 AM CDT Monday for LSZ144-145.
Small Craft Advisory from 10 PM this evening to 1 AM CDT Monday
for LSZ146-147-150.
&&
$$
DISCUSSION...PA/KP
AVIATION...KSE
MARINE...Britt
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
617 PM CDT Fri Sep 22 2023
.Discussion...
Issued at 356 PM CDT FRI SEP 22 2023
Key Messages:
- Generally dry conditions with seasonal temperatures for the
remainder of today.
- Unseasonably warm and humid tomorrow afternoon, with scattered
to widespread showers and thunderstorms tomorrow mid afternoon
through tomorrow night. Severe storms will be possible, with
large hail and damaging winds being the primary hazards.
- Near seasonal temperatures with generally dry conditions
expected for next week.
Discussion:
The current synoptic pattern across the CONUS is defined by mid
level ridging over the south central US, a closed low and
troughing over the Intermountain West into the Rockies, and
another low off the coast of the Carolinas (Tropical Storm
Ophelia). Showers and storms associated with a subtle shortwave
trough moving through this morning and early afternoon have
exited to the east and dissipated. Morning storms and lingering
cloud cover has led to cooler temperatures today, with 3 PM temps
ranging from the lower to upper 70s. The remainder of the day and
into the overnight period should be dry, although some isolated
showers cannot be completely ruled out for later this afternoon as
well as overnight tonight into early Saturday morning.
The closed mid level low over the Intermountain West finally
moves into central South Dakota by tomorrow afternoon with the
accompanying trough ejecting out across the Plains and into the
western Midwest. At the surface, a cold front will extend
southward from the surface low over SE South Dakota into eastern
Nebraska and Kansas by early to mid afternoon, moving eastward.
Our region will be within the warm sector (high temps in the mid
to upper 80s, dewpoints as high as the lower 70s, and breezy
southerly winds) with a pairing of moderate instability and
sufficient deep layer shear to support well organized updrafts.
Convection allowing models differ a little bit in exact timing of
the front as well as convective initiation times and locations.
The 18z HRRR wants to develop storms out ahead of the front by mid
afternoon over NW and northern Missouri before convective
initiation along the front closer to 7 PM from NW Missouri into
far eastern KS. Meanwhile, the NAM Nest does not initiate any
storms well out ahead of the front, initiating storms over
eastern Kansas along the front by around 5 pm, with these moving
east through the KC Metro around 7 pm or so. The SPC HREF seems to
favor NE Oklahoma, SE Kansas, and far WSW Missouri for the best
chances for more significant severe weather, and as such SPC has
highlighted this region within an upgraded Enhanced Risk (this
extends into Linn County KS and Bates County MO). The rest of the
region remains within the SPC Slight Risk. Initial storms (eastern
KS, far western MO) may have the potential to produce very large
hail as storms will have the better likelihood of remaining more
discrete and will have more instability to tap into. As storms
move eastward later in the evening, they will likely grow upscale
into a line or broken line, at which point severe wind gusts will
become the primary threat. A tornado or two cannot be ruled out,
but is not the primary or even secondary threat. In addition to
the strong to severe storms, locally moderate to heavy rainfall
will also be possible, although the forecast accumulated rainfall
totals have come down significantly compared to what they were
this time yesterday.
The forward progress of the cold front looks to stall out over the
region, hanging around over the area into tomorrow night and
Sunday morning, this will keep chances for showers and storms in
the forecast through Sunday morning before coming to an end from
west to east late Sunday morning into Sunday afternoon as the
front finally completely pushes through. Highs on Sunday should
be several degrees cooler behind the front (mid 70s over NE MO to
near 80 degrees elsewhere). As we head into next week, ridging
looks to build in over the west central CONUS. There will be a few
periods of low chance PoPs, but all in all dry conditions are
favored with near seasonal temperatures with afternoon highs in
the mid to upper 70s and lows in the mid to upper 50s.
&&
.Aviation...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 617 PM CDT FRI SEP 22 2023
VFR conds will prevail to begin the TAF pd as bkn mid-lvl clouds
are expected thru 02Z before scattering out. Model differences
exist in reference to the potential for storms durg the morning
hours. Some models are dry while others develop thunderstorms in
the VC of the terminals btn 11Z-15Z as such have added VCTS for
that pd although conf is low. regardless cigs are expected to
remain VFR thru this pd with ovc cigs around 5kft. Aft 15Z bkn
mid-lvl clouds around 10kft are expected. A second round of storms
are expected towards the end of the TAF pd however, have left
mention out until the 06Z TAFs. Winds will be out of the SE btn
5-10kts thru 15Z before becmg southerly while incrg to around
15kts with gusts btn 20-25kts.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Discussion...BMW
Aviation...73
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
646 PM CDT Fri Sep 22 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Saturday night)
Issued at 107 PM CDT Fri Sep 22 2023
Midday RAP analysis depicts a 594 dm subtropical ridge centered over
northern Mexico, providing a NW flow aloft over south-central TX.
Meanwhile at the surface, a weak low is centered near the OK
panhandle, and with a broad sfc high over the eastern CONUS, flow
regionally is out of the south with some localized variations to the
SE and SW. Onshore flow will lead to a few isolated showers and
storms over the Coastal Plains today, but these will end by sunset
and probably won`t bring much rainfall even to those areas lucky
enough to receive any. The best chances will be over Lavaca County.
We`ll continue our seasonally hot conditions with highs in the 90s
to near 100 degrees, near record values for the date but unlikely to
eclipse them. Tomorrow`s record highs are lower at the I-35 sites,
and with forecast highs set to rise a degree or so relative to
today, could see a better chance to set some. Again, isolated
showers/storms are possible during the day over our far eastern
counties. There may also be a chance for a storm to sneak into
western Val Verde County tomorrow evening. Expect lows tomorrow and
Sunday morning in the 70s.
&&
.LONG TERM...
(Sunday through Friday)
Issued at 120 PM CDT Fri Sep 22 2023
A return to more active weather is expected by the back half of the
weekend as the super annoying 500mb ridge (let`s be honest, it just
will NOT go away) retreats back southwest for a few days. Northwest
flow is expected to develop as the ridge slides southwestward,
opening the door for a couple of shortwave pieces of energy to swing
through South-Central Texas. Sunday will likely be our last "hot" day
of the week, however, near to above normal temperatures look to
return by the middle to end of next week anyway.
A sfc low will form over southwestern Oklahoma on Sunday morning,
sending a cold front southward through the day and into Monday. The
front is expected to washout/hold up somewhere over our area on
Monday, resulting in what could go down as our best chance at rain in
quite some time. Ensemble guidance still isn`t very bullish on the
overall probabilities for > 1/2 of rain, putting the chances at <40%
for the entire area. However, given the continued run-to-run
consistency, there is an outside shot at a lucky few locations over
the Southern Edwards Plateau and western Hill Country of getting a
quick 1-2" Monday night. We will hold out hope for beneficial rain
but this is not expected to put much if any sort of dent in the
ongoing drought. We may continue with slight chances for rain Tuesday
and Wednesday before things dry out again. Beyond that, expect
temperatures back in the mid to upper 90s by mid to late week. Even
further out, the deterministic GFS has hinted at perhaps a big time
pattern change by next weekend, with perhaps some mornings in the 50s
and 60s. We will temper our expectations for now.
&&
.AVIATION...
(00Z TAFS)
Issued at 630 PM CDT Fri Sep 22 2023
The seabreeze will move inland this evening and bring some gusty
southeast winds to SAT and SSF through most of this evening.
Otherwise, look for clouds along and east of I-35 to decrease over
the next 1-2 hours. We do expect low clouds to develop early Saturday
morning for the I-35 sites and have continued to mention MVFR cigs
in the latest forecast between 09-16Z. Low clouds will lift back to
VFR by late morning, with gusty south to southeast winds anticipated
for all sites tomorrow afternoon and early evening.
&&
.CLIMATE...
Issued at 630 AM CDT Thu Sep 21 2023
Record High Temperatures and year last reached:
9/22 9/23 9/24
AUS - 103F (2005) 101 (2005) 101 (2005)
ATT - 102F (1926) 100 (2019) 99 (2011)
SAT - 101F (1926) 99 (2005) 102 (2005)
DRT - 102F (1946) 104 (1908) 103 (2005)
Temp (Year)
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 76 99 76 99 / 0 10 10 20
Austin Bergstrom Intl Airport 76 98 76 99 / 0 10 0 20
New Braunfels Muni Airport 77 100 77 100 / 10 10 0 20
Burnet Muni Airport 76 97 76 98 / 0 10 10 30
Del Rio Intl Airport 78 102 79 102 / 0 0 0 20
Georgetown Muni Airport 76 97 76 99 / 0 10 10 30
Hondo Muni Airport 74 99 74 99 / 10 10 0 20
San Marcos Muni Airport 76 99 75 99 / 0 10 0 20
La Grange - Fayette Regional 77 98 76 97 / 10 20 0 20
San Antonio Intl Airport 77 99 77 99 / 10 10 0 20
Stinson Muni Airport 79 101 78 100 / 10 10 0 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...Platt
Long-Term...Gale
Aviation...Platt
Area Forecast Discussion
National Weather Service Glasgow MT
849 PM MDT Fri Sep 22 2023
.DISCUSSION...
EVENING UPDATE:
Most convective storms from this afternoon have diminished,
becoming predominately stratiform rain by now. The 00Z HRRR has a
good representation of the showers moving in from the Dakotas. The
afternoon`s update of the PoP grids seemed reasonable to me, so no
adjustments were made there, aside from slightly increasing the
value slightly over the northwestern zones.
The main update made was the visibility grids as many locations
have hovered near 6SM with brief drops in visibility below that.
As such, I did a broad brush of 6SM visibility for most of the CWA
by the morning, so as to include the mention of patchy fog.
No changes to the Lake Wind Advisory as sites around Fort Peck are
occasionally gusting over 20 mph. Will let the next shift to
decide on canceling or expiring at 6 AM MDT.
-Enriquez
PREVIOUS DISCUSSION:
Tonight through Saturday Night:
Showers and a few thunderstorms have remained persistent today
from the Little Rockies into Petroleum and western Garfield
counties, but little to nothing has fallen elsewhere. Looking at
the upper-level divergence zone and axes of dilatation at the
surface, precipitation production has been funneled into this
area, despite a record high amount of precipitable water from this
morning`s sounding at Glasgow. The remaining moisture to be seen
should become more widespread, but generally be light and
scattered shower activity. Thus, forecast rain totals have
decreased, especially for Valley and Phillips counties where
amounts around tenth of an inch or less will be common. However,
there is high confidence in low clouds and patchy fog hanging
around through at least Saturday morning. Easterly winds
gradually start to subside tonight as the system moves away,
bringing an expected end to the Lake Wind Advisory.
Sunday and Beyond:
A distinct dry and warm period is becoming more clear for the
first half of the upcoming week, with some locations likely
reaching back into the 80s Monday and Tuesday. Then, the
uncertainty lies in how a developing trough over the Pacific
Northwest develops, which has the potential to bring moisture and
more seasonal temperatures by next weekend.
-Zanker
&&
.AVIATION...
UPDATED: 0245Z
FLIGHT CAT RANGE: VFR - IFR
DISCUSSION: Shower activity becoming more widespread, moving in
from the Dakotas and toward the northwest. KGDV and KSDY will have
the greatest threats with visibility dropping to IFR conditions at
times. Patchy fog will be prevalent most of the night and into the
morning.
WINDS: East winds shifting to more northeast winds at 10-15 kts
after midnight. By sunrise, locations south of the Missouri River
will be light and variable, while locations north of the Missouri
will still see 10-15 kt northeasterlies.
-Enriquez
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 6 AM MDT Saturday For Fort Peck Lake
for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service San Francisco CA
511 PM PDT Fri Sep 22 2023
...New AVIATION...
.SYNOPSIS...
Issued at 1228 PM PDT Fri Sep 22 2023
Cool pattern persists through the weekend with onshore flow.
Potent low pressure system moves into the region this weekend,
clearing out smoke and bringing rain chances next week.
&&
.SHORT TERM...
(This evening through Saturday)
Issued at 1228 PM PDT Fri Sep 22 2023
Pleasant temperatures today and Saturday with mostly clear skies.
Some lingering stratus near coastal areas. Onshore flow has
returned with a deep marine layer across the region. Overnight RH
recoveries into the 85-100% range pretty much area-wide this
morning. Expect wildfire smoke to hang around today with some
lingering into Saturday, especially where trapped in narrow
mountain valleys.
&&
.LONG TERM...
(Saturday night through next Thursday)
Issued at 1228 PM PDT Fri Sep 22 2023
By Saturday night into Sunday, winds increase and begin to push
smoke inland with the approach of a potent early-season upper low.
Ensemble guidance continues to show good agreement in the relative
track of the low through Tuesday, which brings the surface trough
into the Bay Area and not much further. Rain chances begin to
increase late Sunday night in Northern Napa and Sonoma counties,
spreading southward to the rest of the Bay Area by late Monday
morning. By Monday afternoon, the surface trough looks to be
rather diffuse across the South Bay as the surface low remains in
the Pacific NW. Locations south of the Golden Gate, and especially
south of the Bay, may only see breezy afternoon winds and cloudy
skies on Monday with little-to-no rain at all. Current storm total
amounts range from 0.25-0.5" for far northern Napa/Sonoma,
0.1-0.25" for the rest of the North Bay, and <0.1 for the rest of
the SF Bay Area. Generally lesser amounts as you go inland and
south. The probabilities for locations to see at least 0.1" are
slight to moderate...20-40% for the SF Bay Area, and 40-75% for
the North Bay, higher probabilities as you go northward.
Beyond Tuesday, guidance diverges a bit with possible solutions.
As the upper low remains off the west coast of Canada, there is a
small chance (~10% at the moment) that an embedded shortwave
trough moves through the periphery of the parent trough and brings
another quick shot of light rain to the North Bay. At this point
this is a low confidence scenario. Otherwise, expect pleasant
conditions to persist through next week with daytime temperatures
at or just below seasonal normals.
&&
.AVIATION...
(00Z TAFS)
Issued at 444 PM PDT Fri Sep 22 2023
VFR across all terminals. Winds are generally moderate from the
SW-W this afternoon. Widespread CIGs return around 08-12Z and
remain through early morning Sat. MVFR-IFR VIS impacts are
expected in the North Bay and Monterey Bay areas overnight due to
a combination of any lingering smoke and nocturnal mist. There is
some uncertainty regarding how low the visibility will drop at STS
and APC. Some model guidance is indicating a reasonable
probability for dense LIFR-VLIFR fog at STS, but the TAF only
drops to 3 mi. If this trend continues, the STS TAF will likely
drop to IFR visibilities or lower. Clearing is expected by late
morning Sat before moderate to fresh winds develop in the
afternoon.
Vicinity of SFO... VFR with moderate westerly winds of 13-15 kt
this evening. Winds will gradually diminish overnight. CIGs are a
little tricky as the HRRR model indicates a window of clear skies
will remain over the San Francisco Bay and eastern Peninsula
during the early morning hours. While this window can be hard to
pin down, it usually favors SFO over OAK, and the TAFs reflect a
later arrival of CIGs (11Z at SFO vs 08Z at OAK). The stratus
clearing has been pushed an hour to 18Z for SFO. Sat afternoon
winds will return to moderate westerlies.
SFO Bridge Approach... Similar to SFO.
Monterey Bay Terminals...Satellite imagery shows a patch of low
clouds developing on the western side of the Monterey Peninsula.
Winds at KMRY have shifted southwesterly, so may see those low
clouds funnel in between 01z and 03z, but highest confidence is
after 03z. Highest confidence of MVFR conditions overnight for KMRY
and KSNS. Some guidance hints at IFR visbys developing early
Saturday morning, but due to deep/diffuse marine layer, confidence
is low so not included in 00z TAF package. However, reductions in
visbys still possible tonight, but MVFR conditions more likely. Late
clearing expected again tomorrow between 18-20z. Smoky and hazy
conditions may linger Saturday, but should be improved compared to
today.
&&
.MARINE...
(Today through Wednesday)
Issued at 115 PM PDT Fri Sep 22 2023
Light to moderate north winds continue across the waters through
the weekend. A cold front will bring gustier winds and rain to the
northern waters starting Sunday through early Tuesday, followed
by gusty winds across the waters beginning in the middle of the
week. Northwesterly swell continues to diminish with a new
northwesterly swell system arriving on Tuesday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...Flynn
MARINE...DialH
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Area Forecast Discussion
National Weather Service Sacramento CA
111 PM PDT Fri Sep 22 2023
.Synopsis...Cool and dry weather will continue through much of
the weekend. A pattern change will bring increasing rain chances
early next week along with gusty southerly winds. Dry weather
returns by Tuesday afternoon, with mild temperatures remaining
through the end of next week.
&&
.Discussion...Today through Monday.
As of noon today, we`re still under weak northwest flow aloft,
but by early this evening we will transition to short-wave
ridging, allowing for winds to weaken and shift to more of a
southerly direction. This wind shift will help aid the hazy skies
out of our area. This is supported with the latest HRRR smoke runs
with the bulk of the smoke/haze remaining east and north of the
Sacramento and San Joaquin Valleys by tonight.
By Saturday, a more potent upper-level trough in the Gulf of Alaska
will begin to influence our weather, by bringing increased southwest
flow. This will translate to increased onshore winds, bringing gusts
around 20-25 mph to much of the region, which will continue to push
any remaining haze out of the region. The upper-level low will be
very expansive and will aid in moisture across far northwestern CA
starting as early as Saturday evening. Before the low digs and
amplifies, some vorticity waves will move through the southwesterly
flow. As such, some hires models indicate this will allow for a
light, narrow band of precip to move across portions of interior
northern CA late Saturday night/early Sunday. The moisture
associated will be fairly meager/light, resulting in little to no
impacts for much of our area.
Before the arrival of the better moisture late Sunday-early next
week, increased pressure gradients and associated upper-level jet
will also result in gusty south to southwest winds across the
region. Expect sustained winds of 12-25 mph and gusts to 25-35+ mph,
with the strongest expected across the southern Cascades and
northern Sierra Monday afternoon. NBM probabilities of wind gusts >=
30 mph is generally 50-70% Sunday afternoon across the northern
Sierra and surrounding foothills with higher and more expansive
probabilities 60-90% north and east of the I-5 and I-80 corridors
Monday. When looking at probabilities >= 40 mph, only a few areas
have 15-30% in the northern Sierra/southern Cascades Monday
afternoon.
The better moisture will arrive later Sunday, with the bulk of the
`best` moisture impacting mainly far northwestern CA. There`s still
some uncertainty in the exact details regarding timing and
precipitation totals early next week, with the latest guidance
trending slightly drier. Even so, enough moisture will spill across
Western Shasta County and Coastal Range late Sunday night-Monday,
where storm totals of ~1"-2" will be possible. Since the bulk of the
dynamics will remain north and west of our region, the rain will
primarily fall as rain showers, but any embedded vorticity waves may
cause some embedded lightning and slightly heavier showers to move
across the southern Cascades- northern Sacramento Valley.
Probabilities of 0.50" or higher are mainly confined to Red Bluff
and areas north and west, with Red Bluff having about a 30-40%
chance and Redding having 65-75% chance. Areas south of Red Bluff
will see diminishing probabilities of rainfall, with around a 15-30%
of seeing between 0.25"-0.50" down to the I-80 corridor, with little
to no precipitation forecast for the far southern Sacramento
Valley and the northern San Joaquin Valley. Overall, rain impacts
are expected to minor.
Outside of winds and precipitation, temperatures will remain 8-12
degrees below seasonal normals through the weekend, with highs in
the low 80s to upper 70s across much of the Valley. Minimum
temperatures will be cool as well, allowing for frost development
through the weekend in the mountain valleys.
//Peters
.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...
As the trough over the Pacific Northwest continues to move eastward
early next week, showers will likely continue over Northern
California on Tuesday, mostly in the Coastal Range and northern
Sacramento Valley. There is some disagreement between ensembles and
clusters as to how the system will progress late in the week, with
some showing the low dropping down over Northern California, and
others showing it moving further east before moving southward.
However, conditions should still generally be cool and dry starting
Wednesday, with temperatures in the high 70s to mid 80s in the
Valley throughout the rest of the week. The NBM is currently showing
slight chances of showers in the mountains, but probabilities are
still below 20% at the moment. //SP
&&
.AVIATION...Generally VFR conditions prevail at all TAF sites
through the forecast period. Some haze from wildfire smoke may
linger through the early afternoon across the northern San Joaquin
Valley. Otherwise, quiet weather and light winds of 10 kts or
less are anticipated at TAF sites. Breezy southwesterly winds
expected throughout the Delta.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Las Vegas NV
820 PM PDT Fri Sep 22 2023
.SYNOPSIS...A weak disturbance combined with remnant moisture from
former Tropical Storm Kenneth will move across southern California,
southern Nevada and northwest Arizona leading to chances for at
least light rain showers tonight through Saturday morning. A dry
southwest flow aloft will develop Sunday through next week with
temperatures warming back to normal.
&&
.UPDATE...Sheared off remnants of post-tropical cyclone Kenneth
continue to stream into the Mojave Desert this evening with
widespread dense mid and high cloud cover across all of Clark, San
Bernardino, and Mohave Counties this evening. Meanwhile, low levels
of the atmosphere remain exceptionally dry, with dewpoints generally
in the 20s to low 30s, or less. This has limited even so much as
sprinkles from being reported with the cloud shield so far tonight,
despite fairly widespread light stratiform precipitation echoes on
radar across our southern zones.
While moistening will continue overnight from the top down, lower
desert elevations will be hard pressed to see much more than
sprinkles by early morning, as surface dewpoints are only expected
to recover into the lower 40s at best. Better chances for measurable
rainfall will be focused across Mohave County where stronger
dynamics, orographics, and increasing elevation will help encourage
better saturation down to the ground level.
Made some tweaks to the PoPs tonight accounting for latest HRRR/HREF
guidance which trimmed the coverage of rainfall a bit for areas
outside of Mohave County. Otherwise, most things remain on track.
-Outler-
&&
.SHORT TERM...through Sunday.
Remnant moisture from post-tropical cyclone Kenneth moving over
southern California will brush southern Nevada tonight as it spreads
across northwest Arizona through Saturday morning. The 18Z HRRR has
backed off a little from the 12Z run at indicating widespread light
showers over Clark County, but there will still be at least
sprinkles possible and the 12Z HREF indicates 20-40 percent chances
of measurable rain (at least 0.01") between midnight and 6 am PDT
Saturday across much of San Bernardino, Clark and Mohave counties
which is considerably higher than the NBM. PoP values were bumped up
to reflect the HREF probabilities. The weak circulation spinning
along the northern fringe of the moisture boundary will be a bit of
a wildcard and will likely provide some dynamic support and
destabilization due to mid-level cooling which could produce
isolated thunderstorms. However, the mention of thunderstorms is
currently confined to Mohave County. These features will move across
northern Arizona Saturday afternoon followed by dry and mild
conditions under ridge Sunday with high temperatures climbing 5-6
degrees and readings in the lower to mid 90s across the desert
zones.
.LONG TERM...Monday through Friday.
Dry and fairly light zonal or southwest flow will persist over the
region Monday through Wednesday providing mild weather with near
normal temperatures. Afternoon winds should pick up Thursday and
Friday as southwest flow increases due to a broad trough digging
slightly over the western states the second half of the week.
However, model ensembles are not in good agreement with the timing
and depth of the trough which leads to low confidence in any
significant wind speed or temperature changes going into next
weekend.
&&
.AVIATION...For Harry Reid...Light east to southeast winds early
this afternoon will turn south to southwest after 21Z and increase
to around 10kts. The latest guidance is now indicating the chance of
a few showers near or in the Vegas Valley overnight, and VCSH has
been introduced into the TAFs between 08Z and 14Z. Winds should
remain southwest overnight below 10kts before going northeast to
east tomorrow morning with speeds below 10kts. CIGs will lower with
the increased moisture this evening and overnight, falling to 10-
12kft at times. Skies will improve on Saturday, with any remaining
clouds rising to 15kft or higher by the afternoon.
For the rest of southern Nevada, northwest Arizona and southeast
California...Showers and a few isolated thunderstorms are likely
this afternoon through Saturday morning, mainly along and south of
the I-15 corridor. Most TAF sites will see south-to-southwest winds
of less than 15kts develop this afternoon and evening before
diminishing overnight. The exception will be in the Owens Valley,
where a more typical diurnal wind pattern is expected, with
southerly winds continuing into this evening followed by northerly
winds overnight. CIGs will lower with the increased moisture this
afternoon through tonight, falling to 10-12kft at times. Skies will
improve on Saturday, with any remaining clouds rising to 15kft or
higher by the afternoon.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
SHORT TERM/LONG TERM...Adair
AVIATION...Planz
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