Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/06/23
Area Forecast Discussion
National Weather Service La Crosse WI
1000 PM CST Sun Nov 5 2023
.DISCUSSION...(This evening through Sunday)
Issued at 223 PM CST Sun Nov 5 2023
Key Messages:
- Medium Chances (30 to 60%) for Rain North of I94 Tonight
- Rain Chances (20 to 60%) Return Tuesday Night through
Wednesday Night...Highest Chances Further North
- Temperatures Trending in the Low to Mid 40s Thursday through
the weekend
Tonight through Monday: Gusty, Chance (30-60%) of Rain North of I94
Latest RAP analysis shows decent moisture transport across central
MN as strong isentropic ascent increases across the region. Latest
CAMs show reflectivity across our area, but surface observations
suggest precip is not reaching the surface. For tonight, model
trends continue to show the best chances for precipitation across
the north, mostly along and north of I94 tonight. Precipitation
chances range from roughly 20% along the Mississippi River to 50 to
60% along and north of WI Hwy 29. Precipitation that does fall
tonight will be on the light side, with the latest HREF
probabilities for 0.05 inches or more less than 10% south of I94.
These probabilities increase slightly to 20% along US10 in
Neilsville, 30% along WI Hwy 29, and then 50-80% along and north of
Medford tonight.
RAP analysis and regional radar VAD wind profiles paint a strong low-
level jet moving into the region this afternoon. RAP model shows
this jet will transit the area this evening through tonight, with
gusts around 25 to 30 mph expected, especially in open areas west of
the Mississippi. Despite increasing stability with warm air
advection, model soundings show strong winds just 100-200 ft AGL. It
won`t take much mixing at all to tap into these strong 30-35kt winds
just off the surface.
Mid Week: Temperatures Trending Below Normal, Midweek Rain?
Clustered ensemble guidance continues to show good agreement on the
overall pattern during the middle of the week, with varying
strengths of troughing across the western CONUS. Trends over the
last several runs have brought the best precipitation chances
further to the north, with less overall precipitation amounts as
well. Probabilities from a 100-member ensemble consisting of 50
EC, 30 GEFS, and 20 Canadian members show a slight northern trend
with the precipitation over the last few runs. Probabilities for
0.25 inches of rain in 48 hours from 6AM Tues-6AM Thurs show only
a 10-20% chance west of the Mississippi River, increasing to 30 to
40% chance along and north of I94. When accessing the potential
for 0.10 inches of rain in 48 hours, we see a 10 to 40% chance
west of the Mississippi River (decreasing further to the west),
with a 60 to 75% chance along and north of I94. While these
probabilities have fallen roughly 10% across the board from last
night`s model run, the overall potential for precipitation along
and north of I94 remains around 40 to 70%, with amounts remaining
on the light side.
A warm front across the region on Wednesday brings considerable
uncertainty to max temperatures as models disagree in how far north
this front gets. Ample stratus cloud cover will limit diurnal
heating across the region, with NBM temps likely on the high side.
Temperatures across SW WI and NE IA are most uncertain with 25th to
75th percentile spread around 7-8 degrees F. With more cloud cover,
temps will likely remain in the mid to upper 40s. A cold front
swings through the region Wednesday night into Thursday as a low
pressure system passes to the north along the US/Canada border. This
will bring temperatures back into the low to mid 40s through the
rest of the week into the weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1000 PM CST Sun Nov 5 2023
Gusty southerly winds will subside slightly late tonight before
increasing again from the W/NW on Monday. LLWS will persist
through the early morning hours until winds aloft begin to
slacken. A window for MVFR ceilings exists through early Monday
morning (40-60% chance). A few showers are also possible early
Monday morning, particularly at KLSE, but probabilities are only
20-30% at this time, so have kept out for now. Some clearing is
possible early Monday, before additional SCT/BKN clouds spread
south towards I-90 through the day. The southern extent of the
thicker, MVFR ceilings, is lower confidence (40-50%) so have not
included any lower ceilings at this time.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...JAW
AVIATION...JM
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
250 PM PST Sun Nov 5 2023
.SYNOPSIS...A strong band of thunderstorms is likely to sweep
across the area from north to south later this evening.
Thunderstorms will be strongest along the Humboldt and Del nOrte
coasts with brief heavy rain and outflow winds over 40 mph. Showers
will gradually wain through early Monday morning with drier weather
mid week.
&&
.DISCUSSION...Today has brought a brief reprieve in rain showers and
gusty winds with even a couple hours of sun observed along the
Humboldt Coast late in the morning. The break will be short lived,
however, with the next round of showers already starting to produce
radar returns early this afternoon.
A deep low pressure system currently off the shore of Oregon is
expected to dip south overnight as an upper level trough quickly
digs along shore. Cold air building in aloft will build substantial,
elevated instability along and near shore, especially north of Cape
Mendocino. The HREF is showing 300 to 700 J/Kg of most unstable CAPE
all along the shore this evening. Furthermore, shortwave rotating
around the low pressure system will provide ample midlevel
convective triggers. Most convective allowing models show a strong
convective band making landfall as soon as 1900 this evening and
spreading south through the early morning hours. NBM is placing a
50% chance of thunder at any given point along the North Coast which
is much higher than most systems for this area.
Wind and severe storm risk....there will be substantial windshear in
the lower levels of the atmosphere, especially as a surface boundary
sweeps close to shore late this evening. HREF is showing low level
storm relative helicity in excess of 200 m/s which is generating
significant tornado parameters up 0.8. While marginal in absolute
terms, these values are high for this area climatologically. This
indicates the strongest storms this evening could produce water
spouts and possibly weak landfalling tornados. The chances are
greatest in the coast plains near Crescent City and around Cape
Mendocino where helicity is enhanced by the terrain. Shear will be
strongest tonight between around 1900 and 0300 Monday morning.
Overall the shear profile is sufficient to organize a line of
thunderstorms with possible embedded cells. Beyond waterspouts, the
storms will be capable of produce gusty outflow winds up to 50 mph.
Outside of storms, NBM is placing an 80% chance of high elevation
gusts in Humboldt and Del Norte exceeding 30 mph, but essentially no
chance of gusts over 40 mph. While thunderstorms may warrant their
own warning, the general wind speeds do not justify any wind
products. Though showers will likely continue through the day on
Monday, their intensity and wind potential will be much reduced
versus overnight.
Heavy rain risk...Precipitable water across the area is marginal at
best with no more than 1.0 inches expected anywhere. This lower
moisture is typical of a colder airmass with little tropical
influence. That said, thunderstorms will greatly increase
precipitation efficiency and HRRR has put 1 hour rain rates in excess
of 1 inch in Del Norte and Humboldt Counties. Coverage of higher
rain rates will likely be much higher than normal (not just
attached to the highest terrain) especially if an organized squall
line forms. With this said, a flash flood watch has been issued for
the Smith River Complex Burn Scar. Rain show intensity should
decrease early Monday morning. Though HREF and other models are
showing instability lingering Monday, decrease moisture will help
further scatter and decrease rainfall intensity through the day. In
total, Humboldt Bay will most likely see and additional 1.2 to 2.2
inches of rain with 3 to 5 inches in Del Norte. Though the focus has
been further north, there is an 80% chance that even southern
Mendocino and Lake counties will receive 0.8 inches of rain by the
end of Monday. Despite the cold air, snow levels staying above 4500
ft will limit any winter weather concerns, though heavy snow is
certainly possible on the highest peaks of the Trinity Alps
Showers will gradually dissipate on Tuesday with no more accumulating
precipitation by early Tuesday morning. Cold air settling over the
Great Basin will promote gentle offshore flow midweek, bring a
welcome reprieve to wet weather. Skies will most likely clear even
along the coast by Wednesday morning, though recent rain will likely
promote widespread fog in near coastal valleys. Where fog and cloud
allow, patchy frost is likely to return to the interior as early as
Tuesday morning, but spreading much more in coverage Wednesday and
Thursday morning. 80% of ensemble members show another cold system
and associated rain showers and possibly thunderstorms moving in
around Friday. Only about 20% of the ensemble members show a system
of comparable strength to the current one with lighter rain more
likely. /JHW
&&
.AVIATION...Ceilings are lifting to MVFR levels this afternoon,
with also periods of VFR. Showers are moving in ahead of a strong
frontal system. Heavy showers to an isolated thunderstorm may impact
the terminals in the near term this afternoon. Showers will increase
in intensity into the evening, followed by a transition to
thunderstorms. Some storms will be marginally severe, capable of
strong wind gusts from ACV to CEC tonight into Monday morning. VCTS
has also been included at UKI. LLWS will also develop at ACV and CEC
from SW winds aloft, at around 35kt from 1500 to 2000 ft AGL.
Ceilings will settle back to MVFR levels overnight, with TEMPO to
carrying IFR likely, especially with the heavy showers and
thunderstorms.
&&
.MARINE...Southerly winds are increasing across the waters this
afternoon in advance of a strong front. There is abundant being
consistently observed well offshore. This activity will advance east
into our waters into the early evening. Some thunderstorms will be
marginally severe, capable of gale strength wind gusts in excess of
40 kts and waterspout formation. Organized storm lines will also be
possible in this environment. See the current Marine Weather
Statement. The biggest threat is from this evening into Monday
morning, but an extension of the statement may be required for at
least portions of the waters later into Monday with the potential
for additional stronger thunderstorm formation. The Small Craft
Advisories were extended to cover the convectively enhanced
southerly winds associated with the front, as well as for seas that
have been stubborn to drop below 10 feet in most zones today.
Midday on Monday the next post frontal swell starts to move into the
waters, quickly building to 10 to 12 feet at 13 seconds by Monday
evening. Seas will remain elevated into Tuesday and then diminish
Tuesday night. This swell is expected to linger through the period,
but will be fairly small.
Monday night the winds start to switch around and become northerly.
These will increase through the day on Tuesday peaking around 15 to
25 tuesday night. Wednesday the northerly winds are expected to
gradually diminish. Late in the week another front is expected to
bring additional southerly winds although there is still quite a bit
of discrepancy on the strength and timing between models. MKK/JJW
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
Flash Flood Watch through Monday morning for CAZ102.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 10 PM PST Monday for PZZ450-470.
Small Craft Advisory from 9 PM this evening to 4 AM PST
Monday for PZZ455-475.
&&
$$
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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
526 PM CST Sun Nov 5 2023
.SHORT TERM...
Issued at 312 PM CST Sun Nov 5 2023
Through Monday night...
Main forecast messages:
* Breezy southerly to southwesterly winds overnight tonight into
Monday
* Unseasonably mild overnight tonight and Monday
* A slight chance for rain late overnight tonight/early Monday
morning, mainly in far northern Illinois
A low pressure system is in the process of slowly becoming organized
over the northern Plains this afternoon. By daybreak tomorrow, the
expectation is for a ~996 mb surface low to be centered over the
Arrowhead Region of Minnesota or the western tip of Lake Superior
with a warm front extending to its southeast and a cold front draped
to its southwest. A tightening pressure gradient in the vicinity of
this system will bring a period of breezy winds to the region,
initially from a southerly direction in our forecast area before
winds gradually veer southwesterly and later become more westerly
behind the system`s cold front. Gusts in excess of 30 mph are likely
at times on Monday, particularly during the morning hours, as we
start to mix into the low-level jet tucked into the system`s
southeastern quadrant. If the extensive cloud cover doesn`t end up
being too much of a impediment, then even occasional 40+ mph
gusts may be seen through about mid-day tomorrow morning before
winds gradually taper off over the course of the afternoon in
response to low-level pressure gradients loosening as the low
pressure system distances itself from our forecast area.
One consequence of the breezy southerly to southwesterly winds is
that it will feel unseasonably mild tonight and tomorrow. Tonight`s
lowest temperatures are actually expected to occur during the
evening before the breezier winds arrive and warm air advection
starts to ramp up, leading to rising temperatures overnight that
should largely be in the low to mid 50s by daybreak tomorrow.
Temperatures will continue to rise into the 60s going into the
afternoon, and some of our southern locales may even tag 70 as skies
start to clear out behind the passage of the cold front. While
cooler temperatures will lag behind the cold front, they will
eventually reach the area, bringing more seasonable low
temperature readings in the upper 30s to mid 40s to the area for
Monday night.
Last but not least, there is a possibility that a few locales see
a brief period of rain late overnight tonight or early tomorrow
morning. While the bulk of the precipitation associated with this
system will remain to our north closer to the system`s center
where the more pronounced forcing for ascent will be located,
pre-frontal warm air advection/isentropic ascent should help
saturate the tropospheric column here a good bit. This alone may
not be enough to spur the development of rain showers and/or
drizzle, but additional lift induced by DPVA along the southern
perimeter of an associated upper-level shortwave should provide
just enough assistance to generate rain showers along the leading
edge of an incoming EML plume. Modeled UVV in the latest HRRR and
RAP runs suggests that most of these showers would remain north
of the Illinois-Wisconsin stateline, but both models have
nevertheless recently been outputting QPF in our far northern
CWA, so have added an area of slight chance PoPs focused mainly
along and north of I-88 to account for this possibility.
Ogorek
&&
.LONG TERM...
Issued at 119 PM CST Sun Nov 5 2023
Tuesday through Sunday...
Key Points:
* Tuesday will be relatively quiet with a gradient in
temperatures across the area (warmest south) and partly cloudy
skies.
* Wednesday will be marked by scattered showers in the morning, a
stark temperature gradient in the afternoon (warmest south), and a
cold front in the evening.
* Shallow low-level moisture, strong capping, and weak forcing point
toward a mostly dry cold frontal passage Wednesday evening.
* Seasonable weather is on track to arrive Thursday through next
week.
Discussion:
Brief upper-level ridging between two short wavelength troughs will
move over the Great Lakes on Tuesday, setting the stage for a
relatively quiet day. The combined effects of partly cloudy skies,
light northeasterly winds off Lake Michigan, and the placement of a
stalled frontal boundary near US-24 will lead to a wide gradient in
high temperatures across the area tomorrow. Highs will range from
the mid 60s across central Illinois to the mid 50s near Interstate
80, and lower 50s near the Wisconsin border and Lake Michigan
shoreline. Winds will gradually turn easterly and clouds will
thicken Tuesday night in advance of the next upper-level shortwave.
Overnight lows will fall into the low to mid 40s.
Early Wednesday morning, the aforementioned stalled frontal boundary
is expected to lift northward as a warm front as the next upper-
level shortwave and associated surface low approach from the
southwest. Increasing warm-air advection atop the northward-moving
warm front will support scattered sprinkles or light rain showers
particularly during the morning hours. High temperatures on
Wednesday will depend on how far north the warm front lifts, which
depends on the track of center of the low pressure system. Even with
differences in individual model systems in the track and intensity
of the low (and WPC cluster analysis shows each cluster is heavily
sorted by individual ensemble suites), a "grand" mean of each shows
a track more or less from northeastern MO to northwestern IN. South
of the track, unseasonably warm 850mb temperatures of +12C and
broken clouds will support highs in the low to mid 70s, if not
warmer. Meanwhile, along and to the north of the track, highs will
be stuck in the upper 50s to around 60. For now, our official
forecast will show a somewhat smeared out gradient in temperatures,
which will no doubt get tightened up as the track is refined in
later forecasts.
As the low passes overhead Wednesday evening, a cold front will
sweep across the area from northwest to southeast. While the
synoptic pattern does bear some resemblance to those that support
cool-season thunderstorms, shallow low-level moisture, robust
capping at the base of a mid-level EML, and somewhat displaced upper-
level forcing well to our north suggest it may be difficult for
anything to develop along the front. With the GEFS showing the
furthest northwest/strongest low pressure system evolution compared
to the EPS/CMCE, we believe the GEFS-based CSU-machine learning
probabilities of 5-15% for a severe weather report somewhere in the
region on Wednesday are probably representative of an outlier
outcome at this point. With that said, we`ll still keep an eye on
model trends to determine if more aligned upper-level forcing or
higher-quality low-level moisture may be realized along/ahead of the
front.
Thursday and beyond look relatively quiet and quintessential of
early November (temperatures minus 5F of the average this weekend
and plus 5F thereafter; dry conditions). Successive runs of the
CMCE/GEFS/EPS suggest the pattern may become more active, at least
somewhere in the region, toward the end of next week.
Borchardt
&&
.AVIATION...
For the 00Z TAFs...
Aviation Forecast Concerns:
* LLWS develops overnight away from ORD/MDW, where surface gusts
will be more common.
* Gusty SW to WSW sfc winds Monday morning, with potential for a
period of 30+ kt gusts during the morning as we mix into low
level jet.
* MVFR ceiling potential Monday morning, with a few spotty showers
possible.
Surface low pressure currently over South Dakota will deepen and
move northeast to Lake Superior through Monday morning, in
response to a strong mid-level wave tracking across the region.
For the local terminals, the main impacts will be the development
of a strong 50 kt southwesterly low level jet tonight into early
Monday. With surface winds decoupling after sunset, this will
likely set up a period of low level wind shear (LLWS) conditions
with 45 kt winds just 1500 ft above the surface. KORD and KMDW,
typically a bit warmer within the Chicago urban region, will
likely develop surface gusts into the 20-25 kt range, which will
limit the magnitude of LLWS at those locations. Deepening of the
mixed layer after sunrise Monday morning will increase surface
winds as we mix into the lower portion of the low level jet. Wind
gusts near 30 kt are likely during the morning, and there may be a
brief window where 30+ kt gusts occur. The main core of the low
level jet will shift east of the area by midday/afternoon,
allowing wind gusts to ease a bit. Winds should continue to ease
and decouple Monday evening, and take on more of a westerly
direction.
Low level moist advection associated with the low level jet will
likely support development of VFR a cloud deck prior to morning,
and model guidance supports this lowering to an MVFR deck around
sunrise or shortly after. This should eventually rise and scatter
out to VFR by midday/early afternoon. There may be a period of
spotty showers early in the day the cloud deck develops, though
confidence is somewhat low at this point with models differing on
the depth of the available moisture.
Ratzer
&&
.MARINE...
Issued at 312 PM CST Sun Nov 5 2023
A deepening low pressure system passing to our north will bring a
period of breezy southerly to southwesterly winds over southern Lake
Michigan tonight through Monday. Wind gusts in the 20-30 kt range
may commence as early as the mid-late evening before gale force
gusts arrive closer to daybreak on Monday. Have hoisted a short
duration Small Craft Advisory to cover the approximately 3-6 hour
long period of breezy, but sub-gale force, winds preceding the 09Z/
3 AM CST start time of the going Gale Warning. The latest forecast
guidance indicates that gale force wind gusts may cease entirely by
18Z/noon CST on Monday, but for now, have left the original 21Z/3 PM
CST end time of the Gale Warning as is and will let that end time be
reassessed again in forthcoming forecast packages.
Ogorek
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...LMZ740-LMZ741-LMZ742...9 PM Sunday to 3
AM Monday.
Gale Warning...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM
Monday to 3 PM Monday.
Small Craft Advisory...LMZ743-LMZ744-LMZ745...midnight Monday to
3 AM Monday.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
706 PM EST Sun Nov 5 2023
.SHORT TERM...(This afternoon and evening)
Issued at 1222 PM EST SUN NOV 5 2023
Key message:
-Light showers will be possible this afternoon and evening.
RAP anaylsis and GOES water vapor imagery show a cluster of
shortwaves upstream in the northern Rockies with northwest flow
aloft stream into the Upper Great Lakes. At the surface, high
pressure ridging has shifted east, allowing warm air advection and
isentropic asent to gradually build into the region. This has
supported cloud cover across the region and some light radar
reflectivities in the west that may have supported some sprinkles
here and there. As we progress through the remainder of the day, the
wave of sprinkles/light radar reflectivies should lift northeastward
followed by continued midlevel isentropic asent and warm air
advection. Much like the overnight CAM runs, 12z and hourly guidance
continues to suggest saturation and some preceeding light precip
would be most likely across the south-central prior to 0z. However,
guidance continues to suggest the main forcing will move in
overnight.
.LONG TERM...(Tonight through Sunday)
Issued at 230 PM EST SUN NOV 5 2023
Key Messages:
-Some breezy winds and widespread light to moderate rain (0.25-1")
tonight into Monday.
-Gusty winds near 30-35 mph may support large enough waves to
support beach erosion and lakeshore flooding concerns in Schoolcraft
County. Lakeshore flood advisory issued.
-A mix of lake effect rain and snow showers follow Monday afternoon
into Tuesday.
-Clipper and cold front may impact the area Tuesday night through
Wednesday afternoon, supporting snow that transitions to a mix of
rain and snow.
-Lake effect rain and snow showers to end the work week.
A jumble of shortwaves upstream and an organizing surface low over
the Northern Plains are expected to press eastward into Lake
Superior by Monday morning. Ahead of the low, strong isentropic
forcing along with 40-50kt 700mb winds will support rain showers
across the forecast area tonight and Monday ahead of the low. QPF
among the various guidance packages suggest mostly a 0.25-1 inch
range, with the higher amounts being expected across the Keweenaw
and east. Increasing pressure gradient forces will also support some
breezy conditions upwards of 25 mph near Lake Superior and
potentially near 30-35 mph near Lake Michigan. The latter is likely
to result in large waves building on Lake Michigan that could lead
to some minor beach erosion or lakeshore flooding Monday morning.
With that in mind, I opted to issue a Lakeshore Flood Advisory for
Schoolcraft County for parts east of Manistique where 8 foot or
higher waves crashing onto the beach can`t be ruled out. The surface
low looks to pull away into Ontario Monday afternoon, but continued
shortwave support aloft along an inverted surface trough will allow
for continued showers near Lake Superior Monday night. With Lake
Superior running around +8C and the airmass building in behind the
surface low cooling to near -6C by midnight, showers should
transition from lake enhanced to lake effect overnight in the north
to northwest wind belts. The air column cooling should also support
some snow mixing in at times. Any areas that do transition should
not expected much more than an inch or so.
Surface high and drier air building eastward through Ontario Tuesday
should lead to decreasing shower activity through the morning hours.
By Tuesday evening, surface high east of the region while the ridge
axis aloft transitions through the region could complicate precip
timing and coverage ahead of the next clipper moving across the
Northern Plains. However, guidance moves the next round of weakly
isentropically forced precip into the region Tuesday night from west
to east. Depending on when the deeper moisture arrives and influence
of the drier easterly flow ahead of it, conditions may be cold
enough to see snow initially before changing over to a mix during
the day Wednesday. There`s good agreement that a surface low will
develop in the Central Plains, then lift northeast into southern
Lower or the Ohio River Valley. 0z and 6z guidance suggested
differences in the evolution of this and the clipper moving through
the Northern Plains, suggesting potential phasing of the two in the
Upper Great Lakes. However, the 12z packages suggest better
agreement now with the southern system staying south while the
clipper holds together as it transits Ontario and swings a cold
front through the forecast area Wednesday night. The result looks to
be precip moving through the area Wednesday followed by post frontal
lake effect once the colder air arrives to finish off the work week.
For ptype, a mix of rain and show showers should be expected, but
little impacts from any accumulations.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 706 PM EST SUN NOV 5 2023
Flight restrictions will prevail for the duration of the TAF period
as a low pressure system moves into the area. Widespread rain
showers will contribute to MVFR/IFR cigs and visibilities with
further deterioration to LIFR at IWD and CMX by tomorrow morning.
Also, a low level jet will create a LLWS threat in the Mon 06-10Z
time frame at all TAF sites. At the surface, southerly winds will
gust up to 26 kts, especially at IWD.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 230 PM EST SUN NOV 5 2023
An approaching clipper system from the west will result in an
increasing pressure gradient across Lake Superior beginning this
evening. Ahead of the low, guidance noses in a stout low level jet
into eastern Lake Superior after midnight tonight that could linger
into Monday morning. There`s a window where the jet will be present
while overlake instability exists, which would support mixing
stronger winds down to the surface. Probabilistic guidance suggests
upwards of a 50% chance of realizing gales in eastern Lake Superior.
With all these factors considered, opted to issue a Gale Warning for
the eastern zones into Monday morning. As the low transits the lake
during the day Monday, a period of low westerly winds is expected
before increasing to 20-30kts from the north for Tuesday night.
Lighter winds of 20kts or less return Tuesday as high pressure
transits Ontario. However, the next system follows
Wednesday/Thursday. Overall, with better model agreement between the
overnight and morning guidance packages, there`s medium confidence
(50%) of southeasterly winds climbing upwards of 30kts before a cold
front moves west to east through the lake Wednesday night. There`s
still uncertainty though about the post frontal westerly winds, and
some models are suggesting a strong gale can`t be ruled out
Thursday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Lakeshore Flood Advisory from 7 AM to 1 PM EST Monday for MIZ014.
Lake Superior...
Gale Warning from 3 AM to 10 AM EST Monday for LSZ250-251-266-
267.
Lake Michigan...
Gale Warning from 1 AM to 10 AM EST Monday for LMZ221-248-250.
&&
$$
SHORT TERM...JTP
LONG TERM...JTP
AVIATION...TDUD
MARINE...JTP
Area Forecast Discussion
National Weather Service Reno NV
1249 PM PST Sun Nov 5 2023
.SYNOPSIS...
Strong winds will continue through the night and Monday, with
rain showers becoming more numerous during the day Monday. Some
snow may cause travel impacts over the Sierra Monday late
afternoon and night. From Tuesday afternoon onward, including the
Veteran`s Day weekend, relatively quiet weather is expected for
most areas. A few mountain snow showers are possible Friday.
&&
.DISCUSSION...
* Areawide strong winds will continue through tonight and into
Monday in response to 140 knot upper jet and 50 knot mountain
top flow. Slight increase in the wind forecast, but overall a
just under advisory event with most areas seeing gusts 30-45 mph
with the typical wind prone spots seeing gusts 50-60 mph for
periods of time. This includes Washoe Valley, 395 in Lassen &
Mono Counties, and maybe 95 at Walker Lake. Winds will likely
not let up much tonight except in the most sheltered of valleys.
* Rain and snow showers will increase in coverage Monday into
Monday night. We`re within the time horizon of the HRRR/HREF and
both of those are showing potential for a period of up to
1"/hour snow rates near the Sierra crest from Donner southward
into the E Sierra late Monday afternoon into the night. Very
convective looking environment too, so that limits
predictability but also creates a larger boom/bust scenario.
Either way we`re messaging potential snow travel impacts over
the Sierra passes late Monday into the night, including the
evening commute (earlier sunset too). A few light flurries/snow
showers may persist into Tues morning, even down to about 5500`
in W Nevada foothills.
* Tuesday afternoon onward looking relatively cool and quiet with
more limited valley mixing and ventilation. Still potential for
a very quick/weak storm to bring light snow showers to the
mountains on Friday. NBM guidance showing about a 10% chance of
1" in the mountains.
* Storm door remains at least slightly ajar into the week two
period. CW3E atmospheric river landfall tools, especially the
GEFS, showing potential for Pacific storms 11/14-18 timeframe.
ECMWF EPS less so. Based on NBM temperature/snow level
projections out that far, any storms would be of the average to
cooler-end on the spectrum.
-Chris
&&
.AVIATION...
* With mountain top flow nearing 50 knots and jet stream speeds
near 140 knots, expect increased turbulence, wind shear, and
mountain wave activity through Monday. Already seeing winds
gusting to 80-95 mph along the ridges.
* Surface winds will ramp this afternoon into early Monday with
persistent breezes through the night tonight. Gusts on the order
of 25-35 knots will be common, with a 1 in 4 chance (25%) of
seeing gusts exceed 40 knots per NBM guidance at RNO and MMH for
example.
* Precipitation impacts through tonight will be confined to far
NE California (SVE) with occasional MVFR showers. Rain/snow
showers become more widespread Monday with a better bet for
seeing occasional MVFR/IFR conditions and mountain obscuration
areawide, including RNO/TRK/TVL/CXP/MEV, and even as far south
as MMH Monday night.
* Snow accumulations can`t be ruled out for TRK/TVL Monday
evening/night with NBM showing 20-40% chance of 1" and even a
10% chance of 2". Latest HRRR shows a very convective
environment so snow showers will be hit/miss but if they hit
then quick accumulations and LIFR conditions are a good bet.
Snow risk for MMH is less certain but not-zero.
-Chris
&&
.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory until 4 PM PST Monday for Lake Tahoe in
NVZ002.
Winter Weather Advisory from noon Monday to midnight PST Monday
night NVZ002.
Lake Wind Advisory from 1 AM to 4 PM PST Monday for Pyramid Lake
in NVZ004.
CA...Lake Wind Advisory until 4 PM PST Monday for Lake Tahoe in
CAZ072.
Winter Weather Advisory from noon Monday to midnight PST Monday
night CAZ072.
Winter Weather Advisory from 3 PM Monday to 3 AM PST Tuesday
CAZ073.
&&
$$
Area Forecast Discussion
National Weather Service Shreveport LA
1004 PM CST Sun Nov 5 2023
...New UPDATE...
.UPDATE...
Issued at 1004 PM CST Sun Nov 5 2023
The evening RGB satellite imagery indicates an extensive cirrus
shield has overspread much of the region, with the leading edge of
a cu field continuing to shift NNE across SE OK and the Nrn
sections of SW AR along a 25-30kt SWrly flow on the Ern edge of
the stronger LLJ over the Srn Plains. Meanwhile, sfc ridging
remains anchored over the Gulf States into the Lower MS Valley,
with enough of a pressure gradient to maintain light SSE winds
over E TX and SW AR. These in tandem will result in milder temps
tonight that just 24 hrs ago, and is already evident as the 03Z
temps are running some 3-8 degrees warmer than this time last
night. In addition, the fact that the cirrus shield should
continue to thicken overnight, while lower stratocu cigs develop
late over portions of E TX/SE OK/adjacent SW AR, temps should
eventually level off or even rise slightly over these areas late.
The latest HRRR remains persistent with area of FG developing late
tonight across portions of extreme SE TX and much of S LA where
the cirrus shield is thinner, while slowly advecting N into Cntrl
LA by daybreak. Did hold off an FG mention across the Srn zones
since it is a bit slower and not as bullish advecting into these
areas, but will allow the mid shift to monitor and add FG mention
if needed with the next forecast update. Did beef up the sky grids
though to reflect the thickening cirrus shield and additional low
cigs late, with only very minor tweaks needed to the min temps
based on the 03Z obs. Otherwise, the remainder of the forecast is
on track.
Zone update already out...grids will be available shortly.
15
&&
.AVIATION...
(00Z TAFS)
Issued at 544 PM CST Sun Nov 5 2023
VFR conditions will continue this evening through at least a
portion of the overnight hours, as some fair wx cu will linger
beneath an extensive cirrus shield that continues to spill E
across the region. Low MVFR cigs may develop after 09Z Monday
across portions of NE TX/SE OK, possibly affecting the E TX/TXK
terminals, with even areas of FG developing across SE TX/S LA and
slowly advecting N into Deep E TX/Cntrl LA by/shortly after 12Z.
Not entirely confident of the coverage through given the extensive
cirrus cigs overhead, and whether it will reach LFK, and thus have
remained conservative with vsbys and held off on introducing LIFR
cigs and will re-evaluate for the 06Z TAF issuance. The lower cigs
that should develop late tonight should linger through much of the
morning Monday, before eventually scattering out by midday/during
the afternoon. The cirrus cigs should also gradually diminish from
NW to SE as well during the afternoon, but linger across E TX/N LA
through much of the day. Light SSE winds tonight will become SSW
and increase to 8-12 kts after 15Z, with gusts to 22kts possible
over E TX/adjacent SW AR/extreme NW LA. /15/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 58 84 64 84 / 0 0 0 0
MLU 51 85 59 85 / 0 0 0 0
DEQ 56 81 58 79 / 0 0 0 0
TXK 60 81 62 81 / 0 0 0 0
ELD 53 82 60 81 / 0 0 0 0
TYR 62 82 65 83 / 0 0 0 0
GGG 61 83 64 84 / 0 0 0 0
LFK 59 83 64 85 / 0 0 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...15
AVIATION...15
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
410 PM MST Sun Nov 5 2023
.DISCUSSION...(This Evening Through Sunday)
Issued at 1205 PM MST Sun Nov 5 2023
Key Messages:
- Breezy/windy this afternoon and evening with frontal passage
- Mostly dry through the workweek with a slight cooling trend
Tuesday through Friday
A potent short-wave trough was moving across southern MT and
northern WY this afternoon, which was associated with strong lift
and even some convection/lightning. A lee surface trough was from
eastern MT through far eastern WY, and a Pacific cold front was
moving into central MT. Warm, dry, and windy conditions were
across parts of the southwestern and southern CWA, resulting in
elevated fire-weather conditions. In general, the models and
ensembles agree well through about Wednesday, but then there is
notable divergence with the upper pattern thereafter.
The short-wave trough and associated Q-G forcing for lift will move
across the northern CWA fairly rapidly this afternoon and evening.
The gusty west/southwest winds over parts of the area ahead of the
front will become northwest behind the front with gusts to around 40
mph late this afternoon through this evening. The HREF and NBM
ensembles maintain sub-advisory wind, which is supported by 2-4
mb/3hr pressure rises progged by the various models. Given the
midlevel lapse rates of 7-7.5 C/km and some virga or scattered
light rain showers (mostly over the northern half of the CWA),
some locally gusty winds of 40-50 mph will be possible, consistent
with the time-lagged HRRR runs. Also, would not be surprised if
the GLM shows a few lightning flashes, but the CAPE is near zero
so have not put thunder in the forecast. By 06z this system should
mostly be east of the CWA.
The rest of the week will feature progressive flow with some
troughing on Tuesday-Wednesday. However, Q-G forcing will be minimal
and thus do not expect much in the way of precipitation chances.
Another frontal passage is advertised early Wednesday, which may
bring another period of breezy winds. Otherwise, the 6-14 day
outlook continues to favor odds of above-average temperatures and
below-average precipitation.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Monday Evening)
Issued At 404 PM MST Sun Nov 5 2023
Rain showers associated with a front will continue to move from
west to east across western SD. Strong winds with gusts up to
45kts and locally MVFR conditions can be expected in and around
these showers. Shower activity should move out of the CWA by 03z
Otherwise, VFR conditions expected through the TAF period.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION...Bunkers
AVIATION...Wong