Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/31/24
Area Forecast Discussion
National Weather Service La Crosse WI
719 PM CDT Wed Oct 30 2024
.KEY MESSAGES...
- A stronger storm or two still possible this evening, with
heavier rain threat lingering into tonight. Rainfall amounts
in excess of 2 inches possible south and east of La Crosse.
- Dry through Saturday, Active Pattern Sunday into Next Week
with Precipitation Chances Sunday through Tuesday
&&
.DISCUSSION...
Issued at 312 PM CDT Wed Oct 30 2024
Tonight into Thursday: A Stronger Storm or Two with Heavier Rain
Today`s anticipated cold front ended up moving in faster than
originally expected, which has diminished the overall thunderstorm
coverage as well as the severe weather potential this
afternoon/evening. The upper level wind pattern is nearly parallel
along and ahead of the front, which brings a training thunderstorm
with heavy rain potential overnight. Overall, the general thinking
is that a stronger storm or two remains possible, but the overall
chances have diminished some. Model soundings suggest there isn`t
much CAPE aloft that would support a mentionable hail threat, but
with a LLJ axis shifting north into the area tonight, stronger winds
will remain possible within the area of rainfall. Overall rainfall
amounts have come down around 20% or so with the latest CAMs this
afternoon; however, the overall message of 1 to 2 inches with
locally higher amounts across parts of SW WI and NE IA possible
remains in play.
Latest updates shows around 1000 J/kg MUCAPE along the frontal axis,
with the strongest shear along and behind the front. With these two
disconnected some, the overall severe chances remain lower. Surface-
based CAPE values are even lower, around 500 J/kg per the latest
RAP, however the surface dewpoint values within the RAP are up to 4
degrees too high.
As for heavier rain threat...the overall precipitation amounts range
from around 1 to 2 inches across our area, generally increasing to
the SE. The best chances for locally higher amounts along along the
frontal axis from roughly Oelwein to Mauston. Probabilities for 2+
inches per the NBM range from 40 to 70% from La Crosse to the SE
through Thursday. For 3+ inches, these chances decrease to around 10
to 30%. With this precipitation occurring over 6+ hours and the
recent dry weather, thinking overall flash flood threat is low.
River rises are expected, but the latest probabilities for river
flooding remain around 10% or lower at this time for rivers east of
the Mississippi.
This Weekend into Early Next Week: More Active, Precipitation
Chances Return Sunday into Tuesday
Medium range models are in good agreement for the overall pattern
evolution into this weekend as a more active, amplified pattern
takes over. Ensembles suggest a deep, western CONUS trough with a
building ridge axis to the east. In the middle, there will be
persistent precipitation chances from Sunday into Tuesday across the
Midwest. The best chances for precipitation remain off to our south
for the heaviest amounts, but overall chances for precipitation
Sunday into Tuesday for our local area will remain around 50 to 70%,
with best chances south of I90.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 656 PM CDT Wed Oct 30 2024
A southwest to northeast oriented precipitation axis at 31.00Z
TAF issuance covers the forecast area from northeast Iowa,
southeast Minnesota, and western into central Wisconsin with
highest reflectivity (i.e., heavier precipitation) along our
southeastern counties in southwest Wisconsin; south of the
frontal boundary. To the northwest of this boundary a colder
airmass is filtering in, ushering in IFR ceilings. The
associated low center currently (31.00Z) in southwest Iowa is
slowly trudging to the east-northeast and will perpetuate these
conditions.
Eventually the low center advects over the forecast area through
the early morning hours (31.06-31.12Z), rotating winds
anticyclonically (clockwise) in the process. A temporary
reprieve in the heavier precipitation and lowest flight
conditions is expected during that time. Higher impact (i.e.,
lower flight conditions) expected at KRST given the persistent
conditions. Any increase in ceilings is short lived as the low
stalls, deepens, and wraps cold air advection anticyclonically
primarily into central Wisconsin and southeast Minnesota.
Therefore, IFR potential increases through Thursday morning from
the cold air advection. Precipitation chances also increase
primarily along our northwestern half from southeast Minnesota
through western Wisconsin. Therefore of the two TAF sites,
higher confidence for persistent impacts expected at KRST
instead of KLSE. A more confined area of heavier precipitation
may impact KLSE through the early afternoon with IFR-LIFR
ceilings/visibilities but again less confidence. Thunder chances
are too low at 31.00Z TAF issuance to include for either TAF
site. The greatest flight impacts (i.e., LIFR) and thunder
potential may need to be adjusted in future amendments or
31.06/31.12Z TAF issuances. Highest confidence for lifting of
any restrictions are near or slightly after 31.00Z TAF terminus.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...JAW
AVIATION...JAR
Area Forecast Discussion
National Weather Service Columbia SC
708 PM EDT Wed Oct 30 2024
.SYNOPSIS...
Upper ridging and southeast winds will result in a warming
trend for the region through Friday. A passing trough and dry
cold front drop temperatures this weekend slightly. The ridge
builds back stronger early next week with another warming trend.
Dry conditions are likely to continue through the next seven
days.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Key Message(s):
- Fog development possible once again tonight.
Skies will be mostly clear overnight. There is still some shallow
low-level moisture over the region from weak onshore flow. With
clear skies, light to calm winds, and mostly ideal radiational
cooling, fog development is once again expected late tonight.
Guidance is still somewhat mixed on the potential for dense fog,
especially if the low-level jet remains later tonight. Crossover
temperatures from this afternoon looked to be around 60
degrees, and with overnight lows forecast in the mid to upper
50s, dense fog is possible again by morning.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Key Message(s):
- Warm conditions expected Thursday. An isolated shower is
possible late Friday towards the coast.
After another foggy start, ridging aloft will continue to build
on Thursday with high temps climbing into the 80`s. Southeast
winds will remain in place and help reinforce the elevated low
level moisture with some wind gusts 15-20 mph likely. Given the
current pattern with strong ridging aloft and surface high
pressure to our northeast, morning fog looks likely again Friday
morning. Some elevated PWAT`s will move onshore Friday as the
ridge weakens slightly thanks to a sharp trough moving across
the Great Lakes. So a few isentropically forced showers are
expected in the coastal plain, may be into the eastern Midlands,
Friday afternoon. High temps again will climb into the 80`s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Key Message(s):
- Dry and warm throughout the long term period.
Deep ridging aloft will generally remain in place over the
Southeast US throughout the long term into next week. The ridge
will flatten several times during the period as shortwaves slide
over the Great Lakes, but heights and temps will remain above
average throughout the period based as GEFS NAEFS. Rain chances
again remain very low for the forecast period based on the
current ridge axis setup and the lack of moisture available
across the entire Southeast basin.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
With moist, onshore flow over the region restrictions should
develop once again tonight. Particularly in the CSRA where a SE
wind up the Savannah River Valley is climatologically favorable
for fog. The HRRR and LAMP guidance also favor fog formation,
however with a 20 to 25 kt LLJ shown in the the NAM and GFS
time-heights it seems more reasonable that stratus would be
favored with patchy fog possible or stratus building down and
reducing visibilities. Overall, at least patchy MVFR/IFR
restrictions are likely if not widespread restrictions.
Confidence in restrictions are highest at AGS. Expect improving
conditions by mid to late morning with another cumulus deck
develop around 4 kft. Winds on Thursday will be out of the south
from 5 to 10 kts.
EXTENDED AVIATION OUTLOOK...Periods of restrictions likely
Friday and over the weekend as a front moves into the forecast
area then stalls just to our south.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
926 PM MDT Wed Oct 30 2024
.KEY MESSAGES...
- Winter weather is ongoing across much of the area. Snow and
rain showers will continue this afternoon and into the
evening.
- Potentially brief high winds possible over the wind prone
areas of southeast Wyoming late Wednesday night into Thursday
morning.
&&
.SHORT TERM /THROUGH FRIDAY/...
Issued at 257 PM MDT Wed Oct 30 2024
Observations continue to show light rain and snow showers across the
CWA. These scattered showers will continue through the afternoon but
decrease in coverage through the evening hours. Hi-Res guidance,
especially the HRRR shows a fairly large swath of precipitation
moving over the South Laramie Range and into Laramie County this
evening. QPF amounts could be rather impressive with this swath of
precipitation, so cannot rule out some snow accumulation in Laramie,
Cheyenne, and the South Laramie Range. With brief upslope flow in
Laramie at the time of precipitation, an inch of snow accumulation
could be possible. As snow moves into the South Laramie Range,
higher QPF amounts and a bit more prolonged precipitation could lead
to a quick 1 to 3 inches of snow. Finally, once the snow moves into
Cheyenne, higher QPF amounts could also lead to accumulations of an
inch or more. Snow should be done in Laramie County by about 10 PM.
Overnight, winds will gradually increase over the usual southeast
Wyoming wind prones. The exiting trough will allow a surface high to
build in western Wyoming, while a weak surface trough sits just east
of the Laramie Range. This will increase MSLP gradients over the
western zones slightly. Even CAG-CPR 700 mb height gradients are not
all that impressive, with values around 45 meters early Thursday
morning. The main variable driving the windy conditions will be
strong winds aloft. 700 mb winds will max out around 700 mb, with
fairly good subsidence over the wind prones. It will definitely be
windy, with wind gusts over 50 MPH, but not sure if gusts will hit
criteria for high winds. In-house guidance does give the Arlington
zone about a 50 percent chance at seeing high winds, however, did
not have the confidence to upgrade the current High Wind Watches to
Warnings as this event looks marginal.
The rest of Thursday looks uneventful. The day will start off chilly
with most locations seeing low temperatures Thursday morning in the
upper teens to low 20s. Temperatures will warm throughout the day,
reaching about average for Halloween for most areas. However, the
breezy conditions will likely make temperatures feel cooler than
they actually area. Trick or treating Thursday evening will
definitely be on the chilly side! Friday marks the start of November
and looks like a repeat of Thursday. Expect another breezy day as an
upper-level shortwave moves across the CWA. Temperatures will be
slightly warmer, with closer to average highs during the day.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 257 PM MDT Wed Oct 30 2024
The active synoptic weather pattern continues into next week with a
series of fairly potent upper level troughs passing through the
area. As the next trough dives into the west, the downstream ridge
over the central and eastern CONUS will amplify, supporting a fairly
mild weekend. Potent warm air advection in advance of the trough
will push 700-mb temperatures to around +4-5C in the southeast part
of the forecast area, and around 0 to +2C in the northwest part.
This should be enough to get highs above normal for most of the
area, although the Rawlins to Douglas corridor may be near or
slightly below. While temperatures aloft look decent for warmth,
southeast winds over the High Plains and plentiful cloud cover will
likely keep temperatures from reaching quite as high as the could
otherwise. Sunday looks like a fairly dynamic day as the potent
longwave trough arrives. Southwest flow in advance of the trough
will initiate lee cyclogenesis over eastern Colorado, which will
strengthen through the day on Sunday. A strong cold front will
simultaneously come down from the northwest, merging into the
surface cyclone by Sunday evening. The frontal passage is currently
expected sometime in the afternoon, and thus highs for Sunday are
near average again. However, there is some bust potential on this if
the front comes through just a few hours earlier before peak heating
and knocks down temperatures for the afternoon.
Model guidance has come into much better agreement today regarding
the next storm system in the Sunday/Monday time period. Overall, it
now looks like the strong, partially closed low solution will be the
most probable outcome, although there is still some variability in
the exact strength and depth of the trough as it moves through. The
lift profile in this system looks pretty messy at this time. We`ll
have some frontogenesis present with the initial frontal passage
that persists with the cyclogenesis to the south, but current model
guidance shows the low struggling to develop a clear wrap-around
flow thanks to the partial connection to the parent trough to the
north. As a result, most ensemble members show light to moderate QPF
Sunday afternoon into Monday morning in the 0.1 to 0.25" range.
Precipitation type looks to be mainly snow in Wyoming, and rain
transitioning to snow in Nebraska. A few outlier ensemble members
show the frontogenesis stronger over the I-80 corridor, allowing for
a higher end scenario near warning criteria in this area, but the
probability of this is fairly low at this time (10%). Tuesday looks
like a transition day in between two shortwave troughs, though it
could be windy. About 20% of ensemble members indicate 700-mb winds
pushing 50 knots over Cheyenne in the west to northwest flow behind
the departing trough. For now, nudge wind speeds up slightly, but
too much uncertainty is present to go much further than that.
Another trough is expected to arrive around Wednesday. Most ensemble
members keep this second system as a more clipper-type progressive
open wave, but there is a possibility of it closing off over the
southwest again.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 856 PM MDT Wed Oct 30 2024
A trough aloft will move to the east of the region overnight,
with west southwest flow aloft strengthening on Thursday.
Wyoming TAFS...Ceilings will be near 3500 feet until 08Z, then
skies will be mostly clear. Winds will gust to 32 knots at
Rawlins from 08Z to 00Z, and to 26 knots at Laramie and Cheyenne
from 14Z to 00Z.
Nebraska TAFS...Scattered to broken clouds from 2500 to
5000 feet will occur until mid morning, with occasional fog
reducing visibilities to 2 miles and ceilings under 500 feet at
Scottsbluff and Alliance from 08Z to 13Z. Then skies will be
mostly clear. Winds will gust to 22 knots at Alliance and Sidney
from 16Z to 00Z.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch from midnight MDT tonight through Thursday
morning for WYZ104-106-110.
NE...None.
&&
$$
UPDATE...TJT
SHORT TERM...SF
LONG TERM...MN
AVIATION...RUBIN
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1047 PM EDT Wed Oct 30 2024
.KEY MESSAGES...
- Southwest wind gusts of 30 to 40 MPH are expected this afternoon
and early evening. On Thursday, wind gusts of up to 50 MPH are
possible during the afternoon and evening - especially across the
Saginaw Valley and Thumb regions.
- Numerous showers and a few thunderstorms Thursday afternoon in
advance of a strong cold front.
- Much cooler weather Friday and Saturday with temperatures in the
40s and 50s.
&&
.AVIATION...
Southwest winds will gust to 20 or more knots at times overnight
with another gusty day expected Thursday as strong mixing occurs in
advance of approaching cold front. Expect gusts to 30 or more knots
with the strongest winds over KMBS by afternoon. Moisture will also
increase within this southwest flow regime with MVFR to lower VFR
cigs and scattered convection. While most activity will be in the
form of showers, a few rumbles of thunder will also be possible
during the afternoon/early evening. Gusty winds will continue into
the evening as fropa occurs and downward momentum with the passage
of this front will likely lead to several hours of enhanced gusts.
For DTW/D21 Convection...There is a low chance of a thunderstorm
Thursday afternoon/evening as weak instability develops within plume
of higher moisture.
DTW THRESHOLD PROBABILITIES...
* Low for ceiling 5000 ft or less by Thursday morning, medium
by Thursday afternoon.
* Low for thunderstorms Thursday afternoon and evening.
&&
.PREV DISCUSSION...
Issued at 328 PM EDT Wed Oct 30 2024
DISCUSSION...
Amplified longwave ridging across eastern North America continues to
drive near record warmth across the region. Under filtered sun and
strong low-level warm advection temperatures have climbed near or
eclipsed the record values for the date. The deep southwesterly flow
will maintain anomalously warm conditions through Thursday - though
not enough to challenge records.
A significant weather making system is currently deepening over the
central Plains and will advance northeast into the northern Great
Lakes Region by late Thursday. A strong cold front associated with
this system will cross Southeast Lower Michigan during the mid-late
afternoon hours tomorrow. Predictability of the finer, higher
amplitude features of this system has been rather low - owing much
of the uncertainty to the influence of the ongoing deep convective
response. Guidance tendencies have been toward quicker development
tonight, which favors a slightly farther west solution - then an
earlier filling process and fast emergence into the main westerlies
over eastern Canada on Friday.
This paced evolution will result in a reduction of sustained
moisture transport in the southern Lakes Region during the day
Thursday. Additionally, the anti-cyclonic side of the low-level jet
will remain longer - squashing larger scale precipitation
organization. There are strong indications that deep saturation will
be challenged across Southeast Michigan in the pre-frontal airmass -
leading to showery conditions in the few hours ahead of the front.
Instability production via differential advection will have faded by
then, as well; therefore, CAPE values and depth will be meager.
There is a sliver of forcing directed toward convective initiation
with enough dynamic trapping in the convective layer right along the
front, as indicated by CBL Froude Number near 1, to support a broken
line of forced convection. Given the strength of the front, the
resultant intensity should be greater than one would expect with
less than 500 J/kg of CAPE. Furthermore, winds will become strong
and gusty through the course of the day - with greater than 50 knots
residing at 850-mb supporting frequent gusts over 40 mph.
Since the main wave will complete the deepening phase just upstream,
there are dynamic ramifications in the sector of the system that
will affect the central portions of Lower Michigan. Namely, a pocket
of negative geopotential flux emerges to the right of the QG height
fall region - suggesting a mid-level mass release to the east should
be expected. This release will support an acceleration to the low
level isentropic surfaces and possibly support an inertia-gravity
wave response, as the jet level flow will become unbalanced.
Moreover, the system relative flow becomes more orthogonal to the
isentropic cliff - supporting dynamic downward momentum transport.
There are also indications in the RAP solutions that the flow along
the leading edge of the isentropic downglide will become unbalanced,
offering a couple hour window for higher wind gust potential along
the front and during the most aggressive post-frontal cold
advection. With 50 knots within easy reach just off the surface,
gusts to 50 mph will be possible where these conditions line up -
currently projected across the Saginaw Valley and Thumb regions
during the late afternoon and early evening. Winds will settle
quickly overnight Thursday night as the strong near surface cold
advection introduces an inversion layer that will insulate the
surface layer from the higher momentum aloft.
A day or two of chill will follow with highs only in the low 50s on
Friday and mid to upper 50s on Saturday. Clouds and rain chances
increase on Sunday as the long wave ridge over the southeast CONUS
builds and moist return flow washes into the region. Early next
week, the majority of the global ensemble membership maintains the
deep anticyclonic flow and above average lower tropospheric
temperatures. The continued deep southwesterly flow will support a
steady flux of moisture through the Mississippi Valley into the
Great Lakes region - establishing a rather wet period. There is a
small camp (about 15% of the solutions) that compress the longwave
train and point toward more aggressive response by the middle of
next week - possibly breaking down the long wave ridge.
MARINE...
The stalled cold front is still to our west extending from eastern
Ontario down into Oklahoma and West Texas. A new strengthening low
is developing over the southern Plains today that will lift
northeast through the western Great Lakes on Thursday which will
then push the cold front through the local area in the afternoon and
evening. Gusty southwesterly winds continue today peaking around 20
to 25 knots over the waters although stronger winds to 30 knots are
occuring over land due to more unstable conditions. This will
continue into Thursday as we remain in the unseasonably warm airmass
out ahead of the front. Small Craft Advisories are in effect and
will continue through the overnight with the elevated winds and
waves persisting. The cold front then brings showers on Thursday
with moderate winds shifting northwest in its wake by Friday. The
unstable cooler air behind the front may result in winds gusting to
near gale force Thursday night into Friday morning. A Gale Watch is
in effect for all of Lake Huron as a result. High pressure quickly
returns by late Friday leading to light winds.
CLIMATE...
The record highs for Today, October 30th.
Detroit: 76 Degrees (Set in 1999)
Flint: 77 Degrees (Set in 1950)
Saginaw: 76 Degrees (Set in 1999)
The record highs for Thursday, October 31st.
Detroit: 79 Degrees (Set in 1950)
Flint: 78 Degrees (Set in 1950)
Saginaw: 79 Degrees (Set in 1933)
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Gale Warning from 8 PM Thursday to 10 AM EDT Friday for LHZ361-362.
Gale Warning from 2 PM Thursday to 4 AM EDT Friday for LHZ363-421-
422-441>443-462>464.
Small Craft Advisory until 2 PM EDT Thursday for LHZ421-422-441>443.
Low Water Advisory from 8 PM Thursday to 4 AM EDT Friday for LHZ422.
Lake St Clair...Small Craft Advisory until 10 AM EDT Friday for LCZ460.
Michigan waters of Lake Erie...Small Craft Advisory until 10 AM EDT Friday for LEZ444.
Low Water Advisory from 8 PM Thursday to 8 AM EDT Friday for LEZ444.
&&
$$
AVIATION.....DG
DISCUSSION...Mann
MARINE.......DK
CLIMATE......Mann
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
705 PM CDT Wed Oct 30 2024
...New AVIATION...
.SHORT TERM...
(Tonight through Thursday night)
Issued at 240 PM CDT Wed Oct 30 2024
We got to see some light pockets of showers through the morning
hours mainly near and west of San Antonio and coastal Plains areas.
As of 230 PM CDT, EWX Doppler radar is showing some light returns
mainly to the east of Interstate 35. Those may not be reaching the
round. Otherwise, partly cloudy to cloudy conditions have remained
for the eastern two-thirds of south central Texas this afternoon
while most of Val Verde County and portions of the southern Edwards
Plateau are enjoying sunny skies. With all of that said,
temperatures are in the low to mid 80s across the Hill Country and
mid 80s to lower 90s along the I-35 corridor and the coastal Plains.
Latest RAP analysis shows a dry-line that extends from northern Texas
to the southwest into the Big Bend area. This feature is forecast to
slowly push to the east for the rest of this afternoon and then push
back to the west while increased moisture pushes from the Gulf of
Mexico into the coastal Plains, I-35 and the Hill Country. Can`t
rule out a few showers and even a thunderstorm mainly across the
Hill Country this evening as instability goes up. Then, we could
have a short break overnight as far as precipitation goes before a
cold front begins to enter the southern Edwards Plateau and Hill
Country by day break on Thursday.
Hires models and HREF guidance are showing the frontal boundary
starting to affect the Hill Country from 4 or 5 am and continuing
through Thursday morning. Even though the better forcing and dynamic
are going to be to the north of the local area, there is a marginal
risk of a few storms to become strong to marginally severe as they
move over parts of Burnet, Llano and Williamson Counties. Main
hazard with these storms could be strong to damaging wind gusts up
to 60 mph. The frontal boundary is likely to slow down and slowly
push into the I-35 corridor late morning or early evening before
stalling.
Slight to chances of showers and thunderstorms are forecast for
areas along and east of Interstate 35 on Thursday afternoon. High
temperatures are going to be cooler than previous days with highs in
the lower 80s across the Hill Country to upper 80s over the coastal
Plains.
The frontal boundary pushes back to the north on Thursday night and
could generate isolated showers and thunderstorms across the coastal
Plains and the Rio Grande. Overnight lows ranging from the lower 60s
over the Hill Country to upper 60s along and east of I-35 and the
coastal Plains.|
&&
.LONG TERM...
(Friday through Wednesday)
Issued at 240 PM CDT Wed Oct 30 2024
All eyes will be focused on the Pacific Northwest as the next storm
system moves into the western CONUS this weekend. This system will
ultimately bring much cooler temperatures and rainfall to the region
as we move into the beginning to middle of next week.
On Friday, the frontal boundary that moved into the region on
Halloween will become stationary/almost diffuse at the gradient
weakens along the boundary. Easterly flow will continue and will
moist low level flow continuing, low to medium chances for showers
and thunderstorms will develop Friday afternoon and continue through
the weekend under a similar flow regime.
By Sunday afternoon, we should see a notable increase in wind speeds
as southerly flow ramps up ahead of what is expected to be our first
decent cold front since the 16th of October. Winds are not expected
to let up much Sunday all the way through Monday ahead of the
arrival of this next cold front. A powerful upper-level low will
slide southward out of Idaho and into the Four Corners by early
Monday. This will set the stage for surface cyclogenesis in the lee
of the Rockies Monday afternoon. That in turn will send a stronger
cold front into our region by late Monday evening, bringing much
cooler temperatures and another shot at rain and storms. We should
have some 40-50 kts of 0-6km bulk shear, along with 500-1000 J/kg
MLCAPE ahead of the frontal boundary Monday evening. Forecast
soundings show decent lift ahead of the boundary, so a few strong to
severe storms could fire up along the front. It will be very
dependent on timing: If the front moves through late afternoon, the
threat for strong/severe storms is greater as daytime heating will
help with instability, but if the front moves through late evening,
the threat appears more conditional. Beyond Tuesday, our attention
turns to the next storm system that will take shape over the western
CONUS for the middle to end of next week.
&&
.AVIATION...
(00Z TAFS)
Issued at 700 PM CDT Wed Oct 30 2024
Winds are decreasing and this will continue for a few more hours.
MVFR ceilings will develop around midnight in the Austin and San
Antonio areas and a few hours later at DRT. Ceilings will drop to IFR
for a few hours in the San Antonio area early Thursday morning. A
cold front will approach the region and bring a chance for showers to
the Austin and San Antonio areas Thursday morning which will drop
visibility to MVFR. VFR conditions will return to all sites by
afternoon. Winds will shift to the northeast to east behind the
front.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 71 85 66 84 / 50 50 10 30
Austin Bergstrom Intl Airport 71 86 66 85 / 40 50 10 30
New Braunfels Muni Airport 72 88 68 85 / 30 40 10 30
Burnet Muni Airport 68 83 63 81 / 70 50 10 30
Del Rio Intl Airport 70 87 68 85 / 10 10 20 30
Georgetown Muni Airport 70 84 65 83 / 70 50 10 30
Hondo Muni Airport 71 87 67 84 / 30 30 10 30
San Marcos Muni Airport 71 86 66 84 / 30 40 10 30
La Grange - Fayette Regional 72 86 68 83 / 20 50 20 40
San Antonio Intl Airport 73 87 70 84 / 30 40 10 30
Stinson Muni Airport 73 88 71 85 / 20 40 20 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...17
Long-Term...MMM
Aviation...05
Area Forecast Discussion
National Weather Service Green Bay WI
1045 PM CDT Wed Oct 30 2024
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- There is potential for heavy rainfall (1 to 2+ inches) and
thunderstorms Thursday morning. Localized urban flooding will
be possible, especially where storm sewer drains are clogged by
fallen leaves.
- Up to an inch of snow accumulation is possible in Vilas County
Thursday evening.
- Strong southwest winds are anticipated Thursday afternoon which
will veer to the northwest on Thursday evening. The strongest
winds are forecast to occur over the Fox Valley and lakeshore
areas, where gusts up to 45 mph are possible. The periods of
gusty winds will produce hazardous boating conditions through
Thursday night.
&&
.DISCUSSION...
Issued at 252 PM CDT Wed Oct 30 2024
Short Term...Tonight and Thursday
The latest RAP analysis and satellite/radar imagery show a strong
cold front draped from La Crosse to Rhinelander early this
afternoon. Unseasonably warm temperatures in the 70s thanks to
brisk southwest winds 30 to 40 mph prevail ahead of the front,
while colder air in the 40s is moving south behind the front.
Showers developed ahead of the front north of a Wisconsin Rapids
to Iron Mountain line by midday and are expanding in coverage. No
thunderstorms have been observed over northern Wisconsin so far,
but mesoanalysis shows 200-400 j/kg of cape have developed ahead
of the boundary. So not unreasonable to expect a few thunderstorms
to develop as we approach peak heating and stronger
frontogenetical forcing arrives from the southwest. As a
strengthening area of low pressure tracks along the front,
precipitation and wind trends are the focus of this forecast.
Precipitation trends: As low pressure tracks across the central
Plains, backing winds aloft which will lead to an increase of
frontogenetical forcing late this afternoon into the evening. As a
result, the convective allowing models continue to indicate
showers and embedded storms becoming more widespread between
22-00z across the region. Elevated instability of 400-600 j/kg
could cause a couple strong storms to develop that could bring
gusty winds to 35 or 40 mph down to the surface, though winds
will be decreasing aloft by that time.
Moderate intensity rainfall will then continue until late
overnight before a break occurs on early Thursday morning. As
deepening low pressure tracks from southwest to northeast across
Wisconsin on Thursday, another round of moderate rainfall will
sweep across the region during the morning. Dry slotting will
push into eastern Wisconsin in the afternoon which will decrease
precipitation chances significantly. However, light precipitation
will continue over parts of central and all of far northern
Wisconsin through the afternoon.
Temperatures will be falling across the region during the
afternoon. As temps fall into the middle 30s, precip will likely
mix with or change over to snow over parts of central to northern
WI. Perhaps a dusting of snow is possible on grassy surfaces over
Vilas county by 7 pm Thursday.
Wind trends: Gusty winds are expected to subside as the pressure
gradient loosens with the frontal passage tonight. Strong winds
are expected to redevelop on Thursday afternoon on the southern
flank of the low track, where low level lapse rates steepen to 8-9
C/km and cold advection will be occurring. Guidance generally
points to winds ramping up rather quickly in the afternoon over
east-central WI, peaking mid to late afternoon before subsiding
in the evening. With a decent isallobaric push of wind, could see
parts of east-central WI, from Winnebago to Manitowoc in
particular, approaching wind advisory gusts of 45 mph for a few
hours. More uncertainty exists further north closer to the surface
low track. With coordination from WFO MKX, will hoist a Wind
Advisory from 18z to 02z.
Long Term...Thursday Night Through Wednesday
Focus of the long-term forecast are lingering impacts (strong winds
and snow potential) from an exiting low pressure system Thursday
evening/night, as well as, the next chance for rain arriving Sunday.
Thursday evening/night...As the strongest forcing associated with a
dynamic low pressure system exits the region and dry mid and upper-
level air infiltrated the region Thursday evening rain will diminish
across central and east-central WI. Cyclonic flow will feed moisture
into northern WI through Thursday night, which along with strong CAA
and low-level temperatures cooling to around freezing will likely
lead to a period of snow across north-central WI. NBM probs show a
greater than 50% for measurable snow north and west of a Tomahawk to
Iron Mountain line Thursday evening. There is around a 50-70% chance
for greater than 1" of snow across northwest Vilas county Thursday
night. However, with relatively warm ground temperatures there is
uncertainty with how much snow may actually accumulate. Don`t
expected any major impacts with this snowfall, but there may be a
few slick spots on northern WI roads during the Friday morning
commute.
Strong winds are also expected to linger through Thursday evening,
particularly across the Fox Valley and east-central WI. A 850mb LLJ
around 40-50kts and strong CAA will make conditions favorable for
wind gusts of 35-45mph to mix down to the surface. There is a low
end ~ 20% chance for a few gusts around 50mph south of highway 10
between Oshkosh and Manitowoc. With these winds out of the west high
profile vehicles may be impacted on north-south oriented roads
including I-41 & I-43. Loose holiday decorations will also be blown
around. As the LLJ moves off to the east and the surface pressure
gradient slacks off winds should trend weaker into Friday morning.
Rest of extended period...A brief period of high pressure should
bring mostly dry conditions for Friday and Saturday. There is a
small chance (less than 15%) for a few showers across far north-
central WI Saturday morning as a weak short-waves moves over Lake
Superior. A more widespread a chance for rain (60-80%) returns
Sunday as southwesterly flow on the backside of a building ridge
over the eastern CONUS ushers in Gulf moisture. NEAFS percentiles
show PWATs climbing near the 99th percentile Sunday and Monday. Weak
elevated instability Monday does point to the potential for a few
thunderstorms across central WI and the Fox Valley.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1044 PM CDT Wed Oct 30 2024
Late this evening a cold front has passed through much of the
region, but had still not passed through KOSH. Mainly IFR
conditions were noted across the region, with some MVFR/VFR in
areas where the front had not passed through or had recently
passed through. Steady showers were noted across most of the
region, save for far north-central Wisconsin.
The cold front will slowly sag south of the rest of east-central
Wisconsin around midnight as flight conditions deteriorate across
the rest of the area. Thunderstorms have mainly ended; however a
few rumbles of thunder will still be possible overnight. Periods
of showers will continue overnight into Thursday morning until a
mid level shortwave brings another round to mainly central and
north-central Wisconsin Thursday afternoon, then taper off
Thursday evening. Some snow may mix in across far north-central
Wisconsin Thursday evening as the precipitation comes to an end.
Ceilings are expected to be IFR/LIFR across the region overnight.
Within the rain and embedded storms, visibilities will likely
fall to MVFR, with periods of IFR visibilities possible.
Conditions may improve to MVFR during the day on Thursday
afternoon across east-central Wisconsin and central and north-
central Wisconsin Thursday evening.
Gusty north or northeast winds are expected behind the front
overnight. As the surface low approaches, further veering of the
surface winds to the south or southwest are expected over central
and east- central Wisconsin on Thursday morning. Strong gusty
winds to 45 kts will be possible over east- central Wisconsin on
Thursday afternoon, easing back below 30 knots Thursday evening.
&&
.MARINE...
Issued at 252 PM CDT Wed Oct 30 2024
No changes to the marine headlines tonight. The sharp wind shift
to the northeast remains in the forecast on the Bay with gusts to
around 20 kts and 2 to 4 ft waves. While this doesn`t technically
reach small craft advisory criteria, conditions are likely to
remain choppy on the Bay, particularly around the time of the wind
shift.
Winds remain on track to crank up as a the dry slot of a
deepening low pressure system moves through Thursday afternoon and
evening. CAA and subsidence will help to mix strong winds aloft
to the surface, leading to possible gale force gusts to 35 to 40
kts. Highest confidence will be for the area south of Sturgeon
Bay. Will upgrade the gale watch to a warning there. Still have
concerns for Door County as well, but guidance fell shy of
criteria so opted for a high end Small Craft Advisory. Potential
for gale force gusts look to hold off until Thursday evening, so
still time for an upgrade in later shifts.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 1 PM to 9 PM CDT Thursday for WIZ048>050.
&&
$$
DISCUSSION.....MPC/GK
AVIATION.......Kurimski
MARINE.........MPC
Area Forecast Discussion
National Weather Service Grand Rapids MI
945 PM EDT Wed Oct 30 2024
.KEY MESSAGES...
- Gusty Winds, Showers, and Storms Tomorrow, Dry but Windy for
Trick-or-Treating
- More Normal Temperatures Then a Warm and Wet Pattern Ahead
&&
.UPDATE...
Issued at 945 PM EDT Wed Oct 30 2024
The Climate section below has been updated to reflect today`s
record highs which where tied at GRR, LAN, BTL, and BIV. Have
also updated the record warm low section for 10/30 as of 9 PM.
It`s possible that BIV and MKG could still slip a degree below
their highest readings for the date before midnight LST but the
other site`s values will probably stand.
Otherwise a pretty quiet (and warm) evening. The primary threat
of showers over the next several hours is mainly just around
Ludington. The rain does not really make better inroads over the
the rest of the area until after about 09Z/5AM and even then the
coverage should be less than what`s currently noted upstream. The
HRRR has been showing some stronger wind gusts over 40 mph
arriving around that time as well as the showers arrive from the
west. Lows tonight in the low to mid 60s.
&&
.DISCUSSION...
Issued at 317 PM EDT Wed Oct 30 2024
- Gusty Winds, Showers, and Storms Tomorrow, Dry but Windy for
Trick-or-Treating
Southwest winds are expected to drop below advisory levels along
the lakeshore this evening, but gusts of 20 to 30 mph are expected
to continue across the area into Thursday. Our next batch of rain
is currently located over the Plains and will shift into the area
after midnight tonight. Positive vorticity advection picks up around
dawn Thursday morning with the 50 knot low level jet feeding into
the area. There will be some instability available around 100-300
J/kg of CAPE, so thunderstorms will be possible. There is a
concern for showers and storms to bring down some of the higher
gusts aloft. Brief gusts of 40 to 50 mph will be possible and may
cause some down branches and power outages. With precipitable
water values around 1.5 to 1.75 inches heavy downpours are also
expected with any thunderstorm.
The dry slot of this system moves in right about when trick-or-
treating starts which is the good news. The bad news is that with
the cooler temperature profile aloft it will still be a bit windy
with gusts to 40 mph possible across much of the area and higher
gusts along the lakeshore. Any witches better hold onto their
brooms tight. Temperatures will also fall Halloween night into the
50s by 8pm and then into the 30s and 40s by Friday morning. This
is also the time where we see moisture wrap back around the low
with northwest winds resulting in some lake effect rain showers
impacting the lakeshore and M-10 corridor.
- More Normal Temperatures Then a Warm and Wet Pattern Ahead
The long term period begins with zonal flow with surface high
pressure with dry and cool weather for the end of the week. The cold
front will have temperatures around normal continuing through the
Saturday. Return flow moisture increases late in the weekend due
to a negatively tilted upper level ridge that will bring warm air
advection along with isentropic ascent. Due to the ridging the
models are in fair agreement so there is good confidence in
increased chances of rain Sunday through Monday.
Rain chances will continue through Tuesday as a deepening upper
level trough moves through the intermountain west and the Great
Plains. As that trough moves over top the ridge next week, the
models solutions vary on timing and placement. However, through this
period there will be a Gulf moisture conveyor belt through the
circulation that will bring persistent moisture allowing for showers
through the Monday and Tuesday timeframe. So overall expect a rainy
period. The warm air advection should bring daytime temperatures
into the 60s early next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 752 PM EDT Wed Oct 30 2024
This will be a highly impactful weather period for aviation
interests.
The initial impacts will be in the form of low level wind shear
starting out by 03-06z from west to east. Another 50 knot wind
core will move in around 2k ft agl. Sfc winds will be quite a bit
less, but still may have some wind gusts 20-25 knots. Thought it
was good to alert pilots of this strong wind core.
The low level wind shear will give way to some showers starting
around 09z, and thunder chances shortly after that. Have included
a Prob30 group to account for that. The showers and thunder will
likely be associated with MVFR at some point. The thunder chances
will end temporarily, with showers persisting, and winds picking
up with gusts 20-30 knots.
Another line of showers and embedded thunder will move in for 2-4
hours mid-late afternoon immediately ahead of the strong surge of
colder air coming in. Winds will increase behind this line from
the SW with gusts to 40 knots likely. This will last through most
of the rest of this forecast period with MVFR clouds.
&&
.MARINE...
Issued at 317 PM EDT Wed Oct 30 2024
Southwest winds will fall below gales this evening and pick back
up Thursday after daybreak. Stronger winds will also be possible
with showers and thunderstorms that move in overnight into
Thursday morning. Gales will continue Thursday until the front
moves through Thursday night. Northwest winds behind the front
gradually become lighter dropping below small craft levels by
Friday afternoon. Waves however will linger, especially over the
southern zones through the late afternoon. Quieter conditions are
expected over the weekend, but winds and waves pick back up next
week as we move into an active pattern of wet weather.
&&
.CLIMATE...
Issued at 945 PM EDT Wed Oct 30 2024
- October 29 NEW Record Highs Set:
Grand Rapids...79... Old 77 (1901)
Lansing........77... Old 76 (1999)
Muskegon.......76... Old 74 (1896)
Holland........79... Old 76 (1922, 1999)
Kalamazoo......80... Old 77 (1999)
Battle Creek...79... Old 77 (1999)
- October 30 NEW Record Warm Lows (as of 9 PM):
Grand Rapids...65... Old 58 (1901, 1974)
Lansing........64... Old 59 (1974)
Muskegon.......67... Old 59 (1901)
Holland........70... Old 57 (1946, 1999)
Kalamazoo......66... Old 63 (1946)
Battle Creek...64... Old 59 (1900)
- October 30 TIED Record Highs:
Grand Rapids...79 (1950)
Lansing........77 (1950, 1971)
Battle Creek...78 (1950)
Holland........77 (1948, 1971)
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Gale Warning until 2 AM EDT Friday for LMZ844>849.
&&
$$
UPDATE...Meade
DISCUSSION...Ceru/RAH
AVIATION...NJJ
MARINE...RAH
CLIMATE...CAS
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
638 PM CDT Wed Oct 30 2024
.KEY MESSAGES...
- A QLCS will move across the area late tonight through early
Thursday morning with an accompanying potential of strong to
damaging winds and a low chance of isolated tornadoes.
- Cooler/drier air and tranquil weather will dominate Thursday
afternoon through Friday night.
- A more active and wet weather pattern will evolve this weekend
and persist into the first half of next week. Multiple waves of
rain will impact parts of the area bring beneficial rainfall to
help ease the ongoing drought conditions.
&&
.SHORT TERM... (Through Late Thursday Night)
Issued at 152 PM CDT Wed Oct 30 2024
The main issue tonight into early Thursday morning remains the
severe weather threat across the region. All of the available
guidance and CAMs continue to show a QLCS evolving across eastern
KS and western MO this evening with the QLCS moving eastward
through the CWA overnight and into early Thursday morning. There
are some slight differences in timing/speed of the QLCS. The
typically better performing CAMS like the HRRR, ARW, as well as
the MPAS-HT show the QLCS moving into central and northeast MO
between 05-06z, through the St. Louis area around 09-10z with a
position across far SE MO and SW IL around 12z. This type of event
would be characterized as a HSLC event. ALthough the overall
trends show slowly diminishing instability as the QLCS progresses
eastward through the CWA, the latest RAP suggests the diminishment
may be both slower and not occur until the system is farther
east. The RAP maintains an axis of MLCAPE of 500-800 J/KG through
09z or so, and at least 500 J/KG or so through 10-11z, with a more
rapid decrease thereafter as the system moves through SW IL and
SE MO. Both the 0-3 km shear on the order of 35-45 kts ahead of
the QLCS and line-parallel 0-1 km shear equal in magnitude support
QLCS mesovortices, particularly with local bowing segments and
surges to the east-northeast. Certainly the threat of damaging
winds and isolated tornadoes is greatest through central MO and
into portions of eastern MO owing to the greater instability, but
the risk of damaging winds and isolated tornadoes will continue
into SW IL with any local surges provided the system does not
become outflow dominant. The current expectation is that
precipitation should exit the entire area by mid-late Thursday
morning with much cooler temperatures, stratus/stratocu, and gusty
west winds in the wake of the attendant cold frontal passage.
Thursday night/Halloween looks nice with surface high pressure
settling into the area, clearing skies, and seasonably cool
temperatures.
Glass
&&
.LONG TERM... (Friday through Next Wednesday)
Issued at 152 PM CDT Wed Oct 30 2024
The long range period starting on Friday will begin on a tranquil
note with heights rising aloft as short-wave ridging builds
across the area and slowly retreating surface high pressure
dominates. Temperatures will be near normal with high clouds
slowly increasing.
The latest guidance continues to support a wet and active period
centered on Saturday through the first half of next week. A
deepening longwave trof over the western U.S. will result in mid-
upper level southwest flow across the region which really becomes
established Saturday-Saturday night and strengthens heading into
Tuesday. From Saturday through Monday the ensemble guidance suite
is in relatively good agreement with this large scale pattern
which favors a series of low-amplitude short-waves traversing the
region within the southwest flow. These waves combined with a
rather persistent southwesterly LLJ and eventually a frontal
boundary wavering northward support multiple waves of showers and
periodic thunderstorms.
While the overall pattern is supportive of this regime, the
deterministic guidance in this time frame does show typical
differences in the timing/location of waves of rain owing to
short-wave positioning. The most-prevalent of these differences is
on Saturday when the operational GFS and some of the GEFS
membership is a bit more progressive with short-wave ridging
sliding to the east, thus is faster with a lead short-wave and
greater precipitation chances. Otherwise there is fairly good
agreement that from Saturday night onward. Present indications
are that the main upper low/short-wave trof will lift
northeastward from southern Rockies into the upper MS Valley
Monday into early Tuesday and this should at least bring an
advancing cold front into or possibly through the region. Tuesday
into Wednesday the LREF is showing increasing divergence in the
large scale pattern and position of the longwave trof. There are 4
distinct clusters of the ensemble membership with the eastern-
most showing the upper trof axis centered through the Plains
region while the western-most has the trof axis further west
through the Four-Corners region. The ramifications of these
differences are timing of the Tuesday cold fropa and longevity of
rainfall chances into Wednesday.
This pattern will bring the region much needed rainfall, especially
where drought conditions are the worse. The probabilities of
significant amounts are much higher across northeast and central MO
closer to the main short-wave track and LLJ axis with exceedance
guidance from the 100 member LREF indicating nearly 100 percent
chance of total rainfall over 1 inch and a 50-70 percent chance
of 3+ inches. The probabilities taper to the east with the lowest
probabilities across SE MO and far SW IL; 75-90 percent of total
rainfall over 1 inch and 20-30 percent chance of 3+ inches.
Temperatures should be above normal during the Saturday-Wednesday
period with the NBM probabilistic guidance indicating the
greatest potential for well-above normal (10-15+ degs) Sunday-
Tuesday.
Glass
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 638 PM CDT Wed Oct 30 2024
Dry and VFR flight conditions along with strong south-southeasterly
winds will persist this evening ahead of a line of thunderstorms
developing across eastern KS and northwestern MO. These
thunderstorms are forecast to track northeastward through the entire
area overnight into early Thursday morning. These thunderstorms
could be severe, accompanied by a short period of gusty to damaging
winds and IFR flight conditions. Rain and a few rumbles of thunder
will linger for another couple of hours while winds veer to westerly
with passage of a cold front and post-frontal MVFR
stratus/stratocumulus arrive. Improvement in flight conditions is
expected around midday/early afternoon as ceilings lift and scatter
accompanied by gusty westerly winds. Gusts will subside Thursday
evening.
Pfahler
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
717 PM EDT Wed Oct 30 2024
.KEY MESSAGES...
- A much needed 1 to 2 inches of rain is expected through Thursday
night between the departed cold front and a low pressure system that
lifts northeast over the area on Thursday.
- Rain changes over to wet snow Thursday afternoon especially in the
highlands of western Upper Michigan. Snow totals will vary by
elevation, with shorelines and much of the lower-lying areas seeing
an inch or less of snow but the high terrain of Marquette/Baraga
County and the Copper Country are 50% likely see near 4 inches of
snow by Friday morning.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 327 PM EDT Wed Oct 30 2024
Water vapor imagery and RAP analysis show an amplified split flow
pattern across N America. A southern stream mid-level trof is over
the Rockies with ridging over the eastern states. To the n, a fairly
deep trof is centered over Hudson Bay in the northern stream. The
flow emanating from the Rockies trof enters a confluence btwn the
eastern ridge and the Hudson Bay trof over northern Ontario,
resulting in upper jet streak reaching 130kt as the flow approaches
James Bay. Upper diffluence in the right entrance of the upper jet
along, 500j/kg or so of MUCAPE, and sharp cold front advancing
across the area have resulted in streaks of ne moving shra/tsra
across the fcst area today, some producing gusty winds of 40+kt,
mainly over Lake Superior. Ahead of the front, it`s been another
unseasonably warm day with temps as high as the mid and upper 70s F
across portions of central Upper MI. Temps fall sharply behind the
front. Current readings are only in the 40s F across much of western
Upper MI.
Cold front will settle s tonight, but will hang up roughly from
central WI ene across the vcnty of the Straits due to a low pres
wave developing over IA. As upper jet reorients, models show upper
diffluence strengthening across Upper MI with low to mid-level fgen
responding. So, shra should tend to organize and consolidate to the
n of the cold front tonight, affecting roughly the se 2/3rds of the
fcst area. Some thunder remains possible, mainly s central and e,
but that potential diminishes as axis of MUCAPE diminishes and slips
s and e thru the night. Any thunder should be confined to the
evening hrs. To the w and nw, areas from around Ironwood thru the
Keweenaw will dry out with most of tonight being rain free. By
sunrise, temps should range from around 40F w to the upper 40s s
central and e.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 420 PM EDT Wed Oct 30 2024
An active pattern is ahead for the Upper Great Lakes under a highly
amplified 500mb pattern. The primary features of note will be a
negatively tilted trough over the Central Plains that will pass over
the UP Thursday, persistent ridging over the eastern CONUS that will
only be temporarily interrupted by the prior trough, and broad
troughing over the western CONUS that will bring the potential for
active weather into next week depending on how that trough advances
northeast out of the Four Corners region. While spread is still high
on the impacts from next week`s weather, in the meantime, widespread
rainfall, gusty winds, and some snow accumulation potential will
define the impactful weather through the end of this week.
Ahead of the trough on Thursday, surface low pressure of around
1000mb is expected over the La Crosse, WI area at 12Z Thursday per
the 12Z GEFS. Ensembles are in good agreement about the track and
intensity of this low as it passes through Wisconsin towards the
Straits of Mackinac by 00Z Friday. Widespread showers are expected
with this system, with the 12Z HREF mean showing an additional 0.5-
1.5 inches of rain from 12Z Thursday to 12Z Friday on top of the
rainfall from Wednesday and Wednesday night. With the HREF showing
the highest precip totals over the high terrain of Marquette,
Baraga, Gogebic, and Ontonagon counties, this will be a great relief
to the fire weather conditions that have plagued especially the
Summit Lake wildfire area. Significant cold advection is expected
behind the low pressure and by 17Z Thursday, the HREF shows over 50%
chances of hourly accumulating snowfall rates in the Ironwood
vicinity and expanding to the east. The NBM has come in a bit higher
than the HREF as far as snow totals go, with the NBM not cooling the
boundary layer nearly as quickly as the HREF, though the NBM does
have lower than 10:1 SLRs, accounting for warm ground conditions
(soil temperatures still in the mid-50s and paved surfaces likely
warmer). Nevertheless, strong lift is expected in the DGZ, so 6-
hourly snowfall rates in excess of 2 inches/6 hours in the west half
high terrain Thursday afternoon/evening is expected (50%+). Overall,
expecting total snow accumulations to be less than an inch
widespread, but the Copper Country and Baraga/Marquette highlands
could see 2-4 inches with the Mt. Arvon area up to 50% likely to see
4-6 inches of snow. Given the highly localized nature of the
snowfall, will elect not to go with any winter weather products at
this time and allow later shifts to track trends in the hi-res
models. Compressed pressure gradient ahead of the low will also
allow for some gusty winds of 25-35 mph Thursday, and while any snow
will probably be too wet for blowing snow, a few isolated pockets of
blowing snow may reduce visibility in high terrain Thursday night.
Behind the low pressure, 850mb temperatures cool to near -8 C. With
lake temperatures around 10C, a brief period of lake enhanced to
lake effect snow is expected Thursday night into Friday, though with
ridging building in quickly behind, hi-res data suggests only light
accumulations for the east half of a half inch or less and
showers ending quickly Friday morning. Ridging aloft will keep
Friday dry and cool with NBM 50th percentile highs only in the
low to mid 40s. A weakening shortwave will pass north of Lake
Superior Friday night into Saturday night, bringing a slight
chance (~25% chance or less) of some light rain showers along
Lake Superior on Saturday, but most should stay dry. The weekend
will warm up into the 50s with anomalous ridging building to
+17 dam at 500mb by Sunday evening. From here, the ensembles
diverge enough that exact details become uncertain, but the
general expected pattern for next week is for digging troughing
over the Four Corners region to eject northeast towards the
Midwest, and whatever surface low(s) that emerge from that
and/or any northern-branch clipper lows will bring active
weather and precipitation to the UP next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 711 PM EDT Wed Oct 30 2024
Showers will consolidate across central and eastern Upper MI
tonight before expanding further on Thu as low pres lifts toward
Upper MI. At IWD, expect LIFR to improve to IFR later this
evening as drier air filters in from the north. prevail this
aftn under upslope northerly winds. A few shra are also
possible. At CMX, somewhat drier air will filter s, allowing
improvement from IFR to MVFR this evening. A return to IFR
expected near the end of the fcst period as heavier rain
arrives. At SAW, expect IFR to prevail thru the end of the fcst
period. LIFR may set in near the end of the fcst period. More
frequent showers will settle in at SAW in the next couple of
hours with heavier rain expected later Thu morning. Gusty n to
ne winds to 20-30kt are expected on Thu at all terminals as the
low pres approaches.
&&
.MARINE...
Issued at 420 PM EDT Wed Oct 30 2024
Behind the cold front today, wind gusts out of the north at 20-25 kt
are ongoing and will persist into tonight. A low pressure system
will pass south of the UP Thursday, and the compressed gradient will
result in gradually building northeast winds overnight eventually
becoming gales to 35 knots first in the west half of the lake
Thursday morning and then in the west by early afternoon. As winds
become more northerly and eventually northwesterly, the winds over
the east half are likely (50+%) to exceed 40 kt especially near
Stannard Rock. Ridging quickly builds in behind the low, resulting
in winds falling below 20 kt for the west half by early Friday
morning just as gales end in the east, and winds will be below 20 kt
lakewide by Friday afternoon. The weekend will be fairly quiet under
ridging aloft, but next week, another low pressure system is
expected to bring gusty winds and rough seas to Lake Superior,
though there are significant differences between models on the
track, intensity, and timing of the low at this time. Wave
heights are expected to be 4-7 feet across much of the lake
tonight, building to 8-12 feet tomorrow with the highest waves
near 15 feet bounded to the west by Big Bay, to the east by
Grand Island, and to the north by Stannard Rock. Waves fall
below 4 feet by Friday evening.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning from 8 AM EDT /7 AM CDT/ to 4 PM EDT /3 PM CDT/
Thursday for LSZ162.
Gale Warning from 8 AM EDT /7 AM CDT/ to 11 PM EDT /10 PM CDT/
Thursday for LSZ240>242-263.
Gale Warning from 2 PM Thursday to 2 AM EDT Friday for LSZ243-
244-264.
Gale Warning from 2 PM Thursday to 5 AM EDT Friday for LSZ245-
248-249-265-266.
Gale Warning from 8 PM Thursday to 5 AM EDT Friday for LSZ250-
251-267.
Lake Michigan...
Gale Warning from 11 PM Thursday to 5 AM EDT Friday for LMZ221-
248-250.
&&
$$
SHORT TERM...Rolfson
LONG TERM...GS
AVIATION...Voss
MARINE...GS
Area Forecast Discussion...UPDATED
National Weather Service Reno NV
741 PM PDT Wed Oct 30 2024
.UPDATE...
Smoke has worked into the Carson Valley based on observations
including air quality sensors which have increased into the
moderate to unhealthy range from South Lake Tahoe to Minden. We
have updated to push the smoke farther north for the evening.
Meanwhile, winds have increased a bit earlier on Lake Tahoe and
were sustained around 20 mph with gusts near or exceeding 30 mph.
So we moved the start time of the lake wind advisory up. Products
and gridded database have been updated.
Hohmann
&&
.PREVIOUS DISCUSSION... /issued 444 PM PDT Wed Oct 30 2024/
UPDATE...
Smoke from a prescribed burn on the west slopes of the Sierra east
of Big Trees has drifted into the Tahoe area and was producing
reduced visibility - and according to the latest air quality
sensors in the region, bringing moderate air quality to South Lake
Tahoe. Latest HRRR simulations show the smoke dispersing this
evening as breezy south winds ahead of our frontal system keep
things mixed up. We have updated our gridded and KTVL aviation
forecasts to reflect these trends with a few hours of MVFR flight
restrictions into early evening.
Hohmann
PREVIOUS DISCUSSION... /issued 1250 PM PDT Wed Oct 30 2024/
SYNOPSIS...
* A wintry weather system brings mountain snow and valley rain
this evening and into Thursday morning.
* A second system is expected to bring more mountain snow and
valley rain chances Friday and Saturday.
* Following lingering precipitation chances Sunday, dry conditions
prevail by Sunday night and into the work week.
DISCUSSION...
Overnight lows this morning dropped to below freezing for much of
the area. Those cool temperatures will prevail through this week
with two storm systems impacting much of the area by Sunday. Despite
some drying out today, that will quickly change late tonight.
The upper fringes of Washoe county will get the first taste of this
storm system late tonight with snow reaching Donner Pass and west I-
80 around midnight. Snow accumulations may reach as high as 5 inches
for mountain passes. However, this system seems quick and more
contained; there won`t be much spillover into the valleys. The snow
levels will be around 5500 feet, resulting in valley rain Thursday
morning. Roads, especially along mountain passes, will be slick
during your morning commute. This system will also bring gusty winds
to the Tahoe area and Mono county. The Tahoe area will see gusts
exceeding 50 mph when the system moves through while peaks in Mono
county will see gusts of over 70 mph until around noon.
Friday evening, our next system moves into the area. This system
will be colder and wetter, resulting in more snow. However, just how
much is uncertain. Areas of the Sierra could see anywhere from 6
inches to 2 feet. In addition, this system could bring accumulating
snow down to Mammoth. As we get closer to Friday, please stay tuned
to see how some of those values shake out. Models are currently
showing some spillover Saturday with snow levels falling to near
valley floors. Expect valley rain unless those snow levels drop
enough. Virginia City may also see some snow with this system with
a 30% chance of greater than 1 inch of snow. While there is
uncertainty in the extent of the snow, we are expecting widespread
impacts to travel Friday night and through Saturday. It`s
possible that this storm will bring the beginning of widespread
chain restrictions in higher passes. Please heed all travel
restrictions.
Sunday and into early next week, we start to dry out as some ridging
builds back into the area. However, this looks to be short lived;
some models have a slider-type system impacting the area as early as
Tuesday night. Stay tuned for more details as we get closer to next
week. -Giralte
AVIATION...
VFR conditions expected for the rest of today before a winter storm
system drops into our area late tonight, bringing snow and valley
rain. KRNO, KCXP, and KMEV will see periods of lower visibilities
(MVFR conditions), light rain, and mist late tonight. KTRK and KTVL
will instead see snow, dropping to IFR conditions between 31/07Z and
31/12Z. There`s a ~50% chance of snow sticking to runways for both
mountain sites.
Wind gusts today reach up to 20 kts, locally higher up to 30 kts for
mountain TAF sites. Periods of LLWS are forecasted for all TAF sites
tonight, starting around 31/02Z and prevailing until 31/12Z.
-Giralte
&&
.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory until 11 AM PDT Thursday NVZ002.
CA...Winter Weather Advisory from 11 PM this evening to 2 PM PDT
Thursday CAZ071-072.
Lake Wind Advisory until 11 AM PDT Thursday CAZ072.
&&
$$