Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/16/22
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
918 PM CDT Sat Oct 15 2022
.UPDATE...
Issued at 917 PM CDT Sat Oct 15 2022
No major changes are needed for this update. Current conditions
and trends were blended into the forecast. The large area of
stratus clouds continues to erode from northwest to southeast
this evening.
UPDATE Issued at 640 PM CDT Sat Oct 15 2022
A large area of stratus continues to blanket much of the forecast
area early this evening. RAP RH fields appear to be handling the
clouds well, and suggest gradual clearing from northwest to
southeast through the evening, which can already be seen in the
northwest corner of the state. There was a brief period of
drizzle at Beach during the late afternoon, but that appears to
have subsided.
&&
.SHORT TERM...(This Evening through Sunday)
Issued at 116 PM CDT Sat Oct 15 2022
A western U.S. upper ridge and an eastern U.S. trough will
maintain a northwest flow through the short term period.
A cold front has moved through the forecast area. Expect northwest
winds generally 15 to 30 mph this afternoon. Clouds have developed
over a good portion of the western and northern forecast area.
Expect increasing cloudiness over the south central into the James
River Valley late this afternoon into this evening.
Winds will diminish this evening but may remain a little breezy
over central ND. Look for overnight lows mostly in the 20s. Mostly
cloudy conditions early tonight will give way to clearing skies
from northwest to southeast through the night.
Cold high pressure traverses the forecast area on Sunday. Highs
will be colder than today, mainly in the 40s, with some upper 30s
possible around the Turtle Mountains. Winds will be lighter
though on Sunday with the surface high overhead. We remain in a
northwest upper flow and although we expect a good amount of
sunshine early in the day. We do expect increasing mid and high
level cloudiness through the day, especially west.
.LONG TERM...(Sunday Night through Saturday)
Issued at 116 PM CDT Sat Oct 15 2022
Dry conditions and a warming trend highlight the extended forecast
period.
The western U.S. ridge and eastern U.S. trough pattern to begin
the long term period Sunday night and Monday, slowly transitions
to a broad quasi-zonal flow along the International Border by
Friday with a western trough starting to develop next weekend.
This is supported in both the deterministic and ensemble solutions
although the deterministic solutions are a bit slower and deeper
with the western trough development next weekend. However, until
we get there we are looking at mostly dry conditions.
With a northwest flow pattern and especially early in the period,
a passing sprinkle or shower can`t be ruled out, but most will
remain dry through Saturday. Perhaps we could see some small
precipitation chances entering into the forecast Saturday night,
as a western trough develops east into the Plains States by later
in the weekend. Currently, our NBM guidance has introduced some
slight chance pops Saturday night, but remains completely dry
until then.
Expect a wide range of temperatures early in the work week with
temperatures ranging from 15 to 20 degrees between the cooler
Turtle Mountains to the James River Valley, and the warmer
temperatures over western North Dakota. By mid to late in the work
week, all will enjoy the warmer temperatures as broad upper level
ridging covers the region. Widespread upper 50s and 60s are
expected Wednesday through Saturday, with some 70 degree readings
possible southwest and south central. At this time we accepted the
NBM temperatures through the extended period, but if this trend
remains, would not be surprised if we are blending in some warmer
guidance temperatures with the NBM mid to late next week. We may
see a few breezy afternoons with low daytime humidities, but at
this time there doesn`t appear to be any real windy days in the
extended period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 917 PM CDT Sat Oct 15 2022
VFR ceilings around 3,000-5,000 ft will continue to erode from
northwest to southeast late this evening into the night. VFR
conditions are now expected at all terminals through the forecast
period. Northwest winds will sustain around 10 kts overnight,
increasing slightly Sunday afternoon.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Hollan
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...Hollan
Area Forecast Discussion
National Weather Service Cheyenne WY
510 PM MDT Sat Oct 15 2022
.SHORT TERM...(Late this afternoon through Monday night)
Issued at 230 PM MDT Sat Oct 15 2022
The CWA remained wedged between a deep expansive upper trough over
the eastern CONUS and high amplitude upper ridge to the west. Cyclonic
north-northwest flow aloft prevailed, with a few embedded shortwaves
rotating on the backside of the trough. One wave was moving through
northern and eastern WY, producing widely scattered showers. Some of
these showers will affect areas from Douglas to Wheatland to Alliance
northward through late this afternoon. Otherwise, mostly cloudy skies
prevailed with temperatures in the mid 50s to mid 60s.
The cool dry northerly flow aloft will continue through Sunday night.
Expect mostly clear skies tonight through Sunday night. Most frost
coverage overnight will be confined along and west of the Laramie
Range. The 700mb temperatures Sunday will range from -2C to 2C,
yielding afternoon highs in the mid 50s to around 60F. Northwest
winds will be breezy at times over the high plains Sunday afternoon.
More widespread freezing temperatures are forecast east of the Laramie
Range Sunday night with minima from 26F to 32F. Most of these zones
have already experienced freezing temperatures. Frost coverage will
be more widespread along and east of Interstate 25.
A warming trend commences Monday as the upper ridge to the west shifts
east toward the CWA. 700mb temperatures will moderate to 2C to 6C in
afternoon, yielding highs in the low to mid 60s. Subfreezing
temperatures are forecast once again Monday night east of Interstate
25.
.LONG TERM...(Tuesday through Saturday)
Issued at 230 PM MDT Sat Oct 15 2022
Quiet weather expected for the work week as a somewhat anomalous 500
mb high pressure center sits over eastern Idaho/western Wyoming through
mid-week. This will result in dry conditions with above average high
temperatures through at least Friday. Low to mid 60s are expected for
areas west of the Laramie Range. Areas to the east will see temperatures
in the mid 60s to low 70s, which is about 5 to 10 degrees above average.
Next precipitation chance looks to be Saturday night as both the GFS
and ECMWF are in pretty good agreement of a stark cold front dropping
down from the northwest during that time. Lower elevations will likely
miss out on the better precipitation as both models peg the mountains
with pretty good QPF. If these solutions hold true throughout the week,
the Snowy and Sierra Madre Ranges could see a few inches of accumulating
snow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 503 PM MDT Sat Oct 15 2022
Some concern for IFR stratus to develop around KLAR overnight.
HRRR guidance suggesting this as well as the latest SREF guidance.
Would not happen until early morning around 12Z. For now...went
with scattered low clouds and will reevaluate for the 06Z TAFs.
Confidence would need to be a little higher before adding to their
TAF. VFR elsewhere.
&&
.FIRE WEATHER...
Issued at 230 PM MDT Sat Oct 15 2022
A cold front will continue to sag south into northern Colorado late
this afternoon. A trailing weak upper level disturbance will produce
a few showers this afternoon over east central Wyoming and northern
Nebraska Panhandle. Near to slightly below average temperatures will
prevail this weekend, followed by slowly warming temperatures next
week. Minimum humidities will be above 30 percent this weekend,
decreasing to the mid teens percent Wednesday through Friday when
elevated to near critical fire conditions develop as winds increase.
The next chance for measurable precipitation will not be until late
next weekend.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MAJ
LONG TERM...LK
AVIATION...GCC
FIRE WEATHER...MAJ
Area Forecast Discussion
National Weather Service Gray ME
1118 PM EDT Sat Oct 15 2022
.SYNOPSIS...
Mostly dry weather is expected through the rest of the weekend
with frontal boundaries pushing east of the area and high
pressure moving overhead Sunday. A frontal system approaches
from the Great Lakes late Sunday night and Monday bringing a
soaking rain into Tuesday. Cooler and dry weather is expected
behind this system through the end of next week.
&&
.NEAR TERM /TONIGHT/...
1115 PM Update... Another round of tweaks to the forecast,
mainly to account for observed trends in fog... and the status
of the stratus tonight. Stratus has expanded in coverage over
much of western Maine, turning more patchy up toward the western
Maine mountains. Am expecting this to remain in place but
gradually erode as a weak cold front pushes in from the coast...
remaining most stubborn near the coast, where lowered
visibility is also occurring. Don`t foresee widespread dense fog
issues with this... but abundant low-level moisture may produce
some as the night goes on.
637 PM Update... Little change to the forecast for the majority
of the area... I did however have to modify sky grids a bit due
to a marine stratus deck that has formed along the Midcoast...
pushing through the northern reaches of Casco Bay and all the
way across to Penobscot Bay. Some models are hinting that this
stratus descends into a dense fog bank... will have to keep a
close eye on this in case a dense fog advisory is needed through
the morning hours.
Previously...
A highly amplified 500 mb pattern remains in place across North
America through the rest of the weekend with a deep trough over
Hudson Bay extending southward through the Ohio Valley. This
trough will make little if any progress eastward over the next
36 to 48 hours. A north to south stationary boundary across
central and eastern Maine has led to isolated showers to moving
ashore along the Mid Coast into the Capital District with latest
hi res guidance suggesting these will dissipate prior to
sunset. Otherwise, the trough will remain far enough to the west
of the area limiting precipitation chances through the rest of
the weekend.
Latest satellite imagery shows marine stratus/fog along and offshore
of the Mid Coast with the latest HREF suggesting this will bring
patchy fog to the Mid Coast and portions of interior central Maine
tonight. How far inland and the western extent of this fog potential
remains somewhat in question as the NamNest brings reduced
visibility from fog all the way to the foothills back to the ME/NH
border while the HRRR shows little inland penetration of fog. Have
tried to find the middle ground between these solutions for fog
tonight as well as putting some patchy fog in the CT Valley late
tonight. Otherwise, skies will be partly to mostly clear with lows
in the 30s north to 40s south.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A dry cold front will approach from the west late tonight and
crosses the area Sunday morning. Not expecting much in the way
of precipitation with this front with the main sensible weather
impact being a slight drop in dewpoints and high temperatures
running a few degrees lower than today. After any morning fog,
skies will turn mostly sunny through late morning before turning
partly sunny in the afternoon. Highs will range from the mid
50s north to mid 60s south.
Despite the lowering of dewpoints from the cold frontal passage,
onshore flow will again bring the threat of marine stratus and
patchy fog along the coastal plain of Maine into southeast NH Sunday
night. Clouds will start to increase late in the night as low
pressure starts to take shape over the Great Lakes with a warm front
extending into southern New England. There will also be potential
for fog within sheltered interior valleys such as the CT Valley.
Lows Sunday night will range from the 30s north to mid 40s
south.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Overview: Trofing prevails in the extended thru the work week. The
slow progression of the pattern will lead to a gradual step down in
temps. The best chance for precip will be early in the week.
Impacts: The main concern will be QPF as the last event has left
rivers running high and soil saturated. While the heaviest QPF looks
to be east of the forecast area...a shift westward would be cause
for concern that rivers make another run above action
stage...especially for western ME. Late in the week will also
feature colder overnight temps...and frost/freeze conditions are
possible just before the season comes to an end.
Forecast Details: Weather will be more active to start the period
than ending it. Trof axis will remain over the Great Lakes and leave
the Northeast in the WAA portion of the flow. A series of S/WV trofs
will pass thru the flow and lead to what looks like two rounds of
higher PoP. One on Mon look more warm frontal in nature and showery.
The follow up wave is currently modeled to be the stronger of the
two with a more robust connection to deep moisture. EFI and ensemble
guidance suggest the highest QPF threat is east of the forecast area
and despite the time range of the event there is good agreement
between suites. Generally looking at mean QPF less than an inch
across most of the forecast area...save for parts of the Kennebec
River Valley and Penobscot Bay region. After Tue there may be
showers...mainly in the mtns...but little QPF on consequence.
Temps will be a secondary focus as much colder air dumps into the
CONUS. At this time the colder air looks to maximize west and then
south of the forecast area...as we remain largely in the southwest
flow portion of the upper trof. While colder air will eventually
make it here by late in the week...it will be more modified by then.
It will introduce a couple nights of widespread 30s however...and
with the frost/freeze program still active thru the 21st there may
be some need for headlines.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Short Term...Patchy fog in the CT Valley will bring the threat
of IFR to LIFR conditions at KLEB for a few hours prior to and
through sunrise. Will also need to monitor marine stratus/fog
just offshore the Mid Coast that will bring the threat of
IFR/LIFR conditions to KRKD and KAUG, although confidence is not
high enough to put in the TAF. Otherwise, VFR is expected to
prevail tonight through Sunday. Will again need to monitor
potential for marine stratus and fog Sunday night as well as
radiation fog within interior valleys Sunday night for
potential flight restrictions at most terminals.
Long Term...Expecting conditions to deteriorate Mon as initial wave of
precip approaches. Low clouds in addition to the SHRA will bring
periods of IFR conditions thru Tue...especially across western ME.
As southerly flow aloft increases Tue there may also be a period of
LLWS for ME terminals. VFR conditions will return Wed and without a
significant period of high pressure it will be difficult to pin
down any potential impacts from valley fog despite recent wet
weather.
&&
.MARINE...
Short Term...Latest buoy observations show seas 5 to 7 feet
outside of the bays, with guidance keeping seas to at least 5
ft through 09Z. Have extended the SCA for seas to 5 ft through
09Z with winds and seas then remaining below SCA thresholds
through Sunday night.
Long Term...It is getting to be that time of year when SCA conditions
become more likely than not. Starting Mon thru the end of the week
looks like a period of SCA to near-SCA conditions. While at this
time winds/gusts do not appear overly strong...the persistent flow
direction may keep seas near 5 ft outside of the bays into Thu/Fri.
There may also be areas of fog that develop on the waters ahead of
the precip early in the week...but confidence is too low to include
in the forecast at this time.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 5 AM EDT Sunday for ANZ150-152-154.
&&
$$
UPDATE...Casey
NEAR/SHORT TERM...Schroeter
LONG TERM...Legro
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
910 PM CDT Sat Oct 15 2022
.UPDATE...
Issued at 910 PM CDT Sat Oct 15 2022
Current forecast remains in good shape for this evening with no
major changes made.
A quiet and fall-like evening is underway across northeastern
Illinois and northwest Indiana with current temperatures sitting
in the upper 40s to around 50 degrees. An area of mid-level clouds
continues to reside across the area, but the clouds are gradually
pushing eastward as a weak frontal boundary continues to move
southward across Wisconsin. While this boundary will not bring any
precipitation it will allow the cloud cover to persist through
much of the overnight hours before skies gradually clear out
Sunday morning. The presence of these clouds will help to keep
temperatures a tad warmer tonight than last night with lows
expected to be in the mid to upper 30s for most of the area with
lower 40s for the Chicago metro.
Sunday will see similar conditions to what we saw today with
mostly sunny skies to start the day becoming partly cloudy by
dinner time as an upper-level disturbance moves into the area. Temperatures
will once again top out in the mid to upper 50s with breezy
northwest winds gusting around 20 to 25 mph during the afternoon.
As the aforementioned disturbance moves in guidance is continuing
to indicate that a few spotty sprinkles may develop across
northern Illinois late Sunday afternoon. However, the shallow
moisture forecast to be in place should keep most areas dry.
Yack
&&
.SHORT TERM...
Issued at 235 PM CDT Sat Oct 15 2022
Through Sunday...
A surface high to our west will slip to our south and southeast
today, with mostly clear skies and westerly winds becoming
southwesterly. Winds will be gusty this afternoon, with gusts up to
25 mph. Cloud cover associated with an approaching front will
increase later this afternoon into the evening, but will move off to
the east after midnight. No precipitation is expected from this
overnight front. Winds will remain a bit gusty this evening, with
gusts up to 20 mph possible, but decreasing after midnight. 850 MB
temperatures, which started out below 0 C, will climb to around 5 C
tonight, which is still below the normal 8 C. This slight increase
and slight southerly flow will lead to lows several degrees warmer
Sunday morning, ranging from the mid 30s to the north, to around 40
to the south and across Chicago. Temperatures to the north will
still be cold enough to create some spotty frost along and north of
I-88, and away from Chicago, early Sunday morning.
Sunday morning will start with mostly clear skies, but clouds will
increase once again midday as a stratocumulus deck develops from a
reinforcing shot of cold air Sunday afternoon. Temperatures between
900 and 800 MB will drop below freezing, with a bit of elevated CAPE
within the cloud deck, which may lead to a chance for some isolated
showers Sunday afternoon, mainly in northeast Illinois. Winds will
increase again Sunday afternoon with gusts of 25 to 30 mph. Cold air
advection (CAA) at the surface will not start until the later
afternoon/early evening, with Sunday high temperatures in the 50s.
BKL
&&
.LONG TERM...
Issued at 235 PM CDT Sat Oct 15 2022
Sunday night through Saturday...
Key messages in the extended forecast period:
1. Blustery conditions expected MON-TUE (Highs in 40s)
- Near record cold highs MON - *see climate section below
- NNW wind gusts up to 35 mph and sub-freezing wind chills
2. Gradual warming trend expected later in the week
3. Dry for most areas through the period
- Flurries possible MON, low chance for snow showers
- Lake effect showers MON-TUE into NW IN, some snow may mix in
"Cold and blustery" will be the story for the start of the
extended forecast period as the upper trough digs into the Great
Lakes Region quickly developing into a closed upper low. Heading
into Sunday night steady northwest winds will likely persist
through the overnight hours. This strong cold air advection will
help push overnight temperatures into the upper 20s to lower 30s
away from Lake Michigan. Lingering stratus may limit some of the
cooling, but the cold advection should make up for any reduction
in radiational cooling. Cannot rule out a few flurries or isolated
snow showers during the overnight period.
The daytime hours on Monday will be notably cold and blustery
(for this time of year) with highs struggling to warm out of the
lower 40s with low clouds hanging around all day. Strong winds
gusting to 30-40 mph will keep wind chill values in the 20s to
lower 30s. Time to break out the winter clothing if you haven`t
already!
Given the cold airmass in place and steep low-level lapse rates,
the cloud layer will be cold enough to support at least flurries.
Given support for lift beneath a strong short-wave rounding the
closed low overhead, if we can get a bit deeper cloud layer there
could even be a few more robust snow showers across NE IL. There
are hints of this into Sunday night toward the end of the 12Z HRRR
and supported by the past couple runs of the ECMWF. However, the
GFS/NAM suites are leaning less favorable for anything more than
flurries at this range. Still something to keep an eye on!
Regardless, the signal for lake effect showers remains favorable
for portions of northwest Indiana on Monday, especially into
northern Porter County. Some snowflakes again could mix in at
times in the lake effect showers as well.
Tuesday it looks like the lake effect precipitation axis begins
to shift a bit further east, but there may be a few remnant
showers into Porter County IN through the AM. While strong
northwesterly winds will persist through Tuesday, clearing skies
should help us warm up a bit more than Monday, with highs in the
mid 40s. Wind chills will likely still be in the mid 30s to near
40, however.
Even though Lake Michigan water levels are a foot lower than
where they were last year, the persistent strong north northwest
winds will result in large waves building across southern Lake
Michigan and accordingly increases the risk for beach erosion and
minor lakeshore flooding along the Indiana shore. Interests along
the Indiana shore, especially in areas that have been prone to
flooding in the past should monitor the forecast the next couple
days.
Wednesday will remain unseasonably cool with forecast highs still
in the mid to upper 40s. Winds do begin to turn more westerly
helping ease the strong cold air advection of the past couple
days. Later in the week the upper trough begins to shift east as
the western ridge starts to break down. Accordingly, southerly
warm advection will return and help highs warm into the 50s
Thursday and Friday, with 60s possibly making a return for the
start of next weekend.
Petr
&&
.CLIMATE...
Issued at 235 PM CDT Sat Oct 15 2022
Here are the current records in place for Monday and Tuesday.
Most records appear to be safe, with the record cold max for
Rockford for Monday 10/17 being the most likely record to be
threatened. Though temperatures will not be all that much above
the other records...
October 17 October 18
Record Cold Record Low Record Cold Record Low
Maximum Maximum
Chicago 40 (1880) 26 (1948) 38 (1930) 20 (1948)
Rockford 44 (2002) 24 (1992) 41 (1972) 19 (1952)
Petr/Izzi
&&
.AVIATION...
For the 00Z TAFs...
Aviation Forecast Concerns:
* Marginal weak LLWS possible this evening.
* Breezy west-northwest winds Sunday, with gusts near 25 kts
especially during the afternoon.
Surface low pressure will pass north of the Great Lakes region
tonight, with a trailing cold front pushing southeast across the
terminals after midnight. Southwest winds ahead of the front have
diminished with sunset already, though a brief period of 30-35 kt
winds in the 1500-2000 foot AGL layer may make for some marginal
LLWS conditions through about midnight. Given sustained surface
winds near 10 kts, this is below criteria for including LLWS in
the TAFs however. Surface winds turn west-northwest behind the
front during the pre-dawn hours, with the cold frontal passage
otherwise expected to be uneventful.
West-northwest winds (290-310 deg) will become gusty once again
late Sunday morning, with gusts around 25 kts persisting through
the afternoon and likely in to the evening within a strong cold
air advection regime. Will likely see a VFR stratocu deck develop
by midday in the 4000 foot AGL range, and this too looks to linger
into the evening hours. Can`t completely rule out a stray sprinkle
from this deck Sunday afternoon/evening, though chances of any
meaningful precip appears low.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...nearshore waters until 4 AM Sunday.
Gale Watch...LMZ740-LMZ741-LMZ742-LMZ743...10 AM Monday to 10 AM
Tuesday.
Gale Watch...LMZ744-LMZ745...midnight Monday to 10 AM Tuesday.
&&
$$
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Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
826 PM PDT Sat Oct 15 2022
.SYNOPSIS...15/128 PM.
Showery and thunderstorms are possible this afternoon, especially
in Los Angeles County, with periods of heavy rain. Dry weather
expected Sunday with a rapid warming trend through next
Wednesday.
&&
.SHORT TERM (SAT-TUE)...15/822 PM.
Convection today was confined to the eastern portion of LA county
and points to the east and south. Shout out to the HRRR
deterministic MDL for really nailing the fcst. While some storms
did have fairly impressive rainfall rates they were moving at a
good clip and rainfall totals were on the low side with only a
couple of stations reporting amounts between .4 and .5 of an inch.
Showers and TSTMs will persist through this evening but will only
affect eastern LA county.
It was another cloudy and cool day as the upper low acted like a
super eddy and kept low clouds in across all coasts and vlys all
day long. This cloud cover along with lowering hgts lowered
Woodland Hills max temp to 69 degrees the first time the max temp
there was in the 60s since May 20th.
Huge marine layer was not at all disrupted by the convection and
now covers all the csts, vlys and coastal slopes. The good news is
that without the upper low "super eddy" and the addition of
offshore trends will allow for much better if not total clearing
by afternoon. The extra sunshine and weaker onshore flow will
bring 2 to 5 degrees of warming to most of the area (the SLO
interior will likely see 8 degrees of warming)
An update will be issued to adjust the pops and shower/TSTM
coverage.
***From Previous Discussion***
Offshore trends expected to continue Monday and Tuesday leading to
a rapid warming trend with temperatures getting back into the 90s
for the valleys and 70s and 80s for the coast.
.LONG TERM (WED-SAT)...15/141 PM.
Good agreement between the ensembles through later next week,
though less so with chances for precip. The warming trend is
expected to peak on Wednesday before another slow moving and
partially cutoff upper low approaches from the west. Both the GEFS
and EPS ensembles show a trough moving through Thursday into
Friday, though the GEFS is noticeably wetter with quite a bit of
instability, particularly once again across LA County. The EPS
much less so which explains the disparity in the precip output
which is definitely higher in the GEFS and almost absent in the
EPS. So for now just very minimal pops are in the forecast and
mostly in the mountains. Will hopefully get better consensus early
next week. Certainly higher confidence in a cooling trend for
late week.
&&
.AVIATION...15/1747Z.
At 1516Z at KLAX, there was a 4000 foot deep moist layer capped by
a strong inversion. The top of the inversion was at 6400 feet
with a temperature of 14 degrees C.
Good confidence in KPMD/KWJF TAFs through 18Z with moderate
confidence between 20-03Z with a 20-30 percent chance of
SHRA/TSRA.
Low confidence in other TAFs, especially KSBA and south, including
KLAX. Cigs/vsby may bounce between MVFR/IFR KSBA and south
including KLAX, and low MVFR to LIFR to the north. Drizzle is
possible for terminals KSBA and south through 20Z. SHRA/TSRA
coverage may (10-20 percent chance) increase across this area as
early as this time frame, but most likely between 20-03Z and
focused across LA county (30-50 percent chance) with a 20-30
percent chance for KSBA, KOXR, and KCMA. Slow to no clearing
expected for coast and coastal valley terminals, except for LA
county terminals, which have about a 50 percent chance of
scattering out between 20-03Z.
KLAX...Low confidence in TAF. There is a 30 percent chance that
cigs do no scatter out after 20Z. There is a 20 percent chance of
SHRA/TSRA 18Z-22Z with a 30 percent chance 22Z-03Z. No
significant easterly wind component is expected outside of TSRA.
KBUR...Low confidence in TAF. Cigs may at least briefly scatter
out as early as 19Z. There is a 20 percent chance of a shower or
TSRA 18Z-22Z increasing to 30 percent 22Z-02Z.
&&
.MARINE...15/825 PM.
Isolated thunderstorms will continue across zone 655 tonight.
Any thunderstorms that do form will generally come from the
northeast direction. Gusty and erratic winds, steep seas, and
frequent lightning will be possible near stronger thunderstorms.
There is a 30 percent chance of Small Craft Advisory (SCA)
conditions focused across portions of the outer waters at times
Monday night through Wednesday.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...MW/Rorke
AVIATION...Sweet/Munroe
MARINE...Gomberg
SYNOPSIS...MW
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox
Area Forecast Discussion
National Weather Service Marquette MI
1201 AM EDT Sun Oct 16 2022
.SHORT TERM...(Through Tonight)
Issued at 241 PM EDT SAT OCT 15 2022
Latest water vapor imagery and RAP analysis show a broad mid-level
trough extending from central Canada into the Great Lakes region
with an upstream shortwave of interest diving southeast from
southern Manitoba/NW Ontario. Weak forcing ahead of this shortwave
and WAA/isentropic ascent along or ahead of its associated sfc
trough has led to scattered rain/snow showers mainly along the WI
border counties this afternoon and it looks like these showers could
continue into the early evening hours. There have also been some
ongoing scattered lake effect showers in a westerly flow over Lake
Superior today which have mainly affected portions of the Keweenaw
and the far eastern Lake Superior shoreline of the UP. These lake
showers will also continue into tonight and could increase in
coverage and push farther inland later this evening and overnight as
the passage of a weak trough/cold front shift winds more
northwesterly and CAA lowers 850 mb temps 1-2C over the western
lake. Looks like the best chance for a light mix of rain and snow
showers tonight will be over the western counties and east half
shoreline areas of the UP. Min temps tonight will generally be in
the lower to mid 30s under mostly cloudy skies.
.LONG TERM...(Sunday through Saturday)
Issued at 402 PM EDT SAT OCT 15 2022
Some lake-effect rain showers (with some snow mixing in at times
over the west) over the NW flow areas starts out the extended
forecast period Sunday. Lake-effect showers become more numerous and
intense across the area Sunday afternoon as inversion heights grow
up to ~10 kft in response to a low pressure from northern Ontario
dropping into Lake Huron Sunday and Sunday night. As we move into
Sunday night, expect the rain to transition to snow from west to
east as a cold front drops south from Canada. With 850mb temps
around -10C from Ironwood to Marquette around 06z Monday, delta-T`s
near 20C, and upslope flow in the NNW snow belts, expect heavy, wet
snowfall to occur in the interior west and north central Sunday
night into Monday. Several inches are expected over the Michigamme
Highlands of Marquette and Baraga counties Sunday night, with minor
accumulations possible near the western lakeshores as well as sfc
temps reach freezing. In addition to the snowfall, with winds
increasing up to 45 mph, particularly near the Lake Superior
shoreline, expect blowing snow to become a concern. As an inverted
trough moves through Lake Superior Monday morning, expect the heavy,
wet snow to continue over the north central and windy conditions to
continue across the entirety of the UP. Therefore, travel is not
advisable Monday morning over the west and north central UP, as
slick roads would make travel hazardous. In addition, the windy
conditions, in combination with the heavy, wet snow, could also
cause some widespread power outages.
Widespread lake-enhanced snowfall over the north snow belts,
particularly over the north central continues Monday into Tuesday as
the low pressure over Lake Huron slowly moves over to Georgian Bay,
allowing strong northerly winds and blowing snow to continue over
the region. With inversion heights slowly dropping from 20 to less
than 10 kft Monday into Monday, expect the heavy snowfall to slowly
taper off as we move into the middle of the week. The greatest
snowfall looks to occur over the Michigamme Highlands, as upslope
convergent flow looks to squeeze out the moisture in the atmosphere
quite effectively; would not be surprised if we saw double digit
storm snowfall totals by the end of the event over the Michigamme
Highlands. As the low lifts out towards Quebec Tuesday, expect drier
air to enter into the region, transitioning the snow (and rain in
the east) to lake-effect before it ends Tuesday night and Wednesday
from west to east.
The next shortwave that looks to effect our CWA looks to occur
Wednesday night and Thursday, which looks to bring some light rain
and snow showers across mainly the eastern CWA. After this, expect
temps to warm as the pattern shifts away from the troughing that we
are currently experiencing and warm Gulf of Mexico air moves in.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1200 AM EDT SUN OCT 16 2022
Despite some brief fluctuations to VFR at times early this morning,
MVFR conditions will be the predominant flight category for the
duration of the TAF period. Persistent lake effect showers will
continue to impact the TAF sites today with some transition to snow
early this morning, especially as winds shift to the northwest
behind a trough/cold front. Those northwesterly winds will also
become strong at KIWD and KCMX this morning with gusts up to 23 kts.
Further intensification can be expected by this afternoon as
sustained speeds top off in the 12 to 15 kt range with gusts up to
29 kts.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 402 PM EDT SAT OCT 15 2022
Westerly wind gusts 20-25kt across the lake will become northwest
tonight from west to east as a low pressure trough pushes across the
lake and will continue northwest 20-25 kt into Sun morning. Later
Sun thru Tue, low pressure develops in the vicinity of northern Lake
Huron while high pressure ridge builds south onto the Northern
Plains. NW winds increase to 35-40kt gales across the western lake
by Sunday evening then increase to high-end 45kt northerly gales
across the central lake late Sun night through Tuesday morning.
Northerly storm force gusts are possible, mainly across the east-
central lake Monday night into early Tuesday. North winds slowly
diminish below gales from west to east on Tuesday into Tuesday night
and then become west-northwest at 15-25 knots on Wednesday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning from 8 PM this evening to 11 PM EDT Monday for
LSZ162.
Gale Warning from 8 PM this evening to 8 PM EDT Tuesday for
LSZ240>244-263-264.
Gale Warning from 11 PM this evening to 2 AM EDT Wednesday for
LSZ245>250-265-266.
Gale Warning from 5 AM Monday to 2 AM EDT Wednesday for LSZ251-
267.
Lake Michigan...
Gale Watch from late tonight through Tuesday evening for LMZ221-
248-250.
&&
$$
SHORT TERM...Voss
LONG TERM...TAP
AVIATION...TDUD
MARINE...Voss