Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/18/22
Area Forecast Discussion
National Weather Service Boston/Norton MA
1039 PM EDT Mon Oct 17 2022
.SYNOPSIS...
Cold frontal passage brings the chance for more widespread rain
tonight and early Tuesday. Gusty south-southeast winds will
gradually subside as the front pulls away Tuesday afternoon.
Seasonably chilly air mid week, with highs in the 50s and
several nights in the 30s will lead to milder conditions by the
weekend. At this time, it looks dry beyond Tuesday evening!
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Main changes this evening to adjust rainfall chances and
timing. relied rather heavily upon the latest HRRR runs, which
appeared to be handling it well. A few instances of lightning,
but most of the higher reflectivity echoes were topping out just
below -10C. Not expecting many thunderstorms overnight with
meager amounts of buoyancy. Analyzed mid level lapse rates were
steeper than 6C, which is rather potent for this time of day and
year.
Expecting focus to shift from eastern CT and north central MA
to RI and more of eastern MA as a cold front crawls its way
across southern New England. Likely will take all night for this
front to reach the coast.
730 pm update...
Second surge of moisture and precipitation is on our doorstep,
moving into western MA/CT in the last hour. Rain will pick up
across the region over the next 5-7 hours. Main change with this
evening`s update was to slightly adjust the timing of the
arrival of the heavier rain based on radar.
Previous Discussion...
Rain showers will linger early this evening before a second
surge of more widespread precipitation develops ahead of the
incoming cold front along an emerging low pressure system. Most
short term guidance, like the HRRR and the NAM, pinpoint areas
south and east of Worcester as the area having the potential to
receive the most precipitation overnight. Some modest
instability, given it is mid- October, of 200J/kg CAPE and K
index values nearing 35 across SE MA and Cape Cod may support a
few rumbles of thunder. HI-Res guidance does show the potential
development of a convective line between 05- 12Z tomorrow,
mainly centered across the Cape. It is here we are expecting the
highest rainfall totals, with HREF mean ensemble probs of 1"
QPF over 3 hours exceeding 50%. This spells good news for the
region, as portions of Cape have missed out on some of bouts of
precipitation that have impacted interior southern New England
over the past month.
Early Tuesday morning, a low level jet will develop along the
frontal boundary. While the NAM seems out to lunch, with a 65kt
jet over Boston, a 30-35 kt jet appears likely. Gusts will
likely mix down in convective cells, but given the jet develops
pre- sunrise, we are not expecting mixing to reach it`s full
potential until the jet begins to move offshore later in the
day. Still, gusts to 30 kt are possible across the Cape and the
waters.
Clearing will begin to develop to our west before sunrise, but
the front will be slow to pull away. Radiational cooling
potential is not great tonight, given cloud cover, so the
thought is lows will linger between the mid 40s at elevation to
the low 60s across the Cape.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
The thunderstorms and showers mentioned in the near term discussion
will continue through about mid-day as the slow moving cold front
begins to move out to sea. Some guidance suggests that there will be
a tertiary round of precipitation impacting the Cape Tuesday
afternoon, but most portions of interior southern New England will
be precip free after about 15Z.
As mentioned, clearing is expected to occur very slowly and while
portions of western, southern New England break into sunshine
late Tuesday morning, it may take all day for patches of sun to
develop across eastern MA and RI. One may think that areas that
break out into sunshine will achieve the highest temperatures
Tuesday, but such is not the case as 925mb temps plummet to
between 3-5C behind the front. So, while solar heating will help
temps rise to the mid-50s across our western zones, the warmest
part of our CWA will be under the cloud cover in eastern MA.
925mb temperatures between 10-14 degrees will help temps surge
to the mix to upper 60s across Cape Cod and Nantucket!
Dewpoints crater behind the front, and clearing conditions Tuesday
set us up for an optimal radiational cooling night Wednesday night.
Winds will decouple after sunset, and with cold air aloft, to the
tune of 0-2C thanks to the very deep trough and cut off low just to
our west, temperatures will fall back into the 30s away from the
coast. Given the coldest temperatures will occur across NW MA, where
our Frost/Freeze program has ended for the season, and the
Frost/Freeze risk isolated to between 10 and 12Z elsewhere, we opted
to forgo a frost advisory. Later shifts may re-evaluate based on
new guidance.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Highlights...
* Dry weather continues through at least Saturday. There is
potential for our next system by Sunday but low confidence.
* Cooler than normal temperatures persist through Thursday, steadily
warming up back into the upper 60s by the weekend.
Details...
Precipitation...
Southern New England should stay dry through all of the extended
forecast period. Even though we`ll be in the vicinity of a deep
trough to our west on Wednesday and Thursday, BUFKIT soundings show
a very dry atmospheric column so no precipitation is expected.
Beyond Thursday meridional flow becomes more zonal through the
weekend while high pressure builds in at the surface. Given this
there will be no significant disturbances to bring any rain. The one
low probability exception could be a coastal low around Sunday, but
the deterministic ECMWF continues to be an outlier in showing this,
so not giving much credence to that. The notable effect of the
trough Wednesday/Thursday will be breezy winds. A 25-35 kt low level
jet develops at 925 mb which will mix down gusts of 25 to 35 mph on
Wednesday and Thursday.
Temperatures...
Cooler than normal temperatures persist on Wednesday and Thursday
thanks to a very cool airmass overhead with 850 mb temperatures
below zero. This will translate to highs in the 50s each day, save
for low 60s on the Cape and islands. It will likely feel cooler
thanks to the breezy winds. As that zonal flow moves overhead it
allows for an intrusion of much warmer air as we go into the weekend
(850 mb temps back up to +8 to 10C). This sets us up for a nice, dry
weekend with highs in the upper 60s which persist into the start of
the new work week.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight... High confidence in trends, moderate confidence in
timing.
MVFR/IFR conditions overnight, gradually improving to VFR across
our western terminals before sunrise. Terminals across our
eastern zones will experience reduced vsbys due to rains showers
through 12z. Isolated thunderstorms may impact Nantucket,
Hyannis, and Falmouth. Winds will pick up from the south ahead
of a cold front. A low level jet at 925mb will generate low
level wind shear for across the Cape and Islands.
Tuesday...
MVFR/IFR conditions to start, improving to VFR from W to E
through the day as a cold front pushes through. Showers ending
last towards the east coast late in the day. Winds shift to the
SW/W at 5-10 kts once the front passes through.
KBOS Terminal...High confidence in trends, but only moderate
confidence in timing. Not out of the question there could be a
rumble of thunder or two late tonight. Have held off on a
mention as am not confident enough on the coverage.
KBDL Terminal...High confidence in trends, but only moderate
confidence in timing.
Outlook /Tuesday Night through Saturday/...
Tuesday Night: VFR.
Wednesday through Thursday Night: VFR. Breezy.
Friday through Saturday: VFR.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
A cold front approaches from the west as southerly winds between
10-15 kt gust to between 25 and 30 kt through Tuesday morning.
Low confidence in gale force conditions between 06-12Z Tuesday
ahead of the cold front. Gusts over 30kt will be, generally,
isolated to convective cells, and given the short duration of
gale potential, we opted to keep small craft advisories in
place. Later shifts may re- evaluate but thinking any gales
could be covered by marine weather statements.
Winds become westerly, generally gusting below 15 kt, behind the
frontal passage Tuesday night. While winds begin to subside, it
will take some time for waves to fall below 5 ft across the
outer waters. It is likely small crafts will need to be extended
beyond their current length.
Outlook /Tuesday Night through Saturday/...
Tuesday Night: Winds less than 25 kt. Areas of rough seas.
Wednesday through Wednesday Night: Winds less than 25 kt. Seas
up to 5 ft.
Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.
Thursday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.
Friday through Saturday: Winds less than 25 kt. Seas locally
approaching 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT Tuesday for ANZ254>256.
&&
$$
SYNOPSIS...BW/KS
NEAR TERM...Belk/BW/KS
SHORT TERM...KS
LONG TERM...BW
AVIATION...Belk/BW/KS
MARINE...Belk/BW/KS
Area Forecast Discussion
National Weather Service Grand Forks ND
1022 PM CDT Mon Oct 17 2022
.UPDATE...
Issued at 1020 PM CDT Mon Oct 17 2022
Nothing new going on to change the fcst. The same questions remain
in regards to clouds from western Manitoba south to Carrington ND.
Band is shrinking in width but still there. Models want to get rid
of it too soon. It seems to be in the area where winds go from
north to southeast in the sfc ridge axis. Cloud bases are 10k ft
agl so impacts to aviation is minimal. Added a bit more sky cover
to far east as clouds moving SSW from Ontario continue to skirt
Baudette to Waskish to Walker MN.
UPDATE Issued at 654 PM CDT Mon Oct 17 2022
Narrow band of AC moving south from western Manitoba into Cando
and Rugby to Harvey ND. HRRR has cloud area shifting south
overnight and that area clearing. But that remains to be seen.
Devils Lake itself may get into the clouds. If clouds linger this
would impact temps. Otherwise clear sky eastern ND into western
MN. CU Baudette to Bemidji to Wadena scattered out and almost
cleared out. With light winds, dry airmass in place and clear sky
overnight ideal cooling with lows in the teens very likely,
exception could be Devils Lake area with clouds.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 247 PM CDT Mon Oct 17 2022
Temperatures remain the main challenge for the period.
Meridional flow continues over the Northern Plains the the upper
low digs into the Great Lakes. Surface high pressure extends from
Manitoba into the Red River Valley and that will change little as
we head into the overnight period. Cloud cover has pushed off into
central ND and our western counties will be clear with light
winds overnight as well as the Red River Valley. Temps should fall
into the low to mid teens. Less certain is the Lake of the Woods
area, where there continues to be some lingering stratocu and CAMs
show a signal for radar returns coming off of the lakes. Not
highly confident in any precip reaching the ground, but have a bit
more clouds and slightly higher temps in our far eastern counties.
Temps tomorrow will be a couple of degrees higher than today in
the upper 30s to low 40s with cold air advection weakening and
the air mass starting to modify. Still below average, but the
warming trend will start. True warm air advection begins to kick
in Tuesday night, and there should be a bit more cloud cover as a
weak shortwave comes down the northerly flow. Thus, overnight lows
should stay a bit higher in the 20s.
.LONG TERM...(Wednesday through Monday)
Issued at 247 PM CDT Mon Oct 17 2022
1.) A mostly quiet long term is in store for us with gradually
warming temperatures by the end of the week.
2.) There is a strong ensemble signal for a system late this weekend
into early next week that could bring precipitation to the area.
Numerous uncertainties still exist that prevent specific details on
potential impacts.
METEOROLOGICAL ANALYSIS...
Large scale ridging will dominate the beginning of the long term
period. This should allow temperatures to warm up slowly throughout
the week to back into the 60s by the end of the work week. NBM
temperatures indicate a very small temperature spread through at
least Sunday, indicating high confidence in high temperatures maxing
out in the upper 60s and low 70s.
Ensembles have very high confidence in large scale ridging beginning
to break down and begin to usher in a hefty wave at the end of the
long term period. Ensemble forecast percentiles all reflect a very
strong signal for a strongly forced system, with minimum SLP
percentiles showing up across the northern plains by Monday. While
this does lend confidence to at least the existence of some potent
troughing, guidance breaks down heavily on location of the trough,
which subsequently leads to high uncertainty in impacts for our
area. Location of the trough and attached surface low would cause
impacts to range from potentially no precipitation to rain to snow.
For the minimum expectations right now, the general model consensus
is an upper trough will exist with strong forcing. It just becomes a
matter of where and how intense.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 654 PM CDT Mon Oct 17 2022
Skies clear in the RRV into Tuesday with a north wind 4 to 8 kts.
DVL area on the edge of mid clouds dropping south from Manitoba.
CU going away around Bemidji.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Riddle
SHORT TERM...JR
LONG TERM...Perroux
AVIATION...Riddle
Area Forecast Discussion
National Weather Service Wilmington NC
1030 PM EDT Mon Oct 17 2022
.SYNOPSIS...
A mainly dry cold front will move through tonight. Cold and dry
high pressure is then expected Tuesday into late week with
frost possible inland each morning through midweek. Low pressure
could develop offshore this weekend.
&&
.UPDATE...
Have lowered POPs to 20 percent or less, ie. isolated shra or
tsra, with the last of the activity off the ILM NC coast early
in the pre-dawn hrs. Cold front dropping SE-ward, should clear
the ILM SC Coast between 12am and 2 am, and the ILM NC Coast
between 1am and 3am, via latest HRRR model run. Ptly or variably
cloudy ahead of the cold front with high stratocu or altocu the
primary clouds, lower based clouds if any pcpn occurs. Min temps
just a tweak, if any, needed. Some tweaks to the overnight into
daylight Tue winds with SCA still good til 6am Tue. May need to
adjust further if the combined CAA and tightened sfc pg keep
winds active into daylight Tue. Seas generally 3 to 5 ft
overnight, with 6 footers possible off Cape Fear.
&&
.NEAR TERM /THROUGH TUESDAY/...
The lack of cumulus development suggests that the area failed to
destabilize appreciably and the SPC mesoanalysis page shows us
capped to MLCAPE. The window for any convection developing appears
to be closing fast. Hi res models show that perhaps the immediate
Cape Fear region sees isolated showers this evening into early
tonight but not anticipating thunder. The strong cold front enters
the CWA close to midnight and the cold dry air starts pouring in.
Tuesday afternoon may turn a bit breezy as the 850 winds veer and
line up better with the surface flow, though overall low level wind
fields will be weakening. Lows tonight will actually be seasonably
cool but Tuesday`s highs will be some 10 degrees below normal as the
CAA continues.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Forecast confidence: Moderate to high
Surface high pressure will slowly build into the area from the west
while troughing persists aloft. Main forecast challenges will be
temperatures and frost potential. Confidence is high that
temperatures will be well below normal through the period. Lows
should mainly be in the mid to upper 30s inland Tuesday and
Wednesday nights with some frost possible, especially Wednesday
night when the high pressure is closer and winds will be lighter.
There is even a low risk for isolated freezing temperatures Tue/Wed
nights in the normally colder inland outlying areas, especially Wed
night when radiational cooling conditions should be most favorable.
Could even be near record lows for Oct 19/20, especially at
Florence. Could even see some frost well inland again Thursday
night.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Forecast confidence: Moderate through Friday night, then low to
moderate into early next week.
Surface high pressure should prevail inland with possible low pressure
developing offshore. Best moisture and convergence should be closer
to the coast where there could be some showers. Temperatures should
start out a bit below normal before moderating to near to above normal
levels.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR to dominate this 24 hr period. CFP slated for late this
evening across inland terminals and early in the pre-dawn Tue
hrs for the coastal terminals. Moisture limited to altocu decks
or high stratocu decks prior to and atleast 5 hrs after FROPA.
Chance for pcpn associated with the CFP are too low to even
include vicinity group. Winds will veer from SSW- SW to W 5 to
10 kt prior to the CFP...NW- NNW 5 to 10 kt with initial g15 kt
possible after the CFP. From 14Z thru 24Z, looking at mainly SKC
with NW around 10 kt occasional g15 kt as CAA and a tightened
sfc pg combine. Look for winds to diminish to WNW-NW 5 kt or
less after 23Z.
Extended Outlook...High confidence in prevailing VFR conditions.
&&
.MARINE...
Through Tuesday...Marginal Small Craft advisory ongoing in the
prefrontal flow regime with occasional gusts. Wind swings around to
the NW with FROPA later tonight as low level wind fields start to
weaken. No changes have been made to the advisory timing with the
afternoon package. As dominant wave height abates on Tuesday
dominant period decreases by about a second from the wind shift.
Tuesday night through Saturday: Forecast confidence this period is
moderate to high through Friday night, then low to moderate
Saturday. Breezy conditions will linger into Wednesday before high
pressure builds more overhead with benign conditions into Friday
night. A tightening pressure gradient between inland high pressure
and possible offshore low pressure should lead to deteriorating
conditions later Friday night and Saturday, however the extent
to which is uncertain at this time.
&&
.CLIMATE...
Record lows for Oct 19...
ILM: 35/1992
FLO: 34/1948
LBT: 28/1982
MYR: 36/1948
Record lows for Oct 20...
ILM: 35/1992
FLO: 34/1992
LBT: 28/1986
MYR: 36/1992
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until 6 AM EDT Tuesday for AMZ250-252-254-
256.
&&
$$
SYNOPSIS...ILM
UPDATE...DCH
NEAR TERM...MBB
SHORT TERM...RJB
LONG TERM...RJB
AVIATION...DCH/RJB
MARINE...MBB/RJB
CLIMATE...RJB
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
818 PM EDT Mon Oct 17 2022
.SYNOPSIS...
A large upper level trough continues to be the dominant weather influencer
for the Ohio Valley for the first half of the week. Strong northwesterly
flow will allow for temperatures to drop 15 to 20 degrees below normal and
scattered showers mid week may have some snow mixed in. A warm up is
expected near the end of the work week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A convective lake enhanced rain/snow band is persisting across
northern Indiana early this evening. The southern edge of this
is weaker but has been encroaching upon northwest portions of
our area. The latest HRRR keeps this band going through the
evening hours while slowly retrograding it back to the west. As
a result have nudged up pops into likely category for our far
northwest areas and will bring a slight chance/chance across
much of the rest of our western areas over the next few hours.
Temperatures across our northwest have dropped into the upper
30s and will likely continue to fall into the mid 30s through
the late evening as we continue to get some evaporative cooling
on top of the CAA. Between this and some wet bulb effect, some
snow will mix in with the rain with perhaps all snow for a
period time through the evening hours across our far northwest.
Ground temperatures are warm but suppose a light dusting on
grassy/elevated surfaces cannot be ruled out across portions of
our northwest.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Synoptically, a large upper level low continues to slowly shift
southeast while its expansive trough digs into the Ohio Valley and
associated surface low continues to move eastward through Ontario
toward Quebec. A secondary cold front drops southeast through the
upper midwest and is forecast to travel through the Ohio Valley
overnight into Tuesday morning, ushering in deep northwesterly flow
and a colder Canadian air mass.
After much collaboration with neighbors, have decided to keep the
Freeze Warning in place for our southern counties overnight and
have cancelled Freeze Watch for northern counties. Overnight
lows in the south will likely drop to 30/31 degrees where
partial cloud clearing may occur and 34/35 in the north where
cloud cover is thicker.
Given the cyclonic system and orientation of northwesterly flow
pulling additional moisture off of the Great Lakes, have
included the chance for pcpn overnight, particularly in northern
counties that are closer in proximity to the low. Pcpn will
primarily fall as light rain showers, however, cannot rule out
some snow mixing in during morning hours. Surface temperatures
should be above freezing, which will melt any frozen pcpn
quickly.
Strong CAA helps keep temperatures about 15 degrees below
climatological norms for Tuesday, with highs only reaching the mid
40s during the day. As the upper level feature stalls and spins, the
chance for precipitation persists....additionally, breezy conditions
continue with gusts in the north up to 30 mph.
CAA continues Tuesday night and overnight lows drop into the low
30s. The chance for showers lingers overnight into Wednesday as the
system continues its slow meander east. Again, a rain snow mix is
likely.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As low pressure exits slowly northeast on Wednesday, showers may
linger across northern locations, with snow possibly mixing in
Wednesday morning. Brisk winds are likely at all locations in the
tight pressure gradient surrounding the low. A large area of high
pressure building in behind the low should then provide dry weather
conditions Thursday into Monday. The next frontal system may bring a
chance of showers later on Monday.
A warming trend will be observed as geopotential heights increase
behind the low, while warm advection takes over near the surface on
southwest flow developing around the high. A chilly start to the
period calls for highs in the mid 40s to low 50s Wednesday, rising
to the low and mid 50s Thursday, the 60s Friday, before reaching the
70s Saturday through Monday.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Lake effect rain/snow band will continue to affect
northwest/western portions of our area through this evening so
it will be tough to rule out a few showers at the western TAF
sites. Will cover this threat with a VCSH. Otherwise, MVFR cigs
will continue to spread south across our area through the
overnight hours with MVFR cigs then persisting into the morning
hours on Tuesday. MVFR cigs will gradually lift into VFR through
the afternoon hours but in continued cyclonic flow, scattered
showers will be heading into the afternoon hours. Will again
cover this with a VCSH at the northern TAF sites. Westerly winds
will remain gusty in the 20 to 25 mph range through much of the
TAF period.
OUTLOOK...MVFR cigs possible into Tuesday night into Wednesday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Freeze Warning until 10 AM EDT Tuesday for OHZ042-060>064-
070>074-077>082-088.
KY...Freeze Warning until 10 AM EDT Tuesday for KYZ089>100.
IN...Freeze Warning until 10 AM EDT Tuesday for INZ050-058-059-066-
073>075-080.
&&
$$
SYNOPSIS...CA
NEAR TERM...JGL
SHORT TERM...CA
LONG TERM...Coniglio
AVIATION...JGL
Area Forecast Discussion...UPDATED
National Weather Service Indianapolis IN
951 PM EDT Mon Oct 17 2022
.Forecast Update...
Issued at 951 PM EDT Mon Oct 17 2022
A significant lake effect precipitation event is ongoing across far
southwest Michigan into northern Indiana. Two dominant bands are
still evident with reports northwest of Fort Wayne of accumulation,
and some tree limb damage due to heavy/wet snow weight on trees that
still have foliage. There remains uncertainty on the details with
the downstream end of these bands, but hi-res models do show a
slightly westward shift with subtle veering flow. Therefore, north-
central and northeast portions of the area will have the highest
probabilities of precipitation tonight. The downstream extent of
meaningful/measurable amounts is in question and will at least
partially be a function of the bands` ability to consolidate.
Nevertheless, the strongest mesoscale forcing and vertical theta-e
differential will keep the heaviest rates to our north, tapering
gradually south-southeastward. The thermal profile will be marginal
for snow by traditional >0 wet bulb heights, though steep low-level
lapse rates suggest a dominant snow precipitation type. Weaker echos
across central Indiana recently have produced a couple of reports of
light snow already. Transient east-west sloshing of mesoscale
banding driven by subtle backing/veering of low-level winds, and
relatively lighter precipitation rates should keep amounts light. In
a reasonable worst case locally a couple inches may accumulate,
primarily across north-central and northeast portions of central
Indiana. Warm ground and pavement temperatures should preclude
travel impacts.
&&
.Short Term...(This evening through Tuesday)
Issued at 301 PM EDT Mon Oct 17 2022
...FREEZE WARNING TONIGHT...
...SNOW SHOWERS TONIGHT INTO TUESDAY, MAINLY NORTH AND EAST...
Remainder of the Afternoon...
Isolated to scattered snow showers mixed with graupel have been
reported over northeastern and east central parts of central Indiana
late this morning and into the afternoon associated with cyclonic
flow around a potent Great Lakes vortex and within an area of 7 plus
degree C/km lapse rates and in left exit region of a 110 knot upper
jet streak over southern Indiana. KIND Dual Pol and low freezing
level from MIE sounding from the RAP both support mostly snow from
these cells. That said, the cells were starting to weaken and were
moving ESE toward the Ohio border. We may be able to drop PoPs for
the rest of the afternoon if they are out of central Indiana in the
next hour. Meanwhile, winds have been gusting to 25 to near 35 mph
as advertised due to tight pressure gradient and deep mixing. Still
some concern for wildfires over mainly southwestern locales through
early evening, but so far the RH has remained above 30% as cloud
cover and cold advection have keep temperatures in the 40s.
Tonight...
Look for the cellular clouds to dissipate by sunset but leading edge
of a stratocumulus deck is already over northwestern parts of
central Indiana and looks like it will reach the Interstate 70
corridor by early evening. This could hinder the expected freezing
temperatures for areas insulated under it. That said, with strong
cold advection, will keep the Freeze Warning going. Also of
concern will be more rain and snow showers as an impressive lake
effect event is setting up with strong moisture convergence and
instability over Lake Michigan along with a long fetch associated
with 850 millibar 50 knot jet max. Healthy NNW winds will steer
these showers all into at least northern parts of central Indiana
this evening and overnight with light accumulation possible. Would
not rule out rain mixing in early, but snow looks much more
likely with the sounding profile. With the grounds relatively
warm, accumulation will be light and limited to grassy and
elevated surfaces. Kept likely PoPs over Howard and Carroll
counties with small chances along the I-70 corridor and dry far
southwest.
Tuesday...
Low level winds will shift more to the WNW Tuesday which suggest
lake effect showers will be confined to mainly far northeastern
parts. Meanwhile, areas southwest of I-74 will see some sunshine
being in closer proximity to Plains high pressure. Sounding profiles
suggest any shower will be mostly snow early and then transition to
snow during the afternoon as temperatures gradually rise to the
middle 40s.
&&
.Long Term...(Tuesday night through Monday)
Issued at 301 PM EDT Mon Oct 17 2022
* Freezing temperatures expected over the next few nights,
particularly Wednesday Night which could officially end growing
season
* Warming temperatures late week into the weekend
An anomalously deep closed low will remain across the eastern Great
Lakes Region before it steadily pulls north/northeastward Wednesday
into late week. Light snow is possible across northeastern counties
overnight Tuesday into early Wednesday as lake enhanced moisture
pushes over the area. NW Flow should limit any precipitation to far
northeastern counties. Surface temperatures will be well above
freezing with no accumulations expected.
Temperatures will remain below average through Thursday as NW flow
prevails. Freezing temperatures are expected Tuesday night and
Wednesday night. At this time, a freeze warning has not been issued
for Tuesday night as guidance shows persistent overnight clouds over
parts of the area. This leads to lower confidence for a widespread
freeze and will hold off on a freeze warning for now.
For the latter half of the work week and into the weekend, the upper
low will slowly exit to the NE allowing for broad ridging to move
in. Look for temperatures to steadily warm as S/SW flow increases.
This may result in additional fire weather concerns late week and
will need to be monitored. Highs will likely reach the 70s by
Saturday. Expect mostly quiet weather with no significant upper
level features moving through the region. A weak shortwave could
move through late Saturday into Sunday, but no impacts other than
increased cloud cover are anticipated.
An upper trough will approach the region late Monday. Expect
increasing rain chances as large scale ascent and moisture advection
increases. Model disagreement leads to high uncertainty but chance
POPs are reasonable at this time.
&&
.Aviation...(00Z TAF Issuance)
Issued at 729 PM EDT Mon Oct 17 2022
Impacts:
*Winds from 300-320 degrees with gusts to 20-25 kts through at
least 9z tonight...and only slightly lower into Tuesday morning
*MVFR possible in scattered rain/snow showers 02z-08z at KLAF/KIND
Discussion:
Tight surface gradient will continue into Tuesday morning with
central Indiana positioned between stacked low over Lake Huron and
broad surface high pressure slowly arriving from south-central
Canada. Fresh northwest winds with gusts to 20-25 knots will
continue tonight before diminishing slightly after 9z.
The fetch of BKN/OVC stratocumulus off of southern Lake Michigan
should remain at mainly VFR decks. Several hours of isolated to
scattered rain/snow showers through the middle of the overnight may
bring MVFR CIGs at times to KIND/KLAF terminals. Blustery
conditions are expected to continue Tuesday, with gusts increasing
to 20-25 kts during 16z-00z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 10 AM EDT Tuesday for INZ021-028>031-
035>049-051>057-060>065-067>072.
&&
$$
Update...BRB
Short Term...MK
Long Term...Melo
Aviation...AGM
...UPDATED AVIATION FORECAST DISCUSSION...
.SHORT TERM...(This evening through Tuesday night)
Issued at 317 PM CDT Mon Oct 17 2022
The RAP and HRRR models indicate the swath of clouds across the
Dakotas this afternoon will move due south through much of wrn and
ncntl Nebraska tonight. The low temperature forecast tonight leans
on the short term model blend plus 3 degrees for lows mostly in the
20s. This could still be too cold given the models show temperatures
rising as the cloud cover thickens after midnight. This forecast is
several degrees warmer than the guidance blend and close to the 75th
percentile of the NBM.
1034mb high pressure across Manitoba this afternoon will move due
south and be located across OK Wednesday morning. The ridge is very
narrow east and west and this should present south and west winds
across wrn Nebraska and calm winds across ncntl Nebraska Tuesday
night. Temperatures aloft at h850mb will be warming aloft; close to
10C by Wednesday morning. The temperature forecast leans on the
warmer short term model blend for lows in the 20s. This forecast is
also several degrees warmer than the guidance blend and close to the
75th percentile of the NBM.
There is little change in the temperature forecast Tuesday. The cold
air advection is neutral and there is a chance the mid level
cloudiness shown in the RAP model will affect the heating cycle.
Highs in the 40s and 50s are in place with generally clear skies.
This is close to the NBM 50th, slightly warmer than the guidance
blend, but not as warm as the RAP or HRRR models.
.LONG TERM...(Wednesday through Monday)
Issued at 317 PM CDT Mon Oct 17 2022
The ECM and GFS continue to advertise a fairly deep trof
moving through the northern states this weekend and then into the
nrn Plains and srn Canada Monday. This would result in a strong
Pacific cold front sweeping into Nebraska Sunday. Today`s runs are a
bit slower with this front, so temperatures in the 70s are predicted
Wednesday through Saturday with a split between 60s across wrn
Nebraska and 70s across cntl Nebraska Sunday.
It is noteworthy the GFS and ECM deepen the storm to 974-981mb
across Manitoba-wrn Ontario Monday and this could lead to a period
of strong west winds across wrn and ncntl Nebraska. High wind
criteria would appear to be more likely across the Dakotas.
POPs get a boost to 30-40 percent Sunday. This is probably warranted
given the caliber of the moisture return and height falls as the
upper low tilts northeast through the nrn Plains. The best moisture
advection will be well to the east, across the Midwest, and our rain
chances are a result of moisture carried across the nrn Rockies with
the Pacific front.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 615 PM CDT Mon Oct 17 2022
VFR conditions expected to prevail through tomorrow evening. Mid-
level clouds filter into the area through early tomorrow
afternoon, though CIGs remain well into VFR. Winds remain light
from the north, primarily below 10kts.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Brown
Area Forecast Discussion
National Weather Service Louisville KY
956 PM EDT Mon Oct 17 2022
.Forecast Update...
Issued at 956 PM EDT Mon Oct 17 2022
A chilly, breezy night continues across the middle Ohio Valley.
Kentucky Mesonet is showing temperatures already down into the
middle/upper 30s in many spots with dew points in the low/mid 20s.
The air temps are around a degree colder than what the going
forecast is showing, however with incoming clouds will refrain from
lowering MaxT. Temperatures upstream under the overcast are only a
few degrees cooler than what we are seeing down here to the south.
Latest guidance still supports lows generally in the upper 20s and
lower 30s for most.
The cloud shield to our north is quite expansive from the Great
Lakes all the way west to the Mississippi and south to the Ohio. Did
go ahead and increase cloud cover slightly for the next several
hours. Impressive streamers are coming off of Lake Michigan (there
was a recent public report of nearly 4" of snow in Whitley County,
Indiana) with radar showing reflectivities making it as far south as
the Kentucky side of the Cincinnati Metro. There have been a few
mPING reports of flurries with the reflectivities across southeast
Indiana and southwest Ohio. IND and ILN have received reports of
frozen precipitation, sometimes mixed with liquid, in these areas
with temperatures in the upper 30s and lower 40s. So, it still looks
good for getting a few flurries tonight, especially from southeast
Indiana into the Kentucky Bluegrass region. The HRRR has a decent
handle on this and gives the best flurry chances between 2am and 8am
EDT.
&&
.Short Term...(This evening through Tuesday)
Issued at 300 PM EDT Mon Oct 17 2022
...First Widespread Freeze of the Season Tonight...
...Scattered Snow Flurries Early Tuesday Morning...
Large anomalous upper low spinning around the Great Lakes region
today will not move much during the short-term period. Short wave
troughs spinning around that system will send waves of cloud cover
across our area, one in southern IN and northern KY this hour and
then a deeper moisture field coming in later tonight. Forecast
soundings from the hi-res models indicate the top of that layer into
the dendritic growth zone, so ice crystal formation is likely. The
question will be if and how much of those crystals survive to the
surface. There will be some dry air near the surface to
overcome...and those soundings as well as rh fields in time height
sections are not showing much near the surface. Thus will continue
the ongoing forecast for scattered non-impactful snow flurries early
in the morning hours.
The temperature forecast for tonight will hinge quite a bit on the
cloud cover overnight. Cold air advection with steady northwest
winds will continue through the night, but the thicker cloud cover
will act as a blanket, possibly preventing those areas from hitting
freeze warning criteria, 30 degrees or less for 2 hours or more.
Current forecast for lows is right in the middle of the model
guidance envelope. Those models indicate our northeastern counties
having the LEAST chance of reaching that criteria...along and north
of a line from Shepherdsville east to the Lexington area. Given that
forecast lows in that region are right around freezing, will not
pull the ongoing Freeze Warning at this point...but wouldn`t be
surprised if we have to issue a second headline across portions of
the Louisville forecast area for freezing conditions Tuesday
night/Wednesday morning. Points west of Louisville and south of that
Shepherdsville to Lexington line should end up getting cold enough
to stop headlines for the rest of the fall and winter seasons...but
we can make that decision tomorrow.
Cold air advection will continue with breezy conditions from the
northwest Tuesday, as again, that persistent and slow-moving upper
low continues to our northwest. Expect highs Tuesday some 20 degrees
below climatology.
.Long Term...(Tuesday night through Monday)
Issued at 300 PM EDT Mon Oct 17 2022
...NEAR RECORD LOWS POSSIBLE WEDNESDAY AND THURSDAY MORNING...
...CONTINUED DRY AND WARMER WEATHER THROUGH THE WEEK...
...NEXT CHANCE OF RAIN LIKELY EARLY NEXT WEEK...
====================================
Synoptic Overview
====================================
Very anomalous upper level low over the Great Lakes is forecast to
spin slowly across the Great Lakes early in the period. By mid-late
week, the upper low is forecast to lift northward into Quebec and
into an open wave. Deep cyclonic flow will remain in place across
the Ohio Valley through Thursday with the flow becoming a bit more
zonal by Friday. Dry and warmer conditions are expected through the
weekend as the flow across the CONUS becomes more progressive. The
next shortwave trough axis may impact the region by Monday bringing
a chance of much need precipitation to the area.
====================================
Meteorological Discussion
====================================
A highly amplified upper level pattern will be in place at the start
of the period (Tuesday night) with a large closed upper low over
western Ontario and a sharp trough axis extending southward through
the Ohio Valley. The pressure gradient looks to be a bit more
relaxed Tuesday night which may result in more optimal radiational
cooling. However, there is a chance that some stubborn low-level
stratus may remain in place across our far northeastern areas. We
did consider a Freeze Warning for Tuesday night, but the surrounding
office consensus was to hold off for now and see how tonight`s freeze
warning pans out. The expected lows Tuesday night will be near
record lows for October 19th. Sunny and dry conditions are expected
for Wednesday with highs in the low-mid 50s. Lows will likely drop
back into the mid-upper 20s Thursday morning which also may
tie/break record lows for October 20th. Highs on Thursday will be a
bit warmer with readings in the upper 50s to the near 60.
For Friday and into the weekend, the upper level low is forecast to
lift northward and become an open wave as it moves northward into
Quebec. The persistent trough axis through the Ohio Valley is
forecast to exit to the east and the flow across our area will
become more zonal and progressive through the weekend. Dry weather
is expected with a continued moderation in temperatures. Highs on
Friday will warm into the upper 60s to the lower 70s with lower to
mid 70s for Saturday and Sunday.
Moving into next week, a shortwave trough axis is forecast to move
toward the Ohio Valley. Signal analysis over the last week has been
doing fairly well at tracking this feature. The front associated
with this feature may bring a welcome chance of showers and
thunderstorms to the region as it passes through. For now, plan on
at least carrying a 30 PoP in that period. Highs Monday will
continue to be mild with low-mid 70s expected.
====================================
Societal Impacts
====================================
Cold overnight temperatures are expected Wednesday and Thursday
morning. The overnight forecast lows will be near record readings
for those dates. Continued dry weather and dry ground fuels will
lead to a continued elevated fire weather risk across the region.
====================================
Forecast Confidence
====================================
Forecast confidence on temperatures is medium to high, while
forecast confidence on precipitation is high.
&&
.Aviation...(00Z TAF Issuance)
Issued at 714 PM EDT Mon Oct 17 2022
MAIN IMPACT: Gusty winds Tuesday. MVFR stratus and brief flurries 06-
12Z Tuesday for LEX and possibly SDF.
DISCUSSION: A large upper low centered over the Great Lakes but
affecting most of the eastern half of the United States will be the
dominant weather feature during this TAF period. Large shield of
stratocu spiraling around the low will affect the terminals, and
will likely bring MVFR ceilings to LEX late tonight into early
Tuesday morning. SDF looks to be right on the edge of the sub-VFR
clouds.
With a tight gradient between the surface low to our north and high
pressure along the length of the Great Plains we can expect a gusty
WNW breeze tomorrow, to around 20-25kt.
CONFIDENCE: Moderate to high in MVFR ceiling potential for LEX early
Tuesday...lower for MVFR ceiling at SDF. High confidence in winds.
&&
.Climate...
Updated at 300 PM EDT Mon Oct 17 2022
================== Near-Record Low Temperatures ==================
Tuesday Wednesday
(Fcst/Record) (Fcst/Record)
Louisville: 36/25 (1948) 35/30 (1948)
Bowling Green: 31/27 (1948) 29/28 (1903)
Lexington: 32/24 (1948) 31/26 (1992)
Frankfort: 32/25 (1988) 30/27 (1992)
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Freeze Warning from 10 PM Monday to 10 AM EDT Tuesday for
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
IN...Freeze Warning from 10 PM Monday to 10 AM EDT Tuesday for
INZ076>079-083-084-089>092.
&&
$$
Update...13
Short Term...RJS
Long Term...MJ
Aviation...13
Climate...RJS/MJ
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1004 PM CDT Mon Oct 17 2022
.UPDATE...
Issued at 1004 PM CDT Mon Oct 17 2022
Cancelled the Winter Weather Advisory for Porter and Jasper
counties in northwest Indiana overnight, as best focus for any
travel impacts from accumulating lake effect snow looks to remain
east of the forecast area. Otherwise, forecast is generally on
track with light snow showers and flurries generally decreasing in
coverage late this evening west and southwest of Lake Michigan.
Regional radar coverage since mid-afternoon has depicted the
primary lake convergent axis along the eastern shore of Lake
Michigan, with associated heavier lake effect precipitation
focused mainly across far southwest lower Michigan and north
central Indiana. High-res CAM guidance indicates this trend will
continue over the next several hours, with the probability of
travel impacts associated with any accumulating snow over Porter
and Jasper counties continuing to diminish. Based on this, and
being past the evening heavier travel period, have elected to
cancel the winter weather advisory for those counties. Less
organized rain/snow showers will likely affect northwest Indiana
into the overnight hours, though with no significant accumulations
expected.
Elsewhere, scattered snow showers which were associated with an
earlier mid-level short wave have diminished/dissipated across
northern IL and parts of the IL/IN state line region. A few
flurries may linger at times into the overnight hours. Blustery
northwest winds will persist with gusts of 25 to 30 mph at times,
and up to 40 mph along the immediate Indiana lakeshore. With
strong northerly winds persisting, have made no changes to current
Lakeshore Flood Advisory which continues through Tuesday.
Updated products available.
Ratzer
&&
.SHORT TERM...
Issued at 330 PM CDT Mon Oct 17 2022
Through Tuesday...
The primary forecast messages through Tuesday are:
* Continued well below normal temperatures in blustery conditions,
with gusts up to 30 to 35 mph, and near the Indiana lake shore
of 45 to 50 mph
* Flurries with spotty snow showers through this evening, with
focus turning to downstream areas in northwest Indiana of Lake
Michigan by mid-evening; still high uncertainty whether there
will be snow accumulation of impact and the potential for that
has diminished since early this morning -- if trend continues
the Winter Weather Advisory will be cancelled early
* Minor lakeshore flooding along the northwest Indiana shore
through Tuesday; possible some minor lakeshore flooding or at
least spray on parts of the Cook County shore
The substantial long wave trough across eastern North America is
well defined today, with a broad but very well-defined closed
circulation center over the Great Lakes. The 500 mb temperatures
with this center are around -35C, which are at record cold for
October using GRB sounding climatology. Numerous vorticity maxima
within this upper trough have provided isolated pockets of ascent
and deeper saturation for showers, which have been primarily snow
showers in our forecast area. Some of these have produced brief
"snow globe" behavior with ~1 SM visibility underneath them,
including even in the far western forecast area (near Rock Falls
and Rochelle). The next wave for northern Illinois is less-defined
and a little more sheared than its predecessor, and this will
swing southward from Wisconsin by early to mid evening. This is
forecast to increase snow shower chances, including for Chicago.
Due to limited saturation depth above -10C per aircraft soundings,
and overall limited low-level focus to drive stronger shower
updrafts, the quality of the snow with any of these showers should
not be great in northern Illinois. Also the quick forward
progression should be enough to limit any accumulations. Flurries
and snow showers should taper from northwest to southeast across
northern Illinois during the later evening.
For northwest Indiana (downstream of the lake), disorganized lake
effect snow showers look to be the primary mode, apart from a
window of time mid-evening into early overnight when a more
concentrated, mesoscale-influenced focus could set up. This
potential though is lessening as convergence is presently along
the Michigan shore per observations -- that`s quite possibly too
far east for a focus in our CWA. This is forecast by CAMs to
wobble some, including slightly westward, with growing instability
of lake-induced CAPE > 800 to as much as ~1,500 J/kg along the
Porter County shore (modifying forecast soundings for lake temps
and current dew points over the water). The next mid-level wave
over northern lower Michigan does look to sharpen the convergence
over eastern Lake Michigan through the evening, but whether or not
a well-defined wave such as multiple earlier runs of the HRRR
showed, is uncertain. If so, it would support brief periods of
heavier snow showers. But if trends continue as such for another
few hours, the evening shift likely will be able to cancel this
impact-based Advisory early.
As for winds and waves...the surface low depth is down to 997 mb
over Lake Huron and will continue to gradually deepen through
tonight before holding steady on Tuesday, and all at the same time
with little movement. The locked-in cyclonic flow pattern will
support continued cold air advection mixing and a pressure
gradient that will keep gustiness tonight through Tuesday. Over
the lake, there have been marine platform observations of 45 to 50
mph (50 at St. Joseph, Michigan), so the going Wind Advisory for
lakeside Indiana areas looks good. Did extend it some during the
day tomorrow and may need to go through the entire afternoon. The
building waves from these winds have already been up to 9.5 feet
at Michigan City, IN, and per wave model guidance utilizing
forecast winds, these should get solidly be into the 10 to 15 ft
area, especially for Porter County, tonight and Tuesday.
Otherwise, clouds should show some thinning in western parts of
the CWA late this evening, though how quickly is of low
confidence. The thicker the clouds, the more the temperatures may
hold up. Still expecting most of northern Illinois apart from
downtown Chicago to drop to freezing or below. Do note that we at
NWS Chicago have collaboratively ended our growing season
products as of today, so no more Frost/Freeze headlines will be
issued this autumn.
Tuesday`s precipitation focus will be Porter County, Indiana and
eastward, with lake effect showers or flurries of a disorganized
nature probable to continue. These should be light enough for
little to no snow accumulation due to a lack of strong
convergence and associated deeper updrafts. Inland, stratocumulus
clouds are expected, and cannot rule out sprinkles with these.
MTF
&&
.LONG TERM...
Issued at 330 PM CDT Mon Oct 17 2022
Tuesday night through Sunday...
Main weather features of interest are:
- Upper Low and associated trof continue to spin across eastern
Canada, holding the colder temperatures in place through mid-week.
- Low ejects out of the area during second half of week, bringing a
return to warmer temperatures to end the week through the weekend.
- Zonal flow arrives Friday, ridging into the weekend, when
temperatures are forecast to climb back to the 60s and 70s.
- Next chance for precip arrives to end the weekend, as another Low
pressure system and trof takes hold over the northern Plains and
upper Midwest.
Precip chances will be coming to an end Tuesday night across
northwestern Indiana as the sfc Low lifts slowly ENE through the
eastern Great Lakes into Canada. Temperatures moderate into mid-
week, as a weak zonal flow system sets up. As the upper Low ejects
out of the Great Lakes Thursday, southwesterly winds return across
the central Plains into the Midwest to end the work week. A ridge of
High pressure dominates the weather pattern Friday through much of
the weekend, where southerly winds bring another rise in
temperatures back to the 60s and low 70s. Ahead of the next weather
producing system, southerly winds ramp up Sunday with models
bringing 20-30mph gusts. Another Low pressure system tracks through
the northern Plains late Sunday into Monday, swinging a trailing
frontal boundary through the area...bringing the next chance of
rainfall to the region.
SB
&&
.CLIMATE...
Last updated at 315 PM CDT Mon Oct 17 2022
Here are the current records in place for today and Tuesday. Note
Chicago (O`Hare) has reached at least 41 so today will not be a
record.
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)
&&
.AVIATION...
For the 00Z TAFs...
Forecast concerns for the terminals...
*Gusty northwest winds persisting through Tuesday evening
*Occasional MVFR clouds this evening through Tuesday morning
*Chance for lake effect showers at GYY this evening
A deep upper-level trough continues to reside over the Great Lakes
region which is helping to maintain the gusty northwest winds
currently being observed across the area. Winds are expected to
ease a tad late this evening, but gusts will still remain in the
upper 20 to around 30 kt range through Tuesday evening. As the
trough begins to move east Tuesday evening gusts are expected to
ease to around 20 kts overnight Tuesday night into Wednesday.
In addition to the winds, there will also be a chance for a few
flurries across northeastern Illinois this evening with more
robust lake effect showers in northwest Indiana. Aircraft and
forecast soundings have continued to show that the snow growth
region has struggled to saturate which has limited more robust
snow showers developing as previously forecast. However, there has
been just enough moisture in the snow growth region to promote
occasional flurries as noted in recent radar and observational
trends therefore I have maintained the VCSH mention at the
Illinois sites to account for this potential. These flurries are
expected to come to an end this late this evening as drier air
filters in aloft. More robust lake effect showers have continued
to be observed across northwestern Indiana and the open waters of
Lake Michigan where soundings have shown much better saturation in
the snow growth region. While most sites along the immediate lake
shore have reported more of a rain-snow mix the thinking is that
most areas should transition over to all snow as surface
temperatures cool this evening. For that reason I have continued
the TEMPO for -SHSN at GYY to account for this potential through
late evening.
Lastly, there is also the possibility for occasional MVFR ceilings
through Tuesday morning especially in areas that experience any
showers. Otherwise VFR conditions are expected to prevail through
the TAF period with ceilings gradually scattering out Tuesday
evening.
Yack
&&
.MARINE...
Issued at 649 AM CDT Mon Oct 17 2022
Northwest gales are expected through Tuesday. The strongest gales
to 40 knots (briefly to 45 knots in the Indiana nearshore) are
expected this evening as a trough shifts across Lake Michigan.
Winds will only slowly diminish through the day Tuesday, with some
gale gusts to 35 knots remaining possible into Tuesday evening.
Kluber
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...Lakeshore Flood Advisory...INZ001 until 10 PM Tuesday.
Wind Advisory...INZ001-INZ002 until 1 PM Tuesday.
Lakeshore Flood Advisory...INZ002 until 4 AM Wednesday.
LM...Gale Warning...nearshore waters until 10 PM Tuesday.
&&
$$
Visit us at weather.gov/chicago
Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/NWSChicago
www.twitter.com/NWSChicago
www.youtube.com/NWSChicago
Area Forecast Discussion
National Weather Service Marquette MI
754 PM EDT Mon Oct 17 2022
.SHORT TERM...(This evening through Tuesday)
Issued at 410 PM EDT MON OCT 17 2022
...Heavy wet snow will continue into Tuesday over the higher
terrain, especially north central...
Water vapor imagery and RAP analysis continue to show an amplified
pattern across N America. Strong ridges over western N America and
also the N Atlantic, extending across Greenland, are locking in a
deepening trof from the Canadian Arctic across Hudson Bay into the
Great Lakes region. 130+ kt upper jet axis extending s fm
Manitoba/NW Ontario into MN and associated shortwave are currently
working to amplify the trof, and have closed off a fairly stacked
mid-level low over Lake Huron today. Cyclonic northerly flow, CAA
and weak forcing around the closed low are combining to support lake
enhanced snow showers into mainly the north central UP this
afternoon. Q-vector divergence and associated subsidence has worked
to taper off the lake effect snow over the western counties so have
allowed the warnings to expire over Gogebic and Ontonagon counties
and the warning and advisory will be allowed to expire over Northern
Houghton and Keweenaw counties respectively by early evening.
Will keep WSW and Lakeshore Flood headlines going for central and
eastern counties of the cwa tonight into Tuesday as models show
continued strong cyclonic northerly flow and continued enhancement
potential as another shortwave is fcst to rotate back around the
closed low and into the eastern half of the cwa late tonight into
Tuesday. With ptype already changed over to mostly snow in Baraga
and Marquette counties away from Lake Superior, I`m fairly confident
in snow piling up over the higher terrain tonight into early
Tuesday. Generally have anywhere from 4 to 10 inches over the higher
terrain with more than a foot of additional snow possible from the
Michigamme Highlands into the Huron Mountains. Will keep winter
weather advisories going into Iron County this evening and into
Dickinson County overnight although most additional snow
accumulation will be confined to the far northern portions of these
counties. In the eastern counties, ultimately decided to upgrade the
watch to an winter weather advisory tonight into Tuesday since
warmer air initially off Lake Superior will cut into the snow
amounts so basicaly have amounts anywhere from 1 to locally 5-6
inches, highest over western Alger and northwest Delta counties.
Also, northerly winds will likely gust to advisory criteria (45-50
mph) or higher at times so incorporated this wording into the WSW
advisory statement.
Lakeshore flood advisories and warnings will be continued into
Tuesday and Tuesday evening as winds increasing from high-end gales
to Storms will continue to build pounding waves near the lakeshore
areas.
.LONG TERM...(Tuesday night through Monday)
Issued at 310 PM EDT MON OCT 17 2022
Upper air pattern will consist of a closed 500 mb low over the lower
Great Lakes 00z Wed with a ridge in the western U.S. The closed low
meanders over the lower Great Lakes and then moves to western Quebec
by 00z Fri while the ridge in the western U.S. weakens and
retrogrades back to the west. With the storm system off to the east
of the area, lake enhanced pcpn will slowly move out and will switch
over to pure lake effect pcpn. Did put in some pops into the
forecast for the west and north due to lake effect possibilities as
models looked to be too dry with north winds continuing across the
warm waters of Lake Superior and continued them through Wed night.
This was the main change to the going forecast.
In the extended, the GFS and ECMWF show a 500 mb trough on the east
coast with a trough in the upper Great Lakes and one off the sw CA
coast 12z Fri. Another trough moves into the Pacific NW 12z Sat
which moves into the Rockies 12z Sun and into the upper Great Lakes
12z Mon. Temperatures go above normal for this forecast period and
will be warm enough that the pcpn will be rain. Could be windy late
this weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 754 PM EDT MON OCT 17 2022
Poor flying conditions will continue through this TAF period as snow
showers persist along with lake enhancement behind the closed low.
So, this means MVFR conditions with periods of IFR at times for all
TAF sites. In addition, the strong northwest winds will continue to
be an impact with sustained speeds in the 23 to 26 kt range, gusting
to 40 kts at KCMX and KSAW. At KIWD, winds will be just a bit
lighter with sustained speeds in the 12 to 14 kt range and gusts to
25 kts. In addition, LLWS will impact KSAW tonight through tomorrow
afternoon with gusts up to 50 kts under 2000 feet.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 310 PM EDT MON OCT 17 2022
Strong autumn storm will continue to bring strong north gales of 45
knots and storm force winds to 55 knots to Lake Superior into Tue
evening before the wind diminishes below gales. The wind gets below
20 knots by Thu morning and then increases to 20 to 25 knots on Fri
from the sw.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Lakeshore Flood Advisory until 10 PM EDT Tuesday for MIZ001.
Winter Weather Advisory until 8 PM EDT this evening for MIZ001.
Lakeshore Flood Advisory until 2 PM EDT Tuesday for MIZ002-003.
Winter Storm Warning until 8 PM EDT this evening for MIZ003.
Winter Storm Warning until 8 PM EDT Tuesday for MIZ004-005.
Lakeshore Flood Warning until 2 AM EDT Wednesday for MIZ005>007.
Winter Weather Advisory until 8 PM EDT Tuesday for MIZ006-007-
085.
Winter Weather Advisory until 2 AM EDT Tuesday for MIZ010.
Winter Weather Advisory until 8 AM EDT Tuesday for MIZ011.
Winter Weather Advisory until noon EDT Tuesday for MIZ013-014.
Lake Superior...
Gale Warning until 11 PM EDT this evening for LSZ162.
Gale Warning until 8 PM EDT Tuesday for LSZ240>242-246-247-263.
Storm Warning until 11 AM EDT Tuesday for LSZ243>245-248-264-265.
Gale Warning from 11 AM Tuesday to 2 AM EDT Wednesday for
LSZ243>245-248-264-265.
Storm Warning until 4 PM EDT Tuesday for LSZ249>251-266-267.
Gale Warning from 4 PM Tuesday to 5 AM EDT Wednesday for
LSZ249>251-266-267.
Lake Michigan...
Gale Warning until 2 AM EDT Tuesday for LMZ221-248-250.
Storm Warning from 2 AM to 5 PM EDT Tuesday for LMZ221-248-250.
&&
$$
SHORT TERM...Voss
LONG TERM...07
AVIATION...TDUD
MARINE...07