Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/06/22
Area Forecast Discussion
National Weather Service Boston/Norton MA
1026 PM EST Wed Jan 5 2022
.SYNOPSIS...
Periods of rain are expected this afternoon before a cold front
crosses the area tonight. Dry and colder weather returns
Thursday. Snow is expected late Thursday night into Friday as
low pressure passes southeast of New England. After a dry and
cold day Saturday, some light rain, with a light wintry mix
inland, is expected Sunday. A shot of arctic air should follow
early next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
No major changes to the overall forecast this evening. The
latest few runs of the HRRR and the NationalBlend had a good
handle on the timing of rainfall moving offshore from the Cape
and islands.
Besides the rainfall, the other concern overnight will be the
patchy dense fog across portions of western MA and northern CT.
Given the spotty nature of this fog, will continue to handle it
with a Special Weather Statement through midnight. Latest
guidance continues to suggest the fog will be lifting after
midnight as drier air arrives.
Minor tweaks to temperatures and dew points to reflect observed
trends.
700 PM Update:
Made some tweaks to PoPs/Wx to match current conditions and
expected near-term trends.
Frontal rains continue to shift offshore, now primarily
affecting Cape Cod and the Islands. Some brief downpours
possible in some of these steadier rains thru 10 PM before
moving further seaward.
In the post-frontal air mass, clearing and drying appears to be
delayed with continued SW flow. Noting observations in the CT
Valley in the Springfield and Hartford metros that pooled,
trapped shallow moisture and lack of mixing is leading to areas
of patchy fog, in some instances of the locally dense type. RAP
soundings indicate fog may not lift until late tonight
(as late as midnight?). May opt to issue an SPS if conditions
do not improve.
While skies should clear out, dewpoints will be slower to fall
limiting evaporation potential. Any standing water on roads
could re-freeze into black ice as temperatures especially in
interior MA/CT fall below freezing. See the SPS sent earlier.
Lows still look on track with mid/upper 20s to near 30 in the
interior NW of I-95, and the mid to upper 30s eastern MA and
eastern/coastal RI.
Previous discussion:
Mesonet observations show temperatures have risen above freezing
across interior so the Winter Weather Advisory was allowed to
expire. Expect periods of rain through afternoon per latest
radar trends. Temperatures have surged into lower 50s across
parts of E MA and RI due to increasing southerly flow while
farther inland low level cold air remains entrenched with
temperatures in mid and upper 30s. Patchy fog will linger in
interior through this evening where mixing will be more limited.
Later tonight, cold front crosses SNE bringing wind shift to W
along with drier air into region. Expect at least partial
clearing overnight as temperatures fall back into the upper 20s
to mid 30s. Could be some spotty icing across interior due to
leftover standing water, especially since winds will be light,
so we are considering a Special Weather Statement to highlight
this concern.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
Updated 1245 PM Wed
High pressure builds over SNE Thu. Should be enough mixing for
some 20-25 mph gusts, mainly near coast, otherwise expect plenty
of sunshine until clouds begin to increase during afternoon
ahead of our next system. Highs will top out in 30s and lower
40s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Highlights...
* Coastal low-pressure system to bring accumulating snow to
Southern New England very late Thurs into Fri. Heavy snow
possible particularly I-95 Boston to Providence corridor into
Southeast MA. Significant impact to the AM commute.
* Milder Sun with a period of light wintry mix interior and
generally light rain showers along the coastal plain.
* Arctic outbreak possible later Mon into Tue.
Details:
Thursday Night into Friday:
* Winter Storm Watch issued for the Boston-Providence I-95 corridor
to the South Coast of RI/MA. Increasing concern for heavy snow to
impact Friday morning`s commute, with very difficult travel more
likely in the Watch area.
We continue to monitor details regarding a potential winter storm
that is likely to bring accumulating snow for much of Southern New
England later Thursday night into Friday.
There remains uncertainty on the storm`s eventual track. Most of the
deterministic and ensembles/their members are close to the 40N/70W
benchmark. But there still remain a good deal of spread with some
tracking over the benchmark and others more southeast. Heights at
700 and 850 mb are also open-wave, reflecting a more progressive,
quick-hit system.
Snow should begin to break out around or just after midnight in
western MA/CT, then into the pre-dawn Friday hrs for the rest of
Southern New England. Period of greatest snow accumulation is
centered around the early to late-morning hrs with likelihood of
difficult travel during the AM commute. We then should see clearing
take place from west to east through early to mid afternoon. Lighter
if any additional new snow for the PM commute.
Storm total QPF amounts, heavily utilizing WPC`s QPF, range from a
quarter-inch to a third of an inch for northern and western MA into
CT, between a third to a half-inch into Middlesex and Worcester
Counties, and half to two-thirds of an inch across the I-95 Boston-
Providence corridor SE to Cape Cod and the Islands (where rain will
mix in).
This has the look of an Advisory-level event for most of Southern
New England with updated snow amounts ranging from 2-4 inches from
the Berkshires to the CT Valley, a general 3-5 inches with potential
for 6 inches across eastern CT, Worcester County northeast into
northern Middlesex and the North Shore; have 4-6 inches with
potential for local higher amts across the I-95 corridor in RI/MA
into southeastern MA. While it is not well agreed upon, and it is
possible that banding could extend further back N/W than current
indications if a closer-to-the-benchmark track ensues, but there is
some consensus on bands of locally heavy snow during the Friday AM
commute along the I-95 corridor. Even the more offshore NAM solution
shows about 20 microbars of lift in the snow-growth region between
09-15z, with the GFS/ECMWF showing similar but augmenting that with
fairly robust 850-700 mb frontogenesis across eastern MA/RI.
Certainly seen the influence and impact heavy snow on roads can
cause over the last few days, and thus have opted to issue a more
impact-based Winter Storm Watch from 1 AM to 1 PM Friday across the
Boston-Providence I-95 corridor into southeast MA. It is in this
area that we feel reasonably confident on heavy snow impacting the
AM commute where snow rates could be as much as 1 inch per hr and
possible local whiteout conditions. However given the continued
uncertainty in storm track, it is possible this area of heavy snow
and potential banding could shift NW or SE of the I-95 area.
Friday Night into Early Next Week:
Focus was mostly on the winter storm, and didn`t make significant
alterations over NBM in much of this period. Couple systems to
contend with, with temperatures generally below average.
Large high pres settles in to Southern New England on Friday night
into Saturday. Should have a period of drier weather with decreasing
NW winds Friday night. Exactly how cold we get will hinge on winds
diminishing to light. Temps below-normal.
Warm up towards later Saturday into Saturday night, though a frontal
system looks to bring another snow to rain mix to the interior on
Sunday. Temps Sunday trend above normal around the lower 40s.
Temperatures then take the Arctic plunge behind this frontal
system as a surge of Arctic air looks to move across New
England. Core of the cold is centered on Tuesday where highs may
only reach the teens to lower 20s with NW breezes to boot.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight: Moderate confidence.
Generally MVFR-VFR across the coastal plain, with improvement to
VFR expected overnight. For the western airports, fog with local
LIFR-VLIFR conditions across the CT Valley airports. May be
tough to see much improvement until about 04-05Z. Thus, better
odds for all-VFR after 06z but the timing could still slip by an
hour or two.
Light SW winds in the interior; SW winds around 8-12 kt for BOS,
PVD and Cape airports where gusts up to 25 kt should continue.
Thursday into Thursday Night: High confidence.
VFR Thu before conditions deteriorate to MVFR/IFR in snow from
west to east late Thu night.
KBOS Terminal...Moderate confidence in TAF.
KBDL Terminal...Moderate confidence in TAF.
Outlook /Thursday Night through Monday/...
Thursday Night: Mainly VFR, with areas IFR possible. Breezy. SN
likely.
Friday: MVFR/IFR conditions possible. Windy with gusts up to
35 kt. Chance SN.
Friday Night: VFR. Windy with areas of gusts up to 35 kt.
Saturday: VFR. Breezy.
Saturday Night: Mainly VFR, with local IFR possible. Breezy.
Chance SN.
Sunday: MVFR/IFR conditions possible. Breezy. RA likely, chance
SN.
Sunday Night: MVFR/IFR conditions possible. Breezy. Chance RA.
Monday: VFR. Breezy.
&&
.MARINE...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Keeping Gale Warnings and Small Craft Advisories as posted.
Strong southerly winds persist through early tonight before cold
front crosses waters overnight and causes diminishing winds and
a wind shift to W. Light rain and fog expected through early
tonight ahead of front.
W winds increase again Thu morning and we should see frequent
20-25kt gusts during day. Winds diminish Thu evening and veer to
N and then NE overnight, with snow arriving early Fri morning.
Outlook /Thursday Night through Monday/...
Thursday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Rain, snow.
Friday: Low risk for gale force winds with gusts up to 35 kt.
Local rough seas. Rain, chance of snow.
Friday Night: Strong winds with gusts up to 35 kt. Rough seas
up to 10 ft.
Saturday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas.
Saturday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Local visibility 1 to 3 nm.
Sunday: Strong winds with gusts up to 30 kt. Rough seas up to
10 ft. Rain likely.
Sunday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 10 ft. Chance of rain.
Monday: Moderate risk for Small Craft Advisory winds with gusts
up to 25 kt. Rough seas up to 10 ft. Slight chance of snow.
Local visibility 1 to 3 nm.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Winter Storm Watch from late Thursday night through Friday
afternoon for MAZ013>021.
RI...Winter Storm Watch from late Thursday night through Friday
afternoon for RIZ001>007.
MARINE...Small Craft Advisory until 10 PM EST Thursday for ANZ231-232-
250-254>256.
Small Craft Advisory until 1 PM EST Thursday for ANZ233-234-
251.
Small Craft Advisory until 7 AM EST Thursday for ANZ230-236.
Small Craft Advisory until 7 PM EST Thursday for ANZ235-237.
&&
$$
SYNOPSIS...Loconto/JWD
NEAR TERM...Belk/Loconto/JWD
SHORT TERM...JWD
LONG TERM...Loconto
AVIATION...Belk/Loconto/JWD
MARINE...Loconto/JWD
Area Forecast Discussion
National Weather Service Burlington VT
956 PM EST Wed Jan 5 2022
.SYNOPSIS...
An active period of weather will persist over the North Country
beginning tonight and continuing through early next week. Lake
effect snow will impact southern St Lawrence County tonight
into Thursday followed by chances for light accumulating snow on
Friday and Sunday. Monday will usher in a much colder airmass
with the threat for dangerous wind chills Monday night and
Tuesday.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 949 PM EST Wednesday...The development of enhanced lake
effect showers along a weak surface trough has struggled. Most
of the activity has been light and disorganized. RAP analysis
depicts a fragmented frontal feature, that is more evident to
our south. As such, lowered PoPs and QPF for the next several
hours. Conditions still appear favorable for enhanced lake
effect activity in the morning. With that, the Winter Weather
Advisory remains in effect beginning midnight through 7 PM
Thursday for the St Lawrence Valley. Yet, the greater impacts of
it will likely not be felt until the morning.
Previous Discussion...
Low pressure currently located over the northern tip of Michigan
will move out of the Great Lakes and into southern Quebec tonight.
Main impact will be the development of a persist lake effect band
across southern St Lawrence County tonight into Thursday. Before
this lake band develops, widely scatted snow showers will affect the
North Country as surface boundary moves through overnight (prior to
lake effect really developing). Accumulations should be limited to
around a dusting for areas across Vermont and up to one inch
possible for northern New York. Behind this boundary, winds will
turn out of the SW favoring the development of the aforementioned
lake effect band. Accumulations of 3 to 7 inches continues to look
likely for locations south of US Route 11 and especially south of NY
Route 3. HREF probabilities for 24-hr snowfall greater than 4" is
over 90% for areas south of NY Route 3, however probabilities for
greater than 8" remains mostly confined to the immediate areas
downwind of Lake Ontario over the Tug Hill. Snowfall rates within
the band could approach 1" per hour, although most guidance
indicates rates will be between 0.5-0.75"/hr. As surface low
pressure pull northeast towards the Gulf of St Lawrence Thursday,
winds will trend more westerly across the area pivoting this band of
snow south and out of the area. Some lingering snow showers will be
possible across the Adirondacks and northern Greens Thursday
night but accumulations should generally be an inch or less.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 328 PM EST Wednesday...Friday continues to look rather
uneventful for the North Country at this time. The latest ensemble
low tracks from WPC show a low pressure system quickly pushing
across the Mid-Atlantic and pushing east of benchmark late Friday
morning. This track is not favorable for our typical big snow events
but fear not as we should still see some light snow through the day
on Friday. Model soundings continue to show a saturated DGZ with
weak omega within the snow growth region which will support light
snow through much of the day Friday. The DGZ lowers through the day
following the passage of a cold front with temperatures falling
during the afternoon hours. This will yield higher snow rations
which may allow for some "fluff" across the region. When all is said
and done, we are looking at a dusting across northern New York all
the way to 1-2 inches of snow accumulation across southern and
eastern Vermont. Some slightly higher amounts are possible at summit
level with some backside bonus with nice upslope northwesterly flow
but the lack of moisture will be the limiting factor for snow totals
in this event.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 328 PM EST Wednesday...If you`re looking to enjoy the great
outdoors this weekend, Saturday is the day to do it. A 1036 mb
transient high pressure system will bring some period of sun to the
North Country although temperatures will hover on the cold side with
highs only climbing into the mid teens to lower 20s. Temperatures
will actually warm through the evening and overnight hours Saturday
into Sunday as we see strong return flow develop across the region.
Gusty winds, especially within the Champlain and St. Lawrence
Valleys will allow temperatures to warm into the mid to upper 30s by
Sunday afternoon. A strong arctic cold front will move through the
region on Sunday and bring a period of rain, sleet and snow.
Freezing rain no longer appears to be a concern as the warm nose
associated with a warm front likely stay at or below zero. Some re-
freezing of partially melted hydrometeors may yield isolated pockets
of sleet but generally snow or rain is expected on Sunday with the
p-type largely dependent on the surface and boundary layer
temperatures. Overall, only minor accumulations of snow are expected
with marginal surface temperatures and weak forcing.
The beginning of next week is shaping up to be some of the coldest
weather seen over the past several years as lows Monday night are
expected to plummet into the single digits and teens below zero.
Cloud cover will be a key to just how cold it`ll get across the
region with the NBM and other deterministic guidance showing partly
to mostly cloudy skies. Given 850 mb temperatures below -30 degrees
C, if we do see any kind of clearing, temperatures close to 20 below
cannot be ruled out. In addition to these colder temperatures, we
should see a steady 8-15 mph wind through the overnight hours Monday
into Tuesday morning. This will lead to wind chills values ranging
from -15 to -30 degrees. At these values, we consider this cold to
be dangerous with frostbite possible on exposed skin within 30
minutes. Tuesday doesn`t look much better with temperatures only
warming into the single digits above and below zero with a steady 5-
10 mph wind. These will keep wind chills in the double digits below
zero for much of the day Tuesday. By Tuesday night, we should
finally see winds begin to abate but will once again see temps in
the single to double digits below zero. Luckily for us, the pattern
this winter has been very progressive which means we will see a warm
up closer to seasonal values on Wednesday. Dry weather is expected
through the first half of next week.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Through 00z Friday...The next 24 hours will feature breezy winds
and occasional snow showers. Some intermittent LLWS will be
possible across a number of sites with 35 to 40 knot southwest
winds at 2000 ft agl for about the next 6 hours. Ceilings are
generally 5000-7000 ft agl at the moment. As lake effect snow
showers and a weak boundary shift east from 01Z to 05Z over
northern New York and 04Z to 10Z over Vermont, occasional
reductions towards MVFR ceilings and 2SM-6SM visibilities will
be likely, especially at SLK and EFK. Southwest winds are
expected to gradually increase from 5 to 12 knots up to 8 to 14
knots with gusts around 16 to 20 knots. Wind directions will
be wavering between 220 and 260 across the region the remainder
of the day. Some periodic lake effect snow showers will also
develop across SLK, with the best chances of additional activity
between about 12Z and 21Z. We should also see a gradual
reduction in ceilings after 15Z, lingering near 3000 ft agl.
Wind speeds abating after 21Z towards 5 knots.
Outlook...
Thursday Night: Mainly VFR, with areas MVFR possible. Chance SN.
Friday: Mainly MVFR and IFR, with areas VFR possible. Likely SN,
Scattered SHSN.
Friday Night: Mainly VFR, with local MVFR possible. Isolated
SHSN.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. Slight chance SHSN.
Sunday: Mainly MVFR and IFR, with areas VFR possible. Likely
SHRA, Likely SHSN.
Sunday Night: Mainly MVFR, with areas VFR possible. Chance SHSN,
Chance SHRA.
Monday: Mainly VFR, with local MVFR possible. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...Winter Weather Advisory until 7 PM EST Thursday for NYZ029-087.
&&
$$
SYNOPSIS...LaRocca
NEAR TERM...Haynes/LaRocca
SHORT TERM...Clay
LONG TERM...Clay
AVIATION...Haynes
Area Forecast Discussion...UPDATED
National Weather Service Peachtree City GA
1022 PM EST Wed Jan 5 2022
...Late Evening Update...
.UPDATE...
The forecast is on track with just minor tweaks being made to
near-term sky cover. A Winter Weather Advisory for far
northwestern Georgia is in effect from 7 AM to 7 PM Thursday,
while a second Winter Weather Advisory for the rest of our
northernmost counties is in effect from 3 PM to 11 PM Thursday.
Model soundings continue to suggest a rain/snow/sleet mix across
the advisory area, reinforcing the p-types currently in the grids.
The best shot at any freezing rain (which is still just a slight
chance) looks to occur during the early portion of Thursday
morning across the far northwestern CWA, given the presence of a
warm nose in the soundings across central TN and north-central AL,
as well as surface temperatures at or below freezing across our
far northwest area. That said, still expecting little to no
freezing rain accumulations.
Previous discussion on the winter weather potential is below.
Martin
&&
.PREV DISCUSSION... /Issued 722 PM EST Wed Jan 5 2022/
..Updated for 00Z Aviation Discussion...
PREV DISCUSSION... /Issued 251 PM EST Wed Jan 5 2022/
SHORT TERM /Tonight through Thursday Night/...
Weak surface boundary currently draped across northern Georgia.
Low pressure currently out in eastern Texas will move east today
along the front and is currently expected to move very close to
the I-85 corridor on Thursday. Areas north of where the front sets
up will have the potential for a mix of wintry precipitation,
especially far north Georgia.
Hi-res models are not quite in agreement with ptype for the far
northern portion of the CWA through thursday. The HRRR keeps ptype
mostly rain while the wrf-arw/nam high res models do produce some
wintry mix...potentially sleet or freezing rain for far NW
portions of the state. Some rain/snow mix is possible later
Thursday/Thursday night as the 500mb trough swings through
bringing some colder air aloft.
The forecast dilemma for NW Georgia will be the warm nose. Will
the warm nose be strong/deep enough for freezing rain or will
sleet be more likely? There is a distinct warm nose on the
soundings. The depth of the warm layer is is between 4-5kft. Not
much of a lifting mechanism at the onset of precipitation and the
best broad scale lift should be to the north of the CWA early
Thursday morning. But, some isentropic lift ahead of the main low
could produce some very light precip right around or just before
12Z...which the models are not very good at handling. Usually
start time is earlier than the model projections with
isentropically induced precipitation. Surface temps are expected
to be in the lower to middle 30s. So, best guess at ptype at this
time will be a rain/sleet mix with some slight potential for
freezing rain. Temps will remain in the 30s across NW GA for most
of the day tomorrow, and could be a little colder than forecast.
On the backside of the low pressure system, as the much colder air
aloft and at the surface moves in, and a change over from rain =>
snow is possible. There could also be a little sleet mixed in.
Will go ahead and issue a Winter Weather Advisory for portions of
north Georgia for tomorrow. Have segmented the advisory mainly
due to precip timing. The far NW corner may see some light wintry
precipitation closer to 12Z Thu with the NE segment having the
potential for wintry precip mainly in the afternoon and evening.
Overall, snowfall accumulations should be light and average less
than an inch. However, if sleet does end up mixing in, that will
undercut snow total values. Little to no accumulation of any
freezing rain is anticipated. However, wet elevated roadways may
develop patchy ice where temps hover in the lower to middle 30s
during the day Thursday.
Winds will shift to the NW behind the low pressure center and
become gusty. Frequent gusts to 20-25 kt will be likely. Not much
QPF is expected with the system, generally a third of an inch or
less, but soils remain fairly saturated.
This will be one of the coldest shots of air that we have had
this winter. Temperatures in the teens and 20s are anticipated
north of the I-85 corridor late Thursday night. Apparent
Temperature values in the single digits would necessitate the
issuance of a Wind Chill Advisory for portions of north Georgia.
NListemaa
LONG TERM /Friday through Wednesday/...
Not too many changes have been made to the long term forecast
since this mornings AFD. Temps will slowly rebound this weekend,
as the cold front clears the area. The weekend will see highs
rebound back into the 60s and maybe touching 70 across parts of
south/central GA as warm air advection surges out ahead of another
front set to move into the area Sunday night and into Monday.
This system looks like it will likely be a heavy rain producer,
with QPF values around 1.5 inches for most of northern GA with
locally higher amounts possible. While it`s still a ways out,
there isn`t any indication that a widespread surge in instability
is likely given the limited amount of time for warm air advection.
However current models are putting dewpoint values in the mid to
upper 50s south of the metro area so a rumble of thunder is
possible.
After the front passes, we`ll clear out with high pressure and
temperatures will return to around seasonal with highs in the low
50s and upper 40s and overnight lows hovering near 30.
Vaughn
AVIATION...
00Z Update...
Still some model disagreement in terms of cigs overnight and
tomorrow. Have MVFR cigs starting at 08z at ATL and other metro
sites with a TEMPO from 10z to 14z for BKN007. Have VCSH starting
at 15z at ATL, then -RA starting at 20z as a wave of rain moves
through. MVFR to IFR cigs should persist through the day with MVFR
vsbys (possibly even lower) at ATL and metro sites. -RA will end
across metro Atlanta by ~00z with -RA still possible at MCN and
CSG into the evening. In the wake of the rain late tomorrow
afternoon, winds will shift to W and then NW around 10-12 kts with
gusts around 20-22 kts.
//ATL Confidence...00Z Update...
Low to medium confidence on cigs and vsbys.
High confidence on all other elements.
Martin
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 37 55 26 46 / 0 60 40 0
Atlanta 39 55 24 41 / 0 60 30 0
Blairsville 30 47 16 37 / 0 80 40 0
Cartersville 35 49 19 39 / 0 70 30 0
Columbus 40 64 28 50 / 0 50 30 0
Gainesville 37 50 24 43 / 0 60 40 0
Macon 39 64 30 52 / 0 40 30 0
Rome 36 44 21 42 / 0 70 30 0
Peachtree City 37 59 23 44 / 0 50 30 0
Vidalia 41 65 36 53 / 0 20 40 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 7 AM to 7 PM EST Thursday for the
following zones: Catoosa...Dade...Walker...Whitfield.
Winter Weather Advisory from 3 PM to 11 PM EST Thursday for the
following zones: Fannin...Gilmer...Murray...Towns...Union.
&&
$$
SHORT TERM...Martin
LONG TERM....Vaughn
AVIATION...Martin
Area Forecast Discussion
National Weather Service Goodland KS
614 PM MST Wed Jan 5 2022
.UPDATE...
Issued at 535 PM MST Wed Jan 5 2022
Based on radar/observational trends.. the Winter Weather Advisory
was expanded to include Kit Carson county, CO.
&&
.SHORT TERM...(This evening through Friday)
Issued at 148 PM MST Wed Jan 5 2022
At the start of the short term period, current RAP analysis shows
the CWA having a northwesterly flow aloft being in the back part of
the base of an upper air trough with a shortwave trough also seen in
central CO. SPC Mesoanalysis also shows a good amount of 700mb
frontogenesis lining up from the northwestern part of the CWA to
southeastern parts with the higher amounts lining up well with the
current heavy snow band seen from Imperial, NE to just south of
McCook, NE. The current Winter Weather Advisory for the CWA was
pushed up to just after 19Z as snow started to fall in the northern
parts and visibilities started to drop with the snowfall. There is
also a surface low in central CO due to the shortwave trough aloft.
The northwesterly flow aloft looks to continue through the night
though it looks to speed up as a ridge in the west starts to move
eastward. Coverage in the snow showers look to move south over the
rest of the CWA with the snow looking to possibly end in the early
morning hours of Thursday. Forecasted storm snowfall totals at this
time look to range between 2 to 5 inches for the CWA with the
greater amounts seen in the northeastern quadrant. With winds
gusting up to 25 to 30 mph, blowing snow is possible which will
reduce visibilities in areas when snow is falling. At the surface, a
surface trough looks to move over the CWA keeping the surface winds
more northerly. An arctic air mass is also seen at the 850mb level
moving over the CWA during the overnight hours which looks to drop
temperatures across the CWA below zero. Forecasted overnight lows
look to be in the negative single digits while wind chill look to
drop into the low to middle negative 20s. A Wind Chill Advisory
continues for the overnight hours across the CWA, but it looks like
a possible upgrade might be needed for the northern row of counties,
but this will be monitored as there is not the greatest confidence
the WSW criteria will be met though possible in localized areas.
On Thursday, the northwesterly flow looks to continue through the
day as the front part of the western ridge moves over the CWA. With
the arctic airmass that has moved in along with cloud cover seen
particularly in the eastern part of the CWA, daytime high
temperatures look to range from the lower teens in the east to the
lower 20s in the west. Winds look to turn counterclockwise from
northerly to southerly during the day from west to east as a surface
trough looks to move into eastern CO by the evening hours. Overnight
lows look to range between the negative single digits in the east to
the upper positive single digits in the west. Another Wind Chill
Advisory may be needed in the eastern half of the CWA as wind chill
values approach or just meet criteria in this region, but opt to
hold off for now to see how future guidance looks for the Thursday
night into Friday morning hours.
On Friday, forecast models have shown the ridge to have made it over
the Great Plains region by the afternoon hours. With this pattern
aloft, a warmer airmass looks to move in from the southwest at 850mb
which will help warm temperatures across the CWA a bit. Daytime
highs on Friday look to range from the 30s in the east to near 50
degrees in the far west. Surface winds on Friday look to stay
southerly with the surface trough remaining in CO. Precipitation is
not expected throughout Friday though models show a little bit of a
moister air mass moving in over the CWA by the evening hours.
Overnight lows on Friday look to be between the lower teens in the
east to the middle 20s in the portions of the west.
.LONG TERM...(Saturday through Wednesday)
Issued at 210 PM MST Wed Jan 5 2022
The Saturday through Wednesday time period is expected to remain
dry.
Models show a hint of precipitation over the west-central portion
of the forecast area as an upper trough extending south of a low
moving across Canada sweeps East of the Rockies. Highs in the 40s
on Saturday drop to between 10-15 Saturday night with highs
reaching 35-40 on Sunday. The colder air starts to push out of
the area Sunday night and Monday with lows 12-18 Sunday night
warming to 45-50 on Monday.
Warm temperatures will continue on Tuesday and Wednesday with
highs in the 50s and lows mainly in the upper teens to middle 20s
each day. Northwest upper flow transitions from the northwest in
the wake of the upper trough to a more chaotic westerly flow by
the middle of next week as short wave activity moves into the
western U.S. via the southern branch of the upper flow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 532 PM MST Wed Jan 5 2022
Adverse aviation conditions are anticipated through tonight at
both terminals.. mainly via reduced visibilities and low ceilings
associated with snow. While snow will end by sunrise.. MVFR
ceilings may linger through mid-late Thursday morning. NNE winds
at 15-20 knots will gust to 25-30 knots this evening.. backing to
the N and decreasing to 10-15 knots late tonight.. becoming light
and variable by late Thursday morning.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Winter Weather Advisory until 7 AM MST /8 AM CST/ Thursday for
KSZ001>004-013>016-029.
Wind Chill Advisory until 11 AM MST /noon CST/ Thursday for
KSZ001>004-013>016-027>029-041-042.
CO...Winter Weather Advisory until 7 AM MST Thursday for COZ090-091.
Wind Chill Advisory until 11 AM MST Thursday for COZ090>092.
NE...Winter Weather Advisory until 7 AM MST /8 AM CST/ Thursday for
NEZ079>081.
Wind Chill Advisory until 11 AM MST /noon CST/ Thursday for
NEZ079>081.
&&
$$
UPDATE...VINCENT
SHORT TERM...076
LONG TERM...LOCKHART
AVIATION...VINCENT
Area Forecast Discussion
National Weather Service Green Bay WI
838 PM CST Wed Jan 5 2022
New Information added to update section
.UPDATE...
Issued at 835 PM CST Wed Jan 5 2022
Mesoscale models show persistent bands of lake-enhanced snow
showers moving through Door County overnight into Thursday, with
potential for an additional 3 to 5 inches of accumulation.
Favorable conditions will continue through early to mid afternoon
Thursday. A Winter Weather Advisory has been posted for Door
County through 3 pm Thursday.
&&
.SHORT TERM...Tonight and Thursday
Issued at 243 PM CST Wed Jan 5 2022
The latest RAP analysis and satellite/radar imagery show low
pressure moving over Lake Huron with a sharp surface trough
extending west across northern WI early this afternoon. Beneath
broad upper level trough, more intense snowfall is occurring along
and ahead of this surface trough as it slides south over northeast
WI. Visibilities have been dropping to about 1/2 mile in this snow
band, that could lead to a quick 1/2" to 1" of snow as it passes.
This band of snow will likely impact the afternoon commute over
the Fox Valley and Lakeshore areas and make for difficult driving
conditions. Will continue to draw attention to the impacts in the
SPS and social media. Behind the snow, snowfall rates diminish
relatively rapidly, so don`t think an upgrade or extension to
current winter headlines is warranted. Focus continues to revolve
around snow and wind trends in the short term.
Tonight...Low pressure will quickly exit the northern Great Lakes
in the evening, leaving behind broad cyclonic flow. Forecast
soundings show deep saturation continuing through the night though
lift will remain weak for the most part. Increased ascent will
likely return late in the night ahead of an amplifying trough over
the northern Mississippi Valley. But with colder air advecting
into the region, the ascent will likely take place above the
dendritic growth zone, and flake size should be relatively fine.
Therefore expect light snow and flurries to continue for much of
the night with only minor accumulations less than an inch at most
locations. Concern is higher for accumulations over Door and Vilas
counties where snow bands off Lake Superior may lead to more
intense accumulations. Confidence is relatively low in regards to
the location/persistence of these bands, so do not foresee an
extension of the winter hazard headlines. Temps to fall into the
mid single digits to mid teens across the region. Winds will
diminish as well, which will reduce impacts from blowing and
drifting after midnight.
Thursday...The amplifying upper trough will pass across the region
on Thursday. With flow off Lake Superior and deep saturation
continuing through the day. Periods of light snow and flurries
will likely continue, though weak ascent should mean minor
accumulations. Most locations should see up to 1" of additional
accumulations. Locally higher amounts are possible over Door and
Vilas county should any lake effect snow bands develop. Colder
highs mainly in the teens.
.LONG TERM...Thursday Night Through Wednesday
Issued at 243 PM CST Wed Jan 5 2022
Main systems/features to focus on during the long term include a
clipper system grazing the area Friday night and again early/mid
next week, strong WAA and possible light precip on Saturday and
a strong cold front Saturday night. Lake effect snow is expected
Thursday night into early Friday and again Saturday night into
Monday. Temps will be a quite the roller coaster ride with temps
starting below normal on Friday, then near normal on Saturday,
then falling well below normal for Sunday into Monday.
Thursday night into Friday...lake effect snow showers will be
ongoing across north central WI and look to continue for much/all
of the night as N/NW winds continue to flow over Lake Superior
with delta Ts in the lower 20s and favorable inversion heights.
Another band of lake effect snow could impact parts of Door County
in the evening hours as well. All of the lake effect snow
activity will wane through the night and into early Friday morning
as trajectories become less favorable. Additional accumulations
will be minor, mainly confined to Vilas County and possibly
northern Door County. Elsewhere, some flurries will be possible
with the lingering deep layer moisture and very weak lift. Very
cold air will be invading the area through the night, with some
spots in the teens below zero (where skies clear out). Could flirt
with wind chill criteria in the colder spots, mainly across
central WI. Dry and cold conditions are expected on Friday as high
pressure briefly drifts across the area. Highs look to be in the
upper single digits in the cold spots of central and northern WI
to the teens over eastern WI.
Friday night into Saturday...northern WI may be grazed by a
clipper system crossing across Canada, but think any precip will
be on the light side. WAA will really ramp up as south winds
increase up to 25-30 on Saturday with 850mb temps climbing into
the single digits below zero. The WAA could lead to some light
precip as well (likely in the form of drizzle as moisture in the
mid levels will be lacking). Lows look to be warmer than Thursday
night, mainly in the -5 to 10 degree range. Highs on Saturday will
be near normal, with most spots in the middle 20s to around 30.
Rest of the long term...any light precip or drizzle will end
Saturday night as a strong cold front sweeps across the area. Then
another bout of lake effect snow is expected, mainly over far
north central WI. Monday looks like the best trajectories for the
snow belts of north central WI, where some accumulation will be
possible. Arctic air will push across the area Sunday into Monday
(850mb temps as cold as -25C), with Monday being the coldest day
(likely of the entire winter) with highs struggling to reach zero
degrees across parts of central and north central WI, with single
digits above zero farther east. Temps will moderate toward mid-
week with another possible clipper system bringing precip to the
area.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 545 PM CST Wed Jan 5 2022
A slow moving upper trough will be moving across the region over
the next 24 hours, leading to poor flying conditions for most of
the duration. Expect light snow and associated MVFR conditions to
prevail through most of the period. Several models suggest a
slight increase in snow coverage/intensity late tonight into
Thursday morning, so will add TEMPO groups for IFR conditions
during that time period. There may also be some lake enhancement
at times in Vilas and Door counties, which could lead to periods
of moderate snowfall. Gusty northwest winds will diminish a bit
overnight, so blowing/drifting snow will become less of a concern
at the airports.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 3 PM CST Thursday for WIZ022.
&&
$$
UPDATE.........Kieckbusch
SHORT TERM.....MPC
LONG TERM......Bersch
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Grand Rapids MI
1045 PM EST Wed Jan 5 2022
LATEST UPDATE...
Update
.UPDATE...
Issued at 1044 PM EST Wed Jan 5 2022
Have decided to not make changes to the going headlines. The
Winter Storm Warning and Winter Weather Advisory were extended on
the day shift and have opted to let them continue as is at this
point.
Regional radar imagery at present is not impressive and
visibility here at Grand Rapids where some of the highest
reflectivity is...is only at 3 miles. The visibility at Muskegon
is at a half mile, which is currently the worst in the forecast
area. There is a chance that the lake effect snow increases once
again tonight as we are currently in a period where there is shear
in the profile due to a boundary sagging south through the
forecast area. Southwest flow is in place across much of our area
with winds shifting to the northwest over Wisconsin. The cold
front extends from near Houghton Lake to near Muskegon. The front
may act to reintensify the lake effect overnight, but at this
point it does not look imminent. NAMnest BUFKIT overviews show
solid lift showing up once again overnight at Grand Rapids. With
winds of 30-40 knots remaining in the cloud layer tonight which
would transport bands inland do not feel comfortable yet dropping
headlines. Considered taking the eastern row out of the advisory,
but in the end decided to stay the course and see how things play
out into the overnight.
&&
.DISCUSSION...(This evening through next Wednesday)
Issued at 323 PM EST Wed Jan 5 2022
- Extended Headlines into Friday
We have extended our Winter Storm Warning headlines until 10 am on
Friday and the Winter Weather Advisory headlines until 1 pm
Thursday.
The cold air is now rushing in behind the departing surface low,
which is currently over northern Lake Huron. The core of
strongest winds is moving out of the area, even so winds will
continue to gust in the 25 to 35 mph range well into the evening
across the area. As for the snow, we continue to see heavy snow in
the Grand Rapids to Holland area since we have that favored WSW
wind direction continuing. This area of snow will diminish some
into this evening.
However there will be a second period of heavy snow that will move
south from the Ludington area early this evening associated with
the back edge of a layer of warmer air between 4000 ft to 10000
ft. This will act like a cold front an enhance the snow as it
moves south. That area of snow should reach the I-96 area by
midnight. As this band moves south, during the hour or so it takes
to come through the HRRR is showing 1 to 2 inch per hour snowfall
rates.
Once this moves through we are in more typical lake effect set up
but with inversion heights over 10000 ft at times into Friday the
periods of heavy snow will continue. This will mean snowfall rates
of 1 to 2 inches and hour at times into early Friday morning west
of US-131. Which is why we continues the Winter Storm Warning into
Friday for the western zones.
Inland of the lake shore zones the snow showers will be less
active once the wind is more from the northwest so we ended the
Winter Weather Advisory inland around midday on Thursday.
Friday should see us back on the anticyclonic side of the polar
jet so that will take lake effect snow out of play for this area
by midday. It will remain very cold through Friday.
- Warmer Saturday only to get even colder by Monday
The next system tracking east from the Pacific wave train brings
warming ahead of it for our area on Saturday. The storm system
associate with that next jet streak will track well north of
here, toward James Bay. The entrance region to that jet will help
develop and area of precipitation over us Sunday. This may be a
mix of rain and snow depending on just how much warm air gets up
there.
No matter what happens with that the coldest air of the season
follows this for Monday and Tuesday. This will bring more lake
effect snow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 729 PM EST Wed Jan 5 2022
MVFR conditions will be prevalent at all TAF sites over the course
of the next 24 hours or through 00Z Thursday evening.
Stratocumulus clouds with bases ranging between 1,000ft and
2,500ft will continue to pour off Lake Michigan and spread inland.
There may be some intermittent times at JXN and LAN where they
lift to VFR, but that should not be long lived.
As for the lake effect snow showers, the flow or wind driving the
bands of snow showers is in the process of veering from
west-southwest, where it was all day today, to west-northwest.
KMKG, KGRR and KAZO will continue to be the most affected TAF
sites when it comes to MVFR and IFR visibilities. Conditions will
be improving, visibility wise, at JXN and LAN.
Winds will be coming down through the course of the night at the
gusts should settle out of the obs between 100am and 400am.
&&
.MARINE...
Issued at 323 PM EST Wed Jan 5 2022
We will continue the gale warning as is into this evening. Then
expect a Small Craft Advisory into Friday morning since the storm
does not totally move out of this area until Friday during the
day.
Once this storm is out of the area the next system comes in and we
may need gales for Saturday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Storm Warning until 10 AM EST Friday for MIZ037-038-043-
044-050-056-057-064-071-072.
Winter Weather Advisory until 1 PM EST Thursday for MIZ039-040-
045-046-051-052-058-059-065>067-073-074.
LM...Small Craft Advisory until 1 PM EST Friday for LMZ844>849.
&&
$$
UPDATE...Duke
DISCUSSION...WDM
AVIATION...Duke
MARINE...WDM
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
856 PM EST Wed Jan 5 2022
.SYNOPSIS...
A weak front will drift in from the northwest tonight and stall
while extending from Georgia across the Carolinas through late
Thursday. Low pressure developing along the front is expected to
move across the Carolinas on Thursday and Thursday night, bringing
precipitation that could be wintry across the mountains and
foothills. Cold high pressure will build back in from the west and
north Friday and Saturday. Another cold front and low pressure
approaches on Sunday reaching the Carolina coast early Monday.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
Evening Update...Blended in some warmer guidance for low temps based
on current ob trends and upward tick seen in most near term models.
Still expect lows a couple degrees abv normal. Patchy fog is
possible across the Piedmont and srn NC mtn valleys arnd daybreak,
yet likely not dense or widespread enuf for a DFA.
As of 245 PM EST Wednesday: Sfc high pressure will continue to
weaken across the area through the afternoon hours. A moisture
starved cold front will track across northeast Georgia and the
western Carolinas late this afternoon into the early evening hours.
Winds will remain SW`ly ahead of the FROPA turning NW`ly behind the
FROPA. Dry conditions can be expected the rest of today into
tonight. High temps this afternoon will be 5 to 8 degrees above
normal thanks to great insolation and SW`ly flow. Low temps tonight
will also be 5 to 8 degrees above normal due to increasing high
clouds. Model guidance has been hinting at patchy fog developing
around far SE CWA tonight, mainly for areas near the CLT metro.
However, confidence on this occurring is low.
The aforementioned frontal boundary will stall across the
central Carolinas through Thursday evening. An area of low pressure
will ride up along this stalled frontal boundary tracking into
northeast Georgia and the Carolinas Thursday afternoon into Thursday
night. So, we will start out dry during the first part of the
morning Thursday. This area of low pressure will bring mainly rain
chances east of the mountains with snow chances most likely across
the mountains. Latest model trends show the system speeding up a
bit, allowing for a quick transition from rain to snow across the
mountains. However, periods of wintry mix, mainly in the form of
sleet, will likely mix in with the rain/snow across the mountains
Thursday afternoon into early Thursday evening before temps drop
below freezing. Around or just after 00z, precip should switch to
all snow across the mountains with rain continuing the east of the
mountains. Temps across the NC Foothills and Piedmont, and the far
northeastern SC Upstate could drop near or below freezing late
Thursday evening allowing a quick shot of snow to develop right
behind the departing area of low pressure. No accumulations are
expected at this time for these particular areas. The entire system
should track away from the area around 0300z. However, NW flow is
expected continue across the NC/TN border. The highest snowfall
amounts look to fall along the NC/TN border and across the higher
elevations (above 3500 feet). A Winter Storm Warning was issued for
the higher elevations, (above 3500 feet), for counties along the
NC/TN border. Snowfall amounts for the high elevation warning areas
could see up to 6 inches. A Winter Weather Advisory was also issued
counties along the NC/TN border for the lower elevations, (below
3500 feet). Snowfall amounts for the low elevation advisory areas
could see up to 4 inches. A Winter Weather Advisory was also issued
for the higher elevations of Buncombe, Macon, and Jackson counties.
These locations could see up to 3 inches of snow. Breezy NW winds
will be in place behind the departing system Thursday night into
early Friday morning leading to near advisory wind chills in the
higher elevations (-5 to -10 degrees). High temps on Thursday will
remain 3 to 6 degrees above normal outside the mountains and near to
just below normal across the mountains. Thursday night lows will
drop below normal, ranging from the teens in the mountains to the
mid to upper 20s outside the mountains.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
As of 1230 PM Wed: Northwest flow will be underway across the
southern Appalachians at the start of the period Friday morning. Prog
soundings from the 12km and 3km NAM both indicate shallow saturation
in the upslope layer; sufficient CAA will have occurred by that time
that this moisture will be at temperatures supportive of ice
nucleation. No CAPE is noted beneath the inversion and we won`t have
good Great Lakes moisture fetch. A mentionable PoP will be warranted
well into the day Friday but most likely without any additional
accumulation. Winds will diminish thru the day as high pressure
shifts in from the lower OH Valley. It will be cold. Max temps will
struggle to get out of the teens in the high elevations along the TN
border, especially with the expectation of lingering cloud cover.
Most of the Piedmont will remain in the lower to mid 40s even under
plentiful sunshine. The sfc high will remain transient under a flat
upper ridge, centering north of the region Friday night. Slight CAA
will continue for a portion the night, which will somewhat offset
otherwise good radiational cooling. Min temps mostly bottom out
around 5 degrees below normal.
The high will push off the East Coast Saturday and return flow will
begin atop it, ahead of the next trough and front, but any PoP and
even most of the cloud cover should not return until after 00z Sun.
Max temps will moderate somewhat Saturday (especially in the higher
mtn elevations) but remain a few degrees below normal.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 100 PM Wed: Seasonably strong high pressure will move further
into the Atlantic Saturday night and Sunday. Upper pattern will
amplify, with ridge strengthening over the high but also with broad
trough pushing from the Plains to the upper Mississippi Valley
over the same timeframe. A cold front will push east, extending
from sfc low near James Bay. Models have trended slightly later in
bringing precip to our doorstep with the front, giving the high
more time to move offshore. The upper pattern also appears less
conducive to CAD than it had on runs from a day ago. The latest
progs still depict nondiurnal temp trends Saturday night; question
remains how much radiational cooling will be able to occur before
overtaken by clouds and WAA.
The potential for wintry precip on the warm side of this system
does appear lesser than what we had previously advertised, but
blended guidance still depicts temps cold enough at the onset
of PoPs to warrant a fleeting mention for some of the colder mtn
valleys and northern foothills. Profiles at onset would point to
a freezing rain and sleet threat if anything. Precip will continue
thru Sunday, potentially transitioning to snow across a portion of
the mountains Sunday night. Locally heavy rain could develop Sunday
as a small amount of MUCAPE develops above WAA-induced inversion,
and with upper divergence shifting over the area in conjunction
with RR quad of 250mb jet. Cold and dry high pressure will return
once again following departure of front Monday, persisting thru
the end of the forecast period.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: VFR conds and light winds overnight across
all TAF sites as a broad sfc trof crosses the area. Things will
change during the afternoon period as a moist storm system advances
on the area from the southwest. Expect CIGS to drop into the
MVFR/IFR range across the mtn valleys as light rain and perhaps a
little snow/sleet mix at KAVL begins arnd 21z. Low CIGS and precip
spread east quickly thru the afternoon and all non/mtn sites shud
see restrictions in the MVFR/IFR mid afternoon thru the remainder of
the period. It will take a while for lower flight conds to reach
KCLT, but expect at least MVFR CIGs in -RA by 00z. Winds will begin
the period light and generally from SW to NW before becoming defined
sw/ly during the daytime with low-end gusts probable at KAVL and the
Upstate terminals.
Outlook: High pressure and VFR conds return Friday into the weekend.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Winter Weather Advisory below 3500 feet from noon Thursday to
7 AM EST Friday for NCZ033-048>052-058.
Winter Storm Warning above 3500 feet from noon Thursday to 7
AM EST Friday for NCZ033-048>052-058.
Winter Weather Advisory above 3500 feet from noon Thursday to
7 AM EST Friday for NCZ053-059-062-063.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...AP/SBK
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...SBK
Area Forecast Discussion
National Weather Service Indianapolis IN
934 PM EST Wed Jan 5 2022
.Forecast Update...
Issued at 934 PM EST Wed Jan 5 2022
Most of the forecast is in good shape this evening. As of 9 PM EST,
temps were already down as low as 11-12 degrees in the northwest.
Latest hourly numerical guidance suggests forecast lows are a too
warm by 2-3 degrees and have made this adjustment pretty much across
the board, as even with increasing mid and high cloud, winds
beginning to relax and the continuing cold advection overnight
should allow temps to continue to drop slowly but steadily. single
digits should be achievable across the northwestern third or so of
the area.
&&
.Short Term...(This Evening through Thursday Night)
Issued at 248 PM EST Wed Jan 5 2022
Quick Summary:
- Windy conditions will continue through early evening with peak
gusts at 40-45mph.
- Below zero wind chills tonight and Thursday night.
- Trends remain largely south of central Indiana with the impactful
snowfall for Thursday.
Meteorological Analysis:
A chilly...windy afternoon continues for the region as central
Indiana resides within the backwash of the low pressure system and
associated cold front that has moved off to the east. Still a tight
surface pressure gradient in place which has enabled gusts to
routinely peak at 40-45mph across the northern half of the forecast
area so far today. Stratus remained over the northwest half of
central Indiana with partly cloudy to mostly sunny skies further
south and east. A large temperature gradient remained from northwest
to southeast as of 18Z...ranging from the lower 20s to upper 30s.
Three primary issues are in play for the next 36 hours and we will
discuss in order:
1) Strong winds/Wind Advisory through early this evening
2) Snow chances with the upper wave passing by to the south on
Thursday
3) Coldest air of the season making a brief but notable appearance
across central Indiana
A quasi-zonal flow aloft will transition to a broad trough over much
of the eastern US through Thursday night as another upper level wave
tracks through the region on Thursday. The upper wave will bring an
axis of snow across the lower Ohio and Tennessee Valleys on Thursday
with progressively colder air advecting in from the north courtesy
of a 1045mb+ high pressure sidling down the lee side of the Canadian
Rockies and set to expand across the region by Thursday night and
into Friday.
Initially for the next few hours...gusty winds will persist as
central Indiana remains within a tighter pressure gradient between
the departing surface low and trailing surface trough across the
Great Lakes and the strong high out to the northwest. The gradient
will relax tonight as the low lifts into Quebec with wind gusts
gradually dropping through the evening and diminishing entirely
overnight. While just the far northern portions of the forecast area
have been straddling wind advisory criteria over the last couple
hours...plan to leave the headlines up as is through 23Z. The axis
of lower clouds lingering over the northern Wabash Valley should
largely mix out into the evening hours but be quickly replaced by
expanding mid and high level cloud cover in advance of the upper
wave approaching from the west.
Trends continue to focus on a suppressed track to the upper wave and
expected swath of snowfall that will set up largely south of the
Ohio River on Thursday. The strength of the expanding high pressure
east of the Canadian Rockies is likely keeping the upper wave from
taking on a more amplified and phased look until the system has
largely passed by late Thursday. High confidence now exists in the
best diffluence aloft aligning across western and central Kentucky
Thursday with deeper low level forcing further south into the
Tennessee Valley. With an axis of frontogenetical forcing setting up
over these features...anticipate the heaviest snow with this upper
wave to align across northern Tennessee and the southeast half of
Kentucky with progressively lighter amounts of snow further north
and west.
At this point...the only mystery still in play is exactly where the
sharp northern edge to the snow will line up...either sneaking up
briefly into the far southern portion of the forecast area or just
south across far southern Indiana. To allow for any last minute
wobbling to the upper wave track...have nudged up snowfall potential
slightly across the far southern row of counties with up to a half
inch or so from Vincennes to Seymour...dropping off rapidly to a
tenth or so as far north as Bloomington and Greensburg. Despite
model soundings showing notably drier mid level air further north
across central Indiana on Thursday...the presence of weak forcing
aloft should be enough to generate flurries up to a Terre Haute-Indy
Metro-Muncie line for a few hours sandwiched around midday Thursday
before the upper wave quickly pivots off to the east and all snow
wraps prior to sunset Thursday. Any impacts from snow locally will
be minimal at best across south central Indiana and nonexistent
further north. Clouds will diminish Thursday night as the large
Canadian high pressure builds in.
Temps...a bitterly cold airmass will advect into the region through
the period bringing the coldest air of the season to this point.
Thick cloud cover Thursday will limit temp rises and low level
thermals overall support a mighty struggle for many locations to
make it to 20 degrees. Winds will be lighter on Thursday...but still
up enough to keep wind chill values in the single digits and teens.
Lows tonight will be in the teens but the core of the coldest air
will arrive Thursday night as lows are expected to bottom out in the
single digits. Wind gusts to near 20mph Thursday night may bring
subzero wind chills at times.
&&
.Long Term...(Friday through Wednesday)
Issued at 248 PM EST Wed Jan 5 2022
Friday and Friday night
Cold high pressure at the surface and brief ridging aloft will keep
the weather dry and cold across central Indiana on Friday into
Friday night. Friday morning wind chills could be around -10 in the
northwestern forecast area.
Saturday into Sunday
A large upper trough will approach the area Saturday and move in on
Sunday. Accompanying the upper trough will be a cold front with
another good shot of cold air behind it.
A strong low level jet (over 50kt at 850mb) will be a feature of the
system, and this will tap into some Gulf moisture. Precipitable
water values will be around 1 inch, especially south. Thus, plenty
of moisture is available with the system. The strong front, low
level jet, and an upper jet will bring good forcing with it too.
Thus, precipitation looks to be a good bet.
The antecedent airmass will be dry, so it will take a while for the
atmosphere to moisten up, so precipitation wouldn`t likely reach the
ground until late in the day Saturday or early Saturday evening. By
the time this occurs, the low level jet will have brought in warm
air aloft, more than enough to melt any frozen material falling
through the column.
Thus, expect rain to reach the ground. There is some concern that
the ground may still be cold enough (given the period of cold
temperatures in the days before) for some of the rain to freeze on
contact. However, for the moment, believe the strong warm advection
with the system will allow for the ground to recover enough by when
the rain hits the ground. Will keep rain as the precip type, but
will also keep an eye on it.
The cold front will move through on Sunday, ending the
precipitation. Colder air moving back in may allow for a brief mix
or changeover to snow before ending.
Will go low PoPs on Saturday afternoon, then high PoPs Saturday
night. On Sunday, will have low PoPs as the system exits.
Monday through Wednesday
Surface high pressure will dominate through much of this period,
although a frontal system could try and move in on Wednesday.
However, any moisture for this system will be kept south of the
area. Will go dry through the period.
Cold air will persist into Tuesday, then some moderation in
temperatures will likely occur by Wednesday as the surface high
moves off to the east.
&&
.Aviation...(00Z TAF Issuance)
Issued at 610 PM EST Wed Jan 5 2022
IMPACTS:
* Wind gusts continuing into the early overnight as high as 21-26KT
at times.
* Return of MVFR ceilings late tonight into Thursday.
* Occasional flurries or light snow showers at BMG and perhaps
IND/HUF.
DISCUSSION:
Wind gusts continue in the wake of a cold front that moved through
the area this morning. Although gusts will continue to weaken, some
gustiness should continue into the late evening or early overnight
at times per HRRR soundings. Winds throughout the period will
generally be from 280-300 degrees.
A broad upper level wave moving through the region will promote the
return of some high end MVFR ceilings late tonight into Thursday, as
well as potential for some occasional flurries or light snow showers
at the southern 3 sites. Impact is likely to be little to none with
these, with the more significant snow expected to be south of the
sites.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Update...Nield
Short Term...Ryan
Long Term...50
Aviation...Nield
Area Forecast Discussion
National Weather Service New Orleans LA
728 PM CST Wed Jan 5 2022
...EVENING UPDATE...
Performed a gridded update to reflect obs/short-range guidance
tonight through Thursday. No major adjustments needed tonight,
only looked closer at the potential for patchy fog through
daybreak Thursday. Guidance is in pretty good agreement
highlighting the eastern half of the CWA, primarily along/east of
I-55 to the MS coast. This makes sense as guidance hints at subtle
SFC to 925mb moisture advection steadily increasing over coastal
areas, as the surface high to our east breaks down and deeper S to
SSW Gulf fetch/flow takes over. Cloud coverage will remain partly
to mostly cloudy at times with this moist layer up to the base of
a subsidence inversion around 800mb. Cloud ceilings will continue
to lower through the morning hours especially where the better
surge of low-level moisture resides across coastal areas. Went
ahead and highlighted patchy fog for the aforementioned locations
through daybreak, but am not anticipating widespread dense fog
concerns.
Meanwhile, a cold front is barreling down from the northwest
Thursday morning thanks to a re-enforcing push of CAA dives south
over the central US helping to accelerate the front our way. Still
looking like we will see weak cyclogenesis along the front over
the Arklatex region tonight, tracking northeast over central MS/AL
early Thursday which will only aid in increasing CAA spreading
south. Did get cute with temperatures as HRRR trends are in pretty
good agreement in regards to timing, allowing for a large portion
(eastern 2/3rds) of the CWA to warm up enough mid/late morning
and afternoon before the front swings through. Riding the
deterministic NBM for BTR to MCB on east which gets these areas
into the upper 60`s to lower 70`s, but went slightly warmer for
the southshore which may get closer to the mid 70`s before the
front passes. With the weak surface low to our north pushing well
away from the area, surface winds continue to transition more from
the SSW to eventual SW, reducing directional shear. Only main
forcing will come from the front itself as it races east, but with
some surface heating, a thin corridor of MLCAPE ~250-750J/kg
could develop out ahead. Can`t rule out a rumble of thunder for
near-shore or marine areas within deeper instability, and for
coastal MS where longer diurnal destabilization will build
throughout the day owing to a few cells or line segments
developing along the front. But overall very dry air aloft will
put a lid on vertical growth of updrafts revealing a very low
severe weather risk.
Winds will sharply transition and pick up after the front passes,
and will confidently keep the 90th percentile of NBM guidance in
place through the evening and parts of the overnight hours as
temperatures plummet Thursday night/Friday morning thereafter.
KLG
&&
PREV DISCUSSION... /issued 338 PM CST Wed Jan 5 2022/
SHORT TERM (Tonight through Saturday)...
We saw warmer temperatures today across most areas compared to
yesterday and Monday, with most of SE LA sitting in the mid 60s to
low 70s. Likely staying dry for the rest of this afternoon and
evening as overnight lows drop into the low to mid 50s for most
of the CWA. Thursday high pressure is pushed eastward as a cold
front approaches the area in the morning. As this front pushes
through mid morning into the early afternoon we may see some
showers form, mainly for northern and eastern areas, but moisture
is fairly limited with this front. Not expecting much in terms of
thunder given the very limited convection, but we won`t completely
rule it out.
Behind the front cooler air moves in once again, with most areas
north of Lake Pontchartrain approaching freezing temperatures
Friday morning. While drier air moves in behind the front, it
doesn`t look to last long as a disturbance out in the Gulf waters
looks to move north into our area on Saturday bringing some
moisture back in. PoPs generally start out in the 20-30% range
early Saturday, but quickly rise as the disturbance moves onshore
and our next cold front approaches the area on Sunday. This brings
chances of showers back into the forecast on Saturday.
-HL
LONG TERM (Sunday and Beyond)...
The beginning of the long term period will be active as an upper
level trough moves across the Northern Plains and Upper Midwest on
Sunday. A cold front at the surface is expected to slide down into
the region through Sunday. The disturbance that moves north from
the Gulf on saturday also gets pulled into the main energy
associated with the trough and surface front on Sunday. This
brings a big increase in PoPs with the amount of moisture
available, generally 40-60%b out ahead of the front and then
increasing up to 70-80% as the front arrives. This brings a good
chance of showers on Sunday, with a possibility of some
thunderstorms as well. Taking a look at sounding analysis,
instability and convection seem to be trending upward compared to
previous model runs. CAPE values up to 1700J/Kg and SRH values
support the chance of thunderstorms, but the lower SHEAR and lack
of low-level winds don`t support much in terms of a severe risk.
This is something to continue to monitor as this event gets closer
as a change in timing of the front could change things slightly.
Behind the front high pressure is expected to build back in,
keeping PoPs low for most areas through mid-week. We also see some
cooler air move in behind the front, with a return to the low to
mid 30s for most northern areas. MaxT`s on Monday and Tuesday only
looking to reach the low to upper 50s, but a return to the 60s
looks reasonable by Wednesday.
AVIATION (00Z TAF DISCUSSION)...
Low to mid-level clouds continue across a large majority of all
terminals this evening, with CIGs ranging 6.5 to 8.0kft AGL.
Expect CIGs to steadily lower tonight bringing periods of MVFR
categories into daybreak. Additionally, guidance is in better
agreement for the potential of some patchy surface fog, primarily
for terminals along and east of I-55 to parts of the Mississippi
coast. Here, periodic lower flight categories will be possible
before, during and shortly after daybreak, but will improve
steadily thereafter with intermittent low CIGs persisting.
A cold front is expected to swing through from west to east
beginning in western areas mid/late morning Thursday, pushing to
the east Thursday afternoon. Expect quick surface wind transition
and increase from the W to eventual NW as the front passes. Included
VCSH primarily for central and northern terminals for the
potential of a passing light shower ahead of the front, but
the chance for widespread heavy rain or severe weather is looking
very low. Strong northwesterly surface to low-level winds will
persist through the evening and overnight hours on Thursday. KLG
-HL
MARINE...
Onshore flow continues through the rest of today, gradually increasing
through the rest of the afternoon and this evening. A cold front
will be approaching the area tomorrow and will move down through
the coastal waters later into the evening. Behind the front winds
shift to offshore and strengthen to the 15 to 20 knot range. While
the direction may vary, winds decrease briefly before they become
elevated once again heading into the late weekend with yet
another cold front arriving through Sunday. HL
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 52 64 28 52 / 10 30 0 0
BTR 55 68 33 54 / 10 20 0 0
ASD 54 73 33 55 / 10 20 0 0
MSY 57 74 40 55 / 10 10 0 0
GPT 54 73 36 56 / 10 20 0 0
PQL 51 74 33 55 / 10 30 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Louisville KY
1034 PM EST Wed Jan 5 2022
.Forecast Update...
Issued at 1033 PM EST Wed Jan 5 2022
...Winter Storm Warning Expanding, and Upping Snow Totals Across the
Winter Storm Warning...
After getting a good look at the 00z data, a NW expansion of the
Winter Storm Warning seems prudent. There has been a steady upward
trend in expected snowfall totals in a lot of the hi-res output over
the past 24 hours. In addition, the 00z HREF came in with a pretty
good jump as discussed below. This data trend, combined with the
setup and potential for a persisting frontogenetical band is enough
to really buy into the higher totals. In addition to the NW
expansion, will be likely upping totals into the 6 to 8" range for
some across the Warning area overnight.
Previous Update...
Issued at 919 PM EST Wed Jan 5 2022
Overall, no changes to the going forecast, but there are some trends
in the latest models, and a few observations from the overall setup
discussed below. Otherwise, the previous forecast looks pretty good
for now.
Things are quiet across the CWA at this hour with some upper clouds
streaming overhead, and post frontal gusts beginning to subside.
Temperatures are currently running in the upper 30s to around 40
over much of Kentucky, but we have already dropped to the low 30s
across our northern tier of IN counties. Temps are expected to
quickly fall from here, as we will likely be in the 20s over most of
our area by around Midnight or just after. From there, we dip into
the upper teens (north) to upper 20s (southeast) by sunrise. Bottom
line, cold air will be in place for the onset of snow by mid morning
across our area, and the overall thermal profile will remain
conducive for all snow throughout.
Taking a look at the afternoon/evening data, we are still seeing a
trend toward more aggressive amounts across our current Winter Storm
Warning area. In fact, if trends hold into the 00z data we may need
to expand our Warning another tier or two of counties to the NW. The
18z NAM, 3km NAM, and HRRR are all trending higher and a bit farther
NW. Our current forecast matches the HREF data quite well, but
expect that the 00z HREF could trend upward given more hi-res
support for higher totals with the latest runs. Something to watch
for overnight.
Taking a look at the overall setup, the higher totals are not
unreasonable given that the timing of the phase between the northern
clipper and the southern stream system looks to be pretty good. This
give us the "hybrid" type of clipper setup referred to in the
previous discussion, where some Gulf moisture will certainly be
tapped into across our southern and eastern CWA. Cutting a cross
section through the upper jet structure does reveal a sloped frontal
zone that would allow for good lift up through the DGZ, and beyond.
One thing that is popping out in the cross sections, however, is
that there looks to be a sharp cutoff in the deepest moisture the
farther north you go. You still get saturation into the DGZ, but
really on the bottom half or so. This explains the sharp gradient in
increasing forecast snow amounts once you get farther south and east
of the of the Ohio River. This is also where the more intense
frontogenetical band will set up.
Given the potential for frontogenetical banding evidenced in the
cross-sections and some negative EPV potential, it does seem
reasonable that the main deformation band across our Warning area
will be capable of at least 1" per hour, if not close to 2" per hour
rates at times. If this feature is able to set up for a few hours
over one region then some of the higher amounts offered by the hi-
res models will be plausible. Some residence time is expected (3 to
4 hours) given the orientation compared to overall motion, but this
won`t quite be like a pivoting deformation band where residence
times are maximized. So, kinda like where we have our totals for now.
Given all of this, currently the swath of 4 to 6" seems pretty
reasonable across our Warning area, and the only questions that
remain are: 1. Will the Warning need to come a bit farther NW, and
2.) will there be some higher amounts possibly over 6"?. Right now,
the best potential for that still seems to be east of I-75, but
something to keep a close eye on.
&&
.Short Term...(This evening through Thursday)
Issued at 255 PM EST Wed Jan 5 2022
...Impactful Snow Expected Thursday...
Latest guidance with the Thursday system is trending faster and
juicier, so timing has been adjusted earlier and snow amounts
generally adjusted upward. Winter Storm Warning has been posted for
much of south central Kentucky and into the southern Bluegrass
region, with a Winter Weather Advisory elsewhere.
A "hybrid" Clipper system is taking shape with a progressive
shortwave trof that will dig deep enough into the Plains and
Mississippi Valley to tap a modest moisture feed from the Gulf. This
phasing will allow precip to break out more quickly across the Ohio
Valley, so QPF has been increased quite a bit for the 12-18Z time
frame (probably more like 15-18Z). Expect the first flakes of snow
to fly by mid-morning. The intensity picks up around midday or
shortly after in a deep and saturated DGZ, with the peak time for
snowfall roughly from 17-23Z, give or take an hour or two across the
CWA. Normally it`s difficult to accumulate snow around here during
daylight hours, but air temps in the mid 20s all day, and decent
rates will support a sticking, impactful snow. Upper trof axis
pushes through around sunset, so expect precip to cut off quickly
from west to east. However, with snow ongoing during part or all of
the evening commute, travel impacts are expected even where the
amounts are lower.
The QPF is increased sufficiently from previous runs to give us
pause, but we still have at least moderate confidence in this
forecast which is just a little more conservative than the latest
WPC numbers. This will give us a decent swath of 4-5 inch snowfall
amounts from roughly Bowling Green to Richmond and southward to the
Tennessee line. Will message 3-5" with locally higher totals
possible in the warning area. Confidence is higher in the advisory
area, with totals from around 1 inch in southern Indiana, to 2-4
around Lexington and Frankfort.
Once the snow tapers off Thursday evening, decent cold advection and
favorable radiational cooling will easily drop temps into the single
digits by daybreak Friday over the better snow pack.
.Long Term...(Thursday night through Wednesday)
Issued at 325 PM EST Wed Jan 5 2022
...Very Cold Friday, Significant Rain Possible This Weekend...
IMPACTS:
- Very cold Friday morning (single digits - subzero winds chills)
- Quick warm-up with rain falling on snowpack second half of the
weekend
CONFIDENCE:
- High confidence in very cold temperatures Friday morning
- Medium-high confidence in rain this weekend
DISCUSSION:
Friday...
Bitter cold temperatures associated with a strong Canadian
sfc high will drop in across the Ohio Valley on Friday. This will be
the coldest air we`ve seen this winter as morning lows will bottom
out mostly in the single digits. Factoring in a NW wind between 5-10
mph, wind chill values will drop below zero. Even with some
sunshine, highs only reach the mid 20s during the afternoon.
The Weekend...
High pressure moves eastward Friday night and off the
Delmarva Coast by Saturday evening. While not as bitterly cold as
Friday morning, lows Saturday will be in the low/mid teens but
rebound into the mid/upper 40s by the afternoon thanks to a strong
southerly flow. Saturday night into Sunday, Gulf moisture will be
on the increase thanks to our steady southerly flow. This will
increase moisture over the region and bring rain Saturday night into
Sunday ahead of an approaching cold front. Given the temperature
profiles, expecting all rain across our area as temperatures stay
above freezing Saturday night. Model guidance has trended upwards
slightly on QPF with amounts of a half to three quarters of an inch
north of the parkways with around an inch to an inch and a quarter
along the KY/TN border. This rain will be falling on melting snow
with the highest QPF`s falling on areas that receive the most snow
from Thursday`s event. Will be monitoring this closely as we`ve had
rivers already in or approaching flood from last weekends event.
There could even be so localized flooding concerns.
Early next week...
Quiet, drier and cooler weather will arrive
through the first half of next week. Highs will be in the 30s
Monday/Tuesday but warming into the mid/upper 40s by Wednesday.
&&
.Aviation...(00Z TAF Issuance)
Issued at 658 PM EST Wed Jan 5 2022
Impacts...Gusty winds tapering this evening, VFR now
through mid morning, then snow, low ceilings, and low vis through
late afternoon
Confidence: High on impacts and Med-High on timing
Things are quiet across the TAF sites at this hour, with any
lingering gusty winds expected to slacken over the next 1 to 3
hours. We`ll see high clouds filter in overnight, and they will
lower to around 8-12K feet by pre-dawn through early to mid morning.
Light snow is expected to begin around mid to late morning from W to
E, with pockets of moderate snow then expected through the
afternoon. In addition to the 1-3sm snows for much of the afternoon,
look for low MVFR (below 2 K feet) ceilings and a steady N wind.
Accumulating snow is likely on runways that are not maintained.
Snow tapers quickly from late afternoon to early evening with VFR
quickly returning thereafter. Look for a continued steady NW wind,
perhaps a occasionally gusty to around 20 mph.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Winter Weather Advisory from 10 AM EST /9 AM CST/ to 10 PM EST
/9 PM CST/ Thursday for INZ076>079-083-084-089>092.
KY...Winter Weather Advisory from 10 AM EST /9 AM CST/ to 10 PM EST
/9 PM CST/ Thursday for KYZ023>026-029>038-043.
Winter Storm Warning from 10 AM EST /9 AM CST/ to 10 PM EST /9
PM CST/ Thursday for KYZ027-028-039>042-045>049-053>057-
061>067-070>078-081-082.
&&
$$
Update...BJS
Short Term...RAS
Long Term...BTN
Aviation...BJS
Area Forecast Discussion
National Weather Service Marquette MI
658 PM EST Wed Jan 5 2022
.SHORT TERM...(This evening through Thursday)
Issued at 411 PM EST WED JAN 5 2022
The transition is slowly underway as the responsible low for
today`s snow keeps on trekking eastward. Tonight, LES will take
over, with NE flow dominating, although could waiver a bit to be
more Nrly as the night progresses, particularly in the western
portions of Upper Michigan. Given the trends and what`s
anticipated, have updated the headlines for counties impacted
under said NE flow, coupled with wind gusts that will cause
blowing snow, already underway in at least the Keweenaw Peninsula.
As advertised in yesterday`s discussion, what should be focused on
is the impacts as a result of the snow, not necessarily the
amounts in that snow will continue to accumulate rapidly in some
locations, particularly within the higher terrain spots within the
NE belts, but the impacts due to very poor visibilities, either
due to blowing snow or snow bursts (for lack of a better term
since want to make the distinction that heavy in this case is
veering away from wet and dense). SLRs are expected to increase
tonight as CAA pushes its way in post-lowpa.
Lows tonight will range from the single digits to teens, remaining
above zero, but wind chills will easily drop below zero for most
of the U.P. Temps will be moderated not only by the Great Lake of
Superior but from ongoing LES where it persists tonight. Highs
tomorrow though will run colder compared to today, topping out in
the teens nearly everywhere.
.LONG TERM...(Thursday night through Wednesday)
Issued at 321 PM EST WED JAN 5 2022
The big picture summary is that the ongoing long-duration snow event
comes to an end on Friday. A brief push of warmer air generates some
light snow Friday night into Saturday. Another arctic cold front
Saturday night delivers the coldest air mass of the season for early
next week. Northwesterly lake effect also appears virtually certain
from Sunday through at least Tuesday morning. A clipper moves
through Tues/Wed bringing some additional light snow and
invigorating LES. My preliminary guess is that a clipper pattern may
persist into mid-Jan so widespread heavy precip seems unlikely.
Ongoing upslope/lake-enhanced snow diminishes Thursday night into
Friday, but multi-band lake effect continues into Friday morning.
Lake-850mb delta-Ts still around 25C, inversions up to 6kft, and the
DGZ within the convective layer is supportive of heavy LES
wherever more dominant bands develop. LES is that environment
should be extremely fluffy and will pile up quickly. This
morning`s 12z HRRR indicates three dominant bands ongoing at 12z
Friday in Ontonagon County, near the MQT/Alger County line, and
eastern Alger/northern Schoolcraft Counties. All that is to say we
shouldn`t let our guard down going into Thursday night/Friday
morning, but bands do appear to be transient.
Winds rapidly back southwesterly pushing any remaining LES offshore
as the ridge axis shifts east during the day on Friday. A warm front
pushes north across our CWA Friday night resulting in a round of
light snow (less than 2") by Saturday morning. The possible
exception is the northern Lake MI shoreline - especially Schoolcraft
County - where S/SW flow lake enhancement may result in advisory
criteria amounts by Saturday afternoon. Meanwhile, a 50+ knot LLJ
moving through may result in gusty winds and potential for
blowing snow in the typical downslope locations near the Lake
Superior shoreline. However, at least one low/mid level inversion
limits mixing of the warmer air down to the surface and may limit
boundary layer wind speeds too.
Any warm-up realized on Saturday will be erased Saturday night into
Sunday as the next arctic cold front pushes southeast across the
CWA. Temperatures fall through the day on Sunday as 850mb temps cool
to at least -25C by 00Z Monday, which also instigates another round
of LES primarily for NW wind snow belts. The LES environment appears
to be too cold for fluffy snowfall, but sharp visibility reductions
should be expected in both falling LES and blowing snow too.
Elsewhere, extreme cold appears increasingly likely late Sunday
through Tuesday with wind chill headlines at least possible. EFI
values increased to ~0.7 for Tuesday morning low temps so there`s a
growing fraction of EPS ensemble members indicating extreme cold.
Looking further out, there may be a clipper on Tuesday/Wednesday,
but a trend toward less active weather seems likely by the second
half of next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 657 PM EST WED JAN 5 2022
Persistent lake effect snow will result in poor flying conditions
through tonight at all TAF sites. And, combined with the blowing
snow, flight conditions will predominantly be IFR/LIFR well into
tomorrow afternoon. The strong NNE winds will relax a bit at KIWD
early tonight, but do not expect any breaks in the wind at KCMX or
KSAW until tomorrow afternoon. Expect sustained wind speeds in the
12 to 14 kt range with gusts up to 30 kts. Conditions should start
to improve to MVFR/VFR late tomorrow afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 432 PM EST WED JAN 5 2022
NE gales to continue tonight, slowly slackening to less than
gale-force by tomorrow morning. Winds will remain elevated though
through much of tomorrow, finally dropping below 25 knots late
Thursday. The next time winds exceed 25 knots will be overnight
Friday into the weekend, with gales possible. Initially, winds
will predominately be Srly, but will become NWrly by the latter
half of the weekend. The winds will remain above 25 knots into
early next week, slackening off again by early Tuesday.
Heavy freezing spray also continues to prevail across the lake,
persisting well into tomorrow before finally dropping off in
intensity later in the day.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Storm Warning until 7 PM EST this evening for MIZ001-003-
084.
Winter Weather Advisory until 5 AM EST Thursday for MIZ006-007-
085.
Lakeshore Flood Advisory until 4 AM EST /3 AM CST/ Thursday for
MIZ001>007-009.
Winter Storm Warning until 1 AM EST /midnight CST/ Thursday for
MIZ002-009.
Winter Storm Warning until 7 AM EST Thursday for MIZ004-005.
Winter Weather Advisory until 7 PM EST /6 PM CST/ this evening
for MIZ010>014.
Lake Superior...
Heavy Freezing Spray Warning until noon EST Thursday for LSZ267.
Gale Warning until 3 AM EST Thursday for LSZ267.
Heavy Freezing Spray Warning until 11 AM EST /10 AM CST/
Thursday for LSZ162-266.
Gale Warning until 2 AM EST /1 AM CST/ Thursday for LSZ241>245-
249>251-263>266.
Heavy Freezing Spray Warning until 8 AM EST Thursday for LSZ244-
245-265.
Heavy Freezing Spray Warning until 2 PM EST Thursday for LSZ263-
264.
Gale Warning until 1 AM EST Thursday for LSZ246>248.
Heavy Freezing Spray Warning until 4 AM EST /3 AM CST/ Thursday
for LSZ240-241.
Gale Warning until 11 PM EST /10 PM CST/ this evening for LSZ162.
Heavy Freezing Spray Warning until 9 AM EST Thursday for LSZ251.
Lake Michigan...
None.
&&
$$
SHORT TERM...lg
LONG TERM...EK
AVIATION...TDUD
MARINE...lg
AREA FORECAST DISCUSSION
National Weather Service Morristown TN
1027 PM EST Wed Jan 5 2022
.UPDATE...
EVENING UPDATE.
&&
.DISCUSSION...
Overall, the forecast still remains on track with some minor
changes made based on recent model trends. Recent runs of the
HRRR, NAM, and RAP have trended the track of the surface low
further to the north with 30+ kts of southerly 850mb flow. This
could produce notable downsloping and may be problematic for
accumulations in portions of the eastern Valley/foothills.
Snowfall totals were lowered very slightly in these areas with the
same overall message. The next shift may make additional changes
when more global deterministic and ensemble data is available. In
any case, justification was present for the addition of Morgan
County into the warning as the combination of a sufficiently cold
column and deep moisture are maintained and even slightly enhanced
with these model runs. There has also been increasing indication
of a ~850mb warm nose reaching into southern portions of the area
that could cause more of a mixed bag of precipitation, given
sufficiently cold enough surface temperatures. This will be
another consideration for the overnight shift.
BW
&&
.AVIATION...
00Z TAF DISCUSSION.
VFR conditions are expected through the night before a system
impacts the region during the day and evening on Thursday.
Initially, precipitation will likely start as rain at CHA late in
the morning before spreading northward to TYS and TRI in the
afternoon hours. The current expectation is for a fairly quick
changeover to snow at those two sites with more of a prolonged
period of rain, snow, and possibly sleet mix at CHA. In any case,
visibility reductions to 1 mile or less are likely at each site
with potential for ceilings dropping to LIFR or even lower at
times. The worst of these impacts will likely be early to mid
afternoon for CHA and late afternoon into the evening at TYS and
TRI.
BW
&&
.PREV DISCUSSION...
/ISSUED 253 PM EST Wed Jan 5 2022/
SHORT TERM...(Today through Thursday Night)
Key Messages:
1. Rain/snow mix expected to begin Thursday morning in SE TN and
spread northeastward eventually transitioning to all accumulating
snow. Still uncertainty on the timing of this transition.
2. Very cold temperatures expected overnight Thursday night into
Friday morning
Discussion:
Currently slowly clearing skies as a weak front is moving through
and temperatures should climb up near normal, which will likely melt
off much of the remaining snow on the ground. Overnight with the
clearer skies we could see some patchy fog develop with temperatures
able to drop much lower and dew point depressions decrease.
Main weather impacts will begin on Thursday as a trough swings
through the southern Ohio Valley and a surface low moves through the
northern Gulf States, just south/east of the Appalachian Mountains.
In the Valley...
Reflectivities on radar may begin as early as 09-12z, but at that
same time the mid levels of the atmosphere will be pretty dry. So
the column is going to have to get saturated from the top down
before we really see precipitation at the surface outside of
flurries/drizzle. Model soundings saturate the column at CHA around
15-18z, around 18z at TYS, and around 21z at TRI. This is still one
of the more difficult aspects of the forecast as even just 30
minutes to an hour of lighter (heavier) precipitation will lead to a
slowing down (speeding up) of the onset of precipitation at the
surface. The combination of "when does the column saturate" combined
with "how warm do temperatures get up to during the day" makes for a
tricky forecast in the Valley. Think that it`s very likely we`ll see
sharp snowfall gradients even within a single county, and especially
counties with a variety of elevations. So overall confidence in
snowfall amounts and timing is lowest in the Valley. High resolution
models have speed up how fast the precipitation exits the region,
especially during the 00-06z timeframe as the shortwave picks up
speed. This quicker exit of precipitation will definitely impact how
much snow accumulates as this 00-06z timeframe is the best for the
ground and atmosphere to create snow accumulations at the surface.
So have lowered snowfall amounts in the southern and central valley
during this time period by a decent amount, and to a lesser degree
amounts have lowered in northeast TN and southwest VA. Precipitation
should exit to the northeast of the Valley by 03-09z.
There is a small window during the transition of snow to rain that
we could see a wintry mix with ice pellets or freezing rain, mainly
in southwest TN. Window for this transition looks to be pretty
short, and hopefully if any does occur the liquid rain that falls
after any frozen rain would melt it away and keep impacts to a
minimum.
Cumberland Plateau and Southwest VA...
Confidence is a bit higher on the Plateau, over into southwest
Virginia as there is a smaller window for a rain/snow transition.
Due to this expect snowfall totals to be higher as the predominant
precipitation type should be snow. Some places will switch back over
to a rain/snow mix, but higher elevations have the best chance to
see the most snowfall accumulations. The current Winter Storm Watch
will be upgraded to a winter storm warning for the plateau over into
southwest Virginia. Think that locations along the
Virginia/Kentucky/West Virginia borders will possibly see the
heaviest snowfall with the highest elevations possibly seeing 6+
inches over a fairly short period Thursday into Thursday night.
Southern Appalachian Mountains...
Tricky in the mountains due to the extreme elevation differences,
but as usual expect the higher elevations to receive more snowfall
with colder temperatures and a higher snow to liquid ratio. Could
see 6+ inches at the tops of the mountains, transitioning down to
closer to 2-3 inches in the foothills. There is less moisture and
upper level dynamics over the mountains, so they very well may see
less snow than parts of southwest VA.
Friday Morning...
With most of the snow looking like it will come to an end fairly
quickly Thursday night. What you see on the ground when the snow
ends will stay on the ground overnight with temperatures through
Friday morning expected to be the coldest we`ve seen in over a year.
Low temperatures in the teens, and even in the single digits are
expected, and even with light winds of around 5-10 mph wind chills
will drop into the single digits in most locations, and possibly
below zero in the higher elevations.
ABM
LONG TERM...(Friday through Wednesday)...
Key Messages:
1. Lingering snow expected to persist on the ground into/through
Saturday morning amidst well below normal temperatures.
2. Dry on Saturday with increasing precipitation chances
Sunday/Monday as the next frontal system passes through.
3. Below normal Tuesday, warming through weeks end.
Discussion:
The long term fcst period kicks off on Friday morning amidst the
passage of a deep longwave H5 trough favoring nw flow across the
region, with cold/dry surface high pressure to settle in. Won`t
rule out a few lingering upslope snow showers across the northern
and highest peaks of southwest VA, but that should taper quickly
into midday Friday, all while temperatures remain below freezing for
most locations north of I40 throughout the day. South of I40, am
expecting slightly warmer temperatures, generally at or slightly
above freezing. All that said, most any snowfall will be
reluctant to melt, especially early/mid Friday as sky cover
gradually scatters. Therefore would expect roadway impacts through
Friday with black ice being a possibility Friday night with any
overnight refreeze. By Saturday, the deep ridge shifts east with
the surface high over the Carolinas. This will foster clear skies
and returning sly flow favoring max temperatures in the 40s/50s
which will support good melting.
Moving into Sunday, the next upper wave will dive southward
across the northern Rockies and amplify the mean longwave H5 flow
with deepening troughing out west and ridging along the east
coast. With falling heights rapidly approaching early Sunday
morning amidst isentropic ascent in the llvs ahead of Gulf Coastal
low pressure, will favor increasing pops, possibly yielding a
brief period of rain/snow in the northern valley/mountains
(little/no accums) before warm advection fosters all rain. Pops
will remain elevated through Sunday night as the cold front drives
east ahead of the upper trough axis, possibly with a change over
back to rain/snow along/behind the front overnight into Monday
morning as the upper trough axis shifts through, prompting deep
caa. By midday Monday the upper trough and any remnant moisture
will have shifted east of the Appalachians with deep nwly flow to
prevail aloft with temperatures cooling back to near/below normal
through Tuesday. This pattern will prevail into midweek (per
ensemble height fields) with quiet a bit of uncertainty in the
pattern late week.
CDG
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 32 39 17 36 23 / 10 80 20 0 0
Knoxville McGhee Tyson Airport, TN 29 38 14 31 18 / 0 80 40 0 0
Oak Ridge, TN 26 37 13 31 18 / 0 80 30 0 0
Tri Cities Airport, TN 27 39 13 27 14 / 0 80 70 0 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Winter Weather Advisory from 10 AM Thursday to 1 AM EST Friday
for Cherokee-Clay.
TN...Winter Storm Warning from noon Thursday to 7 AM EST Friday for
Blount Smoky Mountains-Campbell-Claiborne-Cocke Smoky
Mountains-Hancock-Johnson-Morgan-Scott-Sevier Smoky
Mountains-Southeast Carter-Southeast Greene-Southeast
Monroe-Unicoi-Union.
Winter Weather Advisory from 10 AM EST /9 AM CST/ Thursday to 1
AM EST /midnight CST/ Friday for Bledsoe-Bradley-East Polk-
Hamilton-Loudon-Marion-McMinn-Meigs-Northwest Blount-
Northwest Monroe-Rhea-Roane-Sequatchie-West Polk.
Winter Weather Advisory from noon Thursday to 7 AM EST Friday
for Anderson-Grainger-Hamblen-Hawkins-Jefferson-Knox-North
Sevier-Northwest Carter-Northwest Cocke-Northwest Greene-
Sullivan-Washington.
VA...Winter Storm Warning from noon Thursday to 7 AM EST Friday for
Lee-Russell-Scott-Washington-Wise.
&&
$$
Area Forecast Discussion
National Weather Service Nashville TN
939 PM CST Wed Jan 5 2022
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Evening Update Summary: Latest model guidance has been coming in
with more snow compared to previous runs, so updated snow amounts
upward slightly to line up with this trend. Upgraded the areas
most likely to see heaviest snow with a winter storm warning this
evening, mainly north and east of Nashville. If next batch of
model guidance continues the trend of higher snowfall totals, the
warning could be expanded further overnight. The NAM remains most
concerning with freezing rain/ice potential in the south near the
AL border, especially the southwest counties, where around a tenth
of an inch or a little more will be possible. More below.
Models have been consistent with the track of the upper trough and
surface low in recent runs. All models showing strong isentropic
lift and moisture advection tomorrow morning ahead of the low
helping to erode the dry layer aloft. Strong Q vector convergence
as well as decent frontogenesis signatures aloft show the
potential for heavy snow, as well as strong omega values in the
800-600mb layer from mid morning through the afternoon. But, the
GFS/ECMWF are colder at 850 mb in the south late Thursday morning,
and the NAM holds on to the warm nose and as of the 00Z run, the
NAM has nearly 5C at 850 mb in the southwest and near the AL
border counties. This would indicate more of a threat for freezing
rain and sleet in that area, and even some ice accumulation
around a tenth of an inch or more. If the GFS/ECMWF come in
warmer for that area, there may be a need for a winter storm
warning in the south for ice accumulations at or over a tenth of
an inch, with less snow accumulation than the rest of the mid
state.
As for the snow trends, CAMs have been showing the highest
increase in snow amounts, especially the HRRR and NAMNest/NamDNG.
They have been showing more bands of heavier snowfall from around
Perry County through Robertson County NW of Nashville up to around
6 inches. With a dynamic system we have in place tomorrow, there
is the potential for mesoscale snow bands that put down good
snowfall rates in a short amount of time, but for now, leaning
more towards the average and large scale models and giving
widespread 2 to 4 inches, and amounts up to around 5 inches near
the KY border and higher elevations on the Plateau. Should the
upward trend continue in the models with snow,the winter storm
warning area will likely be expanded, and more widespread amounts
of 3 to 4 inches will be likely.
What makes this event different? Cold air is already on its way
to the mid state this evening, so rather than chasing cold
temperatures with remaining moisture at the end of a system for
our typical winter events, we will be starting the event in the
upper 20s/low 30s. Strong moisture advection will help with the
drier air initially, and all models are on board with strong
southerly flow in the low levels off the surface bringing in
plenty of moisture ahead of time. The chances for getting at least
2 inches or more with current model data is very high, and even 3
inches or more is high for the northern 2/3 of the mid state
especially in the warning area. Stay tuned for updates overnight.
&&
.AVIATION...
00Z TAF DISCUSSION.
Mostly clear skies will give way to a gradually lowering cloud
deck during the overnight hours, with borderline MVFR CIGS around
12Z. Light snow is expected to begin falling around this time, and
by 15Z-16Z all TAF sites will likely be impacted by IFR VIS and
CIGS as the snow intensity picks up. This should last for the
remainder of the TAF period, though possible amendments for LIFR
conditions may be possible with the heaviest snowfall.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 9 AM to 9 PM CST Thursday for Clay-
Cumberland-De Kalb-Fentress-Jackson-Macon-Overton-Pickett-Putnam-
Robertson-Smith-Sumner-Trousdale-Van Buren-White-Wilson.
Winter Weather Advisory from 4 AM to 4 PM CST Thursday for
Bedford-Cannon-Cheatham-Coffee-Davidson-Dickson-Giles-Grundy-
Hickman-Houston-Humphreys-Lawrence-Lewis-Marshall-Maury-
Montgomery-Perry-Rutherford-Stewart-Warren-Wayne-Williamson.
&&
$$
DISCUSSION......Barnwell
AVIATION........05
Area Forecast Discussion
National Weather Service Paducah KY
549 PM CST Wed Jan 5 2022
.UPDATE...
Issued at 549 PM CST Wed Jan 5 2022
The AVIATION section has been updated for the 00Z TAF issuance.
&&
.SHORT TERM...(Tonight through Thursday night)
Issued at 245 PM CST Wed Jan 5 2022
Main focus is the snowfall forecast Thursday. Models continue to
advertise a fast moving mid level wave will track across the area,
and strengthen as it does. We once again coord with WPC and
surrounding offices on final QPF and amounts, and maintained a
slightly higher SLR than what the NBM has. We think the snow will
move into SEMO and southern IL by 6 to 8 a.m. and spread rapidly
east through the morning, ending in the afternoon across the
Kentucky Pennyrile region. We tend to favor the lower res
deterministic models and the 12z HRRR which lines up with them,
for our QPF and snow forecast. Slightly higher amounts spell down,
supported by the dynamic nature of this wave.
As a result we have a Winter Weather Advisory now in effect for
most of the area. The area from the LBL over to Hopkinsville
should have the best chance for impacts and higher snow totals. 2
to 3 inches in this area with isolated 4 possible, lowering to 1
to 2 with local 3 just west of there. Up along I-64 in southern IL
and back into the Ozark Foothills, amounts should stay down at 1
inch or less. Dry weather returns for Thursday night, with very
cold wind chills in the single digits to a few degrees below zero
likely Friday morning.
.LONG TERM...(Friday through Wednesday)
Issued at 245 PM CST Wed Jan 5 2022
The long term forecast period begins with an upper-level trough over
the Eastern U.S., a ridge over the Mountain West, and northwesterly
flow across the Quad State. High pressure to our northwest will
steer cold Canadian air into the area, resulting in a very cold
morning with early morning lows Friday in the 5-15 range with the
lower values to the northeast and wind chills on the order of 10
degrees lower.
Progression of the upper trough eastward will allow 500 mb heights
to increase and ridging to build into the area. With the high
pressure moving through, winds will shift clockwise to southerly by
Saturday. A significant warmup is anticipated with highs in the 40s
Saturday. Moisture from the Gulf will be brought towards the Lower
Mississippi River valley as a cold front develops across the Plains.
Rain moves into the Quad State from the southwest Saturday afternoon
and continues through the night into Sunday morning. A few
thunderstorms will be possible Saturday night, mainly in southern
portions of the Quad State, but no severe storms are anticipated.
Quad State QPF nudged up about 10-15% this model cycle to around a
third of an inch for the northwestern portions to a little over an
inch for the KY Pennyrile. With +2 standard deviation precipitable
water values, this increase seems reasonable. The cold front
approaches from the northwest near sunrise Sunday which will result
in early morning highs for northwestern Quad State and midday highs
for locations in the southeast.
Cold temperatures return following Sunday`s cold front. With lows
mainly in the 15-20 range, at the moment the early Monday morning
time frame does not appear to be quite as cold as early Friday
morning. Dry weather is expected Sunday night through Tuesday, with
a warming trend to near average temperatures for midweek. Split flow
develops over the mountain west early in the week and it is
uncertain whether the northern or southern storm track could bring a
system to the area midweek where the branches merge.
&&
.AVIATION...
Issued at 549 PM CST Wed Jan 5 2022
An area of light snow will move through the region Thursday. A 2
to 5 hour period of IFR snow with MVFR ceilings can be expected,
with the longest duration and lowest conditions expected over west
Kentucky, mainly to the south and east of KPAH and KOWB. In
general the snow will begin from west to east across the region
12Z to 15Z, and end from 16Z to 20Z. Conditions should improve to
VFR quickly after the snow ends. Northwest winds will
occasionally gust 15-20kts through the period.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Winter Weather Advisory from 6 AM to 4 PM CST Thursday for
ILZ081>094.
MO...Winter Weather Advisory from 6 AM to 4 PM CST Thursday for
MOZ087-109>112-114.
IN...Winter Weather Advisory from 6 AM to 4 PM CST Thursday for
INZ081-082-085>088.
KY...Winter Weather Advisory from 6 AM to 4 PM CST Thursday for
KYZ001>007-010-014-015-018>020.
Winter Weather Advisory from 9 AM to 7 PM CST Thursday for
KYZ008-009-011>013-016-017-021-022.
&&
$$
UPDATE...DRS
AVIATION...DRS
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
915 PM EST Wed Jan 5 2022
.SYNOPSIS...
A weak cold front will move through the region tonight with weak
high pressure following on Thursday. A strong cold front will move
east through the area on Thursday night. Cold Canadian high pressure
will build into the region for Friday into Saturday. Another cold
front approaches on Sunday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 915 PM Wednesday...
The most noteworthy weather overnight will be low clouds and fog
over eastern sections. The latest surface map shows a lingering
frontal zone just off the Outer Banks, drifting slowly eastward,
with a narrow ridge extending over the eastern Carolinas from the
SW, a trough extending from the interior Mid Atlantic SSW through
the western Carolinas, and the incoming cold front stretching from
the E Great Lakes through the Ohio Valley, central TN, and the lower
Miss Valley. High clouds continue to stream SW to NE over our far N
sections into VA, within fast cyclonic southwesterly mid level flow
over the Ohio Valley, interior Mid Atlantic, and Northeast. An area
of fog/stratus over E NC (including our far E sections), fostered by
the weak flow and higher dewpoints within the surface ridge, has
drifted slowly E over the last few hours, its westward edge doing
battle with an influx of drier 925 mb air within slowly veering flow
from the west. As this weak surface flow persists overnight and
expands a bit westward, we should continue to see this meandering of
fog/stratus overnight over our E sections, mostly over the Coastal
Plain into the far E Sandhills, while high thin clouds will persist
across the north, expanding S and E overnight as a strong shortwave
trough swinging through the E Great Lakes and St Lawrence Valley
nudges the mid and upper level jet core eastward. Earlier forecast
temps are on track with observations, so still expect lows in the
30s, coolest in the far W Piedmont near the Yadkin Valley. -GIH
Earlier discussion: Aside from a small area of stratus east of I-85,
morning low clouds have scattered to clear or some high based strato
cu and temps have risen into the 50s. Given that the low-level
moisture in the coastal plain has lingered well into the afternoon,
it may linger into the overnight hours as the boundary layer cools.
Meanwhile, a shortwave rotating through the longwave trough will
cross the OH Valley/great Lakes tonight, with a trailing weak cold
front that cross the mountains and slip into the area. Other than
some jet induced mid-high clouds there will be little impacts from
the front. Some guidance suggests patchy fog in the southern
Piedmont ahead of the front where the slp gradient will be weakest.
Lows in the low to mid 30s.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 300 PM Tuesday...
Increasing confidence in only a brief changeover from rain to snow
across the northwest and northern Piedmont Thursday night and very
little impact...
Tonight... The weak cold front that will settle into the area
tonight will lift back to the north and west on thursday in response
to shortwave digging through the central Plains. Should see a
modest rebound in temps again into the mid 50s under mostly sunny
skies.
Thursday/Thursday night... Rain will begin to spread into the
western Piedmont by late afternoon/evening as the shortwave swing
into the TN valley and an area of low pressure develops over the
lower MS Valley region and tracks northeast along the front. Rain
will continue east through the Piedmont and coastal plain between
roughly 00Z and 09Z while the surface low tracks roughly from
Upstate SC to the Tidewater region of VA.
QPF continues to be relatively light on the order of a couple tenths
of an inch or less in the northwest Piedmont, with lesser amounts to
the south and east. Models are fairly consistent at this point.
The big question continues to be whether or not there will be a
transition to snow across the northwest and northern Piedmont areas.
Latest forecast soundings in the Triad show only an hour or two when
there is saturation up to or above -10C and there is sufficient
boundary layer cooling toward freezing to support a changeover, as
post-frontal airmass is very cold/dense (back trajectories to
International Falls, MN this morning) and may struggle to get across
the mountains as quickly forecast. In fact the 12z HRRR run which
now extends through Thursday night appears warmer in the boundary
layer as the precip is ending. With these factors and light
qpf/rates, any accumulation would be less than an inch and on
elevated surfaces there still appears to be little impact from this
brief event. Changes to the forecast are minimal today.
As the precip departs the area by 12z, temps will be crashing into
the 20s and lower 30s with clearing. drying northwest winds should
help, but there could be some black ice issues early friday morning
given the rapid cooling immediately following the precip.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 355 PM Wednesday...
Behind the cold frontal passage, cold Canadian surface high pressure
will build into the area from the west on Friday and Friday night.
This will result in cold, dry weather and mainly clear skies, along
with blustery NW winds during the day from the pressure gradient
between the high pressure system and a deepening low off the New
England coast. With low-level thicknesses only around 1270-1290 m
and strong CAA, highs on Friday will only reach the mid-to-upper-30s
in the far northern Piedmont, with lower-to-mid-40s elsewhere. As
high pressure moves overhead on Saturday morning, good radiational
cooling from clear skies and light winds will result in some of the
coldest temperatures so far this season, in the mid-teens to lower-
20s.
As the high moves east and off the coast on Saturday and Sunday and
a cold front approaches from the west, the surface flow will switch
to a southerly direction, resulting in warming temperatures through
the weekend especially by Sunday. Highs on Saturday will still be
slightly below normal (generally in the 40s) with lows Saturday
night in the upper-20s to lower-30s. Sunday`s highs will be well
above normal, in the 50s and 60s, with skies turning overcast. The
cold front will then cross central NC late Sunday night and early
Monday morning. With decent height falls and PW values around 1.25-
1.50 inches, models are in good agreement that it will have enough
moisture for a band of showers to move across the area. Thus have
categorical POPs during this period. Total expected rainfall is in
the half inch to inch range, highest in the south and east.
Temperatures look warm enough for all liquid precipitation from this
event.
Strong Canadian surface high pressure will build in from the west
behind the front. Thus skies will quickly clear and temperatures
will turn sharply colder once more on Monday with blustery NW winds.
Highs will mainly be in the 40s, with lows in the upper-teens to mid-
20s on Monday night. Temperatures on Tuesday will struggle to get
out of the upper-30s to lower-40s as the high moves overhead, before
temperatures may start to warm to near normal on Wednesday as the
high begins to move east.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 745 PM Wednesday...
Widespread cloudiness associated with a departing system have exited
most of central NC. However, lingering low level moisture combined
with mainly clear skies and light winds has resulted in the
development of low stratus and fog across portions of the Coastal
Plain, eastern Piedmont and portions of the Sandhills. Guidance is
quite varied, but confidence is growing that IFR to LIFR CIGS and
visibilities will become more widespread and spread to the west and
north across much of central NC with the exception of the Triad
where lower dew points should limit clouds/fog. Restrictions will
likely vary overnight as an approaching front could produce a little
more mixing and wind resulting in more stratus then fog at times.
The lowest CIGS and VSBYS are likely across the Coastal Plain
impacting the KRWI terminal. Conditions should improve after
daybreak on Thursday as a cold front arrives with somewhat dryer air
and mixing. As another storm system approaches, high and mid clouds
will increase during the afternoon from the northwest. Light
southwest winds tonight will stir at times overnight but remain less
than 6kts with some locations, especially in the east, going calm
for periods. Winds will become light northwest on Thursday morning
before quickly veering around to light southeast by Thursday
afternoon.
Looking ahead: An area of low pressure will bring a period of sub-
VFR conditions with clouds and some rain on Thursday night. VFR will
conditions will return on Friday with some gusty winds. Fair weather
will continue into Saturday night. Another cold front will move
through the area with some LLWS possible Sunday morning and sub-VFR
conditions on Sunday afternoon into early Monday with improving but
gusty condition`s late Monday. -Blaes
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Blaes
NEAR TERM...Hartfield/Smith
SHORT TERM...Smith
LONG TERM...Danco
AVIATION...Blaes