Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/03/23
Area Forecast Discussion
National Weather Service Burlington VT
1016 PM EST Sat Dec 2 2023
.SYNOPSIS...
Dreary weather with drizzle and fog will continue into Sunday
morning as a stationary front lingers across the region.
Temperatures will begin to cool tonight, resulting in the potential
for areas of freezing drizzle in parts of northern New York and
Vermont, with any ice accretion limited to untreated overpasses and
elevated surfaces. Then, a stronger system is expected to impact the
region Sunday afternoon through Monday. Several inches of heavy, wet
snow are expected for much of the region except for the lowest
valleys. Conditions will trend cooler, with intermittent periods of
showers as we head into mid week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 959 PM EST Saturday...Widespread mist and fog is being
reported throughout the area, with visibilities reduced as low
as 1/4 mile in some places. Expect the dense fog and mist to
persist through the night, making for difficult travel.
As latest 00Z suite of guidance begins to come in, noting an
upward trend in snowfall amounts area-wide for the Sunday/Monday
system. NAM3, GEM Regional, and RAP all showing a transition to
heavy wet snow at all elevation levels including the valleys for
at least a few hours Sunday night. If these trends hold, may
need to expand winter headlines with the overnight forecast
package and adjust snowfall total forecast accordingly. One
particular challenge will be the Saint Lawrence Valley, where
sub freezing air will be pulled down from the northeast and
models are showing a sharp cut off between 6-12+ inches of snow
over the northern valley (could be north or south of the
International Border) and just a couple of inches further south.
Lining up where this gradient sets up will be one of the
forecast challenges tonight. A similiar challenge will present
in the northern Champlain Valley, with models bringing
accumulating snow further south as we get closer to the event.
Will wait for the full suite of 00Z guidance to come in and
adjust forecast as necessary. Previous discussion follows...
We`re finally seeing some gradually improving conditions across
the region this afternoon, with area webcams and surface obs
starting to indicate slowly increasing visibilities. The
steadier light precipitation will continue to taper off through
the remainder of the afternoon into the evening, as well.
However, ample low level moisture will linger overnight into
Sunday morning. As such, periods of drizzle and fog are
expected. Temperatures will fall only slightly tonight, but it
should be enough for some portions of northern NY/VT to drop to
near or below freezing. As such, freezing drizzle will be
possible late tonight/early Sunday. Road temperatures are mainly
in the upper 30s to low 40s, so any ice accretion should be a
glaze and mainly limited to elevated surfaces and untreated
secondary roads. Lows tonight will range from the upper 20s in
the usual cold spots to the mid 30s in the southern Champlain/St
Lawrence Valleys.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 331 PM EST Saturday...A Winter Weather Advisory is in effect
from 1 pm Sunday to 7 am Tuesday for the Adirondacks and all of
eastern VT east of the Greens, and the spine of the south central
Greens. Main concern is heavy wet snow, leading to hazardous travel
and possible scattered power outages. Snow totals during this time
of 3 to 8 inches will be possible, with locations above 1500
receiving up to 10 inches. Lower elevations will mainly get 1-3
inches, with the valley floors an inch or less.
Patchy drizzle/freezing drizzle will likely be ongoing Sunday
morning, but widespread precipitation will quickly spread from
southwest to northeast Sunday afternoon. This is yet another tricky
precipitation-type forecast as once again, boundary level
temperatures will hover very close to freezing. However, a perusal
of the latest hi-res guidance indicates most areas below 1500 ft
will start out as rain, perhaps briefly mixing with snow at the
onset. Overall expect just rain/snow, though can`t rule out very
brief periods of sleet during any transition. Also, with northeast
wind in the St Lawrence Valley, there`s a very real possibility that
locations like KMSS may hold onto shallow sub-freezing temperatures
for a few hours after onset; have added a chance of freezing rain to
the northern St Lawrence accordingly, with perhaps a hundredth or
two of ice accretion. Otherwise, rain will mix with and change over
to snow at higher elevations through Sunday afternoon, with
locations AOA 1000 ft likely all snow by the evening. We could see a
pretty good warm-advection thump of snow during the
evening/overnight as low pressure lifts along Lake Ontario and
through the St Lawrence Valley. Snowfall rates may briefly approach
1 inch/hr, especially at higher elevations. Areas along/east of the
Greens and in the northern Adirondacks will likely pick up 2-6
inches overnight; with southeast flow, upslope along the eastern
side of the higher terrain will allow greater amounts to focus in
the favored locations. Even valley locations could pick up some
slushy accumulation overnight. With temperatures near to just above
freezing, t he snow will be heavy and wet, with ratios 8-10 to 1,
which may bring down some branches, resulting in scattered power
outages. Travel will likely be difficult overnight, along with the
Monday morning commute.
The low will drift along the international border on Monday, and
much of the guidance shows drier air spilling into the region. We
should see a brief break in the steadier precipitation for a bit
during the mid-late morning hours, but as the low and its associated
upper shortwave drift over the region Monday afternoon and evening,
showers will reinvigorate, especially over the higher terrain.
Temperatures will warm slightly during the first part of the day, so
again expect valley locations to see mainly rain, with rain/snow in
the higher terrain. However, colder air will start to funnel into
the region Monday evening and night as the upper shortwave traverses
overhead. This will also help to make the snow lighter and fluffier
in nature for the remainder of the event, with snow ratios more on
the order of 12-15 to 1. Winds will turn toward the west, so while
any rain turns back into snow, precipitation will also become more
focused along the western slopes of the northern Adirondacks/Greens.
This activity will persist much of the overnight period. Lows will
be in the 20s areawide.
Winds not looking like too much of an issue for this event as the
strongest winds aloft will move through during the steady
precipitation, limiting mixing. There could be some briefly higher
gusts Sunday afternoon on the western sides of the Adirondacks and
Greens due to downsloping of southeast flow, with perhaps some gusts
up to 30 mph. Overall though, expect the windiest conditions to
remain limited to summit level, where winds of 25-35 mph with higher
gusts will be possible.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 331 PM EST Saturday...Overall the weather looks much quieter
for the rest of the week with no large scale impactful systems to
worry about. Upslope snow showers mainly across the higher terrain
will continue through Tuesday night, slowly waning during the
period, and eventually ending on Wednesday as a weak ridge of
surface high pressure builds into the region for Wednesday night. A
weak shortwave may bring some light snow showers to portions of
western New York on Thursday, but the next best chance for
precipitation comes as a weak clipper-type system will look to skirt
the international border late Friday into Saturday. Thermal profiles
mainly snow, though with some rain mixed in during the day in the
broader valleys. Overall, not a big event by any standards with
modeled QPF generally less than 0.2". Temps through the period will
remain below normal for for early December through Friday with highs
upper 20s to mid 30s, and lows teens to 20s.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Through 00Z Monday...Low stratus clouds will remain overhead
with little to no improvement expected through the next 24
hours. Expect widespread and persistent IFR/LIFR ceilings with
mist and fog that will reduce visibilities to LIFR through MVFR
levels. Visibilities may be more variable overnight than
ceilings, with brief improvements in vis possible at times, but
low clouds should stay persistent and keep overall LIFR/IFR
conditions in place. Some patchy freezing drizzle is possible
overnight, especially at higher elevations over northern New
York. Some surfaces may be slick.
A winter storm will move into the area tomorrow into tomorrow
night. Precipitation will start as predominantly rain after 18Z,
but will changeover to snow through 00Z especially at higher
elevations. After 00Z, beyond this 24 hour TAF period, expect
heavy wet snow at times with very low ceilings and visibilities,
especially in higher terrain TAF sites.
Winds will be light and variable through the night, becoming
southeast under 10 kt after 12Z. The exception will be KMSS,
which will see some northeast winds, gusty at times to 20 kt.
Outlook...
Sunday Night: Mainly MVFR, with areas IFR possible. Definite SN,
Definite RA.
Monday: Mainly MVFR, with local IFR possible. Likely SN, Chance
RA.
Monday Night: Mainly MVFR, with local IFR possible. Chance SN.
Tuesday: Mainly MVFR, with local VFR possible. Slight chance
SHSN.
Tuesday Night: Mainly MVFR, with local IFR possible. Slight
chance SHSN.
Wednesday: Mainly MVFR, with local IFR possible. Slight chance
SHSN.
Wednesday Night: Mainly VFR, with areas MVFR possible. NO SIG WX.
Thursday: Mainly VFR, with areas MVFR possible. Slight chance
SHSN.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Weather Advisory from 1 PM Sunday to 7 AM EST Tuesday
for VTZ003-004-006>008-010-018>021.
NY...Winter Weather Advisory from 1 PM Sunday to 7 AM EST Tuesday
for NYZ030-031-034.
&&
$$
SYNOPSIS...Hastings
NEAR TERM...Duell/Hastings
SHORT TERM...Hastings
LONG TERM...Lahiff
AVIATION...Duell
Area Forecast Discussion
National Weather Service Columbia SC
720 PM EST Sat Dec 2 2023
.SYNOPSIS...
A wave of low pressure will move northeast from the Gulf of
Mexico into the Southern Appalachians through tonight and early
Sunday, providing a chance for showers. Drier air will enter
northern areas Sunday afternoon, while central and southern
areas will see a chance of showers and isolated thunderstorms
Sunday ahead of a weak front that will come through Sunday
evening. Expect drier and slightly cooler air for Monday, under
breezy conditions. Continued dry with near normal temps Tuesday.
A dry cold front will come through Tuesday night, and bring in
cooler air for Wednesday and Thursday, with breezy conditions
possible again Wednesday. Expect fair weather with a gradual
warming trend Friday and Saturday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Widespread cloud cover remain across the region currently as
plenty of mid and upper level moisture streams northeastward
across the area. We are southeast of a 300 hPa jet streak (that
really hasn`t moved much in 24h) on the order of 120-130 kts per
RAP Mesoanalysis. This implies plenty of upward motion for at
least clouds, and you`d think precip. However, we just merely
have clouds! We were stuck in a classic FL Panhandle-Moisture-
Robbery scenario, where intense convection developed last night
(as hi-res guidance had been indicating for at least 36h) and
persisted throughout the day today. So while we have a good
synoptic setup for precip, we just did not get the moisture flux
that we expected. PWs are slightly above normal at 1.3-1.5"
across the FA, but not close to the 250% of normal that
ensembLes had been indicating in the days 3-5 range. Upstream,
there is little rain, and belief is very low that we`ll actually
see many showers tonight. Have decided to basically cut PoPs
across much of the area overnight tonight as a result, only
increasing them again towards morning as the actual cold front
approaches from the west. Lows tonight will be fairly close to
where they are now - in the low to mid 60s under cloudy skies.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Mean upper trough axis to remain over the central CONUS with a
SW flow aloft remaining for our region Sunday. Surface wave of
low pressure will be moving farther off to our NE, with a
trailing front to come through Sunday evening. Drier air, with
lower PWs, will enter northern areas late Sunday afternoon.
Across mainly the southern half of the forecast area (FA),
moisture and weak instability will provide for a chance of
showers, and possibly isolated thunderstorms. Drier air to
continue filtering in Sunday night and Monday. The air mass
behind this front/trough is not very cool, and with a continued
SW flow aloft, it will take a while for the cooler air to make
its way over the mountains. As a result, though lower than
Sunday, max temps Monday forecast to still be above normal. An
upper trough and surface low will move east across the Ohio/TN
Valley to the Central Apps Monday, with a trailing reinforcing
dry cold front to approach. The surface pressure gradient
between these features, and surface high pressure over TX, may
result in breezy conditions Monday. A Lake Wind Advisory may be
required.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Upper trough will dig SE from the Mid Miss/Ohio Valley across
the Carolinas Tuesday/Tue nt/early Wed, with a dry reinforcing
cold front coming through late Tue nt. This system will not have
any significant moisture to work with, with PW values 0.5 inch
or lower. Low pressure expected to develop off the Mid Atlantic
coast Wednesday, with surface high pressure still well to our
west. Resulting increasing surface pressure gradient may result
in breezy conditions possible again Wednesday. Behind this front,
some Canadian air will bring in cooler temps, with temps
falling below normal, and surface high pressure building into
our region, or just to our south, Wed nt/Thu. Upper trough to
shift to our east Thursday through Saturday while an upper
trough shifts east into the Rockies, with some rising upper
heights and weak upper ridging over our region. A front appears
will remain stalled to our north, which may possibly back door
down the eastern seaboard. PW values progged to remain below
normal through at least Friday. Gradual air mass modification to
result in temps trending upward. Current indications are that
an approaching weather system and increasing moisture could
affect our region just beyond the current forecast period, for
next Sat nt/Sun.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
MVFR cigs expected to overspread the region at the beginning of
the forecast period with deteriorating conditions overnight with
increasing southerly flow ahead of an approaching cold front.
Guidance is mixed as to how low cigs will go IFR or LIFR but has
trended to improved conditions so forecasted IFR cigs to develop
after 04z-06z except at OGB where it should be delayed until
around dawn. Some passing showers possible but do not expect
them to be strong enough to result in much vsby restrictions and
should be short lived. After 12z Sunday, ceilings will be slow
to improve as a cold front will be approaching from the west
and scattered showers are expected as the front approaches
during the 15-18z period Sunday. Skies should improve by
afternoon as drier air works into the region. Winds will pick up
with the front from the southwest around 10 knots with gusts up
to 20 knots at times and direction shifting to the west late.
EXTENDED AVIATION OUTLOOK...Prevailing VFR conditions develop
by Sunday Night behind the front lasting through Thursday.
Breezy conditions possible Monday and Wednesday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
447 PM MST Sat Dec 2 2023
.SHORT TERM...(Today through Monday)
Issued at 230 PM MST Sat Dec 2 2023
Current IR Watervapor loop shows the first of a series of upper
level shortwaves near the Wyoming and Nebraska border at this
time. This feature will exit to the east into central Nebraska
this afternoon. Other than significant mountain snowfall, not
much impact for most of southeast Wyoming and western Nebraska
with some flurry/snow shower activity earlier today. Seasonable
cold temperatures will continue today and tonight with
northwesterly flow aloft on the western side of the shortwave.
Winds have not been too bad so far today with gusts mainly
between 35 to 45 MPH. However, expect this to change as we head
into tonight.
Winter Storm Warnings for the mountains look good, with several
SNOTEL sites already verifying Winter Storm snowfall criteria.
Expect this to continue tonight and Sunday after a brief lull
this evening ahead of the next upper level shortwave trough. No
changes made to the current winter headlines, although we need
to watch the Northern Snowy Range foothills (Arlington/Elk
Mountain) for enhanced snowfall rates late tonight through early
Sunday and very strong winds which may create areas of blowing
snow. Expect the main impact to be strong gusty winds, but will
continue to monitor for snow and blowing snow impacts tonight
and Sunday. Otherwise, will likely see several feet of snow for
portions of the Sierra Madre Range into early next week with 1
to 2 feet of snow for the higher elevations of the Snowy Range.
Models show the next upper level shortwave trough quickly moving
southeast across Wyoming late tonight and east into Nebraska by
midday. Expect winds to increase this evening across most of
southeast Wyoming where High Wind Warnings remain in effect.
There is some uncertainty with precipitation and its affect on
low level winds. Although low level subsidence is strong
initially, models show precipitation loading becoming an issue
after midnight towards sunrise. Last few runs of the HRRR show
a band of steady snowfall across much of the I-80 corridor and
into I-25 corridor as the potent trough axis quickly moves
northwest to southeast over central Wyoming. Quite a bit of
forcing, although brief, with this feature and would not be
surprised if downslope winds will not be enough to dry out the
lowest levels completely. Thankfully, this band looks to be
short-lived even if the moderate bands of snow materialize. For
now, increased POP across the eastern plains and the I-25
corridor between 300 AM and 900 AM early Sunday morning for some
light to occasionally moderate snow. Conditions should improve
by noon Sunday outside of the mountains. Continued cold and
brisk with highs in the 30s to low 40s.
For Monday, models show moderating temperatures as a frontal
boundary lifts northeast as a warm front with highs returning to
the 40s to low 50s...and possibly mid to upper 50s for the
southern Nebraska panhandle. The third upper level shortwave and
associated jet max is forecast to push south and east across
Montana and the western Dakotas, much further north compared to
the ones this weekend. Other than lingering strong gusty winds,
expect snowfall to gradually taper off to flurries for the high
valleys and high plains. Snow showers will continue for the
mountains, but additional accumulations on Monday will be below
2 inches.
.LONG TERM...(Saturday through Thursday)
Issued at 243 PM MST Sat Dec 2 2023
The long term forecast continues to remain unsettled as we
anticipated strong winds, a temporary warm up, and then the chance
for rain and snow showers by next weekend. Near-record high
temperatures will be possible by mid-week for several areas as a
dominant upper level ridge amplifies across the region.
The period of strong winds across the wind prone corridors will
begin to wind down on Monday night across southeast Wyoming.
Northwest flow aloft at H5 and H3 will prevail, and there is a
chance of residual snow showers to occur, especially the Snowy and
Sierra Madre mountain ranges. The potential for light accumulations
in forecast zones 112/114 remains through Tuesday morning. The end
of the High Wind Warnings should wind down by daybreak, as elevated
wind gusts above 50mph will persist through midday Tuesday along the
spine of the Central Laramie Range. The remainder of the day will
see a transition, further upstream over the Great Basin, to upper
level ridging. The warming of the mid-levels will translate down
toward the surface via subsidence from a building dome of High
pressure. Tuesday will see afternoon highs west of the Laramie Range
in the 30s and 40s, and the mid to upper 50s for areas east of the
Laramie Range.
Wednesday will be the warmest day as the axis of the upper level
ridge bisects our cwa. Surface high pressure will be centered over
the triple point of southwest WY and northeast UT/northwest CO.
While this isn`t all that important normally, a swiftly moving
Alberta Clipper over the Northern Plains will eject toward the Great
Lakes by midday Wednesday. The surface pressure tendencies will
tighten, and gusty westerly winds will create a downslope effect for
the foothills east of the Laramie Range. Much above average
temperatures on the lee side of the Laramie Range mountains will be
present by the afternoon timeframe. Expect daytime high temperatures
to be in the upper 50s to middle 60s. A couple locations will
approach their daily record high temperature mark, so we will be
paying attention to that as well. By Wednesday night, model guidance
is depicting another strong signal for mountain wave activity to
begin taking shape across southeast WY. This favors another possible
High Wind headline issuance for the wind prone corridors.
Thursday through Saturday begins to have a myriad of model
differences regarding the potential for strong winds for a prolonged
period of time, and transitions into the next potential weather
system. The GFS has a progressive wave that sweeps through the
Intermountain West rather quickly, leaving a narrow window for
accumulating snowfall. However, the ECMWF and Canadian models have
a more impressive weather event advertised with moderate to heavy
snowfall accumulations by next weekend. As always, better
atmospheric sampling will occur this week to output a more confident
forecast as we approach the end of the week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon
through Sunday afternoon) Issued at 1030 MST Sat Dec 2 2023
SHSN will develop late tonight around KRWL and KLAR which could
impact visibility and also lower CIGs. Periods of MVFR conditions
will be possible at these terminals overnight and through Sunday
morning. Strong gusty winds with gusts over 50 kts are possible
tonight at southeast Wyoming terminals. Winds will continue to stay
strong through Sunday. Winds will also increase across western
Nebraska terminals early Sunday morning and continue through the
day. Gusts over 40 kts could be possible at these terminals.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 5 PM MST Monday for WYZ104-105-107-109-
118-119.
High Wind Warning until 2 AM MST Tuesday for WYZ106-110-
115>117.
Winter Weather Advisory until 11 PM MST Sunday for WYZ111-113.
Winter Storm Warning until 5 PM MST Monday for WYZ112-114.
NE...None.
&&
$$
SHORT TERM...TJT
LONG TERM...BW
AVIATION...SF
Area Forecast Discussion
National Weather Service Dodge City KS
511 PM CST Sat Dec 2 2023
...updated aviation section...
.KEY MESSAGES...
- Strong northwest winds will overspread southwest KS Sunday
afternoon in the wake of a cold front, sustained in the 30-40
mph range with gusts up to 50 mph.
- Warming trend this week from Monday through Thursday, with record
highs potentially in jeopardy on Thursday.
- Cooling trend will commence Friday-Saturday ahead of the next
upper level wave which could bring impactful weather next
weekend.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 200 PM CST Sat Dec 2 2023
Latest water vapor satellite imagery and RAP upper air analysis
indicates longwave troughing encompasses the entire CONUS, with a
pair of shortwave impulses over the Pacific Northwest and nearly
directly overhead the central plains. The latter feature was
responsible for the widespread stratus and drizzle this morning
and early afternoon across our area, but as the trough axis has
progressed eastward, the cloud deck has eroded from west to east,
with much of southwest KS now under clear skies. Given the
discrepancy in the amount of solar insolation based on residence
time of the stratus deck, afternoon highs will range from the
low/mid 50s across the western zones to the low 40s near central
KS.
Overnight tonight, clear skies and westerly winds around 8-12 mph
will support modest radiational cooling as the Pacific Northwest
upper level disturbance digs rapidly southeast, and Sunday
morning lows will dip into the 20s for most locations. As the
aforementioned upper level impulse approaches, a surface cyclone
will move from the northern plains southeastward into the Ozarks
region, dragging a cold front along with it that will pass through
southwest KS sometime during the late morning/early afternoon
Sunday. Strong northwesterly winds can be expected in its wake,
sustained in the 30-40 mph range with gusts up to 50 mph. Very
little cold air will reside behind this front, however, and
afternoon temperatures will still range from the low 50s north to
the upper 50s near the KS/OK border. As evening becomes night,
northwesterly winds will quickly decline with the loss of boundary
layer mixing down to 5-15 mph. This along with clear skies will
again allow modest radiational cooling overnight, with lows
dropping slightly cooler into the mid-teens northwest to mid 20s
southeast.
.LONG TERM...(Monday through Saturday)
Issued at 200 PM CST Sat Dec 2 2023
Medium range ensembles agree the upper level longwave trough axis
will have progressed east by the beginning of the long term
period, extending from the Great Lakes through the Midwest and
Dixie Alley and into the GoM as weak longwave ridging becomes
established across the far western CONUS. During the day Monday,
these upper level features will continue eastward as the ridge
builds, resulting in a much warmer afternoon on Monday with highs
in the low/mid 60s. Monday night, ensembles agree another upper
level vorticity max on the western periphery of the longwave
trough will dig southeast from the northern plains into the
Midwest, sending another cold front through southwest KS.
Northwest winds in the wake of this front will be considerably
weaker than Sunday`s, but will have enough cold air behind it to
halt the warming trend as afternoon highs on Tuesday will be
roughly comparable to Monday.
On Wednesday, ensembles agree the upper level ridge will move
overhead of the central plains as it dampens, and push the surface
high pressure center to near the ArkLaTex region. Anticyclonic
flow around this feature will support southwesterly, downsloping
winds across southwest KS, and combine with synoptic-scale
subsidence to revive the warming trend as afternoon highs increase
into the mid/upper 60s. By Thursday, ensembles agree the upper
level ridge will have completely flattened, resulting in zonal
flow across the central plains. Despite the loss of subsidence,
clear skies will allow sufficient solar insolation for
afternoon highs to increase a few degrees into the upper 60s/low
70s.
Friday through the end of the period, steadily decreasing 500-mb
heights ahead of the next strong upper level wave beginning to dig
southeast from the Pacific Northwest suggests a cooling trend
will commence across our area. And once this upper level feature
reaches the central Rockies sometime Friday night or early
Saturday, precipitation chances will increase over the central
plains. While EPS and GEFS probability of QPF exceeding 0.1" is
only in the 10-30% range, there is a reasonably strong signal in
the meteograms for precipitation next weekend, as roughly 70% of
EPS and GEFS members forecast at least some QPF. This wave could
certainly bring our next impactful winter weather storm, but a lot
can change between now and next weekend, so trends will be
monitored closely.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 506 PM CST Sat Dec 2 2023
Another cold front is forecast to drop south across the area by
18z Sunday. In the meantime, broken mid to high clouds cover the
area. Although low clouds in the IFR neighborhood of 1000 ft are
covering the southeast third of the area, they are trending away
from the local terminals with time and forecast to continue doing
so. The light northwest winds will back slightly southwest
overnight, before gaining northwesterly momentum again Sunday
morning with the passing to the aforementioned cold front.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 25 54 24 62 / 0 0 0 0
GCK 22 51 22 60 / 0 10 0 0
EHA 25 57 23 63 / 0 0 0 0
LBL 22 56 22 61 / 0 0 0 0
HYS 22 50 22 61 / 0 10 0 0
P28 27 57 27 60 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Springer
LONG TERM...Springer
AVIATION...99
Area Forecast Discussion
National Weather Service Gray ME
1042 PM EST Sat Dec 2 2023
.SYNOPSIS...
Low pressure approaches from the Ohio Valley late tonight and
Sunday bringing increasing chances for snow across the north and
rain south of the mountains. Low pressure forming near southern
New England will bring the potential for significant snowfall
across the foothills and points northward while there is
uncertainty in the rain/snow line across the south. There
remains potential for impacts into the Monday morning commute
due to wintry conditions. The system exits Monday afternoon with
snow showers lingering into Monday night. A drying trend
follows into mid week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1045 PM Update... Minor changes to reflect latest observational
trends. Areas of fog continue across the region with visibility
at times down to around 1/4 mile. These pockets of dense fog
have been rather sporadic though and in some cases visibility
has been improving as the clouds increase ahead of our storm
system. Will therefore hold off on issuing a dense fog advisory
for now but if traveling please still use caution and be
prepared for reduced visibility.
Previously...
700 PM Update... Nighttime microphysics satellite imagery shows
an advancing cirrus shield in association with approaching low
pressure to our southwest with some breaks in the cloud cover
beneath this. These breaks in the clouds combined with a
plethora of low-level moisture and light winds is allowing
fairly widespread fog to form across the region, with a few ASOS
visibility observations already down to around 1/2 mile. The
latest HREF indicates that similar to last night, patchy to
areas of dense fog are possible overnight and therefore will
continue to watch trends for the potential need of a dense fog
advisory. Otherwise, the inherited forecast remains largely
unchanged.
Previously...
A fairly calm night tonight with some patchy fog across the
mountains and interior. Winds should become more directional
from the northeast after midnight, and this will be critical for
bringing cool air in ahead of precipitation Sunday afternoon.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
A winter storm will impact the region Sunday into Monday
morning.
Low pressure passing up the eastern Great Lakes will combine
with return flow to bring moisture through the column into New
England. While QPF trends have lightened from yesterday, some
localized areas could see enhancement, namely the mountains and
potential areas of central Maine where banding could enhance
snow rates. Overrunning moisture may contribute to seeder/feeder
mechanisms allowing a bit earlier start time than prev forecast.
All snow is expected across the mountains and foothills where
snow will begin shortly after noontime Sunday. Here, a Winter
Storm Watch has been issued where snow amounts may total above 6
or 8 inches of snow. Notable snow rates may not enter the
region until mid afternoon Sunday as the low tracks through the
eastern Great Lakes. Further enhancement of rates is forecast
into the overnight and early Monday morning hour. HREF rates
show this most likely across portions of central ME;
Franklin/Somerset Co. These rates may approach 1" per hour
during the early Monday morning timeframe as low pressure
deepens and starts to transfer to the Gulf of Maine. Snow
consistency may be wet, allowing for weighing on tree branches
were snow accumulation continues. Combined with this, winds
across the ridges may gust up to 35 mph at times from the east.
For portions of central and western NH, valleys are expected to
warm enough to keep snow ratios low. This will affect
accumulation in the lowland, with higher elevations seeing more
accumulation. Thus travel here will be slick or treacherous at
times depending on elevation. Despite this, overall confidence
is below Warning level snows will impact the lower elevations,
and a Winter Weather Adv was instilled here. Extension of the
Advisory may be needed if snow prolongs into Monday.
The most uncertainty currently lies with a region over interior
Maine towards the ME capitol region. While model consensus
continues to bring warm surface temps here, cold air damming
ahead of the advancing low should lock in temperatures close to
freezing in this region. The NAM has been the most continuous
with this, but HRRR also resembles this pattern which enhances
confidence. Combined with increasing precipitation rates into
the overnight period, what falls may well be mostly snow in this
region. It has been noted that sometimes the HRRR can overdo the
NE cold advection in a dam situation, so did edit values a bit
warmer than HRRR brings. Regardless of outcome, Monday morning`s
commute would line up well with when a heavier band of
precipitation may be tracking through the region, leading to
snow being the likely precip type at the time. Thus preparations
for slick travel the morning of should be taken.
Mostly rain is expected along the immediate coast and outside of
higher terrain of southern NH. However, with cold air aloft,
can`t rule out snow mixing in for a decent portion of the event,
particularly towards the Midcoast of Maine. The problem for
snow accumulation comes with much lower ratios which will
inhibit good dendrite resilience at surface conditions.
Precip rates as well as accumulation potential will begin to
dwindle across southern and central NH and southern ME through
the early Mon morning hours. This comes as the DGZ begins to dry
and the result may be drizzle or just some flakes for the
morning commutes in southern NH.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Monday will feature a departing low pressure system, with the
steady snow ending during the morning hours in the mountains and
foothills. However, the low levels will remain moist as the mid
levels dry out, so we suspect there will be a decent amount of
drizzle around Monday, especially on the coastal plain.
The column moistens up again late Monday and Monday evening as
the main main short wave trough moves overhead. Enough forcing
for ascent looks to be present to allow for a period of snow
showers, with some accumulations possible especially in the
mountains and foothills.
The system departs later Monday night and Tuesday with drier
conditions expected. Another short wave trough, likely moisture
starved, looks to move through later Tuesday night Wednesday
with the potential for a few more snow showers.
The next chance of widespread but mainly light precipitation
looks to be Friday or Saturday.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
Short Term...LIFR, IFR, and MVFR are expected through Sunday
night. MVFR ceilings this evening will trend IFR tonight,
remaining down through the day Sunday and Sun night. RA will
onset during the late morning for terminals such as MHT, PSM,
CON. Further to the north, this will fall as RA/SN such as LEB
PWM, and RKD. Further yet, all SN will be possible for points
from HIE to AUG. SN would hinder vis down to a mile or less at
times through Sunday night. Heavier snow bands will be possible
from IZG to GNR late Sun night, with vis potentially down to
one half mile.
Long Term...Low cigs and periods of rain and snow likely bring
IFR conditions Monday into Monday night. Coastal and southern
terminals likely see mainly rain while the snow falls in the
interior. Conditions likely improve to mainly VFR Tuesday into
Wednesday.
&&
.MARINE...
Short Term...While low pressure will be passing through the
waters over the next 36 hours, little more than SCA conditions
are expected. These will primarily take place during the Sunday
afternoon through Monday morning timeframe. NE winds will gust
to 30 kt at times, with just a few hours of 25 kt possible for
bays/harbors.
Long Term...Winds and seas generally stay below SCA thresholds
Monday afternoon into Midweek but a few bouts of 25 kt gusts
and a few 5 footers can`t be ruled out during the period.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Watch from Sunday afternoon through Monday
morning for MEZ007>009-012>014-033.
Winter Storm Watch from Sunday evening through Monday morning
for MEZ020>022.
NH...Winter Storm Watch from Sunday afternoon through Monday
morning for NHZ001-002-004.
Winter Weather Advisory from 1 PM Sunday to 10 AM EST Monday
for NHZ003-005-006.
MARINE...Small Craft Advisory from 1 PM Sunday to 1 PM EST Monday for
ANZ150-152-154.
&&
$$
Update...Tubbs
NEAR/SHORT TERM...Cornwell
LONG TERM...Ekster
Area Forecast Discussion
National Weather Service Indianapolis IN
757 PM EST Sat Dec 2 2023
.Key Messages...
- Rain chances tonight and early Sunday
- Continued Cool.
- Additional rain chances again Monday and Tuesday
- Return to near normal temperatures next week
&&
.Forecast Update...
Issued at 756 PM EST Sat Dec 2 2023
An upper trough, seen in H20 imagery over the southern Plains, will
pivot northeast to the Ozarks overnight. Forcing associated with
this feature along with an associated surface system and a modest
approaching low level will bring showers to the Wabash Valley
shortly after Midnight. Despite that, Hi-Res soundings were showing
moisture contained to the surface to 8K feet which should keep QPF
on the low side. That said, still expecting 60% coverage over the
upper Wabash Valley with lesser coverage southeast. Radar mosaic and
obs were indicating the leading edge of the showers was currently
over the Ozarks. CAMs were having on good handle on that and support
showers moving into the Wabash Valley around or shortly after
Midnight.
With warm moist advection and cloudy skies, temperatures will not
fall much further than the upper 30s overnight.
&&
.Short Term...(This evening through Sunday)
Issued at 300 PM EST Sat Dec 2 2023
Surface analysis this afternoon shows low pressure over western NY
with a trough axis stretching SW across northern OH to Northern
Indiana and Central IL. High pressure was found across Quebec and
Ontario, spilling southwest into the western Great Lakes and the
northern Mississippi River Valley. GOES16 shows extensive cloud
cover across the region, with Mostly cloudy skies found across
Indiana and the Ohio Valley. Surface Winds were light to calm.
Aloft, water vapor showed a trough over the Rockies. Southwest flow
ahead of the trough was resulting in a plume of tropical air flowing
across eastern TX to Indiana and the Ohio Valley. Radar shows the
nearest precipitation upstream of Indiana over Central OK.
Tonight...
Models suggest tonight that the southwest flow aloft will persist
overnight. A short wave within this flow is expected to quickly
advance northeast toward Central Indiana late this evening and
during the overnight hours, providing moderate forcing across the
area. At the moment, showers with this short wave were found across
OK, progressing northeast. Models suggest this forcing arriving in
Indiana near 04-05Z. HRRR suggests scattered light rain
precipitation, with best organization across NW Central Indiana.
This is in the vicinity of the weak surface trough in place. Thus
will focus highest pops across the northeast and trend toward lesser
pops across the southeast. Much of the evening hours should remain
cloudy, dry and cool as we have seen in the past several hours.
Given the expected overnight clouds and rain, lows in the lower to
middle 40s will be expected.
Sunday...
We will start the day with the previously mentioned short wave over
Central Indiana. This wave will be producing continued moderate lift
within a nearly saturated column and continue to produce scattered
showers. Meanwhile surface low pressure will be moving north of
Indiana, and will drag a weak cold front across Indiana through the
course of the day. Again, best forcing and organization appears
across the northern parts of Central Indiana, but HRRR does suggest
the possibility of a thin band of showers ahead of that boundary. As
forecast soundings show a nearly saturated column and the tropical
flow still in play aloft. Pops will need to be continued through at
least the morning hours.
By afternoon, the best forcing along with the low to the north will
have departed and winds are expected to become westerly along with
the onset of cold air advection. Thus highs will once again remain
rather cool, reaching only the mid to upper 40s.
&&
.Long Term...(Sunday night through Saturday)
Issued at 300 PM EST Sat Dec 2 2023
The fist half of the long term period will bring up to a 40% chance
of rain as multiple quick succession short waves pass through the
area. These waves will not have much moisture to work so expecting
light precipitation. Monday`s wave will see best chances for light
rain across the southern portion of the forecast area while
Tuesday`s will see best chances across the north and west.
Temperatures through midweek will see highs in the 40s and lows in
the low 30s. Some light snow or a rain/snow mix could occur at times
as temperatures approach freezing.
Ridging will then settle into the region as it progresses eastward.
This will cause high temperatures to warm into the 50s and low 60s
for the rest of the work week as well dry weather. Models are each
showing another trough moving in that could bring precipitation next
weekend as well. For now, models vary too much in timing and depth
so details are unclear at this time.
&&
.Aviation...(00Z TAF Issuance)
Issued at 540 PM EST Sat Dec 2 2023
Impacts:
- Mainly MVFR flying conditions are expected with improvement
likely after 21z Sunday
- Showers possible at KLAF and KHUF as early as 06z and KIND and
KBMG around 08z
- Wind gusts to near 25 knots from the southwest Sunday afternoon
Discussion:
A warm front will lift north across the terminals overnight and a
cold front will follow and move east across the terminals Sunday
morning. Moisture will be increasing in advance of these features
and the combo will bring showers across the terminals overnight and
Sunday. The showers will then move to the east early Sunday
afternoon.
Flying conditions will mostly be MVFR until late Sunday, when
improvement is likely. IFR conditions will also be possible with the
showers, especially at KLAF, where the best chance of showers will
be.
Winds will be very light to calm tonight and become southwest and
west Sunday with wind speeds around 15 knots and gusts to near 25
knots Sunday afternoon.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...MK
Short Term...Puma
Long Term...KF
Aviation...MK