Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/16/18
Area Forecast Discussion
National Weather Service Albany NY
949 PM EST Thu Nov 15 2018
A coastal low pressure system will spread accumulating snow
into the region from south to north this evening into tonight.
The snow will be heavy at times. The snow is expected to mix
with sleet and freezing rain for areas from around Albany south
and east. Wintry precipitation tapers off from west to east
Friday late morning into early afternoon, with additional lake
effect snow possible for the higher terrain. Continued colder
than normal temperatures expected for the weekend with mainly
dry conditions outside of the lake effect belts.
.NEAR TERM /THROUGH FRIDAY/...
...A Winter Storm Warning remains effect until 1PM Friday for
the Capital District, Schoharie Valley, Mohawk Valley, Lake
George Saratoga Region, northern Taconics, and Helderbergs of
eastern New York, the Berkshires of western Massachusetts,
Litchfield County of Connecticut, Windham County in Vermont, and
the southern Adirondacks...
...Winter Weather Advisory remains in effect until 1PM Friday
for the Mid Hudson Valley, northern Taconics, Washington County
of New York and Bennington County of Vermont...
As of 945 PM EST, very heavy snowband earlier this evening
pummeled the mid Hudson Valley, Litchfield County CT, and the SE
Catskills with a very quick 6-10 inches of snow (if not locally
higher). Strong mid level frontogenetical forcing and isentropic
lift at the nose of a east/southeast low level jet likely
contributed to the intensity of this band. However, as it
slowly tracked north, overall intensity weakened. Latest IR
satellite imagery reveals coldest cloud tops of shifted north
and east of the region, with decreasing ice nuclei in the
clouds, and reducing the snow accumulation efficiency compared
to earlier when aggregates of dendrites (more like clumps of
dendrites!) were falling. Still moderate to locally heavy snow
occurring across the western/central Mohawk Valley and tracking
into the SW Adirondacks and Saratoga/Lake George region over the
next few hours, where a quick 2-5 inches may occur by midnight,
otherwise expecting decreasing intensity of snow, with some
sleet mixing in from the I-90/I88 corridor south and east.
Expect mainly sleet/freezing rain across the I-84 corridor and
Litchfield County over the next few hours, although still could
be some bursts of snow mixed in through midnight.
Have increased snowfall amounts in southern areas into the 8-12
inch range, most of which has already occurred. Elsewhere, still
expect a general 6-10 inches in the warning areas, with locally
higher amts possible across the eastern Catskills and especially
SW Adirondacks. Still expect sub-warning snow amounts across the
northern Taconics and lower elevations of Bennington County,
with generally 3-5 inches expected overnight, and perhaps an
additional 1-2 inches around or shortly after daybreak Friday.
Evap cooling has allowed temps to drop into the lower/mid 20s in
many areas, and only expect a slow climb in temps toward
Previous discussion follows...
Our winter storm is on track to bring the first widespread
snowfall to all of eastern New York and western New England
starting this evening and continuing into Friday morning. The
coastal low as of 4PM EST is near Cape Hatteras, NC with a MSLP
of around 1005mb based on the latest RAP analysis. Latest GOES16
water vapor channels show the parent potent cut off shortwave
still holding strong over the TN Valley providing very strong
upper level divergence which will enable our coastal low to
intensify further over the coming hours. We also can see a
pronounced baroclinic leaf on water vapor channels over
spreading into the Northeast associated with the approaching
laterally transient snow band as has been researched in previous
Latest observations show dew points in the single digits to low
teens over the Albany forecast area with the band of heavy snow
moving north of the NYC metro area. However, the dry air is no match
for the impressive isentropic lift and intense 700-500mb
frontogenesis associated with this band and we have seen most of the
airports saturate quickly and report snow once radar
reflectivities encroach into the region. In fact, both JFK and
EWR have reported 2 inch per hour rates within this band and
such intensities are expected to occur in the mid-Hudson Valley
and Litchfield, CT this evening. Given temperatures in the upper
20s, snow should have no issues accumulating on any untreated
surface which could lead to a dangerous evening commute. This
was one of the reasons we issued a winter storm warning for
these areas. We have been issuing Special Weather Statements to
reflect the dangerous travel conditions under this band.
The band should continue tracking northward this evening, reaching
the Capital District around 7-9pm with high snowfall rates still
possible as BUFKIT profiles show strong omega through a deep layer
in the column and even intercepting the dendritic snow growth zone
which is situated rather high in the column between 600-500mb. The
laterally transient snow band should bring a 4-5 hour window of high
impacts to eastern New York/western New England including snowfall
rates of 1 inch + per hour before the strong 45-50knot mid-level jet
pushes the band into the Upper Hudson Valley and the Adirondacks by
10pm-1am tonight. During this period, the majority of the storm
total snowfall is expected to accumulate. Despite the cold surface
temperatures, snow ratios may actually not stray much from
climatology, peaking only near 10-12:1 during this period due to an
upper level warm nose and we even expect snow ratio to drop near or
under 10:1 as the band moves out of the region. The SE wind regime
means downsloping effects could limit snow accumulations for
Washington County, the northern Taconics as well as the valley of
Bennington County, VT so decreased snow totals there and continued
with only a winter weather advisory.
Once the bands reaches the Adirondacks/Upper Hudson Valley, we are
expecting the laterally transient band to stall for a few hours as
the parent shortwave opens up and our coastal low becomes the
dominant feature off the coast of NJ/Long Island. The band could
become a pivoting band near the foothills of the Adirondacks down
into the Mohawk Valley as shown in the latest hi-res and HREf
guidance. Areas south will likely enter into the warm/dry sector
after Midnight with heavy snow transitioning to scattered sleet and
freezing rain/drizzle. Surface temperatures likely remain near or
below freezing all night so ice accretion is possible, especially in
the Litchfield County, Berkshires, Taconics, eastern Catskills,
Schoharie and mid-Hudson Valley. Up to 0.10 of inch of ice is
possible in the higher elevations. Some uncertainty still remains
with how far north the warm/dry sector extends but the latest
forecast soundings show a weak warm nose signature up to ALB so
mixed sleet up into the Capital District.
Heading into Friday morning, the pivoting band should finally push
eastward from the foothills of the Adirondacks/Mohawk Valley towards
the Capital District and areas east as our coastal low starts
exiting out to sea. This means areas previously in the warm/dry
sector could see moderate snow return for a brief period with an
additional 1-2 inches possible. This would impact the Friday morning
commute time. However, the band should exit into New England by late
morning/early afternoon Friday as our coastal low exits into the
Gulf of Maine. Storm total snowfall amounts are expected to range 5
to 10 inches across eastern NY and western New England with the
highest amounts expected north and west of the Capital District
where less mixing is anticipated.
Once the snow exits, temperatures should finally warm into the mid -
upper 30s for Friday afternoon with breezy winds possible in the
wake of the departing coastal low. A weakening clipper from the
Great Lakes looks to lead to lake effect and upslope snow for the
afternoon hours for the Adirondacks and western Mohawk Valley.
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
The storm system will be well north and east of the region by
Friday evening, as the cyclone center will be moving through the
Canadian Maritimes. However, and additional short wave trough
aloft will be moving through our region during the evening,
which will enhance the snowfall potential with some upslope and
lake enhancement across the western Adirondacks. A period of
persistent snow showers through Friday evening will result in a
quick 1-3" of snow across mainly northern/central Herkimer and
western Hamilton counties. Outside of this area, mainly a
dusting to a few tenths of an inch will be possible in the
Mohawk/Schoharie Valley and southern Green Mountains. It will be
breezy through Friday night, with some upslope/lake enhanced
snow showers persisting in the western Adirondacks, although
inversion heights will be lowering as the short wave moves east
so lighter accumulations are expected after midnight.
On Saturday, with well-aligned westerly flow and conditional
lake induced instability, there will be at least scattered lake
effect snow showers across the western Adirondacks. Again, with
low inversion heights around 800 mb, and accumulations will be
very light. Elsewhere it will be dry with seasonable
temperatures. Went a little below MAV/MET guidance for max temps
Saturday due to expected lingering snow cover across much of
Late Saturday into Saturday night, a cold front will be pushing
southward across the area. This system looks to have limited
moisture and weak dynamics aloft, so the main driver for snow
showers will be convergence along the boundary, picking up some
lake moisture due to continued westerly flow aloft. Again, we
are expecting only a dusting to a half inch in some spots,
mainly of areas west of the Hudson Valley. By late Saturday
night, temps will plunge back into the teens and 20s in wake of
the cold front.
Sunday will be mainly dry and cold, with surface high pressure
in place. Max temps will likely be around 10 degrees below
normal. Some snow showers will be possible later in the day, as
a weak short wave trough approaches from the west. Will only
mention 20-30 pops at this time, as there is some disagreement
among sources of guidance. QPF looks to be light though through
the daylight hours with only a dusting of accumulation possible.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The period begins with widespread snow that quickly pulls off
the New England coast. A cold front keeps snow showers in the
area of the northern Adirondacks through Tuesday night. The
balance of the period will be dry as high pressure gradually
builds in from the southeast.
Temperatures will be colder than normal, with highs ranging
from the mid 20s to upper 30s on Monday, around 20 degrees to
the mid 20s on Tuesday, and rebounding back to the mid 20s to
upper 30s on Thanksgiving. Lows Sunday night will range from the
upper teens to near freezing Sunday night, from around 10
degrees to the mid 20s Monday night, and the mid single digits
to lower 20s Tuesday night. Readings will begin to moderate
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Low pressure will track rapidly northward along the mid Atlantic
coast overnight, and off the New England coast during Friday.
Moderate to heavy snow will overspread the TAF sites from south
to north this evening, with conditions rapidly dropping to IFR/LIFR
within about an hour of snow onset. Heavier snowband at KPOU
will track northward reaching KPSF within the hour, and KALB
between 01-02Z/Fri, and KGFL closer to or after 03Z/Fri. The
heaviest snow should last 1-2 hours in duration.
After a few hours of this, intensity will lower and some mixing
with PL/FZRA will occur at KPSF/KPOU. Some sleet is also
possible at KALB, and may mix with sleet eventually at KGFL.
Visibility will improve somewhat for the 2nd half of the
overnight hours, but ceilings will remain borderline for
IFR/MVFR through the rest of the overnight.
Towards daybreak, another round of steady precip (mainly in the
form of snow) is expected for a few hours into Friday morning.
Visibility/ceilings will likely be IFR with this precip. Snow
will taper off by 15-17z, allowing for visibility to improve,
although some lingering MVFR ceilings are possible, especially
Winds will become north to northeast and increase to 8-12 KT
this evening, then back into the north to northwest at similar
speeds Friday. Some gusts of up to 20-25 KT will be possible,
esp at KPSF.
Low level wind shear is likely overnight, as surface winds
remain N to NE at 8-12 KT while winds around 2000 FT AGL become
east to southeast and increase to 30-40 KT.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: Low Operational Impact. Slight Chance of SHSN.
Sunday: Low Operational Impact. Slight Chance of SHSN.
Sunday Night: Moderate Operational Impact. Chance of SN.
Monday: Moderate Operational Impact. Chance of SHRA...SHSN.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: Low Operational Impact. Slight Chance of SHSN.
Widespread wintry precipitation expected this evening into
Friday. Then, it will be mainly dry outside of lake effect and
upslope areas, but continued unseasonably cool through the
A strengthening coastal low pressure system will bring
widespread wintry precipitation to the region from this evening
into Friday. The precipitation is expected to change to sleet
and/or freezing rain especially from the Capital District south
and east tonight into early Friday morning. QPF ranges from
around 0.50 to 1.25 inches, with the heaviest amounts over the
Mid Hudson Valley, Litchfield County, and the Berkshires where
rivers are already running high. Flooding on the main stem
rivers is not expected, but some urban and poor drainage
flooding cannot be ruled out due to the saturated ground as
tempertures rise above freezing on Friday.
It will be mainly dry for the weekend outside of lake effect
snow over the western Adirondacks.
CT...Winter Storm Warning until 1 PM EST Friday for CTZ001-013.
NY...Winter Storm Warning until 1 PM EST Friday for NYZ032-033-
Winter Weather Advisory until 1 PM EST Friday for NYZ043-054-
MA...Winter Storm Warning until 1 PM EST Friday for MAZ001-025.
VT...Winter Storm Warning until 1 PM EST Friday for VTZ014-015.
Winter Weather Advisory until 1 PM EST Friday for VTZ013.
Area Forecast Discussion
National Weather Service Bismarck ND
1001 PM CST Thu Nov 15 2018
Issued at 935 PM CST Thu Nov 15 2018
No significant updates to the going forecast. Updated hourly
temperatures through 12 UTC, and this raised mins a bit. But the
cloud free southwest had already dropped to near fcst lows. This
won`t last long though as clouds will be on the increase shortly.
UPDATE Issued at 544 PM CST Thu Nov 15 2018
Light snow is exiting the far southeast portion of the forecast
area early this evening. Otherwise Breezy but diminishing winds
this evening with mostly cloudy skies. The far southwest may
escape the cloud cover during the early evening, but mid and high
clouds will approach from the west with the next system. Only some
minor tweaks this evening. We did hold off on precip entering the
far west until after 06 UTC. No changes to the current hazards.
Updated products out shortly.
Looking ahead to Friday, see no reason to adjust current hazards
at this time. Both the NAM and GFS just coming in with latest 00
UTC iterations and both seem very consistent from their previous
run regarding the track. GFS still a bit farther southwest than
the NAM. Both are slightly higher in overall qpf. Looking at cross
sections of the 18z run, both indicated a band of strong omega
throughout the dendritic growth zone tracking along and near Lake
Sakakawea and the Missouri River, and into the southern James
River Valley. Within this area there are periods of negative EPV
signifying the potential for heavier bands of snow, within the
advisory area. Exactly where these set up will be hard to
determine until the event gets underway.
One other point to mention. After coordination with ABR...will
pass on to the mid shift, the potential for stronger winds than we
are currently carrying. There is a very strong isallobaric fall
rise couplet that tracks across the southwest and south central,
in concert with strong cold advection and decent lapse rates. The
strongest winds would likely be over the southwest, where lesser
snow amounts are forecast, but we can`t rule out some strong winds
over the west central into the south central with falling snow and
continuing after the snow ends.
.SHORT TERM...(This evening through Friday Night)
Issued at 303 PM CST Thu Nov 15 2018
Accumulating snowfall late tonight through Friday highlights the
short term forecast.
The 12-18 UTC global and high resolution suites have trended
slightly higher with QPF and a bit further north with the axis of
the greatest snowfall for late tonight through Friday. As with
any banded snow event, some uncertainty remains and a slight shift
in the snowfall axis is certainly possible as low pressure
propagates southeast along the baroclinic zone of the leading
edge of the cold high pressure system. A zone of strong
frontogenesis is expected to couple with deep layer forcing with
moderate mid level lapse rates to generate a band of moderate, to
at times heavy, snow from northwest and north central through
south central North Dakota and the James River Valley. Widespread
snowfall amounts of 3-6 inches are forecast for these areas.
Isolated higher amounts are possible, but their placement is
highly uncertain and dependent on any shifts in the band. Issued a
Winter Weather Advisory for the northwest and north central
through the south central and most of the James River Valley
beginning first across the northwest late tonight, and spreading
southeast Friday morning. Blowing snow is possible Friday
afternoon as gradient winds and cold air advection increase.
However, the strongest isallobaric forcing does not couple well
with the gradient winds, limiting how significant blowing snow may
become. A northwest to southeast oriented snow band with a
similarly tracking low suggests the snowfall residence time will
be long, despite the fast moving nature of the system. Again,
while confidence for higher snowfall amounts has increased to
warrant a Winter Weather Advisory, the banded nature of the event
supports some continued placement uncertainty. If a shift in the
guidance occurs, it would most likely be a northward shift as
depicted by the 18 UTC HRRR and RAP. Isolated amounts in excess of
6 inches are also not out of the question.
.LONG TERM...(Saturday through Thursday)
Issued at 303 PM CST Thu Nov 15 2018
A cold Saturday with a slow moderating trend in temperatures next
week highlights the extended forecast.
A cold Saturday is favored by the 12 UTC global suite with cold
high pressure in place. High temperatures will range from 15 to 20
for most areas. Thereafter, cyclonic flow aloft is expected to
transition to mean ridging by mid next week, favoring a slow
moderation in temperatures to near to slightly above normal.
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 935 PM CST Thu Nov 15 2018
Widespread MVFR cloudiness across wester and central ND to begin
the 00Z TAF period. Areas IFR around KJMS early this evening.
KDIK and KISN are right along the western periphery of clouds
tonight and may break out to VFR conditions during the evening
Late tonight a system will approach from the west bringing
widespread MVFR-IFR ceilings and visibilities in snow to all TAF
sites. Snow will begin in KISN and KDIK before 12 UTC and spread
east through the morning hours. Periods of LIFR cigs and vsbys
expected during the heaviest snow. Northerly winds pick up in the
afternoon, keeping MVFR visibilities in blowing snow at TAF sites
even after the snow ends.
Winter Weather Advisory from 3 AM CST /2 AM MST/ to 3 PM CST /2
PM MST/ Friday for NDZ001-002-009-010-017.
Winter Weather Advisory from 6 AM CST /5 AM MST/ to 6 PM CST /5
PM MST/ Friday for NDZ003-011-012-018>023-034>037-046>048-050-
Area Forecast Discussion
National Weather Service Burlington VT
944 PM EST Thu Nov 15 2018
A winter storm will bring widespread moderate to heavy snow to
the North Country from tonight through early Friday afternoon.
Expected snow totals will range from 5 to 10 inches through mid
day on Friday with another round of light snow Friday night and
Saturday. Quiet weather returns on Sunday.
.NEAR TERM /UNTIL 10 AM FRIDAY MORNING/...
As of 935 PM EST Thursday...Snowfall has entered southern
Vermont with areas as far north as Rutland now reporting snow.
Looking upstream across southern New England, snowfall rates of
2 to 3 inches per hour have been observed with a strong band of
700 mb frontogenesis. The big question will be whether this band
fizzles out over the next several hours or whether this band
continues to hold together as it moves through Vermont. Earlier,
high-res guidance was showing this feature fracturing and
weakening but the 00Z NAM and latest RUC and HRRR now all show
this band holding together across Vermont. Now, there are a lot
of factors to consider including an approaching dry slot which
is expected to push east of us while we wrap around Atlantic
moisture into the region. The overall forecast was bumped up
about a half inch to an inch across much of Vermont based on
where the models are currently placing this band while New York
remains rather untouched; especially over the Saint Lawrence
Valley. We will need to watch for the potential for higher
localized snow accumulations above our forecast values. Stay
tuned for further developments.
Previous Discussion...Low pressure forming off the coast
of North Carolina will phase with low over southern Indiana
overnight then lift along the east coast and be centered near
NYC Friday morning. Widespread snow will lift into our region
after about 8pm. Front edge of the snow is currently in a line
from Rochester to Binghamton to Poughkeepsie. Snow spreads north
across our area and will be heaviest between 1 - 7 am. This
will make the Friday morning commute very messy. At times we may
have 1-2 inch per hour snowfall rates as a mesoband lifts
across the area. Snow ratios will range from about 9-12:1
initially in the warm air advection burst of snow and then will
switch to 13-15:1 once low pulls to the northeast Friday morning
into the afternoon hours. Low will continue to lift
northeastward towards Nova Scotia by about 00z Saturday. As the
low lifts away, synoptic snowfall comes to an end during Friday
afternoon. Snowfall totals from the storm will range from 5 to
10 inches, lowest in the Saint Lawrence Valley and Western
Rutland Counties. Some areas will see upwards of a foot of snow,
especially in the higher elevations and wherever the mesoband
sets up. This will likely lead to some isolated power outages
and will certainly make travel difficult especially during the
Friday morning commute. The highest qpf totals fall from around
6-12z where region wide we`ll be looking at between 0.25-0.5" of
liquid equivalent. At this time most models indicating that dry
slot and warm nose should remain to our south and east. If the
dry slot does make it into our area, could have some lower
amounts especially in Southern Vermont. As the low pulls off to
our northeast we will have some wrap around snow showers
beginning during Friday evening. There won`t be a real clean
break between the snow from the low pressure system, then the
snow from upper level energy moving across the area.
.SHORT TERM /10 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
As of 400 PM EST Thursday...Flow aloft will be westerly Friday
night with a shortwave trough moving across southern Quebec and
northern New England. This will allow for additional light
precipitation but upslope flow will enhance precipitation across
northern New York and the northern half of Vermont. Eventually
the upslope flow will relax after midnight Friday night and the
areal coverage of the precipitation should decrease. Mountains
will pick up another couple of inches as a result of the upslope
flow. Plenty of cloud cover will persist Friday night for lows
only falling into the mid 20s to lower 30s.
Westerly flow continues on Saturday for highs in the 30s to
around 40 with a chance for some showers...especially in the
mountains. Secondary arctic front will push across the area
Saturday evening and with steep low level lapse rates could see
some snow squall activity. High pressure builds in Saturday
night for drier weather as precipitation comes to an end. Colder
air moves in with lows in the mid teens to lower 20s.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 356 PM EST Thursday...Still looking at a relatively
unsettled extended period but no major systems expected and
below normal temperatures through the entire period. High
temperatures will generally be in the low to mid 30s with lows
in the low teens to around 20...certainly continuing the cold
trend of this November. Ridging out west will keep much of the
US poised under a broad upper level trough with continued
unsettled weather through next week.
Surface high pressure builds in on Sunday, but upper level
troughing and NW winds will keep passing clouds around,
especially across the high terrain of the Adirondacks. Snow
showers may be possible across the high peaks, but expect
accumulations to be limited and confined to these areas.
Moisture increases Monday as two pieces of energy pass by the
area. Best chances for precipitation will be showers across the
northern tier and southern areas, with central Vermont in the in
between zones. Behind this front, cold air from Canada brings
another push of well below average temperatures. Conditions look
to be similar to what we`ve been experience these past two days
with high temperatures in the teens and 20s and lows in the
single digits to low teens. Moderating (but still below normal)
temperatures and quiet weather continues to be the early trends
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...Expecting VFR conditions to persist at
all TAF sites through 03Z under departing high pressure. After
03Z, snow will begin over Rutland, spreading northward and
affecting all TAF sites by 06Z. Once snow arrives, expecting
primarily IFR with some localized LIFR conditions through the
remainder of the period. Expect the heaviest/steadiest snow
between 06Z and 12Z, but scattered snow showers will continue
through the day Friday. There is the potential for some of the
snow to mix with rain between 18Z and 00Z at KRUT. Elsewhere,
precipitation will be all snow through the TAF period. Winds
will generally be 10 knots of less through the period.
Friday Night: Mainly VFR, with areas MVFR possible. Chance SHSN.
Saturday: Mainly VFR, with areas MVFR possible. Chance SHSN,
Saturday Night: MVFR. Chance SHSN.
Sunday: VFR. NO SIG WX.
Sunday Night: Mainly VFR, with local MVFR possible. Chance SHSN.
Monday: Mainly VFR, with local MVFR possible. Chance SHSN.
Monday Night: VFR. Chance SHSN.
Tuesday: Mainly VFR, with areas MVFR possible. Chance SHSN.
VT...Winter Storm Warning until 3 PM EST Friday for VTZ001>010-012-
Winter Weather Advisory until 3 PM EST Friday for VTZ011.
NY...Winter Storm Warning until 3 PM EST Friday for NYZ028>031-034-
Winter Weather Advisory until 3 PM EST Friday for NYZ026-027-
Area Forecast Discussion
National Weather Service Caribou ME
725 PM EST Thu Nov 15 2018
Low pressure will approach from the southwest tonight, track
across the Gulf of Maine Friday afternoon, then across Nova
Scotia Friday night. A cold front will cross Saturday night and
bring more Arctic air for Sunday and early next week.
.NEAR TERM /THROUGH FRIDAY/...
720 PM Update...Clouds continue to spread northward w/most of
this being high level based based on the IR satl imagery and obs.
Tweaked the sky conditions to match up w/the latest satl imagery.
Radar loop showed leading edge of returns moving into southern
New England. Hrly temps were adjusted to fit the current
conditions. Clouds will put a lid on a substantial drop in the
overnight mins. 00Z sfc analysis showed high pres centered over
eastern Maine and is expected to slide off to the east tonight.
Clouds will thicken up and lower as the evening progresses
w/precip moving into southern areas near or after midnight. The
latest run of the RAP initialized well w/its temps and precip
placement and will use this guidance for the next update.
Models are in a little better agreement with the track of the
sfc low xpctd to apch from the mid Atlc states coast by Fri
morn, with greater number of solutions favoring the more
progressive srn track toward the S Nova Scotia coast by Fri eve.
With this in mind, we believe the greatest potential will be
ovr N and E Cntrl ptns of the FA. Far Nrn ptns of the our FA
will experience a later start in snfl (mid to late Fri morn)
compared to the rest of the Rgn, with snfl here in the steady
lgt intensity, with perhaps some trowal-dendritic sn banding
setting up ovr this ptn of the FA by erly eve.
Downeast areas will see a late ngt inset of sn, with sn likely
mixing with or chgng to sleet and rn alg the immediate coast by
mid to late Fri morn, contg mixed til mid Fri aftn, before
briefly chgng back to sn late in the aftn prior to ending erly
Fri eve. A narrow belt of msly sleet will likely affect ptns
of the Lower Penobscot and interior Downeast from late morn to
erly aftn, lowering total snfl here somewhat, but not as much
reduction as the coast. In generating the hrly fcst wx types, we
employed the top-down method using the NAM, but kept the
transition zones closer to the coast in deference to colder
models tracking the low further S. It should be noted that not
much in fzra was indicated with this event, which was supported
by the SREF precip probs, which supported sn and sleet ovr the
Srn third of our FA ovr fzra with this event.
With all said and done in generating the snfl stm totals
including the myriad of precip types ovr the Srn third of the
FA where the greatest stm total QPF is xpctd was to go with
wntr stm wrngs for zones 15, 31, and 10 msly for public impact,
particularly zone 15 (lower penobscot vly) where totals are
slightly below wntr stm thresholds. Elsewhere we went with wntr
wx advs where either precip type or stm total QPF was still
uncertain, with the GFS dtmnstc and ensm solutions a concern
with relatively lighter amts.
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
Most places will be done with snow Friday evening. However, a
weak trough of warm air aloft over Northeast Maine will keep
snow going the longest there with another inch or two Friday
evening before finally ending.
Not much wind (10-15 mph) behind the system so not expecting
much blowing snow Friday night and Saturday...just a bit in localized
open areas. Actually somewhat mild on Saturday (the warmest day
of the week), with highs in the low 30s north and low 40s
Weak system moving through Saturday night with a few snow
showers mainly over the north and limited if any accumulation.
About 10 degrees colder Sunday behind the weak system.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Unseasonably cold weather persisting. Models having a lot of
issues with timing of systems in the extended. However, don`t
expect any of the systems to be strong. Also, high confidence in
cold to very cold temperatures. Best chance of a weak system is
Monday, but even then, just went with 40 to 60 PoPs.
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: VFR conditions this evening will progressively lower
to IFR beginning late tonight over Downeast TAF sites working
NE toward far Nrn ME sites by mid to late morn. All TAF sites
will cont IFR in sn Nrn sites and mixed precip Downeast Fri
SHORT TERM: Improving to VFR Friday night as the snow ends.
Generally VFR Saturday to Sunday, although a weak system
Saturday night could bring some MVFR ceilings mainly to the
north. Potential for a weak system Monday which could bring some
NEAR TERM: Will cont with the current gale wrng, with winds and
seas xpctd to ramp up quickly durg the ovrngt hrs as the pres
grad ahead of the coastal low apchs. E Winds will reach a max
durg the morn and midday hrs, then begin to slowly decrease durg
the aftn, dropping below gale criteria late in the aftn behind
the low as the direction becomes NW. Went with a NWPS/WW3
guidance blend for fcst wv hts.
SHORT TERM: Small craft Friday night and Saturday, but with a
gradual subsiding in winds and seas. Below small craft Saturday
night through Sunday night. Potential weak system Monday which
could bring a return to small craft.
ME...Winter Weather Advisory from 8 AM Friday to 2 AM EST Saturday
Winter Weather Advisory from 5 AM to 11 PM EST Friday for
Winter Weather Advisory from 3 AM to 8 PM EST Friday for
Winter Storm Warning from 2 AM to 8 PM EST Friday for MEZ010-
MARINE...Gale Warning from 3 AM to 4 PM EST Friday for ANZ050>052.
Area Forecast Discussion
National Weather Service San Francisco Bay Area
331 PM PST Thu Nov 15 2018
.SYNOPSIS...Smoke and haze will continue to produce poor air
quality over much of the San Francisco Bay through the weekend.
Dry and mild conditions are also likely to persist through early
next week. A more significant pattern change appears likely
during the latter half of next week with the potential for
.DISCUSSION...as of 1:58 PM PST Thursday...Smoke from the Camp
Fire continues to be the main impact across the district, but
especially around the greater San Francisco Bay Area where
visibilities continue to fluctuate between 1 mile and 3 miles.
These conditions are resulting in poor air quality with no
significant improvement forecast through the weekend as a weak
windflow pattern persists.
Minor day-to-day changes are expected through the upcoming
weekend with daytime temperatures in the 60s and 70s with
overnight lows in the middle 30s across the colder inland
locations to middle 40s near the coast/bays. Very dry conditions
will also persist, even near the coast through the weekend. Weak
offshore flow will continue to spread smoke over the region until
the large scale pattern aloft changes. Right now, this much-
needed pattern change isn`t expected to occur until the middle of
next week, at the earliest. Latest runs of the medium range models
continue to indicate a more likely chance of measurable rain for
the area. The 12z ECMWF maintains its trend of bringing a weak
frontal system across much of the area on Wednesday, followed by
a stronger front on Friday, with residual showers extending into
Saturday. The 12Z GFS holds off the first system until
Thanksgiving, followed by another system on Friday. The rainfall,
along with stronger onshore flow, is expected to help clear out
the smoke from the area.
.AVIATION...As of 03:31 PM PST Thursday...For 00Z TAFs. Widespread
smoke continues to impact the region, particularly around the SF
Bay area terminals. Most sites are now at MVFR/IFR conditions due
to reduced vis. Do not expect much if any improvement in smoke
through the period. MVFR/IFR vis will continue through the period
with occasional MVFR cigs. Slant range vis issues will also
persist and impact arrivals. Smoke impacts may remain an issue
until the next storm system, which right now looks like late next
week. Generally light winds through the period.
Vicinity of KSFO...MVFR/IFR vis with MVFR cigs due to wildfire
smoke. Winds will remain light.
SFO Bridge Approach...Similar to terminal.
Monterey Bay Terminals...Conditions have worsened to MVFR with
KMRY currently at 4 mile vis. Latest HRRR smoke forecast does not
suggest much improvement. Expect MVFR vis through much of the
period with occasions of VFR. Onshore winds will continue into
the early evening before turning southerly.
.MARINE...as of 03:01 PM PST Thursday...North to northwest winds
will prevail over the coastal waters through the end of the week
and into the coming weekend. Expect locally breezy winds near
coastal gaps and favored coastal jet locations during the
afternoon and evening hours. Mixed swell with a moderate northwest
swell and light southerly swell.
PUBLIC FORECAST: Sims
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Area Forecast Discussion
National Weather Service Blacksburg VA
807 PM EST Thu Nov 15 2018
An upper level low pressure area will bring about a changeover
from rain this evening to mountain snow showers. Limited snow
accumulations are expected from this short-lived period of snow
showers. Blustery and cold conditions are expected on Friday,
followed by fair but chilly weather for the weekend.
.NEAR TERM /THROUGH FRIDAY/...
As of 746 PM EST Thursday...Made several changes to headlines
with this update.
I`ve hoisted a heavily impacts-driven Wind Advisory until 9 AM
Friday from the foothills of the VA Blue Ridge, the mountains of
northwestern NC westward to southeastern West Virginia. Many
trees and powerlines in the Advisory have some glaze from
overnight and this morning`s freezing rain/sleet event, which
haven`t really melted significantly as temperatures have barely
reached freezing. 18z model guidance has trended stronger
regarding the potential for at least gusty NW winds behind
passage of a strong cold front later this evening, with 850 mb
winds of 40-45 kts and 6 hourly pressure rises near 5-6 mb.
Admittedly forecast wind gusts are quite marginal - between
40-45 mph with as much as 50 mph possible, but given the
weighed-down and glazed- up state of the trees and powerlines,
think some consideration has to be given to the potential for
these to be downed from these wind gusts. Excluded Smyth and
Tazewell Counties from this Advisory as temperatures in the
mid/upper 30s may allow for greater ice melt. Expired the Winter
Weather headlines, as most areas have transitioned to drizzle
and mist under the dryslot.
Upper-level low and lower-level cold front is now progressing
across eastern KY, with a dryslot leading to areas of drizzle
and mist encompassing a large part of the Blacksburg forecast
area. These features will progress east/northeast across the
region through the first half of the evening. Of some concern
for at least our southeast West Virginia counties is that
925-850 mb frontogenetic forcing which lies out ahead of the
deeper colder air pocket. Temps are hovering in the low- mid
30s and there`s some pretty good radar reflectivity returns
showing up across central WV and eastern KY. Between 10 pm and
midnight, we should see rain change to snow showers rather
quickly from western Greenbrier through Mercer Counties, and
into the mountains of northwest NC - with a potential for a
coating to an quick inch of snow with brief reduced visibility.
Following the recent HRRR and the WRF guidance, appears this
precipitation band dries up as the upper low and front move
more northeast. Should be an otherwise dry evening in the
Didn`t make any changes to low temperatures which appear on
track at this point in time.
Previous discussion issued at 330 PM Thursday...
The closed upper low is moving into the Ohio Valley this
afternoon. This is slightly faster than previously forecasted
and has resulted in heavier rain leaving early with temperatures
warming into the mid 30s. However, flow remains easterly along
and east of the Blue Ridge for light rain and drizzle to
continue to fall for the rest of the afternoon. Some isolated
locations are still below freezing and may experience an
additional light glazing of ice.
The closed low is expected to jog to the east this evening
before it tracks northeast along the Appalachians. As winds turn
towards the west, temperatures should warm into the mid to
upper 30s, helping to melt remain ice left on trees. The low is
expected to move quickly to the New England coast overnight.
Modest pressure rises and an increasing cross-barrier jet will
result in breezy and gusty winds tonight into Friday afternoon.
Majority of the ice, should have melted off of the trees before
these northwest winds increase tonight. Also accompany the winds
will be upslope rain showers change to snow showers tonight.
The overall pattern does not suggest any long duration or
significant snow accumulations for western slopes tonight. High
pressure builds in Friday afternoon with winds subsiding.
Temperatures will warm into the 40s across the mountains to the
lower 50s east.
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 115 PM EST Thursday...
Friday night the area will be within an region of decreasing
northwest flow aloft in the wake of the departing upper low and
the approach of surface high pressure. The speeds are expected
to be too weak, that combined with increasing dry air across the
region, to support any lingering upslope isolated rain/snow
showers across western Greenbrier County. Partly cloudy skies
are possible though in this region compared to mostly clear to
clear elsewhere across the forecast area. Low temperatures are
expected to range from the upper 20s to lower 30s across the
mountains with lower 30s across the Piedmont.
Saturday night through Sunday surface high pressure builds
over, then east of the are as the flow aloft becomes zonal.
Expect a continuation of dry conditions and a slight warming
Sunday night into Monday a cold front is expected to reach the
western extent of the area but have little impact on our region
as it progresses eastward. Some parts of southeast West Virginia
will experience some light rain/snow showers late Sunday
afternoon and Night. Temperatures by Sunday night will range
from the low to mid 30s across the mountains with mid to upper
30s across the Piedmont. HIgh temperatures on Monday will reach
the mid to upper 40s across the mountains and mid to upper 50s
over the Piedmont.
Confidence in the above portion of the forecast is moderate to
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 140 PM EST Thursday...
The region will remain near the base of a broad upper trough
that will have periodic weak disturbances progressing across our
area. Model vary as to the timing of these features, but all
are consistent that none will have a huge impact on our
forecast. Most offer some isolated to scattered rain/snow
showers across parts of southeast West Virginia, with limited
coverage, if any, farther east over central or eastern parts of
the forecast area. Our latest forecast will reject such
scenarios with one small potential Monday into Monday into
Monday night, and then again Tuesday night.
The vast majority of the forecast area will receive no
precipitation during this time period. Temperatures during this
part of the forecast will generally range from highs of the low
to mid 40s over the mountains with low to mid 50s across the
Piedmont. Low temperatures will range from the upper 20s to
lower 30s across the mountains with low to mid 30s across the
Forecast confidence in the above portion of the forecast is
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
As of 807 PM EST Thursday...
Largely IFR to LIFR conditions due to low ceilings and/or
reduced visibilities from mist/light fog characterize the TAFs,
and will continue to be the case through the next couple hours.
Will then await the westerly/northwest wind shift associated
with a strong cold front working its way across eastern KY.
Should mostly affect Bluefield with rain changing to snow
showers, with the potential for IFR to LIFR visby in steady
light to moderate-intensity snow between 02-04z. Intermittent
snow showers possible at Lewisburg and Blacksburg but threat
ends by 05z. Westerly wind shift should allow for mixing of fog
out and general improvement in ceilings/visbys to VFR pretty
much from Roanoke eastward after 05z, except residual sub-VFR
ceilings in the mountains (Bluefield and Blacksburg). Winds
variable, will trend westerly and increase to 10-12 kts with
gusts 20-25 kts from Roanoke westward overnight, and around 6-8
kts at Lynchburg and Danville. May see light/moderate chop for
small aircraft around the Blue Ridge overnight as northwest
low-level jet increases to 45 kts.
Any leftover sub-VFR ceilings give way to full VFR areawide
Friday as high pressure noses in. Still pretty breezy with
northwest winds 8-13kts gusts to 20 kts.
Forecast confidence is moderate to high overnight tonight, with
biggest uncertainities being timing and mixover to snow showers
at Bluefield. Otherwise, confidence is high for Friday.
VFR conditions with a mostly clear sky will return across the
region for the weekend. Models suggest a chance for MVFR
ceilings in southeast West Virginia on Friday night and Saturday
morning but confidence is this occurring is low.
VA...Wind Advisory until 9 AM EST Friday for VAZ010>020-022>024-
NC...Wind Advisory until 9 AM EST Friday for NCZ001-002-018.
WV...Wind Advisory until 9 AM EST Friday for WVZ042>044-507-508.