Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/12/22
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
845 PM CST Fri Nov 11 2022
.UPDATE...
Issued at 831 PM CST Fri Nov 11 2022
A ~1200ft-ceiling cloud deck has eroded east of Aberdeen, but, as
alluded to in the previous discussion, is forecast to build back
west over the next several hours. Latest satellite shows this
trend beginning near the ND/SD border. Cloud cover continues to
cling to much of the Missouri River as well, due to the relatively
warm waters. Flurries or light snow will remain possible under
these clouds through the rest of the evening. Also, the HRRR and
several other models build in fog across portions of north central
South Dakota from about midnight into the mid-morning Saturday, as
an axis of sfc high pressure allows for light winds and clear
skies. Have added this to the forecast.
UPDATE Issued at 558 PM CST Fri Nov 11 2022
See below for an updated aviation discussion.
&&
.SHORT TERM...(This Evening through Saturday Night)
Issued at 131 PM CST Fri Nov 11 2022
Clouds and flurries continue this afternoon, mainly east of the
Missouri River. Guidance suggests some continued erosion in the
cloud cover further east into the CWA through 00Z and shortly after,
but then another westward push/development of more cloud cover back
to the Missouri River through the night. So, sky cover reflects
mostly cloudy/cloudy overnight and have continued the flurry mention
into the evening hours. Then, lower confidence exists on what cloud
trends will be into the day Saturday.
At the surface, high pressure will build in tonight and remain in
place through Saturday. Winds will be lighter, which is good for ice
repair/cleanup efforts, but the lack of sunshine for many areas will
be a negative as thick ice buildup remains on several elevated
objects. Basically, the two main challenges in the short term
revolve around temps and clouds. That said, "cold" will be the theme
as we see highs in the teens and 20s, but lows dipping into the
single digits above and below zero. Now, cloud cover could certainly
play a role in this and could see a scenario where overnight lows
may need to be raised because of this.
.LONG TERM...(Sunday through Friday)
Issued at 148 PM CST Fri Nov 11 2022
This entire extended period will feature well below normal
temperatures, with highs in the teens and 20s. A couple of 30 degree
readings will be possible Sunday afternoon over our southern
counties. Even that may be a stretch given the larger variability in
model guidance for Sunday afternoon, with our current forecast near
the higher end, near the 75th percentile. Another predominant
feature will be clouds. While we could get some good clearing
Wednesday, expect more clouds than sun through at least Thursday.
As for the overall weather pattern, we`ll start out at 12Z Sunday
with the exiting ridge over eastern ND/western MN through our far
northeastern counties, as an area of low pressure organizes across
CO. While the surface low sinks south, it will push a trough across
the forecast area during the day Sunday, which will linger over our
eastern counties into Monday. This will be while the next shortwave
trough rotates southeast across our area, as the parent low
stretches from Manitoba through southeastern Canada.
Our next chance of precipitation arrives Sunday evening (20-50%
chance over northeastern SD and west central MN), and lingering over
far eastern SD and west central MN through the day Monday. While
precipitation will stay all in the form of snow, there could be some
slight upslope enhancement on the eastern half of the Sisseton Hills
given the light east wind. Snow to liquid ratios should be around
14:1 (14" of snow for ever 1 inch of liquid precipitation), or in
the dry/fluffy range. Will not be surprised if a couple of locations
accumulate over 1" of snow by mid-morning Monday. The overall trend
is for lower precipitation, and more over our far northeastern
counties.
The 500mb low over Manitoba will sink across ND Tuesday, and over
our forecast area Tuesday afternoon and evening, while at the
surface we`ll be in between the exiting trough and high pressure
across the western Dakotas. Another cold surface high will sink
across the area midweek. An additional 500mb trough may near for the
end of the period, but there is significant differences in the
timing/location/strength.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 558 PM CST Fri Nov 11 2022
Terminals KABR,KATY,KPIR,KMBG
MVFR ceilings are expected to become more entrenched through the
evening and overnight across the area, before improving to VFR through
the morning hours on Saturday. Light snow showers or flurries
remain possible at KABR and KATY this evening, and they may lead
to intermittent reductions in visibility (low chance for MVFR
conditions).
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Lueck
SHORT TERM...TMT
LONG TERM...KF
AVIATION...Lueck
Area Forecast Discussion
National Weather Service Billings MT
549 PM MST Fri Nov 11 2022
.UPDATE...
Clear/dry air mass remains in place and this will lead to another
chilly night...especially east of the foothills. Sheridan has
already fallen from a daytime high of 32F to 12F by 530pm. Miles
City only reached 10F today. Many eastern valleys will again fall
below zero tonight. HRRR gives a strong fog signal over northern
Rosebud and Custer counties, and this seems reasonable given dew
point depressions of only 2F (and there is fog currently in NE
MT). Forecast is in good shape, but did expand fog coverage
beginning at 03z this evening, and have dropped forecast lows in
some eastern valleys. Regarding wind: the northerly flow aloft,
cold air/high pressures west of the divide, and modest mid level
wind speeds are unfavorable for gap flow tonight. Though expect
Livingston to be somewhat breezy, Big Timber and perhaps Harlowton
look like windier places tonight. Expect 30-40 mph wind gusts and
localized blowing snow in these areas. Models also favor
increasing Clarks Fort drainage (15-20, maybe 25 mph) thru the
night, while everywhere east has light winds. JKL
&&
.DISCUSSION...
Tonight through Saturday night...
A ridge of high pressure over the inter-mountain region will mean
another night of chilly northerly flow over our region. This will
keep the cold air entrenched in the eastern valleys. So overnight
lows from 10 below zero to single digits is likely in the east. A
westerly breeze from 10 to 20 mph will keep the foothill areas
to Billings mixed overnight, so lows will range from single
digits to lower teens in the west. Westerly gusts over 30 mph are
possible near Livingston and Nye and may create some patchy
blowing snow, though there is some uncertainty regarding the
strength as models are not in agreement as to the pressure
gradient that may be induced over the foothills. Elsewhere, some
patchy fog is possible again in the eastern river valleys late
tonight (Forsyth to Miles City).
That upper ridge axis will start to shift east Saturday and allow
our daytime highs to moderate a bit more, but still remain below
seasonal averages. The foothills will have the benefit of some
weak downslope to help boost temps. Look for highs ranging from
mid and upper 30s west to the lower 20s east under increasing high
cloudiness late in the day. Temps should not be as cold in the
east Saturday night with most locations remaining above zero in
the single digits. Lower to mid teens are expected in the west. BT
Sunday through Thursday Night...
A dominate upper ridge looks to remain in place over coastal
British Columbia that will keep steep northerly flow over the area
through mid next weekl. Cooler temperatures will stick around that
will be 10 to 15 degrees below normal each day(normal high for
this time of year is ~48). Each afternoon will have a small chance
for very light snow to occur, but no 2+ inch snow events are
expected until Thursday at the earliest. Small windows for breezy
winds can be expected along the foothills, but weak winds aloft
will tame the winds, allowing them to only be influence by
pressure gradients.
Vertz
&&
.AVIATION...
VFR conditions are expected for most locations through tonight.
Brisk westerly surface winds from 10 to 20 kts should be expected
from the foothills to KBIL. Local surface winds at KLVM may jump
back and forth from SW to NW overnight with gusts up to 25-30 kts
when from the SW. There is a slight risk of fog again in the
eastern river valleys including KMLS and KBHK, dropping
visibilities to less than a mile at times late. BT
&&
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
-----------------------------------------------------------
BIL 011/031 010/029 013/033 017/031 018/035 018/027 006/016
00/B 02/S 13/J 41/B 10/B 25/J 31/B
LVM 011/039 014/034 013/035 018/036 017/040 018/030 004/020
00/Q 01/B 02/J 20/B 10/B 34/J 31/B
HDN 906/028 004/029 008/032 015/029 009/034 013/028 001/016
00/B 03/S 24/J 52/J 11/B 35/J 32/J
MLS 909/019 007/023 011/027 014/023 007/027 013/024 903/011
00/B 02/S 23/J 42/J 11/B 24/J 21/B
4BQ 903/034 011/025 014/029 017/026 010/030 015/026 003/015
00/U 01/E 13/J 53/J 11/B 24/J 21/B
BHK 907/026 007/021 009/023 008/020 004/024 011/022 903/011
00/B 01/E 12/E 31/E 11/B 23/J 11/B
SHR 001/039 011/030 010/034 017/031 012/037 015/030 003/018
00/U 02/S 23/J 63/J 11/B 25/J 42/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service State College PA
1030 PM EST Fri Nov 11 2022
.SYNOPSIS...
The remnants of Tropical Storm Nicole will merge with an
approaching cold front and push through central Pennsylvania
tonight. Rain will taper off early Saturday morning with
temperatures trending colder through the remainder of the
weekend. Periods of rain and snow showers are likely downwind of
Lake Erie over the western and central Alleghenies through
Monday morning.
A Gulf Coast storm system could impact the area with rain or
snow later Tuesday into Wednesday. Following a very mild start
to November, a rather cold pattern is expected to be in place
next week with above average confidence in below normal
temperatures.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The remnants of Tropical Storm Nicole has merged with an approaching
cold front, which is entering the the Allegheny Plateau at 03Z.
MRMS multisensor QPE through 01Z has ranged from around 3 inches
over Warren County, where the rain is now tapering off, to
between 0.5 and 1 inch over the north central mountains and
Lower Susq Valley. Latest convection-allowing models, which
should perform fairly well in the region of strong forcing ahead
of approaching trough, target the north central mountains for
the heaviest rain overnight. Anomalous +4SD pwats, combined with
strong fgen forcing beneath right entrance of upper lvl jet
streak, should support a band of moderate to heavy rain lifting
from the Alleghenies at 03Z northeastward into upstate NY after
midnight. Latest HRRR suggests 1.5 to 2 inches of additional
rain is possible over the north central mountains overnight.
However, given the relative lack of rain in this area so far and
dry antecedent conditions, believe the threat of anything more
than localized, poor-drainage area flooding remains fairly low.
Strong shear and marginal instability could potentially support
a few thunderstorms over the southeast part of the forecast
area in the 03Z-07Z time frame. Given the strong shear, can`t
rule out a few low-topped supercells over the Lower Susq Valley.
However, upstream convection over northern Virginia suggests the
risk of severe weather is low.
Large scale subsidence in wake of the front should result in
clearing skies east of the Alleghenies late tonight. Residual
low level moisture and upsloping westerly flow should cause low
clouds to persist over the western counties.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Medium range guidance supports a shift to much colder
conditions this weekend, as upper trough builds in behind
the departing sfc cold front.
Large scale subsidence, as inferred by model 300-500mb QVEC
convergence fields, should lead to dry weather in the 12Z-18Z
period Sat, with a fair amount of sunshine east (downwind) of
the Alleghenies. A potent shortwave rounding the base of
an upstream trough is progged to lift across western Pa Saturday
afternoon. Forcing ahead of this feature, combined with a
deepening/moistening boundary layer and upslope flow into the
Alleghenies, should lead to thickening clouds and a good chance
of rain showers over the western half of the forecast area.
Model soundings suggest the air mass could be cold enough for a
few wet snowflakes over the higher terrain west of rt 220.
Models have trended slightly more to the west with this feature
over the past few runs, so 0.01 - 0.02 of an inch may be the
most the central ridge and valley region sees in the 20Z Sat
-00Z Sun timeframe, while several hundredths of an inch (to
possibly 0.10 of an inch) could occur near and to the west of
the RT 219 corridor.
Lake effect snow showers then appear likely over the NW Mtns
Saturday night into Sunday, as upper trough axis swings through
and boundary layer flow veers to the northwest. Current guidance
suggests a light snow accumulation is likely over the northwest
mountains.
Falling inversion heights are indicated Sunday night/Monday, but
cold northwest flow should cause lighter snow showers/flurries
to persist across mainly the NW Mtns.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A few lake effect snow showers/flurries could linger into early
Monday. Otherwise, all medium range guidance supports fair
weather Monday into early Tuesday, as upper ridge builds over
the state.
Short wave trof is forecast to round the base of the western
upper trof and trek across the srn border of the CONUS, pass
along the GOMEX coast and lift into the middle atlantic region
by the middle of next week/end of the long term period. A
blocking high over New England should provide the cold air for
potential wintry precip over part of central Pa, as this feature
lifts through late Tuesday into early Wed. Continued to bump up
POPs for midweek with this system with rain over the southeast,
a mix of rain/snow over central PA and the best chance for all
snow over the northwest.
Upper level troughing and a seasonably chilly west-northwest
flow over the still mild waters of the Grt Lks should support
lingering lake effect snow showers across the NW Mtns the second
half of the week. Elsewhere, late next week looks chilly and
dry. Ensemble mean 850 temps around -9C should translate to
highs from the low and mid 30s over the higher terrain of the
Alleghenies, to the mid 40s across the Lower Susq Valley.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As the remnants of Nicole continue to push northeastward towards
PA tonight, a second batch of moderate rain associated with the
deformation band on the NW side of the storm system will move
into western and central airfields. There may be enough
instability over eastern airfields (MDT, LNS) for a rumble of
thunder as the cold front moves through between 05z-09z, but
left the mention of thunder out of the TAFs for now due to chances
being low.
Widespread MVFR or IFR conditions were reported at 00z Sat.
Conditions will likely worsen to IFR for many additional
airfields during the first part of the night as the second batch
of rain moves in, but there will be some improvement back to
MVFR over eastern airfields before sunrise as drier air moves in
behind the cold front.
The cold front will turn the winds to the WNW around 06Z in
BFD-JST, and around 09Z Sat at IPT-MDT. LLWS will continue ahead
of the cold front with southerly flow up to 45 kts at 2kft
within the LLJ, but the LLWS threat will diminish behind the
cold front. WNW winds will gust up to 25 kts behind the cold
front into the day on Sat.
Cigs and vsby will continue to improve over central and eastern
airfields during the day Saturday, but will likely stay IFR or
lower across the Alleghenies (BFD, JST) much of the day. A
secondary shortwave trough will bring another round of rain and
even some wet snow to the Alleghenies by 18-21z Sat, which could
result in further reductions in cigs/vsby.
Outlook...
Sat...Early AM rain/low cigs. Evening rain/snow showers and low
cigs possible W Mtns.
Sun...Lake-effect snow showers/VIS reductions possible NW Mtns.
Mon...No sig wx expected.
Tue...PM light rain/snow possible, mainly south.
Wed...Lake-effect snow showers/VIS reductions possible NW Mtns.
&&
.EQUIPMENT...
KCCX will be offline from 11/10 to 11/17as the backup generator
and electrical system at the site are upgraded. This upgrade
and refurbishment is part of the WSR-88D Service Life Extension
Program (SLEP).
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Fitzgerald
SHORT TERM...Lambert/Fitzgerald
LONG TERM...Fitzgerald
AVIATION...Colbert/RXR
EQUIPMENT...
Area Forecast Discussion
National Weather Service Green Bay WI
541 PM CST Fri Nov 11 2022
Updated aviation portion for 00Z TAF issuance
.SYNOPSIS...
Issued at 238 PM CST Fri Nov 11 2022
A cold period with lake-effect snow showers in the Lake Superior
snowbelt at times. A round of light wintry precipitation is
possible across the entire area Tuesday into Wednesday.
An rather amplified but somewhat split and disjointed flow regime
across North America will undergo consolidation and further
amplification during the period, evolving toward a pattern with a
strong/sharp ridge along the West Coast and a broad, deep
downstream trough across the middle of the continent. The pattern
will provide a continuous feed of cold, polar air from high
latitudes into the central CONUS, resulting in below normal
(generally 6-11 F degrees) temperatures throughout the period.
Lake-effect combined with disturbances rotating through the
large-scale trough will bring precipitation to the area at times,
and most of it should be wintry. But with gulf moisture remaining
shunted southeast of the area, the 7-day total precipitation will
be below normal.
&&
.SHORT TERM...Tonight and Saturday
Issued at 238 PM CST Fri Nov 11 2022
The latest RAP analysis and satellite/radar imagery show low
pressure exiting the region over Lake Huron early this afternoon.
Tight cyclonic flow remains over the western Great Lakes behind
this cyclone as a surface trough extends west from the low and
into northern Minnesota. As a result of this cyclonic flow and
ongoing strong cold advection, widespread cloud cover extends
across north- central and northwest Wisconsin. Snow showers have
mainly remained over the Upper Peninsula to western Lake Superior
so far today, but that could change by late this afternoon when
winds veer to the northwest with trajectories off Lake Superior.
These trajectories will set the stage for lake effect snow showers
over far northern WI tonight into Saturday, with potential
accumulations as the primary forecast concern.
Tonight...Moderate northwest to north winds will continue within
cyclonic flow. Wind trajectories become more favorable for
accumulating lake effect snow over far northern WI this evening,
before trending too northerly overnight. The gradual veering wind
profile will likely limit potential accumulations despite delta
T`s reaching close to 20C over western Lake Superior. 1 to 2
inches appears (locally higher amounts) possible over northern
Vilas by early Saturday morning, while areas further south and
east see a dusting to a half inch of accumulations. Light snow
and/or flurries could extend further south late tonight as
saturation depth increases, thus extended the flurry mention
across the rest of the region after 3 am.
Saturday...Cold, breezy northerly flow will continue across the
region. Saturation depth will gradually increase through the day
in response to large scale ascent from a digging upper trough.
Combined with weak low level instability, conditions will become
more favorable for scattered convective snow showers with daytime
heating away from the lake effect belt. Most accumulations should
remain over far northern WI though with another 1-2" possible
over northern Vilas county. Below normal temps ranging from the
upper 20s to middle 30s.
.LONG TERM...Saturday Night Through Friday
Issued at 238 PM CST Fri Nov 11 2022
The lake-effect event in the Lake Superior snowbelt will continue
Sunday night and into Monday, but should be waning as large scale
forcing begins to favor subsidence and the flow across the lake
weakens.
The medium range models sharpen the large-scale trough across the
area during the Tuesday to Wednesday time frame. There is a hint
of some phasing between a southern stream shortwave and energy
dropping south from ON/MB. The GFS was the most aggressive with
the phasing, trying to develop a surface cyclone back in the cold
air mass over the Lake Erie region. The ECMWF and Canadian were
less aggressive, but still showed surface troughing lingering back
into the area from a system riding through the Ohio or Tennessee
Valley region. The less aggressive solutions seem more reasonable.
Even so, there will probably be periods of light precipitation
across the area. Temperatures should be cold enough for snow--except
perhaps near Lake Michigan where easterly flow will warm the
boundary layer and result in a rain/snow mix. Snow amounts will be
light, but it may be the first round of snow covered roads across
the area so it seemed worthy of a mention in the HWO.
Generally quiet but cold weather is expected for the rest of the
period, though some snow showers will be possible in the Lake
Superior snowbelt depending on the wind direction.
Went above the NBM for mins for the N/NE part of the area
Saturday night due to the expected north flow across Lake
Superior. Otherwise, stayed close to the NBM for temperatures.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 533 PM CST Fri Nov 11 2022
Abundant low-level moisture and cyclonic NW-N flow around a
departing low pressure system will generate widespread broken to
overcast low clouds through the TAF period. While clouds may rise
to VFR at times due to downsloping NW flow in northeast
Wisconsin, mainly MVFR cigs are expected over central and north
central WI. Lake-effect snow showers will increase in far north
central WI this evening and continue through Saturday. This area
will likely see minor accumulations, with 1 to 3 inches likely
over northern Vilas county. A short-wave trough will cause
scattered snow showers and flurries to overspread the rest of the
forecast area during the late morning and afternoon.
NW-N winds will gust to 15 to 20 knots through the period.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS.......Skowronski
SHORT TERM.....MPC
LONG TERM......Skowronski
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Gray ME
1042 PM EST Fri Nov 11 2022
.SYNOPSIS...
A complex frontal system will interact with the remnants of
tropical system Nicole tonight and into Saturday morning as the
system tracks northeast. This keeps the heaviest rain west of
the forecast area while locally heavy rainfall rates and gusty
winds remain possible mainly across the upslope higher terrain.
A few additional showers will be possible Sunday and Sunday
night before high pressure brings drier and seasonably cool
weather for early next week. A coastal low may cross the region
midweek.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1040 PM Update...Heavy rain showers have overspread most of the
forecast area as of this writing with measured hourly rainfall
rates of around a half inch at times, a few locally up an an
inch. This is aided by PWATS approaching 1.8 inches across
southern zones which is likely unprecedented for this late in
the year. The good thing is that the heaviest rain elements are
quite transient and moving along quite well on the strong LLJ.
This will aid in heavily reducing the threat for serious
flooding.
Local ponding of water is expected any may flood some roads
especially the more susceptible ones. However, dry slot
approaching from the south will effectively cut off the
widespread heavy showers after 06z-07z or so with just more sct
precipitation and even some drizzle and fog through Saturday 15z
or so. Can`t rule out an isold thunderstorm overnight.
Winds not an issue at this time with strong low level inversion
in place. Could see an increase with local gusts 30 to 40 MPH
late, especially on the Midcoast of Maine. At this time,
widespread strong winds are not expected.
As low level heat and moisture advect northward overnight with
SFC warm front, temperatures will likely rise in many areas with
a really soupy feel to the air expected by the time most people
are waking up.
Previously...
630 PM Update...Forecast remains on track with temperatures,
winds, and precipitation arrival. Very little change to the
going forecast. The heaviest rain continues to look to fall
between roughly 9 pm and 4 am before it pretty much shuts off
from south to north. After that we`ll await the second batch of
rain and possible thunder between 7 and and noon from west to
east.
Previously...
An upper trough over the Great Lakes will slowly advance eastward
this evening into Saturday along with a cold front at the surface.
The remnants of Nicole will track from the interior Mid Atlantic
northward this evening with favorable upper dynamics leading to an
organized area of low pressure forming along the eastward advancing
cold front. This area of low pressure will deepen as it tracks
northeastward near the St Lawrence Valley late tonight with its
attendant cold front sweeping across the area early Saturday
afternoon.
There is good agreement amongst the 12Z guidance that an initial
batch of moderate to locally heavy rain will overspread the region
from SW to NE through this evening associated with warm air
advection. This initial batch will be followed by a dry slot moving
in from the SW after midnight. This dry slot will likely lead to
much of the area seeing an end of steady rain for several hours
before a secondary area of moderate to locally heavy rain moves
across the area with the cold front after sunrise.
CAMs continue to show some elevated instability with the initial
batch of rain tonight and have continued the mention of thunder
in the forecast. Convective processes combined with high PWATs
will bring the threat for locally heavy bouts of rain. While the
best forcing and axis of heaviest rain still remains well west
of the forecast area, some CAMs including the last few runs of
the HRRR are suggesting a secondary axis of heavy rain in excess
of 2 inches along the coast or just offshore from training
convection. This is at odds with other guidance that is more of
a widespread 1-2 inches with up to 3 inches in the White
Mountains. Have tried to massage some of these most recent
trends into the rainfall forecast for tonight while not
deviating too far from the collaborative QPF process. Thus, the
going forecast through tonight is for 1-2 inches of rain across
the area before the second round of rain moves through with the
cold front Saturday morning. There will also likely be patchy
fog across the area as low level moisture increases with
dewpoints climbing into the low to mid 60s by late tonight
making for a very warm and humid November night.
As has been the case for the last several forecast cycles, a strong
southerly LLJ jet with winds around 60 kts between 2KFT and 4KFT
will slide eastward across the area tonight into Saturday morning.
Momentum transfer algorithms continue to indicate that these winds
will struggle to mix down to the surface, although convection
coinciding with the LLJ could mix some of these winds down in the
heaviest cells. The going wind gust forecast is for peak gusts to
top out around 30 mph inland and closer to 40 mph near the coast
with isolated stronger gusts from winds aloft mixing to the
surface.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Around daybreak Saturday much of the forecast area will be in the
dry slot with WAA precipitation exiting Downeast Maine and the cold
front pushing across the Hudson Valley. Southerly winds will
still remain elevated through the morning hours before the cold
front crosses late morning and early afternoon bringing a wind
shift out of the WNW. Most CAMs show a convective fine line
along the cold front over the Hudson Valley Saturday morning
with a general weakening trend of this fine line as it
approaches the CT Valley around 8 AM. This fine line feature
will be something to watch for potential strong winds as it
crosses NH and western Maine through late morning with
additional bouts of moderate to heavy rain. The cold front will
exit to the east Saturday afternoon with clearing skies south
of the mountains. Across the mountains and north clouds and
upslope showers will continue through the afternoon. There will
also be a good push of wind out of the WNW behind the front with
gusts around 30 mph. Total QPF from overnight through Saturday
morning is a widespread 1 to 2 inches with up to 3 inches in the
mountains. Will continue to monitor trends through tonight to
see if rainfall amounts should be increased near the coast per
the latest trends of the HRRR mentioned above.
Saturday afternoon looks to be quite nice south of the mountains
with sunshine and temperatures in the upper 60s to near 70
degrees. It actually may also feel quite sticky with dewpoints
still in the low 60s. WNW winds through the afternoon and
evening will usher in drier air into tomorrow night with
dewpoints falling into the 40s. Lows Saturday night will be much
lower than tonight as temperatures drop into the upper 30s to
mid 40s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Scattered showers will move across the region Sunday into Sunday
evening as an upper level trough pivots through New England.
Temperature profiles suggest that some of the precipitation will
mix with snow showers across the highest terrain in the north.
In fact, several operational models and ensemble solutions
suggest a surface low will develop Sunday and intensify as it
exits through the Gulf of Maine Sunday night. This system has
the potential to throw back a period of heavier precipitation to
far northern and eastern areas and this possibility will need
to be monitored as the ptype in northern areas will become
primarily snow.
Windy conditions can be expected Monday as Canadian high
pressure builds into New England. Northwesterly winds will allow
for more cloudiness in the upslope areas of the higher terrain
and additional sunshine for downslope regions. Models suggest dry
conditions will continue on Tuesday with diminishing winds along
with seasonable temperatures.
Models continue to suggest low pressure may move up the
Northeast coast on Wednesday into Wednesday evening. With
surface temperatures expected to be in the 30s across the north,
snow remains a possibility. Some snow may mix in with the rain
for a period over central areas as well. In any case, the week
will end with chilly and blustery conditions for the forecast
area.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
Short Term...IFR/LIFR conditions last through Saturday morning.
Strong southerly winds will bring LLWS around 40KTs at 2KFT
from shortly after sunset through sunrise. A cold front crosses
mid to late morning with a drying trend Saturday afternoon and
conditions improving to VFR with WSW gusting to 25 kts.
Long Term...MVFR conditions can be expected for most of the
region on Sunday and into Sunday evening in rain showers mixing
with snow showers over northern areas. In between the periods
of low clouds and precipitation VFR conditions can be expected,
especially over western New Hampshire.
VFR conditions will dominate the region on Monday as
northwesterly breezes continue. Winds will become light on
Tuesday as a ridge of high pressure crosses the region. By
Wednesday, low pressure moving up the coast will bring
widespread IFR conditions to the region with mixed rain and
snow.
&&
.MARINE...
Short Term...Southerly winds ramp up this evening and will reach
Gale force around midnight tonight. A cold front crosses mid day
tomorrow with winds shifting out of the WNW with continued
potential for Gale force winds until late afternoon. Thereafter,
winds drop below 25 kts Saturday night while seas remain
elevated to 5 to 9 feet and gradually subside towards Sunday
morning.
Long Term...Even though winds will diminish through the day on
Sunday, SCA conditions will continue outside of the bays with seas
of 4 to 7 ft. After that, northwest winds will ramp right back
up Sunday night into Monday with gusts over 25 kt prolonging the
SCA conditions. By Tuesday, winds and seas will subside as high
pressure settles into the region. A coastal low may approach
the waters toward the middle of next week.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Gale Warning until 5 PM EST Saturday for ANZ150>154.
&&
$$
SYNOPSIS...
NEAR TERM...Ekster
SHORT TERM...Schroeter
LONG TERM...Cannon
AVIATION...
MARINE...
Area Forecast Discussion
National Weather Service North Platte NE
634 PM CST Fri Nov 11 2022
...Aviation Update...
.SHORT TERM...(This evening through Saturday night)
Issued at 316 PM CST Fri Nov 11 2022
1032 mb high pressure centered over wrn SD/ND this afternoon will
ridge south into cntl Nebraska tonight setting the stage for light
drainage winds and strong radiational cooling. The models show
precipitable water at 0.10-0.15 inches and h850-300 mb RH at or
below 30 percent. There is a slight chance the MVFR ceilings across
ern SD will back into ncntl Nebraska negating radiational cooling in
that area but the cloud cover shown in the RAP and SREF models could
be an artifact of the strong radiational cooling and near-sfc
saturation.
The forecast assumes the strong high pressure and subsidence will
produce generally clear skies. The guidance blend suggested
widespread lows in the single digits to near zero. This forecast is
slightly warmer than the coolest guidance, the MET guidance, but
splits with the NBM 50th percentile which is cooler north, and
warmer south.
Very dry air will remain across wrn and ncntl Nebraska Saturday but
then moisten up Saturday night as the high pressure builds east into
the MO-IA-MN midwest region. The guidance blend, which was warmer
the than the NBM 50th, suggested highs in the 20s, 30s and 40s. A
warm front will push east, part way into wrn Neb. The front will
continue to progress east Saturday night. The warm air advection
favored short term model blend suggested lows mainly in the teens
with south winds developing overnight. This forecast is very close
to the NBM 50th.
.LONG TERM...(Sunday through Friday)
Issued at 316 PM CST Fri Nov 11 2022
1037 mb sfc high pressure centered over nrn Manitoba will
build south with the leading edge of the cold air arriving in wrn
and ncntl Nebraska Sunday night. This, in response to an upper level
low off the coast of Oregon tracking into nrn Texas by Monday
morning. The model consensus maintains the associated winter weather
across CO/KS and pts south but the NAM and SREF are farther north
presenting srn Nebraska with light snow. The forecast is dry for
now but this is certainly worth watching considering the
aforementioned high pressure will build very slowly south through
the Great Plains Monday through Wednesday. Any snow cover would have
a negative impact of temperatures on the order of 5 to 10 degrees.
The next item of interest is the arrival of a reinforcing arctic
cold front Thursday. The models continue in very good agreement
amplifying heights across the north Pacific and into AK. A strong
1050+ mb high pressure system will form across the Yukon territory
by Wednesday morning which will be driven due south through the high
Plains and the Rockies Thursday and Friday. Both the GFS and ECM
show snow behind the arctic front Friday supported by a plume of
upper level moisture moving in off the Pacific. The moisture and the
midlevel frontogenesis supports the 6 to 12 hour period of light
snow shown by the models. The current forecast is very conservative
suggesting just a slight chance of snow next Friday. This is
probably warranted given the snow is 7 days out in the forecast.
Highs in the 20s, 30s and 40s are in place Sunday and beyond but it
is worth noting the caliber of cold air moving through Nebraska next
week. Temperatures at h700mb are expected to fall to -15C to -20C
Wednesday and Friday; -12C to -18C are predicted at h850mb. These
numbers are above the 90th percentile and close to record low
according to the SPC sounding climatology. The only thing holding
back record lows and record low highs will be snow cover.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 633 PM CST Fri Nov 11 2022
VFR conditions will prevail through Saturday across all of western
and north central Nebraska. Winds will be light tonight and
Saturday as well.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Taylor
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
931 PM CST Fri Nov 11 2022
.UPDATE...
Issued at 930 PM CST Fri Nov 11 2022
Regional radars is showing that precipitation has moved into
southern Missouri this evening with rain being reported at
Branson in the last hour ahead of mid-level shortwave currently
over the Plains. Current forecast looks on track with the
precipitation moving northeast into the southern CWA late this
evening into the overnight hours. Latest RAP soundings at FAM
still are cold enough support snow during this time frame, but
low SLRs and warm ground temperatures should keep any snow
accumulations minor along and south of a Centerville, MO to Salem,
IL line.
Clouds have held together moving south of Iowa this evening, so
did increase cloud cover the rest of the night. Made minor
temperature adjustments based on observations.
Britt
&&
.SHORT TERM... (Through Late Saturday Night)
Issued at 208 PM CST Fri Nov 11 2022
Today we see a large scale trough across the Great Plains with a
ridge on either coast. Yesterday`s cold front is merging with the
remnants of former Tropical Storm Nicole over the Appalachians.
Surface high pressure is building in over the northern plains, with
our area seeing cold and dry advection on a northwesterly wind.
For tonight, a wave rotates through the base of the upper trough
across Texas and Oklahoma and toward the Mississippi River. This is
expected to spread some light precipitation eastward through the
overnight period. It`s looking increasingly likely that the far
southern part of our forecast area will get in on at least some
light precipitation associated with this overnight. The temperature
at all levels will be below freezing, with the forcing for this
precipitation being generated at 700 MB and above. Thus snow will be
the precipitation type expected. With a significant amount of dry
air beneath this forcing layer, we expect that overall amounts will
be held down somewhat with snow ratios not being very efficient.
That said, the likelihood of at least some snow has increased, and
at this stage we expect that a dusting of snow is likely across
southeast Missouri into southern Illinois with up to 1 inch
possible. Some snowflakes could fall as far north as St Louis,
although accumulations that far north are unlikely. This will exit
quickly to the east Saturday morning as the upper trough axis shifts
east.
Saturday will likely be the coldest day of this air mass as the
core of the cold air will be over our region. Highs will only make
it into the 30s with lows Saturday night falling off into the
teens to low 20s. Surface high pressure moving across the area
will lead to good radiational cooling conditions, so some
typically colder spots could be even colder.
Kimble
.LONG TERM... (Sunday through Next Friday)
Issued at 208 PM CST Fri Nov 11 2022
While the initial trough moves east, another one drops down through
the intermountain west helping to reinforce the overall troughing
across central North America. This next wave will eventually track
across the southern tier of the country and bring our next chance of
precipitation early next week. In the meantime, surface high
pressure slowly moves across the Mississippi Valley on Sunday with
sunshine helping to moderate the air mass in place. Temperatures
will be about 5 degrees warmer on Sunday, in the upper 30s to low
40s. As the surface high shifts even a bit further to the east on
Monday we`ll moderate even further into the mid 40s on Monday, but
by then we`ll start to see some increasing clouds in advance of
the next wave.
The next shortwave trough tracks east out of New Mexico into Texas
on Monday and then ENE into the Mississippi Valley by Tuesday
morning. It will be a highly tilted system, with the surface low
tracking along the Gulf Coast while the 700 and 500 MB waves track
through Missouri and Illinois. It`s become increasingly likely that
we`ll see a period of snow across just about our entire forecast
area late Monday night into Tuesday morning. Model consensus is high
on this idea, although intensity varies. Precipitation type is also
fairly certain with snow likely. Surface temperatures near or above
freezing at the start and end of the precipitation may allow for
some rain, but the core of this should be snow given cold
temperatures aloft and our position so far north of the surface
wave. With growing consensus in ensemble forecasts of at least light
precipitation amounts, we have increased the POP for this time range
to reflect the growing confidence.
The biggest question with the Monday night/Tuesday wave will be with
snowfall amounts. With the surface wave tracking so far south and
moving relatively quickly, we won`t have a whole lot of moisture to
work with. As a result, most model solutions keep amounts fairly
light with forcing focused in the mid and upper levels of the
atmosphere favoring poor snow ratios. The GFS is a notable outlier
in producing heavier amounts during this period. This is likely due
to a more pronounced 500MB wave which leads to greater forcing and
moisture transport northward ahead of it. The overall consensus is
growing, however, that we are likely to see our first accumulating
snowfall of the season, with amounts likely to be light but
significant enough for travel impacts. Timing of snowfall looks to
be roughly from midnight Monday night through mid morning on Tuesday.
Beyond this, cool conditions continue. Another shortwave trough
dives down through the Great Plains behind the departing wave
helping to reinforce the cold air that`s already in place.
Temperatures are likely to remain 10 to 20 degrees below normal
through the end of the week with no other significant precipitation
likely.
Kimble
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 518 PM CST Fri Nov 11 2022
Winds are expected to remain out of the northwest through the
period with some gusts to near 20 knots at the St. Louis area
terminals. MVFR ceilings are expected to move out the UIN by 01Z.
Low VFR ceilings are expected to move back into UIN and the St.
Louis area terminals by mid morning on Saturday.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
544 PM CST Fri Nov 11 2022
...New AVIATION...
.DISCUSSION...(This evening through next Thursday) Issued at 315
PM CST Fri Nov 11 2022
A strong cold front has made its way across the Midsouth.
Temperatures have been steady or falling across the area for
several hours. Much of northeast Arkansas and the Missouri
Bootheel are in the middle 50s while a small portion of northeast
Mississippi remains in the middle 70s. Clouds have spread east of
the Mississippi River and should overspread the remainder of west
Tennessee and north Mississippi over the next few hours. Strong
CAA will result in plummeting temperatures tonight. Expect morning
lows in the low to middle 30s, in some instances 40 degrees
colder than todays high temperature.
Our first winter event of the season is in the works for tonight
as a deep trough swings across the Mississippi River valley. Rain
should start after sunset to the southwest of Memphis and spread
to the northeast. Nearly all of the Midsouth should see rain by
midnight with a changeover to a wintry mix beginning shortly
after midnight. The freezing line does not look like it will make
it to Memphis, but it should make it through Jonesboro, AR and
Jackson, MS. The GFS and the HRRR both take all of the
freezing/frozen precipitation into Middle Tennessee shortly after
12z while the ECMWF takes a couple more hours. Some rain may
linger in north Mississippi until mid morning.
Probabilistic NBM guidance has increased the chance of greater
than an inch of snow from zero to about 10% for far northeast
Arkansas, the Missouri Bootheel and along the Kentucky state line
in Tennessee. The chance of any snow ranges from about 50% to 75%
north of the I-40 corridor, highest in the same area mentioned
above. Deterministic guidance is about the same as it was
overnight, NAM and the GFS still only produce trace amounts, the
ECMWF has about one half of an inch maximum with trace amounts
almost as far south as Jackson, TN, Tipton county, TN and Poinsett
county, AR. The HRRR (Kuchera method) produces trace amount
another county or two farther south with a narrow corridor of up
to an inch in the Missouri Bootheel into Lake county, TN. Using a
simple 10:1 ratio the HRRR maxes out at about 0.5 inches. Lastly,
WPC`s Winter Weather desk paints a corridor of 0.1 inches to 1
inch north of a line from near Jonesboro, AR to Union City, TN.
Given QPF totals generally less than 0.15 inches while
temperatures are near or below freezing, feel comfortable keeping
accumulations below one half of an inch. We should also keep in
mind that we have been abnormally warm for the last few weeks.
Two-inch soil temperatures remain in the mid 60s across northern
portions of the Midsouth, so actual accumulation of any amount may
be more difficult that models are predicting.
By mid afternoon, clear skies should return to all of the
Midsouth. A transient ridge will keep us cold and dry Saturday
afternoon through Monday. Expect high temperatures in the middle
to upper 40s. A north breeze generally 10-15 mph will result in
wind chills in the 30s across much of the area.
Sunday will be just as cold, possibly even colder but with less
wind chill and sunny skies all day.
Another storm is expected Monday night as another deep trough
moves quickly across the middle and lower Mississippi River
Valley. Rain should start after sunset and end mostly by Midday
Tuesday. Temperatures should be a little warmer than with the
system tonight so any wintry precipitation should be confined to
far northeast Arkansas and the Missouri Bootheel.
For the rest of the work week surface high pressure will build in
from the west keeping us cold and dry. The late week storm in
previous model runs no longer looks likely but a dry cold front
should bring our morning low temperatures back in the 20s or low
30s.
30/Sirmon
&&
.AVIATION...
(00Z TAFS)
Issued at 534 PM CST Fri Nov 11 2022
Primary concern remains mixed wintry precip along and north of a
MEM/MKL line after 08Z. Short range model consensus remained
consistent with respect to timing and precip type. Resident period
of mixed winter precip for MEM appears short, with drying of the
column by 11Z. In addition, surface temps at MEM will prevail
above 0C through the TAF period.
For the daytime hours Saturday, main impact will remain gusty
north winds, with a gradual MVFR-VFR transition toward midday.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...JDS
AVIATION...PWB
Area Forecast Discussion
National Weather Service Phoenix AZ
400 PM MST Fri Nov 11 2022
.UPDATE...
Updated Aviation
&&
.SYNOPSIS...
Mainly tranquil weather conditions will prevail through the next
several days. Below normal temperatures with highs in the upper 60s
to around 70 degrees are expected through next week with Saturday
being the warmest day with highs in the low 70s. A mostly dry
weather system will move across the region Sunday into early Monday,
only bringing another round of breezy conditions. Otherwise,
precipitation chances will essentially remain zero through at least
the next 7 days.
&&
.DISCUSSION...
Latest RAP streamline analysis depicts a shortwave ridge migrating
steadily eastward across the Desert Southwest. Early afternoon ACARS
KPHX soundings reveal relatively cool and dry air resides in the
lower levels below a well-defined subsidence inversion at 600 mb.
Despite the nearly full sunshine, temperatures are running roughly
10 degrees below average for this time of year.
Further upstream, a well-defined low pressure system is evident
across the Pacific Northwest. Ahead of this system, latest HREF
indicates high clouds will overspread the area late this afternoon
and tonight. Mostly sunny skies are anticipated again Saturday along
with slightly warmer conditions. However, temperatures will remain
roughly 5 degrees below average.
A cooling trend is likely Sunday as the aforementioned low pressure
system drops southeastward into northern Arizona. Given the dearth
of adequate moisture transport, multi-model ensemble remains
consistent indicating only a chance of very light precipitation
across northern Arizona. Biggest sensible impact instead across the
lower deserts will be an increase in wind, particularly across
portions of southeastern California and southwestern Arizona where
gusts up to 30 mph will be possible. Across the Phoenix area, latest
experimental NBM suggests gusts will likely reach 25 mph during the
afternoon. In the wake of the system, high temperatures Monday will
struggle to reach the mid 60s across the lower deserts of central
Arizona. Low temperatures in the 30s are also anticipated in the
Globe/Miami area Sunday night and Monday night, though the
probability of freezing temperatures remains below 15 percent, per
the latest experimental NBM. However, with overnight RHs likely
reaching 60 percent, there is a somewhat higher probability of frost
in these areas.
&&
.PREVIOUS DISCUSSION...
As we head into next week, the overall weather pattern across North
America will be characterized by a robust blocking ridge being
established over the eastern Pacific into Alaska. This will result
in broad troughing across much of the CONUS and thus the
continuation of below normal temperatures. As a result, temperatures
through next week will remain on the cool side with highs in the
upper 60s to around 70 degrees and overnight lows in the 40s across
the lower deserts. These values will be a good 7-10 degrees below
normal. In addition to the cool temperatures, dry conditions will
continue with no noticeable weather features on the horizon to
result in the potential for precipitation.
&&
.AVIATION...Updated 2300Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No weather concerns will exist through Saturday afternoon under
periods of high clouds. While the typical nocturnal easterly winds
and diurnal west winds will arrive, speeds will be under 8kt and
prolonged periods of nearly calm conditions will be common.
Southeast California/Southwest Arizona including KIPL and KBLH:
No weather issues will exist through Saturday as high cirrus clouds
slowly clear. Light N/NW winds will be preferred through the
overnight with extended periods of variable directions more common
Saturday afternoon.
&&
.FIRE WEATHER...
Mainly dry weather conditions will prevail through at least the next
7 days with temperatures remaining well below normal, with highs
generally in the upper 60s to around 70 degrees across the lower
deserts. Winds will remain fairly light today and Saturday, however,
a fast moving weather system moving through Sunday into early Monday
will result in another round of breezy conditions, especially across
portions of southeast California and the Lower Colorado River
Valley. MinRH values during the next several days will generally
range between 15 and 25% areawide.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Lojero
AVIATION...18
FIRE WEATHER...Lojero
Area Forecast Discussion
National Weather Service Blacksburg VA
1004 PM EST Fri Nov 11 2022
.SYNOPSIS...
Rain will come to an end overnight as remnants of Nicole tracks
through the Mid Atlantic region. A strong cold front will cross
the area on Saturday, ending the precipitation Saturday night,
but bringing in more wind and much colder air. Dry weather and
below normal temperatures temperatures are expected Sunday and
Monday under high pressure.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1004 PM EST Friday...
Cancelled the flood watch for portions of southwest Virginia and
northwest North Carolina with widespread heavy rain ended. Flood
warnings remain in effect for Ashe and Watauga county tonight.
Made some minor adjustments in temperatures and pops for tonight
into Saturday morning. Shaped pops tonight towards a blend of
HRRR and NamNest.
previous:
As of 655 PM EST Friday...
Flood watch remain in effect until 1 AM EST Saturday for
VAZ015>017-032 and NCZ001>003-018-019.
Allowed the wind advisory to expire at 7 pm across the southwest
mountains with wind gusts this evening expected to remain below
advisory levels. The weakening remnants of Tropical Cyclone
Nicole continues to lift northward as cold front slides east
tonight. Modified temperatures withe latest surface obs, their
trends and blended in the NBM this evening into tonight. Kept
pops fairly high for the next couple of hours, then advect drier
air into the region from the southwest. More changes later this
evening.
Previous discussion:
As of 240 PM EST Friday...
Rainbands from Nicole moving through...tornado threat mostly
over but areas of moderate to heavy rain continue through
tonight...
Large rain shield from TD Nicole was over much of WV/SW VA/NW
NC this afternoon. To the west drier air had worked in aloft and
skies were partly cloudy across the Piedmont. The Tornado Watch
has been allowed to expire as this area has been worked over.
Lightning has not been an issue in our area, but storms were
rotating today from time to time. At this time, the tornado
risk is not enough to keep the watch going.
CAMs show scattered convection continuing ahead of the surface
low/center of TD Nicole just to the west. Tonight rainfall
comes to an end for most between 9 PM and midnight as winds come
around to the SW/W and the 700mb low moves into PA/NY state.
Upslope showers continue for the western Blue Ridge mountains
through Saturday morning.
QPF totals have averaged 1-3" with higher amounts in Watauga and
Botetourt Counties. Totals through Saturday morning will be
closer to 2-4" with isolated 6+" amounts. A Flood Watch remains
in effect for the Grayson Highlands and surrounding Blue Ridge.
Winds will remain gusty but veer to the SW and diminish
somewhat tonight. Some of the higher peaks in the Wind Advisory
including the Grayson Highlands were gusting between 40-50 mph.
This advisory goes until 7 PM.
As of 250 AM EDT Friday...
Tornado Watch Issued for Piedmont.
First of three primary band of moderate to intense showers
crossing through Virginia early this morning. High-Res guidance
has the next crossing through northern North Carolina into
central Virginia roughly between 10Z/5AM and 18Z/1PM with the
core of remnant tropical system.
So most locations will have a more concentrated period of
showers lasting around 4 hours, a break with less coverage and
intensity, then the next band with another 3 to 4 hours of more
numerous showers with more intense rainfall.
Isolated thunderstorms, some with rotation, are possible in
either band, but development of more intense cells will depend
on heating and building some surface-based CAPE. Based on when
the SREF has a 500J/Kg CAPE that would put the highest potential
from 10AM to 6PM.
As the center of the system moves into northern Virginia wind
veer to the southwest then west but will remain gusty.
Precipitation end east of the Blue Ridge but fill in on the
western upslope areas of the central Appalachians.
Winds above the surface will peak around 45 to 60 knots out of
the southeast this morning. Wind gusts at the highest
elevations will be in the 40 to 50 mph range. Enhanced winds
will also be possible with the bands of showers coming through
but that shorter time scale will be handled with Special Weather
Statements or Severe Thunderstorm Warnings if needed.
Again expecting non-diurnal temperature trends today as dew
points rise into the 60s ahead of the tropical system. Staying
close to NBM guidance for lows tonight.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 245 AM EST Friday...
Trending colder with a scattered showers Saturday night...
As we progress into Saturday night, temperatures will start to
fall behind the trough axis, and residual moisture across the
mountains may change to or mix with snow showers, especially
across western Greenbrier County, WV. Across eastern areas, some
of the daytime rain showers may progress into parts of
southwest Virginia, mainly along and north of Route 460.
By Sunday, and through Monday night, colder high pressure will
settle over the region with temperatures five to ten degrees
below normal by the end of the period.
For Monday night, we will be watching for the potential of yet
another southern stream shortwave trough approaching the region.
Anticipate increasing clouds Monday night with small chance of
some light snow reaching the Northern Mountains of North
Carolina by daybreak Tuesday.
Confidence in the above weather scenario is moderate.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 235 PM EST Friday...
Mix of rain and snow in the mountains for Tuesday...
A chilly pattern for our area this time frame with a broad trough in
place. A southern stream wave will bring rain and some snow to the
area Tuesday into Tuesday night, mainly high elevation snow, then
lingering upslope rain/snow showers Wednesday.
Temperatures will play a factor in the precipitation type. For the
bulk of the day for most of the region the precipitation is expected
to be light rain. However, for the highest ridges and peaks light
snow or a mix of light rain and snow will be more probable during
the morning, and potentially into and through the afternoon. If the
system does arrive a little sooner currently suggested, more of the
area will still be at or below freezing at the onset of the
precipitation, and we could see a brief light mix of precipitation
across eastern sections around sunrise.
On Wednesday evening into Thursday, high pressure starts to build
in, lasting into early Friday. Another front approaches Friday but
at this time it is looking dry.
Temperatures should be below normal for most of this period
especially on the high temperatures.
Confidence in the above portion of the forecast is above average for
precip Tuesday but lower on rain vs snow. Forecast confidence is
above average also for mainly dry weather for mid to late week after
this system.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As of 632 PM EST Friday...
Periods of showers with IFR to MVFR ceilings continue through
tonight into Saturday morning. Areas of drizzle, stratus, and
some fog are expected overnight with plenty of low level
moisture still around. The mountains may see upslope showers
through 6Z or so. We should see MVFR becoming VFR by mid morning
Saturday with drier air working in.
SSE winds will remain gusty through tonight before turning more
SW and decreasing some after midnight. Generally expecting
winds 15-25 kts with higher gusts for the ridges of the southern
Blue Ridge through about 6Z.
Average confidence for ceilings, visibilities and winds.
Extended Aviation Discussion...
Expect MVFR conditions to return for the mountains Saturday
night into Sunday morning. Winds will also remain gusty this
weekend in the wake of the frontal passage with gusts 20 to 30
mph from the northwest.
Drier air and VFR conditions arrive during the day Sunday and
Monday.
Another system is likely to bring sub-VFR conditions and
precipitation for Tuesday and Tuesday night. Drier air arrives
for Wednesday.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/SH
NEAR TERM...KK/SH
SHORT TERM...SH
LONG TERM...DS/WP
AVIATION...KK/SH