Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/25/22
Area Forecast Discussion
National Weather Service Bismarck ND
639 PM CST Thu Feb 24 2022
.UPDATE...
Issued at 638 PM CST Thu Feb 24 2022
Quiet and cold weather continues. Only change needed was to
adjust cloud cover a bit to address some clouds moving in from the
west.
&&
.SHORT TERM...(This evening through Friday)
Issued at 244 PM CST Thu Feb 24 2022
Wind chills and clouds highlight the short term forecast period.
Currently, high pressure is situated over northwest Minnesota with a
southerly return flow situated over most of western and central
North Dakota. Mostly sunny skies were noted across most of the
forecast area. The exception is the far south central into southeast
ND where mid and high clouds were noted along the northern periphery
of a Central Plains system. Temperatures were in the single digits
above zero (most) or below zero (a few).
For tonight, the main forecast issue is the potential for lower
stratus to return northward within the southerly flow behind the
exiting Arctic High. The HRRR, and especially the RAP are indicating
lower stratus lifting northward into southwest and south central ND,
with the RAP lifting into all the way to the Canadian border by late
tonight. Given that RAP doesn`t have a good handle on what`s going
on now, we`re discounting this, but there are indications of higher
cloud cover southwest and south central form the raw model guidance
and some MOS guidance. The amount of clouds, or lack of clouds will
also have impacts on our overnight low temperatures and wind chills.
Currently, forecast lows are from 5 to 15 below with a steady
southerly surface flow. Once again we will need wind chill
highlights to the north and east of the Missouri River. Later shifts
may need to extend west of the River, but with uncertainty in sky
cover and mostly marginal wind chills, chose to leave counties along
but west of the river, out of the advisory.
Warmer on Friday, especially west of the Missouri with temperatures
rising into the 20s. Mainly teens north and east of the river, with
some upper single digits holding on over the far eastern portion of
the forecast area.
.LONG TERM...(Friday night through Thursday)
Issued at 244 PM CST Thu Feb 24 2022
The extended forecast is highlighted by warmer temperatures and a
mostly dry forecast.
Current guidance shows a continued steady rise in both low and high
temperatures Friday night and Saturday with little spread in NBM
ensemble temperature guidance yielding high confidence in forecast
temperatures. Highs climb into the 20s north and east, to the 30s
southwest on Saturday. It does look like we will be breezy to
windy Saturday with some patchy blowing snow possible, especially
in open country, in areas that had recent snow.
Beyond Saturday there is a quick increase in spread in NBM
ensemble temperature guidance and low confidence in the position
of the upper ridge to our west and strength/timing of any waves
that move through the northwest upper flow pattern over the
Northern Plains. It does look to remain dry for the most part
through Saturday. Thereafter, we would expect mostly small
precipitation chances as individual waves track through upper
level flow. This is depicted in our given guidance beginning
Sunday night and continuing through midweek. Therefore, no
changes to our given pops/temperature guidance beyond Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 638 PM CST Thu Feb 24 2022
VFR conditions are expected to prevail through the forecast
period.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory until 11 AM CST Friday for NDZ001>005-
009>013-021>023-025-035>037-046>048-050-051.
&&
$$
UPDATE...JJS
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...JJS
Area Forecast Discussion
National Weather Service Boston/Norton MA
947 PM EST Thu Feb 24 2022
.SYNOPSIS...
A Winter Storm will bring significant snowfall to much of the
region late tonight and Friday, along with a period of mixed
precipitation for a time along and south of the MA Turnpike.
Mainly dry weather weather with colder than normal temperatures
is in store for most of the upcoming weekend into much of next
week.
&&
.NEAR TERM /THROUGH FRIDAY/...
945 PM Update...
Previous forecast is on track and no changes are planned after a
quick look at the early 00z guidance. Snow should rapidly
overspread the region between 1 and 4 am from southwest to
northeast. It will quickly become moderate to heavy with very
strong 850 mb frontogenesis and a negative EPV signature as
well. The biggest uncertainty remains the timing/northward
extent of the 750 to 800 mb layer warm nose. Nonetheless...most
locations south of the MA Turnpike should see a good front end
thump of heavy snow before the changeover Friday morning.
Perhaps the biggest uncertainty is along the immediate south
coast, Cape/Islands whether they have a few hours of moderate to
heavy snow or end up mainly sleet followed by rain.
===================================================================
Highlights
* Snow overspreading region from SW to NE roughly between 12-4
AM. Snowfall rates will pick up very quickly as a band moves
in. Should see 1-2" per hr snowfall rates into & through the
Fri AM commute.
* Widespread 8-12" of snow north of the MA Turnpike into Friday
evening, but biggest impacts are still anticipated Friday AM.
Could have some localized 12+ inches along the MA/VT/NH
border.
* Still some uncertainty in exact totals right along & south of
the MA Turnpike as precip changes over to sleet along with a
plain rain across SE MA. Should see a big total gradient from
north to south with around 8" for northern areas & 1-3" along
the immediate coastline.
* Should still see a Flash Freeze Fri afternoon/early evening
along/SE of the BOS-PVD corridor as cold air surges in.
Trough lifts from the Mid Mississippi River Valley into the
central/eastern Great Lakes by Friday morning. The trough
continues lifting northeastward into northern New England by
Friday night. Low pressure lifts up the TN/OH Valley tonight
into the eastern Great Lakes. A secondary low develops south of
the south coast early on Friday and lifts offshore by late
Friday.
Forecast has not changed a whole lot from the previous shift as
it looked pretty good. The main change in this package was to
upgrade to Winter Storm Warnings from northern CT east through
northern RI into portions of SE MA. From southern RI eastward
have gone with Winter Weather Advisories.
Still have similar concerns forecast wise as the previous shift
and yesterday. Main issue is the warm nose pushing in from south
to north toward daybreak in the 700-850 hPa layer. Pretty good
consensus amongst guidance in where this pushes in at this point
in time. There are some subtle differences where the 925-700 hPa
max temp 0 degree line is. Still roughly getting to around the
MA Turnpike. The NAM still pushes things a bit further north,
which given we are within the 24 hr window think it is
reasonable. This line demarcates roughly where there will be
wintry mix concerns will be. Initially will be starting off as
all snow and become heavy quickly. Will see the mixed ptype
transitioning from south to north around daybreak into the early
afternoon, latest HREF depicts this very well. Will see any
mixed ptypes or plain rain transitioning to all snow as things
are winding down late on Friday/Friday eve as colder air punches
in. Again the NAM is still a bit faster than other guidance,
which if right would result in a slightly faster transition and
further north which would eat away at the snowfall totals a bit.
Still something we will need to keep a close eye on for future
updates.
Despite the warm nose could see this offset a bit by the heavy
banded precipitation expected. Have strong wind convergence
along/south of the south coast during the morning into the early
afternoon within the 850 and 925 hPa layer. On top of this there
is a a solid frontogenetical band at 850 hPa traversing in late
tonight through Friday morning from SW to NE per most guidance.
Leaned on the HREF guidance as the snowfall rates of 1" per hr
really highlights the risk well. There could potentially be
rates of up to 2" per hour, but may be difficult given there is
around 10-15 units of omega within dendritic growth region. Per
the RAP guidance there may be a higher risk of those heavier
rates right along the MA/NH border where we`ve got some 20+
units of omega within the DGZ. Regardless, this will coincide
heading into and going through the Friday AM commute. Expect
travel to be very difficult for a large portion of the region,
but especially where Winter Storm Warnings are hoisted.
Given the colder air locked in place across southern New England
due to the strong high building over Quebec. Once the surface
low lifts offshore will see the colder air surging
southeastward. Given this quick surge of colder air am
anticipating a Flash Freeze later on Friday into Friday night.
Think this risk is highlighted greatest at this point in time
where we have Winter Weather Advisories, but there may be a few
spots just a bit further to the N, like PVD where they may also
run into this issue as there may be a period of plain rain.
Given any wet pavement the flash freeze will result in icy
travel on any untreated roads. Folks will want to exercise
caution if traveling.
Temperatures on Friday will top out in the 20s across the higher
terrain and 30s elsewhere.
&&
.SHORT TERM /FRIDAY NIGHT/...
Highlights...
* Lingering light snow during the evening tapering off as low
pressure lifts offshore. Still have some convergence across
eastern areas during the evening, so may linger until late
Friday.
* Much colder air moves in with fairly widespread lows in the
single digits.
Still a bit of directional convergence across eastern areas and
snow will be fluffy given the colder air filtering in as the
low lifts offshore. Temperatures at 925 hPa drop to roughly -10
to -15 degrees Celsius. Think there could be perhaps an
additional inch or two across eastern spots before the snow
completely ends. Will have gusty winds during the evening with
the flash freeze risk in any wet spots that are untreated.
Low temps bottoming out in the single digits across the interior
and the teens to 20s along the coastal plain.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Highlights...
* Colder than normal pattern this weekend into much of next week
* Coldest air likely Sun night into Monday with reinforcing surge
possible Wed/Thu
* Other than chance of scattered snow showers Sun & Wed/Thu, dry
weather prevails
Details...
Saturday and Sunday:
High pressure moves in behind the departing low that will produce
accumulating snow across southern New England on Friday. While skies
will be bright, temperatures will struggle to climb above freezing
as a cold airmass overspreads southern New England. 925mb
temperatures remain between -7 and -10C through much of the weekend,
supporting high temperatures in the upper 20s and low 30s across the
area.
Light northwesterly flow and clear skies will promote radiational
cooling on Saturday evening. Low temperatures will fall back into
low to mid 10s across much of the area; Cape Cod will remain the
exception as gusty winds will prohibit decoupling.
Sunday afternoon and evening brings the chance for few snow
showers/flurries as a weak clipper system passes just north of our
area. Accumulating snow looks unlikely at this time, as temperatures
will moderate above freezing in many places due to cloud cover and
southwesterly flow much of the day.
Monday through Thursday:
Anomolously cold air works its way into the region behind the
departing clipper Sunday night through Tuesday morning. This is in
response to a piece of the polar vortex breaking off, and moving
across southeast Canada. 925mb temperatures dip to between
-15 and -22C region wide supporting temperatures in the upper 10s
and low 20s during the day on Monday. Should these values be
achieved, we would be in record breaking territory, with current
record low daily maximum temperatures sitting at 19F in Boston and
Worcester.
Seasonably cold temperatures will stick around much of the week.
There is a shot for sub zero low temperatures in western MA almost
every morning next week. High temperatures are unlikely to eclipse
40F in the next 7 days, save for the outer Cape and Islands.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
00Z update...no changes to previous TAFs, with dry weather this
evening, then snow arriving after midnight across western MA/CT,
then into RI and eastern MA during the predawn hours. Heaviest
snow/IFR-LIFR between 09z-13z across CT/RI and southeast MA, but
until 16/17z across northern MA. Changeover from snow to a
wintry mix 13/14z across CT/RI and southeast MA. Likely
remaining all snow Mass Pike northward. Snow totals for selected
terminals -
KBOS: 8-10"
KPVD: 4-6"
KBDL: 6-8"
KORH: 8-10"
Earlier discussion below.
========================================================================
Tonight...High confidence.
VFR to start, but conditions deteriorating rapidly to MVFR/VLIFR
from SW to NE around 06-09Z as snow overspreads the region. Will
have a wintry mix of snow/sleet and perhaps a touch of freezing
rain along the south coast toward daybreak and snow elsewhere.
A classic front end thump with snow quickly becoming heavy
roughly 1-2 hours after onset. Snow heavy in the 08-12Z range
where 1" or greater per hour snowfall rates are possible
along/north of the MA Pike. With this band of heavier snowfall
is the risk of LIFR/VLIFR conditions, which have tried to hone
in on in the latest update. Leaned toward the latest HREF/RAP to
zone in on the timing. E winds increasing to around 10 kts by
daybreak. Could have some 15-20 kt gusts along the immediate
coastline toward daybreak.
Friday...High confidence in trends, moderate in specific timing.
IFR to VLIFR conditions across southern New England with snow
across much of interior MA. Band of heavy snow with 1-2" per
hour rates possible will continue lifting northeastward across
the region during the morning into the early afternoon. Mixed
precipitation of snow/sleet and perhaps some freezing rain for
the south coast. As warmer air nudges into the region will see
that wintry mix push further north along and just north of the
MA Pike by mid/late morning. Will see portions of the south
coast transition to a plain rain, most likely across the
Cape/Islands. Will have a surge of colder air push in during the
afternoon as the system lifts offshore, which will gradually
transition any mix/rain over to all snow during the
afternoon/early evening. Could see some impossible improvement
to MVFR by late afternoon as precip becomes lighter. E winds
shifting to the NE/N at 10-15 kts with gusts of 20-30 kts late
in the day.
Friday night...High confidence.
MVFR with perhaps some IFR to start. Lingering light snowfall
tapering off from west to east. Could still have some snow
across the Cape/Islands due to Ocean effect. N/NW winds at 5-10
kts with gusts of 15-25 kts diminishing as the night progresses.
BOS TAF...High confidence in TAF.
BDL TAF...High confidence in TAF.
Outlook /Saturday through Tuesday/...
Saturday: VFR.
Saturday Night: VFR. Breezy.
Sunday through Sunday Night: VFR. Windy with local gusts up to
30 kt.
Monday: VFR. Breezy.
Monday Night: VFR.
Tuesday: VFR. Breezy. Slight chance SN.
&&
.MARINE...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Have hoisted a Small Craft Advisory for all waters late tonight
through Friday due to increasing seas/winds as low pressure
lifts in. Could perhaps have some occasional gale force gusts
across the outer waters Friday afternoon.
Tonight and Friday...High Confidence. Winds/Seas will generally
remain below small craft advisory thresholds this evening. However,
low pressure developing across our southern waters late tonight into
Friday will increase the pressure gradient. E to NE wind gusts of 30
knots should develop across most of our waters by daybreak Friday
and continue through the day. It is possible we see a few gusts up
to 35 knots, but winds will mainly in the high end small craft
advisory levels. Rough seas will develop with good ENE fetch.
New marine headlines will be needed once the current ones this
morning expire. Snow and mixed precipitation will also reduce
vsbys for mariners.
Friday night...High confidence.
Winds initially out of the N/NNE shifting to the northwest and
diminish as low pressure lifts offshore. Initially 15-25 kts
with gusts of 25-30 kts diminishing to 10-15 kts with gusts of
15-20 kts late. Seas falling to 4-7 ft by daybreak.
Outlook /Saturday through Tuesday/...
Saturday: Winds less than 25 kt. Seas up to 5 ft. Local
visibility 1 to 3 nm.
Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.
Sunday: Strong winds with gusts up to 30 kt. Areas of rough
seas.
Sunday Night: Strong winds with gusts up to 30 kt. Rough seas
up to 9 ft. Chance of freezing spray.
Monday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas. Chance of freezing spray.
Monday Night: Winds less than 25 kt. Local rough seas.
Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Slight chance of rain.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Storm Warning until midnight EST Friday night for
CTZ002>004.
MA...Winter Storm Warning until midnight EST Friday night for
MAZ002>019-026.
Winter Weather Advisory until midnight EST Friday night for
MAZ020>022.
RI...Winter Storm Warning until midnight EST Friday night for
RIZ001-002.
Winter Weather Advisory until midnight EST Friday night for
RIZ003>007.
MARINE...Small Craft Advisory from 4 AM to 10 PM EST Friday for
ANZ231>234.
Small Craft Advisory from 7 AM to 10 PM EST Friday for ANZ230.
Small Craft Advisory from 4 AM to 1 PM EST Friday for ANZ236.
Small Craft Advisory from 4 AM Friday to 4 AM EST Saturday for
ANZ235-237.
Small Craft Advisory from 4 AM Friday to 7 AM EST Saturday for
ANZ250-251-254>256.
&&
$$
SYNOPSIS...Nocera/BL/KS
NEAR TERM...Frank/BL
SHORT TERM...BL
LONG TERM...Nocera/KS
AVIATION...Nocera/BL/KS
MARINE...Nocera/BL/KS
Area Forecast Discussion
National Weather Service New York NY
1010 PM EST Thu Feb 24 2022
.SYNOPSIS...
High pressure over New England tonight gives way to low
pressure passing through late tonight into Friday. High
pressure returns Friday night into Saturday. A cold front will
pass through Sunday evening, followed by high pressure late
Sunday night through Monday night. An Alberta clipper low will
pass to the north on Tuesday, with another cold frontal passage
Tuesday night. Another clipper low may pass to the north
Wednesday night or Thursday morning.
&&
.NEAR TERM /THROUGH FRIDAY/...
Winter Weather Advisories remain in effect for all but far
eastern sections of Long Island.
There were some light radar returns moving across portions of
the area out ahead of a more organized area of precipitation
across the Mid Atlantic that will move in after midnight. Latest
HRRR simulated reflectivity shows weak returns generally
passing to the south and east of LI/NYC metro next couple of
hours. Only minor adjustments were made to the forecast at this
time. Biggest challenge overnight will be how quickly the
precipitation type transitions to rain along the coast and a
wintry mix inland. Guidance is in better agreement, but their
are still enough differences in the magnitude and timing of the
warm nose aloft and surface temperatures to impact snowfall
accumulation and ice accretion.
Precipitation develops from southwest to northeast across the
region late this evening into the early morning hours. Strong
warm advection in the middle levels may be briefly offset by wet
bulb cooling and precipitation dynamics. Thus, there is still a
possibility of a quick burst of snow at the coast, especially
the CT coast. However, the snow will be short-lived and may
quickly mix with or change completely to sleet shortly after
precip onset due to warm air aloft. An increasing easterly flow
will then help boost surface temperatures above freezing around
day break. This will effectively bring a change to plain rain
across Long Island and southern portions of the NYC metro. There
could be a brief period of freezing rain, specifically for the
NYC metro and NW Long Island around day break which could bring
a light glaze of ice.
Away from the immediate coast, there will likely be a few more
hours of snow, possibly moderate to locally heavy at times.
Interior NE NJ, the Lower Hudson Valley, and interior SW CT will
lie just on the colder side of the thermal gradient initially,
which briefly enhances frontogenesis. Snowfall rates of around 1
inch per hour are possible here early Friday morning through
around day break.
The middle level low track of this system is not favorable for
precipitation to remain all snow across the interior. The track
of the low well to the north and west of the area will allow
the warm advection aloft to bring temperatures between 850 mb
and 700 mb above freezing. This will change the snow to sleet
initially as the low level cold air looks dense enough. However,
easterly flow will warm the low levels bringing a change to
freezing rain and potentially rain before ending around midday.
Locations along the CT coast and southern Lower Hudson Valley
will see a bit more snow/sleet than closer to NYC metro and
Long Island, but the warming both aloft and at the surface will
bring a transition to freezing rain and then plain rain shortly
after day break.
By mid morning, saturation aloft diminishes and the precip intensity
likely drops off. Most locations should see liquid precip with the
highest chance of freezing rain across the interior.
Total snow/sleet accumulations have been adjusted downward given
the continued warming trend. These amounts may need to be
adjusted downward further, especially if the transition to
sleet is quicker. 2 to 5 inches of snow/sleet is expected across
the interior, highest along and north of I-84, dropping to less
than an inch for much of NYC and Long Island.
Total ice accretion amounts remain similar overall with a glaze
to a tenth across the NYC metro, SW CT, NW LI, to one to two
tenths further inland.
Brunt of precip falls during the morning hours with mainly dry
conditions in the afternoon. Highs should reach the middle and
upper 30s, to around 40 at the coast. Winds are not a concern
with the system, but could gust to around 20-25 mph near the
coast in the morning. Winds will pick up behind the system late
Friday, gusting 25-30 mph by evening. No precip is expected for
the Friday evening commute.
&&
.SHORT TERM /FRIDAY NIGHT/...
Breezy and cold conditions are expected Friday night as high
pressure starts to build into the area. The pressure gradient
looks steepest during the first half of the night, with winds
weakening early Saturday morning. Mostly clear skies are
forecast with just a few high clouds streaming across within the
SW flow aloft. Lows should range from the teens inland to the
low 20s near the coast. Wind chills early Saturday may be in the
single digits north to low teens south.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Zonal flow aloft this weekend will transition to a colder NW
flow early next week as a closed low traverses eastern Canada,
and a an upper ridge builds over western NoAm. This will send a
cold front through Sunday evening, followed by strong Canadian
high pressure early next week, then a series of weak clipper
lows followed by reinforcing shots of cold air.
Below normal temps expected for nearly the entire period, especially
on Saturday and Monday with highs only from the upper 20s to mid 30s
both days. Temps ahead of each of these passing fronts/clippers will
briefly moderate to a few degrees below normal on Sunday, Tuesday,
and Wednesday, with highs each of those days in the lower/mid 40s.
Still below normal on Thu with highs only on the upper 30s/lower
40s.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Strong high pressure over the Northeast will gradually give way
to low pressure approaching form the SW tonight. The low then
passes through on Friday before moving away late in the day.
VFR this evening, then rapidly lowering ceilings as snow and
sleet overspreads the area from the southwest mainly after 05Z.
Flight categories will lower quickly from VFR to IFR about 1 to
2 hours after the onset of the precipitation. A few spots may
even go LIFR for a time, especially the Lower Hudson Valley
terminals where moderate to heavy snow will fall before changing
over to a wintry mix. Coastal location are forecast to become
all rain from 10Z to 14Z.
The most challenging aspect of this forecast is the precipitation
type timing transition, which will likely change due to the
complexity of timing the warm air aloft and some differences in
the guidance.
Expected Runway accumulations:
KEWR,KLGA,KJFK,KISP - Around 1 inch
KTEB - 1-2 inches
KBDR,KGON - 2-3 inches
KSWF - 3-5 inches
NE winds veer to the ENE/E tonight, and more or less remain ENE
Friday morning. Winds will then become W/NW in the afternoon
with the potential for gusts 20-30kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments will likely be needed after 03Z for flight category
changes and precipitation type and then tomorrow afternoon for
the wind shift to the W/NW and improvement to VFR.
.OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
.Friday Night...VFR with NW winds G20-30kt the first half of
the night.
.Saturday...VFR.
.Sunday...VFR. SW G20-30kt becoming NW behind a cold front.
.Monday...VFR. NW G20-25kt possible.
.Tuesday...Mainly VFR. SW winds.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Sub-SCA conditions continue this evening, but will become SCA
levels late tonight into Friday as low pressure impacts the
waters. Gusts around 25 kt are expected in the morning on all
waters. There may be a brief lull early in the afternoon before
the pressure gradient increases again late in the day as the low
departs. SCA conditions are likely to persist through Friday
night on the ocean, with the non-ocean waters seeing winds
weaken in the evening. Ocean seas should build to around 5 to 6
ft late tonight into Friday morning, then slowly fall below 5 ft
late Friday night.
Any lingering 5-ft seas on the outer ocean waters should subside
early Sat morning.
SCA cond likely on the ocean and far ern Sound late Sat night, then
on all waters daytime Sat, and back to the ocean and the ern
Sound/bays Sunday night into Monday morning, both before and
after a cold frontal passage. W flow on Sunday could gust close
to 35 kt on the ocean while ocean seas peak at 5-10 ft, highest
east where wind fetch will be longest.
Minimal SCA cond, with 5-ft seas on the outer ocean waters, may
also be possible Tue night in SW flow ahead of an approaching
weak clipper low.
&&
.HYDROLOGY...
No hydrologic impacts are expected through the middle of next
week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 3 PM EST Friday for CTZ005>012.
NY...Winter Weather Advisory until 1 PM EST Friday for NYZ067>071.
Winter Weather Advisory until 10 AM EST Friday for NYZ072>075-
078-176>178.
NJ...Winter Weather Advisory until 1 PM EST Friday for NJZ002-004-
006-103>108.
MARINE...Small Craft Advisory from 4 AM to 11 PM EST Friday for ANZ338-
345.
Small Craft Advisory from 4 AM to 6 PM EST Friday for ANZ331-
332-335-340.
Small Craft Advisory from 4 AM Friday to 6 AM EST Saturday for
ANZ350-353-355.
&&
$$
SYNOPSIS...BG/DS
NEAR TERM...JC/DS/DW
SHORT TERM...DS
LONG TERM...BG
AVIATION...DW
MARINE...BG/DS
HYDROLOGY...BG/DS
Area Forecast Discussion
National Weather Service Blacksburg VA
1019 PM EST Thu Feb 24 2022
.SYNOPSIS...
Coverage of rainfall will diminish this evening as a wave of low
pressure exits to the east. A cold front will pass east across
the Appalachians during Friday morning, with high pressure and
cooler air building in behind the front that will bring
temperatures closer to normal for late February. Another low
pressure system will skirt close to our area Saturday, followed
by cold high pressure to start the new workweek.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1015 PM EST Thursday...
Dense Fog Advisory is in effect.
Visibilities are deteriorating across the forecast area as
combination of rain saturated air and lowering cloud base
results in areas of dense fog. Expectation is for fog to persist
until the arrival of a cold front Friday morning. The HRRR seems
to be doing a good job with respect to the low vsby forecast,
depicting the lowest visibilities near the Blue Ridge between
now and daybreak...spreading into the piedmont as the night
progresses and persisting there a bit longer due to the late
arrival of the front for areas east. There may also be some rime
icing and freezing fog near the Blue Ridge Parkway, Bent
Mountain, Apple Orchard Mountain where easterly upslope cooling
may suppress the surface temperature to near 30 degrees F. For
these locations expect icing on elevated objects.
The heaviest rain Thursday fell across the western New River
Valley and into the Holston and Clinch Rivers on the Tennessee
Valley side of the Appalachians. Stream levels in these area
will continue to run high through the overnight. Low water
crossings will be compromised until then. Other than some
drizzle, little or no additional rain is expected until the
front arrives Friday morning.
Latest wave of low pressure and warm front aloft have moved
north of the local region, radar indicating widespread
precipitation from Ohio across northern WV/VA and into PA/MD.
For our forecast area there may be some lingering drizzle, but
anything measurable will be limited until the arrival of a cold
front Friday morning.
Temperatures overnight will change very little along and east of
the Blue Ridge...hovering in the 30s. West of the Blue Ridge,
temperatures may steadily rise overnight as southwest winds
draw warm air northeast from the Tennessee Valley. Temperatures
west of the Blue Ridge which are in the 30s now, may rise into
the 40s by daybreak. West of the Appalachian Divide,
temperatures may remain in the 50s through the overnight.
Toward dawn, the cold front to our west will get a push from
passing low pressure, and begin advancing across the mountains.
We can expect a brief southwesterly wind shift ahead of the
front that will allow for modest improvement in the fog and low
ceilings, followed by a west-northwesterly wind shift as the
cold front passes. Shower activity with the cold front will be
confined mainly to the mountains during Friday morning, which
will then diminish by noontime as dry air arrives.
With skies clearing from east to west during the afternoon as
high pressure builds in, we can expect a wide gradient in
afternoon high temperatures, ranging from the mid 40s across
portions of southeast West Virginia, to the mid 60s across the
Piedmont of North Carolina. Will also see wind gusts ranging
from 20 to 25 mph across the Piedmont, to as high as 35 mph at
times across the mountains.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 135 PM EST Thursday...
Trends in the models are favoring mainly dry weather this
period, though the GFS/ECMWF continue to skirt shield of precip
as far north as the VA/NC border Saturday early Sunday, with
differences in timing.
For now will go with a blend of what we had in there with the
GFS/Euro which puts very low chances (less than 20%) into the
NC mtns/foothills late Saturday afternoon, then ramping up to
chance pops 30-50 south of the VA/NC border Sat night cutting
sharply to dry weather north of U.S. Highway 58 in Virginia. At
the moment, temp profiles favor mainly rain, with some higher
elevation snow, but overall, no more than a dusting at the
moment looks reasonable across places like Beech Mountain, NC.
This system skirts east by Sunday afternoon with clearing
skies. High pressure works in from the northwest Monday.
Temperatures this period run close to normal.
Forecast confidence is average on how far north precip makes it
and above average on temperatures/winds.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 1138 AM EST Thursday...
Weather Stays Quiet This Period.
Broad trough with northwest flow to set up this period, with
mainly dry weather, though some models hinting at just some rain
or snow showers midweek in the mountains. Odd model out is the
Canadian showing southern moisture overspreading the Carolinas
into portions of Virginia Wednesday into Wednesday night.
GFS/Euro and ensembles more agreeing on northwest dominant flow
to keep any southern stream moisture suppressed.
Temperatures this period should run at or just above normal,
but some differences in how much cold air follows the system
Thursday.
Forecast confidence is above average on limited threat of
precip/weather and average on temperatures.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
As of 1000 PM EST Thursday...
Dense Fog Advisory for areas along and east of the Blue Ridge.
This will impact KBCB/KROA/KLYH/KDAN with potential for
visibilities under 1/2SM.
Expectation through the overnight is for widespread IFR/LIFR
conditions due to stratus and fog. Exception will be areas west
of the Appalachian...from KBLF to TRI where MVFR conditions
will exist.
Shortly before dawn on Friday morning, rain chances will again
increase across the mountains as a cold front advances in from
the west. Can expect winds to shift southwesterly ahead of the
front around sunrise, which will allow for gradually improving
conditions, before the actual cold front passes across the lower
Mid-Atlantic during late morning, resulting in a westerly
downslope wind shift with gusts increasing to 25kt across the
mountains, and 20kt across the Piedmont. Mountain shower
activity will diminish quickly through late morning, making for
mostly dry conditions going into the afternoon.
Skies will gradually clear east of the mountains during the
afternoon as downslope winds persist. KBLF may see MVFR or
lower stratus hang on longer...models hinting at lingering
moisture along the western slopes through daybreak Saturday.
Extended Aviation Discussion...
VFR conditions are expected areawide Saturday.
A southern stream system may bring sub-VFR cigs to KDAN
Saturday night, but confidence in this is not high. Expect VFR
Sunday and Monday as high pressure settles in.
Forecast confidence is moderate this period.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Dense Fog Advisory until 8 AM EST Friday for VAZ010>020-
022>024.
Dense Fog Advisory until 10 AM EST Friday for VAZ032>035-
043>047-058-059.
NC...Dense Fog Advisory until 8 AM EST Friday for NCZ001-002-018.
Dense Fog Advisory until 10 AM EST Friday for NCZ003>006-019-
020.
WV...None.
&&
$$
SYNOPSIS...NF
NEAR TERM...NF/PM
SHORT TERM...KK
LONG TERM...KK
AVIATION...NF/PM