Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/07/23
Area Forecast Discussion
National Weather Service Binghamton NY
644 PM EST Mon Mar 6 2023
.SYNOPSIS...
A clipper system will bring some accumulating snow overnight,
grazing parts of the Southern Tier of New York, but mostly
focused over northeastern Pennsylvania, where snow may be heavy
at times late tonight. Northwest flow will bring colder and
cloudier conditions to the region Tuesday, with widespread light
lake effect snow showers. This pattern will linger through most
of the week ahead.
&&
.NEAR TERM /THROUGH TUESDAY/...
634 PM update...
No significant changes made to the forecast at this time. The
onset of the steady snow that is expected to move in this
evening was delayed by about an hour as the very dry boundary
layer moistens up with the onset of precipitation. The axis of
heaviest snowfall was not changed, but the northern edge of the
snowfall gradient was sharpened up along and just north of the
NY/PA border. Also at this time, it appears the heaviest
snowfall rates will occur between 10 PM and 3 AM...where rates
could approach 1 to 1.5 inches per hour briefly. There is also a
narrow window late tonight and early Tue morning over portions
of central NY were clouds could scatter out for a couple hours,
which could lead to a period of rapid raditional cooling and
drop temperatures over the northern Catskills and southern Tug
Hill into the mid to upper teens. The rest of the forecast
remains on track.
315 PM Update...
Surface ridge axis extends across central NY and NE PA this
afternoon. This will cause a surface low presently over
Illinois to divert to the SE after reaching PA, but not before
producing a narrow band of snow that will graze the southern
portion of our CWA overnight.
Models have come into better agreement on the track of the
surface low and location of the heavier snow band. Precipitation
already falling in southern lower Michigan will spread east
into western NY/PA along and north of a band of low level
frontogenesis and a low level deformation zone. Southerly winds
at 850 mb look to briefly enhance late this evening over central
PA, likely keeping the highest snow totals just to the west of
our CWA.
Most models, including most HREF members and subsequent HRRR
runs, bring liquid QPF amounts of 0.50 to 0.75 inches into the
far SW corner of Steuben County NY, then across Luzerne County
PA, and quickly tapering off to less than 0.10 inches just to
the north (e.g., southern Susquehanna County). The northern
extent will be limited by a pronounced dry slot in the 900-800
mb layer. BUFKIT soundings show this holds together fairly well
overnight north of the PA line.
Temperatures in the Wyoming Valley have climbed up to the
mid-40s this afternoon, but dewpoints remain in the low to
mid-20s, and there`s the dry layer just aloft as well. This
should allow precip to start off as rain but quickly change over
to snow, though snow-to-liquid ratios look to stay around 7-8:1
over the area with highest QPF.
Bottom line, expect a narrow strip of 3 to 5 inches across
Luzerne County, with the lower amounts in the valley, and higher
amounts in the mountains on either side. A few isolated 6 inch
amounts are not out of the question, particularly in western
Luzerne County, but the bulk of the area, including the more
populated regions, should stay inside Advisory criteria. Another
consideration is the timing -- heaviest snowfall rates of 1 to 2
inches per hour will only last for an hour or two, and all the
snowfall will occur well after the evening commute, and several
hours before the morning commute, reducing impacts.
In the wake of this system, gusty NW winds will transport colder
air into the region, and begin setting up widespread light lake
effect clouds and snow showers. A shortwave trough dropping in
from the north will cause an uptick in snowfall rates Tuesday
night as 850 temps drop to -14 to -16C. Some areas may see 2 to
3 inches of snow from late Tuesday morning through late Tuesday
night, mainly around the eastern Finger Lakes.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
330 PM Forecast...
High pressure centered over central Canada will extend into the
eastern Great Lakes region, brining NW flow and a cold airmass to
the region. 850mb temps will warm up to -6C during the morning
hours. This is not an ideal temperature difference between Lake
Ontario and this surface, but bufkit soundings show enough low level
moisture to produce light snow showers. Scattered light lake effect
snow showers and flurries are expected to be present through the
period with the Finger Lakes having the best chance for continual
scattered showers. Temps on Wednesday will be in the mid 20s to low
30s across NY with mid 30s in NEPA. Thursday will see a slight
warming to temps in the low 30s to low 40s across the region.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
330 PM Forecast...
The main concern for this period will be the development of the next
winter system to impact the region Friday night into Saturday.
After a hodgepodge of model solutions for this system over the past
few days, guidance is starting to come together on the initial
development of this system over the midwest. A shortwave is modeled
to develop over the upper Midwest Friday morning and move to the
ESE. After this initial shortwave development, model solutions
diverge. Not as greatly as before but certain features develop
within the models that either allow the storm to impact our region
or send it south of the CWA. First is the location of the high
pressure system over central Canada, and how it moves with the
shortwave. Second is the strength of the shortwave and where the
surface low develops. The GFS develops a much stronger shortwave
earlier in the period with no high pressure blocking to the north.
This allows the surface low to deepen and move ENE into our CWA
starting Friday night and leaving on Saturday. The Euro is much
weaker with the shortwave and keeps a strong ridge north of the low
as it progresses eastward. This keeps the surface low much weaker
and pushes the system to the ESE as it enters the Great Lakes,
mostly missing the CWA to the south. The ensemble guidance for each
of these models generally match up with the deterministic solutions
so it at this point, it is hard to see which solution will be more
accurate. Both develop a secondary low off the NJ coast, which if
developed quickly and its eastward progression isn`t too fast, our
SE counties could get a secondary blast of snow Saturday afternoon.
For this forecast, the NBM was used as a starting point with PoPs
capped to chance after Saturday morning given the high variability
in the model solutions after this period. This gives us a mix of
rain and snow through the period.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
All sites are currently VFR. However, a narrow band of snow over
western NY and central PA is drifting east. While rain or mix will
be possible prior to 03z at AVP, snow is expected to begin around
03z. With it, visibilities will be reduced while snow is present
with restrictions falling into the LIFR category for a few hours.
Snow may linger through much of the early morning hours, but should
be over by sunrise. ELM may also get clipped by these snow showers
this evening. Confidence was lower that there will be restrictions
there, so a tempo group was added for a few hours. If this band of
snow drifts further east than expected, then BGM could also observed
snow showers, but confidence was too low to include snow in the TAFs.
Lake effect clouds will move in Tuesday morning, bringing MVFR
restrictions to all NY terminals, except ELM. These restrictions are
expected to last through the rest of the TAF period. Snow showers
are possible at SYR tomorrow evening. ITH and RME could also see a
brief snow shower, but confidence was too low to include at this
time. Visibilities may drop if a band is right over a terminal.
Winds are calm for now, but become gusty after 06z. North to
northwesterly winds will be as high as 15 to 20 kts with gusts of 25
to 30 kts, starting during the mid-morning hours and lasting through
the early evening hours.
Outlook...
Tuesday Night through Thursday...Restrictions possible with
lake effect snow showers; mainly Central NY sites.
Friday...Mainly VFR under high pressure.
Saturday...Restrictions possible with rain, snow, or both as a
coastal low may develop.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory until 7 AM EST Tuesday for PAZ038-043-
044-047.
NY...None.
&&
$$
SYNOPSIS...MPH
NEAR TERM...BJT/MPH
SHORT TERM...JTC
LONG TERM...JTC
AVIATION...BTL
Area Forecast Discussion
National Weather Service Boston/Norton MA
1011 PM EST Mon Mar 6 2023
.SYNOPSIS...
Dry and quiet weather tonight through early Tuesday as low
pressure tracks well south of our region. The dry/quiet trend
continues as we head mid to late in the week, but it will be blustery
at times. Could have some ocean effect rain/snow showers across
the Cape/Islands Wednesday and late Thursday. Temperatures will be
near seasonable. Lots of uncertainty for this coming weekend as
low pressure tracks near/south of New England. This could bring us
our next shot for wintry weather.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
1000 PM Update:
Forecast in general looks on track with dry weather but with an
increasing covg of mid to high clouds associated with a passing
weak frontal system through the northern mid-Atlc states. Only
the 18z GFS and the 00z FV3-WRF show any QPF into parts of
Hartford County but given air mass both at sfc but through 800
mb as well is quite dry, dry weather to prevail despite the
appearance on radar.
All that said, the challenge will be on low temps given the
increasing mid/high clouds, northerly mixed winds but also CAA
occurring on the same north winds. Temps were already several
degrees warmer than prior expectations and used a mix of the
bias-corrected RGEM and bias-corrected HRRR datasets into the
forecast to continue to slow cooling some through the balance of
the overnight. Winds will be a bit stronger across
eastern/northern areas, and less across western MA/western-
northern CT where the potential for some decoupling exists. Thus
warmer lows by a few degrees into the upper 20s to the mid 30s,
tending colder to the north and west.
Highlights...
* Gusts continue though gusts are diminishing.
* Dry with increasing clouds as a weak low pressure system tracks to
the southwest of southern New England.
Hope you were able to enjoy some of todays mild temperatures and the
abundant sunshine! Afternoon maximum temperatures topped out between
the upper-40s to the low-50s. Gusts this afternoon were generally
between 25 to 35 knots, those gusts do ease overnight. Guidance
remains in good agreement the surface ridge to our west breakdown
and the pressure gradient relaxes. Still there is good low level
mixing, should be able to mix up to 950mb, northwest gust between 15
and 25 knots are likely. As it is expecting to be gusty do not
expect a night of radiational cooling. Seasonable overnight lows are
expected in the middle and upper-20s.
Dry conditions continue tonight, guidance keeps the track of a weak
surface low southwest and impacting the NYC area. For our area, just
clouds and a LOW chance for a flurry across southwest Connecticut.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Highlights...
Tuesday...
Any morning sunshine will be short-lived, increasing clouds by mid-
morning as multiple shortwaves pivot around an area of low pressure
east of New England. PWATs are greatest from Cape Ann and south to
Cape Cod and Islands at 0.4 inch, could lead to isolated rain or
snow shower. Otherwise, the daylight hours are dry with an abundance
of cloud cover. Temperatures aloft are not much colder than it was
on Monday, but given the added clouds it will be noticeably
cooler as afternoon temperatures reach the upper-30s to low-40s.
Winds start to pick up again with a LLJ with winds 30 to 40
knots, leading to a gusty afternoon as NNW to N winds gust
between 20 and 30 knots.
Tuesday Night...
Dry with clouds. Southern New England is under a broad area of
cyclonic flow, north to northwest winds remain gusty too. This
pattern allows for a fairly seasonable night temperature wise, lows
fall into the low and middle 20s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Highlights
* Generally dry and quiet weather across the region through Fri with
near seasonable temps. May be a bit breezy at times on Wed/Thu.
* Lots of uncertainty for this coming weekend as there could be
impacts from a coastal system, but need to hone in on the exact
track.
Wednesday through Friday...
Caught in cyclonic flow through much of this period. A cutoff will
be rotating just to the east/northeast of Newfoundland through this
period, while a ridge builds into the Great Lakes. The ridge axis
moves into the eastern Great Lakes/New England by late Friday. Will
be caught between a high nudging in from northern Canada and a deep
low near Newfoundland through this period.
Generally anticipating dry and quiet weather through the vast
majority of this period across southern New England. The only
exception is across the Cape/Islands where there will be
opportunities for ocean effect rain/snow showers Wed and late Thu
into early Fri. Did have to blend the forecast toward the latest
GFS/ECMWF/GEM guidance as the NBM is not picking up on these precip
chances. At this point looks like any precip will be light.
Anticipate it will be a bit breezy through this timeframe due to the
tightened pressure gradient between the incoming high and low near
Newfoundland. Will have roughly 20-40 kts of northerly flow across
southern New England on Wed at 925 hPa. Should not be too difficult
to mix down as colder air advects in with 0 to -4 degree Celsius air
overhead. Expect a similar airmass in place through Fri, but winds
shift on Fri as the ridge axis builds in. Will see those gusty winds
coming down on Thu and especially Fri as the pressure gradient
relaxes with the high nudging in. Temps will be near seasonable with
highs generally in the 40s. Lows ranging from the mid 20s to mid 30s.
Saturday and Sunday...
Confidence in the forecast lowers significantly during this
timeframe. The ridge axis over our region breaks down or builds into
Nova Scotia/Newfoundland. In response to this a trough digs from the
Great Lakes into the Mid Atlantic/southern New England and offshore.
At this point given the differences in the upper dynamics am
uncertain on where a coastal low will track. This could potentially
bring us impactful winter weather this weekend.
Given the large spread amongst guidance have stuck with the NBM at
this point in time which paints chances of precipitation through the
weekend. Will note that both the EPS/GEPS guidance have trended
further to the south, similar to their deterministic models, which
would result in minimal if any impacts to southern New England. The
GEFS continues to trend near the benchmark, while its deterministic
guidance is further to the N/NW. If the GEFS is correct then there
would be more in the way of winter impacts to southern New England
through the weekend. On top of this thermal profiles are all over
the place as the track of the system will be key to determining
exact ptypes. There will be a blocking high in place, which could
keep colder air locked into our area. Need to see how things
continue to trend as the week progresses. If folks have travel plans
they will want to stay tuned to the forecast.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
00Z TAF Update
Tonight...High confidence.
VFR, dry, and NW winds 10 to 15 kts, gust to 20 to 30 kts.
Tuesday...High confidence.
VFR through the morning. Lowering cigs to MVFR through by early
afternoon across eastern Massachusetts. Dry day, though a low
chance for -RASN exists for the outer Cape. Wind remains gusty
from the NW/N up to 20 kts.
Tuesday Night...High confidence.
Dry with a mix of VFR/MVFR. Winds NW/N between 15 and 20 kts,
gusts to 30 kts.
KBOS Terminal...High confidence.
KBDL Terminal...High confidence.
Outlook /Wednesday through Saturday/...
Wednesday: Mainly VFR, with areas MVFR possible. Windy with
gusts up to 30 kt.
Wednesday Night through Thursday: Mainly VFR, with local MVFR
possible. Breezy.
Thursday Night through Friday: VFR. Breezy.
Friday Night: Mainly VFR, with local MVFR possible. Breezy.
Slight chance SN.
Saturday: MVFR/IFR conditions possible. Windy with gusts up to
35 kt. Chance RA, chance SN.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Tuesday Night...
A dry period tonight through Tuesday night, with a low
probability for a shower for the waters east of Cape Cod during
Tuesday afternoon. Winds and seas diminish this evening across
the waters, bringing an end to current Gale Warnings and Small
Craft Advisories for a brief period of time. Winds pick right
back up Tuesday, followed by increasing seas. Likely will need
to re-issue a Small Craft Advisory later today after current
headlines expire.
Outlook /Wednesday through Saturday/...
Wednesday: Strong winds with gusts up to 30 kt. Rough seas up
to 10 ft. Slight chance of rain showers.
Wednesday Night: Moderate risk for Small Craft Advisory winds
with gusts up to 25 kt. Areas of rough seas. Slight chance of
rain showers.
Thursday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of rough seas.
Thursday Night: Winds less than 25 kt. Areas of rough seas.
Slight chance of rain showers.
Friday: Winds less than 25 kt. Local rough seas.
Friday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. Slight chance of rain.
Saturday: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Seas up to 5 ft. Chance of rain.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 1 AM EST Tuesday for ANZ230>235-251-
256.
Small Craft Advisory until 7 AM EST Tuesday for ANZ250-254-255.
&&
$$
SYNOPSIS...BL/Gaucher/KP
NEAR TERM...Loconto/Gaucher
SHORT TERM...Gaucher
LONG TERM...BL
AVIATION...BL/Loconto/Gaucher/KP
MARINE...BL/Loconto/Gaucher
Area Forecast Discussion
National Weather Service State College PA
1104 PM EST Mon Mar 6 2023
.SYNOPSIS...
A strong but fast-moving low pressure area will zip directly
over the Laurel Highlands tonight as it speeds eastward. This
will lead to a heavy snowfall for the northern mountains this
evening and early tonight, and mainly rain for the southern
half of the state. High pressure builds in with a gusty wind
Tuesday. Expect generally fair weather into Friday with the next
mixed precipitation event slated to arrive Friday or Friday
night. It will turn blustery and colder for the weekend.
&&
.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
A fast-moving area of low pressure, located over southwest PA
at 03Z, will track just south of the forecast area late this
evening, then off of the Mid Atlantic coast early Tuesday
morning. Strong warm advection at the nose of a 40kt low level
jet, combined with a plume of +1 SD pwats, is producing an area
precipitation late this evening over eastern Ohio into northern
Pennsylvania, with a narrow band of heavy snow focused along a
ribbon of low and mid level fgen forcing from KDUJ to KIPT.
Current RAP guidance indicates that this area of enhanced
frontogenesis will slide east-southeast late this evening,
resulting in locally heavy snowfall over the N Mtns, roughly
between KBFD-KIPT.
Only minor changes have been made to the previous snow
forecast by incorporating latest HRRR qpf. Still expect a narrow
band of around 6 inches over the north central mountains, with
markedly lower amounts south of there and less than an inch
south of a KFIG-KUNV-KRDG line. SLR should generally be fairly
low with model profiles indicating plenty of riming in the lower
3km with temps in the -2C to -5C range. Expect precipitation to
taper off rapidly from west to east after 06Z, as shortwave and
associated surface low pass east of the state.
Will continue to maintain near 100 pct POPs overnight. However,
HREF reflectivity stamps indicate precipitation should fall
primarily in the form of rain showers over the southern
counties, with diminishing POPs toward the southern border.
Can`t even rule out a rumble of thunder over the Laurel
Highlands with the passage of mid level shortwave around 06Z.
A few upstream strikes have been noted and the latest RAP
indicate some minimal cape in this area.
&&
.SHORT TERM /7 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
A few lingering upslope snow showers over the Laurels around
dawn should give way to clearing skies, as strong subsidence
overspreads the region behind the departing shortwave Tuesday.
A fairly tight pressure gradient should result in gusty
northwest winds Tuesday. Bufkit soundings support gusts between
30-35kts by afternoon.
There appears to be an opportunity to beat NBM dewpoints
Tuesday afternoon, with northwest flow and very dry air above a
weak inversion signaling an afternoon dewpoint drop. The
MixedDewpoint tool and MAV guidance are way lower than NBM
dewpoints Tue afternoon, but have taken a conservative approach
to remain in collaboration with neighbors. Mixing down 850mb
temps of -5C to -8C yields expected highs from the low and mid
30s over the N tier, to the upper 40s across the Lower Susq
Valley.
A deep moisture on the western periphery of upper low off of the
east coast is progged to edge into northern PA Tuesday night,
supporting scattered orographic flurries/light snow showers,
perhaps producing a dusting in spots. Otherwise, expect fair and
continued blustery conditions.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Fair weather is expected for Wednesday into Thursday, as an
upper level ridge builds eastward into the area. Wednesday will
be a bit chillier than normal, with temperatures moderating to
near normal by Thursday afternoon.
For the end of the week, the focus will shift to a sharpening
upper level trough that is expected to dig from the Great Lakes
into the northern Mid Atlantic region and evolve into a cutoff
low. The associated surface low is progged to track to the west
of PA Friday into Fri night, drawing milder air overtop the
chilly air in place at the surface, before a secondary low
develops off the northern Mid Atlantic Coast. This points
towards a potential wintry mix late Friday or Friday night.
Odds favor chilly and unsettled conditions Saturday with
scattered rain/snow showers accompanying the passage of the
upper low. Generally fair and seasonable conditions look likely
Sunday, as upper low lifts out. By Monday both the GEFS and
ECENS show a deepening upper trough approaching from the Grt
Lks with an associated coastal low passing too far east to
affect central PA. The bulk of ensemble members point toward
only scattered rain/snow showers associated with the trough
passage Monday. However, a few indicate the associated coastal
low will come close enough to PA to produce a more significant
precip event.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
Low pressure will pass just S of KJST tonight, sliding along a
warm front stretched from KPIT-KLWX. A long-lived band of
(mainly) snow will cut thru the nrn mtns for 6-8hrs thru about
07Z. LIFR is expected at BFD and perhaps IPT later this evening
and early tonight as the precip gets heavier there. UNV will be
on the srn fringe of the moderate to heavy SN by around midnight.
JST and will be south of the heaviest precip and may be rain
for much of the night, but eventually gets cold enough for all
snow by the end of the night.
AOO will miss out on the bulk of the precip, getting some
around or just after midnight, but not dipping to IFR for more
than an hour or two. An hr or two of SN is poss at MDT and LNS,
but only very late tonight. It should all be over with before
sunrise, and probably around 08Z in UNV/AOO/IPT. The low
pressure goes east fast, and the falling pressure and incoming
high pressure will result in gusty WNW wind on Tuesday. Some
upslope SHSN are expected for the wrn highlands as a small
secondary wave drops across in the morning.
Outlook...
Wed...AM low cigs possible NW Mtns. VFR elsewhere.
Thu...VFR conditions.
Fri...IFR poss areawide in snow/mixed precip.
Sat...IFR/MVFR W in SHSN. MVFR/VFR elsewhere. Gusty wind.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 2 AM EST Tuesday for PAZ004-010.
Winter Storm Warning until 5 AM EST Tuesday for PAZ005-006-011-
012-041-042.
Winter Weather Advisory until 5 AM EST Tuesday for PAZ017>019-
037-045-046-049-051>053-058.
&&
$$
SYNOPSIS...Dangelo
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Fitzgerald/Evanego
AVIATION...Dangelo/Colbert
Area Forecast Discussion
National Weather Service Cheyenne WY
448 PM MST Mon Mar 6 2023
.SHORT TERM...(This evening through Wednesday night)
Issued at 300 PM MST Mon Mar 6 2023
Afternoon GOES-18 WV/VIS imagery showed a closed upper level low
nearly stationary off the WA/OR coast. A broad trough dominated
much of the Intermountain West with southwesterly flow aloft. An
inverted surface trough extended north-south along the WY/CO front
Range. Convergence along this trough has been the focus for snow
shower development, albeit more scattered and less intense compared
to Sunday. Most of the showers were oriented northeast-southwest
from Centennial to Wheatland. Snow accumulations were light with
visibilities as low as a few miles. East to southeast winds 10-15
kt with occasional gusts to 25 kt prevailed east of the trough, with
westerly 10-20 kt winds to the west. Temperatures were in the 30s.
Some lower ceilings persisted across the NE Panhandle.
Models/ensembles are in good agreement with the persistent southwest
flow throughout the short term. Periodic shortwaves and a stalled
surface boundary near the Laramie Range will be the primary focusing
mechanisms for snow shower development. The belt of strongest 250mb
winds (150kt) weakens and shifts east toward the Upper Midwest during
the next 12 to 24 hours. The upper low off the Pacific Northwest
coast moves onshore, transitioning to a trough Wednesday morning.
The trough tracks east across the Great Basin Wednesday afternoon
and the central Rockies and High Plains Wednesday night.
Scattered snow showers will continue tonight and Tuesday, tapering
off Tuesday night and Wednesday morning. Snow accumulations during
this time will Range from 1 to 3 inches over east-central WY, 3
to 5 inches over the Snowy/Sierra Madres, and less than an inch
elsewhere. There will be areas of late night/early morning fog along
the I-80 Cheyenne to Sidney corridor, with patchy fog elsewhere.
As the main trough ejects east across WY/CO Wednesday night, snow
showers will become more numerous with large scale lift in the left
front quadrant of a 125kt 250mb jet. Moderate snow accumulations
are expected with the more persistent showers. Increased PoPs to
60-80 percent Wednesday night. Winds begin to increase Wednesday
as the low level pressure gradient tightens in response to the
approaching trough.
Temperatures throughout the forecast period will average 10-15
degrees below normal. Expect daytime highs in the 20s and 30s with
nighttime lows in the teens and 20s.
.LONG TERM...(Thursday through Monday)
Issued at 300 PM MST Mon Mar 6 2023
Active weather continues into the long term period, but impacts look
to remain fairly low at this time. We will be watching for strong
winds behind the system on Thursday, and another shortwave to plow
through this weekend that may bring renewed mountain snow and strong
winds.
Models have coalesced around a weaker and faster scenario for the
system Wednesday night into Thursday. An upper level shortwave will
eject east by Thursday morning, with tight northwest flow wrapping
in behind it as ridging tries to build in. Trended faster in the end
of snowfall Thursday morning compared to prior forecasts, with
appreciable snow after daybreak mostly confined to the mountains,
and areas northeast of a Douglas to Sidney line. Gradients tighten
in the wake of this upper level low, so expecting northwest winds to
increase across the area Thursday morning. The probability for high
wind criteria being reached has been increasing, and is highest for
the Arlington/Elk Mountain area and the I-80 summit, though fairly
widespread windy conditions are likely across the high plains. While
we should see the clouds breaking and clearing out for many areas
Thursday, it will remain chilly with 700-mb temperatures around -12C
to -14C behind this system.
Warm air advection finally returns Thursday night into Friday as the
axis of a dirty ridge becomes established over the Rockies. Even as
warmer air pushes in aloft, Friday morning may be the coldest of the
week with a window of less cloudiness possible, contingent on the
winds easing at the surface. Guidance has been trending warmer for
Friday owing to the faster exit of the previous upper level low.
GEFS mean 700-mb temperatures climb to around -5C by midday Friday,
which should support temperatures climbing some 5 to 10F over
Thursday`s highs, with the greatest differences west of the Laramie
Range. Flow aloft turns more west to WSW Friday into Saturday so
we could see another round of strong winds developing Friday night
into Saturday. There will also be a fair amount of moisture in
the flow, so snow showers may return to the mountains and possibly
lower elevations west of the Laramie Range Friday afternoon and Friday
night. If current expectations hold, advisories would likely be needed
for this period in the mountains, with potential impacts extending
to the I-80 corridor west of Laramie. Uncertainty is still quite high
considering the lead time. Height/pressure gradients will also be
increasing again during this time period, so will need to watch for
another round of strong winds for the wind prone areas mainly Friday
through Saturday.
The ridge axis is expected to pass through our area around the early
Saturday timeframe. Ensembles have come into much better agreement
supporting this longwave ridging moving through, with all GEFS
members now showing 700-mb temperatures climbing above freezing by
12z Saturday. The main source of uncertainty in the weekend forecast
will be another shortwave passing to our north. This progressive
system is expected to be well north, but carry a cold front to the
south, while it flattens the ridge and lead to more zonal flow
aloft. If the timing is able to hold off until Saturday night, we
should manage a very warm day over the high plains. The NBM 75th
percentile even pushes KCYS over 60 degrees (would be the first
instance of 2023). However, an earlier frontal passage would likely
cut 15+ degrees off those numbers. For the official forecast,
blended towards MOS and NBM 50th percentile guidance, but will need
to watch this frontal passage timing. Lift will be limited with this
system outside of the favorable orographics in the mountains, so not
expecting widespread precipitation, but we may see some scattered
rain/snow showers sometime Saturday afternoon/Saturday night with
the frontal passage. Forecast uncertainty increasing considerably
for Sunday and beyond. Some ensemble members drop temperatures
fairly significantly behind this shortwave, while others have a
modest drop and quick rebound. Thus, went with the middle of the
road guidance, with most likely scenario resulting in near normal
temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 445 PM MST Mon Mar 6 2023
Confidence growing on a widespread IFR/LIFR event developing later
this evening for airports east of I-25. Generally used latest HRRR
guidance for onset of conditions at each airport. There is low
stratus fairly widespread across Nebraska that will be pulled in
this evening with easterly upslope flow. Conditions may continue
through Tuesday morning before lifting after 18Z.
&&
.FIRE WEATHER...
Issued at 300 PM MST Mon Mar 6 2023
Fire weather concerns will be low as a cold and unsettled weather
pattern dominates the districts. Several low pressure disturbances
in the southwesterly flow aloft will produce periods of light to
moderate snow through Thursday. Winds will increase by the end of
the week with stronger winds possible for portions of southeast
Wyoming. Warmer temperatures are forecast Friday and Saturday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MAJ
LONG TERM...MN
AVIATION...GCC
FIRE WEATHER...MAJ
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
947 PM EST Mon Mar 6 2023
.UPDATE...
The accumulating snow scenario for tonight is progressing on schedule
upstream over northern Lower MI and is set to spread into SE MI with
a peak from about 10 PM to 4 AM. It is a fast moving system while
bringing a pattern of snow showers with sufficient intensity for a
quick 1 to 2 inch accumulation before ending and exiting eastward by
6 AM. This is followed by a drop in temperatures into the mid and
upper 20s which could enhance potential for icy roads by sunrise.
Mid evening satellite and radar composites illustrate an elevated
convective response to forcing associated with the strong mid level
circulation and within a corridor of steep mid level lapse rate.
Hourly mesoanalysis measured 700-500 mb lapse rate near 8 C/km in
this initial area of snow shower expansion. RAP forecasts then
project this corridor of elevated instability to progress across the
Tri Cities and Thumb region after midnight. Consensus of hi-res
models show a concentration of higher intensity snow showers occuring
on the south flank of the instability axis where increasingly
sheared DCVA focuses vertical motion along/NE of the inverted surface
trough. This is where the going forecast positions the snow
accumulation axis which begins in the 1 to 2 inch range in the Tri
Cities and tapers off as coverage and intensity fade to the south and
east.
The primary forecast element to highlight is surface temperature
trends. Readings are expected to fall into the mid and upper 20s
after the snow ends and as clouds clear quickly from north to south
through sunrise. This could result in icing of any wet road surfaces
or solidifying snow cover as the morning travel period gets
underway. Partly to mostly sunny sky is then expected to lift
temperatures quickly above freezing toward noon.
&&
.PREV DISCUSSION...
Issued at 713 PM EST Mon Mar 6 2023
AVIATION...
A band of mixed rain/snow/pellets that was over the DTW corridor
followed the primary low pressure system eastward and out of SE MI
to start the forecast. It leaves behind a break in precipitation
activity but still a wide range of flight conditions ranging from
VFR below 5000 ft at MBS to residual IFR ceiling at DTW. Further
evolution begins later this evening as the trailing northern Great
Lakes wave moves into southern Lower MI. This system brings mainly
snow to the terminal corridor beginning first at MBS and spreading
southward toward DTW during the late night. Upstream observations
show some virga preceding a more active pattern of snow crossing
Lake Michigan and in northern Lower MI. Sub 1 mile LIFR visibility
is reported from several locations from eastern WI toward the
Straits in support of an inch or two of accumulation in SE MI when
it arrives. The good news is this system passes through the area
rapidly during the late night followed by an equally rapid decrease
in clouds. Most locations will be clear to scattered by sunrise
followed by a modest rebound in coverage as daytime heating gains
traction during the morning. VFR below 5000 ft could become briefly
broken before mixing scattered again during the afternoon and
clearing into Tuesday evening.
For DTW... Residual IFR ceiling recovers into low end MVFR before
the next round of snow moves in from the north. A brief shot of IFR
visibility brushes the terminal with less than 1 inch of
accumulation before the snow quickly ends. Decreasing clouds is then
expected into the morning.
DTW THRESHOLD PROBABILITIES...
* High for cigs aob 5000 feet tonight. Low Tuesday.
* High confidence for all snow overnight.
PREV DISCUSSION...
Issued at 314 PM EST Mon Mar 6 2023
DISCUSSION...
Zonal 150 knot upper level jet will anchor a compact mid level wave
now featured over central Wisconsin across lower Michigan tonight.
Intersection of favorable upper jet forcing with the resident mid
level frontal boundary and steep mid level lapse rates the impetus
for a solid, mesoscale fgen response over southern sections lower
Michigan at press time. This activity will continue to offer bouts
of heavier convective showers, with the strongest bursts capable of
generating sleet and/or briefly flipping precipitation type to snow
despite temperatures generally hovering in the upper 30s to lower
40s. This ascent will vacate to the east this evening, just as an
uptick in height falls arrive from the northwest. Renewed increase
in large scale ascent tonight as dcva again engages the frontal zone
and effectively drags the convergence southeastward with time. This
process will effectively initiate weak cold air advection, in turn
supporting a precipitation type as mainly snow showers as coverage
increases from northwest to southeast. There remains a convective
element to this activity, so brief higher intensity rates plausible.
Forecast will highlight the potential for 1 to 2 inches of
accumulation north of M-59 (highest Saginaw Valley), with less than
an inch to the south. A rapid downturn in coverage expected 08z-09z.
Seasonable and generally benign early March conditions set for the
mid-week period. Steady early day dry air advection under prevailing
low level northeast flow should effectively eliminate lingering
stratus, affording a high degree of insolation Tuesday. This works
to offset a slightly cooler resident thermal profile - highs
arriving near average of mid 30s to lower 40s. Ridge of high
pressure anchored north of lake Superior then maintains influence
under a building upper height field Wed and Thu. Retention of a low
level easterly gradient mutes the potential for a more meaningful
warming trend, even trending lakeshore communities cooler given the
onshore flow. No precipitation forecast through Thursday.
Attention by the end of the week focused on behavior of a deeper
vort maximum forecast to arrive on the west coast Wednesday before
ejecting east or northeast during the late week period. Perusal of
the collective ensemble/deterministic model solution space and
associated cluster analysis highlight the typical points of
uncertainty in terms of defining potential magnitude, amplitude and
resulting trajectory of the governing wave. General trend toward a
less amplitude mean trough and corresponding northward positioning
of the main height fall center as the wave ejects across and out of
the rockies, but still with potential for some deepening upon
arrival locally Friday and Friday night pending favorable upper jet
interaction. Standard implications to the thermal profile and
subsequent projection of possible precipitation type trends. Several
inches of snow accumulation certainly in play should a deeper, less
progressive and colder outcome emerge.
MARINE...
Light mixed precipitation is ongoing across the local waters this
afternoon with rain favored to the south transitioning to snow
showers with northward extent. Transition to snow occurs this
evening across all waters as colder air temperatures filter in,
though precipitation departs well before daybreak Tuesday. Gusts
continue to hold aob 30 knots while locked into easterly flow,
backing to the north-northwest by daytime Tuesday on the backside of
the cyclonic circulation. Transient low level wind field combined
with a relatively shallow mixed layer keeps similar wind pattern
through mid-week with gusts aob 30 knots. Primary focus is onshore
flow elevating wave heights in the mainly ice-free nearshore zones,
with Small Craft Advisories in effect through mid-week as a result.
Looking ahead to next weekend another potential winter storm brings
chances for widespread heavy precipitation and wind gusts possibly
to gale force.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 4 AM EST Wednesday for LHZ421-441>443.
Lake St Clair...None.
Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EST this evening for LEZ444.
&&
$$
UPDATE.......BT
AVIATION.....BT
DISCUSSION...MR
MARINE.......MV
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Grand Rapids MI
1026 PM EST Mon Mar 6 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 1026 PM EST Mon Mar 6 2023
Forecast is on track this evening. A shortwave can be seen diving
off to the southeast over Lake Michigan per water vapor imagery.
Regional radar loops show a fair amount of precipitation ahead of
the wave over Central Lower Michigan. Precipitation type via
observations is primarily snow, but there is some rain mixed in as
well. The precipitation will continue off to the southeast tonight
and exit the forecast area by roughly 400am. A mixture of rain and
snow is expected based on temperatures near to slightly above
freezing. Some light snow accumulations of an inch or two are
possible in the far northeast CWA up towards Reed City and Clare.
Clearing will take place late tonight, sweeping from north to
south in the wake of the mid level shortwave.
&&
.DISCUSSION...(This evening through next Monday)
Issued at 331 PM EST Mon Mar 6 2023
-- Rain and snow tonight --
Rain and occasional lightning in southern Michigan associated with
warm advection and isentropic ascent just below 700 mb amid weak
static stability will move out the area by nightfall. A batch of
precipitation in its wake will then develop over west-central Lower
Michigan and move southeast. This is as the 850 mb low and 700-500
mb trough, now located over Wisconsin this afternoon, moves through
late this evening. Similar to last night, it will be a rain changing
to wet snow scenario especially in a zone between Ludington, Grand
Rapids, and Jackson, as air temperatures in the upper 30s this
evening cool toward the wet bulb temperatures, which will be just a
couple degrees above 32 at the surface and at 32 degrees no higher
than 1000 feet aloft. Precipitation should end a few hours prior to
the morning commute.
QPF in the 12Z HREF and NBM between 0.1 and 0.3 inches centered
around Mt Pleasant / Alma would suggest a dense or slushy inch or
two, given snow/liquid ratios that will be 10:1 or less. Recent runs
of the HRRR have focused the heaviest band of precip even a bit
farther south/southwest, into the warmer air and precip-type
transition zone. Limited or briefly minor impacts to road
conditions are expected, so will shy away from an advisory at this
time.
-- Uneventful midweek --
High pressure / ridging extending from central Canada through the
Great Lakes into the Southeast US will keep the weather on the
quieter side Tuesday to Thursday. The sunniest day will likely be
Tuesday, with mid- to high-altitude clouds increasing thereafter. A
light breeze from the northeast/east is expected. Temperatures will
be pretty close to normal for this time of year.
-- Potential snow Friday --
The sharp south-to-north temperature gradient across the CONUS will
tend to relax in the medium range. By consequence the strong quasi-
zonal upper level jet will gradually weaken and fragment into
northern and southern streams late in the week. However, an upper-
level shortwave / +PV anomaly ejecting from the trough anchored
over the west coast on Wednesday will likely undergo baroclinic
development in the Midwest on Thu-Fri. Accumulating snow is
possible late Thu night through Fri. The ECMWF and Canadian
ensembles produce lesser precip amounts than many of the GEFS
members, with an advisory-level event being the most likely
outcome.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 744 PM EST Mon Mar 6 2023
A weather disturbance will move southeast through the area from
this evening into the overnight hours (between 00z and 09z). A
mixture of rain and snow is expected as it moves through.
Visibilities will dip into the MVFR category at times. Ceilings
will lower into the IFR category tonight with widespread IFR
expected in place by 04z. Late tonight and into Tuesday morning
(between 09z and 13z), conditions will improve to VFR once again.
VFR weather is then expected for most of Tuesday as high pressure
builds into the region. Northeast to north winds are expected the
next 24 hours at 5 to 15 knots with gusts to around 20 knots at
times.
&&
.MARINE...
Issued at 331 PM EST Mon Mar 6 2023
Winds from the northeast may become hazardous to small craft late
tonight as high pressure noses in on the backside of the weak low
moving through the southern Great Lakes. Hazardous waves are
expected to build beyond 5 nautical miles from shore but may
peel toward the shore near South Haven by Tuesday morning. After
that for the next few days, winds should be a bit more relaxed from
the northeast or east.
&&
.HYDROLOGY...
Issued at 331 PM EST Mon Mar 6 2023
The flood watch for the Maple River near Maple Rapids continues
for now, though concern for flooding later this week is trending
lower. River levels will remain on the high side (not abnormal
for spring snowmelt season) after 3 rounds of heavy precipitation
over the past two weeks. A few days break with near-normal
temperatures should allow rivers time to remain at manageable
levels. Slow snowmelt in the Grand and Kalamazoo basins may push
river levels a bit higher from where they are now.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 8 AM EST Tuesday for LMZ844>849.
&&
$$
UPDATE...Duke
DISCUSSION...CAS
AVIATION...Duke
HYDROLOGY...CAS
MARINE...CAS
Area Forecast Discussion
National Weather Service North Platte NE
535 PM CST Mon Mar 6 2023
...AVIATION UPDATE...
.SYNOPSIS...
Issued at 340 PM CST Mon Mar 6 2023
Attention continues to focus on a significant winter weather
event for the northern Plains which could track south through
northern Nebraska Thursday. Today`s model runs of the GFS, NAM, SREF
and Canadian show improvements in timing and track.
Key messages:
-The blended forecast strategy suggests 6-7 inches of across ncntl
Nebraska during the 24 hour period ending midnight Thursday.
-The ECM and GFS ensemble mean solutions are still too divergent
in both location and snowfall amounts to lend moderate to high
confidence. They appear to be converging however. The ECM favors
SD, MN and IA for the best snowfall while the GFS straddles the
NE-SD border into IA.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 340 PM CST Mon Mar 6 2023
An upper level disturbance across northwest WY this afternoon will
track northeast into MT tonight and then east into ND Tuesday. The
srn fringe of a deformation zone associated with the disturbance
will brush northwest Nebraska tonight and Tuesday morning. The
latest model blended solution, which is close to the HREF and the
NAMnest, has shifted snowfall amounts north, perhaps as much as 50
miles. The blended forecast suggests less than an inch of snow along
and north of highway 20 tonight affecting areas mainly west of
Valentine.
Light snow is also possible across the Panhandle and other parts of
western and north central Nebraska Tuesday with accumulations of a
dusting possible. The mechanisms for this snow is modest isentropic
lift on the 280-285K surface and upslope wind. This weather type
will need to be monitored as there is a split in the models with the
RAP suggesting freezing drizzle but the GFS, NAMnest and NAM12
suggesting snow. Temperatures at the saturated h850mb to 800mb layer
are -4C to -8C.
Low-end chance and slight chance POPs continue place Tuesday night
across most of wrn and ncntl Nebraska for what appears to be light
snow. This forecast is guarded by the GFS, NAM and NAMnest
predicting snow while the RAP continues to suggest the potential for
freezing drizzle.
.LONG TERM...(Wednesday through Monday)
Issued at 340 PM CST Mon Mar 6 2023
Attention continues to focus on a significant winter weather
event for the northern Plains which could track south through
northern Nebraska Thursday. Today`s model runs of the GFS, NAM, SREF
and Canadian show improvements in timing and track. The models are
in agreement a closed h700mb should be located across far northeast
Nebraska Thursday evening-00z. The models show a h700mb low tracking
across nrn Nebraska, near or south of the SD border during the day
Thursday.
The ECM continues to show the disturbance tracking north of the
Black Hills and then southeast toward MN and IA Thursday. This storm
track, supported by it`s ensemble mean, would negate winter storm
conditions across northern Nebraska. It is worth noting the ECM has
chirped up on the prospect of strong WAA driven snow Thursday but
the liquid amounts, around 1/3 of an inch, are 1/3 to 1/2 of the
stronger operational GFS. Most of the snow from this event will fall
from the combination of strong WAA, isentropic lift and
convective enhancement.
The blended forecast strategy suggests 6-7 inches of across ncntl
Nebraska during the 24 hour period ending midnight Thursday. WPC`s
day-4 experimental Winter Storm Outlook indicates two counties
across ncntl Nebraska eligible for a Watch. No weather highlights
will be issued with this forecast. The ECM and GFS ensemble mean
solutions are too divergent in both location and amounts. They
appear to be converging however. The ECM favors SD, MN and IA while
the GFS straddles the NE-SD border into IA.
A check on winds shows the best opportunity for strong winds will be
Thursday afternoon across southwest Nebraska where the models show a
deep mixed layer forming. Sustained winds near 25 mph may develop.
Across ncntl Nebraska, these winds would occur Thursday night, but
they will be subject to decoupling lessening speeds somewhat.
One other weather system may affect wrn and ncntl Nebraska this
weekend. The GFS, GEM and ECM are in good agreement carrying the
remainder of the over-sized upper low near the coast of the Pacific
Northwest east across srn Canada and then southeast through upper
midwest. This system should reinforce the cold air in place across
the region. A modest warm up is possible Saturday ahead of the
system. The ECM and GEM models suggest high temperatures around 50.
The stronger GFS suggests 30s to near 40. The blended forecast is in
the middle for highs in the 30s and 40s. Regardless of the outcome,
the models show colder air from cntl Canada funneling in behind
this system. Highs in the 30s and 40s are in place for next Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 535 PM CST Mon Mar 6 2023
Low ceilings are the primary aviation weather concern for western
and north central Nebraska terminals through Tuesday evening. The
low stratus deck will likely remain in place, resulting in MVFR to
IFR conditions. Additionally, snow showers may pass through the
northern terminals (KVTN) overnight and again tomorrow. Northeast
winds transition to southeast throughout the period, but stay
generally near 12 kts.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CDC
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Snively
Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
923 PM EST Mon Mar 6 2023
...New UPDATE...
.UPDATE...
Issued at 913 PM EST Mon Mar 6 2023
Arrival time of incoming front still looks to be around 6-9am
tomorrow morning. Tightening pressure gradients ahead of the front
will counteract nocturnal inversion a bit and keep winds elevated
slightly overnight. Will be a dry FROPA tomorrow morning, with
only a wind shift noted. Only adjustment to the forecast overnight
was to adjust dewpoints a tad. Blended the 23z HRRR and NBM 10th
percentile through midnight, then trended mostly towards the NBM
10th percentile for the remainder of the overnight hours. Not a
significant adjustment - the NBM mean was just running a degree
or two too warm.
&&
.SHORT TERM...
(This evening through Tuesday)
Issued at 246 PM EST Mon Mar 6 2023
Key Messages:
1. Weak front sweeps through overnight, leading to slightly cooler
Tuesday.
Discussion:
Our stout morning inversion took a little longer than expected to
break, but it finally has done so this afternoon and now breezy
winds are flowing across the valley. A weak low over the Great Lakes
is advecting 25-30 knots of southwesterly 850 mb flow. This combined
with the breaking of our morning inversion has allowed for these
winds to mix down as gusts. Temperatures outside are 70s valley
wide, the warmest of this week. Tuesday morning a cold front will
pass through switching our winds to the northwest, bringing slightly
cooler weather for Tuesday. Not a lot of moisture available to this
front, especially with the delayed return of southerly flow today.
Guidance is similarly pessimistic on shower potential, so kept it
out of the forecast, but could see an isolated light shower make it
through the dry air in some of the higher elevations. Rest of the
day on Tuesday will be clearing skies under northwest flow, with
slightly cooler but still quite pleasant temperatures.
&&
.LONG TERM...
(Tuesday night through next Monday)
Issued at 246 PM EST Mon Mar 6 2023
Key Messages:
1. Colder temperatures are expected through this period, with highs
generally near to below normal. Some frost will be possible Tue
night and Wed night in northern sections.
2. Two main periods of rain chances - Thu/Thu night/Fri, and Sun/Sun
night.
Discussion:
Colder air will be building into the area at the start of the
period. Lows on Tuesday night will drop into the 30s for most of the
area, and frost will be a possibility in SW VA and NE TN Wednesday
morning. The uncertainty with this potential lies with winds, as the
models maintain a pressure gradient across the area as the high over
the Great Lakes builds south. Wednesday night looks similar, but
with the added uncertainty of increasing cloud cover.
Rain chances spread into the area with increasing isentropic lift on
Thursday as low pressure tracks across the central Plains and the
high pressure ridge moves to the Atlantic coast. Low level dry air
will likely result in some virga initially, with rain chances
increasing from south to north Thursday afternoon as low levels
moisten under stronger lift. Peak forcing and QPF comes Thursday
night, followed by the cold front passage Friday morning. Expect
about a half inch to one inch QPF area wide this period. Cold
midlevel temperatures under the closed low may keep scattered to
isolated showers in northern sections into Saturday, with some
higher elevations potentially seeing some snow.
The next system will follow quickly behind and affect the area on
Sunday. Model agreement and run-to-run consistency are poor this
period, so confidence on details is low, and PoPs will remain in the
chance range as a result. The flow aloft is nearly zonal and not
well amplified, so this does not appear to be a highly impactful
system. A question with this system is whether temperatures will
support snow or rain, which will depend on the track of the low.
&&
.AVIATION...
(00Z TAFS)
Issued at 618 PM EST Mon Mar 6 2023
Winds will likely stay elevated through much of the night (though
likely not gusty) as pressure gradients tighten across the region
in advance of approaching front. FROPA is expected in the 12z-14z
time frame, and should be dry with only some SCT-BKN bases
between 4-6k ft AGL as the front passes through. Mixing should be
sufficiently deep enough tomorrow to expect some gusts into the
mid teens perhaps at all sites. Had highest confidence at KTRI so
only included gusts there.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 55 74 41 59 / 0 0 0 20
Knoxville McGhee Tyson Airport, TN 52 67 37 57 / 0 0 0 10
Oak Ridge, TN 51 66 36 56 / 0 0 0 10
Tri Cities Airport, TN 50 61 29 54 / 0 0 0 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...CD
LONG TERM....DGS
AVIATION...CD
Area Forecast Discussion
National Weather Service Norman OK
418 PM CST Mon Mar 6 2023
...New AVIATION...
.SHORT TERM...
(This evening through Tuesday)
Issued at 254 PM CST Mon Mar 6 2023
An initial cold front made it a little further south today than
anticipated yesterday, with the pre-frontal trough located across
south central OK instead of central OK. Here, temperatures have
climbed into the low 80s as expected. The cold front will surge a
little further south overnight before stalling near the Red River
around sunrise. Meanwhile, aloft, a subtle mid level shortwave
trough is expected to traverse NM Tuesday morning and move across
northern OK throughout the day Tuesday, while isentropic ascent
increases near the same area. Elevated showers, with perhaps brief
thunder, will accompany these two lifting mechanisms across northern
OK. Further south, near the surface front, some isolated surface
based moist convection could initiate but forcing will be weaker
there. A conditional threat of marginally severe hail appears
possible during the afternoon and evening south of I-40.
Considerable cloud cover and the aforementioned rain chances have
increased our confidence to lower afternoon high temperatures
behind the front tomorrow considering it`s current location.
However, even in the short term there is still disagreement on the
position of the surface front tomorrow (the HRRR suggests ~72 F at
21Z tomorrow while the NAM nest is ~42!)
&&
.LONG TERM...
(Tuesday night through next Sunday)
Issued at 254 PM CST Mon Mar 6 2023
Higher rain chances are expected to develop later overnight
Tuesday as deeper isentropic ascent commences. There`s still some
uncertainty on the placement of the main core of precipitation
near the ~925 mb front late Tuesday but the general consensus is
along and just south of the I-44 corridor. Some heavy rainfall
will be possible into early Wednesday morning, with anomalous
PWATs and training showers/storms possible. In addition to heavy
rainfall, there could be some marginally severe hail considering
just enough deep layer shear and elevated instability, but lapse
rates should limit the overall threat. The highest chances for
severe weather should be limited to the southern half of OK and
portions of north TX where more buoyancy is present.
The first main round of precipitation should exit our forecast
area eastward late Wednesday morning. However, redevelopment
appears likely by early Wednesday evening as a subtle PV anomaly
lifts northeastward out of West TX and a LLJ intensifies. The
axis of heaviest rainfall will again depend on where the frontal
boundary and near surface baroclinic zones are. There is still
much uncertainty regarding QPF. Wednesday night into early
Thursday morning may have the best potential for both marginally
severe storms and localized flooding. A flood watch may be
considered by the overnight shift, if confidence increases in the
areas of heaviest rainfall. This may be mainly for ESE OK where
soils remain moist from recent rainfall and training could
continue within persistent WSW mid level flow.
Forecast confidence decreases even more late in the week through
the weekend. During the day Thursday, a mid to upper level
shortwave trough is expected to move out of the central Rockies
and into the central plains, with an accompanying cold front
perhaps entering far northwest OK. Rain chances should still be
ongoing across our southern and southeastern zones, as a warm
front lifts northward there. Overall, it appears rain chances
should end late Thursday as the cold front surges southward
across the Red River with a much drier airmass behind it.
&&
.AVIATION...
(00Z TAFS)
Issued at 354 PM CST Mon Mar 6 2023
Northeast to east winds will persist through Tuesday. MVFR
ceilings are expected to form at most TAF sites after daybreak
Tuesday. Scattered rain showers are expected in north central
Oklahoma before noon and will likely increase and develop more
widely by late afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 47 56 44 55 / 0 20 70 60
Hobart OK 45 55 43 55 / 0 20 60 30
Wichita Falls TX 53 70 49 60 / 0 20 60 60
Gage OK 37 45 37 52 / 0 10 20 10
Ponca City OK 39 48 43 53 / 0 50 50 60
Durant OK 56 75 57 68 / 0 20 70 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...03
LONG TERM....03
AVIATION...09