Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/15/23
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1108 PM EDT Tue Mar 14 2023
.SYNOPSIS...
Scattered snow showers and flurries will continue
overnight as low pressure slowly moves east of the Gulf of Maine.
The western facing slopes of the Taconics, Berkshires and southern
Greens will continue to experience snow showers overnight. Northerly
winds will remain gusty overnight with reduced visibility and
blowing snow in areas where snow is not heavy or wet. Additional
power outages remain possible through overnight due to the strong
winds and weight of snow on tree limbs, especially in the higher
terrain areas. Gusty winds continue into Wednesday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
...Winter Storm Warnings remain up to 8 am WED....
The latest RAP continues to show a vertically stacked deep low
pressure system around 983 hPa east of the Gulf of Maine. Bands
of upper deformation zone snow showers and flurries continue
some orographic enhancement off the Taconics and western New
England higher terrain. Some adjustments were made to PoP trends
based on the KENX radar and the latest 3-km HRRR and NAM.
Additional snow accumulations of 1-3" are possible over the
southern Greens, north-central Taconics and Berkshires.
Elsewhere expect a dusting to an inch possible. The Albany
International Airport is up to 10.1" as of 10 pm. Some hefty
snow amounts have occurred over the higher terrain with some
amounts in the southwest Adirondacks, southern Greens,
Berkshires, and eastern Catskills in the 30-36" range. Please
see our latest Public Information Statement with a full list of
reports. Thank you to all the spotters for the reports.
PREV DISCUSSION [0755]...The latest RAP has a 986 hPA low
northeast of Cape Cod near the Gulf of Maine. The h500
circulation will capture the low as it becomes vertically
stacked. Mid and upper level deformation snowfall continues
continues across eastern NY into western New England. Localized
Mohawk Hudson Convergence documented in the CSTAR research yield
some intense snowbanding in the Capital Region with snowfall
rates 1-2"/hr. The moderate snow continues across portions of
the Capital Region into the Taconics, southern VT and the
Berkshires. We adjusted the PoPs based on the radar trends and
expanded a bit south of the Capital Region and slightly to north
and west with lighter snow. We also updated the winds N/NW
10-20 mph with gusts 25-40 mph and added some blowing snow over
the Taconics, southern Greens, and Berkshires. We should see a
transition to upslope snowfall over the north- central taconics,
southern Greens and Berkshires with additional snowfall amounts
of 2-6". Thank you for all the snow reports. So far, a few high
amounts from our latest PNS include: 31.0" Windsor, Berkshire
Co., 36.0" 4 SW Palenville in Greene Co. in the eastern
Catskills, 32.0" Indian Lake in the southwest Adirodnacks, and
32.4" 2NNE Marlboro in the southern Greens.
.PREV DISCUSSION [0409]...Our coastal low has intensified to
985hPa, per the latest RAP analysis, as it slowly tracks towards
the Gulf of Maine. The most impressive pivoting band has
pummeled the southern Adirondacks, Mohawk Valley and parts of
the northern and eastern Catskills most of the day resulting in
12 to 20 inches in these areas. Outside of this pivoting band
and other snow bandlets, the snowfall rates have been weaker
with less efficient snow accumulations due to marginal
temperatures and smaller snowflakes. In fact, in the Hudson
Valley area, additional daytime snow accumulations have been
under an inch as the wet snow compacted or even partial melted
and new snow struggled to accumulate.
Now that the coastal low has pushed slightly north and westward,
its inverted trough has shifted southward towards Long Island
as seen on the RAP analysis. This has redirected the pivoting
band away from the southern Adirondacks and into parts of the
Hudson Valley including the Capital District. Forecast soundings
show the strong forcing within this band intersecting the
dendritic snow growth zone resulting in 1 inch per hour snowfall
rates so areas that have missed on much additional daytime
accumulations will experience periods of moderate to even heavy
snow the rest of this afternoon and into tonight. This includes
the Hudson Valley, the Taconics and parts of the western New
England. An additional 1 to 3 inches of snow is possible from
this band, especially as we lose daytime heating and the
effects of the March sun angle. With northerly winds funneling
down the Hudson Valley and winds shift northwest in the Mohawk
Valley, some Mohawk Hudson Convergence (MHC) would enhance
snowfall rates this evening.
By 00 - 03 UTC, the pivoting band should finally weaken and
diminish as our coastal low weaken and slowly exits out to sea.
However, strong northwest winds continuing in its wake will
maintain upslope snow showers in the western facing slopes of
the Taconics, southern Greens and Berkshires resulting in
further snow accumulations overnight. An additional 4 to 8
inches of snow is possible in these areas with snowfall rates in
excess of one inch per hour from the pivoting band and upslope
snow overnight.
Latest snowfall reports range from 5 to 10 inches with locally
higher amounts up to 12 - 24 inches in the eastern Catskills,
southern Adirondacks, southern Greens, and the Berkshires where
upslope effects and the impressive pivoting band resulted in
hefty snowfall rates. The highest amounts ranging 25 to 30
inches buried parts of Hamilton and Berkshire County as well as
the southern Greens. A big thank you to all the trained
spotters, CoCoRaHS, Cooperative Weather and social media
followers for sending us snow reports all day. Your efforts are
much appreciated. Some zones may short of Winter Storm Warning
criteria, namely southern Litchfield County, but due to
additional snow expected through tonight, we did not downgrade
any zones.
SLRs have been impressively low with this event as snowfall
amounts occurred from 1.00 - 1.50 inches of liquid equivalent.
This equates to 5 - 7:1 snow to liquid ratios. In the higher
terrain where the monster snowfall totals have occurred, SLRs
have been closer to climatology. Heading into this evening as
colder air wraps around the storm, the thermal profiles should
finally modify leading to SLRs closer to climo for more of the
region.
Besides the snow, northerly winds will remain strong this
afternoon and tonight with gusts ranging 30 - 40mph. As snow
turns lighter/fluffier, the increased winds will only further
reduce visibilities. Thus, hazardous travel conditions will
continue tonight and we encourage motorists to stay off the
roads as much as possible.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Windy conditions with northerly winds 30 - 40 mph continue into
Wednesday as the coastal low remains off shore and high
pressure builds eastward. Snow showers in the favorable upslope
area of western New England should finally wind down tomorrow
morning as well. With heights rising aloft and northerly flow
funneling drier air into the area, morning clouds will give way
to some breaks of afternoon sun, mainly in the valley. Breaks of
sun will only enhance boundary mixing so more gusts up to 40mph
could be realized. Will hold off on a wind advisory as our
criteria is frequent gusts 46mph or higher. Otherwise,
temperatures will remain seasonably cool with highs in the mid
to upper 30s due to the cold air advection. Colder temperatures
in the higher terrain expected with highs only in the upper 20s
to low 30s.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As our nor`easter departs, upper-level ridging will build into the
region Wednesday night through Thursday with our area on the
northern periphery of a surface high pressure system. Fair and
seasonable weather is expected during this time.
By Friday into Saturday, a frontal system will approach from the
west with consensus of a low track up the Great Lakes. This will
place the region on the `warmer` side of this system and will bring
mainly rain showers to the region. Some snow showers may mix in
across some higher elevations when temperatures are closer to
freezing. Overall, looking at light precipitation amounts with less
than 0.50 of an inch area wide. Temperatures during this event will
be in the 30s and 40s. As a result of all of this, some melting of
the snowpack is expected which will lead to rises on area rivers and
streams; however, we are not expecting widespread hydrological
issues at this time given the short window for ideal rapid snow
melting. However, we will monitor this as the event gets closer.
Colder and blustery conditions arrive for the weekend as the front
passes through. Some lake-effect snow showers are possible across
portions of the Adirondacks and western Mohawk Valley during this
time. Then another high pressure system looks to arrive early next
week with mainly dry and seasonable weather.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Snow will be ending at the TAF sites by midnight as the coastal
storm that brought today`s snow moves slowly east. Vsbys will
improve to VFR in the Hudson Valley at GFL/ALB/POU by around
midnight, with MVFR conditions lingering at PSF in flurries and
slightly lower cigs. Conditions will continue to gradually
improve during the day Wednesday with clouds breaking to allow
for some sunshine during afternoon as the storm moves away and
high pressure builds east across the Ohio Valley.
Winds will be from the north-northwest at 10 to 15 kts with a
few gusts to 20 to 25 kts tonight. Northwest winds will average
10 to 20 kts during the day Wednesday with a few gusts as high
as 30 kts at ALB.
Outlook...
Wednesday Night: Low Operational Impact. Breezy. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: Low Operational Impact. Slight Chance of SHRA...SHSN.
Friday: High Operational Impact. Definite SHRA...SHSN.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Low Operational Impact. Slight Chance of SHRA.
Saturday Night: Low Operational Impact. Breezy. NO SIG WX.
Sunday: Low Operational Impact. Breezy. NO SIG WX.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Winter Storm Warning until 8 AM EDT Wednesday for CTZ001-013.
NY...Winter Storm Warning until 8 AM EDT Wednesday for NYZ032-033-
038>043-047>054-058>061-063>066-082>084.
MA...Winter Storm Warning until 8 AM EDT Wednesday for MAZ001-025.
VT...Winter Storm Warning until 8 AM EDT Wednesday for VTZ013>015.
&&
$$
SYNOPSIS...Speciale/Wasula
NEAR TERM...Speciale/Wasula
SHORT TERM...Speciale
LONG TERM...Rathbun
AVIATION...MSE/Thompson
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
635 PM CDT Tue Mar 14 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Wednesday night)
Issued at 231 PM CDT Tue Mar 14 2023
Rain is struggling to fall over Deep South Texas today as it
appears dry air is beginning to move into the middle layers of the
atmosphere as high pressure begins to build to our west. However,
HRRR has showers moving over the RGV through this evening.
Therefore, kept isolated to scattered showers in the forecast
through the afternoon and dissipating by sunset. Highs have stayed
in the mid 70s today due to overcast skies. Tonight, lows will be
in the 60s and there will be a lull in the rain chances before
increasing again tomorrow morning. A surface level shortwave
trough moves just to the west of the CWA tomorrow morning. Have a
slight chance of rain for areas west of I-69E. Again, these
showers will be isolated and not everyone will see rain. Tomorrow
is forecast to be mostly cloudy again due to the surface level
disturbance. Highs will also be about the same as today and will
reach the mid 70s with moderate easterly winds. Wednesday night
will be in the mid 60s with mostly cloudy skies.
As for coastal hazards, a High Surf Advisory, a High Risk of rip
currents, and a Coastal Flood Statement are all in effect at least
through this evening. There are breaking waves occurring around 7
feet and water running up almost to the dunes this afternoon.
High tide was around 1:45 PM CDT and waves should continue to
subside. Also, observed water levels did run higher than model
data today and with tomorrow`s forecast of water levels reaching 1
ft, a Coastal Flood Statement may need to be issued again.
&&
.LONG TERM...
(Thursday through next Tuesday)
Issued at 231 PM CDT Tue Mar 14 2023
Overview: Thursday will be the warmest day of the forecast with
widespread upper 80s to middle 90s. A strong cold front will race
through the CWA Friday morning and will bring a chance for showers
and thunderstorms along with much cooler weather this weekend. We`re
talking highs, potentially, not getting above 60 degrees Fahrenheit
in spots over the weekend. Rain chances will also linger Saturday
through Monday. Unfortunately for lingering Spring Breakers, beach
conditions will not be good during the long term. Look for elevated
rip current risk, rough surf, and narrower beaches as water runs up
to the dunes, especially around mid day to early afternoon high
tides. Water is running up on the beaches during high tide now, and
the forecasted tides will only get higher.
The axis of an H5 ridge will mosey east of the region Wednesday
night into Thursday, setting the stage for higher than normal
temperatures Thursday afternoon. Additionally, a low-level jet will
crank up Wednesday night into Thursday, which means gustier
southerly winds for Thursday afternoon. Wind gusts to 40 or 45 mph
are showing up in the forecast grids.
An H5 shortwave moving across the Desert Southwest under a higher
latitude ridge will get absorbed into a larger scale meridional
trough diving out Canada on Thursday. That will support surface low
and cold front development across Kansas. The cold front will race
south Thursday afternoon into Thursday night, picking up a fair
amount of moisture along with it in Northern and Central Texas.
Rain looking more likely late Thursday night into Friday morning,
and used primarily the NBM for the forecast elements. Coastal areas
have the best chance of getting a couple tenths of an inch of needed
rain on Friday, but the front will be through quickly and the window
for substantial rain will not be long. Timing will bring the front
through the lower Valley around 8 to 10 AM Friday morning, and a few
rumbles of thunder and cloud to ground lightning will likely occur
along the front, but with severe weather on the lower probability
side of things. Strong gusty winds will be a possibility, however,
and this could be problematic for beach equipment and Spring Break
activities on SPI on Friday.
Friday`s temperatures could be a little tricky. The cold front is
forecast to swing through Friday morning with the potential for some
heating Friday afternoon, leaving us with high temps in the 60s and
70s. As of now, have sided with the NBM for Friday temperatures, but
a colder trend cannot be ruled out. NBM probabilistic ranges are
wide, and certainty is thus lowered. High temps on Saturday and
Sunday will run in the 50s and 60s under cloudy skies with
additional light rain, supported by a couple of weak short wave
troughs moving overhead. Coastal areas could pick up another tenth
of two of precip over the weekend. Low temperatures inland will be
in the 40s Saturday and Sunday nights, remaining in the lower to mid
50s for the lower Valley and the Island. The NBM shows an outside
(slim) chance, 10 to 20%, of low temps actually getting down to
freezing across the Ranchlands.
Tuesday into Wednesday should bring back a bit more sun and warmer
weather as mid-level ridging approaches, the air mass modifies and
shifts east and winds veer to southeast.
For Spring Breakers, be aware that a high risk of rip currents
appears likely much of the week and into the weekend. On top of
that, elevated surf heights over 6 feet will be possible Thursday
afternoon and prompt an additional High Surf Advisory. Beach
narrowing and minor coastal flooding will be possible Thursday and
Friday.
&&
.AVIATION...
(00Z TAFS)
Issued at 629 PM CDT Tue Mar 14 2023
Expecting a mixture of MVFR and IFR conditions for the rest of
the night and morning. Slight potential for showers in the early
evening for TAF sites, otherwise low level clouds will be the main
concern. Winds are expected to stay mainly out of the east during
the period. Winds will be light overnight, but are expected to
become stronger during the afternoon.
&&
.MARINE...
Issued at 231 PM CDT Tue Mar 14 2023
Tonight through Wednesday Night...Isolated showers are still
possible through the rest of the day until rain tapers off
tonight. Small Craft Advisories are still in effect through this
evening before they winds and seas fall below SCA criteria
tomorrow morning. Then, Small Craft will still need to Exercise
Caution tomorrow and moderate onshore winds should persist.
Thursday through Sunday Night...Marine conditions will remain
less than ideal in the long term. Small craft advisory conditions
will likely be ongoing at the opening of the long term and will
continue into Thursday and Thursday night. A brief improvement
will be possible Friday morning before a strong cold front blows
through the marine domain. Indeed, gales (mainly due to strong
north wind gusts) will be possible behind the front, and strong
north winds and high seas will persist the rest of Friday and into
Friday evening. Admittedly, the pure NBM may be highballing winds
behind the cold front, and may need some adjustment to that aspect
with the next run. Marine conditions will improve slowly Friday
night through Sunday. Though winds will likely drop below
advisory criteria by Sunday, high seas will keep small craft
advisory conditions in play on the Gulf waters through Sunday
night.
&&
.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE 68 76 71 83 / 40 30 10 10
HARLINGEN 65 76 69 88 / 30 20 10 10
MCALLEN 66 75 70 90 / 30 40 10 10
RIO GRANDE CITY 64 74 69 94 / 40 40 0 0
SOUTH PADRE ISLAND 68 73 69 78 / 30 20 10 10
BAYVIEW/PORT ISABEL 67 75 69 83 / 30 20 10 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX... until 9 PM CDT this evening for TXZ451-454-455.
High Rip Current Risk through Wednesday evening for TXZ451-454-
455.
High Surf Advisory until 7 AM CDT Wednesday for TXZ451-454-455.
GM...Small Craft Advisory until 10 PM CDT this evening for GMZ130-132-
135.
Small Craft Advisory until 7 AM CDT Wednesday for GMZ150-155-170-
175.
&&
$$
SHORT TERM...65-Soria
LONG TERM....54-BHM
AVIATION...64-Katz
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1059 PM CDT Tue Mar 14 2023
.DISCUSSION...(This evening through Tuesday)
Issued at 245 PM CDT Tue Mar 14 2023
KEY MESSAGES:
- Accumulating snow likely Thursday into Friday, especially across
eastern Minnesota & western Wisconsin
- Gusty northwest winds Thursday through Friday.
Today through Wednesday...
High pressure overhead has given us a bright but cold day for mid-
March with highs generally remaining below freezing this afternoon.
Much warmer temperatures arrive tomorrow as strong warm advection
develops over the region in response to the departing high pressure &
developing low pressure over the northern plains. The deep snowpack
will put a ceiling on how high temperatures will go, but daytime
highs in the low to mid 40s look likely along with dew points well-
above freezing as southerly flow continuously brings warmer air into
the region. It will still be a fairly raw day despite the warmer
temperatures, a southerly winds gust to 20-30 mph & widespread cloud
cover develops in response to the increasing warm advection.
Advection fog also looks likely to develop by Wednesday evening as we
should start to see some snowmelt as dew point temperatures remain
above freezing. The strong winds will probably keep it from becoming
too dense, & it may end up as low stratus, but reduced visibility
certainly looks possible Wednesday night through Thursday morning.
Thursday-Friday...
The flow aloft becomes quite active Thursday through Saturday as two
waves in the northern & southern streams of the jet become
relatively phased over the Upper Midwest. Models today generally continue
the trend of keeping the two waves separate until they are over the
Great Lakes, keeping the heaviest precipitation & greatest potential
for heavy snow generally east & north of the area. Precipitation
with the first phase of this system should remain north along the
international border, where the northern shortwave over Canada will
generate a swath of accumulating snow across northern Minnesota.
Meanwhile the southern shortwave will develop a surface low over the
central plains, with widespread precipitation developing north of the
low Thursday through Friday. Quite a bit of spread still exists for
precipitation amounts amongst the guidance, owing to the uncertainty
still present in how strongly phased the two waves becoming. A more
phased & slower system would result in heavier precipitation over the
area, perhaps locally as high as 1". Meanwhile the more likely
faster/less phased solutions have lighter precipitation on the order
of 0.25-0.5" across Minnesota & 0.5-0.75" over Western Wisconsin.
Temperatures will likely still be warm enough for precipitation to
initially fall as rain for the first few hours Thursday morning.
However, most of the precipitation is expected to fall as snow with
plowable snow looking likely across most of eastern Minnesota and
especially western Wisconsin. Similar to our last few snows, the
current consensus on timing brings most of the snow through Minnesota
during the middle of the day, which will likely limit accumulation
on roads & treated surfaces until closer to sunset. western Wisconsin
has a better chance of seeing appreciable accumulating snow as the
bulk of the snow there has a better chance of falling after sunset.
Light snow is also expected to continue through Friday across
northwest & north-central Wisconsin as the system begins to deepen &
slow over the Great Lakes. Possible accumulations still carry a good
deal of uncertainty, but in general a slushy inch or two is expected
across much of Minnesota, with amounts of 3-5" becoming more likely
as one goes eastwards from eastern Minnesota through western
Wisconsin. Probabilities for greater than 6" of snow increase across
northwest & north-central Wisconsin, but the heaviest snows should
remain located close to lake Superior.
In addition to the snow, gusty northwest winds will develop through
the day on Thursday & remain strong into Friday. Gusts over 40 mph
are likely across western Minnesota Thursday, although less snow is
expected there which should limit the impacts from blowing snow.
Lighter winds are expected over eastern Minnesota & western Wisconsin
where the best chances for plowable snow exits, however gusts over
30 mph at times will still lead to some visibility issues with the
falling snow.
Saturday-Wednesday...
Light snow showers could linger into saturday as cold cyclonic flow
aloft remains over the region during the weekend. Temperatures will
be quite cold for mid-March with daytime highs below freezing &
overnight lows in the single digits. Temperatures will gradually
warm through the week as heights rise aloft. Models are all over the
place regarding the timing precipitation chances, but at least one
shot for another round of precipitation looks likely.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1052 PM CDT Tue Mar 14 2023
Not many changes from the previous TAF. We continue to follow the
HRRR/RAP for low cloud potential through Wednesday night, which means
little in the way of fog/stratus until the front approaches a
terminal. Only AXN/MSP look to be getting close to the fropa come the
end of their respective TAF periods. Conditions look to deteriorate
quickly once they go sub-VFR. This period is also expected to be dry,
with precip chances starting to show up for the end of the 12z TAF
period.
KMSP...Again, expecting some wind shear issues tonight and again
Wednesday night. Still leaning toward the HRRR idea of low clouds not
showing up until we get closer to fropa. Given the lack of low clouds
anywhere in the northern Plains, it`s likely the LAV is too
aggressivewith bringing in low clouds.
/OUTLOOK FOR KMSP/
Thu...MVFR-IFR. -SN likely, -RA possible AM. Wind NNW 15-20G30 kts.
Fri...MVFR-IFR. -SN possible. Wind NW 15-20G30 kts.
Sat...VFR, MVFR/-SN possible AM. Wind NNW 10-15G25 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...ETA
AVIATION...MPG
Area Forecast Discussion
National Weather Service Reno NV
220 PM PDT Tue Mar 14 2023
.SYNOPSIS...
Snow showers will continue through this evening, especially in the
Sierra where some locally heavy snow showers and an isolated
thunderstorm could put down some fast heavy accumulations.
Very windy all areas this evening. Snow showers and winds will
gradually diminish overnight into Wednesday morning with a break
in the weather through Friday morning. Light showers return in
time for the weekend with a bigger storm possible next week.
&&
.DISCUSSION...
The main AR has shifted south of Mono County already this
afternoon as it takes aim on southern CA. Snow showers will be
driven by orographics/instability as the main upper low tracks
across northeast CA into ID tonight. Best chances for snow showers
will be this evening and very early morning hours Wednesday along
and immediately east of the Sierra crest (spilling over into the
Hwy 395 corridor) and across northeast CA into northwest NV in
line with the main upper low`s track. Enough instability is
present for snow showers along the Sierra to get quite strong and
produce locally heavy snow and possibly some lightning this
evening. So unlike the widespread steady snow associated with the
AR earlier in the day, snow amounts will vary considerably from
one spot to another with light snow or maybe nothing happening one
minute to a fast dumping of snow with several inches of
accumulation real quick. Showers will be more isold-sct across
western NV with enough forcing/instability for a strike or two in
the Basin and Range, mainly east of Lovelock-Fallon.
Snow levels near 7000 feet this afternoon will fall tonight, so
the flood threat is reduced. Another 6-12" is possible around the
Tahoe Basin northward into Plumas and western Lassen County, with
10-20" down along the crest of Mono County. A few inches are
possible for lake level communities in the Tahoe Basin. While
lowest elevations will avoid snow accumulation, the one place to
watch is eastern Lassen County and northwest NV (Susanville-
Doyle-Gerlach area including Hwy 395) this evening as the last
several runs of the HRRR produce a convective shower band along
the front around or shortly after sundown which could produce
showers heavy enough to drag snow levels down to the valley floor
and produce a quick inch or two.
With the drier surge or air aloft, precipitation has cut off or
cut back considerably to the lee of the Sierra. Mixing and
gradients will combine with 700 MB flow near 70 kts to bring very
strong southwest winds to most areas with sustained winds 30-35
mph at times and gusts reaching 45-55 mph over widespread areas.
Windprone areas including Hwy 95 near Walker Lake could see gusts
to 70 mph.
Generally quiet Wed-Fri AM before additional weaker storms bring
some light precipitation and occasional breezy afternoon winds
late Friday into the weekend. Overall temperatures will remain on
the cool side (5-10 degrees below normal). Another bigger storm is
possible Tue-Wed next week. However latest ensemble guidance
(Cluster Analysis and GEFS/EPS IVT Probabilities tools) is
trending the AR more towards southern CA with the northern
Sierra/western NV on the colder side of things.
Hohmann
&&
.AVIATION...
Strong mountain wave turbulence and LLWS will continue into tonight
with wind diminishing and shifting toward the north for Thursday.
Winds could impact RNO operations with sustained surface winds up
near 30 kts from the south, which is a known LLWS issue. Surface
gusts may reach/exceed 50 kts across western NV late this afternoon
into this evening 21-06 UTC.
Band of showers and thunderstorms may develop over Pershing and
Churchill counties this evening (00-06UTC), this may also trigger a
few surface gusts over 50kts and kick up blowing dust off the Carson
Sink.
Sierra showers will transition from rain to snow for TVL and TRK
this evening with accumulations up to 4 inches possible. Showers
activity and IFR/MVFR ceilings should end by early Wednesday
morning.
Depending on how quickly skies clear tonight there is a chance for
fog to develop at or near KTRK Wednesday AM 12-16 UTC.
Rest of the week should favor VFR conditions and light winds. Early
morning fog may develop in Sierra valleys. Next weather systems on
the horizon may arrive over the weekend into early next week. Brong
&&
.AVALANCHE...
* The main AR was shifting southward into southern CA with the
colder main upper trough and instability the primary players in
snow showers through early Wednesday morning. Latest projections
indicate heaviest and best coverage of snow showers through
this evening, gradually tapering from north to south overnight.
Only isolated snow showers and spotty light accumulations are
expected Wednesday with dry conditions Thursday.
* Snow levels were right around 7000 feet and will gradually fall
through the night with colder air associated with the trough.
Snow-to-Liquid Ratios (SLR) near 9:1 to 14:1 early this evening
will rise to 12:1 to 17:1 after midnight, higher ratios above
9000 feet.
* 24-hr Snow Water Equivalent (SWE) 6pm-6am will range from
1.00-1.50" along the crest with the heaviest amounts south of
Sonora Pass. Given the convective nature of the showers tonight,
amounts will vary considerably from one location to another.
Snowfall rates will generally be less than 1"/hr but heavier
cells could reach 2-4"/hr for brief periods.
* Southwest ridge winds will remain quite stout (50-70 mph)
through midnight then turn west and begin a slow decrease
overnight into Wednesday morning (35-55 mph). Gusts in excess of
100 mph this evening, gradually tapering back overnight.
Midslope and valley winds will remain strong this evening as
well with gusts to 40+ mph.
* Quieter most of Wed-Fri AM. Brisk east winds Wednesday night
with gusts 25-35 mph. Light precipitation returns Friday
afternoon into the weekend with another bigger storm possible
early-mid next week.
Hohmann
&&
.HYDROLOGY...
For a nice change of pace this winter, the ongoing atmospheric river
has underperformed in terms of spillover precipitation into our
area. This has lead to a reduction in flooding concerns. The
broad areal flood advisory has been canceled, and replaced with 3
more focused flood advisories and one river flood warning. From
north to south, there is a flood advisory for the Pit River into
Big Valley where increasing flows on the Pit River near Canby are
expected to be augmented by local creeks into Big Valley to cause
minor flooding. A river flood warning is out for the Middle Fork
of the Feather near Portola, where minor flooding has been
reported near Clio, and additional rises are expected. Lastly
there are flood advisories for high flows on the Carson River
below Lahontan Reservoir and on the Walker between Wabuska and
Weber Reservoir. No other flooding issues are currently expected.
Bardsley
&&
.REV Watches/Warnings/Advisories...
NV...Wind Advisory until 11 PM PDT this evening NVZ001-003>005.
Winter Storm Warning until 5 AM PDT Wednesday NVZ002.
CA...Wind Advisory until 11 PM PDT this evening CAZ070.
Winter Storm Warning until 5 AM PDT Wednesday CAZ071.
Winter Storm Warning until 5 AM PDT Wednesday CAZ072.
Winter Storm Warning until 5 AM PDT Wednesday CAZ073.
&&
$$
Area Forecast Discussion
National Weather Service Las Vegas NV
717 PM PDT Tue Mar 14 2023
.SYNOPSIS...An atmospheric river event will bring widespread rain
and high elevation snow along with areas of strong winds to the
southwest states through Wednesday. Dry weather will follow the
rest of the week but additional Pacific moisture will provide
chances for unsettled weather late in the weekend.
&&
.UPDATE...The first wave of precipitation associated with this
system brought a trace - 0.2" of rain to the lower deserts, and 0.5-
1.5" to the higher terrain. The Owens Valley, which was hit hard
with the previous atmospheric river, has received anywhere from 0.1
to 1.25" of rain, with light precipitation ongoing. Spillover
precipitation is expected to continue into the early morning hours,
with an additional 0.25-0.5" possible. Elsewhere across the Mojave
Desert, scattered light showers linger, but more widespread activity
is expected tonight through daybreak. The bulk of this precipitation
should be focused along/south of the I-15 corridor, and in eastern
Lincoln County. An additional tenth or two of rain will be possible,
with locally higher amounts likely in Mohave County. As this wave of
precipitation moves out, breaks in the clouds along with forcing
from a shortwave and colder temperatures aloft is forecast to
produce some instability (possibly up to 1000 J/kg). Latest runs of
the HRRR have been keen on firing scattered storms tomorrow
afternoon. These trends will have to be monitored, as plentiful
shear and low freezing levels would support a hail threat.
Precipitation is expected to move out of the area and/or dissipate
tomorrow night, allowing drier conditions to prevail through at
least Friday. Updated forecast package will be out tonight.
&&
.SHORT TERM...This Evening through Wednesday Night.
The first round of precipitation will continue to move east across
the region this evening before diminishing overnight. After 11 PM
tonight, this first wave should become less organized the better
forcing shifts east and some drier moves in from the west. THe best
chance for continued precipitation and rain impacts overnight will
be in Mohave County and eastern Lincoln County where anomalously
high moisture along with favorable flow will allow for precipitation
to persist and remain semi-organized. There could also be continued
upslope enhancement on the Spring Mountains and Sierra overnight,
however there should be a decrease in precipitation chances and
rainfall rates in the Owens Valley as the strong mid level winds and
higher moisture shifts south and less precipitation overtop the
Sierra Crest. Winds overnight will continue to be gusty as the
strongest pressure gradient with this system moves through. Winds
should drop off quickly Wednesday early morning as the pressure
gradient slacks and the low level winds diminish.
Wednesday and Wednesday night will be an interesting weather set up
as the next wave moves into the area. This shortwave will have less
moisture associated with it but better forcing than this first wave
that we dealing with currently. In addition, the trough will have
colder mid and upper level temperatures associated with it, which
will lead to not only lowering snow levels but some instability.
Dewpoints will remain in the 40F to around 50F south of the I-15
through Wednesday afternoon before the main forcing pushes in
Wednesday afternoon and evening. LIs will become slightly negative
on Wednesday and models show a decent amount of lightning Wednesday
afternoon that will linger into at least Wednesday early overnight.
The main impact from these isolated thunderstorms that develop would
be small hail as the freezing level lowers and enhanced rainfall.
Rainfall amounts Wednesday have increased in eastern San Bernardino,
eastern Lincoln, southern Clark, and much of Mohave County because
of this convective element. Ensembles show very low (10%)
probabilities for rainfall rates over 1inch/hr, and low to medium
(10-30%) probabilities for 0.5inch/hr rates, so there could be a
flooding risk with any heavier shower or thunderstorm but it will be
isolated and depend on where things set up. WPC highlights Mohave
County and far eastern Lincoln County with a marginal risk in the
Day 2 excessive rainfall outlook, which is where the highest chance
for thunderstorms and better instability will be and linger through
the early overnight. Snow levels will decrease to around 7500ft
Wednesday afternoon, and while there is currently only limited
snowfall amounts expected as the precipitation should be winding
down on the Spring Mountains, the convective element and how it will
influence snow levels as well as precipitation amounts will need to
be monitored. Currently think the convection will be displaced to
the east and therefore there will be no changes to the current
impacts on the Spring Mountains, but will need to see how things
develop tomorrow.
Temperatures will cool off slightly tonight and tomorrow, but a
significant cold snap is not expected at this time.
.LONG TERM...Thursday through Monday
A ridge develops over the western United States once the current
storm system moves east. The ridge should send the atmospheric river
away from the forecast area, keeping conditions mostly dry.
Shortwave disturbances moving along the ridging pattern combined
with some moisture left behind by the previous system may lead to
cloud cover and periods of light precipitation, but without a
substantial moisture source measurable amounts at the surface are
unlikely. It appears that the better opportunity for precipitation
will be over the weekend as the ridge breaks down and roughly zonal
flow reaches the southwest United States, but will have to continue
to see how the setup evolves. Both the GFS and ECMWF IVT show better
vapor transport later in the weekend and into Monday, rather than
earlier in the weekend with earlier runs as the breakdown of the
ridge is delayed. Besides that, unseasonably cool temperatures
remain across the area through the weekend as a colder airmass stays
in place.
&&
.AVIATION...For Harry Reid...Periods of rain through the afternoon
will drop ceilings as low as 4000 feet. Rain chances at the terminal
will decrease around 00Z, with the best chances shifting to areas
southeast of I-15 in the Daggett, Peach Springs, and Mormon Mesa
corridors overnight through Wednesday morning. During the day
Wednesday, scattered showers and isolated thunderstorms are expected
to develop, with the greatest chances over the mountains, and a
lower chance at the terminal. Any storm near the terminal could drop
ceilings to 3000 to 4000 feet. South to southwest winds are expected
through Wednesday, occasionally gusting as high as 25 knots, before
shifting to the northwest Wednesday night. Northerly winds gusting
15 to 20 knots are expected Thursday, with quiet weather likely on
Friday.
For the rest of southern Nevada, northwest Arizona and southeast
California...Rain and high elevation snow will spread over nearly
the entire region this afternoon, with ceilings below 5000 feet and
terrain obscuration common, especially north of I-40. Overnight, the
best chances for rain and low ceilings will shift to areas southeast
of I-15 and also in Lincoln County. Wednesday, scattered showers and
isolated thunderstorms are expected, primarily southeast of a line
from Rachel to Death Valley to Barstow. The main threats with
thunderstorms will be erratic, gusty winds and low ceilings with
terrain obscuration. Dry weather and breezy northerly winds are
expected Thursday, with the strongest gusts of around 30 knots in
the Colorado River Valley. Quieter weather is expected Friday.
&&&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Woods
SHORT TERM...Nickerson
LONG TERM...Meltzer
AVIATION...Morgan
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