Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/11/23
Area Forecast Discussion
National Weather Service Quad Cities IA IL
556 PM CST Fri Mar 10 2023
...00z AVIATION UPDATE...
.SYNOPSIS...
Issued at 202 PM CST Fri Mar 10 2023
Latest water vapor loops show upper low responsible for our
precipitation yesterday, rotating across eastern MI and Lake
Erie. While some subsidence allowed for a few breaks in the clouds
this morning for a few hours evident on visible satellite,
cyclonic flow aloft has brought more broken/overcast skies to the
CWA late morning. As a result, temperatures have struggled to
climb much today, especially over new snowpack. Readings at 2pm,
were in the lower to middle 30s.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 202 PM CST Fri Mar 10 2023
Key Messages:
1. Dry conditions with cloudy skies this evening and tonight.
2. Storm system still on track to bring a chance of accumulating
snow north of I-80 Saturday afternoon through Saturday night.
There still remains quite a bit of uncertainty regarding impacts
with this storm.
This Evening-Tonight...cloudy skies and a weak convergent signal
will foster a chance of scattered flurries this evening, mainly in
IL. Otherwise, light winds under 5 kts will be seen with
temperatures dropping into the mid to upper 20s. If any breaks in
the clouds can develop, than these readings may be a little too
high.
Saturday-Saturday night...details below.
Synoptic setup...a strong upper low currently over the
Pacific Northwest on water vapor, will track east over the
Rockies into northern Montana and North Dakota. A sub-1000mb
surface low will develop with this wave. In addition, a weaker
upper level wave will track over the Colorado Rockies and induce a
weak surface low into the Plains. Broad upper ridging and an
increasing pressure gradient will occur ahead of these features
over the local area, with breezy southeast winds developing in the
late morning/early afternoon hours with winds between 10-20 mph.
Clouds will also increase from west to east through the day,
Precipitation type...latest model solutions and thermal profiles
have delayed the onset of precip with this storm into our area
and now expecting the bulk of this event to fall during the
evening and overnight hours Saturday night. Surface temps will be
similar to the last winter storm with readings in the low to mid
30s initially, but then slowly falling throughout the night. Max
wet bulb aloft from the RAP quickly falls below 0C along and north
of I-80 after 23z, with surface wet bulbs quickly following suit.
Expect all snow north of I-80, with a rain-snow mix south of I-80
at onset quickly transitioning to snow a few hours later as the
column fully saturates. There is some concern that the rain-snow
line may be a little further south as noted by the 12z HREF and
could see a quicker transition to snow everywhere.
Timing and Amounts...while this system still has some
disagreement within the 12z deterministic and ensemble runs even
this late in the game, precipitation will start across central IA
and track east through the evening and overnight hours Saturday.
Model QPF consenus has 0.2"-0.3" of liquid for this event. A heavy
wet snow is once again anticipated with low SLRs (8:1-11:1)
resulting in a 1-3 inch snowfall, where snow is the main ptype.
This is currently forecast along and north of I-80 and accumulate
primarily on elevated and grassy surfaces. Locations south of the
interstate will see less than an inch and more of a rain-snow mix.
Taking a look at forecast soundings, the DGZ is not as deep as
the previous winter event yesterday leading to a lower confidence
forecast in snow amounts and impacts. WPC snowfall has also come
in lower than their 00z run last night. However, the 12z GFS and
NAM solutions are outliers with respect to the GEFS/ECS ensemble
and NBM probabilistic output at the moment with much higher
amounts further south. Something will have to keep an eye on for
any forecast adjustments and any potential headline decisions.
Precipitation will quickly come to an end around sunrise Sunday.
Overnight lows will be in the upper 20s to lower 30s.
.LONG TERM...(Sunday through Friday)
Issued at 202 PM CST Fri Mar 10 2023
[Key Messages]
1) Quiet conditions favored through mid-week with below
normal temperatures favored.
2) Warm-up late week with chances of rain returning ahead of a cold
front.
[Discussion]
Storm will exit the area early Sunday with surface high pressure and
ridging aloft following right on its heel. This will promote a dry,
albeit cool, start to the week. Look for highs Sunday through
Tuesday to be in the 30s for most (near to low 40s in northeast MO
and west central IL) with lows dropping into teens (mainly Monday
night) and 20s.
Milder air will return to the area by Wednesday with strengthening
southerly flow and increasing heights aloft. Blended guidance favors
much of the area south of Interstate 80 seeing highs well into the
50s. This will change with the arrival of a cold front Thursday,
which will bring in another cool down and chances for precipitation.
At this time, temperatures and forecast soundings primarily favor
rain.
Dry and cool weather is favored for next weekend with high pressure
building back across the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 552 PM CST Fri Mar 10 2023
MVFR cloud decks will continue to stream acrs the area tonight
into Saturday morning, with northwesterly to north sfc winds
veering around to the east into the early morning hours. MVFR to
VFR clouds continue for much of Sat as the sfc winds become east-
southeast and increase to 10-15 KTs. An incoming precip shield of
snow or rain-snow mix ahead of the next incoming weather system
will make it acrs or in the VCNTY of most of the TAF sites from
west-to-east by late Sat afternoon with a trend back to lower
MVFR decks and VSBYs.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Gross
SHORT TERM...Gross
LONG TERM...Speck
AVIATION...12
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
539 PM CST Fri Mar 10 2023
...Aviation Update...
.UPDATE...
Issued at 523 PM CST Fri Mar 10 2023
Added some patchy fog to the forecast after midnight tonight per
the HRRR and somewhat favorable southeasterly surface winds. While
overall cloud cover and strength of winds will likely keep
visibilities higher than what the HRRR is suggesting, felt it was
worth a mention given the set-up...with some patchy fog expected
(with 1-3 miles of visibility) peaking in coverage just after
daybreak.
&&
.DISCUSSION...(This evening through Friday)
Issued at 346 PM CST Fri Mar 10 2023
Key Messages:
* Freezing drizzle, drizzle, and light snow expected across
portions of the area tonight into Saturday morning with light
rain possible Saturday morning into Saturday afternoon.
* Winter Weather Advisory in effect tonight into Saturday morning
for northern portions of the area.
* Warmer temperatures expected Tuesday and Wednesday.
* Colder temperatures along with precipitation expected on
Thursday.
Mostly cloudy to cloudy skies for most of today have lead to
temperatures being cooler than previously expected so have cooled
high temperatures for today by a few degrees. An upper level trough
currently over the northwestern part of the country will move
eastward over the Northern Plains tonight into Saturday morning.
This will increase upper lift over south central and central
Nebraska and north central Kansas. Southeasterly winds will also
advect in low-level moisture. Expect low temperatures tonight to
range from the upper 20s across central Nebraska to the mid 30s
across north central Kansas. Precipitation will likely start out in
the form of freezing drizzle around 3 am across central Nebraska
with drizzle expanding across the rest of the area by 6 am. Light
snow will also be possible late tonight into Saturday morning for
areas generally along and north of I-80. Light ice accumulation will
be possible across this same area. Little to no snow accumulation is
expected. Forecast soundings across central Nebraska indicate
freezing drizzle will be possible from around 3 am to 11 am so a
Winter Weather Advisory has been issued for that time. Drizzle is
possible across areas that will be above freezing. There is some
uncertainty in regards to precip type due to temperatures hovering
around the freezing mark for areas south of the advisory. Light rain
is expected later on Saturday as temperatures climb above freezing.
Have cooled temperatures slightly below the NBM for tomorrow due
to the presence of clouds and precipitation.
The previously mentioned upper trough will move eastward towards the
East Coast next week. High temperatures Sunday and Monday will be in
the 30s and 40s with winds generally out of the north. Winds will
increase out of the south on Tuesday with a surface trough
developing in the lee of the Rocky Mountains. This will contribute
to temperatures warming up into the 50s and 60s on Tuesday.
Temperatures will warm up even further on Wednesday with highs in
the 60s and 70s expected. The warmup will come to an end on Thursday
as another cold front arrives and another upper trough passes over
the Northern Plains and Upper Midwest. This upper trough will
connect with another upper trough over the Four Corners region. This
will result in an increase in upper lift over Nebraska and Kansas
which will allow for another chance of precipitation. Some of this
precipitation may be of a frozen variety depending on temperatures.
High temperatures on Thursday are expected to cool into the 40s and
50s.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 523 PM CST Fri Mar 10 2023
Lots of cloud cover continues across the region this afternoon
and MVFR CIGS expected to persist into the overnight hours.
Moisture should increase from the south around midnight,
resulting in CIGS lowering to IFR levels along with some BR and
the chance for -DZ through the mid-morning hours. CIGS should
improve just before midday Saturday, with a return to mostly sunny
skies late in the period as model time heights are showing a
sharp cut off in cloud cover by late afternoon behind this next
frontal boundary.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory from 3 AM to 11 AM CST Saturday for
NEZ039>041-046>049.
KS...NONE.
&&
$$
UPDATE...Rossi
DISCUSSION...Schuldt
AVIATION...Rossi
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
949 PM EST Fri Mar 10 2023
.SYNOPSIS...
Dry and cool high pressure will build into the region from the
northwest tonight and Saturday. A stronger low pressure system will
approach the region from the west Saturday night and move through
Sunday into Sunday night, bringing moisture back into the area
for the latter half of the weekend. Colder air will arrive from
the northwest on Monday and persist through the middle of the week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 945 PM Friday: Main change this update was adding the
potential for light snow showers and flurries across the northern NC
mtns overnight. Have been seeing cloud tops along the NC/TN border
gradually cool the last several hours. Cloud top temps look to range
from -9C to -11C across the northern NC mtns this evening. With the
potential for some light wrap around moisture from the departing sfc
low, could see some light snow flurries and showers develop. No snow
accums are expected at this time. The other change needed was
regarding some tweaks to temps and dewpoints to better match the
latest obs. Did a 50/50 blend of the CONSShort and the HRRR temps
and dewpoints to better match obs for the next couple of hours.
Otherwise, sfc high pressure will build into the region tonight with
a narrow gradient situated across the higher elevations. This will
lead to stronger winds and gusts this evening into tonight. Gusts
around 40 kts are possible, especially across elevations above 3500
ft. Thus, the Wind Advisory remains in effect through 10 AM
Saturday. As for temperatures, CAA behind the FROPA will lead to
lows tonight near or below freezing across the NC mountains. The
Piedmont should remain well above freezing, but still remain colder
than the above normal temps the area has felt the past few weeks.
Saturday looks to be dry and cool, with winds gradually tapering off
into the afternoon hours. Meanwhile, upper ridging will start to
propagate across the area on Saturday and continue to keep high
pressure the dominate air mass through the forecast period. Highs on
Saturday will be around 2-5 degrees below climo across the CWA.
Upper level moisture will start to trickle into the western
Carolinas ahead of the next approaching system, but this will mainly
lead to increased cloud cover throughout the day. As for fire
weather concerns, RH values look to dip down into the upper 20s to
lower 30s Saturday afternoon. However, given the recent rainfall
increasing fuel moisture, and wind gusts decreasing through the
afternoon hours, the overall increased fire danger potential looks
to remain low.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 130 PM EST Friday: Deep layer ridge axis will slide across the
CFWA Saturday night, while height falls accompanying broad upper
troughiness will push in from the west. Moisture advection from
the Gulf and associated forcing will traverse into the Southeast
by daybreak Sunday, leading to elevated PoPs in the forecast for
all of the western Carolinas and northeast Georgia Saturday night
through much of the daytime period on Sunday. Weak in-situ damming
will keep conditions cold and should be cold enough to support the
development of snow/sleet around daybreak Sunday along the northern
Blue Ridge Escarpment. Profiles favor a transition to freezing
rain later Sunday morning once warmer air entrains the mid-levels
with increasing west-southwesterly flow. Expect this event to be
self-limiting and should transition back to rain at some point
during peak heating Sunday afternoon, but there should be a long
enough period of time with wintry p-types that a Winter Weather
Advisory will likely be issued for the northern Mountains and Blue
Ridge Escarpment. The area will experience a "Miller-B" system
as a surface low lifts into the OH Valley and Lower Great Lakes
and a secondary low races across the Southeast Sunday. With cold
and dry low-levels present at the onset of precip Sunday morning,
wouldn`t be surprised for wet-bulb processes to be cold enough to
support wintry p-types across some locations in the mountains and
even breaking containment into portions of the I-40 corridor in
the NC Piedmont for a brief period of time Sunday morning, before
transitioning to all rain. The cold air won`t be well established,
so this shouldn`t have much of an impact in the alluded area,
except potentially on social media. Temperatures on Sunday will
be 10-15 degrees below normal for most locations.
The system pushes offshore Sunday night as broad upper troughiness
remains in place across the eastern CONUS. Outside of a few
northwest flow snow showers along the NC/TN border Sunday night,
deep CAA will filter into the region and settle over the region
through the end of the period. Temperatures will be near-normal
Sunday night and Monday, but great radiational cooling conditions
Monday night will allow temperatures to fall 5-10 degrees below
normal. Current forecast has the Monday night low dropping to the
freezing mark at GSP. This would be the first overnight low to
hit the freezing mark since February 18th.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 230 PM EST Friday: Stout CAA and continental high pressure
will remain in control during the early part of next week. With
heights remaining relatively low, expect for only a gradual
modification in the airmass during the medium range. Mostly dry
conditions should prevail during the forecast period. Model guidance
are in decent agreement 7 days out with a longwave upper trough and
attendant frontal system moving in from the west. Otherwise,
temperatures will be near-normal until the middle part of the week,
when heights rises in response to an upper ridge allows most
locations to reach above normal temperatures through the end of the
extended.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: VFR and dry through the 00Z TAF fcst period
thanks to high pressure building in behind a departing cold front.
Winds have already turned NW at KAVL and should turn NW east of the
mtns within the next hour or two. Low-end gusty NW winds are
expected across the terminals this evening into late tonight, with
gusts at KAVL expected to continue through early Saturday afternoon.
These gusty winds should limit fog development overnight. Upper-
level shortwaves will track overhead this evening into tonight
increasing upper-level cloud cover to SCT to BKN. Should see cloud
cover scatter out a few hours prior to daybreak. Could not rule out
a few intermittent low-end wind gusts east of the mtns Saturday
morning into Saturday afternoon. Cloud cover will gradually increase
throughout Saturday as moisture increases ahead of a low pressure
system approaching out of the west. Winds will be light and vrb at
KAND early Saturday morning through the end of the fcst period.
Winds elsewhere should remain NW on Saturday before turning NE
Saturday evening.
Outlook: A low pressure system brings precip and associated
restrictions back Sunday into Sunday night before drier conditions
return early next week as high pressure builds into the region.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Wind Advisory above 3500 feet until 10 AM EST Saturday for
NCZ033-049-050.
SC...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...AR/CP
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...AR
Area Forecast Discussion
National Weather Service Las Vegas NV
157 PM PST Fri Mar 10 2023
.SYNOPSIS...Rain and high elevation snow will continue in the Sierra
Nevada and Owens Valley today, with light scattered rain showers
spreading eastward across the Mojave Desert this afternoon. Gusty
southwest winds will continue through the evening. Conditions will
improve through the weekend with clear skies and above average
temperatures. Next week, another atmospheric river will return
precipitation chances to the region.
&&
.SHORT TERM...Today and Saturday.
Southeastern California continues to experience light to moderate
rainfall this afternoon thanks to an atmospheric river aimed at the
coast. Warm wind coupled with rain-on-snow will accelerate snow melt
in the Sierra Nevada, where extremely above-average snowpack exists.
In this morning`s AFD update, we mentioned a couple of ways the
forecast was slightly off track. (1) Snow levels started off lower
than expected, with Mammoth Yosemite Airport (around 7100 feet)
consistently observing snow. An observer located in Aspendell around
8500 feet has noted wet snow with about a 2:1 ratio all morning. In
the forecast update, went with 5th percentile snow levels to better
align with observations. (2) More moisture spilled over the Sierra
Nevada into the Owens Valley than anticipated. As of 1:45pm PST,
Bishop Airport has received 1.89 inches of rain since the start of
the event, allowing it to break daily rainfall records for the site.
As such, with the forecast update, increased QPF a bit for the Owens
Valley this afternoon. The bulk of the precipitation has occurred,
but can expect another 0.10 to 0.30 inches in Bishop with higher
amounts in southern Inyo County where the highest radar reflectivity
returns of the day are ongoing. Widespread flooding has been
observed in the Owens Valley, with US-395 closed from Bishop south
to the Inyo / Kern County line. Areal Flood Warnings exist along
this route where 2 to 3 feet of water and debris have been reported
on side roads.
The Flood Watch remains in effect for the eastern Sierra Slopes and
the Owens Valley through 4am PST Sunday. Though precipitation will
largely cease past the Sierra this evening, flooding will continue
to be a concern over the next 24-36 hours as run off and snow melt
inundates washes.
In addition to flood concerns, the Winter Storm Warning for the
Sierra Nevada and Winter Weather Advisory for the White Mountains
continue through 4am PST Sunday due to persistent snow accumulations
above 7000 feet.
Through the afternoon and evening, moisture will spread eastward
across the forecast area, increasing PoPs over the southern Great
Basin and Mojave Desert. Valley rainfall totals will remain less
than a tenth of an inch, but higher elevations can see upward of a
half inch. The exceptions are the panhandle of Lincoln County where
the HRRR continues to highlight a robust band of precipitation
setting up late this afternoon and the Spring Mountains, where
upslope dynamics could produce 1-2 inches of rainfall this
afternoon. There is some question in precipitation type on the
Spring Mountains due to the uncertainty in snow levels, but largely
expecting rain below 8000 feet.
Skies will clear west-to-east tonight and Saturday, allowing
afternoon temperatures to warm to above-average across the region.
.LONG TERM...Sunday through Thursday.
Sunday and Monday look like a break in the atmospheric river
action, with zonal flow transitioning to flat ridging and limiting
precip chances to the Sierra and the northern fringes of the CWA,
with minimal to no impact expected. Expect locally gusty westerly
winds in the favored terrain areas such as Barstow and the
Sierra, but not looking like advisory level at this time.
The next AR is still targeting our area Tuesday and Wednesday. On
the positive side, snow levels look a bit lower, hovering around
8000 feet during the heaviest precipitation, and dropping to 5000
to 6000 feet on the back side of the storm. Another round of very
heavy precip is likely for the Sierra, with liquid equivalent
totals of about six inches at the crest. Snow ratios around 12:1
would suggest about six feet of snow at the crest, with a bit less
at the resort level. Barring a significant change in either storm
track or snow levels, Winter Storm Warnings will be needed. Low
pressure passing by to the north on Wednesday (a bit slower than in
previous model runs) should generate enough forcing for some light
precip in the deserts.
There is quite a bit of model spread for Thursday, with solutions
ranging from ridging overhead in the wake of the storm to low
pressure lingering overhead for one more day. Regardless,
impactful weather looks unlikely. Of note, Monday and Tuesday
could be the warmest days since about November 1st for much of the
Mojave Desert. This will promote more mountain snow melt,
possibly keeping creeks and rivers swollen.
&&
.AVIATION...For Harry Reid...South to southwest winds with
occasional gusts to around 25-30 kts will continue through the
afternoon and early evening before diminishing to around 10-20
kts. There is some indication during the overnight and early
Saturday morning period that winds could decrease even more than
forecast and be under 10 kts. If this occurs, the likely timeframe
would be between between 08z and 15z. Southwest winds are
forecast to increase once again after 17z Saturday with speeds
between 10-15 kts and gusts to around 25 kts. There may be a few
showers around into this evening, but the majority will remain
over the higher terrain. CIGS are expected to be around 6k feet
with gradual improvement this evening and overnight.
For the rest of southern Nevada, northwest Arizona and southeast
California...Significant precipitation will continue through the
afternoon across Inyo County with the KBIH seeing low CIGS and
occasional mod-heavy precipitation. Rain chances will diminish this
evening across Inyo County, but lower CIGS are expected to remain
overnight into Saturday along with isolated showers. Elsewhere, look
for CIGs generally around 6k feet or lower with widespread mountain
obscurations. Some improvement overnight, but still remaining at 8k
feet or lower. South to southwest winds 10-20 kts with gusts to
around 30-40 kts over most areas into this evening with winds
diminishing somewhat this evening.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
SHORT TERM...Varian
LONG TERM...Morgan
AVIATION...Gorelow
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