Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/30/24
Area Forecast Discussion
National Weather Service Binghamton NY
935 PM EDT Fri Mar 29 2024
.SYNOPSIS...
Some clouds around tonight with a slight chance of lake effect
snow for portions of central New York late. Dry early Saturday,
then scattered rain showers move into the region late,
especially over northeast PA. Dry weather returns Easter Sunday.
Temperatures turning slightly warmer this weekend.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
930 PM Update...
Lake clouds continue to stream across the region and should
continue through the night. Temps tomorrow were lowered a few
degrees as clouds and a cooler airmass remain across the area
into the afternoon. The rest of the forecast remains on track.
625 PM Update...
Lake effect clouds continue to cover most of the area, with some
clearing moving into the Mohawk Valley. Cloud cover is expected
to continue through the overnight hours, with a very slight
chance of some isolated lake effect snow showers developing
across the western Mohawk valley into the higher elevations
south of the region. Amounts should be nothing more than a
trace if snow does fall. Winds will continue to be somewhat
strong overnight and into the morning hours. Winds 10-15mph
gusting to 25mph will make the early morning temps feel like
they are in the mid teens to low 20s. Winds will slowly
dissipate from west to east as the day progresses, but most of
the morning will feel like temps are in the 20s. Spring like
weather returns for the afternoon with apparent temperatures
climbing back into the 40s and 50s.
345 PM Update
Northwest flow off of the Great Lakes has led to plenty of
clouds around this afternoon for the Twin Tiers on north. The
clouds will continue into this evening before beginning to break
for some clearing later tonight. However, during the overnight
hours there is some support for spotty lake effect snow/flurries
or even some spotty freezing drizzle over portions of CNY. The
HRRR and Canadian hint at this in particular, so slight chance
PoPs (<20%) are in after midnight. Anything spotty that does
develop will dissipate prior to daybreak tomorrow. Gusty winds
out of the northwest will persist through the evening as well
before beginning to ease a little overnight. Lows will fall back
into the upper 20s to near 30 degrees, but factoring in the
breeze, it can feel like it`s in the upper teens to low 20s
first thing tomorrow morning.
High pressure will be in control early tomorrow before shifting
east making way for a weak area of low pressure and upper-level
shortwave. The low is expected to track near or just south of
the CWA late tomorrow into tomorrow evening bringing some light
rain to the area, mainly over NE PA, while the shortwave skirts
by to the north later at night with little in the way of
moisture. Confidence is low in precipitation north of the
Southern Tier, but if any light rain or spotty shower makes it
into the higher terrain and Catskills it can mix with or even
change over to wet snow. With highs tomorrow expected to range
from the mid and upper 40s to the north to the low and mid 50s
south and overnight lows ranging from the upper 20s to the mid
30s little to no snow would accumulate.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
255 PM Update...
Weak high pressure will be centered over the central Great
Lakes Sunday morning, with a stationary front draped across the
Ohio Valley. A pair of weak disturbances will ripple along this
front Sunday night and early Monday, with a chance of rain
showers, mainly in NEPA, especially Monday morning. A few
showers could sneak into the Southern Tier as well, but the
rain chances will be higher the further south of the NY/PA line
you go. Monday night looks to stay dry as well, though clouds
will be on the increase ahead of the next system.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
255 PM update...
More unsettled weather is on the way, particularly Tuesday into
Thursday as low pressure moves from the Mid-Mississippi Valley
into the Lower Great Lakes, and a weak coastal low develops off
the Delmarva Peninsula, strengthening as it heads towards Cape
Cod. The front to our south will lift northwards on Tuesday,
with rain spreading south to north across the area during the
day Tuesday. Southeast flow in the low levels will keep
temperatures warm enough for rain, but easterly flow over New
England will begin advecting cooler air into eastern NY by
Wednesday morning. How cold it gets, and how far west it
penetrates will largely depend on how quickly the coastal low
develops. As it appears now, we may see a rain/snow mix push
into the Catskills and the headwaters of the Susquehanna late
Tuesday night into Wednesday morning, shifting back to mostly
rain during the day Wednesday. Then, as low pressure deepens
over SE New England, colder air wrapping around will change
precip over to mostly snow Wednesday night, with a possibly
elevation-based mix of rain and snow through Thursday. Lots of
moving pieces with this one, and plenty of uncertainty remains
in terms potential for wintry accumulation and associated
impacts. By late Thursday night, wrap-around lake enhanced snow
showers look to develop, potentially lasting into Friday.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
A fairly solid low deck should be in place through the night at
all TAF sites. It is likely that the cloud deck lowers to MVFR
levels soon after sunset at KITH and KBGM, with the possibility
at KELM as well. At this time, KSYR KRME and KAVP have a fairly
low chance for any restrictions. Ceilings should lift and break
up in the 10-14Z timeframe Saturday. A few west to northwest
wind gusts around 20 knots at times as well.
Outlook...
Saturday night...Mainly VFR but restrictions possible from rain
showers potentially changing to snow showers overnight Saturday
and Sunday morning. (Moderate confidence)
Sunday...Mainly VFR; low chance for rain showers. (Moderate
confidence)
Monday through Tuesday...Mainly VFR; chance of showers.
(Moderate confidence)
Wednesday...Showers likely, possibly mixed with snow along with
associated restrictions.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...DK
NEAR TERM...DK/JTC
SHORT TERM...MPH
LONG TERM...MPH
AVIATION...BTL/DK/MWG
Area Forecast Discussion
National Weather Service Des Moines IA
640 PM CDT Fri Mar 29 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Scattered storms tonight with a few marginally severe
- Seasonal Weekend with rain returning Sunday
- Rainfall & storms continue into Tuesday; bulk of severe
potential south of Iowa
&&
.DISCUSSION...
Issued at 242 PM CDT Fri Mar 29 2024
.Short Term /Tonight through Saturday Night/...
Confidence Short Term: Medium to High
Generally on track for some convection over the area by evening
across central to eastern Iowa. Already on satellite, some
destabilization is taking place aloft with the development of mid
level cumulus. The surface boundary remains in place over west
central to southeast Iowa. H850 analysis this morning at 12z showed
a narrow plume of moisture being rapidly advected north within a 40
to 55kt low level jet. Though the moisture is still rather limited
with Td of 0C to 5C, that will increase toward the evening hours as
slightly deeper moisture from northern Texas begins to get closer to
the area. Also, surface moisture at this time remains low with
dewpoints in the 30s to lower 40s in southwest Iowa. Late afternoon
and early evening will see more moisture pooling at low levels near
the front in southern to eastern Iowa. This will help focus
available moisture/lift from central to eastern Iowa this evening
with the help of a H700 wave, another push of warm air advection and
approaching weak surface low. Once storms develop, H700 flow will
push them east later into the evening. Current HRRR operational runs
are forecasting CAPE to peak at 700 to 1200 j/kg early in the
evening from around 22z to 02z, then the area of better instability
advects east with the system. It may take until 23-00z for
initiation, and thereafter a short window of storm potential in our
southeast to east as the storms move out. Overall, some turning in
the winds will give rise to slightly better chances for larger hail
and the HRRR reflects some weak helicity tracks with the elevated
convection. SPC continues with a marginal risk over those areas
this evening. The upper level wave will be east of our area by 12z
with decreasing clouds and some sun on the way for Saturday. Lows
tonight will drop to the lower 30s northwest while the southeast
will hold in the upper 40s. Though tomorrow will feature some weak
northwest flow, little if any cold air advection will follow the
system tonight. Thus, expect another pleasant day to round out the
last few days of March. Highs tomorrow ahead of the more robust
large scale trough will warm to the upper 40s far northwest to the
lower 60s in the south. A sun/cloud mix is on the way for Saturday.
As we approach Saturday night, low pressure will begin to gather
strength over Kansas as the frontal boundary just pushed south of
the state will become more focused again over northern Missouri.
Models are beginning to diverge somewhat on the timing and placement
of the first round of showers and scattered storms Sunday. There is
now a little better consensus on a more southern track of the next
storm system with the GFS deterministic more closely mirroring the
Euro of the past couple of days. As anticipated, the southern stream
is still dominating the preferred path of synoptic energy. With the
lessening chances for precipitation for most of Saturday night, have
cut back on PoPs through the period to 15 to 30%; and mainly south.
Saturday night mins will remain mild with upper 20s north to the
lower 40s in the south.
.Long Term /Sunday through Friday/...
Confidence: Medium
With the models now coming into better consensus of a more southern
track, the risks of any additional severe weather over our area is
lessening. The main challenge now is the evolution of the system and
how rapidly the low strengthens. This will make the difference
between 1 to 1.5 inches of rainfall versus 2 to 3 inches of
rainfall. The GFS continues to quickly amplify the H850 system prior
to it tracking near Iowa, rather than the Euro which deepens the low
as the low is exiting east of the Mississippi River. The 12z
deterministic Euro continues to amplify the low later with the bulk
of the expected qpf east of Iowa. The 12z GEFs supports some heavier
totals in the southeast/eastern areas of Iowa including a portion of
our southeast. That being said, the trends continue to suggest a
slightly slower amplification which would keep rainfall totals
roughly between 1/2 inch to 2 inches across the south while the
north receives a couple of tenths to up to a half inch in some
areas. The Euro deepens the system much more as it gets into
northern Ohio with a decent cyclone and stronger area of low
pressure. Temperatures will be cooler with the low tracking farther
south. Highs Sunday are anticipated to mainly in the 50s and with
higher chances for showers and some thunder Sunday night into Monday
night, highs are again likely to remain in the 50s for Monday.
Breezy conditions will also develop within northwest flow Monday as
the deepening low departs. By Tuesday there is a hint of a northern
stream trough possibly swinging around the parent upper low. Due to
the differences in model spread progression east of the region, this
feature may not impact Iowa at all. If it does, an area of light
rain or snow would accompany the weak wave. Our blended approach
keeps a chance of light precipitation east, otherwise the remainder
of the forecast sees a drying trend until late week. With that
temperatures will initially be rather cool in the lower to mid 50s
for Tuesday and Wednesday, then transition to a moderating trend by
late week. We may need to trim back expectations a bit and delay the
rapid warming depicted by the NBM with todays model runs slowing the
large system across the eastern CONUS.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 633 PM CDT Fri Mar 29 2024
VFR ceilings were widespread across central IA due to expansive
mid and high cloudiness at 00z. This should persist through the
evening with scattered showers and a few storms developing
southeast, mainly near KOTM, during the evening. Thunder is
possible there, but has been omitted for the time being until
confidence in location and occurrence increases. A brief period
of MVFR stratus may brush KALO Saturday morning, but otherwise
confidence is fairly high for VFR conditions later in the day.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
DISCUSSION...REV
AVIATION...Small
Area Forecast Discussion
National Weather Service Grand Forks ND
1032 PM CDT Fri Mar 29 2024
.KEY MESSAGES...
- The chance for freezing drizzle has fallen to below 10 percent
the rest of the night.
&&
.UPDATE...
Issued at 1030 PM CDT Fri Mar 29 2024
Wind shift axis from a east or southeast wind to a more
northwest wind is roughly from SW Manitoba to about Langdon to
Crookston to near Wadena. Any risk of freezing drizzle I think
is near or just northeast of this area. Brandon MB hints at some
light fzdz and ocnl 3-5sm comes from Cando and Rolla so did keep
some fzdz in grids til late tonight in far NE ND along MB
border.
&&
.DISCUSSION...
Issued at 320 PM CDT Fri Mar 29 2024
This afternoon-Tonight:
Initial ongoing impacts are related to snow that is transitioning
east out of northeast ND and across northwest MN. Ground
temperatures and an initial dry layer have played a role in limiting
accumulations in many locations, but where moderate to heavier snow
rates occur visibilities have dropped as low as 1/4 mile and it has
overcome these ground temperatures. There have been a few reports of
rain and ice pellets, but ice accretion has not be reported from
this as ground temperature remain higher. Highest rates are
associated with frontogensis within the northern axis of WAA that is
transitioning mainly along and north of Highway 2 and is shown to be
out of our region by mid evening.
Soundings show a period of 1-3hr of deeper saturation within the -1
to -7C range on the back side of this exiting precipitation which
could support light drizzle processes, but this also correlated with
locations/timing of above freezing surface temperatures before
sunset. Later this evening when most locations should be below
freezing the depth of this layer is much shallower and in the case
of the RAP it is showing a drier BL and mainly just stratus, which
wouldn`t support drizzle/freezing drizzle. HREF/NBM no longer show
any potential for ice accretion during the overnight/early morning
period Saturday, further lowering confidence in freezing drizzle
impacts. I don`t want to pull back messaging completely as there is
still the window immediately behind the exiting snow and NAM holds
the saturated layer a bit longer than RAP.
Sunday-Sunday night: Westerly flow is favored over eastern ND and
northwest MN, so while there is a progressive wave moving out of
southwest flow into the plains ensemble consensus now places this
well south of our region, and NBM only shows a 20% chance for a
light wintry mix near the South Dakota border/west central MN
region. The chance for minor travel impacts currently is less than
5% in those areas, and recent trends in HREF lower confidence in any
impacts in our area.
Monday-Friday: Large scale patter is now to become dominated by
upper level ridging by late next week. NBM shows 50s and 60s
becoming common by the end of the week with predominantly dry
conditions. There are no sensible weather impacts outside of
possible fire weather concerns during the daytime periods (lower
predictability of RH/winds at this range in this pattern).
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 633 PM CDT Fri Mar 29 2024
Cigs will continue to hover around the IFR/MVFR threshold
through the next several hours with heights from 800 to 1200 ft.
Precip is largely done for all taf sites but some lingering
light snow in both BJI and TVF will move out by 0200Z. A shift
to northwest winds will happen at all sites between 0400z to
1000Z, soonest in the west. Cigs lift back into MVFR territory
around this time as well though little improvement is expected
beyond this. Had enough confidence to include a period a gusts
into the upper teens for DVL though not quite enough for areas
to the east like GFK and FAR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Riddle
DISCUSSION...DJR
AVIATION...TT
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
947 PM EDT Fri Mar 29 2024
.SYNOPSIS...
An oscillating frontal boundary will remain across the region
through the weekend and into early next week. A series of low
pressure systems moving east along the boundary will lead to
occasional chances for showers and thunderstorms over the next
several days.
&&
.NEAR TERM /UNTIL 12 PM SATURDAY AFTERNOON/...
Mid/upper level shortwave trough over MN/IA this evening will
progress rapidly downstream atop a flat mid level ridge, and
cross the Great Lakes by later in the night. Strong west-
southwesterly low level jet in excess of 50kts will drive the
development of showers and storms upstream over IL/IN in a few
hours, and these will cross into Ohio toward daybreak. Before
then, increasing theta-e advection well aloft may allow bands of
very high based sprinkles or light showers to develop and move
across areas north of the Ohio River. Expect the steadier rains
to move into the west-central Ohio area around 5 AM, and spread
southeast on the nose of the low level jet thereafter, mostly
during the morning hours on Saturday. Should see measurable rain
as far south as Wilmington and Chillicothe, though it will tend
to be steadier/heavier/longer duration along and north of I-70.
Areas south of the Ohio River have the best chances of staying
dry. Not an overly great sounding profile for thunder inclusion,
given the voracity of the vertical motion on the nose of the low
level jet, can`t rule it out with a few HRRR runs showing low-
end MUCAPE developing as that most intense vertical motion
passes by.
&&
.SHORT TERM /12 PM SATURDAY AFTERNOON THROUGH 6 PM SUNDAY/...
The surface low mentioned in the near term forecast continues
moving east across the lower peninsula of Michigan on Saturday.
This low track will allow the warm front to lift completely
north of the area during the morning leaving the entire Ohio
Valley in the warm sector south of the low on Saturday. After
the initial surge of forcing associated with the LLJ just south
of the warm front Saturday morning, rain chances drop by mid to
late morning due to lack of forcing. Rain chances are then
forecast start increasing later into the afternoon and evening
hours as a trailing cold front southwest of the low dives into
the Ohio Valley from the northwest. MLCAPE is likely to be low
ahead of the front which suggests the chances for severe storms
remains very low despite strong sheer being in place. Forecast
highs on Saturday range from the middle 60s near I-70 to the
lower 70s south of the Ohio River.
The cold front will continue pushing south through the area Saturday
night leading to continued chances for showers and thunderstorms.
Forcing is not strong and instability is likely to be lacking so the
threat for severe storms and flooding is low. There is some forecast
uncertainty surrounding how far south the front may get Saturday
night. Mesoscale models are suggesting the front makes it to the
Ohio River by daybreak, but this might be a little aggressive since
the low associated with the front will be filling overnight.
Forecast lows will vary greatly. Areas that get on the north side of
the front should drop into the 40s while areas south of the front
remain in the 50s all night.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Quite an active pattern in store for the extended forecast with
multiple rounds of weather to watch.
By Sunday morning, quasi-zonal mid level flow will be in place over
the Ohio Valley. The cold front that stalled out near the Ohio River
on Saturday will begin to lift back north as a warm front associated
with a potent system off to our west. A robust temperature gradient
will be in place over the ILN CWA on Sunday, with areas north of I-
70 only reaching highs in the 50s while areas along the Ohio river
reach the mid 70s.
As the warm front lifts, it will be marked by a notable increase in
theta-e as we head into Sunday afternoon and PWATs rise accordingly,
reaching +1 to 2 sigma anomalies by Sunday afternoon. This influx in
moisture results in mostly cloudy skies for much of the area. MUCAPE
values in the open warm sector look to reach around 1000 J/kg during
the afternoon with low/mid level lapse rates around 7-8 C/km.
However, forecast soundings suggest an elevated mixed layer in place
which may, at least initially, inhibit storms from firing off.
However, should storms develop later in the day, isolated severe
will be possible, with a particular emphasis on hailers given
parameters mentioned above.
Periods of rain/thunder continue into the overnight hours along the
frontal boundary , with ILN still eating the temperature gradient
(lows in the upper 40s in the north, low 60s in the south) as at
least part of the CWA remains in the open warm sector of system to
our west.
Monday arrives with an additional influx of moisture and PWAT
anomalies rise to nearly 3 sigmas above normal. Cloudy skies,
periods of rain and storms continue, along with yet another tight
temperature gradient across the area (lows in the upper 50s in the
north, mid 70s in the south). There is still a bit of disagreement
between ensemble model runs on where the swath of highest QPF will
fall (and when!) but the consensus seems to be that the area will
receive much of its anticipated rainfall between Monday and Tuesday,
with rounds of repeated storms training over areas. With that being
said, soils are fairly dry at the moment, however, some of the
higher end broadbrushed QPFs reach upwards of 3 inches which could
produce isolated flood threats.
The mess continues into Tuesday as the parent low pressure and
associated upper level trough finally moving into the Ohio Valley.
Right now, track of the low still varies between ensemble guidance
so there is some discrepancy on how much we get warm sectored.
However, it does seem like there is a decent chance that at least
some of our CWA will be in a warm and unstable airmass prior to the
low`s cold front moving through, continuing the chance for severe
storms on Tuesday ahead of the front. At the very least, a strong
pressure gradient and LLJ at 60+ kts will be moving through, so we
can anticipate some gusty winds likely making it down to the surface
Tuesday and then again on Wednesday, in the cold air advection
regime.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions expected through about 12Z Saturday, as mid and
high level clouds will thicken as they drift over the TAF sites.
A warm front across the area will mean differing winds at the
respective airfields early this evening before a weakening of
the winds by 03Z negates some of the meaningful differences.
Until then, southerly winds at CVG/LUK, and light north/east
winds at ILN/DAY/LCK/CMH that will tend to turn southeast
through the night.
There is a lower end low level wind shear signal showing up
across the area in the 09Z-15Z timeframe tonight and tomorrow
morning, with the best potential at CVG/LUK where LLWS was again
included in the TAFs there. At the remaining sites, not quite
the magnitude/duration of LLWS as the low level jet weakens as
it gets farther north/east into the area tomorrow morning, so
kept it out of the TAFs.
Area of showers/rain will spread across the northern TAF sites
late in the night and through Saturday morning. Introduced some
TEMPO IFR visibility restrictions in moderate/heavy rain for a
few hours at CMH/LCK given higher confidence. Ceilings across
the area should lower into the low VFR/high MVFR range as the
rain moves through, though it should be lighter rain at DAY/ILN
and brief/lighter showers at CVG/LUK.
Winds will increase through the morning hours as they turn
southwesterly, becoming gusty up to 25kts which will continue
into the afternoon as they shift westerly by later in the day.
OUTLOOK...MVFR/IFR conditions possible along with a chance of
thunderstorms Sunday through Tuesday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Campbell/JGL
NEAR TERM...Binau
SHORT TERM...Campbell
LONG TERM...CA
AVIATION...Binau
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
845 PM CDT Fri Mar 29 2024
.KEY MESSAGES...
- Scattered showers and storms are possible tonight, with the best
chance (60%) being north of I-74. A few storms could be strong
to severe north of I-72 (5% chance of 1" hail).
- Additional thunderstorms are likely on Sunday (70%) and Monday
(90%). Severe weather is possible on both days, but the specific
timing and strength of storms at any one location remains
highly uncertain.
- Temperatures cool next week, with a 30-50% chance of low
temperatures below freezing Tuesday and Wednesday night.
&&
.UPDATE...
Issued at 842 PM CDT Fri Mar 29 2024
Warm front is draped roughly along/north of the I-74 corridor this
evening. KILX VWP is picking up on 50kt low level jet which is
helping to produce scattered thunderstorms mainly along the
Mississippi River Valley this hour. Storms should continue to
expand in coverage and spread east as the LLJ strengthens and
veers over the next several hours. Best focus of storms locally
should be near and north of the I-74 corridor though a few spotty
showers and storms will be possible further south through the
I-72 corridor. Latest RAP indicates most of the instability is
currently located to our west, but around 400-600 J/kg MUCAPE
rooted between 700-800mb will overspread the area late this
evening and overnight. Steep mid-level lapse rates sampled by 00Z
sounding of 8.4C/km would still support some robust updrafts and
an elevated hail threat appears to be in play still for tonight.
Deubelbeiss
&&
.SHORT TERM... (Through Late Saturday Night)
Issued at 307 PM CDT Fri Mar 29 2024
Early Fri afternoon, a broad sfc low was present over the central
Plains, with a warm front draped across IA and into IL,
positioned north of the I-74 corridor as of this writing. As the
sfc low lifts northeast tonight and a stout low-level jet
develops, widespread showers and scattered storms are expected to
develop along the warm frontal zone. Much of the previous forecast
for this activity remains on track. Guidance continues to suggest
widespread precip activity north of I-74, becoming more scattered
south from there. The warm sector will feature modest instability
(MUCAPEs generally under 1000 J/kg) and shear (40 knots) to
support an isolated severe threat as far south as I-72. Hail is
the main concern, but wouldn`t rule out some isolated stronger
wind gusts. Guidance shows the LLJ producing 50-60 mph winds just
1500 feet above the sfc, so while forecast soundings show a
shallow low- level stable layer, if an isolated stronger downdraft
were to develop it could transport these stronger winds to the
sfc.
With widespread cloud cover and continued southwesterly flow
overnight, lows will be quite mild, in the mid 50s. Precip will
exit to the east early Sat morning as a weak cold front swings
through the area. Despite this "cold" front, temps remain warm on
Sat with highs ranging from mid 60s to mid 70s. The front is
expected to stall across southern IL and begin lifting back
northward in the evening, at which point scattered precip will
again be possible. Severe thunderstorms are not expected during
the day Sat or on Sat night.
Erwin
.LONG TERM... (Sunday through Next Friday)
Issued at 307 PM CDT Fri Mar 29 2024
A highly amplified trough is expected to progress across the
southwestern US this weekend, with strong model consensus that a
sfc low will form in the lee of the Rockies on Sunday. Downstream,
subtle upper level ridging will be positioned over the Midwest,
while a sfc warm front extends eastward from the developing sfc
low across Illinois. The exact latitude at which the sfc warm
front sets up on Sun and Mon remains a key source of uncertainty
in the forecast.
After examining the latest GEFS members, as well as the last
several deterministic runs of the GFS/NAM, the most likely
scenario for Sun is the warm front draped somewhere between I-74
and I-70. A weak impulse is progged to round the aforementioned
subtle ridge over the Midwest on Sun, which could aid t-storm
development during the day. Robust wind fields will be in place,
resulting in ample deep layer shear over 50 knots. However, the
winds are forecast to be relatively unidirectional in the lowest
0.5 to 1 km, which should limit the tornado potential. The
exception is in the immediate vicinity of the warm front, where
localized backing of the sfc winds would enhance the low-level
shear. While the deep layer shear profiles are impressive, the
thermodynamic support is less so, with MUCAPE values approaching
(but generally less than) 1000 J/kg. While sfc dewpoints may climb
into the 60s, the low-level moisture doesn`t look particularly
deep and could be prone to reduction via mixing. Another factor
limiting the instability on Sun is the presence of a "CAPE robber"
inversion (an inversion above the level of free convection, in
this case in the 700-800mb layer), which was evident on both
NAM/GFS soundings. In summary, severe storms are possible on
Sunday (currently a marginal, level 1 of 5 risk), but there are
some limiting factors (instability) and uncertainties (specific
placement of the warm front).
Forecast uncertainty increases for Monday. All signs point to
increasing severe thunderstorm potential as continued moisture
return across the warm sector increases instability, and the
approaching deep trough/associated low pressure result in
strengthening kinematic fields and forcing for ascent. The big
question that remains is: how far north will the warm sector be?
Ensemble spread on the latitude of the warm front increases on
Mon, and other uncertainties like the diurnal timing of any
storms further complicates this forecast. With little consistency
between models or model runs, probabilistic guidance becomes
particularly useful for communicating the range of outcomes. So
with the understanding that this front could still set up anywhere
within our CWA, will note that Grand Ensemble joint probability
of meeting specific instability (SBCAPE at least 500 J/kg), shear
(at least 40 knots), and inhibition (CIN greater than -25 J/kg)
thresholds is highest along/south of I-72 (30-40%). Also noticed a
southward shift in the GEFS instability probabilities, so if
there`s any signal in this uncertain forecast, it seems to be a
trend towards the severe potential being highest south of I-72 on
Monday.
This system is progged to bring a cold front through the CWA on
Tues, ushering in cooler air and the potential for freezing temps
during the middle of next week. NBM probabilistic guidance
continues to highlight a 30-50% chance of sub-freezing lows north
of I-72 Tues night, and a 30-50% chance area-wide on Wed night.
There is some potential to see snow on the backside of the system
as well. The latest Grand Ensemble shows a 30% chance of snow
along/north of I- 74. That will depend on the timing of cold air
and the departure of precip though, which remains highly
uncertain at this range.
Erwin
&&
.AVIATION... (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1225 PM CDT Fri Mar 29 2024
The beginning of the TAF period will be decently calm and basically
clear skies. After 00z this evening, a system will move into central
IL bringing VCSH, VCTS, and WS into all sites. The WS should end by
sunrise (10-13z) tomorrow morning. Winds will be gusty as the low
pressure system passes. Winds will shift from SE to WSW by the end
of the TAF period. BMI and CMI could see a bout of MVFR ceilings
near the end of the period. With any stronger thunderstorm that may
move through a site, visibilities and ceilings could drop
substantially for a short period of time. Uncertainty of when/if it
will occur is why it is left out right now.
Delaney
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service San Francisco CA
420 PM PDT Fri Mar 29 2024
...New AVIATION, MARINE...
.SYNOPSIS...
Issued at 237 PM PDT Fri Mar 29 2024
A low pressure system with gale force winds is located
approximately 250 miles to west of San Francisco. As this system
approaches, it will bring widespread moderate to locally heavy
rain, gusty winds, and a few thunderstorms. Moderate impacts are
anticipated including minor flooding in urban areas and some
potential for tree/power line damage. Remember to stay up to date
on the current forecast and prepare for longer afternoon and
evening commutes.
&&
.SHORT TERM...
(This evening through Saturday)
Issued at 237 PM PDT Fri Mar 29 2024
The latest surface analysis from the Weather Prediction Center shows
the low pressure system located approximately 250 miles west of San
Francisco. Radar shows prefrontal widespread moderate to heavy rain
showers have developed ahead of the surface warm front. Showers have
already reached portions of the North Bay and San Francisco
Peninsula with 6 hour rain totals between 0.5-0.9 inches in portions
of the North Bay and Santa Cruz Mountains. These showers will
continue to move inland over the next several hours. The warm front
is expected to pass through the SF Bay Area by the late afternoon
(approximately 4-5 PM).
After warm frontal passage, destabilization is expected to occur
over the marine environment and thunderstorm chances increase
significantly. Model guidance from the HRRR suggests that as the
atmosphere destabilizes over the marine environment, convection will
become more scattered and allow for the development of isolated
stronger thunderstorms. The best window for thunderstorm development
has shifted slightly later from this morning with the best window
(20-35% chance) now occurring between 5PM this evening through 8PM
on Saturday. Current data from SFO and KMUX shows moderate surface
to 6km speed and directional shear, suggesting the formation of a
more favorable environment for thunderstorm development. As a more
strongly sheared and higher CAPE environment develops over the
marine environment, the likelihood of waterspout development
increases so we cannot rule out the potential for a landfalling
waterspout.
Velocity radar data shows widespread winds between 30 to 55 mph
moving onshore with the potential for locally higher winds to
develop due to terrain or shower influences. A Wind Advisory remains
in effect until 5AM Saturday for gusts 50+ mph in the highlands
(elevated interior terrain and coastal mountains) and 45+ mph in the
lowlands. A High Wind Warning is in effect along the Big Sur coast
for gusts up to 60 mph. As these strong, gusty winds move inland
there is increased likelihood of damage to trees and power lines.
Nuisance flooding may occur as heavier showers move through urban
areas but widespread river flooding is not expected.
Remember to stay up to date with the forecast and any
watches/warnings as the system continues to move through our area.
&&
.LONG TERM...
(Saturday night through next Thursday)
Issued at 237 PM PDT Fri Mar 29 2024
Scattered showers will continue Saturday into Sunday with elevated
thunderstorm chances continuing until 8PM on Saturday. While
thunderstorm chances are slightly lower on Saturday (20-25% chance)
than Friday (20-35% chance), cannot rule out the possibility of
isolated strong thunderstorms developing. Given the scattered nature
of these showers, some sunny breaks in between showers may be
possible, but remember to stay weather aware and carry an umbrella
with you in preparation for additional future showers. For
hydrologic concerns, some potential remains for nuisance flooding
overnight Friday into Saturday particularly if stronger showers
move over urban areas.
Showers will start to lighten up throughout the day on Saturday with
light showers expected through early Sunday morning. By Sunday
morning, most showers will have departed the area but a few isolated
light showers (< 0.1 inches) may linger into the early afternoon
hours. Winds will start to relax heading into Sunday as the pressure
gradient weakens. Temperatures will be on the cooler side with highs
in the upper 50`s to low 60`s and lows mostly in the 40`s.
Sunday through Thursday:
High pressure will start to build during the early work week and
bring in drier, warmer weather across the region. Guidance hints
that unsettled weather will return towards the end of the work with
cooler temperatures and some light rain possible.
&&
.AVIATION...
(00Z TAFS)
Issued at 419 PM PDT Fri Mar 29 2024
Moderate to heavy rain associated with an occluded front continues
to move through the interior East Bay, the South Bay and down
through the Central Coast. MVFR ceilings and showers are developing
behind the front, with an increasing chance of thunderstorm activity
into Saturday. Strongly gusty southeasterly winds continue for the
rest of the day, with winds diminishing somewhat overnight before
turning more easterly and becoming gusty again Saturday. Wind shear
across the Bay Area should begin to diminish as the main frontal
system passes.
Vicinity of SFO... Radar returns show that the main frontal rain
band has moved to the east of SFO. Expect showers through Saturday
and a chance for thunderstorms through the evening hours tonight, a
lesser chance returning on Saturday. Conditions will predominantly
remain VFR with some chance of MVFR if a shower forms at the
terminals. Strong gusty southeast winds will continue across the
terminal through the night and will begin to turn to the northeast
and diminish Saturday afternoon and evening. AWW is out through 2Z
but may need to be extended pending evolution of local thunderstorm
activity.
SFO Bridge Approach... Similar to SFO.
Monterey Bay Terminals... VFR to MVFR in rain showers. Gusty
southeast winds continue through the TAF period with a brief early
morning lull at MRY. Continuing to monitor SNS winds with the
continuing southeast orientation. Chance of thunderstorms now
through Saturday morning.
&&
.MARINE...
(Tonight through next Wednesday)
Issued at 419 PM PDT Fri Mar 29 2024
A low pressure system continues to approach the California coast.
The main band of moderate to heavy rain and gale force gusts is
moving through the waters and will pass by the evening. Cold,
unstable air aloft with the low will also result in a slight to
moderate chance of thunderstorms this afternoon, tonight and
Saturday. Isolated severe thunderstorms, with increasing
potential for hail and a slight potential for waterspout
development, will increase in likelihood through the evening. A
high pressure system will build in behind the low late in the
weekend and early next week bringing drier, milder conditions to
the area.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 5 AM PDT Saturday for CAZ006-504-509-510-512-
514>516-518-528>530.
Wind Advisory until 3 AM PDT Saturday for CAZ502-503-505.
High Wind Warning until 9 PM PDT this evening for CAZ517.
Wind Advisory from 9 PM this evening to 5 AM PDT Saturday for
CAZ517.
PZ...Small Craft Advisory until 9 PM PDT this evening for SF Bay N of
Bay Bridge.
Gale Warning until 3 AM PDT Saturday for Mry Bay.
Gale Warning until 9 PM PDT this evening for Pigeon Pt to Pt
Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt
Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt
Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
&&
$$
SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...DialH
MARINE...DialH
Visit us at www.weather.gov/sanfrancisco
Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/nwsbayarea
www.twitter.com/nwsbayarea
www.youtube.com/nwsbayarea
Area Forecast Discussion
National Weather Service Reno NV
252 PM PDT Fri Mar 29 2024
.SYNOPSIS...
An impactful weather system continues to bring periods of mountain
snow and valley rain with some snow mixed in at times through the
holiday weekend. Hazardous traveling conditions are expected as a
result particularly in the Sierra Mountain passes. Following a few
days of warmer and drier conditions to begin the work week, there
looks to be potential for more precipitation chances later in the
week along with cooler temperatures.
&&
.DISCUSSION...
While looking at the latest RAP analysis, the CWA currently has a
southwesterly flow aloft with an upper air low spinning off the
coast of CA this afternoon. Going through the rest of today, model
guidance projects the upper air low to travel south just off the
central CA coast going through the nighttime hours and turning the
CWA`s upper air flow more south-southwesterly. On Saturday, models
forecast the low continuing south-southeast down the CA coast a bit
until it splits with one center tracking across the southern portion
of the CWA and the other moving across southern CA on Saturday night
and into Sunday morning. Going through Sunday, forecast guidance
shows the low moving eastward away from the CWA allowing for the
upper air flow to turn north-northeasterly by the late afternoon
hours.
At the surface, a surface low off the coast of CA will allow for
periods of mountain snow and valley rain with some snow mixed in at
times within the CWA continuing through the rest of today and going
through Easter Sunday. Snow levels across the CWA look to be around
4500-5500 ft going through tonight with eastern portions seeing 5500-
6500 ft during the night. The 12Z run of the HREF shows potential
snow rates of around 0.5 inches per hour for a few hours overnight
in areas it snows along and west of the CA/NV border while the
Sierra crest may see up to around 1-1.5 inches per hour. There may
be some locally higher rates possible as well in some locations.
For Saturday, the HREF currently shows snowfall rates mostly under
1 inch per hour across the CWA though there are some 1 inch per
hour rates seen during the late afternoon and evening. There
continues to be some concern late for potential convective cells
during Saturday that may allow for some bursts of heavier
rainfall/snowfall due to the location of the deformation zone
along with models showing an unstable environment. Will continue
to monitor this though western NV seems to be the area of
potential for this to occur at this time. On Easter Sunday, models
have the surface low tracking eastward over the Great Basin
allowing for better precipitation chances in the eastern portions
(50-60%) with the remainder seeing around 10-40% during the
morning hours. During the late afternoon, southern half of the CWA
sees around a 40-50% chances of precipitation before tapering off
going into the night. For more information on the expected
snowfall totals for the holiday weekend as well as the current
Winter Storm Warning and Winter Weather Advisory products in
effect, please visit www.weather.gov/rev/winter.
After the weekend system, models depict a positively tilted upper
air ridge moving onto the Pacific Coast on Monday morning that
continues an eastward progression through the day as well as Tuesday
with its axis passing over the CWA during Tuesday evening. With this
setup above, the CWA expects to see mostly sunny skies along with a
warming trend beginning on Monday that looks to last into the first
part of Wednesday on which some locations in northwestern NV may
reach the lower 70s for daytime highs.
On late Wednesday afternoon, long term models show an upper air
trough moving into the Pacific Northwest turning the CWA`s upper
air flow to southwesterly. At the surface, a potential cold front
looks to pass through through the CWA sometime late Wednesday or
even early Thursday. Long term models show good uncertainty on
Thursday and going through Friday as the GFS shows the trough
beginning to close off into a low over northern CA on Thursday
afternoon and then moves over CWA on Friday. As an alternative,
the ECMWF continues the trough through Thursday before closing it
off into a low on Friday over the northern portion of the CWA.
While the weather pattern is unsettled this far out, there looks
to be the return of precipitation chances later in the work week.
There also looks to be some chances of gusty winds with the NBM
showing 50-60% probabilities of wind gusts of 55 mph or higher on
Thursday. Will continue to monitor this weather pattern in future
model runs to see when better model agreement comes about.
-078
&&
.AVIATION...
With this weather system impacting the region, multiple periods of
mountain snow and valley rain with some snow mixed in that will
cause sub-VFR visibilities at KTRK and KMMH this afternoon with
the remaining REV terminals joining in during the evening with
these conditions lasting through tomorrow morning. Breezy
southerly winds are expected at the surface that look to become
lighter this evening and going into Saturday. FL100 winds expect
to south-southwesterly around 25-35 kts through tonight before
turning east-southwesterly around 15-25 kts on Saturday.
-078
&&
.AVALANCHE...
An impactful weather system continues to affect the region for
the rest of today and brings multiple waves of precipitation
through Sunday afternoon.
* Liquid totals (SWE): For Mono county above 7000 feet, around 0.50-
1.75 inches from Friday evening through Sunday afternoon. For the
Tahoe Basin along the crest, around 1.25-2.5 inches with around
0.75 - 1.25 inches in the Basin.
* Peak Snowfall Rates: For the Tahoe Basin, 1-1.5 inches per hour
rates will be possible this evening through midnight. For Mono
County, 1-2 inches per hour rates in the high Sierra are
forecast through early Saturday morning.
* Snow-Liquid Ratios: Snow ratios continue to be around 10-14:1 for
much of the system.
* Peak Ridge Level Wind Gusts: Peak wind gusts of 40-50 mph look to
be possible along the Eastern Sierra crest through Saturday
morning.
-078
&&
.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 5 PM PDT Sunday NVZ001-003.
Winter Storm Warning until 5 PM PDT Sunday NVZ002.
CA...Winter Weather Advisory until 5 PM PDT Sunday CAZ071.
Winter Storm Warning until 5 PM PDT Sunday CAZ072-073.
&&
$$
Area Forecast Discussion
National Weather Service Springfield MO
550 PM CDT Fri Mar 29 2024
.KEY MESSAGES...
- Windy conditions continue today with wind gusts of 40-50 mph
along and west of an Osceola to Cassville line. Gusts of 30-40
mph elsewhere across the Missouri Ozarks.
- Elevated fire weather conditions continue this afternoon.
- Low chances (15-30%) for showers/thunderstorms toward central
Missouri tonight and Saturday night.
- Monitoring the potential for strong to severe thunderstorms
Monday.
&&
.SHORT TERM /THROUGH SATURDAY/...
Issued at 1229 PM CDT Fri Mar 29 2024
A subtle upper-level ridge axis is currently centered over our
region with mid-level shortwave energy traversing the northern
Plains overtop a surface warm/stationary front in southern IA.
Despite the subtle ridging, upper-level flow is still largely
zonal with the core of the jet in line with the 37th parallel
(which includes our southern border). Strong westerly flow off
the Rockies with the help from modest left-exit jet stream
dynamics is forcing surface lee cyclogenesis across the central
Plains with a surface low progged over north-central KS.
Coinciding with the cyclogenesis is a tightening surface
pressure gradient largely parallel to the upper-level ridge
axis. As such, SSW`ly winds are increasing across our CWA,
notably with Springfield at 20-25 mph and gusts up to 35 mph and
Joplin at 25-35 mph with gusts up to 45 mph.
Windy conditions continue today with gusts of 30-50 mph:
The Wind Advisory is in effect until 7 PM CDT for counties along
and west of an Osceola to Cassville line. With BUFKit model
soundings outputting momentum transfers of 30-45 kts late this
afternoon at peak mixing, and observations in Joplin already
breaking the 40 mph threshold, periodic gusts of 50 mph are
possible, especially along and west of I-49. NBM has
probabilities of >50 mph at 10-30% with the max in Vernon/Barton
counties. Elsewhere outside the Wind Advisory, winds of 20-25
mph and gusts up to 30-40 mph are expected through the evening.
These winds should decrease once daytime mixing ceases after
sunset.
Elevated fire weather conditions continue this afternoon:
In tandem with the daytime mixing and gusty winds, relative
humidity values will decrease into the 35-40% range with some
localized pockets dropping below 35%. This will promote an
elevated fire risk in many areas of our CWA. That being said, none
of the HREF members drop RH values below 35% and the latest
Obs/CAMs comparisons show that dewpoints are slightly higher
than modeled which should keep RH from dropping any further than
that threshold. Nevertheless, with such gusty winds and still
appreciable low RHs this afternoon, any fire that does start
will be quick to spread, especially in areas with drier fuels.
Low chances (15-30%) for isolated showers/thunderstorms
tonight and Saturday night:
As subtle shortwave energy progresses across the Plains, the
surface low developing in KS will be kicked through northern MO
overnight. An attendant SW-NE oriented cold front will sag its
way right along our northern CWA counties by midnight tonight.
Ahead of this front, the RAP has shown potential for uncapped
elevated instability for parcels at 850 mb. Other CAMs breakout
some isolated to scattered light showers ahead of the front as
well. Thus, have introduced low chances (15-25%) for an isolated
shower or thunderstorm for our northern counties (generally
along and north of Hwy 54) between 10 PM and 4 AM. It should be
said that confidence is quite low for any appreciable
precipitation to occur in this region since the cold front will
weaken and stall as it reaches our CWA, but the potential is
there.
A surface deformation zone behind the exiting low and ahead of
newfound lee cyclogenesis will weaken and stall the cold front
early Saturday morning just within our northern CWA. An
approaching deep trough just off the coast of CA will initiate
lee cyclogenesis across the central Plains again, and the cold
front will transition to a warm front and lift back to the
north through the day Saturday before stalling across north-
central MO. This will keep highs in the lower to middle 70s
Saturday. The stalling of the warm front will be somewhere in
north-central MO which will once again introduce the chance
(20-30%) for elevated showers/thunderstorms across our northern
counties Saturday night. As with tonight`s chances, confidence
is low based on the position of the warm front and amount of
warm-air advection and isentropic forcing. Nevertheless, cloud
cover will be extensive with the warm front, keeping lows
Saturday night in the upper 50s.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 1229 PM CDT Fri Mar 29 2024
The trough centered over CA will progress to the east during the
day Sunday. Height rises will occur over our region ahead of the
wave along with SW`ly low-level flow advecting in warmer and
moister air. Highs Sunday will reach into the upper 70s with
lows in the lower 60s, reaching near record high minimum
territory.
Monitoring the potential for strong to severe thunderstorms Monday:
TL;DR:
SPC has us in a 30% chance for severe thunderstorms
Monday (this correlates to an Enhanced (3/5) risk). Ensembles
are agreeing on upper-level features, but diverge in near-
surface features which has implications on storm mode, timing,
and location of the best chance for severe weather.
Nevertheless, the broad and deep warm and moist sector with
overlapping strong deep-layer shear and sufficient instability
will bring the risk for severe weather somewhere in our CWA.
Further Details:
The trough will continue to push into the Central Plains
Monday, acquiring a positive tilt, with an elongated belt of
strong SW`ly flow across our region. Thanks to persistent S`ly
flow during the whole weekend, a rather spatially large and
vertically deep warm and moist airmass will be in place ahead of
the trough. Indeed, highs Monday are expected to be in the
upper 70s. A surface low is forecast to develop across KS below
some form of an embedded shortwave within the positively-tilted
longwave trough. This synoptic setup will favor the potential
for strong to severe thunderstorms across a large area Monday.
The SPC highlights a 30% chance for their Day 4 risk which
includes our CWA along with portions of OK/KS/AR. This
correlates to an Enhanced (3/5) risk.
Despite medium confidence in severe weather occuring within
this 30% risk outline, there are some uncertainties still in the
forecast. Clusters show that models are mostly in agreement in
the timing and placement of upper-level features, but they vary
widely in near-surface features. Particularly, 12Z GEFS has the
surface low location over central OK/KS, the 12Z EPS has it over
east KS/west MO, and the 12Z GEPS has it over east MO/west IL.
The slower GEFS solution would place the greatest threat to our
south and west, while the EPS solution would generally put the
greatest threat across our region. All models, however, depict
strong deep-layer shear and at least some instability (though
global models generally don`t handle instability well) across
much of the warm sector which would promote some form of severe
weather across the region no matter the solution.
Specifics on storm mode and hazards are also fuzzy this far out.
The slower GEFS solution also depicts a more potent embedded
shortwave which promotes greater backing of low-level winds,
increasing low-level shear and helicity. This would increase the
tornado threat. The EPS solution has largely unidirectional flow
throughout the column which would increase the initial hail
threat. Both solutions trend towards some sort of MCS
developing after the initial severe threat as upper-level flow
is parallel to a SW-NE oriented cold front that sweeps through
the region Monday night. Long story short, there is good
potential for strong to severe thunderstorms to occur. Both CIPS
analogs and CSU machine learning products back this confidence
as they continue to increase severe probabilities for our
region. However, the specifics on hazards, location, and timing
are still too far out to realize.
Further complicating things, global model ensembles are hinting
at ongoing rain/convection during the day Monday before the
main severe threat due to broad southwesterly warm, moist flow
and the phasing of a Pacific and Gulf moisture source. The
ESATs depict integrated vapor transport and PWAT values in the
97th-99th percentile for this time of year which would support
multiple rounds of at least moderate rainfall throughout the
event. The positive tilt of the longwave trough could also
promote training of storms before the system fully clears the
area. This brings concerns for localized flooding, but for the
moment, the WPC has our CWA in a marginal (1/5) risk. This will
be monitored as details continue to get worked out.
Brief cooldown mid-week:
After the cold front sweeps through Monday night, lows will
drop into the 40s and keep highs Tuesday and Wednesday in the
50s. There could be a sneaky frost Wednesday and Thursday
morning with current forecast lows in the mid-30s, but the NBM
25th drops as low as 32F. Additionally, the Extreme Forecast
Index has values >0.8 for minimum temperature for this
timeframe, hinting at cooler temperatures than what`s currently
in the forecast. Things should warm back up Thursday, though,
with highs back into the 60s.
In the longer range, the CPC depicts a good signal for above
normal temperatures and above normal precipitation for early
into mid-April.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 550 PM CDT Fri Mar 29 2024
High confidence in VFR conditions through this evening and
tonight. Mid to high level clouds move through this area this
evening with southerly wind gusts remaining around 20 to 25
knots. Wind gusts slowly taper off late this evening. LLWS out
of southwest at 40 to 45 knots through tonight. Scattered cloud
cover overnight, before additional cloud cover increases across
the area on Saturday morning. Periods of MVFR conditions develop
through early to mid morning with ceilings around 2500 to 3000
feet. Flight conditions look to return to VFR late in the TAF
period with winds becoming more southwesterly.
&&
.CLIMATE...
Issued at 240 PM CDT Thu Mar 28 2024
March 31:
KSGF: 62/1967
April 1:
KSGF: 62/1946
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...Wind Advisory until 7 PM CDT this evening for KSZ073-097-101.
MO...Wind Advisory until 7 PM CDT this evening for MOZ066-067-077-
078-088-089-093-094-101-102.
&&
$$
SHORT TERM...Price
LONG TERM...Price
AVIATION...Perez
CLIMATE...Schaumann
Area Forecast Discussion
National Weather Service Sacramento CA
210 PM PDT Fri Mar 29 2024
.Synopsis...
Active and impactful weather overtaking the area today, persists
through Saturday, and lingers into Sunday. Widespread rain,
moderate mountain snow, gusty southerly winds today, and isolated
thunderstorms on Saturday are all expected. Hazardous mountain
travel impacts are currently being observed and expected through
Sunday. Drier and warmer weather early to mid next week.
&&
.Discussion...
Afternoon radar analysis reveals Valley rain showers and mountain
snow showers overtaking the area. This activity is expected to
continue throughout the rest of the day and into the weekend.
Taking a look at GOES-18 Satellite this afternoon reveals a closed
low offshore with bands of precipitation moving northeast. Most
of the rainfall in the Valley so far has been relatively light,
with only 0.02" inches recorded at the downtown Sacramento site at
the time of this writing, but activity is expected to uptick in
intensity as we move through the afternoon and evening hours.
Gusty southerly winds will also be possible as we move through the
day, as a low to mid-level jet streak is beginning to move inland
this afternoon, as seen on SPC Mesoanalysis. Strongest wind gusts
are expected in the Delta and the southern Sacramento and
northern San Joaquin Valleys. Wind gusts of 40 to 45 mph are
anticipated in these areas.
The orientation and track of this system will keep most of the
impactful precipitation in the foothills and mountains, however
the Valley will see rainfall as the closed low continues to move
south and slightly offshore. The heaviest precipitation is still
expected to begin this afternoon and last into early Saturday
morning. Periods of scattered showers will remain possible for the
Valley throughout the day Saturday as well, as the closed low
continues it`s southerly track. A few isolated thunderstorms will
be possible tomorrow afternoon/evening, with the HRRR suggesting
roughly 100-200 J/kg of CAPE, mainly for locations south of I-80
and in the Delta. Any thunderstorms that do manifest tomorrow will
bring the risk of brief heavy rainfall, gusty winds, small hail,
and possible funnel clouds. Rainfall totals still remain on track
for around 0.50" to 1.00" inches for the Valley and foothills,
and 1-2" inches in the higher elevations.
Snowfall totals have remained relatively unchanged as well with
the afternoon forecast package. A slight decrease in anticipated
accumulations, with a general 1-2 feet expected for elevations
greater than 5000 feet, locally higher amounts at highest peaks.
Snow levels are still hovering around 3500-4500 for the remainder
of today and into Saturday afternoon, then rising to around
4500-5500 feet Saturday evening and into Sunday. A Winter Storm
Warning is in effect until 5PM PDT Sunday in the Sierra and
Coastal Range, including the mountains of Shasta County for
elevations above 4000 feet. Travel conditions have already
deteriorated along I-80 this afternoon with chain controls
active, and conditions are expected to remain hazardous through
the warning period. Be sure to check road conditions before
hitting the roads at quickmap.dot.ca.gov if travel is necessary.
Mountain snow showers may linger Sunday, mainly south of I-80 and
a few isolated rain showers will be possible across the southern
Sacramento Valley and northern San Joaquin Valley, with quiet and
dry weather expected elsewhere. As the closed low continues is
southerly track into Monday, winds will transition to a northerly
component with the NBM showing around a 20-40% chance of northerly
wind gusts of 30 mph or greater, mainly Monday morning along the
I-5 corridor, north of I-80. Upper level ridging will then build
in over the area as we transition into Monday evening, and will
help dry and warm things up for the area as we move into the
extended period.
&&
.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...
Dry weather continues through Wednesday as upper-level ridging
builds over Northern California, along with a continued warming
trend. High temperatures in the Valley will be in the mid to
upper 70s with the National Blend of Models (NBM) indicating a 30
to 60% chance of Valley highs greater than 80 degrees F north of
I-80. North of Anderson, CA, probabilities range 60 to 90% in the
Valley. Overall, high temperatures will be 5 to 10 degrees above
normal.
Gusty onshore winds return Wednesday ahead of a shortwave trough
moving through late-week. Heading into Thursday, cluster analysis
and ensemble guidance highlight a shortwave trough moving through
the area bringing chances for precipitation over northern Shasta
County and the mountains, as well as widespread cooler
temperatures. The National Blend of Models (NBM) indicates a
return of low-impact precipitation chances Thursday & Friday
focused mainly over the mountains and northern Shasta County. Widespread
cooler temperatures follow along with the return of gusty north
winds. The NBM is highlighting a 20 to 40% chance of gusts greater
than 30 mph on Thursday.
&&
.AVIATION...
Areas MVFR/IFR, local IFR, across interior NorCal next 24 hours as .
Gusty southerly winds 15-25 kts with gusts up to 35 kts in the
Valley and Delta, and up to 40 kts over higher terrain until 06Z
Saturday. Isolated thunderstorms possible vicinity of Delta until
04Z Saturday. Isolated thunderstorms in the Valley and foothills
after 15Z-18Z Saturday. Snow levels 3500-4500 feet.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 5 PM PDT Saturday for Mountains
Southwestern Shasta County to Western Colusa County-Shasta Lake
Area / Northern Shasta County.
Wind Advisory until 11 PM PDT this evening for Carquinez Strait
and Delta-Northern San Joaquin Valley-Southern Sacramento Valley.
Winter Storm Warning until 5 PM PDT Sunday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.
&&
$$