Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/31/24
Area Forecast Discussion
National Weather Service Columbia SC
1045 PM EDT Sat Mar 30 2024
.SYNOPSIS...
An area of strong high pressure and upper ridging keeps the
region dry through the weekend with above normal temperatures
into the early part of the week ahead. The next chance for
showers and thunderstorms arrives on Tuesday into Wednesday as
a cold front crosses the region. Cool, dry weather then follows
with temperatures near or below normal through the end of the
long term.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
High pressure remains in control through the overnight hours;
however, the center drifts south and eastward, causing winds to
shift to a more westerly direction late tonight. Some high
clouds associated with the low pressure system passing to our
north along with the relatively flat ridging continuing to build
over the region keeps overnight lows rather mild in the upper
40s to around 50.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Really quiet and beautiful weather is expected during this period,
with high confidence in the pattern evolution. Ridging will continue
to build through Monday evening, with surface high pressure settling
off to our southeast. As a broad area of low pressure develops
across the central Plains both days, a tight pressure gradient will
develop across the southeastern US. This should lead to both Sunday
and Monday seeing winds gusting 20+ mph during the afternoon. As a
result, expecting very warm temperatures and a gradual increase
in surface moisture as the week begins. Highs are likely to be
in the low to mid 80s both days. Some cumulus is likely Monday
afternoon as deeper moisture pushes in & surface dewpoints jump
up to near 60. Regardless, both days look great and guidance
supports this. Expect lows to moderate into the 60s as low level
moisture increases in quality and depth.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Tuesday and Tuesday night looks to be the most active weather of the
period. While our ridging takes place the prior two days, what will
be driving that is a complex upper trough that is currently pushing
into the California coast. This trough is forecast by most ensemble
and operational models to continue digging & translating into the
southwestern US by Monday morning. As this occurs, a northern stream
shortwave is forecast to dive into southeastern Canada, elongating
the trough axis and slowing the translation of the trough out of the
SW US. This is especially true as the strongest jet streak is
forecast to lie downstream of the trough axis by this point, which
should lift much of the energy northeastward across the central
Plains with some vorticity remaining across the SW. A strong
shortwave is then forecast to dig out of central Canada into the
northern portion of this elongated trough, phasing the northern &
southern streams and yielding a deep, closed low over the OH Valley
by Wednesday morning. How quickly this happens is up for significant
debate between various guidance, and this could have significant
impacts on our sensible weather impacts on Tuesday and Tuesday
night.
Ensemble guidance has been slowly trending a bit deeper and phasing
the mid and upper level troughs a bit quicker, similar to some
experimental Machine-Learning guidance from the ECMWF. This is
notable because if the quicker phasing solution does verify, there
is a higher likelihood that the approaching low and front on Tuesday
night could yield severe weather. For now, it looks somewhat
lackluster, with better chances likely to our west on Tuesday and
east on Wednesday. It is something to keep an eye on, though, as the
solution of a faster & deeper phasing over the central Plains could
be a problem. In any case, Tuesday looks quite warm again ahead of
the approaching front, with winds gusting over 20 mph out of the
southwest again. Expect highs in the mid to upper 80s. Showers and
thunderstorms are possible Tuesday night with this system, but
widespread long duration heavy rainfall looks unlikely at this point.
The front should push through on Tuesday night, with temps crashing
back below normal for the second half of the week. Look for highs in
the low to mid 60s and lows in the upper 30s and low 40s. Dry
weather is expected through next weekend behind the front.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
VFR expected through the TAF period.
Pressure ridge centered off the east coast of Florida with
southwest flow across the area. Southwest winds around 5 kts
through the early morning. VAD wind profile from KCAE radar
indicating west-southwest winds 1500-2000 ft 35-40 kts. RAP and
HRRR Guidance are suggesting wind shear through about 11z at
the CAE and CUB terminals. The low-level jet is weaker at other
terminals. The pressure gradient tightens again Sunday with weak
low moving east across VA. So expect southwest winds to
continue through the day with a few gusts around 20 knots mainly
after 18z. Some high level clouds will spread across the area
late tonight and increase Sunday afternoon. A few cumulus clouds
will be possible Sunday afternoon mainly near AGS/DNL.
EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
through Tuesday morning. Scattered to numerous showers and
thunderstorms ahead of a cold front late Tuesday into Wednesday
morning may lead to restrictions. Strong gusty winds possible
Wednesday afternoon behind the cold front.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
920 PM MDT Sat Mar 30 2024
.KEY MESSAGES...
- Another band of locally heavy snowfall is expected to develop
late this evening across Carbon, Albany, Converse, and
Niobrara counties. Expect significant variability in snow
totals over fairly small distances.
- A final round of snow remains on track for Sunday late
afternoon into Monday with banded snowfall expected over
portions of the High Plains. The exact location of more
significant impacts remains uncertain.
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 400 PM MDT Sat Mar 30 2024
A complex storm system continues to impact our area this afternoon,
with several components leading to a somewhat uncertain outcome.
Current satellite imagery shows the primary closed low responsible
for this weekend`s unsettled weather located off the central
California coast, with moisture streaming out ahead of it in
southwest flow aloft. Another vort-max has ejected out ahead of the
main trough and is moving into the area this afternoon, marked by
increased atmospheric water vapor on satellite imagery. While a
relative lull in precipitation is in place across the area, this
should begin to fill in again soon. The persistent diffluent flow
over the Rockies is beginning to produce pressure falls over east
central Colorado this afternoon, which should renew isentropic lift
in the 850-650 mb layer. This is causing showers to re-develop over
the High Plains this afternoon. This activity should continue
through about 3AM or so, and wouldn`t be surprised to see a few
rumbles of thunder embedded. Most of this activity will remain north
of I-80. Further north and west, the presence of the stalled frontal
boundary will complicate the forecast somewhat. Isentropic lift
combined with modest frontogenesis and the vicinity of the left exit
region of a 130-knot upper level jet streak is expected to lead to
another round of banded snowfall. Currently, this band is visible as
a train of shower activity around the Muddy Gap area towards Casper,
but HiRes model guidance generally shows this deteriorating and
being replaced by another band slightly further south that will then
shift north through Sunday morning. While earlier runs were in
pretty good agreement on a position generally from Rawlins to Lusk,
later HiRes model runs have abandoned this consensus. Thus, we still
don`t have the confidence to say exactly where this band will leave
its heaviest snow. However, with the expected southward jog of the
frontal boundary tonight, think that temperatures will run on the
cooler side north of this, leading to a faster change-over.
Therefore, decided to expand the Winter Weather Advisory to include
Converse and Niobrara counties. While advisory criteria snowfall is
not expected to cover the whole county, a narrow band is likely to
drop impactful accumulations of 3-6 inches somewhere in the zone.
Warning criteria amounts are likely to show up somewhere in Carbon
county, but don`t have the confidence for any upgrades due to the
uncertainty in the exact position of the banded snowfall.
This band of snow should move mostly north of the area by late
morning Sunday, putting another lull in place across the area. This
will be fairly short lived though. Cold air advection aloft in
advance of the main system will steepen lapse rates, leading to
several hundred J/kg of CAPE by Sunday afternoon. Showers should
develop by mid afternoon. This should be rain south and east of a
Cheyenne to Glendo to Alliance line, with snow mixing in outside of
this box. HiRes model guidance shows the surface frontal boundary
pushing back south tonight, and with northeast winds in place,
expect it to hold stronger on Sunday than it did today. Therefore,
cut temperatures down towards the low end of the NBM spread for the
US-20 corridor once again. The final phase of this system remains
extremely complex and highly uncertain. As the surface low
strengthens to our south, it will draw the front back to the south
Sunday afternoon and evening, leading to a rapid change-over back to
snow for the warmer areas mentioned above. A secondary 500-mb low
north of the main trough located over central Wyoming during this
period will complicate the typical wrap-around flow. Divergent
handling of the transfer of energy from this central WY low to the
developing Colorado low is resulting in a very large spread in
outcomes for snowfall Sunday night into Monday. The
ECMWF/GFS/RAP/HRRR solution keeps the developing low suppressed to
the south and keeps the old low stronger for longer. The result of
this is that effective wrap-around flow never really develops,
leaving us mostly dry Monday during the day and limiting QPF.
However, another solution shown by the NAM and several GEFS members
shows a stronger Colorado low closer to our area with potent wrap-
around moisture leaving fairly widespread snowfall across the area
through the day on Monday. These two solutions result in a very
large spread in potential snowfall outcomes for the area, with the
HRRR showing little to nothing south of the Pine Ridge, and the 3-km
NAM showing a widespread 4-8" over this area. With this little
confidence, decided not to do anything with headlines once again
(since this also may distract from the more immediate phase of this
system discussed above). Overall, leaning towards the drier scenario
with the official forecast at this time, but will need to monitor
model trends over the next 12-24 hours for the higher end
potential.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 400 PM MDT Sat Mar 30 2024
Looking at a speedy warm-up in the long term once the precipitation
associated with the Sunday/Monday system moves out. The upper-level
trough responsible for the precipitation will push eastward on
Tuesday, allowing a strong ridge to build in its place. Temperatures
will jump a solid 10 to 15 degrees on Tuesday compared to Monday`s
high. This will put highs around average for early April.
Temperatures continue to warm on Wednesday with the ridge axis
shifting over Wyoming. Highs will jump another 10 to 15 degrees with
temperatures in the 60s and low 70s east of the Laramie Range and
50s to the west. Last little push of warmth will happen on Thursday
as southerly winds advect warmer air into the CWA. This warmth will
continue into Friday with highs both days in the upper 60s and 70s
for the plains, and 50s and 60s out west. Currently, high
temperatures do not look to be in record warmth territory, however,
highs will be about 15 degrees above average. Expect mostly sunny
skies Tuesday through Thursday as subsidence under the ridge keeps
conditions dry. Heading into Friday evening, both the GFS and ECMWF
are in good agreement with a Pacific trough moving into Wyoming.
Although this is still a week out, this could be the CWA`s next
precipitation maker.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 911 PM MDT Sat Mar 30 2024
Southwest flow aloft will continue with weak disturbances in the
flow, and a stationary front draped across the area.
Wyoming TAFS...At Rawlins, ceilings will be near 2500 feet
until 15Z, with occasional visibilities near 1 mile in snow and
fog and ceilings near 500 feet until 10Z, then ceilings will
increase to 5000 feet after 15Z.
At Laramie, ceilings will range from 2500 to 5000 feet until
00Z, then lower to 1500 feet with visibility 2 miles in light
snow and fog. Visibilities will be near 5 miles in light rain
from 18Z to 00Z.
At Cheyenne, broken ceilings will be near 1200 feet until 08Z,
then ceilings will be near 4000 feet until 00Z, then lower to
1500 feet with visibilities near 2 miles in light snow and fog
after 00Z.
Nebraska TAFS...At Chadron and Alliance, ceilings will range
from 1500 to 2500 feet, with occasional visibilities from 2 to
3 miles in light rain, snow and fog.
At Scottsbluff and Sidney, ceilings will range from 1500 to
6000 feet, with occasional visibilities near 2 miles in fog
until 10Z, and then visibilities near 2 miles in light snow and
fog after 00Z.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until noon MDT Sunday for WYZ101-102.
Winter Weather Advisory until 9 AM MDT Sunday for WYZ103>105-
109>111-113.
Winter Storm Warning until 6 PM MDT Sunday for WYZ112-114.
NE...None.
&&
$$
SHORT TERM...MN
LONG TERM...SF
AVIATION...RUBIN
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
610 PM CDT Sat Mar 30 2024
.KEY MESSAGES...
- Multiple rounds of showers and storms are expected late
tonight through Tuesday morning. There is a marginal (level 1
of 5) risk of severe weather Sunday evening/night. A greater
severe risk is apparent on Monday, with all hazards possible,
mainly south of I-70.
- Storm total rainfall for the event is forecast to range from
0.75 to 2 inches, with the greatest totals east of U.S.
Highway 65.
- Cooler and drier weather will briefly return for the middle of
next week, with a quick warm-up to follow by the end of the
week.
&&
.DISCUSSION...
Issued at 213 PM CDT Sat Mar 30 2024
Temperatures have struggled to warm this afternoon, with light
northerly winds continuing to supply just enough cold advection
to inhibit more substantial warming. High clouds have also
impeded insolation a little bit, keeping highs a few degrees
below what they were expected to be at this time yesterday.
Meanwhile, there are signs the long-advertised warm
front/baroclinic zone is developing, with winds in Kansas
veering to a more east-northeast direction and southerly surface
flow nosing northward into far southwest Missouri. Meanwhile,
upper-air analysis from 12z reveals low-amplitude but broad
ridging encompassing much of the central U.S., with a digging
and potent trough near the West Coast. A midlevel zonally-
oriented jet streak stretched from the Intermountain West to
the Ohio Valley, with subtle vorticity maxima present on
moisture-channel imagery along this axis. Signs of surface
cyclogenesis in the lee of the Rockies were present, with
increasingly cyclonic surface flow in the central/southern Great
Plains.
Examination of the 00z ensemble data continues many of the same
themes from yesterday: the GEFS has a more potent leading vort
max as it lifts northeastward into the central Plains on Monday,
with the GEPS (CMCE) considerably more suppressed and delayed.
The EPS (ECMWF) remains in between the two extremes. So many of
the uncertainties in the forecast for early this coming week
remain, though the advent of convection-allowing models through
the weekend has permitted some improved confidence regarding
convective potential and evolution through Sunday night across
the CWA.
The first round of convection is expected to develop late tonight
as a low-level jet noses northeastward to the lower Missouri
Valley atop a tightening baroclinic zone stretching east-to-west
across Kansas and Missouri. Surface observations this afternoon
suggest a placement somewhere close to the Missouri River, with
showers and isolated storms developing near and north of the
boundary some time late tonight into the morning hours. HREF
timing is consistently around daybreak tomorrow, with initiation
in vicinity of (or just east/northeast of) the KC metro area.
Isentropic ascent will continue through much of the day as an
attendant perturbation progresses through the region, allowing
convection to persist for much of the day in a corridor from
southern Iowa and northern Missouri eastward. Used HREF-based
PoPs for the forecast through this period, with the best chances
(40-60 percent) generally along and north of U.S. Highway 36
and east of I-35.
HREF deterministic members generally agree on most of the
convection moving eastward from the CWA by afternoon, with the
warm sector edging northward and remaining unperturbed through
the diurnal cycle. By evening, another perturbation will
approach the Missouri Valley, with (some) convection-allowing
models initiating another round of storms around 00z. The
12z/18z HRRR initiate storms in a northeast-southwest broken
line in vicinity of I-35, for example. A look at various HREF
member model soundings indicate MLCAPE around 1000 J/kg and 0-6
km bulk shear approaching 60 kt in the pre-convective
environment (and 0-1 km SRH exceeding 100 J/kg). This near-storm
environment would be favorable for all hazards, though marginal
boundary-layer moisture would likely inhibit a more significant
tornado threat. However, convective initiation is not
guaranteed, with impacts of predecessor morning convection and
residual capping inhibiting factors. Should capping hold,
another round of elevated convection would be favored farther
north of the warm/quasi-stationary front Sunday night, with
marginally severe hail the primary hazard.
This leads to the question of how Sunday night`s convection
influences the severe potential on Monday. GFS-related guidance
continues to indicate a strong cyclone with widespread storms in
advance in much of the Missouri/Mississippi Valleys Sunday night
and Monday. Notably, however, the low track is farther south
than yesterday, which makes sense given (1) the strength of the
southern-stream dynamics associated with the system and (2) the
influence of antecedent precipitation shunting the warm sector
farther south with time. This would keep the highest severe
potential mostly south of the region. The CMC-related guidance
is slower, allowing for somewhat improved recovery in the
central Plains and perhaps better timing for more vigorous
convection toward the I-70 corridor in the afternoon/evening.
Of note, the NAM and NAM Nest solutions are qualitatively
similar to the slower/more suppressed guidance. At this stage,
it seems reasonable to infer that the greatest severe potential
is south of I-70 on Monday, with the northernmost extent
contingent upon the prior convective evolution Sunday night and
Monday morning.
No matter the model suite that verifies best, it appears
widespread convection is still in the cards Monday and Monday
night. Precipitation would be most welcome, with general QPF of
0.75 to 2 inches (lowest northwest and highest east) for this
event by Tuesday afternoon. Models have continued to slow the
system as it passes the region, and especially as it continues
to strengthen to our east. As such, PoPs linger through at least
Tuesday morning in most of the area, with precipitation moving
out of the far east CWA during the afternoon/evening.
Stout cold advection in the wake of the departing low should
bring a sharp cooldown for the middle of next week, with another
couple of nights of near-freezing to sub-freezing temperatures
to the area. Wednesday night looks to be the coldest night, with
a widespread freeze possible (probability of sub-freezing
temperatures in much of the area greater than 40 percent).
Otherwise, dry weather is expected for the rest of the week,
with warming conditions after the midweek cool spell. Highs by
Friday will be well above seasonal averages again, with upper
60s and lower 70s progged.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 610 PM CDT Sat Mar 30 2024
Lo conf TAF this cycle with the surface front in the VC of the
TAF sites til late in the TAF pd. VFR conds are expected to
prevail til 09Z-12Z when MVFR cigs are expected to develop at
the TAF sites. Cigs are then expected to further sink to IFR btn
12Z-14Z with the chc for lgt shra in the VC. Cigs are expected
to lift back to MVFR around 18Z before becmg VFR aft 20Z. Winds
to begin the pd will be out of the NE before becmg easterly aft
05Z. By 13Z winds will veer to the SE before becmg southerly aft
18Z. Winds speed will be generally btn 7-12kts however southerly
gusts to 20-25kts are expected at IXD and MKC aft 18Z-20Z.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.
&&
$$
DISCUSSION...CMS
AVIATION...73
Area Forecast Discussion
National Weather Service Green Bay WI
1048 PM CDT Sat Mar 30 2024
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- There is a 50-70% chance of light rain over central and east-
central Wisconsin from late Sunday afternoon through late Sunday
night. While some snow may mix in with the rain on Sunday night,
little to no accumulations are expected.
- A second round of wintry precip is expected to impact the
forecast area on Monday and Monday night. Rain and snow will
both be possible, although there is still uncertainty in the
track of the system.
- Quiet conditions and near to slightly above average temperatures
return mid-week.
&&
.DISCUSSION...
Issued at 328 PM CDT Sat Mar 30 2024
Short Term...Tonight and Sunday
The latest RAP analysis and satellite/radar imagery show an area
of low pressure moving into northeast Ohio while shortwave energy
is passing across the northern Great Lakes. Precip associated with
the shortwave will be exiting far northeast Wisconsin by issuance
time, but there is widespread low overcast upstream getting pushed
into northern Wisconsin via northwest winds. Some of this low
overcast is eroding on the southern flank as it runs into stronger
mixing where there is sunshine over southwest Wisconsin and
southeast Minnesota.
A cloudy high pressure system resides over the northern Plains,
while the next precip maker is currently over the central Rockies
with high cloud cover already spreading into the northern
Mississippi Valley ahead of it. Besides cloud cover, forecast
concerns mainly revolve around light precip on Sunday afternoon
from this system.
Clouds and Precip Chances: Weak high pressure will be building
into Wisconsin tonight. Think some clearing is possible over
central and north-central WI later this afternoon and into this
evening as thermal troughing is relatively flat. Not as confident
over north- central Wisconsin where clouds are relatively solid.
But if clouds erode, temps could reach their lows this evening
before mid and high clouds quickly return by late evening or
overnight.
As a warm front aloft moves into Iowa and northern Illinois on
Sunday, clouds are expected to thicken through the day. Fgen is
expected to increase with the tightening thermal gradient that
could lead to sufficient saturation for light precip after about
3-4 pm over central to east-central Wisconsin. Temperatures will
be warm enough for only rain to occur.
Temps: Even with a slackening pressure gradient and light winds,
counting on broken to overcast clouds to prop up temps and
prevent them from tanking tonight. Fresh snow cover makes this a
dicey proposition, so just went slightly below the NationalBlend
over north-central WI.
On Sunday, lowered temps a few degrees based on 925mb temps and
cloud cover. Highs will range from the low 40s over Vilas county
and near the Lakeshore to 50 degrees at the warm spots.
Long Term...Sunday Night Through Saturday
Main focus from this forecast period revolves around the potential
for wintry weather from Sunday night through Wednesday. Models
continue to show a southern trend with the precip chances during
this time. Therefore, chances for a rain/snow mix have shifted
further south, mainly along and south of Highway 29, while the north
should be precip-free.
Sunday night through Wednesday...F-gen driven moisture/precip
flowing along an upper-level zonal flow, spreading from NE to PA,
will attempt to lift into WI Sunday evening. While some models have
this precip band lifting into the southern portion of the forecast
area, others keep the precip south of the CWA due to the presence
of mid-level dry air dropping down from the north. Lowered rain
and snow chances and kept them along and south of Highway 29 as a
result, but did not want to go with a dry forecast across the
entire CWA given some CAMs indicate this precip band setting up in
this area. If this precip occurs, it would mainly be rain, but
snow could mix in along the northern edge. A lull in the precip is
anticipated from at least late Sunday night into Monday morning
ahead of an approaching Colorado Low. Plenty of uncertainty
remains with the timing and placement of this Colorado Low, as
there are issues with how the upper-level pattern will evolve with
the phasing of two troughs overhead. Models continue to keep the
bulk of the moisture associated with the Colorado Low to the south
of the region Monday into Monday night due to the continued
presence of mid-level dry air. But, there are still some ensemble
members indicating precip lifting into the southern portions of
the forecast area, mainly south of Highway 29. Kept chances for
rain and snow in these areas mainly during Monday afternoon and
evening. Uncertainty continues with where the Colorado Low will
track Monday night into Tuesday as this is when the upper-level
troughs finally phase together. If the low has a more
northeasterly track across northern IL, as some ensemble members
are depicting, there will be a higher chance for portions east-
central WI to see accumulating snow Monday night into Tuesday.
However, this solution is trending drier. If the track is further
south along the Ohio River Valley, like many other ensemble
members are depicting, the forecast area may remain precip-free.
Given the large model spread, kept the blend of models solution
during this time with chances for rain and snow staying along and
south of Highway 29. Late Tuesday into Wednesday, guidance
indicates a large upper-level closed low developing overhead,
causing the surface low to potentially retrograde over the eastern
Great Lakes region. Depending on how far west it retrogrades,
portions of eastern WI may see continued chances for rain and snow
during this time.
Rest of the extended...The upper-level closed low will gradually
shift eastward on Thursday and make way for an upper-level ridge
building towards the region. This ridging will set up over the
region through at least the first half of the weekend, keeping
conditions dry and allowing temperatures to rise above normal into
the 50s.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1048 PM CDT Sat Mar 30 2024
Widespread MVFR to low-end VFR stratus will prevail across the
region into Sunday. Some breaks may try to develop in the low
clouds late tonight into Sunday morning, though it is uncertain
where that will occur. The next chance for light rain (VFR visibility)
arrives at the very end of the TAF period, but only across the southern
portion of the forecast area. Besides ceilings, aviation impacts will
be low.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/Kruk
AVIATION.......JLA
Area Forecast Discussion
National Weather Service Grand Rapids MI
737 PM EDT Sat Mar 30 2024
.KEY MESSAGES...
- Rain Returns Sunday Afternoon
- Active Weather Monday Night Through Wednesday
&&
.UPDATE...
Issued at 450 PM EDT Sat Mar 30 2024
Based off of local webcams, the fog has thickened up along the
lakeshore. The HRRR suggests is could last for a few hours. I
updated to grids to reflect this and amended the nearshore and
zone forecasts.
&&
.DISCUSSION...
Issued at 330 PM EDT Sat Mar 30 2024
- Rain Returns Sunday Afternoon
Deeper moisture is peeling off to the east by this evening with
showers ending but low stratus clouds and possibly patchy drizzle
persisting for several hours this evening. The low clouds should
start to break up by sunrise as RH profiles show moisture becoming
shallow by 12Z although mid and high clouds remain.
The break in the rain is brief with the next wave moving east
along a very active baroclinic zone aligned from the Plains
through the Ohio Valley. Rain showers will be forming in an area
of isentropic ascent across southern and central Lower Michigan on
Sunday afternoon with increasing frontogenetic forcing Sunday
night.
There could be p-type issues across our northern zones Sunday
night as colder air filters south and GFS and NAM model soundings
show a mix with or change to snow can be expected before the
precip ends late Sunday night.
- Active Weather Monday Night Through Wednesday
Persistent upper-level zonal flow pattern finally begins to break
apart late Monday into Tuesday as several upper waves merge and
deepen over the Great Lakes. Given the complex interactions between
these upper waves there still remains a good deal of uncertainty on
forecast details at this point.
Low chance for precip (likely in the form of rain) Monday evening
across Southern Michigan as a stationary front sets up south of
the state line. Tuesday morning/afternoon sees better precip
chances as a surface low approaches from the southwest and travels
into the Ohio Valley. The flow will begin to shift northerly and
a deformation band will set up across Lower Michigan.
By Tuesday night to early Wednesday the upper level waves merge
and deepen into a cutoff low. In response, the surface low deepens
and retrogrades into Eastern Lower MI and Southern Ontario. Lower
Michigan becomes socked into the cold sector with 850mb temps
dropping towards -5C to -7C. At this point northerly winds will
turn gusty due to the deep surface low to the east and snow will
begin to mix in.
Important details such as the track of the low, timing, and
precipitation amounts remain uncertain, but there does seem to be
good ensemble consensus that some amount of accumulating snow will
be likely late Tuesday through Wednesday. Can`t rule out travel
impacts Wednesday due to snow, but as previously stated, forecast
details including snowfall amounts remain uncertain at this time.
The surface low departs east late Wednesday to early Thursday and
ridging moves in. Conditions gradually dry out Thursday with
temperatures on the upswing into the end of the week. Wednesday
should be the coldest day of the week with highs near 40 and by
Saturday we should be back into the mid 50s.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 737 PM EDT Sat Mar 30 2024
Large area of MVFR to IFR ceilings and visibility remains in place
this evening, as moist air below 3,000 feet is cooling while air
above 3,000 feet is drying. Guidance suggests some improvement in
conditions around Muskegon (MKG) to Mount Pleasant (MOP) late
tonight. However, expecting most TAF locations (particularly AZO-
BTL-JXN) to be predominantly IFR through late Sunday morning.
After 15 Z, better mixing of the lower atmosphere via daytime
heating may result in MVFR stratocumulus hanging on until later
in the afternoon.
&&
.MARINE...
Issued at 330 PM EDT Sat Mar 30 2024
North to northeast winds 10 to 20 knots might make for some chappy
waves around Big and Little Sable points, otherwise fairly calm
conditions through the weekend. Northeast winds will pick up on
Tuesday and Wednesday and waves will build greater than 4 feet
late Tuesday with gales possible by Wednesday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
UPDATE...MJS
DISCUSSION...Ostuno/Thielke
AVIATION...CAS
MARINE...Ostuno
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
946 PM EDT Sat Mar 30 2024
.SYNOPSIS...
High pressure remains over the area with warming temperatures
this weekend. The work week starts dry with a cold front crossing
the region by mid week, increasing shower and storm chances. Much
cooler and drier air returns for the latter half of next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 930 PM: Tonight, a surface low tracks into the northern
Mid-Atlantic with a trailing cold front pushing into the Central
Appalachians. A little moisture south of the front within westerly
flow may produce a stratocu deck along the northern NC/TN border
late tonight thanks to upslope forcing. A few sprinkles or drizzle
could result there, but a look at HRRR profiles near the mtn spine
reveals so little moisture that PoPs were reduced well below 10
percent. Temps have been running above the forecast so far this
evening at the sites where winds persist, but seeing how a few
sites have managed to go calm already and temps slipped there,
still feel good with min temps slightly on the lower side of
guidance. That still however suggests values on the order of 5 to
10 degrees above normal.
The front moves back northward Sunday as a weaker low pressure
center moves east along it. There will be another weak lee trough
over the area, but the overall pressure gradient will be less than
the previous few days. There my be some low end gusts by afternoon,
but overall winds will be lower than the previous few days as well.
There will be cirrus and possibly some stratocu developing with
warming, but there will still be quite a bit of sunshine. We already
were carrying PoPs below slight-chance, but with this update
lowered values even further, seeing continued lack of moisture
and weak subsidence inversion on prog soundings. Southwesterly
winds and rising heights/thicknesses will keep the warming trend
going. Highs will be around 15 degrees above normal, which may
threaten records (see Climate section below).
&&
.SHORT TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
As of 205 PM Saturday: Quiet conditions start off the short term
period, with a change coming by mid-week. The region remains under a
steady quasi-zonal flow aloft as a deepening low off the west coast
strengthens. To the south, an amplifying area of high pressure
slowly slides eastward as the trough out west deepens and moves
toward the central CONUS. Ahead of the system, guidance shows a
broad warm sector setting up across the southeast as PWATs steadily
increase due to the SW flow from the surface high off to the south.
Monday remains dry and quiet, but the weather starts to change come
Tuesday and Tuesday night. Over the central CONUS, guidance from
both the GFS and EURO indicate the upper low strengthens and lifts
toward the Midwest and Ohio Valley, leaving behind a very positively
tilted trough elongating toward the east. The low gets caught in a
semi blocking pattern up north and a strong FROPA aims to sweep
across the CWA Tuesday night into Wednesday. As for any severe
potential, guidance from the GFS and EURO develops a modest amount
of sbCAPE and muCAPE across the CWA Tuesday afternoon through the
evening. Modeled soundings show a mid-level inversion, keeping a cap
in place for any muCAPE to be taped into until later in the evening.
Another questionable and less favorable factor is the lack of
forcing from the upper jet, which continues to remain north of the
CWA. Current guidance keeps the sfc-3km shear around 40 to 45kts,
but parallel shear vectors. The misalignment of the forcing and
instability could keep storms strong, with a few severe, especially
over the mountains on Tuesday night. By Wednesday morning, FROPA
should continue to march across the CWA, wiping out moisture and
lowering temperatures to near climo. Additionally, with the tight
pressure gradient, expect winds to be gusty across the entire area
Wednesday.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
As of 215 PM Saturday: By the start of the extended forecast, an
omega blocking pattern starts to form across the CONUS. As the
strong low churns over the Ohio Valley, it reinforces NW flow aloft
Wednesday night through the remainder of the period. Colder and
drier air is expected to spill across the mountains, with a brief
stint of NW snow possible across the higher elevations of the NC
mountains on Wednesday night. By Thursday, guidance from the GFS
shows the drier air dominating and wiping out any remnant surface
moisture, cutting off the remaining few snowflakes fluttering around
the higher elevations. Little to no accumulations are expected at
this time. Aloft, as the ridge amplifies over the central CONUS, NW
flow persists through the end of the forecast period, with lee
troughing across the mountains decreasing. This should help bring
those gusty winds down, but the area should remain breezy. High
temperatures will start to feel rather cool compared to the start of
the week, with the drier and cooler Canadian air filtering in and
persisting through the period. Expect temps to dip down below climo
with much of the area east of the mountains to remain in the 60s.
Overnight temps will also dip into the 30s and low 40s, but outside
the mountains, guidance at this time keeps temps above freezing.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR under only FEW-SCT cirrus tonight at
the TAF terminals. Gusts still being reported at many obs sites
at issuance time, but think these are likely to cease within
the first couple hours of the TAF. Not expecting there will be
enough cloud cover to inhibit radiation tonight, but gradient
looks enough to keep winds from going calm, but mostly will fall
below 6 kt after midnight. They should remain from the SW except
at KAVL, which will stay NW into morning. LLWS criteria could be
met just downwind of mtn ridges but not likely enough at KAVL to
mention. Some low VFR cloud cover may develop near the TN border
tonight but not likely seen at any of the sites. On Sunday, winds
will pick up by late morning but are not expected to be as strong,
with gusts infrequent and likely remaining less than 20 kt. Cirrus
may increase during the afternoon.
Outlook: VFR thru Monday as dry high pressure lingers over
the region. Rain chances increase along with their associated
restrictions on Tuesday and Wednesday as a cold front moves in
from the west. Low clouds and scattered showers may linger over
the mountains Thursday with gusty NW wind most locations.
&&
.FIRE WEATHER...
Overall wind speeds and gusts will be lower on Sunday than we
have seen the past 2-3 days. Despite the continued warming trend,
increases in low level moisture on the southwesterly flow will
keep RH values above 25 percent. However, they will drop into the
upper 20s to around 30 percent range. All this should be enough to
preclude the need for a Fire Danger Statement. However, if temps
are warmer or dew points lower, then one may still be needed.
&&
.CLIMATE...
RECORDS FOR 03-31
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 81 1963 39 1906 62 1938 20 1964
KCLT 86 1986 36 1887 63 2022 21 1964
1998
1938
KGSP 86 1986 44 1915 62 1998 24 1964
RECORDS FOR 04-01
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 83 1974 40 1919 60 1927 20 1923
KCLT 86 1986 40 1887 64 1998 24 1923
KGSP 85 2010 45 1965 62 2016 24 1900
1986 1896
1910
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...CP
NEAR TERM...RWH/Wimberley
SHORT TERM...CP
LONG TERM...CP
AVIATION...Wimberley
FIRE WEATHER...RWH/Wimberley
CLIMATE...GSP
Area Forecast Discussion
National Weather Service Louisville KY
933 PM EDT Sat Mar 30 2024
...Forecast Update...
.KEY MESSAGES...
* Breezy today with chances for showers and thunderstorms late this
afternoon and evening. A strong storm or two cannot be ruled out,
but severe weather is not expected in general.
* Easter Sunday morning showers and some storms will move through
the region. Small hail and gusty winds are possible in stronger
storms.
* Stormy pattern early next week, especially Monday night and
Tuesday. Most likely timing for strong/severe storms would be
after midnight Monday night through the daytime hours Tuesday.
Confidence in the occurrence of storms is high, but confidence in
exact storm evolution and timing remains low at this time.
* Cold blustery weather arrives by Wednesday with the potential for
snow across portions of the area by late Wednesday night into
early Thursday morning. Little or no accumulation is expected.
&&
.UPDATE...
Issued at 933 PM EDT Sat Mar 30 2024
Storms have fired along the W-E oriented frontal boundary over the
past couple hours, and have mostly produced pea to half inch hail.
Earlier this evening, storms seemed to struggle around and above 20
K feet and AMDAR/RAP soundings showed a subtle inversion around that
height. However, data also showed that mid level inversion eroding
with time through the evening. More recently, we`ve seen a stronger
supercell develop over the IND/PAH border and is now moving into
Dubois county. This storm is marginally severe and in a favorable
environment for maintenance. So, will continue to track it as it
moves along and north of I-64. Mainly a hail threat, although can`t
rule out an isolated damaging wind gust given the dry low levels and
inverted V type of sounding near the surface. Should be a bit of a
stable layer setting up near the surface with sunset, but overall
think any stronger downburst winds might be able to punch through
with a good enough core drop.
Overall, expect convective activity to continue along the nearly
stationary boundary through the night. Most activity should be sub-
severe however can`t rule out a few stronger storms, especially if
that eroding mid level inversion yields some better elevated
instability values.
Previous Update...
Things are quiet across the CWA at the moment, although a couple of
key features to watch over the next 1 to 2 hours for possible
convective initiation. First off, visible satellite imagery shows
some notably more agitated/congested cumulus over far SW Illinois in
the vicinity of KMVN/KMDH/KSAR. This has been an area of focus on
latest runs of the HRRR as a convective initiation point generally
between the 22 and 00z time frame. We are seeing a slight uptick in
surface moisture convergence to around 5 g/kg on the latest SPC
mesoanalysis, so do think if we are going to see something soon, it
will be in this area. From there, convection would likely head
eastward as it moves down and roughly along the I-64 corridor into
the evening hours. If convection is able to fire, the environment
does appear to support some sustained updrafts as modest instability
combines with more than enough deep layer shear. We should become
more stable near the surface the deeper into the evening we get, so
the main threat would be small hail, and perhaps some gusty winds.
Stable layer should mitigate most of that, however the dry low
levels and a bit of an inverted V sounding in the low levels does
cause some concern for gustiness if you get a strong enough storm.
Overall, don`t expect anything severe and still not 100% sure we are
going to be able fire anything off for a while given a bit of an H7
inversion. Forecast is on track, just highlighting some areas to
watch over the next couple of hours.
&&
.SHORT TERM /THROUGH SUNDAY/...
Issued at 258 PM EDT Sat Mar 30 2024
This afternoon and evening... The low pressure system and associated
fronts currently located over southern Lake Michigan will continue
to propagate southeast. As the cold front approaches the region, it
will slow and eventually stall into a stationary front over the Ohio
River. This front, coupled with increased moisture into the region
should lead to enough instability to initiate convection around 22-
23Z. With steep lapse rates, could see some gusty winds and small
hail with convection. With sunset, instability will rapidly diminish
and showers and storms will dissipate.
Tonight and Sunday... The quasi-stationary front will meander near
the Ohio River in the overnight and morning hours. Another wave of
showers and some embedded storms are possible as a 35-40kt LLJ moves
through the region and continuous moisture is pumped into the low
levels. Showers and storms are most likely along the frontal
boundary in the I-64 corridor beginning at about 8Z and lasting
until mid-morning. Weak, but sufficient instability, 35-45kts of
effective bulk shear, and steep mid-level lapse rates could lead to
a hail threat. Low temperatures will be in the 50s, with a gradient
of low 50s in the north and warmer to the south.
In the afternoon, the stationary front will begin to lift north and
the region will be deeper within the warm sector. This will allow a
stronger lid to develop and diminish chances for convection. Could
see some showers and isolated storms over southern Indiana closer to
the boundary. Continued southwesterly flow and warm air advection
will bring high temperatures into the mid-upper 70s and even
touching 80 in some areas.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Issued at 258 PM EDT Sat Mar 30 2024
Warm front will keep most of Sunday night`s convection focused north
of our area, more toward the I-74 corridor. Can`t rule out a few
showers or storms across some of our southern Indiana or northern
Bluegrass counties, so we`ll keep a 20-30 POP there during the early
evening. Frontal position a bit uncertain as it could wave north and
south a couple times as sfc lows ride east along the front.
Monday the warm front stays just north of southern Indiana/central
Kentucky. However, as the day progresses the column will moisten and
the cap will weaken as low pressure crossing Kansas and a Bermuda
high pump Gulf moisture northward. H5 speed max will also be
approaching from the west by late afternoon, and its interaction
with the front will spark convection mainly across eastern
MO/central IL/west-central IN. AS a result POPs really ramp up over
our southern Indiana counties late in the day as storms approach.
The strongest sfc waves eject out of SE Kansas/NE Oklahoma Monday
night, with the first crossing southern Indiana just before daybreak
Tuesday and the other during the afternoon. Convection will fire
near or just NW of the Ozarks late Monday, and approach southern
Indiana and central Kentucky in the pre-dawn hours of Tuesday as an
increasingly messy squall line. Even with weakening convection, all
severe modes are still on the table with strong winds just off the
surface, strong shear, and moderate instability. Proximity to the
warm front and backing of winds with sfc waves could enhance
helicity enough to support spin-up tornadoes, and that threat lines
up well with SPC`s Day 2 Slight over southern Indiana. Severre wx
chances on Tuesday are dependent on the timing of cold fropa, which
could shunt the better chances more into eastern Kentucky if the
front crosses our area during the diurnal instability minimum.
Flood potential will be limited by fairly quick storm motion, but
there`s the chance for enough repeated convective rainfall to
support a Marginal flash flood risk over southern Indiana and north
of I-64 in Kentucky. At this time that looks like a short-fuse,
flashy threat rather than any mainstem river flooding.
Winds outside of thunderstorms will increase considerably as well,
with 30-40 mph gusts likely late Monday night and most of Tuesday.
Strong cold advection sets up behind the front Tuesday evening, and
a deep closed upper low drops through the Great Lakes. Wednesday
looks showery and unseasonably cool under a strong cold pool. Max
temps will struggle to get out of the 40s, and as we cool well into
the 30s Wed night, any lingering precip could change over to snow
with fairly steep low-level lapse rates. At this point it doesn`t
look like anything more impactful than a dusting of accumulation on
grassy or elevated surfaces.
Upper trof finally lifts out Thursday to begin a moderating trend,
which could initially be slow as just enough cyclonic curvature
remains that clouds could be stubborn. Better chance for clearing
will be Friday as heights rise and the sfc high drifts into the
Mississippi Valley.
&&
.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 736 PM EDT Sat Mar 30 2024
Showers and a few storms have developed along a W to E oriented
frontal boundary across the area. Given the nearly stationary aspect
of this front, it could bring a prolonged threat of a few showers
and storms to all of the TAF sites along and near the I-64 corridor
through mid to late morning on Sunday. After that, it is expected to
lift north as a warm front, temporarily taking the threat of showers
and storms away. In addition to the shower and storm threat, also
expect some lowering ceilings after Midnight at all four I-64 TAF
sites (HNB/SDF/LEX/ RGA). The ceilings could settle on either side
of the 2K foot mark, but fully expect some MVFR either way. Some
minor vis restrictions could also occur in this corridor, although
lesser confidence in that scenario.
Surface winds will be light and variable while the front hangs over
the area, and then take on a SSW component through the afternoon on
Sunday as the warm front lifts north. BWG will stay south of all of
this activity, and only expect some mid level clouds, but continued
VFR through this forecast cycle.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...BJS
SHORT TERM...SRM
LONG TERM...RAS
AVIATION...BJS
Area Forecast Discussion
National Weather Service Marquette MI
1055 PM EDT Sat Mar 30 2024
.KEY MESSAGES...
- Quiet weather through tonight.
- Snow from developing system in the Great Lakes late Monday to Wednesday
appears like it will stay mostly south and east of the
forecast area.
- Temperatures will trend to above normal by next weekend.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 223 PM EDT Sat Mar 30 2024
Upper air pattern consists of a 500 mb closed low off the CA coast,
a shortwave in Saskatchewan, and a shortwave in the upper Great
Lakes. The shortwave will be moving out of the upper Great Lakes
while the next shortwave moves towards Lake Winnipeg by this
evening. This next shortwave moves into western Ontario by 12z Sun.
Snow continues to wind down across the area as the narrow band of
snow, heavy at times moved through. The snow has been moving out
quicker than what models are depicting, so have been playing catch
up with this all day. A quick 1-3 inches of snow fell with that band
in about an hour or two. This will have moved out late this
afternoon and dry, but mostly cloudy weather will set in. Overall,
did not make too many changes to the going forecast.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 304 PM EDT Sat Mar 30 2024
There`s remarkable agreement in the overall structure of the
forthcoming pattern across North America when considering the 0z and
12z deterministic guidance packages. The Canadian, GFS, and Euro all
highlight the near zonal flow across the Northern Plains and deep
troughing moving into the West Coast becoming split flow between a
broad trough over Hudson Bay, a series of shortwaves moving through
Manitoba/Ontario, and the deep trough ejecting out of the Southern
Plains early next week. From there, each also narrows in on the
pattern amplifying in response to the phasing process beginning
between a shortwave moving into the Northern Plains and a southern
stream shortwave lifting through the middle Mississippi River
Valley, resulting in cyclogensis over the Lower Great Lakes region.
By Wednesday night, this transitions to an Omega pattern, with the
resultant closed low making its way into New England, ridging moving
out of the Rockies, and another trough moving into the West Coast. A
look at their respective ensemble systems show the same agreement,
but also include individual members varying in space, time, and
magnitude of key features within this pattern. Narrowing in though,
does support very good agreement and thus, high confidence in this
forecast through at least Tuesday when the surface low begins
deepening somewhere between the Ohio River Valley and Lake Huron.
The forecast on Sunday will be marked by mostly dry conditions and
highs in the 40s, except some 30s in the Keweenaw. A weak surface
trough will drop southeast through Ontario, scraping the northern
portions of Lake Superior through the day, which will keep skies
cloudy. Most models maintain a dry layer between 4-8k feet through
the day, but some like the HRRR and RAP resolve precip by afternoon
across the east thanks to right entrance/left exit jet dynamics and
seeder-feeder action. High pressure builds in behind this shortwave,
moving through Ontario overnight and Monday. To the southwest, a
robust shortwave will begin to lift out of the Southern Rockies,
then gradually shift through the Central Plains by afternoon.
Overrunning, isentropically forced precip will be possible across
much of middle America Sunday night and Monday in response to this
unfolding, but the high pressure shifting through Ontario will fight
to keep our region dry, eliminating precip chances across the
forecast area for all but the far south-central.
Through Tuesday, the same will take place, but a shortwave dropping
out of the Northern Plains in the afternoon will begin taking on a
weakly negative tilt by evening, amplifying the surface low near the
Ohio/Indiana stateline. Uncertainty in the forecast starts here, as
the resultant deepening surface low and occlusion Tuesday night and
Wednesday will occur somewhere between Lake Huron, Ohio, and Lake
Erie. The more northern options could result in some cyclonic,
upslope enhanced precip downwind of Lake Superior and/or synoptic
precip near Lake Michigan and eastern Upper Michigan. Probability
for this solution is currently low (25% or less), but can`t be ruled
out at this point. Beyond this, high pressure and mid-upper level
ridging stretch across central CONUS/North America Friday and into
the Great Lakes this weekend, as the closed low shifts east into New
England and a deep trough presses into the West Coast. This should
support a dry and warming trend for us Friday and into the weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 1055 PM EDT Sat Mar 30 2024
Amendment: KSAW and KCMX have actually been worse than expected for
the past few hours. While they should see an overall improving trend
throughout the next several hours, it may take longer for these
terminals to improve than previously forecasted.
Low-level cloud cover stays over the area tonight into Sunday as a
weak low continues leaving to our east and a second shortwave low
moves towards southern Lake Michigan. Ultimately, we should be
seeing a very slow, but gradual, improvement across the TAF sites
over the next 24 hours; we could see conditions improve to VFR late
across the TAF sites, particularly at KIWD and KCMX.
&&
.MARINE...
Issued at 304 PM EDT Sat Mar 30 2024
A weak inverted trough and another surface trough will move through
the Upper Great Lakes this afternoon and again Sunday, but these
will result in only wind direction changes. Winds should be light
and under 20kts through at least late Tuesday, when increasing
pressure gradient results in increasing winds to near 30-35kts out
of the northeast to north. The culprit behind this is a deepening
surface low late Tuesday through Wednesday between the Thumb and
Lake Erie. The EC ensemble system suggests 20% chance or less of
gales in this period. If the system ends up tracking near the Thumb,
these probabilities should increase. As the low weakens and moves
east late week, northerly winds then fall back below 20 knots on
Thursday, continuing through the rest of the work week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...07
LONG TERM...JTP
AVIATION...TAP
MARINE...JTP
Area Forecast Discussion
National Weather Service Reno NV
330 PM PDT Sat Mar 30 2024
.SYNOPSIS...
The region continues to see bouts of mountain snow and a valley
rain-snow mix going through the rest of the holiday weekend.
Impacts to travel will persist especially over the Sierra Mountain
Passes as a result. Drier and warmer conditions are expected to
start the work week following this weekend`s precipitation. By
the later half of next week, another active weather system looks
to impact the region bringing increased precipitation chances and
cooler temperatures.
&&
.DISCUSSION...
Rest of Today through Sunday:
The latest RAP analysis shows an upper air low currently spinning
about 150-200 miles west of central CA coast and causing a generally
southerly flow over the CWA. The latest forecast model runs then
project this low to moving south-southeast along the CA coast
through the rest of the day and into the night. On Sunday, models
forecast the low to open up more into a trough during the morning
hours over southern CA and turn the CWA`s upper air flow more north-
northeasterly through the rest of the day with trough continuing to
progress eastward a bit. With this occurring above, periods of
mountain snow and a valley rain/snow mix look to be on tap for the
region through the rest of today and into tomorrow before tapering
off to the southeast during Sunday evening. The latest additional
forecast snowfall totals look to range about 5-15 inches in the
Sierra Mountains with locally higher amounts possible while portions
of the valleys may see up a trace up to around 4 inches possible.
Models do not appear to be doing well reconciling snow levels which
has been making the totals difficult to forecast. Currently, snow
levels look to be down 4000-4500 ft during the night for the
southern half of the region with portions of Mono County seeing
levels almost down to 3500 ft. There is also the potential for some
snowband development tonight which may allow for some greater
snowfall totals in the valleys. The 12Z run of HREF probability
tracker looks to target the areas around Lake Tahoe beginning this
late afternoon and going until about midnight. Will continue to keep
an eye on conditions should any additional products need to be
issued or totals need to be updated. Forecast model soundings also
show some convective potential, so there may be a rumble of thunder
coming from a passing shower though severe thunderstorms are not
anticipated at all. Hazardous traveling conditions continue to be
expected going through the rest of today and into Sunday morning
especially for the Sierra Mountain region with slick roads and
lower visibilities due to the snowfall. If you must travel during
the remainder of the holiday weekend, it is advised to take
caution and prepare for these conditions. For the latest updates
on the Winter Storm Warning and Winter Weather Advisory products
as well as forecast additional snow totals, please check out
www.weather.gov/rev/winter.
Monday through Wednesday Morning:
Forecast guidance shows a positively tilted Pacific upper air ridge
moving over the west coast by Monday morning causing the CWA to
take a northeasterly flow as the aforementioned trough departs to
the east. This western ridge is expected to progress eastward
through Monday as well as Tuesday with the axis of the ridge
passing over the CWA by the late morning hours of Tuesday. By
Wednesday morning, the CWA`s upper air flow starts to turn more
west-southwesterly as an upper air trough moves in behind the
ridge. This setup causes a surface high to move into the region on
Monday that starts to move out late Wednesday morning. Mostly
sunny skies, dry conditions, as well as warming trend are all in
the forecast for the beginning of the week.
Wednesday Afternoon into the Weekend:
By late Wednesday afternoon, models have the CWA turning
southwesterly with the forward portion of the trough making its way
over the CWA as the trough digs down across the Pacific coast
through the rest of the day. On Thursday, models appear to agree
with having an upper air low developing within the base of the
trough though the GFS places it off the coast of northern CA while
the ECMWF has it more to the north off the coast of OR/WA. The
uncertainty between models just grows going forward because of this
displacement discrepancy as the GFS tracks the low moving east-
southeastward across the southern portion of the CWA on Friday and
then into the Rockies on Saturday. The ECMWF on the other hand has a
somewhat slower progression with the low making its way over the CWA
on Friday night and out east into ID/UT/WY on Saturday. Details
still are pretty fuzzy on this upcoming system as a result, but
there does look to be the return of precipitation chances to the
region late Wednesday through Friday with conditions drying out
again on Saturday at this time. Also, there are signals for breezy
to gusty winds to return on late Wednesday and Thursday following a
cold front passage. Will continue to monitor this late week system
for better model agreement going forward.
-078
&&
.AVIATION...
Periods of mountain snow and valley rain/snow mix expect to continue
throughout the region care of the low pressure off the coast of CA
going through the rest of today and into tomorrow. With this
precipitation in the area, MVFR ceilings are in the forecast for the
Sierra terminals while models show the lower elevation terminals
look to see IFR-MVFR ceilings with lower ceilings mostly occurring
this evening and going into the morning. There is concern that
visibilities will drop IFR to LIFR at times this evening too as
there is the potential for some convectively driven showers passing
most of the terminals (the exception being KMMH) that will increase
increase precipitation intensity. This looks to be a little harder
to pinpoint exact timing, but the HREF signals band potential
increasing after 22-23Z until around 06-07Z. Will continue to
monitor conditions and amend TAFs as needed, but there is pretty
good confidence for at least sub-VFR conditions for today going into
tomorrow.
-078
&&
.AVALANCHE...
An impactful weather system continues to affect the region
through Sunday, with heaviest snowfall expected tonight/Sunday
morning.
* Additional liquid totals (SWE) through Sunday: For Mono county
above 7000 feet, 0.30-0.75 inches. For the Tahoe Basin, generally
0.50-1.25 inches with heaviest amounts along the crest.
* Additional snowfall: around 4-10 inches south of Sonora Pass and
around 8-16 inches north of Sonora Pass through Sunday.
* Peak Snowfall Rates: The latest run of the HREF shows snowfall
rates still generally between 1-1.5 inches per hour, but there is
potential for up to around 2 inches per hour particularly in the
Tahoe Basin during this evening and overnight.
* Snow-Liquid Ratios: Continues to be generally around 10-14:1 for
the rest of the system.
* Winds: winds look to pick up over the night a little bit out of
the west-southwest around 30-40 mph in the higher locations.
-078
&&
.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 11 AM PDT Sunday NVZ001-003.
Winter Storm Warning until 11 AM PDT Sunday NVZ002.
CA...Winter Weather Advisory until 11 AM PDT Sunday CAZ071.
Winter Storm Warning until 11 AM PDT Sunday CAZ072-073.
&&
$$
Area Forecast Discussion
National Weather Service Springfield MO
617 PM CDT Sat Mar 30 2024
.KEY MESSAGES...
- Temperatures 10-15 degrees above normal through Monday.
- Low chances (20-40%) for showers/thunderstorms toward central
Missouri tonight and Sunday night.
- Increasing potential for severe thunderstorms Monday. The
Storm Prediction Center has issued a Slight (2/5) to Enhanced
(3/5) risk for our area.
- Conditional flooding threat Monday. The Weather Prediction
Center has issued a Slight (2/4) risk for portions of the
area.
- Brief cooldown for the middle of next week.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 135 PM CDT Sat Mar 30 2024
Synoptic Pattern and Current Conditions: Water vapor imagery and
upper air analysis showed the next storm system spinning off the
California coast. Zonal flow aloft with weak mid level ridging
extended east through the central US. A surface front was
located from northern Oklahoma, through areas just north of
Joplin, to Lake of the Ozarks and then northeast into Illinois.
An area of clouds was located near this front and latest
visible imagery suggests that the front is in the process of
stalling as surface winds remain southwest to westerly. Low
level moisture continues to get drawn up from the south with
low to mid 50 dews across the area. Temps varied from the low
60s north of the front to the low 70s across south central
Missouri.
Tonight: Surface low pressure will begin to deepen across the
lee of the Rockies. A 40kt low level jet looks to become
established across Texas, western Oklahoma and into central
Kansas overnight with some veering into southwest Missouri. The
stationary front across the area will begin lifting north.
Latest HREF mean MU CAPE along with the RAP MU CAPE/CIN plots
shows an area of 500-1000j/kg of MU CAPE with an eroding cap
after 9pm for areas north of I-44. This is mainly lifting
parcels freely from 800-850mb. Large scale lift looks weak
given the mid level height rises therefore coverage looks low as
shown in high res paint ball plots. A consensus of short term
models and the NBM shows a 20-40% chance of showers and storms
north of I-44 tonight. Surface winds will begin to increase out
of the south and combined with clouds will keep temps mild again
with lows in the upper 50s to lower 60s.
Sunday through Sunday night: The area looks to be well into the
warm sector with the warm front located along or just north of
I-70. The latest HREF does indicate a substantial amount of mid
to high clouds during the day as the flow becomes more
southwesterly. Current NBM temperature forecasts suggest
widespread high temps in the upper 70s to near 80. However 850mb
temps look to reach the 15-18C range therefore if any clearing
occurs then temps could soar several degrees higher. Southerly
winds will be gusty with 25-30mph gusts likely during the
afternoon, especially west of Springfield. No precip is
expected during the day.
By Sunday night, a 40kt low level jet will overspread the area
and impinge upon the front north of the area. Showers and
thunderstorms look more likely north of the area however a few
storms could creep into areas of Benton and Morgan counties. Low
temperatures look to remain even warmer than the previous night
with many areas only dropping into the lower to middle 60s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 135 PM CDT Sat Mar 30 2024
Monday through Tuesday System: A deep upper level trough will
move into the plains with southwest flow aloft continuing to
pump moisture into the area on Monday. Surface low pressure
looks to develop across northern Oklahoma with the front
stretching northeast into central Missouri. Large scale lift
will spread into the area through the day with a 140kt upper
level jet nosing into the area. Ensembles continue to suggest
the potential for substantial clouds and precip during the day
ahead of the front. Temperatures will be tricky for Monday as
clouds/precip could keep temps in the lower 70s however breaks
in the clouds could push temps higher.
Clouds/precip will have an impact on the amount of instability
available for when the front pushes into the area Monday
evening. Wind shear looks to be more than favorable for
organized/severe storms (50-60kts 0-6km bulk wind differences)
however the amount of instability is in question. Mid level
lapse rates continue to look poor (5-6C/KM) given the amount of
clouds and ongoing precip. Latest NBM data suggests 80-90%
chances for >500j/kg of surface based CAPE across the area
however chances for >1000j/kg drop off substantially therefore
this could be a high shear/low CAPE event which often times
still produces severe events across the area. These types of
events typically have a "messier" component to them given the
potential for mixed modes and the formation of storm clusters. We
should begin to get a better handle on the instability as we
get closer and into the high res model range. Given the amount
of wind shear available, large hail, damaging winds and
tornadoes will all be of concern with this system and the SPC
outlook for Monday covers these threats in even more detail.
Continue to monitor updates as we get closer to Monday.
The other concern with this system will be flooding. The WPC
excessive rainfall outlook still shows a slight risk for
flooding, especially along the frontal boundary. Forecast PW
values look to be in the 1-1.5in range and given the
orientation of the system and front would support training of
showers and storms. Latest NBM probs of 1 inch of rain or
greater are currently in the 40-60% range across the area.
Tuesday through Friday: Lingering clouds and light precip look
to linger on Tuesday which will keep high temps in the 50s. The
upper level low will slowly shift into the Ohio River Valley
Wednesday with continued cool and dry northerly winds. High
pressure builds on Thursday morning which could bring low temps
down into the lower 30s. This could produce frost and will need
to monitor temperature trends. Ensembles then suggest mid level
ridging building into the central US late in the week which
will likely lead to a sizable warmup by Friday.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 617 PM CDT Sat Mar 30 2024
Surface low pressure will build across the plains tonight and
Sunday. Winds will be light early this evening and will become
more southerly tonight with gusty southerly winds expected on
Sunday.
Isolated showers and storms will be possible late this evening
into tonight, but the better chances will be just north of the
TAF sites across central Missouri.
&&
.CLIMATE...
Issued at 135 PM CDT Sat Mar 30 2024
Record High Minimum Temperatures:
March 31:
KSGF: 62/1967
April 1:
KSGF: 62/1946
Record Precipitation:
April 1:
KVIH: 0.88/1945
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...None.
MO...None.
&&
$$
SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Wise
CLIMATE...Burchfield
Area Forecast Discussion
National Weather Service Topeka KS
650 PM CDT Sat Mar 30 2024
.KEY MESSAGES...
- There is a 20 to 30 percent chance of thunderstorms Sunday
morning across northeast Kansas. If storms develop, there may
be some large hail.
- A few severe storms may be possible across east central KS
Saturday evening with 60 MPH wind gusts and large hail
possible if storms develop.
- Thunderstorms will redevelop early Monday morning and continue
into the afternoon hours, ( A 30 to 50 percent chance).
Severe thunderstorms will be possible across east central KS,
with large hail as the primary hazard.
&&
.DISCUSSION...
Issued at 233 PM CDT Sat Mar 30 2024
Early this afternoon, an amplified upper trough was moving southeast
onto the central CA coastline. A broad upper level southern stream
jet has shifted northeast across Plains. An upper level trough was
existing off the New England coast line.
At the surface, a cold front was pushing southeast across OK and the
TX PNHDL. Weak low-level CAA was causing Temperatures to be a bit
cooler early this afternoon, with lower 60s across the southeast
counties to lower 50s along the NE border.
Tonight through Sunday night:
The upper level trough centered along the central CA coast will dig
southeast across southern CA into northwest Mexico and southwest AZ
by 12Z MON. A northern stream H5 trough will dig southeast across
western Canada into south central Canada and the upper Midwest.
Southwesterly H5 flow across the Plains will increase to near 50 KTS
and a lee surface trough will deepen across the central and southern
high Plains. The surface front across OK will stall out Tonight
across south central OK while southerly 850mb winds transport richer
moisture northward across the southern and central Plains. The front
across OK will move back north as a warm front. Isentropic lift
north of the front will cause showers and thunderstorms to develop
late Tonight across east central and northeast KS. As the surface
warm front shifts northward across the CWA during the mid morning
and afternoon hours, the stronger isentropic lift will shift
northeast of the CWA and there may be a break in the showers and
thunderstorms during the mid and late afternoon hours. A few of the
CAMs show the cap breaking along the warm front across west central
MO. These surface based storms may be supercells with MLCAPES of
1200-2200J/KG and 50 to 60 KTS of effective shear. The forecast
hodographs show low-level curvature, which would provide for stream-
wise horizontal vorticity ingestion into any robust updraft.
When the streamwise horizontal vorticity is tilted vertically by
the updraft, stronger low-level mesocyclone may develop which
could lead to tornadogenesis. The only question would be if the
the strengthening EML may create a stronger CAP across west-
central MO and east central/northeast KS along the surface warm
front. The severe threat would be conditional but the 18Z HRRR
did show surface based storms developing after 00Z MON,
southeast of KC and back building west-southwest into southern
Douglas and Franklin Counties. So, this possibility for severe
thunderstorms will need to be watched across portions of east
central KS Sunday evening.
Sunday night, the transport of richer moisture northward along with
embedded perturbations rounding the main upper trough across the
southwestern US, and with a strengthening LLJ will provide a
chance for mainly elevated thunderstorms. MUCAPEs will be in
the 1000-1500 J/KG range and there will be 60 to 70 KTS of
effective shear. Therefore, if elevated storms develop they
could produce strong mid level mesocyclones which could produce
large hail. The severe threat will last into Monday morning.
Monday through Tuesday:
A section of the southwestern H5 trough will lift northeast into the
Plains Monday afternoon. Strong low-level CAA will push the
stationary boundary southeast across the CWA during the late morning
and early afternoon hours. 850mb winds begin to veer across the
southern Plains ahead of the southeast moving cold front and dryline
across OK. A line of severe storms will develop along the front
across central MO, extending southwest across southeast KS and then
south-southwestward across central OK. For a few hours these surface
based storms may be scattered discrete supercells. A surface
low will deepen across northeast OK and track northeast across
south central MO. The best potential for tornadic supercells
will be along the the warm front across south central MO into
central IL where the low-level shear would be more favorable.
Supercells that develop along the front across southeast KS into
northeast and central OK may produce large hail and damaging
wind gust. There may be a window of strong elevated
thunderstorms behind the cold front across east central KS.
These storms may develop intense mid level mesocyclones and may
produce large hail southeast of the KS turnpike Sunday
afternoon.
The strong CAA behind the front may drop 850mb and surface
temperature enough for some snow to mix in with the rain or turn
briefly to a wet snow before the precipitation ends Tuesday
morning across the western half of the CWA.
Tuesday night through Wednesday night. The main H5 trough will phase
with an amplified upper trough digging southeast out of central
Canada into the upper Midwest. The resulting amplified closed upper
low will shift slowly southeast across the southern Great Lakes.
This will keep the Plains under northwesterly mid and upper level
flow. The surface CAA will build a surface ridge of high pressure
southward across the Plains. Expect cooler temperatures with highs in
the mid to upper 50s. Most of the area will see a freeze early
Thursday morning.
The sheared southern stream section of the original H5 trough will
retrograde southwest into northern Mexico and fill.
Thursday through Saturday:
Expect a warming trend as the surface ridge shifts east across the OH
River Valley. A northern stream H5 ridge will move east across the
Plains Thursday and Friday. An amplified upper trough will slowly
shift east into the western US. The upper ridge axis will move east
across the MS river Valley by Saturday. Highs will reach the 60s on
Thursday. Expect lower to mid 70s on Friday afternoon and mid 70s to
near 80 degrees by Saturday afternoon.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 626 PM CDT Sat Mar 30 2024
VFR conditions for the next several hours before low stratus
returns in advance of a surface warm front that is progged to
begin returning north. Should see mostly marginal VFR Cigs
through the period, but there could be a few hour window for IFR
conditions into the mid morning hours. Can`t rule out a shower
in the morning as well especially around the KTOP/KFOE terminals
but the chances remain too low to mention. Any Cigs should lift
into the afternoon and perhaps clear. Storms could form once
again Sunday evening but may hold until the after this period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Gargan
AVIATION...Drake