Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/01/24
Area Forecast Discussion
National Weather Service Cheyenne WY
834 PM MDT Sun Mar 31 2024
.KEY MESSAGES...
- Another round of snow is expected to develop this evening and
continue overnight. Winter Weather Advisories have been issued
for Converse, Niobrara, north Sioux, Dawes, and Box Butte
Counties. Here, 2 to 4 inches of snow is expected with locally
higher amounts along the Pine Ridge possible. Snow will taper
off Monday.
- Warmer and drier temperatures are expected Tuesday through the
end of the work week.
&&
.UPDATE...
Issued at 835 PM MDT Sun Mar 31 2024
It`s a dynamic evening across the area. An over performing
thunderstorm was able to tap into minimal instability but very
high shear and dropped up to nickel sized hail as it rode along
a boundary from Hawk Springs to Scottsbluff. This was fueled by
impressive dynamics in the marginal thermodynamic environment,
but since the storm already ran along this boundary and
stabilized the atmosphere there, expect no other area will have
enough to push a storm to produce hail. However, there is enough
to continue isolated embedded thunderstorms through the early
morning hours.
Additionally, the mid-level frontal boundary is pushing across
the area, currently crossing the I-25 corridor as it wraps into
the developing cyclone to our southeast. This produced a band of
mixed rain and snow and gusty winds along I-80, and is expected
to accelerate the temperature drop and transition to snow over
the next few hours. Updated the forecast to reflect this frontal
passage with a drop in temperatures and snow levels in its wake.
Still thinking most of the precipitation should end over the
High Plains outside of existing Advisory area before the air is
cold enough to support accumulating snow, but will continue to
monitor this evening.
.SHORT TERM /THROUGH TUESDAY/...
Issued at 250 PM MDT Sun Mar 31 2024
A bit of an uncertain forecast this evening and into Monday as a
semi-disorganized system brings another round of potentially
accumulating snow to the area. Based on the 18Z surface analysis, it
appears lee cyclogenesis has occurred based on the presence of
a surface low in east-central Colorado. The GFS aligns most
closely in location and timing of the surface low, therefore,
based much of the synoptic analysis on the GFS. While the
surface low is in Colorado, a 500 mb low will drift across
Wyoming tonight and into the day Monday. The ever so slightly
northwest to southeast propagation of the upper-level low will
push the surface low into east-central/southwest Kansas. GEFS
cluster analysis is pretty confident in the surface low
placement into Kansas through tonight. Surface low placement
becomes more uncertain headed into the day Monday. Regardless,
the cluster analysis either places the low in eastern Kansas or
the Oklahoma panhandle, both of which would not be conducive
locations for heavy precipitation across the CWA. On top of
this, this is a progressive system, so the window for
precipitation is relatively short-lived.
Currently, radar is lighting up with some light showers across the
area. A few observations sites are also reporting light rain and
even some thunder! Across much of the CWA, there are non-zero CAPE
values so a brief thunderstorm and/or a few rumbles of thunder
cannot be ruled out this afternoon and into the evening.
Showers and precipitation will become more numerous as the day
progresses due to the surface low strengthening. Hi-res guidance
shows widespread precipitation for areas east of the Laramie
Range this evening. One of the biggest challenges with this
forecast will be when rain transitions to snow as this will
largely determine total snowfall amounts. Substantial clearing
across much of the plains has allowed temperatures to warm into
the 50s. Areas further north have stayed in cloud cover with
temperatures in the 30s. These areas will likely see a rapid
transition to snow and higher totals. Areas further south may
not see a transition to snow until later tonight. Although there
is still uncertainty with precipitation types, there is high
confidence that the heaviest precipitation will occur this
evening and overnight.
With this forecast package, went ahead and issued Winter Weather
Advisories for Converse, Niobrara, North Sioux, Dawes, and Box Butte
Counties. Currently, confidence is fairly high in these locations
seeing the highest snowfall totals. Have the Wyoming counties
starting at 6 PM tonight as these colder locations will likely see a
quicker transition to snow. Snow in these locations will likely wrap
up by morning hours Monday, so have the Advisory in effect until 9
AM Monday. Snowfall amounts in these counties will likely be between
2 and 4 inches with locally higher amounts up to 6 inches possible.
With anticipating a later change over to snow for the Nebraska
counties, the Advisories start at 9 PM this evening and continue
through 3 PM Monday to account for any potential lingering snow
showers. Accumulations also will likely be in that 2 to 4 inch range
with locally higher amounts possible, especially along the Pine
Ridge.
Snow will taper off during the day Monday, leading to a chilly,
below average day. Luckily, by Tuesday, the upper-level trough
responsible for the snow will have pushed far enough to the east,
allowing for a ridge to build in its place. This will lead to a
sunny day with temperatures warming up to average for early
April.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 250 PM MDT Sun Mar 31 2024
All models in excellent agreement for mid to late week, showing
a high amplitude upper level ridge moving east into the Front
Range, and the high plains, on Wednesday and remaining over the
area through Friday. This ridge was result in a quick warming
trend over the area, with high temperatures likely returning to
the 60s and 70s across all of southeast Wyoming and western
Nebraska. Friday looks like the warmest day of the week as 700mb
temperatures climb to 6c to 8c during the day under south to
southwest flow aloft. Kept temperatures around 15 degrees above
normal during the day, but kept them slightly below consensus
guidance due to the possibility of mid to high cloud cover well
ahead of the next Pacific storm system. Kept POP near zero as
daytime convection appears unlikely due to the lack of moisture
and strong subsidence aloft.
The next Pacific storm system is forecast to push onshore
Thursday and early Friday, likely taking it`s time moving across
the Great Basin Region before it moves towards the Front Range
and adjacent high plains for next weekend. As with most systems
this spring/late winter, models are favoring the southern branch
of the jet stream with a potential surface storm developing
across eastern Colorado/western Nebraska/northwest Kansas as it
stalls across the high plains. Like the others before it, will
have to monitor this system closely over the next few days for
potential winter impacts...especially across southeast Wyoming
since it may be a tad too warm for accumulating snow across
western Nebraska. However, this may change. Trended POP/Weather
forecast towards CONSALL since the NBM is way too high early in
the period (Friday night/Sat) and too low late (Sat
Night/Sunday). With some disagreements on timing/onset and a
notable dry slot lifting north across the region on a few model
runs, decided to lower max temperatures slowly through the
weekend and keep them close to average, or slightly below
average, for now.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 529 PM MDT Sun Mar 31 2024
Forecast remains tricky this afternoon across southeast Wyoming
and Nebraska Panhandle. Continued to use LAMP and HRRR guidance
on timing of lifting and bringing back in IFR and LIFR
conditions. Short term guidance showing a band of rain and snow
dropping forming along the central Laramie Range and expanding
east through southeast into the Panhandle after 03Z or so.
Expect IFR/LIFR conditions with these bands as they move through
each airport.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 9 AM MDT Monday for WYZ101-102.
NE...Winter Weather Advisory until 3 PM MDT Monday for NEZ002-003-
095.
&&
$$
UPDATE...MN
SHORT TERM...SF
LONG TERM...TJT
AVIATION...GCC
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
627 PM CDT Sun Mar 31 2024
.KEY MESSAGES...
- A 30 to 50 percent chance of showers and storms continues
through Monday morning primarily for areas north of I-70. An
isolated severe storm producing marginally severe hail is the
main threat.
- More widespread thunderstorms are forecast Monday afternoon
through Monday night. Severe weather capable of producing all
hazards is possible, mainly near and south of I-70.
- Cooler and drier conditions return for the middle of the week,
with a widespread freeze possible (around a 50 percent chance)
Wednesday night.
&&
.DISCUSSION...
Issued at 214 PM CDT Sun Mar 31 2024
A lot of question marks remain with the forecast through
Tuesday, with convection-allowing models (CAMs) struggling with
the low-amplitude nature of weak vorticity maxima moving across
the central U.S. before the main show begins Monday afternoon.
For the most part, the forecast has transpired in the ballpark
of expectations today. A round of showers and storms has
affected southern Iowa and far northern Missouri most of the
day, and these should continue late this afternoon as they
progress eastward in tandem with a weak 700-mb perturbation as
evidenced via HRRR/RAP guidance. The main question is if
redevelopment of convection will occur farther south and west in
the destabilizing environment closer to the effective warm front
(roughly along the I-70 corridor early this afternoon). Past
HRRR runs as well as GFS-related guidance were fairly consistent
in developing isolated to scattered storms in a northeast-
southwest corridor just east of I-35 early this evening, but the
HRRR is waffling on this scenario today. Other convection-
allowing model guidance is considerably less aggressive,
developing most convection in north-central/northeast Missouri
well to the north of front. In fact, CAMs look awfully quiet
overnight in much of our CWA.
There is reason to believe these recent trends. Given the
presence of a weak midlevel vort max on the western/southwestern
periphery of the ongoing elevated convection near the IA/MO
border, there would likely be compensating subsidence on the
upstream side. Combined with larger-scale ridging enveloping
much of the central U.S., convective initiation may be generally
difficult to achieve. Though initiation may happen locally
(i.e., on an isolated basis), model soundings certainly lean
toward capping holding serve through this evening for most of
the area. Certainly cannot rule out some convection through this
evening, but did lower PoPs significantly in much of the region
through the early overnight hours.
If convection remains relatively sparse at best, this would
suggest that Monday may have more potential for severe weather,
as (1) the warm (quasi-stationary) front would remain in its
general position or even shift slightly northward and (2)
ambient instability would be present as deep convection develops
diurnally on Monday. However, various CAMs indicate that
additional subtle perturbations will eject from the main trough
well to the west through Monday afternoon. The 18z HRRR and 12z
NAM Nest both pick up on this, with bouts of convection in
portions of Missouri tomorrow morning into early afternoon. At
first glance, this seems overdone, particularly south of the
front, with considerable inhibition to overcome. What seems more
plausible is continued rounds of showers/storms well north of
the surface front. With this in mind, kept highest PoPs near the
Iowa border overnight into Monday morning and only gradually
increased PoPs elsewhere through early Monday afternoon, in
deference to the CAMs (but lacking the aggressiveness of, say,
recent HRRR/NAM Nest solutions).
My suspicion is that solutions closer to the WRF-ARW and FV3 may
be more realistic, with a general lack of convection through the
overnight followed by scattered storms developing Monday morning
with a perturbation ejecting through the lower Missouri Valley
at this time (but perhaps mostly to our east). Subsequently,
scattered to numerous (but initially discrete) storms would
develop during the afternoon and evening in the relatively
unperturbed warm sector of eastern KS and western MO as a much
stronger vort max affects the region. This would keep the
predecessor quasi-stationary front near the I-70 corridor (or
perhaps just a tad to the north), with an environment favorable
for supercell storms capable of large hail, damaging winds, and
isolated tornadoes (e.g., 0-6 kt bulk shear > 60 kt; MLCAPE >
1000 J/kg). The tornado threat is not particularly clear,
however, given fairly unidirectional flow and attendant modest
low-level shear/helicity in the pre-convective environment. As
alluded to above, the highest severe threat remains near/south
of I-70 on Monday, with timing generally between 3 pm and
midnight.
Meanwhile, additional rounds of elevated/non-severe convection
are depicted in much of the guidance Monday night and Tuesday
morning as the surface cyclone progresses through the MO/MS
Valleys. This may provide the bulk of the rainfall across the
region, with QPF generally between 0.5 and 1.5 inches. Notably,
however, far northwest Missouri may see considerably less total
rainfall because of the general southward trend in the
cyclone`s track seen the past 48 hours. Uncertainty remains
here, however, given much of the above discussion on the
position of the east-west oriented baroclinic zone through
tomorrow afternoon (and its resultant influence on the low`s
track).
The system should depart the region by Tuesday evening, with
cold advection providing a sharply cooler midweek period.
Temperatures still look to fall near or below freezing on
Wednesday night, so another round of frost/freeze products may
be required at that time. Otherwise, the highly amplified nature
of the departing system will allow for pronounced ridging to
move into the central U.S. to close the week. So another quick
warm-up is expected through next weekend. The next system looks
to affect the region just beyond the forecast period.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 627 PM CDT Sun Mar 31 2024
Lo conf fcst with the sfc front in the VC of the TAF sites
however, it does appear that the front will drop back thru the
TAF sites with MVFR cigs building in behind btn 03Z-05Z. Cigs
are expected to further drop into IFR btn 08Z-11Z before lifting
back to MVFR btn 15Z-17Z. VFR conds are expected by 19Z with
cigs lifting to around 4kft. A chc of tsra are poss at the TAF
sites aft 19Z however, much will depend on where the front is at
that time. Winds will be out of the NNE to begin the TAF pd
before veering to the NE by 03Z. Winds will then veer to the
east around 09Z before becmg southerly aft 16Z while remaining
blw 12kts.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.
&&
$$
DISCUSSION...CMS
AVIATION...73
Area Forecast Discussion
National Weather Service Green Bay WI
656 PM CDT Sun Mar 31 2024
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- Light precip is possible at times tonight into Monday. Light
snow may mix in with the light precip after midnight, but
chances are less than 10% for any accumulations. Spotty
freezing drizzle may also occur but confidence is extremely
low.
- Rain will change to snow Tuesday evening as cold air wraps
around a low pressure system to our east. Accumulation is
possible, especially near Lake Michigan. If this low tracks
further west, significant accumulations may need to be added to
the forecast for these areas.
- Winds will be on the increase Tuesday night, with strong gusts
in the area Wednesday. Widespread strong wind gusts up to 30 to
35 mph will be possible over land, with gusts up to 45 mph over
the open waters. Winds will cause travel impacts with any
snowfall Tuesday night and Wednesday due to low visibility.
&&
.DISCUSSION...
Issued at 316 PM CDT Sun Mar 31 2024
Short Term...Tonight and Monday
The latest RAP analysis and satellite/radar imagery show a cold
front sliding into north-central Wisconsin early this afternoon.
The boundary layer remains relatively moist ahead of the front with
dewpoints in the upper 20s to middle 30s. With diurnal heating,
the moist boundary layer has contributed to a MVFR cumulus field
across northern WI. The front itself is mostly inactive, with only
a few spotty returns showing up around Ironwood and spotty
ceilings below 3000 ft.
Meanwhile, confluent low to mid level flow has contributed to a
fgen band and light rain stretching from southern Minnesota to far
southwest Wisconsin. Most CAMS weaken this band as it moves east,
while also keep it just south of the CWA border this afternoon.
Trajectories are a little too close, so will add a small chance of
light rain to the forecast over central to east-central WI later
this afternoon into early this evening. This confluent zone is
north of a warm front that is lifting north across the mid-
Mississippi Valley.
Forecast concerns mainly revolve around light precip chances along
the cold front tonight followed by the warm front on Monday.
Tonight...The cold front over north-central WI will continue to
sag south and lose definition as it moves into central WI after
midnight. Saturation depth will increase some along the boundary,
but in general, forecast soundings show that the saturation depth
is meager and cloud bases are mostly above 3000 ft (isolated
areas to 2000 ft). If low level temps were colder, over water
instability could augment the low level saturation when winds turn
to the northeast late this evening into overnight. But latest
model runs indicate delta T`s around 7-8C which is not sufficient
for lake effect processes to take place. Will therefore just leave
a small chance of light rain in the forecast.
Looking at the fgen area to the south, CAMS have trended south
with the precip potential and keep activity most south of the area
through 7 am Monday. Therefore trended considerably drier with the
forecast over central to east-central WI overnight.
Trended low temps slightly warmer tonight due to cloud cover,
particularly over northeast WI where winds turn onshore. Far
northern Wisconsin may still see temps approach the median value
as skies will likely partially clear late behind the front.
Monday...Confluent flow increases further across the region with
evidence of weak shortwave impulses moving across the northern
Mississippi Valley. This will lead to a chance of light rain
spreading from west to east across central to east-central WI from
late morning through the afternoon. On the northern periphery of
the system, precip amounts will likely remain light as there is
only a 10-30% chance of a tenth or more of qpf by 7 pm Mon.
Long Term...Monday Night Through Sunday
The focus of the extended period will be the approaching low
pressure system from the Central Plains, that could bring active
weather into the forecast area
Monday night through Wednesday...
FGEN forcing will largely depart south and east Monday evening,
which should limit any remaining rain in the region for much of
the overnight period across central to east-central Wisconsin.
This dry period will be fairly short-lived however, as a strong
low pressure system crosses through Illinois into the lower
peninsula of Michigan by Tuesday afternoon and precipitation
returns to the region. This initial precipitation should still be
fairly light and limited for the time being.
The main timeframe of concern with this system however, is
Tuesday night through Wednesday. A strong secondary shortwave
will dig into the Upper Plains and western Great Lakes, which may
phase with the current surface low and lead to some
intensification of this system. The first and higher confidence
concern with this system will be wind gusts. Soundings bring
between 40 to 50 knot winds to 850, with fairly favorable
conditions to mix to the surface by Wednesday afternoon. This
would make for widespread gusts around 30 to 40 mph gusts over
land and possibly higher over marine. The second concern would be
a potential increase in precipitation, as the system possibly
retrogrades and brings the higher qpf and dynamics back to the
region. In the worst case, this would support significant
snowfall along the Lake Michigan shoreline and downstream of the
Bay of Green Bay. Delta-T values aren`t that impressive by
themselves (6-10 C or so) but could certainly enhance any
precipitation given the dynamics in this system. This would be the
worst case and only the GFS has this solution for now, so the
current forecast calls for lesser amounts of snow for the time
being. It bears stressing however, that given the winds during
this time period, any snow will cause travel impacts due to low
visibility from blowing and drifting.
Rest of the extended... While precipitation from the above system
will likely depart overnight Wednesday, winds may not settle until
the latter half of Thursday. Behind the departing system however,
a large upper ridge will build over Central CONUS. This will be
the start of a drier period for the end of the work week through
the weekend.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 654 PM CDT Sun Mar 31 2024
Confluent flow will take place across Wisconsin through the TAF
period with a cold front dropping into northern Wisconsin from
the north and a warm front lifting into northern Illinois from
the south. Precipitation along both fronts will mostly miss the
terminals across north-central and northeast WI.
Ceilings along the cold front to the north remain VFR. As the
front moves into far northeast WI this evening and winds turn to
the northeast, forecast soundings indicate MVFR cigs develop with
a low chance that saturation becomes deep enough for drizzle.
Confidence is low enough to leave drizzle out of the forecast, but
the MVFR ceilings will remain in the forecast.
With the shifting winds to the northeast, gusts to 20 mph will be
possible over the Fox Valley and lakeshore late tonight into
Monday. Light precip may also return to central and east-central
WI on Monday afternoon.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/Uhlmann
AVIATION.......JLA
Area Forecast Discussion
National Weather Service Omaha/Valley NE
614 PM CDT Sun Mar 31 2024
.KEY MESSAGES...
- 40 to 80% chances for showers and isolated thunderstorms
tonight through early Tuesday.
- There is a marginal risk for severe hail overnight tonight
from the Storm Prediction Center.
- Dry, warmer weather returns for the rest of the week.
&&
.DISCUSSION...
Issued at 131 PM CDT Sun Mar 31 2024
This afternoon - Tonight:
Mostly cloudy skies expected to hold through the rest of the day
today. A few isolated showers are occurring along and east of
the Missouri River in southeast Nebraska and southwest Iowa.
We`re even seeing a thunderstorm in our far southeast corner of
Page county, but as with the other storms, it should move off
to the east soon. The elevated instability is mostly east of our
area, so risk for any additional thunderstorms is low to nil
through this afternoon.
The surface low right now is to our south near central Kansas.
We are seeing isentropic upglide over the warm front to our
south which is causing the low clouds to spread north and the
isolated showers. These will continue through this afternoon
into this evening as the surface low and associated frontal
boundary stalls just to our south.
Monday - Tuesday:
Models have trended farther south with the track of the surface
low once it ejects east, which has lowered QPF amounts across
our area. We do see some elevated instability materialize Monday
morning. The Storm Prediction Center has us under a marginal
risk for severe hail for far southeast Nebraska and southwest
Iowa. There`s a large spread in the amount of model instability,
with a range from almost none to 2000 J/kg. If the NAM
materializes, we would see scattered storm coverage with quarter
to golf-ball size hail possible. If the more realistic RAP
materializes with around 1400 J/kg of CAPE, a couple isolated
storms develop with pea to nickel-size hail possible.
Rainfall amounts from this entire event will generally be up to
two tenths of an inch, with up to 0.35 possible for far
southeast Nebraska/southwest Iowa and near the northeast
Nebraska/South Dakota border. Precipitation will be exiting the
area during the day on Tuesday with a brief period of a rain-
snow mix possible on the very tail end of the precipitation.
A strong ridge builds in on the back side of this system Tuesday
afternoon. Clearing skies will allow temperatures to rise into
the 50s Tuesday afternoon, but northerly winds gusting to 30 to
35 mph will make it feel pretty chilly.
Wednesday - Saturday:
Strong northerly winds continue into Wednesday helping to keep
temperatures cool, with highs only in the low 50s. We see winds
relax on Thursday and start to shift to southerly Thursday night
into Friday which will spark the warming trend going into the
weekend. Friday and Saturday are looking very nice, with dry
weather and temperatures getting up into the upper 60s to low
70s.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 607 PM CDT Sun Mar 31 2024
MVFR ceilings are working their way into eastern Nebraska and
are expected to reach KLNK and KOMA by 00Z and KOFK by 02-03Z.
Northeasterly winds will remain above 12 kts through the
majority of the forecast period. Rain showers will work their
way into the terminals around 06-08Z with a few rumbles of
thunder possible. Rain will lighten into drizzle around 12-15Z.
Ceilings will gradually lower tonight, with IFR ceilings
expected overnight and a period of LIFR ceilings possible Monday
morning as drizzle and light rain continues to reduce
visibilities. Visibilities will improve late Monday afternoon
while IFR ceilings continue through the end of the forecast
period.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...McCoy
AVIATION...Wood
Area Forecast Discussion
National Weather Service Nashville TN
853 PM CDT Sun Mar 31 2024
...New UPDATE...
.UPDATE...
Issued at 847 PM CDT Sun Mar 31 2024
Another quiet night is ahead with abundant cloud cover and
southerly surface winds allowing for overnight temperatures to
only fall into the upper-50`s to mid-60`s. Overall, the forecast
remains on track with no major changes made. A disturbance passing
to our north Monday may allow for a few showers near the TN/KY
border, but most will remain dry with just cloudy skies until rain
and thunderstorm chances increase early Tuesday.
&&
.SHORT TERM...
(Rest of today through Monday)
Issued at 1106 AM CDT Sun Mar 31 2024
It is mild this morning but there is quite a bit of high clouds
and some Cu across the area. Despite the cloud cover temperatures
should be able to climb into the mid to upper 70s with even a
couple locations touching 80 degrees this afternoon. Moisture is
increasing with southerly low level flow. Dew points will climb
tonight into the upper 50s to lower 60s and the southerly surface
winds will persist. This will keep lows tonight in the lower to
mid 60s. A couple of showers are possible Monday morning along the
TN/KY border as a little disturbance passes by to the north.
Otherwise, Monday will be another warm and breezy day with mostly
cloudy skies.
&&
.LONG TERM...
(Monday Night through next Sunday)
Issued at 1106 AM CDT Sun Mar 31 2024
The main concern in the extended forecast continues to be on
Tuesday with the expectation of some severe storms. A wave of
energy within a larger positively-tilted, broad trough will eject
out of the SW CONUS on Monday with a surface low developing in
response. The surface low will move from the Ozarks into the
Midwest and deepen as Tuesday progresses. Storms could be ongoing
early Tuesday morning to our north and west. A couple of the CAMS
including the HRRR have some activity leaking into our northwest
around dawn. There could be enough instability in place where a
severe storm cannot be ruled out. The main show continues to
appear to be in the afternoon ahead of the cold front. Models
continue to show surface CAPE values between 500 to close to 900
J/kg during the afternoon. Models are suggesting storms will
develop ahead of the front over the western third of the CWA and
move eastward as the afternoon and evening progresses. 0-500mb
bulk shear will be ample to support organized updrafts with values
greater than 60 kts. 0-1 km SRH values could be between 200-250
m2/s2 over the eastern half of the area Tuesday afternoon. Storm
modes may be a mix bag of clusters, supercells, or line segments.
Given all of that damaging winds, large hail, and tornadoes all
look possible. The severe storm window should end between 00z and
03z Wednesday.
Behind the front, cooler air will filter in Tuesday night. An
upper low will dig southward Wednesday morning bringing a lobe of
energy through our area during the day. This will lead to cool
Wednesday with some scattered showers. The showers could linger
into Wednesday night. Thursday will be another cool day with highs
in the lower to mid 50s west of the plateau and 40s for the
plateau along with a stiff northwesterly breeze. Widespread frost
looks possible Thursday night and Friday night depending on how
strong the surface winds are. The upper low will slowly drift
eastward Thursday and Friday with upper ridging replacing the
broad troughing by Saturday leading to a rebound of temperatures
by Saturday.
&&
.AVIATION...
(00Z TAFS)
Issued at 659 PM CDT Sun Mar 31 2024
Weak upper level disturbance passage may bring light shwrs around
01/07Z CKV thru 01/15Z SRB/CSV, with another upper level disturbance
moving across northern portions of mid state 01/17Z-01/24Z bringing
light shwr potential CKV. Per expected isolated shwrs, not enough
confidence presently to mention developing at/moving across terminals,
but can not rule out development in vcnty. Low level atm pressure
gradient influences should continue to support gusts up to 25kts
thru 01/24Z. Sustained SW sfc winds around 10kts thru 01/24Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 66 82 67 77 / 10 10 50 100
Clarksville 66 80 66 76 / 10 20 60 90
Crossville 61 76 64 72 / 10 10 30 100
Columbia 65 81 66 76 / 0 10 40 100
Cookeville 63 77 64 72 / 10 10 40 100
Jamestown 60 77 62 72 / 10 20 40 100
Lawrenceburg 64 79 66 75 / 0 10 30 90
Murfreesboro 65 81 67 76 / 10 10 40 100
Waverly 66 80 64 75 / 10 10 60 90
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Clements
SHORT TERM...Reagan
LONG TERM....Reagan
AVIATION.....JB Wright
Area Forecast Discussion
National Weather Service New York NY
1031 PM EDT Sun Mar 31 2024
.SYNOPSIS...
Low pressure approaches from the west tonight, passing to the
south on Monday. A series of lows will develop along a stalled
front south of the area Monday night into midweek. The strongest
of the lows develops along it toward midweek, traversing south
of Long Island Wednesday night and eventually off the New
England coast Thursday night. High pressure stays west of the
area with low continuing to track slowly east Friday through the
weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
00z HRRR and 00Z NAM continue the trend of keeping the bulk of
the rain to our south and west through 6 am Monday. Adjusted
PoPs down a bit through this timeframe. Otherwise, the forecast
remains on track tonight.
A weak 1016 mb high slides offshore tonight. Low pressure approaches
from the west with some warm advection taking place early in the
morning. Clouds will increase through the night with temperatures
falling into the 40s. Light rain is possible for western areas
around day break.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
April begins on an active note, with a stalled boundary draped
over the Mid-Atlantic and multiple associated waves of low
pressure tracking near the region over the next several days.
A band of warm air advection and frontogenetic forcing approaches
the area in the morning hours. However, the latest 00z HRRR, NAM,
and hires FV3 have continued the trend with suppressing the
axis of the forcing, rain and low further south on Monday. Have
made some minor adjustments to the previous forecast to follow
the trend in the last several model cycles and the new 00z HRRR,
NAM, and hires FV3.
QPF has been lowered to reflect this shift, as were PoPs. It is
entirely possible inland areas only see trace amounts of rain
and the NYC metro could have around a tenth of an inch or less.
Regardless of where the axis ultimately sets up, this system is
a quick mover, with any rain ending by late afternoon. Those
looking for a reprieve from the wet weather however will be
disappointed as the next wave begins to enter the picture late
Monday night. Increasing PoPs toward daybreak Tuesday, when rain
redevelops from the west.
The rain, clouds, and light onshore flow Monday will allow for a
bit cooler conditions than recent days. Afternoon highs should
get into the lower 50s for most, or just a few degrees below
normal for early April. The exception looks to be interior CT,
which may be able to achieve mid 50s.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A broad area of low pressure will be stretched from the Ohio Valley
to the Mid-Atlantic on Tuesday. Moisture deepens as the day
progresses, with rain continuing to spread eastward across the
forecast area. An easterly low level jet may enhance the rain
potential over coastal and eastern areas, but generally looking at
light to moderate rainfall during the day. The system doesn`t make
too much eastward progression Tuesday night as a closed 500mb low
attempts to draw the parent surface low towards it in the vicinity
of the Great Lakes. The 500mb low will however help strengthen a
secondary surface low to our south. This low is then expected to
pass through or just SE of us Wednesday afternoon into night. This
maintains categorical PoPs Tuesday night through the daytime
Wednesday. Will leave in a slight chance of thunder for Wednesday
afternoon with models showing a little elevated CAPE and forcing
from the approaching low center. Rain during Wednesday will probably
be more on the moderate side for coastal/eastern areas with a llj
remaining in the vicinity.
Precip remains likely Wednesday night as the deepening surface low
will be slow to pull away due to the influence of the lagging 500mb
low to the west. Colder air wraps in from the north with snow in the
mix for inland areas. The low pressure system is then progged to
become stacked somewhere along the New England Coast by Thursday
evening. Precip chances remain over here through Thursday with the
cyclonic flow aloft and wrap-around moisture. PoPs highest over the
northernmost zones, and still cold enough for a rain/snow mix across
the interior in the morning. Looks like a breezy day as well with a
tight pressure gradient over the area. The storm continues to slowly
move and is expected to be off the coast of Nova Scotia on Friday.
Continued cyclonic flow aloft, and with a weak cold front/trough
with just enough moisture may trigger rain showers in the
afternoon. Maybe mixed with snow in the higher elevation N and W of
the city.
Will go with a dry forecast for the weekend as high pressure slowly
builds in from the west as this storm finally shifts far enough out
to sea.
High temperatures below normal Tuesday through Friday, a little
milder on Saturday, then back to near normal for Sunday.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Weak low pressure passes to the south on Monday.
VFR through much of tonight. Confidence continues decreasing
with regards to the extent of the rain and whether there will be
MVFR ceilings Monday morning into early Monday afternoon. It is
possible that flight categories will remain VFR with just some
light rain mainly the NYC metro, western Long Island and
potentially at KHPN. VFR appears likely in the middle to late
afternoon and evening.
WSW-WNW flow will weaken this evening with most locations
becoming light and/or variable by 03z. Winds at coastal
terminals should become NE-ENE early Monday morning and then
may briefly become E-ESE before shifting back towards the NE in
the afternoon. Wind speeds will be light and generally around
5-7 kt on Monday, so there is a chance at more variability in
wind direction.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low confidence forecast regarding the extent of -RA and any
MVFR ceilings Monday morning and early afternoon. There is also
a chance if MVFR ceilings develop that they linger into early
Monday evening.
OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
Monday Night: Mainly VFR early, then MVFR and rain developing
late.
Tuesday: IFR in rain. E-ENE G20-25 kt.
Wednesday: IFR in rain. E-ENE G20-30 kt. The rain could be mixed
with wet snow inland at night.
Thursday: MVFR or lower with lingering rain, possibly mixed
with wet snow inland. NW gusts 25-35 kt.
Friday: Mainly VFR. Slight chance of showers inland. NW
G20-25kt.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Winds and waves are expected to remain below SCA criteria through
Monday night.
SCA conditions become more likely Tuesday and especially going
through the midweek period. There will be potential for gales
Tuesday night through Thursday night.
Winds and seas increase Tuesday leading to small craft conditions
developing from south to north across the waters. Gales may even be
possible on the ocean Tuesday night, with a better chance of this on
Wednesday as low pressure approaches the waters. Can`t rule out the
the threat of gales on some of the other waters as well on
Wednesday. Gusty offshore winds are expected on Thursday and
Thursday night with SCA conds anticipated during this period. For
Friday, winds drop off a little with SCA conditions probably limited
to the ocean waters, but still possible over the eastern Sound and
bays.
&&
.HYDROLOGY...
Rain amounts from late Monday night through Thursday may be in the
range of 1.50 to 2.50 inches. Poor drainage and low lying areas
could very well experience some minor flooding, but anything more
impactful would be a low chance, mainly because of the long duration
of time the rain amounts would occur. This also takes into
consideration current flash flood guidance. Periods of heavier
rainfall are more likely to occur Tuesday afternoon through
Wednesday afternoon.
&&
.TIDES/COASTAL FLOODING...
Astronomically, by the middle of this week, we will be past the
halfway point between the full and the new moon cycles. There
will thus be an increase in the tidal levels around high tide.
This combined with a long period and increasing easterly flow
early to mid week will lead to more fetch and piling of water.
For some shorelines, particularly across the lower NY Harbor,
South Shore Bays, and Western Long Island for late Tuesday
night into Wednesday around the times of high tide, minor
coastal flooding will be possible.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DR
NEAR TERM...DR/DS
SHORT TERM...DR/DS
LONG TERM...JC
AVIATION...DS
MARINE...JC/DR
HYDROLOGY...JC/DR
TIDES/COASTAL FLOODING...
Area Forecast Discussion...UPDATED
National Weather Service Paducah KY
545 PM CDT Sun Mar 31 2024
.KEY MESSAGES...
- Monday will be another unseasonably warm day with temperatures
in the upper 70s to near 80 degrees.
- Thunderstorm chances remain low through at least the first
half of Monday, followed by the main risk arriving late Monday
into Monday evening. There is an enhanced risk for severe
storms, especially across southeast Missouri and southern
Illinois. Damaging winds is the greatest hazard of concern,
but tornadoes and large hail also remain possible. The severe
risk looks to peak between 12-4 AM.
- Tuesday and Wednesday will be very windy behind a cold front
with wind gusts over 30 mph, possibly nearing advisory
criteria.
- Temperatures will be 10 degrees below normal by the middle of
the week in the 50s/30s. Frost and possibly freeze headlines
still are looking likely, especially for Thursday night.
&&
.DISCUSSION...
Issued at 332 PM CDT Sun Mar 31 2024
Another unseasonably warm afternoon to end the holiday weekend as
visible satellite imagery shows scattered cu across much of the FA.
There is a 20-30% probability an isolated shower or storm tries to
develop along the I-64 corridor as a warm front continues to lift
north. However, the rest of today and tonight now looks to be mainly
dry as most of the overnight convection is progged to remain north
in the vicinity of I-70 with a robust warm sector dominating the FA.
Monday will start off mainly dry with just a few spotty elevated WAA
showers at most as a cap will be in place due to a stout EML around
800 mb. The only caveat is Monday afternoon along the I-64 corridor
as the 12z CAMs show a warm front near I-70 trying to sag south.
Both the HRRR/ARW show discrete storms just north of the CWA border
with concerning long 0-3km helicity tracks. Any slight shift south
in the boundary would mean the potential for a few severe storms as
it is likely there would be enough forcing to overcome the cap.
Models show a narrow-axis of about 1000-1500 J/kg of MLCAPE with
rich moist theta-e values 340K. Combined with 50-60 kts of effective
bulk shear, all severe hazards would be possible with a discrete
supercell. It will likely not be until the morning when we will have
a better handle on this initial conditional risk as residual outflow
boundaries from the overnight convection will have a big influence.
By Monday evening, the main severe weather risk will begin to arrive
from the west as the nose of a 70-90 kt mid-level jet causes rapid
synoptic-scale forcing for ascent. The general trend among the CAMs
is for convection across southwest Missouri to grow upscale into a
QLCS for the FA by 05-09z as a 500 mb shortwave and sfc low pressure
lift northeast across Missouri. Despite the loss of diurnal heating,
the parameters will still be quite favorable with 750-1000 J/kg of 0-
1km MLCAPE and 0-3km shear increasing rapidly to 40-50 kts as a
nocturnal LLJ at 850 mb ramps up. Rapid height falls and cooling
aloft result in steeper 700-500 mb lapse rates of 7.0-8.0 C/km to
support thunderstorm updrafts. Despite the favorable thermodynamics,
the biggest forecast question for the PAH CWA is how cool pool
dominate does the convection over SW Missouri become by the time it
reaches our region Monday night into early Tuesday morning.
The 12z HRRR is the most robust in showing multicellular
storms over southeast Missouri growing upscale into a bowing
segment ahead of a cold front that plows through most of the FA.
Other CAMs such as the ARW/NAM are a few hours slower with
convective initiation which limits upscale growth to the northwest
counties in southeast Missouri and southern Illinois. Given the lack
of consensus, it is really hard to narrow down the meso details, and
is why SPC now only has a broad 5% TOR in their D2 enhanced risk.
Overall, we are the most confident in there being a damaging wind
threat with a line of storms, but a few tornadoes are also possible
given 0-1 km SRH values of 100-200 m2/s2. WPC also has a slight risk
for excessive rainfall, but we think the risk for flash flooding is
very marginal as most areas can handle the 1-2 inches of QPF that is
progged across portions of the FA.
With that said, fropa does not occur with the cold front until
Tuesday as some redevelopment of convection is possible along the
boundary across the Kentucky Pennyrile and southwest Indiana where
SPC has a slight risk in their D3 outlook. If enough heating occurs,
damaging winds and large hail would be the main hazards of concern
given sfc-6km bulk shear of 60-70 kts, 750-1000 J/kg of MLCAPE, and
0-3km theta-e difference of 20K. A tight pressure gradient behind
the front allows for dry air to quickly advect during Tuesday
afternoon and evening as a potent 500 mb trough digs into the Ohio
Valley. Wind gusts between 25-35 mph will be possible with northwest
flow as a result. Would not be surprised to see these winds trend
closer to wind advisory criteria given very robust mixing that
extends up to 800 mb. In fact, Wednesday will feature an even better
chance at exceeding 40 mph gusts with the momentum transfer
extending above 750 mb. This is due to sfc low pressure deepening
over the great lakes with the GFS showing sfc pressure down to 979
mb! Some wrap around moisture will also set the stage for scattered
convective showers. If this pattern is not wild enough for early
April, would not be surprised if a few locations see some graupel
showers or even a few snowflakes. Thermal profiles are very cold
aloft with saturation around -10 to -12 C and a very low WBZ below
900 mb.
The highly amplified synoptic pattern will not only mean strong
winds but also potential frost/freeze headlines as temps in the
50s/30s are progged for Wednesday and Thursday. It is looking likely
winds will be strong enough Wednesday night to mitigate frost
concerns, but Thursday night still looks to feature the best
synoptic setup with radiational cooling as sfc high pressure begins
to settle over the FA. We will still need to watch for the typical
cold climo spots, especially near Mount Vernon to fall below
freezing. Temps do eventually moderate by next weekend as the ridge
axis associated with a omega pattern eventually moves over the FA
allowing for southerly return flow. NBM also keeps the PoPs silent
through much of the weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 545 PM CDT Sun Mar 31 2024
Ceilings may deteriorate to MVFR tonight as moisture surges in
from the south and an inversion establishes in the 2500-3500 ft
level. A moderate southwest wind is expected to persist most of
the night picking back up after daybreak with VFR conditions
emerging as the overcast deck rises above 3kft. There is a small
chance for thunder over SWIN and NW Kentucky in the late
overnight depending on how activity over central Illinois gets
going this evening. The broader convective chances should hold
of until after the new TAF period.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
DISCUSSION...DW
AVIATION...JGG
Area Forecast Discussion
National Weather Service Pittsburgh PA
731 PM EDT Sun Mar 31 2024
.SYNOPSIS...
Multiple rounds of showers and thunderstorms, possible strong to
severe at times, are expected through Tuesday. The greatest
potential for flooding and severe thunderstorms will be Monday
night and Tuesday.
&&
.NEAR TERM /THROUGH MONDAY/...
KEY MESSAGES:
- Mainly dry evening
- Showers and thunderstorms return after midnight
---------------------------------------------------------------
Only minor changes for the evening update. PoPs were refreshed
with the latest blended and hires data. Overnight lows were also
updated with the same data.
Previous discussion...
The next batch of activity is developing over southern Iowa and
northern Missouri in area of 700 mb warm advection with the
next low pressure wave. The NAM develops an area of intense 700
mb frontogenesis over northern IL and northern IN this evening,
and then translates it east into northern Ohio and western PA in
the 06 to 10z time frame.
However, there is some spread in CAM guidance in where this zone
of strong ascent and elevated thunderstorms set up, with the
HRRR trending a lot farther south focused closer but still north
of the surface boundary along the Ohio River. This scenario
seems less likely, so expect the corridor of storms to be a bit
farther north like other guidance. Given several rounds of
thunderstorms are likely between tonight and Tuesday afternoon,
a Flood Watch has been issued for the southern tier of counties
starting a 2 am tonight.
These elevated storms will pose a hail risk overnight given the
strong deep layer shear and low wet bulb zero heights.
&&
.SHORT TERM /MONDAY NIGHT/...
KEY MESSAGES:
- More widespread showers/storms Monday night, with potential
for flooding due to heavy rain especially in areas south of
I-70.
-----------------------------------------------------------------
Showers and thunderstorms will be ongoing Monday morning as a
passing disturbance exits to the east. Instances of heavy rain are
possible in this morning round, with localized flooding in low-lying
and flood-prone areas possible, especially where any heavier rain
fell during Saturday evening`s thunderstorms. A brief lull in rain
is expected during the day on Monday.
Yet another disturbances moves along the nearly-stationary front
Monday night, bringing another round of widespread rainfall with
even greater flooding rain potential. By this time, portions of the
local area may have already seen upwards of 1.0-1.5 inches of
rainfall between the Saturday and Sunday night waves. The newest run
of the NBM shows consistency with this. This will mean soils could
be saturated by the time the Monday night disturbance moves through,
leading to more runoff potential and a heightened risk for flash
and/or areal flooding due to heavy rain.
With the previous 2 disturbances passing through in this pattern, it
stands to reason that the boundary being wash out a couple times
from Sunday and Monday, the potential severe convection on Monday
night has slid a bit further south and is now focused along the
southern fringe of the CWA, along and south of a line from
Zanesville, OH to Morgantown, WV. Instability is marginal at best,
with HREF mean MUCAPE of only 100-250 J/kg in that area during from
00-06Z Monday. Still, there could be just enough support there for a
low-end damaging wind and hail threat. Most of the efficient
rainfall and stronger convection should wane or drop off to the
southeast by 12Z Tuesday morning.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
KEY MESSAGES:
- Showers, heavy rain, and a severe storm potential Tuesday.
- Colder and windy for the second half of the week with rain
and snow showers.
-------------------------------------------------------------------
Model ensembles indicate warm front should continue lifting
north across the region Tuesday, as a surface low tracks toward
the Lower Great Lakes and Upper Ohio Valley region. Ongoing
locally heavy rain is possible, continuing the flood potential.
Surface heating south of the front should result in increasing
instability through the day Tuesday. Strong shear is also
progged through peak heating, as the surface low`s associated
cold front approaches. It is looking increasingly likely that
severe storms will be possible in the afternoon and evening
across at least the southern half of the region, with greater
focus along and south of I-70. There is some guidance that
suggests a more southerly track with the setup of the boundary.
However, there is plenty of forcing along the cold front
Tuesday night with more solutions indicating the main threat
will come in the form of a squall line along that front.
The front should cross the area by late Tuesday night, as the
parent shortwave trough closes into an upper low across the
Lower Great Lakes and Upper Ohio Valley region. Rain and snow
showers are expected through at least Thursday as model
ensembles indicate the low will persist across the region. The
upper low should exit the region Friday, with dry weather
returning as high pressure settles in for Saturday.
&&
.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
All ports have improved to VFR in a brief reprieve before the
next disturbance riding a stationary front. As it does so,
rain and a few storms will overspread the region from west to
east and cigs will drop. Chances of thunder are greater than
30% to 40% south of I-70, justifying a TEMPO mention for the
period of peak probability. VCTS was denoted when probabilities
decreased as the wave moves east. There is high consistency in
guidance at keeping convective elements nearer the southern tier
of ports, though VCTS was denoted for the Pittsburgh metro
terminals when chances are highest, yet less than 30%.
Within rain and storms chances of dropping to MVFR vis are
roughly 40% to 70% across the entire region with a local maxima
in the the Pittsburgh metro with lower convective activity, yet
higher rainfall rates. On the other hand, MVFR cigs are 70% to
100% likely. IFR cigs are roughly 50% to 80% likely through the
predawn and morning hours. Some minor improvement is possible in
diurnal trends before the next wave moves in Monday night.
.Outlook...
Additional restrictions in showers and a few thunderstorms are
expected Monday night through Tuesday night as a series of low
pressure systems move along a quasi stationary front. Gusty W-NW
wind, rain and snow showers, and restrictions are expected to
continue Wednesday and Thursday as the last low in the series
crosses the region, and pulls a cold front across the region.
&&
.HYDROLOGY...
Widespread rounds of rain will periodically continue through
Tuesday. The initial rounds should act to saturate the ground,
resulting in an increased flood potential as additional showers
and thunderstorms occur, especially later Monday and Tuesday.
Ensemble probabilities for at least 2 inches of total rainfall
range from 30-60 percent, with the highest values seen across WV
and the Laurel Highlands. In general, 1-3 inches of total
rainfall is expected through the period, with localized higher
amounts possible across WV. The highest rainfall rates are
expected to fall Monday night into Tuesday morning. This may
result in areas of flooding or flash flooding. Our area remains
in a Marginal Risk (1/5) for excessive rainfall during this
period.
Model ensembles also continue to indicate rises on area rivers
as runoff from the rainfall occurs.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch from 2 AM EDT Monday through Tuesday evening for
PAZ031-075-076.
OH...Flood Watch from 2 AM EDT Monday through Tuesday evening for
OHZ057>059-068-069.
WV...Flood Watch from 2 AM EDT Monday through Tuesday evening for
WVZ004-012-021-509>514.
&&
$$
SYNOPSIS...Cermak/Shallenberger
NEAR TERM...Craven
SHORT TERM...Cermak/Shallenberger
LONG TERM...Cermak/Shallenberger
AVIATION...Milcarek
HYDROLOGY...MLB
Area Forecast Discussion
National Weather Service Phoenix AZ
506 PM MST Sun Mar 31 2024
.UPDATE...Updated 00Z Aviation Discussion.
&&
.SYNOPSIS...
A slow moving storm system will pass through the Desert Southwest,
bringing periods of scattered showers and thunderstorms to the
region through Monday. Warmer and drier conditions look to return by
the middle of the week with temperatures rising back to near normal
levels. Another potential weather system will impact the region late
this week into next weekend, resulting in cooler temperatures and
bringing additional rain chances to southcentral AZ.
.DISCUSSION...
An active period of weather is underway across the Desert Southwest.
Latest area radars and visible satellite imagery show a large fetch
of precipitation and cloud cover stretching from the International
Border through southcentral AZ. This line of showers is associated
with an area of lift ahead of a deep upper low which is located
just off the coast of SoCal. The edge of the cloud/rain shield is
now through the western half of Maricopa County and will continue
to slowly edge ewd over the next several hrs. Rainfall totals so
far have ranged from around 0.05"-0.25" across the western half of
the region and up to 0.20"-0.50" across southcentral AZ including
the Phoenix Metro. Phoenix has already set a new daily rainfall
total for March 31st of 0.32" which breaks the previous record of
0.27" set in 1949.
Recent visible imagery shows abundant clearing present across
southeast CA and southwest AZ. This area is where we are expecting
another round of shower and thunderstorms to develop this afternoon.
Latest RAP mesoanalysis shows surface based CAPE now approaching
150- 250 J/kg across southeast CA and southwest AZ. Lapse rates
will also continue to increase to around 7-8 C/km as cold air
aloft moves in ahead of the approaching upper low. HREF paintball
plots are indicating widely scattered convection will initiate
around 21Z and persist through this evening. Main concerns with
this next round of showers and storms will be brief heavy
rainfall, wind gusts around 40 mph, and small hail. This activity
is expected to slowly progress ewd into the central deserts of AZ
by this evening and persist through the overnight period, bringing
additional rainfall amounts around 0.25"-0.50" to the lower
deserts and possible up to 1.00" in the higher terrain areas NE of
Phoenix. The threat of flash flooding remains low, although there
could still be some minor flooding, such as road ponding and
rises in area washes and creeks tonight.
On Monday, the aforementioned upper low will begin to weaken and
transition into an open trough. The trough axis will pass overhead
early Monday morning which will allow drier air to begin filtering
into the western half of the forecast area. Ongoing showers across
southcentral AZ will begin to taper off from W to E off throughout
the day with rain chances diminishing from 60-70% Monday morning to
around 20-30% across southcentral AZ by Monday afternoon. Since the
region will still be under the influence of decreased heights aloft,
well below normal temperatures will continue with highs only
expected to reach the mid 60s across the central deserts and lower
70s along and west of the Colorado River.
&&
.PREVIOUS DISCUSSION...
Upper level troughing will continue to weaken and exit east of
our region on Tuesday with ridging beginning to build back in over
the Desert Southwest. As this occurs, temperatures will rebound
quickly with afternoon high temperatures reaching back into the
mid-to-upper 70s on Tuesday and lower 80s on Wednesday across the
lower deserts. Temperatures will peak on Thursday in the mid to
upper 80s in most locations. However, these warmer temperatures
are not expected to last long. Ensemble guidance shows another
trough moving through the region for the end of the workweek and
heading into the weekend, which would result in another cooling
trend. There is still some disagreement with the ensemble models
with exactly how far south the trough digs as well as with the
exact timing of the trough. At this time rain potential is low
with NBM PoPs peaking around 20-25% across the high terrain of
southcentral AZ on Friday. Typical breeziness is also expected
with this system and looks to develop as early as Thursday.
&&
.AVIATION...Updated at 0005Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
An area of weakening convective showers will pass over mostly
KPHX, KSDL, and KDVT over the next hour, temporarily bringing BKN
CIGs around 3-4 kft. A light passing shower reaching the terminals
cannot be ruled out in the next hour. Going into the evening,
further convective shower may develop to the west and south,
moving over the metro sites before the main push of SHRA/TS
associated with the center of the low pressure. Showers and
thunderstorms that reach the terminals before the main push of
SHRA/TS are currently represented with VCSH starting between
02-03Z this evening. The best chance (30-40%) for MVFR or lower
CIGs is expected after 07-09Z, otherwise, CIGS will mostly be aoa
4 kft overnight. Visibilities could (20-30% chance) drop into the
MVFR range during heavier rain. RA/TS chances begin to lower
monday morning around 15-16Z into Monday afternoon, falling under
20%, but some spotty activity may still develop through the
evening. CIGs will prevail in the 050-070 range and at times dip
lower in RA/TS. Cloud coverage and bases improve heading into
Monday afternoon. E to SE winds will prevail through Monday
morning, but could temporarily veer S-SW at times this
evening/tonight with convective activity. A full W shift is
expected Monday afternoon. Wind speeds will mostly remain aob 10
kts sustained through Monday.
Southeast California/Southwest Arizona including KIPL and KBLH:
A round of SHRA with embedded TS through early this evening will
be the main aviation issue during this TAF cycle. VFR CIGs are
expected to prevail, with bases mainly around 050-060, however,
there is a low chance for MVFR CIGS with any heavier TSRA
activity. Most shower activity will come to an end this evening
before midnight. Winds will favor a southerly component through
most of the evening at KBLH, while current E winds at KIPL are
anticipated to shift to W-NW before going VRB later tonight. Winds
in the vicinity of RA/TS could become erratic and briefly very
gusty at KBLH, with a 30% chance for convective wind gusts over 30
kts.
&&
.FIRE WEATHER...
MinRH`s will be elevated over the next couple of days (30% or
higher) thanks to a cold front that is currently moving through
the region. Winds ahead and along the front may gust 20-30 mph,
however winds speeds are expected to be less than that behind the
front. This cold front will also bring widespread wetting rains,
especially to the eastern districts. Lingering shower and storm
chances will remain through Monday. MinRH`s will then once again
lower going into the middle of the week, generally 15-25% across
the lower deserts. Temperatures will be well below normal through
Monday, with a warming trend back towards normal and slightly
above normal into the middle of the week.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Salerno
PREVIOUS DISCUSSION...Berislavich
AVIATION...Whittock/Benedict
FIRE WEATHER...Berislavich
Area Forecast Discussion
National Weather Service Pueblo CO
916 PM MDT Sun Mar 31 2024
.KEY MESSAGES...
- Light to moderate snow will continue along the Continental
Divide overnight, especially over the eastern San Juan
Mountains
- Lull in precipitation Monday morning, then showers and thunderstorms
(with snow above 6500 feet) become widespread across all of
srn Colorado in the afternoon
- Snow comes to and end through Tuesday morning, with brisk
northerly winds remaining through the day.
- A warm-up begins Wednesday, with above normal temperatures
and critical fire weather conditions persisting into the
weekend across the plains.
&&
.UPDATE...
Issued at 915 PM MDT Sun Mar 31 2024
Updated to expire the Red Flag Warning at 9 PM. Humidity values
have started to recover, with most areas on the plains seeing
values near 20 percent. Winds will continue to be gusty, mainly
along the eastern mountain lee slopes into the southern I-25
corridor over the next couple of hours. Mozley
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 252 PM MDT Sun Mar 31 2024
Currently, windy day across all of srn CO, and a few lower elevation
locations (KALS and KTAD), have gusted to around 55 mph so far,
while gusts of 60-70 mph have been noted over the higher terrain.
Most models and statistical guidance suggest wind gusts are peaking
now (3pm), and will diminish for the rest of the afternoon into the
evening, though conditions will still be breezy until around sunset.
Along the Continental Divide, occasional snow showers have been
noted through the day, though accumulations have been limited to
mainly the higher peaks. Overnight, winds diminish, while mainly
light snow persists over the mountains, especially back toward the
Continental Divide. Will keep winter wx advisory going for the ern
San Juans through the night, where at least a few inches of
additional accumulation are forecast. Should stay breezy enough to
keep min temps on the mild side, with most of the plains/I-25
corridor staying above freezing.
On Monday, lull in precipitation looks likely in the morning, then
upward motion and instability increase in the afternoon as upper low
closes off over nern NM and surface low spins up in the TX
Panhandle. Expect showers and thunderstorms to become widespread
across the area, with heavy snow in the Sangres/Wets/ern San Juans,
especially above about 7k feet. Along I-25 and across the plains,
focus for precip shifts quickly southward toward the NM border by
late afternoon, as stronger frontogenesis sags southward through
CO. Still some question as to exactly where the heaviest band of
precip sets up, with most NAM/GFS/ECMWF solutions trending south
into nern NM/OK Panhandle, while last few runs of the HRRR are
slightly north, mainly along and just south of the Arkansas River.
Precip should stay mostly rain (maybe some graupel/wet snow above 6k
feet) at lower elevations, as NBM and other statistical guidance
keep surface temps well above freezing along and east of I-25.
Wherever the band sets-up, QPF looks fairly heavy, with current
forecast pointing toward perhaps 0.75 to 1 inch of liquid possible
along the CO/NM border east of Raton Pass. For highlights, converted
the winter storm watch to a warning for the srn Sangres, while added
an advisory for the nrn Sangres/Wets and kept the ern San Juan
advisory in place. Given rather high snow levels (6k-7kfeet) during
the day, suspect we`ll see a rather tight gradient in snowfall
amounts, which is typical of spring weather systems.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 252 PM MDT Sun Mar 31 2024
Monday Night and Tuesday..
High res model guidance moves the surface low towards the Oklahoma
panhandle by Monday evening. Both the HRRR and the NAMnest spread a
large area of northerly winds and precip chances behind the low
across our plains, mainly along and south of highway 50, from around
6pm to midnight. Most precipitation is expected to fall as rain and
rain/snow mix for lower elevations, though some brief changeover to
snow will be possible after sunset. The main focus area for snowfall
Monday night will remain over our southern Sangres and the Raton
Mesa, where a Winter Storm Warning will remain in effect until 3am.
Additional snow totals of around 6 to 8 inches will be possible from
6pm through 3am Monday night/Tuesday morning. This will make for
hazardous driving conditions through the overnight hours, especially
through La Veta Pass and the Southern I-25 corridor over the Raton.
Overnight low temperatures will be near freezing for the plains both
Monday night and Tuesday night. Rain and snow showers are expected
to come to an end from north to south through the morning hours,
with dry conditions moving in by around 10am at the latest. Our
temperatures warm into the 50s and 60s during the daytime hours for
the plains and mountain valleys , but with post-frontal northerly
winds gusting up to 30 mph throughout the day, many of our plains
locations will likely still feel pretty chilly for Tuesday.
Wednesday and Thursday..
By Wednesday, models bring the eastern periphery of the ridge
overhead. This will kick off a warming trend, and usher in a period
of at least a couple of days with generally dry and quiet weather
for Wednesday and Thursday. Daytime highs will be above normal both
days, and winds will be generally weak under the ridge. Relative
humidity values will be low, though given weak winds, not expecting
critical fire weather headlines at this point.
Friday Onwards..
By Friday, models bring another low onshore over California,
increasing southwesterly flow aloft over our region. With dry air
already expected to be in place over Colorado, critical fire weather
conditions will be likely (60-70%) if this forecast trend continues.
If the system speeds up at all, it is possible we could have gusty
enough winds to see critical fire weather conditions for portions of
the area on Thursday as well. Current solutions bring snow chances
back into the Continental Divide by Friday. Though timing and storm
track remain uncertain at this time, for now it seems like precip
chances will remain confined to the higher terrain, while the plains
will be more likely to see continued gusty winds and critical fire
weather for next weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 252 PM MDT Sun Mar 31 2024
At KALS, VFR the next 24 hrs, as any MVFR vis from blowing dust
should end by 00z. Gusty sw winds will gradually diminish after
02z, while VFR cigs slowly lower. VCSH possible after 06z, then
an increasing chance for -shra/brief -tsra after 18z as upper
level trough moves across srn CO.
At KCOS and KPUB, VFR until 18z-20z Mon, then increasing potential
for at least MVFR cigs/vis as -shra/brief -tsra develop with upper
trough moving through the region. Gusty sw winds will diminish this
02z-03z this evening, then turn nly Mon morning by 12z at both
sites. North winds will strengthen Mon afternoon, with gusts
20-25 kts after 18z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight MDT Monday night for
COZ068.
Winter Weather Advisory from 6 AM Monday to 3 AM MDT Tuesday
for COZ072-073-079-080.
Winter Storm Warning from 6 AM Monday to 3 AM MDT Tuesday for
COZ074-075.
&&
$$
UPDATE...MOZLEY
SHORT TERM...PETERSEN
LONG TERM...EHR
AVIATION...PETERSEN
Area Forecast Discussion
National Weather Service Reno NV
307 PM PDT Sun Mar 31 2024
.SYNOPSIS...
The final chances for showers with this current weather
system look to be this evening for mainly southern portions of
the region before precipitation chances end around midnight.
Drier conditions and increasing temperatures are expected to start
the work week following this weekend`s precipitation. By midweek,
another active weather system looks to impact the region bringing
increased precipitation chances and cooler temperatures.
&&
.DISCUSSION...
Rest of today through Wednesday morning:
According to the latest RAP analysis, the REV CWA currently has a
north-northeasterly flow aloft as the rear portion of positively
tilted upper air trough resides above with an upper air ridge moving
over the Pacific Coast to the west. Current radar imagery along with
surface observations report some isolated showers still lingering across
the region. Model guidance projects the CWA`s upper air flow
becoming more northeasterly through the rest of today and going
into Monday as the western ridge progresses eastward. Forecast
guidance continues the eastward progression of the ridge through
Monday and Tuesday with the axis of the ridge passing over the CWA
during the Tuesday afternoon hours. By Wednesday morning, models
predict an upper air trough moving into the Pacific Northwest
which causes the CWA to turn west-southwesterly as the axis of
the ridge progresses over the Rockies. At the surface, the latest
CAMs runs suggest chances for some scattered snow showers this
evening for the southern half of the Sierra Mountain portion of
the region with some possible isolated light showers in the
southern half of the northwestern NV portion. The mountain crests
may see up to around an additional 6-10 inches of snow within Mono
County going into the night with a few inches possible in lower
elevations. Snowfall amounts in areas where it snows in
northwestern NV look to see a possible trace to around less than
an inch. There is less than a 15% chance some showers may contain
some thunder too with models showing low CAPE values around
100-200 J/kg this afternoon and evening. Around midnight tonight,
precipitation chances expect to diminish. On Monday, a surface
high moves into NV underneath the ridge allowing for cloud cover
to be minimal, drier conditions, and a warming trend to begin that
continues through Tuesday and early Wednesday. There may be some
breezy to gusty winds in the Sierra crest later Monday with gusts
possibly up to around 50-60 mph.
Wednesday Afternoon through Friday:
On Wednesday afternoon, models have the front portion of the western
trough moving over the CWA allowing for a mostly southwesterly flow
through the remainder of the day. Model guidance then has an upper
air low develop within the trough by Thursday afternoon which gives
the flow over the CWA a more southerly direction. There is a slight
position difference in this low seen between some models as the GFS
has it over the northern CA coast while the ECMWF has it over the OR
coast. But on Friday, models get back into step as they project the
low to pass over the CWA by the afternoon hours. With this setup
above, forecast guidance depicts a surface low moving from OR into
northern NV by Wednesday evening allowing for cooler air to push
into the region as well as mountain snow and valley rain chances to
return to the region. As temperatures cool on Thursday, some snow
looks to mix into the valley rain overnight with the P-type
transitioning to all snow on Friday. When looking at 72 hour
snowfall total probabilities through Friday night, currently the
Sierra crest has a 40-60% chance of 6 inches of snow or greater,
around 10-20% chance of 8 inches of snow or greater, and less than
5% for 12 inches of snow or more. Lower elevations see a 20-50%
probability of less than one inch of new snowfall accumulation
across the region. The event is still quite the ways out, so exact
snowfall totals at this time remain uncertain. Please continue to
watch for future forecast updates. Another concern looks to be the
increased winds with the presence of this low in NV for a few days
causing a pretty tight pressure gradient as a result. The latest
model runs continue to show the potential for Sierra ridgetop gusts
around or over 70 mph along with the potential for gusts around 30
mph in the lower elevations on Wednesday and Thursday. Winds look to
slowdown a bit though remain breezy on Friday afternoon with an NBM
probability near 50% for around 50 mph wind gusts in the Sierra
crest. As for cooler temperatures, the forecast currently calls for
overnight lows down to the 20s with some portions seeing upper teens
possible. Later on Friday, models project the surface low moving
eastward causing precipitation chances to decline going into
Saturday.
Next Weekend:
Models start to become more chaotic going into Saturday though they
seem to agree generally with the upper air low moving out to the
Rockies by late Saturday morning and being trailed by a weak upper
air ridge feature that moves over the CWA during the evening. On
Saturday night and into Sunday morning, there looks to be another
possible low developing in the Pacific Northwest though models
show some good discrepancy in its intensity and progression. While
there may be a break in precipitation chances for a portion of the
region on Saturday, it looks to be short lived as the upper air
pattern suggests the possible of more precipitation chances on
Sunday. There is still a good amount of uncertainty this far out,
so this will be monitored going forward to see how models resolve
this situation in future runs.
-078
&&
.AVIATION...
VFR conditions look to return to the REV terminals this afternoon
though there may be some vicinity showers. Possible MVFR conditions
may occur should a shower move near a terminal particularly KMMH
this evening as snow shower chances increase in Mono County this
evening. With lighter winds expected for tomorrow, KMEV and KTRK may
see some MVFR visibilities with some fog developing after midnight
that looks to last until around 15Z. Mostly clear skies are expected
going through the rest of Monday with a surface high moving into the
region. FL100 winds look to pick up midday blowing out of the north-
northeast, so there may be some potential for LLWS.
-078
&&
.AVALANCHE...
A period or two of snow showers within the region remains for
this afternoon and evening particularly for Tahoe Basin as well as
Mono County before precipitation chances end going into tomorrow.
* Additional liquid totals (SWE) through tonight: 0.10-0.50
inches.
* Additional snowfall: 2-6 inches of new snowfall.
* Peak Snowfall Rates: the latest HREF run shows rates to be 1-1.5
inches per hour though there is the possibility of some brief
convective showers that might yield slightly higher rates.
* Snow-Liquid Ratios: Still look to be around 10-14:1.
* Winds: Increasing northeast winds with gusts up to around 50-60
mph over the ridgelines are in the forecast for later tonight
through Tuesday morning.
-078
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Charleston WV
1116 PM EDT Sun Mar 31 2024
.SYNOPSIS...
Shower and isolated thunderstorm chances overnight along a
lifting frontal boundary. Flooding and strong to severe storms
are possible Monday and Tuesday. Cooler Wednesday into Friday.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 1100 PM Sunday...
Updated PoPs to represent a line of showers and isolated
thunderstorms that has developed across the northern portion of
the CWA along a northward lifting warm front. Activity should
continue to progress steadily northward over the next few hours,
becoming confined to the far northern portion of the CWA, or
perhaps exiting completely. An isolated strong storm or two
remains possible, with the main threats being small hail, gusty
winds, and locally heavy rain. Otherwise, the other update was
to add a bit of patchy fog across the southern/eastern river
valleys, especially in areas that received rainfall today.
Sfc-H850 flow steadily increases overnight, so fog coverage
should level off, or even scatter out as the night progresses.
Otherwise, the rest of the forecast remains on track.
As of 650 PM Sunday...
Have reduced shower and thunderstorm chances this evening into
early tonight across much of the forecast area. Surface boundary
across the southern CWA is beginning to gradually lift north as
a warm front, but with little to no activity along the immediate
frontal boundary. Isolated showers persist across the northern
mountains north of the front, but should gradually exit within
the next couple hours. Do expect scattered showers and isolated
thunderstorms to fill in a bit throughout the overnight as the
front lifts northward and forcing becomes slightly more robust.
Minor tweaks to overnight temperatures and cloud cover were also
made. The rest of the forecast remains on track.
As of 158 PM Sunday...
A Flood Watch has been issued for portions of West Virginia,
southeast Ohio and northeast Kentucky from 06Z Monday through
02Z Wednesday. Multiple rounds of showers and thunderstorms will
impact the area, bringing rainfall accumulations of 1-3 inches.
Flash flooding is possible. In addition, prolonged heavy
rainfall may lead to river flooding.
___________________________________________________
Discussion
A stalled frontal boundary lies across central West Virginia
this afternoon, which has been the focus of showers and isolated
thunderstorms so far today. SPC currently has a marginal risk of
severe weather outlooked for Day 1 across the region. Recurrent
showers have kept the atmosphere stable so far today, but breaks
of sun across southern WV and northeast KY have allowed for
some limited instability to develop. At the time of this
writing, there is 500-1,000 J/kg of MUCAPE across southern WV,
with only about 250 J/kg of MLCAPE. Unless the low stratus deck
breaks up elsewhere, southern WV and northeast KY will probably
be the focus of any stronger storms later today, with the main
threats being isolated large hail and damaging winds.
The last few runs of the HRRR continue to show a wave of heavy
precipitation approaching southeast Ohio and northern West
Virginia by 06Z Monday morning, most likely associated with an
upper-level shortwave and a stalled frontal boundary at the
surface. Flooding downpours will be possible, which is why we
decided to issue the Flood Watch beginning at 06Z Monday.
There may be another lull in the precipitation midday Monday
before another wave of showers and thunderstorms approach from
the west in the late afternoon and evening associated with
another lobe of upper- level energy. By this point, the creeks,
streams and rivers across northern parts of the area may be
running a little high, so heavy downpours may lead to flooding.
In addition, the SPC also has another marginal risk of severe
thunderstorms across the region Monday afternoon and evening,
and the location of any severe weather will likely be wherever
there are breaks in the clouds during the day. Some models show
MLCAPE values as high as 1,000 J/kg across northeast Kentucky
and central to southern WV, along with 50-60 kts of sfc-6km
bulk shear. This would be sufficient for isolated thunderstorm
development, with the main threats being isolated damaging winds
and large hail.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 230 PM Sunday...
Key Messages:
* Severe thunderstorms possible Tuesday afternoon or evening.
* Multiple rounds of showers and thunderstorms may lead to
flooding or flash flooding Monday night through Tuesday
evening.
A frontal boundary will continue to oscillate across northern
portions of the region Monday night and Tuesday, pushing
northward in advance of waves and pushing back southward behind
waves. The cold front will finally push through Tuesday night.
This combined with instability south of the front will keep
chances of showers and thunderstorms over the area for Monday
night into Tuesday night. With the ground already saturated in
many areas from showers and thunderstorms today and Saturday,
and vegetation not out enough to absorb the water, flooding and
flash flooding become a concern. The main area of concern is
over Ohio, northeastern Kentucky and northern and central West
Virginia where the front will be most persistent and aid in
focusing the precipitation. Therefore, have issued a Flood
Watch for these areas through Tuesday evening.
There is also a concern for severe weather on Tuesday. The Storm
Prediction Center has covered the area in a slight risk, with
an enhanced risk over some of the region.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 1240 PM Sunday...
Key Messages:
* Accumulating snow for the higher terrain of the northern West
Virginia mountains Wednesday night into Friday. Headlines may
be needed.
Cooler air will move in behind the cold front for Wednesday. An
upper level low will continue to provide chances for precipitation
for Wednesday into Thursday, aided by some upslope flow. While
temperatures might not be cold enough for much more than a trace
of snow on Wednesday, even in the higher elevations, cooler
temperatures Wednesday night and Thursday should allow for an
inch or two of accumulation in the higher elevations every 6
hours. Little to no accumulation is expected in the lower
elevations due to warm ground temperatures.
The area will remain in a trough aloft as the upper level low
shifts into New England later Thursday into Friday. With
continued upslope flow and a couple of short waves moving
through the trough Thursday night and Friday, chances of
precipitation will continue. Once again, the higher elevations
of the northern mountains could see an inch or two every 6 hours
with little to no accumulation in the lower elevations.
A surface high pressure system will finally build in for
Saturday, with dry weather and a slight moderation in
temperatures.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
As of 815 PM Sunday...
VFR conditions persist across much of the area this evening,
with the exception being some MVFR CIGs in lower stratus across
the northern mountains. A warm front gradually lifts north
across the region early tonight, then becomes stationary across
portions of northern WV and southeast Ohio late tonight and
Monday. This results in ISOL/SCT showers and ISOL thunderstorms
later tonight and Monday across the region, with the highest
likelihood for rain being across the central/northern portion
of the forecast area. A few thunderstorms could be on the strong
side late tomorrow afternoon into the evening. CIGs lower into
MVFR late tonight and for Monday, with even IFR possible across
the northern terminals on Monday. MVFR VSBYs are likely within
showers, with brief IFR possible in heavier showers or any
thunderstorms. Given uncertainty in shower/thunderstorm
placement late tonight and Monday, prevailing VSBY restrictions
were left out of the TAFs for the most part for the time being,
as activity will generally be more confined near the frontal
boundary.
Light surface flow is expected tonight, generally S/SW for
locations south of the front, with E/NE for locations near or
north of the front. This trend continues on Monday, with a bit
of a breeze developing late tonight into Monday, resulting in
the occasional 15-25 kt gusts. Additionally, have coded in LLWS
for some locations later tonight into Monday morning as a low-
level jet quickly traverses the region.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...
FORECAST CONFIDENCE: Medium.
ALTERNATE SCENARIOS: Arrival and coverage of MVFR/IFR ceilings
may vary from the forecast based on location of the front.
MVFR/IFR VSBY restrictions are possible later tonight and Monday
within heavier showers or any thunderstorms (with the best
chance being central/north).
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 04/01/24
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10
CRW CONSISTENCY H H H H H H M M H H H M
HTS CONSISTENCY H H H H H M M M H H H M
BKW CONSISTENCY H H H H H H M M H H H H
EKN CONSISTENCY H H H H H H H H H H M H
PKB CONSISTENCY H H H L H H M M H L H H
CKB CONSISTENCY H H H M H H M H H H M H
AFTER 00Z TUESDAY...
IFR possible in showers and thunderstorms Monday night through
Tuesday night. IFR possible in snow in the higher elevations of
the northern West Virginia mountains Wednesday through Friday.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flood Watch from 2 AM EDT Monday through Tuesday evening for
WVZ005>011-013>020-026>032-039-040-519>526.
OH...Flood Watch from 2 AM EDT Monday through Tuesday evening for
OHZ066-067-075-076-083>087.
KY...Flood Watch from 2 AM EDT Monday through Tuesday evening for
KYZ101>103-105.
VA...None.
&&
$$
SYNOPSIS...RPY/GW/JMC
NEAR TERM...GW/JMC
SHORT TERM...RPY
LONG TERM...RPY
AVIATION...GW
Area Forecast Discussion
National Weather Service Blacksburg VA
922 PM EDT Sun Mar 31 2024
.SYNOPSIS...
A frontal boundary will remain in the area, helping to keep
scattered showers and thunderstorms chances through midweek.
Widespread rain looks most likely Tuesday into Wednesday, plus
rain and snow showers will linger over the mountains Wednesday
night, possibly through Friday. We remain well above normal for
temperatures through Tuesday, with cooler weather in the latter
half of the week.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 900 PM EDT Sunday...
Key Messages:
1. Trimmed probability of precipitation overnight
2. Greater chance for strong to severe thunderstorms Monday
afternoon and evening.
Wavy front still extended from the Mid Mississippi Valley
to along the Virginia/North Carolina border. Coverage of
precipitation will be limited overnight and mainly remain north
of this front. Have added areas of fog in for the rest of the
evening in the corridor that had rain Sunday afternoon.
Only minor adjustments to overnight lows based on current
observation trends.
Previous Discussion...
As of 2PM EDT Sunday...
Convective activity tracking ESEWD near and along a frontal
boundary slowly sagging southward has been overall lackluster
and has even lost most lightning activity as it crosses the
Appalachians. That being said, there is an axis of some
increased instability and there still remains an isolated threat
for some strong to severe development with decent deep layer
shear and cool thermal profile aloft. The northern half of the
CWA has largely been under a rather thick stratocu deck and with
a bit more stratiform precip currently tracking across from the
decaying previous approaching convection, the upstream
environment isn`t the greatest for redevelopment.
Should see a lull in precip for this evening into overnight,
then Monday looks to have a bit greater destabilization with
still decent deep bulk shear near 50-70 kts. HRRR neural network
probs are also greater so am weighing in on the isolated strong
to severe threat higher Monday. SPC has most of the CWA in a Day
2 Marginal Risk as well. Max temps Monday afternoon mainly nudging
up a few degrees higher than today so expect generally near 80
in the Piedmont and low to mid 70s in the mountains.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 130 PM EDT Sunday...
Key Messages:
1. Thunderstorms expected, with some possibly severe, late Tuesday
into Tuesday night.
2. High confidence for above normal temperatures, with minimum
temperatures Tuesday morning near or above record high values.
3. Gusty winds, upslope snow showers Wednesday into Wednesday night.
The deterministic medium range models are in good agreement that
upper level heights rise in advance of an anomalously deep upper level
and leading shortwave trof.
A cluster of showers and storms may be ongoing at the start of
Tuesday in the northern portions of our area as a strong low level
jet advects higher theta-e air over a nearly east-west oriented
stationary front expected to be positioned north of I-64. The track
of this complex of storms and amount of debris clouds will have a
significant influence on highs Tuesday. With most indicators,
including the ECMWF extreme forecast index for QPF, showing the axis
of heaviest rain falling north of our area, leaned toward the warmer
MET temperatures for highs on Tuesday, especially in the southern
portion of our region.
During the rest of the day on Tuesday, forecast soundings agree that
a fairly robust cap will be place, and lowered POPS from mid morning
to late afternoon. Winds should be brisk, especially across those
favored locations for strong southwest winds (Mercer/Tazewell
counties, where the GEFS shows 30-40% chance of gust reaching or
exceeding 40 MPH). After 21Z, better upper dynamics and the approach
of a cold front from the west should allow storms to enter the
western part of our forecast area. While the best combination of
instability and shear will be just to our west, there should easily
be enough forcing to allow storms to move into our area with a few
possibility severe, with damaging winds the main hazard.
As the front sweeps through early Wednesday morning, the best
instability and deepest moisture will be shunted east of our area by
12Z Wednesday, but expect scattered showers and some mountain snow
showers to linger Wednesday in advance of a deep upper level low.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 120 PM EDT Sunday...
Key Messages:
1. Confidence remains high for gusty winds and below normal
temperatures late this week.
2. Accumulating upslope snow showers possible Wednesday into
potentially Friday.
An anomalously deep upper level low should continue to influence our
weather through the long term period with an omega block pattern
expected to be in place. This will keep temperatures below normal
and bring a prolonged period of upslope snow showers, with the GEFS
showing greater than a 90% chance of 3" or more of snow along the
western slopes of West Virginia through at least Friday.
In the wake of the upper level trof axis sweeping through early
Thursday, impressive pressure rises and a deep mixing layer should
bring strong winds that forecast soundings suggest could exceed
advisory criteria, or stronger for the southern Blue Ridge. Will
continue to highlight this hazard in the HWO.
Leaned toward the cooler guidance for temperatures during this
period and confidence is high these values will be blow normal with
perhaps some moderation by Sunday.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
As of 155 PM EDT Sunday...
Wavy front still extended from the Mid Mississippi Valley
to along the Virginia/North Carolina border. Coverage of
precipitation will be limited overnight and mainly remain north
of this front. Have added areas of MVFR fog in for the rest of
the evening in the corridor that had rain Sunday afternoon. With
the surface dew points in the upper 40s to upper 50s, MVFR fog
may develop at local TAF sites, especially in locations with an
easterly component to the surface wind.
Showers and thunderstorms will redevelop in the Ohio Valley
Monday afternoon and track into the Mid Atlantic region after
18Z. Used the timing from the SPC HREF ensembles to add TEMPO
groups in the local TAFs. Some of the storms Monday afternoon
will have the potential to produce strong to damaging wind and
hail.
Average confidence for wind and ceiling.
Below average confidence for the extent of the fog and for the
timing of thunderstorms Monday afternoon.
EXTENDED AVIATION OUTLOOK...
Continued sub-VFR with showers and thunderstorms Tuesday and
Wednesday. Southwest winds will be gusty ahead of the front
Tuesday with even stronger northwest winds behind the system
Wednesday to Thursday.
A prolonged period of MVFR clouds and snow showers are expected
along the western slopes of the central Appalachians Wednesday
night through Friday.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...SH
NEAR TERM...AMS/AB
SHORT TERM...PH
LONG TERM...PH
AVIATION...AMS/AB
Area Forecast Discussion
National Weather Service Springfield MO
650 PM CDT Sun Mar 31 2024
.KEY MESSAGES...
- Enhanced risk for severe thunderstorms Monday evening through
Monday night. Large hail and damaging winds are the most
likely threats with less confidence in the tornado threat.
- While some thunderstorms could occur during the day Monday,
the highest severe storm chances are Monday evening after 6pm
as storms move west to east through the area.
- There is a localized flash flood risk Monday night. The
Weather Prediction Center has issued a Slight (2 out of 4)
risk for most of the area.
- Much cooler temperatures likely Tuesday through Thursday with
frost potential Wednesday and Thursday mornings.
&&
.SHORT TERM /THROUGH MONDAY/...
Issued at 130 PM CDT Sun Mar 31 2024
Synoptic Pattern and Current Conditions: Water vapor and upper
air analysis data shows the next impactful shortwave trough
across the western US. Both a Pacific and Gulf of Mexico
moisture stream could be seen moving through the southern US
and into the area. Strong warm air advection at 850mb along with
an elevated mixed layer/capping inversion was analyzed just
southwest of the area across southern Kansas and northeast
Oklahoma. Two areas of surface low pressure exist with one
across Colorado and another across central Kansas. A surface
warm front extended east of the surface low and was largely
located along I-70 in Missouri. Our area was solidly in the warm
sector with low 60 degree dewpoints and temps in the low to
middle 70s and this was even with partly to mostly cloudy skies.
A little muggy for the last day of March.
This afternoon - Tonight: Increasing inhibition/capping will
likely keep the area dry through this evening and most if not
all of the overnight hours. The exception will be areas along
and north of Highway 54 where enough lift closer to the front
and low level jet may allow for a few storms to graze those
areas before quickly lifting north of the area. Confidence in
this occuring is low and have kept precip chances less than 30%
Clouds will continue to stream in overnight and given the
continued south winds, temps will not fall far overnight. Many
locations will only drop into the middle to perhaps upper 60s,
especially west of Springfield. Areas east of Springfield
should fall into the lower 60s.
Monday Morning - Afternoon: Surface low pressure will
reorganize across southern Kansas/northern Oklahoma with the
frontal boundary largely remaining stationary well north/west of
the area. Deep southwest flow aloft will continue as energy
moves east into New Mexico and eventually Texas. While some
models show widespread precip across the area, we are cautious
with this scenario given several forecast soundings showing
strong capping aloft (CIN of 100-200j/kg). The exception will be
across central Missouri where capping is less. Latest 12z HREF
guidance suggests some elevated shower or thunderstorm
development could occur north of I-44 and east of Highway 65
during the late morning or early afternoon timeframe. IF, and
its a big IF, these storms form, they would likely be elevated
and given the amount of shear (0-6km shear around 50kts), large
hail up to the size of golf balls would be the main threat. The
time and spatial window of this looks small at this time.
Otherwise, very warm and humid conditions look likely with temps
rising into the 70s given continued warm/moist advection. Any
cloud breaks would allow for temps to reach 80, perhaps west of
Springfield.
Monday evening - Monday Night: This is the timeframe of concern
as the upper level lift increases and noses into the area (120kt
300mb jet and a 70-80kts 500mb jet). The surface low and front will
slide east during the late afternoon and evening. Latest HREF
and NBM instability probs have increased and confidence is now
high that between 500-1000j/kg of ML CAPE will be available for
evening thunderstorms. A few CAMS even show instability closer
to 1500j/kg. Mid level lapse rates have also come in more steep,
especially in the 800-500mb layer. Wind shear will be more than
adequate with 0-6km shear around 50-70kts. Forecast soundings
from the RAP indicate a weakening cap by Monday evening from
southeast Kansas into western Missouri. HREF paintball plots
show high coverage of storms to develop in this area, likely
with a few supercells in the begnning with large hail, damaging
winds and tornadoes all being possible. Large hail over 2
inches in diameter would occur with any supercells that form
initially however the large hail parameter decreases drastically
by mid to late evening as storms begin to form clusters or line
segments.
These clusters or line segments then look to move east through
the area with a large hail and damaging wind threat. Low level
CAPE of at least 40j/kg and 0-3km shear over 40kts would support
QLCS tornado development with any bowing segments to the
northeast. Confidence in the tornado threat should increase as
we get closer to the event. However these setups are often
times very complex, messy and may not be resolved by models
until 3-6 hours before the event begins therefore additional
updates are likely as we get closer. Stay up on the latest
forecasts from SPC. There are some CAMS that are later with the exit of
this system (after midnight) however the highest chances of
severe weather appear to be prior to midnight.
While there does appear to be a flooding threat, it looks
localized given the potential for a more progressive cluster of
storms. If thunderstorms can train over the same areas then
flash flooding could occur given high rainfall rates as PW
values climb into the 1-1.2in range. The HREF mean qpf forecast
shows the highest chances for training storms and 1-2 inches of
rainfall to be north of Interstate 44 and perhaps even north of
Highway 54 closer to the front.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 130 PM CDT Sun Mar 31 2024
The shortwave trough will be slow to move through the area on
Tuesday therefore a cloudy and cool day is expected with even
some morning rain showers. Cold air advection will be strong and
NBM guidance suggests temps will struggle to warm through 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 for the weekend. A dry airmass and increasing winds could
lead to areas of elevated fire danger east of Springfield late
in the week. There is not a signal for precipitation until
perhaps late in the weekend however significant variance exists
in model guidance.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 645 PM CDT Sun Mar 31 2024
Broken to overcast middle to high cloud cover will remain over
the region this evening. Occasional periods of MVFR ceilings
will be possible as moisture in the lowest 5kft increases
overnight. Surface winds will remain southerly and gusty.
A front will approach the region from the east Monday afternoon
with increasing chances for showers and thunderstorms.
&&
.CLIMATE...
Issued at 130 PM CDT Sun Mar 31 2024
Record High Temperatures:
March 31:
KVIH: 84/2010
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...Hatch
CLIMATE...Burchfield
Area Forecast Discussion
National Weather Service Las Vegas NV
214 PM PDT Sun Mar 31 2024
.SYNOPSIS...Scattered showers and isolated thunderstorms expected to
develop this afternoon and evening across the forecast area. A few
showers may linger into Monday before warm and dry conditions take
over through midweek. Gusty winds, a drop in temperatures, and the
return of precipitation chances expected late-week into the weekend
as the next storm drops into the Desert Southwest.
&&
.SHORT TERM...Today through Wednesday.
The mostly clear skies across the Mojave Desert this morning have
eroded as scattered showers and isolated thunderstorms form across
the region. The HRRR forecast reflectivity supports a band of
convection pushing southward through central Nevada and into the
southern Great Basin this afternoon. This supports the idea that
convection will occur along the deformation zone between the low
pressure center in northern Utah and the low center off the coast of
Baja California. Modest instability will result in isolated
thunderstorms that will result in locally heavier precipitation.
With cooler temperatures in place than yesterday, this reinforcing
band of precipitation is the justification for the remaining Winter
Weather Advisories in Esmeralda, central Nye, and Lincoln counties
today. Otherwise, precipitation amounts should be relatively low,
with totals remaining below 0.10 inches of rain in the valleys and
below 3 inches in the mountains.
As this system continues to push eastward out of the area, remnant
instability and moisture will result in isolated shower activity on
Monday across the eastern Mojave Desert, though skies will clear
west-to-east throughout the day. Ridging will extend northwestward
across the Desert Southwest from a Pacific high. Resultant tightened
pressure gradients will enhance gusty north winds along the Colorado
River Valley on Tuesday, with light afternoon breezes expected
elsewhere. Temperatures will warm to a few degrees above-average as
heights rise over the Desert Southwest through midweek.
.LONG TERM...Thursday through next Sunday.
Another incoming weather system will produce strong, gusty south-
southwest winds across the forecast area Thursday afternoon. The
associated cold front will be fairly potent, with a forecast
temperature drop of almost 20 degrees between Thursday and Friday
afternoon.
20-40% PoPs increase across the southern Great Basin and northern
Mojave Desert Thursday and Friday as the center of the low moves
overhead. As mentioned in the previous discussion, rain amounts will
be dependent on the trajectory of this low and subsequently, how
much moisture is pulled into the region. Details will become more
clear as we move through the week.
&&
.AVIATION...For Harry Reid...Breezy southwest winds with gusts to
around 20 knots will develop by early afternoon and persist through
this evening before diminishing after dark. Showers are possible in
the Las Vegas Valley vicinity with A ~20 percent chance of rain at
the terminal. Shower activity may briefly result in locally erratic
wind gusts and CIGS to around 6kft AGL. Clearing conditions expected
overnight but additional showers will be possible Monday with
northerly surface winds favored.
For the rest of southern Nevada, northwest Arizona and southeast
California...South or southwesterly breezes are favored for most of
the regional TAF sites within the Mojave Desert through this
afternoon along with scattered shower activity and CIGs in the 5-
7kft AGL range. An isolated thunderstorm can`t be completely ruled
out either with gusty and erratic surface winds. Further north, more
numerous showers and isolated thunderstorms are expected near KBIH
with gusty north winds possible. Precipitation will taper off
overnight with winds diminishing...though isolated shower activity
will again be possible Monday.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
DISCUSSION...Varian
AVIATION...Outler
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