Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/14/24
Area Forecast Discussion
National Weather Service La Crosse WI
1036 PM CDT Mon May 13 2024
.KEY MESSAGES...
- Smoke from Canadian wildfires continue to impact the local
area with hazy conditions/milky skies tonight.
- Rain chances linger far south tonight and Tuesday, much drier
air to move in from the north.
- Rain chances favorable, but still light (50-70% chance of
0.10+) Wednesday night into Thursday with the weekend still
unsettled for now.
&&
.DISCUSSION...
Issued at 224 PM CDT Mon May 13 2024
Overview:
Water vapor satellite imagery, 500mb heights, and lightning
showed a closed low over the Mid-Missouri River Valley with
another area of closed low pressure over Hudson Bay. Lightning
was noted over parts of IA/MO into IL, with clusters of storms
farther south across TX/LA/MS/AL. The first surface front was
over parts of northern IL with a reinforcing push/wind shift
moving through as the wave to the northeast pushes through with
dewpoints in the 30s pushing south and dewpoints in the 50s to
around 60 lingering across parts of eastern Iowa and southern
Wisconsin.
Smoke Tonight - Rain chances tonight/Tuesday:
Visible satellite imagery from 13Z this morning showed an expanse of
smoke across the local area, however by 15Z, local visibilities had
improved some. Hazy conditions with some visibility reductions will
be possible into the overnight hours. The latest RAP Near-
Surface Smoke forecast shows a north to south push of improving
conditions. By 06Z, parts of northeast Iowa and the PDC area
could see some reduced visibilities. Some low values of
particulates will linger area-wide 14.09-16.00Z Tuesday. Air
quality alert for parts of MN/WI/IA remain in effect this
evening.
The trough over the Upper Mississippi Valley phases with the mid-
tropospheric low over the Mid-Missouri River Valley, but then closes
off again off over IL shifting east through the day Tuesday.
Showers and a few storms will continue to graze parts of the
southern forecast area today, then a few showers will persist
until the storm system shifts east into Tuesday. The general
consensus with the hi-res models is for the bulk of the activity
to remain southeast of the forecast area Tuesday. The 13.12Z
HREF was a bit farther south with the precipitation compared to
the 13.00Z run. The RAP is a little more aggressive farther
north. For now will hold on to some pops in the south and
monitor push of drier air and northward extent in the short
term.
Temperatures Tuesday and Wednesday should be seasonable in the 60s
to lower 70s.
Rain chances mid to late week:
The trough over the Pacific Northwest is forecast through the Plains
Tuesday night toward the Upper Mississippi Valley Wednesday night.
The low level jet increases and 850mb moisture pools ahead of the
cold front from MN/wrn IA/ern KS Wed. Moisture transport increases
locally Wednesday night into Thursday. Deepest moisture and
stronger moisture transport vectors remain to the south across parts
of MO/IL. There appears to be enough vorticity/warm air advection
and limited instability (500J/kg) with the front for scattered
showers and a few storms. 0-6km is generally limited...20-30kts,
however there is a period of time Wednesday night with higher shear
values north of I94, however instability is quite low then. Will
maintain likely shower/storm chances Wednesday night into Thursday.
Forecast soundings hint that a few showers could re-develop
Friday/Friday night in the northwest flow aloft.
For the weekend, we are still unsure of if the pattern will be more
zonal locally or have a trough coming through. Due to this
uncertainty of dry vs. a trough and timing differences, we do
have rain chances in for the weekend, but this will be refined
as we hone in on the synoptic patern. The NAEFS/EFI remain on
the lackluster side. Weekend temperatures appear to be
seasonably warm in the 70s.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1037 PM CDT Mon May 13 2024
VFR conditions are expected through the TAF period with some high
cirrus and some smoke aloft. Any remaining surface smoke will move
out of the region early in the TAF period with increasing easterly
surface winds into the morning and afternoon hours to around 10
kts. A disturbance passing to our south may bring in a shower
or two into portions of northeast Iowa and southwestern
Wisconsin overnight and into the morning hours on Tuesday
however both TAF sites are expected remain dry. Winds will begin
to diminish during the evening on Tuesday to around 5 kts as
diurnal mixing begins to wane.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Zapotocny
AVIATION...Naylor
Area Forecast Discussion
National Weather Service Denver/Boulder CO
808 PM MDT Mon May 13 2024
.KEY MESSAGES...
- Scattered showers and isolated thunderstorms over the mountains
and foothills with isolated showers and storms over the nearby
plains.
- Scattered afternoon/evening showers and thunderstorms Tuesday.
- Front brings cooler and wetter weather on Wednesday. Light snow
for elevations mainly above 10,000 feet.
- Warmer and generally drier starting Thursday, with lesser but at
least isolated daily afternoon showers/thunderstorm coverage,
highest for the mountains.
&&
.UPDATE...
Issued at 802 PM MDT Mon May 13 2024
A few showers are still lingering across the high country and
eastern plains, but it`s generally a quiet evening. Showers should
diminish through the rest of the evening although a snow shower or
two will remain possible overnight across some of the northern
mountains. No significant changes to the previous forecast were
made as it was in good shape.
&&
.SHORT TERM /Through Tuesday/...
Issued at 217 PM MDT Mon May 13 2024
Radar showing scattered showers over the mountains and foothills.
Best instability resides over the higher terrain with ML CAPE to
around 500 J/kg, so still expect isolated storms to form.
Instability decreases eastward onto the plains. Weak ridging will
move across Colorado this evening and tonight. Expect this to keep
convection weak and isolated to scattered. The stronger storms
will be capable of produce small hail (pea sized), wind gusts to
40 mph, and brief heavy rain. Convection dies off early to mid
evening with the loss of daytime heating stabilizing the airmass.
For Tuesday, westerly flow aloft will prevail behind the exiting
ridge and in advance of a wave dropping southeast across Wyoming.
This wave should help produce at least scattered convection (more
than today). Instability will slightly increase with ML CAPE up to
700 J/kg. Still expect storms to stay sub severe, with brief
heavy rain and small hail under the stronger storms. Wind gusts
may be slightly stronger, up to 50 mph. Airmass warms a little
more with some locations topping 80F degrees over northeast
Colorado.
&&
.LONG TERM /Tuesday night through Monday/...
Issued at 217 PM MDT Mon May 13 2024
Tuesday evening into Wednesday, an upper level trough approaches
from the west with weak QG lift ahead it. An associated cold front
moves across the region, likely early Wednesday morning (midnight-
6am). North to northeasterly flow persists during the day Wednesday
post-front. The upslope component will provide an addition source of
moisture, especially in the favored areas such as the Palmer Divide,
Front Range, and adjacent plains. This will bring a cooler and more
unsettled day. In the cooler post-frontal airmass, high temperatures
likely stay in the 60s across the plains, considerably cooler than
Tuesday`s highs. Sounding profiles and instability fields show
marginal instability Wednesday afternoon (MLCAPE < 500 J/kg). Within
the weak upslope environment, this could support convective showers
and embedded storms.
With respect to amounts, ensemble means show a range of 0.20" to
0.60". There is notable small variations happening from run to run
and the GFS is appearing to be the wetter suite of solutions. The
higher amounts will likely be focused in those upslope favored
areas (Front Range, Palmer Divide, south foothills, Denver metro).
The cooler air stays north with the trough, but it be should
enough to bring snow levels down to 10,000 during the day and
around 9500 overnight. As a result, snow showers are possible for
the higher mountains/mountain passes. Ensembles show light
accumulations, so at this point not major impacts are anticipated.
On Thursday, the upper trough exits to the east putting northeast
Colorado under northwesterly flow aloft. Subsident flow should keep
dry out much of the region from Wednesday. Model cross sections show
some residual moisture in the high country with marginal instability
building in the afternoon to support scattered showers/storms. Given
the limited instability/moisture, coverage/chances will be less (<
25%) and mainly over the higher terrain. Temperatures recover from
Wednesday with highs pushing back into the upper 60s/low 70s for the
lower elevations and 40s/50s for the high country.
Friday into the weekend, expect weak ridging to zonal flow in the
upper level pattern. 700mb temperatures warm a degree or two each
day, supporting a gradual warming trend. Highs in the upper 70s to
low 80s Fri/Sat. Daily heating/instability should support scattered
afternoon showers and thunderstorms in the mountains with a low
chance for a few to stray onto the adjacent plains. Friday through
the weekend will be drier across the plains with relative humidity
values dropping into the 20 percent range in the afternoons.
&&
.AVIATION /00Z TAFS through 00Z Tuesday/...
Issued at 533 PM MDT Mon May 13 2024
Generally VFR through the TAF period. In the near term, main
concern is an outflow boundary draped fro GXY to just east of DEN
which is slowly drifting west. Speeds on either side of this
boundary aren`t terribly strong, but if any showers/TS form in the
next hour or two it would likely be on this boundary. The HRRR
does hint at another round or two of organized showers later this
evening but confidence in that is fairly low.
Drainage flow is expected overnight tonight, followed by a turn to
the northwest by tomorrow afternoon. Additional widely scattered
storms are possible tomorrow afternoon. Model consensus supports
this being isolated enough to not include a PROB30/TEMPO at this
point.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Hiris
SHORT TERM...Meier
LONG TERM...Mensch
AVIATION...Hiris
Area Forecast Discussion
National Weather Service Burlington VT
1029 PM EDT Mon May 13 2024
.SYNOPSIS...
An unsettled weather pattern will continue over the next couple of
days with several rounds of showers, with numerous showers and some
embedded thunderstorms expected tomorrow. Seasonable high
temperatures and mild overnight lows are expected for much of the
upcoming week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 1030 PM EDT Monday...Forecast remains in good shape so
only made minor tweaks to bring it up to date with current obs.
Warm front is lifting northward across NY state this evening,
helping to fuel a few showers with a few cloud flashes and even
a solitary lightning strike across far western St Lawrence
county. But lightning activity is not expected to make too much
eastward progression, as the embedded shortwave energy will be
steered northeastward roughly parallel to the St Lawrence River
valley. RAP mesoanalysis shows height rises associated with a
H5 ridge east of the Adirondacks into Vermont. One favorable
parameter is the 2-6 km AGL lapse rates, which are in the 6.5 to
7C/km range. But the expectation is that outside of northern NY
which has the best chance of hearing a few rumbles of thunder,
our Vermont zones should primarily see rain showers with the
isolated brief downpour. Temperatures will be slow to fall
overnight thanks to strong warm advection and southerly flow.
PREVIOUS DISCUSSION...Light showers across the region have
brought little to no measurable precipitation this afternoon,
with only a few hundreths at most so far. As we head into the
evening, a frontal boundary will become stalled near the
International Border, with increased chances for showers and
some possible rumbles of thunder across northern New York
overnight due to increased elevated instability and stronger
forcing. Overnight lows will be on the mild side tonight, in the
50s, although spots east of the Greens will drop into the upper
40s.
Model soundings for tomorrow show tall and skinny CAPE profiles,
supporting the idea of some heavy downpours and embedded
thunderstorms tomorrow afternoon, with PWAT values in excess of an
inch. Current QPF amounts range from a few tenths to near an inch,
with localized higher amounts expected in any thunderstorms. The
latest CAM guidance suggests CAPE values between 500 to 1200 J/kg
across southern portions of the forecast area tomorrow, with
temperatures warming into the 70s. Meanwhile closer to the
International Border, temperatures will only warm into the upper
60s. There is still a little uncertainty regarding the instability
across the region tomorrow afternoon as lingering cloud cover will
limit surface heating. There is the potential for training storm
motions with any developing convection, which will need to be
monitored given the potential for heavier downpours. While
widespread severe is not currently anticipated, NCAR is showing a
non-zero threat for some severe weather and there will likely be
plenty of activity to monitor tomorrow afternoon. Shower activity
will dwindle heading into the evening with the lack of diurnal
heating, with overnight lows expected to be quite mild for this time
of year.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
As of 402 PM EDT Monday...ANother round of showers is expected for
much of Wednesday as a cut off low becomes stuck over the Mid-
Atlantic region. This slow moving low pressure system is expected to
drape a warm frontal boundary across our forecast area which should
allow for shower activity to increase throughout the day on
Wednesday given modest heating under cloudy skies. Thermal profiles
have varied from run to run but it seems we will be looking at
closer to moist adiabatic lapse rates which in this case likely
won`t favor thunderstorms. Could a rumble of thunder occur?
Possibly, but most likely we should just see scattered to numerous
showers on Wednesday. The main focus on rainfall accumulations will
be across southern Vermont where we could see a quarter to maybe a
third of an inch of rain but lesser amounts as you get closer to the
International Border. Shower activity is expected to wane as we head
into Wednesday evening with the loss of daytime heating but a few
showers will likely continue through the overnight period.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 402 PM EDT Monday...Thursday had been looking drier for a while
but the latest guidance suggests it may not be as dry as we had been
thinking. The stall frontal boundary mentioned in the above section
will remain over the area on Thursday. We better heating due to
slightly less cloud cover, a resurgence of shower activity is
expected during the afternoon hours. It won`t be as widespread as
Wednesday but isolated to scattered showers could drop some light
rain throughout the day with thunderstorm potential again looking
rather meager. Friday, on the other hand, has trended a little drier
as the 12Z guidance is showing building 500 mb heights in response
to a deepening trough over the central US. Increasing subsidence is
expected to keep shower activity largely at bay although a few
diurnal showers cannot be ruled out.
Rain chances will increase throughout the day on Saturday as the
aforementioned trough slides eastward and we see a series of frontal
boundaries move through the region. With good fetch of Gulf of
Mexico moisture, we could see some heavy rain showers this weekend
but the details will be ironed out over the next several days. Those
with outdoor weekend plans are encourages to keep a close eye on the
forecast. This period of unsettled weather is likely to continue
well into next week with a series of disturbances likely to pass
near the northeastern US. The good news is that we aren`t expecting
any significant rainfall so flooding doesn`t look to be a concern
moving forward.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wednesday...Mainly VFR conditions are expected for
the next few hours. Winds throughout the period will range
between southeast to southwest between 5 and 10 knots through
the period, with a few gusts 15 to 18 knots at KBTV. Some
showers are already present over northern New York and did
produce some lightning, but have been decaying. The stronger
convection is north of Lake Ontario, and that will shift into
the region alongside the warm front about 02z to 03z. Showers
will be likely across the region between 03z and 10z as it lifts
north and then stalls near the international border. In heavier
elements, 3-6SM visibility and ceilings 2000-3000 ft agl will
be possible. Thunderstorm activity should decay moving east, and
so KSLK is the only to have a TEMPO for TSRA between about 03z
and 05z, but could be possible further east if it holds
together. Patches of low level wind shear will develop behind
the warm front from about 04z to 10z for 35 to 40 knot southwest
winds at 2000 ft agl.
Some partial clearing and lifting ceilings follow the warm front
10z-12z, but where warm front stalls is not entirely certain.
So outside of KMPV and KRUT, the forecast maintains VCSH for
several terminals. Additional showers and thunderstorms will
develop about 18z. A weak trough will shift south, with
convection near the trough and lifting north-northeast towards
the trough axis until is passes south sometime near or after 00z
Wednesday. It`s too far out now, but some thunderstorms could
be strong, and there will be potential for ceiling and
visibility reductions between 18z beyond 00z Wednesday.
Outlook...
Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA.
Wednesday: Mainly MVFR, with local VFR possible. Likely SHRA.
Wednesday Night: Mainly VFR, with areas MVFR possible. Chance
SHRA.
Thursday: Mainly VFR, with local MVFR possible. Chance SHRA.
Thursday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Friday: VFR. Chance SHRA.
Friday Night: VFR. Chance SHRA.
Saturday: Mainly MVFR, with local IFR possible. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Kremer
NEAR TERM...Chai/Kremer
SHORT TERM...Clay
LONG TERM...Clay
AVIATION...Haynes
previous forecast discussion mentioned, instability and shear will
be very marginal, with effective shear values progged around 20
knots or less, with HREF surface based CAPE up to 1000 J/kg this
afternoon. Given this parameter space, severe storms aren`t
expected. However, with Pwat values hovering around 1.2 to 1.4,
which is near or above the 90th percentile off the SPC sounding
climatology, periods of heavier rainfall are expected. A deformation
zone appears to develop north of the cut-off low, and pivot across
our southern forecast area. Slow moving or repeated rounds of
showers and storms would allow rainfall to accumulate rapidly, so we
will continue to watch for flooding issues. WPC continues to paint a
Slight risk of flash flooding for areas along and south of
Interstate 80. In total, between 1 to 2 inches of rainfall remains
possible for areas along and south of I-80, with gradually lighter
amounts farther north. HREF localized probability-matched mean
indicates some isolated areas could see between 2 to 3+ inches of
rainfall, given the higher Pwat values.
As we go into Tuesday, the deformation band is expected to weaken
with time, but it won`t move a whole lot, so showers will continue
to linger across our southern forecast area. Eventually, the upper
low will move off to the east by late in the day Tuesday, which will
bring any lingering showers to an end and lead to decreasing cloud
cover from the northwest. One other thing to watch for, especially
in the afternoon hours Tuesday, is the potential for some Canadian
wildfire smoke to filter in from the north. Air Quality Alerts have
been issued for areas of northern Iowa into Minnesota and Wisconsin.
The HRRR Smoke model shows a smoke plume dissipating as it filters
into our region, but the impacts from this smoke are expected to
be little, if any, at this time.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 221 PM CDT Mon May 13 2024
The long-term period starts off with dry conditions for Tuesday
night through Wednesday, thanks to an area of high pressure nosing
into the region from Ontario Canada. Temperatures will be seasonal
for this time frame, with lows Tuesday night in the middle to upper
40s, and highs Wednesday in the lower to middle 70s.
The next chances of widespread showers and storms returns for
Thursday as an upper-level trough translates eastward across the
central Intermountain West region. A southern stream mid-level
impulse is progged to lift northward towards our region, and bring
widespread chances (40 to 70% from the NBM) of rainfall. Pwat values
of around 1 to 1.3 inches are progged off the deterministic GFS and
NAM guidance, so another round of decent rainfall is possible
Thursday, although NBM probabilities of total rainfall of a quarter
inch or greater is between 40 to 60 percent, so not a strong signal
either way. At this time, the threat for any strong to severe storms
Thursday remains low, given meager values of effective shear and
instability.
The upper-level pattern continues to be active into the end of the
week, with additional upper-level troughs traversing the northern
CONUS, but confidence in the timing of these troughs for our area
remains uncertain due to differences in the guidance.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 618 PM CDT Mon May 13 2024
VFR conditions will quickly transition to MVFR and IFR through
the evening and night. Widespread showers and thunderstorms are
being seen throughout, which are actively lowering cigs and vis
throughout, continuing through the night. Currently, cigs are
forecast to drop into the 1000-3000 ft range before 06z, with
cigs dropping below 1000 ft after. These conditions will persist
through the night, as the low pressure slowly moves through the
area. The lowest cigs will be seen in heavier showers and
storms, which may drops cigs to 500 ft or less briefly.
Confidence is low on this though. Vis will also be a concern,
but mainly in the heavier showers/storms. These conditions will
prevail through 12z, waning away around 18z and beyond.
Although, the low cigs will remain through much of the TAF
period. Main hazards with these storms will be lightning and
non-severe wind gusts, with small hail being secondary.
Surface winds are currently variable, but will mostly be out of
the east-northeast through the night and into tomorrow. The
winds will be relatively light through the night, increasing
after 12z, with gusts upwards to 20 KTs possible tomorrow.
&&
.HYDROLOGY...
Issued at 221 PM CDT Mon May 13 2024
New forecasts by the North Central River Forecast Center this
evening showed little to no change for the Wapsipinicon River
near DeWitt. The river should reach flood stage before 7am
tomorrow morning and slowly rise to 11.4 feet over the next 3
days. Depending on where additional rain falls this afternoon
into this evening, more rises may be possible. However, at this
time the highest totals are expected south of the Wapsi basin.
The Flood Warning was continued with this forecast issuance.
The forecasts for the Cedar and Iowa Rivers have come in lower this
morning. The Cedar River near Conesville forecast was kept just
at flood stage for now due to the incoming QPF uncertainty. For
this reason, have kept the Flood Watch going there.
Flood Watches have been issued for the Mississippi River at
Gladstone and Burlington due to routed flow as well as rainfall
amounts forecast through Tuesday.
Taking a deeper dive into the QPF, widespread rainfall in the 0.5"
to 1.5" range is expected in the next 24 hours, with some
localized higher amounts. The 12z HREF probability-matched mean
QPF values through Tuesday morning are painting a swath of
rainfall in excess of one inch, with some isolated amounts over
two inches slightly northward closer to the downstream portions
of the Iowa, Cedar, and Mississippi River basins. This QPF
placement and how much runoff occurs will be very important to
whether additional rises are seen and if warnings will be
needed.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Schultz
LONG TERM...Schultz
AVIATION...Gunkel
HYDROLOGY...Cousins
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
653 PM CDT Mon May 13 2024
...New UPDATE, AVIATION...
.UPDATE...
Issued at 653 PM CDT Mon May 13 2024
Isolated showers and thunderstorms have re-developed early this
evening across Kerr and northern Medina counties, along a weak
surface front and close to where where recent HRRR runs were
indicating. A few WoFS members are showing isolated convective
development along this boundary over the Hill Country over the next
hour. The HRRR and WoFS dissipate activity after sunset.
&&
.SHORT TERM...
(Tonight through Tuesday night)
Issued at 207 PM CDT Mon May 13 2024
The ongoing cluster of storms across the CWA, associated with a mid-
level shortwave, will continue to push east through the afternoon.
The current storm mode now favors more of a wind threat compared to
hail, though severe hail will still be possible, especially with the
more discrete updrafts. While more uncertain, there remains
potential for additional development along the surface
front/boundary currently extending from just south of Del Rio
northeastward through the northern Hill Country. This boundary is
unlikely to move much farther to the S/E this afternoon, but will
serve as a weak lifting mechanism. This is evident already between
Val Verde and Kerr County where there have been attempts at
convection on satellite imagery and radar. Where exactly any new
development forms later this afternoon and evening, if any, is the
the big question, though the HRRR seems to favor the Hill Country
into northern portions of the I-35 corridor. Working against this
however would be the widespread cloud cover in place and rain cooled
air. Regardless, if any storms do form, the severe threat will
remain with the CAPE and shear in place. As far as the plan for the
Severe Thunderstorm Watch, it can likely be dropped once the cluster
of storms pushes east as any additional activity should be isolated.
However, this is not set in stone and will continue to be re-
evaluated through the afternoon.
Otherwise, dry conditions are expected overnight and through the end
of the short term period. Some models are indicating potential for
patchy ground fog forming early tomorrow morning, which makes sense
given the rainfall today and light surface winds in place. Any
fog/low clouds should quickly burn off after sunrise, with mostly
sunny skies expected for the remainder of the day and temperatures
warming into the upper 80s to upper 90s.
&&
.LONG TERM...
(Wednesday through Monday)
Issued at 207 PM CDT Mon May 13 2024
A west coast trough is still expected to arrive later in the work
week, though timing may be slightly delayed from forecasts issued
over the weekend. The best rain chances from this system are now
expected mainly on Thursday and possibly lingering through the day
on Friday. Due to the changes in model guidance and the the
potential for widespread rainfall across the southern Plains, the
extent of the severe weather threat remains unclear. However, given
the time of year, at least an isolated severe threat seems plausible
as we get closer in time in addition to the potential for locally
heavy rainfall.
We will then trend drier and warmer over the weekend and into the
beginning of next week with temperatures likely becoming several
degrees above normal. Just beyond the end of the long term,
deterministic guidance shows another trough moving into the Plains,
but with a more northerly trajectory compared to the system late
this week.
&&
.AVIATION...
(00Z TAFS)
Issued at 643 PM CDT Mon May 13 2024
VFR conditions will prevail across most of south central Texas
tonight and Tuesday. The only exception will be in any isolated
SHRA/TSRA activity through sunset along a weak cold front across the
Hill Country as well as 09Z-14Z across portions of the Hill Country
and east of the I-35 corridor where patchy BR and low stratus produce
IFR to MVFR conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 64 92 66 91 / 20 0 0 0
Austin Bergstrom Intl Airport 62 90 64 90 / 20 0 0 0
New Braunfels Muni Airport 63 92 64 92 / 20 0 0 0
Burnet Muni Airport 62 88 66 90 / 20 0 0 0
Del Rio Intl Airport 68 100 72 98 / 0 0 0 10
Georgetown Muni Airport 62 88 65 89 / 20 0 0 0
Hondo Muni Airport 62 93 65 92 / 10 0 0 0
San Marcos Muni Airport 62 90 64 91 / 20 0 0 0
La Grange - Fayette Regional 64 88 65 90 / 20 0 0 0
San Antonio Intl Airport 64 92 66 91 / 10 0 0 0
Stinson Muni Airport 64 93 66 93 / 10 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...Gale
Long-Term...Gale
Aviation...76
Area Forecast Discussion
National Weather Service Hastings NE
633 PM CDT Mon May 13 2024
.KEY MESSAGES...
- Showers and thunderstorms will be possible Tuesday afternoon
through Wednesday night. Severe thunderstorms are generally not
expected.
- Temperatures will be pleasant through Thursday with highs in
the 70s. Temperatures will be warmer Friday through the
weekend with highs in the 70s and 80s, with highs Saturday
potentially approaching 90 degrees across most of the area.
- Off and on chances for thunderstorms exist across the area
through the period, with the best chances for this occurring
(beyond Wednesday) being over the weekend.
&&
.DISCUSSION...
Issued at 200 PM CDT Mon May 13 2024
An area of low pressure exists along the KS/MO border this
afternoon. A few showers and isolated thunderstorms rotating
around the low continue to impact mainly southeast portions of
the forecast area, but these will depart as the low continues
east into Missouri this afternoon and evening.
Tonight and Tuesday...
High pressure will briefly move over the area, even as a front
begins to move into the northern and central Plains. Overnight
lows tonight will be in the 40s. This evening and overnight,
with light winds across the area, RAP and HRRR model guidance is
showing a little bit of smoke from Canadian wildfires moving
down into Nebraska...while most of this will remain over
northeastern portions of the state, some of this may drift over
northern and far eastern portions of our forecast area. This
probably will not impact the surface too much, but you may
notice some haze in those areas Tuesday. With winds becoming
south to southeast Tuesday and a ridge in place, trended high
temperatures toward the higher side of forecast
guidance...especially west of Highway 281 where southerly winds
of 15 mph or greater are favored. With that, high temperatures
are forecast to range from the upper 70s to the low 80s.
Tuesday night through Wednesday night...
Showers and thunderstorms are expected to return to the forecast
area late Tuesday afternoon through Wednesday night. Although
overall any thunderstorms are not expected to be severe, with
increasing deep layer shear and marginal instability going into
Tuesday evening, cannot rule out an isolated strong to severe
thunderstorm early on in this event (late Tuesday afternoon into
Tuesday evening)...so while there is a low chance of this
occurring, we could see a sneaky storm with some hail to nearly
quarter sized west of Highway 281 right along the frontal
boundary...but anything approaching severe should be limited to
just that. As far as rainfall amounts, even with pretty high
PoPs (50-70%), QPF values remain low, around 0.25" or less in
most places.
Thereafter...
A weak broad upper trough will be present over the central
Plains Thursday and Friday, bringing low chances (< 20%) of
showers and storms to the area. High temperatures will be in the
70s Thursday and in the 80s Friday. We have slightly better
chances of storms in the forecast (20-35%) this weekend, but
deterministic and ensemble models diverge a good bit this far
out. Ensembles seem to have a better handle on temperatures
Saturday, with two-thirds of the ENS and GEFS ensemble members
settling on highs in the 80s across the area.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 630 PM CDT Mon May 13 2024
VFR conditions are expected for the next 24 hours. Winds will be
out of the northeast to northwest through 12z then switch to the
east to southeast around 15z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
DISCUSSION...Hickford
AVIATION...Schuldt
Area Forecast Discussion
National Weather Service Goodland KS
536 PM MDT Mon May 13 2024
.KEY MESSAGES...
- Smoke from Canada may impact the Tri-State area through
Tuesday. Those with respiratory concerns are encouraged to
keep a watchful eye on air quality levels.
- Summer-like temperatures are expected Tuesday, with widespread
80s expected.
- Periodic chances for showers and thunderstorms are expected
Tuesday/Wednesday and again Saturday/Sunday.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 247 PM MDT Mon May 13 2024
For the rest of this afternoon, an upper trough will continue
to move to the east, with the western part of the Tri-State area
coming under northerly flow. Expected afternoon high
temperatures will be primarily in the 70s. Visible satellite
imagery shows a few cumulus clouds moving across the region.
There is a small, non-zero chance of an isolated shower or
thunderstorm popping up this afternoon in the eastern part of
the area. Northerly winds have been transporting smoke from
fires in Canada into the region. Those with respiratory concerns
will want to be mindful of conditions over the next day and a
half as the HRRR shows the potential of smoke staying in the
region.
Tuesday, northwesterly to westerly flow will be set up over the
region. Expected high temperatures will be reminiscent of early
summer, reaching the low to mid-80s across most areas. At least
for the morning hours, dry conditions are expected. There will
also be a chance of some smoke from Canada impacting the area.
Heading into the afternoon, an upper trough drops south into
northern Utah and Colorado. There will be a chance for showers
and thunderstorms beginning in the afternoon. At this point in
time, severe weather is not anticipated.
Tuesday evening, a cold front is expected to move into the
region. This will bring in some cooler air to the region. This
should also help clear out some of the smoke.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 247 PM MDT Mon May 13 2024
An upper trough will move across the region on Wednesday,
bringing additional chances for showers and thunderstorms. There
is a possibility that any thunderstorms that develop will
produce heavy rain, which may result in some localized water
issues.
Thursday, the trough will exit the region, and the area will
come under northwest flow on Friday. Expected high temperatures
will be in the 70s Thursday.
Expect a warm up on Friday with the northwest flow in place,
ahead of our next system. High temperatures Friday will be in
the 80s. A few low 90s will be possible for an area along and
east of a line from McCook to Colby to Tribune. Periodic showers
and storms will be possible over the weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 535 PM MDT Mon May 13 2024
Aside from a potential for sub-VFR conditions associated with
scattered showers/storms Tuesday afternoon and evening
(~22-03Z).. VFR conditions are anticipated to prevail through
the TAF period. Guidance suggests a relatively greater potential
for convection at the GLD terminal (compared to MCK), though..
confidence in convective coverage and location is below average.
N to NNE winds at 10-15 knots will weaken and become variable
overnight. Winds will shift to the S and increase to 10-15 knots
late Tuesday morning. At GLD, south winds may weaken and become
variable during the afternoon. At MCK, a southerly breeze may
persist through the afternoon. Gusty/erratic winds can be
expected in vicinity of any showers/storms.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...Wekesser
LONG TERM...Wekesser
AVIATION...Vincent
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
745 PM CDT Mon May 13 2024
.KEY MESSAGES...
- Showers and storms are expected (70-90% chance) through Tuesday
afternoon. Expect generally 0.50 to 1 inch with 10-30% chance
of over 1.5 inches.
- Another system will bring rain to the area Thursday into Friday,
with generally another 0.25 to 0.75 inches of rain.
&&
.UPDATE...
Issued at 745 PM CDT Mon May 13 2024
Majority of the showers/storms are currently northeast of a
Galesburg-Olney line. There was a noticeable uptick in lightning
activity in the 5-6 pm time frame, though this has been waning
some over the last half hour as we get closer to sunset. The focus
the remainder of the evening will continue to shift northward,
north of a weak boundary that is currently extending from near
Rushville to Danville. High-res models show some decrease in
showers over most areas after midnight, before the next surge
begins to lift in toward sunrise.
Evening forecast updates mainly concentrated on rain chances into
Tuesday.
Geelhart
&&
.DISCUSSION...
Issued at 324 PM CDT Mon May 13 2024
The expected upper level low is currently in eastern KS according
the latest analysis...but continues to push eastward towards IL.
We`ve seen some showers and weak thunderstorms across central IL
this afternoon and expect coverage to increase through late
afternoon and into the early evening hours. Deep shear remains
weak at <20 kts with MLCAPE of 500-1000 J/kg. The latest RAP model
has a pocket or two of MLCAPE around 1000 J/kg this afternoon from
4-7 PM when storms will likely be the strongest. A few near-severe
storms will be possible with hail close to 1" and/or wind gusts
nearing 60 mph, but generally, severe storms are unlikely this
afternoon/evening.
Showers and perhaps some thunderstorms will be possible through
the night as a mid level vort lobe rotates northward around the
approaching system. Another lobe rotates north- northwestward
tomorrow morning with the low moving from eastern MO into southern
IL during the day Tuesday. Expect showers and embedded
thunderstorms to continue Tuesday, with the strongest storms south
of I-72. With MUCAPE generally around 500 J/kg up to 1000 J/kg
and deep share around 20-30 kts, severe potential is limited once
again tomorrow. Rainfall will likely be in the 0.5 to 1" range
across much of the area, with a 10-30% chance of over 1.5" for the
Mon-Tue total.
The area sees weak ridging on Wednesday, providing a break from
precipitation. However, rain chances return on Thursday and into
Friday as the next upper wave moves through the region. Not too
excited about severe weather chances with this second system at
this time since the NBM has CAPEs at 500 J/kg or less along with
25 kts of deep shear. However, the latest ECMWF is showing some
higher CAPEs for Friday, so will need to watch how this one
evolves. Generally expecting around 0.5" of rain with this system.
Weak ridging in NW flow aloft is expected for Saturday with an
upper wave passing to the north on Sunday. We`ll see a surge of
warm air ahead of the associated surface low pressure system,
bringing highs into the 80s for the weekend. More shower and
thunderstorm activity is possible by Sunday with the frontal
system and upper support. We`re still too far out to speculate on
severe potential with this one.
Knutsvig
&&
.AVIATION... (For the 00z TAFs through 00z Tuesday Evening)
Issued at 620 PM CDT Mon May 13 2024
Scattered thunderstorms continue across a large part of central
Illinois early this evening, and are expected to continue through
about 02-03Z. Some brief MVFR/IFR visibility drops will accompany
the heavier showers, but a more widespread ceiling lowering is
expected late evening. By 08-09Z, probabilities of ceilings below
1,000 feet are around 60-80%, with any significant improvements
holding off until after midday.
With the storm system slowly advancing across the area Tuesday,
widespread showers will return before midday. Isolated lightning
cannot be ruled out throughout the afternoon, but chances are too
low to include a mention at this point.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1141 PM EDT Mon May 13 2024
.KEY MESSAGES...
- Dry weather holds into the afternoon, before an approaching
system from the Plains brings more unsettled conditions.
- Shower and thunderstorm chances will be around through Wednesday
with a lull on Thursday then renewed chances to close out the
week.
- Near, to a little above, normal temperatures are expected
through the work week.
&&
.UPDATE...
Issued at 1141 PM EDT MON MAY 13 2024
A passing mid-level short wave is kicking off some shower
activity across portions of the forecast area. The more notable
light measurable precipitation has occurred across our southwest,
where lower dew point depressions were in place initially. As the
showers travel east and northeast, relatively drier low level air
has eroded some of this activity, as seen on radar trends. Have
freshened up the PoPs through the night, accounting for this
current uptick, and then allowing for some diminishment behind the
departing wave overnight. This will be followed by yet another
increase towards dawn, as the next short wave approaches,
affecting locations more so in the east. Instability has also been
lacking across the area, and given the meager MU CAPE forecast
for the rest of the night, have removed thunder from the forecast.
Lows will range from the upper 50s southwest, to the lower 60s
northeast. Updates have been sent.
UPDATE Issued at 726 PM EDT MON MAY 13 2024
The NBM, and the current forecast, still depict high-end chance to
categorical PoPs (50 to 90) developing by mid-evening with the
increase in southerly low-level winds after dark. However, given
how dry it looks and given eastern Kentucky lies on the cool side
of the upper-level jet stream, am inclined to think those PoPs are
overdone. If showers do not begin to develop shortly after dark,
will lower PoPs accordingly.
Main change with the early evening update is to lower temperatures
in the south where cloud cover has kept temperatures in the lower
60s late this afternoon into early evening. Otherwise, just
blended in the near-term forecast with current observations.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 337 PM EDT MON MAY 13 2024
The afternoon surface analysis shows high pressure is still out to
the east along the North Carolina coast line. Meanwhile, low
pressure is developing across Missouri along with a cold front.
This is providing south and southeast flow at the surface, which
has led to mostly downslope flow. This has kept it dry this
afternoon and will continue to be the case until we can moisten up
in the low levels later this afternoon and evening. In the mid-
and upper levels an upper low will push toward the Ohio Valley
tonight. The CAMs and ensembles like the HREF have been in decent
agreement with bringing a line of showers and possibly a
thunderstorm across the area later this evening into the overnight
hours. This could be in response to a slight increase in the low
level jet noted in some of the ensembles. Given this opted to stay
closer to the NBM PPI for PoPs this evening and into tonight, as
it seemed to have this handled fairly well.
Tuesday, this upper low meanders eastward toward the Ohio Valley.
This coupled with and area of low pressure and some upper level
divergence will give way to another shot (70-90 percent) of
showers and thunderstorms through the day. However, there will be
a lull in activity early in the day. Some of the data suggests
there would be just enough instability (MUCAPE around 1000-2000
J/kg) and shear (effective shear of 30-40 knots) to help organize
some of this convection. The HRRR and other CAMs want to bring an
line of convection through the area tomorrow afternoon around 17Z
and progresses across the area through the remainder of the
afternoon into the evening. Right now, it looks like a marginal
set up for severe weather, but strong storm or two can`t be
completely ruled out. The primary risk would be small to perhaps
marginally severe hail. SPC did push the marginal risk into a very
small portion of the Cumberland Valley. Tuesday night, the shower
and thunderstorm chances roll on given upper low is still
meandering east. However, its a little more uncertain how
convection will evolve through the evening given the line that is
expected to move through in the afternoon and early evening. For
now will keep highest PoPs in the evening time and lessen some
through the night.
.LONG TERM...(Wednesday through Monday)
Issued at 400 PM EDT MON MAY 13 2024
Still looking at an active weather pattern in the extended, as a
series of low pressure systems are forecast to move across the
eastern half of the CONUS. The models were in pretty agreement with
the overall large scale pattern aloft and systems evolution. The
ECMWF was a bit wetter at times than the GFS, but overall the models
had similar solutions. Used the GFS Ensembles for overall pattern
details and locations and evolution of lows and highs. Precipitation
details were derived from combination of the GFS and ECMWF models.
The pattern will begin with a weak trough of low pressure, both
aloft and at the surface, moving through the Ohio and Tennessee
Valleys Wednesday and Wednesday night, and eventually out to sea off
the southeast CONUS Atlantic coast by Thursday afternoon. In the
meantime, we should see a weak northern stream trough moving quickly
across the Canadian border region and across the Great Lakes to end
the week. Another more pronounced trough aloft is forecast to be
making its way through the southern stream and through the southern
Plains and Gulf to end the week and on into the weekend. These two
troughs are forecast to phase on Friday, and will bring rounds of
rain to eastern Kentucky Friday through Sunday. The initial trough
will bring widespread showers and storms to the area Wednesday and
Wednesday night, with some precip lingering behind the trough as it
departs late Thursday.
Another system will be right on the heels of the first, and will
bring another batch of showers and storms to our area Thursday night
through Saturday, as it slowly moves through the region. The highest
rain chances during the second system passage will be Friday, as a
cold front pushes through. This batch of rain should taper off late
Friday night and Saturday, with a few showers and storms lingering
behind the departed front. The details for the end of the extended
are a bit murkier, due to model uncertainty, but it appears that we
will see scattered showers and storms moving through the area again
Sunday through Monday, perhaps triggered by the passage of either a
northern or southern stream low, or from the phasing of each. Due to
this, precip chances for Sunday through Monday were kept fairly low,
20 to 40 percent to be exact, for now. The best times for showers
and storms will be during the afternoon and evening hours, when peak
heating and instability will be maximized. There will be, however,
enough instability left over to allow for some night time
thunderstorms as well through out the extended period.
Aside from Wednesday, when highs are expected to be slightly below
normal, we should see above average temperatures, both day and
night, through most of the period. Daytime highs will average from
the upper 70s to lower 80s, and night time lows the upper 50s to
lower 60s. Persistent southerly and southwesterly flow will keep a
steady flux of warm, moist air feeding into the area and should help
keep temperatures up in spite of the expected clouds and rain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 808 PM EDT MON MAY 13 2024
Conditions will remain mainly VFR through 06z, besides some
passing light shower activity, that made lead to some temporary
MVFR visibilities. Ceilings will lower to low-end VFR or MVFR
between 06 and 15z, with locations along and west of a line from
KSYM to KLOZ likely seeing the lower heights. Light passing
showers will continue to threaten at times tonight into early
Tuesday morning, but these look to be more scattered in nature.
The better coverage of showers and/or thunderstorms looks to hold
off for most locations until late Tuesday morning and especially
the afternoon, when a more defined upper level disturbance rotates
in from the west. South to southeast winds of 5 to 10 kts will
diminish this evening and overnight, before backing to the south
to south southwest and increasing once again to 5 to 10 kts by mid
to late morning Tuesday.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...DJ
LONG TERM...AR
AVIATION...GEOGERIAN
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
951 PM CDT Mon May 13 2024
...New UPDATE...
.UPDATE...
Issued at 950 PM CDT Mon May 13 2024
Current forecast remains on track.
Thunderstorms continued to develop over the MS River delta of
eastern AR at midevening. These storms were likely becoming
rooted in an elevated layer as they lifted north from Arklamiss.
HRRR sounding for Clarksdale, MS at 03Z depicted a shallow
nocturnal inversion, with nearly 1000 J/kg of mixed layer CAPE
above 800mb. Below this layer, down to the inversion, lapse rates
are depicted as moist adiabatic. For updrafts surviving this
marginally stable low layer, relatively steep midlevel lapse
rates will support marginally severe hail. Increasing deep layer
bulk shear is expected under the right entrance region of a 250mb
speed max. This may aid storm organization and persistence
potential into the early overnight hours.
PWB
&&
.SYNOPSIS...
Issued at 248 PM CDT Mon May 13 2024
Unsettled weather will continue through Tuesday as an upper level
disturbance and cold front slowly progress across the region. A
few strong storms are possible late tonight and again in the
afternoon hours on Tuesday. Dry conditions will return on
Wednesday as we are in between weather systems. Showers and
thunderstorms will return Thursday and persist through early
Saturday. A mostly dry weekend with near normal temperatures is
expected.
&&
.DISCUSSION...
(This evening through next Sunday)
Issued at 248 PM CDT Mon May 13 2024
A cool and cloudy afternoon across the Mid-South. Heavy cloud
cover has persisted this afternoon beneath southwest flow aloft.
The latest KNQA radar sweep reveals just a few light showers,
mainly over portions of northwest Tennessee. The latest GOES east
Water Vapor Imagery shows a robust MCS across the Florida
Panhandle, with another MCS over southeast Texas. A compact upper
low was also analyzed near the Missouri and Kansas border.
Mainly dry conditions will persist through early evening across
the entire Mid-South. Thereafter, a shortwave will eject from the
base of upper low and nearly phase with a southern stream wave
coming out of the ArkLaTex. As it does, two areas of scattered
showers and thunderstorms will develop this evening. A few of the
storms could be strong to severe, as up to 1000 J/kg of MLCAPE and
up to 50 knots of deep layer shear will be on hand. The main
threats with any strong storms will be hail and gusty winds, as
mid level lapse rates will approach 7.5 C/km and DCAPE values
will be nearing 800 J/kg. The threat of strong storms should end
as storms approach the Tennessee River before sunrise Tuesday
morning.
The upper low and associated surface low will push slowly through
the Mid-South late tomorrow morning through tomorrow evening.
Instability will be maximized ahead of the front or for areas east
of the Mississippi River, where up to 1500 J/kg of MLCAPE will be
available. Strong storms could form along the cold front by early
afternoon and produce hail and gusty winds. Storms will likely
push east of the Tennessee River before midnight.
Dry conditions will return on Wednesday and persist into much of
Thursday as shortwave ridging builds in overhead. The weather will
become unsettled once again late Thursday, as several shortwaves
translate through southwest flow aloft. A marginal threat of
strong storms will likely exist during this period as 1000 J/kg of
SBCAPE will be available and up to 30 knots of shear.
Mainly dry conditions are expected this weekend as we remain under
a weak ridge. Did carry a 20 to 30 PoP each day, as some diurnal
showers and thunderstorms may bubble up. A weak and mostly dry cold
front looks to move through the Lower Mississippi Valley late
Sunday into Monday as a large trough digs across the Ohio Valley.
AC3
&&
.AVIATION...
(00Z TAFS)
Issued at 627 PM CDT Mon May 13 2024
A couple of shortwave troughs rotating around an upper-level low
centered near west central Missouri will be the focus for showers
and elevated TS later this evening and overnight. This is
generally in line with the latest high-res, TCF, and GLAMP
guidance. Ceilings were adjusted for the start of the 00Z TAF
period as latest guidance including HREF Grand Ensemble data holds
off IFR ceilings until mostly during the overnight period. An
improvement to MVFR conditions anticipated Tuesday morning, then
VFR conditions by Tuesday afternoon.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...AC3
AVIATION...CJC
Area Forecast Discussion
National Weather Service Morristown TN
1125 PM EDT Mon May 13 2024
...New UPDATE...
.UPDATE...
Issued at 1119 PM EDT Mon May 13 2024
Forecast is on track tonight, with no significant changes made to
the current forecast. Looking ahead to tomorrow, the overall
expectation is the same. Couple rounds of showers and
thunderstorms expected, with the stronger thunderstorms bordering
severe arriving in the late afternoon in a broken set of clusters
of cells. Stronger to severe activity will most likely be south
of Interstate 40.
&&
.SHORT TERM...
(This evening through Tuesday)
Issued at 215 PM EDT Mon May 13 2024
Key Messages:
1. Wind Advisory for the far east Tennessee Mountains and
Foothills. Gust up to 45 mph possible.
2. Strong to possibly severe storms late Tuesday afternoon and
evening for the Plateau and southeast Tennessee. Marginal severe
hail up to 1 inch and strong gusty winds to 50 mph are possible.
Low-end threat of tornadoes across southeast Tennessee late in the
day.
Discussion:
Through the rest of the afternoon into the evening, weak
isentropic lift will produce scattered showers with light rain or
sprinkles. Besides the potential of light rain, main concern will
be windy conditions across the far east Tennessee Mountains and
Foothills. Camp Creek currently reporting gusts to around 35 mph
but speeds have decreased at Cove Mountains. The low-level jet is
forecast by HREF to increase this evening and expect the greatest
potential of strong winds between 01-06Z.
The boundary layer jet will enhance the potential for scattered
showers this evening/early morning especially over southwest
Virginia and northeast Tennessee.
For Tuesday, upper forcing from the left exit region of the jet
moving into the northern Gulf Coast states and continued
isentropic lift will pull warm/moist air into the region. The
model soundings show more elevated instability as the warm front
remains south of the area until late. Exact timing of a band of
scattered showers and storms remains uncertain but do expect an
area of convection during the day moving northeast.
By late afternoon, another area of convection will form over
middle Tennessee moving the Plateau and southeast Tennessee. This
second area of showers and storms will be more surface based with
MLCAPES up to 1500-1800. Shear will be strong enough to support
organized multi-cluster storms with effective shear of 35 m2/s2.
Mid-level lapse rates are near 6.5 which also supports decent hail
growth resident time. Overall, marginal severe hail and damaging
winds are the main threat.
The HREF is showing some 2-5km updraft helicity tracks across
southeast Tennessee with latest HRRR depicting 0-1km shear of
15-20kts. There is a low-end probability of tornado development
across these areas late in the day.
&&
.LONG TERM...
(Tuesday night through next Monday)
Issued at 215 PM EDT Mon May 13 2024
Key Messages:
1. Showers and thunderstorms continue through Wednesday.
2. A short break is expected, before another round of storms begins
heading into the weekend.
Discussion:
Tuesday evening/night should be the time-frame when we see the
boundary associated with this early week system move thorugh the
area providing a decent environment for thunderstorms. Forecast
soundings show there could be areas of over 500 J/kg of available
CAPE and some moderate (albeit mostly unidirectional) shear in the
mid and deep layers. This atmosphere should be conducive to seeing
more widespread thunderstorms and maybe even some strong to severe
thunderstorms. In the strongest storms we could possibly see near
severe level winds and marginally severe hail... But the primary
threat for the day continues to be the chances for isolated flooding
under heavy thunderstorms. With the weak and nearly unidirectional
shear the threat for tornadoes looks very low at this time. We
should get a break for much of the night and into early Wednesday
morning before the base of the trough/low moves overhead later in
the day leading to another (but hopefully more tame) round of
showers and thunderstorms.
Much of Wednesday night and Thursday should be dry as we sit between
systems and we should see temperatures climb back up to near or
above normal as we head towards the weekend.
By Friday we`ll see increasing precipitation chances as another
system looks to move out of the southern plains towards the
Ohio/Tennessee Valleys through the weekend. There is high confidence
in showers and thunderstorms across the southeast Friday/Saturday,
but lower confidence on the timing and strength of the storms. Some
models are showing more vigorous thunderstorm activity to our south
near the Gulf Coast which typically inhibits convection in the
southern Appalachian. But if the boundary and storms develop further
to the north we`ll likely see more widespread thunderstorms in our
region.
&&
.AVIATION...
(00Z TAFS)
Issued at 736 PM EDT Mon May 13 2024
Expecting CIGs to deteriorate to IFR at CHA tonight, with a return
to VFR by the late afternoon. Given a minor wind event in the
mountains, TYS and TRI should be more resistant to low ceilings.
Two rounds of rain are probable tomorrow, first crossing from SW
to NE in the late morning to early afternoon, second a set of
afternoon TS in the late afternoon to the end of the period. Any
TS will potentially have brief reductions in VIS and gusty winds.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 63 76 63 78 / 50 90 70 60
Knoxville McGhee Tyson Airport, TN 60 76 61 74 / 50 80 90 90
Oak Ridge, TN 60 75 61 74 / 40 80 90 90
Tri Cities Airport, TN 58 76 58 71 / 60 60 80 100
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Wind Advisory until 4 AM EDT Tuesday for Blount Smoky Mountains-
Cocke Smoky Mountains-Sevier Smoky Mountains-Southeast
Carter-Southeast Greene-Southeast Monroe-Unicoi.
VA...NONE.
&&
$$
SHORT TERM...Wellington
AVIATION...Wellington
Area Forecast Discussion
National Weather Service Paducah KY
142 PM CDT Mon May 13 2024
.KEY MESSAGES...
- Shower and thunderstorm chances will peak later tonight into
Tuesday. A stronger storm cannot be ruled out, but the risk
remains very marginal.
- While rain chances on Wednesday will be much lower, another
risk for showers and thunderstorms returns Thursday afternoon
into Friday. Rain chances may linger through Sunday, but the
weekend overall does not appear to be a washout.
- Temperatures will be near normal through the middle of the
week before gradually rising above normal late week into the
weekend.
&&
.DISCUSSION...
Issued at 140 PM CDT Mon May 13 2024
The synoptic setup this week is quite unsettled as a 500 mb
shortwave trough and low ejects across the Plains today, providing
forcing for ascent. Scattered showers and a few isolated
thunderstorms will be possible through this evening, with the better
risk for convection arriving late tonight into early Tuesday
morning. The RAP shows about 600-850 J/kg of 0-1km MLCAPE with
pockets of bulk shear upwards 30-35 kts and 700-500 mb lapse rates
around 6.5 C/km, keeping the severe risk very marginal mainly across
southeast Missouri. Although the 0-1km MLCAPE will be upwards of
1000-1500 J/kg Tuesday afternoon when another uptick in pcpn is
progged, the shear will be decreasing. Overall, the setup is very
marginal, but a stronger storm cannot be ruled out, with the risk
shifting east into western Kentucky on Tuesday. QPF generally
remains between a half to one inch for most of the FA, with locally
higher amounts possible.
By Wednesday, the FA will still be under the influence of cyclonic
flow on the backside of the aformentioned 500 mb low as recent runs
of the GEFS/EPS and deterministic ECMWF are more pessimistic.
Meanwhile, the 12z GFS/NAM remain more progressive keeping most of
the FA dry. Given that the overall trend favors a slower departure,
NBMs 20-40% PoPs seem reasonable for Wednesday, especially across
southwest Indiana and western Kentucky where the risk of seeing pcpn
will be the greatest. Locations near and west of the Mississippi not
only likely remain dry, but can also expect breaks of sun as a weak
ridge axis aloft eventually moves over the entire FA Wednesday night.
While Thursday looks to start off dry, southern stream energy will
eventually eject NE towards the FA bringing the risk for more
showers and thunderstorms Thursday afternoon into Friday.
Uncertainty then increases over the weekend as model ensembles are
not in agreement on if the southern stream energy gets held back
with NBM chance PoPs progged for both days. Despite the lower
forecast confidence, the entire weekend does not appear to be a
washout. It is also possible most of the weekend remains dry if the
12z ECMWF/CMC were to be correct while the GFS lingers pcpn into
Saturday.
Temperatures will be near normal Tuesday and Wednesday with maxTs in
the mid to upper 70s and minTs in the upper 50s to lower 60s.
Daytime temps gradually warmer into the low 80s Thursday and Friday
before eventually rising into the mid 80s over the weekend with
nighttime temps in the low to mid 60s.
&&
.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1213 PM CDT Mon May 13 2024
The main concern is MVFR/IFR cigs building in from the west
through this evening as a disturbance approaches. A few
scattered showers will also be possible, perhaps a rumble of
thunder. A greater risk for showers and storms arrive during the
overnight when TSRA cannot be ruled out, especially at
KCGI/KPAH. Brief MVFR vsbys are also possible early Tuesday
morning as low cigs prevail across the entire region. Light S-SE
winds between 5-11 kts are expected.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
DISCUSSION...DW
AVIATION...DW
Area Forecast Discussion
National Weather Service Salt Lake City UT
353 PM MDT Mon May 13 2024
.SYNOPSIS...A weak storm system will graze northern Utah through
this evening before another system moves through the area Tuesday
into Wednesday, bringing less warm and more unsettled conditions.
High pressure will return late in the week with a renewed warming
and drying trend.
&&
.SHORT TERM (Through 12Z/6AM Wednesday)...Early Monday afternoon,
a shortwave trough was rotating eastward through southwest Idaho.
Increased moisture, lift and kinematics associated with this
feature will move across northern Utah and SW Wyoming this
evening. The combination of 500-750J/kg of SBCAPE (per HREF
ensemble mean), deep-layer shear in the 25-30kt range, just
enough moisture (PWATs in the 0.5" to 0.6" range) and ascent from
the shortwave will be enough to encourage isolated to scattered
showers and storms, with a few stronger storms across northern
Utah and SW Wyoming through this evening. Main hazards will be
gusty microburst/outflow winds, lightning and sub-severe hail up
to 3/4" of an inch. Latest HREF wind probabilities peg a 70%
contour for gusts up to 39 mph across northern Utah, with a 10%
probability contour for gusts up to 58 mph centered over extreme
NW Utah. There is a region of higher wind probabilities over the
Dugway area as well, a region that is no stranger to
convectively-induced wind gusts. Farther south, isolated showers
are attempting to initiate over high terrain areas of southern
Utah, but with much lower lift, instability and shear here,
activity will tend to diminish as it moves off the terrain. Thanks
to the large-scale ascent courtesy of the shortwave, additional
shower and thunderstorm development will persist through the
evening across northern Utah and SW Wyoming, with activity
winding down quickly after midnight.
A weak cold front associated with this lead shortwave will stall
over central Utah tonight. A trailing shortwave will pivot across
eastern Idaho and northeastern Utah by Tuesday afternoon,
reinvigorating shower and thunderstorm activity. While convective
initiation can`t be ruled out across terrain features across the
area, initiation will tend to be tied to the near stationary
frontal boundary across central Utah. Moisture, lift, instability
and shear parameters look similar for tomorrow when compared to
day, with the most robust ingredients centered over central Utah.
Gusty outflow winds and sub-severe hail will be the main threats.
With weak westerly flow parallel to the nearly stationary frontal
boundary, there as a low-end risk for flash flooding should any
stronger cells tend to train across vulnerable locations. 1-hr
ensemble max QPF values do reach into the 0.50"-1.00" range,
suggestive that cells that verify on the high end of the
distribution could indeed present a low-end flash flood risk.
Finally, the HRRR smoke does indicate a low concentration of
near-surface smoke that is shown advecting across the area in the
post-frontal airmass across northern and central Utah on Tuesday.
This smoke appears to be originating from a wildfire in Oregon.
Check Utah DEQ for air quality forecasts.
.LONG TERM (After 12Z/6AM Wednesday)...Long term forecast period
begins within cooler deep north to northwesterly flow as a weak
grazing shortwave departs eastward. Some semblance of an associated
diffuse frontal boundary may remain draped across the south and
eastern portions of Utah, but expect this feature to largely be
washed out and only serve as maybe a very slight enhancement to
lower level convergence. In general, area will remain unsettled
enough to see some isolated to scattered afternoon convection fire
off of Utah`s high terrain (as well as likely SW Wyoming) and
subsequently gradually drift south to southeastward downwind.
Subcloud layers will be fairly dry, so could see some moderate
downburst winds from any convection that matures sufficiently.
Additionally, given fairly weak storm motion, could at least see
some potential for convection to drift over more sensitive and fast
responding drainages/washes, and will need to keep an eye on flood
threat accordingly. That said, given dry subcloud layers (though
PWATs near normal) and limited coverage, thinking the threat overall
is on the lower end. Aside from the precipitation potential, weak
post frontal environment will result in slightly cooler afternoon
temperatures than the prior day, though still near to slightly above
normal. Additionally, HRRR Near-Surface Smoke Density product
suggests maybe some lingering light smoke/haze associated with the
ongoing Little Yamsay fire in Oregon, though that will also be
dependent on ongoing containment efforts.
Guidance for Thursday still shows good agreement in ridging nosing
in from the west, with continued ridging into Friday now also
supported by the majority of deterministic and ensemble sources. In
addition to increased dry and stable conditions, this ridge will
help initiate a warmup, with forecast highs along the Wasatch Front
by Friday in the low to mid 80s, and for Lower Washington County in
the mid 90s. While highly unlikely, NBM probabilities do show a 4%
chance of KSLC hitting 90F for the first time this year. For those
not ready to hear it, the good news at least is that the average
first date of 90F or higher for KSLC is not until June 8th, so we
probably have a little more time to enjoy Spring.
Unfortunately, suite of ensemble guidance continues to diverge on
the pattern evolution moving into the weekend, primarily in regard
to the position/strength of the ridge as a modestly strong mid/upper
jet and impulse approaches through the PacNW. An additional muddying
factor is a more southern stream cutoff low approaching the
mid/lower California coast, and if/how/when this may interact with
the northern stream. A stronger ridge solution would yield continued
warm/dry conditions, where a trough would bring about cooler and
more unsettled conditions depending on the strength. For Saturday,
ensembles sit with roughly 55% of members supporting continued
ridging, and 45% supporting at least some sort of weak troughing.
Sunday stands closer to a 50%/50% split between trough/ridge, with
20% of overall solutions showing some phasing between southern
cutoff and northern trough, which would be the coolest/wettest of
plausible solutions. Monday offers little in the way of extra
confidence. Opted to keep NBM values with this forecast package,
which include isolated to scattered showers/thunderstorms and
seasonably mild conditions, but worth mentioning the spread between
25th/75th percentile for highs remains around 10F or so. Overall,
will likely see exact numbers for temps/PoPs fluctuate a decent bit
until guidance hopefully begins to trend towards a solution.
&&
.AVIATION...KSLC...Showers and thunderstorms, mainly to the
northwest, will diminish by around 06Z. Sprinkles or light rain
showers are likely, but outflow winds from 00-03Z could enhance
prevailing northwest winds. Clouds will diminish as showers and
thunderstorms taper off. Winds will transition to southeast around
06Z.
.REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers and
thunderstorms for southwest Wyoming and northern Utah will diminish
by around 06Z. Gusty, erratic outflow winds are likely near showers
and thunderstorms. Those will diminish from 03-06Z. Showers will be
isolated further south with less outflow wind compared to the north.
Showers will diminish through the evening.
&&
.FIRE WEATHER...A weak cold front will move through northern Utah
this evening, bringing isolated showers and thunderstorms. The
weak cold front will move southward across central Utah on
Tuesday, and finally to southern Utah by Wednesday. Isolated
to scattered showers and storms will accompany the front each day,
favoring central and southern Utah by Tuesday and Wednesday.
Isolated areas will see wetting rains, but most areas are not
expected to see wetting rains with this activity. Warmer, drier
conditions will build across the state for Thursday and Friday,
with increasingly poor overnight recovery across southern Utah,
especially for lower elevation areas. Another weak system is
forecast to graze northern Utah this weekend, bringing some gusty
westerly winds, especially as one approaches the Idaho border.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&
$$
ADeSmet/Warthen/Wilson
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