Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/16/24
Area Forecast Discussion
National Weather Service La Crosse WI
1058 PM CDT Wed May 15 2024
.KEY MESSAGES...
- Showers move through overnight with additional thunderstorms
possibly developing east of the Mississippi River Thursday
afternoon. Can`t rule out hail with storms tomorrow
afternoon.
- Seasonably warm temperatures in the 70s to low 80s through the
weekend.
- Next rounds of showers and storms come Saturday, more active
period for showers and storms shaping up for the first part of
next week (predictability low at the present time).
&&
.DISCUSSION...
Issued at 240 PM CDT Wed May 15 2024
Tonight and Thursday: Multiple Rounds of Showers and Storms
A predominantly zonal flow exists this afternoon across the
CONUS with a few waves of note across the country. One such wave
axis was evident across the western Dakotas in water vapor
imagery with a weak surface low reflection over the northern
Siouxland region driving a broad swath of showers and isolated
thunderstorms. This complex slides eastward tonight, with the
short-range guidance struggling to resolve how the precipitation
shield will evolve during this time owing to a lack of both
instability and favorable wind profiles. Overall impacts tonight
will be minimal outside of some heavier showers and occasional
lightning.
The convective complex works ahead of the surface front by the
morning hours, and depending on how much recovery takes place
in its wake, we may see redevelopment along the surface trough
in the early afternoon on Thursday east of the Mississippi
River. A 70-kt upper level jet overspreads the region as it
rounds the base of the upper trough, lengthening hodographs
ahead of the frontal boundary. The biggest question revolves
around how much recovery can take place ahead of the front
before it clears the region. The 12/18Z HRRR runs show about
1000-1400 J/kg of SBCAPE developing ahead of the trough, but it
remains to see if this scenario will pan out. If storms do
manage to form, hail of 1-2" in diameter would be the main
threat. Explicit composite reflectivity progs from members of
the 12Z HREF do lend credence to a line of convection developing
by 18-20Z and exiting the area by 22-23Z, but a small change in
the thermodynamic environment could quickly change this
scenario. Linear hodographs would support storm splitters and
mergers, so the line would grow upscale quickly as it advances
eastward into south-central WI during the mid to late afternoon
and morph into more of a wind threat.
Saturday and Early Next Week: Next Rounds of Rainfall
Split flow brings dry conditions for Friday, with the
progressive flow ushering the next negatively-tilted shortwave
through during the afternoon and evening on Saturday. With the
shortwave already recoiling to the north and taking the 100-kt
300-mb jet with it, there is some uncertainty as to how much
development takes place along the attendant surface front that
slides into our area. Forecast soundings from the GEFS members
don`t show much for inhibition ahead of this front (albeit with
lower CAPE values), so it is probable that we`ll see some
scattered storms with this surface forcing. Overall impacts
will be limited in space and time owing to the lack of deep
shear and compact hodographs.
Attention then turns to early next week as longwave troughing
deepens over the western CONUS, ejecting multiple weak
perturbations through the region between Sunday and Tuesday.
The subtle nature of these waves makes them tough to pin down
more than a few days out. Looking though the 12Z guidance, odds
are better that the surface baroclinic zone will stay south of
the region and take the severe weather threat with it. That
being said, there is plenty of variability in the ensemble
members and such factors will be increasingly driven by how the
previous day`s convection unfolds. This longwave ejects Tuesday
and may be enough to lift the warm sector into the region, but
confidence in such a scenario is low at the present time.
Temperature Trends into Next Week
Overall, expect at or slightly above average temperatures for
the remainder of the week and into next week with highs in the
70s to low 80s and lows in the 40s and 50s. Despite the passage
of a weak cold front Thursday night, warm 925-700-mb southwesterly
flow builds in its wake across the High Plains for Friday and
Saturday. Some of this warmer lower tropospheric air spills
eastward into the Driftless region and allows highs to creep
into the low 80s during this period. Confidence in the
temperature forecast wanes slowly as we head through the first
half of next week owing to the aforementioned precipitation
uncertainties, but the pattern definitely favors at or above
average temperatures with no cold snaps on the horizon.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1058 PM CDT Wed May 15 2024
A mix of VFR and MVFR conditions are expected through the TAF period
as showers and isolated storms (~15% chance) progress through the
region overnight and into the early morning Thursday. As this
disturbance, passes through the region cigs will begin to drop to
MVFR with visbys of 4-5SM possible in more robust showers. There is
some signal (20-30% chance) for IFR cigs to get into KRST into the
morning hours however this appears unlikely at this time. Otherwise,
as the disturbance begins to exit the region conditions will return
to VFR by the afternoon with diurnal mixing. Depending on how fast
sky cover clears, will have to watch for some redeveloping showers
and storms (Roughly 20% chance at KLSE) east of the Mississippi
River later into the afternoon. Winds will remain fairly light at 5-
10 kts through the TAF period and will shift from the southeast to
west/northwest during the day on Thursday.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Skow
AVIATION...Naylor
Area Forecast Discussion
National Weather Service Corpus Christi TX
553 PM CDT Wed May 15 2024
...New AVIATION...
.SHORT TERM...
(Tonight through Thursday night)
Issued at 339 PM CDT Wed May 15 2024
Key Messages:
Marginal (level 1 of 5) risk of severe thunderstorm tonight and
tomorrow
Medium to high chance of moderate to major risk of heat-related
impacts tomorrow
A warm and sunny afternoon will continue before cloud cover and rain
chances increase this evening into tonight. A few hi-res models led
by the HRRR are showing convection developing this evening over
Mexico and crossing the border into the Rio Grande Plains this
evening after sunset. While chances are low that this activity will
make past the Brush Country, included a 20% chance of precipitation
tonight across the Coastal Plains into the Coastal Bend. As these
storms cross the border, there is a low chance that these storms
could become strong to severe, thus prompting SPC to highlight the
Rio Grande Plains and Brush Country under a Marginal Risk of severe
weather. A shortwave will sweep across the Southern Plains tomorrow
ejecting a weak cold front into Texas. Nevertheless, storms are
expected to develop along the front as it moves southward with
models showing an MCS moving into our CWA and impacting the
Victoria Crossroads, where SPC has a Marginal Risk for severe
weather for tomorrow afternoon. While storms develop north of of
the CWA and move southward, there is also a low chance for showers
and thunderstorms to develop ahead of the front across the
Coastal Plains and Coastal Bend.
Daytime highs tomorrow are going to be highly dependent of the
development of precipitation and cloud cover. If cloud cover is less
than expected, then warmer temperatures can be felt, while if cloud
cover is more then highs will be lower. Along with the warm
temperatures expected tomorrow, dew points in the upper 70s to lower
80s will lead to miserable heat indices tomorrow across the southern
Coastal Plains, southern Coastal Bend and the Brush Country with a
moderate to major risk of heat-related impacts. Overnight lows will
remain mild with only a slight cool down into the mid to upper
70s.
&&
.LONG TERM...
(Friday through next Tuesday)
Issued at 339 PM CDT Wed May 15 2024
Key Messages:
- Marginal Risk (level 1 out of 5) of Severe Storms Friday across the
Victoria Crossroads and northern Coastal Bend.
- A moderate to major risk of heat related impacts Monday through
Wednesday across the Rio Grande Plains and Brush Country.
Models are in good agreement with a long wave trough tracking
eastward across western portions of Texas on Friday and pushing a
dryline/surface trough into S TX. The surface trough will provide
strong low level convergence across the area. CAPE is forecast to be
up to 4400J/kg across the Coastal Bend along with deepening moisture
with PWATs of 1.8 to 2 inches across the northern Coastal Bend. The
upper level energy ahead of the upper trough will increase through
Friday as a 105-110 knot upper level jet nudges across the area and
increases the upper level diffluence across S TX. The combination of
these features will be conducive for strong, possibly severe storms
on Friday. Therefore, the Storms Prediction Center has a marginal
risk of severe weather on Friday across the northern Coastal Bend
and Victoria Crossroads.
The uncertainty is how strong the cap will be and how long it will
take to weaken across the northeastern CWA. Across the south and
west portions of the CWA, it is expected to be drier and more
capped, thus a much lower chance of severe storms across those areas.
Overall, the chance of any storms developing Friday is low to medium
(20-30%), mainly eastern CWA.
Behind the trough, a ridge will build across TX leading to drier
conditions and increasingly hot temperatures. In the low levels, the
humidity is progged to increase early next week leading to Heat
Index values approaching 110 degrees across the Rio Grande Plains
and western Brush Country by Monday and continuing through the
middle of next week. This could lead to a moderate to major risk of
heat related impacts across the Rio Grande Plains and Brush Country.
Heat Advisories may be needed across the western CWA Mon-Wed.
&&
.AVIATION...
(00Z TAFS)
Issued at 548 PM CDT Wed May 15 2024
VFR conditions will persist through this evening. MVFR ceilings
will develop late tonight across South Texas. Brief IFR visibility
is also expected over the Coastal Plains and Victoria Crossroads,
so have left in the TEMPO for ALI and VCT. MVFR ceilings will lift
to VFR by midday Thursday. Isolated to scattered showers and
thunderstorms are possible Thursday.
&&
.MARINE...
Issued at 339 PM CDT Wed May 15 2024
Moderate onshore flow tonight around 15-17 knots will increase to
moderate to strong levels tomorrow between 17-19 knots before
decreasing back to weaker levels under 15 knots tomorrow night.
There is a low to medium chance for showers and thunderstorms across
the local waters tomorrow with the best chances across the northern
bays and offshore waters. If a storm does develop, there is a low
chance they can become strong enough to produce gusts to 34-40
knots. A low chance (10-20%) of showers and thunderstorms are
expected Friday. Weak to moderate onshore flow will continue
through the weekend, with periods of more moderate flow expected
early next week across the southern bays and nearshore waters.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 78 92 78 92 / 20 30 0 20
Victoria 72 89 73 87 / 10 60 20 20
Laredo 78 102 77 98 / 20 0 10 20
Alice 76 94 75 94 / 20 30 10 30
Rockport 78 87 78 88 / 10 30 10 20
Cotulla 77 97 74 96 / 20 20 10 10
Kingsville 78 93 77 92 / 20 20 10 30
Navy Corpus 80 89 80 90 / 10 20 10 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM...JCP
LONG TERM....TE
AVIATION...LS/77
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1155 PM EDT Wed May 15 2024
.KEY MESSAGES...
- Dry conditions into tomorrow.
- Increasing precipitation chances Thursday night with scattered to
numerous showers and possible embedded thunderstorms Friday.
- Low chances for showers and thunderstorms over the weekend, mainly
Saturday, with an active weather pattern setting up early to middle
of next week.
&&
.AVIATION...
Some degree of low level moisture will work back west into the area
around high pressure to the north overnight into early Thursday as
mid/upper level moisture begins to stream in from the west. Will
maintain a very conservative cloud forecast given late evening
trends, but still may be some patches of lower VFR stratus early in
the morning. Meanwhile, cigs between 8-15kft will thicken from the
west as low pressure shifts from the upper midwest to northern Great
Lakes. Any shower activity associated with this moisture feed will
hold off until after 03z-06z. Light northeast flow will veer to
southeast on Thursday.
For DTW/D21 Convection...There is a chance of isolated thunderstorms
within a broader area of scattered showers overnight Thursday night.
While a heavy downpour is not out of the question with some of this
activity, strong storms are not anticipated and impacts should be
minimal.
DTW THRESHOLD PROBABILITIES...
* Low for ceiling aob 5000 feet early Thursday morning (~09z-12z).
* Low for thunderstorms after 06z Thursday night.
&&
.PREV DISCUSSION...
Issued at 350 PM EDT Wed May 15 2024
DISCUSSION...
A surface low pressure will continue the slow progression eastward
today with northeast winds gusting to around 15 knots across most of
southeast Michigan this afternoon. Drier air filtering into the
region has brought decreasing clouds north of I-96 with lingering
clouds to the south with even a hint of elevated smoke from
wildfires present across parts of central Michigan. Any low chance
of precipitation this afternoon has come to an end with dry
conditions expected to hold through this evening and overnight.
Surface high pressure center over Hudson Bay and shortwave ridging
aloft passing through Michigan early in the day will help maintain
dry conditions through much of the day tomorrow, but high falls will
be encroaching into the western/central Great Lakes associated with
an upper Midwest trough. Increasing clouds will arrive downstream of
this feature during the afternoon into the evening. Lower level
moisture advection will ramp up throughout the day as well. Marginal
instability tries to develop along the southwestern fringes of the
CWA during the afternoon, but synoptic lift is rather weak. This
should keep any isolated or scattered showers and possible
thunderstorms that may develop during the afternoon to the west of
the forecast area. Warm advection throughout tomorrow will bring
afternoon high temperatures up a few degrees compared to today into
the mid 70s. Weak shortwave energy over Michigan tomorrow night will
bring increasing precipitation chances during the overnight period,
but any activity should be scattered.
The weakening trough lifting into the northern Great Lakes/Ontario
will drag a weakening frontal boundary through the central Great
Lakes on Friday with more appreciable chances for rainfall during
the morning and afternoon. Models have some increasing instability
into the afternoon ahead of this front. MLCAPE values generally
around 500-750 J/kg are forecast by the RAP for Friday afternoon.
Bulk shear at 0-6 km will be around the 25-40 knot range. Though,
steep mid level lapse rates will be lacking based on the forecast
right now. This environment will be supportive of mainly general
thunderstorms given the lack of strong forcing.
The start of the weekend will see a southern stream shortwave lift
out of the southern plains and into the central/northern Appalachian
Mountains while the northern stream jet situates west to east from
the PacNW through the upper Midwest. Saturday will see weak surface
flow with a relatively warm and moist airmass residing across
Michigan. Weak lift in the vicinity of the southern stream trough
combining with the diurnal instability may be enough to generate
some isolated to possibly scattered convection, though much of the
area probably remains dry. Will maintain lower end PoPs of 20-30%
for Saturday afternoon. Lead shortwave trough at the front end of
the northern stream jet will help drive a cold front through
Michigan on Sunday. Confidence decreases in regards to precipitation
chances along this front, but it looks like chances will be limited
as deeper forcing holds off to the north. Zonal flow pattern sets up
for early next week setting up a possible active stretch of weather.
MARINE...
Low pressure exits the Ohio Valley today, keeping fresh northeast
flow in place. Small Craft Advisories are in effect for Saginaw Bay
through 8pm and for the nearshore zones between Port Sanilac and
Port Huron through 11pm tonight. Northeast wind over the bay up to
25 knots will continue to die down through the evening hours, and
peak hazard conditions have already occurred for that area. High
waves are the concern for the Port Sanilac to Port Huron near shore
zone. High pressure briefly influences the area Thursday morning,
before showers return on Thursday evening into Friday due to low
pressure dragging a front across the Great Lakes. Thunderstorms are
also possible with this event, but other than localized impacts due
to these showers/storms, winds are expected to remain gentle at 10
knots, with waves expected to remain low through Friday and into the
weekend.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
AVIATION.....DG
DISCUSSION...AA
MARINE.......BC
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
537 PM MDT Wed May 15 2024
...New AVIATION...
.SYNOPSIS...
Issued at 155 PM MDT Wed May 15 2024
Much of the area will have a chance for a shower or thunderstorm
for Thursday, but any precipitation will be light. Gusty winds and
small hail will be the main concerns. Starting Friday, we enter a
warming trend, peaking on Sunday. Winds will increase as well
Sunday going forward making for very warm to hot and breezy
afternoons.
&&
.DISCUSSION...
Issued at 155 PM MDT Wed May 15 2024
The weather pattern for our area features a closed low over the
Northern Baja Peninsula and an UL ridge across the Plains, to our
east. Some diffluence is noted on the GFS 500 mb analysis and is
marked by a cumulus field that extends across the Gila and
Sacramento Mountains into Albuquerque`s CWA. Radars are showing
some echos beneath these cumulus clouds. Low rain chances will
continue across these areas through sunset. Much of this activity
will then dissipate, but the HRRR is showing a few showers
lingering throughout the night into the morning, likely associated
with increasing divergence aloft as the low approaches. The low
will shift northeastward, crossing Central NM throughout the day
Thursday, keeping much of the CWA within favorable dynamics and
thermodynamics for instability showers and thunderstorms. The best
chance for activity will be roughly I-10 to the north and
especially the mountains. Looking at forecasting soundings and
severe weather parameters, there won`t be much CAPE, generally
less than 500 J/kg nor much shear, less than 20 knots.
Nevertheless, T-Td spreads 20-40 degrees with high bases and
DCAPE values around 1000 J/kg mean gusty winds up to 50 MPH will
be the primary concern, but I would not be surprised by a severe
caliber gust (58+ MPH) or two either. Given much of the CAPE is
within the ice-growing zone some small hail or graupel (<0.5")
will be possible as well.
Some lingering energy will stick around through Friday morning, so
rain/storm chances do not entirely end until then. We will see the
low/trough be replaced with a building ridge that will translate
eastward. Temperatures will warm each afternoon Friday through
Sunday. By Sunday afternoon, the ridge axis will be to our east
with deep SW-flow, allowing us to approach our first 100 degree
day at El Paso. Yesterday, both the GFS and Euro showed a trough
passing NM on Monday, but both models have slowed its passage.
The GFS is about 6-12 hours slower pushing the trough through
Monday night. Winds will would be breezy in this situation with
fire danger being the concern. The Euro is considerably slower,
pushing the trough through Tuesday morning, meaning Monday and
Tuesday would both be breezy but with marginal fire concerns. In
either case it will be dry and warm to very warm to hot.
&&
.AVIATION...
(00Z TAFS)
Issued at 525 PM MDT Wed May 15 2024
Breezy winds expected for much of the period, mostly from W-SW.
Winds remain AOA 10kts through the AM, becoming gusty during the
day tomorrow to around 25kts. An upper disturbance moves in from
the north during the period, increasing the threat of TSRA for all
TAF sites. KTCS is most likely to see lightning nearby tomorrow
afternoon with the activity drifting southward late in the period.
A few SHRA also should develop along the Black Range near KTCS
early in the AM. No mention of TSRA in the southern three
terminals since confidence is not high enough. To signify the
elevated storm threat, SCT-BKN100 have been added later in the
period. Gusty and erratic outflow winds are possible with this
activity.
&&
.FIRE WEATHER...
Issued at 155 PM MDT Wed May 15 2024
An upper-level system will move through the area throughout the
day on Thursday. It will bring an increase in moisture as well as
a bit cooler temperatures, especially across the northern half of
the forecast area and for the mountains. It will also bring at
least scattered showers and a few thunderstorms, especially for
the mountains. Min RH values will still be on the low side, so dry
lightning and gusty winds are the main concerns with any stronger
cell. Small hail may also occur. This system clears out Friday,
and we enter a warm and dry pattern. Winds will begin to increase
for Sunday allowing elevated conditions. On Monday, winds
increase further with widespread near critical to critical
conditions expected. The magnitude of winds is a bit uncertain,
but confidence is high for very dry air.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 65 86 62 91 / 10 20 10 0
Sierra Blanca 62 80 54 84 / 10 10 0 10
Las Cruces 59 83 56 90 / 10 40 10 10
Alamogordo 55 78 52 86 / 10 60 10 10
Cloudcroft 40 55 39 63 / 10 80 10 20
Truth or Consequences 57 75 55 87 / 20 60 10 10
Silver City 49 73 50 79 / 10 40 10 10
Deming 55 83 55 89 / 10 30 10 10
Lordsburg 52 82 53 87 / 10 10 0 0
West El Paso Metro 62 83 59 88 / 10 20 10 0
Dell City 60 84 52 89 / 0 30 0 10
Fort Hancock 63 87 55 91 / 10 10 0 10
Loma Linda 57 76 54 83 / 10 20 0 10
Fabens 63 86 57 91 / 0 10 0 0
Santa Teresa 57 82 55 87 / 10 20 10 0
White Sands HQ 62 81 61 88 / 10 40 10 10
Jornada Range 53 79 52 87 / 10 50 10 10
Hatch 55 82 52 90 / 10 50 10 10
Columbus 59 83 59 89 / 0 10 0 0
Orogrande 57 79 54 86 / 10 40 10 10
Mayhill 45 65 44 74 / 10 70 10 10
Mescalero 45 65 42 75 / 20 80 20 20
Timberon 44 66 42 73 / 10 60 10 10
Winston 47 69 47 80 / 30 70 10 10
Hillsboro 51 75 51 85 / 20 50 10 10
Spaceport 52 76 50 88 / 10 50 10 10
Lake Roberts 44 71 44 81 / 20 60 10 10
Hurley 47 76 49 83 / 10 30 10 10
Cliff 52 79 50 87 / 20 40 0 10
Mule Creek 51 74 50 82 / 20 30 0 10
Faywood 50 76 51 83 / 10 40 10 10
Animas 53 82 53 88 / 10 0 0 0
Hachita 54 82 54 87 / 0 10 0 0
Antelope Wells 52 82 52 87 / 0 0 0 0
Cloverdale 50 76 52 82 / 0 0 0 0
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...None.
&&
$$
FORECASTER...39-Aronson
Area Forecast Discussion
National Weather Service Peachtree City GA
1055 PM EDT Wed May 15 2024
.UPDATE...
Issued at 1052 PM EDT Wed May 15 2024
Other than a few light showers over the NE mountains, rain has come
to an end. The forecast remains on track, and no changes are planned.
/SEC
&&
.SHORT TERM...
(This afternoon through Thursday)
Issued at 232 PM EDT Wed May 15 2024
The main focus for this AFD is the showers ongoing over the area
with isolated thunderstorms. Overall, expecting very summerlike pop
up showers when it comes to this afternoon and evening, with no real
severe threat. After the upper level low centered over Tennessee
causing these showers moves to the east, your forecast should remain
dry until Friday. Gusty winds will be the main concern with gusts up
to 25mph this afternoon into the evening.
Hernandez
&&
.LONG TERM...
(Friday morning through next Tuesday)
Issued at 232 PM EDT Wed May 15 2024
The first 2 days of the extended period will likely be the majority
of the sensible weather for the extended period. The period begins
with a mid level disturbance located over the Mid MS valley early
Friday within the modest mid level flow of the jet extending back
over TX and Mexico. The tail end of the CAMS including the WRF FV3,
ARW, NAM3km and HRRR in fairly good agreement that a remnant or
decaying MCS could be approaching the region by early Friday..which
is entirely possible given upper support and surface based
instability available to the west of the region during the day on
Thu. If that`s the case, early Friday may be more of a rain shield
with embedded thunderstorms type of start to the day...which in turn
could limit the amount of destabilization that occurs during the day
Friday. The NAM3km tries to surge north much higher CAPE values
behind the departing MCS but fails to reach the southern CWA by the
end of the run Friday eve. Similar to the thinking in the previous
AFD, there is likely going to be a significant increase in
instability toward the gulf coast which may act serve as a deterrent
to convection further north and help keep the main axis of any MCS
development further to the south. All of that being said, there is
still a higher likelihood of widespread showers and a few embedded
thunderstorms north of any MCS which tracks to the south...hence NBM
guidance is ranging 60-80 pops late Friday through Saturday.
Saturday`s forecast remains a bit more uncertain given the
uncertainty in how Friday plays out, however, given the proximity of
the upper support over TN, modest mid and upper level jet energy,
sufficient deep and low level shear, there is a risk for severe
storms early through mid day Saturday....under the assumption that an
MCS to the south or early in the day doesn`t disrupt surface heating
processes. GFS soundings for W. GA midday Saturday certainly support
a severe risk, but given the many uncertainties in how things evolve
leading into Saturday, SPC correctly went the conservative route
with no outlined risk for Saturday. The CSU MLP severe risk outlined
for Day 4(Saturday) is in line with what the potential could be IF
other factors don`t come into play, which is possibly a 15% including
some Tor and wind risk. Stay tuned for updates.
Beyond Saturday...the main upper system from Friday/Saturday shifts
east and basically becomes stationary well offshore of the SE
coastline, but close enough to keep the region within a mid level NW
flow and pleasant weather through the remainder of the extended
period.
30
&&
.AVIATION...
(00Z TAFS)
Issued at 747 PM EDT Wed May 15 2024
Shower and thunderstorm activity has mostly been winding down over
the last hour or so. There are a few showers over N GA that have
increased in intensity a bit as some lingering shortwave energy
skirts by, but they should begin to weaken again with the loss of
daytime heating. Gusty winds are diminishing at this time. VFR
conditions are expected overnight with light W-NW winds. Light winds
will continue during the day Thu with few clouds.
//ATL Confidence...00Z Update...
High for all elements.
SEC
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 60 86 61 80 / 0 0 10 50
Atlanta 61 86 65 80 / 0 0 10 60
Blairsville 57 79 57 74 / 20 0 20 70
Cartersville 57 85 62 79 / 10 0 20 60
Columbus 62 89 67 84 / 0 0 20 60
Gainesville 61 85 62 77 / 0 0 10 60
Macon 63 88 65 84 / 10 0 10 40
Rome 58 86 62 80 / 0 0 20 70
Peachtree City 60 87 63 80 / 0 0 20 60
Vidalia 65 88 68 87 / 10 0 0 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...None.
$$
SHORT TERM...SEC
LONG TERM....30
AVIATION...SEC
Area Forecast Discussion
National Weather Service Flagstaff AZ
840 PM MST Wed May 15 2024
.SYNOPSIS...Scattered showers and isolated thunderstorms this
evening will diminish and shift eastward overnight. Rain and
thunderstorm chances remain Thursday for portions of northern and
northeast Arizona. High pressure returns Friday through the
weekend, resulting in breezy, warm, and drier conditions.
Unsettled weather returns next week.
&&
.UPDATE...Scattered showers persist across northern Arizona this
evening. Despite extensive cloud cover to end the day and the
loss of daytime heating, instability remains due to cooler air
aloft. CAPE values from the afternoon upper-air sounding (launched
at 4:30 PM MST) show around 300-400 J/kg with RAP presenting
200-500 J/kg across much of the area (at 8:30 PM MST), allowing
for ongoing thunderstorm activity. A few updates were made to the
forecast PoPs to track current observations and the latest CAMs.
Rain chances this evening will decrease overnight into the early
morning both with regards to coverage and probability. The low`s
center has progressed and now resides along the southern border of
Arizona. Water vapor satellite imagery shows drier air beginning
to enter the northwestern portion of the state as the trough and
low continue their trek eastward. These are early signs of
decreasing chances for showers and storms tomorrow. Don`t expect
as active of a day on Thursday with most of the rainfall and
convection occurring east of Flagstaff.
&&
.PREV DISCUSSION /433 PM MST/...The closed low along with a
longwave trough to the northeast are working in conjunction to
bring showers and thunderstorms to a good portion of northern
Arizona. Mostly light westerly winds are being impacted
significantly by the erratic gusts from the scattered storms. A
few of the stronger storms have produced wind gusts of 40 to 50
mph as outflow boundaries propagate in various directions. Be
aware, thunderstorms do not have to be directly overhead to bring
hazardous winds and/or lightning. These gust fronts continue to
trigger additional activity, tapping into the 250-500 J/kg of CAPE
across the area. Most of the gauges where precipitation has
fallen thus far have recorded only a few hundredths of an inch.
However, heavier showers are impacting localized areas along the
Mogollon Rim, Coconino Plateau, and Black Mesa with radar
indicated QPE of 0.5" to 1.25". Additional isolated strong storms
and rainfall will continue to be possible, especially over high
terrain.
Tonight through Thursday...The scattered showers and storms will
continue through the afternoon and evening hours before shifting
eastward as the low to our south tracks eastward. More isolated to
widely scattered showers and convection will linger overnight,
primarily relegated to Navajo County and Apache County. While the
dynamics will not be nearly as conducive for precipitation
Thursday, the ECMWF and GFS show a small shortwave ripple through
eastern Arizona. This wrinkle in the atmosphere along with left
over moisture will allow for a slight chance of rain. The best
chances will be along the Arizona/New Mexico border and White
Mountains (20-35%) that will extend along the Mogollon Rim as far
west as the Flagstaff area (10-15%). Much of western Arizona is
expected to remain dry tomorrow with diminishing cloud cover. Once
again, widespread heavy rainfall is not forecast with
precipitation amounts of less than 0.1" likely.
Friday through Sunday...By Friday, an upper-level ridge will begin
to form across the Southwest U.S., leading to a warming and drying
trend that will extend through the weekend. Afternoon highs will
be roughly 5 degrees above average each day. Winds do strengthen
out of the southwest, becoming breezy each afternoon as a longwave
trough to our north pushes against the ridge, tightening pressure
gradients. Overall, winds are forecast to remain below advisory
levels with gusts of 25 to 35 mph expected.
Monday through Wednesday...More unsettled conditions are expected
as models show a trough pushing into the region to start next
week. There is low confidence that this system will have the
moisture required to bring precipitation to Arizona. Anticipate
another increase in the already breezy west-southwest winds along
with temperatures cooling to near to just below seasonal norms.
These winds along with drier conditions will push us towards near
critical fire weather conditions once again. However, the rainfall
we are currently experiencing should help somewhat in this regard.
More updates to follow.
&&
.AVIATION...Thursday 16/00Z through Friday 17/00Z...Scattered
SHRA/TSRA continue this evening with brief periods of MVFR and
wind gusts up to 40 kts possible. Showers decrease by 03-06Z,
with a few lingering showers across eastern AZ overnight. Outside
of showers, VFR conditions continue. Varying wind directions
tonight with a trough passage, but more predominantly NW at 10-20
kts on Thursday.
OUTLOOK...Friday 17/00Z through Sunday 19/00Z...Mainly VFR
conditions expected with W to SW winds 10-20 kts each afternoon.
&&
.FIRE WEATHER...Tonight through Friday...Scattered showers and
thunderstorms will continue through tonight, becoming more isolated
on Thursday. Variable winds overnight, becoming west to northwest on
Thursday. Erratic outflow winds up to 40 mph possible in or near
showers and storms. Dry conditions return on Friday. South to west
winds 10-20 mph with afternoon RH values between 10-20%.
Saturday through Monday...Warmer and drier weather conditions are
expected through the weekend. Southwest to west winds 15-25 mph
gusting 30-35 mph, increasing to 35-40 mph on Monday. Afternoon
RH values will range between 5-15%, increasing to 10-20% on Monday.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PUBLIC...Mazon
AVIATION...MCT
FIRE WEATHER...MCT
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Indianapolis IN
947 PM EDT Wed May 15 2024
.KEY MESSAGES...
- Scattered showers and a few rumbles of thunder through early
evening across the south.
- Fog possible overnight to early tomorrow morning.
- Rain and storm chances return at times late Thursday through
Saturday.
- Above normal temperatures for this weekend through the middle of
next week.
&&
.FORECAST UPDATE...
Issued at 947 PM EDT Wed May 15 2024
- Decreasing cloudiness overnight; Patchy Fog expected.
Surface analysis late this evening shows low pressure in place over
West Virginia, exiting east. A weak ridge of high pressure was found
over IL and Indiana. Another area of low pressure was found over the
southern plains. GOES16 shows some diurnal CU across the area,
continuing to dissipate. Dew point temperatures across the area were
in the upper 50s and lower 60s.
Overnight, the weak surface high in combination with ridging aloft
is expected to build across Central Indiana. This will lead to
continued subsidence overnight and continued clearing. Models
suggest continued clearing skies overnight but dew point depressions
less than 2F. Thus with light winds and clear skies and these high
dew points expected, some patchy fog will be expected overnight.
Lows should fall to the middle and upper 50s. Overall, ongoing
forecast appears on track.
&&
.SHORT TERM (This evening through Thursday)...
Issued at 259 PM EDT Wed May 15 2024
The low pressure system that has brought ample rain since yesterday
is slowly making its way eastward leaving scattered showers across
the southern portion of the forecast area this afternoon. The rain
should fully exit central Indiana by late this evening. Brief upper
ridging will then move through, allowing a quick break in
precipitation before the next system moves in for the end of the
week.
Clouds will likely stick around for much of the night tonight with
model soundings showing persistent saturation at the top of the
boundary layer, but will have to keep an eye out for any locations
that do begin to clear as the recent rains will help to
supersaturate the low levels and may allow for some fog formation.
The low confidence that things will clear out enough for widespread
fog makes a Dense Fog Advisory seem a bit overdone at this time, but
will have to monitor things going into this evening.
Warmer temperatures are expected tomorrow with highs back into the
mid 70s to near 80. Another upper short wave behind the ridging will
bring additional rain later in the day tomorrow. Time of arrival is
still not clear but could arrive from the west as early as the 2 to
8pm timeframe.
&&
.LONG TERM (Thursday night through Wednesday)...
Issued at 259 PM EDT Wed May 15 2024
Thursday night through Saturday...
An approaching southern stream shortwave will keep elevated rain or
storm chances in the forecast towards the end of this week. The best
chance for rain looks to be late Thursday night through Friday
evening when the best forcing/moisture move across the Ohio Valley.
Anomalous moisture and warm rain processes could potentially lead to
another round of locally heavy rain. Considering grounds are already
saturated from heavy rain over the past 24 hours, there are elevated
flooding concerns if this scenario plays out. The one caveat to this
is that a strong MCS will likely move across the Gulf coast states
late Thursday into Friday morning which could limit deeper moisture
return further north. A few models have recently trended lower on
precipitation amounts for this reason.
Rain chances persist into Saturday as the aforementioned system
should still be centered near the Ohio Valley. Confidence is
somewhat limited on how long precipitation lingers Saturday due to
model discrepancies. The GFS is noticeably slower compared to other
guidance keeping elevated rain chances into Saturday night. Decided
to stick with the larger suite of models showing a more progressive
pattern with the system departing Saturday evening and decreasing
rain chances overnight.
Sunday onward...
Brief ridging building in Sunday should provide mostly dry
conditions, but can`t rule isolated diurnal convection, mainly over
SE counties as there could still be sufficient PBL moisture in
place. Confidence decreases some towards next week with model
solutions diverging. However, guidance is in general agreement that
upper level pattern switch from split-flow to more full-latitude
troughing across the western CONUS. The pattern looks to remain
active with multiple embedded shortwaves potentially moving through
next week. Look for rain chances to return late Monday PM and
persist through at least midweek.
At least a low end severe weather threat looks possible
Tuesday/Tuesday night as increasing instability and deep-layer shear
ahead of an approaching surface low could support organized
convection. CIPS Analogs and CSU machine learning are showing
increasing severe weather probabilities during this period. It is
still too early for exact details, but this will be monitored
closely over the coming days. Strengthening southerly flow should
help to warm temperatures well into the 80s early next week.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 837 PM EDT Wed May 15 2024
Impacts:
- VFR conditions expected this evening.
- IFR or worse visibilities possible late tonight in fog.
- A return to VFR after 1300Z on Thursday.
Discussion:
Wrap around diurnal clouds were slowly dissipating this evening as
low pressure east of the TAF sites continues to exit to the east.
Weak high pressure in place over the middle Mississippi valley is
expected build across Central Indiana allowing the clouds to
dissipate.
Low dew point depressions overnight along with clearing skies, light
winds and residual lower level moisture will allow for some fog
development late tonight. Have included some MVFR fog mention with
IFR tempo groups for now.
Fog will dissipate in typical diurnal fashion tomorrow morning, with
a SCT-BKN low end VFR cumulus deck likely to develop on Thursday.
HRRR suggests some scattered convection on Thursday afternoon as
diurnal highs area reached. For now have included a VCSH mention.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Puma
SHORT TERM...KF
LONG TERM...Melo
AVIATION...Puma
Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
642 PM CDT Wed May 15 2024
...New AVIATION...
.SYNOPSIS...
Issued at 221 PM CDT Wed May 15 2024
Pleasant and dry conditions will come to an end tomorrow as a few
systems cross the region. Showers and thunderstorms, some may be
strong to severe, are possible tomorrow evening and Friday.
Thursday`s potential for severe weather looks to be north of
Interstate 40 and Friday may be more widespread with the most likely
area across north Mississippi. High pressure settles in on Sunday
and temperatures will be on the rise and our first 90 degree day
will arrive early next week.
&&
.DISCUSSION...
(This evening through next Tuesday)
Issued at 221 PM CDT Wed May 15 2024
A nice cumulus field is depicted on satellite across the region as
skies gradually clear out as upper level ridging slides in.
Temperatures have risen to the mid to upper 70s this afternoon as
the sun shines through. A weak surface cold front is draped across
the TN/KY border at 1 PM. This cold front may have enough pull for a
few afternoon showers and thunderstorms across west Tennessee,
slight chance PoPs were carried near the Tennessee River to account
for any development. Skies will continue to clear this evening with
light winds making fog development possible. Radiational cooling
will enhance fog development mainly for areas near the Tennessee
River. Confidence is low in dense fog development.
An MCV on track across Missouri may bring a few strong, possibly
severe storms to the Mid-South tomorrow. Any development tomorrow
afternoon will most likely be confined to north of the I-40
corridor. This MCV does look to approach early tomorrow morning, but
it must act as a battering ram first to push the ridge out of the
way. By the time the MCV reaches the area, it will be running out of
daytime heating and diurnal stability trends. There however may be
enough low-level shear (31 kts 0-3km) for a strong to severe storm
late tomorrow evening with low confidence in the overnight severe
threat.
Model uncertainty has painted Friday as a few different outcomes. A
deep trough under southerly flow aloft will push across the
southeast from the southern plains. The strength of this trough will
be highly dependent on how long the decaying MCV takes to push out
of the Mid-South and if the atmosphere has enough time to recover.
Shear does still look to remain impressive and supportive of
updrafts, but instability could be lacking. The highest probability
for severe weather currently appears to be from far southeast TX
across much of LA and central/southern MS into western AL. Some
severe potential could extend farther north into the TN Valley, but
uncertainty regarding moisture return and the track of the surface
low. We will continue to monitor this active pattern.
The GFS is a bit pessimistic to push the precipitation activity out
of the region by Saturday morning while the ECMWF has dry conditions
returning Saturday morning. Due to the uncertainty, 20-30 PoPs were
carried for Saturday. High pressure begins to settle in Sunday, and
we could see our first 90 degree days of the season.
DNM
&&
.AVIATION...
(00Z TAFS)
Issued at 641 PM CDT Wed May 15 2024
No significant impacts expected this evening, with light winds
and VFR. Will need to watch an area of SHRA/TSRA lifting east
across north central AR. None of CAMs initialized this activity
earlier and recent runs of the HRRR squash it quickly, despite
30-40KT of bulk sheer. This may indeed happen, given significantly
weaker low level flow over eastern AR by 03Z.
Overnight, patchy fog will develop where skies partially clear.
Bulk of SHRA/TSRA to arrive at MEM after 06z Friday, beyond the
TAF period. Decided to include a PROB30 for TSRA for late Thursday
evening, given the potential for impacts.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...DNM
AVIATION...PWB
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1000 PM EDT Wed May 15 2024
.SYNOPSIS...
A cold front will sweep across ENC tonight with high pressure
building in behind it, keeping Thursday dry. Another low
pressure system impacts us this weekend.
&&
.NEAR TERM /Through Tonight/...
As of 10 PM Wed...Severe threat has since ended, and in it`s
wake an MCV has formed off the NC coast with a stratiform rain
area with some embedded thunder in it`s wake. Thus will hang
onto likely showers with chc thunder through the next few hours,
before showers taper off and move offshore. Rest of the night is
quiet.
Prev disc... As of 707 PM Wed...Severe storms that formed over
the last two hours are beginning to weaken over the past 30 min,
and should cont to do so. Still, some small hail and gusty
winds can be expected with any remaining storms through around 9
pm this evening, before storms weaken to showers and eventually
dissipating after midnight. Remainder of the night will be
quiet, with some patchy light fog developing late.
Prev disc...As of 3:30 PM Wednesday...Latest surface analysis
shows the cold front draped nearly parallel to Core Banks. This
boundary has been a source of lift for the showers and
thunderstorms that have moved across the area over the past
several hours.
All convection within the FA has waned, but a second round is
expected later this afternoon and evening (especially south of
HWY 64) due to a cold front and mid-level low moving across the
area. Storms that develop have the potential to become strong
to severe given the RAP mesoanalysis showing 1000-2000 J/kg of
MLCAPE, 50-55+ kt of effect shear, and mid-level lapse rates
around 6 C/km. As a result, a Severe Thunderstorm Watch is in
effect until 8 PM for Lenoir, Pamlico, Jones, Craven, Duplin,
Onslow, and Carteret Counties. The primary concerns with these
storms are damaging wind gusts and hail. The severe threat will
decrease after sunset, but strong to severe storms are still
possible through the evening. Convection will decrease after
midnight and lows will drop to the low 60s across the area.
&&
.SHORT TERM /THURSDAY/...
As of 4 PM Wednesday...A nice day is in store as we settle into
the post-frontal air mass and upper ridging builds in. Cloud
cover will hang around through the day, but we`ll be dry with
highs in the upper 70s along the coastal plain and low 70s along
the OBX.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 430 AM Wednesday...High pressure builds in Thursday night
into Friday but another low pressure system will impact the
area this weekend. High pressure builds in early next week.
Thursday through Friday...Upper ridging builds in from the
west Thursday with a vertically stacked low off the Mid-Atlantic
coast slowly moving eastward. Lowered PoPs to below mentionable
with most guidance now indicating dry conditions and model
soundings showing only a shallow saturated layer above 850mb
and very dry well mixed conditions below that. If any showers do
develop, they will likely only produce virga. Ridging crest
over the area Friday with mainly dry conditions expected but
will see increasing clouds as the next system approaches and
could see an isolated shower move in from the west late in the
day.
Friday night through Sunday night...A complex low pressure
system will impact the region through most of the weekend. A
southern stream wave will transport ample gulf moisture into
the region Friday night into Saturday with sfc low pressure
moving across the region late Saturday or early Sunday. The
system then transitions into a vertically stack low as it slowly
pushes across the Mid-Atlantic and off the coast through the
latter half of the weekend. As with most cut-off systems, there
are differences among the models with the evolution, timing and
track with this system but unsettled weather will impact the
region through much of the period.
Monday and Tuesday...The upper low slowly pulls away from the
area early next week with high pressure building in from the
west with generally dry conditions expected.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
SHORT TERM /through Thursday/...
As of 707 PM Wed...A mixed bag of flight categories is expected
over the next 24 hours. Showers and thunderstorms that
developed south of Hwy 70, will be ongoing through the mid
evening, and eventually dissipate by midnight. With the today`s
rainfall and overnight winds expected to go light to calm, fog
development cannot be ruled out, but the most likely scenario
will be IFR to possibly LIFR stratus. Conditions will improve to
VFR by mid- morning.
LONG TERM /Thursday through Sunday/...
As of 445 AM Wednesday...Pred VFR expected Thursday through
Friday with high pressure building into the area. Another
low pressure system will impact the area through the weekend
bringing periods of sub-VFR conditions Friday night through
Sunday.
&&
.MARINE...
SHORT TERM /Today and Tonight/...
As of 4 PM Wed...Poor boating conditions continue with 4-6 ft
seas and SW winds around 10-15 kt, veering to the NW overnight.
SCA conditions should cease by early tomorrow morning with seas
decreasing to 3-5 ft.
LONG TERM /Thursday through Sunday/...
As of 5 AM Wednesday...Low pressure off the Mid-Atlantic will
slowly push away from the area Thursday with high pressure
transitioning across the waters on Friday with conditions
expected to remain below Small Craft Criteria. A complex low
pressure system will impact the region Friday night through
Sunday bringing unsettled weather through the period. Guidance
for the most part keeping conditions below SCA criteria through
the weekend but cannot rule out a period of low end SCA mainly
late Saturday/Saturday night. The best opportunity for SCA
conditions will be late in the weekend or early next week as low
pressure deepens as it pulls offshore. There are differences
among the models the timing and track of this system, so be sure
to follow updates as details come into focus.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...Small Craft Advisory until 2 AM EDT Thursday for AMZ158.
&&
$$
SYNOPSIS...MHX
NEAR TERM...TL/OJC
SHORT TERM...OJC
LONG TERM...SK/SGK
AVIATION...SK/TL
MARINE...SK/OJC
Area Forecast Discussion
National Weather Service Las Vegas NV
750 PM PDT Wed May 15 2024
.SYNOPSIS...Scattered showers and isolated thunderstorms will
pose a gusty wind threat for areas along and south of Interstate 15
today. The work week ends warm and dry, with Las Vegas making a run
at 100 degrees on Friday. Gradual cooling and increasing winds ensue
this weekend and into next week as low pressure develops over the
region.
&&
.UPDATE...Scattered showers and isolated thunderstorms across the
Mojave Desert this afternoon are beginning to wane with the sunset.
The low levels remained very dry, with DCAPE measured around 1700
J/kg in the 00Z sounding, so most showers failed to produce enough
rain to reach the ground. The exception to this was the higher
terrain of Mohave County. Gauges on the Hualapai Mountains measured
between 0.08 and 0.16 inches of rain today. Some cells produced
frequent lightning as well as gusty winds between 20 and 30 mph, but
no cells approached severe criteria this afternoon. Remnant showers
in eastern San Bernardino and central Mohave counties will continue
to dwindle over the next few hours. No changes made to the forecast
this evening, as it looks to be in good shape.
&&
.PREVIOUS DISCUSSION...1245 PM PDT Wed May 15 2024/
.SHORT TERM...Today through Friday.
Main story today will be the isolated-to-scattered showers (and
possibly a storm or two) along and south of the I-15 corridor. A
vorticity max diving south through Utah will interact with remnant
moisture associated with the closed low over the San Diego / Baja
California area. Convective initiation will favor the local high
terrain, with outflow winds more likely to move into surrounding
valleys than actual precipitation. As moisture (particularly in the
low-levels) is so limited, not concerned with heavy rain or flash
flooding from this activity. Instead, any threat posed by convection
will likely be from lightning or outflow winds. RAP forecast
soundings show deep, inverted-V profiles with DCAPE of 1500+ J/kg,
supporting efficient evaporation in the sub-cloud layer and
enhancing downdraft potential. This is reflected in the 12z HREF
probabilities of 30+ knot winds, which paint a wide swath of 10-30%
chances along and south of I-15, along with a small area of 50%
chances in southern Mohave County this evening as activity
consolidates there. Rain chances completely exit our CWA around
midnight, ushering in a dry period that lasts at least a couple days.
This dry period ensues because high pressure begins to build over
the region. 500mb height anomaly charts show modest positive
anomalies over the W/SW US on Thursday and Friday, sandwiches
between a cutoff low in the Eastern Pacific and a shortwave over the
Northern Rockies. These height rises and the general "breeziness" of
the zonal/NW flow pattern will allow Las Vegas to make a run at its
first 100 of the year on Friday. Latest NBM probabilities of
reaching 100 degrees stand at 50% and Death Valley has a 25% chance
of reaching 110. Needless to say, it`s going to be pretty warm out
there, with Minor-to-Moderate HeatRisk across the area.
.LONG TERM...This weekend into next week.
As an additional shortwave enters the Pacific Northwest and the
eastern Pacific low begins to move towards shore, our ridge will
slowly break down over the weekend. This allows temperatures to
gradually cool while breezy conditions persist. By the start of the
work week, ensemble guidance is in pretty good agreement, phasing
the eastern Pacific low with the Pacific Northwest shortwave. As
this occurs, temperatures return to seasonal values (possibly a few
degrees below normal) and winds increase. The best chance of wind
impacts looks to be across our western deserts, with 50-80%
probabilities of 40+ mph winds Saturday - Monday. Elsewhere,
impactful wind chances peak on Monday with generally 25-50%
probabilities. At least some degree of troughing is forecast to
linger across the Western US through most of next week. The depth
and southward extent is less clear, which will impact temperatures
and winds during this time. This uncertainty is evident in NBM box-
and-whisker plots of high temperatures, with a ~10 degree spread
between the 25th and 75th percentiles. The same plots for peak wind
gusts show 15-20 knot spreads. However, we can generally expect
temperatures to be within a few degrees of normal and at least
breezy conditions to persist through most of the week.
&&
.AVIATION...For Harry Reid...In the absence of any convective
influence, expecting light winds to persist from a NNW - NNE
direction. However, there is potential outflow winds from vicinity
precipitation to reach the airport. The first chance comes this
afternoon between 21z and 00z, and is dependent on if anything can
develop off the Sheep range to the north. The second chance comes
later this evening (~06z) from distant convection in SW Utah. This
second wave seems to have more model agreement (roughly 60% chance)
and would likely be stronger. Latest NBM guidance suggests gusts up
to 20 knots are possible. With both outflow scenarios, wind
direction should be from the N or NE. By 09z, any outflow influences
should cease, leaving light N breezes less than 10 knots to persist
through the night, becoming NE tomorrow morning. FEW-SCT clouds aoa
10kft this afternoon and evening, becoming clear overnight.
For the rest of southern Nevada, northwest Arizona and southeast
California...Isolated to scattered showers and storms may influence
conditions (mainly winds) at sites in the Las Vegas and Colorado
River Valleys this afternoon and evening. In the Vegas Valley,
outflow potential exists this afternoon with any vicinity
convection, with a better chance (~60%) late in the evening as
outflow from distant activity tries to move into the valley. Any
outflow winds should be from the N or E. Similar story for KEED and
KIFP, though the outflow direction is more likely to be from the
west this afternoon and east this evening. Outside of convective
influences, these sites should see typical light and diurnal wind
patterns. At KDAG, light NE winds this afternoon with the typical
westerly push arriving around 02z with gusts of 20-25 knots. At
KBIH, north winds increase to 15-25 knots this afternoon, weakening
overnight. VFR conditions prevail with FEW-SCT clouds aoa 10kft.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Varian
DISCUSSION/AVIATION...Woods
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