Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/13/24
Area Forecast Discussion
National Weather Service La Crosse WI
1033 PM CDT Fri Jul 12 2024
.KEY MESSAGES...
- Multiple rounds of storms from Saturday through Monday night.
Some storms will be strong to severe with damaging wind gusts
being the primary threat. Higher probabilities for severe
weather are late Saturday and Monday.
- Hot and humid this weekend with highs in the upper 80s and
lower 90s. Widespread heat indices in the middle to upper 90s
with some areas reaching 100 on Sunday.
- Cooler and drier conditions are expected by Tuesday for much
of the upcoming week with highs in the middle to upper 70s.
&&
.DISCUSSION...
Issued at 121 PM CDT Fri Jul 12 2024
Storm Chances Tonight and Tomorrow Morning:
As we head into the overnight hours and tomorrow morning, a more
zonal mid-level flow pattern takes shape as a broader ridge builds
to the west. Consequently, guidance increases theta-e in the low-
levels as this pattern change occurs. This theta-e advection
with increasing MLCAPE (1500-3000 J/kg in the 12.09z RAP) by mid
morning would suggest some convective initiation. However, with
fairly meager effective bulk shear (20 kts or less in the
12.09z RAP), would not expect cells to be able to maintain in an
organized manner. Furthermore, with the relatively weaker
forcing regime, the latest CAMs generally have minimal
convective coverage. However, given the more robust instability,
particularly later in the morning, decided to hold onto some
precipitation chances (15-25% chance) during this timeframe.
Given the robust instability later into the morning and
afternoon would not be able to completely rule out some gusty
winds or small hail if any stronger cells manifest, mainly
across.
Severe Potential for Saturday through Monday:
A challenging forecast lies ahead for the weekend and early next
week as a few rounds of storms will be possible with some severe
weather potential. As we head into Saturday evening, guidance
depicts a robust thermal ridge beginning to advect into our region
with a more stout cap inversion in place where the 700mb 12C
isotherm can reach. As this occurs, guidance depicts a
marginally increasing low-level jet with accompanying 850mb
moisture transport pushing into northwestern WI/eastern MN,
which almost all of the CAMs agree will be an instigating
mechanism to develop an MCS later Saturday along with a subtle
piece of shortwave energy. The main conundrums with this setup
are the difference is the uncertainty in timing for when this
MCS gets going and exactly how far northeast the thermal ridge
axis is able to build into our local area which would be
important for how strong the cap ends up. Another consideration
as well is a secondary nose of 850mb moisture transport that
develops through southern/central WI during the evening that may
try to instigate some discrete convection ahead of the
aforementioned MCS as shown in the past couple HRRR runs. While
shear profiles are fairly lackluster, fairly robust MUCAPE
(3000-4000 J/kg) in the 12.09z RAP would indicate more pulse
convection with maybe some hail in stronger updrafts.
Overall, would say confidence for seeing this MCS is higher along
and north of the I-94 corridor with confidence decreasing south and
west where probabilities in the grand ensemble (GEFS/EC
ensemble/Canadian ensemble) begin to increase for 700mb temps of 12C
or greater (60-80% over NE IA). However, changes in how the thermal
ridge manifests will have implications for both timing and location
of this convective complex. Generally though, would expect damaging
wind gusts would be the primary concern with the 12.12z HRRR Neural
Network Probabilities showing higher probabilities (40-60% chance
within 40 km of a point) for 50 kt wind gusts around the I-94
corridor and lower probabilities further south and west. Rainfall
amounts in the 12.12z HREF probabilities for 1" or greater are
fairly modest (40-60% chance) across north-central Wisconsin, with
the ensemble max having localized amounts of around 2-3". However,
with the fairly progressive nature of this event would expect
flooding concerns to be fairly isolated.
Sunday generally has trended more on the marginal side for any
severe weather with the aforementioned thermal ridge firmly in place
with a strong cap noted across much of the region. With the general
absence of any pieces of shortwave energy, the main forcing
mechanism for any convection during the day on Sunday would be
residual outflow boundaries from prior convection overnight
Saturday. But again with still remaining questions for how Saturday
night convection will manifest, confidence still remains low for
convective trends on Sunday. Overall would anticipate with the
stronger cap that a drier trend would be more likely to resolve but
will hold onto some precipitation chances for now.
We keep this unsettled pattern continuing into Monday and Monday
night as deterministic guidance (12.12z NAM/GFS/EC) hints at some
shortwaves in the flow along the southern periphery of a broad upper-
level synoptic trough diving south from Canada. Thermodynamics with
any convective system that may occur is challenging as the
previously mentioned cap begins to wane throughout the day with
increasing destabilization. Consequently, if the forcing regime is
more favored during the morning hours would keep convection elevated
with a tendency to be more surface-based during the
afternoon/evening where the 12.12z NAM/GFS tries to erode the cap
which would favor the potential for damaging wind gusts with the
lack of a stable layer. Overall, shear profiles in deterministic
guidance with the 12.12z NAM having 50-60 kts of 0-6km shear by 21z
Monday. Therefore, would think better organization with storms would
be possible later into the day. Certainly a very tricky forecast
across the board and will have to monitor how the convective
allowing models trend over the next couple of days.
Heat this Weekend:
With the aforementioned thermal ridge building into our area this
weekend, zonal to northwesterly flow coupled with
south/southwesterly surface flow will allow temperatures to trend
above normal for the weekend and Monday. Sunday currently appears to
be the warmest of the three days with the 12.13z NBM having a
25th to 75th percentile spread for highs at La Crosse of 92 to
94 degrees. With southerly flow helping aid dewpoints in the
lower to middle 70s on Sunday, pretty good consensus that heat
indices will near 100 degrees for some locations. Certainly will
be one of the hotter days we have had so far this summer.
Saturday and Monday will likely trend warmer as well however,
with convection around probably will trend slightly cooler but
still above normal with heat indices in the lower to upper 90s.
Drier, Cooler by Tuesday Through The End of the Week:
As the aforementioned broader upper-level trough begins to pivot
eastward towards the middle of the week, northerly flow will help
aid in cooler air to be advected into our region. Guidance generally
agrees that temperatures will trend above normal with the 12.12z
grand ensemble (GEFS/EC ensemble/Canadian ensemble) having an inter-
quartile range of 73 to 77 degrees for highs on Wednesday at La
Crosse with similar degree of confidence throughout the rest of the
week. Additionally, with subsidence under a broad surface high
pressure that the 12.12z GFS/EC pushes into our region during the
second half of the week, would expect minimal precipitation chances
from Wednesday through Friday.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1028 PM CDT Fri Jul 12 2024
VFR expected through most, if not all of the TAF period. Initial
calm conditions at 13.06Z TAF issuance with SCT-FEW mid level
deck spread from southwest to northeast early this morning.
Subsequent impacts will be the potential for a line of storms
this afternoon and evening. Highest confidence, albeit limited,
has a line sagging south through the Upper Mississippi River
Valley into the evening hours. Highest confidence remains
farther north, north of the Interstate 94 corridor. Therefore,
most likely locally impacted small airport would be KMDZ.
Farther south towards KBCK is where confidence wanes. Given the
low confidence, have not included in either TAF (KLSE/KRST) at
this time. Primary hazard would be damaging winds with a
secondary hazard of large hail possible.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor
AVIATION...JAR
Area Forecast Discussion
National Weather Service Binghamton NY
759 PM EDT Fri Jul 12 2024
.SYNOPSIS...
Rain showers and a few isolated thunderstorms develop this
evening and overnight mainly across NE PA and into the Southern
Tier. Hot and humid conditions are expected through this weekend
with heat indices approaching 100 degrees in the afternoon.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
745 PM Update...
Latest radar, satellite and model data is trending a touch east
with the rain and clouds with the coastal trough overnight into
Saturday. Adjusted sky cover, PoPs and QPF to show this trend.
Currently clouds are in place over the Catskills, Poconos and
portions of the Mohawk Valley/eastern Central NY. A few rain
showers are on radar east-southeast of Scranton across the
Poconos of NE PA. The HRRR and 3km NAM keep this general theme
going all night, with the highest PoPs now in the forecast right
along our CWA border for locations such as Hazleton--Daleville
and Milford PA. Further back to the north and west expect partly
cloudy skies overnight, with patchy for development and perhaps
a slow moving pop up shower. By daybreak Saturday and through
much of the day, the main area of rain now looks to be east of
our forecast area with just a slight chance for a pop up shower
or thunderstorm. Morning clouds east of Binghamton gradually
giveway to mainly sunny skies. Overall, for much of the area it
is shaping up to be a nice Saturday weather-wise for mid-July.
It will be very warm with highs in the 80s to near 90 and rather
humid conditions.
530 PM update...
With some tropical moisture streaming northward and a 500 mb
shortwave moving through tonight there will be some scattered
rain showers and isolated thunderstorms developing after sunset.
The best chances are in NEPA into the Southern Tier of NY as
that is where the deepest moisture is. Despite a through moving
through tonight, tomorrow is looking warmer as there will be
less clouds around and warmer air begins to advect in aloft.
Chances of showers and and thunderstorms will return in the
afternoon with the heat and humidity leading to some
instability.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
520 PM update...
Weak zonal flow on Sunday with warm air aloft will lead to
warmer high temperatures and dew points near 70 so heat indices
will rise into the 90s to near 100 in some of the deeper river
valleys of NEPA. With the zonal flow, upstream MCS`s in the
northern plains could lead to quick moving embedded shortwaves
that could trigger thunderstorms if an MCS can form tomorrow.
Right now chances of precipitation were kept low given the
uncertainty in the evolution of the convection tomorrow.
Monday is looking hot as well with similar highs as Sunday but
dew points will be 3 to 5 degrees higher making it more muggy.
Once again with the heat and humidity, instability develops
across the region and upstream convection could supply a trigger
to get convection going in the afternoon. Shear is fairly weak,
only around 20 knots but given the high instability, there is a
threat for a few microburst if thunderstorms are able to
develop.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
520 PM update...
The heat continues into Tuesday with potentially the warmest
temperatures and highest dew points. Much of the region reaches
the mid 90s to mid 100s for the heat index. There is potential
for it to be a little cooler if an approaching shortwave can
speed up and provide more clouds as well as develop showers and
thunderstorms earlier in the day. As the shortwave moves through
Tuesday night into Wednesday, there will be good chances for
widespread showers and thunderstorms. Shear does increase to 30
to 35 knots in ensemble means so timing of the passage will have
to be watched. Once the shortwave passes east mid week, cooler
and drier air advects in helping make for a better end to the
week with seasonable temperatures, lower dew points, and mostly
sunny skies.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions at most terminals expected through 6Z tonight
though AVP will likely have some showers around through most of
the night. Fog begins to develop after 6Z with AVP and ELM with
the best chance at seeing fog if the skies remain clear at ELM
and if there ends up being more rain at AVP. BGM may see some
rain showers late that could cause some MVFR restrictions.
Tomorrow is looking VFR at all terminals once the fog clears in
the morning.
Outlook...
Saturday night...Patchy valley fog may bring occasional
restrictions, especially at KELM. Otherwise mainly VFR.
Sunday...Mainly VFR.
Monday through Wednesday...Scattered showers and thunderstorms
may bring occasional restrictions; otherwise mainly VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...AJG/MWG
NEAR TERM...AJG/MJM/MWG
SHORT TERM...AJG/MWG
LONG TERM...AJG/MWG
AVIATION...AJG
Area Forecast Discussion
National Weather Service Bismarck ND
1015 PM CDT Fri Jul 12 2024
.KEY MESSAGES...
- Isolated to scattered severe storms are possible across all
of western and central North Dakota tonight. Hail to the size
of golf balls and winds up to 70 mph will be the main hazards.
- Very warm temperatures through the weekend, with a Heat
Advisory in Dickey and LaMoure counties 1 PM to 8 PM
Saturday.
- Isolated to scattered severe storms are possible late Saturday
afternoon and into the night. Hail to the size of golf balls
and damaging winds up to 70 mph will be the main hazards. A
tornado or two is possible northwest.
- Isolated to scattered severe storms will be possible once
again on Sunday.
&&
.UPDATE...
Issued at 1015 PM CDT Fri Jul 12 2024
Removed Hettinger, Stark, Dunn and Ward counties from the Severe
Thunderstorm Watch. Currently have two severe thunderstorm
warnings out and overall the severe threat has diminished
somewhat, but still existent. Currently watching a stronger
warned supercell in Oliver county moving southeast toward
eastern Morton and western Burleigh counties. Will also need to
continue to monitor convection in northeastern Montana that is
approaching northwest ND.
UPDATE
Issued at 820 PM CDT Fri Jul 12 2024
Quick update to adjust pops to better match radar trends,
blended with most recent model guidance.
UPDATE
Issued at 736 PM CDT Fri Jul 12 2024
Severe thunderstorm watch #521 has been issued for most of
central and part of southwest ND, in effect until midnight CDT.
Also adjusted key messages to reflect larger hail and wind
potential with these storms tonight.
UPDATE
Issued at 723 PM CDT Fri Jul 12 2024
Severe thunderstorm watch for much of central ND will be issued
shortly, after coordination with SPC.
There has been a slight uptick in convection over the past hour
or two with 3 storms currently having severe thunderstorm
warnings in place. Water vapor imagery shows flattened broad
scale ridge in place with an embedded shortwave trough nearing
the MT/ND border, and likely supporting convective trends. SPC
mesoanalysis continues to show MLCAPE of 3000-4500 J/KG with the
most recent convection firing along the CAPE gradient coincident
with a weak frontal boundary. The HRRR continues to carry the
convection eastward through the state tonight, but continues to
be uncertainty in how it will actually evolve. Bulk shear
(0-6km) continues to range 30-40kts, mainly across the west.
&&
.DISCUSSION...
Issued at 345 PM CDT Fri Jul 12 2024
Currently mostly clear skies are found across the state, with
some diurnal cumulus in the James River Valley. Scattered
thunderstorms have developed in far northwest North Dakota along
a weak surface front. Ahead of this front is a surface trough
orientated north/south across the west central part of the
state. Aloft the ridge is still flattening with a small
shortwave in eastern Montana. This wave will move east through
the evening, combining forces with the cold front, kicking off
convection. At the surface with this wave is much drier dew
points. Currently dew points in North Dakota are in the 60s and
70s. With these higher dew points CAPE values are very high,
however the is a strong cap in place, via our morning soundings.
This would be why there is no diurnal cumulus elsewhere. Models
have a pseudo-dry line moving in from Montana behind the cold
front this evening that storms will form on. As of 3pm CT
there`s a storm trying to go up in southern Dunn county. This
will be a good indicator on the status of the cap. This storm so
far has only produced a quick weak tornado, no hail. Most CAMs
are very different a few isolated cells turning into an
organized line moving through the state, then the rest of them
keep the isolated cells. So if the line happens wind will be
more of a concern, especially with dew points dropping. That
will make an inverted V sounding, which is ideal for severe
wind. Otherwise if isolated cells, it will mostly be hail
around 1 inch. Shear is not very high, it looks to be around
20kts. CAPE is much high in the moist air but then drops off
rapidly west of the river where the storms will be forming.
Confidence in the storm mode is relatively low for a few hours
before the event unfortunately. The forecast may have lower PoP
values than expected because of this uncertainly in storm mode
and timing. The general timing for the main show is 23z
(starting in the west) to around 08z (ending in the east).
Wildfire smoke will continue to affect the upper atmosphere,
really just affecting the color of the clear sky you see.
Saturday is more of the same with possible severe storms. SPC
has a slight risk (level 2/5) across most of the area. Most
CAMs have a line moving in from Montana around 02z. CAPE looks
to be around 1500 J/kg with shear values around 40kts. 0-3km
shear is around 30kts, so wind will be a bigger concern if the
storm mode is a line, otherwise hail would be bigger in size
around golf balls. Sunday another chance of severe storms are
possible. SPC has a marginal from Williston to Bismarck over to
the Red River Valley. There is also a slight risk in the north
central down through Harvey and east. Currently for Sunday CAPE
and shear is very high in the slight risk area. We`ll see how
that evolves.
Saturday will be the warmest day with the highest humidity. The
James River Valley will be the warmest spot. We have issued a
Heat Advisory for just Dickey and LaMoure counties from 1pm to
8pm Saturday for heat index values as high as 103 degrees.
The ridge through the weekend will continue to flatten and turn
zonal with slight waves of energy moving through. High
temperatures through the weekend will slowly cool to the 80s by
Monday as a front and wave dip down from Canada. Temperatures
look to stay in the 80s with a big upper low spinning farther
up in Canada before dipping into the Great Lakes Wedneday. This
will put us in northerly flow, aiding to the slightly cooler
temps.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 647 PM CDT Fri Jul 12 2024
The main issue involves scattered thunderstorms, some severe
slowly moving through western and north central ND. Already
updated KMOT for a thunderstorm moving through the area, and
another thunderstorm approaching KDIK. Otherwise, due to overall
coverage kept VCTS in the other locations.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM to 8 PM CDT Saturday for NDZ048-051.
&&
$$
UPDATE...JNS
DISCUSSION...Smith
AVIATION...JNS
Area Forecast Discussion
National Weather Service Charleston SC
1007 PM EDT Fri Jul 12 2024
.SYNOPSIS...
A weak front will meander across the area through Saturday.
Atlantic high pressure will then rebuild across the area while
a surface trough exists inland Sunday through the middle of
next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Per recent SPC mesoanalysis, still a bit of instability out
there (in excess of 2K J/Kg MLCAPE) and limited CINH with
spotty convection continuing to bubble up along any random
boundary. SPC RAP forecasts do show increasing CINH as we get
into the overnight hours suggesting inland convection will
eventually fizzle out. But PoPs were held through the evening
and into the early overnight hours accordingly.
Meanwhile, some additional showers/storms could continue or
develop off the Charleston coast throughout the night, some of
which could skirt the Charleston County coastal areas.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Saturday: Aloft, a mid-lvl ridge will gradually strengthen across
the Southeast United States. At the sfc, weak low pressure across
southern areas should gradually nudge west during the day while a
weak front/stalled boundary lingers nearby. The pattern will favor a
slightly weaker onshore wind compared to the previous day, but will
continue to advect moisture characterized by PWATs in excess of 2.0
inches across a large portion of the area. An afternoon sea breeze
interacting with a the nearby front/boundary should become the main
focusing point for afternoon convection, with greatest precip
coverage across the Tri-County Area away from the beaches mid-late
afternoon. Coverage and intensity of rainfall should be less than
the previous day with subtle forcing in place, and precip totals
should generally average around 1/2 inch or less. However, a few
locations could see slightly higher precip amounts during a
thunderstorm. Expect precip coverage to quickly diminish during
evening hours with the loss of diurnal heating.
Outside/before precip, warm and humid conditions are anticipated
across the area, with a few locations potentially experiencing heat
index values between 105-109 for an hour or two along and east of
the I-95 corridor, mainly across Southeast South Carolina early to
mid afternoon. Some uncertainty in the duration of highest heat
index values comes into question given precip developing across the
same area by peak diurnal heating hours. However, sfc temps should
still peak in the mid-upper 90s away from the coast alone, warmest
across Southeast Georgia. Overnight lows will remain mild, generally
in the mid 70s inland to upper 70s/lower 80s near the coast.
Sunday and Monday: Aloft, mid-lvl ridging will persist, but show a
slightly weaker signal while a series of subtle h5 shortwave pass
along the base of a low amplitude trough across the Mid-Atlantic
states. At the sfc, what is left of weak sfc low pressure and a
nearby front dissipates with the pattern becoming more summerlike in
nature with lee troughing across the Midlands and high pressure
extending across the western Atlantic. These features should provide
sufficient forcing and/or a focusing mechanism for afternoon
convection in a moist environment (PWATs around 2 inches) just
inland to the area, before a westerly flow between the mid-upper
trough to the north and a ridge to the southwest nudges activity
across the local area. Some enhancement along a sea breeze shifting
inland is possible each day, at least in regards to carrying chances
of showers and thunderstorms across the entire area. A stronger
thunderstorm can not be ruled out, but overall organized severe
weather potential remains low. Outside of precip, conditions will
become quite warm, with afternoon highs in the mid-upper 90s away
from the coast. A few locations could even touch 100 degrees far
inland each afternoon. The combination of a weak downsloping wind
aloft and low-lvl mixing during the afternoon should lower sfc
dewpts across areas experiencing the warmest temps well inland, but
many areas could experience heat index values that support Heat
Advisories each afternoon, mainly along and east of the I-95
corridor. Overnight lows will remain mild, generally in the mid 70s
inland to upper 70s/lower 80s near the coast.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Ridging will gradually build across the Southeast United States,
while weak shortwave energy ripples across the Mid-Atlantic states
along the southern periphery of a mid-level trough. At least
scattered showers and thunderstorms will be possible each afternoon,
typical of a summerlike pattern. Outside of precipitation, hot and
humid conditions are forecast into mid week. Heat Advisories could
be required Tuesday through Thursday, until a front approaches the
area late week with greater shower/thunderstorm coverage locally.
Heat Index values could even approach Excessive Heat Warning
criteria (113F) across portions of the forecast area on Tuesday and
Wednesday.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Showers and thunderstorms have diminished greatly across the
region, although showers may continue to percolate through the
evening hours. Also, there could be some additional showers and
thunderstorms that persist or develop off the Charleston coast
that make a run toward the coast overnight through early
Saturday. However, chances are too low to include in the
terminal forecasts at this juncture.
Saturday will see another round of showers and thunderstorms
develop in the afternoon and the latest forecast will feature
VCSH from 18Z onward.
Extended Aviation Outlook: Scattered afternoon showers/thunderstorms
could produce tempo flight restrictions at CHS/JZI/SAV terminals
each afternoon through early next week.
&&
.MARINE...
Tonight: South to southeast winds are favored through tonight
as weak low pressure and an associated surface boundary shifts
further inland. Speeds will be in the 10-15 kt range. Seas will
average 2-4 feet, with some 5 footers across the outer portions
of the Charleston County nearshore waters.
Saturday through Tuesday: A pinched gradient could develop over the
marine waters through early next week as high pressure persists
across the western Atlantic and a trough lingers inland. However,
conditions are expected to remain below Small Craft Advisory
criteria. In general, southerly winds will be in place with
temporary increases to around 15 kt, mainly near the coast where sea
breeze circulations develop, then shift inland. Seas will range
between 2-4 ft.
Rip Currents: Moderate SSE swell directed mainly north of Cape Fear
will work into Charleston County coast today. The modest increase in
swell will bump the rip current risk to Moderate for the Charleston
County beaches.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...Adam/ETM
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...Adam/DPB/ETM
MARINE...DPB/ETM
Area Forecast Discussion
National Weather Service Cheyenne WY
942 PM MDT Fri Jul 12 2024
.KEY MESSAGES...
- Very hot temperatures are likely across all of southeast
Wyoming and the western Nebraska Panhandle this weekend
through early next week. A Heat Advisory has been issued for
portions of southeast Wyoming Friday afternoon, and for all
areas east of the Laramie Range for this weekend.
- Widespread precipitation possible Monday and Tuesday with a
brief cooldown Monday through Wednesday. Warmer, drier
conditions return Thursday onward.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 216 PM MDT Fri Jul 12 2024
Most likely looking at a quiet, but hot afternoon and evening across
the CWA. Hi-Res guidance has trended precipitation chances down from
earlier runs. Lack of any real cumulus field across the plains and
high terrain is also indicative of decreased precipitation chances.
There is a bit of a cumulus field over and south of the Black Hills,
which could lead to a Dawes County clipper later this afternoon and
again later tonight per the HRRR. As usual with such hot and dry
conditions, the main concern with any storms will be strong gusty
winds. Cannot rule out wind gusts over 60 MPH with storms.
Models continue to remain in excellent agreement regarding hot
temperatures over the weekend. The next few days will be some of the
hottest of the season thus far, with many locations in the running
to break a few records. Over the next day or so, the upper-level
high over the Great Basin will gradually shift eastward, settling
over Colorado by Sunday. Compared to previous runs, both the GFS and
ECMWF have trended 700 mb temperatures down slightly. Ranging from
roughly +16C to +20C, temperatures will of course still be very hot,
with afternoon highs in the 90s to low 100s. Saturday potentially
could be the hottest day of the weekend, as models show the
warmest 700 mb air in place during this time. Less afternoon
cloud cover will also likely lead to warmer temperatures
Saturday afternoon. Heat Advisories remain in place for much of
southeast Wyoming and the Nebraska panhandle through the
weekend.
Aside from the heat, precipitation chances could be possible
Saturday and Sunday. Decreased PoPs Saturday afternoon as the
HRRR was not showing much in the way of convection across the
CWA. Model soundings from the GFS also paint a very dry picture
during the day Saturday. Very profound inverted-v profiles and
lack of any decent mid-level moisture could lead to the
development of high based clouds, but not much else.
Precipitation chances look a bit better later Sunday afternoon.
Increased mid-level moisture will lead to more cloud cover on
Sunday, with models showing increased chances for scattered
convection.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 216 PM MDT Fri Jul 12 2024
The upper-level ridge that has been impacting the region and
bringing in near-record high temperatures will begin to breakdown
starting Monday. An upper-level trough is progged to propagate
eastward along the United States/Canada border, forcing the ridge to
weaken an be pushed back to the west throughout the day. A 594dam
high will remain centered across the Four Corners region, ushering
in Monsoonal moisture around the high and into southeast Wyoming and
western Nebraska. As the ridge weakens and the high is pushed over
the Four Corners region, zonal flow will develop overhead with a
500mb shortwave pushing through. Atmospheric moisture will increase
significantly as upper-level southwesterlies and surface
southeasterlies bring in Monsoonal and Gulf moisture. PW values will
surge to over an inch for western Nebraska and most of southeast
Wyoming. A weak cold front associated with the upper-level trough
will slide across the region and interact with well above average PW
values and southeasterly flow, leading to the development of showers
and thunderstorms. With PW values well over an inch and weak
steering flow, heavy rainfall is possible on Monday with the passage
of the cold front. Some strong storms may be possible as modest
instability will exist across the region. This setup will need to
continued to monitored to assess the threat of severe weather for
Monday. Increased cloud cover is expected as well due to the
additional moisture across the region. High temperatures will be in
the mid-80s to mid-90s area wide.
Slightly cooler temperatures are forecast for Tuesday behind the
passing cold front on Monday. Highs are progged to be in the low-80s
to low-90s area wide. The upper-level ridge will attempt to
redevelop and restrengthen west of the CWA, but the 500mb high
remains in place across the Four Corners region and slightly wobbles
back to the west. The continued presence of the high over this
region will favor Monsoonal moisture being advected into the region
for another day. Similar to Monday, surface southeasterlies will
advect in additional Gulf moisture leading the PW values once again
above an inch for the Nebraska Panhandle and far southeast Wyoming.
A 700mb trough off to the northeast will lead to northwesterly flow
at this level and slightly cooler temperatures as cooler air moves
into the region. With a few passing 500mb vorticity maxima, showers
and thunderstorms are favored for Tuesday once again. Steering flow
will be weak again, leading to the potential for heavy rainfall
across the region for Tuesday. Severe weather may be more favored
for Tuesday as more MLCAPE will be available across the Nebraska
Panhandle. However, forcing across the region will be slightly
weaker as a very week cool front pushes through.
For the remaining long term forecast, the upper-level ridge will
continue to try to build across the western CONUS with primarily
northwesterly flow over the region Wednesday through the weekend.
The ridge is progged to strengthen and move easterly throughout the
latter half of the week. Therefore, a warm up is expected beginning
Thursday and continuing through the weekend. Next weekend does not
look as hot as what is currently ongoing across southeast Wyoming
and western Nebraska, but temperatures will be back into the 80s and
90s everywhere. With the ridge moving back overhead, precipitation
chances will begin to decrease for the latter half of the week. Some
daily chances for a shower or thunderstorm off the higher terrain
exist, but coverage will be much less than what is expected Monday
and Tuesday. Wednesday will be the coolest day of the week with
highs in the upper-70s to mid-80s area wide.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 938 PM MDT Fri Jul 12 2024
West northwest flow aloft will continue. Mostly clear skies will
prevail, with periods of scattered to broken clouds from
10000 to 12000 feet. Expect occasional thunderstorms at Chadron
until 08Z, producing wind gusts to 40 knots and ceilings near
8000 feet. Winds will gust to 23 knots at the Wyoming terminals
from 15Z to 00Z.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Heat Advisory from 10 AM Saturday to 8 AM MDT Monday for
WYZ101-102-107-108-118-119.
NE...Heat Advisory from 8 AM Saturday to 8 PM MDT Monday for NEZ002-
003-019>021-054-055-095-096.
&&
$$
SHORT TERM...SF
LONG TERM...AM
AVIATION...RUBIN
Area Forecast Discussion
National Weather Service Sioux Falls SD
1035 PM CDT Fri Jul 12 2024
.KEY MESSAGES...
- Wildfire smoke continues to stream overhead through the
weekend into early next week. Surface impacts are currently
not expected.
- Showers and thunderstorm chances are low tonight through the
weekend. However, if a storm is able to develop, strong to
severe storms may occur.
- Temperatures and dew points increase for the weekend. Heat
Advisory in effect for Saturday. Moderate (40%-60%) chance of
exceeding criteria Sunday.
- Unsettled pattern continues early next week, with periodic
shower and storm chances. Temperatures near climatological
averages.
&&
.DISCUSSION...
Issued at 239 PM CDT Fri Jul 12 2024
CURRENTS THROUGH TONIGHT: Additional diurnal cumulus clouds
have developed today, with hazy skies due to continued wildfire
smoke. We`ve climbed into the 80s and with dew points in the 60s
to lower 70s, heat indices are in the lower 90s for some folks.
Showers have been trying to develop but are struggling due to
the cap and lack of moisture. Winds increased through the early
afternoon with now southerly winds gusting to around 30 mph.
Gusts taper off after sunset, with southerly winds around 5-10
mph overnight. Although a couple of hi-res models hint at valley
fog developing, think winds remain just strong enough overnight
to preclude development. Lows tonight "drop" into the upper 60s
and lower 70s. Capping in place should keep us dry overnight,
but can`t entirely rule out a very isolated storm.
THIS WEEKEND: With the ridge in place over the southern US, our flow
pattern generally remains west-northwesterly through the weekend.
Not only does this allow the heat and humidity to build (more on
that in a minute), we`ll see hazy skies continue as wildfire smoke
streams eastward. The HRRR guidance brings in some periodic higher
concentrations through the weekend, but with the strong inversion
limiting mixing and low level southerly flow, impacts at the surface
are not expected.
Guidance has underdone dew points for today so with that in mind,
have continued to try to trend those values up. Combined with above
average temperatures (highs in the 90s), have issued a Heat Advisory
for the entire area for Saturday afternoon and evening with heat
index values near/above 100 degrees F. Models did come in cooler for
Sunday, but think this is due to the models struggling with
convection. Bumped up the NBM a couple of degrees closer to the
previous forecast using some of the NBM 75th; however, held off on a
headline for now to determine if the "cooler" temps are a trend in
the models or a fluke this run. Headline or now, hot and humid again
Sunday, with highs near/in the 90s. Lows through the weekend in the
upper 60s to lower 70s.
We`ll also be keeping an eye on convective chances through the
weekend with a few waves moving through (continued disagreement in
the models in timing/location). 925/850 mb temperatures both in the
20-30 degree C range leads to a stout capping inversion. Once again
this afternoon, CAMs continue to struggle with evolution and
development of convection through the weekend. Again, think that
capping will prevent most development in our area, and also cause
storms which advect into our area to struggle. However, robust
instability thanks to the heat and humidity, increasing shear, and
steep mid level lapse rates would all favor strong to severe storms
*if* a storm can develop. Ping pong ball sized hail, wind gusts to
70 mph, and locally heavy rain are the main hazards although again,
convective chances are very low.
Given the heat, humidity, and isolated storm risk, folks with
outdoor or travel plans should keep an eye on the forecast for the
latest information. Plan now for heat impacts and have a plan in
case storms develop.
MONDAY ONWARD: High pressure continues to spin over the southwestern
US through at least the middle of next week. Upper troughs and
stronger waves toward mid week bring a return to more northwesterly
flow aloft than the westerly flow we will see over the weekend. This
will likely keep periodic rain and storm chances around, but should
allow temperatures to moderate back to near climatological normals.
After Monday, highs return to the lower/mid 80s (possible as cool as
the mid 70s for some) and lows fall into the 50s and 60s.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1034 PM CDT Fri Jul 12 2024
Showers and thunderstorms remain across portions of North Dakota and
western South Dakota this evening. Think any storm that progresses
east/southeast will encounter more stable air and thus diminish. It
is possible that some weaker showers could last into KHON but
confidence is too low to include in KHON`s TAF as of now. Also think
tomorrow will continue to be dry given continued capping but will
monitor trends. Light southeasterly winds are expected to persist
through the night before turning southerly by tomorrow afternoon.
The southerly winds will finish out the TAF period.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory from 1 PM to 8 PM CDT Saturday for SDZ038>040-
050-052>071.
MN...Heat Advisory from 1 PM to 8 PM CDT Saturday for MNZ071-072-
080-081-089-090-097-098.
IA...Heat Advisory from 1 PM to 8 PM CDT Saturday for IAZ001>003-
012>014-020>022-031-032.
NE...Heat Advisory from 1 PM to 8 PM CDT Saturday for NEZ013-014.
&&
$$
DISCUSSION...SG
AVIATION...Meyers
Area Forecast Discussion...CORRECTED
National Weather Service Hastings NE
903 PM CDT Fri Jul 12 2024
...Key Messages and Short Term Update...
.KEY MESSAGES...
- Spotty thunderstorm chances (15-20%) late tonight into early
Sat AM, but severe threat looks low (SPC has recently removed
a formal Marginal Risk from our coverage area)
- Dangerous heat expected this weekend, with a Heat Advisory in
effect from 1pm Saturday through 8pm Sunday.
- Widespread heat index values of 100-110 degrees on Saturday
and Sunday. Heat index values over 100 possible across
portions of the area on Monday.
- Cooler temperatures and precipitation chances (15-55%) return
by the middle of next week.
&&
.UPDATE...
Issued at 830 PM CDT Fri Jul 12 2024
-- Some fresh thoughts regarding thunderstorm/fog potential
overnight (and summary of forecast updates made since main
"afternoon package" was issued earlier this afternoon):
- Thunderstorm potential:
Not surprisingly, SPC has recently removed their Marginal Risk
of severe storms from our entire coverage area (CWA) for the
rest of tonight on their latest update. Here at the local level,
we fully support this, as although there are a few stronger
storms ongoing well to our northwest in NW Neb at this time
(with more probably developing into that area yet this evening),
the vast majority of this activity is expected to focus at least
slightly off to our west as it rides south- southeastward into
early Sat AM. In addition, with warmer air aloft directly
overhead versus last night (700 millibar temps 12-14C), capping
overnight will be quite strong to any lower- level parcels. That
being said, latest RAP suggests that especially western parts of
our CWA could realize modest available elevated instability of
500+ J/kg late tonight into Sat AM (rooted mainly up around 700
millibars/10K ft. AGL), which could MAYBE support a few sneaky
stronger storms especially well after midnight to around 8-9 AM
Saturday (main hazards gusty winds to around 50 MPH and possible
weak heat bursts...lesser threat of smaller hail).
As a result of above reasoning:
Have "reworked" our overnight forecast a bit to remove all pre-
midnight thunderstorm chances, while expanding post-midnight
slight chances (20%) to include the majority of our CWA (except
a few far northeast/east-central counties which appear least
favored). For now, have not extended any formal thunderstorm
chance beyond 7 AM, and will defer to overnight shift to decide
if it`s warranted.
- Fog potential:
Much as was the case yesterday evening (for Friday AM), we are
not expecting any kind of widespread and/or dense fog situation
overnight into Sat AM, and most models/guidance indicate only
weak signals for even light fog. That being said, the very high
dewpoints/humidity levels are hard to ignore, with even late-
night dewpoints expected to drop no lower than mid-upper 60s
especially in north-northeast portions of our CWA. While winds
will not be truly calm (should be 5+ MPH most places, and there
could be some passing mid-high level clouds (both mitigating
factors to a more widespread/dense fog situation), the
aforementioned copious low level moisture, along with signals
of a weak warm front setting up late tonight near I-80, suggest
that counties especially along/north of I-80 are most favored to
see at least patchy light fog development (if not more "areas"
in nature especially in favored low-lying and valley areas, near
rivers etc.).
As a result of above reasoning:
Have at least introduced basic "patchy fog" potential to several
counties mainly along/north of I-80 mainly for the 3-9 AM time
frame. This also aligns well with latest 21Z SREF visibility
progs, which also highlights our northern counties for the
overall-highest (20-40%) chances for visibility dropping to 1 mile
or less a few hours either side of sunrise.
&&
.DISCUSSION...
Issued at 308 PM CDT Fri Jul 12 2024
This Afternoon and Overnight...
Highs this afternoon have climbed into the upper 80s to upper 90s
with heat index values in the mid to upper 90s. Portions of north
central Kansas will have heat index values top out around 100
degrees.
Thunderstorms are expected to develop over western Nebraska this
afternoon and move east into the area during the evening-overnight
hours. Overall thunderstorm coverage is expected to be fairly
isolated, with most HREF members showing only isolated coverage.
Thunderstorms will weaken as they move east with a loss of daytime
heating and increasing capping. Instability and shear will be
sufficient for a few strong to severe thunderstorms, capable of
producing damaging wind gusts and large hail. Scattered showers and
thunderstorms chances shift east overnight, ending by sunrise on
Saturday.
Saturday through Monday...
The biggest concern for the forecast period is the potentially
dangerous heat this weekend. A Heat Advisory has been issued for the
entire forecast area from 1pm Saturday through 8pm Sunday.
Temperatures will increase across the area on Saturday, with highs
in the mid 90s (north) to mid 100s (south). Heat index values of 100-
105 degrees are expected across most of the area on Saturday. Lows
Saturday night are expected to remain in the 70s for most areas,
providing limited relief from heat overnight. The hottest day of the
forecast period will be on Sunday, as highs soar into the upper 90s
(north) to mid 100s (south-southwest). Heat index values of 105 to
110 degrees are expected across the area.
An approaching trough will bring a cold front into the area on
Monday. The exact timing of this front is still uncertain, however
areas behind the cold front will see cooler temperatures with highs
in the low 90s. Areas that remain south of the front through the
late afternoon hours will see another day with highs in the upper
90s to mid 100s and heat index values over 100 degrees. Areas north
of I-80 are the most likely areas to see the cold front pass through
by the mid afternoon hours. Areas along and south of the NE/KS
border are the most likely to not see the cold frontal passage until
the evening hours. Heat headlines will likely be needed for portions
of the area on Monday, though it will depend on the timing of the
front. Mostly dry weather is expected this weekend, though an
isolated thunderstorm may impact northern portions of the area
Sunday night.
Overall, potentially dangerous heat is expected across the area this
weekend and into Monday. Heat index values over 100 degrees are
expected across the area on Saturday and Sunday, and a portion of
the area on Monday. Those with outdoor activities this weekend will
want to take precautions to avoid heat related illnesses.
Monday night onwards...
Thunderstorm chances (15-30%) return to the area Monday evening-
overnight. Cooler temperatures are expected on Tuesday, with highs
in the 80s across north central Nebraska and in the low 90s across
north central Kansas.
A welcome break from the heat will arrive by the middle of the week.
Highs in the upper 70s to low 80s are expected across the area on
Wednesday and Thursday. Scattered precipitation chances (15-55%)
continue across the area Tuesday through Thursday, with the highest
chances (35-55%) occurring Tuesday night.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 722 PM CDT Fri Jul 12 2024
For KGRI/KEAR Airports:
- General overview:
Unless some "sneaky" sub-VFR visibility and/or ceiling manages
to develop late overnight in light fog, confidence is high in
VFR conditions throughout. There is also an outside chance for a
passing, high-based shower/weak thunderstorm at some point late
overnight into early Sat morning, but this is deemed a low
probability (only 10-20%). Winds should not be a significant
issue throughout, with sustained speeds mainly at-or-below 10KT
and direction mainly somewhere between east-southeasterly and
southerly.
- Ceiling/visibility/precipitation/thunderstorm details:
Starting with light fog potential:
While nearly all models/guidance are currently very pessimistic
that much of any fog will develop overnight (possibly slightly
more favored 25+ miles north of KGRI/KEAR), am a bit concerned
that some "sneaky" sub-VFR visibility could indeed materialize
given such high humidity levels in the presence of light south-
southeast breezes. As a result, will at least "hint" at this
potential with a low-end VFR "6SM BR" focused 09-13Z. Outside of
any light fog potential, however, confidence is high in VFR
with only varying degrees of passing mid-high level clouds.
As for rain/thunderstorm potential:
A few higher-res models suggest that especially the 09-13Z time
frame could also bring the potential for a few very spotty,
high-based showers or non-severe storms. However, with this
chance deemed no higher than 10-20% have omitted from TAF
inclusion.
- Winds (including weak LLWS potential):
No significant issues foreseen here, as sustained speeds
through the period should average near-to-below 10KT, although
direction will fluctuate somewhat between east-southeasterly
(mainly overnight) and more southerly (mainly Saturday daytime).
Regarding weak low level wind shear (LLWS) potential:
It appears some fairly weak LLWS could occur tonight mainly
06-10Z as winds within the lowest 1,500 ft. AGL increase to
around 30KT out of the south-southwest. However, with shear
magnitude between the surface and this level currently expected
to top out closer to 25KT than 30+KT, have opted against formal
TAF inclusion.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory from 1 PM Saturday to 8 PM CDT Sunday for
NEZ039>041-046>049-060>064-072>077-082>087.
KS...Heat Advisory from 1 PM Saturday to 8 PM CDT Sunday for
KSZ005>007-017>019.
&&
$$
UPDATE...Pfannkuch
DISCUSSION...Davis
AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Grand Junction CO
529 PM MDT Fri Jul 12 2024
.KEY MESSAGES...
- Near-record daytime temperatures are expected today and
Saturday especially in the lower valleys.
- Afternoon showers and thunderstorms will develop over higher
terrain each day throughout the seven-day forecast with an
increase in coverage expected early next week.
- Temperatures remain elevated beyond the weekend, but some
relief is expected from cloud cover and shower activity as
monsoonal moisture is forecast to return early next week.
&&
.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 314 PM MDT Fri Jul 12 2024
High pressure continues to sit to our west, directing a
northerly flow across the area. This is allowing the heat dome
to persist, with warm air advection to continue through the
weekend as the high pressure shifts directly overhead by
Saturday. Near record high temperatures are possible across the
area with triple digit heat across eastern Utah and west-central
Colorado valleys, in fact we are already there this afternoon.
The Heat Advisory remains in effect through Saturday and made
no changes to the coverage area or timing due to the
uncertainty of sub-tropical moisture return on Sunday and what
kind of impact increased clouds and storm activity will have on
the high temperatures for Sunday. This is something for later
shifts to re-evaluate. In this heat, make sure to limit your
exposure and stay hydrated.
Storms continued to develop again across the southern mountains
like yesterday, except a little bit further west across the
Abajos and La Sals. The HRRR seemed to have a better handle on
the timing and coverage of storms so nudged the PoP fields
towards the HRRR as well as hi-res WRF to better reflect these
trends in the forecast. Storms were hot to begin with on radar
but have since cooled down, but gusty outflow winds of 40 to 50
mph and lightning appear to be the primary concerns. The air
mass is very dry as evidenced by our 12Z GJT inverted V sounding
and relative humidity in the single digits to teens in the
lower valleys. These storms also have a tendency to drift into
the adjacent southern valleys but are collapsing as they do, so
again, gusty outflow winds will be common. Storms appear to be
driven by daytime heating, steep lapse rates upwards of 9C/km,
quite a bit of DCAPE and a little bit of shear, so small hail
is also possible. Storm activity should die down by sunset with
a similar story expected for Saturday with highs a bit hotter
than today and similar storm coverage over the high terrain with
high pressure directly overhead.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 314 PM MDT Fri Jul 12 2024
By Sunday the high pressure that has been bringing all the heat
will be centered roughly over the Four Corners. This means
Sunday is likely to be yet another scorcher, especially for the
desert valleys where highs in the low 100s are once again
forecast. That said, by Sunday we are also expected to tap into
a plume of monsoonal moisture rotating around the high, with
PWATs forecast to climb to 100-150% of normal. This will lead to
increased storm coverage over the higher terrain, and an
increase of clouds overall, which may put a slight damper on
temperatures, but only by a few degrees compared to the days
previous. In addition, the prolonged period of hot and dry
weather prior to this monsoonal push means surface levels will
be extremely dry and will take some time to moisten. Therefore,
the main threats with any storms will be gusty outflow winds and
lightning, with the potential for some small hail or a very
brief downpour. A trough dropping through the Northern Plains
Monday into Tuesday will nudge the high back westward somewhat,
cutting us off from the moisture plume once more. The moisture
that did advect in on Sunday and Monday will stick around for a
bit, being recycled each afternoon and leading to daily showers
and thunderstorms favoring the terrain. This increased storm
coverage should continue to nudge temperatures down a few
degrees through the week. Highs on Sunday and Monday will run
around 10 degrees above normal, dropping to around 5 degrees
above normal by mid to late week.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 529 PM MDT Fri Jul 12 2024
Radar trends have been decreasing over the 4 Corners area after
some stronger storms dropping some decent rainfall and gusty
winds. Higher based virga or isolated showers are dropping
through northern portions of Utah and Colorado which could push
out some stronger winds through sunset. Otherwise VFR and light
winds can be expected overnight with another round of showers
and storms forming again in the heat of the day on Saturday.
Gusty winds remain the main threat to aviation interests.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Heat Advisory until 9 PM MDT Saturday for COZ006.
UT...Heat Advisory until 9 PM MDT Saturday for UTZ024-027-029.
&&
$$
SHORT TERM...MDA
LONG TERM...BGB
AVIATION...TGJT
Area Forecast Discussion
National Weather Service Green Bay WI
1039 PM CDT Fri Jul 12 2024
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- Isolated showers/storms will be possible through this evening.
While severe weather is not expected, any storms could produce
locally heavy downpours.
- A few rounds of strong to severe storms are possible from
Saturday through Monday. The mostly likely times are Saturday
night, and again Monday afternoon/evening. However, there is
still high uncertainty.
- Warmer and more humid conditions arrive Saturday through Monday.
Heat index values in the 90s are expected over central, east
central and parts of far northeast WI Sunday into Monday.
&&
.DISCUSSION...
Issued at 401 PM CDT Fri Jul 12 2024
Short Term...Tonight and Saturday
Main forecast concerns for the short-term will revolve around
severe weather potential and building heat and humidity. Best
timing for anything severe looks to be late Saturday evening and
into the overnight, although CAMs are currently showing a variety
of different scenarios that could play out.
Showers/storm potential this afternoon/evening... Mid-level
capping and dry air intrusion from high pressure situated over
Michigan`s lower peninsula have kept shower activity at bay
through the early afternoon. However, decent moisture and
instability (~2,000 J/kg CAPE) have sustained a mid-level cu field
across the entirety of the CWA. Some pulse showers/storms may be
possible into this evening, although dynamics don`t look too
impressive given the absence of any surface features or triggers
to focus convection. This being said, anything that does go up may
have the potential to produce brief heavy downpours given PWATs of
1.25" and weak storm motion.
Fog/smoke... Some patchy ground fog will be possible tomorrow
morning, especially in areas if/where any rain falls today.
Some elevated Canadian wildfire smoke was also observed across
the upper Midwest, enough to create hazy conditions. While areas
of thicker smoke will remain off to our northeast, even a thin
layer of smoke may be enough of a hindrance to prevent us from
reaching convective temperatures later this afternoon and evening.
Saturday severe weather potential... Most likely solution currently
shows a complex of storms coming down from the northwest late
Saturday evening into early Sunday morning, mainly before 12Z.
Main source of discrepancy between CAM guidance centers around
shower/storm activity earlier in the day as weak shortwave energy
treks across the Great Lakes. The HRRR solution favors convection
developing off to our west along the axis of greatest instability
Saturday afternoon before dissipating as it encounters drier air
over central Wisconsin. Other short-range models show more
isolated/pop-up activity during peak heating. There are some
questions as to whether or not this will hinder the
east/southeast progression of the MCS later in the evening, with
the most recent suite of CAM guidance favoring a slightly later
arrival than was shown this morning. Current thinking is that any
organized storms would be hard to come by earlier in the day due
to the influence of dry air from departing high pressure and low-
level capping. Inverted-V soundings indicate locally damaging
winds as the primary severe threat for Saturday evening, while
mid-level lapse rates and wet bulb zero heights favor hail as a
secondary threat.
Otherwise, persistent southerly flow looks to make this weekend
rather unpleasant as temperatures climb into the low 90s and a
surge of low-level moisture brings dewpoints up into the low 70s.
The combination of heat and humidity will result in heat indices
potentially reaching the mid 90s tomorrow, and flirting with heat
advisory criteria on Sunday. A persistent southeast lake breeze
will keep temperatures along the lakeshore slightly cooler.
Long Term...Saturday Night Through Friday
The focus is on the first 48 hours or so of the long-term
forecast with the potential for multiple rounds of convection.
Heat and humidity will also be a concern during this time.
Saturday night...Already starting out with high uncertainty at
00Z/Sun. Some indication thunderstorms or a convective system
could be moving across the area at this time, or it could have
dissipated already (as discussed above). Regardless, attention
will quickly turn to a compact shortwave coming through Saturday
night. This is more likely to generate a thunderstorm complex
across northern Minnesota Saturday evening, which tracks into
Wisconsin overnight (timing window anywhere from 9PM to 6PM across
the forecast area). Placement is uncertain, but generally favors
a southeast movement across most of the forecast area. Damaging
winds would be the main threat, with smaller potential for large
hail and localized heavy rain/flooding.
Sunday...A morning break from convection, however the heat and
humidity build during this time. Dew points rise into the lower
70s for most of central and east-central WI (in the mid-60s across
north- central WI). High temps forecast in the mid 80s to low 90s
will yield heat index values as high as 95 to 100 across central
and east-central WI. However, temps could be impacted slightly by
any lingering clouds or smoke aloft, along with any isolated
thunderstorms. While most models favor a cap holding off any
thunderstorms, and there is limited upper level dynamics, will
want to watch for any meso scale interactions which could lead to
some isolated thunderstorm potential. A lot of CAPE will be in
place, so anything which does develop could become severe.
Monday...Once again looking at significant moisture with dew
points in the low 70s, and afternoon highs in the low 80s, and
increasing instability. There are more dynamics at play, leading
to somewhat higher confidence for thunderstorms. A surface cold
front, along with mid-level shortwave, and RRQ of upper jet will
all serve as larger scale lifting mechanisms. Timing and details
are less certain given the prior activity.
Tuesday through Friday...Quieter and more seasonable temperatures
settle into the region.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1039 PM CDT Fri Jul 12 2024
VFR conditions are expected tonight and Saturday. Satellite
imagery indicates some Canadian wildfire smoke is aloft, which may
cause some hazy conditions at times. Surface winds are expected
to be light through the TAF period. Thunderstorms are possible
Saturday afternoon and evening as a thunderstorm complex develops
across Minnesota and tracks east through the region. CAMs models
are in poor agreement regarding exact timing of this complex;
however, there appears to be enough of a chance (30 percent)
across central and north-central Wisconsin to include a PROB30
group in this set of TAFs for AUW/CWA/RHI. Further east confidence
is too low to include at this time. Any thunderstorms would likely
reduce conditions to MVFR or IFR at times.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Goodin/KLJ
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
931 PM EDT Fri Jul 12 2024
.SYNOPSIS...
Drier conditions return this weekend, lingering into early next week
as high pressure builds across the area. This will allow hot weather
to return with afternoon highs climbing into the upper 90s and lower
100s east of the mountains. A pattern change is expected mid-week
into next weekend as a cold front stalls across the area and brings
above normal rain chances and cooler weather.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 930 PM EDT Friday: Isolated showers developed over the
southern NC Foothills and central NC mountains along the Blue Ridge
Escarpment within the last hour and a half thanks to ENE`ly flow.
These showers are starting to lose steam and are trying to fall
apart as they slowly sink southward. With convection remaining
mostly stationary, the main concern with any lingering cells
continues to be heavy rainfall. Once winds toggle more north the
next few hours, convection development should end. Seeing cloud
cover bank up along the Blue Ridge Escapement tonight thanks to the
ENE`ly flow as well so increased cloud cover across these locations.
Lows tonight will end up around 3-5 degrees above climo.
Otherwise, a surface boundary stretched across the Coastal Plain of
the Carolinas will have a weak surface low ride along the boundary
will slowly lifting north through the period. Most of the area will
be on the subsident side of the low and thus, limiting shower and
thunderstorm potential west of the boundary. The surface wave will
lift northeast of the CWA overnight as the mid/upper-level low gets
absorbed by the upper troughiness over the northeastern CONUS.
Summertime regime will be in store for Saturday as weak high
pressure sets up over the CWA, while the Bermuda High re-establishes
its position over the western Atlantic and slowly turns surface
winds back out of the south-southwest by the end of the forecast
period. With 594-596 dm thicknesses in place, and dewpoints ranging
from the upper 60s to lower 70s, expect a few locations south and
east of I-85 to see heat indices climb into the low 100s. Highs
should end up around 3-5 degrees above climo. CAMs are not in good
agreement regarding the overall coverage of showers and
thunderstorms Saturday afternoon/early evening. Both the HRRR and
NAMNest show convection first developing over the mountains by
Saturday afternoon before pushing east the rest of the day. However,
the NAMNest depicts a broken line of isolated convection while the
HRRR depict widely scattered convection. Thus, capped PoPs to slight
chance (25% or less) area-wide for now.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 224 PM Friday: Broad upper troughing will be draped from the
Northern Plains across the Great Lakes and into New England. Farther
west, a stout 600dam upper ridge will be parked over the Four
Corners region with broad ridging extending across the Southern
Plains and into the Lower Mississippi Valley. Ridging is forecast to
build east through the later half of the weekend and into the start
of the new week with heights rising across the Southern Appalachians
along with an uptick in low-level temperatures. This will support
rather hot temperatures with afternoon highs climbing into the low
to upper 90s on Sunday and mid 90s to low 100s on Monday. Any good
news, though, is that the frontal boundary that has been waffling
across the I-77 corridor is forecast to shift back east as flow
shifts to out of the west/northwest. This will shunt higher
dewpoints and richer moisture into the Coastal Plain with dewpoints
able to mix out more efficiently each afternoon. This will in turn
help keep heat indices in check with low 100s along and south of I-
85 on Sunday. While dewpoints will remain relatively low on Monday,
temperatures in the upper 90s to low 100s will be hot enough that
even lower end dewpoints could end up supporting heat indices near
advisory criteria (105 degrees) and a heat advisory may ultimately
be needed. Subsidence from the upper ridge and a lack of deeper
moisture will preclude diurnal convection across much of the area,
but an isolated shower and/or thunderstorm cannot be completely
ruled out across the mountains.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 232 PM Friday: The blowtorch will continue as we head into mid
week, especially on Tuesday, as the 850mb temperatures peak near 24
C. This will support at least one more day of hot weather with
afternoon highs once again peaking in the mid 90s to low 100s. A
potent upper trough is also progged to swing across the Northern
Plains and into the Great Lakes on Tuesday with an attendant surface
cold front dropping across the Midwest. Surface high pressure will
have also shifted offshore with low-level flow backing to out of the
south. This will allow for gradual moisture return into the area off
the Gulf of Mexico and eventually the Atlantic Ocean. PoPs slowly
return on Tuesday, but most of this activity may remain just south
of the area within the initial moisture return across the Deep South
into Georgia. A noticeable pattern change is still on tap for
Wednesday into next weekend as the upstream frontal boundary
approaches and then eventually stalls across the area as the upper
trough lifts across the Ohio Valley into New England. Lingering low-
level warmth may result in one last day of heat concerns on
Wednesday, but this will be conditional with PoPs quickly ramping
back up within the leading edge of moisture return. A more robust
afternoon cumulus field and an early start to diurnal pulse
convection may limit heating and preclude the need for heat
products, but this will have to be assessed closer to the day. By
Thursday into next weekend, guidance continues to depict the frontal
boundary stalling either across or near the forecast area as the
front becomes oriented parallel to upper westerlies with the parent
trough lifting out of New England. This will result in above average
PoPs each day in the likely to categorical range, which will
hopefully bring much needed rainfall and cooler temperatures to the
area.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Have some scattered SHRA lingering across
western NC as of 01Z but this activity should dissipate in the next
hour or so. Removed VCSH at KHKY as -RA has dissipated around the
terminal. Did add a TEMPO at KAVL as an isolated shower (which is
also leading to low-end wind gusts) developed right over the
terminal. Otherwise, VFR should prevail at most locations through
the TAF period (outside of convection), with the exception of both
KCLT and KHKY. Both of these terminals have the potential to see
lowering CIGS and VSBYS overnight thanks to lingering low-level
moisture. KCLT is already starting to see an MVFR CIG develop as of
01Z. The NBM has backed off on cloud coverage overnight and shows
only FEW to SCT clouds through daybreak Saturday. This lines up well
with the HRRR but both the NAM and CONSShort are forecasting BKN to
OVC cloud cover. Thus, trended down cloud cover slightly compared to
the previous TAF update. Maintained an MVFR CIG at KCLT from 09Z-15Z
(BKN012) but also mentioned SCT005. For KHKY just went SCT023 from
09Z-13Z. Went ahead and maintained the MVFR fog mention at both KCLT
and KHKY based on the latest model VSBY guidance. Drier conditions
can be expected tonight into Saturday morning, but isolated
SHRA/TSRA may develop Saturday afternoon and evening. However, the
latest high-res model guidance is not in great agreement regarding
the overall coverage of diurnal SHRA/TSRA. Thus, went with dry
conditions across the terminals for Saturday with confidence too low
on whether convection will track directly over a terminal. Winds
will gradually decrease in speed through this evening, remaining NE
east of the mountains. Winds east of the mountains will then turn
more N/NW overnight into Saturday morning. Winds east of the
mountains will then gradually turn WSW/SW Saturday afternoon. Wind
speeds will be lighter on Saturday compared to today. A VFR cumulus
field will develop on Saturday afternoon/early evening.
Outlook: Isolated showers and thunderstorms are expected mainly over
the mountains Sunday into early next week. A cold front will
approach out of the northwest middle of next week before tracking
into the western Carolinas late next week. This will increase shower
and thunderstorm chances across all of the terminals. Morning
fog/low stratus will be possible each morning, especially across the
mountain valleys and for areas that received heavy rainfall the day
prior.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...AR/TW
NEAR TERM...AR/CAC
SHORT TERM...TW
LONG TERM...TW
AVIATION...AR
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
953 PM EDT Fri Jul 12 2024
.KEY MESSAGES...
- Hotter conditions make a comeback as we move into the weekend
and for next week.
- The next significant chance of rain will hold off until the
middle of next week.
&&
.UPDATE...
Issued at 953 PM EDT FRI JUL 12 2024
We have had some persistent showers and occasional thunderstorms
that have been forming along and ahead of an eastward advancing
outflow boundary. Given this updated to keep PoPs going for a
small portion of the areas mainly along and north of the Mountain
Parkway this evening. Some of these showers are producing brief
heavy rainfall of three quarters of an inch to one inch an hour
rates at times. Other than the PoPs no bigger changes are needed
for this update.
UPDATE Issued at 713 PM EDT FRI JUL 12 2024
We have had a few more showers that have develop further east
than expected. This could perhaps be an additional outflow
boundary that was undiagnosed. Either way opted to add in 15 or
less PoP in areawide for a few hours this evening. Outside this
only minor update to add in the latest obs and trends.
UPDATE Issued at 551 PM EDT FRI JUL 12 2024
A weak wave is noted in the mid-levels toward SE Missouri. This
has helped sparked off showers and a few thunderstorms across
western and central parts of Kentucky this afternoon. An outflow
off these storms is noted on satellite and WSR-88D data this
afternoon tracking slowly east toward parts of eastern Kentucky.
This has been aiding is developing a few showers and
thunderstorms at times as it tracks east. Given this opted to
keep 15 or less PoP right along our CWA border through the late
afternoon hours. These are expected to relent through the evening,
but HRRR (which has been verifying the best lately) has this
going a little longer into the evening. This trend will be
monitored for future updates. Outside this is a fairly minor
update.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 312 PM EDT FRI JUL 12 2024
The 15Z surface analysis continues to show high pressure situated
over much of the eastern CONUS. A weak surface low remains present
over the Central Plains with a surface boundary extending into the
Ohio Valley. In eastern Kentucky, high pressure remains dominate
with mostly sunny skies. Radar has been a little active over the
last hour or so with pop-up showers developing along and southwest
of the Mountain Parkway. These showers pulse up quickly then
dissipate. Isolated showers will be possible over the next few hours
before diminishing after sunset.
Aloft, a trough continues to be situated over the Great Lakes. The
CWA is presently situated at the base of the trough as it continues
to pivot northeastward out of the area. This trough is helping
trigger the shower activity across the area today but as the trough
exits and daytime heating wanes, those showers will cease to exist.
For the overnight, mostly clear skies will exist and allow for
radiational cooling in the river valleys. Thus allowing for the
development of areas of valley fog through the early morning hours
of Saturday.
Saturday brings about another hot and humid day as surface high
pressure remains overhead. Aloft, west to northwesterly flow will
usher in a drier airmass thus limiting the potential for shower
activity but cannot rule out a stray shower Saturday afternoon.
Overnight Saturday brings around another mostly clear night with
areas of valley fog that`ll burn of early Sunday morning.
Overall, the period will be mostly dry aside from a few isolated
showers or storms with passing clouds. Highs are forecast to be in
the mid to upper-80s into the lower-90s today before climbing into
low to mid-90s for Saturday. Overnight lows will remain mild across
the area too, as lows tonight will drop into the mid to upper-60s
for tonight and again Saturday night.
.LONG TERM...(Sunday through Friday)
Issued at 432 PM EDT FRI JUL 12 2024
There is reasonable agreement among models up until about mid week.
We should reside near the southern edge of the westerlies aloft on
Sunday. Our surface air mass is expected to modify to dew points in
the 65-70 range by then, with strong sun pushing highs to about 90
or a little warmer. The resulting forecast soundings show ample
instability. The question is whether or not there will be any
feature on which convection can focus. Being at the southern edge of
the westerlies aloft could provide something (perhaps a MCS
remnant), and a 20% POP was used. After this, the faster flow aloft
retreats to our north and northeast, and with this a dry forecast
was used for Monday. However, heat will remain.
After this, a large scale upper trough will be dropping southeast
out of Canada toward the Great Lakes and Ohio Valley. It will result
in geopotential height falls over our region for Tuesday, and
increasing mid/upper level flow by Wednesday along with further
height falls. The trough will also support a cold front which is
expected to approach Tuesday night and reach KY on Wednesday. Low
level flow ahead of the front will bring higher dew points off the
gulf into our area. The approaching upper level trough and
increasing dew points may allow for a few showers/thunderstorms on
Tuesday and Tuesday night. However, the highest POP looks like
Wednesday as the front arrives, and likely category was used area
wide.
Model agreement drops off after this point with regard to frontal
progression. The 12Z run of the GFS takes the front far enough to
our south to allow for dry weather here on Thursday and Thursday
night. The ECMWF is slower, with precip lingering longer, especially
in our southeast counties. A model blend being used will take the
differences into account in its averaging.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 1905 PM EDT FRI JUL 12 2024
We are seeing VFR conditions prevail over the TAF sites to begin
the period. The guidance continues to be bold with the fog
development tonight at some of the TAF sites, but not sure how
extensive this will be given the previous nights have been lack
luster. We are see more low to mid-level clouds than we saw
yesterday which would lead to less fog concerns. The one issue
would be any showers that can develop this afternoon could cause
more localized issues outside of the typical river valley fog.
Given this will lean toward mainly MVFR fog at SME/LOZ/SYM late
tonight between 8Z and 10Z. This will lift around 13Z to 14Z
Saturday morning. Then we will see VFR conditions prevail through
the remainder of the TAF period. The winds will remain light and
variable through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...VORST
LONG TERM...HAL
AVIATION...DJ
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
557 PM CDT Fri Jul 12 2024
.KEY MESSAGES...
- Hot and humid this weekend with the potential for several
conditional chances for strong to severe thunderstorms
Saturday through Monday.
- Slight Risk (2 of 5) of Severe Weather Saturday. All hazards will
be possible if thunderstorms develop, best chance along and
north of I-94.
- Cooler, drier pattern after Monday.
&&
.DISCUSSION...
Issued at 222 PM CDT Fri Jul 12 2024
Rest of Today... Diurnal cumulus clouds this afternoon forming
below an upper level inversion. With this inversion in place
thunderstorm activity should be capped this afternoon and
evening. Continued southerly flow will advect warmer and more
moist air into the Upper Midwest tonight. Subtle curvature aloft
could produce enough lift for some thunderstorm late tonight.
Saturday... Continued from the Rest of Today discussion CAMs
continue to show a line of storms forming Saturday morning. The
best chances will be to north of I-94. But some solutions like
the 12Z HRRR and NAM Nest have taken this farther south.
Continued advection will bring us our hottest day of the year,
especially over western Minnesota where heat index values will
be over 100. Widespread heat index values above 90 expected and
over 95 in the Twin Cities metro. Little recovery from heat
stress expected overnight with lows only in the lower to mid
70s. This will be especially pronounced in the core Twin Cities
where the urban heat island will help keep overnight
temperatures elevated, which is why the Heat Advisory extends
overnight into Sunday. As mentioned in the previous discussion
the environment will be favorable for thunderstorms. Above
normal precipitable water will allow for high rain rates, but
flow should be fast enough to avoid much of a flooding risk. On
the severe side CAPE is very high with multiple CAM soundings
showing values in excess of 3000 J/kg and some as high as 5000
J/kg. The question is when CI will occur. Forcing suggests later
in the day and surface cooling could cause issues with surface
based convection. The timing in most CAMs also suggests more of
an evening timing after peak surface heating. The boundary layer
up into around 850 mb thanks to the WAA will take longer to
cool such that a cap could form. Shear is sufficient for strong
to severe storms. Mid level lapse rates will support upward
motion, but low level lapse rates will depend on the time of
day. As the surface cools it will make the low level lapse more
complicated. SPC continues to have a slight risk (2 of 5) with
all severe hazards possible. Summary of this day, hot and humid
with both early day and late day thunderstorm chances (better
severe chances with the late round).
Sunday... The heat will shift south and east on Sunday with
lower, but still hot temperatures over western Minnesota. With
temperatures remaining hot in the morning there will be little
recovery from heat stress. A shortwave on Sunday will give
another chance for thunderstorms and with the warmth still
around plenty of instability. This will be another day to watch
out for, but this forecast is dependent on how Saturday plays
out. This could be just as hot if not hotter than Saturday for
the Twin Cities depending on where and when storms occur. Also
how worked over the atmosphere gets on Saturday will be key for
storm chances on Sunday. Ensembles highlight variable storm chances
for Sunday and we might not have high confidence until Saturday
afternoon on which direction the forecast goes. Regardless it
will be a hot day with another chance for thunderstorms. It is
just how hot and will storms form that are the questions.
Monday... The peak of the heat will be past us on Monday, but it
will still be hot but likely sub-advisory heat. This looks to
be the best synoptic setup of the next three days based on the
jet streak and 500 mb shortwave. Just less instability and a
shear setup more dependent on speed shear. Once again this day
will be dependent on the weekend days before and how the
atmosphere evolves.
Tuesday through Thursday... On the back side of Monday`s wave
cooler and drier move into the Upper Midwest. Highs will be in
the mid 70s to lower 80s, which after a weekend of 90s will be
quite a cool down.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 557 PM CDT Fri Jul 12 2024
Light southerly winds and mostly clear skies for much of the
night. Low chance for TS is expected late tonight across western
MN, then expanding eastward Saturday morning. There remains low
confidence in the development of this TS, spatial extent, and
timing. Therefore, maintained the PROB30 for all TAF sites.
KMSP...No concerns tonight, then chance of TS late Saturday
morning into the early afternoon.
/OUTLOOK FOR KMSP/
SUN...VFR, chc -TSRA/MVFR. Wind S 5-10 kts.
MON...VFR, chc -TSRA/MVFR. Wind W 5-10 kts.
TUE...VFR, Wind NW 5-15 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Heat Advisory from 1 PM to 8 PM CDT Saturday for Brown-
Chippewa-Lac Qui Parle-Redwood-Renville-Stevens-Swift-
Watonwan-Yellow Medicine.
Heat Advisory from 2 PM Saturday to 8 PM CDT Sunday for Anoka-
Carver-Dakota-Hennepin-Ramsey-Scott-Washington.
WI...None.
&&
$$
DISCUSSION...NDC
AVIATION...Borghoff
Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
854 PM EDT Fri Jul 12 2024
...New UPDATE...
.UPDATE...
Issued at 832 PM EDT Fri Jul 12 2024
Did wind up having a few isolated showers develop over the terrain
of the plateau late this afternoon and early evening. Those are on
the decline now and do not expect any further development.
Wouldn`t be surprised to have a similar scenario tomorrow as well.
Upper heights will rise tomorrow, but there`s a subtle shortwave
moving into western Kentucky this evening that will continue to
shift eastward tonight and through the day tomorrow. That could
hamper the effects of rising heights enough for there to be
another instance of some isolated showers over the higher terrain
of the plateau and certainly the Appalachians. That said, steering
flow, albeit weak, would likely keep any mountain convection on
mainly the NC side of things so the plateau may have relatively
speaking better odds. In any case, not enough confidence in this
low-impact aspect of the forecast (nearly all areas will be dry)
to consider making edits at this time.
Also made some slight adjustments to temperatures and dewpoints
through roughly midnight to account for current trends. Blended in
some of the latest HRRR which is slightly slower to cool temps
off and bring dewpoints up. Nothing significant though, and the
forecast seems to be in good shape otherwise.
&&
.SHORT TERM...
(This evening through Saturday)
Issued at 329 PM EDT Fri Jul 12 2024
Key Messages:
1. The area is likely to stay dry with even hotter temperatures on
Saturday in the mid to upper 90s across most of the area.
This Evening/Tonight
Currently this afternoon, weak upper troughing is centered to our
west with surface high pressure. Model sources indicate lower than
average PWAT values for mid July, around or even below 1 inch. Weak
flow from the N to NE has been around 5 to 10 kts and will continue
overnight. PoPs are low, however some scattered showers are possible
in our northeastern counties, due to fairly subtle surface troughing
to our east. Patchy fog is certainly possible in the northeast, but
continued dry air will limit development. With how dry conditions
are today, many places will likely drop into the 60s by the morning.
Tomorrow
Hot and dry conditions will continue as 500mb heights rise to around
5,940m. Dew points and PWATs are slightly higher, but much of the
region can still expect below average moisture. Winds become
northwesterly Saturday afternoon and evening. Model agreement
indicates MLCAPE values slightly higher than today with most areas
around 500 J/kg. Orographic lift from northwesterly flow could bring
isolated convection along the mountains, but this potential is very
limited due to continued dry air and subsidence. 850mb temperatures
will rise beyond 20 Celsius, which suggests that many areas will
rise well into the 90s. However, heat index values shouldn`t be too
much higher because of drier air due to the deep mixing and
subsidence.
&&
.LONG TERM...
(Saturday night through next Friday)
Issued at 329 PM EDT Fri Jul 12 2024
Key Messages:
1. Warming trend continues this weekend into early next week, with
the potential for record breaking daily high temperatures for the
start of the work week.
2. Outside of an isolated high elevation shower/storm, mostly dry
conditions are expected through the middle of next week.
3. Chances of precipitation begin to increase by late next week as a
weakness in the ridge develops.
Discussion:
Ridging will continue to dominate our weather through the weekend
and middle part of next week. This will result in continued dry
weather, sunshine, and warm 850mb temperatures around 22 to 25 deg C
across the Southern Appalachians and Tennessee Valley. Based on
these warm boundary layer temperatures, most model and statistical
guidance is placing max temperatures in the upper 90s to lower 100s
across the region which would be near record max high temperatures.
A few isolated showers or thunderstorms may be able to develop
across the higher elevations due to the differential heating along
the high terrain, but probabilities are less than 20 percent. Lack
of deep moisture and continued ridging will limit instability for
convection. This hot and dry pattern will likely exacerbate drought
conditions over the coming week.
By late next week, a weakness in the ridge is expected to develop
across the Mississippi Valley with increased convective coverage.
The question is how much convection will make it into our area with
continued ridging across the Southeast limiting the eastern
progression of precipitation. There are signals that perhaps we get
some relief with precipitation in the week two period, as seen in
the latest CPC 6 to 14 day outlooks, but confidence is low. At this
point, chances for meaningful rainfall coverage and amounts is not
very high over the next 7 days.
Daily Record High Maximum Temperatures
Date Chattanooga Knoxville Tri-Cities Oak Ridge
07-12 104(1930) 104(1930) 93(1993) 100(1980)
07-13 105(1980) 100(1936) 96(1993) 100(1980)
07-14 103(1954) 101(1954) 98(1954) 101(1954)
07-15 103(1977) 98(1995) 96(1995) 100(1980)
07-16 105(1980) 100(1980) 100(1988) 103(1980)
07-17 103(1980) 101(1980) 94(1980) 103(1980)
&&
.AVIATION...
(00Z TAFS)
Issued at 756 PM EDT Fri Jul 12 2024
Light winds and FEW060-070 will prevail through the period at all
sites. Likely see an ISOLD SHRA or two over the terrain of the
mountains or plateau again tomorrow afternoon and evening, but
doubt they would influence any terminals so will leave all sites
dry.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 97 72 98 75 / 0 0 0 0
Knoxville McGhee Tyson Airport, TN 93 69 95 72 / 0 0 0 0
Oak Ridge, TN 95 69 95 71 / 0 0 0 0
Tri Cities Airport, TN 92 64 92 67 / 0 0 0 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...CD
LONG TERM....JB
AVIATION...CD
Area Forecast Discussion
National Weather Service Raleigh NC
730 PM EDT Fri Jul 12 2024
.SYNOPSIS...
Areas of low pressure will ripple along a quasi-stationary front
over the Piedmont through tonight. The front will weaken and
dissipate over the region this weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 730 PM Friday...
Latest radar scans showing a few MCVs moving over the area. The main
one could be seen across over the Northern Piedmont swirling over
Vance, Warren and Franklin counties. The bulk of the rain is over
the Coastal Plain and Northeastern Piedmont. While areas are
expected to briefly dry out, another round of showers and storms are
expected to develop later tonight. The heavy rain threat and
flooding threats will continue into the overnight hours. Thus, the
Flood Watch for most of NC will not be cancelled early. Latest model
guidance is showing the best chance for redevelopment anywhere along
and east of the US1 corridor. Lingering showers overnight should be
pushing near the coast by sunrise as dry air moves into the region.
Lows overnight will range from low to mid 70s.
As of 218 PM Friday...
* Flood Watch remains in effect for all but the far western Piedmont
counties until midnight tonight
* Potential exits for localized 4+ inches of rainfall over portions
of the Piedmont and Coastal Plain
Sfc analysis this afternoon shows the sfc boundary stretching from
the southern Piedmont northeast through the northern Coastal Plain.
This area continues to see the strongest convection and rain rates.
A MCV was observed spinning over the Sandhills/central Piedmont when
looping radar scans. This feature, along with the instability axis
east of the boundary will continue to shift northeast over time
through this evening.
Latest high-res ensemble guidance (HREF/REFS/WoFS) all suggest the
possibility of higher rainfall rates falling first over the
southern/central Piedmont the next few hours, before pivoting up
into the northern Coastal Plain later this evening. There is a
signal for localized amounts as high as 5 inches in these areas.
Given the high rain rates thus far, the continued highly anomalous
moisture flux, and some reports of flooding, will continue the Flood
Watch through midnight tonight.
The bulk of the rain will pull north overnight tonight, but latest
runs of the HRRR do maintain the potential for some linger
showers/storms over our central/northern Piedmont. Overall though,
most of the rain should be north of our area through sunrise
tomorrow.
Overnight lows will remain in the mid 70s with patchy fog possible.
&&
.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 218 PM Friday...
While the sfc/mid-level low will have pulled bulk of the
precipitation north of our area by 12Z Saturday, anomalous moisture
will linger especially along and east of US-1. As such, additional
showers and a few storms will likely develop Saturday afternoon
along the dissipating frontal boundary. Highest chances will focus
further east. Flash flooding potential should be limited Saturday,
but we are still outlooked in a Marginal ERO from WPC across eastern
areas. FFG should be a bit lower given the heavy rain on Friday, and
thus urban areas could be susceptible to flash flooding. Although,
overall coverage should be more limited compared to Friday.
Temperatures will rise back into the lower to mid 90s, peaking
across the far southwestern Piedmont. Dew points will likely max in
the 70s again Saturday afternoon (highest to the east). However,
some fleeting wnwly flow aloft may introduce a bit of mixing
(especially out west where it will be hottest). Thus, heat indices
should stay below advisory criteria.
Warm overnight lows in the lower to mid 70s is expected.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY...
As of 252 PM Friday...
...Dangerous Heat Returns Sunday Through the Middle Part of Next
Week...
...Pattern change with trough developing to our west (Ohio Valley
into the TN Valley) late week into next weekend brings threat of a
stalling front and heavy rain/cooling temperatures...
The main weather story will be the return of dangerous heat
beginning Sunday and peaking Monday and Tuesday. Heights continue to
rise Monday and Tuesday. The low level flow is forecast to be more
westerly. Heat Advisory criteria looks likely to be met in the
southern and eastern areas where index values should reach and
exceed 105 Sunday and Monday even with some mixing out of the dew
points in the afternoon, then possibly Excessive Heat Warning
criteria of 110 on Tuesday and Wednesday as the heat wave peaks.
Actual highs should reach the mid 90s to lower 100s Monday,
Tuesday, and possibly Wednesday. Lows in the mid 70s to lower 80s.
Both could challenge daily records.
There is only a small chance of PM storms Monday and Tuesday.
The chance of mainly afternoon and evening thunderstorms returns
Wednesday especially in the west. All areas have a good chance to
likely Thursday and Friday as a cold front will approach from the
NW. Highs will "cool" into the lower to mid 90s Thursday and 80s by
Friday.
A potential wet period with less heat late next week into the
weekend.
&&
.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
As of 705 PM Friday...
TAF period: While most terminals are reporting VFR conditions around
00Z, widespread ceiling restrictions will develop overnight. While
RWI has a narrow window for dropping to LIFR ceilings, there is high
confidence in all other terminals dropping to 500 ft ceilings or
lower. Coverage of showers and thunderstorms has dropped a little
bit more quickly than anticipated, and a VCSH/VCTS mention should be
enough at most sites. The low ceilings should begin to lift shortly
after sunrise Saturday, and all sites should return to VFR
conditions by Saturday afternoon. A chance of thunderstorms will
return to RDU/FAY/RWI Saturday afternoon.
Outlook: Morning low stratus and/or fog will be possible again Sun
morning mainly at RWI and FAY, followed by primarily hotter and
mainly dry, VFR conditions until the next front settles into the
region late Wed through Thu.
&&
.CLIMATE...
Record High Temperatures:
July 15:
KGSO: 97/1974
KRDU: 99/1997
July 16:
KGSO: 99/1915
KRDU: 101/1887
KFAY: 103/1937
Record High Minimum Temperatures:
July 12:
KGSO: 76/2011
KRDU: 78/2011
KFAY: 80/1935
July 13:
KGSO: 75/2017
KRDU: 78/2017
KFAY: 78/2017
July 14:
KGSO: 77/1981
KRDU: 77/2017
KFAY: 80/2017
July 15:
KGSO: 74/2019
KRDU: 76/1992
KFAY: 78/2015
July 16:
KGSO: 75/2010
KRDU: 77/2010
KFAY: 78/1992
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
Flood Watch from midnight EDT tonight through Friday evening for
NCZ007>011-022>028-039>043-074>078-083>086-088-089.
&&
$$
SYNOPSIS...MWS
NEAR TERM...CA/Luchetti
SHORT TERM...Luchetti
LONG TERM...Badgett
AVIATION...Green/MWS
CLIMATE...RAH
Area Forecast Discussion
National Weather Service Sacramento CA
202 PM PDT Fri Jul 12 2024
.SYNOPSIS...
Hot and dry weather will continue through Saturday with Moderate
to Extreme HeatRisk persisting across much of the region. Elevated
fire weather conditions will also continue. Isolated thunderstorm
chances today-Sunday, mainly along the Sierra crest, best chances
from US-50 southward. Cooler temperatures on Sunday and into next
week.
&&
Key Points
- Long-duration, dangerous heat event persists through Saturday,
followed by some cooling over the weekend into next week.
- Chances of showers/isolated T-storms along the Sierra Crest
today through the weekend.
- Red Flag Warning has been issued for Fire Zones 221 and 269 for
elevations greater than 6000 feet.
.Discussion...
Another hot day in store for interior NorCal today. At the time
of this writing, it is 106 F at our Downtown Sacramento weather
observation site, and the temperature is forecast to climb to
around 110 as we move into the peak heating hours. Tomorrow we
expect a slight cooldown across the central Sacramento Valley,
Delta, and northern San Joaquin Valley with highs in the 90s to
105, with the coolest temperatures in the Delta thanks to onshore
flow. The Heat Advisory for the Delta and Sierra, as well as the
Excessive Heat Warnings for the Valley and Foothills remain in
effect until 9PM PDT tomorrow night.
We are still under the influence of a broad area of high pressure
in the Four Corners region and will remain affected by the high
pressure until at least Sunday night. Monsoonal moisture is
embedded within the high pressure, and is beginning to move into
our area this afternoon. Some flashes of lightning have been
observed this afternoon, mainly in far southeastern Tuolumne
County just east of Hetch Hetchy. This activity is moving off to
the northeast and out of our coverage area, however an isolated
shower or thunderstorm cannot be ruled out the remainder of the
day in the far southeastern sections of the forecast area.
Tomorrow, temperatures will cool as monsoonal moisture will
advect into interior NorCal, bringing some high clouds and
possible sprinkles across the Valley. Some Hi-Res Convective
Allowing Models (CAMS) such as the NAM and HRRR reveal the
potential for thunderstorms across the Sierra crest, with the best
chances south of HWY-50 tomorrow and Sunday. Forecast soundings
suggest a north-northeast steering current, so any storms that
develop could drift along the Sierra crest. Current National Blend
of Models probabilities for thunderstorms are around a 15-30%
chance for tomorrow and Sunday. With the elevated ERC values in
the Sierra and the potential for dry thunderstorms, a Red Flag
Warning has been issued for Fire Zones 221 and 269 for elevations
above 6000 feet beginning tomorrow at 5AM PDT and lasting through
Sunday at 8PM PDT.
Weak off-shore troughing develops Sunday as well and will promote
more onshore flow into the Delta and central Sacramento Valley,
which will help lower temperatures across the region. Confidence
has increased in relatively cooler temperatures as we move into
the next work week, with the return to near-normal highs. Moderate
HeatRisk will persist across the region beginning Sunday. Upper
level heights will remain in a westerly flow pattern, so the
relative cool down is expected to persist as we move into the
extended period.
Latest HeatRisk: wpc.ncep.noaa.gov/heatrisk/
Heat Safety Tips: weather.gov/safety/heat
&&
.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...
Tuesday and Wednesday, we will still have westerly flow aloft
which will promote more onshore flow and help us remain near
normal temperature wise. Widespread Minor and isolated Moderate
HeatRisk return, which will be a welcome relief after our record-
setting heat wave. Forecast high temperatures are currently
90-100, with the warmest temperatures in the northern Sacramento
Valley. Thursday and Friday, a ridge of high pressure will once
again try to build in over the Four Corners region, which will
increase high temperatures around the area again, but at this
time, will not compare to our latest heat event. Minor to Moderate
HeatRisk will remain in the forecast, and high temperatures are
forecast to be in the low 90s to around 105, with the Delta being
the coolest and the northern Sacramento Valley once again being
the warmest.
&&
.AVIATION...
VFR conditions next 24 hrs, except local MVFR possible vicinity
isolated thunderstorms northern Sierra 22Z until about 02Z
Saturday. Surface wind gusts generally below 12 knots except
southwest wind gusts 15-20 knots vicinity west Delta after 00Z
Saturday.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 9 PM PDT Saturday for Central
Sacramento Valley-Motherlode-Mountains Southwestern Shasta
County to Western Colusa County-Northeast Foothills/Sacramento
Valley-Northern Sacramento Valley-Northern San Joaquin Valley-
Shasta Lake Area / Northern Shasta County-Southern Sacramento
Valley.
Heat Advisory until 9 PM PDT Saturday for Burney Basin / Eastern
Shasta County-Carquinez Strait and Delta-West Slope Northern
Sierra Nevada-Western Plumas County/Lassen Park.
Red Flag Warning from 5 AM Saturday to 8 PM PDT Sunday for
Northern Sierra Including the Tahoe and ElDorado NF/S West of
the Sierra Crest-Stanislaus NF West of the Sierra Crest.
&&
$$
Area Forecast Discussion
National Weather Service Tucson AZ
227 PM MST Fri Jul 12 2024
.SYNOPSIS...Excessive heat continues across parts of southeast
Arizona this evening with temperatures then moderating over the
weekend into next week. Today and Saturday storms will mainly be
confined to the White Mountains and central/western Pima County.
Sunday into next week storm coverage will increase to cover most
of southeast Arizona with typical monsoon threats.
&&
.DISCUSSION...Sky has started to fill up with cumulus clouds with
some taller build ups. It is enough for the radar to pick up
returns in the Southeast Arizona. Latest RAP analysis has CAPE
values 500-1000 J/Kg, DCAPE close to 1900 J/KG, and the primary
moisture is sitting over Tucson to the west. The forecast for the
rest of the afternoon is still on track to have mainly isolated
thunderstorms around Tucson and a isolated-scattered towards the
western part of Pima County. The CAMs depict a more down-ish day
with only a handful of thunderstorms, but with the current trend
of the moisture slowly moving out to the west with dry air filling
behind it, it can help trigger some thunderstorms around Tucson
and the Sky Islands. Based on the storm environment, the storms
will struggle to maintain itself a little bit initially, but it
could gain better organization more into western Pima County due
to better shear environment. Plus, better chances for storms in
the western Pima County.
Heat will remain this afternoon. The Excessive Heat Warning will
expire at 8 PM MST tonight. Overnight lows will be elevated again
for tomorrow morning.
For the weekend, temperatures will trend down a bit through the
weekend. Moderate Heat risk is expected Saturday through most of
the new week. The High Pressure Center will transit away from the
Great Basin region and position itself over the Four Corners.
Thunderstorm chances will remain around Saturday, similar to this
afternoon chances and coverage. By Sunday, the high pressure will
be in an ideal position to bring more moisture back into the
region and resulting in better chances for thunderstorms and
showers. The ensembles show PWATS climbing back to 1.2-1.4 range
on Sunday and more on Monday; 1.4-1.8 inches with a few members
1.8-2.0 inches. With this forecast package, Sunday and Monday will
be more up days for the monsoon with Monday being the better day
for thunderstorms out of the two days based on the latest ensemble
models. After that, it will be day-to-day variability of
thunderstorms which we will have a better understanding by the end
of the weekend.
Temperatures next week will be around normal for the fist part of
the week and then trending back to the hot side by the end of the
week.
&&
.AVIATION...Valid through 14/00Z.
SCT-BKN clouds at 8k-12k ft AGL thru 13/04Z and again aft 13/18Z.
Diminishing cloud cover aft 13/04Z and generally clear skies/SKC
conditions between 13/07Z and 13/18Z. Isold/SCT TSRA/SHRA thru
13/04Z and again aft 13/19Z, mainly across central/western Pima
County and in the White Mountains. MVFR conditions in TSRA, with
mountain obscurations, vsby reductions and wind gusts to 40+ knots.
Outside of TSRA, SFC wind ELY/SELY at 8-14 kts with occasional gusts
to 22 kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Through Saturday, the best chances for storms will
be in central/western Pima County and in the White Mountains with
the main threats being strong winds and locally heavy rainfall.
Moisture increases on Sunday into next week leading to an expected
increase in storm coverage and heavier rainfall. Minimum relative
humidities through Sunday will range from 12 to 20 percent in the
lower elevations and 15 to 30 percent in mountain areas. Humidity
values increase Sunday into next week as greater moisture returns.
Away from thunderstorms, expect 20-foot winds to generally be 15 mph
or less, with afternoon/early evening gusts to 20-25 mph and light
winds overnight. Wind direction will be east/southeast through
Saturday, becoming westerly through the middle of next week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 8 PM MST this evening for
AZZ504>506.
&&
$$
Public...Strongman
Aviation...Zell
Fire Weather....Zell
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion
National Weather Service Las Vegas NV
1240 PM PDT Fri Jul 12 2024
.SYNOPSIS...One last day of excessive heat today as the pattern
begins to shift towards a monsoonal one. Expecting a first taste
this afternoon with strong thunderstorm outflow winds probable in
Mohave County and on the area lakes. Temperatures cool slightly this
weekend as storms become more numerous. Rain chances become more
isolated next week as drier air filters in from the west.
&&
.SHORT TERM...through the weekend.
The day is finally here! The final day of this excessive, extreme,
historic (insert your favorite descriptor) heatwave is upon us.
Highs today will once again threaten daily records at several
climate sites, but some relief is on the way. Monsoonal moisture
and more widespread convection/clouds tomorrow will bring
temperatures down sufficiently to allow the heat headlines to
expire. That being said, it is still going to be hot, with
temperatures remaining above normal through the weekend. Now,
let`s talk about storms.
The 500mb high that has long been positioned just to our west or
practically overhead is finally beginning to move to the Four
Corners area. Positioned just to our north today, there isn`t much
southerly component in the flow aloft, thus moisture remains rather
meager today. However, there will be just enough to spark
thunderstorms in eastern Mohave County this afternoon, with slightly
greater coverage than we saw yesterday. Like yesterday, the very dry
low-levels will make strong outflow winds the primary hazard with
any convection. Latest HREF shows 750-1000 J/kg of surface-based
CAPE atop 2000+ J/kg of DCAPE, suggesting an environment rather
favorable for strong thunderstorm outflow. And indeed, the CAMs have
latched on to this potential, with the HREF showing 30-60% chances
of 40+ mph wind gusts over central Mohave County and all the way to
the I-15 corridor in southern Nevada. What the outflow does when it
gets to the Las Vegas Valley is more uncertain. Some guidance has it
kicking off additional storms on the terrain surrounding the valley,
while others do not. This will be something to watch in subsequent
model runs and as the actual convection evolves this afternoon.
Should storms fire in the Las Vegas vicinity, strong winds will be
possible in the valley. In terms of rainfall, not expecting much.
HREF ensemble max 3-hr QPF tops out at ~0.5" on some of the high
terrain in Mohave County, but the ensemble mean remains less than
0.1".
Southeasterly winds aloft within the high`s anticyclonic flow will
usher in better moisture tomorrow and Sunday as it shifts east.
Latest EPS mean PWAT has values of 0.75"+ across much of the area,
with the 1.00"-1.50" values largely confined to the southern half of
the CWA. This moisture combined with slight cooling aloft will yield
CAPE values of 250-1000 J/kg for most of the area. Despite the
increase in moisture, low levels will remain relatively dry as temps
stay above normal. 12z HRRR soundings show DCAPE of 1500-2200 J/kg
from Bishop to Needles, suggesting strong outflow winds will
continue to be the primary hazard. Any flash flood potential is
confined to eastern Mohave County where WPC maintains a marginal
risk for excessive rainfall this weekend. In the Sierra and Owens
Valley, the combination of dry low levels, cured fuels, and
scattered thunderstorms will yield high fire danger this weekend.
Due to this threat, a Red Flag Warning is in effect for the area
Saturday and Sunday.
.LONG TERM...Monday through Thursday.
Monsoonal moisture from the weekend will linger to start the work
week, but a slight westerly component in the winds aloft will
gradually push the moisture eastward through mid-week. As a
result, PoPs of 20+ percent, which exist on the high terrain from
the Spring Mountains and points east on Monday, become confined to
eastern Lincoln and Mohave Counties Tuesday - Thursday. Main
concerns with most storms will be gusty outflow winds and dry
lightning, though convection in Mohave County and the Lower
Colorado River Valley will have the potential to produce isolated
flash flooding due to the greater PWAT values. Latest WPC ERO
gives paints this area with marginal risk of excessive rain (at
least 5% chance of occurring) on Monday.
For areas along and west of I-15, temperatures remain above normal,
though not expecting the blistering heat we`ve seen this week. Highs
across the Mojave Desert are forecast to be in the 100-115 range,
with lows in the 80s across our lower deserts and 60s/70s in our
northern locations. Combined, this should yield widespread Moderate
HeatRisk through the week.
&&
.AVIATION...For Harry Reid...For Harry Reid...Light east winds will become southeast
this afternoon. 15-20KT gusts are possible with the southeast winds,
especially after 21Z. There is a low chance for convection to impact
the terminals directly today with a 20% probability for thunderstorms
between 01Z to 05Z. However, watching the potential for strong
outflow winds from distance thunderstorms to push through this
evening. If these winds were to reach the terminals, it would be
between 01Z-04Z, likely as an east or southeast wind. Gusts over
35KT are possible with these winds.
After 06Z, a quiet night with dry conditions and light diurnal winds
tonight through Saturday morning are expected. Convection will
develop again Saturday afternoon after 20Z in and around the
terminals with chances for thunderstorm at the terminal higher
Saturday compared to today, around 40%-50%. Any thunderstorms could
bring lightning, brief rain, and sudden gusty winds. Will need to
watch the potential for more gusty outflow winds Saturday afternoon
from distant thunderstorms in the late afternoon and evening, which
are possible but confidence is too low for outflows at the terminal
to include them in the current TAF package. Outside of convective
influence, expecting breezy south to southwest winds Saturday
afternoon with a moderate (40%-50%) chance for gusts over 20KT.
Occasional SCT clouds around 15fkt-20kft are expected through the
TAF period.
For the rest of southern Nevada, northwest Arizona and southeast
California...Scattered thunderstorms will develop this afternoon in
western Arizona and southern Clark County. The highest risk for
thunderstorms will be in Mohave County as well as the Spring
Mountains and the terrain in far southern Clark County. Any
thunderstorms may produce lightning, brief rain, CIGs to 10kft, and
sudden gusty winds. Watching for an outflow to move out of northern
Mohave County this evening through southern Nevada, potentially
making it as far as Death Valley. There is a 40%-60% risk for sudden
gusty winds over 35KT through MOhave County and the northern
Colorado River Valley between 00Z-03Z, with lower chances around 20%-
30% in the southern Colorado River Valley, southern Clark County,
and southeast Inyo County. COnvection and the threat for sudden
gusty winds will dissipate after 04Z and a dry night with diurnal
wind trends is expected tonight.
Outside of the potential convection- winds today will favor the
south to southeast wind speed around 10KT and occasional gusts up to
20KT this afternoon. At KBIH, gusty west winds are possible after
21Z. Winds will become light and diurnal overnight and continue
through Saturday morning. More widespread scattered thunderstorms
are possible Saturday afternoon across much of the region, which
could bring additional gusty outflow winds and lightning to the
area.
&&
.CLIMATE...Numerous climate locations have a forecast high
temperature and/or forecast warm low temperature within 3 degrees of
the daily record.
The table below shows the daily record maximum temperature and the
year the record was last set. An asterisk (*) denotes which records
are in jeopardy (within 3 degrees of the forecast).
MAX FRI, JUL 12
RECORD (Yr)
Las Vegas 114(2003)*
Bishop 108(2020)*
Needles 124(1925)
Daggett 115(2021)*
Kingman 111(2020)
Desert Rock 112(2021)*
Death Valley 130(1913)*
The table below shows the daily record warm minimum temperature
and the year the record was last set. An asterisk (*) denotes
which records are in jeopardy (within 3 degrees of the
forecast).
WARM MIN FRIDAY, JUL 12
RECORD (Yr)
Las Vegas 94(2020)*
Bishop 69(1990)*
Needles 96(2021)*
Daggett 87(2012)*
Kingman 80(2021)*
Desert Rock 83(2023)
Death Valley 107(2012)
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
DISCUSSION...Woods
AVIATION...Nickerson
For more forecast information...see us on our webpage:
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