Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/01/24
Area Forecast Discussion
National Weather Service Bismarck ND
1009 PM CDT Wed Jul 31 2024
.KEY MESSAGES...
- Hot temperatures and drier conditions are expected Thursday
and Friday, with highs in southwest North Dakota just above
100 degrees on Friday.
- A cooling trend is expected to begin Saturday, with highs
decreasing into the 70s and 80s through next week. Daily
chances for showers and thunderstorms will return as well.
&&
.UPDATE...
Issued at 1002 PM CDT Wed Jul 31 2024
A quiet night continues across western and central North Dakota
with lows expected in the upper 50s to the low to mid 60s. Just
blended in the latest observations to the going forecast.
Aviation discussion also updated below.
UPDATE
Issued at 620 PM CDT Wed Jul 31 2024
Most of the showers and storms have moved out of the southeast
but there is still a slight chance of another isolated storm or
two in that area given the circulation evident on satellite
imagery, generally centered over the far south central. We will
also continue to see an isolated shower (maybe a stray rumble of
thunder) across the west over the next hour or two before
sunset. After that, we are looking at a dry and mostly clear
night. For this update, no major changes were needed other than
to back off precipitation chances southeast a bit and to blend
in the latest observations to the going forecast.
&&
.DISCUSSION...
Issued at 254 PM CDT Wed Jul 31 2024
The convection this morning across the south central has nearly
cleared our area completely, with multiple lines of convection
entering Minnesota from the west at the moment. A few showers are
present to the south of Dickey County, but these storms appear to be
in an environment that has been modified by the earlier convection
to the point where they are struggling to maintain themselves. As a
result, the severe threat for our area has ended, as well as most
chances for precipitation, with chances only lingering in the
southern James River Valley for the next few hours.
Surface high pressure has begun to enter the northwest, along with a
gradually weakening surface pressure gradient, which will help calm
winds heading into the evening and overnight hours. Some cumulus
fields have developed across the west as daytime heating ramps up,
with a few tiny cells picking up some radar returns in far
northeastern Montana. Given how dry the environment is up there,
we`re not too concerned about any storm development. There could be
a singular cell or two that strengthens to the point of dropping
some rain, but it still remains highly unlikely. The most recent
HRRR Smoke model run indicates that there`s a good chance the smoke
will finally be exiting the area later today, which will help get
rid of the constant hazy and smoky skies. This smoke should clear
from northwest to southeast through the evening today. Highs today
will mostly top out in the 80s across the area, with overnight lows
in the 60s.
From Thursday through Saturday, we are expecting to see a generally
warmer and drier pattern. Ridging over the western CONUS will begin
to nudge east into the Dakotas on Thursday, with the 850mb thermal
ridge most prevalent across the area on Friday. High temperatures on
Thursday are forecast to be in the mid 80s east to mid 90s west,
with temperatures increasing into Friday, where the current forecast
highs are exceeding triple digits in the southwest. We could see
temperatures around 101 and 102 in this area. While heat headlines
are not currently planned, if forecasted temperatures and heat
indices climb over the next 48 hours, we may need to evaluate this
hazard again. This stretch will generally be quiet weather-
wise, with mostly clear skies, light winds, and no chances for
precipitation until late Saturday night. While temperatures will
begin to cool on Saturday, highs will mostly be in the 80s and
lower 90s.
The aforementioned ridge will begin to flatten late Saturday night
into Sunday, with troughing to the north of it beginning to build
south. This will allow for shortwaves to begin digging into North
Dakota, bringing about daily chances for showers and thunderstorms.
These shortwaves will also help bring some cooler temperatures to
the area, as they descend south from Saskatchewan and Manitoba. A
cooling trend from Sunday through much of next week has been
relatively consistent over the past couple days, with high
temperatures decreasing into the 70s across the entire area by
Wednesday. This pattern will also be somewhat less conducive for
strong thunderstorm development, with the CSU machine learning
guidance not really suggesting anything in terms of severe risk
across the area. Its still a bit far out to be certain with regards
to the mesoscale setup these days, but given the gradually
decreasing temperatures and generally weak synoptic lift, showers
and thunderstorms will mostly be the typical spotty, short-lived
Summer showers. Long range guidance is leaning towards this pattern
continuing through the rest of next week and into next weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 1009 PM CDT Wed Jul 31 2024
VFR conditions are expected through the period with dry
weather and generally light/variable winds.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...ZH
DISCUSSION...Besson
AVIATION...ZH
Forecast Discussion at weather.gov/mqt.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...None.
&&
$$
DISCUSSION...Huyck
AVIATION...Britt
MARINE...Huyck
Area Forecast Discussion
National Weather Service Des Moines IA
329 PM CDT Wed Jul 31 2024
.KEY MESSAGES...
- Thunderstorms likely tonight with an Enhanced Risk of severe
weather over much of the forecast area. Although large hail
and a few tornadoes are in place, damaging winds are the
primary concern.
- Lingering chances for showers & a few storms north and east
Thursday
- Mainly dry this weekend
&&
.DISCUSSION...
Issued at 328 PM CDT Wed Jul 31 2024
The primary concern is obviously what is going to transpire
over the next 12-18 hours with another round of severe weather
and heavy rains anticipated. The airmass is becoming
increasingly unstable with MLCAPEs now approaching 4000 J/kg
west, however CINH is equally strong and still 100+ J/kg due to
a noted warm layer around 2km. This has suppressed even much
cumulus development. Forecast temps and heat indices have not
reached expected values due to morning convection lingering
longer than anticipated, but the sensible weather is still warm
and humid with dewpoints into the 70s so will leave the current
advisory in place until expiration.
This situation is expected to change later this evening however
as lift associated with the current Dakotas upper low is
expected to cross the MO River into IA. Vertical motion from
diffluence aloft and QG forcing is expected to cool the mid
levels and erode this warm layer allowing for convection to
rapidly develop to our northwest during the late afternoon or
evening hours, with a separate cluster likely occurring farther
southwest ahead of the current NE MCS. RAP forecast soundings
over western IA suggest MLCAPEs may reach 4000-5000 J/kg, mid
level lapse rates around ~9 C/km, and DCAPEs as high as 1500
J/kg. This alarming thermodynamic parameter space and very warm
airmass is very conducive for damaging winds, and both the 12Z
HREF and recent HRRR runs suggest that localized high end gusts
are possible (70+ mph). Recent HRRR runs have had good agreement
on this magnitude, but not placement, occurring anywhere from
the Siouxland area into MO. While the warm airmass and only
moderate effective shear ~40kts may temper the large hail
potential somewhat, and less than favorable 0-1km shear and SRH
aren`t ideal for tornadoes, the magnitude of the instability
and stretching/parcel acceleration potential keeps both of those
in play. With organized wind/bowing segments favored, the heavy
rain potential may be minimized due to the progressive nature
of the MCS, and the 12Z HREF reflects that as well with only
spotty 1-4" amounts, lesser than noted for previous events.
The severe weather potential should be over by Thursday, but
the parent upper low is expected to mature over the Upper MS
Valley with lingering forcing in eastern IA aiding precip
chances in the morning, and the low modifying the environment
such that steep low level lapse rates may produce showers and a
few storms, and possibly even a funnel cloud or two near the
core of the upper low.
By Friday and the weekend, although there won`t be a
significant change in airmass, surface high pressure should
dominate leading to mainly dry conditions and seasonal
temperatures and humidity. By early next week, the sprawling
Rockies upper high will become progressive enough that
increasing return flow and warm advection will return leading to
warmer temperatures, especially southwest. The models are in
good agreement that a northern stream short wave will bring
another frontal passage and chances for showers and storms
around Monday night, especially north, and this time leading to
a cooler temperatures and a more notable change of airmass.
&&
.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1255 PM CDT Wed Jul 31 2024
Convection lingers south of KOTM, but VFR conditions can be
expected there and elsewhere with mostly clear skies over much
of the area this afternoon. However a period of strong to severe
thunderstorms is anticipated tonight, with the potential
starting at TAF sites around 01Z-04Z west to east. The
confidence in occurrence is sufficient to include thunder at
this lead time. Generic, VFR conditions have been mentioned, but
MVFR/IFR conditions are certainly possible but will not be
included until trends become clearer. Confidence in VFR
conditions increases again Thursday morning after the frontal
passage.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT this evening for IAZ033>035-
044>048-057>061-070>075-081>086-092>097.
&&
$$
DISCUSSION...Hagenhoff
AVIATION...Small
Area Forecast Discussion
National Weather Service Grand Rapids MI
948 PM EDT Wed Jul 31 2024
.KEY MESSAGES...
- Thunderstorms Chances Exist This Evening Through Thursday Night
- Showers and Storms Possible Friday
- Dry Saturday, Chance of Storms Late Sunday, Larger System
Potentially Next Week
&&
.UPDATE...
Issued at 945 PM EDT Wed Jul 31 2024
The convection over MI continues to weaken as the atmosphere
stabilizes. The HRRR continues to show fog developing overnight
and some of it could be dense. No headlines at this time. Based on
the latest model runs, it looks like any convection later tonight
will likely hold off until after 12z Thu. We will feature only
very low POPs for the far southwest parts of the CWA including the
South Haven area.
&&
.DISCUSSION...
Issued at 329 PM EDT Wed Jul 31 2024
- Thunderstorms Chances Exist This Evening Through Thursday Night
Isolated to Scattered thunderstorms will be possible late this
afternoon and evening. The area that storms may occur looks to be
fairly limited though given a divergent lake breeze off of Lake
Michigan. This can be seen in both satellite imagery with a
clearing over Western Lower Michigan and in the obs along the
lakeshore that have diverging winds Muskegon and South Haven. The
best chance for storms will be in the late afternoon through mid
evening in the northeast CWA up towards Clare, Mt Pleasant and
areas nearby. Plenty of instability exists with limited shear. So
any storms will be of the pulse variety and likely non severe.
Cannot rule out an isolated severe report of wind given DCAPE over
1,000 and surface based CAPE values of 2500-3000 j/kg. Convection
will fade diurnally during the late evening hours. Areas of fog
are possible tonight given the high dew points and light winds.
Likely more of a general haze or light fog.
A wave diving southeast in the upper flow will bring the next
round of showers and storms Thursday afternoon into Thursday
night. Cloud cover with the approaching shortwave trough may
inhibit good heating and therefore instability on Thursday. The
trusted HREF is showing most unstable CAPE values topping out in
the 1000-2000 j/kg range which is modest by August standards and
deep layer shear of only 20 knots. We are still expecting showers
and storms but it may be muted a bit by the cloud cover and
possible activity moving in early in the day. The HREF is not
overly bullish on convection as the neighborhood probabilities
never really exceed 50 percent across our forecast area. The most
concentrated convection looks to be just south and southwest of
our CWA which can be seen in the day 2 (Thu/Thu night) SPC outlook
which has a slight risk southwest of us.
- Showers and Storms Possible Friday
Friday will begin the day with a strong upper level shortwave
moving through the midwest with warm air advection and anomalous
PWATS of 1.5 to 2 inches. Warm, humid air along with daytime
heating should provide another good opportunity for storm
formation. The question that will be, and has been all week, is
whether or not the system will provide enough shear. There remain
some questions of timing and movement of the low. It could trend
to the south with the best shear through Indiana and Ohio. Given
the current passage and timing of the low, the best area for
convection will be in the far SW corner. If any showers or storms
do form, expect them to have locally heavy rainfall.
- Dry Saturday, Chance of Storms Late Sunday, Larger System
Potentially Next Week
The before mentioned upper level shortwave will exit the region
Saturday with a positively tilted upper level ridge that will
coincide with warm dry air through the first half of the weekend.
The trend for a pattern change Sunday remains in place, as a large
upper level low over eastern Canada will dominate the weather
pattern into next week. That low will bring successive waves and
moisture boundaries across the region. Previous discussions talked
about a cold front moving through the region and latest runs
stall that front and bring it through closer to Sunday night.
Showers and storms will be possible along the front through that
timeframe. Cooler and drier air will begin the weekend with
another chance for showers and storms Tuesday. Models diverge on
timing but there is a decent signal for a another storm event
around mid next week. There seems to be solid warm air advection
out ahead of the approaching system. Definitely a system that
bares watching.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 746 PM EDT Wed Jul 31 2024
A moisture rich near surface environment with light winds will
support fog development late tonight into early Thursday morning.
Fog may drop down to less than one mile at times. Fog will mix
out after sunrise quickly turning back to VFR for the rest of the
day. Afternoon showers and storms will be possible after 20z
Thursday.
&&
.MARINE...
Issued at 329 PM EDT Wed Jul 31 2024
Limited concerns for high winds and large waves over the course
of the remainder of the week and upcoming weekend. It is not out
of the question that we could see our advancing high setup over
the weekend during the afternoon hours. Overall however, we are
do not have any major synoptic scale systems that will be
generating wind.
Our main marine concerns over the next couple of days will be some
fog/haze and the chance for thunderstorms. The moisture advecting
over cooler water (surface dew points higher than the water
temperature) is producing some light fog and haze over the water
this afternoon. Nothing too significant at this point, but some
areas of fog are possible tonight. These conditions will continue
into Thursday. Chances for thunderstorms will exist over Lake
Michigan from Thursday into Friday. The stronger storms may
contain locally heavy rain, lightning strikes, small hail and
gusty winds to 35 knots. Winds and waves will be higher in and
near storms the next couple of days.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
UPDATE...MJS
DISCUSSION...Duke/Ceru
AVIATION...Thielke
MARINE...Duke
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
907 PM CDT Wed Jul 31 2024
.KEY MESSAGES...
- Another round of storms will move across the region late tonight
into Thursday morning. There is a slight risk (level 2 of 5) for
severe storms with this system with damaging wind gusts the
primary concern.
- Heat and humidity may result in heat indices in excess of 100
degrees Thursday, especially south of I-72. Confidence is too
low for a Heat Advisory at this time due to uncertainty in storm
track/timing and possible lingering cloud cover.
&&
.UPDATE...
Issued at 906 PM CDT Wed Jul 31 2024
Have updated timing of thunderstorm chances through Thursday
morning as a bowing line of thunderstorms over southern
IA/northern MO heads eastward around 50 mph, and additional
clusters of thunderstorms over eastern KS shift eastward as well.
Severe wind gusts to 65 mph and wind damage continue to be
reported with the IA feature as it moves into an axis of
3500-5000 J/KG MLCAPE that extends from east central MO into NW
IA, however RAP based mesoanalysis indicates it will be moving
into an area of under 1000 J/kg in central IL struggling to
recover from being worked over from today`s convection. The 00Z
HRRR run begins to weaken the convective line dramatically in
eastern IA, however convection currently over KS then intensifies
as it crosses the instability axis and arrives in central IL a
little later than previous runs that expected the IA convection to
dominate. Despite the variety of model runs coming in lately, it
would appear chances for thunderstorms arrive in west central IL
around midnight to a few hours after midnight and spread eastward
through the early morning, and should be fueled by up to 2000
J/kg MUCAPE, a low level jet nosing into the area, and a
convectively induced shortwave creating 30-40 kt bulk shear and
lift. A Slight Risk for severe thunderstorms continues to be
designated by SPC, mainly for severe wind gust potential.
Otherwise, changes this evening are minimal, with warm lows in the
mid 70s maintained by southerly winds as the warm front located
just south of the area this evening lifts northward in the
overnight.
37
&&
.DISCUSSION...
Issued at 153 PM CDT Wed Jul 31 2024
THROUGH TOMORROW MORNING...
This afternoon, a couple boundaries from earlier storms are noted
on satellite imagery, the closest stretching from near Quincy to
near Lawrenceville. To the north, temps have been suppressed by
convective debris and are generally running in the 70s to lower
80s. Further south upper 80s and 90s are noted. A sharp
instability gradient is the result with the warm side of the
boundary characterized by 3000+ J/kg MLCAPE values. This will
likely be the focus for additional storms this afternoon, mainly
impacting our far southern counties in the CWA adjacent to the St
Louis and Paducah forecast areas. Most of central Illinois north
of I-72 should be dry through the afternoon.
This evening, low level jet is progged to strengthen to our west
with storms redeveloping on the nose of the LLJ over NW MO/SW IA.
These storms will grow upscale and track east into central Illinois
on the veering LLJ late tonight into Thursday morning. Moderately
strong MUCAPE in excess of 2000 J/kg is progged to be in place ahead
of the advancing line of storms and will support its maintenance
overnight as they track east towards the local area similar to the
past couple nights. A severe threat will accompany the line but
should gradually wane with time and eastward extent.
THURSDAY...
A closed H5 low will track slowly southeast from southern MN
Thursday morning to central IN Friday evening. Ongoing storms
Thursday morning will leave outflow boundaries across central
Illinois that will interact with the approaching upper level
disturbance and serve as the foci for the next round of storms
across portions of central Illinois. There is some uncertainty on
location of these boundaries. Moderately strong instability is
expected to develop Thursday afternoon with MLCAPE in excess of
3000 J/kg while sufficient deep layer shear of around 30 kt will
be in place supporting strong to severe storms.
Heat and humidity continue to be a concern Thursday afternoon with
potential for heat indices to exceed 100 degrees. As has been the
case the past couple days, morning storms, convective debris and
cloud cover add considerable uncertainty to the temp forecast and
will hold off on issuing any heat headlines. If clouds hold on
longer than expected or storms form earlier, temps may hold in the
80s. If full sunshine breaks out for several hours, temps should be
able to warm into the 90s and a heat advisory may eventually be
needed.
Surface cold front will sag south across central Illinois Thursday
evening and overnight and will support a chance for additional
showers and storms. Unfavorable diurnal timing resulting in
diminishing instability and gradually weakening deep layer shear
should limit the severe threat Thursday night, but wouldn`t rule out
a few stronger storms.
FRIDAY...
Main H5 low will pass across central Illinois Friday with
scattered showers and storms expected with its passage. Northwest
winds behind the front will help usher in less warm temps with
highs in the lower to mid 80s Friday afternoon. This will keep
instability modest and help limit the chance for severe storms
Friday.
SATURDAY THROUGH WEDNESDAY...
High pressure will build across the region this weekend and
linger into early next week favoring a stretch of mainly dry
weather across central Illinois. Temperatures will be more
seasonable over the weekend with highs in the mid to upper 80s,
though a few 90s will creep back in early next week as upper
ridging builds over the west and Great Plains and inches eastward.
While temps will be slightly more subdued, humidity levels will
remain high with dew points generally running in the upper 60s to
lower 70s.
Deubelbeiss
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 639 PM CDT Wed Jul 31 2024
A line of thunderstorms, potentially remaining severe, is likely
to affect the central IL terminals overnight. While timing is
still not certain, latest blend of model and observations of the
developing line suggests the first impacts in the KSPI-KPIA area
by 07Z, sweeping eastward to KCMI by around 09Z. Trailing showers
and thunderstorms could last until around 14Z. Expect MVFR or
worse vsbys and perhaps cigs as well, with strong gusty winds that
could briefly exceed 40 kts in thunderstorms. Until then, VFR
conditions are expected. Another round of thunderstorms is
possible Thursday afternoon. Winds light and variable to SSE
around 8 kts tonight, becoming SW 6-10 kts by 14Z.
37
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
951 PM EDT Wed Jul 31 2024
.KEY MESSAGES...
- Uncertainty remains high on thunderstorm coverage and timing
through tomorrow night
- Heavy rain/flooding and some severe storm potential exists
- Heat indices near or above 100 degrees possible Thursday
afternoon
- Drier conditions this weekend into early next week with a
warming from near normal to above normal once again
&&
.FORECAST UPDATE...
Issued at 950 PM EDT Wed Jul 31 2024
The main issue with the update will be timing and paths of upstream
MCS activity, currently over the upper Midwest south to Kansas.
Earlier convection today over central Indiana stabilized the
atmosphere for a but, but instability has since rebounded north of I-
70 and the highest CAPEs continue to be across the lower Wabash
Valley and into southern Illinois. An upper trough, seen on H20
vapor imagery, over the northern Plains is expected to move into the
upper Midwest by daybreak. This feature will supply synoptic forcing
to the convective complexes and deep shear vectors will be mostly
from west to east with a near perpendicular component to any linear
convective systems. Meanwhile, a modest nocturnal jet will feed into
the systems. Currently, the CAMS have a line of storms associated
with merging convection into the upper Wabash Valley around 12z.
That said, CAMS are usually a bit slow as the do not handle cold
pools well. In addition, the stronger storms may tend to move
further southwest toward the greatest instability. With the
uncertainty, keeps PoPs low until after 10z at which time PoPs
increase to likely over the Wabash Valley.
Isolated storms remain possible through the remainder of the evening
and overnight associated with warm advection, an unstable
atmosphere, a moist boundary layer and remnant boundary, across far
southwestern Indiana.
&&
.MESOSCALE UPDATE...
Issued at 452 PM EDT Wed Jul 31 2024
The bow echo accompanied by a rear inflow jet has moved south and
east of Jennings county. This prompted an earlier severe
thunderstorm warning as the line moved into better shear balance and
low level lapse rates increased as a 60+ knot base velocity
signature popped up along the northern edge of the line. However,
the activity has moved off to the east which will result in the
cancellation of the Severe Thunderstorm Watch. Areas near and north
of I-70 have been worked over and should not longer be a big concern
tonight but would not completely ruled out additional isolated to
scattered convection, in warm advection, south of the I-70 corridor,
where the atmosphere is much more unstable with LAPS data indicating
SB CAPEs to 2500 J/kg. HRRR reflectivity progs are going along with
this potential scenario.
&&
.SHORT TERM (This evening through Thursday)...
Issued at 251 PM EDT Wed Jul 31 2024
The most intense convection today has reformed south of residual
cold pool in reservoir of stronger instability across roughly the
southern third of central Indiana. This convection should continue
to overturn the low-level thermodynamic environment and perpetuate
further southward expansion of effective cold pool, limiting further
thunderstorm development into the evening. Midlevel overcast will
be present in the wake of remnant MCS.
With complicating factors of today`s convection and weak flow to
replenish the low-level moisture, convective development late
tonight is in question. As is potential MCS maintenance tomorrow
morning. We think modest west-southwesterly 850-mb flow helping
advect deeper moisture in and increasing large scale ascent from the
approaching trough should be enough for some isolated convection
later tonight, though spatial details on this development remain
uncertain. This modest moisture advection may help maintain any MCS
that evolves from convection upstream as well, though this may
preferentially propagate further south than most CAMs currently
anticipate along residual cold pool periphery. At least the more
intense part.
Tonight/tomorrow`s scenario will continue to influence the mesoscale
environment which will drive convective coverage and intensity late
tomorrow. However, forcing for ascent with the trough and
strengthening warm advection coupled with diabatic surface heating
should lead to an uptick in convection late tomorrow somewhere
across the area. Modest effective shear and sufficient instability
will support some severe threat, with damaging winds being the
primary concern, especially if a more organized cold pool-driven
forward propagating system can evolve. Anomalous moisture will
continue to support some heavy rain/localized flooding threat,
especially if training happens.
Bottom line, mesoscale details that cannot yet be resolved will
drive the important details of the forecast, with regards to storm
timing and associated hazards. Thus, confidence is lower than
typical given the pattern and frequent forecast updates will be
needed through the short term period.
&&
.LONG TERM (Thursday night through Wednesday)...
Issued at 251 PM EDT Wed Jul 31 2024
A couple of notes based on the latest model cycles. Please see the
previous discussion below.
1. Broadening deep low over our area Friday will shunt the stronger
IVT and deepest moisture southeast by early Friday. Remnant low-
level moisture and convergent flow pattern will support extensive
clouds and numerous showers with locally heavy rainfall/flooding
potential. Organized heavy rain and flooding will decrease during
the day. Have trended temperatures down slightly with
clouds/showers.
2. With aforementioned low detached from main polar jet, we won`t
see an intrusion of dry continental air, and will thus remain
moist/humid. Weak perturbations within west-northwesterly flow aloft
may be enough for periodic chances of convection through the long
term period, but it remains difficult to identify a period of
stronger forcing and greater coverage at this time.
--previous discussion--
Friday and Saturday...
An upper low will move south into the area and a surface cold front
will move through on Friday. This forcing will interact with the
still plentiful moisture to produce widespread showers and some
thunderstorms across the area. Will go at least likely category PoPs
all areas. Heavy rain and flooding will remain threats.
Clouds and rain will keep temperatures in the 80s.
As the upper system moves east on Saturday, enough forcing will
remain for chance PoPs most areas. Highs will be in the mid to upper
80s.
Sunday and beyond...
High pressure will keep the area dry Sunday into Tuesday for most
areas. The upper ridge will try to sneak back in from the southwest,
bringing some 90s back into the area, especially south.
A cold front may be able to get into the area on Wednesday,
depending on how strong the upper ridge is. This may spark a few
showers or storms. Hot temperatures will continue south ahead of the
front.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 719 PM EDT Wed Jul 31 2024
Impacts:
- Thunderstorms with MVFR and briefly worse conditions are possible
mainly after 11z Thursday
Discussion:
Isolated thunderstorms are possible this evening. Better chances for
storms will be Thursday, however coverage and timing is too
uncertain to throw in the TAFs at any one given time. A lot of the
uncertainly hinges on whether or not the atmosphere can recover
from convection earlier today. MVFR and briefly worse visibilities
and ceilings are possible in convection.
Winds away from convection will be SSW mostly 10 knots or less and
very light tonight. Higher gusts are possible in thunderstorms.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...MK
SHORT TERM...BRB
LONG TERM...BRB/50
AVIATION...MK
Area Forecast Discussion
National Weather Service Medford OR
830 PM PDT Wed Jul 31 2024
.DISCUSSION...A "front" of smoke has traveled from the north and
is beginning to affect portions of the Umpqua and Rogue Valleys.
The Illinois Valley may not be far behind. Have updated the
forecast to account for this in the next couple of hours, but it
is worth noting that the HRRR smoke model is not seeming to
initialize very well. That being said, we may get a little relief
from the smoke tomorrow afternoon and evening. Otherwise, will
continue to monitor for any additional updates. For more
information on the forecast, please see the previous discussion
below. -Schaaf
&&
.PREV DISCUSSION... /Issued 458 PM PDT Wed Jul 31 2024/
DISCUSSION...Current satellite shows the smoke from the fires in
Lane County has moved into Douglas County including Roseburg with
less than a mile visibility. This smoke will continue moving
south this evening, so parts of Jackson and Josephine counties,
including Medford, could see smoke impacts from this string.
Stratus is still present at the coast and offshore, but there is
some sunlight coming through.
This afternoon has a jump in heat with highs from the mid-70s at the
coast to near triple digits for west side valleys. Temperatures will
not recover much overnight, and there is only a 10-20% probability
for Medford to fall below 65 degrees, and a 30-40% probability for
Roseburg. This heat will only increase for inland locations Thursday
with highs in the 100-105 degree range for west side valleys
(including the Klamath River and Shasta valleys). With this in mind,
a Heat Advisory will be in effect tomorrow afternoon through
tomorrow afternoon for west side valleys. Friday morning`s
temperatures will be similar to Thursday.
Checking back into cloud cover, there will be stratus once again at
the coast that will likely reach parts of the Coquille Basin. Being
in between the high pressure to the east and low pressure to the
west gives northern California and Southern Oregon the position to
gain southerly winds back tomorrow. There will be an increase in
high clouds that come from the south through the day tomorrow.
However, this southerly flow will bring smoke from the Park Fire in
Northern California to Siskiyou and Modoc counties tonight and it
will continue moving into southern Oregon through the day tomorrow.
Tomorrow afternoon and evening will be the worst for the Rogue
Valley and east into Klamath Falls. With the continued issue of
worsening air quality, an Air Quality Alert has been issued through
Friday for Klamath and Lake counties. Intermittent smoke is
possible in Jackson, Josephine and Eastern Douglas counties.
By the end of the work week, thunderstorms are in the forecast.
Starting Friday afternoon, the main area will be the Cascades,
northern Klamath County and parts of Siskiyou County. This trend
continues with more confidence on seeing thunderstorms in northern
Lake and Klamath counties Saturday afternoon with SPC guidance
showing a 40-50% probability of thunderstorms in the area. Ensembles
are showing that areas east of the Cascades could see a few
hundreths for rainfall, and overall less than a tenth of an inch is
in the forecast, although locally higher amounts are possible.
-Hermansen
AVIATION...01/00Z TAFS...IFR/LIFR marine stratus is affecting the
immediate coast near Cape Arago, just offshore of Bandon, near
Cape Blanco, and also south of Pistol River to Brookings. These
ceilings will press inland about 10 miles tonight (to include North
Bend), but a little farther than that into Coquille/Myrtle Point
over interior Coos County. These last until 16-18Z Thursday before
clearing to VFR.
VFR will prevail inland for the next 24 hours, except wildfire smoke
will become much more widespread overnight into Thursday. Earlier
today, the smoke briefly lowered visibility to IFR at Roseburg
(along with an MVFR ceiling), before vertical mixing pushed the
smoke out to the south and east. All of Roseburg, Medford and
Klamath Falls will likely see at least some visibility reductions
due to wildfire smoke/haze on Thursday, generally in the 3-5
mile range. Closer to the eastern Lane/Douglas fires and the Park
fire, visibility due to smoke could even be IFR or lower at times.
-Spilde
MARINE...Updated 230 PM Wednesday, July 31, 2024...North winds
and steep seas around 6 to 7 feet briefly return to an area between
Cape Blanco and Brookings through tonight. More low clouds and lower
visibilities are anticipated along the coast. Improved conditions
follow Thursday and Friday. North winds over the weekend are likely
to remain below advisory levels, although seas are anticipated to be
steep in the southern waters at times. Then, a stronger thermal
trough is possible early next week.
-Smith
FIRE...Issued 200 PM Wednesday July 31, 2024...High pressure builds
over the region resumes control today. This will bring the return
of hot temperatures and low daytime humidities, with triple
digits for West Side Valleys, and mid-upper 90s for East Side
likely lingering through the weekend and into early next week. The
peak of the heat is expected Thursday, and this is also when we
expect daytime humidities to bottom out. The flow turns southerly
on Thursday, and this will allow for an uptick in afternoon
breezes on Thursday, especially east of the Cascades and in the
Shasta Valley. Guidance has trended slightly stronger with
southerly winds, and this was enough to push conditions into the
critical category for portions of Siskiyou County and the southern
Oregon Cascades. This will mainly affect the Shasta and Scott
Valleys, but will include the eastern periphery of the Shelly fire
as well as the southern most portion of FWZ 623, south of Highway
140. Near critical conditions are possible for much of the East
Side and the rest of northern California on Thursday, but winds
won`t quite reach criteria there. Recoveries will trend lower
Thursday and Friday mornings, with the poorest recoveries
(moderate to poor) expected Friday morning east of the Cascades
and across northern California. Recoveries improve Saturday and
Sunday mornings with the influx of monsoonal moisture.
This brings us to the thunderstorm potential for the weekend as
southerly flow pumps moist, unstable air into the region.
Thunderstorm chances enter the forecast first on Friday afternoon.
Moisture will just be entering the region, so chances (15-20%) are
limited to the higher terrain of western Siskiyou County, across the
Siskiyous and Cascades. Moisture and instability will be marginal
and there really isn`t a clear trigger, but where the elements line
up best, which leads to the best chance for thunderstorms, is along
the Cascades from Crater Lake northward to areas eastward around
Chemult/Crescent.
Saturday and Sunday, however, moisture will be more widespread and
there is a more well defined trigger (moreso Saturday than Sunday).
These are the days we expect thunderstorm activity to peak,
including west of the Cascades, with slightly higher confidence for
Saturday being the more active day. Current guidance is increasing
confidence for scattered thunderstorms on Saturday, especially east
of the Cascades.
The nocturnal thunderstorm threat is not out of the question for
Friday night, it`s just a matter of when the moisture arrives and
whether that lines up with any elevated instability and a trigger.
Instability looks muted on Friday night, but there is a fairly
decent trigger coming through late Friday night into early Saturday
morning and this raises the concern for nocturnal storms. In
addition, any lingering cloud cover Saturday morning could impact
thunderstorm potential for Saturday afternoon.
Subtle changes in these elements could lead to big changes in the
forecast, and at this point in the forecast, it`s challenging to be
confident in any of the details. Stay tuned for updates, with
changes to the forecast likely over the coming days. /BR-y
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning from 2 PM to 8 PM PDT Thursday for ORZ623.
Heat Advisory from 2 PM Thursday to 8 PM PDT Friday for ORZ023-
024-026.
CA...Red Flag Warning from 2 PM to 8 PM PDT Thursday for CAZ280>282.
Heat Advisory from 2 PM Thursday to 8 PM PDT Friday for CAZ080-
081.
PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Thursday
for PZZ356-376.
&&
$$
Area Forecast Discussion
National Weather Service Morristown TN
1010 PM EDT Wed Jul 31 2024
...New UPDATE...
.UPDATE...
Issued at 1000 PM EDT Wed Jul 31 2024
Another update to keep a chance of showers and storms going for
most of the night with the line that moved through the northern
sections of the CWA between 7 PM EDT and the current time. Some
storms could be strong still late this evening south and produce
heavy rainfall at times so flooding risk continues overnight but
should lower late tonight as showers and storms move out.
However, some short range models develop more convection between
06Z and 12z across the northern half of the region.
&&
.UPDATE...
Issued at 730 PM EDT Wed Jul 31 2024
Updated forecast to increase rain chances along the northern TN
border and into Southwest Virginia for the rest of the evening.
Line of showers and storms are moving east southeast into northern
areas. DCAPE values are around 1200 to 1400 J/KG. Also with the
wet soils from earlier heavy rainfall today expect a renewed
threat for flooding with FFG values around 0.5 inches or less
northern plateau counties. Expect activity to slowly diminish
later this evening but new activity is possible in northern areas
late tonight. Updated forecast already sent.
&&
.SHORT TERM...
(This evening through Thursday)
Issued at 301 PM EDT Wed Jul 31 2024
Key Messages:
1. Our chances for severe weather and flooding are now lower through
the rest of the afternoon and evening.
2. Still a chance for an overnight MCS to move down out of KY but
low confidence.
3. Additional chances for showers and storms tomorrow.
Discussion:
The severe weather and flooding threat have decreased through the
rest of this afternoon and evening. The showers and storms from this
morning continue to linger across the central TN valley and points
northward. Rain cooled air and clouds have allowed a relatively
stable airmass to remain in place through the day. Showers and a few
storms will continue through early evening but will then dissipate.
If we were to see any stronger storms it would mostly likely be
across the central and southern Cumberland Plateau and southern TN
Valley, where instability is much higher. However forcing and shear
is weak for these locations. So overall, a very low severe threat.
If it weren`t for the possibility of an overnight MCS still moving
through, I would drop the flood watch. However, there is still a
chance, albeit low. The models have been all over the place with the
overnight MCS: some runs it`s there then it`s gone. The latest HRRR
(17Z) shows an MCS that will drop down into our area from out of KY
around 08Z and then progress south into the central TN Valley around
daybreak. If this scenario occurs, another round of moderate to heavy
rain may be in store for some areas. For this reason, will leave the
flood watch as is. The main threat with this MCS, if it occurs,
would be localized flooding. A few strong wind gusts are possible
but not expected to be widespread.
Overall, there is a chance of showers and storms through the day
tomorrow as well. The higher chances will be across northeast TN and
southwest VA due to high pressure shifting east. How tomorrow`s rain
and storms play out are very uncertain though because it all hinges
on what the overnight MCS does, if it even occurs. Lingering showers
and storms tomorrow morning would likely prevent much afternoon
activity. If the MCS doesn`t happen then look for better chances of
showers and storms during peak heating. Speaking of heating. There
is a chance that the southern TN Valley may need a Heat Advisory for
tomorrow. Due to uncertainty with the overnight MCS though
(lingering cloud cover into tomorrow), will hold off on the advisory
for now and future shifts will reassess.
&&
.LONG TERM...
(Thursday night through next Wednesday)
Issued at 301 PM EDT Wed Jul 31 2024
Key Messages:
1. Ridging begins to build in mid to late week with heat index
values near 107F possible between Chattanooga and Knoxville Friday
afternoon.
2. Continued MCS thunderstorm chances Friday into Saturday. Damaging
wind gusts and heavy rain rates are main threats.
Discussion:
Shortwave ridging will occur on Thursday night which give the soil a
break from all the rain. Unfortunately, it won`t be long enough.
Another trough will translate across the Great Lakes and Ohio River
Valley on Friday. Apparent temperatures (i.e. heat index) Friday
afternoon will be over 100 degrees to as high as 107 degrees in the
Tennessee Valley. A heat advisory will be needed mainly across the
southern Valley on Friday. Additionally, scattered showers and
thunderstorms will be possible in the afternoon. Locally heavy rain
will be possible and damaging winds.
The trough will be slow to drift east on Saturday. Therefore
temperatures might be slightly cooler than Friday but lingering
rainfall will persist into Saturday afternoon. Saturated ground
could become a problem with additional heavy showers. Turn around,
don`t drown!
By Sunday, conditions begin to dry out through early next week and
temperatures return to near normal.
&&
.AVIATION...
(00Z TAFS)
Issued at 730 PM EDT Wed Jul 31 2024
Mostly VFR conditions CHA and TYS expected through the period.
At TRI a line of showers and storms may affect the site this
evening. Expecting the line to decrease in next couple hours so
just have vicinity showers for now. May have to amend if activity
changes, strengthens. Then expect MVFR fog late tonight at TRI.
Thursday there is much uncertainty with how showers and storms
will develop across NE TN so have 2 prob30 groups at TRI for
morning and afternoon. At TYS and CHA expect mostly fair skies and
light winds and lower chances of showers and storms.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 76 95 76 97 / 10 20 0 40
Knoxville McGhee Tyson Airport, TN 73 92 75 95 / 30 30 10 50
Oak Ridge, TN 73 92 74 94 / 40 30 10 50
Tri Cities Airport, TN 69 85 72 91 / 30 40 30 50
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Flood Watch until 5 AM EDT Thursday for Cherokee-Clay.
TN...Flood Watch until 5 AM EDT /4 AM CDT/ Thursday for Anderson-
Bledsoe-Blount Smoky Mountains-Bradley-Campbell-Claiborne-
Cocke Smoky Mountains-East Polk-Grainger-Hamblen-Hamilton-
Hancock-Hawkins-Jefferson-Johnson-Knox-Loudon-Marion-McMinn-
Meigs-Morgan-North Sevier-Northwest Blount-Northwest Carter-
Northwest Cocke-Northwest Greene-Northwest Monroe-Rhea-
Roane-Scott TN-Sequatchie-Sevier Smoky Mountains-Southeast
Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi-
Union-Washington TN-West Polk.
VA...Flood Watch until 5 AM EDT Thursday for Lee-Russell-Scott VA-
Washington VA-Wise.
&&
$$
SHORT TERM...TD
LONG TERM....AC
AVIATION...TD
Area Forecast Discussion
National Weather Service Pocatello ID
205 PM MDT Wed Jul 31 2024
.SHORT TERM...Tonight through Thursday Night.
Early afternoon satellite imagery shows clear skies over SE Idaho
outside of some fair weather CU building over the higher terrain
as a H5 ridge of high pressure continues its progression north. As
a result, quiet and dry conditions have returned as temperatures
will a warming trend through Saturday. Highs today will be in the
70s and 80s, climbing around 5-10 degrees for Thursday into the
80s and 90s. Winds will remain light and variable given weak 700
mb winds aloft. Have added the mention of patchy smoke to the
forecast through tomorrow which while concentrations will remain
very light in some places, the HRRR smoke model does show
increasing concentrations lifting NE out of the Great Basin
tomorrow given predominant SW flow back overhead. MacKay
.LONG TERM...Friday through next Wednesday.
We will be in the worst of the heat this Friday and Saturday
thanks to a ridge of high pressure almost directly on top of
Eastern Idaho. This heat will be the biggest weather impact as
highs reach the mid to upper 90s and even a few triple digits both
afternoons through the eastern Magic Valley, Snake Plain, and
valley locations in the South Hills. Around Pocatello, there is a
10 to 30 percent chance of exceeding 100 degrees on Saturday. That
chance increases farther west near Shoshone with a 60 to 70
percent chance on Friday and a 40 to 60 percent chance on
Saturday. Morning temperatures will range from 50s to low 70s in
the valleys on Saturday morning, so debated on an Excessive Heat
Watch, but have decided to hold off for now as this heat looks
like a Heat Advisory at best, and even that is borderline. Either
way, with or without heat products out, the heat will be rough on
Friday and Saturday.
The second half of the weekend will be slightly cooler thanks to
a weak shortwave moving through to loosen the grip of the high
pressure. This will allow monsoonal moisture to also return for
the afternoons once we get to Sunday through Wednesday. As for our
highs, this will mean we cool all the way down to...low and mid
90s by Sunday afternoon. Highs will remain steady for Monday and
Tuesday, but we will drop a few degrees for Wednesday with highs
mostly in the upper 80s to low 90s, closer to our climate normals
for early August. AMM
&&
.AVIATION...For the 18Z TAFS through 18Z Thursday.
High pressure begins to build in over the area today which will
lead to hot and dry weather with VFR conditions. Winds will be
light today and tomorrow with limited clouds aside from afternoon
CU off of the mountains. No rain or storms are expected today or
tomorrow. Smoke from wildfires has cleared a bit behind
yesterday`s system leading to little to no impacts. Some light
smoke will return overnight, though 6SM VIS may be too
pessimistic. AMM
&&
.FIRE WEATHER...
Under the increasing influence of high pressure, conditions will
remain very dry with light winds as temperatures see a warming
trend through the weekend. Highs will peak on Friday and Saturday
in the 90s to low 100s with RHs bottoming out in the single digits
and teens. As an approaching H5 trough in the NE Pacific allows
the ridge axis of high pressure to shift east, monsoon moisture
will be allowed to advect north this weekend with showers and
thunderstorms then possible into early next week. While coverage
will remain more isolated in nature on Saturday, scattered
coverage on Sunday may necessitate a RFW issuance of which those
chances will continue each day through Wednesday. Coverage of
showers and storms will peak during the afternoon and early
evening hours each day as temperatures slightly cool with highs
returning to the 80s to mid 90s. MacKay
&&
.AIR QUALITY...
Air quality alerts have been lifted for Eastern Idaho as the
overall air quality has improved behind the trough that moved
through yesterday. Wildfire smoke is forecast to remain light for
the rest of today and most of tonight, though we will see an
uptick again tomorrow. At this point, Idaho DEQ is forecasting air
quality to remain in the "Moderate" category through Friday and
we`ve kept a mention of patchy smoke in the forecast. AMM
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Reno NV
1204 PM PDT Wed Jul 31 2024
.SYNOPSIS...
* Above average temperatures through the middle of next week.
* Smoke from nearby wildfires will continue to impact portions of
northeast CA and western NV through the weekend.
* Increasing thunderstorm chances late this week through the
weekend.
&&
.DISCUSSION...
Smoke: The Park Fire in northern California has continued to spew
out a considerable amount of smoke overnight. The winds have gone
light-northwesterly overnight causing smoke to settle over western
NV including the Reno area. This smoke and haze will likely linger
through Friday as per the HRRR smoke output. To reiterate, we still
recommend everyone to be air quality conscious the next few days.
For a very good way to view the AQI in your area we recommend
going to fire.airnow.gov.
Temperatures: Starting today, temperatures will be back on the rise
into the upper 90`s across lower valleys and upper 80`s in the
Sierra. By tomorrow, lower NV valleys will crack the 100 degree mark
yet again. That heat will carry into next week as we`ll get a Four
Corners High that`ll take charge over the southwest US.
Extended: With that high pressure system in place late-week, we`ll
have a stream of moisture come up from the south. Models have been
consistently showing PWATs of around 1" on Friday through this
weekend. Daytime heating combined with this increased moisture will
create the chance for afternoon/evening thunderstorms across western
NV then extending further north into northeast CA Friday night and
Saturday. Based on current soundings, Friday`s storms will be fast
moving and will likely have lightning, but also have the high
potential for localized heavy rain. Current QPF ranges from 0.10-
0.30", so nothing terribly heavy but if storms start to train there
could be a flash flood threat.
-Justin
&&
.AVIATION...
We`re going to see lingering smoke and haze at most terminals today
and tomorrow from the Park Fire in northern California. There will
be periods of visibilities 3-6 SM and CIGs BKN030-040 in the evening
and overnight hours. Due to the winds being light and northerly
overnight, smoke will continue to impact western NV and especially
northeast CA through Friday morning.
Looking ahead to Friday, as it stands right now there will likely be
the chance for a combination of smoke and thunderstorms across the
entire region. It will also be heating up again this week with
temperatures approaching 100 degrees lower valleys and 90 degrees in
the Sierra which may result in some density altitude impacts.
-Justin
&&
.REV Watches/Warnings/Advisories...
NV...Dense Smoke Advisory until 5 PM PDT Thursday NVZ003>005.
CA...Dense Smoke Advisory until 5 PM PDT Thursday CAZ071.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Springfield MO
902 PM CDT Wed Jul 31 2024
.KEY MESSAGES...
- A Heat Advisory is in effect for the area through Thursday at
7 PM. Widespread heat index values of 100-110+.
- A weakening cluster of thunderstorms may move into the area
overnight (20-50% chance). A few storms could be severe with
damaging winds. Many areas will remain dry. Additional
thunderstorm chances exist Thursday afternoon (20-40%).
- Heat headlines may need to be extended into the weekend for
portions of southeast Kansas into southern Missouri.
&&
.MESOSCALE...
Issued at 843 PM CDT Wed Jul 31 2024
An area of thunderstorms continued this evening from Iowa down
into northern and central Kansas. This area was on the southern
periphery of a passing shortwave trough across Nebraska. These
storms were beginning to run out of the higher wind fields as
evident by the outflow boundaries beginning to surge out ahead
of the complex. A 30kt low level jet was now in the begnning
phases of organization across western Oklahoma, nosing into the
southwest edge of the thunderstorm complex. Therefore, the big
question is what happens with this activity as it moves
southeast towards the area tonight.
The 00z KSGF sounding measured a very unstable atmosphere with
3390k/kg of mixed layer CAPE however it was capped around 750-800mb
with 52j/kg of CIN (700mb temps were measured at 14C). Also of
note was the ThetaE differential measured at 41C. This is a
pretty high number and indicative of the potential for damaging
winds with any thunderstorms. The warm mid levels/capping
inversion is the main limiting factor for more robust and
widespread storm potential.
Given the presence of a low level jet feeding into the system,
there will remain the potential that this complex survives but
slowly weakens as it approaches the area as it moves into a
stronger capped environment. The last few runs of the HRRR
(including the 00z) have strongly suggested this complex will
begin to weaken as it moves into southeast Kansas and western
Missouri by midnight however often times there remains wind
potential even as the complex is in the weakening phase.
Therefore we have increased precip chances overnight for areas
north of Highway 60. Damaging winds up to 60mph will be possible
with any thunderstorm, otherwise a mostly dry outflow boundary
passage may also contain 40-50mph winds as it moves into the
area.
Overall not a highly confident forecast overnight however areas
especially northwest of Springfield will need to monitor this
complex as it moves in overnight.
&&
.SHORT TERM /THROUGH FRIDAY/...
Issued at 239 PM CDT Wed Jul 31 2024
Current Conditions and Synoptic Overview:
Upper-air analysis reveals a strong short-wave trough centered over
the Dakotas digging into the central U.S. At the surface, a cold
front attached to a surface low by the Nebraska-South Dakota border
drapes south across central Kansas and Nebraska. Southwesterly
surface winds of 10-15 mph continue to advect warm most air over our
area, as the hot and humid airmass expands to the north as a warm
front. As such, temperatures have climbed into the low to mid 90s
under mostly clear skies.
Heat to continue into Thursday:
As has been the focus for the past few days, the primary short-term
hazard continues to be heat. 850mb temperatures this morning
were around the 90th percentile for this time of year,
supporting high temperatures today in the mid to upper 90s.
Combined with continued surface moisture, with dewpoints in the
low to mid 70s, heat indices continue to range between 105 to
110 degrees. Little relief is offered overnight, as lows only
fall to the mid to upper 70s. Thursday decided to copy today`s
homework and pass it off as its own, with very similar highs in
the mid to upper 90s. Continued surface moisture supports the
continuation of muggy conditions, and heat indices from 105 to
110.
An Excessive Heat Warning is in effect for counties north of I-44,
expiring today at 7 pm. A Heat Advisory goes into effect for these
northern counties upon the Excessive Heat Warning`s expiration, and
is currently in effect for all other counties in our CWA until 7 pm
Thursday. As the trough aloft continues to move east, the cold-front
across Nebraska and Kansas will begin to drift southeast, arriving
over southern Missouri Thursday evening. While this should lower
heat indices below heat headline criteria, some heat may linger into
Friday and Saturday in southwestern Missouri and southeastern
Kansas. Thus, some heat headlines may need to be extended in this
region.
Low Precipitation Chances Thursday:
Thermodynamic conditions are favorable for convection in front of the
cold front as it moves to the southeast. Any storms that make it
this far south could take advantage of CAPE values of 2000-2500 J/kg
across southwestern Missouri. However, given the lack of any
mesoscale forcing, most storms are expected to die out before
reaching our CWA, which most CAMS support. Any storms that do reach
this area would do so early Thursday morning, and likely be
weakening. As such, we`ve opted to keep PoPs for our northeastern
CWA below 20%.
Moving into Thursday afternoon, thunderstorm potential is dependent
on convection earlier in the day. The most substantial convective
development is expected to our east, in Illinois and far
southeastern Missouri along outflow from morning convection. Some
CAMs break out isolated development across our north-central CWA,
but confidence in this forecast is low. The Storm Prediction Center
has our eastern CWA in a Marginal Risk for severe weather. Hazards
from these storms include strong wind gusts, locally heavy rainfall,
and lightning.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 239 PM CDT Wed Jul 31 2024
As the shortwave trough moves to the east, our area will sit on the
eastern periphery of a trough over the western U.S. As mentioned
before, the passage of the weak cold front will lead to slightly
cooler temperatures Friday, more so to the north and east (highs in
the low 90s versus the upper 80s). Moving into the weekend,
temperatures warm up a bit, closer to where they were this week in
the mid to upper 90s. Heat headlines may need to be extended into
the weekend into early next week, as heat indices may exceed 105,
although confidence in this forecast is too low at this time. A
signal for cooler temperatures doesn`t occur until midweek next
week, as some shortwave energy moves into the area.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 618 PM CDT Wed Jul 31 2024
VFR conditions should prevail through the TAF period however we
will be watching to the north overnight to see if an area of
showers and thunderstorms can move towards the area. This would
be after 06z. JLN and SGF may see a brief wind shift to the
north with this if it makes it however chances are currently
less than 30 percent. Winds will then turn back southerly for
Thursday with a 30 percent chance for thunderstorms by the end
of the TAF period. Low level wind shear is possible at the sites
overnight however it looks to marginal to include at this time.
&&
.CLIMATE...
Issued at 325 AM CDT Wed Jul 31 2024
Record High Temperatures:
July 31:
KJLN: 104/1980
August 1:
KUNO: 100/2012
August 5:
KSGF: 101/1982
August 6:
KSGF: 102/1956
KJLN: 105/1956
Record High Minimum Temperatures:
July 31:
KSGF: 78/2012
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory until 7 PM CDT Thursday for KSZ073-097-101.
MO...Heat Advisory until 7 PM CDT Thursday for MOZ055>058-066>071-
077>083-088>098-101>106.
&&
$$
MESOSCALE...Burchfield/Schaumann
SHORT TERM...Kenny
LONG TERM...Kenny
AVIATION...Burchfield
CLIMATE...Camden
Area Forecast Discussion
National Weather Service Tulsa OK
833 PM CDT Wed Jul 31 2024
...New SHORT TERM...
.SHORT TERM...
(The rest of tonight)
Issued at 832 PM CDT Wed Jul 31 2024
The expected thunderstorm complex in central Kansas is tracking
well with the latest HRRR run timing- wise, with the intensity of
the complex still expected to decrease as it approaches the
Oklahoma border. The existing low POPs northwest of I-44 after 06Z
appear appropriate to cover the area and extent of whatever
remnants hold together this far south, as do the Sky cover grids.
Above normal low temperatures should still be expected in most
spots, but with temperatures likely to be cooler behind the
outflow boundary from the Kansas complex, will drop lows a couple
of degrees in parts of northeast Oklahoma and into northwest
Arkansas, in line with the HRRR trends. Will also tweak winds to
account for the boundary. Other than those two changes, the rest
of the forecast looks good. Updated forecast will come after 9 pm
to incorporate the expiring heat headlines.
&&
.LONG TERM...
(Tomorrow through Wednesday)
Issued at 219 PM CDT Wed Jul 31 2024
There is a fair amount of spread in short range guidance regarding
the placement of any aforementioned outflow boundary tomorrow
afternoon and resultant maximum heat indices. While drier/ slightly
cooler air behind the boundary will act to reduce heat indices, dew
point pooling just ahead of the boundary may lead to locally
enhanced heat indices. This makes for a more complicated and less
confident forecast considering implications for heat headlines.
That being said, confidence is still high that heat indices will at
least warrant an advisory across the entire area, but a warning is
less certain across northern counties where the boundary would have
the most influence. For now, have kept the northern row of OK
counties capped at advisory level with a cluster of warnings around/
SE of the Tulsa metro area and advisories elsewhere. If storms &
associated outflow are less aggressive tonight and remain in Kansas,
then these northern counties may need to be upgraded to warnings on
future forecasts. Additionally, as has been the case the past few
days, the river valley in AR may climb very close to warning
criteria and this will need to be monitored closely.
The front should push through the FA Thursday night and during the
day Friday... aided by the passage of an upper level trough across
the N Plains into the Great Lakes region. As ridging shifts west
Friday into the weekend, flow aloft becomes more north/northwesterly
with east winds at the surface. This will allow for a subtle
decrease in temperatures over the weekend with highs generally in
the mid-upper 90s and heat indices below advisory levels. However,
southerly winds and upper level ridging are forecast to return to
the region by next week, bringing high temps back into the low 100s
with potential for another round of heat concerns.
Regarding precipitation chances through the period... there will be
a couple opportunities for some rain/ storms through the extended
period, yet the overall forecast remains mostly dry. Did introduce
low PoPs late Thursday evening into Friday in association with the
frontal boundary and an increasing LLJ. This is supported by several
CAMs and HREF probs... generally north of I-40. While isolated
precip cannot be ruled out Friday afternoon near the boundary in SE
OK/ W-Central AR, have opted to keep PoPs below mentionable values
for now until better short-range guidance becomes available.
Additionally, while chances looks slim for our area as of now, a
subtle shortwave embedded in the N/NW flow is projected to move
south through W KS & W OK Saturday into Sunday. Currently believe
any precip will remain restricted to locations west of the CWA, but
it is worth watching. Otherwise, widespread meaningful rainfall
remains elusive.
&&
.AVIATION...
(00Z TAFS)
Issued at 605 PM CDT Wed Jul 31 2024
VFR conditions are expected through the period. Skies will be
mostly clear tonight with southerly wind gusts dying down this
evening. An outflow boundary could approach far northeast
Oklahoma early tomorrow morning with a very low chance (<20%) for
some showers or storms to affect KBVO and provide a brief change
in wind direction. Otherwise, a weak frontal boundary will slowly
drift in NE OK tomorrow afternoon bringing a wind shift to
westerly and then northerly across NE OK and NW AR sites with low
rain chances (~20%) again near the boundary toward the end of this
TAF period.
Bowlan
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 81 101 77 100 / 10 10 20 10
FSM 78 101 78 101 / 0 0 0 10
MLC 78 99 77 101 / 0 0 0 10
BVO 75 100 72 99 / 20 10 20 10
FYV 76 98 71 96 / 0 0 20 10
BYV 75 98 72 95 / 0 10 20 10
MKO 78 100 74 100 / 0 0 20 10
MIO 75 98 72 96 / 10 10 20 10
F10 78 101 72 102 / 0 0 10 10
HHW 74 99 75 102 / 0 0 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory until 9 PM CDT this evening for OKZ049-053-068-069-
071>076.
Heat Advisory from noon to 9 PM CDT Thursday for OKZ049-053>059-
063>065-068-069-072>076.
Excessive Heat Warning until 9 PM CDT this evening for
OKZ054>067-070.
Excessive Heat Warning from noon to 9 PM CDT Thursday for
OKZ060>062-066-067-070-071.
AR...Heat Advisory until 9 PM CDT this evening for ARZ001-002-010-011-
019-020-029.
Heat Advisory from noon to 9 PM CDT Thursday for ARZ001-002-010-
011-019-020-029.
&&
$$
SHORT TERM...22
LONG TERM....43
AVIATION...04
Area Forecast Discussion
National Weather Service Las Vegas NV
1251 PM PDT Wed Jul 31 2024
.SYNOPSIS...Monsoonal moisture will increase across the area
during the second half of the week as a ridge of high pressure
builds over the four corners region. This increase in moisture
will result in scattered showers and thunderstorms developing on
Thursday, which will then continue each day through the weekend.
With the ridge building, temperatures will also increase through
the weekend and remain hot into early next week.
&&
.SHORT TERM...through Friday.
The quiet weather the region has experienced over the past
several days will come to an end on Thursday as the combination of
a building ridge over the four corners region, along with a
disturbance moving across Baja California, will work together to
push monsoonal moisture into the area. Thunderstorm activity on
Thursday will mainly be confined to Mohave, southern Clark, and
San Bernardino counties. However, as the disturbance over the Baja
moves north into southern California, shower and thunderstorm
activity will spread into Inyo County Thursday night and Friday.
WPC has highlighted this area with a marginal risk ERO for Friday.
While most areas will not have issues, the increased dynamics
associated with the disturbance will result in localized areas of
heavy rainfall.
Temperatures tomorrow and Friday will depend on the amount of
cloud cover and ongoing showers/thunderstorm activity. However, a
general increase in readings is expected as the ridge builds over
the area. Smoke from the Nixon Fire near Palm Springs, CA, and the
Boreal Fire in southern Kern County, CA, has decreased. However,
conditions remain favorable, and additional smoke will likely be
generated. The latest HRRR shows that any smoke that is generated
should remain mainly over San Bernardino, Inyo, Nye, and Esmeralda
counties.
.LONG TERM...Saturday through Wednesday.
By Saturday, the better dynamics shift north into the central
Sierra. Scattered showers and thunderstorms will still be possible
over the Sierra and in the Owens Valley, but the threat of
heavier rainfall has diminished. Sunday through Tuesday look more
like our typical monsoon days, with thunderstorms developing over
areas of higher terrain before moving into the valleys later in
the afternoon and evening. Most of the moisture will remain over
Arizona, so the better precipitation chances will remain over
Mohave county.
With the ridge remaining in place, temperatures will remain hot,
with daily maximum readings staying a few degrees above normal.
Heat Risk stays mostly in the `Moderate` category with some spotty
areas of Major and Extreme Heat Risk in Clark, Mohave, Nye, Inyo,
and San Bernardino Counties. However, given the spotty nature of
the high impacts, no heat-related products are expected to be
issued at this time.
&&
.AVIATION...For Harry Reid... Winds will follow typical diurnal
trends today into Thursday, with east to southeast winds
developing by early afternoon and persisting into the evening
before turning southwest after sunset. Speeds will be light,
generally 8kts or less through the TAF period. Smoke from
wildfires burning in Kern County, CA, will move across the valley
through the evening. No reduction in surface visibilities is
expected at the field, but slantwise visibilities may be reduced
to less than 7SM at times, with the most significant impacts
expected along the Baker and Beatty corridors. Otherwise, an
increase in clouds is expected overnight and Thursday morning, but
bases should remain 12kft AGL or higher.
For the rest of southern Nevada, northwest Arizona and southeast
California...Light, diurnally driven winds will continue across
most of the region today and tonight. The exception will be in the
central and northern Owens Valley, including KBIH, where south to
southeast winds gusting to 20 knots can be expected this afternoon
and early evening before decreasing overnight. Smoke from
wildfires burning in Kern County, CA, will continue to affect Inyo
County, with a reduction in slantwise visibilities being the main
impact. Convection in southern Arizona may generate outflow winds
and mid and high-level clouds that could move into the lower
Colorado River Valley (KEED and KIFP) overnight. Otherwise, no
operationally significant cloud cover is expected through the TAF
period.&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
SHORT TERM...Planz
LONG TERM...Pierce/Planz
AVIATION...Planz
For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter