Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/30/24
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
546 PM MDT Mon Jul 29 2024
...New AVIATION...
.SYNOPSIS...
Issued at 205 PM MDT Mon Jul 29 2024
Fewer thunderstorms have impacted northern and central New Mexico
this afternoon, however big impacts have came earlier from the
strong, slow-moving storms over Lincoln county that produced
significant flash flooding downstream from recent wildfire burn
scars. Beyond the south central mountains, isolated to scattered
showers and thunderstorms will be possible over portions of
central to east central and northeastern New Mexico through the
evening. This hit-and-miss shower and thunderstorm activity will
continue into Tuesday and Wednesday over the west central and
southwestern mountains, as well as along and near the central
mountain chain of New Mexico. Temperatures will be hot on both
Tuesday and Wednesday, especially in the eastern plains where many
locations will reach the upper 90`s and low 100`s. Showers and
thunderstorms will begin to increase in northeastern New Mexico on
Thursday as a moist front arrives, and storms will expand to
other areas through the rest of the week as temperatures cool by
just a few degrees.
&&
.SHORT TERM...
(This evening through Tuesday night)
Issued at 205 PM MDT Mon Jul 29 2024
The upper high will remain settled over eastern TX and the ARK-
LA-TX area for tonight into Tuesday with central heights running
around 594-595 decameters at 500 mb. This has started to introduce
a more northward steering flow into NM, albeit very slow in the
places that are actually observing deep, moist convection. Today
that has been the south central and southwestern mountains, and
that will be the focus again on Tuesday. Radar imagery has shown
cells struggling over the Sangre de Cristos with lower PWATs
(closer to 0.67 inch) this afternoon, and this likely will not
increase much going into Tuesday. To get going over the central
valleys or highlands, mesoscale cold pools will have to grow
deeper and carry a ways northward to trigger convection through
the evening, and this would likely be the case again Tuesday
evening. Storms may have better opportunity to develop along a
weak upper level perturbation into the east central and
northeastern plains this evening, as the FV3 model indicates with
subdued support from the HRRR and NAM. With less storm coverage
and less cloud cover, temperatures have risen a few degrees above
normal as geopotential heights have also climbed from a few days
ago. The high temperature forecast on Tuesday does not appear to
warrant any Heat Advisories, but we are close for several central
and eastern zones, particularly in eastern plains zones where the
criteria is 105F.
&&
.LONG TERM...
(Wednesday through Sunday)
Issued at 205 PM MDT Mon Jul 29 2024
The upper high expands over more of the south central and Gulf
Coast states into Wednesday, distributing the deepest moisture
(PWATs of 0.9 to 1.0 inch) over the southern and eastern tiers of
NM while relatively drier air remains entrenched over northwestern
to north central areas. Heights may rise another decameter or two
on Wednesday, continuing to act as a suppressing agent for storms
while temperatures gain another degree or two. Another close call
for Heat Advisories is expected, but as of this time, criteria is
not quite forecast to be met.
On Thursday, the upper high begins relocating northwestward with
heights rising more over NM. However, a difference maker will come
in the form of a moist, backdoor front to northeastern NM which
will send upslope flow to the eastern slopes of the Sangre de
Cristos along with some moisture/surface convergence. This could
lead to an uptick in storms there, putting the HPCC wildfire scar
back into the mix for possible impacts. Most remaining areas of
the forecast area would likely be at a status quo, perhaps gaining
a chance for evening storms developing off of cold pools rolling
off of the Sangre de Cristos. Outflows would likely carry more
moisture westward into Thursday night and Friday morning, setting
the stage for more active and widespread thunderstorms over the
northern and western zones into Friday and Saturday. By Friday
and Saturday, the upper high would be settling over northwestern
CO and vicinity with heights running quite high at 597-598
decameters, but with above average PWATs, temperatures might get
moderated and reduced by a few degrees.
&&
.AVIATION...
(00Z TAFS)
Issued at 538 PM MDT Mon Jul 29 2024
Scattered thunderstorms over wester NM and isolated showers and
storms over central and eastern areas are forecast to gradually
diminish after 30/03Z Tuesday with VFR conditions prevailing
overnight. Wednesday`s round of afternoon showers and storms will
be more limited in coverage, but with greater near surface
moisture moving in overnight from the south, what isolated
thunderstorms do develop will be capable of torrential rainfall,
small hail, gusty and erratic outflow winds and brief MVFR to
possibly IFR conditions.
&&
.FIRE WEATHER...
Issued at 205 PM MDT Mon Jul 29 2024
No critical fire weather concerns are foreseen for the next
several days. The main impacts of concern will be related to heat
and hydrology, or wildfire burn scar flooding. Storm coverage
will remain quite subdued through Wednesday, focusing over the
southwestern mountains where localized heavy downpours will still
be possible under slow-moving cells. Prevailing winds will remain
light to moderate with any concerns about gusty conditions coming
from localized thunderstorm outflows. Some outflows may push
through central gaps and canyons, causing a slightly longer
duration of gusty conditions Thursday night into Friday morning,
as storms will be increasing then. Friday into Saturday and Sunday
are expected to be more active with deeper moisture in place and
more numerous storms.
&&
.PRELIMINARY POINT TEMPS/POPS...
Farmington...................... 61 94 62 97 / 0 0 0 0
Dulce........................... 50 91 51 92 / 5 0 0 10
Cuba............................ 59 90 59 92 / 20 10 20 20
Gallup.......................... 55 91 55 92 / 20 10 10 20
El Morro........................ 55 86 55 86 / 40 20 20 30
Grants.......................... 60 90 60 91 / 40 20 20 20
Quemado......................... 55 87 57 87 / 50 40 30 40
Magdalena....................... 62 87 63 88 / 20 40 20 30
Datil........................... 54 86 56 85 / 40 50 20 40
Reserve......................... 54 91 57 90 / 40 60 20 40
Glenwood........................ 63 94 65 93 / 30 60 20 40
Chama........................... 51 83 51 85 / 10 10 0 20
Los Alamos...................... 65 87 65 88 / 20 20 10 20
Pecos........................... 59 90 60 91 / 10 30 20 30
Cerro/Questa.................... 52 86 52 87 / 20 20 10 20
Red River....................... 42 76 44 77 / 20 30 10 30
Angel Fire...................... 38 81 38 83 / 20 40 20 30
Taos............................ 54 90 53 90 / 20 20 10 20
Mora............................ 54 84 54 86 / 20 40 20 30
Espanola........................ 63 95 62 96 / 10 20 10 10
Santa Fe........................ 64 90 63 91 / 10 20 20 20
Santa Fe Airport................ 62 93 62 94 / 10 10 20 10
Albuquerque Foothills........... 67 93 68 95 / 10 20 20 20
Albuquerque Heights............. 69 95 70 96 / 10 10 20 10
Albuquerque Valley.............. 63 97 63 98 / 10 10 20 10
Albuquerque West Mesa........... 68 96 69 97 / 20 10 20 10
Belen........................... 66 97 66 98 / 20 10 20 10
Bernalillo...................... 67 97 67 98 / 20 10 20 10
Bosque Farms.................... 63 96 63 98 / 10 10 20 10
Corrales........................ 66 97 67 98 / 20 10 20 10
Los Lunas....................... 64 97 64 98 / 10 10 20 10
Placitas........................ 65 94 66 95 / 20 10 20 20
Rio Rancho...................... 68 95 68 96 / 20 10 20 10
Socorro......................... 68 98 69 98 / 30 20 20 20
Sandia Park/Cedar Crest......... 62 89 63 90 / 10 10 20 20
Tijeras......................... 64 91 64 92 / 10 20 20 20
Edgewood........................ 61 91 61 92 / 10 20 20 20
Moriarty/Estancia............... 58 92 58 93 / 10 20 20 20
Clines Corners.................. 60 89 60 90 / 20 20 20 20
Mountainair..................... 61 90 62 90 / 20 20 20 20
Gran Quivira.................... 61 91 61 91 / 20 20 20 30
Carrizozo....................... 67 93 68 94 / 30 30 20 30
Ruidoso......................... 55 85 56 86 / 30 50 20 40
Capulin......................... 57 90 56 90 / 20 20 20 20
Raton........................... 58 94 57 95 / 10 20 20 20
Springer........................ 58 96 57 96 / 10 20 20 20
Las Vegas....................... 58 90 58 90 / 10 20 20 20
Clayton......................... 68 99 68 100 / 20 10 20 10
Roy............................. 63 95 63 95 / 20 10 20 20
Conchas......................... 68 102 69 102 / 20 10 20 10
Santa Rosa...................... 67 97 67 98 / 20 10 20 10
Tucumcari....................... 70 102 71 102 / 20 10 20 10
Clovis.......................... 70 100 71 101 / 10 5 5 10
Portales........................ 69 100 70 101 / 5 5 5 10
Fort Sumner..................... 70 100 70 101 / 10 5 10 10
Roswell......................... 73 103 75 104 / 10 5 10 10
Picacho......................... 67 95 67 96 / 20 30 20 20
Elk............................. 63 91 63 92 / 30 40 20 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 9 PM MDT this evening for NMZ226.
&&
$$
SHORT TERM...52
LONG TERM....52
AVIATION...33
Area Forecast Discussion
National Weather Service Binghamton NY
925 PM EDT Mon Jul 29 2024
.SYNOPSIS...
The weather pattern will be turning more active with warm and
humid conditions through the week. Numerous showers and thunderstorms
are expected Tuesday afternoon into Wednesday, before it dries
out on Thursday. Scattered showers and storms return Friday
into the upcoming weekend with seasonably warm temperatures.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
920 PM Update...
Showers continue to stay east of the region, so PoPs were cut
back from the previous update. Any mention of showers was
eliminated after the next couple of hours. Some additional
minor tweaks were made to temps and dewpts to match obs.
635 PM Update...
Minor tweaks were made throughout the forecast. The first change
was made to the hourly temps and dewpts for the evening hours to
better match the latest observations. Temperatures remain in the
upper 70s to mid 80s. Showers have remained just to the east of
the region. Minor adjustments were made to PoPs to better match
neighboring offices. Thunder also remains in the grids as there
have been some storms this afternoon. Models dry things up late
this evening so may need to pull back PoPs more if that trend
continues. Lastly, more fog was added to the forecast. Model
soundings support fog and low stratus tonight, mainly limited to
the lower elevations.
225 PM Update
Some uncertainty on if/where any isolated showers or t`storms may
pop up this evening. The region will be under a light north-
northwest flow pattern, with MLCAPE perhaps increasing between 500-
1000 J/Kg before sunset. The latest 16/17z HRRR keeps all the
activity out of our forecast area...but the 12z 3km NAM does have a
few slow moving storms firing up across NE PA and Sullivan county
NY. Opted to keep some slight chc pops in the grids for this area,
but current thinking is that the NAM is too high with its forecast
instability. Either way, it will be dry and mild tonight under
mostly clear skies. Lows only dip down into the low to mid-60s.
Tuesday will feature some more active weather for the region,
especially late in the day. The morning looks to start off generally
dry and partly sunny, with some patchy valley fog possible. By
midday and early afternoon the temperatures will really heat up
under the steady southerly flow (7-15 mph sfc winds). The warmest
locations will be from Ithaca, north toward Auburn, Syracuse and the
Mohawk Valley. These areas are forecast to remain mostly sunny
longer and heat up in a downsloping southerly flow. Highs in this
region will be in the upper 80s to lower 90s, and when combined with
sfc dew points in the upper 60s to low 70s max heat indices could
reach the mid-90s in the lower elevations. Will hold off on any heat
advisories at this time due to uncertainty in cloud cover and
t`storm arrival times...by late afternoon temperatures look to level
off or even fall several degrees as clouds and outflow develop.
The rest of the CWA will see highs in the low to upper 80s.
Scattered thunderstorms are forecast to start popping up by
early afternoon, then increase in coverage by late afternoon and
evening as a low pressure system passes by to our north. MLCAPE
will be between 400-800 J/kg, but pwats look to approach 2.00
inches, especially over NE PA and the NY Southern Tier heading
into the evening hours. Some of the storms could produce heavy,
excessive rainfall. WPC has this area highlighted in a slight
risk for excessive rainfall that could lead to isolated flash
flooding concerns.
The showers and storms lingering well into Tuesday night as a series
of surface lows and/or perhaps come MCS develop occurs over the
region. Therefore, have categorical PoPs in the forecast, with
another 0.25-0.75 inches of areal average rainfall expected; and
localized higher amounts certainly possible. Very humid and muggy
with lows in the mid-60s to lower 70s.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Showers and thunderstorms are expected Wednesday as a surface
cold front and upper level shortwave move from west to east
across the area. However, there is some uncertainty as to how
active and widespread showers and storms will be over the area
as the Euro is more progressive with these features, clearing
the front and shortwave out and to the east faster than the GFS
which has a second wave of energy moving along the shortwave.
There is the potential for locally heavy rainfall Wednesday,
especially if any showers and storms train over the same areas
as PWATs on the Euro are generally 1.00-1.50" while the GFS tops
out between 1.50-2.00" with the Canadian falling in between.
While there is generally 500-1000 J/kg of CAPE between the
models, shear is pretty low between 15-20 knots so the risk for
severe storms seems low. Wednesday`s high temperatures will be
tricky given the clouds and convection, but are expected to
range from the upper 70s to the mid 80s.
Drier conditions do look to move in Wednesday night, especially
for the overnight hours and the short-lived break in convection
is expected to carry over into Thursday and Thursday night.
With weak ridging aloft, it does turn warmer again on Thursday
as highs are expected to be from the mid 80s to lower 90s in
some valley locations.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
The chance for showers and thunderstorms returns Friday into
Saturday as the next organized feature moves in. With PWATs
projected to be above 1.50" each day, localized heavy downpours
will be possible. There`s some question as to how much
precipitation may linger into Sunday but then there appears to
be another brief lull in precipitation that tries to move in on
Monday before at least a small chance in showers and storms
returns heading into the middle of next week.
High temperatures Friday are expected to remain in the mid 80s
to low 90s as showers and storms may hold off until the
afternoon or evening. Saturday through early next week look to
be from the upper 70s to mid 80s. Overnight lows look mild in
the 60s through Saturday night.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR conditions across all terminals expected to remain through
the bulk of the period. There is a chance for MVFR ceilings to
develop at AVP tomorrow morning, but left it as a scattered deck
for now and will refine with 6Z TAFs. Scattered showers and
thunderstorms are expected to develop late tomorrow
afternoon/evening, but confidence and timing of showers and
storms over any one location is too low at this time to add to
the forecast.
Tuesday night through Wednesday...Scattered showers and
thunderstorms and associated restrictions possible.
Thursday...Mainly VFR expected
Friday & Saturday...Scattered showers and t`storms return with
possible restrictions.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MJM
NEAR TERM...BTL/MJM
SHORT TERM...DK
LONG TERM...DK
AVIATION...MPK
Area Forecast Discussion
National Weather Service Bismarck ND
1025 PM CDT Mon Jul 29 2024
.KEY MESSAGES...
- Isolated to scattered severe thunderstorms are possible this
evening, mainly across south central North Dakota into the
James River valley. The main expected hazard is damaging
winds up to 70 mph.
- Isolated to scattered severe thunderstorms will be possible
Tuesday afternoon through the early overnight period, mainly
across central North Dakota. Potential hazards include large
hail up to golf balls in size, and wind up to 60 mph.
- Isolated severe thunderstorms are also possible Wednesday,
primarily across central and eastern North Dakota.
- Above normal temperatures are in the forecast through the work
week, with several days of highs in the 90s.
&&
.UPDATE...
Issued at 1024 PM CDT Mon Jul 29 2024
Quick update to 1) remove McHenry, McLean, and Sioux Counties
from the Severe Thunderstorm Watch and 2) amend PoPs to account
for the isolated thunderstorms over Mercer and Oliver Counties.
UPDATE
Issued at 952 PM CDT Mon Jul 29 2024
** MESOSCALE DISCUSSION **
The small, but increasingly-organized MCS moving across south
central ND is expected to continue its forward propagation and
maintenance with damaging wind gusts of 60 to around 70 mph,
before exiting Dickey, LaMoure, and Stutsman Counties by around
1130 pm CDT. The environment downstream of the linear complex of
storms remains characterized by MLCAPE up to 3000 J/kg, with
surface dewpoints in the lower 70s F. While CIN is increasing
for boundary-layer based parcels (which led to the demise of the
earlier, MCS-preceding supercells), the cold pool with the MCS
is expected to be deep enough for forced ascent to maintain its
strength the next few hours. Low-level easterly flow and deep-
layer westerly flow aloft further favors cold pool maintenance
and related damaging wind gust potential. The Aberdeen VWP does
suggest 0-3-km bulk shear gradually increasing and reaching 30
kt, so gusts up to 70 mph are possible given DCAPE also in the
1000-1500 J/kg range.
Otherwise, a few updrafts have developed upwind of the MCS, in
particular in the Beulah/Hazen areas as of 0245 UTC. There is
uncertainty in what is causing this convection in the wake of
the earlier storms, though a weak low-level jet (marked by 25
kt southerly flow at 850 mb) atop the cold pool from that
earlier convection may be responsible. Sufficient elevated CAPE
and shear exists to result in a low severe-storm risk with this
activity. However, given the nebulous forcing and elevated
nature of these updrafts, the overall potential will likely be
minimized.
CJS
UPDATE
Issued at 904 PM CDT Mon Jul 29 2024
The Severe Thunderstorm Watch has been cancelled for Ward, Dunn,
Stark, Hettinger, Adams, Mercer, and Grant Counties. The
continued risk for severe weather is now mainly east of the
Missouri River.
UPDATE
Issued at 754 PM CDT Mon Jul 29 2024
** MESOSCALE DISCUSSION **
A few supercells with large to very large hail and damaging
winds of 60-70 mph will persist until 9-10 pm CDT, before they
weaken. However, the line of storms approaching the Missouri
River in south central ND as of 745 pm CDT will continue to the
east with a risk of damaging winds (potential gusts of 60 to 70
mph). That line will likely continue eastward through south
central and into southeastern ND and the James River valley
through 11 pm CDT.
The 00 UTC Aberdeen, SD RAOB sampled the supercell-favorable
near-storm environment in south central and southeastern ND,
with nearly 40 kt of effective-layer shear and MLCAPE of
2000-3000 J/kg. The subtle warm nose on the sounding suggests
that once the boundary layer begins to cool toward sunset the
discrete supercells will begin to weaken, although sustained
intense mesocyclones may maintain their strength a bit longer
than thermodynamics alone may suggest. Until that weakening
occurs, the setting will continue to favor large to very large
hail up to around 2 inches in diameter with discrete supercells.
Meanwhile, the linear structure of storms organizing in south
central ND as of mid evening will likely develop a sufficient
cold pool and associated forced ascent to maintain an eastward
propagation eastward through all of south central and into
southeastern ND. Recent HRRR simulations support this as well,
with extrapolation and HRRR forecasts having the line reaching
Dickey and LaMoure Counties in the 10 to 11 pm CDT timeframe.
DCAPE on the order of 1000-1500 J/kg and 0-3-km bulk shear of
20-25 kt suggests a damaging wind-gust risk with this line.
Finally, satellite imagery shows some agitated cumulus in Dunn,
Stark, and Hettinger Counties, ahead of the primary surface
wind shift, which remains in that area. The boundary layer is
likely stabilized with significant CIN in those counties behind
the earlier storms, but given the satellite presentation and
surface dewpoints near 60 F remaining ahead of the wind shift,
we are maintaining the Severe Thunderstorm Watch in that area
for now. That residual risk will likely diminish by around 9 pm
CDT/8 pm MDT as the boundary layer further cools with sunset.
CJS
UPDATE
Issued at 507 PM CDT Mon Jul 29 2024
** MESOSCALE DISCUSSION **
Scattered severe thunderstorms including supercells with large
hail up to around 2 inches in diameter and damaging winds of 60
to 70 mph are expected the next few hours.
As of late afternoon, a cluster of supercells near the west end
of Lake Sakakawea formed near a differential mixing boundary and
related subtle wind shift, and a low-level thermal ridge axis
with surface temperatures near 90 F. An additional supercell is
just northwest of Bismarck as of 22 UTC, and while that storm is
not explicitly tied to any low-level convergence, it`s located
within an environment of minimized CIN and maximized bouyancy
thanks to surface dewpoints in the middle/upper 60s F. Finally,
additional, high-based convection in southwestern ND also formed
in an area where surface temperatures exceeded 90 F and along a
surface wind shift. This convection is expected to intensify as
it moves into south central ND where surface dewpoints and thus
MLCAPE increase further.
VWP and model-derived soundings reveal 30 to 40 kt of deep-layer
shear, with largely straight hodographs that favor splitting
supercells with large hail up to around 2 inches in diameter.
The structure of hodographs suggests that both left- moving and
right-moving supercells may be equally favored, and they will
have much different motions following splits. Right-moving
supercells will move easterly around 20 kt, while any left-
splitting supercells will move north-northeast at closer to 30
kt.
Given the ongoing supercells and expected intensification of the
storms moving out of southwestern and into south central ND, we
expect scattered supercells across central ND the next several
hours. Eventually storm collisions from splits and cold pool
expansion may result in upscale growth further into the evening,
which could transition toward more wind-related hazards in a few
hours. Prior to any upscale growth, large DCAPE in excess of
1000 J/kg still suggests supercells will have some damaging wind
gusts of 60 to 70 mph at times.
Lastly, given recent radar trends, expectation of splitting
supercells, and downstream dewpoints in north central ND in the
lower 60s F, we did expand the Severe Thunderstorm Watch into
Ward and McHenry Counties.
CJS
UPDATE
Issued at 438 PM CDT Mon Jul 29 2024
Quick update for the issuance of a Severe Thunderstorms Watch
for south central and much of southwest North Dakota, in effect
until midnight CDT.
&&
.DISCUSSION...
Issued at 230 PM CDT Mon Jul 29 2024
Today, broad southwesterly flow continues over the northern
Plains. Temperatures today will be slightly warmer than
yesterday, with highs this afternoon expected to be from the
lower 80s northeast to the lower 90s southwest. With surface
high pressure exiting to the east, winds are light from around 8
to 12 MPH this afternoon. Winds will generally diminish and
turn southerly through this evening. The main show today is the
potential for isolated to scattered severe thunderstorms this
afternoon and evening as a modest mid-level shortwave traverses
across the northern Plains. SPC has placed portions of
southwestern and the southern two thirds of central North Dakota
in Slight risk (level 2 of 5) for today, with hatched 15% areas
for significant hail and wind over much of this same area. The
rest of central North Dakota has also been placed in a Marginal
risk (1 of 5) as well. Increased flow in the mid levels will
promote higher shear values across much of the forecast area
than have been observed over than past few days, with model bulk
shear in the 35-45 knots range broadly in central North Dakota
this afternoon. The higher surface temperatures and increase
moisture returns into our area will promote dewpoints
approaching the mid 60s across central North Dakota this
afternoon. As such, the 12Z HREF model MUCAPE values approach
the 1500-2500 J/KG range this afternoon. Questions remain as to
what storm mode will be favored this afternoon, and how it will
transition through the early evening period without a well-
defined surface boundary. With the axis of instability being
orientated in a north-south manner this afternoon, that is,
perpendicular to the direction of the shear, our current
expectations that convection will begin as discrete
cells/supercellular which, with the steep mid level lapse rates
and model hodographs fairly straight, could promote large hail
approaching 2 inches in diameter. Later in the afternoon, CAMs
have picked up on a transition into a more clustered/linear mode
as the axis of instability beings to become more
southwest/northeasterly in orientation. As such, the expectation
is that the hail threat will begin to diminish at the time of
this transition, which strong winds will instead take center
stage. With DCAPE values approaching 1000 J/KG and a well mix
boundary layer early this evening, wind gusts could approach 70
MPH. These anticipated hazards, hail up to 2 inches and wind
gusts up to 70 MPH, are mainly for the south central portion of
the state, while any storms that do develop over the north
central would instead see hazards with hail up to quarters in
size and winds up to 60 MPH. Our current expectations for timing
would be from around 4 PM to 11 PM CDT, as strong capping is
anticipated to develop fairly quickly after sundown tonight.
Warmer conditions will be found again on Tuesday as a minor
shortwave ridging traverses through the northern Plains, with
highs forecast from around 90 in the northeast to the upper 90s
in the southwest. Another shortwave trough is anticipated to
approach the forecast area from the west Tuesday afternoon, with
an attendant surface low system passing through Montana and
into western South Dakota. With south-southeasterly flow
promoting abundant moisture returns at the surface, dewpoints
across much central North Dakota approach the mid 60s to lower
70s range. With model MUCAPE values falling in to a the
2500-3000 J/KG range at this time, the question remains as to
how well this will align with the available shear Tuesday
afternoon. Models remain somewhat dispirit as to where the axis
of higher shear from the interaction from zonal flow aloft and
southeasterly flow at the surface will setup, but most have at
least 30-35 knots available across much of central North Dakota.
As such, we have begun to advertise large hail up to golf balls
in size, and winds up to 60 MPH. The timing for this event will
be somewhat similar to today if lasting a little longer, so for
now have begun to advertise from around 4 PM CDT to 1 AM CDT.
SPC have place much of central North Dakota under a Slight risk
(level 2 of 5) for scattered severe thunderstorms on Tuesday,
with a Marginal risk (level 1 of 5) over portions of western
North Dakota and the southeastern James River Valley. Otherwise,
due to prevailing smoke aloft from the wildfires in the Pacific
northwest, have left cloud cover at a minimum of 30% through
midnight on Wednesday. With the return of more zonal flow
Wednesday, the HRRR has begun to let the vertically integrated
smoke to begin diminishing in the northwest, but we will have to
continue to monitoring this trend.
By Wednesday, flow aloft has become much more zonal, promoting
somewhat cooler high temperatures broadly in the 80s across
western and central North Dakota. Another shortwave will push
across the northern Plains on Wednesday, with sufficient
instability and shear for severe weather in the afternoon and
early evening hours over the James River Valley. However, the
better environment continues to be progged further to our south
and east, and any strong to severe storms that do develop in our
forecast area Wednesday afternoon is currently favored to move
quickly out to our east. As it stands, the SPC has place much of
southcentral North Dakota into a Marginal risk (level 1 of 5)
for isolated severe thunderstorms on Wednesday.
In the later half of the week, the aggressive buildup of the
ridge up and over the northern Plains will promote a return of
warm and dry conditions across the forecast through early next
weekend. Highs are forecast to be generally in the mid to upper
80s north to mid to upper 90s south, with portions of the
southwest potentially reaching into the lower 100s on Friday.
High temperatures are then anticipated to begin to trend down
through the weekend and into early next week as the ridge begins
to squash down as a northern Pacific upper level trough beings
to make landfall in northern British Columbia. This flattening
of the ridge may also invite the next chances for precipitation
across the forecast if some sort of ridge rider develops.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1024 PM CDT Mon Jul 29 2024
The risk of severe thunderstorms has ended for areas north and
west of KJMS. Sub-severe storms could still impact KBIS and KJMS
into the early overnight hours. Another round of strong to
severe storms is then possible Tuesday afternoon and evening.
Outside of storms, VFR conditions are expected through the
forecast period. Light southerly winds will turn westerly in
western North Dakota on Tuesday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...CJS/Hollan
DISCUSSION...Adam
AVIATION...Hollan
Area Forecast Discussion
National Weather Service Cheyenne WY
759 PM MDT Mon Jul 29 2024
.KEY MESSAGES...
- Critical to near-critical fire weather conditions are expected
on Monday and Tuesday. Red Flag Warnings and Fire Weather
Watches are in effect.
- Mainly dry air aloft will continue overhead midweek, limiting
shower and thunderstorm chances and producing a mainly hot
and dry workweek.
- Atmospheric moisture will increase slightly for Friday and
Saturday, with a corresponding increase in late day shower and
thunderstorm coverage.
&&
.UPDATE...
Issued at 757 PM MDT Mon Jul 29 2024
Decided to allow current Red Flag Warning to expire on time at 8
PM this evening. Winds easing this evening at most locations.
Looking at GFS winds tomorrow...looks like winds will be
stronger and more widespread. Went ahead and upgraded the Fire
Weather Watches to Red Flag Warnings for Tuesday. Updates sent.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 242 PM MDT Mon Jul 29 2024
Latest GOES WV imagery shows a large swath of dry air extending
from central CA northeast towards our area. This is
contributing to critical fire weather conditions across much of
south-central WY today with gusty southwest winds around 25-30
mph. This will continue through much of the afternoon with weak
shortwaves passing in the flow contributing to enhanced flow
aloft along with deep mixed layers. Red Flag Warnings continue
through early this evening, but poor recoveries are expected
overnight (~25-30%) ahead of yet another hot, dry day Tuesday.
With a strong mslp gradient developing along the Laramie Range
behind these disturbances, dry downsloping winds could keep
critical fire weather conditions around for select areas through
tonight. Did consider extending the Red Flag Warning through
the night for the South Laramie Range, but still have
uncertainty with how persistent these conditions would be
overnight. Regardless, Fire Weather Watches are in effect again
Tuesday afternoon with widespread single digit RHs. HDWI shows
numerous GEFS members climbing above the 95th percentile Tuesday
for much of south-central and east-central WY where headlines
are currently posted as the dry upper level pattern persists
another day with gusty winds. Tuesday afternoon temperatures
will climb above the mid-90s east of the Laramie Range and
triple digits across much of the NE panhandle.
Only other forecast concern in the short term will be in the next 1-
2 hours with isolated showers and thunderstorms over portions of the
NE panhandle. Previous guidance has kept much of this activity well
off to the east of the CWA, but latest satellite and surface
observations suggest the dryline has not pushed far enough east just
yet. Ongoing development over Morrill and Cheyenne Co could result
in a strong storm to develop with ~500-800 J/kg of MLCAPE and strong
mid-to-upper level flow that would enhance shear profiles. Latest
HRRR and NAMNest have been resolving this trend, but pushes storms
east of the CWA into central NE by 00z tonight.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 242 PM MDT Mon Jul 29 2024
Overall, looking at a quiet long term forecast as the CWA sits under
the influence of an upper-level ridge. The "coolest" day of the long
term will be Wednesday, as a shortwave crosses Wyoming. This
shortwave is relatively moisture starved, especially across Wyoming
where the mid-levels will continue to remain quite dry. The biggest
impact with this shortwave will be the brief reprieve of 100 degree
temperatures across the CWA`s eastern zones. Temperatures will be
about 5 to 10 degrees cooler than Tuesday, with highs in the 80s and
90s. Strong ridging will build over the Rockies into the end of the
week, leading to a prolonged period of hot temperatures. High
temperatures Thursday through Sunday will be above average as 700 mb
temperatures hang in the +14C to +20C range. NAEFS indicates these
temperatures to be roughly in the 90th percentile of climatology. As
a result, highs will likely be in the mid to upper 90s for most
areas east of the Laramie Range, with perhaps a few 100s sprinkled
in there. For areas to the west, upper 80s and low 90s are possible.
Precipitation chances during this time will remain minimal. Cannot
rule out a few high terrain storms developing and moving into the
plains Friday, Saturday, and Sunday afternoon. During this time a
few upper-level disturbances will traverse the ridge, slightly
increasing precipitation chances.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 513 PM MDT Mon Jul 29 2024
VFR conditions across all of southeast Wyoming and western
Nebraska for the 00Z TAF period. Gusty winds will decrease over
the next few hours, before increasing again tomorrow afternoon.
With fires in northern Colorado, KAIA and KSNY may see slight
visibility reductions from smoke and haze. Have both terminals
at 6SM for a few hours overnight tonight. May see haze and smoke
continue through tomorrow afternoon.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning until 8 PM MDT this evening for WYZ418>421-
423-425-427>429-432.
Red Flag Warning from noon to 8 PM MDT Tuesday for WYZ417>421-
423-425-427>430-432.
NE...None.
&&
$$
UPDATE...GCC
SHORT TERM...MB
LONG TERM...SF
AVIATION...AM
Area Forecast Discussion
National Weather Service Hastings NE
927 PM CDT Mon Jul 29 2024
...Short Term and Key Messages Update...
.KEY MESSAGES...
- Hot temperatures and heat index values will be a concern through
Wednesday.
- A Heat Advisory is in effect for the majority of our coverage
area Tuesday afternoon-early evening, and if current forecast
trends hold, several counties may need extended into Wednesday
as well.
- An Excessive Heat Warning is in effect for Tuesday and
Wednesday for portions of north central Kansas and south
central Nebraska (southeast of the Tri Cities).
- Strong to severe storms are possible each late afternoon
and/or evening through Wednesday. The main threats include
quarter size hail and winds up to 60 mph.
&&
.UPDATE...
Issued at 927 PM CDT Mon Jul 29 2024
-- A few notes/comments regarding recent forecast updates for
both overnight thunderstorm potential and some additional heat-
related info added into our Excessive Heat Warning/Advisory
statements (NPWGID) and also Hazardous Weather Outlook
(HWOGID):
1) Overnight thunderstorm potential:
As of this writing, all ongoing strong to severe storm activity
is "safely" north of our coverage area (CWA)...mainly up within
25 miles of the NE/SD border.
As the night wears on, and leaning heavily on latest higher-res
solutions from HRRR/NAMNest, it looks quite likely that the vast
majority of thunderstorm potential will continue to focus at
least 25-50 miles north-through northeast of our CWA within
northern Nebraska, with activity likely to really struggle to
develop southward into our CWA where weaker upper forcing and
notably-warm mid level temps (14-16C at 700 millibars) should
keep capping fairly strong. Although surprises are always
possible, this forecaster doesn`t necessarily agree with SPC
dropping the Slight Risk (level 2 of 5) southward into our far
northern counties on their latest Day 1 outlook for the
overnight hours. That being said, we have maintained a small
stripe of slight (20%) thunderstorm chances across some of our
far north-northeast counties overnight, just in case some rogue
activity can develop that far south (while also maintaining
low-confidence severe potential in our HWO).
Have also introduced slight chances for a few showers/weaker
storms into a few west-central counties (such as Dawson/Buffalo)
for very late tonight (mainly after 4 AM), per last few HRRR
runs suggesting some elevated development...possibly along
outflow from northern Neb convection.
2) Tuesday-Wednesday heat-related products/messaging:
- First off, the Heat Advisory for today has been allowed to
expire for Jewell/Osborne/Mitchell counties in KS.
- Looking ahead: Have made no area/timing modifications to
earlier-issued Heat Advisory/Excessive heat Warnings for
Tuesday and/or Wednesday. However, did add an "Additional
Details" bullet to the Tuesday Heat Advisory to fully
acknowledge that several counties might (probably will?) need
the Advisory extended into Wednesday as well. Will defer to
next few shifts to potentially make this move.
&&
.DISCUSSION...
Issued at 247 PM CDT Mon Jul 29 2024
Today and tonight...
An upper ridge is centered over Texas and covers most of the
southern half of the country. An upper trough is over the Pacific
Northwest with another upper trough extending from the Midwest to
the East Coast. Winds are mostly light across south central and
central Nebraska and north central Kansas with temperatures in the
80s and 90s. High temperatures today will generally range from the
lower 90s to around 104 degrees with heat index values in the mid
90s to around 108 degrees. A Heat Advisory is in effect for today
for portions of north central Kansas. Showers and thunderstorms are
possible across the area this afternoon into tonight but chances are
low (15% to around 25%). Any storm that does develop and move across
the area may become strong to severe due to high instability and
fairly high wind shear. Hail up to the size of quarters and wind
gusts up to 60 mph will be the main threats. If an upper
disturbance/shortwave moves over the area, this will likely initiate
storm development. The areas with the greatest chance of having
storms will generally be north and east of the Nebraska Tri-Cities
area with the most likely time of occurrence being later this
evening. Light winds are expected tonight with lows in the mid 60s
to mid 70s.
Tuesday through Wednesday night...
The upper ridge builds slightly further north on Tuesday. Winds will
increase a little out of the south from those today with gusts of
around 15 to 20 mph during the afternoon. Mostly sunny skies will be
present on Tuesday with highs in the mid 90s to over 105 degrees.
Heat index values are expected to range from near 100 degrees to
just over 110 degrees. Dewpoints in the 60s and 70s will contribute
to the high heat index values. An Excessive Heat Warning is in
effect for portions of north central Kansas and south central
Nebraska Tuesday through Wednesday. A Heat Advisory is in effect for
the rest of our forecast area on Tuesday. The high moisture and heat
will lead to very unstable conditions across the area. Wind shear
will also be fairly high so if an upper disturbance moves over the
area, then strong to severe storms may develop. The best chance for
storms will be the late afternoon into the overnight hours but
chances will be low (15% to around 20%). Overnight lows will
continue to warm with temperatures in the mid 60s to upper 70s
Tuesday night.
The upper ridge over Nebraska and Kansas becomes flattened on
Wednesday as an upper trough moves over the northern Plains. Upper
level disturbances will move over the area with low (15% to around
25%) chances of showers and thunderstorms during the day. Fairly
high CAPE, wind shear, and mid-level lapse rates will be present so
any storm that develops will have the potential to become strong to
severe. Chances of showers and storms increase (up to around 35%)
Wednesday evening in advance of a weak cold front moving into the
area. High temperatures on Wednesday will be slightly cooler than
the previous day. Heat index values on Wednesday are expected to
range from the mid 90s to around 110 degrees. The weak cold front
will continue to move through the area Wednesday night with
temperatures cooling into the mid 60s to lower 70s.
Thursday through Sunday night...
An upper trough will be centered over Minnesota and Iowa on Thursday
with northeasterly winds across south central and central Nebraska
and north central Kansas. High temperatures on Thursday will be
cooler than the previous day with highs ranging from the lower 90s
to upper 90s. Heat index values on Thursday will generally range
from the mid 90s to around 100 degrees. An upper level disturbance
is expected to move across the area so showers and thunderstorms
will again be possible (around 15% chance). The most likely area for
storm development will be in north central Kansas closer to the
front. Low temperatures Thursday night will be similar or slightly
cooler than the previous night. An upper ridge will be over most of
the western half of the country on Friday with Nebraska and Kansas
on the eastern edge of the ridge. High temperatures on Friday will
be similar or slightly warmer than the previous day. Low
temperatures Friday night and Saturday night will mostly be in the
60s then will warm up some Sunday night with lows in the mid 60s to
lower 70s. High temperatures Saturday and Sunday will generally
range from the lower 90s to around 100 degrees.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 649 PM CDT Mon Jul 29 2024
For KGRI/KEAR Airports:
VFR conditions are expected through the next 24 hours. Winds
will continue to tick down overnight turning towards the SE. A
few clods may be introduced Tuesday morning with winds peaking
in the daytime around 10-12 knots and turning towards the
south.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory from noon to 8 PM CDT Tuesday for NEZ039>041-
046>049-060>064-072>077-082>085.
Excessive Heat Warning from noon Tuesday to 8 PM CDT Wednesday
for NEZ086-087.
KS...Heat Advisory from noon to 8 PM CDT Tuesday for KSZ005-006-017.
Excessive Heat Warning from noon Tuesday to 8 PM CDT Wednesday
for KSZ007-018-019.
&&
$$
UPDATE...Pfannkuch
DISCUSSION...Schuldt
AVIATION...Stump
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1004 PM EDT Mon Jul 29 2024
.SYNOPSIS...
The weather pattern remains active through the middle of the week
with numerous mainly afternoon and evening showers and
thunderstorms. The hot upper level ridge to our west influences
our weather late in the week with well above normal temperatures.
A cold front will approach from the northwest during the weekend but
may not reach our area as hot weather continues.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 940 PM EDT Monday: Conditions have quieted down across the
forecast area with patchy mid and high clouds left in the wake
of earlier convection. Now eyes turn to our NW, where severe
thunderstorms are beginning to develop across south-central
IL. It seems most of the guidance is initializing this activity
too far east. The more westward initiation along with some
overturning from an earlier MCS that tracked thru central TN
makes for a low-confidence forecast on what a potential MCS will do
overnight. There is still 2000-3000 J/kg of MUCAPE across much of KY
and western TN. So if storms invof Cincinnati get organized, they
could make a run for the NC mountains before daybreak Tuesday. So
with that said, will keep a chc PoP in there across the TN border
late tonight. Whatever convection does reach the CWFA, the arrival
around diurnal minimum heating and marginal bulk shear should cause
it to weaken quickly and struggle to cross the mountains. Otherwise,
expect areas of low stratus and patchy fog to develop with lows
near to slightly above climo.
The latest CAMs still show an MCS making a run for the forecast
area overnight before pushing into the western Carolinas around
daybreak on Tuesday. The CAMs show this system gradually falling
apart as it crosses the southern Appalachians so have the highest
PoPs (likely) confined along the NC/TN border with lower PoPs
elsewhere. The SPC Day 2 Severe Weather Outlook has the entire
area in another Marginal risk for isolated severe storms on
Tuesday. However, this looks to be mainly for the early morning
activity associated with the MCS. Confidence on the severe weather
potential early Tuesday morning remains low as the system will
not have peak daytime heating to work with and is expected to
gradually weaken as it pushes farther into the CWA. CAMs show
very little redevelopment of convection behind this system
Tuesday afternoon/evening so capped PoPs to chance during this
timeframe. The HRRR has scattered convection developing across
the SW NC mountains and northeast Georgia Tuesday afternoon but
the NAMNest shows mostly dry conditions in these areas. Both the
HRRR and NAMNest show isolated activity developing east of the
mountains Tuesday afternoon but they are not in agreement on the
exact placement of convection. Thus, confidence on PoPs will be
low after Tuesday morning. Highs on Tuesday may finally climb to
a few degrees above normal, with the southern half of the area
potentially seeing temps climb back into the lower 90s. However,
debris cloud cover and residual cold pool from the decaying MCS
may limit high temps on Tuesday.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 215 PM EDT Monday: Not a lot of change to earlier thinking
for the middle part of the week. Two main concerns continue. First
will be the potential for MCS-related activity given the favorable
ridge-trof alignment and NW flow aloft that will allow convective
systems forming over the Midwest to roll downhill toward the
mtns. Some of the model guidance continues to show the potential
for an MCS developing over the Midwest and making a run toward
the NC mtns Tuesday night, altho the CAMs are less active in that
regard. The more interesting day might be Wednesday, with a more
favorable timing shown for an upstream MCS approaching late in the
day and reaching the mtns early enough with sufficient instability
(sfc-based CAPE in the 2000-3000 J/kg range) east of the mtns to
allow for a "crosser", in other words, an MCS that makes it over
the mtns unscathed. If that happens, we would have a wind damage
threat in the late afternoon/evening across the fcst area. Precip
probs favor a high chance/likely over the mtns, but will be kept
low over the eastern zones. The situation gets less favorable for
an MCS by Thursday as the upper ridge builds in from the lower MS
Valley region and nudges the MCS track to the N/NE. Which brings
us to the second concern, that being the heat. Altho high temps
have crept down a degree or two for Thursday afternoon, the dewpt
remains high enough to result in triple digit heat index east
of the mtns and plenty of spots around 105. There`s still a lot
that can go wrong with this plan if we have too much convection
around in the afternoon, but we will soon start mentioning the
heat potential in the HWO given the recent model consistency.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 1215 PM EDT Monday: Confidence is slowly growing that we will
have heat-related problems persisting across the region through
Friday, even as the upper ridge breaks down during the day, but not
fast enough to keep temps from climbing well up into the 90s. The
heat index may reach triple digits just about everywhere outside
the mtns in the afternoon, and areas along/south/east of I-85 may
get to 105 or higher, so signs are pointing toward needing a Heat
Advisory late in the week. Models are becoming more consistent
with closing off an upper low over the Midwest/Great Lakes region
beginning on Friday, moving it slowly east on Saturday, and then
opening up/lifting out to the north on Sunday. This could push
a frontal boundary across the region from the NW on Saturday and
possibly stall it nearby on Sunday, so expect above climo precip
probs both days and temps dropping back a bit toward normal,
but still warm. Whether or not this ends up with any severe
storm or flash flooding threat is uncertain. Which brings us
to Monday. By now, readers that like to skip ahead to the last
chapter will have already noticed how some of the model guidance
suggests a low pressure center of tropical origin affecting parts
of the Southeast early next week. All bets are off at this point,
and we will be anticipating some changes along the way, but will
be keeping an eye on the potential while keeping expectations in
check. So, we keep Monday close to climo for now.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Thunderstorms are expected to east of KCLT to
start the 00z TAF, with some lingering SHRA around for the first
couple hours of the TAF. Overall, convection should wane this
evening, leaving mostly clear skies. Guidance generally agrees on
low CIGS and possibly some fog forming across the area late tonight
thru daybreak Tuesday. This seems most likely in the mountain
valleys and the NC Piedmont, with more question as to how much
forms across the northern and eastern Upstate. A lot of uncertainty
on timing and chances of convection Tuesday, as a complex may drop
south out of the Ohio Valley and push into the NC mountains in the
morning, likely dissipating before reaching the Piedmont. But some
guidance slows it down, and has a new round of storms form along the
outflow during the typical mid-aftn thru early evening hours. Either
situation is plausible, so will have an earlier TEMPO for TSRA at
KAVL, while sticking to more typical timing for the other sites.
Should see VFR return across the rest of the terminals by late
Tuesday morning or early Tuesday afternoon. Winds will generally
be SW/WSW east of the mountains through the period. Winds across
the mountains should be mainly NW/WNW.
Outlook: Daily shower and thunderstorm chances will continue
through the rest of the week, with the mountains having the best
chance for activity. Fog/low stratus will be possible each morning,
especially in the mountain valleys and over areas that received
heavy rain the previous day.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...AR/ARK
SHORT TERM...PM
LONG TERM...PM
AVIATION...ARK
Area Forecast Discussion...UPDATED
National Weather Service Indianapolis IN
941 PM EDT Mon Jul 29 2024
.KEY MESSAGES...
- Thunderstorms, possibly Severe, expected late this afternoon and
this evening.
- Thunderstorms may produce very heavy rain
- Morning fog possible
- Dry and Hot on Tuesday
- Daily storm chances continue through Friday, severe weather and
localized flooding concerns possible each day.
- Heat indices near or above 100 degrees possible Tuesday through
Thursday afternoons.
- Drier conditions with temperatures nearer normal this weekend.
&&
.MESOSCALE UPDATE...
Issued at 941 PM EDT Mon Jul 29 2024
Convection is most concentrated near and ahead of a midlevel
perturbation seen in 7.4 micron water vapor satellite imagery
crossing central Indiana. Enhanced warm advection at the leading
edge of EML plume is where a supercell evolved earlier with
persistent deep rotation and deviant motion. VWP-derived hodographs
show enough low level elongation and curvature for additional
supercells, with the most likely candidates being the current
cluster in Hamilton County moving into Madison County, which has
exhibited weak rotation. There appears to be enough low level
buoyancy for an isolated tornado threat with any additional
sustained and rightward-deviant supercells that can evolve.
Otherwise sustained multi-cells will be carried eastward by the mean
cloud bearing wind at around 25-30 mph and could pose a marginal
severe threat into the first part of the night. The greatest severe
threat will be if a larger cluster can develop a stronger cold pool
and forward propagate producing a greater wind threat. Several
convective allowing models show this process but with different
spatial placement. Given latest trends, this seems most likely to
evolve from the deeper convection now over central Illinois, and
would result in the greatest potential for organized severe
thunderstorms to be across our southwest counties roughly along and
south of a Terre Haute to Seymour line. The threat further north is
still present but should be more isolated and marginal.
An equally if not greater threat will be heavy rainfall and
flooding. Deep moist warm cloud layer will enhance precipitation
efficiency, and any location that experiences multiple rounds of
convection and/or training convection may experience flooding. There
may be an enhanced corridor of training at the western flank of any
cold pool system that can form, and this may be most likely just
southwest of our area. Will monitor closely for corridors of
enhanced flash flood potential overnight.
&&
.SHORT TERM (This evening through Tuesday)...
Issued at 214 PM EDT Mon Jul 29 2024
Synopsis -
Radar this afternoon shows new thunderstorm development along a
boundary in east Central IL that was laid out earlier today by prior
convection. The earlier MCS complex has continued to decay, pushing
southeast of Central Indiana. Cloud cover across Central Indiana has
limited heating through early afternoon, but satellite trends
suggest subsidence and decreasing cloudiness. The surface analysis
early this afternoon shows high pressure in place across the
Carolinas and low pressure in place over western Kansas. This was
resulting in warmer southwest flow spilling into the Ohio Valley.
Aloft, a negatively tilted upper trough was in place from MN to
eastern KY, with the trough axis mainly east of Central Indiana.
Still, water vapor shows plentiful moisture within the trough over
Central Indiana. Dew Points remain very moist in the lower to middle
70s.
This Afternoon and Tonight -
SPC mesoanalysis pages shows CIN across central Indiana has
dissipated and CAPE of 1500-2000 J/KG present. IND ACARS soundings
showing plenty of CAPE aloft also, but just a lower level inversion
in place at the moment. This is expected to change as the clouds
continue to dissipate and lead to heating into the middle 80s. This
should trigger convection by late this afternoon and evening. HRRR
and several DESI members suggest strong thunderstorm development
late this afternoon and evening. A favorable column will remain
present along with warm air advection and the cyclonic flow aloft.
Thus many elements are in place tonight for continued showers and
storm development. Tornadoes cannot be ruled out given the very high
dew points that will result in low LCL`s. Best area for development
will be along and south of I-70, particularly within a IND-HUF-BMG
triangle area. Very high pwats will result in efficient rain
production. Torrential rains will be possible resulting in Flooding
and this will remain a threat.
Overnight, models suggest that convection will continue to diminish
storms as they exit southeast. Remnant lower level moisture along
with clearing skies and light winds will allow for the development of
patchy fog overnight. No strong change in air mass is expected, and
dew point depressions are expected to fall to 1-2F or less. Thus a
least patchy fog will be expected. Look for overnight lows in the
upper 60s in rural locations and lower 70s.
Tuesday -
The very warm and humid air mass is expected to remain in place on
Tuesday. Models suggest ridging building aloft as warm air advection
continues. 850MB temps are suggested to reach near 24C through the
afternoon as a thermal ridge is expected to build across Indiana
from the plains. Little in the way of forcing aloft will be present.
Forecast soundings suggest a capped column with a mid level
inversion in place due to the warm air advection aloft. An isolated
afternoon storm cannot be rules out across southwest central Indiana
where the cap may be a bit weaker. Small pops might be used here.
Thus after morning fog burns off, look for a partly to mostly sunny
day along with hot weather. Look for highs in the lower to middle
90s.
&&
.LONG TERM (Tuesday night through Monday)...
Issued at 214 PM EDT Mon Jul 29 2024
Much of the long term will remain rather unsettled as
central Indiana is positioned down stream on an amplified ridge, with
a succession of upper level waves moving over northern portions of
the CONUS. Also of not will be the presence of a quasi-stationary
boundary that will be the focal point for continued convective
initiation each day through Friday. As we enter the weekend, the
troughing to our NW looks to become more prominent, pushing central
Indiana into a potentially cooler and drier northwest flow for the
coming weekend.
The mesoscale environment will largely be synonymous with a typical
high CAPE/Low Shear pattern, outside of increases to shear in the
evening and overnight associated with nocturnal LLJs. Those type of
patterns typically lead to robust convection on the periphery of the
moisture tongue and along any instability gradient. This general
area should be broadly over the Ohio Valley each of Wednesday
through Friday, but there is still some uncertainty on the specific
locations. Given the high probability of steep low level lapse
rates, and high low level moisture, linear complexes are the most
likely mode, with high winds and isolated tornadoes possible within
any organized structure. Also of concern will be trailing boundaries
along the moisture axis leading to training thunderstorms and
flooding. This will become an even greater concern late week if
these MCCs develop over similar areas.
The amplifying pattern late week into the weekend, with central
Indiana between the ridge axis well to the west and trough axis to
the east, along with southward push of a cooler and drier Canadian
high pressure center, will bring temperatures and humidity back down
nearer seasonal normals, with highs in the mid to upper 80s and
dewpoints back into the 60s.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 649 PM EDT Mon Jul 29 2024
Impacts:
- Thunderstorms increasing this evening
- Some fog with IFR or worse possible late tonight
Discussion:
Some MVFR stratus is possible in the near term, but is not expected
to be consistent. Thunderstorm coverage may be somewhat limited, but
probability is high enough for a window of TEMPO thunder this
evening. Afterwards, cloud cover is the caveat to fog formation but
moist ground and light winds and perhaps some cloud breaks could
allow for some fog. Potentially locally dense. Amendments for storm
timing and fog magnitude will be needed through the evening and
tonight.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
MESOSCALE...BRB
SHORT TERM...Puma
LONG TERM...Updike
AVIATION...BRB
Area Forecast Discussion
National Weather Service Northern Indiana
217 PM EDT Mon Jul 29 2024
.KEY MESSAGES...
- Scattered clusters of showers and storms should develop this
afternoon and are expected to persist through the evening (40-60%
chances). Widespread severe weather is not expected, but some storms
may produce gusty winds and locally heavy rain.
- Several rounds of showers and storms are possible this upcoming
week, with low confidence in timing, intensity, and potential
impacts. Each day`s rain and storm chances will be contingent on the
previous day and where in the Midwest any lingering boundaries set
up.
- There are Marginal Risks for severe weather Tuesday night into
Wednesday midday, and again Wednesday evening into Thursday morning.
Confidence is low in timing, coverage, and intensity of storms.
- Very hot and humid this week with highs in the upper 80s to low
90s and dewpoints in the mid to upper 70s. Peak afternoon heat
indices may be as high as the mid 90s to near 100 Wednesday and
Thursday, but this is highly dependent on coverage of showers and
storms.
&&
.DISCUSSION...
Issued at 216 PM EDT Mon Jul 29 2024
With the new 12Z suite of model guidance, there is now better
certainty and a general consensus in the setup over the next 48-72
hours. A NW flow pattern has emerged this week, with potential for
one or more MCSs to ride the periphery of the growing Central CONUS
ridge and potentially impact our area through at least Thursday. We
already had one MCS develop across IA/MO/IL and decay as it moved
eastward this morning. With clearing evident in northern Illinois
and northwest Indiana on the latest GOES satellite imagery this
afternoon, there are chances for redevelopment. Clusters of
scattered showers and storms will be possible this afternoon and
evening (especially in northern Indiana). A few storms could be
strong this evening, with the main threats being gusty winds and
heavy rain. Storms gradually move eastward and taper off after 06-
09Z as diurnal heating and better instability is lost. Better
chances for storms will likely be in central/southern Indiana
tonight as the remnant outflow boundary from this morning`s MCS will
spark new storm development south of our CWA overnight.
The daytime hours on Tuesday will likely end up being dry due to the
aforementioned boundary being south of the CWA. The lull in
convection won`t be for long though as the newest 12Z CAMs,
alongside the RAP and NAM, depict another MCS to grow upscale across
IA/IL/IN in the late Tuesday night/Wednesday midday timeframe.
Depending on where the instability gradient is, any remaining
outflow boundaries, and the orientation of the MCS, this MCS could
clip or fully move through our CWA. SPC has maintained a Marginal
Risk for both the Day 2 and Day 3 outlooks, which is warranted given
the potential threat but also the considerable uncertainty.
Soundings for around 12Z Wednesday from the RAP and NAM depict a
favorable environment for severe weather with 2000 to 3000 J/kg
MLCAPE, 25 to 30 kts of 0-6km shear, low and mid level lapse rates
around 7.5 C/km, and ~1100 to 1400 J/kg of DCAPE. Primary threats
would be locally heavy rainfall and damaging wind gusts if upscale
growth occurs overnight Tuesday into Wednesday morning.
Another MCS is possible Wednesday night into Thursday morning, and
this would be when the best chances for severe weather would be.
With favorable shear (30-40 kts of 0-6km) and ample instability (up
to 3000 to 4000 J/kg MLCAPE), severe weather is possible but
conditional. There is lack of a forcing mechanism which could
inhibit storm development. The main cold front and associated upper
level support lag until Thursday, meaning, without a source of lift,
storms would likely fail to grow upscale and/or maintain intensity.
Alongside rain/storm chances this week, increasing WAA will allow
for the heat and humidity to increase substantially early to
mid week. Southerly/southwesterly flow is already advecting a
plume of Gulf moisture into the Midwest, raising dewpoints to
the low to mid 70s. There is high confidence in hot, humid
weather midweek with highs in the upper 80s to low 90s each day.
With hot, humid weather returning, heat indices climb into the
mid to upper 90s, especially Wednesday and Thursday. Depending
on storm coverage, Heat Advisory headlines could be needed.
Long range models show no signs of the heat and humidity
fading...maybe a few degrees `cooler` next weekend as an upper level
low pivots through the Great Lakes, but trends for the first week of
August are already showing a continuation of highs in the upper 80s
to low 90s.
&&
.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 134 PM EDT Mon Jul 29 2024
South winds 10-12kt with higher gusts will continue this
afternoon before gradually veering more southwesterly as the day
progresses. Have added a tempo group for thunderstorms at SBN
during 22z-02z time frame given latest guidance; MVFR/IFR
conditions possible in heavier storms. Confidence remains lower
further east so have left VCTS at FWA for now. Overnight,
MVFR/IFR ceilings are likely to roll back into the area but a
weak westerly flow around 5-7kts should keep stuff just off the
surface, thus precluding the addition of lower visibilities into
the forecast.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Johnson
AVIATION...Norman
Area Forecast Discussion
National Weather Service North Platte NE
631 PM CDT Mon Jul 29 2024
.KEY MESSAGES...
- Isolated thunderstorm chances both this afternoon and evening
and tomorrow afternoon and evening.
- Hot and humid conditions will combine to create potentially
dangerous heat index readings Tuesday.
- A mainly dry and warm pattern develops late in the week and
continues into the upcoming weekend.
&&
.SYNOPSIS...
Issued at 333 PM CDT Mon Jul 29 2024
H5 analysis from this morning had a fairly low amplitude pattern
across most of the CONUS. Closed low pressure was located over
Cape Cod. Further west, a strong shortwave trough extended from
northern Wisconsin into northern Illinois. Across the central
and southern plains, low amplitude ridging extended from north
central Texas into western Nebraska. Further north, a shortwave
was noted over northern North Dakota. One last feature of note
was a shortwave trough which extended from southwestern British
Columbia south into northern California. At the surface, a weak
surface trough of low pressure extended across the western
Sandhills into western Kansas. Weak low pressure was noted over
far northeastern South Dakota, as well as far southwestern
Kansas. Abundant low level moisture was present across the
eastern half of the forecast area this afternoon as 70+ dew
points were noted at Broken bow and extended east into the
eastern Sandhills and east ern Nebraska. Elsewhere, with the
exception of the eastern panhandle, dew points were in the 60s.
As of 2 PM CDT, under mostly clear skies, temperatures ranged
from 88 degrees at O`Neill, to 94 degrees at Gordon.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 333 PM CDT Mon Jul 29 2024
The threat for thunderstorms and dangerous heat over the next
12 to 36 hours will be the main forecasting concerns in the
short term. For tonight we have a conditional threat for severe
storms across northern portions of the forecast area. Forecast
soundings indicate a heavily capped environment over the eastern
2/3rds of the forecast area. This is in an area with plenty of
available CAPE and shear for severe storms. If, and only if, we
can get some initiation over the northwestern Sandhills in the
next 2 to 4 hours, we shouldn`t see much in the way of
convection tonight. However, if we do get initiation, the mid
and upper level dynamics indicate strong potential for severe
storms. Large hail and damaging winds are the main modes late
this afternoon and evening. Linear hodographs, favor very large
hail and 40 to 50kt and 60-70 KT winds at H5 and H25
respectively, will provide plenty of wind shear aloft to
facilitate severe storms. Heading forward into the evening
hours, a damaging wind threat will accompany the large hail
threat as activity moves into northeastern portions of the
forecast area. The threat for thunderstorms will shift east of
the area overnight. The HRRR at 12z this morning indicated a
secondary area of precipitation toward daybreak Tuesday morning
in the east. This was not supported by the other CAMS, and will
leave this out of the forecast with this afternoon`s package. On
Tuesday, a dryline will be forced east approaching the highway
83 corridor Tuesday afternoon. West of this feature, H85 temps
will reach 31-33C with drier BL air noted over the western third
of the forecast area. Further east, moisture pools just to the
east of the dryline with dew points in the upper 60s to lower
70s Tuesday afternoon. The combination of these dew points along
with expected highs in the upper 90s east of highway 83 Tuesday
afternoon, will lead to an extended period of heat indices of
100 to 105. That being said, will hoist a heat advisory from
noon to 8 PM CT Tuesday, east of highway 83. Late Tuesday
afternoon into Tuesday evening, another round of isolated
thunderstorms appears to be possible over northeastern portions
of the forecast area. This threat will be conditional once again
as we remain capped for a large portion of the day. If storms
can initiate, they will have a good potential to become severe
given 40 to 50 KTS of bulk layer shear and SB CAPES of 4000 to
5500 J/KG.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 333 PM CDT Mon Jul 29 2024
On Wednesday, a northern stream trough will approach the
western Dakotas and western Nebraska. The latest deterministic
NAM12 and GFS solns have the bulk of thunderstorms over eastern
South Dakota and eastern Nebraska Wednesday afternoon/evening.
The latest NBM soln does have some low pops in the eastern third
of the forecast area and this seems plausible given the model
solns this morning. After Wednesday night, we will see a re-
establishment of ridging and high pressure over the western
CONUS. This will place the FA in weak northerly flow aloft into
the first half of the weekend leading to very limited chances
for precipitation and very warm temperatures.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 627 PM CDT Mon Jul 29 2024
Isolated thunderstorms will be possible across the northern
Sandhills this evening. This could impact KVTN, KANW, KONL and
KTIF terminals, with gusty erratic winds and large hail the
main concern. Storms are expected to be out of the area by
midnight and VFR conditions will prevail the rest of the period.
Winds will remain light overnight, generally less than 10 kts.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon to 8 PM CDT Tuesday for NEZ006>010-
026>029-038-059-071.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...Gomez
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
931 PM EDT Mon Jul 29 2024
.SYNOPSIS...
Humidity returns today as high pressure pushes offshore. This will
bring the chance for thunderstorms along and west of the Blue
Ridge today. More widespread shower and thunderstorm activity is
expected Tuesday as a piece of shortwave energy traverses the
region. The heat builds Wednesday through Friday with additional
shower and thunderstorm chances as a front washes out nearby.
Another cold front should push across the area late in the
weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
Storms have finally cleared the area this evening. A few
sprinkles or light showers remain to the west of the Blue Ridge,
but these remaining showers should dissipate over the next
couple hours. Mainly dry conditions are expected overnight,
with mostly cloudy skies and lows in the low-mid 70s to the east
of the Blue Ridge, and mid 60s to near 70 to the west of the
Blue Ridge.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A shortwave trough currently pushing through northern portions
of Illinois and Indiana will be a weather maker to watch for
Tuesday. A number of high-resolution models depict a remnant
mesoscale convective vortex (MCV) through the general Mid-
Atlantic region. While the associated convective line likely
dives southward into the Tennessee Valley in the morning, that
residual spin of the parent vortex bears watching. Solutions
remain quite variable but MCV circulations are notorious for
augmenting convective development, particularly during the core
heating hours. The latest 12Z HRRR favors the most robust
scenario with widespread thunderstorm activity on Tuesday
afternoon/evening. However, at this juncture, there are too many
unknowns which includes today`s development over the Midwest
which sparks off this series of possible convective events.
On the temperature side of things, Tuesday likely yields
slightly cooler temperatures owing to the increased cloud cover.
Forecast highs top out in the upper 80s to near 90 degrees, with
mountain locations in the 70s to low 80s. A steady period of
southerly winds does raise humidity levels as dew points rise
into the low 70s again. Some of the daytime convection likely
persists after dark. However, there is a signal of a drying
trend into the overnight hours. This comes with a mild night as
low temperatures hold steady in the low/mid 70s, with mainly
mid/upper 60s from the Blue Ridge westward.
A series of low amplitude shortwaves lurk farther upstream.
However, these appear to be more diffuse looking and are even
accompanied by subtle height rises. Consequently, convective
chances do not look as impressive on Wednesday. However, one
thing that does look fairly certain is the heat will be back as
highs soar back into the mid 90s. With the trough/weak frontal
passage, winds shift from southerly to mainly west-
southwesterly. The added downslope component should lead to
enough mixing to scour out some of the highest dew points. As
such, heat index values are likely to top out in the 98 to 103
degree range. Expect any remaining shower/thunderstorm chances
to wane by nightfall given the loss of heating. Overnight lows
remain seasonably mild, generally around 5 to 10 degrees above
climatology.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Daily shower and thunderstorm chances through the long term...
Broad NW flow at the mid-levels will start the period on Thursday.
There could be a remnant MCV in the vicinity of the Mid-Atlantic
depending on how a potential upstream MCS evolves in the Ohio
Valley. The MCV would aid in convective development making it more
widespread. If this does not occur, convection appears to be more
isolated in nature and focused along terrain circulation (maybe the
bay breeze).
Come Friday, a cutoff low will move over the Great Lakes/Ohio
Valley. This will yield height falls over the local area which
persist through much of the weekend. A cold front associated with
the ULL will move through sometime Saturday or Sunday depending on
your model guidance of choice, but recent guidance has trended
slower with more of a Sunday passage. Overall severe threat looks
low until the better forcing arrives on Saturday/Sunday. However,
Thursday and Friday do have the potential for higher DCAPE which
would result in the potential for localized downbursts. Locally
heavy rainfall appears possible, but severe to extreme drought
conditions do not support a flooding threat.
In terms of temperatures, a warming trend is likely through the long
term until FROPA. This will result in heat indices near 100-110
across the lower elevations Thursday and especially Friday.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Earlier thunderstorms have cleared the area, leading to VFR
conditions across the area this evening. Low clouds may start to
form just prior to daybreak, with MVFR, and eventually IFR
conditions possible for a time early tomorrow morning.
Improvement back to VFR conditions is expected by around mid-
morning tomorrow.
Convective chances are likely to increase on Tuesday in response
to an approaching mesoscale convective vortex. However, its
existence is dependent on a lot of factors which are very
uncertain at this time. Restrictions are certainly possible at
times, particularly on Tuesday afternoon and evening. Outside of
these thunderstorms, expect VFR conditions for much of the day
underneath mostly cloudy skies. Thunderstorm chances decrease
into Wednesday with VFR conditions likely at the terminals. For
the winds, southerlies up to 15 knots are expected on Tuesday
with a shift to west-southwesterlies by Wednesday.
Daily potential for diurnal showers and thunderstorms...
coverage looks greatest with FROPA Saturday or Sunday.
&&
.MARINE...
Earlier thunderstorms have cleared the waters. SCAs remain in
effect within southerly flow through tonight and into the day
tomorrow.
With the threat of thunderstorms in the forecast on Tuesday,
there may be need for some Special Marine Warnings late in the
afternoon through the evening hours. Otherwise, the background
southerly winds will likely yield some channeling effects up and
down the Chesapeake Bay. Thus, Small Craft Advisories were
extended through a good chunk of Tuesday. These elevated winds
could persist into early Wednesday over the more southern
waters. Winds shift to southwest to westerly on Wednesday with
maximum gusts up to around 10 to 15 knots.
Thunderstorm chances increase Thursday into the weekend which
may require SMWs.
SCA conditions are possible beginning late Saturday and Saturday
night and perhaps into Sunday depending on when FROPA occurs.
&&
.TIDES/COASTAL FLOODING...
Water levels will rise tonight as southerly winds strengthen.
Minor coastal flooding is possible this this week, particularly
at Annapolis.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 6 PM EDT Tuesday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT Tuesday for ANZ530>534-537-
539>541-543.
&&
$$
SYNOPSIS...BRO
NEAR TERM...KJP
SHORT TERM...BRO
LONG TERM...CPB
AVIATION...BRO/KJP/CPB
MARINE...BRO/KJP/CPB
TIDES/COASTAL FLOODING...LWX
Area Forecast Discussion
National Weather Service Pocatello ID
147 PM MDT Mon Jul 29 2024
.SHORT TERM...Tonight through Tuesday Night.
Early afternoon satellite imagery shows a H5 Pacific trough
moving onshore to the PacNW and WRN Canada as skies remain mostly
to partly clear with areas of wildfire smoke overhead. Conditions
will remain dry today outside of isolated showers and storms along
the Montana border region but that will quickly change for
Tuesday as this H5 trough passes overhead. Look for increasing
clouds building in NW to SE overnight tonight with precipitation
following suit, primarily in the CNTRL Mountains and along the
Montana border. This is where the NBM and HREF models keep the
bulk of precipitation with the mean values around 0.01-0.10" in
Custer County and along the Montana border and 0.10-0.25" in Lemhi
County, elevation dependent. Given a 20-60% chance of
thunderstorms across the Upper Snake Plain and CNTRL Mountains
into Montana, we will see locally higher totals in that 0.25-0.50"
range with the ensemble HREF maximum totals up around 0.50-0.75"
in portions of the CNTRL Mountains. That remains a very high-end
solution. Given PWATs in that 0.50-0.80" range, we will see a mix
of wet and dry storms with stronger storms capable of producing
wind gusts to 40 mph, moderate to heavy rain, and frequent
lightning with a RED FLAG WARNING in effect for FWZ 411, 475, and
476 due to scattered coverage of thunderstorms.
As this Pacific trough departs NE Tuesday night, progressively
drier conditions will build in from the west with dry conditions
returning regionwide by early Wednesday morning. Highs today will
be in the 80s to low 90s which is near seasonable levels but they
will cool for Tuesday associated with that trough passage putting
highs back to the 70s and 80s. Given this exchange of different
airmasses, winds will remain breezy peaking each afternoon with
gusts to around 20-40 mph. MacKay
.LONG TERM...Wednesday through next Monday.
Confidence continues to increase in a large, stagnant dome of
high pressure re-establishing over the Four Corners region and
dominating our wx from the rest of the the week right through this
weekend and into early next week, with universal support across
long-range deterministic models and ensemble clusters. This spells
another HEAT WAVE. ECMWF EFI continues to run 0.8 to 0.9 for high
temps by Fri/Sat/Sun suggesting that even compared to this
normally hot time of year, the overwhelming majority of EC
ensemble members are coming in warmer than the model climatology,
and HeatRisk values rise to moderate to major during this same
period. Thus, expect highs in the 80s Wed to warm to the 90s and
low 100s by Fri and hold there through the rest of the forecast
period. Raw GFS/EC MaxT values are unsurprisingly coming in
several degrees warmer than the NBM with some spots reaching
100-110, but the bias- corrected versions of these models are
within a couple degrees of NBM guidance as is WPC guidance, and
feel comfortable running with the NBM highs at this time. A HEAT
ADVISORY may eventually be needed with modest overnight temp
recovery in some areas. The only fly in this hot, sweaty ointment
will be the potential for some monsoon moisture to start advecting
northward on the back/west side of the high. The earliest hints
of this appear in deterministic guidance (especially the Canadian)
on Fri, but chances increase with more universal model support
Sat and Sun...suspect we will remain hot and dry until the
weekend. NBM currently carries limited areas of very light PoPs
both days Sat/Sun, and would expect PoPs to increase/broad-brush a
bit more if models remain consistent and confidence increases in
the days ahead. These storms and associated cloud cover may
briefly/intermittently take the edge off high temps in some spots,
but overall coverage may remain isolated and of course pose the
risk of lightning. 01
&&
.AVIATION...For the 18Z TAFS through 18Z Tuesday.
Predominant VFR and smoky conditions will continue for Monday
under mostly clear skies ahead of increasing clouds for Tuesday as
our next Pacific trough moves in. Given increased wildfire smoke
from regional wildfires to our west, have gone ahead with 6 SM FU
for all TAF sites but keep in mind we may see occasional lower
visibility at times dependent on where higher concentrations of
smoke end up. Associated with the trough passage on Tuesday, we
may see some improvement to the smoke. Winds will be slightly
breezy both this afternoon and Tuesday afternoon with gusts to
around 15-30 kts at all terminals. Isolated rain showers/virga
will pass overhead for throughout the day on Tuesday with a 10-30%
chance of thunderstorms at KIDA and KDIJ during the afternoon and
early evening hours. MacKay
&&
.FIRE WEATHER...
As a Pacific trough moves onshore today to the PacNW and WRN
Canada, winds will be elevated this afternoon and evening with
gusts to around 20-40 mph. With RHs in the teens primarily in FWZ
410, 475, and 476, a RED FLAG WARNING remains in effect until 2100
MDT tonight with near critical fire weather conditions possible
elsewhere where this combination of wind/low RH exists. For
tomorrow, that trough will move overhead supporting isolated to
scattered showers and thunderstorms. The bulk of precipitation
accumulation will remain light and confined to the CNTRL
Mountains, Upper Snake Plain, and ERN Highlands. This is where the
NBM and HREF models keep the bulk of precipitation with the mean
values around 0.01-0.10" in Custer County and along the Montana
border and 0.10-0.25" in Lemhi County, elevation dependent. Given
a 20-60% chance of thunderstorms across the Upper Snake Plain and
CNTRL Mountains into Montana, we will see locally higher totals in
that 0.25-0.50" range with the ensemble HREF maximum totals up
around 0.50-0.75" in portions of the CNTRL Mountains. That remains
a very high-end solution. Given PWATs in that 0.50-0.80" range,
we will see a mix of wet and dry storms with stronger storms
capable of producing wind gusts to 40 mph, moderate to heavy rain,
and frequent lightning with a RED FLAG WARNING in effect for FWZ
411, 475, and 476 from 1200 to 2100 MDT Tuesday for scattered
thunderstorms.
As this Pacific trough departs NE Tuesday night, progressively
drier conditions will build in from the west with dry conditions
returning regionwide by early Wednesday morning. Highs today will
be in the 80s to low 90s which is near seasonable levels but they
will cool for Tuesday associated with that trough passage putting
highs back to the 70s and 80s. Given this exchange of airmasses,
winds will remain breezy again for Tuesday with gusts to around
20-40 mph but with much higher humidities, have held off on any
RFW issuance.
Following this trough early in the week, high confidence
continues to support a H5 ridge of high pressure building in
starting midweek through late this week. This will bring a return
to above normal temperatures and very dry conditions with light
winds each day. Moisture moisture working clockwise around this
region of high pressure over the West may lead to some isolated
showers and storm working back into Idaho by the weekend into
early next week but confidence remains low as conditions remain
predominantly dry. MacKay
&&
.AIR QUALITY...
Air quality and visibility continue to be impacted from wildfire
smoke associated with several large wildfires currently burning in
California, Oregon, and Nevada. The latest HRRR smoke model shows
increasing smoke building into SE Idaho today with increased
uncertainty on exactly how much of that smoke will remain in place
on Tuesday as an Pacific trough passes overhead. Have maintained
areas of smoke in the forecast through 6 AM MDT Tuesday before
transitioning to patchy smoke from 6 AM MDT Tuesday to 6 AM MDT
Wednesday.
Expect continued degraded air quality today into tonight with
less confidence into Tuesday. Air Quality Alerts remain in effect
for much of eastern Idaho, relayed from our partners at the Idaho
Department of Environmental Quality (Idaho DEQ). The current AQI
as of 12 PM MDT Monday ranges from moderate to unhealthy across
across all of SRN Idaho with satellite imagery showing widespread
smoke situated overhead. MacKay
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT this evening for IDZ410-475-476.
Red Flag Warning from noon to 9 PM MDT Tuesday for IDZ411-475-
476.
&&
$$
Area Forecast Discussion
National Weather Service Raleigh NC
808 PM EDT Mon Jul 29 2024
.SYNOPSIS...
A mid and upper-level trough and accompanying very moist air mass
will move into the region this afternoon and remain through at least
mid-week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 800 PM Monday...
...Trending mostly dry overnight...
Convection over the past several hours has largely remained south
and west of the area, generally tracking along the stronger
instability gradient over the western portions of the Carolinas and
upstate Georgia, and occasionally clipping the far western Piedmont
counties before dissipating.
Both the severe and flooding threats have passed. For the
remainder of the night, isolated to widely weak convection will be
possible as weak disturbances move through the area.
Otherwise, it will remain mostly cloudy with overnight temperatures
cooling another few degrees down into the mid/upper 60s north
to lower 70s elsewhere.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 328 PM Monday...
A short-wave trough will pivot over the Coastal Plain early Tuesday
morning. Associated nocturnal convection may be ongoing across our
east, which should dissipate with time early Tuesday morning.
Further west, a strong MCS will migrate over the mountains and
foothills through sunrise Tuesday. Most of the deeper convection
associated with this feature will follow the stronger theta-e
gradient and dive to our southwest. However, can`t rule out a
stronger isolated storm along the outflow making it over the
mountains and trickling into our far southwest Piedmont through noon.
As we pivot to later in the day, a brief lull in precipitation
appears likely via subsidence behind the departing short-wave.
However, convection associated with a passing MCV will likely
develop mid to late afternoon primarily across the northern
Piedmont. This activity will spread eastward through the evening,
but coverage may be pretty limited to the Piedmont/Coastal Plain.
Bulk layer shear won`t be overly impressive (~10 to 20 kts) at any
point tomorrow, and thus severe weather potential appears minimal.
This is reflected in the last few runs of the HRRR Neural Network
Convective Hazard machine learning model which paints only 5 to 8 %
severe weather probabilities with convection along the NC/VA border.
Elsewhere, the probability for severe weather from this guidance is
near-zero.
CAMs indicate an additional wave of nocturnal convection may be
possible overnight Tuesday. Will maintain chance POPs into the
overnight period, with a west - east clearing trend through daybreak
Wednesday morning to account for this possibility.
Max temperatures will bump up into the mid 80s (N) to around 90 (S).
Overnight lows will dip into the lower 70s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 400 PM Monday...
Broad mid/upper troughing will be centered over the US East Coast on
Wednesday and Wednesday night, as ridging builds into the lower MS
Valley and Deep South. Forcing across central NC looks to be fairly
limited with weak height rises overspreading the area, and PW values
should be around average with NW flow aloft. So POPs are only in the
low chance range, and not too concerned about a heavy rain threat.
Isolated showers and storms will still be possible near the Piedmont
trough and sea breeze. The best chance may come with an MCS that
tracks from the OH Valley into the Southern Appalachians on
Wednesday afternoon and evening, but models differ on whether
precipitation from the system will make it this far. Thursday then
looks to have a relative minimum in precipitation chances as ridging
builds in further from the west and we get continued weak height
rises. Isolated convection will still be possible, with the best
chances again near where the Piedmont trough sets up as well as with
the sea breeze.
By Friday we start to experience some weak mid-level height falls as
the next shortwave trough and associated surface low pressure dive
into the Upper Great Lakes and OH Valley. PW values increase back to
above normal. So POPs are back to the low chance range areawide. A
better chance of showers and storms comes this weekend as the
shortwave trough moves across the Northeast US and drags a cold
front to its south that approaches our region. At this time,
forecast amounts from WPC and the latest ensemble guidance don`t
appear too impressive, but localized flooding still can`t be ruled
out in urban areas and where storms train. Shower and storm chances
may stay elevated into early next week, especially if a tropical
system develops to the east of FL (as NHC indicates is very
possible) and moisture from it gets drawn northward. At this time,
most ensemble guidance keeps the system out to sea, but plenty of
time to monitor this potential.
The main story in the first part of the extended period will be the
heat potential. Highs on Wednesday will be in the lower-to-mid-90s
with heat indices of 100-105 possible in the south and east. This
ramps up even a bit further on Thursday and Friday with maximum heat
indices from 105-110 possible from around the Triangle to the south
and east. Lows will not provide a lot of relief, especially Thursday
night when they will only drop into the mid-to-upper-70s. The
troughing and increased clouds/precipitation chances will then
provide some relief from the heat this weekend as highs drop back
into the upper-80s to lower-90s by Sunday and maybe even a bit lower
by Monday.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 735 PM Monday...
24 hour TAF period: Aside from some very brief periods of VFR
conditions, MVFR/IFR cigs will prevail at KINT, KGSO, and KRDU
through midnight. KFAY should be VFR through about midnight, but
could briefly dip to MVFR, while KRWI could bounce between VFR and
MVFR through midnight. While a shower or two is possible near KINT,
largely expect them to dissipate before reaching the terminal. KFAY
and KRWI should drop to MVFR after midnight, while at KINT and KGSO
cigs should drop from IFR to LIFR early Tue morn. Cigs should
gradually lift back to VFR through early/mid aft. There still may be
some storms moving into central NC from the west Tue aft/eve, but
coverage has decreased and is too low to include at a specific
terminal at this time. Light winds tonight will increase into the 5-
10 kt range again on Tue, with brief gusts of 15-20 kts possible.
Outlook: Mainly diurnally driven showers/storms and early morning
fog/low stratus are expected through Sat.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...CBL
SHORT TERM...Luchetti
LONG TERM...Danco
AVIATION...KC
Area Forecast Discussion
National Weather Service Tucson AZ
148 PM MST Mon Jul 29 2024
.SYNOPSIS...
Daily chances for thunderstorms continue this week. Heavy rainfall
may cause localized flash flooding. Isolated strong wind gusts
will also be possible. High temperatures should rise a few degrees
by late this week.
&&
.DISCUSSION...
Isolated to scattered convection is expected to develop this
afternoon, with greater coverage likelier further south. RAP
guidance indicates richer low level moisture remains in areas
closer to the International Border with higher mixing ratio values
boosting instability across these areas. This is where coverage of
convection today will also be greatest, with the potential for
very heavy rainfall rates. Convective layer wind under 10 knots
will lead to very slow moving thunderstorms again, while the
seasonably moist atmosphere should lead to the very heavy
rainfall rates. While coverage will decrease this evening with
sunset, convective chances may linger through the night as a mid
level low approaches from the Gulf of California. Guidance
indicates an additional draw of mid-level moisture from this low
into southeastern Arizona, which along with the added ascent may
produce additional showers and thunderstorms even through Tuesday
morning.
By Tuesday afternoon, southeastern Arizona is forecast to be on
the wrong side of an impulse ejected through this closed low,
which should create a "lower" grade monsoon day. Continued active
flow from the lingering low however may produce additional
convection overnight into early Wednesday. At this point forecast
slight chances past midnight Tuesday night were kept to Santa Cruz
and Cochise counties, but these may need to be expanded.
Daily chances for thunderstorms continue through the forecast
period this week. The other part of the story will be the building
of a western CONUS ridge, which will warm up high temperatures
across the region. This should bring high temperatures 5 to 7
degrees above normal with moderate Heat Risk levels.
&&
.AVIATION...Valid through 31/00Z.
Isolated to scattered TSRA through 30/02Z. Very heavy rainfall
with isolated strong wind gusts to near 45 kts expected with any
thunderstorm today. An isolated shower can`t be ruled out tonight
or early Tuesday morning as well. Otherwise winds generally light
this morning and under 12kts this afternoon. Aviation discussion
not updated for TAF amendments.
&&
.FIRE WEATHER...
Elevated moisture will continue with scattered afternoon and
evening showers and thunderstorms. Each day has the threat of
heavy rain, localized flash flooding and strong gusty outflow
winds. Away from thunderstorms, 20-foot winds will generally be 15
mph or less, with afternoon/early evening gusts to 20-25 mph and
light winds overnight. As high pressure builds late this week,
high temperatures should rise a bit and minimum relative
humidities should fall by a few percentage points.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
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Aviation...Edwards
Fire Weather....Edwards
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