Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/29/24
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
525 PM MDT Sun Jul 28 2024
...New AVIATION...
.SYNOPSIS...
Issued at 205 PM MDT Sun Jul 28 2024
Showers and thunderstorms will be mostly confined to mountain
locations south of Interstate 40 Monday afternoon. The exceptions
will be over the Sangre de Cristo and Jemez mountains where
isolated showers and storms remain possible. For Tuesday and
Wednesday, thunderstorm activity will trend up slightly over most
mountain ranges, attempting to spread into valley locations
during the late afternoon and evening, but struggling to survive
for very long. The monsoon high, currently over southeast NM, is
forecast to drift back toward the Four Corners on Thursday and
Friday, resulting in a surge of near surface moisture from the
east with the possibility of widespread showers and thunderstorms
returning to the area Friday and Saturday. Additionally, the
thermostat will get turned up Wednesday and Thursday afternoons as
the monsoon high strengthens over NM on its journey back to the
Four Corners region and eventually the Great Basin by next
weekend.
&&
.SHORT TERM...
(This evening through Monday night)
Issued at 205 PM MDT Sun Jul 28 2024
Drier air invading northern NM per water vapor loop has played a
significant role in the reduction of showers/storms for areas along
and north of Interstate 40. Meanwhile, slow-moving activity will be
favored over the west central, southwest and south central mts and
adjacent lower elevations. With the upper high centroid traversing
the southern zones from west-east today/tonight, expect motions to
be slow and erratic. Unfortunately, this will not bode well for the
burn scars in Lincoln County. The latest HRRR is still advertising
an organized outflow boundary originating from the upper Gila region
tracking northward into the central zones and this could make things
a tad interesting for the RGV. This may be enough to support stray
showers late this afternoon and early evening. Models indicate most
of the convection should wind down by midnight. Overall, expect low
temperatures to be a few degrees above normal.
For Monday, the aforementioned upr high will continue its eastward
migration into north central TX. This will place NM on the western
periphery of this circulation, which will slowly erode away the dry
air across the northern zones. The best convective coverage remains
in the west central and southwest mts, and isolated storms over the
northern mts can be expected. Storm motions will still remain slow,
but will have more a north-northeast trajectory given the position
of the upr high. Overall, the risk for flash flooding should remain
the same with the primary message: low probability, but high impact
scenario for our most sensitive scars in Lincoln County. Meanwhile,
heat risk impacts will increase, particularly from eastern Union to
Chaves counties, including Clayton, Tucumcari, Clovis/Portales and
Roswell. Heat Advisory criteria in these areas is 105F. The NBM has
projected a 53% chance of meeting this criteria at Roswell and 13%
at Tucumcari. Will not issue headlines at the moment, but that does
not discount the heat-related risks for these areas. DPorter
&&
.LONG TERM...
(Tuesday through Saturday)
Issued at 205 PM MDT Sun Jul 28 2024
Weather prediction models remain in good agreement with regard to
Tuesday and Wednesday, shifting the center of the monsoon high
eastward over the Red River Valley of north TX and southern OK.
South and southwest winds on the western periphery of the high
will draw up additional low and mid level monsoon moisture into
areas primarily west of the central mountain chain Tuesday and
Wednesday. Mid level (700-500 mb) lapse rates of 8.3C/km from the
NAM12 remain indicative of storms that will struggle to survive
for long without plentiful outflow boundary interactions given the
limited surface moisture progged for Tuesday afternoon. Moisture
increases Tuesday night and Wednesday for better chances of
showers and storms in valley and basin locations during the late
afternoon and early evening. Scattered thunderstorms are forecast
elsewhere along and west of the Sangre de Cristo mountains and
central highlands on Wednesday. Atmospheric moisture content
(precipitable water or PWAT) is forecast by the NAM12 to
increase to above average levels for late July on Wednesday, so
the storms that develop will be capable of producing torrential
rainfall rates upwards of 2" per hour. Thursday remains quite the
intriguing day with a backdoor front, plentiful low level
moisture, and a monsoon high center migrating to the northwest
over NM. Weak storm steering flow aloft and copious low level
moisture will likely result another day where storms over most if
not all mountain ranges become torrential rainers. Friday
continues along those same lines, but with more storm coverage
forecast and slightly stronger steering flow with a monsoon high
center directly over northern NM. The high eventually migrates
back over UT next weekend for a continued active period for
central and northern NM. Light to moderate northeasterly shower
and thunderstorm steering flow is forecast.
&&
.AVIATION...
(00Z TAFS)
Issued at 521 PM MDT Sun Jul 28 2024
Isolated storms are slowly drifting around southwestern and
south-central NM this hour. Little to no impact is expected from
these cells at any TAF terminal this evening. VFR prevails
overnight with another relative down day for afternoon showers
and storms Monday. A rogue storm developing along the Continental
Divide may have a chance to reach KGUP, but confidence is too low
this far out to include a mention of this just yet. LLWS will
again be present at KTCC, and to lesser extent below TAF criteria
at KROW at 015/18025kt.
&&
.FIRE WEATHER...
Issued at 205 PM MDT Sun Jul 28 2024
Critical fire weather conditions are not anticipated over the next
seven days. For the early portion of the work week, very hot temps
will favor central and eastern NM with readings stretching from the
upper 90s to mid-100s. Best chances for wetting pcpn will be across
the west central high terrain, and this will expand slowly east and
north through midweek. Storm motions will remain relatively slow as
they track north-northeast. All storms will be capable of gusty and
erratic outflows. The upper high will migrate back toward the Four
Corners region with a backdoor front invading the ern plains on Thu.
This will likely increase precipitation chances areawide along with
higher humidities and cooler temperatures. DPorter
&&
.PRELIMINARY POINT TEMPS/POPS...
Farmington...................... 63 92 64 93 / 0 5 10 5
Dulce........................... 48 90 50 91 / 0 5 10 20
Cuba............................ 57 89 59 89 / 5 10 20 30
Gallup.......................... 56 90 56 90 / 10 20 20 20
El Morro........................ 58 85 57 84 / 30 40 30 50
Grants.......................... 60 89 60 89 / 20 30 20 40
Quemado......................... 59 85 58 86 / 40 60 40 70
Magdalena....................... 63 88 64 88 / 30 30 20 40
Datil........................... 58 85 57 84 / 30 60 30 70
Reserve......................... 57 90 56 91 / 50 70 30 70
Glenwood........................ 66 95 67 94 / 40 60 30 60
Chama........................... 51 83 52 84 / 0 10 10 30
Los Alamos...................... 64 87 66 87 / 5 20 10 40
Pecos........................... 61 89 62 89 / 0 20 10 40
Cerro/Questa.................... 51 86 53 87 / 0 20 10 40
Red River....................... 49 77 51 78 / 0 20 10 40
Angel Fire...................... 44 81 46 81 / 0 20 10 40
Taos............................ 54 90 55 91 / 0 10 10 20
Mora............................ 55 85 56 87 / 0 20 10 40
Espanola........................ 61 95 62 95 / 0 5 10 10
Santa Fe........................ 64 90 65 90 / 5 10 10 30
Santa Fe Airport................ 61 93 63 94 / 5 5 10 20
Albuquerque Foothills........... 70 95 71 95 / 10 10 10 30
Albuquerque Heights............. 68 97 69 96 / 10 5 10 10
Albuquerque Valley.............. 67 98 69 98 / 10 5 10 10
Albuquerque West Mesa........... 68 96 69 97 / 10 5 10 10
Belen........................... 65 97 66 98 / 20 5 20 10
Bernalillo...................... 68 99 69 98 / 10 5 10 10
Bosque Farms.................... 64 97 66 98 / 20 5 10 10
Corrales........................ 68 99 69 98 / 10 5 10 10
Los Lunas....................... 66 97 67 98 / 20 5 10 10
Placitas........................ 67 95 67 94 / 10 5 10 20
Rio Rancho...................... 68 98 69 96 / 10 5 10 10
Socorro......................... 68 99 69 99 / 20 10 20 20
Sandia Park/Cedar Crest......... 63 89 64 89 / 10 10 10 30
Tijeras......................... 64 91 65 91 / 10 5 10 30
Edgewood........................ 59 92 61 91 / 10 10 10 20
Moriarty/Estancia............... 57 94 58 92 / 10 10 10 20
Clines Corners.................. 59 90 61 90 / 5 10 10 20
Mountainair..................... 60 91 61 91 / 10 10 20 20
Gran Quivira.................... 61 91 61 91 / 10 10 20 30
Carrizozo....................... 67 95 67 95 / 20 20 20 20
Ruidoso......................... 61 86 61 87 / 20 30 20 40
Capulin......................... 59 89 61 90 / 0 5 5 20
Raton........................... 56 92 59 94 / 0 5 0 10
Springer........................ 56 94 58 95 / 0 5 5 10
Las Vegas....................... 57 90 58 90 / 0 10 10 30
Clayton......................... 66 99 68 100 / 5 0 5 5
Roy............................. 61 95 63 95 / 0 5 5 10
Conchas......................... 66 102 69 103 / 5 0 5 0
Santa Rosa...................... 65 98 66 97 / 5 0 5 5
Tucumcari....................... 69 103 71 102 / 0 0 5 0
Clovis.......................... 69 101 71 102 / 0 0 5 0
Portales........................ 69 102 70 102 / 0 0 5 0
Fort Sumner..................... 69 102 70 102 / 5 0 5 0
Roswell......................... 73 104 74 105 / 5 0 5 0
Picacho......................... 66 97 66 97 / 10 5 10 5
Elk............................. 63 95 63 95 / 20 10 10 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...46
LONG TERM....33
AVIATION...24
Area Forecast Discussion
National Weather Service Aberdeen SD
622 PM CDT Sun Jul 28 2024
.KEY MESSAGES...
- There is a Slight Risk (level 2 of 5) for severe storms late
this afternoon through midnight or so. The main threat with the
strongest storms will be wind gusts in excess of 70 mph, but
large hail and a tornado or two are also possible.
- There is a Slight Risk (level 2 of 5) for severe storms late
Monday afternoon and Monday evening. The main threat with the
strongest storms will be large hail and strong wind gusts.
- Elevated smoke from Canadian and western wildfires will continue
to result in a milky sky with filtered sunshine.
&&
.UPDATE...
Issued at 618 PM CDT Sun Jul 28 2024
Thus far have a few towers go up but nothing has been well
maintained more than a few scans. CAMS still support convective
development, though the HRRR is suspiciously quiet. Will continue
to watch for convective development, however while there is a weak
wave to support convection, there isn`t a low level jet to focus
and maintain it overnight.
See below for the update to the Aviation discussion...
&&
.SHORT TERM /THIS EVENING THROUGH MONDAY NIGHT/...
Issued at 316 PM CDT Sun Jul 28 2024
An upper level shortwave and associated energy will track across the
CWA this evening. A more zonal flow will set up on Monday before
another shortwave moves through late Monday afternoon and Monday
evening.
At the surface, a frontal boundary is currently situated from
southwestern South Dakota to southeastern North Dakota. There has
been some shower and weak thunderstorm activity off an on all day,
mainly to the north of the front. The front will gradually work its
way eastward and will become almost more north/south oriented over
eastern South Dakota this evening. Will likely see some thunderstorm
development over central South Dakota by early evening, then will
see additional development as the front encounters more unstable air
over eastern South Dakota and west central Minnesota later this
evening. MUCAPE values will generally be in the 1500-3000 J/kg
range. Shear will not be real strong, generally in the 20 to 30 knot
range in association with the instability, but it will be in the 30
to 40 knot range just west of the front. Some of the CAMS are more
robust than others with the areal coverage of storms, but all agree
that chances are pretty good for storms somewhere over the CWA this
evening, before they exit the CWA to the east around or shortly
after midnight. The biggest threat with the stronger storms will be
wind gusts in excess of 70 mph, but large hail and a tornado or two
are also possible. High pressure moves in late tonight and Monday
morning, bringing a brief respite in the precipitation. Another
frontal boundary then looks to track across the area Monday
afternoon and evening, and will be the focus for additional
thunderstorm development. The instability and shear will be a bit
more in line across the east, with 2000-3000 J/kg of MUCAPE and 40
to 45 knots of shear. Steep lapse rate will aid in more of a large
hail threat, but strong winds gusts cannot be ruled out.
Low temperatures tonight will be in the 60s. High temperatures on
Monday will be in the upper 80s to lower 90s. Lows Monday night will
again be in the 60s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 316 PM CDT Sun Jul 28 2024
No major model changes to the overarching long wave pattern in the long
term period. Also no distinct clustering differences among the
ensembles 500 MB pattern. Upper level high pressure will be over the
south central CONUS with a low amplitude ridge extending across the
central and northern plains states on Tuesday. This will be short lived
as a distinct trough approaches from the west late Tuesday-Wednesday.
This will initially place us in southwest flow aloft before the trough
passes late Wednesday into Thursday. At the surface broad low pressure
will be lingering through this time frame with a persistent southeast
flow allowing dewpoints to easily range from the mid 60s to mid 70s. In
fact, the NBM probability of 70 degree dewpoint temps ranges from 60-80%
along and east of the James River. It is readily easy to infer plenty
of instability through the time frame. The big question then becomes,
when and where will thunderstorms develop. A robust CAP will likely
prevent any surface based activity on Tuesday. The only exception might
be the far northeast CWA where 700 MB temperatures only have a 30-50%
chance of exceeding 12 C. Elsewhere, however, very good chances (60-
100%) of this mid level warm air being positioned over the region. Most
models are hinting at a shortwave providing enough forcing/cooling
overnight Tuesday into Wednesday morning for thunderstorm development.
A very similar set up late Wednesday into Thursday morning with the
main trough passage. The northern plains will return to more of a
northwest flow pattern Friday and through the weekend due to building
southwest CONUS high pressure.
While it was mentioned that there are no distinct clusters in the long
wave pattern, we are still seeing the persistent GEFS bias toward
excessive mixing/warm bias. NBM temperatures seem to handle this bias
well and no changes made to the blended guidance. Temperatures will
remain above normal (upper 80s-upper 90s) through the end of the work
week, with a trend toward more seasonal temperatures by the weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 618 PM CDT Sun Jul 28 2024
Terminals KABR,KATY,KPIR,KMBG
VFR conditions for all terminals, though there is the potential
for fog formation at the KATY terminal during the early morning
hours. Otherwise best potential for storms on station will be at
KABR/KATY through the evening.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Connelly
SHORT TERM...Parkin
LONG TERM...Serr
AVIATION...Connelly
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
743 PM EDT Sun Jul 28 2024
.SYNOPSIS...
Pleasant weather continues this evening as high pressure
remains over the area. A warming trend is expected next week
along with daily chances for showers and thunderstorms.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 740 PM EDT Sunday...
Key Message:
- Dry and pleasant this evening.
- High clouds building in tonight with lows in the mid-upper
60s.
High pressure at the sfc persists over most of the East Coast.
Meanwhile, a closed UL low is located off the coast of southern
New England, placing northerly flow over the Mid-Atlantic
aloft. Temperatures have started to drop off with the loss of
heating.
Overnight, sfc high pressure will slide just offshore
and a shortwave aloft will approach the region from the W/SW.
Ahead of the disturbance, high clouds will build in from the SW
to NE late tonight into tomorrow. With increasing cloud cover
and sfc flow switching around to the S, lows will not be quite
as cool as they were last night, but still dropping into the
mid-upper 60s.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
As of 330 PM EDT Sunday...
Key messages:
-A more unsettled pattern returns Monday with daily chances for
showers/storms lasting through the week.
-Highest coverage of precip looks to be Tuesday/Tuesday night
The closed off low aloft will move back into New England Monday with
a coupled low at the sfc. Sfc high pressure will remain offshore. A
series of disturbances aloft will bring daily chances for showers
and storms. Precip on Monday looks to be largely limited to western
and northern counties. CAMs have decent agreement in isolated to
scattered storms moving in from WSW Monday afternoon as the first
shortwave moves into the area. Precip likely dies out in the evening
hours. CAMs do suggest some redevelopment of showers/storms late in
the night (04z-08z) somewhere along or E of I-95 as a second
shortwave pivots through the area with the 12z HRRR being the most
aggressive on this solution. Highs on Monday still in the 80s. Will
likely stay in the low-mid 80s in the SW where cloud cover will be
thicker and precip starts earlier. Elsewhere, mid-upper 80s
expected.
Additional showers/storms are expected Tuesday. A shortwave along
with a trough axis aloft will likely mean Tues will likely have the
highest coverage of storms for the week. Have introduced some likely
PoPs, but these are still limited to the NW counties. High temps a
degree or two cooler Tuesday as more clouds are forecast, with mid
80s for most of the CWA. Any leftover convection may slowly move E
through the evening and will keep low-end chance PoPs through the
night along the coast. Lows 70-74.
A trough axis remains over the E Coast Wed. This, combined with hot,
humid conditions will lead to additional storms Wed
afternoon/evening, though confidence in coverage is lower. Keeping 30-
45% PoPs across the area with highest PoPs in the SE. Wed starts a
period of hotter weather with highs around 90. Lows Wed night in the
low-mid 70s.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 330 PM EDT Sunday...
Key Messages:
- Chances for showers and thunderstorms are expected each
afternoon/evening.
- Heat builds to end the work week, with heat indices approaching
heat advisory criteria.
Remaining somewhat unsettled moving into the extended period with
daily chances for mainly afternoon/evening convection. The synoptic
pattern will be characterized by a broad trough over the E CONUS
Thurs before the trough weakens and shifts offshore late in the
week. This will set up westerly or NW flow aloft. Weak
disturbances in the flow aloft and daily sfc troughing will
likely act to spark showers and storms. It remains difficult to
confidently say which areas and days favor the highest coverage
of rain, though Thursday looks to be driest day with only Schc
PoPs in the forecast for most of the area. Global models
continue to show MCS activity developing upstream over the
Midwest each day and while most of this would be expected to
stay or decay W of the area, will need to keep an eye on this as
we get closer in case any of these act to spark any convective
activity nearer to our area. By Friday and into the weekend, a
more defined trough may approach from the NW and some stronger
mid- level flow overspreads the area. May therefore need to keep
an eye out for some stronger storms then (machine learning
tools beginning to show a potential uptick in the wind threat).
Still a week away so uncertainty is obviously higher. Aerial QPF
is forecast to average 0.75"-2" in the day 1-7 period, so not
as wet as the previous unsettled period.
It will be noticeably warmer Thursday and Friday, with
afternoon dew points also increasing well into the 70s. Highs in
low-mid 90s Thursday, and mid 90s Friday and Saturday. Heat
indices also creep back up to 100- 105+ F and we could be
looking at a round of heat headlines Thursday and especially
Friday. Forecast overnight lows are in the 70s.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 740 PM EDT Sunday...
VFR conditions prevail through 00z TAF period with high pressure
over the region. Winds are generally from the S around 5 kt,
becoming light and variable tonight. Mostly clear skies expected
until some mid and high clouds move into the region late
tonight toward sunrise on Monday. SW winds 5-10 kt are expected
tomorrow with some gusts to 15-20 kt possible, especially at
RIC.
Outlook: Isolated showers/storms may impact the western half of
the area Monday evening with potential for MVFR/IFR CIGs in the
Piedmont Monday night. Unsettled pattern returns with increased
chances for afternoon and evening storms through mid week.
&&
.MARINE...
As of 315 PM EDT Sunday...
Key Messages:
- Generally sub-advisory conditions continue through Tuesday
although a SSW wind will increase each night.
- SCA conditions are possible Tuesday night into Wednesday due to an
increasing SSW wind.
High pressure is located along the coast this afternoon, leading to
light and variable winds over the Chesapeake Bay/tidal rivers and
sea-breeze dominant along the Atlantic coast. High pressure nudges
offshore later this evening into tonight, with the wind becoming S
10-15kt north and 5-10kt south. The wind becomes SW 10-15kt with
gusts near 20kt and SW ~10kt south by early Monday morning. Seas
will linger ~3ft off the Currituck Outer Banks through this
afternoon, with 2-3ft seas elsewhere, and 2-3ft for the entire
coastal waters tonight. Waves in the Bay will generally be ~1ft
today, and then build to ~2ft tonight and 2-3ft in the middle Bay.
High pressure settles offshore Monday and remains off the Southeast
coast through at least later this week. The wind becomes SSW 10-15kt
with occasional gusts to ~20kt for the ocean/Bay tomorrow into
tomorrow night and will typically strongest during the late
afternoon and evening hours. The best chance for marginal SCA
conditions will be Tuesday evening into early Wednesday as weak low
pressure passes northwest of the waters, tightening the pressure
gradient. SSW winds will increase to 15 to 20 knots with gusts of 20
to 25 knots possible. Local wind probs are indicating ~50-60% chance
for 20+ knot gusts over the Chesapeake Bay Tuesday night. The
pressure gradient slackens to some extent Wednesday through later
this week with a SSW wind mainly 10-15kt for the ocean and Bay, and
5-10kt elsewhere. Seas will mainly be 2-3ft Monday through much of
next week, although seas build to 3-4ft (possibly 5ft out 20 nm)
Monday night into Tuesday night N of Parramore Is and again Tuesday
night into Wednesday with the enhancement of the SSW wind. Waves in
the Ches. Bay will mainly be 1-2ft for much of the period, and 2-3ft
in the middle Bay Monday night and Tuesday night. Chances of
primarily aftn/evening showers/tstms return Monday through most of
the week.
Rip Currents: For Monday, a moderate risk is forecast for the
northern beaches with an increasing SSW wind and nearshore waves
building to ~3ft. A moderate risk is also forecast for the Currituck
Outer Banks beaches, with a low risk in Virginia Beach. On Tuesday,
a moderate risk is again forecast for the northern beaches, with a
low risk south.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...SW
NEAR TERM...AM/RHR
SHORT TERM...AM
LONG TERM...AM/SW
AVIATION...RHR
MARINE...AJB
Area Forecast Discussion
National Weather Service La Crosse WI
1051 PM CDT Sun Jul 28 2024
.KEY MESSAGES...
- Scattered showers end by early evening then shower/storm
chances increase overnight into Monday. Off and on storm
chances persist through Thursday as the heat keeps its grip
over parts of the Rockies and the central and southern Plains.
Any convective complexes through the week could affect
temperatures depending on their timing and how long the clouds
hang on.
- Heat index values are expected to be in the 80s and 90s Monday
through next Sunday with Wednesday being warmest. Warmest wet-
bulb globe temperatures are mostly in the 70s to lower 80s. At
these levels, we remain in a risk level 1 to 2 of 4 for heat
risk; Minor to Moderate for heat sensitive individuals.
&&
.DISCUSSION...
Issued at 255 PM CDT Sun Jul 28 2024
Overview:
Morning water vapor satellite imagery, 500mb heights, and lightning
showed an open wave over parts of Iowa/Missouri with northern
embedded shortwave troughs within the southwest flow aloft from
the West Coast through the Plains into Ontario. The Gulf was
open with mid and high level moisture streaming northward
through the Mississippi Valley River states. Multiple clusters
of storms were noted from KS/NE/Dakotas into northern MN and
Ontario. This is a bit messy with so many embedded vorticity
maximums. The thunder with the clusters was noted where the low
level jet was stronger; in the 30 to 45kt range.
The 19Z Visible satellite imagery showed a cumulus field over
the forecast area with an mesoscale vorticity center over
northwest Iowa. The 19Z subjective surface analysis had the
surface boundary to the west from northern WI to the Dakota with
a surface trough through the western High Plains. Temperatures
had warmed into the upper 70s to mid 80s with sticky dewpoints
in the upper 60s to lower 70s. Showers over southern WI earlier
in the morning continue to be more prevalent across south
central and southeast WI with the moisture transport and to the
northwest and southwest over parts of MN and Iowa. The latest
WSR-88D mosaic had showers mainly over southern WI with clusters
of storms over north central MN and northeast Neb. into
northwest IA.
Showers/Storms Through Tuesday:
Multiple pieces of energy will try to converge tonight into Monday
as shortwave troughs move east across the Northern Plains and energy
from western Iowa slides east. The 25kt 900mb low level jet over
the Missouri River Valley is forecast to strengthen 30 to 50kts
overnight. The stronger axis of winds is across Kansas into
Missouri with weaker, more focused 30 to 40kts winds into Iowa and
southeast MN Monday morning. Will need to continue to monitor
the MCV to the west. The 18Z HRRR and RAP have increased the
cells develop a little farther north into northeast Iowa earlier.
Rain chances increase from the west overnight spreading
east Monday morning. The low level jet weakens 15-18Z, so
should see an overall decrease in coverage. Rain appears likely
for much of the area, but due to the focused forcing in some
areas and not so much in others, rainfall could vary from trace-
0.10" in spots to .5 to 1" in others. With heating during the
day and the upper level trough over the area, there should be an
uptick is coverage and intensity with precipitation ending from
west to east as the trough shifts east.
We remain in a severe weather risk level 1 of 5 Mon. Stronger
storms could develop with heating, but the instability and shear
appear more favorable south of the local area. Precipitable water
values of 1.5 to 2" will accompany the storms with warm cloud depths
in excess of 4km. Storm motions vary from 5 to 15 or 20kts, thus
locally heavy downpours of rain could occur Monday.
The next upstream wave over the Dakotas Monday is forecast to push
into the area Tuesday as mid-tropospheric ridging is also
trying to build east. There is sufficient mid level moisture,
but weakening forcing. The deterministic and hi-res models are
mostly dry with spotty precipitation. Our current forecast is
dry, but did add pops for spotty/storms with the elevated
instability around 3000 J/kg as it may be on the periphery of
the cap. As we refine the timing and location of potential
convection, we can further increase pops.
Above normal temperatures and uncomfortable humidity with highs in
the 80s Monday and 80s to lower 90s Monday.
The Extended:
Still unsettled Wednesday and Thursday with multiple pieces of
energy with the next trough. The warmer capping 700mb temperatures
remain to our west, thus we remain vulnerable to mesoscale
convective complexes on the periphery of the ridge. There continues
to be a signal for an MCS or two affecting parts of the local area.
There is not good model agreement in how these evolves at this time,
but at least the potential for some beneficial rain for some.
Ridging builds in for Friday through Sunday with normal to above
normal highs in the 80s. Our current forecast is dry, but will need
to monitor for shortwaves moving across Canada into the Northern
Plains which could touch off storms.
Heat this Week:
Heat index values are in the 80s and 90s Monday through next Sunday
with Wednesday being warmest. Warmest wet-bulb globe temperatures
are mostly in the 70s to lower 80s. At these levels, we remain in
the level 1 to 2 of 4 for heat risk; Minor to Moderate for heat
sensitive individuals.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1045 PM CDT Sun Jul 28 2024
It is a low confidence aviation forecast for tonight as
multiple weak shower and thunderstorm complexes shift through
the region. Did add showers early on in the TAFs where
confidence in occurrence is higher and VCSH through the mid-
morning hours before the weather system departs. Ceilings and
visibilities will hinge on how storms evolve overnight, with the
greatest potential of restrictions staying south of the TAF
sites. Did add an MVFR ceiling mention to account for the
possibility of restrictions, but there is a 20-30 percent chance
that we see IFR or LIFR conditions, mainly towards RST.
Restrictions improve quickly by mid-morning with VFR conditions
expected for the rest of the TAF period. Winds will generally be
around 5-10 kts and veering from the south to west in the
afternoon.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Zapotocny
AVIATION...Skow
Area Forecast Discussion
National Weather Service Birmingham AL
753 PM CDT Sun Jul 28 2024
...New SHORT TERM, AVIATION...
.SHORT TERM...
(Tonight through Tuesday)
Issued at 726 PM CDT SUN JUL 28 2024
Relatively slow moving thunderstorms and thunderstorms moving over
the same locations more than once produced rainfall amounts of 3-5
inches in several locations today. Due to the tropical airmass
overhead, the rainfall rates were extreme and some flash flooding
was observed. The latest radar depiction has thunderstorms from
near Birmingham to Selma and westward to near Linden. This
activity will move west to east and was associated with lift from
a passing short wave trough. The latest RAP analysis has the south
and east as the other areas no worked over by convection earlier
in the day. Therefore, expect the storms to continue moving west
to east this evening and potentially make it to the Georgia state
line. The current pops have less chances far southeast and will
monitor this closely the next hour or so before possible increase.
It appears that another short wave trough moves into the area
toward daybreak and there will be increased rain chances again
late tonight and into Monday.
The storms overnight may still produce locally heavy rain, with
some areas receiving torrential rainfall. Some locations may
receive 3-4 inches of rain. Made some adjustments to the pops and
temperature trends.
75
Previous short-term discussion:
(This evening through Monday)
Issued at 117 PM CDT SUN JUL 28 2024
Monday.
Broad mid-level ridging will continue to amplify over the
Southern Plains while a longwave trough extends from over
Wisconsin southeast to over Indiana as the offshore coastal storm
impacts from New York City to Boston. A northwesterly flow pattern
will develop aloft over the area with a few shortwaves depicted
in modeling during the day Monday moving southeast over the area.
Surface high pressure will be found off of the Carolina coastline
while low pressure will persist across the Central Plains and
Midwest.
Mostly cloudy skies with chances for showers and some
thunderstorms will be higher across the eastern half of the area
Monday while lower chances will be found to the west. Winds will
be from the west to northwest at 4-8 mph and high temperatures
will range from the mid 80s in the higher elevations northeast to
the low 90s west and southwest. The combination of temperatures
with dew point values in mid 70s will result in heat index
readings peaking from 100-102 degrees across the southwest third
of the area during the early to mid afternoon hours.
05
&&
.LONG TERM...
(Monday night through next Saturday)
Issued at 237 PM CDT SUN JUL 28 2024
Key message:
- A hotter and drier overall trend is emerging through the end of
the upcoming week. Dangerous heat indices between 105 and 109
degrees will be possible as highs top out in the mid to upper
90s starting Tuesday and potentially lasting through Saturday.
The upper level ridge will continue to build to our west over
Texas on Tuesday as the main upper trough axis ejects eastward
toward the Eastern Seaboard. A 500mb vort max will track
southeastward within the northwest flow that will trigger
scattered to perhaps numerous showers and storms primarily over
the eastern half of Central Alabama. Guidance this afternoon is
trying to keep most convective activity more toward the east, and
have adjusted PoPs accordingly to reflect those trends. The upper
level ridge will build close to 597 decameters into the lower
Mississippi Valley by Wednesday afternoon, with rain chances
decreasing as a result. Still, diurnally-driven scattered showers
and storms will be possible across the eastern and southeastern
counties. Additional upper level shortwave impulses moving
southward along the eastern periphery of the ridge will help to
synoptically support that development as well. At least scattered
convection will be possible during the afternoon hours through the
end of the forecast period.
The biggest story during the long-term forecast will be the
building heat, that will likely become a long-duration event.
Starting Tuesday, low-level moisture will remain elevated with
southerly to southwesterly flow at the surface. Dewpoints will be
hard pressed to mix down into the mid 70s during peak heating
hours Tuesday through Friday and potentially lingering into
Saturday as well. Heat indices will likely rise between 105 and
109 degrees in many locations, and Heat Advisories will be needed
if current guidance trends hold up for much of Central Alabama for
at least 4 days in a row. At the end of the period, long-range
guidance is hinting at a trough digging over the eastern CONUS
with a front headed our way as of the 12z runs.
56/GDG
&&
.AVIATION...
(00Z TAFS)
Issued at 726 PM CDT SUN JUL 28 2024
Convection was affecting several terminals this evening. Near the
northern sites, the activity was beginning to weaken and become
elevated. The lightning that was occurring was sporadic and mainly
positive. Near MGM, active thunderstorms will move into the area
from 01-03z moving west to east. Some of the rainfall may be
torrential. VFR conditions were common outside of the convection
with scattered low clouds and VFR ceilings. Another area of lift
will approach toward daybreak increasing rain chances north. The
high rain chances spread to a large part of the area on Monday.
Most terminals will experience the IFR/LIFR ceilings around 12z
lasting a few hours. Ceilings then rise through the morning but
will be impacted by the rain chances moving back in. Winds will be
light and variable overnight and most likely display a westerly
component on Monday.
75
&&
.FIRE WEATHER...
A humid airmass will remain in place through the first half of the
upcoming week as high pressure builds into the area. Winds will
become more southwesterly to westerly Monday through Tuesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 71 87 73 92 / 80 80 40 60
Anniston 72 87 73 91 / 80 90 40 60
Birmingham 74 87 75 92 / 70 80 30 50
Tuscaloosa 73 91 75 94 / 60 50 20 40
Calera 73 88 75 93 / 80 80 20 50
Auburn 73 87 74 91 / 70 90 30 70
Montgomery 74 91 75 93 / 80 70 20 60
Troy 73 89 73 93 / 70 70 20 70
&&
.BMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...75
LONG TERM....56/GDG
AVIATION...75
Area Forecast Discussion
National Weather Service State College PA
1034 PM EDT Sun Jul 28 2024
.SYNOPSIS...
Low pressure will meander south of New England before an
upstream shortwave nudges it to northern New England and Quebec
Monday night and Tuesday. Another disturbance will track just
north of Pennsylvania late Tuesday into early Wednesday,
followed by a slow-moving cold front will approach the area by
the end of this week.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Despite the seasonably unusual area of low pressure south of New
England, sfc pressures are higher to our east this evening,
resulting in easterly wind shifts at many sfc observing
stations earlier this evening before post-sunset decoupling.
Mid to high clouds continue to spill into eastern parts of our
forecast area late this evening.
Overnight forecast is fairly steady state. Mostly clear skies
will prevail across the western two thirds of the state with
those high clouds eventually covering the eastern third of
central PA. The combination of mainly clear skies, light wind,
and still relatively dry air over PA supports undercutting NBM
min temps tonight again by a couple of degrees. Although it will
not be as cool as recent nights, patchy valley fog is possible
over the valleys of Northern PA, where USGS gages indicate water
temps of 24C to 26C.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
On Monday, Central PA will be wedged between an upper low over
Southern New England and a shortwave working up the Ohio Valley
on Monday. The upstream shortwave will nudge the sfc low
northward to Northern New England and Quebec by late Monday
night and Tuesday. But in between, large scale subsidence
between these features is likely to result in a mostly rain-free
and very warm day across most of the forecast area.
However, the light southerly flow will continue to advect
increasing low level moisture into the state and the approaching
shortwave and surface warm front could support a late day
shower/tsra across the southwest part of the forecast area. GEFS
2m temp anomalies indicate highs should be 4-7 degrees above
average across the Central Mtns, while a cirrus shield
associated with the upper low may temper the heat across the
eastern counties. Max temps should range from the upper 80s to
low 90s over most of the area, with spot mid 90s possible over
parts of the South Central Mountains.
Isolated showers should linger into Monday evening over
Southern PA associated with the warm front working into the
area. However, the associated shortwave and best forcing should
pass by late Monday night, so expect rain-free conditions
heading into Tuesday morning. Surging low level moisture and a
light southerly breeze should result in much warmer conditions
Monday night than recent nights with min temps in the 65-70F
range in most spots.
The warm front is progged to lift north of the region Tuesday.
However, surging PWATs ahead of another upstream shortwave over
the Grt Lks should support plenty of cloud cover and widespread
convection by afternoon, which will hold temps down somewhat.
Highs on Tuesday will likely be 5 to 10 degrees cooler than
Monday, but will end up right around average for this time of
year. Weak mid level flow and deep layer shear indicates the
threat of severe weather is low. Latest ensemble plumes indicate
aerial average rainfall of 0.2 to 0.4 inches is most likely,
with locally higher amounts from any tsra.
Shower and thunderstorm chances will remain in the forecast
through midweek as an upper level trough is progged to pass
overhead on Wednesday. Higher PWATs will be lingering from
Tuesday`s system as we remain in the warm sector post warm
front.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Building high pressure over the western and central US will
bring an increasing threat for excessive heat and uncomfortable
humidity as the calendar flips from July to August. Current
ensemble members show us settling into a ring of fire pattern
towards the end of this week. Diurnally driven convection is
likely each afternoon through the end of the week.
The ridging out west is likely to stay firmly in place through
the course of this weekend. Long range guidance suggests the
next frontal system will slide across the Commonwealth Saturday
evening as an upper level trough dips across the great lakes and
into the northern Ohio Valley. More widespread showers and
thunderstorms are possible with this system as it will be more
than just diurnally driven.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
There is high (> 90%) confidence in VFR conditions continuing
through 18Z Monday as central Pennsylvania remains under the
influence of surface high pressure. Localized FEW/SCT clouds
along the higher elevations remain possible through 22Z Sunday
before SKC conditions prevail overnight. Fog formation remains
plausible across the northern tier and have kept with
persistence based on similar environmental set-up as the
previous two nights with RAP model soundings and HREF
probabilities of MVFR/IFR visibilities decreasing at BFD and IPT
since the previous TAF package.
Outlook...
Tue-Wed...Increasing Chcs for SHRA/TSRA. Restrictions possible.
Thu-Fri...PM SHRA/TSRA with localized restrictions possible.
&&
.CLIMATE...
A record high temperature of 87 degrees was set at Bradford
today. This ties the old record of 87 degree set in 2023.
The average temperature from January 1 to July 27, 2024 at
Harrisburg was 56.4F, which is the warmest year-to-date on
record.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...DeVoir/Fitzgerald
NEAR TERM...DeVoir/Fitzgerald/Banghoff
SHORT TERM...DeVoir/Fitzgerald/Banghoff
LONG TERM...Bowen
AVIATION...DeVoir/NPB
CLIMATE...Evans
Area Forecast Discussion
National Weather Service Dodge City KS
1101 PM CDT Sun Jul 28 2024
.KEY MESSAGES...
- Isolated to widely scattered thunderstorms (15-25%) early this
evening along the I-70 corridor and also possibly (15% or
less) in extreme southwest Kansas. Main hazard will be wind
gusts of 60 to 70 mph.
- Monday through Wednesday high temperatures will range from 102
and 106. Heat index near 105 possible each day, mainly east of
highway 183.
- Monday through Thursday an excessive heat warning is in effect
for Stafford, Pratt and Barber counties. Heat index of 105 to
110 possible along and east of highway 281.
&&
.DISCUSSION...
Issued at 234 PM CDT Sun Jul 28 2024
Earlier this morning, a 500mb high was located near El Paso,
with upper waves evident across the Central Rockies and Four
Corners region. These waves were located on the northern edge of
this 500mb high and near a 300mb jet streak. CAMS are in good
agreement today, taking these upper level waves east northeast
into northern Kansas and Nebraska by late day, which will give
rise to scattered afternoon thunderstorms. What storms that do
develop may even be severe given the forecast 0-6km shear,
cooler mid level temperatures (weak/no CIN), and the location
of a surface boundary ahead of the approaching upper level
trough, mainly north of the I-70 corridor. Further south, the
shear and flow aloft will be weaker as +16C 700mb temperatures
spread eastward into extreme southwest Kansas. These conditions
will limit the chance for late day/evening storms further
south, but at this time am unable to rule out an isolated
evening thunderstorm or two north of a Garden City to Ness City
to La Crosse line based on the locations of a surface boundary
and given that we did have a few elevated thunderstorms earlier
today despite these warm mid level temperatures. The chance for
any storm to develop near or south of the I-70 corridor
currently appears small (<20%). However, if a storm does
develop, it will be capable of producing wind gusts of 60 to 70
mph and hail up to quarters. Another area to monitor this
evening is across extreme southwest Kansas (Morton county
area). Satellite already has afternoon cu developing west of
this area and the latest HRRR does have isolated convection
developing in this area where a surface boundary is currently
located.
As we look ahead to the upcoming work week...Ensemble clusters
today were similar to previous runs moving the 500mb high east
into Texas through midweek and then retrograding this upper high
westward towards the Four Corners region late in the week. This
trend, which all the ensemble clusters have been advertising
for the last several days, will result in a period of extreme
heat early in the week, followed by improving chances for
thunderstorms mid to late week as the upper ridge weakens and
begins to move westward in response to multiple upper waves
crossing the Central Plains.
For Monday and Tuesday, as the 500mb high builds east into
Texas, a period of hot and dry conditions can be expected across
southwest Kansas. NBM guidance has not changed much over the
past several days regarding the forecast highs, and also little
spread in the 10th to 90th percentile have been observed.
Ensembles have remained consistent over the past several runs in
the forecast of the 850-700mb temperatures during the same
timeframe. Given all this, it should be no surprise that the
ECMWF Extreme Forecast Index and Shift of Tails have also been
very consistent in indicating high confidence in an extreme
temperature event. As a result, there is a +80% chance that
temperatures will be 102F or greater during the first half of
the work week, with afternoon heat index values near 105F
possible. With this high confidence on the temperature forecast
on Monday along with good collaboration will go ahead an issue
a heat advisory for areas where heat index values are currently
forecast to be 105 or greater. Along and east of highway 281
this heat will linger into Thursday and given the length of time
this area with have afternoon heat index readings of 105 to 110
plus night time temperatures only falling into the mid to upper
70s will upgrade the excessive heat watch to an excessive heat
warning.
Late Wednesday, all the ensemble clusters are in good agreement
that a more significant upper level trough will cross the
Rockies and move out into the Central Plains. This will not only
weaken the upper high over Kansas and Oklahoma but also allow a
weak cold front to move south out of Nebraska and into Kansas
Wednesday night/early Thursday. The timing of this cold front is
the biggest discrepancy between the ensembles today, but
despite these differences, they are all trending in the same
direction with some cooler air returning.
This upcoming cool down will not be significant based on the
latest ensemble mean 850mb temperature trends, but it will
replace highs in the triple digits early in the week with highs
in the mid to upper 90s in the latter half of the work week.
Additionally, with the upper high retrograding westward, it will
allow for a northwest flow to develop over eastern Colorado and
western Kansas. This will favor ongoing chances for
thunderstorms across southwest Kansas through the end of the
week and possibly into early next weekend.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1111 PM CDT Sun Jul 28 2024
VFR expected through TAF pd. SE/S winds will increase 10-20 kt during
the daylight hours in association with diurnal mechanical mixing
of winds. Winds will abate 5-15 kt by dusk.
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon to 8 PM CDT Monday for KSZ031-046-065-
079-080-088-089.
Excessive Heat Warning from noon Monday to 8 PM CDT Thursday
for KSZ066-081-090.
&&
$$
DISCUSSION...Burgert
AVIATION...Sugden
Forecast Discussion at weather.gov/mqt.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...None.
&&
$$
DISCUSSION...Melde
AVIATION...NLy
MARINE...Melde
Area Forecast Discussion
National Weather Service Des Moines IA
206 PM CDT Sun Jul 28 2024
.KEY MESSAGES...
- Strong to severe storm possible this afternoon into tonight -
main hazard is damaging wind gusts, but hail, a tornado or
two, and locally heavy rainfall are secondary hazards.
- Heat Advisory for southwest into part of south central Iowa
Monday afternoon/early evening as heat and humidity push heat
index values near/above 105 degrees. More widespread heat
headlines probable Tuesday and Wednesday.
- Occasional storm chances with low predictability of timing,
location, and severity generally between Tuesday and late
week.
&&
.DISCUSSION...
Issued at 207 PM CDT Sun Jul 28 2024
Midday GOES-East upper level water vapor imagery shows the mid-level
shortwave trough that is departing the state with a plume of Gulf
moisture preceding it. Back to the west and entering Iowa is the
leftovers of an MCV that tracked across Nebraska and this feature
results in the biggest change to the forecast in the near term. New
TCU development has recently occurred near and west of Sioux City
with storms slowly blossoming in this area. Latest convective
allowing models (CAMs) are not handling the current picture well and
lends itself to lowered confidence. Many CAMs with the exception of
recent HRRR runs show storms maintaining or developing as they move
into western Iowa. How much they intensify into western and our
central Iowa forecast area remains uncertain as warmer air
moves in aloft that may set up a cap, though this may be just
behind the MCV and storms. 1 minute GOES-East Day Cloud Phase
RGB is showing perhaps what may be a north-south line of more
agitated and clumping cumulus nearing the Missouri River and
perhaps what the CAMs are depicting. Ahead of the MCV, latest
SPC mesoanalysis shows 2000-2500 J/kg uncapped of surface based
CAPE (SBCAPE). HRRR soundings at CRL and CSQ show entrainment
CAPE +/-200 J/kg either side of 1000 J/kg so quite a bit less
than the RAP SBCAPE. These HRRR soundings do depict strong low
and moderate mid-level lapse rates along with quite a bit of dry
sub-cloud air that yield downdraft CAPE values between 750-1000
J/kg. Effective shear, particularly higher values of it, will
be arriving with or behind the MCV/storms. So, damaging wind
gusts appear to be the main hazard. Hail cannot be ruled out
given lapse rates, but the freezing level is around 14-15kft
with 1" hail heights around 35kft+ that may limit the hail
hazard. A tornado or two is possible, but will need to locally
back winds and/or increase flow above the surface to elongate
the hodographs and provide better ingest of streamwise
vorticity. This round of storms will track across a portion of
central Iowa through the evening. Their intensity with eastern
extent into central Iowa will likely weaken, but until then some
severe risk may exist over western into perhaps central Iowa.
Right on the heels of the MCV will be the shortwave trough that can
be seen in the GOES imagery over the Dakotas. As this forcing
approaches the state, low level warm air advection will be another
forcing mechanism. This should result in storms dropping into the
state from the northwest around or after midnight, though CAMs are
split in this evolution. The other forcing will be a strengthening
low level jet, though compared to yesterday it is not as far north
and angled less into the state. However, this should kick off storms
in advance of the southeastward dropping storms toward midnight.
While surface based storms are unlikely given the warm wedge aloft,
MUCAPE values around 750J/kg are likely with better deep layer
shear. If storms do exists, particularly with the southeastward
moving storms, then borderline severe hail and gusty winds may
be possible.
On the heavy rainfall side, the parameter space is favorable
for efficient rainfall both tonight as well as this afternoon. Flash
flood guidance shows 6 hour values of at least 2.5 if not 3 inches
while 3 hour values are at 2 inches. Forecast QPF totals from a
variety of deterministic models show isolated pockets of 3 inches
with a few showing storm tracks of 1.5 to 3". 00z HREF localized
probability matched mean (LPMM) shows similar with areas of 2" with
isolated, sub county sized 3" embedded bullseye while the 12z HREF
LPMM is slightly more concerning with a 5"+ bullseye south of the
Des Moines metro, but overall less coverage of heavy rainfall. WPC
initially had a slight risk of excessive rainfall over much of our
area. This seemed a bit aggressive at the time given that our
antecedent conditions have improved with soil moisture capacity
ranging from 50-60% saturated over northern Iowa to 25-50% over
central and southern Iowa and USGS streamflows are at normal or
above normal percentiles on area waterways (versus much above or
high as was the case earlier in July). Thus, was able to coordinate
with WPC on removing slight and maintaining the marginal, which
seems reasonable given that if the rain fell fast enough over an
urbanized area, a flash flood could occur.
All of the storm activity will depart the area by around or shortly
after sunrise across our forecast area. Then, the mid-level ridge
will build back over the region through at least Wednesday, but not
too far poleward with Iowa residing on the northern periphery. Thus,
it will certainly be a hot and humid period, particularly over
southern Iowa. Monday will see heat index values near or top 105
degrees over southwest Iowa. Tuesday and Wednesday look to have more
widespread heat index values over 105 degrees to around 110 degrees
over southern to around Highway 30 or at least I-80. Examining the
experimental HeatRisk, it does bring level 2/orange/moderate into
southern and parts of central Iowa on Monday and then level
3/red/major into southern Iowa Tuesday and more of southern into
parts of central Iowa on Wednesday. So, this brings us to a headline
decision. We debated doing a prolonged advisory through Wednesday
given the heat index values across the south. However, there is a
small reprieve Monday night with lows to around 70 degrees and heat
index values below 75. Then, Tuesday and Wednesday heat index values
in the south are 105+ to around 110 degrees with no overnight
reprieve. Thus, we may need a two day warning there with an advisory
somewhere north of that into central Iowa. Avoiding the confusion of
a double headline (advisory Monday, watch Tuesday/Wednesday),
attempting to keep headlines as simple as possible, and trying to
coordinate as best as possible with neighboring offices, we will
be issuing a heat advisory over a part of our southwestern
forecast area Iowa for Monday afternoon/early evening.
Now, there are two failure modes for the upcoming heat headlines.
One is the high level western US wildfire smoke that will be moving
overhead. This may lower temperatures a few degrees at most and thus
result in heat index values below criteria. The second is with our
proximity to the top of the ridge as there will be multiple low
amplitude shortwaves riding overtop of it. This will bring
occasional storm chances Monday night through at least Wednesday.
Much of the guidance does not show anything Monday night and our
forecast is currently showing less than 15% PoPs, but the 12z
NAM has an MCS barreling southeast through Iowa from South
Dakota while the 0z ECMWF has one dropping through eastern Iowa
out of eastern Minnesota/Wisconsin. There is a more amplified
shortwave trough approaching the area later Wednesday or
Thursday. The GFS continues to advertise a much faster speed
versus the slower CMC and ECMWF. 0z cluster analysis does not
provide much in the way of weighting towards one solution or
another so will stay the course with initial National Blend of
Models. Thus, the higher chances for storms will probably be
Tuesday night through Wednesday night or Thursday depending on
timing. Colorado State University`s machine learning random
forest outlook highlights this period (their day 3 and 4) with
15% severe probabilities. SPC highlights Tuesday night in their
day 3 outlook as well, but stresses the uncertainty and that
this is more of a pattern recognition assigned risk. With
mesoscale details lacking at this point, will need to monitor
severe potential in the upcoming days. Whenever the more
amplified shortwave does pass, it will push down the ridge and
bring an end of the high heat with highs back into mainly the
80s.
&&
.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1247 PM CDT Sun Jul 28 2024
VFR conditions prevail with cumulus popping around FL015 to
FL020 early this afternoon. Biggest change in this cycle is that
storms are now expected to move into the central part of the
state later this afternoon into early this evening over
southern and some portion of central Iowa. As these move out,
another round may arrive from the northwest, but there is quite
a bit of uncertainty in how storm potential may play out. So
have removed TS mention over northern sites later tonight and
have left prolonged SHRA trying to maintain some continuity
given the uncertainty. Lowered ceilings are possible over
northern Iowa Monday morning that may bring ceiling restrictions
for a part of the morning.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Ansorge
AVIATION...Ansorge
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1203 AM EDT Mon Jul 29 2024
.KEY MESSAGES...
- Very warm and humid conditions will prevail through the upcoming
week.
- A stray shower remains possible late tonight, and there is also a
chance of showers and thunderstorms Monday and Tuesday, with
locally heavy rain possible. Mostly dry Wednesday with thunderstorm
chances returning Wednesday Night/Thursday.
&&
.AVIATION...
A band of mid to high level clouds with a few sprinkles during the
evening are the first signs of moisture and instability returning
ahead of Plains low pressure. The 00Z DTX soundings shows a
formidable layer of dry air that held back the evening showers but
which is forecast to moisten considerably during the late night.
This process could result spotty showers spreading back into SE Mi
within the thickening mid cloud pattern. Diurnally disrupted MVFR
clouds across the Ohio valley into into northern IL also expand into
Lower Mi by early morning in a warm frontal fashion signaled also by
surface Td rising toward 70 F. This low level moisture fuels or
sustains from the west additional showers with a thunderstorm also
possible during peak afternoon instability.
For DTW/D21 Convection... Isolated thunderstorms are possible across
D21 and at DTW in the afternoon and Monday evening. A PROB30 is
maintained in this forecast update to account for this, but timing
may last longer into Monday evening.
DTW THRESHOLD PROBABILITIES...
* Low to medium for thunderstorms Monday from 20-24Z.
* Medium for ceilings at or below 5000 ft in the morning and during
late day convection.
&&
.PREV DISCUSSION...
Issued at 357 PM EDT Sun Jul 28 2024
DISCUSSION...
Weather will remain dry the rest of today under mostly clear skies
while daytime mixing heights have aided in daytime highs climbing
well into the 80s this afternoon. Influence of the high pressure
will relent this evening into tomorrow as a negatively tilted mid
level trough lifts out of the Mid-Mississippi Valley. Southerly flow
ahead of this trough will start to draw in more tropical air into
Michigan early tonight. Weak ascent within the theta-e plume tonight
supports at least some low PoPs during the overnight, but better
chances tonight should hold to the southwest.
The dry airmass noted on the 12Z DTX RAOB this morning will give way
to deeper moisture by early tomorrow morning as the main trough axis
reaches southern Lake Michigan. A hot and humid day will be in store
with daytime highs back into the low/mid 80s and dewpoints climbing
to around 70 degrees. PWATs are expected to improve towards to 1.8
inches or greater. Daytime instability will also improve by tomorrow
afternoon with the RAP offering 500-1000 J/kg of MLCAPE, which will
support scattered showers and thunderstorms. Weak shear and weak mid-
level lapse rates will limit potential for organized or severe
thunderstorms. However, the moderate instability and steep low level
lapse rates will support some potential for isolated strong water
loaded downburst winds. The high moisture will also allow for
isolated heavy rainfall.
Will carry PoPs into Monday night, but it will be possible that
activity could be fairly isolated as nocturnal instability develops.
The potential for a shortwave lifting into Michigan along with
continued deep moisture will be the main reason for maintaining PoPs
at this time. Tuesday will be similar, if not slightly better
compared to Monday, in terms of shear and steep mid-level lapse
rates. Instability looks to be slightly greater as another inbound
shortwave arrives within the northwest flow aloft. Organized
thunderstorm activity will again be limited, but isolated strong
downburst winds and heavy rain will be possible Tuesday as well.
Brief period of mostly dry conditions during the day Wednesday as a
surface high pressure and shortwave ridge pass through. Hot and
humid conditions are expected to continue through mid week with
Wednesday pushing towards 90 degrees and dewpoints possibly into the
70s. The next mid/upper level trough moves into the western Great
Lakes on Thursday with good diffluence aloft, improved shear and mid-
level lapse rates, and moderate instability. This set up would be
more supportive of organized thunderstorms across southeast
Michigan. Still time to hash out better details as we approach mid-
week.
MARINE...
Influence of high pressure quickly wanes this evening as a shortwave
currently residing over the northern Ohio Valley/western Great Lakes
advances towards the central lakes. Associated scattered shower and
storm chances are initially confined to the southern Great Lakes and
Saginaw Bay late tonight-early Monday before expanding over the
remainder of the region latter half of Monday through Tuesday with
the arrival of a second system over Lake Superior. This secondary
system drives a weak cold front across the area Tuesday night
bringing a brief break in storm chances. Active pattern is then
reestablished by late Wednesday and looks to continue through the
late week period as another Plains low slowly tracks over the Great
Lakes.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
AVIATION.....BT
DISCUSSION...AA
MARINE.......KDK
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
540 PM MDT Sun Jul 28 2024
...New AVIATION...
.SYNOPSIS...
Issued at 227 PM MDT Sun Jul 28 2024
Shower and storm chances continue through the beginning of this
next week, favoring the mountains and areas along and west of the
Continental Divide. Localized flash flooding and gusty outflow
winds will be the primary threats. Mostly dry and abnormally warm
conditions continue for the Rio Grande Valley and western Texas
through the week.
&&
.DISCUSSION...
Issued at 227 PM MDT Sun Jul 28 2024
Overall, no major changes in the forecast from previous forecast
packages with daily afternoon/evening shower and thunderstorm
chances, focusing over area along and west of the Continental Divide
and the Gila region.
Current water vapor satellite imagery overlayed with 500mb RAP
analysis shows high pressure aloft directly over southern NM and
west TX. At the surface, highest PW values of 1.0-1.3 inches
generally occur areas along the International Border and
southwestern NM, along with dew points in the upper 50s to low 60s.
PW values of less than 1.0 inch for areas north of the I-10
corridor. This sufficient amount of moisture is locked in under the
aforementioned high pressure aloft. With very little shear and
sufficient instability, typical monsoon-like showers and
thunderstorms can be expected this afternoon and evening. Focusing
over the mountains and areas closer to the AZ border.
Orographically influences will get convection started over the
mountains before transitioning to outflow dominated development
during the late afternoon and evening over the lowlands. Coverage
across the lowlands, especially areas along and east of the RGV
will be isolated. Like previous days, the primary threats will be
gusty outflow winds and localized flash flooding. High
temperatures this afternoon will top out in the upper 90s and low
100s across the lowlands.
Upper high and ridge axis will shift further east across central and
eastern TX at the beginning of the week. The corresponding monsoonal
moisture corridor will respond, slowly shifting east across NM.
Fairly consistent weather pattern will setup with daily afternoon
and evening shower and thunderstorm chances areawide, scattered in
the mountains and isolated in the lowlands. High temperatures
through the first half of the week will be in the upper 90s to low
100s across the lowlands, 100-103 for the El Paso metro.
By the end of next work week and into the weekend. Model and
ensemble guidance shows the upper level high reestablishing itself
of the Central Rockies. Above average warmth, along with general
monsoonal type storm activity can be expected.
&&
.AVIATION...
(00Z TAFS)
Issued at 533 PM MDT Sun Jul 28 2024
VFR conditions expected to prevalent through the period with KDMN
having a brief of period of TSRA and possible MVFR from 00Z to
03Z. Afterwards as thunderstorms diminish, all taf sites should
be VFR with sct- broken ceilings at 120-200 kft. Thunderstorms
will redevelop after 18Z tomorrow with scattered storms over the
mountains and ioslated storms possible over the lowlands. Surface
winds not near thunderstorms will be generally northwest at 7 to
10 knots with occasional gusts to 20 knots through the period.
&&
.FIRE WEATHER...
Issued at 227 PM MDT Sun Jul 28 2024
Fire weather concerns remain LOW through the period. Recent
monsoonal moisture surges and rainfall have helped, as ERC values
below 50th percentile at most sites. Weather wise, scattered shower
and storm chances remain in the forecast for the remainder of today
and into next week, with the focus and better coverage for areas
along and west of the Divide and Gila Region. Gusty outflow winds,
lightning, and wetting rains will be the primary impacts.
Temperatures through the period will continue running above the
seasonal average with Min RH values each in the 20-40 percent range
of the high terrain and 17-30 percent range over the lowlands. Winds
will be light and generally diurnal/terrain driven in terms of
direction.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 77 101 79 103 / 40 10 30 10
Sierra Blanca 69 94 69 95 / 30 20 20 20
Las Cruces 73 101 74 101 / 40 10 30 10
Alamogordo 70 99 71 100 / 20 10 20 10
Cloudcroft 54 76 55 77 / 20 40 20 40
Truth or Consequences 71 97 72 96 / 20 20 20 20
Silver City 64 90 64 90 / 50 60 40 60
Deming 71 99 71 99 / 40 20 40 10
Lordsburg 69 95 69 96 / 40 50 50 40
West El Paso Metro 76 99 76 100 / 40 10 30 10
Dell City 71 101 72 102 / 20 10 10 10
Fort Hancock 72 101 73 101 / 40 20 30 20
Loma Linda 69 92 70 93 / 30 20 20 10
Fabens 74 100 74 100 / 40 10 20 10
Santa Teresa 73 98 74 98 / 50 10 40 10
White Sands HQ 74 100 75 99 / 40 20 30 20
Jornada Range 71 99 71 98 / 40 20 30 20
Hatch 71 101 71 101 / 40 20 30 20
Columbus 73 98 73 98 / 50 20 50 10
Orogrande 71 98 71 98 / 30 10 20 10
Mayhill 60 88 59 88 / 20 30 10 30
Mescalero 59 87 59 87 / 20 40 20 40
Timberon 58 86 58 87 / 20 30 20 30
Winston 59 88 59 87 / 30 50 20 50
Hillsboro 67 95 68 95 / 40 40 40 30
Spaceport 68 98 69 98 / 30 20 20 20
Lake Roberts 59 90 60 89 / 50 70 40 70
Hurley 65 94 66 93 / 40 50 30 40
Cliff 64 100 66 100 / 50 60 30 50
Mule Creek 66 92 66 92 / 40 60 40 50
Faywood 66 93 67 93 / 40 40 40 40
Animas 69 95 69 96 / 50 50 60 40
Hachita 69 95 68 95 / 40 40 60 30
Antelope Wells 67 94 66 94 / 60 60 70 50
Cloverdale 64 88 64 89 / 60 70 70 50
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...None.
NM...None.
&&
$$
FORECASTER...04-Lundeen
Area Forecast Discussion
National Weather Service Sioux Falls SD
1046 PM CDT Sun Jul 28 2024
.KEY MESSAGES...
- Scattered strong to severe storms this evening. Greatest
threat is from 7-8 PM to 1 AM with potential for hail up to
hen egg size with initial activity, wind gusts exceeding 70
mph, and a few tornadoes. Locally heavy downpours may bring 2+
inches of rain to a few locations as well. Beyond tonight,
nightly low storm chances continue for portions of the region
through Wednesday night.
- Hot and humid conditions continue through the week. The
highest humidity comes Tuesday and Wednesday, when afternoon
heat index readings near or over 100 degrees are most likely.
- Wildfire smoke aloft will return late tonight-Monday, but
confidence in surface impacts is low. Those who are highly
sensitive to air pollution should monitor air quality
conditions and adjust outdoor plans accordingly.
&&
.DISCUSSION...
Issued at 256 PM CDT Sun Jul 28 2024
THIS AFTERNOON-TONIGHT: Looking at a couple of areas for convection
through the rest of this afternoon and tonight. First will be across
mainly northwest Iowa, as a compact wave/MCV remnants pushes east
across eastern Nebraska/western Iowa. This activity is moving into
an airmass characterized by moderate instability (1500-2000J/kg) and
increasing deep layer shear per the latest RAP projections. While
greater coverage of this activity is expected to be south of Highway
20, will have to monitor our far southeast counties for an isolated
strong to severe storm over the next few hours until this wave moves
east of the area.
Stronger mid-level wave is moving across western South Dakota early
this afternoon and will continue to track east across the eastern
Dakotas into Minnesota through the evening/overnight. Already seeing
spotty storms develop along the associated surface boundary which
extends from western SD into southeast ND. Instability has been
limited in some areas due to morning showers/clouds across our
western counties, but that activity continues to wane, and partial
clearing should allow stronger heating to push MLCAPE values near
2000J/kg ahead of this activity early this evening. Shear starts off
on the weak side this afternoon, but the approaching wave will bring
increasing mid-level winds, with shear increasing accordingly. This
will support organized storms with a threat of large hail with the
initial development. This would be more likely west of our forecast
area, or perhaps just into our northwest corner early this evening.
Storms continue to grow upscale as they progress east this evening,
with the primary threat transitioning to strong/damaging winds,
possibly in excess of 70-75 mph. Exact location of the greatest
threat is still somewhat uncertain, though the high-res models from
this morning are showing better consensus today than at this time
yesterday. This leads to slightly higher confidence that the main
impacts for our forecast area will be near and north of the I-90
corridor, though there is a low-moderate (30-50%) probability of
stronger storms extending south of I-90 toward the Missouri River
after dark. While the primary threats tonight are large hail and
damaging winds, there is a non-zero threat of tornadoes, especially
if bowing segments can become established, as 0-3km shear vectors
would be oriented nearly perpendicular to the lines.
In addition to the aforementioned severe threat, we will have to
monitor for locally heavy rainfall as well. Airmass is primed as has
already been seen with the activity around Sioux City, with Wayne
Nebraska AWOS (KLCG) reporting nearly an inch of rain in 20 minutes.
Precipitable water values exceeding 1.5-1.75 inches are above the
90th percentile of climatology, and while storms will become
increasingly progressive through this evening, any storms which are
slower moving or impact urban areas could present a localized flash
flood threat.
MONDAY-THURSDAY: Tonight`s storms should exit to the east of our
forecast area by daybreak Monday and the daytime hours should remain
rain-free. However, some areas could start the day off with some
patchy fog/stratus in the wake of departing storms. Temperatures may
also be impacted by a return of smoke aloft from western wildfires,
but still looks to be a warm day with highs in the mid 80s to lower
90s. Dew points in the mid 60s-lower 70s will push heat indices into
the 90s in many areas, but at this time it looks to remain shy of
advisory criteria. Speaking of the wildfire smoke, low probability
that we could see some surface impacts on Monday as winds turn to
the northwest behind the departing storms. HRRR Smoke model does
show some increase in near surface smoke, but low confidence in
whether there will be enough to push air quality into a higher level
than Moderate/yellow or reduce visibility.
Tuesday-Wednesday continue to look like the hottest and most humid
days of the week and this would be the period of greater concern for
heat headlines. Barring lingering impacts from isolated-scattered
nighttime storms, trends continue to support highs both days in the
upper 80s to mid 90s, with dew points in the lower-mid 70s, perhaps
upper 70s in a few locations. These values support heat indices
topping 100 in some areas both afternoons, mainly south of I-90.
Various waves sliding across the region in quasi-zonal flow could
bring periodic storm chances, mainly focused during the evening to
overnight hours Monday night through Wednesday night. Strongest of
these waves appears to be Wednesday night and will carry higher and
more widespread chance pops during that period. However, details in
exact timing and location of storms are far from certain. That said,
cannot rule out a few strong to severe storms given unstable mid
level lapse rates and areas of moderate to strong shear.
FRIDAY-SUNDAY: Stronger mid-upper level ridge builds again over the
western CONUS, placing us back in west-northwest flow aloft by this
weekend. This may allow temperatures to ease slightly, though humid
conditions look to continue. Confidence in precipitation chances is
low as any weak waves in the northwest flow could trigger spotty
showers or storms. Unfortunately, this flow pattern aloft will
likely maintain our hazy/smoky skies as we move through the first
weekend in August.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1045 PM CDT Sun Jul 28 2024
Outside of a few isolated showers along/north of the MO River
Valley, latest radar imagery shows largely quiet conditions across
our area. Given how storms have panned out this evening, think any
additional development overnight would remain isolated in nature.
Otherwise, expect light and variable winds to continue for much of
the period. This in combination with a decent amount of moisture in
the lower levels may result in fog prior to/around daybreak. Thus,
could see cigs/vsbys briefly fall to MVFR levels. Any fog
development should burn off quickly though, allowing dry conditions
and mostly sunny skies to prevail Monday.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...JH
AVIATION...SST
Area Forecast Discussion
National Weather Service Glasgow MT
204 PM MDT Sun Jul 28 2024
.DISCUSSION...
KEY MESSAGES:
- More noticeable push of smoke and haze from wildfires across
the Western US will begin moving into the region today.
- Next best chance of rainfall is today, though chances for even
a simple hundredth of accumulation still remain generally under
>40% for most areas. Wetting rain chances are near 0%.
- Fire Weather Watch for Monday is being upgraded to a Red Flag
Warning this afternoon.
WEATHER PATTERN OVERVIEW:
A shortwave moving along the upper-level trough draped across the
western US will bring chances for non-wetting rain for northeast
Montana. SPC currently keeps most of northeast Montana in a
general thunderstorm risk, though the Marginal risk for convection
was expanded across southeast Montana, with fringes of this risk
area in Prairie County. Greatest risk, as has been with the
relatively-drier low-level and limited PWATS, is winds as high as
60 mph. Limiting factor will be any smoke that moves into the
area, inhibiting surface heating and reducing overall instability.
Given that locations will see an increase in RH values, given the
close proximity to sunset, decided to delay the start of the
previously issued Fire Weather Watch from this afternoon to Monday
10 AM MDT. Confidence that the greatest fire risk will fall on
Monday, with westerly winds increasing as RH values dip as low as
10%.
Montana remains in a slight southwesterly/zonal flow through
Tuesday night, at which point, another shortwave moves through.
Given that PWATS will be similar to today`s rainfall chances,
similar non-wetting rain can be expected.
From Wednesday, upper level ridging remains the name of the game
through the long-range forecast.
FORECAST CONFIDENCE & DEVIATIONS:
Felt confident with what the NBM output for PoP through the next
24 hrs. So no deviations were made.
Western wildfires and southwesterly flow will bring in a more
noticeable area of haze and smoke across northeast Montana. The
Canadian Firework (smoke) model, along with the HRRR and RAP13,
show this push today and extending into Monday.
-Enriquez
&&
.AVIATION...
UPDATED: 1930Z
FLIGHT CAT: VFR
DISCUSSION: SMOKE and HAZE from western US wildfires begin to
make a more noticeable move across eastern Montana. This may
result in brief periods of near 6 SM visibility. Rain chances move
through the region throughout the day, briefly bringing reduced
visibility in stronger showers/thunderstorms
SFC WIND: Light and variable. Winds shifting to more southerly
winds this evening, generally under 10 kts. Becoming SW Monday
after sunup. Erratic strong gusts will be possible near any
thunderstorm this afternoon and evening especially near KGDV from
21 to 04Z.
EQUIPMENT: With the KSDY observation sensor being down, have
placed AMD NOT SKED in until it comes back.
-Enriquez/GAH
&&
.GGW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 10 AM to 9 PM MDT Monday for Northern
Valley and Northern Phillips Counties-The Little Rockies-The
Lower Missouri River Breaks including the Charles M Russell
National Wildlife Refuge.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Goodland KS
418 PM MDT Sun Jul 28 2024
.KEY MESSAGES...
- An isolated severe storm is possible this afternoon, mainly
along/north of I-70 in KS-NE between 3-8 PM MDT. Quarter to
golf ball size hail and wind gusts up to 70 mph are the
primary severe weather hazards. Confidence is low with regard
to whether or not storms will develop.
- Monday through Wednesday are forecast to see temperatures in
the 100`s with heat index values also in the 100`s. Locales
generally along and east of Highway 83 could see heat index
values in the mid 100`s Tuesday and Wednesday.
- Not as hot Thursday through Saturday with high temperatures
generally in the upper 90s and lower 100`s. Chance for smoke
to return to the area if wildfires are still ongoing.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 200 PM MDT Sun Jul 28 2024
Overview: Unidirectional /westerly/ flow aloft will prevail
over the Tri-State area today.. downstream of an upper level low
progressing ENE from western Montana to southern Saskatchewan..
and upstream of an upper level low progressing ENE-NE from Iowa
to the Great Lakes.
Current and recent runs of the HRRR and NAM NEST suggest that
strong insolation will aid in the development of isolated
convection in climatologically/ geographically favored locations
in the lee of the Rockies (Cheyenne Ridge, Palmer Divide) by
~21Z this afternoon -- that said convection will intensify as it
progresses east (via ~30 knot westerly steering flow) toward
the CO-KS border ~22Z -- and that an isolated supercell will
emerge from said activity, propagating southeastward along/near
I-70 invof Goodland, Colby and Oakley before dissipating ~00Z.
The HRRR and NAM NEST also suggest that an isolated right-mover
may emerge from convection initiating along/near the Cheyenne
Ridge ~23Z.. and that said right-mover will propagate
southeastward into portions of southwest Nebraska prior to
dissipating ~02Z. Given that convection allowing guidance tends
to be less reliable in weak forcing regimes, confidence remains
below average with regard to whether or not the aforementioned
scenario(s) will materialize / play-out as indicated.
Nevertheless, it must be said that.. recent trends in visible
satellite (e.g. towering Cu in southern Washington/Yuma counties
and along the I-80 corridor from Cheyenne WY to Sidney NE at
1930Z).. lend a fair amount of credibility to convective
initiation as indicated by the HRRR/NAM NEST (timing and
location, at least). Environmental conditions over the Tri-
State area -- characterized by a pronounced elevated mixed layer
(8.5-9.0 C/km H7-H5 lapse rates), modest high-based instability
(~1000 J/kg mlcape), extreme (~2000 J/kg) DCAPE and ~40 knots
of effective deep layer shear (~15-25 KFT AGL) -- are certainly
supportive of isolated supercells.. *if* any updrafts can
survive/overcome a considerable amount of dry air entrainment.
With the above in mind, expect a conditional potential for an
isolated supercell (or two) capable of producing damaging winds
and large hail.
&&
.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 1227 PM MDT Sun Jul 28 2024
This upcoming week through the weekend continues to be forecast to
see hot temperatures and low chances for storms.
Monday and Tuesday remain forecast to see the upper ridge amplify
over the Plains. With this temperatures continue to be forecast in
the 100s with mid to upper 100`s possible on Tuesday. The main
concern/inhibitor is the smoke from wildfires. The smoke from all
the wildfires continues to move across the CONUS and for us as kept
temperatures a few degrees lower than their potential. While the
upper pattern is forecast to try and keep the smoke from the area,
tomorrow may still see enough that temperatures remain in the upper
90`s and low 100`s instead of the mid 100`s (as the 34-35C 850mb
temps would suggest). With the ridge axis over the area, storms are
unlikely both days.
Wednesday & Thursday, a shortwave trough is forecast to move through
the Northern Plains. While not necessarily associated with any cold
air mass, the trough should push the hotter temperatures out of the
area and allow for 90`s and low 100`s. The shortwave trough and
associated surface low should provide some additional lift for
storms, especially on Wednesday. Even with the forcing though, the
overall dry pattern and weak flow look to keep storm chances around
or lower than 30%.
Going into the weekend, an upper trough/low are forecast to deepen
over the Eastern CONUS while the ridge rebuilds over the
Western/Central portions of the CONUS. This will lower the storm
potential back to 10% or less each day. There is still a small
hint that a trough could rotate around the larger low in Eastern
Canada and push through the Plains, providing higher storm
chances and slightly cooler temperatures. However, most ensemble
and deterministic guidance is favoring the ridge dominating
again. The main inhibitor to temperatures climbing back into the
100`s is the northerly flow that is forecast. This would be
similar flow to what brought smoke into the area the past week.
If this occurs, temperatures will likely remain in the 90`s.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 418 PM MDT Sun Jul 28 2024
Both terminals will see mainly VFR conditions through the
forecast period. There is a chance from 00z-03z Monday that
5-6sm with -TSRA.
Winds for KGLD, east around 10-15kts through 03z-04z, then
light/variable. If any storms move to impact the terminal from
00z-03z, then variable gusts 30-45kts are possible.
Winds for KMCK, east around 10kts through 02z, then
light/variable, then east again by 19z Monday. If any storms
move to impact the terminal from 00z-02z, then variable gusts
20-35kts are possible.
&&
.CLIMATE...
Issued at 1200 PM MDT Sun Jul 28 2024
July 29 High Temperature Records (F):
Goodland......104 in 1947
McCook........109 in 1947
Burlington....100 in 2012
Hill City.....108 in 1917
July 30 High Temperature Records (F):
Goodland......106 in 1935
McCook........105 in 2002
Burlington....101 in 2012
Hill City.....109 in 1976
July 31 High Temperature Records (F):
Goodland......105 in 2002
McCook........107 in 2002
Burlington....102 in 2002
Hill City.....113 in 1934
Goodland has the potential for 5 consecutive days of highs of
100+ degrees which would tie it for the 14th longest on record.
Last time this happened was July of 2012.
McCook is also currently forecasted at 5 consecutive days of
100+ degree temperatures which would tie it for 20th all time.
However a few days of overachieving temperatures could put them
in the top 6 all time.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...BV
LONG TERM...KAK
AVIATION...JN
CLIMATE...Trigg
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
840 PM CDT Sun Jul 28 2024
.KEY MESSAGES...
- Daily chances for showers and thunderstorms continue through
Friday, with MCS activity giving the potential for some severe
storms late tonight into Monday morning, and again late Monday
afternoon into Monday evening. There remains periodic risk of
strong to severe storms from Tuesday through Thursday.
- Hot and humid conditions prevail much of this work week over
central and southeast IL. Heat indices approach 100 degrees over
the Illinois River on Monday afternoon. Heat indices are
forecast to reach 100 to 110 during the afternoon and early
evening hours Tuesday through Thursday, with Wednesday likely
being the hottest day.
&&
.UPDATE...
Issued at 840 PM CDT Sun Jul 28 2024
01z/8pm regional VAD wind profilers show an 850mb jet streak
already strengthening to 40kt at MCI. NAM has consistently
suggested a 40-50kt nocturnal jet oriented from Oklahoma
northeastward to southern Iowa by 06z. As the jet cranks up,
clusters of thunderstorms currently across central Iowa will
organize into an MCS, then shift E/SE into central Illinois late
tonight into early Monday morning. With precipitable water values
increasing to 2.00-2.25, the storms will be efficient rain-
producers and may cause localized flash flooding in a few spots.
While the timing and track of the system is still somewhat in
question, confidence is growing that high rainfall rates will
occur...especially along/south of the I-74 corridor between
10z/5am and 14z/9am. Have therefore adjusted PoPs up considerably,
going with a 90-100% chance of thunderstorms during that time
frame. Given antecedent dry conditions, think much of the rain
will soak in...so any flash flooding should be isolated and mainly
confined to urban locations.
Barnes
&&
.DISCUSSION...
Issued at 300 PM CDT Sun Jul 28 2024
Mid afternoon surface analysis shows 1022 mb high pressure over
the Atlantic States with a broad southerly flow of very warm and
moist air on back side of high pressure ridge over IL. Florida
like weather prevailed over central/se IL this afternoon with
temps in the low to mid 80s and tropical like dewpoints in the low
to mid 70s. Heat indices were in the upper 80s to around 90F over
CWA. Radar mosaic shows a band of convection along and just east
of I-57 in eastern IL while a larger area of convection over
eastern MO and approaching the IL border/MS river between St
Louis and Quincy and tracking NE. This convection was forming in
an unstable air mass with MU Capes 2-3k j/kg and ML Capes
1500-2500 j/kg (highest toward MS river valley of western/sw IL)
and weak wind shear ahead of an upper level trof in eastern MO and
mid MS river valley. Moist PW values of 1.4-1.9 inches and highest
near the Wabash river valley where PW near 2 inches. So pockets
of heavy rains with the stronger cells along with gusty winds.
MCS likely to develop by overnight on nose of sw 35-50 kt 850 mb
jet over southeast IA/northeast MO and into west central IL and
track ESE across central IL between 2 am and 10 am Monday. SPC
day 1 outlook has marginal risk of severe storms over west central
IL west of a Galesburg to Jacksonville line primarily for
damaging winds and this marginal risk may be extended further east
with CAMs trending faster with this storm complex. Heavy rains
also a threat with PW values rising above 2 inches over central IL
overnight into Mon morning. Marginal risk of severe storms
continues over rest of central IL during through mid morning
Monday, then another possible MCS with more storms that could
develop late Monday afternoon into Monday evening. Though less
confidence with the 2nd MCS affects on our CWA with CAMs starting
to back off on its convection Monday night over central/se IL.
Highs Monday in the mid to upper 80s with dewpoints in the 70s
giving afternoon heat indices in the mid to upper 90s. Heat
indices will likely top 100F over MS river valley of west central
and sw IL Monday afternoon.
Some more convection could track se over parts of CWA on Tue
afternoon into Tue night with a frontal boundary moving into
central IL on Tue, with best chance in eastern IL and from I-74
north. Highs in the upper 80s and lower 90s Tue (lowest in east
central IL where higher convection chances are) with dewpoints in
the mid to upper 70s giving afternoon heat indices of 99-107F,
highest in southeast IL and from Galesburg to Springfield west.
These areas may eventually need heat advisory Tue afternoon and
has already been issued for areas west and sw of our CWA Tue
afternoon through early Wed evening.
Think Wednesday will be our hottest day as upper level ridge
builds into IL with 500 mb heights rising to 592-595 dm by Wed
afternoon. ECMWF is showing MCS activity sliding se over central
IL Wed afternoon while other models only have isolated convection
around on Wed afternoon. For now we kept lower pops on Wed with
20-30% chance and highest from I-74 north. Highs 90-95F Wed with
dewpoints in the mid to upper 70s and even around 80F possible
with afternoon heat indices 105-112F. Will likely need a head
advisory across much if not all of our CWA on Wed afternoon and
early Wed evening.
Forecast models dig a cutoff upper level low/trof into the upper
MS river valley on Thu. This to drive a cold front se through
central and se IL during Thu night and into southeast IL fri
morning and bring another round of convection. Highs Thu near 90F
northern CWA and mid 90s far southeast IL from highway 50 south
with moist dewpoints in the mid to upper 70s still. Heat indices
Thu afternoon could reach 100-110F, highest south of I-70 and heat
advisory may be needed again especially southern CWA.
Chances of showers/thunderstorms lingers on Friday with upper
level trof/low near central/east central IL and front pushing se
through southeast IL Friday morning. Highs Friday in the mid to
upper 80s central IL and around 90F in southeast IL. Heat indices
could still reach upper 90s to around 100F south of I-70 Fri
afternoon. Have a slight chance of convection in eastern/se IL Fri
evening, then quieter conditions expected for next week as high
pressure settles into the Great Lakes region. Seasonable highs in
the mid to upper 80s Sat/Sunday with dewpoints in the upper
60s/lower 70s, still muggy but not nearly as much as this work
week.
07
&&
.AVIATION... (For the 00z TAFs through 00z Monday Evening)
Issued at 643 PM CDT Sun Jul 28 2024
Widely scattered convection is on the decrease across central
Illinois early this evening, although a stray shower cannot be
ruled out at KPIA/KSPI/KCMI over the next couple of hours. After
that, attention will turn to a cluster of thunderstorms expected
to form on the nose of the nocturnal low-level jet across
Iowa/Missouri after midnight. While there is still some timing
uncertainty, confidence is growing that the storms will shift E/SE
across the heart of central Illinois late tonight into early
Monday morning. Based on the latest HRRR timing, have introduced
thunder at KPIA by 11z...then further east to KCMI by 13z. The
convection will pass to the east of the terminals by 16z, followed
by a period of lingering MVFR ceilings through midday. Ceilings
will scatter from west to east by early afternoon with mostly dry
weather anticipated through 00z Tue.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Indianapolis IN
1055 PM EDT Sun Jul 28 2024
.KEY MESSAGES...
- Chances for showers or a thunderstorm this evening and again on
Monday.
- Daily storm chances continue through Friday, damaging winds
possible Monday/Tuesday
- Heat indices near 100 Wednesday
&&
.FORECAST UPDATE...
Issued at 1055 PM EDT Sun Jul 28 2024
Quick update to revise precipitation probabilities. Upper trough
axis will deamplify and shift northeast. This, coupled with
decreasing instability should limit convective coverage the rest of
the night. The downward trend of remnant convection should continue.
Confidence continues to increase on upstream storms over Iowa
consolidating and moving toward Indiana as an MCS tomorrow morning,
within modest west-northwesterly flow on the back side of
aforementioned trough.
&&
.MESOSCALE UPDATE...
Issued at 910 PM EDT Sun Jul 28 2024
Flooding is likely across portions of Indianapolis urban core, given
impermeable surfaces and heavy rainfall rates from the convective
cluster moving in now. Deep warm cloud layer and warm rain process
is expected supporting 1-2 inch per hour rainfall rates. IND ASOS
has 1/4th mile visibility due to the intensity of the rainfall. A
predictive Flood Advisory was issued to convey the potential for
minor road flooding over the next hour.
All cells across central Indiana will have the potential for heavy
rates. Where upshear growth and training occurs, flooding or flash
flooding will be possible given the unusually moist environment.
Corfidi upshear shows similar cell motion but much slower, hence
training potential. Once cold pools become established as with the
Marion County cluster, more east-northeast and faster forward
propagation will occur. During this transition, we have noted 35-45
mph wind gusts.
&&
.SHORT TERM (This evening through Monday)...
Issued at 234 PM EDT Sun Jul 28 2024
Surface analysis early this afternoon shows a strong area of high
pressure in place over the east coast. A broad area of low pressure
was found over the high plains. This was allowing a southerly flow
of warmer and more humid air into Central Indiana. Aloft water
vapor showed a moderate negatively tilted upper trough over the
middle Mississippi Valley. This was allowing for a tropical plume
of moisture to stream ahead of the trough in KY and IN. Radar this
afternoon shows an areas of showers over NE Indiana exiting from
this plume. Clearer skies over IL have allowed daytime heating to
result in shower and thunderstorm development. These storms look to
be progressing northeast toward Central Indiana Dew points across
the area remained quite moist, in the lower 70s.
Tonight...
Models suggest that the upper trough axis will push east of Indiana
by late this evening. This, along with the loss of daytime heating
will allow for an end for shower and storm chances during the
overnight hours. However, through the evening, chances for showers
and storms will continue to persist ahead of the trough axis. HRRR
continues to show scattered showers and thunderstorms through the
evening. Forecast soundings remain quite saturated through the
evening with pwats approaching 1.90 inches. Thus will use high pops
this evening, but will taper these to lesser values overnight.
Indiana will remain within the warm and humid air mass as southerly
flow persists overnight. As dew points remain in the lower 70s, a
warm night will be expected with lows in the lower to middle 70s.
Meanwhile, an MCS is expected to develop overnight over IA and MO....
Monday...
Another active weather day is expected on Monday. By the morning,
the models suggest that the upper flow will be more zonal. By 12Z,
the HRRR suggests a thunderstorm complex over IL pushing toward
Indiana. The GFS 310K Isentropic surface shows strong lift arriving
ahead of this feature, with plenty of moisture available. Again,
forecast soundings show a nearly saturated column with pwats still
quite high, near 1.90 inches. Thus confidence will be high for
another round of showers and thunderstorms as this wave is expect
pass across Central Indiana through the morning hours. Forecast
soundings by afternoon continue to suggest a favorable column for
convection and as heating by late afternoon leads to CAPE values
expected over 1500 J/KG. HRRR suggests addition thunderstorm
development late in the afternoon. Thus pops will be needed
throughout the day, due to two rounds of showers and storms. The
first round in the morning due to MCS propagation and isentropic
lift, and the second due to afternoon convection due to daytime
heating. Highs should reach the middle to upper 80s.
&&
.LONG TERM (Monday night through Sunday)...
Issued at 234 PM EDT Sun Jul 28 2024
Monday Night Through Wednesday.
A fairly active week is expected with multiple rounds of rain as
ridge riding thunderstorms are expected to impact Indiana. The first
threat for thunderstorms will be late Monday into Monday night with
a weak shortwave pushing southeast from Iowa. While confidence in
the complex is high, confidence is fairly low in the exact timing
and whether this system impacts central Indiana or stays to the
southwest. The next round looks to arrive late Tuesday night into
early Wednesday, but details remain quite uncertain. Each
successive wave will further drop the confidence as these systems
will be heavily impacted by the mesoscale features of the previous
rounds of storms and how they modify the environment. The severe
threat is quite marginal with a combination of unfavorable diurnal
timing and only marginal bulk shear of 10-20kts, but with a well
established cold pool, pockets of strong to damaging winds can`t be
ruled out.
The threat for storms looks a bit lower for Wednesday as the ridge
gradually progresses eastward, but diurnally driven afternoon
convection will be possible. Near Heat Advisory level heat indexes
look likely Wednesday afternoon with expected highs in the low 90s
and dewpoints across south central Indiana in the mid to potentially
upper 70s. This high heat would be dependent on a lack of cloud
debris from Tuesday night convection, so confidence is still fairly
low in dangerous heat levels.
With the potential for multiple rounds of storms, will have to also
keep an eye out for isolated flooding if successive systems impact
the same areas.
Thursday Through Sunday.
There could be additional rounds of storms Thursday into Friday but
this will all be dependent on how the mesoscale environment is
impacted by the storms earlier in the week with low confidence on
even the synoptic environment by Friday as models rapidly diverge.
What does look likely is between Friday and Sunday, a more organized
upper level low should drop southeast from Canada with impacts to
the general Great Lakes Region. Quieter and slightly cooler weather
then looks likely for the weekend as northwesterly flow becomes more
dominant again.
&&
.AVIATION (18Z TAF Issuance)...
Issued at 234 PM EDT Sun Jul 28 2024
Impacts:
- Mainly MVFR this period.
- Scattered showers through early evening. Isolated thunderstorms
possible.
Discussion:
An upper trough will be passing across Indiana and the TAF sites
tonight. A tropical plume of moisture streaming north ahead of the
trough and across Indiana will provide MVFR cigs across the TAF
sites.
HRRR suggests a few waves of showers and thunderstorms this
afternoon, before coverage diminishes overnight. During the
overnight hours the upper trough axis appears to shift to the east
of Indiana and this may limit forcing. Thus due to low confidence
for specific timing, VCSH has been used for much of the afternoon,
with mainly a dry forecast overnight with MVFR CIGS. Time heights
and forecast soundings continue to suggest nearly saturated lower
levels.
HRRR on Monday morning shows an area of thunderstorms arriving
within the now westerly flow aloft. This will be the remnants of a
decaying MCS, expected to arrive from MO and IA. For now, have used
a VCTS mention during the morning hours until more confidence
arrives for precise timing.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...BRB
SHORT TERM...Puma
LONG TERM...White
AVIATION...Puma
Area Forecast Discussion
National Weather Service Lake Charles LA
1039 PM CDT Sun Jul 28 2024
...New UPDATE...
.UPDATE...
Issued at 1018 PM CDT Sun Jul 28 2024
The new pattern is here! Latest 500 mb RAP analysis places high
pressure overtop the northeast GoM; its northwest fringe located
just over the LCH CWA. This high pressure dome will remain in
control, slowly creeping to the west over the next several days.
Hot, humid conditions and very little rainfall can be expected.
No updates were made to the forecast package tonight.
11/Calhoun
&&
.SHORT TERM...
(Tonight through Tuesday night)
Issued at 256 PM CDT Sun Jul 28 2024
Scattered showers and thunderstorms have developed in the past
hour across parts of SW and SC LA, with the activity moving north
into parts of CENLA. This activity should weaken as we get into
the evening hours and be dissipated by 9 to 10 pm.
Expecting less convective coverage on Monday as the high pressure
builds in our region. The best chances for rain will be along the
I-10 corridor, with only a 20 to 30 percent chance. This will
likely be a repeat for Tuesday afternoon.
Temperature-wise, we warm up Monday, and expecting to reach the
heat advisory thresholds of 108 F in parts of central Louisiana.
Later shifts tonight will monitor to see if the heat advisory
coverage area needs to be expanded further.
&&
.LONG TERM...
(Wednesday through next Saturday)
Issued at 256 PM CDT Sun Jul 28 2024
The surface high pressure over the Gulf shifts west during the
long term time frame, so the highest rain chances will be in the
eastern Gulf states. Could see a need for heat advisories in some
places during this time frame.
&&
.AVIATION...
(00Z TAFS)
Issued at 608 PM CDT Sun Jul 28 2024
Mostly VFR conditions are expected through the period, however
patchy lower ceilings may occur at KAEX around sunrise Monday.
Winds will be light and south to southwest.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 74 93 74 95 / 20 20 0 10
LCH 78 90 78 91 / 10 20 0 30
LFT 79 94 79 94 / 30 30 0 50
BPT 78 91 77 92 / 10 20 0 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory from noon to 7 PM CDT Monday for LAZ028-029.
TX...None.
GM...None.
&&
$$
SHORT TERM...15
LONG TERM....15
AVIATION...05
Area Forecast Discussion
National Weather Service Elko NV
1248 PM PDT Sun Jul 28 2024
.SYNOPSIS...Sunny conditions with haze at times due to smoke from
CA wildfires for today and Monday. Visibility may be lower in
Humboldt county being in closer proximity to the fires.
Comfortable afternoon highs in the upper 80`s and lower 90`s on
Sunday will see a slight increase Monday afternoon. Precipitation
and thunderstorm chances are absent from the region through
Thursday night.
&&
.SHORT TERM...Some visibility issues associated with smoke from
nearby CA wildfires will be the main issue in a fairly quiet short
term forecast period. Upper level SW flow presides over the state
between the burgeoning ridge to the southeast and an upper level
trough straddling the Pac NW coast keeps available moisture and
therefore chances for convection away from the CWA in the early
week period. Wildfire smoke will transition mainly across the
northern counties of Nevada Sunday and Monday though Nye and
White Pine county will see some temporary low visibility
conditions from ongoing southern California fires as well. Poor
air quality Sunday and Monday could lead to health related issues
for sensitive groups and precautions should be taken to limit
exposure. Daytime high`s in the 80s and low 90s across the CWA
today will increase slightly into the work week as the
aforementioned ridge continues to build into region Monday and
Tuesday AM.
.LONG TERM...Tuesday through next Sunday. All models show a weak
upper trough moving across the northern Rockies with a large upper
ridge spanning across the southern United States. Moisture and
instability will be limited across the north and could lead to an
isolated dry thunderstorm during the late afternoon hours.
Otherwise, haze and smoke will be prevalent due to wildfires
burning across the western United States. Highs will be in the 80s
and 90s. Winds will be out of the west and southwest with gusts to
25 mph. Look for quiet weather during the overnight though skies
could be haze and smoke filled. Overnight lows will be in the 40s
and 50s.
For Wednesday through Saturday, the large upper level ridge will
gradually move westward and intensify. This means afternoon high
temperatures will climb back to above normal levels. On Wednesday
highs are expected to remain in the 80s and 90s, with warming
conditions into the 90s and low 100s Thursday and Friday. It is
still too far to look at the possibility for heat products though
something may be needed and will keep a watchful eye. Overnight
lows will be in the 50s and 60s. Winds will generally remain
light each afternoon. Model simulations are showing the upper
ridge circulation setting up near the four-corners area on Friday
and Saturday. This will result in a southerly flow that will guide
moisture northward. Because of the rather dry pattern beforehand,
thinking is that most, if not all, storms will be dry on Friday
but a mix of wet and dry storms on Saturday. Will need to keep an
eye on this event as well due to possible fire weather concerns
and dry thunderstorm coverage.
By Sunday, models show the position of the ridge around the states
of Utah and Arizona. This will keep the moist southerly flow going
and believe another round of wet and dry thunderstorms will
develop during the late morning and early afternoon hours. Highs
will be in the 90s to low 100s while overnight lows will be in the
50s and 60s.
&&
.AVIATION...VFR conditions will continue for the next 24 hours for
the forecast area, though temporary MVFR/IFR conditions are
possible due to smoke from California wildfires for the KWMC,
KBAM, KEKO, and KELY terminals. Otherwise, weather conditions
persist across northern and central Nevada. Winds will diminish
this evening but will pick back up Monday W-SW10-15G25KT.
&&
.FIRE WEATHER...Mostly sunny today and Monday with west to
southwest winds of 10 to 20 mph gusting 25 to 30 mph in the
afternoon and early evening hours. HRRR model guidance drifts near
surface smoke over the majority of the CWA today and Monday before
20z when better ventilating SW flow will push some of the smoke to
the northeast away from the region. However, the model has a new
plume of smoke making its way into Humboldt county early Tuesday
morning. Some concerns over fire risk in elevated portions of
White Pine county on Monday afternoon exist due to low RH/wind but
model guidance has winds borderline at best, so criteria is not
present for issuing any products. Partners, however, should
monitor elevated region in the area. Precipitation and thunder
chances are absent from the area through Thursday night. Models
currently have isolated dry thunderstorms across central and
northeastern zones Friday afternoon, however the air is so dry
that the expected weak instability may only result in afternoon
cumulus cloud build- ups.However, better chances for isolated dry
thunder in eastern portions of the region exist Saturday afternoon
with slightly more monsoonal moisture available in those regions.
&&
.LKN Watches/Warnings/Advisories...
None.
&&
$$
99/86/86/99
Area Forecast Discussion
National Weather Service Pocatello ID
250 PM MDT Sun Jul 28 2024
.SHORT TERM...Tonight through Monday Night.
Early afternoon satellite imagery shows a departing H5 trough
over Montana as drier, zonal flow builds in overhead Even with
this drier airmass building in from the west, we will see some
isolated shower and thunderstorm activity primarily along the
Montana and Wyoming border regions associated with lingering
moisture behind yesterdays exiting system. This is where the HREF
model probability of thunder shows a 10-30% chance with less than
a 10% chance elsewhere. Highs today will remain seasonably cool in
the 70s and 80s with wind gusts peaking during the afternoon
hours around 15-30 mph.
For Monday, attention turns to our next H5 trough as it begins to
move onshore to the PacNW while we transition from zonal flow to
carrying a SW component. This will bring highs up into the 80s/90s
across our lower elevations as synoptic winds see an increase
associated with 20-35 kt 700 mb winds shifting overhead. This
will support breezy winds during the afternoon hours with wind
gusts to around 20-40 mph which with a combination of low minimum
humidities in the teens and 20s, will support near critical to
critical fire weather conditions. Ahead of the arrival of this
trough for Tuesday, conditions will remain dry on Monday into
Monday night with isolated showers and storms building into the
CNTRL Mountains early Tuesday morning. MacKay
.LONG TERM...Tuesday through next Sunday.
The long-term portion of our forecast will feature a bi-modal
solution.
First, an organized shortwave trough is well-advertised by all
models to cross the region Tue, bringing isolated to scattered
showers and t-storms and breezy conditions all during the
afternoon and early evening. An early glance at NAMNest and GFS
forecast soundings don`t offer much in the way of support for any
organized severe wx...lapse rates are steep and the low-levels
lean dry which might support some pulse-mode gusty winds, but CAPE
profiles are tall/skinny with DCAPE less than 1,000 J/kg and
zonal westerly flow throughout the column (thus very little
shear). The strongest cores may favor the Central Mountains, due
largely to potentially higher CAPE/instability up in our northern
CWA. We`ll continue digging into all of this in the days ahead.
For now, NBM PoPs seemed a bit low and largely limited to the nrn
Central Mntns and MT border, so increased PoPs and started to
"brush" them further south into the nrn Snake Plain and terrain
areas across the horizontal central 1/3rd of our CWA, a bit closer
to the ECMWF/Canadian solution for where precip may develop.
Hopefully we`ll see this trend natively in NBM guidance as well in
the days ahead. Still, don`t expect a washout anywhere. Expect
high temps Tue to run 5-7 degrees cooler than Mon generally
topping out in the low 80s outside of a few cooler mntn
valleys...this will be 5-10 degrees below climatological normals
for late July and may be another factor that could keep convection
in check Tue afternoon as convective temps still need to be
breached to support t-storm development.
Second (and this isn`t good news if you`ve recently been
struggling with heat and air conditioning issues like this
forecaster)...a large, stagnant dome of high pressure is forecast
by all long-range deterministic models to become re-established
over the Four Corners region for the rest of the week into next
weekend (maybe beyond?), perhaps shifting westward just slightly
with time. This is well- supported by all 500mb height clusters as
well with only slight differences in exact amplitude and axis
position...daily EOF patterns in the ensemble space also reflect
these relatively minor differences with no dominant/consistent
source of uncertainty and no signs of any other dominant wx system
breaking into/breaking down the dome. We`ll certainly watch to
see if any shortwave trough/disturbance riding over the ridge can
flatten it enough to impact SE Idaho...either with wind or a bump
in t-storm potential via broad lift, but otherwise this whole
synoptic pattern spells two things: MORE HEAT, and perhaps an
eventual increase in monsoon moisture working up the back/west
side of the ridge. At this time, NBM guidance supports a warming
trend Wed/Thu with temps stabilizing and maxing out in the upper
90s to low 100s by Fri/Sat/Sun in our normally warmest locales
(ern Magic Valley, Raft River region, Snake Plain, and Challis).
With potentially modest overnight temp recovery, a HEAT ADVISORY
is not completely out of the question for some portion of this
general period, and the ECMWF Extreme Forecast Index (EFI) paints
widespread 0.7 to 0.9 values by Sat and 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 thus confidence is increasing in a heat wave
returning to the region. Long-range models (especially the
higher-resolution Canadian) also show hints of that increasing
monsoon moisture making it up into Idaho as early as Fri, but
especially Sat/Sun. This isn`t yet really reflected in NBM PoPs,
but at least some potential for isolated showers/t-storms should
eventually manifest diurnally each afternoon starting sometime
during this window. At this time, GFS PWATs increase the most
starting Sun but still hold below 1.00", so hard to tell yet
whether or not heavy rainfall will become a concern. Don`t forget
about your heat safety precautions! Overall, didn`t deviate
significantly from NBM guidance and WPC QPF from Wed onward. -
KSmith
&&
.AVIATION...For the 18Z TAFS through 18Z Monday.
Still expecting a diurnal increase in FEW to SCT clouds this
afternoon with some potential for a few isolated t-storms as a
shortwave trough brushes across the region from the north. HREF
CAMs all continue to lean much drier compared to the past several
days, but more than one member develops convection near both KSUN
and KDIJ, so added VCTS to KSUN and adjusted start/end times at
both terminals (18-01z/noon-7pm KSUN and 20-02z/2-8pm KDIJ).
Overall potential is higher at KDIJ compared to KSUN, and we`ll be
keeping a close eye on KIDA as well in case convection tries to
get close to the airport from the north (very low confidence).
Otherwise, expecting a relatively low-impact day as far as
traditional TAF elements are concerned with fairly modest winds
(BUT we`ll talk about wildfire smoke in a moment). Overall
confidence in the wind and cig forecast is high with excellent
agreement among our various models and guidance sources, unless a
t-storm outflow boundary is able to escape into the ern Magic
Valley/Snake Plain corridor and modify wind gusts/direction for a
few hours at KBYI/KIDA/KPIH...this will be monitored in real-time
and captured in an amendment if possible/if needed. Lower PWATs
generally below 0.7", DCAPE over 1,000 J/kg and dry low-levels
advertised in NAMNest/RAP forecast soundings, and a few simulated
gusty outflows on various HRRR runs all suggest outflow boundary
development/propagation is certainly within the realm of
possibility.
The one other likely impact to aviation will be continued
wildfire smoke generally advecting in from the west. Satellite
trends suggest some degree of smoke/haze is already blanketing
most of the state of Idaho from the Snake Plain north/west
(banking up against the terrain south/east of KPIH/KIDA), although
so far this has only manifested in reduced vsbys in the Treasure
and Magic Valley areas (KBYI included...currently running at 6SM).
Forecasting smoke is difficult and overall confidence in exact
numbers is somewhat low...but the general trend on both the HRRR
and RAP smoke models is for smoke to slightly increase over the
course of this afternoon and tonight, and vsbys as low as 3-5SM
have been observed upstream at KMUO and KTWF. Have tried to
capture these general trends in the 18z TAF package with
decreasing vsbys to 5-6 SM over time at KIDA and KPIH, and
potentially as low as 4 SM at KBYI by tonight (based on upstream
obs), while KDIJ may stay more protected by surrounding terrain.
Have held at 6SM for now at KSUN given their nocturnal wind shifts
into the NW which may interrupt transport of the smokier air up-
valley from the ern Magic Valley. All things considered, the smoke
may end up being the #1 aviation concern over the next 24-36
hours for most aircraft. Looking ahead to Mon, expect a dry day
with a slight increase in diurnal afternoon winds out of the WSW,
especially for KSUN and the Snake Plain terminals where gusts of
18- 30kts will likely be needed. - KSmith
&&
.FIRE WEATHER...
The primary impact today will be isolated showers and
thunderstorms along the Montana and Wyoming border regions where
the HREF model probability of thunder shows a 10-30% chance with
less than a 10% chance everywhere else. Have held off on any RFW
issuance at this time given coverage on the latest CAMS has
remained more isolated. Winds gusts today will range from 20-30
mph with afternoon humidity dropping to the teens and 20s.
For Monday, an approaching Pacific trough will move onshore to
the PacNW and help to introduce an increase in winds in addition
to slightly warmer temperatures given increasing SW flow. This
flow regime will support more widespread RHs in the teens with the
coverage of a combination of wind gusts to 25-35 mph and minimum
RHs in the teens supporting a RED FLAG WARNING in effect from 1200
to 2100 for FWZ 410, 475, and 476. Elsewhere, winds and RH will
be more marginal but certainly support near critical fire weather
conditions. Conditions will remain dry on Monday outside of a
5-15% chance of showers and storms along the Montana border
region.
On Tuesday, that aforementioned Pacific trough will pass overhead
and will lead to isolated to scattered showers and thunderstorms
in addition to maintaining elevated wind gusts peaking around
20-40 mph in the afternoon. The more noticeable difference on
Tuesday will be the increase in humidity bottoming out in that
20-40% range during the afternoon hours. Showers and thunderstorms
will depart east Tuesday night as drier conditions build in from
the west as high confidence supports a H5 ridge of high pressure
building in overhead for the remainder of the week. This will
support a return to very dry conditions starting Wednesday as
temperatures see a gradual warming trend through the weekend. We
may see isolated showers and storms building in late next week as
weak monsoon moisture rotates clockwise into SE Idaho but
confidence is low this far out. 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 today into Monday with
increased uncertainty on exactly how much of that smoke will
remain in place on Tuesday as an Pacific trough passes overhead.
Expect continued degraded air quality into Monday 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 (ID DEQ). The current AQI as
of 2 PM MDT Sunday ranges from moderate across to very unhealthy
across all of SRN Idaho with satellite imagery showing widespread
smoke situated overhead. MacKay
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon to 9 PM MDT Monday for IDZ410-475-476.
&&
$$
Area Forecast Discussion
National Weather Service Topeka KS
542 PM CDT Sun Jul 28 2024
.KEY MESSAGES...
-Scattered showers and isolated storms linger this afternoon,
with slight chances continuing overnight.
-Upgraded the Excessive Heat Watch to a Heat Advisory and
Excessive Heat Warning for the upcoming workweek.
-A front will move into the area Thursday, which will provide
some, although not much, temperature relief.
&&
.DISCUSSION...
Issued at 311 PM CDT Sun Jul 28 2024
This afternoon, scattered showers and isolated storms have
continued to develop across the area, appearing to be the result
of continued isentropic ascent. Thinking that this activity
will diminish with time into the late afternoon hours. This
evening and tonight, a weak H5 shortwave trough and associated
PVA will move over Nebraska and northern Kansas within the
westerly mid level flow. Confidence is not high on whether
storms will develop and make it into northern and northeastern
sections of KS, so have trimmed back POPs a little bit more.
CAMs have not been consistent with each other or run-to-run,
lending more to the decreasing confidence levels. The last few
runs of the HRRR have also shown some development in northeast
KS later Monday morning, but with a fairly dry profile, large
amounts of MLCIN and no upper level support, have kept POPs less
than 15 percent.
Attention will then turn to the building heat with upper level
ridging and associated thicknesses increase over the area. Due to
growing confidence, have gone ahead and upgraded the Excessive Heat
Watch that was issued yesterday to a Heat Advisory in far northern
Kansas from Monday afternoon through Wednesday, and to an Excessive
Heat Warning for the rest of the area from Monday afternoon through
Thursday. Actual temperatures are forecast to reach triple digits
much of this time. That combined with dew points in the upper
60s and low 70s will create heat index values between 105 and
112 degrees each afternoon. Boundary layer mixing and occasional
cloud cover could still cause adjustments to the temp/heat
index forecast, but it should be hot enough to satisfy advisory
and warning criteria.
Midweek, a mid-level trough will move through the Midwest, bringing
a cold front into northern KS Wednesday night/early Thursday and
pushing the center of the mid-level ridge westward. POPs increase
near the boundary early Thursday, which is our next best chance for
some precipitation beyond tonight. While Thursday still appears very
warm, especially south of Interstate 70 where the warning will
remain in effect, the front should provide at least some, although
not much, relief for late in the week.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 542 PM CDT Sun Jul 28 2024
Models prog the nose of the low level jet setting up over
northwestern MO. So think the bulk of any elevated storms should
remain northeast of the terminals. There is some indication of
isentropic upglide between 700 and 600MB across central KS
overnight and may be what some of the CAMs are picking up on.
With probs around 20 percent, will keep a dry forecast for now
and watch of indications of the lift developing. VFR conditions
are expected to prevail otherwise. Will maintain some LLWS in
the forecast for a 40KT to 50KT jet and some decoupling of the
boundary layer overnight.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM Monday to 7 PM CDT Wednesday for
KSZ008-KSZ009-KSZ010-KSZ011-KSZ012.
Excessive Heat Warning from 1 PM Monday to 7 PM CDT Thursday
for KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-KSZ034-KSZ035-
KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-
KSZ059.
&&
$$
DISCUSSION...Teefey
AVIATION...Wolters
Area Forecast Discussion
National Weather Service Las Vegas NV
715 PM PDT Sun Jul 28 2024
.SYNOPSIS...Dry and breezy conditions with seasonable temperatures
can be expected through Tuesday. Thereafter monsoon moisture
creeps back into Arizona, returning precipitation chances to
Mohave County midweek. Elsewhere, expect persistent dry conditions
and increasing temperatures heading into the weekend.
&&
.UPDATE...Will update the smoke/haze grids with the latest incoming
HRRR Smoke guidance.
Tonight`s smoke plume from the Borel Fire on a nearly
identical trajectory as last evening. However, magnitude in the amount
of smoke looks to be less. Satellite shows the plume cutting across
Death Valley NP, southern Nye County with leading edge around Indian
Springs. HRRR smoke guidance indicates the worst part of the smoke
plume will stay to the north and west of Las Vegas with a slightly
more southerly trajectory keeping Inyo, Nye and Esmeralda Counties
under the worst air quality. Currently, AQI sensors at Lone Pine and
Keeler CA in the Owens Valley are in the unhealthy and unhealthy for
Sensitive Groups category.
Otherwise, it will stay breezy at times with near normal
temperatures into Tuesday.
&&
.PREV DISCUSSION...1208 PM PDT Sun Jul 28 2024
.DISCUSSION...through next weekend.
Aside from lingering smoke, skies are mostly clear this afternoon
with a broad southwesterly flow aloft keeping conditions dry and
stable. Smoke density overall has trended downward from yesterday,
but we continue to see a layer of smoke induced haze cloud our
skies, particularly across our northern and western zones. This
afternoons visible satellite imagery depicts smoke plumes in Kern
County once again becoming agitated with increasing surface winds
and a deepening mixed layer which will continue to develop
through the daylight hours. This promises additional smoke will
sweep eastward across Inyo, Nye, and Lincoln Counties. A tendency
for increasingly southerly wind components will also help this
smoke drift further west this evening and overnight, impacting the
Owens Valley and Esmeralda County. Alternatively, significantly
less smoke is expected to impact the Las Vegas Valley through
Monday, staying mostly confined to points north and west.
Aside from the smoke, Western US troughing is keeping our region
dry and relatively cool compared to the past several weeks.
Temperatures in Las Vegas are running several degrees cooler than
this time yesterday, and we stand at least a small chance to
break our record ongoing consecutive 105F+ streak. Las Vegas has
so far observed 38 consecutive days of temperatures equal to or
above 105 degrees as of yesterday. The previous record was 25
days in 2017.
The general weather pattern will change little through Tuesday,
with continued afternoon breezes and fairly seasonable
temperatures expected. By midweek onward, high pressure will begin
to rebuild over the Four Corners, setting the stage for a more
typical mid- summer weather pattern and a slow return of monsoonal
moisture to Arizona. Thunderstorm chances creep back into Mohave
County Wednesday onward, while other areas remain dry with a slow
warming trend. There are hints at a weak inverted trough feature
lifting around the high out of southern Arizona and into the
Western Mojave Desert on Thu/Fri, which sometimes can prove to be
a favorable thunderstorm pattern. However, guidance is varied on
both its strength and moisture availability, and NBM pops remain
pretty sparse outside of Mohave county until the weekend. By
Saturday and Sunday, precipitation chances begin to spread west
into the eastern Mojave Desert, while temperatures climb and many
of the lower deserts rise into the major heat risk category.
&&
.AVIATION...For Harry Reid...Breezy southwest winds with occasional
gusts to 25kts will continue into this evening. Winds will diminish
overnight tonight, with speeds likely falling below 10kts by
midnight. Breezy southwest winds will return Monday, although
afternoon gusts should be lower than today, topping out around
20kts. Smoke from wildfires burning in Kern County, CA, will
continue to move across the area today. The smoke is expected to
remain elevated, and no significant reduction in surface
visibilities is expected. However, slantwise visibilities will
likely be reduced, especially in the Beatty and Mormon Mesa
corridors. The latest HRRR smoke guidance shows the plume shifting
further north overnight and Monday, reducing impacts to the Las
Vegas Valley. Otherwise, no operationally significant cloud cover is
expected through Monday.
For the rest of southern Nevada, northwest Arizona and southeast
California... Breezy south to southwest winds with gusts to 25kts
will continue at most regional TAF sites today. All areas should see
winds fall to 12kts or less overnight before increasing to levels
similar to today on Monday. Smoke from wildfires burning in Kern
County, CA, will continue to affect portions of the region today.
Web cameras from across the region show the smoke plume is staying
elevated near regional TAF sites, and the smoke is expected to
remain elevated across most areas into Monday. However, slantwise
visibilities will be reduced, with the largest reductions expected
across northern San Bernardino, central and southern Inyo counties,
and southern Nevada north of the Las Vegas Valley. Otherwise, no
operationally significant cloud cover is expected through Monday.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Pierce
DISCUSSION...Outler
AVIATION...Planz
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