Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/23/24
Area Forecast Discussion
National Weather Service La Crosse WI
1052 PM CDT Mon Jul 22 2024
.KEY MESSAGES...
- Scattered to areas of showers/storm tonight into Tue. Severe
weather not anticipated.
- Trending drier Wed through Sat with warming temps for the weekend.
Sunday could hold the next rain chances after tonight/Tue.
&&
.DISCUSSION...
Issued at 200 PM CDT Mon Jul 22 2024
* TONIGHT/TUE - scattered to areas of showers and storms. Severe
weather not anticipated.
A bit of west-east running shortwave energy currently dropping
across northern MN (per watervapor imagery) at early afternoon,
slated by the short term guidance to continue dropping
south/southeast through tonight. The RAP paints as much as 1500 J/kg
of MUCAPE to work on ahead of the shortwave tonight while also
showing some weak moisture transport. Not much/if any wind shear to
play with. The CAMS spark an area of scattered-broken convection in
response to the lift/instability, with some decrease in areal
coverage/punchiness as we move later into tonight (and lose daytime
heating). The short term guidance does hold at least small rain
chances through the overnight into Tue morning, shifting the
shortwave energy southeast early Tue morning.
However, another bit of shortwave energy is on the heels of the
first feature (also evidenced on watervapor imagery) and is progged
to quickly slide southeast across the region Tue afternoon. Short
term guidance suggesting enough break in cloud cover to re-establish
a pool of instability (2500+ J/kg SBCAPE) for this next shortwave
and accompanying sfc boundary to work on. Shear remains fairly weak
while 850 mb moisture transport runs parallel to the main forcing
mechanisms. CAMS spark more showers/storms for the afternoon/early
evening hours, with a southeastward push. While not looking like a
severe weather setup, instability suggests some perkier storms with
small hail and enhanced wind gusts.
Of note - when there is a break in the clouds, expect smokey skies.
Smoke from fires across Canada progged to work southeast through the
day Tue, per the HRRR. This should stay well a loft and (currently)
not expecting any surface impacts.
* REST OF THE WEEK - trending warmer, drier
Long range guidance is in good agreement with gradually shifting an
upper level ridge east from the west coast, moving the axis across
the upper mississippi river by 00z Sat. All 4 of the WPC clusters
concur with only minor differences in strength/location. High
pressure at the sfc precedes the ridge, sauntering in for the end of
the work week, easing east over the weekend.
The upshot is a shift in the "storm track" eastward after Tue,
favoring a spate of dry days headed into Sat. With the pattern
continuing to advance east, the ridge axis is slated to move over
the eastern Great Lakes Sunday, with southerly fetch of warm/moist
air returning. Some bits of upper level energy could spin out of the
southern branch of the flow and bring rain chances.
Meanwhile, what looks like seasonable temps for the latter half of
the work week should see an uptick for the weekend. Not necessarily
"hot", but both the GEFS and EPS suggest highs back into the upper
80s/around 90 for Sunday.
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1053 PM CDT Mon Jul 22 2024
VFR conditions expected through the TAF period. There is a
chance of fog (30 to 40%) with the higher probabilities north of
I-94. Storms continue to move through western Wisconsin. These
storms will move into central Wisconsin during the early morning
hours. There continues to be a low chance (20 to 30%) of
precipitation occurring during the overnight hours. The better
chance of precipitation will occur during the afternoon and
evening Tuesday as scattered showers and thunderstorms develop
across the area. Winds will mostly be light during the overnight
period, with the one exception being if a shower or storm
passes nearby then gustier winds could occur. Northwesterly
winds will come back Tuesday morning and remain through the TAF
period.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Rieck
AVIATION...Cecava
Area Forecast Discussion
National Weather Service Boise ID
912 PM MDT Mon Jul 22 2024
.DISCUSSION...A couple areas of showers and thunderstorms are
persisting this evening, one crossing from Baker County into
w-central Idaho and the other along the southern OR/ID border.
Expect both areas to gradually dissipate through midnight.
Otherwise will be looking at a mild night, but with less cloud
cover by Tuesday morning, so not as warm as last night. A
northwest wind will transport smoke from fires in e-central
Oregon into SW Idaho overnight bringing a notable increase in
smoke to the lower Snake Plain Tuesday morning though likely not
reaching Twin Falls and Jerome. Have made minor updates to
winds and precipitation chances for this evening.
&&
.AVIATION...Low VFR/MVFR visibility from smoke, with local IFR
in E Oregon. Scattered showers/thunderstorms through 06Z/Tues,
primarily over E Oregon and mtns of SW Idaho. Storms return near
the NV border and in central Idaho after 19Z/Tues, with outflow
gusts of around 25-35 kt. High density altitude due to heat.
Surface winds: variable 10 kt or less, except NW winds in E
Oregon (KBKE/KONO/KBNO) of 10-20 kt with gusts 20-35 kt through
Tues morning. Winds aloft at 10kft MSL: SW-W 5-15 kt.
KBOI...Low VFR in smoke. Smoke will become more dense by early
Tuesday morning with periods of MVFR likely, then gradually
improve Tues afternoon. High density altitude due to heat.
Surface winds: SE 5-10 kt, then SW or variable 3-6 kt beginning
around 10Z/Tues. Then NW 5-10 kt Tues afternoon.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Wednesday night...Fewer
thunderstorms than yesterday later today and this evening
in eastern Oregon, except near the NV border due to monsoon
moisture from the south. Scattered thunderstorms as well
in Owyhee County late today and this evening. Isolated
thunderstorms also this evening in the central Idaho
mountains. Storms will have mainly gusty outflow winds
but little rain. Lesser chance (15 to 25 percent) of
thunderstorms Tuesday afternoon and evening but in the
same areas. Thunderstorms chances will increase Wednesday
afternoon and especially Wednesday night as monsoon moisture
surges strongly northward ahead of an approaching cold front
from the west. This could develop into a thunderstorm
outbreak as the cold front moves in. Storms should also
be wetter, with a 40 to 70 percent chance of measurable
rain reaching the ground even in the valleys. The cold
front will end the current heat wave. Current Excessive
Heat Warnings and Heat Advisories are set to expire
Wednesday evening.
Latest HRRR model spreads significant near-surface smoke
southeastward from the Falls and Durkee Fires in eastern
Oregon this evening, getting into the Treasure Valley late
tonight through Tuesday, except retreating from the Upper
Treasure Valley Tuesday afternoon. Near-surface smoke is also
forecast to overspread all of Harney and Malheur Counties tonight
and Tuesday. Air Quality Advisories have been extended through
Wednesday afternoon in all these areas, and also including Baker
County/OR.
LONG TERM...Thursday through Monday...The cold front should
pass through all zones by Thursday morning taking the
thunderstorms and at least some of the smoke with it. Thursday
will be several degrees cooler and also drier than Wednesday.
The associated upper trough from the Gulf of Alaska will move
inland north of us Friday and Saturday and bring relief from
the heat through at least Sunday. High temps will drop to the
lower to mid 90s in the southern valleys and mainly 80s in the
mountains and north. Low temps will also drop to 55 to 65 in
the southern valleys and 40s to lower 50s in the mountains and
north.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Excessive Heat Warning until 9 PM MDT Wednesday IDZ012-014-033.
Red Flag Warning until midnight MDT tonight IDZ423.
Heat Advisory until 9 PM MDT Wednesday IDZ015-016-029-030.
OR...Excessive Heat Warning until 9 PM MDT /8 PM PDT/ Wednesday
ORZ063-064.
Red Flag Warning until midnight MDT /11 PM PDT/ tonight
ORZ636-637.
Heat Advisory until 8 PM PDT Wednesday ORZ061-062.
&&
$$
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DISCUSSION...DG
AVIATION.....SH
SHORT TERM...LC
LONG TERM....LC
Area Forecast Discussion
National Weather Service Columbia SC
1029 PM EDT Mon Jul 22 2024
.SYNOPSIS...
The chance of showers and thunderstorms continues during the
next several days as a weak and diffuse frontal boundary
persists across the region. The potential for locally heavy
rainfall, which could result in areas of flash flooding and
rising river levels, remains as well. Temperatures will be near
to slightly below through the week.
&&
.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
Key Message(s):
- Isolated showers continue through the evening
Similar to the last couple of nights, convection will persist
late into the evening as lingering outflow boundaries spark
isolated showers. Convection will generally decrease in coverage
through the night but we can`t rule out an isolated shower
through the period. Lows tonight will be in the low to mid 70s.
&&
.SHORT TERM /7 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:
-Hot conditions to continue with max heat indices of 100-105.
-Scattered to likely afternoon/early evening thunderstorms,
greatest coverage in the southeast Midlands.
The pattern will remain stagnant with the upper level trough
west of the region and a very moist air mass over the SE US.
Pwat values will persist in the 2.0 to 2.5 inch range and with
short waves expected to rotate through the base of the trough
scattered to likely showers and thunderstorms will continue
mainly in the afternoon and evening hours. There are an
increasing number of areas across the forecast area which have
received significant rainfall over the past couple days so the
potential for localized flooding will need to be monitored. The
area remains under a marginal risk of excessive rainfall from
WPC. Afternoon high temperatures will be in the low 90s each day
with heat index values generally between 100 and 105.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
KEY MESSAGES:
- Highest chances of showers and thunderstorms Thursday, some
possibly severe.
The upper level pattern will be gradually releasing through the
long term however the potential for afternoon and evening
showers and thunderstorms will continue through Monday. With the
potential for locally heavy rainfall the threat of localized
flooding will remain. Models are in good agreement showing a
strengthening upper ridge aloft Friday through the weekend.
Diurnally driven scattered showers and thunderstorms are
possible each day however models remain a bit aggressive with
the pops and have lowered slightly for the weekend onward.
Temperatures will be near to slightly below normal with
afternoon high temperatures in the mid 80s to around 90.
Ensembles show the ridge breaking down on Monday as an upper trough
passes to the north, potentially resulting in greater rain chances
and cooler temperatures.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Generally VFR conditions expected with some possible
restrictions in convection and early morning stratus.
Persistent scattered showers and isolated thunderstorms continue
to fire across the Midlands with several outflow boundaries
aiding in the persistence. VCSH expected at all terminals except
OGB through around 03z before convection wanes with the loss of
instability. Guidance in not as bullish with predawn stratus as
previous days but HRRR shows a signal in the OGB area 10-14z and
think there could be a period of MVFR stratus after sunrise for
a few hours with mixing. Winds should be light from the south
overnight then pick up from the south to southwest mid morning
Tuesday to around 5 to 7 knots. Possible scattered convection
once again tomorrow but not included in this forecast.
EXTENDED AVIATION OUTLOOK...Showers and thunderstorms possible
each day which may cause brief restrictions. Abundant low-level
moisture may cause early morning restrictions through the end
of the week.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
Area Forecast Discussion
National Weather Service Cheyenne WY
910 PM MDT Mon Jul 22 2024
.KEY MESSAGES...
- Isolated showers and a weak thunderstorms possible this
afternoon and Tuesday afternoon.
- Turning hot and dry on Tuesday through Thursday.
- Quiet end to the week before shower and thunderstorm chances
increased Friday onward.
&&
.UPDATE...
Issued at 907 PM MDT Mon Jul 22 2024
Minor adjustment to forecast grids this evening adding wording
for areas of smoke from tonight through Tuesday and Tuesday
night. Satellite imagery and surface observations reveal a large
area of dense smoke in the mid and upper levels of the
atmosphere. This area of smoke is from widespread wildfires in
Canada and the Pacific Northwest. The current ridge of high
pressure should largely keep most of this smoke in the area for
at least the next 36 hours. Surface concentrations have at times
been high enough to drop visibility to 5 miles or less at
observing sites.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 213 PM MDT Mon Jul 22 2024
Mild temperatures remain present across the forecast region early
this afternoon as our area is feeling the influence of the building
upper level ridge across the Intermountain West. GOES-16 visible
satellite imagery depicts a very large swath of wildfire smoke
propagating from further upstream again today. This has resulted in
lower visibility across portions of the NE Panhandle earlier this
morning, and has limited the daytime high potential this afternoon
because of the pesky haze aloft. Daytime highs are the coolest
across the higher terrain of southeast WY, with warmer temperatures
east of the Laramie Range and the NE Panhandle. The latest HRRR
smoke experimental model depicts the vertically integrated smoke
along the column dissipating close to sunset this evening, but
it will still be present aloft overnight due to the stagnant
weather pattern. Isolated showers will wind down the remainder
of this afternoon into the early evening hours, but severe
weather is not anticipated.
For Tuesday, the upper level ridge centered over the desert
southwest as of 12Z will slowly propagate to the east. As it does
so, it will amplify northward. We can expect WAA to accompany this
feature across our forecast region. 700mb temperatures will begin to
creep upwards beginning Tuesday morning, with +14C to +18C by
Tuesday evening. Clockwise steering flow with the large dome of high
pressure will advect another impulse of monsoon moisture by late
Tuesday. Daytime insolation will create a conditionally unstable
atmosphere. Weak thundershower activity is progged to be present
between 21Z-3Z Tuesday afternoon and evening. The majority of the
atmospheric energy is likely to remain south across the Front Range
of CO, but the Laramie Range should assist with disrupting the main
steering flow in the elevated mixed layer. A few isolated
thunderstorms are anticipated to roll off the higher terrain, but
remain sub-severe. Daytime highs are expected to be in the 80s to
low 90s for the high plains/lower terrain, with slightly cooler
temps in the 60s for the mountain zones. The haze/smoke from
Canadian wildfires is anticipated to linger throughout Tuesday.
Wednesday will be more of the same: above average temperatures and
mostly dry conditions. A few weak thundershowers may crop up by the
late afternoon hours due to conditional instability. Severe weather
isn`t expected however. There may be a slight risk of dry thunder in
the western forecast zones for late Wednesday. The relative humidity
will begin to also be at near-critical thresholds for the region.
Minimum humidity values of 12-20% are likely, and we will need to
monitor the wind speeds in the event that a fire headline is
needed east of the Laramie Range. Expect daytime highs in the
90s to low 100s east of the Laramie Range, with slightly cooler
temperatures west of the Laramie Range. Mild temperatures will
remain through Wednesday night, with lows in the middle 50s to
upper 60s. Isolated areas in the mountain zones above the
nocturnal inversion will dip into the 40s. The general trend is
for temperatures to increase the next couple of days, with a
slow trend of dissipating chances of rain showers.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 200 AM MDT Mon Jul 22 2024
A fairly quiet end to the week as an upper-level ridge will remain
parked over the western CONUS through the week and into the weekend.
Underneath this ridge, 700mb temperatures will rise into the 17-19C
range, leading to a toasty end of the week for much of southeast
Wyoming and western Nebraska. Surface temperatures will creep back
into the low-90s to low-100s area-wide, with the warmest
temperatures expected along the North Platte River Valley and Pine
Ridge. Friday will be slightly cooler than thursday due to the
weakening ridge overhead. temperatures Friday will still be warm, in
the mid-80s to low-100s, with the warmest temperatures along the
Pine Ridge. Precipitation chances look very low for Thursday, with
likely only isolated to widely scattered showers and thunderstorms.
Friday looks like the next best day for precipitation as several
500mb vorticity maxima eject out ahead of an incoming upper-level
trough over the Pacific Northwest. Additionally, a subtle 700mb
shortwave is progged to traverse overhead, which should allow enough
support for more widespread showers and thunderstorms Friday. While
it is still several days out, severe weather is not currently
expected for southeast Wyoming and western Nebraska.
On Saturday, and continuing through the weekend, the upper-level
ridge will begin to flatter out as the upper-level trough over the
Pacific Northwest pushes farther onshore. Quasi-zonal flow will
develop aloft as the ridge is pushed and stretched to the north and
east, while the upper-level trough traverses across northern
Montana. Better jet energy will move in aloft, leading to additional
support for showers and thunderstorms on Saturday and Sunday.
Therefore, expecting daily shower and thunderstorm chances across
the region for Saturday and Sunday, and continuing into the early
work week. Temperatures will remain warm, with highs in the mid-80s
to mid-90s across the region for Saturday, Sunday, and Monday.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 537 PM MDT Mon Jul 22 2024
Main aviation impact for the TAF period will be minor visibility
reductions across the area due to wildfire smoke. Visibility
should remain VFR, with reductions down to 6 SM. Smoke will
linger into the day tomorrow. This evening, a stray shower or
thunderstorm could be possible, but otherwise quiet with light
winds overnight.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...MAC
SHORT TERM...BW
LONG TERM...AM
AVIATION...SF
Area Forecast Discussion
National Weather Service Grand Forks ND
1015 PM CDT Mon Jul 22 2024
.KEY MESSAGES...
- Isolated severe thunderstorms are expected mainly in the
Devils Lake Basin through sunset.
- Mid to upper level smoke is expected to continue occasionally
mixing to the surface. Air quality and visibility could be
impacted at times.
&&
.UPDATE...
Issued at 1015 PM CDT Mon Jul 22 2024
Organized/severe convection had ended, as the front (reinforced
by cold pools from earlier convection) shifted south along with
the mid level wave. There is still enough elevated instability
and forcing to support scattered showers and non severe
thunderstorms mainly in northwest MN and while some guidance has
this ending or shifting over the next few hours, HRRR has
trended towards new development in MN late tonight as yet
another upstream wave rotates through north-northwest flow
through tomorrow morning. High low level moisture (particularly
from recent rain) appears to be supporting fog development in
regions of clearing in our north-northwest, with some smoke
also adding to vis reductions in some areas. CAMs are showing
potential for dense fog development over parts of northeast ND
by Tuesday morning, and this lines up with areas where vis is
already in the 1-3sm range. This update was made to reflect
these trends better for the overnight and Tuesday morning period
a bit better.
UPDATE Issued at 644 PM CDT Mon Jul 22 2024
A mid level wave interacting with a stalled frontal zone helped
organize convection, with a few supercells large hail to 2"
reported. The trend as thunderstorms have pushed south has been
for the severe threat to diminish in the northeast, however as
the wave has pushed south along with the thunderstorm clusters
this has allow the frontal zone to shift and we may still have
a region of effective shear in the 20-25 (close to 30kt) in the
Devils Lake basin near the theta-e gradient/region of higher
MLCAPE (2500-3500 J/KG). New updrafts developing in that region
have the potential through sunset to continue to become severe,
with hail 1-2" the main threat. Higher DCAPE greater than 1000
J/KG in the same areas does raise the potential for isolated
higher gusts with the tallest cores (60-70mph). As conditions
become elevated and the main area of forcing transitions south
we should see a weakening trend in storm intensity.
&&
.DISCUSSION...
Issued at 211 PM CDT Mon Jul 22 2024
...Synopsis...
A weak shortwave has produced some pop up showers
along the International border near Bottineau and some in Pembina
County. Given the environment Cape is going to be around 1500 and
2000 allowing for plenty of energy for storms to consume. However
shear is still 15-20kts which suppresses the likelihood of severe
storms. However gusty winds and small hail can still be produced by
these stronger storms. Most of the cam guidance has the storms
dissipating by 03z but it would surprise me if we had lingering
showers until about midnight or 05z.
Tuesday another wave of vorticity possibly strong enough to produce
storms in the morning is depicted to move across the northern
planes. It`s uncertain if storms will be produced or if the
atmosphere will be stable enough to not lift any moisture. Ridging
starts building in Tuesday evening suppressing any lingering
convection from the morning. With continued northerly flow aloft,
wildfire smoke is expected to persist at various points in the
column to include near-surface smoke. Air quality could be impacted
at times, with upstream observations suggesting minimal impacts to
visibility.
Wednesday through Monday
The ridging pattern builds over the Northern Plains as a Low
pressure starts to move in over British Columbia giving us some
warmer temperatures Wednesday through Monday. with the warmest days
expected to be friday and saturday given most ensembles depict
temperatures in the 90`s. So afternoon convection may occur due to
the area likely to reach convective temperatures but the high
pressure ridge may also suppress the convection. After Saturday the
ridge begins to flatten as the Low pressure system moves across the
Canadian Provinces so temperatures should become more seasonable
come Sunday.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 644 PM CDT Mon Jul 22 2024
Thunderstorm activity (generally isolated to scattered) along
with pockets of near surface wildfire smoke will be the main
aviation impacts this evening across eastern ND and northwest
MN. There are a few stronger/severe thunderstorms that had been
impacting northeast ND and may impact KDVL early in the TAF
period. Expect shower/storms to decrease in coverage after
sunset. Monday morning there is a signal for patchy fog or a few
areas of MVFR (possible IFR) stratus, with the strongest signal
at KDVL and KBJI in the 11-14Z period.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...DJR
DISCUSSION...MM
AVIATION...DJR
Area Forecast Discussion
National Weather Service Grand Junction CO
546 PM MDT Mon Jul 22 2024
.KEY MESSAGES...
- Drier air moving in from the north will confine showers and
storms to the San Juans and along the spine of the Continental
Divide though a stray shower or storm can`t be ruled out over
the surrounding higher terrain.
- Hot temperatures move in for Tuesday through Thursday.
- A push of monsoonal moisture is expected late week, bringing
increasing storm coverage. Some uncertainty remains over how
long this moisture will linger over the area.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 125 PM MDT Mon Jul 22 2024
Visible satellite imagery is showing plenty of cumulus buildup
over the higher terrain this afternoon with some showers and a
few storms noted over the southern valleys and heading up to
Wolf Creek Pass. Exactly as the hi-res models were indicating
yesterday and again today. As one would expect, the highest CAPE
values are in that same area which is also where the PWATs are
highest as well. For the rest of the afternoon and evening the
18Z HRRR continues to show the best chances for convection over
Archuleta county with a few cells popping in La Plata County.
Might see some convection along the spine of the Continental
Divide as well. Suppose we can`t rule out a stray shower or
storm over the remaining higher terrain. Even so, coverage looks
rather sparse and less intense than that seen recently but some
brief heavy rain, and gusty outflow winds can`t be ruled out.
Some very small hail might also make a quick appearance. Outside
of that convection, we`ll see some hazy skies thanks to the
fires up north (including Canada) and warm temperatures. Calm
conditions expected overnight though overnight lows will run on
the warm side of things.
The area of high pressure remains to our west Tuesday as that
northerly flow allows drier air to continue moving in. 0.4 to
0.6 inches of PWAT will remain across the area with a small
sliver of around 0.8 inches for the southern valleys. Guidance
has pulled back on coverage some but for all intents and
purposes, it`ll be very similar to what we see today. Highs will
run about 5 degrees warmer than today for most regions.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 125 PM MDT Mon Jul 22 2024
An amplifying ridge over the Southwest Wednesday will push
temperatures above 100 again here in the Grand Valley and in our low
desert valleys of eastern Utah. Temperatures will trend around 10
degrees over climatology across the region as the tilted ridge axis
builds from the Four Corners into the northern Plains. Thursday and
Friday will see area temperatures back off slightly under the
influence of cloud cover and more rain. A storm working across the
Canadian Rockies will drag a trailing front into the northern
portion of the CWA by Friday. This along with subtropical monsoon
moisture working under the high from the south will enrich the
convective environment on the terrain both Thursday and Friday. The
lingering frontal boundary looks to hang up across our northern
counties on Saturday, while afternoon convection shifts slightly
east on most of our terrain Saturday afternoon. Deterministic
solutions flatten a broad, zonal ridge over the CWA on Sunday, with
some weak orographic showers possible, given enough moisture to work
with. Things look mostly dry as the monsoonal moisture tap gets
shunted south. Models hold on to this pattern for Monday. The
subtropical moisture remains right at our doorstep across Arizona on
Monday. It seems premature at this distance in time to count on a
dry forecast. However, it would be fair to expect a return to
monsoonal flow sometime in the latter hours of this extended period
and beyond.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 545 PM MDT Mon Jul 22 2024
Evening convection, favoring KDRO and KGUC, will wane as the
sun sets. In turn, gusty outflow winds will also weaken as the
surface decouples and drainage winds prevail overnight. Chance
for nocturnal storms remains low, maintaining VFR conditions
through Tuesday morning. Tuesday`s forecast also appears weak,
in terms of afternoon convection, with less than a 10 percent
chance of measurable precip over most terminals. KDRO and KTEX
fall within the 10 to 20 percent range, as the San Juan`s may
tap into the better moisture source rotating across the Desert
Southwest. Thus, gusty outflow winds cannot be ruled out for
southern TAF sites from nearby convection.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...TGR
LONG TERM...LTB
AVIATION...TGJT
Area Forecast Discussion
National Weather Service Goodland KS
811 PM MDT Mon Jul 22 2024
.KEY MESSAGES...
- Storm activity moving out of forecast area this
afternoon/early evening.
- Wildfire smoke continues across the area Tuesday. Some smoke
may reduce visibilities along and west of Highway 25.
- Drier weather and warming temperatures as ridge moves over the
forecast area.
- Storm chances may return this weekend as ridge moves east of
the forecast area.
&&
.UPDATE...
Issued at 749 PM MDT Mon Jul 22 2024
Confidence is increasing in fog development across eastern
portions of the area from around 4am-8am CT. Dense fog may be
possible as well in this area. Further west, fog doesn`t appear
as likely due to more of a westerly wind component.
HRRR Near Surface Smoke has been up-trending on another surge
of smoke moving in from the South Dakota and the Nebraska
Panhandle. From current particulate matter density forecasts,
sites in northern Nebraska and eastern Wyoming are reporting 6
SM in haze; a higher density particulate matter is forecast to
move into the area (along and west of Highway 25) where
visibility in the 4-5 SM due to the smoke/haze seems to be in
the realm of possibility.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 240 PM MDT Mon Jul 22 2024
Latest upper air analysis shows the ridge to the west, centered over
Southern California. To the east the trough over the Plains was
continuing to bring smoke south. Within the northerly flow was an
embedded upper level short wave trough and MCV. The MCV started
scattered thunderstorms over the southeast part of the forecast area
this afternoon.
For the rest of the afternoon the thunderstorm activity will
continue to move south. Once the storm activity currently over the
forecast area exits, am not anticipating on any additional storms.
However, models do have some weak lift over the south so will
continue the chances for rainfall until the sun sets.
Tonight am expecting any storm activity to end as the sun sets.
The upper level flow becomes more laminar as well.
Tuesday the upper level flow continues to look rather laminar.
Individual models, and ensembles, have no rainfall chances for the
forecast area. If there is a lingering surface boundary over the
eastern part of the forecast area, that might serve as a focus for
storm development. However confidence at this time is not high
enough to put in a mention of storm chances.
Tuesday night should be similar to tonight, without the potential
for storm before sunset.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 240 PM MDT Mon Jul 22 2024
The upper level ridge currently west of the forecast area gradually
slides east. As such temperatures will steadily warm and storm
chances will end. Winds are expected to be light and variable.
Toward the end of the week the upper level ridge moves east of the
forecast area. This will allow the upper level flow to become from
the southwest, and allow short wave troughs to move over the
forecast area. Chances for rainfall have fallen for Sunday night,
but remain similar or even increased for Saturday night. The GEFS
and ECMWF ensembles both show little to no potential for
precipitation during this timeframe. The best chance for rainfall
is Saturday night. However this will depend on where the upper
level trough ends up. If the trough is more north of the forecast
area the storm chances will likely shift to the north. Given the
presence of the upper level ridge over the Desert Southwest,
wouldn`t be surprised if the trough ends up being pushed more north.
Highs will continue to warm through the week as the ridge moves
overhead then to the east of the forecast area. The hottest
temperatures look to be early next week when the ridge to the
south builds back over the Plains.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 512 PM MDT Mon Jul 22 2024
VFR conditions are currently forecast to start the period for
each terminal. Mid to upper level haze from fires in Canada
remains across the area resulting in SCT to BKN070-090 across
the area. Will be watching for some potential patchy fog to
develop across eastern and northeast portions of the area
including the KMCK terminal; introduced a tempo to start
introducing the potential but will continue to reassess data
through the evening to see if any flight category reductions may
be needed.
For tomorrow; HRRR Vertically Integrated smoke and even Near
Surface Smoke products are showing another surge of the Canadian
Fire smoke moving into the area. Based on current obs in western
South Dakota showing 6SM with lesser particulate size than what
is forecasted for tomorrow along the CO/KS line has led me to
introduce 5sm visibility restrictions for KGLD due to haze.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
UPDATE...Trigg
SHORT TERM...JTL
LONG TERM...JTL
AVIATION...Trigg
Area Forecast Discussion
National Weather Service Wilmington NC
1030 PM EDT Mon Jul 22 2024
.SYNOPSIS...
Occasional showers and thunderstorms, some with heavy rain,
will continue through the remainder of the week as southerly
winds bring tropical moisture northward. A weak front could
stall near the area this weekend.
&&
.UPDATE...
No major changes with the latest update. Very heavy
showers/storms, especially near Florence, are weakening and
shifting northward. Could see some fog develop late in areas
where it rained recently and higher clouds thin out, especially
inland.
&&
.NEAR TERM /THROUGH TUESDAY/...
Coastal convection has weakened and transitioned to inland
convection. The HREF forecasted this transition well at 00 and
06 UTC. Today`s 12 UTC HREF shows the convection continuing to
move to the north and northwest and weakening before midnight.
The HREF is showing a weak area of convection, mainly along the
coast after 06 UTC to 12 UTC. The HREF is slightly more subdued
during the day, with convection increasing mainly inland by
evening.
One area of concern for heavy rain this evening will be northern
Marlboro County for any significant rain as they experienced
rainfall totals over 6" last night. The HRRR and the HREF are
showing convection over this area after sunset. The GFS
continues to show the southwest flow with weak shortwaves
embedded in the flow. The precipitable water will remain just
above 2" through the foreseeable future. Moderate instability
will continue. So, hopefully, we can see the areas in extreme
drought (Florence County to Columbus County) get some beneficial
rainfall.
Tonight`s lows are expected to be in the mid-70s, and Tuesday`s
high will be around 90, except for the middle 80s at the beaches.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Stacked ridging well off the coast will persist through the period,
and along with a mid/upper trough extending from the upper midwest
to the southern plains, this ensures continued deep SW flow and
abundant moisture across the area. Scattered to occasionally
numerous showers and thunderstorms are anticipated, and should begin
to blossom late morning near the coast, and shift inland through the
afternoon.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Very little significant change to the synoptic pattern is expected
through Thursday as ridge holds over the western Atlantic and mid-
level trough lingers across the upper midwest, therefore the
forecast will be one of persistence. By late Thursday, the
offshore ridge gets suppressed a bit as a shortwave moves across
the Mid-Atlantic states, and Thursday afternoon/evening could
perhaps have the best coverage of showers/storms. Friday into
the weekend, a slow moving frontal boundary may stall across the
area, leading to elevated shower/tstm chances through the
Sunday.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
High confidence in mainly VFR conditions across SE NC/NE SC
through 00Z, although do expect some periods of restrictions in
the form of showers/storms/low clouds and possible fog. The
best chance of restrictions inland at KFLO/KLBT will likely be
tonight and again Tuesday afternoon while near the coast at
KMYR/KCRE/KILM it should be later tonight/early Tuesday and
again late morning to early afternoon Tuesday.
Winds are expected to be south to southwester at less than 10
knots through the period along the coast. Wind speeds will be
less than 4 knots overnight. MVFR vsby and ceiling is possible
at KLBT and KFLO after 08 UTC.
Extended Outlook...Potential for IFR/MVFR with showers and
thunderstorms each day.
&&
.MARINE...
Through Tuesday: The large-scale pattern with the Bermuda High
is well established and will continue for the immediate future.
This synoptic pattern will continue to provide the coastal
waters with south-to-southwest winds between 10 and 15 knots.
Seas will be between 3 and 4 feet through the period.
Monday night through Friday... Bermuda high pressure will hold
through the week, maintaining sustained southerly flow on the
order of 10-15 kt, with occasional gusts to 20 kt. Seas will
remain generally in a 2-4 ft range. A frontal boundary is
expected to approach from the north on Friday. Winds should
lighten up a bit in a weaker gradient along this front. It
appears as though the boundary will stall across the area, but
too early to tell just how far south it will make it. Scattered
to occasionally numerous showers and thunderstorms are possible
through the week, and in the absence of an apparent focusing
mechanism, should generally become more numerous during the
overnight hours.
&&
.TIDES/COASTAL FLOODING...
Minor coastal flooding is expected along the lower Cape Fear
River each of the next several nights during high tide, mainly
due to the recent full moon. Tides along the SE NC and NE SC
coasts are also expected to be close to Coastal Flood Advisory
thresholds through Tuesday.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
NC...Coastal Flood Advisory until 1 AM EDT Tuesday for NCZ107.
SC...None.
MARINE...None.
&&
$$
SYNOPSIS...CRM
UPDATE...ILM
NEAR TERM...RH
SHORT TERM...CRM
LONG TERM...CRM
AVIATION...RJB
MARINE...RH/CRM
TIDES/COASTAL FLOODING...
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
528 PM MDT Mon Jul 22 2024
.KEY MESSAGES...
- Hazy/smoky through at least Tuesday
- Becoming hot/dry with critical fire weather conditions for
parts of the area Thursday/Friday
&&
.DISCUSSION...(This Evening Through Monday)
Issued at 149 PM MDT Mon Jul 22 2024
19z surface analysis had weak high over the CWA. Water vapour
loop had upper ridge from the southwest CONUS to AB/SK, inching
toward the northern Plains. Geocolor loop showed widespread
haze/smoke over large parts of North America with small reductions
in visibility over the CWA this afternoon. 0.5km visible loop
depicted CU over the western 2/3rds of the CWA with TCU trying to
form over the spine of the Black Hills. MLCAPE <1KJ/kg with
minimal cap, so a stray TS possible. Upper support zilch, so
terrain will be main focus for (if) any convection. Main forecast
concern this week is upper ridge.
Tonight through Tuesday, upper ridge builds into the northern
Plains as thermal ridge amplifies. Haze/smoke will persist through
at least Tuesday night with perhaps surface smoke improvement
during the day Tuesday per HRRR smoke guidance. Temperatures will
be near guidance.
Wednesday/Thursday, upper/thermal ridge peaks over the northern
Plains. LREF/NBM portrays 50-90% chance 100F+ MaxTs concentrated
over northeastern WY Wednesday and then over much of the area for
Thursday. Deep boundary layer mixing Thursday will result in gusty
winds at times as well as a chance of high-based thunderstorms
over northeastern WY Thursday night.
Friday, upper ridge breaks down as upper trough moves across
southern Canada. This will allow "cold" front will breach the CWA
later Friday with a chance of TSRA along it and gusty southerly
winds ahead of it. Best chance of 100F+ MaxT east of the Black
Hills, but timing of front will modulate the areas.
Next weekend, southwesterly flow aloft expected with the usual
summertime disturbances bringing chances for thunderstorms.
Temperatures will be near guidance, but still several degrees
above normal given mostly tight ensemble guidance.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening)
Issued At 521 PM MDT Mon Jul 22 2024
Lowered VSBY due to smoke will affect western SD and northeast WY
today. At times VSBY may drop to MVFR. Some improvement is
possible tonight over western South Dakota, but smoke will
generally continue through the rest of the forecast period.
&&
.FIRE WEATHER...
Issued At 149 PM MDT Mon Jul 22 2024
An upper level ridge will bring hot and dry conditions Tuesday
through Friday. As the upper ridge breaks down Friday, a cold
front will slip into the area. The pre-frontal environment
Thursday/Friday will see temperatures in the 90s to around 100 and
very low relative humidities. LREF is giving 70-90% probability
of relative humidity lower than 15% across northeastern WY and
far western SD Thursday afternoon. The pattern favors windy
areas. LREF probability of wind gusts >25mph 50-90% for
northeastern WY and northwestern SD Thursday and 70- 90% for
parts of western SD Friday, particularly over south-central SD.
High-based dry thunderstorms could develop over northeastern
WY Thursday evening. Given the dry/cured fuels, critical fire
weather conditions are likely Thursday and Friday. Relative
humidity Wednesday night and Thursday night will be poor,
especially over the higher terrain of the Black Hills and
northeastern WY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...Dye
FIRE WEATHER...Helgeson