Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/26/24
Area Forecast Discussion
National Weather Service Birmingham AL
727 PM CDT Thu Jul 25 2024
...New SHORT TERM...
.SHORT TERM...
(Tonight through Saturday)
Issued at 726 PM CDT THU JUL 25 2024
Scattered showers will continue for the next few hours across
Central Alabama. A thunderstorm or two can`t be ruled out in the
southeast, as thunderstorm activity is currently ongoing across
southern and southeastern Alabama. Activity should diminish after
sunset, but a stray shower is possible overnight. Have kept in
slight chance PoPs for the overnight and early morning periods.
Foggy conditions may develop overnight, especially across northern
Central Alabama in locations that received rainfall earlier today.
Foggy conditions will improve by mid-morning, and the afternoon will
bring a chance for scattered showers and thunderstorms. Thunderstorm
activity will be more likely in central and southern areas, where
higher instability will be present.
12
Previous short-term discussion:
(This evening through Friday)
Issued at 131 PM CDT THU JUL 25 2024
This afternoon.
A strong elongated ridge extends from over the Desert Southwest
northeast to over the North-Central Plains while a longwave
positive-tilted trough extends from over Southeast Canada
southwest to over the Tennessee Valley Region. Fairly weak/diffuse
low pressure was analyzed at the surface with a low in the lower
levels aloft over Southern Arkansas while surface high pressure
was centered across much of Wisconsin.
RAP 13km mesoanalysis depicts a few shortwaves over Northern
Mississippi and Northwest Alabama. These slow-moving disturbances
aloft in conjunction with a deeply moist vertical profile will
continue to support scattered to numerous showers with a few
thunderstorms with the best potential generally along and north of
Interstate 20. Locally heavy rainfall may result in water ponding
in urban and low-lying areas due to efficient rainfall rates and
slow storm motions. Winds will be from the northwest at 4-8 mph.
High temperatures will range from around 80 far northwest to
around 90 far southeast.
Tonight.
Longwave positive-tilted troughing will persist to our northwest
overnight while more mid-level disturbances will move over
Northern Mississippi northeast over Northwest Alabama and Southern
Tennessee overnight. Strong surface high pressure will be
centered over Michigan with a surface cold front extending from
the Northern Plains southeast across the Midwest and into the
Southern Ohio River Valley Region. Expect scattered showers with a
few storms across the northern quarter of the area overnight with
lower chances elsewhere. Some patchy fog is expected across
portions of the northern and eastern counties before sunrise on
Friday morning. Winds will be from the northwest at 2-4 mph. Low
temperatures will range from around 70 north to the low 70s
southeast.
Friday.
A weakness aloft will persist over the Mid-South and ArkLaTex
regions to our west on Friday while the longwave trough pulls
further away to the northeast. A weak closed mid-level low is
depicted to develop in most guidance solutions where the weakness
aloft is present. Strong surface high pressure will become
centered across the Eastern Great Lakes while the surface cold
front pushes further south, extending from the Northern Plains
southeast across the Mid-South and into Northern Georgia and South
Carolina. Chances for showers and storms will be greater across
the far northern quarter of the area in relative closer proximity
to the front to our north with isolated showers and a few storms
elsewhere. Winds will be from the northwest at 4-8 mph. High
temperatures will range from the mid 80s northwest to the low 90s
southeast.
05
&&
.LONG TERM...
(Friday night through next Wednesday)
Issued at 258 PM CDT THU JUL 25 2024
Daily opportunities for showers and storms continue through the
extended forecast. The Sunday-Monday time frame could offer fairly
high coverage, comparatively, as an upper low/trough translates
across the region, providing additional lift atop an already warm
and moist air mass. This feature will quickly exit, though upper
troughing should be maintained across the eastern CONUS with a
ridge taking shape over the southern Plains. This setup should
result in an upward trend in temperatures and a bit less in the
way of showers and thunderstorms compared to days prior.
89^GSatterwhite
&&
.AVIATION...
(00Z TAFS)
Issued at 639 PM CDT THU JUL 25 2024
VFR conditions this evening at all sites, with occasional showers
at BHM. MVFR cigs and vis will set in after sunset at BHM, EET,
TCL, ANB, and ASN, likely dropping to IFR overnight into the early
morning. Conditions should improve after sunrise, although MVFR
cigs may hold on until closer to midday. MGM should stay VFR
overnight, although a brief drop to MVFR in possible but not
explicitly mentioned. Scattered thunderstorms are possible
tomorrow afternoon, with a PROB30 for thunder in at BHM, EET, TCL,
and MGM.
AMD NOT SKED for TCL currently as the ob is intermittent.
12
&&
.FIRE WEATHER...
Fire weather elements are not expected to reach critical
thresholds over the next several days. Regional showers and
thunderstorms continue each day, varied in coverage, with high RHs
and light 20-foot winds.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 69 87 69 89 / 50 40 10 60
Anniston 69 86 71 89 / 50 40 10 60
Birmingham 71 86 71 90 / 50 40 10 60
Tuscaloosa 70 87 72 91 / 50 40 10 60
Calera 69 86 72 89 / 50 40 10 60
Auburn 71 89 73 88 / 40 40 10 60
Montgomery 72 91 73 91 / 30 40 10 60
Troy 72 91 71 91 / 30 40 10 70
&&
.BMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...12
LONG TERM....89^GSatterwhite
AVIATION...12
Area Forecast Discussion
National Weather Service Denver/Boulder CO
713 PM MDT Thu Jul 25 2024
.KEY MESSAGES...
- Scattered showers in the mountains this evening. Numerous
showers and thunderstorms for the mountains Friday and Saturday,
with scattered storms on the plains.
- Elevated fire weather conditions are expected over the higher
terrain on Sunday due to hot, dry, and windy conditions.
- Trend towards hot and dry continues late weekend into next week.
- A few daily records tied or broken is very feasible with the
upcoming heat as we broach the triple digits again.
&&
.UPDATE...
Issued at 704 PM MDT Thu Jul 25 2024
Showers are starting to move into the central and northern
mountains from the west at this hour as moisture increases. With
diurnal heating going away, these should diminish over the next
few hours, then there is a break in the moisture before more comes
late tonight or early Friday morning.
Updated forecasts for more clouds over the mountains and shower
timing. Also dropping the Red Flag Warning now, since conditions
are easing.
&&
.SHORT TERM /Through Friday/...
Issued at 234 PM MDT Thu Jul 25 2024
It`s another hot day for northern Colorado today as an upper-level
ridging pattern continues. Northerly flow aloft persists continuing
to bring hazy skies to the Front Range from wildfires burning to our
north. The ridge is expected to continue to elongate to the
northeast bringing a more westerly regime aloft to Colorado for
tomorrow. This will begin to push the more concentrated smoke levels
to our east. The latest loop of the HRRR Vertically Integrated Smoke
guidance clearly depicts this expected trend and shows some
potential relief beginning as early as this afternoon with
significant improvements overnight. This outdoor enthusiast welcomes
some relief!
With regards to precipitation for today, instability is lacking
across the plains as portrayed by forecast soundings showing minimal
CAPE values between 50-300 J/kg throughout the afternoon and
evening. Large dewpoint depressions show dry lower levels with DALR
extending up past the 600 mb level. Forecast soundings show a
slightly different story for the higher elevations with marginal
instability indicated with SBCAPE values ranging from 500-900 J/kg.
PWAT values look to increase throughout the day reaching around .71"
by this afternoon. This could support the development of isolated
showers/storms later on this afternoon and evening.
With 700 mb temperatures ranging from 15 to 20C today, surface
temperatures have surpassed the 90 degree mark with some locations
aiming for 100 degrees across the plains. With these hot and dry
conditions in place, critical fire weather has become a concern. We
have issued a Red Flag Warning for portions of the plains that will
continue through 9 PM this evening.
Tomorrow will bring increased chances for precipitation with
periods of heavy rainfall possible across the mountains as
increasing moisture and instability are expected. PWAT values will
climb into the 1-1.25" range putting us above 75% of normal
(.84"). This could lead to areas of flooding associated with the
strongest storms, especially over our burn scar locations. See
hydro section below for more details. These showers and storms
will likely move eastward across the plains bringing some gusty
outflows with them, however, instability is modest and with dry
lower-levels, chances for heavy rainfall over the lower elevations
are low. The most impact expected over the plains would likely be
from dissipating storms causing gusty winds as they enter the more
stable environment. Temperatures are expected to be in the 90s
across the plains once more, with the higher elevations expected
to be in the 70s.
&&
.LONG TERM /Friday night through Thursday/...
Issued at 234 PM MDT Thu Jul 25 2024
The assignment if you choose to accept it, we highly encourage you
to do so, beat the heat and stay hydrated. Even as our average daily
highs have reached the 90F threshold for late July and early August,
the incoming heat is nothing to balk at. We typically average 3
100+F degree days along the Front Range over the past 10 years and
we`ve already hit that average in mid-July. The prolonged nature of
the 100F or near 100F has been the bigger concern and Sunday through
Wednesday of next week is showing consistency to be another stretch
of well above normal summer heat. Ensemble guidance, even though
coarse, is showing greater than a 60% chance we exceed 99F over a 3
to 4 day stretch from the Front Range urban corridor to the far
northeast plains.
Outside of the heat the next best chance (about 25%), and we use
that term very lightly, for rain would be next Thursday as moisture
continues to increase a bit with a shortwave trough of low pressure
nearing the region. Much of the activity may remain tied to the
higher terrain, typical, and lower temperatures a few degrees
elsewhere with more cloud cover, but that is really about it at this
time.
&&
.AVIATION /00Z TAFS through 00Z Saturday/...
Issued at 704 PM MDT Thu Jul 25 2024
VFR through Friday. South winds gusting to around 25 knots will
continue at KDEN/KAPA this evening, becoming lighter and more
southwesterly by 12z. A period of lighter west winds is expected
for a few hours Friday morning, then winds will become north to
northeast. Scattered showers and thunderstorms are expected Friday
afternoon. A few periods of gusty winds are expected, with west
directions preferred but some variability possible. Gusts up to 35
knots are likely, with localized gusts to 45 knots possible. This
threat is mainly between 21z and 24z Friday.
&&
.FIRE WEATHER...
Issued at 234 PM MDT Thu Jul 25 2024
With hot, dry, and windy conditions expected across portions of
the plains this afternoon, a RFW has been issued for FZ242-245
from 1 PM this afternoon through 9 PM this evening. Relative
humidity is expected to drop as low as 11% and wind gusts up to 35
mph are possible. Elevated fire weather conditions are also
expected outside of these zones included in the RFW including the
eastern portion of FZ238, and the western portions of FZ248 and
249.
&&
.HYDROLOGY...
Issued at 234 PM MDT Thu Jul 25 2024
Increased moisture is expected to enter the forecast area on
Friday. PWATs are expected to be above normal (~1-1.25"),
increasing concerns for localized heavy rainfall over the
mountains. Areas of most concern will be our burn scar locations.
Timing of likeliest impacts will be from noon into the evening
hours.
Enough moisture will remain across the region on Saturday for
scattered showers and thunderstorms and provide a minimal impact to
the area burn scars. Beyond Saturday, the pattern dries out and
warms up several more degrees.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Gimmestad
SHORT TERM...Bonner
LONG TERM...Heavener
AVIATION...Gimmestad
FIRE WEATHER...Bonner
HYDROLOGY...Bonner/Heavener
Area Forecast Discussion
National Weather Service Grand Forks ND
1024 PM CDT Thu Jul 25 2024
.KEY MESSAGES...
- Heat concerns into the weekend, with heat indices getting into the
upper 90s and low 100s in the Red River Valley Friday.
- There is a level 1 out of 5 risk for severe weather Friday and
Saturday. All modes of severe weather are possible.
&&
.UPDATE...
Issued at 1022 PM CDT Thu Jul 25 2024
Temperatures will continue to slowly fall overnight tonight but
only modest heat recovery is expected thanks to high dew points.
No weather impacts are expected overnight.
UPDATE
Issued at 855 PM CDT Thu Jul 25 2024
The heat advisory will expire at 9 PM CDT as sunset should push
apparent temperatures below 75 F. Impacts should be minimal
overnight tonight.
UPDATE
Issued at 616 PM CDT Thu Jul 25 2024
Skies remain clear outside of the smoke aloft still making
things hazy. ?Upstream higher clouds are starting to filter into
the Devils Lake Basin tied to a pretty stout upper wave. This
should be the only cloud cover tonight as this low will progress
northeastward. Heat will continue to be the biggest issue with
limited recovery expected overnight.
&&
.DISCUSSION...
Issued at 239 PM CDT Thu Jul 25 2024
...Synopsis...
Satellite this afternoon looking fairly clear, with some clouds to
our west and the faint tinge of smoke aloft. Canadian wildfire smoke
continues to be an issue in the FA, mainly for sensitive groups. A
brief reprieve from the smoke is indicated in the RAP tomorrow as a
front comes through, but the smoke quickly fills back in aloft.
After another front Saturday night, the temperature trend will be
more in the mid 80s initially, then looking to warm back up into mid-
week next week into the 90s. The weather pattern continues to look
unsettled into the next work week, as the UL flow is more zonal.
...Heat Concerns...
With dewpoints into the 70s in the Red River Valley Friday, Heat
indices are forecasted to be in the upper 90s along and north of HWY
200 and in the low 100s south of HWY 200. Because of this, and an
accompanying wet-bulb globe temperatures in the 80s, a heat advisory
is in effect for Friday afternoon and evening. With WBGT that high,
outdoor exercise should be postponed in the hottest parts of the
day. Make sure you are staying hydrated and taking frequent breaks
in the A/C or shade. As you move out of the RRV counties (either
east or west), the probability for high heat indices begins to
decrease. Seeing some indication that areas into northern Minnesota
could have heat concerns Friday, but my confidence in that is less
than in the Red River Valley.
...Severe Start To The Weekend...
Tomorrow and Saturday, SPC has parts of our area under a marginal
risk (1/5) for severe weather. Tomorrow`s risk is better instability
ahead of a cold front, but the shear is more marginal for supercell
development. A few isolated supercells could develop early, and all
modes of severe weather will be possible with those discrete cells
including damaging winds up to 60 MPH, large hail up to half dollar
sized, and an isolated tornado. As a jet kicks in into the evening,
this looks to support more linear organization into the overnight
period. This will transition the major threat to damaging winds
overnight. Saturday`s set up is similar, but more uncertainty exists
in terms of timing and if the atmosphere can rebound from Friday`s
severe threat.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 1022 PM CDT Thu Jul 25 2024
Low level wind shear will continue overnight tonight for most
TAF sites. Conditions should improve after sunset. VFR
conditions should prevail for the TAF period, although VFR
impacts to visibility from smoke are expected. Isolated MVFR
visibility cannot be ruled out as a result. Winds will remain
elevated through the day tomorrow. Showers and thunderstorms may
develop in the vicinity of TVF/GFK although confidence remains
very low in impacts to the TAF sites. Storms may also be capable
of hail if they do impact the TAF site.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Heat Advisory from noon to 9 PM CDT Friday for NDZ008-016-027-
030-039-049-052-053.
MN...Heat Advisory from noon to 9 PM CDT Friday for MNZ001>004-007-
029.
&&
$$
UPDATE...Perroux
DISCUSSION...AH
AVIATION...Perroux
Area Forecast Discussion
National Weather Service Spokane WA
338 PM PDT Thu Jul 25 2024
.SYNOPSIS...
Gusty winds and dry weather will mean lingering fire weather
concerns this evening, before things start to improve later
this evening into Friday. However smoke from regional wildfires
may impact some of your activities. The weekend will be dry with
seasonably warm weather. The arrival of a slow moving frontal
system Monday and Tuesday will bring the chance for showers and
thunderstorms. Above average temperatures and dry weather will
likely return toward the end of next week.
&&
.DISCUSSION...
This afternoon through Friday night: An upper trough will continue
to migrate across the region this evening, before the region
starts to shift into a more benign regime for Friday. Tonight that
upper trough and moisture caught up in it will continue to provide
some scattered to broken cloud cover over the northern CWA, with a
some embedded showers over the northeast WA and north ID counties
before about 7-8 PM. Then the clouds and showers collapsing with
sunset. Winds will remain breezy this afternoon, sustained near
10-20 mph with gusts near 25-35 mph. Regional RH values are
starting to bottom our in the upper teens to lower 20s. The winds
will start to abate with sunset and RHs will start to recover. Red
Flag Warnings remain in effect for portions of eastern and central
WA, including around the Colville Reservation around the Swawilla
Wildfire.
Friday itself will be a bit warmer than today, but still a bit
below normal. Clouds will be more limited and transient too and
winds will be lighter. However with active wildfires surrounding
much of the Pacific Northwest from Canada to California, including
some very active ones in our own CWA, the region will have to
contend with smoke and haze. HRRR models continue hold some of the
denser smoke around the Cascades and northern counties, as well
as over the far southeast CWA early this evening. However heading
into the overnight and Friday that smoke and haze is forecast to
expand over more of the Columbia Basin and eastern Washington.
This includes the Spokane/CdA area. It linger throughout much of
the day into Friday night, even into Saturday though by then model
start to shift the focus more over Idaho, back over the Cascades
and toward the southern third of WA. So keeping an eye on air
quality is something to keep in mind, looking to sources as such
airnow.gov or local resources. /Solveig
Saturday to Thursday: Saturday will feature elevated fire weather
conditions in central Washington thanks to weak troughing and a
marine layer in western Washington. Wind speeds of 10 to 15 mph
with gusts to 25 mph will be common across the Columbia Basin,
West Plains, and Palouse during the afternoons Saturday and
Sunday. Typical evening winds through the Cascade gaps will
deliver gusts up to 30 mph to Wenatchee, Vantage, and Waterville.
The ensembles show a 10-30% chance of reaching Red flag thresholds
in central Washington Saturday and even into eastern Washington
on Sunday.
Monday and Tuesday: A trough offshore the WA coast Monday will
increase our precipitable water and shower chances in the Inland
Northwest. The latest National blend of models shows a 10-30%
chance of measurable precipitation for the Columbia Basin, L-C
valley, Palouse, and north Idaho through Tuesday night. There is a
30-70% chance of measurable precipitation near the Cascade crest,
Pasayten Wilderness, and northern mountains of Washington through
Tuesday night. There does not appear to be a great amount of
destabilization during this period so widespread lightning
activity is not expected at this time.
Wednesday onward: Models suggest a return of strengthening
ridging in the NW US with warmer temperatures. With a gulf of
Alaska trough in place, winds will be a daily concern. /Butler
&&
.AVIATION...
00Z TAFS: VFR conditions will prevail for the period. Winds will
taper this evening. HRRR smoke indicates MVFR conditions possible
for KGEG-KCOE but confidence is not high enough to put in the TAF.
FORECAST CONFIDENCE AND/OR ALTERNATE
SCENARIOS: There is low confidence on how smoke will impact
visibility across the Inland Northwest. Lighter winds Thursday
evening may allow visibility reductions to increase in coverage.
-----------------------
Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70
percent chance
High - Greater than a 70 percent chance
For additional probabilistic information for NWS Spokane airports,
please refer to the Aviation Dashboard on our webpage:
https:/www.weather.gov/otx/avndashboard
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 83 54 87 57 86 / 0 0 0 0 0 0
Coeur d`Alene 48 81 51 84 54 83 / 0 0 0 0 0 0
Pullman 44 79 47 81 50 81 / 0 0 0 0 0 0
Lewiston 56 89 59 91 62 91 / 0 0 0 0 0 0
Colville 40 81 44 84 46 84 / 10 0 0 0 0 0
Sandpoint 43 78 47 81 50 81 / 20 0 0 0 0 0
Kellogg 52 77 56 81 57 80 / 0 0 0 0 0 0
Moses Lake 49 85 52 88 55 89 / 0 0 0 0 0 0
Wenatchee 55 86 60 89 61 88 / 0 0 0 0 0 0
Omak 50 89 57 91 59 91 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Red Flag Warning until 9 PM PDT this evening for Colville
Reservation (Zone 702)-Eastern Columbia Basin -Palouse -
Spokane Area (Zone 708)-Lower Palouse -Snake River (Zone
709)-Okanogan Valley (Zone 703)-Waterville Plateau (Zone
706).
&&
$$
Area Forecast Discussion
National Weather Service Pendleton OR
705 PM PDT Thu Jul 25 2024
.UPDATE...Limited weather concerns outside air quality in the
near/short term. Latest satellite shows multiple local/regional
wildfires on the landscape impacting air quality. Notably, the
Retreat wildfire west of Yakima, which has been reducing
visibilities at KYKM to sub-6SM throughout today, is no longer
impacting there visibility. Latest VWP shows winds have shifted
sufficiently to the northwest to push the smoke south/away from
KYKM. Otherwise, clear skies besides lofted smoke and updated the
Wx for smoke transport based on the latest HRRR and satellite
trends. Latest thinking is after tonight smoke will be transported
more widely eastward across parts of eastern OR and south central
WA tomorrow based on latest forecasts (confidence 60-80%).
Otherwise, highs will be commonly 5 to 10 degrees warmer than
today, however, some added uncertainty exists for daytime temps
owing to the potential for smoke aloft to affect highs.
&&
.PREV DISCUSSION... /issued 446 PM PDT Thu Jul 25 2024/
SHORT TERM...Today through Saturday...Area fires continues to
impact air quality and visibility, notably the Retreat fire
upstream of Yakima that has reduced visibilities to sub-5SM.
Otherwise, mostly clear skies outside of smoke from fires on the
landscape. Otherwise, main concerns are winds today.
A dry northwesterly flow is in place with a shortwave trough
across the region through the forecast period, driven by the low
over BC area. Breezy winds and cool near-normal temperatures will
be the highlights for the next few days. Today, moderate wind
gusts will occur across the eastern Columbia Gorge, Kittitas
valley, and the Cascade Gaps around 25-35 mph. However, higher
gusts possible at Kittitas Valley, as seen with gusts up to 45 mph
this morning. However, chances for these gusts are low now (40-60%
chance) owing to a reduced pressure gradient. The surface
pressure gradient initially started off pretty strong but is
decreasing now and will continue through the afternoon. Wind
conditions should decrease to light around 10 mph or less starting
around tonight.
Friday through Saturday, mid to high clouds will move across the
Columbia Basin and Yakima valley including portions of the WA
Cascades. This is supported by HREF (70% confidence). Winds will
then continue being light as the low and shortwave trough moves to
the east. Temperatures will be in the 70s and 80s through Friday,
but are expected to steadily increase for Saturday into the 90s
in the Basin and upper 80s elsewhere. Thus a return to seasonable
temperatures Saturday. Dry conditions will persist with low
relative humidity in the teens to lower 20s. Feaster/97
LONG TERM...Saturday through Thursday. Broad mid-level troughing
with cyclonic flow anticipated to be in place early Saturday.
Meanwhile, a closed upper-low is anticipated to be downstream in
Saskatchewan/Manitoba with a lingering ridge well upstream in the
eastern North Pacific. Ensemble guidance is in fair agreement
with the large scale pattern evolution through Monday followed by
increasing spread in guidance. The lower confidence/increased
spread could be attributed to potential embedded disturbance(s)
revolving around the mean troughing prevailing over the PacNW
coast Monday/Tuesday, and secondarily the downstream
amplification of a building ridge over the Rockies and High
Plains. Ensemble guidance show excellent agreement initially with
a broad mid-level trough and seasonable high temperatures to begin
the long term period with a general westerly flow aloft through
the weekend. A modest synoptically imposed pressure cross-Cascade
pressure gradient will support breezy conditions in the afternoon
and evening Saturday and Sunday. While not unusual, anticipated
our windy climo-proned areas of the Cascade gaps, Kittitas
Valley, eastern Columbia Gorge spilling into the OR Lower Basin to
see breezy conditions. This is buttressed by high chances of
breezy conditions, NBM 24-hr probabilities of max daily gusts
exceeding 40 mph over 60%, Saturday across the aforementioned
areas with similar chances seen on Sunday. Timing wise, should be
afternoon-evening period with highest winds then lessening
overnight.
Increasing moisture will be seen moving northward ahead of a
disturbance with this starting on Monday, along with a slight
uptick in highs compared to the weekend. There will also be the
potential for isolated-scattered showers starting as early as
Monday along the Cascade crest. Of which, clustering scenarios are
showing appreciable differences in timing with this upcoming
deepening shortwave trough between Monday and Tuesday. Lower
confidence in the timing of the shortwave trough affecting the
region on Monday (~30-40%) based on clustering scenarios.
Increasing confidence in the disturbance affecting the area
Tuesday (70%). That said, instability appears somewhat marginal in
tandem with weak mid-level lapse rates. Chances for thunderstorms
are low (less than 15%) Monday and Tuesday but bears monitoring.
Current thinking is the risk area for thunderstorms is highest
across the central OR Cascades to central mountains OR to eastern
OR mountains with the better, though low, chances existing on
Tuesday. Thus some elevated fire concerns exist with the potential
for new starts from dry thunderstorms.
The central CONUS upper-level ridge is projected to strengthen and
shift slightly westward with a warming trend taking hold mid week.
Highs are forecast to be 8-12 degrees above normal by Thursday.
While there is some uncertainty in terms of weak, passing open
waves on the western periphery of the ridge and the overall
amplitude of the upper-level ridge, fair and dry conditions look
to prevail more likely than not mid-week (70-90% confidence).
AVIATION...00Z TAFs. Aviation concerns continue to revolve around
impacts from wildfire smoke and some limited wind concerns the
remainder of the afternoon/evening. Retreat fire in Yakima county
continue to impacts flight categories at KYKM while most other
TAF terminals see little-no impact besides haze. Otherwise, mostly
clear skies, except for aforementioned wildfire smoke. Recent
PIREPs show tops of smoke around 90 kft.
Current thinking remains intact with a more favorable wind direction
anticipated to take hold in the next few hours that should promote
improved conditions at KYKM. Latest KPDT VWP has shown a more
northerly component being gained over the last three hours and
believe this will provided the needed push to transport the smoke
south of the terminal between 00-03 UTC. Increased confidence in
this outcome owing to the latest HRRR forecasts as well (~80%).
Otherwise, breezy winds continue continue with gusts up to 30 kts,
highest at KDLS. Winds will lessen starting around 00 UTC / 5 PM PDT
overnight with sustained winds anticipated to be less than or equal
to 5-7 kts early morning. Light winds expected tomorrow (under 10
kts).
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 48 84 51 86 / 0 0 0 0
ALW 51 87 54 89 / 0 0 0 0
PSC 54 87 55 90 / 0 0 0 0
YKM 48 87 53 89 / 0 0 0 0
HRI 50 88 54 90 / 0 0 0 0
ELN 48 87 54 88 / 0 0 0 0
RDM 42 84 47 84 / 0 0 0 0
LGD 46 85 49 85 / 0 0 0 0
GCD 48 89 52 87 / 0 0 0 0
DLS 54 89 58 85 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
SHORT TERM...97
LONG TERM....80
AVIATION...80
Area Forecast Discussion
National Weather Service Pocatello ID
111 PM MDT Thu Jul 25 2024
.SHORT TERM...Tonight and Friday. Showers and thunderstorms are
increasing early this afternoon, and will progress north and east
through tonight. Many storms will produce little rain, but like
yesterday...we will see plenty of storms with a decent burst of
rain and gusty winds. There is a 50-90% chance of winds over 40
mph across a good chunk of eastern Idaho this evening, with some
low end potential for gusts near 60 mph. A MARGINAL RISK for
severe weather is still in place outside of the central mountains,
but we wouldn`t be surprised to strong outflow winds anywhere
across our area. Thunderstorm potential decreases but still NOT
ZERO overnight as storms shift east. We will see more storms
tomorrow, although coverage is more limited and mainly across
higher elevations along the Montana border...as well as the South
Hills/Albion Mountains, southeast and eastern highlands. The
potential for wind gusts is lower, only 30-70% over 35 mph and not
really any signal for gusts closer t0 60 mph. Outside of storms,
it will be breezy...especially across the central mountains and
and Snake Plain/Magic Valley. We are looking at any wind-related
headlines at the moment. For tomorrow night, we will already see
the next round of showers and potential overnight storms lifting
northeast out of Utah. Keyes
.LONG TERM...Saturday through next Thursday.
This weekend will feature the coolest temperatures we have seen
since early July with highs each day in the 70s and 80s across our
lower elevations. We will keep our daily isolated to scattered
thunderstorm chances going through Saturday as a H5 shortwave trough
lifts north out of the Great Basin, helping to introduce a 20-70%
chance of showers and storms throughout the day with best chances
across the Snake Plain south into Utah/Nevada and east into Wyoming.
Following that shortwave trough, SW flow will be reintroduced over
the area and will limit any shower and thunderstorm coverage to
around a 10-30% chance along the Montana and Wyoming border regions.
With predominant SW flow remaining in place for early next week,
temperatures will remain seasonable under the increasing influence
of high pressure overhead. By midweek next week, temperatures look
to respond to a H5 ridge axis shifting overhead which will bring
temperatures back to above normal levels with highs reaching the 90s
to low 100s. Very dry air moving onshore from the Pacific at this
time looks to keep the bulk of monsoon moisture south of Idaho
through the work week next week which will also lead to breezy winds
peaking each afternoon. By next weekend, long range model guidance
supports the potential return to more shower and thunderstorm
potential as a H5 trough in the NE Pacific moves onshore to WRN
Canada. MacKay
&&
.AVIATION...Predominant VFR and dry conditions will continue early this
afternoon ahead of a cold front passing overhead later this
afternoon and evening. This front will support isolated to scattered
showers and thunderstorms regionwide with a 60-90% chance at KPIH
and KBYI with a 40-60% chance at KIDA, KSUN, and KDIJ. Stronger
storms will be capable of producing MVFR/IFR VIS with heavy rain and
wind gusts in excess of 30-40 kts. Outside of convection, winds will
remain elevated this afternoon with gusts to around 20-25 kts.
Following this cold front today, breezy winds will help to introduce
a drier airmass into place for Friday in addition to increased
wildfire smoke from regional wildfires to our west. The latest HRRR
smoke model shows visibility dropping at KBYI early Friday morning
and to a lesser extent at other terminals as a mix of near-surface
smoke and smoke aloft build into southeast Idaho. For tomorrow,
expect some lingering shows and storms primarily SE of the Snake
Plain where a 30-60% chance of thunderstorms exists with less than a
10 percent chance up towards the CNTRL Mountains. MacKay
&&
.FIRE WEATHER...We will continue with RED FLAG WARNINGS through
this evening for all zones EXCEPT for Zone 422. Thunderstorm
coverage will be highest outside of the central mountains, where
the warnings for Zone 475/476 are more for wind/RH but does
include the potential for some thunderstorm development. There is
a 50-90% chance of wind gusts over 40 mph over a broad area of
central and eastern Idaho. There is a decent signal as well for
gusts close to 60 mph, so we will be watching for that. Wetting
rain potential is higher down south, with the best chance across
Zone 427 where chances are in the 30-60% range. Chances are in the
30-40% range across the Magic Valley (425) and from Pocatello
south and east (413) through this evening. Elsewhere they are
ranging anywhere from almost zero to 25-ish percent. Showers and
isolated thunderstorms will linger overnight generally along and
east of I-15. For Thursday, we will see another round of storms
across higher elevations outside of the central mountains. There
IS an area of isolated storms possible from Borah northeast toward
Gilmore Summit and Lone Pine during the afternoon. Coverage looks
limited enough to preclude any RED FLAG WARNINGs for thunderstorms
tomorrow. The potential for gusts is around 35 mph and down a bit
to 30-70%, and really no signal for gusts near 60 mph. Wetting
rain chances are down to 15-30% at best and mainly near the
Montana border. Wind gusts do look similar (maybe slightly weaker
in some spots) to today across the central mountains and Snake
Plain. We will issue a RED FLAG WARNING at some point this
afternoon or evening for Zones 410, 422, 475 and 476 for winds and
low humidity. Saturday has the potential to be another RED FLAG
day due to thunderstorms especially across Zone 476 and the rest
of eastern Idaho away from the central mountains. We will need to
monitor trends as there is some concern that early showers and
storms may complicate (in a good way) the potential for higher
coverage of lightning. Wetting rain and gust potential goes up
again on the flip side. After we see lingering storms near the
Montana border Sunday, we are back to warmer weather and dry
conditions. Keyes
&&
.AIR QUALITY...Air quality is in the good to moderate range across
the area. However the 00z run of the HRRR smoke model shows a strong
push of smoke moving through the Treasure Valley into the Magic
Valley and Snake Plain Friday. Visibility could reduce to 5 to 10
miles and we could see deteriorating air quality on Friday.
13
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 10 PM MDT this evening for IDZ410-411-413-
425-427-475-476.
Red Flag Warning from Noon Saturday until 10 PM MDT for
IDZ410-422-475-476.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
451 PM MST Thu Jul 25 2024
.UPDATE...Updated 00z Aviation Discussion.
&&
.SYNOPSIS...
Another active weather day is anticipated across south central
Arizona with the potential for strong to severe thunderstorms
this afternoon and evening. The main threats will be gusty outflow
winds, dense blowing dust, and locally heavy rainfall.
Thunderstorm chances will decrease heading into the weekend with
rain chances remaining confined to higher terrain areas. There
will be a slight cooling and drying trend that will allow for the
excessive heat conditions across southeast California to come to
an end after Friday. Rain chances increase again across the state
by the early to middle part of next week.
&&
.DISCUSSION...
The latest RAP analysis showed the subtropical ridge of high
pressure centered over central Arizona this morning with 12Z RAOBs
recording 500 mb heights around 599-600 dm across the state. The
strong ridge will lead to continued above normal temperatures with
some places seeing highs this afternoon a degree or two warmer than
yesterday. Temperatures across the lower deserts will generally top
out in the 110-115 degree range with the warmest temperatures
focused along and west of the Lower Colorado River Valley.
Additionally, dew points in the 60-70 degree range will help boost
heat indices in excess of 120 degrees in some places across
southeast California to the Lower Colorado River Valley today. Major
to Extreme HeatRisk will be present in the aforementioned areas
today and tomorrow where an Excessive Heat Warning remains in effect
through Friday evening.
Visible satellite imagery showed mostly clear skies across the
lower deserts, allowing for plenty of sunshine, while widespread
convection is ongoing across the northern high terrain. The ridge
will gradually shift southwestward today, providing north to
northeast flow aloft over south-central Arizona. Embedded in this
flow along the periphery of the ridge will be a weak perturbation
that will arrive later today and thus may provide some upper
support to aid thunderstorm development going through the
afternoon and evening. The 12Z HREF shows MUCAPE values once again
climbing upwards of 1000-1500 J/kg today. Favorable thermodynamics
combined with forecast soundings showing favorable inverted-V
profiles and DCAPE values upwards of 1500 J/kg will promote robust
convection across parts of south-central Arizona capable of
producing strong to severe downbursts. Strong outflows emanating
from these thunderstorms and any outflow collisions will help to
initiate additional development into the lower deserts heading
into this evening. HREF paintball plots indicate thunderstorms
surviving into the Valley while chances quickly drop off going
into southwest Arizona and southeast California. However, there is
some uncertainty in terms of thunderstorm coverage given last
night`s thunderstorm activity across portions of central and
western Phoenix. There is better confidence that eastern parts of
the Valley will stand the better chances for seeing thunderstorms
later this afternoon and evening given the lack of activity there
last night. Nonetheless, folks should be prepared for the
potential for more strong to severe thunderstorms across the
Valley with damaging winds being the primary threat. SPC has
highlighted a good chunk of the area in a Marginal Risk for
damaging winds. In addition to the wind threat, outflows in dust
prone areas may lead to areas of dense blowing dust, which can
quickly lead to hazardous travel conditions. The weaker storm
motion combined with sufficient moisture to promote locally heavy
rainfall may lead to isolated instances of flash flooding.
.PREVIOUS DISCUSSION...
There is still good agreement amongst ensemble guidance regarding
the upper ridge becoming displaced farther south towards the
international border beginning Friday. This pattern shift will
result in drier W to NW steering flow setting in across forecast
area. Thus PoPs will drop to near zero across the western half of
the area Friday afternoon. However, there will still be enough mid-
lvl moisture present across the eastern half of the forecast area
for storm chances to linger. Currently PoPs range from around 20-30%
in the Phoenix Metro to around 50-60% in S Gila County Friday
afternoon/evening. There will not be much change in regards to mid-
lvl hghts/thickness on Friday with 850 mb temps remaining around 30-
31C, therefore high temps will still remain unseasonably hot for
most of the forecast area, especially across the western deserts.
Further suppression of the upper ridge is expected this weekend
which will result in a noticeable drop in moisture levels. As a
result, a decrease in monsoonal thunderstorm activity is likely,
with activity mostly confined to far eastern and southeast portions
of AZ for Saturday and Sunday. Temperatures will also cool by a few
degrees as hghts aloft diminish overhead. Highs this weekend will
largely below 110F, especially by Sunday. Heading into next week,
the ensemble members indicate that the subtropical ridge will
quickly rebound and build back over the Four Corners region. The GFS
and ECMWF deterministic model solutions still indicate an inverted
trough or easterly wave arriving by Tue-Wed next week which could
bring an uptick in monsoonal activity across the southern half of
AZ. With the strengthening of the upper lvl ridge, we will also
see a slight increase in temperatures throughout the week.
&&
.AVIATION...Updated at 2350Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The primary weather impacts will be strong, gusty outflow winds
with abrupt wind shifts and scattered TS around the PHX airspace
into this evening. Strong storms near Wickenburg have sent an
outflow from the northwest that will reach at least KPHX and KDVT
before a stronger outflow out of the E-NE between 0030-0130Z is
expected to sweep the terminals. Somewhat better confidence
exists that more concentrated storms will develop closer to KIWA,
however direct impacts with MVFR thresholds may occur at any
location though probabilities are under 30%. Thus, have largely
kept VCTS mention given the most probable coverage.
With additional storms likely south and east of terminals through the
evening, wind directions and speeds will become more uncertain,
however enough evidence exists to include a brief period of gusty
southerly winds as outflows possibly surge back north. Should this
outflow become stronger than anticipated, a period of blowing dust
(either at the sfc or lofted) could conceivably drift north into
the metro mid evening, though confidence is too low to include in
this TAF package. Otherwise, east winds should finally settle over
the area after midnight though it would not be out of the question
for brief period of variability to persist until sunrise. West
winds should reestablish between 18-20Z tomorrow across the
terminals before another period tomorrow evening where gusty
outflows become a concern again. With less thunderstorm coverage
anticipated over the high terrain to the north and east tomorrow,
certainty in an outflow sweeping the TAF sites is too low and
would be just beyond the current forecast period.
Southeast California/Southwest Arizona including KIPL and KBLH:
No major weather issues will exist through Friday afternoon under
a few mid/high cloud decks. Winds will generally favor some amount
of a southerly component, though a period of westerly sundowner
winds are likely at KIPL. A surge of gusty south winds is also
possible for a period overnight at KBLH though overall confidence is
rather low.
&&
.FIRE WEATHER...
Scattered showers and thunderstorms are expected to develop across
southcentral AZ again this afternoon and evening. Some storms could
become strong to severe with the primary threats being strong and
erratic outflow winds, locally heavy rainfall, and frequent
lightning which could cause new fire starts. Thunderstorm chances
will begin to diminish starting Friday and remain confined to the
higher terrain this weekend. Outside of any convection, winds will
follow typical diurnal upslope/downvalley patterns with intermittent
gusts in the 15-20 mph range during the afternoon. Min RHs will
mostly range from 15-25% through Friday with sub 10% RH developing
across the western districts Saturday and Sunday. Overnight Max
RHs tonight will range generally from 40-60% before dropping to
around 25-55% overnight Saturday morning for most places. Max RHs
across the southern Gila County high terrain will be around
60-70%.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST Friday for AZZ530-532.
CA...Excessive Heat Warning until 8 PM PDT Friday for CAZ560>570.
&&
$$
DISCUSSION...Smith
PREVIOUS DISCUSSION...Salerno
AVIATION...Whittock/18
FIRE WEATHER...Smith/Salerno
Area Forecast Discussion
National Weather Service Raleigh NC
930 PM EDT Thu Jul 25 2024
.SYNOPSIS...
A cold front over the Ohio Valley will approach the region Friday.
The front will settle south of the region Friday night, bringing
drier and cooler conditions for the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 930 PM Thursday...
* Flood Watch cancelled for all but Anson and Richmond Counties
tonight
* Flood Watch remains in effect for the Sandhills and Coastal Plain
on Friday
The majority of the heavy rain has pushed south and east of our
area. The main batch of rain is along far eastern sections of NC. A
surface cold front as of 9 pm is largely situated across the lower
OH valley in KY/WV and sections of northern VA. With time, this
front is forecast to reach northern sections of central NC by early
Fri morning. Aloft and at low-levels, there remains an area of
moisture convergence and lift along and south of the front.
Satellite imagery reveals new convection showing up over central SC
in combination with the aforementioned ingredients and also mid-
level support/energy. Most areas north of US-64 will be dry for the
remainder of the night. However, with the front to our northwest and
a subtle surface trough draped along the US-1 corridor, additional
showers or embedded storms could reform for the southern Piedmont,
Sandhills and southern Coastal Plain after midnight into early Fri.
The last few runs of the HRRR show a potential MCV from convection
in SC bringing this activity into these areas for the overnight
hours. Additional rainfall amounts could range from 0.25 to 0.75
inches, highest in the southern Coastal Plain. As a result, we
decided to keep the Flood Watch in effect for Anson and Richmond.
Some patchy fog is possible across our northern zones, along/north
of US-64, where patchy clearing skies will allow for saturation.
Overnight lows should be in the upper 60s N to low 70s S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 335 PM Thursday...
Fri will be our last wet day in this stretch, focused mainly on our
southeast sections, followed by mostly dry weather Sat.
Fri/Fri night: The surface cold front is expected to push SE into
central NC by Fri morning, propelled by high pressure centered over
the Great Lakes and by mid level shortwave troughing from the
Canadian Maritimes through the Ohio Valley and mid Miss Valley to E
TX. Ahead of the front, high chance for showers and storms will
continue for one more day in areas S and E of the Triangle, where PW
is expected to remain over 2" beneath a stream of mid level
perturbations riding atop the area and within the right upper jet
entrance region. The heaviest rain is likely to be focused over and
just inland from coastal sections where sea breeze convergence could
augment large scale ascent, and given the chance for multiple storms
clusters to propagate into our SE Fri, yielding a risk for
torrential rainfall, will extend the SE portion of the flash flood
watch out in time, through 7 pm Fri. Pops will be chance or lower
from the Triangle to the N and W where PWs will be falling post-
front with the gradual onset of weak subsidence heading into Fri
night. Expect highs in the low-mid 80s, with lows in the 60s to
around 70.
Sat/Sat night: The surface high will extend into the area as the
front settles just to our S and SE, resulting in northeasterly low
level flow with falling PWs to near 1". The mid level trough axis
will still be SW-to-NE oriented across central NC Sat morning, and
before this finally pushes to our SE, there will be a chance for a
few showers and an isolated storm over our far SE, but this risk too
should be waning by late afternoon. Expect fair to mostly clear
skies for Sat evening/night, with falling dewpoints into the 60s, a
welcome break from the humidity of late. Highs should again be in
the low-mid 80s with decent sunshine, followed by lows in the low to
mid 60s. -GIH
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 250 PM Thursday...
Sunday will start with an omega block over the area - a weak upper
low will be over the northern Plains, an upper low will be southeast
of New England, and an upper ridge will extend south from Lake Erie
down into the Carolinas. However, the offshore low will drift
northwest over New England while the Plains low weakens into a
trough, and soon the upper level pattern will return to what it has
been much of this past week - a nearly stationary trough to the west
of the area which will bring a continued chance of rain. However,
with precipitable water values forecast to be closer to normal than
they have been this week, rain should not be nearly as widespread or
intense. Highs will be a couple degrees below normal at the start of
the period, mostly in the 80s, rising to near normal Wednesday and
Thursday, in the upper 80s and lower 90s.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 750 PM Thursday...
24 hour TAF period: While confidence is high sub-VFR cigs will
redevelop overnight, timing could be off a couple/few hours at some
terminals. The axis of showers/storms should stay east of KRDU, and
possibly KRWI, with KFAY being the most likely site where they may
linger into tonight. MVFR/IFR cigs should spread across central NC
after midnight, with KINT potentially hanging onto VFR cigs longest.
Cigs should continue lowering to IFR/LIFR after 06Z, (isolated
pockets of VLIFR possible, but confidence of occurrence at a
specific terminal is low at this time) and prevail through early Fri
morning. While vsbys should generally be MVFR overnight, some patchy
fog across the north could result in pockets of lower vsbys. Slow
improvement to VFR/MVFR is expected through the day Fri, with cigs
at eastern sites expected to remain MVFR through the remainder of
the TAF period. Showers/storms and the associated sub-VFR conditions
may redevelop Fri aft at KFAY/KRWI, then at KINT/KGSO late aft/eve.
A front is still expected to slide ssewd through central NC Fri
morning, with winds generally becoming nnely behind it. -KC
Outlook: A gradual return to mainly VFR conditions and dry weather
is expected Friday night into Sunday. Shower and storm chances
increase once again on Monday and especially Tuesday. -Danco
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Friday evening for NCZ027-028-042-043-077-
078-085-086-088-089.
Flood Watch until midnight EDT tonight for NCZ083-084.
&&
$$
SYNOPSIS...Kren
NEAR TERM...Kren
SHORT TERM...Hartfield
LONG TERM...Green
AVIATION...KC/Danco
Area Forecast Discussion
National Weather Service Reno NV
150 PM PDT Thu Jul 25 2024
.SYNOPSIS...
* Thunderstorm chances shift to west central NV through this
evening, with another risk of isolated storms in parts of
western NV Friday.
* Gusty southwest winds and lower humidity bring increased fire
weather concerns to northeast CA and northwest NV this afternoon
and locally to all areas Friday.
* Dry conditions with cooler temperatures near seasonal averages
will prevail this weekend through the remainder of July.
&&
.DISCUSSION...
* CHANGES: Increased slight chance of thunderstorms across western
NV late Friday. Also, increased winds across the ridges a bit.
Otherwise, no major changes with isolated storms across western
NV and breezy conditions through Friday followed by drier and
seasonally warm temperatures for the weekend.
* Isolated storms were developing in tandem with the HREF across
the eastern Sierra of southern Mono County eastward into western
NV. Confidence in timing and location has been above average, so
expect storms to push off the Sierra by this evening with most
activity along or east of Hwy 95 before exiting later in the
evening. Storms are faster moving, so flooding is less of a
concern, although cannot completely rule out a brief downpour or
training cell that could cause some local issues as moisture
remains abundant. Elsewhere, it will be storm-free with gusty
southwest winds to 30-35 mph through sundown, bring local chop
to Lake Tahoe and Pyramid Lake along with critical fire weather
across northeast CA/northwest NV where RH levels have dipped
below 15%.
* We continue to watch a pesky shortwave moving inland Friday with
some timing and location differences but a general consensus for
a threat of elevated/dry lightning across western NV late
Friday, starting near and south of Hwy 50 late afternoon and
spreading northward during the evening hours, possibly into the
first few early hours of Saturday morning. We introduced a
15-20% chance of thunder along Hwy 95 and northwest NV, but a
few scenarios are a bit farther west such that the chance is not
zero along or just east of Hwy 395/I-580 from Reno-Carson City
northward to Susanville. Afternoon winds will continue to be
breezy most areas, but not quite as strong with most gusts 25-30
mph.
* For the weekend and beyond, we are not anticipating any big
weather interests as it will be seasonably warm with typical
late day winds. The only fly in the ointment would be smoke from
nearby wildfires. Latest HRRR simulations indicate best smoke
potential across NE CA and far NW NV emanating primarily from
the large Park Fire in northern CA. Best to expect at hazy skies
but not be surprised if the smoke forecast changes in the days
ahead.
Hohmann
&&
.AVIATION...
* STORMS: Isolated thunderstorms were developing from the Mono
Sierra crest near Tioga Pass down to Mammoth and then eastward
into southern southern Lyon and Mineral counties, so it appears
the latest HREF guidance on timing and location are on track.
Activity should move off the Sierra crest by late this afternoon
with focus on western NV near and east of the Hwy 95 corridor.
So there is a 15% chance of thunder prior to 26/00Z for KMMH
with other airports remaining storm free through tonight. For
Friday, an upper level wave will bring a 10-20% chance of
storms across W NV, focusing east and north of Reno. There is a
10% chance of storms at KRNO-KCXP-KMEV after 27/00Z.
* WINDS: SW-W winds this afternoon with gusts 25-30 kt across most
of the main terminals, and 20-25 kt on Friday.
Hohmann
&&
.FIRE WEATHER...
* A Red Flag Warning remains in effect today for northeast
CA/northwest NV as SW-W wind gusts increase to near 35 mph and
afternoon humidity drops below 15%. Fire zone 271 was added
earlier this morning. Active fires are already present and these
conditions can lead to more rapid fire spread. Holdovers from
Wednesday`s lightning could be a problem in these areas as well
as the Sierra Front where near critical conditions will occur as
early as this evening for 2-3 hours.
* Friday we have included fire weather headlines due to increased
lightning potential and/or gusty outflow winds with low
humidity. A 15-20% chance for isolated dry thunderstorms will be
for northwestern Nevada and the Basin and Range for Friday.
Right now, best coverage appears to be along and and east of Hwy
95 starting southern Lyon-Mineral County late afternoon and
spreading north during the evening. There are still a few
scenarios that bring a 10% chance of lightning as far west as
Reno and east of Hwy 395 in Lassen County.
* Smoke from ongoing fires in California and northern Nevada
expected to spread across northeastern California and northwestern
NV through Friday. The HRRR smoke trajectory model keeps most of
the smoke plume north of the Reno-Sparks urban area, with the
plume reaching areas near Pyramid Lake and extending into Pershing
and Churchill counties. This trajectory assumes similar smoke
output and no disruptions from t-storm outflows.
* Additional fire starts/growth and holdover ignitions from recent
days of significant lightning activity are possible, so more
areas could be affected by haze and smoke.
MJD/HRICH
&&
.REV Watches/Warnings/Advisories...
NV...Red Flag Warning until 9 PM PDT this evening NVZ458.
CA...Red Flag Warning until 9 PM PDT this evening CAZ270-271-278.
&&
$$
Area Forecast Discussion
National Weather Service Blacksburg VA
1025 PM EDT Thu Jul 25 2024
.SYNOPSIS...
A weak front will push through the region tonight and then
position itself in the Carolinas on Friday night. Conditions
slowly improve over the weekend and drier and sunnier skies
return as high pressure builds in from the north. Thunderstorm
chances gradually increase through the beginning of next week as
another front pushes closer to the region.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1025 PM EDT Thursday...
Key Messages:
- Isolated showers and thunderstorms
- No changes in temperature forecast
Have updated probability of precipitation based on the latest
radar trends.
Previous Discussion:
Best instability is in the Virginia piedmont this evening,
mainly north of Route 460. HRRR guidance keeps a cluster of
showers and thunderstorms around Buckingham county until
midnight and isolated showers in the New River Valley.
No change to the expected fog and stratus that will develop
overnight. No change to overnight low temperatures.
Previous Discussion:
Stationary front has washed out and main surface front now
draped across the Ohio Valley this afternoon. This front will
push south through this evening and overnight. Have had some
clearing, but still mostly cloudy across the area, therefore
toned back on storm/rain chances moving into the latter portions
of the afternoon. Precipitation wanes overnight and likely to
see fog develop across the area, lingering through daybreak
Front will push to the VA/NC border by Friday morning, but
clouds still likely as flow becomes reminiscent of a wedge
featuring east/northeast wind. With that said, mostly cloudy
skies seem likely through Friday evening, along with a few
mountains showers over the Blue Ridge and perhaps an isolated
thunderstorms across the North Carolina mountains.
As such, with ample cloud cover, temperatures below normal
through Friday. Highs today and tomorrow several degrees below
normal.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 130 PM EDT Thursday...
Key Messages:
1. Limited precipitation probabilities over the area through the
period.
2. Near normal temperatures expected.
A high pressure ridge aloft over the southeastern US expands into
the Mid Atlantic over the weekend, and while a surface high develops
over the northeast, and wedges down against the eastern side of the
Appalachians. The cold front that will have crossed the area during
the day Friday will be situated across the Carolinas by Friday
night, so some isolated to scattered showers and possible storms may
linger overnight along and south of the VA/NC border.
The airmass behind the front will be drier and cooler, and
temperatures will fall closer to seasonal norms. Northeasterly winds
and lower humidity, as well as residual cloud cover, will make
Saturday feel cooler than recent days. Temperatures warm a few
degrees Sunday, as southwesterly return flow around the high
increases over the area. This moisture return could spark a few
showers over the southern Blue Ridge and Mountain Empire regions,
but coverage looks to be scattered at best, and thunderstorm
probabilities are less than 35% for Sunday afternoon and evening,
mainly over northwest NC.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 130 PM EDT Thursday...
Key Messages:
1. Scattered showers and storms through middle of work week.
2. Temperatures on warming trend through midweek.
A 500mb trough deepens over the eastern US downstream of an upper
ridge building over the southwestern US through the beginning of the
work week. Near daily chances of showers and storms begin Monday
with upper shortwaves tracking through the main upper trough.
Increasing atmospheric moisture and instability will keep chances of
showers and storms over the area through at least the middle of the
week. Greatest probabilities of thunderstorms look to be Tuesday and
Wednesday.
Temperatures will be on a warming trend through the middle of the
week, as southwesterly flow continues to advect warmer and more
moist air into the region. Highs will be in the low 80s in the west,
mid 80s in the east and Roanoke Valley to start the week, warming
several degrees to mid 80s in the west, upper 80s to near 90 in the
Piedmont and Roanoke and Southern Shenandoah Valleys by the end of
the forecast period.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
As of 745 PM EDT Thursday...
Mainly mid and high VFR clouds this evening. Also isolated
showers near KBCB at the beginning of the TAF forecast period.
MVFR to LIFR fog and stratus settle in overnight. Fog
diminishes by 13z/9am, but could still have lingering IFR/MVFR
cigs due to northeast flow trapping residual low level moisture
along the east slopes of the Blue Ridge.
Average confidence for ceiling, visibility, and wind.
Extended Aviation Outlook...
Should see less rainfall/storm chances Friday through Sunday so
mainly VFR outside of late night IF/LIFR fog/stratus.
Deep moisture returns from the southwest Sunday night through
Tuesday with a chance for showers/storms mainly in the
mountains. Mainly VFR outside of any storms.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...BMG
NEAR TERM...AMS/BMG
SHORT TERM...AS
LONG TERM...AS
AVIATION...AMS/BMG