Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/27/22
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
851 PM CDT Tue Jul 26 2022
.UPDATE...
Issued at 849 PM CDT Tue Jul 26 2022
The sfc front has exited the region this evening, thus the main
chances for rain have shift east/south of the CWA. The rest of the
night looks pretty much dry. That said the HRRR does try to bring
in isold showers late, but am not sure it`s worth the mention in
the forecast, so far now will keep it dry. Temperatures look fine.
&&
.SHORT TERM...(This Evening through Wednesday Night)
Issued at 258 PM CDT Tue Jul 26 2022
The forecast challenge is lingering precipitation chances
tonight/Wednesday along with temperatures.
At 2 PM CDT, skies are partly cloudy and winds have switched around
to the northwest behind a cold front that is almost through the CWA.
Winds out ahead of the front are out of the southwest. Temperatures
have been warming through the 70s and 80s this afternoon. The
earlier showers/weak thunderstorms ended a couple hours ago.
However, beginning to see the cold front up in North Dakota and
Minnesota become active here this afternoon. There are even a couple
of showers developing on the boundary over this CWA over/near the
Clark/Day/Codington counties border area.
The general consensus is enough instability/shear exists over this
frontal boundary to support some isolated/widely scattered multi-
cellular convection this afternoon into early this evening mainly
east of a line from Lake City to Tulare. Not really expecting any
severe weather out of this afternoon`s convection. Perhaps some
small hail and localized heavy downpours will be the biggest threats
with most of the convection. Once the boundary clears the eastern
edge of the CWA, precipitation chances take a break.
There is some question as to whether or not a couple of shortwaves
embedded within northwest flow cloud bring some small/localized rain
shower chances to the CWA later tonight and then again on Wednesday.
Overall, the region is being influenced at the surface/in-the-low-
levels by high pressure working down out of Canada tonight through
Wednesday night. Leaning moreso toward a dry forecast for now in the
short term, with room to introduce some small pops as needed.
Temperatures are going to be dropping into the 50s overnight
tonight, and again Wednesday night. Actually, it would not be a
surprise if a few localities across north central South Dakota dip
down into the upper 40s for low temperatures Wednesday night. The
low level neutral air or cold air advection pattern will help keep
the lid on temperatures Wednesday, with highs likely only topping
out in the 70s, with some low 80s possible down over southwest and
south central South Dakota.
.LONG TERM...(Thursday through Tuesday)
Issued at 258 PM CDT Tue Jul 26 2022
Surface high pressure will be parked over the area Thursday and
looks to stick around through the day Friday. This will bring dry
conditions and coolish temperatures in the 70s and low 80s. Low
temperatures Friday morning under the high could still potentially
drop into the upper 40s under the right radiational cooling
conditions. Current forecast lows are in the low 50s to right around
50 for most areas, but NBM10 still showing some upper 40s, so not
totally out of the question given the right conditions. It`s not
until Friday night when the surface high moves away and warm/hot air
begins moving back into the region for the weekend, with highs
rising back into the 80s and 90s. Dewpoints likely getting back into
the 60s as well, mainly east of the Missouri. Not overly oppressive,
but still a noticeable uptick in the muggy conditions nonetheless.
As for precipitation, things look mostly dry throughout the period.
About the only time there looks to be a chance for precip would be
Saturday night into Sunday, as shortwave energy and a surface trough
move through the area. That said, an ensemble approach to POPs would
suggest keeping chances fairly low at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 608 PM CDT Tue Jul 26 2022
Terminals KABR,KATY,KPIR,KMBG
VFR skies/vsbys are expected through tonight regionwide.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TDK
SHORT TERM...Dorn
LONG TERM...TMT
AVIATION...TDK
Area Forecast Discussion
National Weather Service Duluth MN
648 PM CDT Tue Jul 26 2022
.DISCUSSION...(This evening through Monday)
Issued at 311 PM CDT Tue Jul 26 2022
Summary: A cool week ahead with several cold fronts bringing
showers and thunderstorms for the first half of the week. Dry at
the end of the week, but heating up for the weekend.
A cold front is moving through the Northland today. A few of the
cells that it has generated up on the Iron Range have produced
copious amounts of rainfall (in excess of 3”). CAPE has been
underplayed from prior model guidance – the latest RAP analysis
has around 1500 to 2000 J/kg of MUCAPE with higher values near
Brainerd where surface dewpoints are in the mid 60s. PWATs near
1.5” will support healthy rainfall totals with whatever
convection continues with the cold front this evening.
After the cold front passes, it appears fog may be a threat
overnight as saturated soils with clearing skies should generate a
good environment for fog. Winds will be light, but not calm so
that could be a limiting factor with mixing still occurring albeit
weak/light.
A weaker cold front will cross Wednesday for more shower
activity, but most of that should be north of Highway 2.
High pressure builds for the latter half of the week giving quiet weather.
Friday and Saturday should be dry and a little warmer after what
should be a cool week. An upper trough approaches for Sunday
bringing back a chance for showers and storms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 649 PM CDT Tue Jul 26 2022
A cold front is passing through this evening with showers and
thunderstorms associated with it. The rain has passed through
HIB/INL and will pass through DLH/BRD in the next hour or two. HYR
will see shower and storm chances starting in a couple hours. A
wind switch to northwesterly will follow the frontal passage.
Winds will become lighter tonight, and with the clearing skies and
high moisture content at ground level due to today`s rainfall,
there is a chance for some fog to develop. Fog is not a guarantee
at all terminals, and visibilities will likely fluctuate a bit if
fog does form. This is mainly because winds are not likely to
become completely calm, and there may be enough mixing in place to
prevent dense fog except for short durations. The only exception
may be at HYR where the timing of the frontal passage and rain may
be just right for winds to become very light behind the cold front
for a period later tonight, allowing a greater probability of some
dense fog. An approaching upper level trough may allow for some
scattered redevelopment of showers later tonight, mainly at
INL/HIB. VFR conditions are expected for most of tomorrow morning,
but scattered showers and storms are likely to develop during the
afternoon with upper level waves and another cold front passing
through.
&&
.MARINE...
Issued at 311 PM CDT Tue Jul 26 2022
Sub-SCA conditions out on the lake for the next 48 hours, but
gusts will flirt with 20 knots this afternoon as a cold front
crosses bringing non-severe thunderstorms with it. Fog is expected
to develop overnight into Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 56 76 55 70 / 50 30 20 50
INL 51 71 52 65 / 30 80 60 60
BRD 56 76 54 70 / 30 20 10 20
HYR 56 77 52 70 / 70 20 10 40
ASX 58 79 56 73 / 70 20 20 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
DISCUSSION...Wolfe
AVIATION...JDS
MARINE...Wolfe
Area Forecast Discussion
National Weather Service Houston/Galveston TX
644 PM CDT Tue Jul 26 2022
.AVIATION [00Z TAF Issuance]...
While activity along the sea breeze has dissipated, there does ap-
pear to be additional development approaching from the E/NE. But,
the loss of daytime heating should help to keep things quiet into
the evening/overnight hours. Brief patchy low clouds/fog is going
to be possible at some inland terminals around sunrise once again.
Rain chances could be enhanced a bit more tomorrow as a series of
weak shortwaves approach and move across from the east. Kept with
the mention of VCTS for most sites tomorrow afternoon. 41
&&
.PREV DISCUSSION /Issued 334 PM CDT Tue Jul 26 2022/...
SHORT TERM [Tonight Through Wednesday Night]...
Afternoon showers and thunderstorms are a little more active this
afternoon due to increased low level moisture. Temperatures outside
of rain-cooled air remain relatively unchanged with inland areas
reaching the upper 90s to low 100s this afternoon and coastal areas
reaching the mid 90s. Overnight lows will only cool down to the
upper 70s to low 80s.
Tomorrow`s weather pattern will be fairly similar again, except an
easterly moving mid-level shortwave will undercut the ridge
overhead. This combined with continued low level moisture advection
will enhance rain chances tomorrow. Should the shortwave arrive
early (like the 18Z HRRR is suggesting) then, we can expect more
coastal showers in the morning that will push inland throughout the
day, before dissipating by the late afternoon as the environment
gets mixed over. However, other hi-res models are hinting at the
shortwave arriving later and coinciding with peak daytime heating.
If that`s the case, we can expect enhanced sea breeze and bay breeze
convection in the afternoon and dissipating after sunset with the
loss of daytime heating. Long story short, rain chances will range
from 30-40% tomorrow compared to the 20% today.
Regarding tomorrow`s temperatures, 850mb temperatures cool a degree
or two and this combined with some increased cloud cover will help
cool surface temperatures a few degrees. Despite this, we can still
expect inland areas to reach the upper 90s to low 100s while coastal
areas will reach the low to mid 90s. Overnight lows on Wednesday
will cool to the upper 70s to low 80s again.
Lenninger
LONG TERM [Thursday Through Tuesday]...
The persistent mid/upper level ridge will continue to bring
above normal temperatures to the area at the end of the week,
over the weekend and on into the start of next week. Our area
will occasionally reside on the southern fringes of the ridge
which will allow for the possible of weaknesses (inverted
troughs) to move across the area and bring us a chance of
showers and thunderstorms (20%-30% range). At this time, it
looks like Thursday (and maybe Friday?) might end up being
our best chance of seeing these storms through the period.
The big weather issue will still be the heat with highs in
the upper 90s thru lower 100s inland and in the lower to mid
90s near and along the coast. Heat index values look to
continue to peak just below Heat Advisory levels almost every day.
Have included a Climate section below with some updated
information on the July heat.
42
.CLIMATE...
Here is an update on hot July has been. For July 1-25...
-College Station
...Average high is 103.4 degrees (8.3 degrees above normal)
(warmest July on record is 101.1 in 1917)
...Average low is 78.5 (3.7 degrees above normal)
(warmest July on record is 77.5 in 2009)
...Average temp is 91.0 (6.1 degrees above normal)
(warmest July on record is 89.1 in 2009)
-Houston
...Average high is 98.9 degrees (4.6 degrees above normal)
(warmest July on record is 99.4 in 1980)
...Average low is 77.8 (2.2 degrees above normal)
(warmest July on record is 78.3 in 1963)
...Average temp is 88.3 (3.3 degrees above normal)
(warmest July on record is 87.5 in 1980)
-Houston Hobby
...Average high is 97.8 degrees (5.1 degrees above normal)
(warmest July on record is 96.6 in 1998)
...Average low is 78.8 (2.3 degrees above normal)
(warmest July on record is 78.8 in 2020)
...Average temp is 88.3 (3.7 degrees above normal)
(warmest July on record is 86.8 in 2016)
-Galveston
...Average high is 92.8 degrees (1.6 degrees above normal)
(warmest July on record is 94.7 in 1875)
...Average low is 83.8 (4.2 degrees above normal)
(warmest July on record is 82.2 in 1993)
...Average temp is 88.3 (2.9 degrees above normal)
(warmest July on record is 87.4 in 1875)
Galveston`s low temperature this morning was 86 degrees.
If the temperature does not fall below 86 before the end
of the day, this will tie their all-time record high
minimum temperature for July that was set earlier this
month four other times (19th, 20th, 23rd and 24th). Their
all-time record high minimum temperature for the entire
year is 87 degrees, and it was set four consecutive days
in a row (8/31/2020 thru 9/3/2020).
If Galveston`s low temperature today does not fall below
85 degrees, this will be the 8th consecutive day that
their low temperature has been at or above 85 degrees and
will be a brand new record (current record of seven consecutive
days has happened four times, including this month between
the 4th and the 10th and also the current streak between the
19th and the 25th).
-Palacios
...Average high is 93.1 degrees (1.5 degrees above normal)
(warmest July on record is 93.6 in 1954)
...Average low is 83.0 (4.0 degrees above normal)
(warmest July on record is 81.3 in 2009)
...Average temp is 88.1 (2.8 degrees above normal)
(warmest July on record is 87.0 in 2019)
College Station records date back to 1889
Houston records date back to 1889.
Houston Hobby records date back to 1931.
Galveston records date back to 1874.
Palacios records date back to 1943
42
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 78 101 78 102 78 / 10 20 10 10 0
Houston (IAH) 78 98 78 98 79 / 20 40 20 30 0
Galveston (GLS) 85 94 85 93 86 / 30 30 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
Area Forecast Discussion UPDATED
National Weather Service Hanford CA
435 PM PDT Tue Jul 26 2022
...Update to Air Qaulity Issues Section...
.SYNOPSIS...
Triple digit heat in the valley and Sierra foothills with showers
and thunderstorms over the Sierra will continue for the 7-day
period. Smoke from the Oak Fire will reduce air quality throughout
the region.
&&
.DISCUSSION...
Area of subtropical moisture spread across parts of the nrn cwfa
and provided some light showers across Merced county early this
morning. isolated showers and thunderstorms are expected above
7000 feet today and mainly confined to the crest. Radar is
picking up some of the showers attm.
Temperatures have been steady over the past few days as triple
digits continue over the SJV and the Kern county desert regions.
Winds have been light and mainly terrain driven, except gusty and
erratic near heavier showers and thunderstorms. Ensemble guidance
is indicating that we will still remain at or just above triple
digit values through the forecast period. The hottest day appears
to be on Friday where there is a 58 percent chance of getting
over 105 at Fresno.
Subtropical moisture will shift eastward as high pressure builds
over the PACNW through Wednesday and remain nearly stationary
through the weekend. Temperatures will max out on Friday as the
high will be centered over NORCAL. Strong offshore flow will shut
down any convection across the Sierra by the end of the week and
into this weekend. As mentioned earlier, the hottest day appear
to be Friday attm.
Smoke from area fires will play a role in parts of the SJV as a
more easterly component will start to bring more smoke into the
SJV than we have seen so far. HRRR surface smoke model is
spreading smoke into the SJV and mainly along the eastern side and
Sierra foothills over the next few days.
&&
.AVIATION...
MVFR or lower visibilities are likely in Mariposa and Madera
Counties due to heavy smoke and haze from the Oak Fire.
Otherwise, VFR conditions will prevail across the remainder of
Central California for at least the next 24 hours.
&&
.AIR QUALITY ISSUES...
On Wednesday July 27 2022... Unhealthy for Sensitive Groups in
Fresno... Kern... Madera... Merced and Tulare Counties... and
Sequoia National Park and Forest.
&&
.CERTAINTY...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
an/or to provide feedback.
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
public/aviation/fire weather....JDB
pio/idss/social media...........CM
weather.gov/hanford
Area Forecast Discussion
National Weather Service Northern Indiana
744 PM EDT Tue Jul 26 2022
.SYNOPSIS...
Issued at 345 PM EDT Tue Jul 26 2022
Skies will remain mostly cloudy overnight with lows in the lower
to middle 60s. An increase in moisture late tonight and into
Wednesday brings a chance of showers and perhaps a few
thunderstorms Wednesday with highs near 80. A low chance of rain
lingers into Thursday. Less humid air then filters into the
region Friday into the weekend.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 345 PM EDT Tue Jul 26 2022
Broad/shallow North American trough through base of two Canadian
cyclones and elongated anticyclone stretching from northeast Texas
to Bermuda high. As Manitoba low dives southeast into Ontario an
attendant front over the Upper Midwest will slide eastward through
the Upper Great Lakes/CWA early Wednesday afternoon. Meanwhile,
monsoonal moisture tap into the Intermountain Region being routed
by deep westerly confluent flow through Central Plains-Lower Ohio
Valley-Carolinas noted per water vapor imagery. This moisture
conveyor accentuating surface/low level thermal gradient stalled
along Kansas/Oklahoma border into Tennessee. Moist (14-16 g/kg
1000- 850 mb mixing ratios) ascent into cool side of frontal zone
responsible for heavy/regenerative convection from northern
Missouri into Lower Ohio Valley overnight into this afternoon.
Record rainfall rates/amounts have led to ongoing historic flood
event in Saint Louis metro area today.
For tonight, concern is how far north does northern edge of rain
showers lifts late tonight into Wednesday morning. Embedded
shortwaves within deep westerly flow will buckle/back upstream low
level /925-850 mb/ flow and afford moisture transport north of
I-70 early tonight, but then veer back more westerly by daybreak.
Richer moisture will have showers likely reaching into far
southern CWA late with notably sharp northern edge/trailing
chances.
Next concern is how much destabilization can be realized prior to
northern stream frontal passage Wednesday. Convection failure
more probable given paltry mid level lapse rates and thick cloud
cover debris, with pattern recognition pointing to hindered
surface insolation. Increasing low level convergence and moderate
/30-35 knots/ deep layer shear in place does provide a
conditional/low thunderstorm chance midday/afternoon Wednesday
with perhaps some gusty winds should pockets of MLCAPE 1500 to
2000 J/kg per the aggressive HRRR be realized.
&&
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 345 PM EDT Tue Jul 26 2022
Secondary northern stream shortwave trough rotates through
Thursday with relatively low chances for convection. Strong
surface ridge follows as mid level trough ejects through southeast
Canada. Notably less humid airmass with surface dewpoints into
the middle/upper 50s Friday into the first part of the weekend.
Gradual moisture return as high slides to eastern seaboard,
combined with a minor shortwave digging southeast through the
Upper Mississippi Valley, brings chances for showers and a slight
chance of thunderstorms early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 743 PM EDT Tue Jul 26 2022
Continued with similar forecast, though have concerns with
respect to how expansive morning IFR stratus is across far
northern Indiana Wednesday morning, especially at KSBN. Moisture
tansport from the Middle Ohio Valley west into the Ozarks will
shift northward overnight as 925-850 mb flow within belt of
moisture backs southwesterly and increases to 40 knots through far
southeast Illinois/southwest Indiana. Cooling boundary layer and
ascent should allow for saturation/stratus development by
daybreak. Northern extent of IFR ceilings remains the queestion
with the highest low level theta-e air only reaches to about KLAF-
KFWA line by 12 UTC then is shunted eastward.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...Murphy
SHORT TERM...Murphy
LONG TERM...Murphy
AVIATION...Murphy
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Area Forecast Discussion
National Weather Service North Platte NE
638 PM CDT Tue Jul 26 2022
.SHORT TERM...(This evening through Wednesday night)
Issued at 132 PM CDT Tue Jul 26 2022
A large upper level area of low pressure will remain located near
Hudson Bay through Wednesday. Meanwhile upper level ridging has
expanded northward across the Pacific west coast states. Between the
two features moderately strong west-northwest flow aloft is in place
across our region. At the surface a weak cold front is sagging
southward through the area. The front by early this evening should
extend from northeast CO through central into northeast NE. Most CAM
guidance develops scattered convection late this afternoon near the
front, but this is mostly just south and east of our counties of
western and north central Nebraska. There has been a signal the past
several runs of the HRRR that a few storms could develop in the
moist post frontal upslope environment across the western Sandhills.
If these were to form then a small cluster could move southeast
across central into southwest NE early this evening. Clearing is
taking place across the area late this morning, and will allow for
some instability to develop this afternoon. Shear is such that storm
organization could occur with a few briefly severe cores possible.
A small disturbance embedded within the flow aloft may bring another
cluster of showers/thunder to the area late tonight into Wednesday
morning. Moisture will certainly not be lacking, with east to
southeast low-level flow north of the weak cold front continuing to
advect Gulf moisture northwest into the area. PWATS will average
around 1.25" so spotty heavy rain is possible. Unclear has to how
much clearing will occur during the day Wednesday. Several CAMs
linger mid-level showery activity through much of the day. Does
appear that at least some clearing will take place farther to the
west across the Panhandle into northern CO. This is where the
better instability would develop, and most models suggest a
cluster of storms should materialize and track southeast
toward/through southwest NE and northwest KS Thursday night.
.LONG TERM...(Thursday through Tuesday)
Issued at 132 PM CDT Tue Jul 26 2022
The upper low near Hudson Bay will shift eastward by the weekend.
Meanwhile the upper ridge across the western CONUS will begin to
build farther to the east across the Rockies. A weak nearly
stationary front will remain draped across the High Plains from
western KS into the NE Panhandle. Several rounds of showers/thunder
are expected across this area into the weekend. Unfortunately the
main focus for precipitation looks to remain mostly south and
southwest of our area. The exception will be across southwest nearer
the front and stands the better chance of seeing at least some
rainfall. The heat will gradually build back into the area as the
upper level high builds toward the Central Plains next week. Highs
by Monday and Tuesday will be back into the 90s to lower 100s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 638 PM CDT Tue Jul 26 2022
A weak frontal boundary near I-80 this evening will drop south and
be the focus for isolated TSRA across swrn Nebraska until 02z.
Additional scattered TSRA are expected from 06z tonight through
21z Wednesday afternoon. These storms will begin across northwest
Nebraska and spread southeast throughout the night and during the
day Wednesday.
Otherwise, VFR is generally expected throughout wrn and ncntl
Nebraska. The chance of MVFR or lower ceilings is about 20 percent
along and south of Interstate 80.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Taylor
LONG TERM...Taylor
AVIATION...CDC
Area Forecast Discussion
National Weather Service Phoenix AZ
526 PM MST Tue Jul 26 2022
.UPDATE...Updated 00Z Aviation Discussion.
&&
.SYNOPSIS... With plentiful moisture over the Southwest, widely
scattered showers and storms are forecast to continue over the next
several days. Heavy rainfall and briefly gusty winds will accompany
the stronger showers and storms that develop through the work week.
Areas that see repeated rounds of heavy rain will be monitored for
flash flooding. However, the nature of the activity will keep some
areas from seeing significant rainfall, and many hours will be spent
rain- free. Due to thicker clouds and rain in the vicinity, high
temperatures will remain at or below normal, but it will also be
rather muggy.
&&
.DISCUSSION...
Current satellite/radar imagery continues to show scattered showers
and a few t-storms continuing across south-central/SW AZ at this
hour. The most active area this afternoon appears to be over
Pinal/eastern Maricopa/southern Gila County, which missed out on
late last night/early this morning`s rainfall, which saw some areas
of western Maricopa County measure as much as 2 inches of rain. The
MCV that triggered last night`s rainfall has stalled over south-
central AZ. This feature will provide the lift to trigger more
showers/t-storms through this evening. Current ACARS soundings are
showing a very wet atmosphere today, with PWATS all the way into the
2.10-2.20 inch range, which is a near-record levels for this time of
year. The worked-over nature of the atmosphere over western
Maricopa/eastern La Paz/Yuma Counties will likely continue to
inhibit convective active over these regions thru the evening hours,
but areas across eastern Maricopa/Pinal/southern Gila Counties look
like they will have more activity, with the latest SPC showing an
axis of 1000-1500 J/Kg of CAPE extending across those regions. Storm
motion will be quite slow. with mid-level winds remaining quite
light. Combined with high rainfall rates (1-2 inches/hour),
localized flash flooding with be the main issue.
As far as the forecast for tonight thru Thursday is concerned,
latest high-res HRRR and HREF models are suggesting a bit of a break
late this evening, then an increase in convective activity over SW
and the western portion of South-Central AZ as another MCV possibly
rotates southwestward from NW AZ into that region. Again, the main
impacts will likely be locally heavy rain/flooding as well. The
activity appears it will shift to the higher terrain north and east
of Phoenix by Wednesday afternoon as the flow aloft becomes light
easterly, importing a bit drier air into the region ahead of another
weak disturbance that will be moving into SE AZ. Another round of
nocturnal convection appears possible late Wednesday night over the
western lower deserts as the airmass remains very moist (PWAT`s aoa
1.70 inch) with yet another disturbance dropping southern into the
region. Given the continuing threats for convection/very moist
airmass, decided to extend the FLood Watch until 12Z Thursday for
most of our CWA east the the Colorado River. WPC continues to
highlight much of AZ in a slight risk for excessive rainfall
through Wednesday.
Peering out into the extended forecast period, there is not a lot
of change to speak of. The upper ridge axis will continue to
extend from GA - TX - UT, allowing occasional weak disturbances a
path into the Sonoran Desert while no mechanisms will be in place
to scour out our antecedent monsoon moisture. This will keep
20-40% storm chances over Central Arizona and even higher coverage
over the higher terrain at least into the upcoming weekend, and
likely even longer.
This enhancement of the monsoon pattern will continue to give us
a break from the intense heat. Lower deserts will see high
temperatures ranging from 98-105 the next several days, hottest the
farther west you go into SW AZ/SE CA where less clouds/rain are
forecast. Muggy to occasionally humid conditions will also prevail.
&&
.AVIATION...Updated 0026Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Showers and storms this afternoon have developed mostly around the
metro area so far, however at anytime outflows from the
surrounding convection, most favorably from the north to
northwest, could generate new showers and storms. Thus, have
maintained VCSH through this evening. The environment will remain
favorable for isolated to scattered convection through Wednesday
morning. Although confidence in hi-res models is low, majority of
members support most of the overnight convection focusing more
through western Maricopa, perhaps just outside the metro. Primary
threats will be heavy rain, occasional lighting, and brief gusty
winds with magnitudes most likely less than 30 kts. Wind
directions will be driven by vicinity showers and any distant
outflows, but diurnal trends will continue to favor a west through
the day and east overnight. Cloud bases as low as 4-5 kft will be
possible through tonight, but CIGs will mostly be aoa 7-8 kft.
Southeast California/Southwest Arizona including KIPL and KBLH:
Persistent southeast to south winds are expected. At KBLH, there
is a somewhat higher chance of storms late this afternoon through
early Wednesday morning, though probabilities and confidence
remain low. Skies will be a bit clearer at KIPL with showers and
storms not expected into the Valley.
&&
.FIRE WEATHER...
MinRH values will feature a gradient from 20-30% near and west of
the CO River to 35-45% near Phoenix and points eastward. Overnight
recovery will remain good. Heavy rain potential will be best
through tonight and a Flood Watch is in effect for districts east
of the Lower Colorado River Valley (except southern Yuma County).
From mid-week onward, the highest rain and storm chances will
become relegated to the higher elevations with 20-40% chances into
the eastern lower deserts (lower out west). Apart from
thunderstorm outflows, winds will favor familiar warm season
patterns. High temperatures will be below normal through at least
Wednesday over south- central AZ (less so further west) followed
by gradual warming (little change further west).
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flood Watch through late Wednesday night for AZZ533-534-537>563.
Flood Watch through late tonight for AZZ531.
CA...None.
&&
$$
DISCUSSION...Percha/Heil
AVIATION...Benedict/Feldkircher
FIRE WEATHER...Heil/AJ
Area Forecast Discussion
National Weather Service Reno NV
1233 PM PDT Tue Jul 26 2022
.SYNOPSIS...
Near record daytime highs along with warm overnight low
temperatures will lead to high risk of heat health impacts for
much of the region Thursday through Saturday. Smoke and haze from
the Oak Fire will continue to impact parts of the Sierra and
western Nevada. Isolated thunderstorms are expected in the Sierra
today, possibly spreading through out the region by the weekend.
&&
.SHORT TERM...
Widespread haze continues to impact much of the Sierra and western
Nevada with slightly degraded (moderate) air quality. Light
northwest flow aloft and increasing low level mixing should
slowly improve conditions through the day today for most areas
east of the Sierra Crest. For tomorrow, HRRR smoke forecast show
westerly flow returning and potentially pushing smoke and haze
into the Mammoth Lakes area.
Thunderstorm chances continue today, mainly in the Sierra, from
northern Mono County to around South Lake Tahoe. An upper wave
that moved through that area this morning is bringing increased
midlevel moisture and cloud cover along with light virga showers.
Upper level instability is weak and increased cloud cover today
may inhibit surface heating enough to hamper convection a bit.
That being said, the area with the greatest potential for
thunderstorms this afternoon is where some of the higher threat
burn scars remain, including the Tamarack and Caldor, where even
brief heavy rain raises concern for flash flooding and debris
flows. Thunderstorm chances retreat on Wednesday back to
Mono/Mineral Counties.
Otherwise, temperatures remain around the triple digit mark in
the low valleys with generally light winds as our typical
afternoon zephyr winds remain subdued. -Zach
.LONG TERM...Thursday onward...
Greatest concern is the heat risk Thursday through Saturday.
Current forecast is for near if not record highs, with little
relief overnight as low temperatures hover within a few degrees of
record warmth as well. The EFI (Extreme Forecast Index) and SOT
(Shift of Tails) from the EC clearly is picking up on this signal,
with the NBM indicating a 90%+ chance to reach record highs in
several locations. We went ahead and issued a heat advisory for
all zones, except the Sierra, Thursday through Saturday. Don`t get
us wrong, it will be quite warm in the mountains as well, but
there will be more efficient cooling at night, limiting the heat
risk. Try to limit strenuous activity midday and be sure to stay
hydrated. Check in on individuals who are more heat sensitive such
as young children or the elderly, and don`t forget about pets
either.
With the area of high pressure centered almost directly over the
Sierra/western Nevada, winds will be fairly light outside of any
possible thunderstorm development. Speaking of, the subsidence aloft
under the high may help to squelch widespread thunderstorm chances
as it tends to cap things off. However, considering the remnant
elevated PWATs and very warm temperatures, we could still easily pop
isolated thunderstorms for the end of the week into the weekend,
mainly in Mono/Mineral Counties.
A trough moving into the Pacific Northwest Sunday into Monday will
push the high pressure center back over the four corners region.
This will bring a surge of moisture and an increased risk for
thunderstorms Sunday-Monday, with heavy rain a possible concern
as about 1/2-2/3 of ensemble members are pushing PWATs over 0.7",
and some are nearing the 1" mark. Could the prolonged dry streak
at KRNO (currently at 77 days, and tied for 15th longest streak
since 1893) finally end? Sunday and Monday look like our greatest
hope. The one wildcard is there are times we have "too much
moisture" and cloud over too early in the day, limiting stronger
thunderstorm potential. We`ll continue to monitor.
Storm chances decrease in coverage once again by the middle of
next week as drier southwest flow returns to the region. This
would also drop temperatures back closer to normal, which is still
warm given the time of year, but would be a relief after the
triple digit heat. -Dawn
&&
.AVIATION...
A weak wave brought virga and spotty light showers to the region
this morning, which is limiting thunderstorm development to a degree
this afternoon. Per the latest high resolution guidance, isolated
thunderstorms are still expected along the Sierra from KMMH-KTRK
from 21z-03z, with a 40% chance for a storm to impact terminals
directly in this area. Into western Nevada, there is a 20% chance
for terminal sites near and south of US-50 with a 10% chance north
of there.
Smoke from the Oak Fire near Yosemite will continue to be a concern,
but the general lighter flow will keep the worse impacts away
from the eastern Sierra and western Nevada. We`ll mainly see
haze with some slantwise visibility reductions possible. Fire
activity and suppression efforts will determine smoke impacts as
we go through the week.
An incoming heat wave will bring density altitude concerns
Thursday through Saturday. It may also limit thunderstorm chances,
however isolated storms remain possible, with a 10% chance to
impact terminal sites, mainly in Mono/Mineral Counties. Greater
storm chances exist Sunday-Monday across the entire region.
Otherwise, winds will be fairly light surface and aloft outside of
any possible thunderstorm development. -Dawn
&&
.REV Watches/Warnings/Advisories...
NV...Heat Advisory from 11 AM Thursday to 10 PM PDT Saturday
NVZ001-003>005.
CA...Heat Advisory from 11 AM Thursday to 10 PM PDT Saturday
CAZ070-071.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno