Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/04/21
Area Forecast Discussion
National Weather Service La Crosse WI
1046 PM CDT Sat Jul 3 2021
.SHORT TERM...(This evening through Sunday)
Issued at 149 PM CDT Sat Jul 3 2021
Latest water vapor satellite imagery indicates upper level ridge
centered over Minnesota/western Wisconsin and shortwave trough over
the Northern Plains. The upper level ridge has allowed for mostly
sunny but smoky skies and light winds across the area per the
latest visible satellite imagery/metars.
Upper level/surface ridge will allow for dry weather tonight across
the forecast area. Then...shortwave trough over the Northern Plains
will flatten upper level ridge and west to northwest flow aloft
develops across the northern tier states Sunday. This first
shortwave energy weakens as it tracks southeast into eastern
Minnesota and western Wisconsin Sunday. However...there are hints
the shortwave energy has enough lift and moisture convergence to
produce an isolated shower/storm across parts of the forecast area
Sunday afternoon. Though...atmosphere over forecast area is capped
and the chance for any shower/storm are very slim. At this time have
kept forecast area dry for Sunday.
The 03.00z NAEFS show around 1 degree standard anomaly and the
03.12z deterministic models suggest 925mb temperatures warming to
around plus 25 degrees celsius Sunday. High temperatures are
expected to be above normal with temperatures climbing into the
middle 80s to middle 90s in some locations.
.LONG TERM...(Sunday night through Saturday)
Issued at 149 PM CDT Sat Jul 3 2021
A weak shortwave trough and accompanying cold front will drop into
the area from the northwest late Sunday night into Monday. The axis
of greatest instability will initially lie just off to our west
ahead of the front Sunday evening. However, with time the
developing, broadening low level jet will fan moisture transport out
overhead Sunday night, bringing a quick increase in MUCAPE (~2500 to
3000 J/kg per RAP and NAM). But weakening low level frontogenesis
along the front looks to be a limiting factor, with rain chances
generally diminishing as the front progresses southeast overnight.
The good news for Sunday evening fireworks displays is that
shower/storm chances look to generally hold off until after midnight
for majority of the forecast area. Main area of concern for rain
potentially arriving before midnight would be Taylor and Clark
counties, perhaps also from Wabasha to Jackson counties.
The boundary will stall out near I-90 on Monday with a ribbon of
higher PWATs (up to ~1.7") lingering over our southern/eastern
counties despite better moisture transport shifting east. Once
morning clouds depart, expecting plenty of sun with highs pushing
mid 80s to lower 90s. Abundant instability as a result with 2000-
3000 J/kg MLCAPES, but nil deep layer shear and rather weak forcing.
Still, a decent setup for potentially a few stronger storms with
locally heavy rainfall at least for southern half of our area,
contingent on how the morning evolves. Will continue to monitor.
Tuesday looks to bring the greatest chance for any widespread rain
to the area with the front still somewhere over our forecast area
and a shortwave and surface low progged to move overhead from
afternoon-Tuesday night. Potential for PWATs approaching 2" in
spots, so will have to monitor heavy rain potential. High pressure
and a cooler, drier airmass then build in behind this departing
system Wednesday into Thursday, which looks to provide a period of
mainly dry weather. Potentially another system in the Friday-
Saturday timeframe, but predictability and confidence are very low
that far out in the forecast. Increasing return flow does look to
nudge temperatures back to near seasonal normals by late week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1041 PM CDT Sat Jul 3 2021
VFR conditions are forecast for the TAF period with light
southwest winds tonight increasing during the morning, gusting to
20 to 25 kts during the afternoon. Surface winds decrease in the
evening, but LLWS quickly develops at LSE in the evening and
possibly RST later in the night. Isolated showers and storms may
approach from the northwest after 03Z, with the better threat for
scattered storms coming after 06Z. The threat for an isolated
thunderstorm looks to linger through the day on Monday.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...DTJ
LONG TERM...Kurz
AVIATION...Skow
Area Forecast Discussion
National Weather Service Bismarck ND
946 PM CDT Sat Jul 3 2021
.UPDATE...
Issued at 946 PM CDT Sat Jul 3 2021
Thunderstorms have all but ended across western and central North
Dakota. The 00Z CAMS continue to suggest an isolated shower or
thunderstorm remains possible through about 06Z in the central
part of the state, so kept a slight chance pop going to cover that
potential. The more organized convective threat should be to our
east, closer to the H85 jet and low level warm air advection,
which will gradually push farther away (east) tonight.
UPDATE Issued at 711 PM CDT Sat Jul 3 2021
Overall the current forecast is on track with only minor
adjustments made to pops to better reflect the ongoing
convection. Hi-Res models still suggest the best potential for
convection will be in the eastern part of the forecast area, and
this lines up fairly well with the ongoing convection. A few
storms have managed to pulse up, but then weaken in an environment
characterized by MLCAPE of 1500-2500 j/kg and relatively weak
deep layer shear.
UPDATE Issued at 415 PM CDT Sat Jul 3 2021
Ran a quick update to better align pops with current radar trends.
A few thunderstorms have developed across southwest North Dakota
with a few echoes now also showing up across parts of Sioux
County. The latest Hi-Res models continue to have varying
solutions in regards to convective development this evening, but
the HRRR lends support for more storms generally in south central
parts of the state towards the James River Valley. The potential
for a strong to severe storm still looks on track with the latest
mesoanalysis showing an environment of MLCAPE values in the
1500-2500 j/kg range, though shear remains fairly weak at 20 to
30 kts.
&&
.SHORT TERM...(This afternoon through Sunday)
Issued at 244 PM CDT Sat Jul 3 2021
Hot temperatures and thunderstorm potential this afternoon and
evening highlight the short term forecast period.
At the mid to upper levels, a compact shortwave/trough was located
over central North Dakota and continues to move east. A remnant
MCV also continue to rotate towards the Devil`s Lake Basin. This
feature along with any remnant outflow from morning storms will
serve as focus for more thunderstorm development this afternoon
and into this evening.
The best chance for some strong to severe storms will generally
be from the eastern Turtle Mountains and south into the James
River Valley. Here, plenty of buoyancy will be available with
MLCAPE values ranging from 1500 to 2500 J/kg, however shear will
be fairly weak in the 20 to 30 knot range. This will support the
potential for some strong to severe storms capable of producing
large hail up to the size of quarters and wind gusts to 60 mph. A
conditional weak tornado/landspout threat may also exist here
with plenty of background vorticity present along the remnant MCV,
but the lack of better moisture and borderline LCLs may keep this
threat minimal at best.
Further west, a warm front will also move east and may provide
enough lift for more thunderstorm development across portions of
the west and central, but coverage will be limited as weak
transient ridging/height rises try to nudge in. Parameters here
will also be less favorable for severe storms. A cold front then
approaches from the northwest late this afternoon and into the
evening, crossing the state overnight. This afternoon, ahead of
the cold front, breezy southerly winds are likely across the
central and east.
The heat will be the other main story today as a couple of sites
have already hit 100 and numerous sites across western and
central North Dakota are already in the mid to upper 90s.
For your Independence Day, broad ridging and high pressure will
lead to a mostly sunny sky with temperatures not quite as hot as
today with highs generally expected from the upper 80s to upper
90s. Expect breezy winds again across portions of the central and
into the James River Valley, but this time out of the northwest
behind the cold front.
.LONG TERM...(Sunday night through Saturday)
Issued at 244 PM CDT Sat Jul 3 2021
Ridging starts to deamplify again Sunday night as a northern
stream shortwave tries to flatten it. This will lead to increasing
cloud cover and precipitation chances overnight through Tuesday.
Widespread showers are likely with chances of thunderstorms.
However, buoyancy will be fairly limited so severe weather is not
really a concern. While precipitation will be widespread, it will
still be convective/hit or miss in nature but many will see
beneficial rainfall.
A brief cool down continues through Tuesday when highs will range
from the mid 60s across the Turtle Mountains, to the lower 80s
across the far southwest. Ridging builds in again on Wednesday,
warming back into the mid 70s to mid 80s. Thunderstorm chances
return Wednesday night through Friday as a potent shortwave
trough approaches. Details remain uncertain regarding amplitude
and timing as global models continue to flip flop. Over the past
few runs the deterministic ECMWF had started coming in more
amplified/stronger and the GFS had backed off. However, today`s 12z
deterministic GFS is now the stronger solution with the ECMWF
backing off a bit. Taking a closer look at the ensembles, it is
evident that we are still a few days away from getting a clear
picture of how this system will unfold. However, CIPS analogs and
pattern recognition would suggest the potential for at least some
severe weather mid to late week, so we will keep an eye on the
ensemble trends over the coming days.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 946 PM CDT Sat Jul 3 2021
VFR conditions are expected for the 00Z TAF period. Thunderstorms
have all but ended across western and central North Dakota, so
the threat of storms at a terminal locations should be very low.
Winds will gradually diminish tonight before gradually increasing
again on Sunday, especially at KMOT, KBIS and KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...CK
Area Forecast Discussion
National Weather Service Cheyenne WY
548 PM MDT Sat Jul 3 2021
.SHORT TERM...(This evening through Sunday)
Issued at 130 PM MDT Sat Jul 3 2021
Frontal boundary laying along the Wyoming/Nebraska state line this
afternoon. East of the front...dewpoints in the low 60s...while
west...mid 40s are prevailing. The exception being right here at
Cheyenne where an outflow boundary surged north and raised
dewpoints into the mid 50s. Radar showing thunderstorms developing
early today...becoming numerous down here over the south Laramie
Range and Laramie County.
For this afternoon...we need to be on the watch for severe
thunderstorms as storms move into the Panhandle later. SPC
mesoanalysis showing afternoon surface based CAPE up near
200-2500 J/KG. Outflow boundaries will provide additional shear
and low level spin to aid in sustaining thunderstorms. SPC has a
Slight Risk for the Panhandle that is looking better by the hour.
HRRR simulated radar showing initially discreet cells...bowing out
in the Panhandle by 00Z.
Maybe a little less convection for Sunday...but still have
moisture in place for scattered afternoon storms once again. Best
day for storms still looking like Monday when an upper shortwave
moves through the area. Increased PoPs over guidance as
ECMWF...NAM and GFS all showing fairly widespread QPF.
.LONG TERM...(Monday night through Friday)
Issued at 335 AM MDT Sat Jul 3 2021
Long Range models in good agreement through next week, showing a
trend towards hot temperatures by mid to late week as a strong
area of high pressure aloft develops near the four corners region
and lifts northeast towards Wyoming and Idaho. The coolest day
will be Tuesday as showers and thunderstorms will likely persist
through Monday night as a slow moving upper level trough will push
southeast across the high plains. Most models show these showers
continuing into early Tuesday morning with fog development likely
around sunrise. High temperatures on Tuesday may be a few degrees
too high in northwest flow aloft, based on model consensus and
previous ensemble runs. For now, kept highs in the mid 70s to mid
80s. Again these temperatures may be 3 to 6 degrees too high,
especially across the eastern plains. Started lowering POP on
Tuesday afternoon and evening since most of the area should be
west of the trough axis by then. However, still expect widely
scatters showers and thunderstorms near the Colorado border and
locations further southeast towards the trough axis.
Will likely see a beginning of a weather pattern change on
Wednesday as all models show the center of the 595-599dm upper
level high drifting northeast towards Wyoming. Highs in the mid
80s to low 90s will be widespread with even warmer temperatures by
Thursday and Friday of next week. Increasing subsidence and drier
air aloft should suppress deep convection over most of the area.
Can`t rule out a few thunderstorms over the mountains and near the
Laramie Range, so kept POP around 10 to 15 percent for these
areas. Thankfully, the hot weather may be short-lived across the
eastern plains with extended models showing a return to northwest
flow aloft late next weekend and into next weekend. However, areas
further west may still influenced by the strong 600dm upper level
high over southwest Wyoming.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 540 PM MDT Sat Jul 3 2021
KAIA will trend MVFR conditions until 01Z due to thunderstorms. Thunderstorms
will continue across the region until 03Z in the Nebraska
Panhandle. Sites KAIA, KCDR and KSNY will have impacts of gusty
winds up to 35kts and small hail. Afterwards, all TAF sites will
trend VFR with winds under 14kts. Skies will remain cloudy with
mostly SCT clouds sitting at 8-10k ft.
&&
.FIRE WEATHER...
Issued at 130 PM MDT Sat Jul 3 2021
Weak monsoonal moisture will remain over the area through Monday
with daily chances of afternoon and evening showers and
thunderstorms. Best locations for showers and storms will be along
and east of the Laramie Range. Best day for wetting rains Monday
as we see an upper level disturbance move through that will aid in
fairly widespread showers and storms. Warming and drying mid week
on into the end of the week as high pressure builds into the area.
Could see critical fire weather conditions Thursday and Friday as
westerly winds begin to increase and afternoon humidity becomes
critical...especially west of the Laramie Range.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...TJT
AVIATION...AW
FIRE WEATHER...GCC
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
259 PM PDT Sat Jul 3 2021
.SYNOPSIS...Hot and dry weather will persist across the interior
through early next week. Coastal areas will remain seasonably
cooler with night and morning low clouds and fog, and partial
afternoon clearing.
&&
.DISCUSSION...Main concern tonight through Sunday continues to be
the potential for thunderstorms and lightning activity across the
mountains of northeastern Trinity County. A mid level cyclonic
circulation has been advecting mid level moisture above about
15,000 feet northward through the day. Thunderstorm and lightning
activity associated with this disturbance has been initiated by
daytime ground heating. So far there have not been any lightning
strikes away from the terrain, mainly the Sierra Nevada. SREF
plumes continue to indicate sufficient CAPE (100J/kg) for
thunderstorms this evening, generally above 12kft. This
disturbance does not track far enough northward nor does there
appear to be sufficient lifting for this CAPE to be realized.
Moreover, all the convective allowing models indicate storms
occurring well to our east and southeast where the HREF indicates
the highest probabilities of nocturnal storms through early Sunday
morning. There will be some patches of mid clouds that will drift
across Lake and southern Mendocino counties this evening and
overnight. This will need to be closely watched for a very low
chance (less than 5%) for isolated lightning strike with elevated
storms on dry fuels, especially in Lake and NE Mendocino Counties.
Otherwise, hot and dry conditions will persist across the interior
through early next week as a warm and dry airmass remains over
the area. Valleys in Trinity and far NE Humboldt Counties will be
the hottest through Monday with highs around 98-104F degrees.
Elsewhere in the interior, afternoon high temperatures will
generally range from the mid 80s to upper 90s. The heat risk will
remain mostly in the moderate category, but there will be
localized areas of high risk in Trinity County such as around Big
Bar. Interior temperatures should moderate around mid week as a
trough moves toward the Pacific NW coast. Overall, temperatures
will most likely remain above normal all next week. Significant
warming with triple digit interior heat will be possible late in
the week and next weekend as the four corners ridge expands west.
Marine layer depth and stratus cloud thickness has decreased over
the last 24 hours. Low clouds and fog continued to cling to the
shoreline and beaches through the day, however. A shallower
marine layer will generally result in faster clearing for the
coastal river valleys. Persistent areas of stratus and possible
fog will likely occur at the beaches. With cloud bases closer to
the ground, fog may become dense tonight. HREF probability for
dense fog (1/4sm or less) is highest right along or offshore the
Mendocino coast tonight and Sunday morning. NAM12 and GFS BUFKIT
time-height sections indicate very little or minor changes Sunday
through Monday in marine layer conditions. Layer deepening and
thicker stratus clouds will be possible around Tuesday.
&&
.AVIATION...Another day, another bout of coastal stratus. There are
some notable difference versus yesterday`s stratus. Firstly, per
area profiler data, the marine layer has perhaps gotten a bit
shallower at the McKinleyville profiler, while the marine layer
appears to have gotten a bit deeper at the Bodega Bay profiler. In
addition, drier air is advecting S from coastal SW OR across our N
coastal waters. 2 large eddies are evident on visible satellite
imagery. One is downwind from Pt Saint George WSW of Orick and the
other is downwind from Cape Mendocino due W of Ft Bragg.
The best chances of ceilings scattering out at KCEC and KACV will
likely be over the next few hours, but uncertainty is high and any
improvement is likely to be short-lived. Low clouds and fog are
expected to push inland again tonight. However, there is some
indication of some weak offshore flow at both locations later
tonight, and this would act to raise ceilings and improve
visibilities a bit if it pans out.
For KUKI, another night of mostly VFR conditions is expected.
However, low clouds made it just N of the Mendocino county line
early this morning, and the latest HRRR guidance is indicating a
finger of stratus may make it all the way up the Russian River
Valley to the terminal by daybreak. With the slight deepening of the
marine layer and the indication of a substantial offshore eddy W of
Bodega Bay pumping more low-level moisture from S to N, this appears
to be a distinct possibility. Already hinted at this in the 18Z TAF
package, and the oncoming shift may need to ramp up low-level cloud
cover in the 00Z update. /SEC
&&
.MARINE...Advisory-level northerly winds continue across the N outer
waters this afternoon with advisory-level seas and marginal winds
across the S outer waters. We extended the Small Craft Advisory for
the N inner waters earlier, but this will be allowed to expire at 3
PM. Have extended the advisory for the outer waters through midday
Tuesday. Near advisory-level conditions will persist across the
outer waters into the middle of the coming week. Northerlies are
expected to increase a bit by late Wednesday.
Otherwise, a long period SW swell will persist throughout the
period, while a mid-period NW swell moves through the waters
starting Monday. /SEC
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until
12 PM PDT Tuesday or PZZ470-475.
&&
$$
Visit us at https://www.weather.gov/eureka
Follow us on Facebook and Twitter at:
https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka
For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
659 PM CDT Sat Jul 3 2021
.DISCUSSION...(This evening through Saturday)
Issued at 331 PM CDT Sat Jul 3 2021
There are a few chances for thunderstorms over the holiday
weekend, but, despite this, most areas will probably end up
staying dry.
Currently, GOES-16 satellite imagery shows fairly shallow cumulus
development over the western two-thirds of the forecast area.
This should fade with loss of diurnal heating late this afternoon.
The areas to focus on for convective development over the next
couple hours will be over the Nebraska panhandle and eastern
Colorado. These storms may approach western portions of the
forecast area this evening, but the consensus is that they will
largely dissipate before moving in. That being said, there is a
weak upper trough moving through the area, which may be enhanced
by remnant outflow or MCV features, therefore a slight chance of
thunder was added to most of the area late tonight into Sunday
morning.
Isolated showers and thunderstorms are expected to redevelop Sunday
afternoon and early evening, although latest HRRR and NAMnest runs
keep this mostly northwest of the area. Any storms that do mange to
develop will have plenty of CAPE to work with, but shear will be
limited at only around 20kts. Therefore, we cannot rule out a few
strong to marginally severe updrafts, but the overall threat is
fairly low. This activity will be largely diurnally-driven so dry
conditions should return overnight.
The daytime of Monday should also remain dry. With rising heights
aloft, we should see temperatures push into the mid to upper 90s
across the area. Heat index values are expected to remain just short
of advisory criteria (105 degrees), but it will definitely feel hot
due to very light surface winds.
Monday evening and overnight, a few showers and thunderstorms
could move into northern portions of the forecast area as an upper
trough pushes to our north. Better chances for thunderstorms
arrive on Tuesday and Tuesday night as the trough axis and surface
cold front move through the area. This has resulted in fairly
widespread 50-60 PoPs, but total QPF amounts are not overly
impressive. The EPS ensemble only has 0.25-0.50" across the
forecast area through this period.
A few showers or storms may linger into Wednesday, but most of the
area will dry out by the afternoon. The post-frontal airmass will
bump our temperatures down to slightly below normal. Highs are
expected to be in the low to mid 80s. This cooldown will be short-
lived though, as temperatures are expected to rebound to the 90s by
Thursday or Friday. Another cold front is then expected to push
through the area in the Friday to Saturday timeframe, ushering in
noticably cooler and drier air for next weekend.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 654 PM CDT Sat Jul 3 2021
VFR conditions forecast. Although VCTS is mentioned overnight, we
will not likely see this convection make it that far east.
Nonetheless, it is included just in case as there is an mid-level
perturbation that could help sustain convection.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Mangels
AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Lake Charles LA
956 PM CDT Sat Jul 3 2021
.UPDATE...
A stalled frontal boundary continues to bisect the region as
evidenced by the nearly fifteen degree spread in dewpoint from AEX
to LCH. However, in typical diurnal fashion, the vast majority of
precipitation has pushed off into the gulf this evening where it
is expected to remain overnight.
PoP guidance for Independence day has been coming in lower this
evening so opted to lower PoPs through the morning while
maintaining scattered wording through the afternoon. This was the
only significant change to the forecast as other parameters are in
line.
Jones
&&
.PREV DISCUSSION... /issued 644 PM CDT Sat Jul 3 2021/
AVIATION...Widespread rain and storms will decrease through the
evening, however convection will again increase in coverage
tomorrow as heating increases. Spotty reductions in vis and
ceilings can be expected. Light winds will become more northeast
tonight and gradually south through Sunday.
PREV DISCUSSION... /issued 359 PM CDT Sat Jul 3 2021/
DISCUSSION...
SHORT TERM (Today through 12Z Tuesday)...
The surface frontal boundary has been continuing to make its way
south into our area today and is expected to stall over our area
this evening. This has led to elevated shower and thunderstorm
chances throughout the day today with the interaction of moisture
from the Gulf of Mexico. Showers and thunderstorms will be
expected to diminish over land this evening due to weakening
convergence boundaries with the loss of daytime heating as well
as the stalling front reducing any forced uplift over the area.
The latest run of the HRRR (18Z) shows convection forming
primarily along the I-10 corridor and to the south for the
remainder of this afternoon into this evening, with inland storms
dissipating later in the evening.
The stalling frontal boundary will continue to provide elevated
precipitation chances overnight primarily for offshore areas.
However, a few showers could develop near the coast as well during
this time period.
The pressure gradient has remained weak which means winds have been
fairly light and will continue to be over the next few days. The
front will remain stalled over our area and eventually dissipate
by 12Z Tuesday. The lingering frontal boundary will lead to
elevated precipitation chances most notably during the daytime
hours on Sunday and Monday (aided by daytime heating).
Flooding will continue to be a concern over the next few days due
to the elevated chances for showers and thunderstorms combined
with the already saturated ground. Since flow will be light,
storms that develop may be slow movers and cause localized flash
flooding.
55
LONG TERM (Tuesday through Sunday)...
Unfortunately, no real change to the long term period as the
persistent wet pattern looks to continue. On Tuesday, we will be
watching Elsa at it moves into the eastern Gulf. Although no direct
impacts to the CWA are expected, some downstream effects, mainly in
regards to elevated rain chances, are possible. With Elsa to our
east, we will remain under a persistent upper level weakness/trof
over the Southern Plains/Western Gulf. This trof in combination with
a deep influx of moisture through the lower levels will result in
another day of widespread showers and thunderstorms across SE TX/SW
LA, especially during peak heating hours. Coverage should largely
taper off with the loss of heating, however, with the favorable
synoptic set up a better than normal coverage of showers and
thunderstorms is likely overnight as well.
Heading into the midweek, the wet pattern continues as the upper
level weakness remains overhead and PWATs hover around 2 inches. So
with minimal to no capping and plenty of moisture available the
atmosphere will remain primed for widespread convection. Still
expecting the same general pattern of highest POPs in the afternoon,
tapering off overnight, both Wednesday and Thursday. By Friday, the
pattern looks to break a bit as the sub-tropical ridge begins to
build across the Gulf Coast. Ridging should remain overhead through
the weekend, providing some relief from the extremely wet pattern
we`ve been experiencing. That said, still carrying small POPs Fri-
Sun, but coverage should be a lot more isolated. Unfortunately, with
the wet pattern ending it looks like a return of highs in the low to
mid-90s by the end of the period.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 68 94 72 93 / 0 10 10 50
LCH 73 91 74 89 / 60 40 40 80
LFT 72 90 73 88 / 50 30 40 80
BPT 73 90 73 88 / 70 60 50 80
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
935 PM EDT Sat Jul 3 2021
.SYNOPSIS...
An upper trough located overhead today will pass off to our
north and east tomorrow. High pressure will build in early next
week before a cold front approaches the area during the middle
to latter portions of the week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A deep upper level trough by July standards is slowly
progressing off to our east, with a closed low centered over New
England. Mesoanalysis shows an area of low-level convergence and
positive vorticity advection on the back side of this system,
with the axis of focus across central Maryland. With several
hundred J/kg of CAPE remaining in place, showers and a few
embedded thunderstorms continue to develop within this axis.
Locally gusty winds remain possible with this activity, though
overall intensity is slowly decreasing with loss of daytime
heating. While brief heavy rain is also possible, those rates
are rather short in duration and should not lead to flooding.
HRRR has been consistent in allowing any remaining showers to
dissipate between midnight and 2 AM, coincident with the exit of
the vort max.
The dissipating showers will give way to mostly clear skies
overnight. Temperatures overnight will drop back into the upper
50s to mid 60s.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
12z CAMs hint that showers or even a weak thunderstorm may form
late tonight in PA as a disturbance descends down the backside
of the departing trough. The CAMs have this activity moving into
the WV Panhandle around daybreak, before progressing off toward
the south and east toward the DC Metro during the late
morning/early afternoon hours, weakening as it does so.
Additional development of showers and thunderstorms is somewhat
uncertain tomorrow afternoon as heights aloft rise as the trough
pulls away to our north and east. As temperatures warm aloft,
we`ll be left with little to no instability to the east of the
Blue Ridge, even after daytime heating. To the west of the Blue
Ridge, the rising heights will be offset more by advection of
warm/humid air spilling in from the Ohio Valley. The NAM is a
bit of an outlier at the moment, but shows around 1000 J/kg of
MLCAPE developing to the west of the Blue Ridge. It`s
questionable as to whether a storm will even form within the
zone of height rises, but if one were able to, and that
instability was realized, a supercell can`t be ruled out to the
west of the Blue Ridge given the 40 knots of the northwesterly
shear in place. To the east of the Blue Ridge any showers or
storms should be rather weak, with the virtually non-existent
instability. Any activity that develops tomorrow afternoon
should rapidly weaken and dissipate in the evening with loss of
daytime heating. Temperatures will run a bit warmer tomorrow
with highs in the 80s as dewpoints creep up into the lower to
middle 60s.
Weak ridging aloft will build into the area on Monday as much
warmer and humid air advects into the area from the west. With
ridging in place, most of the area is expected to remain dry,
but terrain circulations may produce a few airmass thunderstorms
over the mountains in response to daytime heating. High
temperatures will reach into the upper 80s to near 90, with
dewpoints climbing into the upper 60s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Long term starts out with a ridge over the mid-Mississippi Valley
extending east into the Atlantic. This ridge will gradually shift
eastward as a trough digs over the northern Plains Wednesday and
Thursday before pushing east across the northeast Thursday night.
Another ridge will briefly build behind that trough while another
stronger trough digs in the plains Friday into Saturday. At the
surface, we will stay in a weak ridge of surface high pressure
Tuesday and Wednesday with hot temperatures and likely some
mainly terrain forced convection. Thursday into Thursday night, a
cold front and possibly some remnants of Elsa will cross the region,
bringing better chance of clouds and storms. Partial drying behind
it Friday and Saturday, but the front stalling out could cause
the risk of showers and storms to linger.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Showers and perhaps an embedded thunderstorm will continue to
stream down a convergence axis between DCA and BWI this evening,
but should dissipate between midnight and 2 AM. Brief visibility
reductions and gusty winds up to 30 mph will be the main
threats. Otherwise, VFR conditions are expected through the
night with light and variable winds. Sunday, showers or a storm
appear possible at any terminal, but the overall coverage is
expected to be lower compared to today. Showers Sunday could
potentially start earlier, especially near MRB. Guidance is
beginning to hint that there could be low clouds or fog in
places Sunday night, but there`s still a fair amount of spread.
VFR conditions are expected again on Monday with any storms
staying to the west of the terminals over the mountains.
Mainly VFR Tuesday/Wednesday outside of any patchy morning fog
or afternoon thunderstorms, which should be fairly limited in
coverage.
&&
.MARINE...
While the threat of more numerous strong, gusty storms is
diminishing this evening, showers and perhaps an isolated
stronger storm will remain possible through 2 AM. Various
outflow boundaries are also pushing across the waters, which
will make for erratic and gusty winds even away from
precipitation cores. Later tonight, this activity should
dissipate, leaving sub-SCA conditions through Monday with
somewhat variable wind directions.
Winds mostly sub-SCA, but southerly channeling could bring marginal
SCA gusts at times. Slight risk of a thunderstorm, especially
Wednesday afternoon, which could bring gusty winds.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.
&&
$$
SYNOPSIS...KJP
NEAR TERM...ADS/KJP
SHORT TERM...KJP
LONG TERM...RCM
AVIATION...ADS/RCM/KJP
MARINE...ADS/RCM/KJP
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 305 PM CDT Sat Jul 3 2021
Temperatures and precipitation chances should provide the primary
forecast challenges the next few days. Will run a heat advisory
for Knox and Cedar counties from 1 pm to 8 pm Sunday.
The following features were noted in the large scale pattern at
12Z this morning. Winds at 300 mb were pretty light (generally
under 50 knots) across the central and western US, with stronger
winds from Hudson Bay south into the Tennessee Valley. At 500 mb,
a ridge was in place from Mexico up into the Four Corners region,
with an extension of that ridge across NE and MN. 12 hour height
falls of 50 meters or more extended from Saskatchewan down into
ND. Warmest air at 700 mb was back across the Rocky Mountain
region, with highest moisture content at that level over Mexico,
Texas and the southern parts of NM and AZ. At 850 mb, there was a
trough over the High Plains and a weak ridge from OK up into MN.
A poleward transport of moisture was noted in the 850 mb plot
(and to a certain extent reaching up to near 700 mb) from the TX
panhandle into western KS and central NE. That was also shown in
recent satellite loops this afternoon. 3 PM CST temperatures were
in the mid 80s to around 90 across eastern NE and southwest IA.
Earlier I added some low POPs to parts of northeast NE for later
tonight, based on signals from the GFS and a few of the CAMs
(mainly RAP and 4 km NAM Nest). The evening will probably be dry,
with any storms confined farther to the west. But that deeper
moisture mentioned earlier will be working into our area.
Isentropic forecast plots around 315K show some weak lift and
specific humidity values of 4-8 g/kg. If isolated showers or
storms can develop later tonight, they could linger into mid
morning before dissipating. Otherwise look for clear to partly
cloudy skies tonight, and lows mostly from 64 to 69. Patchy fog
has occurred the past few nights and could occur late tonight,
especially with possible enhancement from fireworks smoke.
For Sunday, the period from mid morning to mid afternoon should be
mainly dry. But as mentioned in the HWO, storms could work into or
develop across parts of northeast NE in the mid to late afternoon
and continue into the evening. Shear and instability suggest a few
storms could approach severe limits. Highs will be mostly in the 88
to 94 degree range, with warmer readings near the SD border. Weak
mid level isentropic upglide will slowly shift southward across the
area Sunday night, so have those low POPs moving into southeast NE
and southwest IA after dark. Lows will be a bit warmer, mostly upper
60s and lower 70s.
By Monday, the mid level pattern will have changed a bit. There will
still be a ridge across Mexico and the southwest US, but northwest
flow will be in place across the northern Plains. Our area will be
on the southern edge of that stronger flow. But as the week goes
on, the flow at the 500 mb level will increase, and be mostly from
the northwest. Any disturbances will be hard to time exactly, but
we will have some decent rain chances, especially Tuesday and
Tuesday night as mid level moisture, a couple of ripples and a low
level front interact over the Central Plains. Hopefully we can get
widespread beneficial rain amounts.
Look for highs Monday in the lower and mid 90s. Tuesday should be
cooler in our northern counties (85 to 90) with upper 80s to mid
90s south. Wednesday will be cooler yet, with highs from the
upper 70s to mid 80s. Highs should reach the 80s Thursday and then
upper 80s to mid 90s by Friday.
Toward the weekend, the mid level flow turns more to the north as
a trough develops from the Great Lakes region down toward TX and
the ridge to the west retrogrades a bit toward the southern parts
of CA and NV. This may drop highs back down into the 80s Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 611 PM CDT Sat Jul 3 2021
VFR conditions will prevail through the period.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory from 1 PM to 8 PM CDT Sunday for NEZ011-012.
IA...None.
&&
$$
DISCUSSION...Miller
AVIATION...DEE
Area Forecast Discussion...UPDATED
National Weather Service Pendleton OR
854 PM PDT Sat Jul 3 2021
.UPDATE...Limited sensible weather concerns with concerns
revolving around fire weather (dry and windy) and moderate winds in
the Gorge. Latest satellite imagery shows some weakening convection
across east central OR south and east of the southern Blues and
Strawberry mountains with mainly inter/intra cloud lightning
associated with it. Otherwise, clearing skies, except lingering high
clouds across parts of northeast OR. The going forecast was largely
on track with updates mainly revolving around capturing near-term
trends and updating for the latest guidance. Strongest winds
tomorrow in the Columbia Gorge spilling into north central OR and
the Kittitas Valley with gusts as high as 30-35 mph with a decent
signal present in both the HREF and NBM. Thus confidence high in
these winds. Otherwise, elevated fire weather conditions owing to
the overlap of breezy conditions and low afternoon humidity tomorrow
across parts of the east slope of the OR Cascades and far western
parts of the Basin.
&&
.AVIATION...00Z TAFs...VFR conditions expected over the next 24
hours. A few upper level clouds are noted across Central Oregon,
as well as a chance for a few passing thunderstorms this evening
across the Strawberry Mountains. BDN and RDM should be west of
this activity. Haze remains possible as well from fires. Breezy
winds 12-20kts this evening continue for DLS/RDM/BDN/PDT, though
all sites except for DLS should see the usual diurnal weakening of
these breezes overnight.
&&
.PREV DISCUSSION... /issued 157 PM PDT Sat Jul 3 2021/
SHORT TERM...Tonight through Monday night. Sunny skies across
most of the region this afternoon with temperatures in the 90s. A
weak system is moving across southeastern Oregon. Satellite
showing cumulus development and could have isolated showers of a
thunderstorm over central Oregon toward the John Day highlands
through the evening. This cloudiness will dissipate late evening
with mainly clear skies overnight. A weak upper level trough
pattern over the Pacific northwest with water vapor imagery
indicating a short wave moving through southern BC and the Pacific
northwest late tonight into Sunday. This system is dry and only
impacts will be westerly winds 10-25 mph. Heights increase some as
upper ridge builds on Monday. The flow aloft becoming more
southwesterly with an upper low off the California coast. Expect
another sunny and hot day with highs in the 90s. Hazy conditions
with smoke aloft will continue this evening and overnight.
Stronger winds aloft Sunday should help improve conditions with
HRRR showing smoke pushing off to the east. A return to southwest
flow Mon will likely bring northern California wildfire smoke
back into the region. 94
LONG TERM...Tuesday through Saturday...Ensembles and
deterministic guidance in good agreement that hot and dry
conditions will continue into next weekend.
Guidance in good agreement that transient ridging will move across
the forecast area Tuesday, followed by a shortwave trough that
will lift northeast into northern WA and southern BC late Tuesday
through Wednesday. ECMWF and GEFS member spreads instill high
confidence in a 3-5 degree warm up Tuesday afternoon into the
upper 90s to 105 with majority of individual members within 5
degrees of each other. By Wednesday, shortwave trough moving north
of the forecast area will help to knock temperatures down a couple
of degrees, though some member spread for Wednesday is greater
with a majority within 10 degrees of each other for some of our
OR and WA cities. The shortwave trough passing across WA will also
restrengthen the marine layer west of the Cascades, which will
induce breezy winds through the Cascade gaps and Gorge Wednesday.
Beyond Wednesday, the general consensus amongst deterministic and
ensemble guidance is for another amplified ridge to develop along
the ID panhandle, while the marine layer slowly weakens. The
return of an amplified ridge would see another warm-up into the
weekend, however, temperatures at this time are only forecast to
reach into the upper 90s to 105 Friday and Saturday afternoon.
Otherwise, the weakening marine layer west of the Cascades will
still induce breezy to locally breezy winds through the Cascade
gaps and the Gorge each afternoon. Lawhorn/82
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 60 95 58 96 / 0 0 0 0
ALW 63 96 64 98 / 0 0 0 0
PSC 62 99 62 100 / 0 0 0 0
YKM 61 96 61 97 / 0 0 0 0
HRI 62 99 62 100 / 0 0 0 0
ELN 60 91 59 94 / 0 0 0 0
RDM 49 92 49 94 / 10 0 0 0
LGD 54 91 53 93 / 10 0 0 0
GCD 55 93 56 95 / 10 0 0 0
DLS 60 92 60 95 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory until 8 PM PDT Sunday for ORZ041-044-049-505-507-
508-510-511.
WA...Heat Advisory until 8 PM PDT Sunday for WAZ024-026>029.
&&
$$
SHORT TERM...94
LONG TERM....82
AVIATION...87
UPDATE...80
Area Forecast Discussion
National Weather Service Phoenix AZ
415 PM MST Sat Jul 3 2021
.UPDATE...
Updated Aviation
&&
.SYNOPSIS...
Chances for showers and thunderstorms will continue through this
weekend with decreasing chances by Monday followed by little chance
for the middle of next week. Storms will be common over the higher
terrain and more isolated on the lower elevations. Gusty winds with
localized blowing dust and localized heavy rainfall capable of
producing flash flooding will be the main impacts. Although a
general drying and warming trend with above normal temperatures is
expected next week across most of the region, isolated storm chances
are likely to persist over the eastern Arizona high terrain.
&&
.DISCUSSION...
Latest signals from observational and model data point to an active
evening across south-central Arizona. The atmosphere is
exceptionally moist today with PWATs ranging from 1.5 to 2.0 inches,
placing it in the 95th percentile of climatology for the day. Latest
RAP streamline analysis depicts the inverted trough across
southeastern Arizona, situated between two anticyclones, one across
western Texas and another across northern Arizona. The resulting
mean layer flow is out of the southeast, which will be favorable to
maintain the deeper moisture. Surface dewpoints have only dropped a
few degrees this afternoon and remain in the lower 60s.
Convection has already initiated along the Mogollon Rim, and across
portions of southeastern Arizona near a well-defined vort max.
Morning KPHX sounding indicated relatively strong easterly flow of
30 kt at 600 mb, which will help to steer activity into south-
central Arizona this evening. Consensus from the CAMs including the
HRRR suggests an outflow boundary from storms in the higher terrain
will also provide the lift necessary to overcome any low-level CIN
in the Valley, while also allowing new cells to propagate rapidly
into the deserts south and west of Phoenix. Consequently, PoPs were
increased to around 50 percent in the Phoenix area, and as high as
70 percent near Casa Grande.
HREF ensemble max gusts are around 50 mph in the strongest storms,
and this is not entirely surprising given the anomalously rich low-
level moisture and subsequent dearth of DCAPE. Nevertheless, strong
wind gusts will still be possible in the vicinity of the outflow
boundary as it descends into the lower deserts. However, the greater
threat will likely be the potential for flash flooding, particularly
across the higher terrain of Gila County and within the recent burn
scars. Latest guidance suggests rain rates could reach 1-3 in/hr in
the strongest cells.
&&
.PREVIOUS DISCUSSION...
A shift in the pattern is expected to begin on Sunday with the drier
southerly flow across the western deserts to begin expanding
eastward late in the day as well as drier northwesterly mid level
flow beginning in the afternoon. Abundant boundary layer moisture
will still be present over much of the region on Sunday, but the
drying aloft will begin to have a noticeable effect on storm
activity, especially across the lower deserts. Showers and storms
will again be likely across the eastern Arizona high terrain Sunday
afternoon, but they will likely have a more difficult time
maintaining their westward push into the south-central Arizona
deserts. Can`t rule out some isolated to scattered storms affecting
the Phoenix area Sunday, but chances mostly drop into a 15-20% range.
The westerly drying will continue early next week, likely ending
storm chances completely across the lower deserts as early as
Monday. Afternoon surface dew points are forecast to drop into the
40s across the western deserts on Monday and then across the south-
central Arizona deserts on Tuesday. The upper level ridge center is
also seen shifting into Nevada while also strengthening, likely
leading to H5 heights increasing to 592-595dm across the Desert
Southwest. The drying boundary layer and increased heights aloft
should push daytime highs to around 110 degrees in the Phoenix area
to 110-113 degrees across the western deserts. So far NBM guidance
has been keeping temperatures just below excessive heat levels for
next week, but if the upper end of guidance proves true then some
heat products may be needed. After a few days of likely minimal
monsoon storm activity confined to the eastern Arizona high terrain,
there are signs of some moisture return and expansion into the lower
deserts at some point later next week. However, the flow pattern
through next weekend does not look very conducive for deep moisture
advection, likely limiting storm chances across the lower deserts.
&&
.AVIATION...Updated at 2315Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
HREF output shows gusty N/NE winds moving through the metro between
01Z-04Z with greater than a 70% chance of gusts above 30kt. There is
also multiple outflows moving in from the south which could create
collisions and erratic directions. NBM probabilities of storms at
any location is better than 50% with HREF neighborhood probabilities
about the same. Kept VCTS along outflow, then VCSH and variable
winds later this evening. Some dust could be picked up along
outflows as well. Cigs 8K-12K ft AGL are forecast by NBM this
evening and overnight. NBM has nearly 30% chance of rain through
Sunday morning, but cut off mention shortly after midnight. NBM
shows west winds and storm chances less than 15% Sunday afternoon
and evening.
Southeast California/Southwest Arizona including KIPL and KBLH:
Southeast to southwest winds are forecast during the periods with
speeds mostly below 12kt. HREF output shows a weakening outflow
boundary hitting KBLH later tonight though probabilities of greater
than 30kt is 10% or less. Cloud heights will be 12K ft and above
with NBM showing less coverage tomorrow.
&&
.FIRE WEATHER...
Tuesday through Saturday:
Moisture will decrease gradually through the midweek period, which
will generally confine the threat of storms to eastern Arizona. A
return of deeper moisture looks possible late next week with storm
chances potentially increasing and expanding westward across
Arizona. Temperatures for the bulk of the period will run a few to
several degrees above normal. Min RH values will drop into the 10-
15% range over southeast California and southwest Arizona and 15-25%
range over south central Arizona with the highest values over the
higher terrain north and east of Phoenix. Max RHs will recover into
the 30-45% range for most locations. Apart from thunderstorms, wind
patterns will follow diurnal patterns.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Kuhlman
AVIATION...18
FIRE WEATHER...Hirsch/Hopper/Kuhlman
Area Forecast Discussion
National Weather Service Pueblo CO
736 PM MDT Sat Jul 3 2021
.UPDATE...
Issued at 735 PM MDT Sat Jul 3 2021
Updated severe thunderstorm watch, dropping El Paso and Pueblo
Counties. Strong to severe storms will still be possible over the
far east plains through this evening.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 358 PM MDT Sat Jul 3 2021
Main Forecast Concerns/Challenges:
1) Increased threat for strong to severe storms through mid to late
evening across the plains, mainly from Colorado Springs to Pueblo
and areas east.
2) Returning thunderstorm chances on Sunday, some of which could
become strong to severe.
Latest trends with thunderstorm development along with thermodynamic
and wind fields indicate an increased threat for strong to severe
storms this afternoon into mid to late evening. The previous thoughts
that the instability would lower across the I-25 corridor from
around Pueblo to Colorado Springs has changed, with latest RAP
analysis indicating 500-1000 j/kg of MLCAPE remaining in place along
with 25-35 kt of shear. This combined with steep mid/low lapse
rates, dewpoints around 60 degrees, and persistent/focused low to
mid level convergence will all support thunderstorm development
across Pueblo and El Paso county this afternoon into early to mid
evening. The current development in eastern Fremont county will
continue to shift more east here in the near term, though may still
become strong to severe before exiting the county. Large hail and
damaging winds will be the main threats with any severe storm in
this location this afternoon. Some isolated storms may occur further
to the south, over the far southern I-25 corridor, but anticipate
these storms to remain sub severe.
Expect all of this development to diminish by early to mid evening,
with focus shifting to likely upstream thunderstorm development
across north central CO. These storms, riding along a southward
moving mid level trough and within surface trough axis, will dive
southeast into eastern Crowley and Kiowa counties this evening,
around 6-8 pm. High dewpoint air in the 60s, MLCAPE values in the
1000-1500 j/kg range, and bulk shear in the 30-40 kt range will
support a continued threat for severe storms during this time. Still
think that half dollar size hail and winds over 60 mph will be the
main risks. This development will shift southeast with time, moving
through other areas along and east of a La Junta to Kim line.
Guidance varies with the intensity of the storms by late evening,
likely given the later time of the day. However, think there will
remain a chance for these storms to remain severe as they push
through all of far southeast CO very late this evening.
Another day of thunderstorm development is expected across southern
CO on Sunday, also with the threat of strong to severe storms. Can`t
rule out a strong to severe storm anywhere across the plains Sunday
afternoon, though a higher risk for severe storms is expected across
the far eastern plains where stronger focus, higher dewpoint air,
and much higher instability will reside.
.LONG TERM...(Sunday night through Saturday)
Issued at 358 PM MDT Sat Jul 3 2021
Main Forecast Concerns/Challenges:
1) Severe storms possible over the southeast corner Sunday night
2) Burn scar monitoring needed Monday and Tuesday
Sunday night...Models are indicating that through the first half of
the night, activity will likely persist along the I-25 corridor and
the eastern plains, with a chance for stronger to severe storms over
the southeast corner. SPC painted the area with a Slight chance for
severe storms, and given the good 0-6km bulk shear and heavy CAPE
forecast for that area, this looks reasonable. Storm threats will be
hail over an inch in diameter and strong wind gusts in excess of 60
mph, along with the possibility of an isolated tornado. Activity
will taper off after midnight, with overnight lows in the 50s for
the high valleys and 60s for the plains. The warmest temps will be
along the CO/KS border where dewpoints are forecast to be the
highest.
Monday and Tuesday...Models are showing run-to-run consistency on
showing Mon and Tue as potential heavy rain days for the mts and I-
25 corridor. The upper ridge of high pressure over the Four Corners
will edge to the northwest, allowing an upper disturbance to cross
the northern Rockies on Monday. This upper level support, combined
with abundant moisture and easterly winds through the column, will
help initiate more convection over the mts and adjacent plains
Monday aftn and eve. As this disturbance continue east-southeast
overnight, a cold front will push into eastern Colorado early
Tuesday, setting up for a slightly cooler day but with another
enhanced round of convection firing off of the higher terrain by
midday. Area burn scars will need to be monitored both days. As for
temps, the high valleys will warm into the 80s both days. Across the
plains, expect the mid 80s to mid 90s on Mon, then 80s on Tue.
Wednesday...This looks like the driest day of the extended forecast,
as the upper high positions right over the Four Corners. Expect
isolated convection over the higher terrain through the aftn and
early eve, with high temps in the 80s for most locations.
Thursday through Saturday...Latest long range models are now showing
the upper high wavering and trying to slide back to the west.
Another shortwave crosses the northern Rockies Thu, then the Dakotas
on Fri, which would help provide the needed lift for enhanced
convection into the weekend, if the upper ridge does move to the
west. For now, the extended procedure indicates that very hot temps
will return to the eastern plains Thu and Fri, with isolated to low
end scattered convection each day over the higher terrain. On Sat,
temps cool by about 10 degrees across the plains along with greater
convection chances as the upper ridge pushes towards the West Coast.
How this ends up remains to be seen, but models do indicate that a
continued busy pattern may be setting up for the region. Moore
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 641 PM MDT Sat Jul 3 2021
KCOS: VFR conditions are expected over the next 24 hours.
Thunderstorms may impact the terminal over the next few hours, but
are expected to stay to the north/east and weaken. Should a
thunderstorms impact the KCOS site, the primary threats would be
gusty winds and small hail, with frequent lightning. Otherwise
expect winds to become light overnight before increasing in
magnitude tomorrow afternoon. Thunderstorms will again pose a risk
to KCOS during tomorrow afternoon, with the primary threats being
gusty winds and lightning.
KPUB and KALS: VFR conditions are expected over the next 24 hours.
Winds will become light and variable overnight, before increasing in
magnitude tomorrow afternoon. Thunderstorms will pose a risk at both
TAF sites, but especially KPUB during the afternoon tomorrow.
Primary threats at this time look to be gusty outflow winds and
lightning.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARBEROGLIO
SHORT TERM...RODRIGUEZ
LONG TERM...MOORE
AVIATION...SIMCOE
Area Forecast Discussion
National Weather Service Sacramento CA
217 PM PDT Sat Jul 3 2021
.SYNOPSIS...
Isolated mountain thunderstorms mainly along and east of the Sierra
Crest this afternoon and evening. Some storms may linger overnight.
Elsewhere, quiet and warm weather continues.
&&
.DISCUSSION...
Early this afternoon, visible satellite shows a line of mid to
high level clouds moving northward across the Central Valley and
some building cumulus over the Sierra Nevada. The Salt fire is
also noted in northern Shasta County with onshore winds pushing
smoke mainly to the north.
Moisture advection associated with the high over the Desert
Southwest will lead to another day of scattered to isolated
thunderstorm chances over the Sierra Nevada. The best chances this
afternoon and evening will be over or east of the crest with the
threats with storms being lightning, gusty winds, and brief
downpours. The Valley will see some additional cloud cover as well
this evening into tomorrow morning. Convection may linger through
tomorrow morning as a weak shortwave rotates around the high
pressure. Both the 3-km NAM and HRRR indicate isolated showers and
storms continuing after midnight, possibly reaching into the
foothills of the Sierra Nevada and southern Cascades. The Desert
high pressure moves eastward a bit tomorrow limiting thunderstorm
chances to over and east of the Sierra crest over Alpine and
Tuolumne Counties. From here, high pressure extends back into the
area early next week bringing the return of dry weather with near to
slightly above normal temperatures.
&&
.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
The Desert SW high will continue to be the main focus during the
extended period. A trough tracking through the PacNW will flatten
out the ridge some and push it back to the east a bit on
Wednesday. This will bring similar highs to Tuesday. As we head
into the later part of the week the ridge will begin to build back
into NorCal and we will see warming temperatures. By next weekend
the ridge will be far enough to the west that it will cut down
onshore flow and flow through the Delta resulting in widespread
triple digits across the lower elevations. Mid level moisture will
be low and no rain or thunderstorm chances are expected for the
extended period.
-CJM
&&
.AVIATION...
VFR with mid level moisture from the Desert SW lifting Nwd over
Norcal through Sun morning with occasional CIGS 150-250 at TAF
sites. Conditions becoming mainly SKC after 15z Sun. Wildfire
smoke from Salt WF in Shasta Co may drift over the KRDD airfield
as drainage winds redevelop overnite causing MVFR conditions in
FU/HZ. Over Siernev, SCT-BKN afternoon cumulus with bases 050-070
and isolated to clusters of thunderstorms developing mostly near
the Crest. Storms may continue/develop overnite due to elevated
instability as upper air disturbance moves from the KMTR area NEwd
into Plumas Co overnite. Influx of mid level moisture with dry
sub-cloud layer could result in locally gusty thunderstorm
downdraft winds G30-40 kts. Small cores of brief downpours also
possible reducing VSBYS to MVFR at times. Less areal coverage of
storms W of the Crest expected on Sun. SWly G35 kts through
Carquinez Strait and into the Delta at times with CIGS AOB 015
spreading inland aft 03z and retreating to the coast by 21z
through the weekend. Density altitude 3000-4000 ft over Nrn Sac
Vly TAF sites during late afternoon/early evening hours through
the weekend.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Las Vegas NV
843 PM PDT Sat Jul 3 2021
.SYNOPSIS...A mix of clouds and sun along with a few isolated
showers will be possible across the Mojave Desert and southern
Great Basin through Sunday evening. Isolated storms with heavier
downpours and gusty winds are possible in Mohave county. Drier
conditions resume early next week with temperatures warming up.
&&
.UPDATE...Thunderstorm outflow from storms over Yavapai County in
Arizona this afternoon pushed into southern and central Mohave
County early this evening producing localized winds to near 50
mph. The outflow lost momentum as it moved west across the county
with gusts reaching only 15-20 mph in Lake Havasu City through
830 pm. For the rest of the night, the latest NBM along with the
HRRR have light shower activity developing across parts of Clark,
Nye, and Lincoln counties. The shower activity may produce gusty
winds and a few claps of thunder but very little rain is expected.
Otherwise, expect mainly clear conditions across the western
portions of the forecast area overnight with partly to mostly
cloudy skies in the central and eastern portions of the area. The
updated forecast for the overnight period is out.
&&
.PREVIOUSLY ISSUED DISCUSSION...
.SHORT TERM...through Sunday night.
A couple areas of focus through this evening. The first is across
the Mojave Desert region (mainly west of Las Vegas) where some
mid- level moisture and a weak impulse entrained in the flow are
resulting in some light shower activity. Instability across the
region remains very low, but enough mid-level instability has been
present for a handful of very isolated lightning strikes, mainly
near Amboy and the Halloran Summit area. This activity will
continue to develop northward this evening, becoming focused
across central Nye county with isolated showers stretching as far
south as the Mojave Preserve. Any precipitation amounts will be
very light (not much more than sprinkles for most areas) though a
hundredth or two is possible in the higher terrain.
Second focus area is further east across Mohave County. Thus far
today conditions have remained dry and stable, but convection is
on the increase across the Mogollon Rim and the mountains of
Yavapai county currently. With a mid-level easterly flow of 15-20
knots, storms organizing in Yavapai county will enter southern
Mohave county later this afternoon. Best chances are mainly from
Kingman southward, as instability drops off quickly with north and
westward extent. Storms entering Mohave county this evening will
likely decay quickly much beyond the US-93 corridor, but gusty
outflow winds remain possible as they push eastward towards the
Colorado River.
On Sunday, mid-level moisture will remain abundant across the
region, though instability will still be quite limited. The end
result is considerable cloud cover to start the day, with the only
exception being our far western zones near the Sierra. Isolated
rain showers will continue, though again more likely sprinkles
and virga than actual measurable rain given the relatively dry
lower levels. A rumble of thunder or two will remain possible.
Clouds will thin out late in the day as drier air works in and
deeper mid level moisture lifts to our north and east.
.LONG TERM...Monday through Saturday.
High pressure shifts westward early in the week, which will
induce a more subsident and dry weather pattern Monday and
Tuesday, and this is when ensemble guidance suggests our regional
precipitable water values will bottom out. As such, fairly
confident on dry conditions area-wide Monday and Tuesday.
Additionally, temperatures will climb several degrees above normal
with parts of the Mojave Desert and Colorado River Valley creeping
into the high heat risk category.
Heat amplifies further late in the week and into the weekend as
high pressure strengthens over the southwest. However, at the
same time, monsoonal moisture pooled in northern Mexico will begin
to creep back into Arizona. This could set the stage for a more
active thunderstorm pattern by next weekend, at least across
Northwest Arizona, and could also influence the amount of warming
we would otherwise see into next weekend. Given the amount of
uncertainty, the forecast remains generally dry through next
weekend, with very hot conditions. Given the upcoming several day
stretch of hot weather, and somewhat elevated dewpoints expected
during the heat spell, high heat risk is a concern and excessive
heat products will likely be considered in future shifts.
&&
.LONG TERM...Monday through Saturday.
High pressure shifts westward early in the week, which will
induce a more subsident and dry weather pattern Monday and
Tuesday, and this is when ensemble guidance suggests our regional
precipitable water values will bottom out. As such, fairly
confident on dry conditions area-wide Monday and Tuesday.
Additionally, temperatures will climb several degrees above normal
with parts of the Mojave Desert and Colorado River Valley creeping
into the high heat risk category.
Heat amplifies further late in the week and into the weekend as
high pressure strengthens over the southwest. However, at the
same time, monsoonal moisture pooled in northern Mexico will begin
to creep back into Arizona. This could set the stage for a more
active thunderstorm pattern by next weekend, at least across
Northwest Arizona, and could also influence the amount of warming
we would otherwise see into next weekend. Given the amount of
uncertainty, the forecast remains generally dry through next
weekend, with very hot conditions. Given the upcoming several day
stretch of hot weather, and somewhat elevated dewpoints expected
during the heat spell, high heat risk is a concern and excessive
heat products will likely be considered in future shifts.
&&
.AVIATION...For McCarran...Mid level moisture moving over
southern Nevada will produce SCT-BKN clouds with bases 12-13 kft AGL
today and tonight but there is very little chance of showers
impacting the terminal area, although an isolated storm can`t be
ruled out over the Spring Mountains this afternoon. Southwest
winds 15-25 kts will prevail into this evening before diminishing,
but still remaining southwest overnight. Southwest winds will
remain in place Sunday, but speeds are expected to be around 10-15
kts. Thunderstorms are expected to develop over portions of
northwest Arizona this afternoon and although they are not
expected to impact southern Nevada, it`s possible that some
southeast outflow winds up to 20 kts could reach the airport this
evening. Confidence is low in this occurring.
For the rest of southern Nevada, northwest Arizona and southeast
California...A southeast flow aloft will bring mid-level moisture
over the region today with SCT-BKN clouds with bases around 15 kft
MSL. Isolated showers and thunderstorms can be expected this
afternoon over portions of Inyo, central Nye, and Esmeralda
Counties. Isolated storms will also be possible across southern
Mohave County. Main threat from these storms will be gusty winds to
35 mph. Outside of any storms, look for southwest winds 15-25 kts
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Salmen
DISCUSSION...Outler
AVIATION...Gorelow
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