Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/02/24
Area Forecast Discussion
National Weather Service Binghamton NY
1009 PM EDT Thu Aug 1 2024
.SYNOPSIS...
Spotty showers and thunderstorms are possible into this evening
west of I-81, otherwise warm and muggy tonight. Hot and humid
conditions are expected again Friday. Shower and thunderstorm
chances increase Friday into Saturday as the next storm system
moves into the region. While not as hot, temperatures will
remain fairly warm through the weekend.
&&
.NEAR TERM /THROUGH FRIDAY/...
930 PM Update...
Conditions have remained mostly dry this evening. An isolated
developed west of our region clipping the northern portion of
Steuben county. Adjusted pops to account for this, while also
adding some patchy fog to the weather grids.
700 PM Update...
Made changes to cut back on pops as showers have mainly
dissipated over our area for this evening. HRRR hints at a
chance of showers creeping back in around midnight ahead of the
warm front. Showers are expected to linger through the early
portion of the morning. This is mainly possible over central
southern tier of NY and northeast PA. Otherwise made the usual
adjustments to update temperatures and dew points with the
latest observations. No other changes needed at this time.
330 PM Update...
Isolated showers and thunderstorms that have developed this
afternoon for our far southern and western counties are expected
to linger into this evening. Any heavier shower or storm has
pulsed up then weakened quickly so any downpours should be
brief. Some high clouds are expected to stream over the area
later tonight ahead of our next approaching storm system, but
some areas of fog are still expected despite the increase in
cloud cover. One or two spots may see a shower overnight as
well, mainly in NE PA. Warm and muggy tonight with lows in the
60s. Portions of the Wyoming Valley and possibly even Syracuse
may fail to drop below 70 degrees.
Clouds are expected to thicken during the mid to late morning
hours tomorrow as an upper level low located over the Ohio
Valley begins to slowly move eastward. A surface warm front
associated with this storm system will lift north across the
area, triggering scattered showers and thunderstorms,
especially after 18Z. With PWATs remaining quite high, generally
between 1.75-2.00 inches, heavy downpours will be possible and
areas that do see any training will have to be monitored for
potential urban/low-lying flooding into tomorrow evening. There
is a marginal to slight risk for excessive rainfall. While the
risk for severe weather seems low, some guidance does show
1000-1500 J/kg and potentially close to 2000 J/kg across
portions of NE PA, but shear appears weak at 25 knots or less,
so a marginal risk for severe storms was added by SPC across the
far southern part of our area.
High temperatures tomorrow are expected to range from the mid
80s to low 90s, but confidence in those values is lower due to
the increasing cloud cover and convection getting underway
during the peak heating hours. Given this uncertainty and
concern, heat headlines were not extended at this time across
portions of CNY, but something that will continue to be looked
at. Lows tomorrow night are again in the 60s to near 70 degrees.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
250 PM Update...
An upper level trough will move from the Ohio Valley late Friday
night into western NY Saturday afternoon, before shearing out
over New England later Sunday. A weak frontal boundary will also
slowly drift east across the area during this time frame. Warm
and humid air ahead of the front will set the stage for showers
and thunderstorms with localized heavy downpours possible ahead
of the front. The area most favored for heavy rainfall will be
across the coastal plain where PWAT values >2 inches will be
most common, but parts of the Catskills and Poconos will also be
on the edge of the deeper moisture.
There is some uncertainty in the eastward progress of the front
on Sunday, with precip chances highest in eastern areas as the
front looks to stall out closer to the coast. The lingering
sheared-out trough may still trigger scattered showers and
thunderstorms, though the risk for heavy rainfall will
diminish.
Seasonably warm but humid conditions will persist through the
weekend, with highs in the middle 80s for most areas.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
250 PM Update...
A fast-moving shortwave trough will graze northern NY on Monday,
with a stronger cold front expected to push across the region
during the afternoon, bringing another round of (generally
lighter) showers and thunderstorms to the area.
Cooler temperatures will filter in behind the front, with highs
expected to drop into the middle to upper-70s by Tuesday,
roughly 3 to 5 degrees below normal. Temperatures will stay
fairly close to this range through the week ahead as troughing
sets up east of Hudson`s Bay in response to a strengthening
ridge over the western CONUS.
A weak disturbance could bring a few showers to the area Tuesday
into Wednesday as deeper westerly flow aloft settles south over
the northern US.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
VFR conditions are expected through 06Z tonight before some fog
begins to develop. There are a few thunderstorms out there this
evening but with only a couple of cells, odds are no terminal
will be impacted. If any rain gets close to a terminal in the
next few hours, the chances of IFR fog will increase for later
tonight with the next update.
Tomorrow will be VFR in the morning between 12Z and 18Z after
the fog dissipates. Widespread showers and thunderstorms develop
after 18Z. Right now left vicinity showers in for all the sights
as coverage and timing of showers and thunderstorms is
uncertain but there is a good chance that there will be storms
near every terminal at some point tomorrow afternoon between 19Z
and 0Z.
.Outlook...
Friday night Through Sunday...Scattered showers and
thunderstorms along with associated restrictions.
Monday and Tuesday...Mainly VFR; low chance of showers and
thunderstorms and associated restrictions.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...DK
NEAR TERM...DK/ES
SHORT TERM...MPH
LONG TERM...MPH
AVIATION...AJG
Area Forecast Discussion
National Weather Service State College PA
1119 PM EDT Thu Aug 1 2024
.SYNOPSIS...
Upper level ridging will build over Pennsylvania until a slow-
moving upper low approaches from the Midwest on Friday. The
upper low will take until late Sunday to pass east of the
state. A dying cold front is likely to sag into the area next
Monday, then stall out in the vicinity of Pennsylvania through
the middle of next week.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Scattered, diurnally-driven convection has largely dissipated
with loss of heating this evening. However, a weak mid level
vort max, initialized in 02Z RAP over the Allegheny Plateau, is
progged to lift across the region overnight. Surging pwats and
a bit of elevated instability ahead of this feature could yet
produce a few showers across the eastern half of the forecast
area overnight. By late tonight, focus shifts to the remnants of
an upstream MCS approaching from Ohio. The chance of showers
and perhaps a tsra will ramp up toward dawn over the W Mtns.
Mostly clear skies for a good portion of the night, combined
with light wind, should result in patchy valley fog overnight.
Latest SREF and NAMNest indicate the earliest onset and most
prevalent fog will be across the N Mtns and in spots that
received rain today. See no reason to deviate from NBM min
temps, which range from the mid 60s over the N Mtns, to the low
and mid 70s across the Lower Susq Valley.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Recent model guidance has latched onto similar timing of the
mid level vort max linked to today`s upstream MCS, all of which
track it across the northern half of PA between 12Z-20Z. Upper
level diffluence and surging pwats ahead of this feature should
result in a round of showers/tsra during the morning across the
western counties and midday to early afternoon in the east. The
strongest forcing and highest POPs are placed across the northern
counties, where the HREF supports POPs around 90pct. Large
scale subsidence behind the vort max, should result in brightening
skies during the afternoon, with only scattered, diurnally-driven
late day convection.
An early arrival of cloud cover and showers should hold temps
and instability in check over especially the western half of
the state Friday. Can`t rule out the chance of severe weather
across the eastern counties, where capes are progged to surge to
around 1500 J/kg by midday. However, poor lapse rates and
unimpressive wind fields support only a marginal risk. The
combination of instability and anomalous (+2SD) pwats is likely
to result in torrential downpours in spots. Convection-allowing
model guidance indicates spot amounts up to 3 inches are quite
possible, which could result in minor flooding. However,
ensemble plumes indicate most places will receive less than a
half inch.
The combination of heat and humidity should briefly push heat
indices into the mid to upper 90s Friday across the Lower Susq
Valley, before the arrival of afternoon convection.
All guidance is pointing toward another round of widespread
convection Saturday in a region of strong large scale forcing
preceding a slow-moving upper low over Ohio. Diurnal heating of
a moist/unstable airmass could yield capes in the 1000-1500
J/kg range by afternoon based on ensemble plumes. GEFS pwats
between 1-2SD above climo, combined with the progged
instability, should result in locally heavy downpours. Ensemble
plumes indicate likely mean areal average rainfall of around a
quarter inch. However, locally higher amounts of > 1 inch appear
very likely based on the environment. Modest mid level flow and
associated shear suggests the threat of organized severe
weather may be limited Saturday. POPs decrease by late in the
day, and some may see a dry evening.
The upper trough and associated plume of anomalous pwats is
progged to pivot across PA by Sunday, placing the eastern half
of the state in line for the best chance of scattered
showers/tsra. Latest guidance suggests a drier westerly flow
behind the exiting trough will result in fair weather Sunday
across the northwest half of the forecast area, along with
decreasing humidity.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A mostly dry and warm to hot Monday looks likely, as anomalous
850mb temps surge into PA ahead of a weakening cold front over
Southern Ontario. The GEFS is more progressive with the front
and supports the chance of PM convection across Northern Pa,
while the EPS keeps the front further north, resulting in dry
weather. Most medium range guidance develops an upstream wave
on the stalled front, tracking it across Central PA Tues PM into
Wed. This scenario supports a decent chance of showers/tsra
in the late Tuesday to Wednesday timeframe.
Odds appear to favor fair weather with near to slightly below
normal temperatures during the second half of next week
associated with high pressure building across the Grt Lks.
However, there remains some uncertainty with regard to how far
south Wednesday`s cold front gets before stalling out.
Therefore, can`t rule out scattered PM convection into Thursday,
mainly over Southern PA.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
A majority of the the afternoon convection has trended downward
across the central PA region. Thus the mention of VCSH has been
removed from the TAFs for the remainder of this evening. An
isolated shower could still crop up over airfields in eastern PA
during the early evening hours, but probability is too low to
mention them in the TAF package.
Expect fog for form mainly across the northern tier of PA, with
model guidance outlining BFD and IPT with the highest potential
for sub-VFR conds. IFR restrictions seem most plausible after
10Z Friday, with a brief period of MVFR conds possible in the
08-10Z timeframe, with IFR conds continuing towards sunrise
Friday morning.
Scattered SHRA/TSRA are possible again across central PA on
Friday, with impacts most likely at BFD/JST before 18Z Friday.
The 00Z TAF package has outlined these in PROB30 groups due to
some uncertainty in timing/coverage with future forecast
packages potentially having more confidence. These showers and
thunderstorms will become more widespread throughout the
afternoon, eventually reaching the far SE airfields near 20Z.
Outlook...
Sat-Sun...Periods of showers and storms expected over the
weekend.
Mon...Lingering scattered TSRA/SHRA with a stationary front to
the north.
Tue...Scattered SHRA/TSRA mainly NW PA, restrictions possible.
&&
.CLIMATE...
A daily maximum rainfall/precipitation record was set for
Harrisburg, PA. A record rainfall of 2.3 inches occurred over
the past 24 hours at the Harrisburg, PA airport. This breaks
the old record of 2.04 inches of rainfall set in 2004. A
continuous weather record has been kept for Harrisburg since
1888.
The mean/average temperature for July for Harrisburg was 80.2F,
making it the 5th warmest July on record there.
The Harrisburg mean temperature for June and July combined is
78.1F, which is the warmest June & July on record. For
Harrisburg to achieve the warmest Summer (JJA) ever, they`ll
need an Aug mean temp of 77.9F or greater. That would take a
top-7 finish for Aug alone (warmest Aug ever is 2016 at 79.1F).
The mean temperature since January 1st at Harrisburg is 56.8F,
which makes it the warmest year-to-date on record.
While July 2024`s mean temp at Williamsport (76.4F) was not
quite in the top-10 warmest, it did contribute to the 54.4F
year-to-date mean temp which makes it the warmest year-to-date
(Jan-Jul) on record there.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT Friday for PAZ036-056-057-059-
063>066.
&&
$$
SYNOPSIS...DeVoir/Dangelo
NEAR TERM...Fitzgerald
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...Fitzgerald
AVIATION...NPB/Bowen
CLIMATE...Evans/Steinbugl/Banghoff
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
331 PM PDT Thu Aug 1 2024
.SYNOPSIS...Isolated thunderstorms are possible over the interior
Friday night and Saturday. Otherwise, hot and dry weather is
expected in the interior for the next 7 days.
&&
.DISCUSSION...The marine layer remained compressed and shallow
today, around 1000 feet deep at the ACV profiler. Stratus has
been lingering along the immediate shoreline and over the beaches
through the day. This layer will most likely remain shallow and
confined to mostly coastal areas for the next couple of days and
nights. There will be diurnal pushes each day and stratus will
likely reform in adjacent coastal river valleys each evening after
burning off by mid morning. Otherwise, interior temperatures are
forecast to remain well above normal through the weekend with
temperatures projected to peak in the upper 90`s to 105F. Heat
risk is forecast to be moderate. This level of heat could impact
individuals sensitive to heat and/or those without adequate
hydration and cooling.
Uncertainty with temperatures arises Friday into Saturday as
mid/high level clouds spread over the area from the SE. It is
highly probable that temperatures will remain above normal on
Friday and Saturday. PWATs will increase over 1 inch Friday
evening and overnight and some light showers are possible,
though all the water vapor is nearly entirely above 10,000-15,000
feet. The concern will be the potential for thunderstorms and
dry lightning strikes. HREF, SREF and NBM calibrated guidance
indicate very little or no chance for storms until Saturday over
NE Trinity. Deterministic CAMS indicate 30-35dbz cores spreading
over the area Friday night and a few isolated strikes are not
completely out of the question. 12Z ECMWF deterministic sounding
also indicates CAPE over 500J/kg developing early Saturday
morning over interior southern Humboldt, southern Trinity and
interior northern Mendocino. NAM and GFS soundings were much more
stable. There is a disturbance at mid levels that may serve to
provide the upward motion necessary to trigger storms. LFC`s are
quite high, over 5kft AGL, and even though PWATS are over 1 inch,
isolated dry strikes are possible. Confidence in abundant
lightning activity is by no means high. SREF calibrated lightning
probabilities for over 100 cloud to ground strikes are highest
north in southern Oregon. ECMWF lightning flash density also has
northern Trinity County on the fringes of highest density. HRRR
lightning density has been consistently indicating a swath
lightning spreading into eastern Lake, northern Mendocino and
most of Trinity as early as Friday evening. This activity may
track northwestward into eastern Humboldt and eastern Del Norte
later Friday night or early Saturday morning. Thunderstorm
activity should shift into primarily NE Trinity County Saturday
afternoon and evening. Storms should eventually become wetter
by this time, and locally heavy rain and hail are possible.
Ensemble means and clusters indicate 500mb ridge dominating all
of next week. Hot and dry weather will likely continue in the
interior. Heat risk is forecast to remain moderate. It remains
uncertain if we are going have another major heat wave with highs
of 110F or more. Coastal areas will remain cooler with the usual
stratus and fog, primarily during the night and morning hours.
DB
&&
.AVIATION...Improving flight categories continue this afternoon at
KACV and KCEC as overcast skies scatter out. VFR may only be
shortlived as a strong inversion persists through the next TAF
period, translating into a return of LIFR conditions overnight at
the coastal terminals. Drizzle and lower visibility are likely to
return as the compressed marine layer forces coalescence. Ceilings
are lifting out of their sub 500 foot stagnation but will remain
under 1500 - 2000 feet as the return of stratus is being signaled by
MOS and HREF. Satellite in the visible spectrum also shows marine
stratus directly offshore with some reversal flow near shore, but
thinning out rather than socking in the terminals as of 20z. Model
soundings show a distinct saturated surface with inversion through
the Friday morning hours with drizzle likely, so expect marine
stratus return by the early evening at KCEC and KACV. /EYS
&&
.MARINE...Nearshore seas are reporting around 4 feet with sustained
winds at 4 - 8 knots. Elevated gusts of 18 - 22 knots are expected
to develop downwind and nearshore of Cape Mendocino late tonight and
into early Friday morning. Strong subsidence continues to compress
the marine layer and pose higher risk for dense fog and reduced
visibility. Increasing interior temperatures will continue to
enhance the coastal pressure gradient this weekend, with gusts 20-30
knots and low-end advisory level seas possible in the southern and
outer waters late Friday through early Sunday. Models are a bit
inconsistent but have indicated additional and more substantial
surges in coastal winds are by mid next week as high pressure
remains dominant. /JMM /EYS
&&
.FIRE WEATHER...Main change was to expand isolated thunderstorm
threat across most all interior zones Friday night into Saturday
morning. Main threat after Saturday morning shifts into NE Trinty
County. Isolated dry thunderstorms are possible (10% chance)
Friday night into Saturday morning as a surge of monsoonal
moisture spreads over the area. An upper level disturbance is
expected to track over the area late Friday night into Saturday
morning and could trigger thunderstorm activity over much of the
interior. Confidence is by no means high there will be abundant
lightning activity, however any strikes on dry fuel beds will
result in new ignitions.
Otherwise, hot weather with daytime RH`s of 10 to 20 percent is
expected for the next 7 days. RH`s were lower today and upslope
and upvalley winds have been a bit more gusty with a few sites
gusting to 25 to 30 mph in the interior. A few hours of critical
are expected. Winds are expected to diminish overnight and
good recoveries are generally expected. The exception will be
over higher elevations and within the thermal belt of Lake and
Mendocino counties where humidity recovery of 30% or less is
likely. This will probably continue for the next several days,
through Friday night may have slightly better recoveries if spotty
light showers or sprinkles occur. Winds are forecast to remain
diurnally driven with upslope and upvalley gusts up to 20 mph each
afternoon for the next 7 days. An upper trough will approach on
Sunday and probably result in locally stronger upslope/upvalley
gusts (to 30 mph) Sunday and Monday. DB
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
None.
&&
$$
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For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png
Area Forecast Discussion
National Weather Service Indianapolis IN
928 PM EDT Thu Aug 1 2024
.KEY MESSAGES...
- Patchy dense fog mainly near and to the southeast of I-69
- A few more thunderstorms possible tonight
- Flooding will continue, mainly across eastern parts of the
Metro
- Heat indices near 100 degrees this afternoon south of Interstate 70
- Generally quiet and warm this weekend into next week
&&
.FORECAST UPDATE...
Issued at 924 PM EDT Thu Aug 1 2024
The widespread convection we had this afternoon and evening as left
areas near and southeast of Interstate 69 very worked over. In fact,
winds have become light to calm and the RH was already 100% over
much of the area. In addition, patchy dense fog was already
developing. That said, upstream cold front and trailing trough and
CAPEs over 2000 J/kg over the Wabash Valley could bring some
improvement as the night goes but some Hi_RES models suggest fog
could be a problem all night. For now, feel the best option is to
add patchy fog to the grids in the area of concern and also mention
it in the HWO and perhaps in an SPS.
Otherwise, will leave small thunderstorm chances in due to the
increasing synoptic component and radar and CAMs trends. Clouds will
generally decrease from west to east except briefly in convection
and perhaps stratocu development due to the moist boundary layer and
shallow inversion. Temperatures will not fall much at all based on
70+ dew points.
&&
.MESOSCALE UPDATE...
Issued at 506 PM EDT Thu Aug 1 2024
Focus has shifted over the Indy Metro area for slow moving
convection. Atmosphere remains moisture rich through the lowest
layers, with dewpoints still hovering in the mid/upr 70s. A cluster
of convection has developed earlier northwest of Indy, and continues
to slowly propagate east. This is all positioned along the gradient
where DCAPE is maximized, the slope of the lapse rates is also found
in this zone, which is allowing some of the vertical growth to
slowly increase. A few of the stronger towers have been able to
collapse and produce gusts to around 40 mph, but it`s conceivable
that some stronger towers may occur over the next few hours and
continue to increase towards low-end severe or near 60 mph.
The bigger concern at the moment is on flash flood potential in this
area around Indy Metro, given the very sluggish movement to this
area of convection, and the high buoyancy to the atmosphere, flash
flooding concerns will be elevated through this evening as this
cluster slowly propagates northeast.
Previous Mesoscale discussion issued 412pm edt...
Quasi-linear line of convection developed earlier this afternoon in
Southern IL and continued to propagate east into Southwest IN and
Western KY. Moisture rich environment ahead of this convection with
an axis of dewpoints in excess of 75 degrees for a good portion of
Southern IN. The last hour has observed winds remain chaotic with a
light flow less than 5-10knots. The main feature positioned from
Indianapolis south to the Central KY is the zone of increased DCAPE,
which can be a bit of a concern for rain cooled downdrafts helping
to transfer higher winds aloft to the surface and cause a wind
threat. Mid-lvl lapse rates appear to have relaxed marginally in
this zone of higher DCAPE, albeit still somewhat sloped but with the
depth of warm air that is equally moist, it could be difficult to
have sustained convection that reaches severe limits on a more
widespread nature. The effective shear is not much to be
concerned with at the moment either, but when looking at the
0-6km layer there def is an elevated wind field. This being
said, the atmosphere can become modified due to ongoing convection
and the steady forward propagation to the QLCS could overcome this
and still pose concerns for severe winds.
Visible satellite imagery depicts the expansive cloud shield that
now covers much of Indiana, but still seeing some vertical growth to
the cumulus field in extreme Southern IN near Louisville. Further
north the cirrus shield appears to be helping to cap the vertical
movement to parcels, but there remains the potential east of Indy
for seeing the late afternoon/early evening isolated convection
develop. But confidence appears to have been muted slightly due to
the cirrus clouds overhead.
Flash flooding concerns could still be a concerns in the far
southern CWA, more so with the large droplets and efficiency to the
convection. This could easily produce high instantaneous rainfall
rates in a short period of time, and thus lead to some isolated
flooding concerns mainly east of Knox County over the next couple of
hours before convection exits the region to the east/southeast.
Previous Mesoscale AFD issued at 129 PM EDT... Thunderstorms
developing over SE IL are expected to continue to propagate east
into southern Central Indiana through the afternoon hours. An
outflow boundary from morning storms is laying across southern
Indiana, just south of Knox/Lawrence and Jennings counties. Airmass
south of this area remains quiet favorable for devlopment. North of
the boundary, CIN is decreasing rapidly as dissipating clouds are
allowing heating into the mid 80s. This will continue to weaken the
lower level cap across the area.
ACARS soundings show steep lapse rates available above the CAP
within the mid levels. This will allow access to CAPE at or above
2000 J/KG across much of southern Central Indiana. HRRR continues to
suggest development across central Indiana, reaching the Wabash by
18Z-19Z, crossing southern Central Indiana through 24Z.
Some uncertainty remains on storm development on the northern side
of the storms. As heating progresses, conditions should become more
favorable across points to the north, but for now, severe storms are
not expected north of the watch area. However, non-severe storms
will be expected for the IND Metro. Should conditions become more
favorable across points to the north of the watch, the watch will be
expanded to the north.
Main threats this afternoon will be damaging wind gusts. An isolated
tornado cannot be ruled out.
&&
.SHORT TERM (This evening through Friday)...
Issued at 224 PM EDT Thu Aug 1 2024
Rest of today and tonight...
Another round of strong to severe convection will impact at least
southern portions of central Indiana this afternoon, with a quasi-
linear cluster of high-topped severe cells in the vicinity of an MCV
over southern IL...entering the Lower Wabash Valley as of 17Z.
Gradient in cloud cover between ample sunshine south of Interstate
70 to generally BKN skies across the region`s northern half...will
guide convective development and intensity through 00Z. SVR Watch
out along and south of a Sullivan-Bloomington-Greensburg line
matches expectations of increasing thunderstorm coverage this
afternoon...where the very humid air is now heating into the upper
80s, producing up to 2000-3000 J/kg of CAPE.
Outflow boundary from pre-dawn convection current aligned west-east
near the CWA`s southern edge may serve to limit return of best theta-
E/instability from the Ohio Valley into our southern realm...yet may
also enhance storm relative helicity in its vicinity. Cannot rule
out a quick spin-up, focused south of US-50...yet widespread
strong/severe straight line winds and perhaps inordinate lightning
will be the main threats. Expect convection to increase over the
rest of the region`s southern half, although severe threat here is
much more conditional. Storm motion from west to east in mainly the
25-40 KT range should discourage flash flood potential, although any
locations subject to 2-3 rounds of TRWs may experience isolated
flooding.
Rain/storm chances to eventually decrease tonight as the approaching
mini-wave pushes better deep moisture to our east. Yet, expect
scattered convection to continue over parts of the region into this
evening, with isolated strong/severe winds possible, and a slightly
greater flood threat after what may have been a couple hours of
heavier rainfall rates over a few areas. Dewpoints in the low 70s
will once again guide matching overnight low temperatures..with
patchy to areas of fog expected where moderate to heavy rainfall has
occurred.
Friday...
The weak northern stream vort, along with a modest surface low
reflection, will slowly cross the Midwest as the work week ends.
Lower heights and SCT/BKN decks will oversee what should be isolated
ordinary convection...which may become more scattered during late
day hours following diurnal heating. The SPC Marginal threat is a
good first approximation as brief stronger winds cannot be ruled out
with adequate CAPE and 500 J/kg of DCAPE. Any marginally strong
winds would be favored across far northern zones where the passing
center of the upper spin will promote the only region of decent mid-
level lapse rates and CAPE approaching 1500. Despite higher
humidity continuing...light breezes backing to west-northwesterly
will work with the heights/clouds to bring sub-80 maxima to several
northern counties, and likely only low 80s along far southern zones.
&&
.LONG TERM (Friday night through Thursday)...
Issued at 224 PM EDT Thu Aug 1 2024
Friday Night Through Sunday.
By Friday night the last of the waves that have brought these
multiple rounds of severe storms to the Ohio Valley will be exiting
with only a few lingering showers expected into early Saturday. As
the rain chances come to an end, heat associated with the gradually
strengthening ridge will become the primary weather concern as the
daily storm chances come to an end with the associated relief from
the heat. Surface high pressure will help to keep things dry into
Sunday.
Monday Through Thursday.
The periphery of the upper level ridge will be oriented more towards
the Great Lakes region early next week which should keep the
majority of the rain chances keeping to the north of the forecast
area and keeping temperatures near to slightly above normal through
the early portions of the week. An outflow boundary could
potentially sink to the south of any storm complexes and cause
thunderstorm initiation across central Indiana, but confidence is
fairly low at this time. Towards late week, confidence is increasing
in a colder stretch of weather going into the following week with
the potential for highs in the 70s and lows in the 50s.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 627 PM EDT Thu Aug 1 2024
Impacts:
- Thunderstorms along with MVFR and worse conditions in convection
are mostly like through 02z at KIND and KBMG and after 15z Friday
- MVFR and perhaps brief IFR ceilings and visibilities possible
09z-13, especially at the smaller airports
Discussion:
Mostly scattered convection is possible through Friday morning,
ahead of a cold front to the northwest. Will hold off from putting
convection in the TAFs tonight based on radar and CAMS trends. The
exception will be KIND and KBMG, where a tempo thunderstorm grouped
was introduced through 02z Friday. Otherwise, increasing chances for
convection Friday afternoon moves through and interacts with
increasing instability.
Winds will be light southwest to calm tonight and northwest to near
10 knots Friday as the front passes.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...MK
SHORT TERM...AGM
LONG TERM...White
AVIATION...MK
Area Forecast Discussion
National Weather Service Medford OR
819 PM PDT Thu Aug 1 2024
.DISCUSSION...Satellite imagery is suggesting some coastal stratus
and a few high clouds this evening. Smoke from area wildfires
remains over the area, but winds are beginning to funnel the smoke
eastward. The HRRR smoke model has struggled so far this season
with modeling where the smoke is going, but overall the forecast
which relies heavily on the HRRR Smoke model seems to be
reasonable. Will allow the forecast to ride for now.
The upcoming pattern looks to be very dynamic with heat and
thunderstorms in the forecast. There are some limiting factors to
take into account in the forecast to include cloud cover and
smoke. More details on this in the previous discussion below.
-Schaaf
&&
.PREV DISCUSSION... /Issued 520 PM PDT Thu Aug 1 2024/
DISCUSSION...Stratus is still present at the coast and offshore,
and is farthest inland near Pistol River, Bandon and Coos Bay.
Current satellite shows the smoke from the fires in Lane County
has moved into Douglas County including Roseburg and is holding
steady in the area with visibility near 4-6 miles. This smoke will
remain in eastern Douglas and northern Klamath and Lake Counties
through tomorrow. Smoke from the Park Fire has made it into
northern California and Southern Oregon and will move east to east
of the Cascades tonight. The current concentration of smoke is
the worst for the Rogue Valley and east into Klamath Falls, and
this will continue until tomorrow when it moves farther east. With
the continued issue of worsening air quality, an Air Quality
Alert has been issued through Friday morning for Jackson, Klamath
and Lake counties. Intermittent smoke is possible in Josephine and
Eastern Douglas counties.
The heat peaks this afternoon with highs from the mid-70s at the
coast in the triple digits for west side valleys (including the
Klamath River and Shasta valleys). East side highs will also reach
the upper 90s in more locations. Temperatures will not recover much
overnight, and there is a less than 10% probability for Medford to
fall below 65 degrees tonight with a 10-20% probability tomorrow
night as well. With this heat and minimal recovery during the
overnight hours in mind, a Heat Advisory will be in effect through
Saturday morning for west side valleys.
Checking back into cloud cover, there will be stratus once again at
the coast that will likely reach into parts of the coast once again.
Southerly winds have been present today and will continue into
tonight. There will be an increase in high clouds that come from the
south through the day tomorrow.
Thunderstorms are in the forecast starting tomorrow afternoon.
The main area with this slight chance will be the Cascades, northern
Klamath County and parts of Siskiyou County. This trend continues
with more confidence on seeing thunderstorms in northern Lake and
Klamath counties Saturday afternoon with SPC guidance showing a 40-
50% probability of thunderstorms in the area. Ensembles are showing
that areas east of the Cascades could see a few hundreths for
rainfall, and overall less than a tenth of an inch is in the
forecast, although locally higher amounts are possible. The main
change for the thunderstorms in this forecast package has been to
add a slight chance of thunderstorms tomorrow night through Saturday
evening for most of Jackson County and eastern Douglas. Forecast
soundings at Medford are favoring 500-1,000 J/kg DCAPE with PWATs
near 0.90"-1.20", and 15-30 knot 0-3 km shear for parts of Friday
night/Saturday afternoon. With an "inverted-V" sounding that is
forecast, it will be harder to get healthy rains to reach the
surface. However, DCAPE values with the shear will bring a strong
wind threat to passing thunderstorms.
-Hermansen
AVIATION...02/00 TAFS...VFR conditions will prevail over interior
southern Oregon and northern California, except for MVFR conditions
in smoke/haze in the vicinity of area fires. Model simulations of
smoke haven`t been that helpful, but indicate the vast majority of
the impactful smoke will be from the Cascade Foothills of eastern
Douglas County eastward into Klamath/Lake counties and across NE
California (Modoc) tonight into Friday. Some of these areas
could see IFR or lower at times. All of the terminals at Roseburg,
Medford and Klamath Falls will see some visibility reductions due to
wildfire smoke/haze into Friday afternoon, generally in the 3-6 mile
range.
Widespread IFR/LIFR marine stratus extends up and down the coast and
offshore this evening and this will continue during the night and
into Friday. The marine layer will deepen a bit compared to last
night, so should push a bit farther inland, but probably not as far
as Roseburg. -Spilde
MARINE...Updated 200 PM Thursday, August 1, 2024...Low clouds with
patchy drizzle and reduction in visibility will be the norm,
especially in the overnight into the morning hours through the
weekend. Relatively calm conditions are expected through Friday
night. However, some of the models hint at some elevated instability
moving into the waters Friday night into Saturday morning. This
could result in an isolated thunderstorm or two over the marine
waters. This is not a slam dunk, but something that we`ll have to
keep a close eye on. Winds will increase some Saturday from an
expansion fan between Cape Blanco and Gold Beach that could reach
low end Small Craft. A stronger thermal trough is likely to develop
next Tuesday and persist into next Thursday, with at least Small
Craft conditions south of Cape Blanco and possibly low end gales
south of Gold Beach. -Petrucelli
FIRE WEATHER...Issued 200 PM Thursday August 1, 2024...Strong high
pressure continues over the region today, bringing another round of
low daytime humidities with triple digit temperatures for West
Side Valleys, and mid-upper 90s for East Side. High temperatures
are expected to peak today, and this is also when we expect
daytime humidities to bottom out. Southerly flow will enhance
afternoon breezes today, especially east of the Cascades and in
the Shasta/Scott Valleys. This will result in near critical
conditions for much of those areas, with the Shasta/Scott and
southern OR Cascades expected to reach critical conditions this
afternoon. A Red Flag Warning for gusty winds and low RH remains
in effect through 8 pm this evening. Recoveries will trend lower
again for Friday morning, with recoveries expected to improve
Saturday and Sunday mornings with the influx of monsoonal
moisture.
All the ingredients are lining up for a thunderstorm event beginning
late Friday night and continuing into Saturday evening. A push of
monsoonal moisture will move into the region Friday
afternoon/evening, followed by a rather potent shortwave late Friday
night into Saturday morning. Typically we look for three things to
come together for thunderstorm initiation: moisture, trigger,
instability. We have high confidence for two of the three elements
(moisture, trigger) to be in the region late Friday night. The
instability parameter, however, looks marginal at this time, which
is leading to low confidence in thunderstorm coverage during the
overnight hours. While models are showing an area of showers moving
northward into the region late Friday night/early Saturday morning,
the lack of instability depicted by models lends to the idea that it
may just be an area of showers with embedded isolated lightning that
occurs during the pre-sunrise hours on Saturday. We`ve introduced a
slight chance for thunderstorms (15%) across portions of Jackson and
eastern Douglas Counties to account for this potential, with
showers/thunderstorms initially moving into northern California
Friday night, then moving north/northeastward into southern Oregon
early Saturday morning.
There is some uncertainty regarding Saturday afternoon`s convection
due to potential cloud cover from the morning time activity. If
cloud cover lingers too long, it could limit the amount of daytime
instability available for thunderstorm initiation. Guidance shows
the cloud cover moving northward early enough in the day, however,
for another round of showers/thunderstorms to develop Saturday
afternoon. This is when we expect the greatest coverage in
thunderstorm activity (scattered or greater), especially along and
east of the Cascades. While some isolated activity is possible
along and east of the I-5 corridor Saturday afternoon, confidence
was higher for the issuance a Fire Weather Watch for abundant
lightning on dry fuels for the Cascade zones and eastward. This
includes FWZs 617/623/624/625/285/284/280. Confidence is a bit
lower for zone 280 considering midlevel moisture may be out of
that area by the time Saturday afternoon rolls around. However,
western Siskiyou County tends to be a hot spot for convection, so
included that area as a precaution.
This thunderstorm event will differ from ones previously in the
season so far in that the moisture layer will be fairly deep with
this monsoon push. PWATs will increase to over an inch, even
reaching 1.5 inches in some places west of the Cascades with 0.75"-
1.00" for areas east of the Cascades. Initially, Friday night into
early Saturday, storms will be a wet/dry mix...more on the dry side,
then trending wetter as the day progresses Saturday. Despite the
expectation of storms producing measureable precipitation (maybe
even wetting rain under the storm cores), lightning strikes outside
of storm cores are expected and will be cause for concern. In
addition, strong gusty outflows are expected with any thunderstorms,
with winds gust of 40 to 50 mph a real possibility.
The thunderstorm threat diminishes on Sunday, but does not come to
an end. The midlevels will begin to dry out with enough moisture
lingering across the northeastern area and Modoc. This is where we
anticipate some isolated activity to continue on Sunday. /BR-y
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory until 8 AM PDT Saturday for ORZ023-024-026.
Fire Weather Watch from Saturday morning through Saturday
evening for ORZ617-623>625.
CA...Heat Advisory until 8 AM PDT Saturday for CAZ080-081.
Fire Weather Watch from Saturday morning through Saturday
evening for CAZ280-284-285.
PACIFIC COASTAL WATERS...None.
&&
$$
Area Forecast Discussion
National Weather Service San Francisco CA
442 PM PDT Thu Aug 1 2024
...New AVIATION, MARINE...
.SYNOPSIS...
Issued at 1250 PM PDT Thu Aug 1 2024
Warmer than average temperatures will continue through the
forecast period. There is a slight chance for light showers or
dry thunderstorms Friday evening.
&&
.SHORT TERM...
(This evening through Friday)
Issued at 1250 PM PDT Thu Aug 1 2024
A building ridge will be briefly interrupted by a transient plume
of moisture and vorticity originating from the northern end of an
easterly tropical wave that spawned tropical storm Carlotta
yesterday. This mid-level moisture is already bringing showers to
southern California and will continue to push north over the next
36 hours. The dry lightning potential remains low at 5%, but it
does look more likely that some light showers could push through
Fri evening. This change is based on a big increase in composite
reflectivity on the 18Z HRRR run (compared to the 12Z run), as
well as the fact that southern California is already seeing some
showers (no lightning yet) from this system. It seems the high
PWAT is enough to overcome the dry low levels pretty effectively.
We will have to keep an eye on Southern California to see if any
thunderstorms develop later this afternoon to get a better idea
what tomorrow will look like in the Bay Area.
&&
.LONG TERM...
(Friday night through next Wednesday)
Issued at 1250 PM PDT Thu Aug 1 2024
Temperatures will hold roughly 5 degrees above normal through the
forecast period. In fact, there has been a slight improvement
through the weekend, with ECMWF ENS 850 temp run-to-run decreasing
by around 1C over the last couple updates. This is likely in
response to increased cloud cover from the moisture plume. Areas
in the interior East Bay, South Bay, and interior Central Coast
will begin to see moderate HeatRisk by early next week, not
necessarily due to the magnitude of the heat, but rather many
consecutive days above normal. With the risk of heat-related
impacts remaining limited and the trend improving, we are still
holding off on the issuance of any hazards.
The shower/thunderstorm/dry lightning threat will continue
through Friday night. There`s a possible return Saturday
afternoon, though Friday looks more likely at this time. By
Sunday, the threat will have passed.
&&
.AVIATION...
(00Z TAFS)
Issued at 426 PM PDT Thu Aug 1 2024
Currently VFR at all terminals with stratus off the coast. High
confidence that all terminals with the exception of LVK will
develop an LIFR-IFR ceiling tonight. Thanks to high pressure, the
marine layer will remain compressed and slant range visibilities
will likely be impacted due to haze and smoke. Tomorrow afternoon
poses the chance (<5%) for thunderstorms across the area; however,
confidence was not high enough to include any precipitation
descriptors in the TAFs at this time.
Vicinity of SFO...Currently VFR with northwesterly flow. Winds will
prevail out of the west/northwest through the TAF period. High
confidence on an IFR ceiling to impact the terminal tonight through
late-morning tomorrow.
SFO Bridge Approach...Low clouds will filter in by 04Z and linger
through 19Z.
Monterey Bay Terminals...Currently VFR with northwesterly flow at
both terminals. Winds will prevail out of the west for MRY and out
of the west/northwest for SNS through the TAF period. High
confidence in LIFR ceilings impacting both terminals tonight through
tomorrow morning.
&&
.MARINE...
(Tonight through next Tuesday)
Issued at 426 PM PDT Thu Aug 1 2024
The gradient between subtropical high pressure and lower pressure
over California is supporting a moderate NW breeze and moderate
sea heights across the waters. This gradient will tighten over the
weekend, increasing winds to a fresh breeze and building sea
heights up to 8 ft. While not forecast to be of much impact to
our area, Tropical Storm Carlotta, along with two other
disturbances, are churning in the Eastern Pacific. We will
continue to monitor the tropics to see if any significant
southerly swell is on the way.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM to 9 PM PDT Friday for Pt Arena
to Pt Reyes 0-10 nm.
Small Craft Advisory from 3 PM Friday to 3 PM PDT Saturday for
Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60
NM.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Sarment
MARINE...Flynn
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Area Forecast Discussion
National Weather Service Nashville TN
828 PM CDT Thu Aug 1 2024
...New UPDATE...
.UPDATE...
Issued at 814 PM CDT Thu Aug 1 2024
Currently monitoring a severe storm just to the northwest of
Clarksville. Brief gusty winds might be possible along with
frequent lightning and heavy rain. Other than that, radar trends
indicate shower and thunderstorm activity is waning and after
about 04Z should come to an end. HRRR has been inconsistent with
the coverage of storms this evening, but depicts activity for the
Upper Cumberland Plateau during the overnight hours. Something to
monitor, but no severe weather is expected for this area.
&&
.SHORT TERM...
(Rest of today through Saturday)
Issued at 1059 AM CDT Thu Aug 1 2024
Finally. We are out of the northwest flow aloft. That doesn`t mean
we won`t see a few storms over the next couple of days, but
hopefully it will lead to a little more model continuity. Showers
and storms from earlier this morning over the Cumberland Plateau
have moved into East TN leaving us with mostly sunny skies. We
are seeing the usual cu development this time of the morning, but
I think the bulk of what we`ll be dealing with through 00Z will be
the heat. Heat Advisories are still posted through the afternoon
hours with Heat Index values expected to climb towards 110
degrees. As our student volunteer put it, it`s just terrible.
However, *some* relief is in sight. Before we get there though, a
couple more rounds of storms are in store for the mid-state.
Starting this evening, latest CAMs are pretty consistent showing
some storms moving into our northern counties. Obviously, as with
any of our summertime storms, wind and heavy rain will be a risk.
How far south they push is still in question, but they will be
associated with a weak boundary that is part of an upper level low
over the Great Lakes. Influences from this upper low and boundary
will be around Friday and Saturday in the form of scattered
showers and storms. Models have been pretty consistent depicting
the bulk of the PoPs to be along and east of I-65 both days.
Doesn`t negate a rogue storm closer to the TN River, but chances
are lower. Again, heavy rain and wind will be a risk with any of
these storms, but most should revolve around diurnal influences.
This should relegate most of the activity to the afternoon and
early evening hours. The other fantastic change that will come
with this upper low is that the upper ridge responsible for the
heat of the last few days will retrograde back over the western
part of the country allowing for temperatures to fall back closer
to seasonal averages Friday and Saturday. There`s your relief.
&&
.LONG TERM...
(Saturday Night through next Thursday)
Issued at 1059 AM CDT Thu Aug 1 2024
By Sunday, while rain chances will be east of us, a couple of things
may be going on. First, medium range guidance is starting to come
into better agreement on tropical activity in the northern Gulf of
Mexico. How strong that tropical activity will be is yet to be seen,
however, with that to our south and high pressure pushing back into
the region from the west, afternoon highs may very well push back
into the mid to upper 90s once again. We`ll have to see how these
numbers play out. If this current medium range guidance pans out and
we have north to northeast boundary layer flow over the TN and Ohio
Valleys, afternoon highs could creep towards triple digits.
Especially if any tropical system intensifies. Because of the
tropical influences and low confidence in this time frame,
extended guidance confidence is even lower.
&&
.AVIATION...
(00Z TAFS)
Issued at 616 PM CDT Thu Aug 1 2024
A band of showers and thunderstorms will move into the mid-state
early as depicted by current radar trends. Will have to watch
conditions but brief MVFR VIS or CIGS might be possible. After
about 04Z expect VFR conditions, with more westerly winds after
15Z tomorrow.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 77 94 72 92 / 40 50 10 10
Clarksville 75 90 70 90 / 40 30 10 10
Crossville 70 86 65 83 / 40 70 30 40
Columbia 76 94 71 91 / 20 40 10 10
Cookeville 73 86 68 83 / 50 70 30 20
Jamestown 71 85 66 82 / 50 80 40 50
Lawrenceburg 75 93 70 90 / 20 50 10 10
Murfreesboro 76 94 71 91 / 30 60 10 10
Waverly 75 93 70 91 / 40 20 10 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......05
SHORT TERM...05
LONG TERM....Unger
AVIATION.....05
Area Forecast Discussion
National Weather Service Pocatello ID
148 PM MDT Thu Aug 1 2024
.SHORT TERM...Today and Friday.
High pressure will build in across the area today and tomorrow
with model guidance in very good agreement. The ridge axis looks
to be directly over southeast Idaho by Friday. Temperatures will
be a couple degrees above normal today and rise even higher
Friday, 4 to 8 degrees above normal. There will a few locations,
especially near Shoshone, that may hit 100 degrees. Most lower
valley locations will be in the mid to upper 90s by Friday
afternoon. Have put out a heat advisory for Friday and Saturday
for most valley locations across southeast Idaho. Have kept patchy
smoke in the forecast as smoke in southerly and southwesterly
flow is expected to move back into the area, especially later
today and, more so, on Friday.
Wyatt
.LONG TERM...Saturday through Next Thursday.
The long term forecast kicks off with our Heat Advisory that will
continue through Saturday evening thanks to high pressure overhead.
There is a 40 to 50 percent chance of reaching 100 degrees on
Saturday for areas near Shoshone, out across parts of the Arco
Desert, and the lower Snake Plain. Even those who don`t quite hit
100 degrees will be hot, reaching the mid to upper 90s. A weak
shortwave moves through the area and flattens the ridge enough for
our highs to drop a few degrees (still in the low to mid 90s) and to
start introducing light PoPs into the forecast late Saturday through
Sunday. Monsoon moisture will stick around through the better part
of next week, though Monday looks to bring a more widespread 20 to
40 percent chance of showers and storms. Highs will mostly hold in
the low to mid 90s through the first half of the week before
dropping a couple of degrees into the upper 80s and low 90s by
Thursday afternoon. Winds are forecast to begin increasing next week
with gusts approaching 25 to 30 mph for Tuesday, Wednesday, and
Thursday afternoons.
AMM
&&
.AVIATION...18Z Thursday through 18Z Friday.
High pressure overhead continues to drive our weather today and
Friday. Winds will remain light and variable with VFR conditions
expected today. The latest HRRR smoke modeling shows more light to
moderate smoke from area wildfires moving back into all TAF sites
this afternoon and evening, though it looks lightest at DIJ. Even
with some smoke returning, the HRRR doesn`t want to reduce VIS at
all. No impact at all to VIS seems a bit optimistic from the models,
so will continue to run with the 6SM HZ/FU.
AMM
&&
.FIRE WEATHER...High pressure will dominate the area through the
weekend. Look for hot, dry and, unstable conditions today through
most of Saturday afternoon. By late Saturday afternoon monsoon
moisture will likely move back into the area bringing back a
chance of late afternoon/early evening thunderstorms, especially
for western areas. Most likely all thunderstorms Saturday will be
more isolated. Scattered thunderstorms are more likely Sunday,
Monday, and Tuesday afternoons where red flags, especially for
mountain zones, will likely be needed. Winds will pick back up
late Tuesday and Wednesday as a trough looks to move through the
area late Tuesday into Wednesday. Wednesday afternoon look for dry
conditions and gusty winds across mainly our northern areas,
including fire zones 410, 422, 475, and 476.
Wyatt
&&
.AIR QUALITY...Regional wildfires continue to impact air quality
over Southeast Idaho. Increased wildfire smoke will begin to
settle back into the area today under high pressure and light
winds. We continue to carry patchy smoke in the forecast over ooks to move through the
area late Tuesday into Wednesday. Wednesday afternoon look for dry
conditions and gusty winds across mainly our northern areas,
including fire zones 410, 422, 475, and the next two days, during
which the Idaho DEQ is forecasting "Moderate" air quality.
Cropp/Moore
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon Friday to 9 PM MDT Saturday for
IDZ051>059-061-062-065-067-075.
&&
$$
Area Forecast Discussion
National Weather Service Pueblo CO
528 PM MDT Thu Aug 1 2024
.KEY MESSAGES...
- Isolated to widely scattered thunderstorms, a few strong to
severe, remain possible across the southeast plains through
this evening.
- There is an additional risk for at least isolated strong to
severe storms across the eastern plains on Friday.
- Warming trend continues this weekend into next week. Daily
showers and storms will continue over and near the mountains.
- Cooler, unsettled pattern possible near the end of next week.
&&
.SHORT TERM /THROUGH FRIDAY/...
Issued at 247 PM MDT Thu Aug 1 2024
Still continue to monitor the risk for strong to severe storms
this afternoon, though latest radar imagery is showing rather
limited development this afternoon. This is likely due to
overall lacking large scale support, lack of strong focus at the
surface at this time, along with likely strong capping still in
place this afternoon. Despite these limiting factors this
afternoon, still think there will at least be isolated to widely
scattered shower and thunderstorm development through the
evening time frame. Increases in moisture with surface dew
points in the upper 50s to low 60s are in place across the
southeast plains, with even some upper 60s noted around the Baca
county area. This moist advection aided by strong low level
easterlies is helping with increased instability at this time,
with latest RAP analysis showing anywhere from around 1000 j/kg
to 2000 j/kg in place across the plains, mainly along and south
of Highway 50. So given these trends and with the higher
likelihood for some additional focus at the surface, think the
highest chances for storm development including the risk for
strong to severe storms will be along and south of Highway 50.
Additionally, easterly surface winds and veering profile are
supporting bulk shear values of 25 to 35 kt. So, if a more
robust updraft can get going, think the risk of wind gusts to 60
mph and hail to the size of ping pongs will continue over the
southeast plains through this evening.
No real big change to the larger pattern, with upper ridging
the trend on Friday and with above normal temperatures
persisting. The westward push of moisture and instability
continues on Friday, with expanding chances for showers and
thunderstorms. This will include the higher terrain during the
day, with chances increasing across the plains later in the day
into the evening. Confidence with the extent of the instability
axis is low at this time, though it is possible that a moderate
instability axis will be in place across the eastern plains.
This would support the risk of severe storms in this area even
despite more modest shear values. Even if instability is lower,
still think there is a risk for stronger development with gusty
winds, small hail, and heavy downpours the main hazards.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Issued at 247 PM MDT Thu Aug 1 2024
High pressure will continue to dominate overhead as we move
into this weekend and early next week. Modest north-northwest
flow will set in aloft this weekend, with some weak easterlies
at the surface over the plains. As a result, what moisture there
is, and subsequent storm coverage, will mostly be limited to
areas along the Continental Divide. Model guidance currently
shows Sunday having a better chance for more coverage compared
to Saturday, potentially due to a disturbance to the pattern
aloft passing by to our north. Meanwhile, temperatures will
continue to be above average, with 90s across the plains and
mid-high 80s for the high valleys.
Monday Onwards...
Models show the upper high remaining mostly in place over the
Rockies as we move through next week. High temperatures will
continue near or above seasonal averages, with some places over
the plains nearing or exceeding 100 degrees, mainly Monday-
Tuesday. Daily showers and thunderstorms will continue over and
near the mountains, increasing in coverage as several
disturbances travel through the flow aloft. A cooler, more
unsettled pattern will move in around the end of the week, with
models resolving a cold front moving in across the plains as the
upper high shifts more to the south and east. High temperatures
will noticeably decrease as more moisture moves into the area.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 523 PM MDT Thu Aug 1 2024
VFR conditions anticipated across much of the forecast area over
the next 24 hours, including the three main TAF sites of KCOS,
KPUB and KALS. Much of the ongoing convection this afternoon is
across the southern portions of the area, producing some gusty
outflow for KALS through 03z. However, hi-res models are
indicating potential for an isolated storm nearing the KCOS
terminal so kept mention of VCTS there from 03z to 06z. Less of
a chance for KPUB, and with such low confidence removed PROB30
wording there. Finally, FU continued for KCOS and KPUB until
around 03z this evening, then dissipating afterwards.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...RODRIGUEZ
LONG TERM...GARBEROGLIO
AVIATION...MOORE
Area Forecast Discussion
National Weather Service Reno NV
119 PM PDT Thu Aug 1 2024
.SYNOPSIS...
* Above average temperatures will continue through the weekend
into next week.
* Smoke from nearby wildfires will continue to impact portions of
northeast CA and western NV through the weekend.
* Increasing thunderstorm chances Friday through the weekend.
&&
.DISCUSSION...
Smoke: Smoke from the Park Fire will continue to blanket western NV
and northeast CA today through tomorrow morning. The latest HRRR run
has the smoke getting pushed up north Friday afternoon with a slight
southerly flow. So we`ll be able to have some relief on Friday and
most likely Saturday too. For a very good way to view the AQI in
your area we recommend going to fire.airnow.gov.
Temperatures: Lower NV valleys will once again crack the 100 degree
mark this afternoon! Temperatures will stay a few degrees above
average through this weekend and into next week.
Thunderstorms: A stream of moisture from the south combined with a
little instability will create a 40-60% chance for thunderstorms
Friday through Saturday. Storms will start off over Mono County
Friday afternoon and work their way north into northeast CA by late
Friday night. There is a 40% chance of nocturnal thunderstorms in
far western NV and northeast CA. Based on current soundings, these
storms will be fast moving and will likely have lightning, but also
have the high potential for localized heavy rain. Current QPF ranges
from 0.10-0.30", so nothing terribly heavy but if storms start to
train there could be a flash flood threat.
Extended Outlook: The weather starts to quiet down again after
Saturday. Sunday and Monday there is a 15% chance of showers in the
afternoon across western NV, although more fine tuned details will
come in the next few days. Then we start to dry out after Monday and
a high pressure system works its way back overhead.
-Justin
&&
.AVIATION...
We`re going to see lingering smoke and haze at most terminals the
remainder of today and through tomorrow morning from the Park Fire
in northern California. There will be periods of VIS 3-6SM and CIGs
BKN030-040 in the evening and overnight hours. There will be a
slight wind shift Friday afternoon out of the south that will push
the smoke and haze north of the region. Even KSVE will get some
relief from the smoke Friday evening onward.
Starting Friday afternoon through Saturday morning, there`s a 40-60%
chance for thunderstorms across far western NV and the Sierra.
They`ll start off near KMMH and the migrate north throughout the
evening. It will also be heating up again today and this weekend
with temperatures approaching 100 degrees lower valleys and 90
degrees in the Sierra which may result in some density altitude
impacts.
-Justin
&&
.FIRE WEATHER...
* More heat and low humidity will persist today with another round
of poor recoveries tonight as a dry airmass remains over the
Sierra and western NV.
* Moisture then increases from the south Friday with the risk of
thunderstorms increasing. Storms will begin as early as late
Friday morning around Mammoth Lakes/White Mts and spread
northward to the Tahoe Basin/Sierra Front by late afternoon.
PWATs will be increasing rapidly to around 1" with these storms
rooted in the boundary layer. Thus storms will be capable of
heavy rainfall, especially if cells anchor on the terrain or
train over the same areas. At the same time, storm motions will
be relatively quick. So a hybrid storm environment will exist
with the potential for new starts outside heavier rain
locations.
* As the wave lifts northward going into Friday night/early
Saturday, storms become more elevated as they continue to move
fast from south to north. Storms may be ongoing across the
Sierra and western NV as the sun sets Friday with uncertainty in
location and timing of upper level forcing going into the
overnight hours. We have maintained a 10-20% chance of lightning
overnight, but this bears watching as any additional increase in
lift would result in greater coverage, especially from the Tahoe
Basin and Sierra Front northward to the Oregon border.
Hohmann/Justin
&&
.REV Watches/Warnings/Advisories...
NV...Dense Smoke Advisory until 5 PM PDT this afternoon NVZ003>005.
CA...Dense Smoke Advisory until 5 PM PDT this afternoon CAZ071.
&&
$$
Area Forecast Discussion
National Weather Service San Diego CA
904 PM PDT Thu Aug 1 2024
.SYNOPSIS...
Chances of showers and thunderstorms continue over the mountains
and High Desert Friday afternoon. Chances of showers and
thunderstorms decrease over the weekend through Monday, increasing
again around the middle of next week. Hot conditions are expected
for inland areas this weekend into early next week. Marine layer
low clouds are expected to be thin and patchy into early next
week.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
It was an active afternoon and early evening for San Diego County. A
few severe thunderstorms warnings were issued in addition to two
flash flood warnings. Most of the thunderstorms developed in the
mountains and deserts of southeastern San Diego County but a few
light showers reached portions of the coast. A rainfall summary has
been headlined on our weather.gov/sandiego homepage but most of the
cells producing heavy rain missed rain gauges. Thunderstorms
produced 1350 lightning strikes (cloud to ground + cloud to cloud) in
San Diego county this afternoon and evening. Additional chances
of showers and thunderstorms are in the forecast for Friday
afternoon and early evening. Thunderstorm activity is expected in
the mountains and into the High Desert. Latest guidance from the
HRRR is showing the potential for locally heavy rain in the
mountains that could result in flash flooding. Otherwise, main
threats will be gusty winds near storms and frequent lightning.
From previous discussion issued at 2 PM Aug 1, 2024...
.SHORT TERM (Through the Weekend)...
Monsoonal moisture will remain in place, but in more normal SoCal
fashion with southeast flow in place and small chances across the
mountains and adjacent deserts. As the ridge of high pressure over
Texas moves westward toward the Four Corners region, warmer
temperatures will felt across the area. By Friday, temperatures will
be about 5 degrees warmer than they are today for many. Temperatures
will slowly increase this weekend with a drier atmosphere in place
per latest PWAT ensemble guidance. Central portions have a 50-70%
chance of seeing highs of at least 105 degrees by this
weekend.Saturday looks to be the driest day overall. Mountain
chances for storms look minimal (10-15%) each afternoon by this
weekend. The marine layer will keep the coastal areas cooler with
low clouds and patchy morning fog, but highs quickly increasing away
from the coast is also expected.
&&
.LONG TERM (Next Monday and Beyond)...
The high will flatten out a bit with even higher heights by early
next Monday and Tuesday as 850 mb temps reach near 31-32C. This is
when the peak of the heating is expected over SoCal. By Monday,
inland valleys, mountains, and deserts can expect temperatures up to
10 degrees above normal. NBM projects near a 70% chance of seeing
temperatures over 115 in Palm Springs Sunday through Tuesday. For
the Inland Empire, temperatures above 105 have about 20-40% chance
of occurring for areas near Riverside by early next week. Most areas
will stay in the 70s near the coast, quickly rising into the 80s
five miles or so inland by early next week.
Per latest model ensembles, the ridge will slowly break down
starting around next Wednesday into the latter part of next week.
This will decrease chances of rain over the mountains and bring not
as hot and humid conditions elsewhere.
&&
.AVIATION...
020330Z...SCT locally BKN clouds at or above 10000 feet MSL through
Friday.
Mountains/Deserts...CB clouds forming over mountain ranges and high
desert with isolated-scattered thunderstorms after 18Z Friday. Bases
would be around 10000 feet MSL with tops as high as 40000 feet.
Erratic wind gusts 30-40 knots possible near any thunderstorm.
Coast...Patchy low clouds expected after 09Z, but low confidence of
CIGS at coastal airports. If any, they would be based at around 800
feet MSL and of brief duration between 10-15Z.
&&
.MARINE...
No hazardous marine conditions are expected through Tuesday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning from 10 AM Saturday to 11 PM PDT Monday
for Coachella Valley-San Diego County Deserts-San Gorgonio
Pass Near Banning.
PZ...None.
&&
$$
PUBLIC...CO/APR
AVIATION/MARINE...MM
Area Forecast Discussion
National Weather Service Tulsa OK
911 PM CDT Thu Aug 1 2024
...New SHORT TERM...
.SHORT TERM...
(The rest of tonight)
Issued at 911 PM CDT Thu Aug 1 2024
The much advertised weak front currently extends across northeast
Oklahoma, roughly along Highway 412, and east-southeastward across
northwest Arkansas. Notable pooling of low level moisture has
occurred near the boundary, which is contributing to locally high
MUCAPE extending across the northern third of the forecast area.
The main concern overnight is how much thunderstorm development
will occur in response to the boundary and how robust it will be.
The HRRR has been consistent in showing scattered development
beginning to our west late this evening and spreading toward the
region after midnight, with more isolated development near the
boundary in far northeast Oklahoma into northwest Arkansas. The
00Z NAM indicates similar. Radar observations show an attempt at
this development to our west, with a lone, short- lived storm near
Enid in the past hour. The expectation given the above is that
attempts at isolated to scattered thunderstorms will exist
overnight in the vicinity of the boundary, which has been well
handled by the going forecast. The only change to the POPs tonight
was to increase them earlier in the evening, given the
aforementioned thunderstorm near Enid. Sky cover has been adjusted
upward through daybreak by blending the latest short-term blend
into the existing forecast. Other elements appear on track and
only updated for near term trends. Updated products already out.
&&
.LONG TERM...
(Tomorrow through Thursday)
Issued at 251 PM CDT Thu Aug 1 2024
Aforementioned front will continue to track south across the CWA
tomorrow, exiting SE OK in the afternoon. Some showers and isolated
storms may develop along the boundary again during the morning/
afternoon (SE OK), but overall potential remains low and CAMs remain
fairly pessimistic at this time. Additionally, any heat concerns
tomorrow will likely be restricted to SE OK as the rest of the
area is expected to remain below advisory thresholds in the post-
frontal airmass. Thus, have issued a Heat Advisory just for
Choctaw and Pushmataha counties where heat indices may climb
between 105-110 degrees.
Upper level ridge shifts westward for the weekend with N/NW flow
aloft. A shortwave embedded in the flow is forecast to slide into
W OK Saturday night/ Sunday. However, it still appears that our FA
will remain dry with few impacts from this feature other than
perhaps an increase in clouds. Otherwise, the main theme for this
weekend will be `slightly` cooler temperatures (highs still in the
mid-upper 90s) with light easterly winds.
Ridging expands overhead yet again early next week with southerly
sfc flow resuming. This will allow temps and moisture to increase
with potential for dangerous heat returning as we approach mid
week. Another frontal boundary attempts to push into our area
mid-late week but model guidance remains unclear just how far
south this feature will progress. With elevated heat indices
looking increasingly likely next week, anything to help cool
things off would certainly be welcome. Additionally, opted to
hold PoPs below mentionable values for this period given high
uncertainty at this range.
&&
.AVIATION...
(00Z TAFS)
Issued at 625 PM CDT Thu Aug 1 2024
VFR conditions are expected to prevail through the period for all
sites. A weak boundary moving into the region will bring low
chances (<30%) for thunderstorms across NE OK and NW AR tonight.
Chances remain too low for impacts to any one TAF site so have
left out of mention for now. Otherwise, light and variable winds
will shift more northerly during the morning tomorrow, but
generally remain less than 15 knots through the period. A
combination of dust and smoke has also caused some slight VSBY
reductions this afternoon, but should maintain VFR conditions
through the rest of the afternoon.
Bowlan
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 98 71 97 / 30 0 0 0
FSM 79 100 74 98 / 20 10 0 0
MLC 78 100 71 97 / 20 20 0 0
BVO 72 97 66 97 / 20 0 0 0
FYV 73 95 68 94 / 30 0 0 0
BYV 72 93 68 92 / 20 0 0 0
MKO 77 98 70 96 / 30 0 0 0
MIO 71 94 67 94 / 20 0 0 0
F10 77 99 69 97 / 20 20 0 0
HHW 77 102 73 99 / 10 10 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory from noon to 9 PM CDT Friday for OKZ049-053.
AR...None.
&&
$$
SHORT TERM...22
LONG TERM....43
AVIATION...04