Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/13/22
Area Forecast Discussion
National Weather Service Cheyenne WY
346 PM MDT Tue Jul 12 2022
.SHORT TERM...(This evening through Thursday night)
Issued at 207 PM MDT Tue Jul 12 2022
A much warmer day has set up across the region today due to an
upper level ridge amplifying across the Intermountain West. At the
surface, observed afternoon temperatures have ranged from the low
80s to middle 90s for most of the cwa as of 21Z. A dryline has
slowly been pushing east from the Laramie Valley toward the
Laramie Range. Dew points in the 40s and 50s were observed east of
the dryline, with dew points down into the upper teens to middle
20s. This has resulted in RH`s tanking behind the dryline for
areas in Albany and Carbon County...on the order of the upper
single digits to middle teens. MSAS analysis depicts a large
swath of 0-3km lapse rates ranging from 9 to 10.5 degrees C/km
across our cwa. Due to the strong heating, moisture presence,
steep lapse rates, and forcing from the converging airmass
boundaries along the dryline, diurnal convection has begun to
occur.
As the afternoon presses on, we will have multiple convective cell
initiations occur due to converging outflow boundaries. A Marginal
risk for severe wx has been produced from the SPC for today.
The location includes a line from the Northern Laramie Range
toward the southeast near Alliance to the south into Northern
Colorado. Primary hazards include strong, gusty outflow winds
upwards of 60+mph in the strongest of the thunderstorms, with an
isolated large hail up to an inch in diameter. The other hazard
that we will have to contend with is the high cloud bases that
will exist during the rain shower activity. This will create not
only virga rain showers and the potential for strong microbursts,
but perhaps an isolated dry thunder lightning strike to the west
of the main convection. HRRR and NamNest CAMs have the convection
initializing through this evening, with converging outflow
boundaries being the main proponent of new localized forcing, and
subsequent updrafts for new convection. Convection is progged to
exist through the late evening for SE WY, with isolated convection
lasting through 10-12Z in the NE Panhandle due to the localized
outflow boundaries.
Wednesday and Thursday will bring even warmer temperatures to the
region. The upper level ridge axis will shift to the east,
resulting in WAA across the area. Daytime highs will range from
the upper 80s to lower 100s for a majority of the High Plains that
do not reside in the higher terrain. Mountain zones will likely
see highs in the upper 60s to middle 70s, closest to the highest
peaks. With another push of monsoon moisture taking its time to
arrive, we will see the chances for weak thundershowers near and
after 0Z on Wednesday afternoon and evening. Isolated dry thunder
may be possible, but have left it out of the the FWF discussion
at this time. RH mins will range from 15-25%. Have also decided
against any fire weather headlines at this time due to weak
steering flow aloft that would be mixing down to the surface
during Wednesday and Thursday afternoons. Wind gusts at the
surface should stay below 25mph based off current model guidance,
but it will be close. Thursday evening will see a dramatic
increase in PWATs from 0Z-12Z(Friday) near 1-1.25 inches. This
should result in localized heavier rain showers for the region,
which will assist with areas currently experiencing drought
conditions.
&&
.LONG TERM...(Friday through Tuesday)
Issued at 207 PM MDT Tue Jul 12 2022
Chances for precipitation continue Friday afternoon extending into
the weekend. 500mb ridging pattern centered over the four corners
region will remain with multiple shortwaves passing overtop of the
ridge across the area. PWs east of the Laramie Range around 0.8-1.2"
will remain through the extended, which is above average, but still
pretty typical this time of the year during active patterns.
Convection will mainly be tied to the higher terrain initially,
before moving off onto the adjacent plains most days.
In addition to daily chances for precipitation, an extended period
of above normal temperatures will continue across the region. Area
of highest 700mb temperature around 18-20C will be centered over the
CWA by the end of the weekend. Warmest day of the long term period
looks to be Monday with much of the Nebraska Panhandle reaching the
triple digits. While Monday afternoon`s forecast temperatures
currently remain a couple degrees below record highs, Monday morning
forecast lows are in the upper 60s and low 70s. This is approaching
highest low temperature records. Will need to monitor this extended
period of hot weather (day & night) across the region as Heat
Advisories may need to be considered.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1125 AM MDT Tue Jul 12 2022
VFR conditions expected for area terminals through the forecast
period. SKC continue late this morning over the area, but isolated
thunderstorms may develop into this afternoon. Storms will mostly
likely form near KCYS around 20-21z, so decided to keep VCTS in
the TAFs into this afternoon before 00z. Storms will continue to
move east late this afternoon into early evening in the Nebraska
Panhandle approaching KSNY and KBFF. Main hazard will be gusty
outflow winds in the vicinity of any showers and storms.
&&
.FIRE WEATHER...
Issued at 207 PM MDT Tue Jul 12 2022
Fire weather concerns will range from low to elevated across the
FWZs as dry air moves from west to east this afternoon. A weak
disturbance will move across the area causing high cloud based rain
showers and thunderstorms. Min RHs west of the Laramie Range will
range from 10-18%, and east of the Laramie Range from 18-30% today.
Southerly winds of 5-15mph will transition to a westerly direction
of 10-20mph by late afternoon. Gusty and erratic winds of 25-35mph
or more are possible where rain showers and thunderstorms occur.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...BW
LONG TERM...MB
AVIATION...MB
FIRE WEATHER...BW
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
617 PM CDT Tue Jul 12 2022
...AVIATION UPDATE...
.DISCUSSION...(This evening through Tuesday)
Issued at 341 PM CDT Tue Jul 12 2022
So far today is a pretty typical summer day. Water vapor imagery
shows us in northwest flow aloft with the main ridge axis to the
west over the Rockies. With high pressure at the sfc winds are
fairly light and variable and will continue to be until later
tonight when the sfc high moves off to the east and we fall into
southerly return flow. While there is a chance we stay dry through
tonight, there is also the chance for some sprinkles and maybe even
a couple thunderstorms to pop up mainly after midnight and for areas
to the far west. This would be primarily driven by lift from the LLJ
just to our west edging into our area along with some decent WAA.
Morning runs of the HRRR, the RAP, and the NAMNEST all hinted at the
potential for some "sunrise surprise" activity, though later runs of
the HRRR have backed off this potential somewhat. Nothing severe is
expected.
Should anything develop tonight, it could linger into the mid-
morning hours, otherwise we should be dry through the day. Expect
warmer highs tomorrow in the 90s as the ridge axis pushes east and
becomes more centered over the Plains. In the evening, a small
perturbation moves through the ridge and could help set off an MCS
just to the west of the CWA. This could possibly clip our western
areas as it moves southeast and passes through north central
Kansas as it dies off. However, as mentioned in the previous
forecast, model consensus is still not great. Runs of the HRRR are
flip flopping as to whether or not we get clipped by what little
precip it develops. Whereas both the 12Z and 18Z runs of the
NAMNEST fully develops the MCS near our west and clips us. Due to
the lack of confidence and model consensus, have kept PoPs to just
20% and below for right now, but felt it was warranted to have at
least something in there.
Heat is the main concern for the extended. Expect hot
temperatures in the upper 90s and even some triple digits Thursday
and Friday, but especially Friday. Friday we could be pushing
Heat Advisory Criteria with heat indices as high as 107 in a few
places. Breezy southerly winds will help the feel of the heat a
little on Thursday, but no such luck on Friday. We do however get
a brief break from the oppressive heat over the weekend with highs
just a touch cooler but still in the 90s. Isolated storm chances
are also possible across portions of the area Thursday through
Saturday evenings and nights. Then the ridge axis shifts back east
over the Plains again and the bringing back the heat dome
possibly for several days. Several long range models are
indicating anomalously hot weather through nearly the end of July.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 611 PM CDT Tue Jul 12 2022
SFC high pressure will keep light winds over the TAF sites
overnight. The SFC high will move ESE overnight which will bring
southerly winds tomorrow morning. The gradient will tighten
tomorrow and expect afternoon winds in the 10-15kts range. VFR is
expected through the period.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Shawkey
AVIATION...Beda
Area Forecast Discussion
National Weather Service Goodland KS
453 PM MDT Tue Jul 12 2022
.SHORT TERM...(This evening through Wednesday)
Issued at 219 PM MDT Tue Jul 12 2022
19z Water Vapor indicated CWA on eastern fringe of 594 dm H5 ridge
centered over the 4 corners region. RAP dynamic tropopause analysis
indicated embedded short wave trough centered over the GLD area
and was slowly moving east south-east out of the area. At the
surface, trough was developing across eastern Colorado with 1019mb
high centered near KEAR. Visible satellite was showing area of
cumulus developing in area of return flow in northeast Colorado.
Main forecast concerns will center around small precip chances
through tomorrow afternoon, followed by magnitude of the warmup and
associated hazards on Tuesday.
Tonight...With previously mentioned short wave trough departing the
area, large scale forcing for ascent will quickly diminish. That may
limit initation of thunderstorms over the CWA, but overall
subsidence likely not strong enough to inhibit thunderstorms from
rolling off the higher terrain during the evening. Given the
position of the available instability axis, do not think storms will
be able to advance past the KS/CO state line. Considerable
uncertainty exists with respect to increasing LLJ allowing storms to
continue past 06z and am currently think it is unlikely that storms
will continue into the overnight hours, at least in an organized
sense.
Wednesday-Wednesday Night. H5 ridge will move east through the
period, with region getting closer to center/more removed from
influence of passing disturbances. While large scale forcing will be
missing, current forecast soundings and convective temperatures
suggest heating will be sufficient to erode convective inhibition.
Lack of a focusing mechanism leads me to think coverage will be
spotty and storms strongly tied to the diurnal heating cycle.
Otherwise expect to see temperatures several degrees warmer than
today with upper 90s and low 100s becoming established. Dewpoints
will likely drop to the 40s across western zones by late afternoon,
forcing humidities into the 15-20 percent range. However winds will
generally be lighter in this area and am not anticipating need for
any fire highlights.
.LONG TERM...(Thursday through Tuesday)
Issued at 144 PM MDT Tue Jul 12 2022
Early in the long term, the ridge axis shifts eastward and
amplifies, resulting in near-record high temperatures and near-heat
advisory criteria in northeastern portions of the area to close out
the work week. RH values in the mid teens on Thursday have potential
for increased fire weather concerns mainly along and west of KS Hwy
27, though winds are only expected to be in the mid teens to low 20s
(knots). Embedded disturbances within the ridge allow
afternoon/evening thunderstorm chances to remain in the forecast
Thursday through Saturday. The main threat with any storms continues
to be strong, damaging winds with inverted v profile forecast
soundings. Temperatures will be in the upper 90s to low 100s over
the weekend before the ridge amplifies again, bringing drier
conditions Sunday onward. Another day to monitor for fire weather
conditions will be Monday as RH values drop into the teens and
forecast wind gusts are in the upper teens to low 20s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 452 PM MDT Tue Jul 12 2022
For KGLD & KMCK... VFR conditions are expected through the TAF
period. Winds will remain roughly from the south through the
period around 10-12 kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...CC
AVIATION...KAK
Area Forecast Discussion
National Weather Service Gray ME
1121 PM EDT Tue Jul 12 2022
.SYNOPSIS...
Scattered showers diminish after midnight. An upper level
trough will approach from the west Wednesday, bringing another
chance for showers and possibly a thunderstorm, mainly in the
north. High pressure moves in for the end of the work week, with
conditions expected to remain mainly dry. Unsettled conditions
then move in for early next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
11:20PM Update...
Quick update to fit lowering POP trends with the remaining
showers across the area. Some scattered showers remain possible
across northern areas for the next few hours, while the showers
across central Maine continue to diminish. Some patchy fog is
starting to develop in spots, and this trend should continue
overnight.
9:10PM Update...
The severe storms have moved through the area, with scattered
showers and thunderstorms lingering across northern areas and
parts of the Seacoast. These will continue to gradually
dissipate over the next few hours, with clearing skies expected
after midnight. With the recent rainfall, areas of fog are still
expected later tonight, but otherwise a mild summer night is
expected.
Previous...
Thunderstorm activity has moved into western NH at this hour,
with strong winds reported at KLEB. With this development, a
Severe Thunderstorm Watch has been issued for New Hampshire as
well as the mountains and foothills of Maine until 9pm.
This activity has been well advertised by NAMnest runs today,
and have adapted much of the forecast timing to this. So far
storm mode has been more cellular vs linear, which the HRRR
handled well. Clear skies and warm temps to the east will keep
these storms sustained for much of its transit towards the
coast. With some of the marine air being displaced northward
along the Midcoast, thinking is this stable air will inhibit
storm development here. Thus, greatest threat for svr reaching
the coast should be confined to the NH and southern Maine coast.
Cannot rule out some rumbles of thunder to the north through mid
evening.
To the north along the Int Border and mountains, shower and
thunderstorm activity is filling in. This area is also pose some
strong to severe chances, but also a training heavy rain threat.
Vectors seem to support this, especially amid some remaining
moisture.
Convective activity should end by late this evening, with the
chance of some patchy fog along the Midcoast. Otherwise, winds
become lighter.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Some scattered showers will be possible, mainly in the mountains
and interior Wednesday. Have trimmed thunder chances given the
shallow layer of moisture avail. These should be diurnally
driven, and taper later in the evening. Otherwise, a partly
cloudy day, again warm along the coastal plain up to the
foothills.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Overview... A longwave trough passes overhead during the second half
of the week before high pressure sets in for the weekend. This
brings a chance of light showers Thursday morning before
clearing up overnight. A shortwave trough then swings through
Sunday bringing another chance of showers Sunday night with
lingering unsettled conditions through the end of the extended
period.
Impacts: No significant weather related impacts are currently
expected during the long term portion of the forecast. High
astronomical tides through Saturday may result in some splashover
and minor coastal flooding around high tide each day.
Details... Light showers start off the day Thursday morning as weak
low pressure passes to the south. These showers will be light with
most areas seeing less than a quarter inch of rain throughout the
day. High pressure starts moving in Friday clearing up showers
overnight, however there may still be some lingering showers in the
mountains Friday morning. A warming trend sets in over the weekend
under high pressure with highs starting in the 80s Friday, climbing
into the high 80s and low 90s for southern areas by Monday. A
shortwave trough swings through bringing another chance of showers
late Sunday with unsettled conditions lingering through early next
week. Ensemble guidance shows these showers remaining light with
low QPF for little drought relief. Through the entire long term
period, ensemble guidance only shows a 30 percent chance, at most,
of greater than half an inch of precipitation in 24 hours. Most
guidance only shows a total of half an inch to an inch of total
precipitation throughout the long term period. Even with a few
shortwaves and unsettled conditions, the moisture and forcing is
lacking for any widespread wetting rain to replenish groundwater
supplies. A cluster of shortwave troughs could swing down from
Canada by midweek bringing low pressure to the area, however weak
zonal flow aloft keeps the track and intensity of these shortwaves
rather uncertain at this time.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Some BR will be possible along the Midcoast around
KRKD and KAUG. VFR expected Wednesday and Wed night.
Long Term... Primarily VFR conditions are expected through the
extended period with -SHRA Thursday and unsettled conditions Sunday
through the end of the extended period. These showers will be
light with brief periods of MVFR.
&&
.MARINE...
Short Term...SCA continues tonight, with winds slackening below
levels this evening. Waves will be slower to lower, but decrease
below SCA criteria Wed morning. Patchy fog may develop over the
waters tonight.
Long Term... High pressure will settle over the waters Friday
into Saturday, allowing for an extended period of light winds
and fair seas through the extended period. Light showers will be
possible Thursday and early next week.
&&
.TIDES/COASTAL FLOODING...
High astronomical tides will continue this week. Some water may
reach minor flood levels surrounding time of high tide. A
Coastal Flood Advisory was issued for tonight`s high tide in
combination with some southerly onshore flow.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Coastal Flood Advisory until 1 AM EDT Wednesday for MEZ023>028.
NH...Coastal Flood Advisory until 1 AM EDT Wednesday for NHZ014.
MARINE...Small Craft Advisory until 7 AM EDT Wednesday for ANZ150>154.
&&
$$
SYNOPSIS...
NEAR TERM...Clair
SHORT TERM...Cornwell
LONG TERM...Thunberg
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Marquette MI
1150 PM EDT Tue Jul 12 2022
.SHORT TERM...(This evening)
Issued at 311 PM EDT TUE JUL 12 2022
Headlines:
-Lingering low clouds from last night and this morning, conditions
improving
-Severe threat for tonight is marginal and likely limited to the
MI/WI state line
The forecast remains dominated by shortwaves embedded in the western
flank of a broad upper-level trough over the eastern third of the US
and Canada. Remnant clouds and moisture from last night`s shortwave
and general upsloping northwestern flow have led to some lingering
low clouds and drizzle in the morning. For the early afternoon,
diurnal heating and mixing have decreased the low clouds and the
drizzle is gone.
This evening, a 500mb shortwave will pass along the MI/WI state
line, with most of the associated vorticity being forecast by the
12Z GFS to occur on the WI side. 15Z run of the RAP shows up to 1000
J/kg of SBCAPE along the state line, but sharply dropping off to the
east, likely due to the clearer skies enhancing diurnal heating in
Gogebic, Ontonagon and western Iron counties relative to the areas
immediately east. 20 kts of Bulk Effective shear by mesoanalysis
gives storms some shear to work with, but not impressive shear. Mid-
level moisture will be more than sufficient for convection, with
widespread 700mb RH values over 90%. Given the forcing is almost all
in WI and the lingering clouds in the central UP are limiting
surface heating, I would be surprised if there was any significant
storm presence in the Eastern Time Zone. Isolated damaging wind and
hail are the threats, though chances remain low and limited to the
western UP.
.LONG TERM...(Tonight through Tuesday)
Issued at 311 PM EDT TUE JUL 12 2022
Little change in the forecast through the week and into the weekend
as medium range models and their ensembles continue to show good
agreement in the overall pattern across NOAM. Broad troffing across
the Great Lakes region will transition to a building ridge from the
west on Tuesday night as sfc high pressure begins to move over the
Upper Great Lakes. This will favor a warming trend into the weekend
and the start of next week as the ridge is expected to persist.
There will be a few chances for precip through the weekend as
multiple ridge-running waves propagate through the Northern Plains.
Specifics for these convective complexes will need to wait as there
are some spatial and temporal differences among the models.
Sfc high pressure takes over as a ridge begins to build in from the
west on Wednesday, which should bring warming conditions with benign
weather to end the week. PWATs fall to near the climatological min
on Wednesday night with clear skies and light winds - would not be
surprised to see a few upper 30s for temps across the interior cold
spots. Otherwise some 40s to low 50s near the shores are expected.
SW return flow will begin on Thursday, which should bring more
widespread 80s for Friday into the weekend. Models begin to diverge
in the details Friday into the weekend as a wave rounds the top of
the western CONUS ridge, which could bring some showers and
thunderstorms across the UP. Right now, models suggest the first
complex to pass to our SW across southern MN and central Wisconsin
on Friday. The next chance would be Saturday evening/night. If the
first complex dives south of the UP, it will likely force the second
system to also take a more southern track as it remains along the
instability gradient to the south.
However the precipitation threat works out, models suggest a warmer
trend into the weekend, with humid conditions becoming likely by
Friday afternoon through the weekend with PWATs near 1.25 to 1.5
inches. Temperatures will likely hold in the 80s to near 90 through
the weekend; however, widespread 90s on Monday/Tuesday look possible
as a regime change brings strong WAA and a LLJ across the area to
start the week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1146 PM EDT TUE JUL 12 2022
LL stratus/FG has been settling into portions of Upper Michigan
tonight, particularly at KIWD. This trend is anticipated to
continue through the overnight hours at all three terminals of at
least some periods of reduced cats due to cigs, visbys, and/or
some combination thereof. The typical diurnally-driven
improvements will then follow, with skies clearing out later in
the day at the terminals. Light and variable winds overnight will
slightly pickup in speed during the Wed. daylight hours, wavering
around but generally remaining in the N to NE directions.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 311 PM EDT TUE JUL 12 2022
As weak thunderstorms cross the west half of Lake Superior this
afternoon/evening, it will bring some locally gusty winds and a
patchy dense fog threat through tonight. As surface high pressure
builds across the lake tonight through Thursday, light winds will
prevail. South to southeast winds will gust between 15 to 20 knots
on Friday afternoon into Saturday morning as the high pressure exits
to the east. Light southerly winds will then prevail through the
weekend as the Upper Great Lakes remain on the outskirts of a
persistent ridge across the Central Plains.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Dense Fog Advisory until 11 AM EDT /10 AM CDT/ Wednesday for
LSZ162.
Lake Michigan...
None.
&&
$$
SHORT TERM...GS
LONG TERM...JAW
AVIATION...lg
MARINE...JAW
Area Forecast Discussion
National Weather Service Paducah KY
556 PM CDT Tue Jul 12 2022
.UPDATE...
Issued at 555 PM CDT Tue Jul 12 2022
Updated Aviation discussion for the 00z TAF issuance.
&&
.SHORT TERM...(Tonight through Wednesday night)
Issued at 212 PM CDT Tue Jul 12 2022
Surface front was almost completely south of west KY early this
afternoon. Weak shallow light showers or sprinkles continue to
dissipate as drier air and extremely weak support work against the
activity. We anticipate convective chances should stay near or just
south of our area into AR and TN through the late afternoon and
evening hours. Having said that, some of the hires guidance shows
convective development in the vicinity of the MO Bootheel region and
across northeast AR tonight. We will monitor this potential for SEMO
and SW KY. For now we will leave the forecast dry. The HRRR seems to
be the only model guidance showing the potential. If it`s on to
something we do not want to completely discount it. The evening
shift can take another look.
As high pressure continues to take control in the wake of the cold
frontal passage, dry weather, along with seasonal temperatures and
humidity levels can be expected Wednesday through Wednesday night.
.LONG TERM...(Thursday through Tuesday)
Issued at 212 PM CDT Tue Jul 12 2022
The primary focus during the period will be chances for scattered
showers and storms this weekend into early next week. We begin the
period with above average confidence but then it quickly decreases
due to model variability over the weekend.
In the upper levels, a strong ridge will remain parked over the
southwest U.S. Meanwhile troughing will persist across the eastern
U.S. This places our area in northwest flow, allowing disturbances
to ride around the periphery of the ridge and dive south into the
lower Ohio Valley. Models are struggling with respect to timing and
placement of these weak shortwaves. The first one may arrive as
early as Friday night into Saturday, with the GFS continuing to be
the most robust with it. With lower confidence still, will maintain
just slight PoPs for now.
There is somewhat better agreement for a more pronounced wave to
ride southeastward into the area Saturday night into Sunday.
However, variability still exists hence why confidence is lower than
average.
Troughing remains in place across the TN Valley into early next
week, allowing scattered convection to continue in a moisture rich
environment. By Tuesday, ensemble guidance suggests upper level
heights may begin to rise as the ridge tries to expand its eastward
extent. If this happens then our convective chances should decrease.
Temperatures will be dependent on total sky cover and overall
coverage of pcpn for the weekend into early next week. For now the
initialized mid 80s to around 90 seem appropriate, before we begin to
heat up some by Tuesday. However, these numbers could be several
degrees too warm depending on the spatial extent of any convection.
Humidity levels start off below average with dewpoints in the
tolerable range Thursday and Friday (low to mid 60s). Thereafter,
they rise through the weekend with values back around 70 on Sunday
and into the lower half of the 70s Monday and Tuesday.
&&
.AVIATION...
Issued at 555 PM CDT Tue Jul 12 2022
VFR conditions are expected through the forecast period.
Lingering post-frontal cirrus clouds oriented along the Ohio River
will gradually diminish tonight. A few diurnal CU will develop
during the 18-24z period Wednesday, primarily around MVN, EVV,
and OWB. Winds will be N-NW around 5-7 kts.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...DWS
SHORT TERM...08
LONG TERM...SP
AVIATION...DWS
Area Forecast Discussion
National Weather Service Reno NV
249 PM PDT Tue Jul 12 2022
.SYNOPSIS...
Isolated thunderstorms are possible this afternoon into the
overnight hours, with the potential to produce gusty and erratic
winds and fire starts. We will see highs well above 100 degrees for
the lower valleys of western Nevada today, and slightly above
average temperatures for the remainder of the week. The potential
for thunderstorms along the eastern Sierra and far western Nevada
returns this weekend.
&&
.SHORT TERM (through Wednesday Night)...
Isolated thunderstorms are possible this afternoon into the
overnight hours. Short- term model guidance continues to change,
leading to some uncertainty in the timing and location of these
storms. However, we are seeing some cumulus buildups this
afternoon over Mono and southern Lyon counties, indicating current
HRRR guidance is under the realm of possibility. HRRR composite
reflectivity shows isolated showers and thunderstorms initiating
late this afternoon over Mono, Mineral, and southern Lyon counties
due to convection from intense surface heating. These storms are
expected to continue tracking north- northeast through the
afternoon, reaching the US-50 corridor and continuing on towards
Fernley, Pyramid Lake, and Pershing County through the evening.
After surface heating diminishes following sunset, a weak
disturbance may initiate a few isolated cells overnight.
Confidence on the exact placement of these overnight storms
remains low, as models are in disagreement with how far west they
will extend. HRRR composite reflectivity suggests a few cells
popping between Carson City and far northeastern California. On
the other hand, the NAM composite reflectivity keeps cells over
west central Nevada overnight. Regardless of this uncertainty, the
general takeaway is that any storms that develop tonight will be
isolated, fast moving, high- based cells tracking northward across
one or more of these areas.
Rainfall with today`s storms will be little to none, as model
soundings for locations across our region point to dry lower-levels
and a high-based LCL. The lack of measurable precipitation in
addition to the fast-moving nature of these storms raises a few fire
weather concerns, addressed in more detail below.
Satellite imagery shows smoke from the Washburn Fire creeping north-
northeast in a narrow plume towards the Tahoe Basin and far
western Nevada this afternoon. Expect a decline in air quality
through the afternoon in these areas. Afternoon westerly Zephyr
winds should mix smoke out along the Sierra front, but haze will
remain through the morning tomorrow. Southwest flow over our
region will continue pushing smoke over western NV and northeast
CA tomorrow, depending on continued fire activity.
-Whitlam
.LONG TERM (Thursday onward)...
* Typical mid-summer synoptic pattern into next week with the Four
Corners high in place coupled with troughiness off the west coast.
This yields southwesterly flow which a lot of the time is a dry
pattern, but simulations show enough moisture sneaking around the
western side of that high to produce t-storm possibilities
starting on Friday.
* Best odds for storms are over the Eastern Sierra and adjacent
parts of W Nevada south of Hwy 50 Friday through the weekend and
into early next week, with NBM t-storm POPs around 15-30% each
afternoon. Many of the ensembles bring enough moisture northward
to Reno-Tahoe and possibly even Lassen Co on Saturday to kick off
a few t-storms, with NBM showing about a 1 in 6 chance in the
thunderstorm POP guidance. Zephyr convergence will be key here in
how numerous storms get this far north. Similar numbers for Sunday
too but less certainty on having sufficient moisture, instability
then.
* Daily zephyr W/SW breezes are expected with temperatures near to
about 5 degrees above normal. A few spots in W Nevada will make a
run at 100 degrees especially Friday-Saturday, but definitely shy
of any records. Heat Risk levels peak out at orange/moderate for
most areas meaning those sensitive to heat or outdoors for
prolonged periods may need to take extra precautions. Some slight
cooling is projected by the NBM and ensembles for mid-late next
week, but nothing dramatic enough to result in increased
winds/fire weather threat.
-Chris
&&
.AVIATION...
* Trough off the west coast coupled with intense heating thermal
low over central and eastern Nevada will yield west/southwest
flow over the region into Wednesday. Smoke from the fire near
Yosemite as a result will have a better chance of impact
airfields east of the Sierra crest today and tonight and
possibly Wednesday. Based on the latest HRRR Smoke the highest
risk for sub-VFR conditions is between TVL-CXP southward to
Bridgeport and Hawthorne. Elsewhere a general haze with
visibilities 6-10 miles is expected. If the fire is active
enough we could see a dense smoke layer aloft around 10- 15kft
MSL this evening and tonight south of RNO to TVL/MEV that could
result in terrain obscuration.
* Sufficient moisture, though just barely, and instability from
heating will result in t-storms developing this afternoon and
early evening. 15-25% chance of storms impacting areas from
TRK- RNO southward into the Eastern Sierra including MMH
starting around 21z, moving E/NE into W Nevada after 3z. Brief
periods of MVFR are likely. Strong outflow winds above 40 knots
are feasible, and HRRR even showing some modeled storms
producing outflows above 50 knots. This could produce blowing
dust visibility reductions over W Nevada. Storm motions will be
to N/NE around 20-25 knots based on forecast soundings. Elevated
instability coupled with subtle shortwaves will keep 10-20%
chance for storms/lightning and erratic outflow winds going into
overnight hours and pre-dawn Wednesday morning. Storm motions
will be faster overnight, closer to 30-35 knots to the NE.
-Chris
&&
.FIRE WEATHER...
Thunderstorm potential this afternoon and overnight remains the
greatest concern. Confidence on lightning activity and varying
fuel moisture content still hinders the issuance of any watches or
warnings on this event.
Thunderstorms are expected to develop over Mono, southern Lyon,
and Mineral counties this afternoon. Later in the evening, it is
uncertain how far west these cells will develop. Generally,
coverage across western NV and far northeastern CA remains
isolated (10-15%) through the overnight hours.
Forecast soundings still note inverted-V atmospheric profiles with
dry low levels, high-based LCL, and moist upper levels. This
atmospheric profile is conducive to mainly dry storms with gusty,
erratic outflow winds. Confidence in lightning potential is still
low, though this does not look like a widespread dry lightning
event. The ECMWF lightning flash rate product currently suggests
some flashes along the eastern Sierra into the Sweetwater
Mountains. Due to the fast moving, generally dry nature of these
storms, any lightning strikes could lead to new fire starts.
Southwest flow will bring dry conditions and an enhanced Zephyr
wind Wednesday through Thursday, with afternoon gusts up to 35
mph. This pattern raises concerns for potential holdover fires
from any smoldering fuels from lightning strikes. -Whitlam
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php