Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/17/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
827 PM CDT Wed Aug 16 2023
.UPDATE...
Issued at 825 PM CDT Wed Aug 16 2023
Overall the forecast appears to be doing just fine. About the only
change was to add sky cover for the elevated smoke. Most of the
smoke should move south of the region by sunrise Thursday.
&&
.SHORT TERM...(This Evening through Thursday Night)
Issued at 322 PM CDT Wed Aug 16 2023
The cold front continues to make progress across the CWA, perhaps an
hour or so quicker than the HRRR had showed earlier today. Cooler
and drier air is filtering into the CWA as the front makes its way
through the eastern CWA. As we head into the overnight hours,
surface high pressure will be building in as winds slowly diminish.
Winds don`t go completely light though, so stuck fairly close to NBM
values and opted not to side with lower end percentiles.
The surface high will be right overhead on Thursday, keeping skies
mostly sunny with pleasant temperatures in place in the 70s to lower
80s. By Thursday night, the high shifts east and warm air advection
with southerly winds quickly ensues, signaling the quick warm up
anticipated for Friday.
.LONG TERM...(Friday through Wednesday)
Issued at 322 PM CDT Wed Aug 16 2023
The common theme through this portion of the forecast will be
building heat and humidity. Not much change in the overall guidance
trends from the deterministic and ensemble solutions compared to
their overnight runs. An upper ridge initially will be centered
across portions of the Southern Plains when this period begins on
Friday morning. The ridge axis will be positioned over parts of the
Northern Plains and Upper Midwest on Friday leading to a pretty hot
day CWA wide, but especially across portions of our Missouri Valley
zones where triple digit high temps look probable. Humidity levels
will be just high enough that when combined with these readings over
the century mark, heat indices approaching 105 degrees will be
possible. Friday could feel like a blast furnace so to speak as
we`ll see a tight pressure gradient set up across our area.
Southerly winds gusting up to or just over 40 mph will be possible.
Dry conditions look to not only persist on Friday but right on
through the weekend for most areas.
Guidance does track a cold frontal passage through the forecast area
on Saturday. It looks to have little moisture associated with it, so
expect the dry forecast to prevail. However, we can`t completely
rule out a stray shower or storm by late Saturday night or early
Sunday across north central SD as some mid level energy tries to
crash through the upper ridge. At this point though, better chances
for this to materialize across the western Dakotas and Northern High
Plains. Saturday should feature another hot day with widespread 90
degree temperatures and high humidity levels. A bit of a brief cool
down is possible for the end of the weekend as sfc high pressure
tries to nose in as northerly winds draw in some cooler readings in
the 80s to around 90 degrees. All indications are by early next
week, the upper ridge re-asserts itself and centers right across the
nation`s mid-section. This will mean more of the same for our area
as daytime temperatures look to warm and be back well into the 80s
and 90s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 610 PM CDT Wed Aug 16 2023
Terminals KABR,KATY,KPIR,KMBG
VFR skies/vsbys are expected overnight, along with decreasing
winds.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TDK
SHORT TERM...TMT
LONG TERM...Vipond
AVIATION...TDK
Area Forecast Discussion
National Weather Service La Crosse WI
1052 PM CDT Wed Aug 16 2023
.DISCUSSION...(Tonight through Wednesday)
Issued at 152 PM CDT Wed Aug 16 2023
Key Messages:
- Breezy conditions going into the evening, with a storm threat
from mid evening into the overnight
- Smoke possible Thursday and Friday
- Heat builds in starting this weekend
Tonight: Breezy with storm threat
As we start the latter half of August, a variety of weather to cover
even with fairly tranquil conditions expected into next week.
First focus is gradient winds and convective threat tonight as
deepening mid level wave moves across southern Canada and northern
Midwest/Great Lakes. Pressure falls continue to expand this
afternoon as boundary layer winds increase ahead of this wave.
Meanwhile associated cold front is also making good progress
southeast and was already into northwest Minnesota as of 18z.
Better moisture axis, and related MLCAPE, is along and ahead of
front in a fairly narrow corridor. This extends from northwest
Wisconsin to southwest Minnesota and could exceed 2000 J/kg with
peak heating this afternoon. Have been watching observations
compared to mesoscale models /like HRRR and RAP/ and a little
worried instability could be a bit stronger than models hint but
will continue to monitor trends. In any event, timing of front
suggests MLCAPE values decreasing as storms approach so a bit higher
risk for severe storms off to the west and north. Questions too
about coverage with main forcing of wave quite a ways north yet.
This might suggest northern counties, especially in Wisconsin, could
run a higher risk for stronger storms this evening. Storms should
remain tied to front and with stronger mid levels winds associated
with wave, storms could pose a gusty wind or hail threat. Expect
activity to weaken late evening on as front works south and east.
Thursday - Friday: Cooler with some atmospheric smoke
Once wave clears region and we return to a northwest flow, will need
to track advection of western wildfire smoke. Fairly decent signals
in HRRR/RAP runs of area of smoke settling into area later Thursday
and perhaps persisting into Friday. Most of it should remain aloft
but given subsidence behind wave, might see some lower level impact
and related air quality alerts.
Saturday into next week: Heat builds in with possible heat advisories
From the weekend on we will be watching the growth of large upper
ridge and heat dome over the central U.S. This has been persistent
in medium range ensembles and showing good consistency in cluster
means from Day 3 on. Strength and proximity of upper high suggest
we should remain capped with convective threats running mainly
north of us into next week before we see some retreating. Always
have to watch for convective features in these scenarios in case
passing wave flattens ridge a bit more than ensembles.
So how warm? Even disregarding the usual GFS extreme numbers, could
see some 27-29C 925mb temperatures on Sunday and perhaps next
Tuesday which normally would correlate to mid to upper 90s.
Anomalies in NAEFS still +2 to +3 deviations suggesting a hot
period but perhaps not record. There is a day early next week when
area record highs are a bit lower so could flirt with a few then.
At this point not seeing higher surface dewpoints that would push
further into excessive heat concerns, but could be bordering
advisory for a few days, especially from Sunday on.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1052 PM CDT Wed Aug 16 2023
A shower/storm may impact KLSE near the beginning of the TAF
period, but coverage this evening has been quite scattered, so
confidence in thunder is low (20%). Otherwise, winds will shift
NW and gust up to 25 kts on Thursday. A SCT/BKN cumulus field will
rotate across the region on Thursday, mostly VFR, but MVFR
conditions could not be ruled out briefly for a time on Thursday
morning. Winds will subside Thursday evening. Wildfire smoke is
expected to impact the area by later afternoon. Did introduce
smoke at KRST, but confidence in visibility is lower at this time.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Shea
AVIATION...JM
Area Forecast Discussion
National Weather Service Burlington VT
1015 PM EDT Wed Aug 16 2023
.SYNOPSIS...
Showers rotating eastward through parts of the region will
diminish tonight. Expect lingering patchy low clouds and fog
overnight with dry air aloft moving overhead. Warmer conditions
will follow with south winds tomorrow, especially west of the
Green Mountains. The next round of precipitation moves in
Friday, with some locally heavy rain possible. Dry and
seasonable weather returns for the weekend.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 1013 PM EDT Wednesday...A stubborn shower across Rutland
County is beginning to show signs of winding down on radar and
ground truth is reflecting this, however, with how persistent
the showers have been this evening, it is not a no-PoP kind of
night. Have blended in some of the high res models that are
depicting this shower to the forecast, resulting in some slight
chance PoPs running up Vermont throughout the night. Other than
that, the forecast is on track with minimal tweaks needed this
update. Previous discussion below:
Previous discussion...
For tomorrow, more of a seasonably warm day is expected in a
modest warm air advection pattern. South-southeast low level
wind will maintain low clouds through at least midday in central
and eastern Vermont such that high temperatures may be stunted
in the 60s to lower 70s for much of the day, with temperatures
ranging from the upper 70s to mid 80s farther west in the
region. Instability gradients will help produce pinprick
showers, with minimal instability during the daytime to generate
heavier rain. Unlike today, moisture will be rather shallow
limiting coverage of convection, and forecast soundings continue
to show a mid-level inversion that will put limit growth of any
convection that does get going.
The picture changes substantially tomorrow night, especially
towards midnight as upstream organized convection approaches
northern New York. Because convection will become elevated,
chances that strong winds mix to the surface are low but there
will be substantial low level shear and spin. NCAR probabilistic
convective hazard forecasts based on the HRRR shows severe wind
chances upwards of 10% within 40 km of a location in our far
southwestern areas during this period, supporting non-severe
wind gusts being the expectation at this time. The main impact
from this convection will be the strong forcing for rainfall as
a deepening, pre-frontal trough enters the eastern Great Lakes
overnight. The latest consensus has not changed much with
regards to a soaking rain with embedded thunderstorms moving
eastward through northern New York and perhaps Vermont by
daybreak. A quick half inch to an inch in many areas with
localized higher amounts are possible.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 312 PM EDT Wednesday...On Friday, a deep upper low with an
associated negative tilt trough will pivot across the area. Rain
should be ongoing, but is expected to maximize during the morning
towards about noon as the combination of favorable upper level
divergence and strong low-level convergence produce widespread
precipitation. We will be within the triple point of a sharp frontal
boundary. There will also have some instability on the order of 500
J/kg adding a convective element to precipitation. This should set
the stage for moderate to heavy rain, with PWATS about 125 to 150
percent of normal. Depending on the strength of the upper low and
associated southeast flow aloft and how a lee side trough over the
Appalachians develops, there could be a couple rounds of
precipitation involved before all is said and done.
During the afternoon, the upper low will shift overhead, and a dry
slot will move over the area, partially clearing the region, and
allowing temperatures to climb into the mid 70s. It will be in this
time frame, where we will observe 850 hPa winds increasing to about
30 knots, with some mixing taking place, which should produce some
20 to 30 mph gusts. As the upper low starts moving east, cold air
aloft will move into the area and result in some destabilization,
mainly across Vermont during the afternoon. Once east of Vermont,
some deformation on the backside appears to produce some showers
focused along northwest facing slopes of the Adirondacks and Greens.
Cloud cover and continued winds will keep temperatures from falling
too far, but with the cold advection starting, we should observe 50s
heading into Saturday morning. Between the overnight hours and
Friday night, precipitation totals should range between a third to
two thirds of an inch, with a strip of 1-1.25" depending on the
speed and intensity of the upper low affecting the heaviest rain
axis. At this time, the forecast has it situated along and between
the eastern slopes of the Adirondacks and Green Mountains.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 312 PM EDT Wednesday...The heaviest rain will move out by Saturday
morning as the cold front will exit the area Friday night.
However, there will still be a couple light showers during the
day, especially in the higher terrain. This is due to an upper
level low moving across the area. This low will move out for the
day on Sunday and ridging will move in. This will lead to a
drier and warmer day. Temperatures will rise into the 80s in the
Champlain and St. Lawrence Valleys and upper 70s outside these
valleys. Temperatures will increase more for Monday, but there
is uncertainty on how much they will rise. The ECMWF has
temperatures only a couple degrees higher than on Sunday, but
the GFS has temperatures almost 10 degrees higher, with highs
making a run at 90 in the valleys. A cold front will come
through Monday with the chance of a few showers. This will cool
temperatures back down to around seasonable levels for much of
the week and keep the ridge that is giving much of the country
sweltering heat at bay. So for now, largely stuck to blended
guidance for this portion of the forecast because of some timing
differences with the cold front.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...A mix of VFR and MVFR conditions continue
this afternoon/evening from lingering low level moisture
following showers. These showers should be tapering off as the
weather quiets into the night tonight, however, fog and low
stratus will be our next concern. Have prevailing IFR at KMPV
from 04Z-07Z Thursday, similar to what occurred last night, then
a tempo group of IFR conditions around 11Z-12Z Thursday for a
potential sunrise surprise of fog. For KSLK, went with a tempo
group 07Z-11Z Thursday of IFR as there is less certainty of
nonstop low vis/cigs at this site. At all other sites, VFR and
MVFR mix will continue off an on over the next 24 hours, largely
dependent on how pervasive cloud cover is. Overall, cloud layers
are expected to hang low, but whether few or overcast or
anything in between will determine VFR vs. MVFR. Have some 4SM
and low SCT clouds in at KMSS to indicate some fog could develop
there, but there is even lower confidence there than at KSLK.
Winds overnight will be largely light and variable becoming
gusty tomorrow out of the south/southeast with G15-20 knots at
some sites.
Outlook...
Thursday Night: Mainly VFR, with local IFR possible. Chance SHRA,
Slight chance TSRA.
Friday: Mainly VFR, with local IFR possible. Likely SHRA, Slight
chance TSRA.
Friday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Saturday: Mainly MVFR, with areas VFR possible. Slight chance
SHRA.
Saturday Night: Mainly VFR, with areas MVFR possible. Slight
chance SHRA.
Sunday: VFR. NO SIG WX.
Sunday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Monday: Mainly VFR, with local MVFR possible. Slight chance SHRA.
&&
.EQUIPMENT...
The Plattsburgh ASOS located at the Plattsburgh International
Airport will be down until further notice, as our ET`s await
the arrival of parts.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Kutikoff
NEAR TERM...Kutikoff/Storm
SHORT TERM...Haynes
LONG TERM...Myskowski
AVIATION...Storm
EQUIPMENT...WFO BTV
Area Forecast Discussion
National Weather Service Caribou ME
1205 AM EDT Thu Aug 17 2023
.SYNOPSIS...
Weak high pressure builds in through Thursday then exits across
the Maritimes Thursday night. A cold front approaches Friday,
crosses the region Friday night, then exits across the Maritimes
Saturday. High pressure builds in on Sunday, followed by a cold
front crossing the region Monday.
&&
.NEAR TERM /THROUGH TODAY/...
12:05AM Update...Areas of fog across the Gulf of Maine is
slowly working inland as the atmosphere reaches saturation. FAA
Webcams in Machias shows dense fog in place reducing visibility
to less than 1/4mi. Expecting patchy to areas of dense fog to
continue to develop over the next 1-2hrs along the Downeast
coast and issued an SPS for travel precautions overnight. Minor
tweaks to T/Td to account for areas reaching saturation now.
Inland expecting some fog to develop as well with a low level
inversion and moist boundary layer, just waiting on locations to
approach saturation (+96%). Otherwise, no major changes to the
ongoing forecast...
Previous Discussion...
Any isolated to scattered showers late this afternoon will diminish
through early this evening with the loss of diurnal heating and the
exiting short wave.
Upper ridge builds in tonight behind the departing shortwave as
surface high ridges west from the Canadian Maritimes. Moist
southerly flow at the surface will remain in place overnight. This
should allow for stratus cloud deck to build back into the area late
tonight. Patchy fog is expected late tonight across the north with
areas of fog for the coast and Washington county. Cannot rule out
fog becoming dense for Downeast areas after midnight, as HRRR
visibility guidance hints at the potential. This is far from
certain at this point, but will have to monitor for the need
for a dense fog advisory late tonight. Lows tonight are only
expected to be around the 60 degree mark for most areas.
On Thursday, an upper trof digs across the Great Lakes region.
This allows the upper level flow across our area to become more
southwest with time by Thursday afternoon. Another generally
cloudy start to the day is expected with some breaks possible by
afternoon. It should remain rain free most of the day. That
being said, a lead short wave moving northeast ahead of the main
upper trof approaching from the Great lakes region could allow
a few showers to move into the north Maine Woods and central
Highlands late afternoon. High temperatures tomorrow will be
dependent on any sunny breaks but generally expecting lower 70s
but cooler along the coast.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
An upper disturbance will lift north across the region Thursday
night in advance of an approaching upper trof. The disturbance will
help support a slight chance of showers. Otherwise, expect low
clouds to advect northward across the forecast area from the
Gulf of Maine on southerly/southeasterly winds. Could also have
patchy fog. An upper low closes across Quebec province Friday,
helping support the development of a surface low. A
cold/occluded front will extend south across the forecast area
from the surface low. Moisture increases in advance of the
front, with precipitable water values increasing to between 1.50
and 1.75 inches. Expect increasing shower chances, possibly a
steadier rain, to develop through Friday. Speed/directional
shear in the vicinity of the front, along with a jet max should
also provide enough support for a chance of thunderstorms. The
upper low approaches Friday night, while the cold/occluded front
exits across the Maritimes. Showers/thunderstorms will persist
in advance of the front early Friday night, then diminish in the
wake of the front with the deeper moisture exiting across the
Maritimes. The upper low and cold pool aloft cross the region
Saturday. Expect mostly cloudy skies along with a chance of
showers across the north and mountains Saturday. Across Downeast
areas, expect partly sunny skies with also a chance of showers.
Expect below normal level temperatures Friday/Saturday.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The upper low will exit across the Maritimes Saturday night into
Sunday. Expect decreasing shower chances Saturday night along with
mostly/partly cloudy skies. Moisture wrapping around the
exiting upper low, along with the cold pool aloft, will support
partly sunny/mostly cloudy skies along with still a chance of
showers across the north and mountains Sunday. Expect
mostly/partly sunny skies Downeast. Another disturbance and cold
front should begin to approach later Sunday night then cross
the region Monday, though timing differences still exist. This
system will bring a slight chance of showers. High pressure
should then build across the region Tuesday into Wednesday with
generally partly cloudy skies, with only the slight chance of a
shower. Expect near normal level temperatures Sunday/Monday,
with below normal level temperatures Tuesday/Wednesday.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
NEAR TERM: VFR to start at all terminals will give way to IFR
or lower conditions at southern terminals this evening and at
northern terminals overnight. Conditions should improve to MVFR
at all but KBHB between 12-16Z Thursday. Northern terminals
should then improve to VFR conditions in the afternoon.
Light and variable winds into Thursday morning, then S-SE winds
at 10 kt or less by mid-late morning.
SHORT TERM:
Thursday night...MVFR likley, probably lowering to IFR or lower.
Friday-Friday night...MVFR/IFR probable, with occasional LIFR
possible. Chance of thunderstorms into Friday evening.
Saturday...Occasional IFR possible early north. Otherwise, VFR/MVFR.
Saturday night-Sunday night...VFR, except MVFR possible at
northern terminals.
Monday...VFR, with a small chance of MVFR. W-NW winds G15-20KT
possible.
&&
.MARINE...
NEAR TERM: Winds/seas will remain below SCA levels through
Thursday. Visibility will be reduced to less than 1 NM late
tonight into Thursday in areas of fog.
SHORT TERM: Winds/seas below small craft advisory levels
Thursday night/Friday. Small craft advisory level seas possible
Friday night into Saturday. Patchy fog Thursday night. Areas of
fog Friday into Saturday. A chance of showers Thursday night.
Showers and a chance of thunderstorms Friday into Friday night.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...TWD/Sinko
Short Term...Norcross
Long Term...Norcross
Aviation...TWD/Sinko/Norcross
Marine...TWD/Sinko/Norcross
Area Forecast Discussion
National Weather Service Cleveland OH
937 PM EDT Wed Aug 16 2023
.SYNOPSIS...
High pressure will build into the region tonight before a cold
front crosses Thursday night. High pressure will return Friday
and will remain in place through early next week.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
Light winds, clear skies, and perhaps some residual low level
moisture may allow patchy fog to develop mainly in river valleys
across southeastern zones, so introduced a bit more patchy fog
to the forecast for late tonight into Thursday morning.
Otherwise, no changes made to the forecast.
Previous Discussion...
The lower clouds from west central PA through east central Ohio
continue to slowly erode as of mid afternoon in response to drier
air advecting into the region. The surface high bringing this
welcomed drier air is moving east from the Mid Mississippi Valley
this afternoon and will cross the Ohio Valley tonight. This will
lead to mostly clear skies areawide by mid to late evening, setting
up a very pleasant evening with low humidity and temperatures
cooling into the low 70s. The only exception is pockets of smoke
from Canadian wildfires. Some of the ASOS sites across NE Ohio and
NW PA have fallen to 5 to 10 mile visibilities over the past few
hours. It is hard to say if this is smoke or if it is some lingering
low-level moisture, but visible satellite loops suggest a little
smoke streaming in from the north. The latest HRRR vertically
integrated smoke forecast suggests only a bit of elevated smoke this
evening and tonight before it pushes off to the NE in response to
the deep layer flow turning SW by Thursday morning, and this seems
reasonable, so kept haze out of the forecast through tonight despite
the possibility that occasional 5 to 10 mile visibilities linger
into tonight. Any smoke will go away by Thursday morning. Lows
tonight will fall into the upper 50s/low 60s.
The developing SW flow Thursday morning mentioned above will deepen
through the day ahead of an impressive Fall-like mid/upper trough
digging into the upper Midwest and western Great Lakes. This trough
will swing across the central Great Lakes and Ohio Valley Thursday
evening into Thursday night while tilting negative before beginning
to close off over the eastern Great Lakes by Friday morning. This
will lead to a strong cold frontal passage Thursday evening into
early Thursday night as the associated surface low lifts across
northern Ontario and into Quebec. The SW flow and resultant warm air
advection ahead of the trough/cold front will raise highs into the
upper 70s/low 80s Thursday with dew points reaching the low/mid 60s
by the afternoon and evening making it feel a bit more humid. The
main limiting factor preventing higher temperatures and dew points
that would typically be expected in this scenario in mid August is
the short duration of warm/moist advection before the cold front
crosses. This will greatly reduce instability, however, the latest
RAP and HREF suggests a narrow ribbon of better low-level moisture
right ahead of the front Thursday evening which allows for a narrow
ribbon of MLCAPE approaching 1000 J/Kg. Outside of this ribbon,
instability will struggle with only a few hundred joules of MLCAPE
Thursday afternoon and evening in the warm sector. There are plenty
of dynamics to support a line of convection Thursday evening as mid-
level flow increases to 45-55 knots at the base of the mid/upper
trough progressing across the lower Great Lakes. This will lead to
40-50 knots of west-southwesterly deep layer (0-6 Km) bulk shear and
around 15-20 knots of south-southwesterly low-level (0-1 Km) shear
which will support convective organization despite the limited
instability. The most probable scenario is a line of showers and
thunderstorms progressing west to east Thursday evening with gusty
winds of 40-50 mph, brief heavy rain, and small hail, but a few
severe storms are likely as well with hail up to quarter sized and
damaging winds up to 60 mph given the ribbon of better instability
right along the front interacting with the very favorable shear and
dynamics. Additionally, cannot rule out a brief spin up tornado
where any bows/surges or line breaks occur given 0-3 Km shear
vectors looking mostly perpendicular to the line and low-level (0-1
Km) SRH values over 100 m2/s2 right along the front. The latest HREF
4-hr max updraft helicity shows a few swaths across northern Ohio
which makes sense given the shear.
Drier air will quickly move in Thursday night as the cold front
pushes east of the region, but a little wraparound moisture and the
deep mid/upper trough overhead will keep a few showers going in far
NE Ohio and NW PA into Friday morning, especially with 850 mb temps
falling to 7-8 C setting up moderate to strong lake induced
instability and NW flow across the lake. Lows Thursday night will
fall into the mid/upper 50s.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Much quieter forecast is expected through the bulk of the short and
long term periods. Lingering low level moisture, deep upper level
trough, and surface cold front will be on the verge of exiting the
forecast area to the east early Friday morning. Kept chance PoPs
across northeast Ohio and northwest PA to account for any lingering
rain showers through Friday afternoon. Surface to mid level ridging
will begin to build over the forecast area Friday as high pressure
from the Northern Plains moves eastward toward the lower Great Lakes
region. High pressure will remain in control through the end of the
short term period and will provide a prolonged period of dry
weather.
High temperatures in the mid 70s Friday will increase into the upper
70s to lower 80s by Saturday. Overnight lows will follow a similar
warming trend as they begin in the low 50s Friday night and
increase to the upper 50s to lower 60s by Saturday night.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Fairly quiet and dry forecast period as high pressure remains over
the forecast area. Above normal temperatures will be common by
Sunday with some locations touching 90 degrees Sunday and/or Monday
with upper 80s elsewhere. Highs in the low to mid 80s will persist
Tuesday and Wednesday afternoon. Overnight lows each night will drop
into the low to mid 60s each night. There are no concerns at this
time for any heat headlines as the airmass is rather dry and the
feels like temperature shouldn`t exceed 95 degrees.
&&
.AVIATION /00Z Thursday THROUGH Monday/...
Generally expect VFR at the majority of TAF sites through at
least early afternoon Thursday with haze likely diminishing at
KERI as winds shift to the south over the next few hours.
Flight conditions will begin to deteriorate from the west
as a cold front ushers showers and thunderstorms east towards
the forecast area Thursday afternoon. Showers/storms will spread
east through the rest of the TAF period, most likely reaching
KCLE/KCAK by 00Z Thursday evening.
Light and variable winds tonight will become southerly Thursday
morning and increase to 10 to 15 knots with gusts to 25 knots
likely by Thursday afternoon.
Outlook...Non-VFR possible in showers and thunderstorms into
Thursday night.
&&
.MARINE...
Quiet marine conditions through tomorrow afternoon as high pressure
continues to build over our area. Low pressure centered over Ontario
will deepen Thursday evening. This low will swing a cold front east
across the lake Thursday evening into Friday morning. High pressure
and tranquil conditions will return by the weekend.
Generally southerly to southwesterly flow 10-15 knots ahead of the
cold front. Winds will increase to 20-25 knots by Thursday afternoon
and will allow for waves will build to 3 to 5 feet. A Small Craft
Advisory will likely be needed through at least Friday afternoon but
have punted any headline decisions to the next shift. Winds behind
the cold front shift and become northwesterly with winds and waves
subsiding below small craft criteria Friday afternoon.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...Garuckas/Maines
SHORT TERM...Iverson
LONG TERM...Iverson
AVIATION...Maines
MARINE...Iverson
Area Forecast Discussion
National Weather Service Des Moines IA
853 PM CDT Wed Aug 16 2023
...Update for Near and Short Term Weather Trends...
Issued at 853 PM CDT Wed Aug 16 2023
Near term forecast is on track as isolated storms have developed
just ahead of the cold front in a very unstable, high shear
environment, but with a sizable cap between 800 and 600mb. This
has resulted in weak low level lapse rates, but lapse rates above
this cap are steeper. Current storm in Martin County, MN likely
has hail near severe limits and will be watching for any wind
gusts as well. As of now, convective allowing models (CAMs) do
not show any gusts near severe limits, likely a result of these
storms be largely elevated. These storms will scoot across our
northern counties over the next few hours.
Other adjustment revolved around Canadian wildfire smoke that
will be moving over the region late this week. The RAP and HRRR
both show high level smoke surrounding the front as it passes
through tonight into Thursday morning. The more impactful smoke
will arrive midday Thursday over northern Iowa with near surface
smoke also a possibility later in the afternoon. The high level
smoke will overspread a good portion of central and eastern Iowa
Thursday night into Friday per RAP and HRRR with the highest
concentrations of near surface smoke remaining over northern Iowa.
So, upped sky cover starting midday Thursday through Friday and
expanded spatially and temporally haze wording in the weather
grids. Depending on trends, both modeling and observational, may
need to transition this to smoke.
As a general reminder, while we may increase sky cover to account
for high-level smoke and add haze or smoke to the weather grid for
surface impacts to visibility when applicable, air quality
monitoring and issuance of any air quality advisories are the
responsibility of our partners at the Iowa Department of Natural
Resources.
&&
.SHORT TERM.../Tonight through Thursday Night/
Issued at 223 PM CDT Wed Aug 16 2023
Forecast Impacts for the week:
...Storm chances north this evening
...Quick return of heat late Friday into midweek
...Possible breaks in the heat north at times
Confidence Short Term: High
Few changes anticipated in the forecast through day 7. Overall on
track with brief cool down into early tomorrow and chances for
storms tonight far north. 12z subjective analysis shows low
pressure over southern Canada extending southwest across North
Dakota with a trailing cold front. A warm front extends into
western Iowa. Light winds over Iowa are increasing from the
southwest across portions of Nebraska early today where the gradient
is stronger. As the cool front sweeps southeast behind the low
advancing northeast toward Hudson Bay, an area of thunderstorms will
develop along the boundary this afternoon in MN and rip southwest
along the boundary toward far northern/northeast Iowa this evening.
Morning 12z H850 analysis shows a decent wave over Canada with a
couple of ripples of energy progressing southeast through tonight.
The bulk of the moisture at H850 remains in southern Canada and
northern Minnesota. There is another plume of moisture over the
Southern Plains, but that is expected to remain generally south of
the region through tonight.
The Euro deterministic model continues to be the most aggressive
with some thunderstorms advancing farther southeast while most of
the CAMS/NAM/GFS suggest a lesser risk of any storms. A fairly stout
midlevel cap continues over the region at H700 into the evening and
the Euro continues to be the only model more quickly cooling the
midlevels this evening. Upper level wind forecast shows a strong
upper level jet diving southeast into the region by 06z which should
be enough to support some storms late evening. Regardless, most
soundings don`t really support much in terms of organized
thunderstorm development and thin cape profiles suggest that any
severe chances remain low, but there may be an isolated strong
storm. Lows tonight will cool quickly over the north into the upper
50s with mid 60s central to south. Thursday remains cooler and
breezy with a brief period of stronger wind gusts of 25 to 35 mph in
the morning and winds diminishing to 15 to 25 mph by afternoon.
Highs tomorrow will reach the mid 70s north to near 80 south. Weak
warm air advection will commence Thursday evening into Friday
morning. With the ridge exiting to the east by 18z Friday, overnight
lows will remain cool and near 50 north to the lower to mid 50s
south; which is near normal for this time of year.
&&
.LONG TERM.../Friday through Wednesday/
Issued at 223 PM CDT Wed Aug 16 2023
Confidence: Medium to High
Similar challenges exist in the extended, but overall the forecast
has not changed much since yesterday. Friday continues to be the
transition day with stronger warm air advection developing east
across the region. By 00z Saturday H850 temperatures increase to 20
to 23C over the region with southwest winds by afternoon. Highs will
recover to the lower to mid 80s over the region. Looking aloft, the
H500 pattern shift still shows the ridge building into the Central
US by later Saturday and establishing itself over northeast Kansas
by 18z Monday. The Euro ens mean continues to nearly mirror
operational runs for H850 temperatures into the weekend and early
next week with mid to upper 20s across the region. There remains a
bit of uncertainty with regard to whether a front will dip south
into the southern areas Sunday afternoon and keep the northeast a
bit cooler. Overall, the high remains nearly in place for the
balance of the period with little change in the heat through the
remainder of the period, though a small shift in the heat back north
is noted by Tuesday. By Tuesday evening there is a hint that the hot
air may back off as evidenced by midweek temperature guidance spread
increasing, though the operational model/mean high still remains
well into the 90s over much of the area. The GEFs and operational
run of the GFS are still showing a weakening of the ridge by Tuesday
with a push of cooler air into the area by Tuesday, then warming
again into Wednesday. Overall, despite the minor undulations and run
to run inconsistency by midweek, there remains at least support for
hot weather through Tuesday and possibly returning later in the
week.
&&
.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 630 PM CDT Wed Aug 16 2023
While VFR conditions will prevail through the period, it is an
active period outside of visibility and ceiling concerns. A cold
front is just entering northwest Iowa and will move through
central Iowa overnight. There remains a low chance of a few
showers or storms reaching MCW this evening, but have relegated
this back to VCSH until confidence improves in thunder impacting
the terminal. Low level wind shear will develop ahead of the front
with gusty surface winds from the southwest for a few hours at
most terminals. Once the front passes, winds will be from the
northwest and will be brisk during the day Thursday. High level
smoke may also arrive over northern Iowa in the afternoon and will
address that in the next TAF cycle.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Ansorge
SHORT TERM...REV
LONG TERM...REV
AVIATION...Ansorge
AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1008 PM CDT Wed Aug 16 2023
.SHORT TERM...(This Evening through Thursday)
Issued at 255 PM CDT Wed Aug 16 2023
KEY MESSAGES:
1. Isolated thunderstorms will be possible over southwestern MN
during the evening.
2. Smoke will work back over the area overnight.
3. Turning cooler tonight into Thursday, then temperatures rebound
for the end of the week with much above normal temperatures
expected.
--------------------------------------------------------------------
Current surface analysis is indicating a cold front sweeping through
central SD this afternoon. This feature will continue to slide to
the south and east, exiting our CWA toward 06Z tonight. While there
is a possibility of convection developing with this front after 00Z
this evening, most recent hi-res models continue the trend of
keeping convection mainly to the east of our CWA - closer to the
upper level forcing. Model soundings show a strong cap over our area
out ahead the boundary, so it would be difficult for convection to
initiate, though if an isolated thunderstorm would develop in our far
eastern most counties this evening, cannot rule out a strong to
severe storm with MUCAPE values near the front around 2000 J/kg and
0-6 KM of 45 to 55 kts.
With strong cold air advection behind the front, northwesterly winds
will be breezy in the evening, though diminishing later at night.
Both the HRRR and RAP smoke model fields indicate smoke working back
over the area behind the departing front, though this should be
south of our area by Thursday morning. Most of this smoke should
remain aloft. With the cold air advection, it will be a cooler night
with dew points falling into the upper 40s to lower 50s. Lows will
be in the mid to upper 50s.
Surface high pressure builds into the Northern Plains on Thursday.
With cold air advection across the region, it will be a much more
pleasant day with highs in the mid 70s to around 80. It will be
relatively breezy early in the day, then winds will begin to
decrease by afternoon as the surface pressure gradient lessens as
the surface ridge exerts more influence.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 255 PM CDT Wed Aug 16 2023
Thursday night looks to be another coolish night with lows in the
lower 50s to near 60. Winds will increase west of Interstate 29
later in the night in response to an increasing SPF as the high
pressure slides to the east.
The cooler temperatures will be short lived as an upper level ridge
begins to build into the region on Friday, collocated with a
returning southerly low level flow as the surface highs moves into
the Mississippi Valley. In response, temperatures begin to warm as
highs creep into the 80s along and east of Interstate 29, to lower
to mid 90s west of there. As dew points reach the mid 60s over the
James River Valley and south central SD, afternoon heat indices will
climb to around 100 over those areas. It will also be a breezy to
windy day as winds increase aloft and the SPG tightens in response
to a deepening surface trough over the western high Plains.
Models are in good agreement on the upper level ridge holding across
the region on Saturday. Both the NAEFS and ECMWF ensembles have a 90
percent probability of 850 mb temperatures equal to or greater than
25 degrees C, with deterministic models indicating 850 mb
temperatures of 25 to 31 C over the area. This will result in an
even hotter day as highs climb into the 90s to lower 100s. with dew
points in the mid 60s to lower 70s, there is a high probability of
some sort of heat headline for portions of the area on that day.
Less confidence in temperatures for the beginning of next week with
models diverging on both the upper and surface pattern - especially
by Monday. The ECMWF is more aggressive in holding a stronger upper
level ridge across the region during that time frame, while the GFS
and Canadian models begin to flatten the ridge as upper level energy
over western Canada shifts eastward through the period. Even so,
both the NAEFS and ECMWF indicate a higher number of ensemble
members indicating higher probabilities of temperatures above
climatology for that period, so extended warmer temperatures are
more likely. It looks to remain dry through the period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1007 PM CDT Wed Aug 16 2023
VFR conditions will continue for the rest of the TAF period. Taking
a look across the area, any lingering showers and thunderstorms have
pushed east of the area ahead of the previously mentioned cold
front. Nonetheless, the main story continues to be the wildfire
smoke aloft. The first round of smoke has already begun entering our
area from the northwest. While near surface impacts aren`t expected,
hazy sky conditions remain possible through at least 09z tonight.
Another round of smoke will likely return to the area between 15z-
18z and likely continue throughout the day. However, near surface
impacts will be possible east of I-29 especially in areas of higher
elevation. Otherwise, breezy northwesterly winds will continue into
the day tomorrow with gusts between 15-25 kts possible. Expect winds
to decouple just after sunset tomorrow to end the TAF period.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...JM
LONG TERM...JM
AVIATION...Gumbs
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1042 PM EDT Wed Aug 16 2023
.SYNOPSIS...
Dry high pressure will maintain milder temperatures and lower
humidity to the end of the week. A weak cold front will cross the
area on Friday with little fanfare, after which the hot upper ridge
over the southern Plains will expand across the Southeast.
Temperatures will slowly climb through the second half of the
weekend and into the first half of next week.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 1035 PM: A weak upper trough will slowly move across the
region through the period. A weak wave of low pressure will move
northeast along a stalled frontal boundary to our southeast,
bringing some cloud cover and isolated showers, mainly south and
east of the forecast area tonight and early Thursday. However, a
couple of very small showers have developed across the SC Piedmont,
and we could continue to see the occasional stray shower across
mainly the southeast quadrant of the CWA through the overnight.
Fog/low stratus expected again in the mountain valleys, with low
clouds possible elsewhere. Lows will be near normal for the CLT
metro and up to 5 degrees below normal elsewhere.
Isolated showers will linger east of I-77 Thursday, with spotty
showers possible across the mountains, but generally dry conditions
expected for most locations. Low clouds should scatter out with a
good Cu field for much of the day. Highs will be near normal.
Humidity will tick up slightly but nowhere near the levels earlier
this week.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 200 PM EDT Wednesday: The short term is expected to remain
fairly quiet. The frontal boundary that was stalled to our south and
east during the near term period will finally push east Thursday
evening into Thursday night as a cold front tracks out of the
Midwest. The FROPA is expected to track across the western Carolinas
and northeast Georgia on Friday. Most locations will see a dry
FROPA; However, the 12Z GFS, ECMWF, NAM Nest, ARW, and Fv3 all show
the potential for some NW flow rain showers to develop along the
NC/TN border behind the front Friday morning. However, the 12z HRRR
and Canadian both show dry conditions Friday morning. The NAM Nest
even shows the potential for some isolated convection spilling east
of the mountains Friday afternoon, but this seems a bit overdone.
Nonetheless, went ahead and maintained a dry forecast as confidence
on how much moisture will be available with the FROPA is low. Breezy
NW winds will develop along and behind the FROPA across the NC
mountains. Gusts should range from 15 to 25 mph Friday morning and
afternoon before gradually tapering off Friday evening. Sfc high
pressure will build into the region behind the departing front
Friday night into Saturday leading to pleasant conditions and
continued dry weather. Breezy winds ranging from 15 to 20 mph are
possible Saturday morning and afternoon, mainly east of the NC
mountains. Temps will be around climo through much of the short
term.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 215 PM EDT Wednesday: Most of the long term remains quiet and
dry thanks to a large upper anticyclone building over the central
and eastern CONUS. This will lead to highs around 3-7 degrees above
climo through the period. The 12Z GFS and Canadian show an upper
trough rounding the northern and eastern periphery of the upper
anticyclone early next week while digging south across the East
Coast. This would act to drag a sfc cold front across the Carolinas
late Tuesday into early Wednesday. However, the 12Z ECMWF remains
dry as the model has the upper trough only digging as far south as
New England, which would keep high pressure in control. Went with
NBM PoPs again (continued dry weather) this forecast cycle, as
confidence is too low with model runs being inconsistent regarding
the timing of the potential FROPA. Lows will remain near climo
Saturday night, becoming 3-6 degrees above climo the rest of the
period.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: A drier air mass will result in continued
quiet/inactive convective weather through this forecast period.
Can`t rule out a shower or two making a run toward KCLT from the
south tonight, but this is unlikely, and doesn`t warrant a TAF
mention. Otherwise, the main concern will surround the potential for
another round of low stratus and/or fog in the mtn valleys early Thu
morning. Based upon the slightly drier air mass, it appears the more
significant restrictions will most likely be confined to the valleys
west and north of KAVL. Still, there is enough of a potential to
advertise MVFR BR and FEW003 at KAVL for a couple of areas
surrounding daybreak. Otherwise, VFR is expected through the period.
Winds will generally be lgt/vrbl, or maybe light NE through the
night, with a gradual transition to S/SW Thu afternoon.
Outlook: Relatively drier air should remain over the area into early
next week, with at most spotty diurnal convection expected each day.
Mountain valley fog and low stratus will be possible each morning.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...JDL/RWH
SHORT TERM...AR
LONG TERM...AR
AVIATION...JDL
Area Forecast Discussion
National Weather Service Wilmington NC
948 PM EDT Wed Aug 16 2023
.SYNOPSIS...
A stalled front over the Carolinas will weaken through Thursday
before another cold front brings drier air and limited shower
activity Friday into the weekend. High pressure will maintain dry
and very warm weather into early next week. A cold front should
drop southward by the middle of next week.
&&
.UPDATE...
Have toned down POPs for the remainder of this evening across
the majority of the FA except for the southernmost portions of
the ILM SC CWA. This based on latest KLTX and surrounding
sister radars. HRRR did not do very well with convection across
the ILM CWA this aftn into the evening..however...it has been
consistent with the nocturnal Atl convection during the pre-dawn
Thu hours and extending into the daytime morning hrs, as it
lifts NE-ward up the SC and NC Coastlines. Some of the dynamics
provided by embedded mid-level s/w trof action. Nevertheless,
have adjusted POPs late tonight into Thu, with the immediate
coast having the hier POPs when compared inland. The FA to
basically remain on the east side of the stalled front with
another muggy night and mins adjusted slightly hier.
&&
.NEAR TERM /THROUGH THURSDAY/...
Convective guidance still suggesting an increase in storm
coverage tonight with a line of slow moving showers/storms
through the center of the CWA. PWATs remain 2-2.5" so main
threat for this evening will be strong downbursts as well as
heavy rainfall which could cause local instances of flooding.
Coverage generally decreases tonight inland as activity shifts
towards the coast/coastal waters. Lows in the lower 70s.
Conditions could even be largely dry come Thursday morning for
our inland areas. The stalled front will remain west of the area
with troughing increasing aloft bringing small pulses of
shortwave energy over the area. PWATs look to decrease to 1.5-2"
for Thursday with no widespread severe weather expected at this
time as this leads to a decrease in the flooding/damaging wind
threat. Notably, the NAM and RAP show rain continuing through
Thu morning into the evening hours. Highs generally in the mid
to upper 80s, maybe near 90 inland, between the rain and the
clouds.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
Any lingering convection will dissipate into Thurs eve with loss
of heating and plenty of mid level dry air and subsidence
building in in a deeper N-NW flow. Southerly winds will increase
late Thurs into Fri between Bermuda high and front pushing
through the Carolinas.
Looks like drier northerly flow will bring dewpoints down into
the low to mid 60s inland by Fri and the dry air should bleed
toward the coast through Fri. The sea breeze may cause enough
convergence for some aftn cu, but overall convection should be
limited with increasing dry air and subsidence through the mid
levels. The drier air will maintain a warm and most sunny day
on Fri with highs low to mid 90s and overnight lows down closer
to 70.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
High pressure will build down from the Ohio Valley while Bermuda
High continues to dominate with southerly flow over the coast
and local waters. Strong ridge builds in form the central CONUS
will also maintain plenty of dry air and subsidence for the
weekend into early next week. Rising heights in the mid levels
will peak late Mon into early Tues. Therefore expect warming
across the area over the weekend into early next week with
warmest days Mon and Tues with temps into the mid to upper 90s.
The dewpoints will remain in the mid 60s to around 70 before
creeping up by Tues. Overall warm to hot and dry weather will
continue through much of the weekend into early next week. A
cold front may drop down from the north by the middle of next
week, but looks like it will only slightly increase chc of rain
by Tues night/Wed, but should bring a relief from the heat.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR this evening except for periodic MVFR from showers possibly
accompanied with thunder. Highlighted this with either VCSH/VCTS
or a tempo group. Have indicated the threat for convection
ramping up along the coast from south to north during the pre-
dawn Thu hours. Have indicated tempo groups, mainly across the
coastal terminals, to highlight the worse tstorm conditions
expected from this area of convection as it travels up the SC
and NC Coasts. Much of the activity will be north of all
terminals by noon with isolated, VCTS, convection possible from
mid aftn thru early evening mainly across the inland terminals.
Extended Outlook...VFR to dominate the upcoming extended.
Exceptions that may result in flight restrictions, late Thu
night could see patchy fog and/or low stratus as drier air will
be slow to mix in. And, isolated sea breeze convection possible
each day.
&&
.MARINE...
Through Thursday...Conditions could reach near SCA by the end
of the period with an increasing SE swell introducing 5-6 ft
waves, particularly for our NC coastal waters. Otherwise, seas
should increase from 2-3 ft tonight to 3-4 ft Thu. Southerly
winds may lull to near 10 kt Thu morning but will otherwise be
near 15 kt with 20 kt gusts.
Thursday night through Monday...Winds and seas will increase
late Thurs into early Fri in stronger southerly winds up to 25
kts. The southerly push will drive seas up to 4 to 6 ft across
much of the waters Thurs night with Small Craft Advisory
conditions likely across at least the northern waters.
A cold front pushes toward the coast Fri and may cause more
variable winds over the weekend as Bermuda High pressure
weakens. Should see land breeze/sea breeze become more dominant
near shore with lighter winds and limited chc of shwrs/tstms
over the weekend into early next week.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...High Rip Current Risk from 6 AM EDT Thursday through Thursday
evening for SCZ054.
NC...High Rip Current Risk from 6 AM EDT Thursday through Thursday
evening for NCZ110.
MARINE...None.
&&
$$
SYNOPSIS...ILM
UPDATE...DCH
NEAR TERM...LEW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...DCH
MARINE...RGZ/LEW
Area Forecast Discussion
National Weather Service Medford OR
236 PM PDT Wed Aug 16 2023
.DISCUSSION...High temperatures will continue this afternoon into
the evening. West side valleys are going to reach triple digits
again, while other inland areas will generally be in the mid to high
90s and the Oregon coast will be in the high 70s to low 80s. These
temperatures are about 10 degrees above normal for all areas, and
can be hazardous. An Excessive Heat Warning remains in place or
inland areas west of the Cascades through 5 AM on Thursday and a
Heat Advisory continues for areas east of the Cascades.
Chances for thunderstorms and precipitation remain focused on the
east side this evening. A plume of moisture is moving into the area
over Lake and Modoc counties and will continue northwest through the
evening. Radar imagery is showing 35 dBz returns and no lightning
strikes have been detected yet. 20-35% chances for precipitation
will persist over northern California and across the east side
through Thursday evening. Chances for thunderstorms are at similar
levels, with the highest chances in the late afternoon and early
evening hours.
Smoke continues to be a concern, especially with new wildfires
ignited by recent thunderstorm activity. Smoke from two new groups
of wildfires, the Klamath National Forest Lighting Complex (western
Siskiyou County) and the SKU Lightning Complex (southeastern
Siskiyou County), is visible on satellite imagery. HRRR guidance
shows smoke from these complexes moving over the northern California
border and affecting Curry, Josephine, and Jackson counties. And
smoke from the Bedrock and Lookout fires continues to affect areas
east of the Cascades.
For Thursday, temperatures start to cool across the area as low
pressure works to break the upper ridge down. The Oregon coast will
see temperatures in the low to mid 70s, while west side valleys will
be in the mid to high 90s. Areas east of the Cascades will be in the
low to mid 80s. While these temperatures no longer require Excessive
Heat Advisories, the conditions in west side valleys can still
affect vulnerable individuals. Existing warnings have been replaced
with Heat Advisories for the Rogue, Umpqua, and Illinois Valley to
indicate that conditions are still hazardous, even if that hazard is
decreased. These Advisories are scheduled to end Thursday at 11 PM.
The area is expected to be under an upper level trough through the
weekend, which will allow for temperatures to stay at seasonal
levels. Slight (15-25%) diurnal precipitation chances across the
east side and northern California will continue through the weekend,
rising to the highest chances in the afternoon and evening before
decreasing overnight.
Model guidance generally agrees that the area will remain between a
Pacific trough and ridging centered over the central United States.
One area of uncertainty is whether tropical storm remnants will be
able to travel far enough to the north to affect this region.
Outcomes from the ECMWF show these remnants bringing precipitation
by Tuesday afternoon and evening, while the remnants dissipate over
central California in the GFS outcomes. There`s more certainty in
temperatures remaining seasonal. Using Medford as a guideline,
there`s only a daily 20% chance of seeing triple digit temperatures
through next week. -TAD
&&
.AVIATION...16/18Z TAFs...The marine layer off the coast should
diminish soon which would allow for North Bend (KOTH) to get some
relief from IFR conditions. Thereafter, all the terminals should be
VFR, but the next potential concern for categorical changes will be
later this afternoon and evening when thunderstorm chances ramp up.
KOTH will likely not see these thunderstorm. Roseburg has as small
probability (10%-20%) to see thunderstorms, but really if any site
sees convection its better for Medford (~25%) and Klamath Falls
(~30%). Since thunderstorms will be more scattered in nature, we
decided on a vicinity mention at this time due to uncertainty of
impacting the terminal and low confidence. Otherwise, mid to high
clouds will likely infiltrate across southern Oregon through
tomorrow from thunderstorms in the region.
-Guerrero
&&
.MARINE...Updated 200 PM PDT Wednesday, August 16, 2023...Moderate
to advisory strength north winds are expected today, especially
south and southwest of Port Orford. Additionally, wind-driven seas
combined with northwest swell will create steep seas through the
entire region through the weekend. Therefore, a Small Craft Advisory
for all of the waters is expected through at least Saturday. Winds
will further increase Friday, but some uncertainty remains to
exactly how strong those winds speeds will be Friday
afternoon/evening. Either way, this will produce steep to very steep
seas across all of the waters, with gale force gusts possible south
of Port Orford Friday and Saturday. A Gale Watch for this area has
been issued to reflect this.
A look at probabilities from the National Blend of Models (NBM)
continues to indicate an upward trend in wind speeds Friday and
Saturday. For areas south and southwest of Cape Blanco, here are
some exceedance probabilities from the NBM:
* Sustained Winds:
- 40%-50% chance to exceed 34 knots
* Gusts:
- 80%-95% chance to exceed 41 knots
- 40%-70% chance to exceed 48 knots
These are moderate to high probabilities for Gale (to high end
Gale) Force Winds to develop, especially the gusts aspect.
-Guerrero
&&
.FIRE WEATHER...Updated 200 PM PDT Wednesday, August 16, 2023...The
two big weather concerns for the forecast period will be
heat expected today into Thursday and the thunderstorm potential
also continuing through the week.
A very hot air mass remains over the area today with hot
temperatures similar to yesterday. 100+ degree high temperatures
are anticipated again west of the Cascades with mid to upper 90s
east of the Cascades. High temperatures will trend lower/less hot
Thursday, but still expect very warm to hot temperatures across the
area. Humidities will remain low today, but with moisture moving
into the area form the south, improvement is expected into this
weekend.
This same influx of moisture will produce an increased risk for
thunderstorms. This afternoon and evening, expect a mix of isolated
to scattered thunderstorms along and east of the Cascades and
along and south of the Siskiyous. Isolated showers and thunderstorms
are also possible in southeast Jackson County and far southeast
Josephine County. A Red Flag Warning for abundant lightning on dry
fuels remains in effect for Fire weather zones 280, 281, 282, 284,
285, 621, 623 and 624 for this afternoon and evening. Storms are
expected to have relatively high bases today, so rainfall may be
limited outside of the cores of these storms. Additionally, gusty
outflow winds (30 to 40 mph) are expected near thunderstorms.
Models support the potential for isolated to scattered rain showers
and isolated thunderstorms across inland areas tonight and Thursday
morning. Then, as a deeper moist layer arrives Thursday
afternoon/evening, with isolated to scattered thunderstorms across
areas inland of the coast range. The highest chance for scattered
thunderstorms is from the western foothills of the Southern Oregon
Cascades and eastward, over the Siskiyou Mountains, and into
Siskiyou and Modoc Counties. Confidence is moderate for scattered
thunderstorms developing on Thursday, and may be limited by residual
cloudiness and smoke. Storms will trend wetter on Thursday. However,
lightning strikes outside of storm cores remain a concern.
Additionally, some gusty outflows (30 to 40 mph) are expected with
any stronger storms, especially east of the Cascades. The Fire
Weather Watch that was previously in effect for these areas has
been upgraded to a Red Flag Warning.
Late this week and into the weekend, the low offshore of California,
that has acted to push moisture into the region, will slowly push
east. This will limit moisture inflow to portions of our area, and
thunderstorm chances will gradually retreat to the east as well.
Above normal temperatures will continue through the weekend, with
humidities trending a bit higher. There are some indications that
tropical moisture may stream into the area next week, as the
remnants of a tropical storm push north into southern California.
Confidence is low, but should this occur, more substantial rainfall
is possible for at least some portions of our area. We will keep an
eye on this over the next several forecast cycles.
-CC
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 PM PDT this evening for ORZ621-623-
624.
Red Flag Warning from 2 PM to 11 PM PDT Thursday for ORZ617-621-
623>625.
Excessive Heat Warning until 5 AM PDT Thursday for ORZ021>024-
026-028.
Heat Advisory from 5 AM to 11 PM PDT Thursday for ORZ023.
Heat Advisory from 5 AM to 11 PM PDT Thursday for ORZ024-026.
Excessive Heat Warning until 5 AM PDT Thursday for ORZ025-027.
Heat Advisory until 11 PM PDT this evening for ORZ027-030-031.
Heat Advisory until 11 PM PDT Thursday for ORZ028-029.
CA...Excessive Heat Warning until 5 AM PDT Thursday for CAZ080>082.
Red Flag Warning until 11 PM PDT this evening for CAZ280>282-284-
285.
Red Flag Warning from 2 PM to 11 PM PDT Thursday for CAZ280>282-
284-285.
Heat Advisory from 5 AM to 11 PM PDT Thursday for CAZ081.
Heat Advisory until 11 PM PDT Thursday for CAZ084-085.
PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT Friday
for PZZ350-356-370-376.
Gale Watch from Friday morning through Saturday afternoon for
PZZ376.
&&
$$
TAD/BPN/JWG
Area Forecast Discussion
National Weather Service Pocatello ID
206 PM MDT Wed Aug 16 2023
.SHORT TERM...Tonight through Thursday Night.
Hot weather will continue into Thursday. Smoke from wildfires across
the Pacific Northwest will work into eastern Idaho from Montana this
evening and linger into Thursday morning. The 12z HRRR smoke model
shows most of the smoke lifting out of east Idaho Thursday
afternoon. Hot weather will continue into Thursday with comparable
temperatures to what we have today. Heat risk values continue to
look marginal for Thursday, given that temperatures are not
appreciably warmer and most of the area is cooling into the 50s or
low 60s will likely hold off on heat headlines. We should see the
start of the advertised monsoon push Thursday. The high resolution
models are showing isolated development late Thursday afternoon
across south Idaho spreading into east Idaho into Thursday evening.
Precipitable water values exceed an inch when the monsoonal push
arrives. Some brief heavy downpours will be possible tomorrow
afternoon and evening, although at this time, the storms do not look
overly intense and appear to be moving.
13
.LONG TERM...Friday through Next Wednesday.
The long term period begins with a closed low off the CA coast, a
weak ridge just to its east, and another upper trough to our north
across the PNW. Southwest flow will continue to usher in monsoonal
moisture, with chances for showers and thunderstorms increasing
throughout the weekend as the disturbance off the coast of Mexico
rotates northward along the CA coast. Models continue to show
differences regarding its exact track, which will impact rainfall
totals through early next week. Ensembles consistently indicate
precipitable water values running just over 200% of normal daily for
much of southeast Idaho and the Weather Prediction Center has
included portions of eastern Idaho in a marginal risk of excessive
rainfall Friday and Saturday, with all of Idaho included by Sunday.
The National Blend shows around a quarter of an inch to 1" of liquid
precipitation accumulating across the highlands and mountains with a
quarter of an inch or less in the valleys and low elevations through
early Monday. The 75th Percentile indicates up to 1" in our higher
elevations, with up to half an inch down lower. For the high-end
scenario, there is around a 10% chance of up to 1.5" accumulating in
our highlands with up to 0.75" across our lower elevations. Winds
will be strongest Friday as a strong upper jet mixes to the surface,
bringing widespread sustained winds of 15-30 mph and gusts around 30-
45 mph. Winds won`t be quite as strong on Saturday but will remain
breezy throughout the weekend. Temperatures will decrease to around
normal by Friday and continue decreasing, steadily running below
normal through the middle of next week. Cropp
&&
.AVIATION...VFR conditions forecast area-wide with high pressure in
control. Generally only FEW high clouds across southeast Idaho today
before cloud cover increases southwest to northeast tomorrow
afternoon. Smoke from regional wildfires could begin to impact
visibility over the next couple of days, however VIS is expected to
remain VFR. Winds will begin to increase tomorrow afternoon, with 15
to 20 KT gusts anticipated. Hi-res models show isolated to scattered
showers and thunderstorms working into southeast Idaho around 18z,
first near KBYI and continuing to spread further north and east in
the vicinity of the remaining terminals. Cropp
&&
.FIRE WEATHER...Hot weather continues into Thursday. The monsoonal
moisture arrives on Thursday and afternoon humidities will be
slightly higher. Isolated to scattered thunderstorms will work into
south Idaho during the afternoon and spread through east Idaho
during the evening. Cooler temperatures, higher humidity, and
continued chances for isolated to scattered thunderstorms will
continue through the weekend. Some storms will produce gusty erratic
winds and heavy downpours.
13
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service San Angelo TX
756 PM CDT Wed Aug 16 2023
...New AVIATION...
.SHORT TERM...
(This evening through Thursday)
Issued at 222 PM CDT Wed Aug 16 2023
A good cumulus field has developed from the Concho Valley south
to Ozona, Sonora and Junction this afternoon. With the HRRR model
showing some isolated convection, added mention of isolated
thunderstorms through 7 PM.
Otherwise, hotter Thursday with highs of 105 to 110, as high
pressure aloft intensifies over the region. An excessive heat
warning has been issued for all of West Central Texas Thursday 1
PM to 7 PM. Fuels and vegetation remain extremely dry. A rangeland
fire danger statement is in effect today, and will likely be
issued again for Thursday.
&&
.LONG TERM...
(Thursday night through next Wednesday)
Issued at 135 PM CDT Wed Aug 16 2023
Excessive heat will be firmed entrenched across West Central
Texas through the weekend, as the upper level high re-establishes
itself over the Plains. Friday looks to the hottest day in the
forecast period, with the center of the upper high over Oklahoma
and the 850mb temperatures exceeding 30C across the Big Country
and Concho Valley. Highs on Friday will soar into the 105-111
range, and excessive heat warnings will be needed. Highs over the
weekend may be slightly `cooler`- in the 103-108 range, but still
well above normal. Additional heat products will be needed.
As we go into the beginning to middle of next week, the upper
high shifts a bit further to the north of our area. This will
allow moisture levels to increase as well as temperatures to
decrease a bit especially by Tuesday and Wednesday. Still low
confidence as far as any appreciable rain chances for our area
next week but will continue to show a slight chance of PoPs.
Otherwise, expect dry conditions to persist through the weekend.
&&
.AVIATION...
(00Z TAFS)
Issued at 729 PM CDT Wed Aug 16 2023
VFR conditions are expected over the next 24 hours, light and
variable winds overnight and light southerly winds come the
morning hours. A few isolated showers are possible near KSOA, but
with lower confidence, we only added a few hours of VCSH to the
KSOA TAF through 03Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 77 107 78 108 / 0 0 0 0
San Angelo 78 107 78 109 / 10 0 10 0
Junction 77 107 76 108 / 10 10 0 0
Brownwood 75 108 76 109 / 0 0 0 0
Sweetwater 79 108 78 108 / 0 0 0 0
Ozona 77 103 76 104 / 10 0 0 0
Brady 76 106 77 107 / 0 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 1 PM to 9 PM CDT Thursday for Brown-
Callahan-Coke-Coleman-Concho-Crockett-Fisher-Haskell-Irion-Jones-
Kimble-Mason-McCulloch-Menard-Nolan-Runnels-San Saba-Schleicher-
Shackelford-Sterling-Sutton-Taylor-Throckmorton-Tom Green.
&&
$$
SHORT TERM...04
LONG TERM....42
AVIATION...TP