Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/03/23
Area Forecast Discussion
National Weather Service Buffalo NY
1034 PM EDT Wed Aug 2 2023
.SYNOPSIS...
Arrival of a warm front will bring some showers and a thunderstorm
late tonight into the eastern Lake Ontario region. There will be
more unsettled pattern across the region Thursday and Friday, with
showers and thunderstorms at times as a cold front moves crosses.
High pressure will build back across the area for the weekend with
dry pleasant summertime weather.
&&
.NEAR TERM /THROUGH FRIDAY/...
Going forecast is generally on track overnight into Thursday
morning. Primary shortwave trough with numerous showers and
thunderstorms this evening remains well to the north between Lake
Superior and James Bay. Secondary sfc trough that dropped across the
upper Great Lakes this afternoon helped kicked off decent
complex of storms. Most of these storms are dropping across
Lake Michigan now, but as tail of shortwave to the north and
lingering convection to the west all work east along with an
advancing warm front and some elevated instability, expect the
clusters of showers and some thunder that are filling in to the
south of Georgian Bay to continue rolling east and expanding,
especially impacting areas as far south as the south shore of
Lake Ontario but mainly to the east of Lake Ontario across the
North Country late tonight toward daybreak on Thursday. Otherwise,
will be a warmer night with lows ranging from the upper 50s to
lower 60s.
Thursday will be notably warmer and more humid in the wake of the
warm front. Expect the vast majority of the day to be rain free,
except across eastern portions of the forecast area where some
instability showers and thunderstorms are possible. This should
allow temperatures to rise towards the higher range of model
guidance, reaching well into the 80s across lower elevations. Smoke
may briefly lower resulting in haze across parts of Western NY
during the day.
There`s still fairly good model agreement that a convectively driven
shortwave will drop across the region Thursday evening, with
NAM/RGEM/ECMWF as well as 48 hr runs of the HRRR all showing this.
It would track across the Eastern Lake Ontario region, with possibly
some storms also developing south of Lake Ontario Thursday night.
There will be ample instability in place (still 1000 to 1500 J/Kg),
and wind shear will increase due to the convective shortwave. This
will pose a severe weather risk, especially east of Lake Ontario
where the primary risk is strong gusty winds between 5 p.m. and
midnight. SPC has a marginal risk for the northern half of the
forecast area, and would not be surprised if a small slight risk
area is introduced east of Lake Ontario at some point.
The shortwave and trough axis will gradually exit to our east on
Friday, while an associated cold front also moves through. Most
model guidance has the timing of this on the early side to take
advantage of diurnal heating. This will help mitigate the severe
weather risk, but could see some strong to severe storms develop
along our eastern cwa borders mid-day before the front exits to
our east late in the day. This is consistent with the SPC
marginal risk. A few storms may also produce locally heavy
rainfall, but PWAT values are modest around 1.5 inches, and
storms should be moving which will limit the risk for flooding.
Otherwise, Friday will be cooler with highs in the mid 70s to
around 80.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
Surface cold front will lie just east of the forecast area moving
into Friday night as it pushes further into central NY. Primary axis
of the longwave trough over eastern Canada will follow quickly in
its wake. While shower and thunderstorm coverage will quickly taper
off Friday night, moist cyclonic flow will linger and may allow a
few light showers and additional cloud cover to develop on the
backside of the front. A bit of model discrepancies noted about how
cool 850H temps get overnight as well, which look marginal for some
lake enhancement and may allow showers and clouds to linger a bit
longer. Regardless, a progressively drier airmass will be filtering
into the region as high pressure builds southeast from the upper
Great Lakes and bring an end to the leftover showers later in the
night. Lows will be on the cooler side with temperatures in the 50s
for most areas, though a bit warmer in the low 60s near the
lakeshores with onshore flow.
Quiet, fair weather on tap for the remainder of the weekend as mid-
level ridging and surface high pressure continuously builds
southeastward across the eastern Great Lakes. Could be a few stray
showers or a thunderstorm later Sunday afternoon in the far
western Southern Tier as a warm front lifts into the region from
the Ohio Valley, though mostly dry weather is expected to hold
for the most part. Temperatures will be seasonable Saturday with
mid and upper 70s, and cool Saturday night with temps again in
the 50s, though as the ridge moves east of the region Sunday
expect a small boost to daytime highs with upper 70s and low
80s.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Shower chances increase with the start of the next work week.
Forecast guidance is in fairly good agreement that a progressive
shortwave trough and surface low pressure will move from the Mid-
West, across the Great Lakes and across the Saint Lawrence Valley
Sunday night through Monday night. Initially, warm, moist air
associated with a low-level jet will move into the region Sunday
night and showers will move into the region. A cold front will trail
behind the surface low and move across the region Monday-Monday
night. There are timing differences, but thunderstorms are possible
with the potential for some strong thunderstorms especially if
surface based instability increases ahead of the cold front. Weak
cold air advection will occur with another surface low approaching
the area from the Mid West mid-week.
Temperatures will trend near normal Monday to slightly below normal
Tuesday and Wednesday.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Exiting high pressure will maintain fair weather and VFR flight
conditions into the early overnight hours.
Weak warm advection ahead of an advancing warm front is starting to
develop showers and some thunder south of Georgian Bay. These will
continue rolling east overnight and may impact KART after 08z (brief
MVFR conditions possible). Low risk that some showers could clip
KROC briefly after midnight as well. Elsewhere expect VFR flight
conditions.
Expect mainly rain-free and VFR flight conditions for Thursday
through mid-afternoon. Scattered showers and thunderstorms
possible across central NY, but these should not impact any TAF
sites.
Outlook...
Thursday night and Friday...VFR/MVFR with periods of MVFR in showers
and thunderstorms.
Saturday and Sunday...VFR.
Monday...VFR/MVFR. Showers likely with a chance of thunderstorms.
&&
.MARINE...
Southerly winds will freshen a bit the rest of tonight...but
conditions will remain below small craft advisory levels with any
noticeable uptick in wave action being directed into Canadian
waters. The only possible issue tonight will be the risk for
thunderstorms on Lake Ontario after midnight.
On Thursday...moderate southwesterlies will be found throughout the
region. There will be the continued potential for thunderstorms on
Lake Ontario...especially during the evening hours and through
Thursday night.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Apffel/RSH
NEAR TERM...Apffel/JLA
SHORT TERM...PP
LONG TERM...HSK
AVIATION...Apffel/HSK/JLA
MARINE...Apffel/RSH
Area Forecast Discussion
National Weather Service State College PA
1101 PM EDT Wed Aug 2 2023
.SYNOPSIS...
One more comfortable day with seasonable temperatures and low
humidity. Smoke aloft will continue to create hazy skies across
the western half of central PA. An uptick in humidity will
correspond to an increased risk of showers and thunderstorms
mainly during the afternoon Thursday and Friday. A tranquil
first part of the weekend will precede a stormy start to next
week.
&&
.NEAR TERM /THROUGH THURSDAY/...
11 PM Update also contains few changes, and mainly to sky (upped
a bit) and T/Td. The cirrus does look like it should move east
through the night, but likely still be around most of the night,
esp in the NE. There may be stargazers out there, and the
cirrus (and smoke) may blur the view of anything they would be
interested in. The moon is pretty bright right now, but the
Perseids will be visiting in the middle of the month.
Prev...
7 PM update is mainly to tighten up the T/Td. Td rising slightly
in most places. Sky cover looks OK w.r.t. current sat images.
Lots of smoke makes it tough to separate what is clouds - or at
the least what is perceived as clouds - from the smoke.
Rising 500mb heights and seasonably strong high pressure with
accompanying low pwat air will maintain fair wx today. RH
timesections indicate early sunshine will give way to a mix of
sun and cumulus into the afternoon. The latest HRRR continues to
keep the greatest concentration of high level VI smoke over
western PA through much of the day, however some hazy skies are
likely at times. Fcst highs will be neutral or trend warmer day
over day with maxTs up to +5F higher vs. yesterday in the mid
70s north to low 80s south.
Main target of opportunity today is trimming dewpoints this
afternoon. Clear skies across the eastern half of the state and
sufficient dry air aloft could combine to produce drier-than-
forecast air at the surface and lower relative humidities. There
is really no sensible weather impact with lower relative
humidity, but it is a good day for some of our fire management
partners to get some prescribed burning done.
The sfc high slides eastward to the mid-Atlantic coast tonight.
Return southerly flow will start to increase dewpoints/llvl
moisture with minT making the first in a series of higher lows
into the weekend (+5-10F warmer vs. this morning). Another dry
night is in store as the smoke plume aloft gradually drifts
east- northeastward.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
500mb height falls Thu-Fri associated with shortwave trough
rotating through the Northeast CONUS combined with diurnal
heating and instability ahead of sfc cold front should result
in an uptick in showers and t-storms Thursday afternoon and
Friday. The trend has been for less and less convection on
Thursday with successive model runs, but a few showers are
expected and light to moderate rain is expected. Any outdoor
plans Thursday evening won`t necessarily be a washout, but any
locations that receive rain could accumulate a quarter to half
an inch.
There is better overall forcing and shear on Friday to warrant
a MRGL severe risk (level 1 out of 5) over a portion of north
central PA. Coverage of showers and thunderstorms will be more
widespread on Friday compared to Thursday, with a higher
concentration across the eastern half of the Commonwealth. A
cold front will sweep through the area during the day on Friday
and combine with diurnal heating to create convection initiation
across the Central Mountains by midday and intensification
farther east. After the cold front sweeps through, low- pwat
air associated with sfc high pressure will return Friday night
into Saturday AM and will provide a nice start to first weekend
of August.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The latest GEFS and ECENS both support a return to fair and
seasonable weather this weekend, as the cold front passes well
south of PA and high pressure builds in from the Grt Lks. The
chance of showers returns Sunday PM associated with a returning
warm front lifting in from the Ohio Valley. By Monday, surface
low pressure tracking over the Great Lakes will drag a cold
front through the area. A deep southwest flow preceding this
front will advect a seasonably moist air mass into the region
ahead of the front, supporting a good chance of convection. Both
the GFS and ECMWF support the potential for some stronger storms
on Monday afternoon with surface CAPE of 1000-1500 J/kg ahead
of the front. Latest ensemble plumes suggest areal average
rainfall between 0.25 and 0.50 inches is likely Sunday
night/Monday, with locally higher amounts under any stronger
storms.
The long term outlook indicates that persistence will be a good
forecast - upper troughing across the east coast should limit
any extreme heat in the area and ensure occasional chances for
beneficial rainfall.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Wildfire smoke continues to drop visibilities to borderline
VFR/MVFR across western portions of the area. This could
continue for the next few hours before the greatest near surface
smoke concentration shifts back to the west.
Light winds tonight may bring patchy valley fog again to the
mountains of Central PA. Confidence in any of the TAF sites
seeing restrictions from fog was too low to include in the 00Z
TAF package. Mid and upper level cloud cover will increase
through the day tomorrow and some isolated showers and
thunderstorms will be possible late in the afternoon.
Outlook...
Fri...Restrictions will be possible in showers and
thunderstorms.
Sat...Mainly VFR.
Sun-Mon...Showers and thunderstorms may result in some
restrictions.
&&
.CLIMATE...
Low of 50 degrees this Wednesday morning in AOO (Altoona) tied
record of 50 degrees set in 1998.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Steinbugl
NEAR TERM...Dangelo/Banghoff
SHORT TERM...Steinbugl/Banghoff
LONG TERM...Banghoff/Bauco
AVIATION...Bauco/RXR
CLIMATE...Martin
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
339 PM PDT Wed Aug 2 2023
.SYNOPSIS...Below normal temperatures are expected through
Thursday in the interior, followed by hotter weather this weekend.
Isolated thunderstorms will be possible in far northeastern
Trinity County on Friday and Saturday, otherwise dry weather is
expected for the next 7 days. Widespread and more persistent
coastal stratus is forecast through Friday.
&&
.DISCUSSION...Another day with quiet weather conditions across
Northwest California. Satellite pictures show plenty of sunshine
skies in the interior with pocket of cumulus clouds over the
higher terrains in Trinity County this afternoon. Meanwhile,
stratus persist along much of the coast this afternoon with areas
seeing some sunshine. Onshore flow will push back inland the
stratus later this afternoon and evening. The marine layer is
expected to slightly deepen tonight through Friday.
Smoke from the active wildfire in southwestern Oregon will
continue to take a trajectory southward over NW California
overnight through mostly the morning hours during the week. HRRR
smoke dispersion model indicates more waves of smoke from the Flat
fire spreading southward through the next 48 hours. However, most
of the smoke is staying aloft allowing good AQI in most areas.
Daytime high temperatures will decrease today and remain slightly
below normal in the interior through Friday. A shortwave trough
will move toward the area Thu into Fri. Thursday appears too dry
and stable for storms over NW California. However, high-resolution
guidances are showing some light to moderate convection returns
in the edge of the Trinity Horn and Siskiyou County. The potential
for isolated thunderstorms increase on Friday with CAPE and
elevated instability in NE Trinity where the National Blend of
Models indicates the highest probabilities for diurnally
triggered- terrain forced storms. PWATs increase to around 0.70 to
0.90 on Friday. This will will probably produce some rain (less
than 0.10) as well as gusty outflow winds with those storms.
Isolated dry strikes outside the main cores may still occur,
however.
Saturday, the weak upper disturbance will remain over the northern
portion area and will triggered to another chance for isolated
thunderstorm development over the NE Trinity County in the
afternoon. NBM have a chance of thunderstorm up to 20% for
Saturday afternoon and evening. With PWATs remaining around 0.80
inches are expected some light rain with those storms.
There are no changes for the extended forecast. Upper ridging
will begin to expand and strengthen on Sat as the offshore trough
lifts out and weakens. There is an 80% chance for 100F or more in
portions of Lake and southeast/eastern Mendocino Counties on
Sunday, however the heat risk is moderate at the moment. Some
valleys in Trinity and NE Humboldt will also warm above 100F, a
90% chance for Orleans and Big Bar. The chance for 100F or more
diminishes to 45-50% for Weaverville, Hoopa and Redway. Coastal
areas could warm to a sweltering 70F (20% chance or less) this
weekend. Also, smoke from Oregon fires may also spread south over
and into NW California this weekend. So far the smoke layer has
been aloft and not dense with unhealthy to hazardous
concentrations. Temperatures should start to diminish Tue and Wed
of next week (Aug 8/9) as another trough flatten out the ridge. It
will remain hot with near normal interior temperatures in the
lower to mid 90s. Breezy to locally windy conditions are expected
every day for the next 7 days.
&&
.AVIATION...Visible satellite imagery shows a shallow marine layer
persisting along much of the coast. Low clouds burned off for much
of the immediate North Coast by late morning and a small scale
eddies moving southward along the Humboldt Coast, helping to
improve conditions to VFR at KACV early this afternoon. Meanwhile,
variable conditions have been observed at KCEC with ceilings
around 900 to 1300 feet between BKN-OVC. Expect onshore winds
will push back stratus into the immediate coast late this
afternoon, deepening to LIFR conditions later tonight. With the
marine layer deepening tonight, stratus will push farther inland
closer to UKI by Thursday morning. However, VFR conditions
is expected to prevail at KUKI. Breezy NW winds with gusts around
20 kts has developed during the afternoon and is expected to ease
during the evening.
&&
.MARINE...Winds and waves remain light this afternoon. Winds are
around 10 to 15 kt aside from the northern inner waters where they
are only 5 to 10 kt. Waves are around 2 to 4 feet at 5 seconds out
of the northwest and 2 feet at 9 seconds out of the northwest. In
addition there are some small waves out of the south at around 13
seconds. These conditions are expected to continue tonight and
Thursday.
Late Thursday night into Friday winds and waves are expected to
start to increase again with speeds around 20 kt off the coast.
Saturday the winds are expected to continue increase peaking in the
afternoon with some gale force gusts across much of the outer
waters. A gale watch may be needed on future shifts, but for now it
is low end and still 3 days out. Sunday winds are expected to remain
elevated, although they may drop below gale force in some areas.
Next week the diminish trend is expected to continue with winds of
15 to 20 kt by Wednesday. MKK
&&
.FIRE WEATHER...Forecast continue on track. Warm dry weather
conditions with slightly below normal temperatures are forecast
through Thursday. There is the potential for a isolated
thunderstorms on Friday and Saturday afternoon/evening over far
northeast zone 283 as an upper level disturbance moves through.The
storms will produce some rain (less than 0.10). Isolated dry
lightning is possible too (10% chance) as well as gusty outflow
winds. Otherwise, breezy (15-25 mph) west and northwest winds will
occur each afternoon through channeled terrain and exposed ridges
through Friday. Overnight RH recoveries have improved some,
however daytime minimum RH`s will continue to bottom out around 15
to 25% in Trinity, eastern Mendocino and Lake Counties. Hotter
temperatures, lower daytime RH`s and gusty afternoon winds are
expected for this weekend. In addition, very poor overnight RH
recoveries are expected this weekend into early next week for
exposed ridges and higher elevations in mostly zones 264, 277 and
276. Elevated to locally critical conditions due to low RH`s and
gusty winds will increase this weekend and persist into early next
week.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 3 PM PDT this afternoon for
PZZ455-475.
&&
$$
Visit us at https://www.weather.gov/eureka
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https://www.facebook.com/NWSEureka
https://www.twitter.com/NWSEureka
For forecast zone information
see the forecast zone map online:
https://www.weather.gov/images/eka/zonemap.png
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
730 PM EDT Wed Aug 2 2023
.UPDATE...
Issued at 723 PM EDT WED AUG 2 2023
Not many changes made to the grids aside from loading in the most
recent surface obs and adjusting via cooling trends. Otherwise,
touch-ups in preparation for TAF issuance. Lastly, updated radio
and text products to reflect the changes. Grids have been saved
and sent.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 450 PM EDT WED AUG 2 2023
Late this afternoon, an upper level ridge extended from the Lower
MS Valley and northern Gulf of Mexico across the Southern Plains
into northern Mexico. Meanwhile, the axis of an upper level
trough extended from eastern Canada into the Northeast to western
Atlantic to eastern seaboard with another trough was located over
the eastern Pacific. This upper pattern leaves KY in northwest
flow aloft between the trough to the east and the upper ridge to
the southwest. Multiple disturbances in northwest flow are moving
from the upper MS Valley and portions of the midwest toward the
Lower OH Valley and Appalachians. The most potent of these was
currently over the IA vicinity. At the sfc, high pressure a ridge
of high pressure was centered over the Northeast to the Carolinas
to GA including portions of the southern Appalachians. Further
south and southwest, a frontal zone currently extends from the
southeast to the vicinity of the Ozarks to the Central Plains
with one or more sfc waves moving along it. However, return flow
over the TN and OH Valley has allowed surface dewpoints to climb
back into the 60s and well into the mid to upper 60s across
southern portions of the area. With nearly neutral height
tendencies at 500 mb, daytime heating has led to a few very
isolated showers developing near the TN border and potions of the
southeast coalfields.
This evening and tonight, the diurnally driven convection should
wane over the next few hours with a lull in convective activity
during the evening. However, strong convection is expected to
develop in the mid MS Valley and St Louis vicinity this evening
and eventually track into the Lower OH Valley and TN Valley to
southern Appalachians late tonight associated as the shortwave
trough currently in the IA vicinity moves to the Lower OH Valley
near sunrise. This shortwave is expected to trek east and
southeast to the southern Appalachians on Thu afternoon and then
to the Carolinas on Thu evening. At the same time, this shortwave
will interact with the sfc frontal zone that should gradually
lift toward the TN Valley and mid MS Valley region tonight to
early on Thu as a sfc wave moves from KS into MO. This sfc wave is
expected to reach the Lower OH Valley by late Thu night as the
front lifts into western KY and western to middle TN to AL and GA.
An additional shortwave or two in northwest flow may interact
with this boundary on Thu night and like tonight interact with a
LLJ to focus areas or a complex of convection/MCS.
The consensus of guidance generally tracks the stronger convection
later tonight closer to the frontal zone or generally into
western KY to southern parts of central KY and western to middle
TN to the southern Appalachians and southwest of of much of
eastern Ky tonight. This convection is expected to spread further
north and east around or shortly after dawn on Thursday with the
stronger convection and higher QPF expected to be near the TN
border per guidance consensus and 12Z HREF data. This convection
should begin to taper off from northwest to southeast by mid day
to early afternoon on Thu. However, additional convection could
affect the region on Thu night. Recent 18Z HRRR data suggest a
track generally west and southwest of eastern KY as does some of
the other recent guidance so it is possible that Thu night pops
may need to be lowered at a later time. PW is progged to increase
to near the 2 inch mark later tonight to early on Thursday in the
southwest per 12Z HREF mean. In addition, max 24 hour max HREF QPF
ending at 12Z Fri (8 AM EDT Fri) are near the 5 inch with this
being a reasonable worst case scenario. With some potential for
excessive rainfall, marginal to slight risks for excessive
rainfall have been posted across the southern half of the CWA for
Thursday into Thursday night. The potential for locally heavy rain
continues to be mentioned in the HWO.
With the shortwave brining abundant cloud cover and convection to
the area on Thu, temperatures will be suppressed with highs
generally in the mid to upper 70s anticipated. Lows the next
couple of nights will be typical for August ranging in the 60s
with higher dewpoints in place compared to recent nights. Where
breaks in the clouds occur, river and deeper valley fog should
also form both tonight and on Thu night.
.LONG TERM...(Friday through Wednesday)
Issued at 320 PM EDT WED AUG 2 2023
Key Points:
* Remaining on the cooler side of average Friday, with
shower/storm chances decreasing from north to south through
Saturday.
* An approaching disturbance and frontal boundary bring the return
of scattered to likely (40-60% chance) showers/storms Sunday
afternoon through Monday.
* Scattered showers/thunderstorms (30-40% chance) remain possible
Tuesday and Wednesday, with chances peaking in the afternoon
and evening hours.
An active start to the extended period, as guidance suggests a
remnant MCS will be working across the region into Friday morning.
Given the complexities of the finer scale details, large-scale
guidance is struggling to pinpoint the timing/placement of the
complex at period`s start, but CAM`s largely agree it will be south
of the area. As such, have lowered PoPs from the Blend, limiting the
highest chances to the south/southeast in the likely (60-70%)
category. Aloft, a shortwave trough will be marching through the
Tennessee Valley through the morning, followed by a surface cold
front associated with an Eastern Canadian low aligned across the
Great Lakes to Ohio Valley. This will slide southeast through the
day, with expectations of this stalling out just south of the area
as upper level shortwave ridging glides across the Ohio Valley into
Saturday. With the brief height rises and a surface high across the
Great Lakes, PoPs through the start of the weekend will be limited,
with the highest chances (30%) nearer to the boundary along the
border of Tennessee Saturday afternoon/evening.
The broad ridging across the Southern Plains is then expected to
retrograde westward into the Southwest through the weekend, setting
up more quasi-zonal (west to east) flow through the end of the
period. A series of passing vorts through the flow will keep PoPs in
the forecast each day, with the most notable chances Sunday into
Monday with a deepening wave meandering in from the Northern Plains.
Taking on cyclogenesis, a surface low will take shape into the
Midwest, drawing a cold front east early into the upcoming work
week. As the Great Lakes high marches toward New England, return
flow moisture advection will pump PWATs into the 1.75-2" mark and
scattered to numerous showers/storms will be possible Sunday
afternoon through Monday evening. Though there are some differences
in guidance on the temporal and spatial scale, global runs agree on
the synoptic setup, and thus, have stayed close to the NBM`s
solution. A few strong storms with gusty winds can`t be ruled out
during the peak heating hours of the two days. Thereafter, the
boundary will slowly sink southward, were subsequent mid-level
impulses will keep the threat of scattered (30-40%) PoPs in the
forecast Tuesday and Wednesday, with the highest chances during the
afternoon to evening hours each day.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 730 PM EDT WED AUG 2 2023
VFR conditions will prevail across all TAF sites but only for the
next couple of hours. As a surface low approaches the area,
increasing shower and thunderstorm activity is expected. CIGS
lowering to MVFR around 06Z and then to IFR by 12Z is forecast.
Showers and thunderstorms will increase in coverage from south to
north with VCSH appearing in the TAF at KLOZ and KSME around 06Z.
From then, -SHRA and VCTS is expected through the remainder of the
period at all TAF sites through the remainder of the period.
Showers and fog may cause decreased VIS through the period as
well.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...VORST
SHORT TERM...JP
LONG TERM...BB
AVIATION...VORST
Area Forecast Discussion
National Weather Service Memphis TN
1013 PM CDT Wed Aug 2 2023
...New UPDATE...
.UPDATE...
Issued at 951 PM CDT Wed Aug 2 2023
A warm night is expected for the Mid-South as an upper level
ridge remains parked over the ArkLaTex. 10PM surface observations
show temperatures ranging from the upper 70s to upper 80s across
the region. Therefore, expect overnight to be warm with lows only
dropping to the mid and upper 70s.
Another hot day in expected Thursday as temperatures soar to the
upper 90s and low 100s. By midday, heat index values are forecast
to be at and above 110F for areas along and west of the
Mississippi River. As such, an Excessive Heat Warning and Heat
Advisory are in place for these areas. Limit time outdoors
Thursday and ensure you have enough water and a place to cool off.
In addition to heat, there is a Marginal Risk for severe weather
Thursday. 00Z CAMs depict showers and storms impacting the
northeast portions of the region by sunrise. Overall, forecast
soundings show lack- luster SBCAPE and lapse rates. However, 30-40
kts of bulk shear will likely be present by morning. Therefore, a
damaging wind threat exists for areas along the Tennessee River
through the early afternoon hours.
ANS
&&
.SYNOPSIS...Issued at 226 PM CDT Wed Aug 2 2023
Hot temperatures will remain the biggest weather headline for the
remainder of the work week although we could see another round of
thunderstorms late tonight into early tomorrow. Heat advisories
and excessive heat warnings have been issued for much of the
Midsouth with the hottest temperatures expected in the
Mississippi Delta south of Memphis. Heat indices between 105 and
113 are expected across much of the region. The weekend should be
slightly cooler but still in the 90s. Much of the Midsouth is
expected to remain below 90 degrees early next week.
&&
.DISCUSSION...
(This evening through next Tuesday)
Issued at 226 PM CDT Wed Aug 2 2023
Hot temperatures will remain with us tomorrow and Friday. A warm
front is moving to the northeast across the Midsouth and will lift
north of the area late tonight or early tomorrow opening the path
for Gulf Moisture to return to the region. Dew points in the
middle to upper 70s and temperatures approaching 100 degrees will
result in afternoon heat indices between 105 and 115 across much
of the Midsouth. Another excessive heat warning and heat advisory
has already been issued for tomorrow and will likely be required
Friday.
A ridge over the Southern Plains will shift a bit farther east
tonight into early tomorrow. As a result, the storm track should
shift a bit farther to the east. This is in line with the latest
HRRR runs, taking an MCS associated with a shortwave trough across
eastern Missouri, across west Kentucky and eventually into Middle
Tennessee late tonight into Thursday. Bulk shear associated with
a nocturnal jet may approach 50kt late tonight into early Thursday
generally from the Missouri Bootheel into northwest Tennessee. A
few strong and perhaps severe thunderstorms will be possible,
featuring damaging wind as the greatest threat. However, limited
instability should help curb the severe threat somewhat.
The ridge will begin to break down and retreat back over the
Plains over the weekend resulting in slightly cooler temperatures,
but still in the 90s. A cold front is expected to usher a cooler
and drier airmass back across the Midsouth early next week. Much
of the region may remain below 90 degrees Monday and Tuesday.
30/Sirmon
&&
.AVIATION...
(00Z TAFS)
Issued at 613 PM CDT Wed Aug 2 2023
VFR conditions with SW flow is anticipated overnight. Winds will
be slightly elevated overnight, between 8-11kts. An MCS will push
southeast in the early morning hours mainly affecting MKL. MVFR
conditions could be possible, but CIGS do not look to be lower
than 20,000 ft AGL. As the MCS continues its track, TUP may be
affected as well. The back side of the MCS may initiate some
convection at JBR and MEM in the next TAF cycle.
DNM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Excessive Heat Warning from 11 AM to 8 PM CDT Thursday for
ARZ009-018-026>028-035-036-048-049-058.
MO...Excessive Heat Warning from 11 AM to 8 PM CDT Thursday for
MOZ113-115.
MS...Excessive Heat Warning from 11 AM to 8 PM CDT Thursday for
MSZ001-007-008-010>012-020.
Heat Advisory from 11 AM to 8 PM CDT Thursday for MSZ002-013-021-
022.
TN...Excessive Heat Warning from 11 AM to 8 PM CDT Thursday for
TNZ048-049-088.
Heat Advisory from 11 AM to 8 PM CDT Thursday for TNZ001-019-050-
051-089.
&&
$$
PUBLIC FORECAST...JDS
AVIATION...DNM
Area Forecast Discussion
National Weather Service Nashville TN
907 PM CDT Wed Aug 2 2023
...New UPDATE...
.UPDATE...
Issued at 850 PM CDT Wed Aug 2 2023
Latest radar imagery this evening shows a few sprinkles over our
eastern counties, but overall it`s a quiet evening. Dewpoints
have risen considerably and are currently in the upper 60s to low
70s areawide, and our PWAT has risen nearly an inch from this
morning to 1.78 inches per the 00Z OHX sounding. Regional radar
imagery shows a thunderstorm complex over central Missouri heading
southeastward towards us, and WPC internal discussions plus
latest HRRR model runs indicate this activity is further west than
previous model runs suggested. Therefore, the axis of heaviest
rain across Middle Tennessee should also be further west, with
HRRR showing the heaviest rain and storms overnight and Thursday
along and west of I-24 - not east as previously thought. Went
ahead and increased pops over our west for tonight/tomorrow
accordingly. Rainfall amounts through Thursday afternoon still
look to be 0.5 to 3 inches for most of the cwa, but again with the
heaviest further west.
Other issue is the potential for severe storms tomorrow, mainly
afternoon/evening. Forecast soundings in our southwestern
counties show unusually strong low level shear for August along
with ample CAPE, which would potentially bring a threat for
damaging winds, hail, and even a tornado or two. Main uncertainty
is whether the airmass can recover as much as the forecast
soundings indicate after the morning rain/storms. Would not be
surprised at SPC upgrading our southwest counties to a slight risk
with their overnight update based on this potential.
&&
.SHORT TERM...
(This afternoon through Thursday Night)
Issued at 220 PM CDT Wed Aug 2 2023
After a few days of quiet wx, we are going to shift very quickly
into an active pattern. Concerns through the next 24 hours include
heavy rainfall (local flooding) and possible severe storms.
This afternoon, showers and a few storms coming down from western
KY have weakened considerably while moving our way. This has
resulted in just a few very light showers in our area, mostly non-
measurable sprinkles. Mid afternoon temperatures were in the
upper 70s to mid 80s. The 70s were noted mostly across the Plateau
and the mostly cloudy northern half of the area. Temps were
mostly mid 80s across the sunnier south half.
Much of tonight will be quiet, but chances for showers and storms
will develop late in the night. Activity will really blossom in
coverage and intensity toward daybreak across our northwest
counties, then spread over much of Middle Tennessee Thursday
morning. A disturbance will come down from the northwest as strong
low level warm and moist advection develops ahead of it. Heavy
downpours are expected. Rainfall amounts through Thursday morning
are likely to reach 1 to 2 inches for areas along and northeast
of I-24. Some pockets over 3 inches will be possible. At this
time, we are not going to issue a Flood Watch. We have had several
dry days, and it looks like the heaviest pockets of rain will be
localized and transient. Some spots may have brief local flooding,
but we are not seeing a widespread threat for now.
Going into Thursday midday and afternoon, our concern transitions
from heavy rain to the potential for severe thunderstorms.
Seasonally strong mid level winds, favorable shear profiles, and
capes over 2500 J/kg will come together for severe storm
potential. SPC currently has the area under a marginal risk, but
a bump up for some parts of the area would not be shocking,
particularly our southwest counties where instability will be
strongest. Damaging winds will be the main concern, but if things
line up "just so" a brief tornado could occur. Development of
severe wx will be greatly dependent on how quickly the morning
storms move out and how much heating/destabilization occurs. It
looks like a differential heating boundary will form, separating
the rain-cooled air associated with the morning storms from the
relatively less active, more unstable air to the southwest. This
will be the zone to watch for storm initiation. The details will
come down to the wire as the stronger shear values will be moving
out as greater instability develops through the afternoon.
Scattered showers and storms will be possible Thursday night,
especially late night as another wave comes our way. Some pockets
of heavy rainfall will again be possible. Depending on what
happens Thursday morning, some flood concerns may develop late
Thursday night.
&&
.LONG TERM...
(Friday through next Wednesday)
Issued at 220 PM CDT Wed Aug 2 2023
A warm, humid, and unsettled weekend is ahead. There will be
several weak waves interacting with the steamy air mass to produce
scattered showers and thunderstorms at times. This does not mean
a total washout this weekend as there will be rain-free times.
But, when thunderstorms do form, they could be strong to
marginally severe with very heavy downpours and frequent
lightning. We cannot offer much detail about the timing of
weekend storms at this point, but generally the highest chances
will occur in the heat of the late afternoon and early evening
hours each day. In addition to the concern for storms, weekend
events will be impacted by potentially dangerous heat. Heat index
values will exceed 100 for most of the area Saturday and Sunday,
and there will be pockets of 105+ heat index readings. Please
prepare accordingly for heat and thunderstorms this weekend.
Some relief will come early next week with arrival of a front.
Temps and humidity levels will back off a bit starting Monday,
although scattered shower and thunderstorm chances will continue.
&&
.AVIATION...
(00Z TAFS)
Issued at 609 PM CDT Wed Aug 2 2023
Very light showers are currently ongoing across the eastern half
of the area although ceilings and visibilities remain VFR. These
showers will gradually diminish over the next couple of hours, but
conditions will deteriorate areawide after 06Z. Showers will move
into the area again overnight with the heaviest showers and a few
embedded thunderstorms likely beginning by 10Z to 11Z. Ceilings
and visibilities will drop to MVFR to IFR through the morning.
Improvement is possible after 19Z for most as the heaviest rain
moves out of the area. The exception will be near and across the
Cumberland Plateau (including at KCSV and KSRB) where IFR
conditions will prevail through at least the remainder of this TAF
period and likely beyond.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 71 85 73 90 / 70 100 70 60
Clarksville 70 87 73 91 / 80 100 70 50
Crossville 66 75 66 81 / 70 100 80 80
Columbia 71 87 72 91 / 50 100 60 60
Cookeville 68 78 69 83 / 70 100 80 70
Jamestown 67 75 68 81 / 70 100 80 80
Lawrenceburg 70 86 72 88 / 40 100 60 60
Murfreesboro 70 85 72 91 / 60 100 70 70
Waverly 70 88 72 90 / 60 100 60 50
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Shamburger
SHORT TERM...13
LONG TERM....13
AVIATION.....Clements
Area Forecast Discussion
National Weather Service Pittsburgh PA
1051 PM EDT Wed Aug 2 2023
.SYNOPSIS...
The area remains dry through much of Thursday. Shower and storm
chances return late Thursday into Friday and again early next
week as we shift back into an unsettled weather pattern.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EVENING UPDATE..
Minor update to include haze in the forecast with obs sites
beginning to show visibility down around 6 miles due to the
increase in boundary layer smoke. Extended haze mention through
Thursday for locations where the HRRR forecasts >= 8 μg/m^3
(micrograms per cubic meter), which seems to be where we have
been starting to see reductions in visibility the past couple
instances where we were dealing with wildfire smoke.
No other changes were needed. Previous discussion follows..
PREVIOUS DISCUSSION.
Quiet, dry weather continues through tonight as we remain under
the influences of deep-layer northwesterly flow and surface
high pressure. Low temps trend a little warmer than recent
nights given a gradual return of low-level moisture. Most will
see temps in the upper 50s to low 60s around sunrise.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
A weak shortwave embedded in the northwesterly flow aloft pushes
through the Tennessee Valley on Thursday. This feature will
support a large complex of showers and thunderstorms to the
south and southwest of our area, over portions of Kentucky,
Tennessee, and West Virginia. However, there is some signal in
convective-allowing model guidance that a weak boundary enters
our are from the south late Thursday afternoon, with a plume of
deeper moisture to its south and drier air to its north. At the
same time, a weak lake breeze is expected to develop and push
into our area from the northwest. These boundaries could serve
as foci for isolated to widely- scattered convective initiation
during afternoon and evening hours on Thursday. Opted to keep
low-end precip chances (20%) for much of the area to reflect
this potential beginning at 18Z.
Another upper shortwave, this one initiating farther north over
the upper Great Lakes, rotates southeast Thursday night into
Friday over the local area. This disturbance will provide a bit
more synoptic support for shower and thunderstorm activity,
with greatest concentration over the higher terrain to the
east. This wave then continues east of our are and serves as
the driving mechanism in ejecting the parent upper low that has
been sitting over eastern Canad out over the western Atlantic,
which finally transitions the deep-layer flow over our area
from northwesterly to more zonal.
Temperatures warm slightly through the short term, reaching the
mid 80s each afternoon (upper 70s to low 80s in the mountains)
and only getting down into the mid 60s each night (upper 50s to
low 60s in the mountains).
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
TLDR Version...We dry out briefly over the weekend, but a low
pressure system will bring showers and thunderstorms to the
local area sometime Sunday night through Tuesday of next week,
with exact timing and coverage remaining uncertain at this time.
Full Discussion...We dry out again Saturday as surface high
pressure builds back into the area from the west. Afternoon
highs hold steady in the low to mid 80s and overnight lows
Saturday night range from upper 50s in the higher terrain to mid
60s everywhere else. Global models are in agreement that a low
pressure system forms over northern IL on Sunday, but they
differ with respect to how that system evolves. The GFS remains
the faster and weaker solution, advancing a 999mb low quickly
into Ontario and then the Northeast CONUS by Monday morning and
Tuesday morning, respectively. The ECMWF presents a
significantly slower and more intense progression with a still-
deepening, sub-995mb low crawling northeast into Ontario on
Tuesday morning. Both model solutions bring chances for showers
and storms to the local area, but the exact timing and coverage
will ultimately depend on the intensity and track of the low.
Will need to continue monitoring trends in model guidance and
narrow down the details as we get closer.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Little change to the discussion was needed besides the
elimination past elements. The forecast remains on track.
.. Previous Discussion ..
Hi-res smoke models indicate this should lift north and
eastwards overnight, and further impact to visibilities is not
anticipated.
Patchy river valley fog will be possible once again during the
pre-dawn hours Thursday, favoring HLG/FKL/DUJ with strong
radiational cooling. Otherwise, high pressure exiting to the
east will maintain general VFR through the period.
Confidence in afternoon thunderstorms on Thursday remains low,
but the highest probability is across southwestern portions of
the area, primarily in the MGW region. CAMs continue to show
isolated convection after around 21z. Given this, felt
PROB30-TSRA was appropriate for MGW. Confidence remains too low
to include mention elsewhere.
.OUTLOOK...
General VFR will continue until weak cold frontal passage and
associated showers/thunderstorms on Friday. The next chance for
widespread restrictions and rain will be late Sunday or early
next week with approaching low pressure.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...Cermak
NEAR TERM...Cermak/88
SHORT TERM...Cermak
LONG TERM...Cermak
AVIATION...Rackley/Milcarek
Area Forecast Discussion
National Weather Service Springfield MO
541 PM CDT Wed Aug 2 2023
Key Messages:
1. Flood watch tonight for our northeastern portion of the CWA.
2. Excessive Heat Warning and Heat Advisory have been extended
through Thursday and extended slightly northeastward.
3. Pattern change this weekend will start to bring temperatures
back into the 80s for Sunday through next week.
.SHORT TERM...(This evening through Thursday)
Issued at 121 PM CDT Wed Aug 2 2023
A few showers were occurring over east central Kansas into west
central MO early this afternoon. Temperatures were ranging from
the low 80s in the northeast to the upper 90s in the southwest.
Upper level ridge axis remains in place over the area with a
baroclinic zone stretching north to south over western Missouri.
Remnant convection from the mornings MCS has exited the area to
the east. CAMS redevelop strong to possibly severe convection late
this afternoon or early evening over central Missouri as the low
level jet begins to ramp back up. Heaviest precipitation tracks
northeast of the area, but some of the models do have some
convection in our northeast CWA, which had quite a bit of rainfall
2 nights ago. So, we are maintaining our flood watch and will be
starting this watch a bit earlier that previously issued. It will
now start at 7 pm this evening. PW values still over 2" so very
high efficiency in the rainfall. In addition to the heavy rain and
flood potential, there will be quite a bit of shear over the
central MO counties for a severe weather potential. Large hail,
damaging wind the main risk, with a small risk of a tornado.
This convection should end on Thursday. We have decided to extend
the heat products out through Thursday for all but our northeast
1/3 of the CWA which should be cooler from the clouds/morning
precipitation. HREF probabilities show a pretty good signal for
including the remaining counties in an advisory or warning, with
the warning in the far west.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 121 PM CDT Wed Aug 2 2023
The ridge will begin to flatten out on Friday, but it looks like
hot temperatures will continue at least through Saturday. A
frontal boundary then should push through on Sunday with northwest
flow and a shortwave moving through the area early next week. This
should help to usher in a cooler and drier air mass to the area
and bring next weeks temperatures back into the 80s.
There will be a chance of showers and thunderstorms on a daily
basis as the upper pattern does remain active, but chances at this
time remain in the 20-40 percent range.
The 8 to 14 day outlook which goes through mid August calls for
equal chances of above and below normal temperatures and above
normal precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 521 PM CDT Wed Aug 2 2023
Currently a stalled front extends across west central and central
Missouri then bends southward into south central Missouri. Storms
are expected to develop along and north of the boundary this
evening and into the overnight hours as a low level jet moves
over the MO Ozarks and feeds into the storm complex. For now we
plan to keep storms out of the TAFS but will need to monitor KSGF
and KBBG for updates if the storms spread further south on outflow
boundaries.
Winds will remain southerly at the southwest Missouri airports
through much of the 00Z TAF cycle, but will add a temporary shift
to the north between 12-15Z to account for the outflow.
Low level wind shear will be included after 04Z as the low level
jet returns with the latest HRRR showing 925 mb winds from the
southwest at 40-45 kts. These winds will mix down to the surface
by around 15-16Z with gusty gusts up to 25 kts from the southwest.
VFR clouds/visibility are expected through the forecast period.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...Excessive Heat Warning until 8 PM CDT this evening for MOZ066-
077-088-093-101.
Excessive Heat Warning from 1 PM to 10 PM CDT Thursday for
MOZ066-077-088-093-101.
Heat Advisory until 8 PM CDT this evening for MOZ055-056-067>069-
078>080-089>091-094>096-102>105.
Flood Watch through Thursday morning for MOZ057-058-070-071-083.
Heat Advisory from 1 PM to 10 PM CDT Thursday for MOZ078>080-
089>092-094>097-102>106.
KS...Excessive Heat Warning until 8 PM CDT this evening for KSZ073-
097-101.
Excessive Heat Warning from 1 PM to 10 PM CDT Thursday for
KSZ073-097-101.
&&
$$
SHORT TERM...Lindenberg
LONG TERM...Lindenberg
AVIATION...Terry