Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/12/23
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
1000 PM MDT Fri Aug 11 2023
...New UPDATE...
.UPDATE...
Issued at 958 PM MDT Fri Aug 11 2023
Minor update to the forecast package to lower precipitation
chances tonight into Saturday morning. Still left in slight to
chance PoPs mainly across western and central swaths of the
forecast area where a weak mid-level disturbance moving north
embedded within the monsoon plume will try to produce a few
showers overnight. Updated zone forecast is out.
&&
.SYNOPSIS...
Issued at 240 PM MDT Fri Aug 11 2023
A surge of Pacific moisture will bring scattered to
numerous showers and storms to the region the next several days. The
bulk of activity today and tomorrow will be focused over western New
Mexico before spreading to central and eastern New Mexico Sunday and
Monday. Locally heavy rainfall will increase the risk of flash
flooding over recent burn scars and may create rises on streams and
arroyos. With the increased moisture and cloud cover, temperatures
will be near to slightly below average the next few days then trend
warmer late next week.
&&
.SHORT TERM...
(This evening through Saturday night)
Issued at 240 PM MDT Fri Aug 11 2023
The latest water vapor satellite imagery shows a Monsoon moisture
plume standing up across NM and eastern AZ, with a Pacific low
over/near SoCal and the upper high along the TX coast. 12Z upper air
soundings from AZ and NM were near the 90th percentile of daily
norms for PWATs, so plenty of moisture for mid August to fuel
showers and storms with a locally heavy rainfall threat going
forward. Today`s crop of convection has been fairly limited so far,
but the McBride burn scar near Ruidoso did pick up around 0.30" and
storms are on a slow uptrend across south central and western NM in
terms of both coverage and intensity. The latest HRRR and HREF show
most of the convection late this afternoon and evening continuing
across west central NM, in the higher PWAT airmass. Moisture
advection will continue overnight, setting the stage for a more
active day Saturday with a locally heavy rainfall threat across
western NM, the northern mountains and northeast NM. The threat for
burn scar flash flooding will trend up Saturday for the Cerro Pelado
and HPCC, especially given storm motion considerations. That is,
slow and erratic motion over the Cerro Pelado scar and toward the
northeast for the HPCC, which may lead to training of storms there.
A Flash Flood Watch may be required for those scars. High
temperatures will trend down some Saturday due to the additional
cloud cover and rain-cooling of the lower boundary layer. Convection
is modeled to continue into Saturday night across far northeast NM,
where storms may congeal or organize and produce locally heavy
rainfall.
&&
.LONG TERM...
(Sunday through Thursday)
Issued at 240 PM MDT Fri Aug 11 2023
The state will remain squished between High pressure to the east and
Low pressure to the west on Sunday, allowing Pacific moisture to be
advected in from the south. Guidance has trended down somewhat on
Sunday PoPs, but at least scattered showers and storms are likely
given PWATS 100-140% of normal. Vigorous convection in the
southern plains will drive a frontal boundary westward over the
central mountain chain and into western NM. Confidence is
increasing that gusty east winds will occur in the gaps of the
central mountain chain late Sunday night through Monday. While
moisture will increase behind the front, the lack of instability
will likely limit convection and therefore flash flooding concerns
to some extent on Monday. However, lifting along the boundary
will likely generate large swaths of stratiform precipitation with
light to moderate rainfall rates through Monday night.
The high over Texas will build northwestward Tuesday and Wednesday,
resulting in a downtrend in PoPs despite the near to slightly above
average PWATs. Without Pacific moisture streaming into the region,
cloud cover will be on the decline as temperatures begin to heat up
again. While there is considerable model uncertainty late next
week, there are some indications that the ridge will begin to
shift back east towards the TX/OK panhandles late week. This would
allow deep, Pacific moisture to return to western NM and spark
scattered to numerous afternoon showers and storms.
&&
.AVIATION...
(00Z TAFS)
Issued at 523 PM MDT Fri Aug 11 2023
Scattered convection continues moving nwd over western NM,
bringing localized MVFR and gusty winds from KGNT to KGUP. This
will likely reach nwd up to KFMN b/w 01Z to 04Z. A few outflow
gusts will hit isold spots of the eastern plains south of I-40 as
well. Convection tapers off through the evening, lingering in some
western spots to or just past midnight. More numerous to
widespread shras and ts will develop along the western and central
high terrain Saturday afternoon with convection spreading through
northeastern NM late day.
&&
.FIRE WEATHER...
Issued at 240 PM MDT Fri Aug 11 2023
A Monsoon moisture plume is standing up over the area and will fuel
rounds of wetting storms through the weekend with a burn scar flash
flood threat. A backdoor front will race southwest across the area
Sunday night and focus wetting storms across western NM going into
Monday. The upper high to the east is forecast to build back over
the region going into the mid/late next week, bringing a slow
warming/drying trend. However, sufficient moisture will remain to
produce good chances for wetting storms, mainly in the mountains and
nearby highlands.
&&
.PRELIMINARY POINT TEMPS/POPS...
Farmington...................... 60 87 60 89 / 30 30 20 10
Dulce........................... 51 83 50 85 / 40 50 40 40
Cuba............................ 56 80 56 83 / 30 50 40 30
Gallup.......................... 56 82 55 82 / 60 50 30 30
El Morro........................ 54 78 53 78 / 70 70 50 40
Grants.......................... 55 81 54 82 / 50 60 30 40
Quemado......................... 55 78 54 79 / 70 70 50 50
Magdalena....................... 60 80 59 81 / 60 70 30 50
Datil........................... 55 75 55 77 / 60 70 30 50
Reserve......................... 56 83 53 83 / 50 70 40 50
Glenwood........................ 64 88 63 89 / 50 60 30 50
Chama........................... 48 77 47 78 / 30 70 50 60
Los Alamos...................... 62 81 61 82 / 20 70 50 50
Pecos........................... 61 82 58 83 / 20 60 50 40
Cerro/Questa.................... 48 78 45 79 / 40 70 50 70
Red River....................... 48 72 44 72 / 40 70 50 70
Angel Fire...................... 43 74 42 73 / 30 70 60 60
Taos............................ 52 81 51 83 / 20 60 40 50
Mora............................ 58 79 52 79 / 20 70 60 60
Espanola........................ 61 88 60 88 / 20 50 40 30
Santa Fe........................ 63 82 61 83 / 20 50 40 40
Santa Fe Airport................ 61 85 59 86 / 20 50 40 30
Albuquerque Foothills........... 65 87 67 89 / 30 40 30 20
Albuquerque Heights............. 67 88 66 90 / 30 30 30 20
Albuquerque Valley.............. 64 90 65 92 / 30 30 30 20
Albuquerque West Mesa........... 68 88 66 91 / 30 30 30 20
Belen........................... 63 90 64 92 / 30 40 30 20
Bernalillo...................... 66 90 65 92 / 30 40 30 20
Bosque Farms.................... 62 89 63 92 / 30 40 30 20
Corrales........................ 67 89 65 92 / 30 30 30 20
Los Lunas....................... 61 90 64 92 / 30 40 30 20
Placitas........................ 66 87 65 89 / 30 40 40 20
Rio Rancho...................... 68 88 65 91 / 30 30 30 20
Socorro......................... 63 90 65 91 / 40 50 20 30
Sandia Park/Cedar Crest......... 61 81 60 83 / 30 50 40 30
Tijeras......................... 62 83 62 85 / 30 50 40 30
Edgewood........................ 60 85 58 86 / 40 60 40 30
Moriarty/Estancia............... 59 86 55 87 / 40 50 30 30
Clines Corners.................. 58 83 57 84 / 20 40 30 30
Mountainair..................... 59 83 58 85 / 50 50 30 30
Gran Quivira.................... 59 84 59 85 / 50 40 30 40
Carrizozo....................... 65 87 65 89 / 40 30 30 40
Ruidoso......................... 60 80 59 81 / 30 50 30 60
Capulin......................... 58 78 55 80 / 30 60 60 50
Raton........................... 56 82 55 83 / 30 70 60 50
Springer........................ 59 86 57 86 / 30 70 60 40
Las Vegas....................... 59 84 56 84 / 20 60 50 40
Clayton......................... 67 87 61 89 / 30 60 60 30
Roy............................. 64 86 59 87 / 20 60 60 50
Conchas......................... 68 96 65 95 / 20 40 60 40
Santa Rosa...................... 68 93 64 92 / 20 40 60 40
Tucumcari....................... 66 96 65 95 / 20 30 50 30
Clovis.......................... 67 97 67 96 / 20 30 40 20
Portales........................ 71 99 68 98 / 20 20 40 20
Fort Sumner..................... 71 97 67 96 / 20 20 50 20
Roswell......................... 77 102 73 101 / 20 20 20 20
Picacho......................... 69 92 66 91 / 20 40 20 50
Elk............................. 65 88 62 88 / 20 40 20 50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...11
LONG TERM....16
AVIATION...24
Area Forecast Discussion
National Weather Service Binghamton NY
830 PM EDT Fri Aug 11 2023
.SYNOPSIS...
A front will move through the region Saturday, and is expected
to bring scattered to widespread showers and thunderstorms
Saturday afternoon and through the evening. Brief high pressure
with pleasant weather expected on Sunday before the next system
moves in late on Monday through Tuesday with widespread rain showers.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
8 PM Update...
Quiet weather prevails this evening, with mainly clear skies,
light winds and temperatures in the mid-60s to lower 70s as of 8
PM EDT. Just some scattered high level cirrus clouds are
present, with more clouds expected to spread in from the west
overnight. Before the clouds fully arrive, some patchy valley
fog could form underneath. Watch a complex of thunderstorms
across north-central to NE Ohio currently, steadily marching
east. Most of the CAMs have these storms losing intensity and
falling apart with just some sprinkles or light showers reaching
out western zones in the pre dawn hours tonight. The forecast
for Saturday still remains well on track. Made some minor
adjustments to bring PoPs down in the morning hours (chance to
low end likely over the northern Finger lakes and Syracuse area
now, as opposed to likely and categorical from the previous
forecast). This was based largely on the latest CAMs, especially
the HRRR and 3km NAM showing less activity and keeping it closer
to a warm frontal boundary lifting north during the morning hours.
The setup has not changed for Saturday afternoon, and it still
looks favorable for scattered to numerous severe thunderstorms
to develop as MLCAPE exceeds 1500-2000 J/kg and deep layer shear
hovers around 40-50 kts. DCAPE values are progged to potentially
reach 800-1000 J/kg late in the day and evening, which would aid
in the development of localized damaging winds with these
storms. Large hail would also certainly be possible with at
least a few of these severe storms, as CAPE remains high in the
hail growth zone of the forecast soundings and equilibrium
levels reach nearly 12km up. Forecast soundings do show an
increase in the low level shear (0-1km) potentially reaching
20-25 kts, with SRH values getting toward 200m2/s2...this points
to at least a potential for an isolated tornado or two in the
area. There will be plenty of heat, moisture an instability for
these developing storms to work with as highs are forecast to
reach well into the 80s Saturday afternoon, with dew points in
the mid-60s to lower 70s also expected.
330 PM Update..
High pressure system remains in control this afternoon and into
evening. Conditions are expected to remain dry with northwest
flow up to 10 knots. After sunset winds will become light and
variable. High clouds begin to fill in overnight as the next
system approaches. Cloud cover could keep fog from developing,
but there is still a possibility of seeing some river valley
fog. Lows are expected to fall into the mid 50s to lower 60s
tonight.
A weak short wave is expected to move through Saturday morning
setting off early day warm air advection showers. There is some
potential for storms to develop as conditions destabilize late
morning/early afternoon as a more pronounced short wave is
expected to move through along with a cold front. SPC
Convective Outlook places our area in a slight risk for severe
thunderstorms. SPC also hints at a 15% probability of seeing
hail and damaging wind gusts with this system. Forecast
soundings during peak heating show CAPE values ranging from
1,500 to 2,000 J/kg, with 0-6 km bulk shear ranging from 35-40
knots, and steep mid level lapse rates. Hail parameters appear
borderline, but agreeing with SPC there is still potential to
see hail with some of these thunderstorms. Storm relative
helicity and energy helicity index values suggest isolated
tornadoes are also a possibility. Soundings show the LCL heights
slightly below 1,000m, therefore if any rotation does
materialize, there is potential for that rotation to extend to
the surface. Keeping that in mind SPC only mentions a 2%
probability of a tornado at this time. Highs are expected to
reach the upper 70s to mid 80s in the afternoon.
Despite this, timing of the initial short wave moving through
Saturday morning could affect afternoon instability. If the morning
showers hang around longer than expected, this could hinder surface
heating, and as a result further decrease instability indices.
Another concern for Saturday will be the progression of the
front. Similar to the previously mentioned lingering morning
showers decreasing instability, timing of the frontal passage
will also affect this forecast. As the upper-level trough
continues its eastward progression, some showers and storms may
linger into Saturday night. Once this system makes an exit
sometime Saturday night into Sunday, high pressure will begin to
build in behind it. Lows are expected to fall into the upper
50s to low 60s Saturday night.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
230 PM Update...
Surface high pressure will build into the region on Sunday,
however the upper level trough will remain overhead. Diurnal
showers will be possible with max heating during the afternoon,
mainly along the Catskills, however, any showers will be very
isolated. Temperatures during the day will warm into the upper
70s and lower 80s. High pressure will not hand around along, as
our next system will arrive on Monday. Low pressure will be
moving east across the western Great Lakes Monday morning with
an eastward extending warm front eventually working into the
NY/PA area by the afternoon. A robust plume of moisture and
broad lift in the warm air advective air mass into the warm
front will likely result in a broad area of rain showers with a
few embedded thunderstorms Monday afternoon. Thick cloud cover
should keep temperatures Monday in the mid to upper 70s. The low
will continue pushing eastward Monday night with a trailing cold
front entering western NY by early Tuesday morning. Widespread
rain showers and possibly some embedded thunderstorms will be
possible early Tuesday morning out ahead of the approaching
front.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
235 PM Update...
Cold front will push through the region on Tuesday with more
widespread rain showers and perhaps a few thunderstorms. Behind
the front, upper trough will remain overhead and with cool NW
flow at the surface, a few lake- enhanced rain showers will be
possible into Tuesday night. By mid week, high pressure and
ridging will start taking hold, and a few days of quiet weather
is looking likely Wed - Thu.
Unfortunately, the models are hinting at the pattern remaining
active and another system approaching near the end of the week.
Still quite a bit of timing differences and amplitude of this
next system, which is expected being day 7, so just stuck with
NBM solution at this time due the uncertainty among the
guidance.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
High pressure will slowly slide eastward tonight, keeping
conditions mostly VFR across the area. ELM and BGM may have some
early morning fog but confidence is not high at this time. High
pressure is in place but boundary layer winds are somewhat
strong and the approaching weather system from the west will
bring mid to high level clouds overhead tonight which will limit
fog formation. ELM may be able to eek out a few hours of MVFR
fog this morning and BGM may see another "sunrise surprise" fog
for a few hours. Confidence in this is not high so IFR was left
out of the TAFs.
Saturday will be an active weather day with rain showers and
thunderstorms expected to spread west to east across the area
from late morning through the evening hours. PROB30 for
thunderstorms was included at all terminals where conditions
for thunderstorm development were the greatest. Storms may still
occur before and after these time periods but this TAF set is
too far out to try and lock in the details.
Outlook...
Saturday night...Restrictions due to fog possible.
Sunday and Monday...mainly VFR.
Monday night through Tuesday...restrictions likely in showers
and thunderstorms.
Wednesday...mainly VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...ES
NEAR TERM...ES/MJM
SHORT TERM...MPK
LONG TERM...BJT/MPK
AVIATION...JTC
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
1011 PM CDT Fri Aug 11 2023
.UPDATE...
Issued at 1010 PM CDT Fri Aug 11 2023
Little needing updating this evening. Showers and thunderstorms
have diminished for the most part across the CWA, and only remain
across far northeastern portions across the state. Clouds will go
on a clearing trend through the night. This clearing trend and
less winds could bring about some higher RH values in the north.
This could lead to at least some patchy, perhaps shallow, fog.
Forecast soundings still do not show the greatest setup for fog
with some lingering elevated winds and an overall shallow layer
of moisture. Thus confidence in fog formation is overall low,
although was enough to place in some patchy fog in the forecast
mainly in the north and some portions of the James River Valley.
Otherwise the forecast remains on track.
UPDATE Issued at 645 PM CDT Fri Aug 11 2023
Minimal updates needed at this time. Shower and thunderstorm
activity is mainly in the eastern portion of the state currently.
There still remains some weak instability in the north east and
through much of the James River Valley. Thus an isolated
thunderstorm is still possible this evening, with severe weather
not expected. Otherwise the forecast overall remains on track.
There could be some patchy fog in the north later tonight into
Saturday morning. Soundings indicate it may still be too dry or
perhaps too mixed with lingering westerly winds. For now
confidence was too low to include at this time.
&&
.SHORT TERM...(This Evening through Saturday)
Issued at 315 PM CDT Fri Aug 11 2023
Breezy weather continues this afternoon across the area, with a
few scattered showers and thunderstorms possible from the Turtle
Mountains through the James River Valley into the evening hours.
This afternoon, an upper low was analyzed over central Manitoba,
with very broad troughing extending across most of the CONUS. Weak
high pressure extended across much of Montana into western South
DAkota, while a surface low was placed in southeast North Dakota.
The latest RAP analysis advertises a vort max moving through the
cyclonic flow aloft, with the bulk of this forcing focused just
east of our forecast area in eastern North Dakota and into
northwest Minnesota.
A somewhat agitated cu field continues to develop on the leading
edge of this impulse. A few areas of this cu are beginning to
show radar returns as of 1930 UTC, with lightning observed in
Stutsman and Foster Counties. High- res guidance continues to not
advertise much, with the exception of the NAM Nest, so relying
mainly on satellite trends to determine where to broad brush POPs.
Instability remains limited as expected, generally under 500
J/kg, but that plus steep low level lapse rates is enough to
warrant widely scattered, on and off showers and thunderstorms
through the rest of the afternoon and into the evening hours
across our eastern counties.
As the upper low drifts off to our east tonight, precipitation will
taper off through the evening, and winds will become light and
variable. Overnight lows will generally be in the lower to mid
50s, with some of our typical cool spots dropping into the upper
40s.
.LONG TERM...(Saturday Night through Friday)
Issued at 315 PM CDT Fri Aug 11 2023
The long term period is dominated by a north-northwestern flow
pattern with occasionally strong troughing that will allow for
periods of showers, some of which might be relatively heavy, along
with the potential for thunderstorms. Starting mid-week next week
the uncertainty in pattern placement and timing results in notably
low confidence in temperatures and overall conditions.
We begin the weekend with a relatively quite Saturday, with high
temperatures in the 70s to 80s, decreased winds, and relatively
dry conditions. As we move into Saturday night, however, a
shortwave trough drops in out of Alberta and deepens over ND. This
strong troughing will allow for scattered to numerous showers and
embedded thunderstorms to sweep eastward over North Dakota
through Sunday and early into Monday. As it stands, we have
moderate signals for heavier rain amounts through the central and
eastern portions of our forecast area, with the odds in the 50-60%
range for 0.5" in these regions and especially the southeast.
Chances for higher amounts of rainfall are lower but still
considerable, with the southern James River Valley currently
having a 15% getting up to around 2" of rain with the latest NBM
run. Conditions on Sunday will be noticeably cooler than the
previous week, with highs in the mid 60s east to lower 70s west,
along with gusty winds in the west and south. We lack sufficient
instability for CI, however, so severe weather concerns for this
weekend are very low.
As we move into Monday, conditions again become calm and dry with
daytime temperatures climbing back up the upper 70s and mid 80s into
the middle of the week as an upper level ridge builds in from the
west. Uncertainty develops starting Wednesday as the timing of
shortwave perturbations and the eastward extent of the ridging
pattered is discordant between model members. The potential for
scattered showers and thunderstorms is hinted at most days starting
mid week, but no particular day is strongly signaled at the moment.
While deterministic temperatures keep us around the 80 degree mark,
there is noticeable uncertainty with some areas have a spread of up
to 16 degree later in the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 645 PM CDT Fri Aug 11 2023
VFR conditions are expected through the forecast period. Breezy to
windy conditions from today will diminish this evening, and may
become light and variable tonight. A light northwest to northerly
breeze may then return for Saturday. An isolated shower or
thunderstorm is possible through this evening in the north through
the James River Valley, however confidence is not high enough to
include in the TAFs at this time. Otherwise look for diminishing
clouds tonight into the start of Saturday. Perhaps more clouds
return Saturday evening. Overall VFR and mainly dry conditions
are expected.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Anglin
SHORT TERM...Jones
LONG TERM...Adam
AVIATION...Anglin
Area Forecast Discussion
National Weather Service Corpus Christi TX
647 PM CDT Fri Aug 11 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Saturday night)
Issued at 249 PM CDT Fri Aug 11 2023
Key Messages:
- Heat Advisories and Excessive Heat Warnings in effect this evening
and again for Saturday.
- Elevated to Critical Fire Weather conditions are expected Saturday
afternoon as well.
Thought about the copy/paste meme going around with the forecast
discussions, since there has been little going on with the weather
other than hot, humid, and rain-free. So with that said, the winds
will still be on the breezy side as the going into the evening, and
diminish a bit, before strengthening again Saturday afternoon as the
pressure gradient tightens along the Coastal Bend by the late
morning. Winds will again be 10-20 with gusts to 25-30 by the
afternoon. Farther to the west in the western Brush Country and Rio
Grande Plains wind look to a little stronger, and with the min RH
<30% so expecting Critical fire weather pattern for tomorrow. Heat
indices will be over 115 in a slightly larger area than today as the
some of the humidity expands into the Brush Country. Cotulla is
probably like a 60-70% chance of getting to 115F HI for 2 hours.
Otherwise, there will probably be light fog/haze near Alice and
Victoria with a streamer clouds off the Gulf for the morning,
before clearing out as the sun starts to mix out the moisture.
&&
.LONG TERM...
(Sunday through next Thursday)
Issued at 249 PM CDT Fri Aug 11 2023
Key Messages:
- A medium to high chance of dangerous heat continues next week
Unfortunately, no relief from the abnormal summer heat is in sight
based on the latest ensemble guidance. The 594 dam ridge at 500 hPa
will remain centered over the Gulf Coast through Monday. Ensemble
guidance indicates a trough will dig into the Southeast during
Tuesday and Wednesday of next week and contributing to the ridge
axis shifting over the Southwest. Cyclonic vorticity being advected
along the periphery of the ridge will support a low chance (less
than 20%) for isolated precipitation across the Coastal Bend Tuesday
and Wednesday. Due in part to the potential for showers and cloud
cover, the likelihood of maximum heat index values over 115 degrees
decreases to 10-30% on Tuesday and Wednesday before climbing back to
40% later in the week. There will be a medium to high chance (40-
70%) of Heat Advisories being issued for heat index values exceeding
110 degrees each day next week.
&&
.AVIATION...
(00Z TAFS)
Issued at 647 PM CDT Fri Aug 11 2023
Gusty southeast winds will continue through mid evening for the
coastal plains and into the early overnight period for the western
Brush Country. Southerly low level flow will be from 25-35 knots
during the night. SREF probabilities and latest HRRR show MVFR
ceilings will likely develop over the coastal plains for the
overnight period with even patchy fog at ALI/VCT around daybreak.
Showed TEMPO for MVFR ceilings between 06-14Z over the coastal
plains with MVFR ceilings possible at COT 10-14Z Saturday. Winds
will increase around 14Z with only few to scattered clouds in the
morning. Winds will turn southeast and strengthen with the sea
breeze in the afternoon over the coastal plains.
&&
.MARINE...
Issued at 249 PM CDT Fri Aug 11 2023
SCA winds continue this afternoon into this evening on the
bays and nearshore south of Port Aransas. Winds will diminish
overnight as the pressure gradient slackens. However, as the heat
low to the west begins to deepen the gradient tightens and the SCA
winds are expected again for Saturday, only to diminish Saturday
night. Onshore winds of 10-15 knots and seas of generally 2 feet
or less are expected through next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 82 99 81 98 / 0 0 0 0
Victoria 80 101 78 101 / 0 0 0 10
Laredo 81 109 81 109 / 0 0 0 0
Alice 79 106 77 105 / 0 0 0 0
Rockport 83 95 82 94 / 0 0 10 10
Cotulla 80 108 80 108 / 0 0 0 0
Kingsville 80 104 80 102 / 0 0 0 0
Navy Corpus 83 95 83 92 / 10 0 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory until 8 PM CDT this evening for TXZ229>234-239-240-
245>247-342>344-346-347.
Red Flag Warning from 11 AM to 8 PM CDT Saturday for TXZ229-239-
240.
Excessive Heat Warning from noon to 8 PM CDT Saturday for
TXZ229>231-241>244.
Heat Advisory from noon to 8 PM CDT Saturday for TXZ232>234-239-
240-245>247-342>344-346-347.
Excessive Heat Warning until 8 PM CDT this evening for
TXZ241>244.
GM...Small Craft Advisory until 10 PM CDT this evening for GMZ231-232-
250.
Small Craft Advisory from 11 AM to 10 PM CDT Saturday for GMZ231-
232-250.
&&
$$
SHORT TERM...JSL
LONG TERM....TWH
AVIATION...TMT/89
Area Forecast Discussion
National Weather Service State College PA
1055 PM EDT Fri Aug 11 2023
.SYNOPSIS...
A ridge of high pressure over Central PA will maintain fair and
dry weather for much of the region tonight. A warm front will
bring a return of humidity and an increasing chance for
thunderstorms beginning very late tonight across the Western M
mountains and elsewhere Saturday afternoon through Saturday
evening.
Some of the storms may be strong to severe Saturday afternoon
and evening, especially over the north. Another brief break in
the weather is expected Sunday, as a cold front moves south of
the Keystone state. More showers and storms arrive later Monday
into early Tuesday, ahead of a cold front moves eastward.
&&
.NEAR TERM /UNTIL 8 AM SATURDAY MORNING/...
Sfc high pressure ridge over Central PA was providing mainly
clear skies over the Eastern half of the state. However,
significant changes enter at least the western part of the
region stage left overnight as a quite compact but rather
vigorous mid/upper short wave (embedded in the left exit region
of a lead, 70 kt jetlet) pushes east-southeast over an
advancing warm front. This weather feature and it`s increasingly
strong thermally indirect circulation with sharp upper level
diffluent flow will likely impact our western (esp the Laurels) and
possibly central zones to a much greater than current and the
past several runs of the HRRR and other CAMS guidance have been
indicating. Thus, will increase clouds, POPs and to a lesser
degree - overnight min temps across the western third to half of
the CWA - centered on the 06-10Z Sat period.
This is one of those infrequent cases where MU CAPE will be
increasing overnight as a result of approaching meso-B dynamics
outdoing the typically stabilizing nocturnal llvls.
Overnight lows will be mainly in the low to mid 60s with slowly
increasing sfc dewpoints.
&&
.SHORT TERM /8 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Saturday looks like it`ll display a one-two punch for at least
part of the CWA (Esp across the Susq Valley and points east)
where tonight`s warm front and lead dynamics will spark a
relatively early, initial round of TSRA, followed by a second
and possibly more extensive line of TSRA across the
Western/Central Mtns late Sat afternoon and evening.
Latest 00Z model 0-1 KM EHIs indicate a rather high potential
for rotating updrafts and even a few weak tornadoes across the
NE quadrant of our CWA with values in the 2-3.5 M2/S2 range.
We continue to be less concerned about heavy rain at this
point. If a heavy rain issue does develop, then most likely
it will be later in the day Saturday (or Sat evening) and
across the south, as mid level flow is rather strong across the
north. Main concern is localized enhanced/damaging wet
microbursts from mini bows/bkn-s signatures in line segments,
triggered by descending rear inflow jets.
Any remaining showers should move out by early Sunday.
More detail below.
Some storms could move into the far northwest late tonight,
given the warm advection. These storms will likely weaken
by late morning.
New storms likely to form Saturday afternoon, mainly across the
north with the stronger winds aloft. Also dewpoints likely to
pool near the warm front. Some hints of a low forming over the
middle Susquehanna Valley by early afternoon, which would aid
storm formation in that area. Further south dewpoints forecast
not to be that high, thus the day may remain dry down along the
MD line.
If dewpoints can get into the upper 60s Saturday evening across
the south, then more in the way for some heavy downpours.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Some lingering showers are possible into the early morning
hours on Sunday as the cold front continues progressing
eastward. Drier air behind the front should result in fair and
seasonable weather for most of the area Sunday, salvaging the
second half of the weekend after a stormy Saturday.
Guidance continues to indicate a deepening upstream trough will
approach early next week, with the associated surface low
tracking west of PA through the Eastern Great Lakes Monday
PM/Tuesday AM. The lack of spread among ensemble members
warrants a continuation of higher PoPs Monday PM to coincide
with the best forcing with the low level jet/plume of anomalous
pwats. The severe threat currently looks limited, due to
relatively stable air over PA north of a warm front. Some
uncertainty remains this far out in the forecast cycle,
especially with regards to timing of the shortwave and
associated frontal boundaries, where severe potential would
increase if the warm sector gets into southern PA.
Slightly cooler conditions appear likely next Tuesday
associated with the passage of the upper trough with scattered
showers and thunderstorms, especially across the northwestern
mountains of central PA. Any precipitation will taper off
Wednesday into the first half of Thursday as an anomalously
strong ridge builds over the area. Recent guidance has began to
suggest ridging continuing throughout the evening hours on
Thursday, although some model disagreement continues to exist,
thus have kept SChc/Chc PoPs for the end of the period.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Looking at VFR conditions for this evening and most of the area
overnight. A warm front could bring a thunderstorm to BFD or a
shower to JST/AOO early tomorrow morning.
This area of storms likely to weaken Saturday morning, as they
move east.
The chances for Saturday afternoon thunderstorms increases
towards the end of this TAF period for the northern sites as
severe convection is possible. Southern sites are less likely
to see stronger storms, but that could change as the system
evolves tomorrow.
Outlook...
Sun...Showers possible early, then clearing with VFR conditions.
Mon...Generally VFR, with scattered SHRA/TSRA developing late
across the west and overspreading the remainder of the area
Monday night.
Tue...Lingering -SHRA poss, mainly N/W.
Wed/Thu...Dry weather with VFR conditions.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert/Martin
NEAR TERM...Lambert/Martin
SHORT TERM...Lambert/Martin
LONG TERM...Banghoff/NPB
AVIATION...Martin/Bowen
Area Forecast Discussion
National Weather Service Quad Cities IA IL
920 PM CDT Fri Aug 11 2023
.UPDATE...
Issued at 918 PM CDT Fri Aug 11 2023
The strong to severe storms in the north, offering primarily a
hail threat, look to arrive along Highway 20 by 11 PM.
To the south, SPC is coordinating a SVR watch for mainly MO, and
we`ll be on the northeast edge of that. This again, is mainly a
hail threat (if it actually impacts our counties, vs staying
south).
The northern activity may begin to wane fairly soon, as the
southern complex develops.
ERVIN
&&
.SHORT TERM...(This evening through Saturday)
Issued at 218 PM CDT Fri Aug 11 2023
Key Message:
- Two separate areas of storms are possible tonight, one north of
Highway 20 and one south of Highway 34
Discussion:
As of 1 PM, visible satellite shows mostly clear skies across the
area with a band of sct/bkn cumulus clouds drifting east across the
MS River. Temperatures were in the mid 70s to low 80s, dew points
in upper 60s to mid 70s, and winds WSW at about 10 to 20 MPH with
some gusts to 25 to 30 MPH. Looking at regional radar mosaic,
some scattered storms have developed in SW IA and are tracking
ESE. However, they are diminishing as they approach Interstate 35.
Tonight, isolated to scattered showers and storms are expected to
clip our southern CWA towards evening lasting into the early
morning. This activity would have the potential to be strong to
severe with a wind and hail threat. While the SPC has reduced the
Slight Risk area over much of our area to a Marginal, it maintains a
Slight Risk south of Fairfield, Burlington, and Macomb as well as
north of Independence, Monticello, and Mt Carroll. The expected
storms to our north are expected closer to 11 PM to 1 AM and may
stay north of the CWA entirely as several CAMs runs have depicted.
None-the-less, they will have the potential to be strong to severe
as well, with a predominantly wind threat and to a lesser degree of
a hail threat. Both areas of convection are expected to move east of
the area just before sunrise. Lows will be in the 60s. Mostly clear
skies will prevail tonight otherwise with winds becoming light.
The latest HRRR is now showing some late night development along
I-80. If this trend continues, an increase in POPS may be needed
for the overnight hours.
Saturday, high pressure will work into the area with NW winds and
sunny skies. Highs will be in the mid 80s to near 90.
.LONG TERM...(Saturday night through Friday)
Issued at 218 PM CDT Fri Aug 11 2023
Saturday night and Sunday...Passing sfc ridge with light and
variable sfc wind regime may foster some patchy fog development
Sat night as temps dip into the lower 60s or even some upper 50s
north. On Sunday, most of the day should be dry locally, with the
CWA in between the two main forcing zones...one to the north acrs
MN, far northern IA, and WI near the main short wave/upper low.
The other to the south along a sfc wave and associated warm front
trying to retreat northward acrs KS into MO. High temps Sunday
generally in the mid 80s. Sunday night, likely MCS acrs MO into
the south half of IL may scrape the southern CWA, while a sfc
front gets shunted through the rest of the area from the west by
the wave digging slowly acrs the upper MS RVR Valley. Thus higher
POPs seem warranted, but again the central to northern fcst area
may have limited precip coverage being in-between the more optimum
moisture feed channels and convergent zones. Best chance for
stronger storms may be off to the south on southern half flank of
the boundary MCS.
Monday and Tuesday...Closed cooler core upper low acrs the western
GRT LKS will look to shuttle clouds and wrap-around showers down
acrs portions of the area on Monday. Depending on extent of cloud
cover, temps may be held down in the 70s acrs much of the area in
breezy northwest winds. Monday night lows in the 50s. Continued
below normal temps into Tue in ongoing cool air advection(CAA), but
more sunshine may add a degree or two to the temps that occur on
Monday.
Wednesday thru next Friday...Medium range ensembles suggest another
Pacific NW vigorous wave will look to ride the western CONUS broad
upper ridge and then dig down acrs the upper Midwest/Upper MS RVR
Valley. This system may bring a return flow warming trend ahead of
it by mid next week, as well as shunt another re-enforcing cold
front with precip chances thru the area sometime late Wed or Thu.
The post-frontal cool down into next Friday may not last long, with
longer range signs of a building thermal ridge off to the west acrs
the plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 609 PM CDT Fri Aug 11 2023
Strong thunderstorms clusters will move east/southeast through
MN/WI this evening, and cover far southern Iowa and northern
Missouri. Though nearby to our aviation concerns, both areas are
expected to remain far enough away from terminals to keep the
forecast dry through the passage of a cold front, late tonight.
A VFR forecast remains in place, with a wind switch to northwest
around 10Z. There is a small chance that an isolated storm could
impact a site with the passage of the cold front, and that will be
a brief isolated storm, addressed with more certainty on the 06Z
TAF set.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...Ervin
SHORT TERM...14
LONG TERM...12
AVIATION...Ervin
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
701 PM CDT Fri Aug 11 2023
...Updated 00Z Aviation...
.Discussion...
Issued at 253 PM CDT FRI AUG 11 2023
Key Messages:
- Strong to Severe Storms Late This Afternoon
- Scattered Thunderstorms Early Saturday Morning Central Missouri
- Strong to Severe Storms Possible Sunday into Monday
Discussion:
Previous Update From 110 PM, With Minor Correction:
PV anomaly with prominent trough continues to traverse the Canadian
Prairie Provinces and has prompted multiple short-wave perturbations
across the Central CONUS. A 594dam high at H5 has shifted slightly
eastward across the southern Plains into the Gulf region and has
provided subtle H5 height rises across the region early this
morning. There are two vort maxes associated with separate H5 short-
waves that are driving the active weather from the lower Missouri
River Valley into the Upper Mississippi River Valley. The first is
moving through Central Wisconsin late this morning, and this is
associated with a surface cyclone centered over Minnesota, with cold
front extending southwestward through the Central Plains of Nebraska
and into the High Plains of Kansas. There is another surface cyclone
that spans much of the Texas Panhandle that has been deepening in
response to a mid-level vort max on the backside of the H5 high.
Surface troughing has expanded northeastward toward the Ozarks
Region and eastern Kansas as that cyclone has continued to deepen.
This has been pushing a warm front northeastward this morning,
increasing the strength of the WAA region into the middle
Mississippi River Valley.
Even though the low-level jet kicked in, convection this morning
north of Hwy. 36 was not overly strong, and actually wound up
clearing up quickly as the H5 height rises shifted further north. As
a result, all of eastern Kansas and most of Missouri have see
boundary layer destabilization throughout much of the morning.
Without the cloud cover to the north, differential heating has not
been as strong as could have potentially been, therefore convergence
along the warm front likely will not be nearly as strong as was
indicated yesterday. However, with the continued surface pressure
falls into the afternoon, along with the short-wave trough moving
out of Central Nebraska/Kansas across the area, there will still be
plenty of forcing around later this afternoon, and not expected to
greatly hinder the convection forecast. With the strong insolation,
visible satellite has shown the development of a cumulus field over
northwestern Missouri tied closer to the mid-level vort max. During
the early afternoon, initial cumulus clouds will be battling a
stronger cap. The 12z Topeka RAOB showed a strong inversion layer
from 975mb-875mb. ACARS soundings out of MCI late in the morning
showed this inversion is still present, but boundary layer mixing
has been working to erode to this rapidly. With the approaching vort
max and short-wave trough, deep layer wind has been steadily
increasing. By the afternoon, expecting 0-6km bulk shear values
around 45-50 kts. The HRRR/RAP have simulated extremely mixed
boundary layers reach dry adiabatic lapse rates, and a few points
with shallow super-adiabatic rates. Thinking that the RAP/HRRR are
over exaggerating the mixing, but, still expecting static stability
to drastically weaken in the boundary layer, with mid-level lapse
rates between 7.8 to 8.3 C/km. The combination of deep layer shear
with destabilization through the afternoon will be supportive of
strong updrafts. With the 12z cycle of the CAMs, the HRRR has
delayed convection initiation by about 2 hours, waiting closer to
00z for storms to develop along the MO-KS border. However, HiRes-FV3
and NSSL-WRF still kept initiation closer to 22z and then moved
storms east-southeast. As of 18z, we are already seeing robust
initiation in Kansas and southeast Nebraska. Models have not added
any increased confidence to timing and convective trends. The
overall environment will foster updraft development with peak
diurnal heating. Hazards with convection this afternoon and evening
will be tied to storm mode. With in the first 2-3 hours of CI, a
discrete supercell storm mode will be supported, especially along
the warm front. The hodographs will continue to lengthen as the mid-
level vort max propagates eastward. Between 19z-00z, the hodograph
for the most part will be straight. For storms moving with the mean
wind, most of the vorticity will be crosswise, which will still
support supercell structure and mid-level rotation. Closer to the
surface though, flow has remained weak despite the surface pressure
troughing over the past 12 hours. During the late afternoon and
around time of CI, the low-level hodograph is not progged to
demonstrate much curvature. Therefore, this increases the difficulty
for low-level mesocyclone organization. The combination of weaker
low-level shear, while 2-6km shear is stronger combined with robust
thermodynamics, supercells will be capable of producing large hail.
With higher LCLs, theta-e deficits from the surface to the top of
the convective boundary layer will be large along with DCAPE between
1000-1500 J/kg. Therefore, strong downdrafts with robust cold pools
will be capable of also producing damaging winds, and may promote
RFD surges if supercell storm mode is realized. The tornado threat
remains very limited by two main factors. The first, is that surface
and mixed-layer based parcels have LCLs between 1100-1200m.
Secondly, during the period of discrete convection, the lack of
curvature in the lowest 0-500m and 0-1km will result in mostly low-
level crosswise vorticity also hindering tornadogenesis. If a
supercell remains close to the warm front, it may be possible for
surface winds to back in the area of surface pressure falls which
could increase low-level SRH, and if we get enough stretching could
try to produce a tornado. But overall, there are multiple factors
going against the tornado potential. The last several runs of the
HRRR, as well as other members of the HREF have depicted a few
updraft helicity (UH) tracks, and these have been focused mainly
along the warm front. One thing that seems to have changed from last
night is the warm front surging northward, likely because there is
not much clouds in the north. The HRRR seems to be focusing
additional convection along the warm front, and moving more along
the Hwy. 36. Along this boundary, this is where portions of the 3-
6km hodograph are developing backing profile between 22z-00z in
RAP/HRRR soundings, which if we see a left-mover could promote large
hail development in those storms. (Previous discussion said
veering in 3-6 km, it is actually backing. The low-levels may
veer, resulting in a veer-back hodograph). Recent runs of the HRRR
do not develop any convection in the ambient warm- sector.
However, if mixing continues to erode the cap, we could see more
development in the warm sector. However, development remains
uncertain there, and the early initiation in southeast Nebraska
has complicated matters more on how the warm front will behave,
and might it stop surging northward. Eventually, by this evening,
a low-level jet kicks in. This will start to increase curvature in
the lowest portion of the hodograph, and in theory would increase
streamwise vorticity. However, with this low-level jet would
expect storms to congeal and no longer be a discrete mode.
Therefore, the threat transitions more to winds with a low- static
stability in the boundary layer and DCAPE values that remain
above 1000 J/kg. Strong cold pools can still support damaging
winds. Areas along the warm front will support the best
development, but we do not want to rule out additional development
in the warm sector, especially if we see isentropic ascent with
WAA in the south or stronger convergence along the low- level jet.
New Section Generated at 258PM:
Saturday Early Morning:
CAMs have been simulating additional convection along Interstate 70
and southward, east of Hwy. 65 for the early morning hours of
Saturday. This appears to be initiating on the nose of the
developing low-level jet over the warm sector. Given that convection
has not been handled well Friday afternoon and evening, it is hard
to be able to rely on these CAMs, given that earlier convection
could change the position of the warm front, or perhaps modify the
environment through an outflow boundary. There may still be some
shear and instability present early Saturday morning which could
allow for a a few organized updrafts. Would imagine most of it would
be elevated, thus only presenting a hail threat if anything at all.
For the rest of Saturday, the 594dam H5 high over the Gulf Coast
attempts to amplify which results in H5 height rises across the
area, and should help to clear conditions out. The surface low over
Texas though remains in place, and keeps weak WAA into the regime.
With clear skies, expect temperatures Saturday into the lower 90s
for southern reaches of the forecast area, with upper 80s toward the
Iowa border.
Sunday and Beyond:
The PV anomaly will send a strong trough and vort max southward late
Saturday and into Sunday toward the region. With a higher theta-e
airmass in place, on top of higher shear associated with the
vorticity max, another round of strong to severe storms is forecast
on Sunday. Probabilities for SBCAPE of at least 1000 J/kg or greater
is over 70 percent for much of the area. The SWODY3 has most of the
CWA in a slight risk. There is still discrepancy amongst solutions
about how the H5 low becomes closed off, as well as the amplifying
ridge to the west. Ultimately, the track may change if the vorticity
wraps around the low, or if the surface high pressure west of the
region is not nearly as strong. This could have the potential to re-
focus the forcing elsewhere. GEFS probabilities for at least 0.50
inches of rain is around 40 percent for most the area, indicating
that even if stronger thunderstorm forcing misses the area, there
should still be enough for some accumulating precipitation. Beyond
on Sunday, there appears to an amplifying ridge over the southwest
CONUS, with a deep trough over the the eastern third of the CONUS,
this will leave our region in a predominantly northwest flow regime
at least of the mid-levels. This should provide some relief from the
hot and humid conditions for a few days, before the ridge axis
slides further east and returns a WAA regime through the middle and
end of next week.
&&
.Aviation...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 700 PM CDT FRI AUG 11 2023
Chances for showers and thunderstorms continue tonight around the
KC and STJ terminals. Storms may form over the next couple of
hours then move off towards the east fairly quickly. Temperatures
cool toward the dew point which may lead to some FG/BR towards
sunrise. Additional storms are possible towards daybreak. These
storms are also expected to move off to the east fairly quickly;
however, confidence is fairly low in morning rain at this time.
Otherwise, VFR conditions are anticipated through the day
tomorrow.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory until 8 PM CDT this evening for KSZ057-060-103>105.
MO...Heat Advisory until 8 PM CDT this evening for MOZ037-043>045-053-
054.
&&
$$
Discussion...Krull
Aviation...Pesel
Area Forecast Discussion
National Weather Service Peachtree City GA
750 PM EDT Fri Aug 11 2023
...New 00Z Aviation Discussion...
.UPDATE...
Issued at 738 PM EDT Fri Aug 11 2023
Severe Thunderstorm Watch was trimmed out of north and central
Georgia earlier this evening as robust activity in the southern
zones moved south and out of the area. A few lingering strong
storms have persisted over north Georgia in the last couple hours,
but latest radar images are showing a steady downward trend in
intensity.
Have made a few minor updates to PoPs and temps this evening, but
otherwise, no significant changes. Overnight radiational fog will
be a concern, but at this time, widespread dense fog is not
expected.
31
&&
.SHORT TERM...
(This afternoon through Saturday)
MCV that came through with an MCS this morning has moved east of the
CWA this afternoon. 500mb analysis shows another little shortwave
moving in from east central AL. This feature will continue to help
fire showers and thunderstorms across central and south central
portions of the CWA through this evening. Strong storms are likely,
with a few severe storms possible, mainly across SW portions of the
CWA. The primary severe weather hazard would be damaging wind gusts.
Localized flooding is also possible...especially across west central
GA which has received 1"- 2" of rainfall already today.
The shortwave moving in from east central AL is interacting with a
weak frontal boundary situated just south of the Interstate 20
corridor. This boundary, and the NW flow aloft, are progged to go
anywhere through the short term period of the forecast. The hi- res
models continue to struggle with the anomalous NW flow aloft and
will base the pops this afternoon on current radar trends.
The forecast is a little bit more nebulous for tomorrow. Some of the
hi-res models are picking up on a wave/MCS moving in from the north
tomorrow afternoon. Since all models have trouble resolving these
MCS systems, have kept the pops limited to chance. However, the HRRR
did pretty good with the timing of this mornings MCS/MCV at this
time yesterday. It did struggle a bit with coverage though.
Temps are expected to be slightly above normal for Sunday with
continued high dewpoints. Have gone ahead and issued a Heat Advisory
for portions of the CWA. Some areas around Macon will have to be
watched for an Excessive Heat Warning if dewpoints are higher than
currently forecast.
NListemaa
&&
.LONG TERM...
(Sunday morning through next Thursday)
Main Forecast Points:
-Afternoon showers and storms expected through much of the extended
forecast with coverage and location tied to any remnant boundaries
and timing of weak mid-level disturbances.
-Heat returns this weekend and will stick around through early next
week. Forecast heat indices may warrant heat headlines particularly
for areas along and south of I-2O at the start of the long term.
Have issued an Excessive Heat Watch for portions of central and
south GA for Monday afternoon.
By Sunday, much of the southern U.S. will largely remain situated
beneath a flattened 500mb ridge with high pressure across the
southeast at the surface. As for what this means for us in
Georgia...heat and lower coverage of storms at least for the first
half of the long term. Warm temperatures and high dewpoints (mid to
upper 70s) will result in heat indices likely approaching excessive
heat warning criteria across much of south-central GA both Sunday
and Monday. Please make sure you`re taking care of yourself and
loved ones if you are partaking in any outdoor activities.
Any weak disturbances that make it through the mid-level flow may
aid in higher coverage of storms though largely expecting diurnal
storms (more typical of this time of year) through a good portion of
the period. Guidance remains consistent in depicting a more notable
trough that will translate across the Great Lakes Regions during the
Monday/Tuesday timeframe. Presently, the highest coverage of showers
and storms during the long term looks to be associated with this
system. The frontal boundary associated with this feature may
provide us with some much needed relief in the way of drier air
(lower PWs and dewpoints) slated to move in after the system moves
through. Similarly, this will push higher rain chances further south
and east.
07
&&
.AVIATION...
(00Z TAFS)
Issued at 738 PM EDT Fri Aug 11 2023
Expect precip activity to diminish in the coming hours. While VFR
conditions are generally expected, patchy SCT IFR ceilings and
MVFR visibilities will develop after 08-10Z and improve after
12-14Z. West winds will be light and variable overnight before
increasing to 5-8kt after 13Z. Additional storms are possible
again after generally 20Z, and have included in a PROB30 at this
time.
//ATL Confidence...00Z Update...
High confidence on winds.
Medium confidence on all other elements.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 71 92 73 95 / 30 30 30 20
Atlanta 73 92 74 96 / 30 30 30 20
Blairsville 65 86 68 88 / 10 30 20 40
Cartersville 71 91 71 94 / 20 30 30 20
Columbus 74 95 76 99 / 20 30 30 20
Gainesville 70 90 73 94 / 20 30 20 30
Macon 73 95 75 98 / 20 20 30 20
Rome 72 91 73 95 / 10 30 30 30
Peachtree City 71 93 72 97 / 20 30 30 20
Vidalia 73 95 76 97 / 20 20 30 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 10 AM to 8 PM EDT Saturday for GAZ039-049>051-
058>062-069>076-078>086-089>098-102>113.
Excessive Heat Watch from Sunday morning through Sunday evening
for GAZ039-049>051-058>062-069>076-078>086-089>098-102>113.
&&
$$
SHORT TERM...31
LONG TERM....07
AVIATION...31
AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1022 PM CDT Fri Aug 11 2023
.SHORT TERM...(This Evening through Saturday)
Issued at 229 PM CDT Fri Aug 11 2023
1. Isolated thunderstorms risks persist through Friday afternoon
and evening. A strong storm or two may be possible.
2. A split weekend is likely, with warm but dry conditions on
Saturday, but stormy weather potential on Sunday.
3. Quiet conditions arrive for next week, with what looks to be a
continued stretch of near normal temperatures.
-----------------------------------------------------------------
THIS AFTERNOON/EVENING: ACCAS field continues to move southeast
this afternoon indicative of sharpening mid-lvl lapse rates brought
on by slight cold air advection at 850 mb. A surface cold front
stretches from Gregory county northeast towards Marshall this
afternoon. Moisture ahead of the boundary remains limited, with
upper 50s and lower 60 dew points in most areas. We`ll continue to
watch a couple focal points for convection to deepen, best area of
mid-lvl lift is focused through the Minnesota river valley where the
strongest dPVA is located. More isolated activity would be possible
further southwest along the front as it reaches NW Iowa, but this
activity may only be pushed by weaker surface convergence. Within
the pre-frontal area, feel the RAP may be a bit more
representative of the overall instability profile than the HRRR,
which would indicate upwards of 1500 J/KG. Shear over the boundary
would be favorable for some rotating storms, suggesting the
potential for golf ball hail and isolated 60 mph wind gusts. Again
though, the development may be quite sparse.
TONIGHT: The passage of the surface front and arrival of high
pressure should clear out skies and bring light winds to the area.
Can`t rule out some valley fog as temperatures cool, but
probabilities are too low to include ATTM.
SATURDAY: Another fairly warm and dry day is expected Saturday as
mid-lvl heights rise slightly. Temperatures rise into the upper 80s
to lower 90s in most locations, but humidity levels stay quite low.
.LONG TERM...(Saturday Night through Friday)
Issued at 229 PM CDT Fri Aug 11 2023
SATURDAY NIGHT: A deeper upper trough drops southward across the
Northern Rockies late Saturday night into Sunday. In response, lee
side troughing increases and broad warm advection lifts northward
into the Dakotas. With the influx of moisture in the evening, we may
see elevated convection form across the Missouri River valley late
in the evening. A mixed mode of elevated supercells and multi-cell
convection could produce a risk for hail into Sunday morning.
SUNDAY: The trough quickly pivots southeast into central South
Dakota by mid-day, with persistent ongoing convection on the warm
advection wing of the storm lingering into the morning. The
latest guidance suggests that a surface cold front will begin
surging southeast by mid-day, eventually reaching the warm sector
across eastern Nebraska and northern Iowa early in the afternoon.
There remains some uncertainty on just how contaminated the warm
sector will be Sunday morning, but if the timing works out just
right, we could see early afternoon strong storms moving into
portions of far southeast South Dakota into Iowa/Nebraska. The
greatest rainfall amounts will be focused wherever the early
morning warm advection convection develops, where totals of 1" or
more could be possible. Broad QPF amounts of a quarter to half
inch may be possible through.
SUNDAY NIGHT: Winds will be quite gusty Sunday night into Monday as
the surface low moves east and the upper low swings through southern
Minnesota. While the NBM winds may be a little strong, there is
some potential for 30 mph gusts at times into Monday morning.
MONDAY-THURSDAY: We remain in this quasi-zonal to northwest
progressive upper flow pattern for much of the upcoming week. Mid-
lvl ridging in place through mid-week will keep dry conditions in
the area, with temperatures warming above normal by Wednesday. A
deeper trough looks to move through southern Canada by Wednesday,
though timing between the EC and GFS remain nearly 24 hours
apart. Much like we`ve seen the past week, capping ahead of this
wave looks to be fairly substancial, with limited moisture
advection ahead of the front. Therefore, will keep PoPs low at
this time.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1020 PM CDT Fri Aug 11 2023
VFR through the period. Showers and isolated thunderstorms will be
possible near and west of the James River from 0-6z Sunday, at the
tail end of the forecast period.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...Dux
LONG TERM...Dux
AVIATION...08
Area Forecast Discussion
National Weather Service Goodland KS
938 PM MDT Fri Aug 11 2023
.UPDATE...
Issued at 931 PM MDT Fri Aug 11 2023
Confidence has increased in fog developing along and north of a
Yuma to Hoxie line. Winds in response to a surface high in the
northern plains as winds look to remain from the ESE. Multiple
runs of the HRRR and now recently the GLAMP has been consistently
picking up on this area of fog developing, so opted to introduce
into the forecast. Localized dense fog is possible as moisture
advection increases from the east.
UPDATE Issued at 650 PM MDT Fri Aug 11 2023
Monitoring a shortwave moving into southern Colorado currently as
this will be the forcing for showers and storms Saturday. Cloud
cover will increase throughout the night which should help keep
temperatures a bit warmer in the mid to upper 60s across the area.
HRRR has been hinting at some fog development in along and north
of Highway 36 in Yuma, Dundy and Cheyenne counties with an arc of
moisture advection working into the area. I`m a little skeptical
of this as winds should remain from the WSW which is typically
unfavorable for fog formation so will leave that out but will need
to watched overnight.
Saturday morning, isentropic lift increases around sunrise along
and west of Highway 27 as PWATS increase to around 1.3 inches.
This should be enough for some showers and storms to develop.
Shortwave as mentioned above moves into the area late morning to
early afternoon as this will increase coverage of storms. RAP has
PWATS jumping up to 1.6 inches mainly along and south of Greeley
to Gove line. Effective shear increases 40-45 knots to support
supercell structure. There is some concern of a wet microburst
occurring if a mature supercell can develop mainly due to
precipitation loading. Will also need to monitor for torrential
rainfall with PWATS so high. I did trend high temperatures for
Saturday down some as there is concern of clouds and rain showers
limiting diurnal heating, however if sunshine can be more
plentiful then currently anticipated, then perhaps more of severe
threat can materialize.
Other change to the forecast I made was to increase winds along
and behind the cold frontal passage as the GFS20 is indicating a
3-4 mb pressure rise which would be supportive of sustained winds
of 25-35 mph and gusts up to 50 mph.
&&
.SHORT TERM...(This evening through Monday)
Issued at 125 PM MDT Fri Aug 11 2023
Cold front has settled along southern portions of the area this
afternoon where cannot completely rule out an isolated
thunderstorm developing in the late afternoon and evening hours.
Mesoscale analysis shows that area is very unstable with effective
shear of around 35 kts. So, if something should develop it could
potentially be severe with large hail and damaging winds.
Confidence, however, is very low with almost no model support.
Otherwise, expecting increasing clouds tonight from the southwest
with low temperatures in the 60s.
For Saturday, models a little more bullish with precipitation
chances associated with a shortwave trough rotating in from the
southwest around the upper ridge. HREF shows light showers
developing early Saturday morning along and south of the Palmer
Divide then spreading eastward Saturday afternoon and finally
exiting Saturday night. Given the early start and cloud cover,
CIN will be a concern. However, MUCAPE and shear will be
plentiful and should surface based storms develop they would
likely become severe. There does appear that there will be a more
robust line of storms Saturday evening moving out of southeast
Colorado and into southwest Kansas, possibly clipping southern or
eastern counties with a damaging wind and hail threat. Confidence
is on the low side for severe threat on Saturday, but SPC has
basically areas south of Interstate 70 in a Marginal Risk and a
Slight Risk just to the south. Cooled temperatures just a bit into
the 80s for highs due to expected cloud cover, with lows Saturday
night in the 60s.
For Sunday, another cold front moves through early in the day
associated with northern stream shortwave trough. A few hours of
gusty northwest winds up to 40 mph will accompany the front. More
models showing a faster frontal passage which would translate to
lower precipitation chances and cooler temperatures. Might see
some showers or isolated storms mainly in eastern areas with the
front around 18z, but risk of severe storms should stay south and
east with the front later in the afternoon. High temperatures will
range from the upper 70s in northeast Colorado with early fropa
to the upper 80s in north central Kansas with the later fropa. Low
confidence in the chance for precipitation chances Sunday night
with the front far south. Low temperatures Sunday night will
generally be in the 50s, but if skies can clear would not be
surprised to see a few locations in the upper 40s with the lower
dew points and radiational cooling.
Monday will see cooler temperatures and stable conditions as an
upper ridge builds in from the west. High temperatures will be in
the upper 70s to lower 80s with sunny skies and light northwest
winds. Lows Monday night will be in the 50s.
.LONG TERM...(Tuesday through Friday)
Issued at 1253 PM MDT Fri Aug 11 2023
Precipitation potential continues to lower for next week; dry
conditions likely.
Midweek a strong short wave trough moves through, pushing the ridge
south. However, the ridge looks to build back fast enough behind the
incoming trough that the rainfall potential is shunted east of the
forecast area. Behind the trough there will be a bit of a cool down,
but dry weather is still expected. Interesting to note that the
latest run of model data has deepened the trough mid week. The
deeper the trough becomes the slower to the southeast it should
move. This could help with rainfall chances. However confidence
remains low that there will be any precipitation with the front. If
the front moves through during the day there could be gusty winds
with it due to the temperature gradient along it. Am not too
concerned about blowing dust potential yet. However am not sure how
reliable the model data can be at this time range given the
variability that is shown with the frontal timing. Blowing dust
will be more likely if the front moves through during the afternoon
with a drastic drop in temperature behind it.
The upper level ridge will build back over the Plains behind the
cold front. ECMWF and GEFS data show the ridge centered over the
Central Plains. This will result in temperatures gradually warming
through the week.
The warmest day of the week will be ahead of the incoming short wave
trough and associated cold front. That could be Wednesday or
Thursday, depending on when the trough will move through.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 438 PM MDT Fri Aug 11 2023
VFR conditions are currently forecast for this TAF period. Clouds
will be on the increase through the night becoming OVC at KGLD by
sunrise as a shortwave trough moves towards the area. Along with
this trough brings chances for showers and eventually storms for
KGLD; opted to go with VCTS as there is some uncertainty with
how widespread the precipitation chances will be. Chances for
precip currently don`t look as favorable for KMCK so will leave
out for now.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...Trigg
SHORT TERM...024
LONG TERM...JTL
AVIATION...Trigg
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
1030 PM EDT Fri Aug 11 2023
.SYNOPSIS...
A disturbance moves through the region Saturday bringing
rounds of showers and thunderstorms throughout much of the day. The
area briefly dries out on Sunday before another low pressure system
moves into the area Sunday evening, bringing renewed chances for
storms into the start of the work week. Drier and slightly
cooler conditions for Tuesday and beyond.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Forecast appears to capture the progression of the shortwave
across the Great Lakes this evening, so no major updates needed
at this time.
Main concern for the overnight is timing a potential MCS
developing across northern Missouri just after midnight and
progressing toward the southeast through the early morning.
Latest CAM guidance indicates most of the system moves to our
southwest toward the highest instability. However, there
remains a chance of some weakening convection on the north end
of the MCS that may produce showers and thunderstorms, mainly
across the Tri-state perhaps as far north as the Miami Valley.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Any ongoing AM convection should be moving through the area
Saturday morning. Additionally, any AM storms will likely
overturn the environment into the early afternoon hours,
potentially inhibiting afternoon thunderstorm development.
As the parent system continues to work its way east, it will
drag a cold frontal boundary along with it Saturday afternoon.
Current thinking is that this boundary will be the focus/ help
force some afternoon storm redevelopment, particularly in our
north and east. Primary threat would be strong/damaging winds;
small hail and localized rainfall is also possible.
As the front slowly pushes southeast through the region, storm
coverages decreases into the evening hours. Overnight lows drop
to the low 60s in the north (where clouds clear out faster) and
low 70s in the south.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
H5 level generally exhibits zonal flow over the Ohio Valley on
Sunday. As we progress through the day, models show several
shortwave ripples of energy that traverse through this upper flow
pattern. Given the relatively moist and unstable air mass, this
ripple of energy will be enough forcing to increase precip coverage
across the CWA by the afternoon/evening hours. Based on latest
guidance, there will be a relative minimum in pcpn coverage during
the early part of the night. Closer to 09z, there will be a
noticeable increase in LLJ flow into the Tristate region, with 850mb
winds approaching 50 kts. This LLJ surge will increase heavy rain
potential through early Monday morning. There will be convective
elements in these showers, and with some ensemble members showing
PWATs near 2.0" early Monday, there will certainly be some efficient
rainfall. Will have to monitor antecedent rainfall Sunday as wet
soils may increase potential for flooding/flash flooding through
early Monday.
Monday will be extremely muggy as models are suggesting dewpoints
over 70 degrees for most, with some locations near/south of the OH
River even approaching the mid-70s. Given the large complex of
showers/storms that are expected to move through Monday morning,
there is some uncertainty if there will be the potential for any
strong to severe storms developing again later in the afternoon
Monday. The main slug of pcpn ejects eastward by Monday evening. A
very robust H5 trough begins to swing through our CWA Monday night,
which would lead to additional rounds of light showers through
Tuesday. Seasonably cool temperatures will be in place Tuesday as
the mean trough scoots across the Ohio Valley. However, dewpoints do
not take a steep dive as models continue to hang onto dewpoint
values around 60.
Wednesday and Thursday trend dry as weak H5 ridging briefly builds
back in. Global models do show another robust trough swinging
through the Midwest region late Thursday into Friday, which will
bring our next round of pcpn.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Quiet night is likely in store for the TAF sites. Latest HRRR
guidance has trended further south and west for a convective
system developing over northern Missouri. It now appears this
organized thunderstorm complex may dive southeast, leaving just
a chance of thunderstorms for the Cincinnati TAF sites in the
post-dawn hours.
For Saturday, a cold front will drop south out of the Great
Lakes, bringing enhanced chances for convection from late
afternoon into the evening. Best chance of impacts from the cold
front will be at the Columbus terminals. Have stuck with showers
at this time until we can have higher confidence on the timing
of the frontal passage.
Winds will begin to shift from the southwest to the northwest
near the end of the TAF period behind the cold front.
OUTLOOK...Thunderstorms possible Sunday night through Monday
evening.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...CA
NEAR TERM...
SHORT TERM...CA
LONG TERM...Clark
AVIATION...
Area Forecast Discussion
National Weather Service Indianapolis IN
1000 PM EDT Fri Aug 11 2023
.Forecast Update...
Issued at 1000 PM EDT Fri Aug 11 2023
Impulse in NW upper flow and modest 25 knot 850 jetlet in
combination with the Moderate W-E CAPE axis, over northern parts of
Illinois and Indiana resulted in strong convection over northeastern
Indiana this evening. However, that convection is moving into Ohio
with the wave. So, this should not be an issue the remainder of the
night for our far northeastern counties. Otherwise, IR satellite was
showing mostly clear skies over central Indiana this evening, and
this should be the case heading into the overnight.
However, HIRES models are keying in on modest nocturnal jet
interacting with extreme instability and intersecting a boundary
over northern Missouri as an anomalously strong 100 knot upper jet
dives southeast across the western Great Lakes, around the base of
an upper trough, in the fast northwest flow. CAMS have convection
blowing up late this evening and early overnight over northern
Missouri and then diving southeast across central or southern
Illinois overnight. Confidence is not overwhelming whether or not
this convection will clip any of our lower Wabash Valley counties or
not toward daybreak, especially since the convection upstream has
yet to develop. That said, there is enough of a chance that this
complex will plow through some of our SW counties that a Day1 Slight
Risk of severe weather looks reasonable. There is even a lower
confidence convection will make it as far east as I-65, where a
marginal risk extends.
Regarding timing, CAMS tend to be on the slow side when significant
cold pools develop, so would not be shocked if convection is nearby
a few hours prior to daybreak. Still, confidence is low how far into
central Indiana any convection will get or as previously discussed
if southwest sections only get clipped or missed in NW-SE storm
movement.
Heavy rain will be of some concern if the convection does in fact
reach SW sections. However, big progressive nature of the convection
suggests widespread flood chances are low. Will keep PoPs on the
chance side. With convective mixing and or debris, fog is not a huge
concern, although would not rule out brief deterioration similar to
last night in low lying areas or near water sources.
Dew points in the upper 60s and lower 70s and southwest winds
suggest temperatures will fall no lower than that.
&&
.Short Term...(This evening through Saturday)
Issued at 300 PM EDT Fri Aug 11 2023
This afternoon...
A dying MCS is covering the CWA with cloud debris, limiting the
available instability for afternoon convection and causing gusty
winds. Any convection that forms will likely be short-lived and
isolated. High temperatures should hover around the mid-80s due to
residual cloud cover during peak heating hours.
Tonight and tomorrow...
A 500mb ridge starts to build back into the Indiana area, once again
resuming the upper-level northwesterly flow and weak surface wind. A
southwesterly 850mb jet ramps up overnight, advecting warm, moist
air into Central Indiana. This warm, moist air could fuel early
morning convection as a shortwave feature moves through the Great
Lakes. Models are in a lot of disagreement on whether this
convection will form, and if it does, what time it would form. It is
unknown whether the convection would be in the form of an MCS or
organized cells. Unlike Friday, conditions are expected to be much
more suitable to support convection. Models show a 40-50kt 500mb jet
dipping into our CWA, potentially allowing for cellular convection
to become organized and sustained. Again, it is unclear if and when
the upper-level perturbation will initiate convection in our CWA.
In the early morning hours, the GFS LAMP and HRRR are showing light
surface winds, clear skies, subsidence, and residual moisture -- a
favorable environment for fog formation. Open areas, agricultural
fields, and areas near rivers have the best chance for fog formation
in the early morning Saturday. If convection were to occur around
sunrise, confidence in fog formation significantly decreases
as air becomes more mixed.
&&
.Long Term...(Saturday night through Friday)
Issued at 300 PM EDT Fri Aug 11 2023
* Active weather early in the week.
* Quieter and mild much of the week.
Northwest flow aloft very early in the period will quickly become
more amplified this week, as the upper level ridge restrengthens
over the southwestern CONUS, with at least a couple of fairly potent
upper level lows, particularly for the time of year, sliding through
the region.
Appears that whatever late day convection forms on Saturday will be
gradually diminishing/exiting the area Saturday evening, with the
focus for additional development to our southwest late Saturday
night into early Sunday along a low level baroclinic zone and
accompanying a subtle upper level wave moving out of the southern
High Plains. This activity may make it into the area in some form
Sunday afternoon into Sunday night, with some intensification
possible if the timing does end up being diurnally favorable.
Presence of a strengthening low level jet late Sunday night may help
compensate for nocturnal stabilization, particularly if convection
upstream already features a well-developed cold pool. Convective
evolution late in the weekend will depend heavily upon prior
convection, and thus remains highly uncertain, but day 3 marginal
risk is reasonable based on current guidance.
Stronger synoptic low will move through the Great Lakes Monday into
Monday night, with additional showers and thunderstorms expected,
before broad high pressure builds into the area, moderating already
seasonable temperatures, and bringing dry conditions for mid week.
Another upper level wave and cold front late in the week may bring
some showers to the area Thursday afternoon and evening.
Temperatures through the period will be near to below normal,
perhaps much below normal at times, with highs only in the 70s.
Blend numbers required some minor adjustment but generally appeared
to be in the ballpark.
&&
.Aviation...(00Z TAF Issuance)
Issued at 638 PM EDT Fri Aug 11 2023
Impacts:
- Brief MVFR and worse flying conditions in fog possible 09z-12z at
smaller airports
- Brief MVFR and worse flying conditions possible in thunderstorms
possible after 06z Saturday with better chances after 12z
Discussion:
Combination of convectively induced of enhanced waves in the fast
upper northwest flow aloft, an approaching cold front and warm,
moist and unstable atmosphere will bring the potential for
thunderstorms overnight tonight and Saturday with the highest risk
any one terminal will see an impact after 12z. If overnight
convection doesn`t develop or upstream convective debris does not
keep areas from radiating enough, could once again see some brief
MVFR and worse fog at the smaller airports toward and just after
daybreak.
Winds will be southwest less than 10 knots tonight and 10 knots or
more with gusts possible Saturday afternoon. Gusts may also briefly
be higher in thunderstorms. Winds will shift to the west and
northwest late over terminals that the cold front clears.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...MK
Short Term...BRB/Monaghan
Long Term...Nield
Aviation...MK
Area Forecast Discussion
National Weather Service Northern Indiana
909 PM EDT Fri Aug 11 2023
.SYNOPSIS...
Issued at 215 PM EDT Fri Aug 11 2023
Isolated showers and thunderstorms are expected late this
afternoon into early evening north of route 30 and again Saturday
afternoon south of route 30. Otherwise seasonably warm this
weekend with highs in the mid to upper 80s.
&&
.UPDATE...
Issued at 900 PM EDT Fri Aug 11 2023
A few clusters of showers and storms were persisting mainly east
of I-69 across portions of eastern IN into NW Ohio. A few storms
attempted to gain some intensity, but failed to maintain it. HRRR
still handling evolution fairly well with slow decrease in
convection expected over the next couple hours with loss of
daytime heating and departure of the wave helping with
development. Pops were cleaned up a bit ago to reflect current
trends through 6Z.
Focus then shifts NW with broken line of strong to severe storms
from central WI to northcentral IA. The overall area has
accelerated somewhat in its SE propagation, but challenges still
exist as to how far SE it will make it with most CAMs still
showing a weakening trend before arriving in the 6-9Z time frame.
Did increase pops slightly in NW areas (limited to slgt chc to
chc) for the time being and continue to watch trends. SPC
maintained the marginal risk in NW parts of the area for a wind
threat.
&&
.SHORT TERM...(This afternoon through Saturday)
Issued at 215 PM EDT Fri Aug 11 2023
Earlier MCS that moved out of IL continues to decays overhead as it
moved out of better upstream instability plume. Some penchant exists
far east for an isolated storm yet through mid aftn ahead of shallow
leading vort max. More favorable uptick in low level flow expected
thereafter this evening ahead of more vigorous disturbance tracking
ewd out of WI into MI overnight. Broad mass flux within building H85
theta-e ridging should yield iso storms aft 21Z and persisting
perhaps into mid evening far east although generally capped by
limited sfc based instability.
Otherwise cold frontal zone lags Sat with secondary, more vigorous
theta-e ridging developing by aftn w/iso-sct mainly aftn storms
generally US30 south.
&&
.LONG TERM...(Saturday Night through Thursday)
Issued at 215 PM EDT Fri Aug 11 2023
Brief post frontal drying follows into Sun ahead of robust sys
digging sharply sewd out of the nrn plains and across the lakes Mon.
Better forcing expected well north in MI as poor frontal based
timing here precludes much more than showers.
Thereafter quiet and seasonably cool as Canadian high pressure
builds in through Wed before dislodging ahead of another vigorous nrn
stream disturbance digging into the nrn lakes late week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 533 PM EDT Fri Aug 11 2023
Threat for convection will likely remain just NE of both TAF sites
prior to 00Z (but will leave VCTS for now in existing 18Z TAFs).
Monitoring upstream storms developing across NE WI into S MN that
will dive SE and may survive to some extent late tonight into
KSBN. Models struggling on handling of this resulting in continued
omission of any mention in overnight period of 00Z TAFs. Frontal
boundary will drop south through the day Sat with a switch the NW
on winds.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...Fisher
SYNOPSIS...T
SHORT TERM...T
LONG TERM...T
AVIATION...Fisher
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Area Forecast Discussion
National Weather Service Louisville KY
947 PM EDT Fri Aug 11 2023
.Forecast Update...
Issued at 945 PM EDT Fri Aug 11 2023
After a day with temps reaching the upper 80s, sfc temps across most
of the region are already in the mid to upper 70s. We`ll see temps
bottom out overnight in the upper 60s and low 70s. Evening update
does not feature much change, and the going forecast is in overall
good shape. However, low confidence remains for tomorrow morning in
regards to a possible decaying MCS. With the 00z HRRR coming in now,
general initialization is decent, with the guidance further decaying
the current showers over northern Missouri in the next few hours,
though it is not initializing well with the severe cluster of
convection over northeastern Oklahoma. Additionally, the possible
arrival of storms during the diurnal min time frame also adds to the
low confidence forecast. What is interesting to see is that the
incoming 00z HRRR is fairly similar to the 18z NAM Nest in regards
to storm coverage and timing for our area tomorrow morning.
CAMs continue to suggest MCS initialization over the Iowa/Missouri
border sometime around 04-05z tonight, and diving southeastward
through eastern Missouri and central Illinois, possibly arriving in
our northwest CWA by 12z tomorrow. Forecast soundings from the 00z
HRRR suggest the nocturnal inversion to be eroding by the time the
cluster will be approaching, potentially resulting in better sfc
based instability than previously thought. If this MCS does develop
as some of the CAMs suggest, and if it does make it to our area
tomorrow morning, primary threat would be damaging wind gusts given
the healthy amount of DCAPE in soundings.
&&
.Short Term...(This evening through Saturday)
Issued at 253 PM EDT Fri Aug 11 2023
Low-confidence forecast, especially for the short-term as neither
CAMs nor synoptic models have a great handle on the ongoing
convective setup. Main area of convective initiation thus far has
been roughly between Kansas City and Omaha, and not really showing
in any of the models. This activity is likely to dive SE into
western Kentucky before daybreak. At this point, later evening
initiation along the Iowa/Missouri border would have a chance to
push a MCS across southwest Indiana into the Pennyrile by daybreak
Sat, maybe decaying as it continues into mainly south-central
Kentucky. With most of our CAPE elevated by that time, a morning SVR
threat would be minimal, but localized near-severe gusts couldn`t be
ruled out.
Our better chance at severe convection would depend on the
atmosphere being able to reload, which is not a given as we could
have extensive debris cloudiness from a morning MCS. If we do
somehow destabilize, 30-40 kt mid-level winds could support a
damaging wind threat especially if low-level lapse rates steepen,
with even better dynamics to our north along the cold front draped
across central Indiana.
Not enough confidence in the severe weather setup to get very
specific with messaging, but strong to severe storms will be
possible at some point during the daytime hours on Saturday, with
damaging winds as the primary hazard. Overall chance of measurable
precip will push 60 percent across parts of southern Indiana during
the morning, but otherwise scattered coverage of thunderstorms may
be on the generous side.
.Long Term...(Saturday night through Friday)
Issued at 328 PM EDT Fri Aug 11 2023
Key Messages:
- Potential for strong to severe storms Sunday night and Monday.
- Localized flash flooding issues cannot be ruled out.
Synopsis...Complex weather scenario will unravel this weekend and
early next week for the lower Ohio Valley as several waves of
unsettled weather bring potential for severe weather to the region.
The mid-level synoptic pattern will tend to amplify this weekend as
tropical energy helps to spin an upper-level low over Baja
California and an amplifying ridge settles across the Pacific
Northwest, forming a Rex blocking pattern. Meanwhile, the downstream
portion of the CONUS will be characterized by a quasi-stationary
ridge over the Southeast and Gulf Coast with the active jet confined
to the northern Plains and the Great Planes. As a result, several
pronounce shortwave troughs, and associated cold fronts, are
forecast to track across the Great Lakes and Ohio Valley.
Model Evaluation/Confidence...Global deterministic and ensemble
guidance has come into better agreement regarding the timing of the
first strong shortwave trough (Monday), but the Cluster Phase Space
analysis still indicates that CMC and ECMWF are better phased
compared to the slightly faster and stronger GFS solution. Moreover,
there is somewhat fair consensus on the QPF placement for Sunday
night into Monday morning as most the 10/11Z guidance consulted show
a broken swath of 1-3 inches of rain zonally oriented across the
lower Missouri Valley into northern KY/southern IN. As for the
mesoscale environment, there is sufficient uncertainty in the hi-res
models to only indicate a conditional risk of severe weather
Saturday evening, while severe chances look a tad more impressive
for Monday given the synoptic factors at play and the idea of a fast
mesoscale recovery.
Saturday Night - Sunday...As stated above, there is a conditional
risk of severe weather Saturday evening as expectations are for
cellular convection to form ahead of southward-sagging cold front.
There has is great variability in the location, coverage, and even
storm initiation during that time frame as only HRRR has maintained
storms with the 11/12Z run. One of the main factors playing a role
here is earlier MCS activity over the area which could negatively
impact the chances of destabilization and boundary-scale forcing.
Nonetheless, if storms do materialized close enough to the forecast
area, as shown by the HRRR and to a less extent RRFS, then a
conditional risk of damaging winds and hail will exist for southern
Indiana/northern KY for a small window given enough deep-layer shear
and moderate CAPE.
Sunday Night - Monday...There are arguments to support a bigger
threat of severe weather during this period as there seems to be two
independent episodes during this period. The first wave of concern
will be related to a MCS activity accompanying a vorticity maxima
ahead of the approaching shortwave trough Sunday night into Monday
morning. The MCS will be also be driven by a fairly strong (40-50
knot) nocturnal LLJ, deep-layer shear, and moderate elevated
instability, so a linear MCS with bowing segments is not out of
question. The QPF swaths indicate that such system might tracking
along northern KY/Southern IN, where forecast soundings depict
strengthening low-level inversion. Therefore, the main weather risks
for the aforementioned time is damaging winds (if DCAPE > DCIN),
lightning, and a flash flooding risk given efficient rainfall rates
and wet soil conditions in some areas.
The second wave of potentially strong to severe storms will be
associated to the cold front itself during the afternoon and evening
hours on Monday. There is still much uncertainty in the details that
involve the preconvective environment recovery (given morning MCS)
and frontal timing, so a broad area of severe risk has been drawn by
SPC along central and eastern Kentucky. That being said, models are
advertising storm initiation along and ahead the cold front Monday
afternoon which will overlap with maximum peak heating and strong
shortwave dynamics to mention all a risk of all severe weather
hazards (tornado, wind, and hail). Last but not least, the favored
convective mode would be, initially, supercellular as the deep-layer
shear vector will have an oblique orientation relative to the
frontal boundary.
Tuesday and beyond... A dry and cooler-than-normal spell will be
arriving to the lower Ohio Valley on Tuesday and probably last to
the end of the workweek. The pressure gradient force between the
departing front and incoming surface high pressure will account for
gusty winds on Tuesday, which at the same time will advect a more
stable airmass to the forecast area. A second shortwave trough and
attendant cold front will be swinging by Thursday or Friday, but any
chances of precipitation and/or storms will depend on the amount of
instability available.
&&
.Aviation...(00Z TAF Issuance)
Issued at 715 PM EDT Fri Aug 11 2023
Diurnal cu field has diminished as the sun begins to set. Should be
a fairly quiet night with VFR conditions and light winds from the
south. There continues to be low confidence as we head into tomorrow
morning with a storm cluster diving into our region from the
northwest. Will continue to carry PROB30 groups for shower mention,
though still could see a low-chance for TS/CB especially for SDF
and/or HNB tomorrow morning. Confidence is even lower for the
afternoon, which really is conditional on what the morning brings.
If a drier morning occurs, then we should have a better chance for
afternoon storm activity to impact the terminals. But if we do see
morning activity, that could limit the afternoon potential for
storms. Otherwise, expect diurnal cu field and SW winds picking up
to just over 10 kt around the end of the TAF period, with some gusts
just shy of 20 kt in the planning period at SDF.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...CJP
Short Term...RAS
Long Term...ALL
Aviation...CJP
Area Forecast Discussion
National Weather Service Morristown TN
1048 PM EDT Fri Aug 11 2023
...New UPDATE...
.UPDATE...
Issued at 1013 PM EDT Fri Aug 11 2023
Forecast is on track this evening, so no edits were made to the
near term forecast. Only edits were to adjust Sunday and Monday
dewpoints downwards. Satellite imagery shows some patchy low
level clouds along the Plateau and Virginian counties, expecting
patchy fog across the valley overnight given the clear skies and
light winds. Remainder of the night will remain dry.
&&
.SHORT TERM...
(This evening through Saturday)
Issued at 250 PM EDT Fri Aug 11 2023
Key Messages:
1. Showers or rumbles of thunder will diminish this evening with
patchy fog by the morning.
2. Confidence has increased in strong to severe storms on
Saturday with damaging winds as the main threat and some potential
for hail.
This Evening/Tonight
Currently this afternoon, the region is in a northwesterly flow
pattern aloft with a stationary frontal boundary to the south.
Diurnal heating and embedded shortwaves have allowed for
development of showers and isolated thunderstorms in the south,
where moisture and instability are higher. This activity will
continue to diminish this evening with the loss of heating. As
conditions clear and moisture lingers from any earlier showers,
fog development is likely in many places by the early morning
hours. Also during this time, the frontal boundary and low-level
moisture will be pulled northward through the night as low
pressure moves into the Great Lakes.
Saturday
During the day on Saturday, the region will remain in a
northwesterly flow pattern aloft and well within a broad area of
significant low-level moisture and heating. This heating in the
low-levels will make for impressive thermodynamics with most
high-res model sources suggesting MLCAPE to reach well above
2,000 J/kg by the afternoon hours. This is especially true in the
southern half of the area where the HRRR has values in excess of
3,000 J/kg. This will also be accompanied by DCAPE above 1,000
J/kg. The vertical wind profile shows some veering, but fairly
weak flow looks to limit deep-layer shear to 25 kts or less. With
all of these factors in mind, most model sources suggest
development and progression of an MCS or organized multicells into
our area by the mid-afternoon hours. The HREF highlights most of
the area with a strong signal for high winds and updraft tracks,
especially south of I-40. Given these indications, confidence has
increased in another potential damaging wind event with some
uncertainty remaining in exact timing and location. With the
impressive instability and updraft tracks, some hail will also be
possible but inhibited by melting. Messaging will definitely be
increased, given the likelihood of damaging winds in our area.
&&
.LONG TERM...
(Saturday night through next Friday)
Issued at 250 PM EDT Fri Aug 11 2023
Key Messages:
1. Multiple rounds of showers and storms are possible Sunday and
Monday alongside muggy conditions. Heat indices could approach 100
degrees for central and southern portions of the area at times, and
some storms may become strong to severe.
2. Cooler and drier temperatures are expected for the remainder of
the extended.
Discussion:
For Sunday, a weak disturbance will translate through mean flow
aloft. Associated lobes of vorticity will aid convective initiation
with isolated to scattered showers and storms possible at times.
Model derived soundings from the GFS suggest MLCAPE could approach
near 2000J/kg with DCAPE near 1000J/kg(primarily in the southern
valley - lower values northward) in the afternoon. NAM soundings
contain values slightly higher. Combined with modest lapse rates,
there remains opportunity for any storm to become stronger or
possibly severe, again, with a primary focus across southern
portions of the Tennessee Valley and Cumberland Plateau. Isolated
damaging wind and hail will be the main threat.
Increasing chances of showers and storms are anticipated mid Monday
as a warm front lifts northward in response to a more potent
shortwave swinging into the Ohio Valley, leaving the forecast area
within the warm sector. It currently looks like the better chances
for Monday afternoon activity will be in northeastern sections,
however, a cold front will approach the region Monday evening/Monday
night bringing increasing PoPs area wide. Timing will play an
important role regarding the extent of severe weather potential as a
slower passage may result in fading instability overnight.
Nonetheless, the above normal temperatures/moisture availability and
anomalous dynamics will result in additional chances for strong to
severe storms.
One additional point for the Sunday and Monday time frames will be
the muggy conditions. Portions of the southern and central valley
could see heat indices approaching 100 degrees in the afternoon.
Storm timing and coverage could impact this to some degree. Cooler
and drier conditions will return post-FROPA, with the exception
being some lingering light activity in association with wrap around
moisture Tuesday. Otherwise, slightly below to near normal
temperatures and mostly dry conditions return for the remainder of
the week.
&&
.AVIATION...
(00Z TAFS)
Issued at 729 PM EDT Fri Aug 11 2023
VFR conditions will deteriorate to MVFR VIS at CHA and TYS, IFR
VIS and CIGs at TRI by 9z tonight as fog develops in the valley.
A return to VFR for all sites by 13-14z as morning fog dissipates.
Introduced a PROB30 group for the possibility of an afternoon
thunderstorm complex, mainly between 19z to end of the period, with
lesser confidence at TRI. Outside of any thunderstorms, calm
overnight winds will increase to a gentle southwesterly wind
during the day.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 73 92 72 92 / 0 40 30 50
Knoxville McGhee Tyson Airport, TN 70 89 72 89 / 0 60 30 50
Oak Ridge, TN 70 87 70 88 / 0 50 40 60
Tri Cities Airport, TN 66 86 69 85 / 0 30 40 50
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...Wellington
LONG TERM....KRS
AVIATION...Wellington
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 245 PM CDT Fri Aug 11 2023
Key Messages:
- There is a Marginal to Enhanced Risk (Levels 1-3) for severe
weather in southeast Nebraska and southwest Iowa from 3 PM
until 10 PM.
- There is a Marginal Risk for severe weather tomorrow in
northeast Nebraska.
- There is a Slight Risk for severe weather Sunday ahead of a
strong cold front that is forecast to move through the area.
Today:
As of 2 PM, some very high based convection is ongoing across
southeast Nebraska and southwest Iowa. A few hail reports have
been submitted and they`ve ranged from pea sized to 2 inches. This
is the first of two expected rounds of severe weather today. The
2nd round is expected to develop in southeast Nebraska and
southwest Iowa. The 2nd round is expected between 3 PM and 10 PM.
A very unstable environment will develop with both the HRRR and
RAP showing MLCAPE reaching 3000-4000 J/kg. Straight line
hodographs indicate supercell development initially. Clusters and
splitting storms are expected after the initial development. Mid-
level lapse rates near 8 C/km support a very large (2+ inches)
hail threat. Damaging wind gusts are also a possibility with DCAPE
values near 1500 J/kg.
Saturday and Sunday:
A surface high will move from the Dakotas into Iowa on Saturday
which should lead to a mostly quiet weather day, at least
initially. Skies will be mostly clear, the winds light, and
temperatures will warm into the upper 80s and lower 90s. A weak
shortwave will pass over the area late Saturday afternoon which
could initiate late afternoon or evening storms. CAMs do show some
isolated, scattered storms developing. However, they may be under
doing it as forecast soundings across the area show dewpoint
temperatures at the surface in the 50s while the forecast is for
mid 60s. There could be more instability than the models currently
indicate. Outside of instability, shear, helicity, and lapse
rates are less favorable for widespread severe weather. That said,
warm air advection combined with limited instability could result
in at least pop-up rain showers across the area in the late
afternoon and evening.
There is a severe weather threat on Sunday ahead of a shortwave
trough that is expected to move from the Canadian Plains to the
Great Lakes region. This system will be dynamically and
kinematically strong but the severe weather threat is uncertain
due to the timing of the system and potential precipitation Sunday
morning. Strong warm air advection ahead of the low could lead to
early morning precipitation across the area. The cloud cover
could prevent adequate instability from building. The latest GFS/ECMWF
are in better agreement on timing and it looks like the front is
going to pass through area in the late afternoon. An afternoon
frontal passage may only allow for adequate instability to build
in the far southern areas of the forecast area as highlighted by
the SPC Slight Risk.
Monday through Thursday:
This period is expected to remain mostly dry and initially cooler.
Temperatures on Monday and Tuesday are forecasted to range from
the mid 70s to the mid 80s. Warmer temperatures return Wednesday
and precipitation chances return on Thursday as the end of the
weeks looks to be more active.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 545 PM CDT Fri Aug 11 2023
VFR conditions are expected to prevail at all TAF sites throughout
the forecast period. Current observations show surface dewpoints
across southeast NE/southwest IA are higher than current short
range model guidance. This coupled with clear skies and light
winds overnight suggest low fog potential south of the I-80
corridor. Any fog that develops should stay south and east of TAF
sites. Isolated showers and thunderstorms are also anticipated
across portions of northeast NE. The highest risk for
precipitaiton will be around KOFK, but potential is too low to
include in TAFs at this time.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...Fajman
AVIATION...Kern
Area Forecast Discussion
National Weather Service Nashville TN
759 PM CDT Fri Aug 11 2023
...New UPDATE...
.UPDATE...
Issued at 748 PM CDT Fri Aug 11 2023
Earlier cells that clipped the SW corner of the CWA have vanished
and there are currently no echoes anywhere in Middle Tennessee.
The 00Z sounding from OHX does show a highly unstable environment:
SBCAPE of 2,659 J/kg and LI of -7. However, there is also an
elevated inversion centered around 850 mb that is having a
negative impact on mid-level lapse rates. Also, the PWAT is a
little dry at 1.40". The synoptic pattern is rather broad and
diffuse, as one might expect this time of year. Weak high pressure
at the surface has spread across much of the southeast U.S., but
this is balanced by frontal boundary over the upper midwest and
Great Plains. This boundary is going to sag southeastward
overnight, and the HRRR has persistently show an MCS dropping into
Middle Tennessee from the north late Saturday morning. At this
time, Middle Tennessee remains under a marginal risk of severe
storms tomorrow as a result of the expect convective complex.
Otherwise, expect a night of quiet weather across the mid state.
&&
.SHORT TERM...
(This afternoon through Saturday Night)
Issued at 229 PM CDT Fri Aug 11 2023
The rest of today is expected to be mostly clear with temperatures
near 90 degrees. We are currently situated in an upper northwesterly
flow with some deep short waves developing in the southwest.
Models are showing this upper level disturbance moving into our
region in the early part of Saturday. This will be the main
lifting source for the development of an MCS Saturday morning.
Short-term models indicate the MCS will move into middle Tennessee
from the northwest around 10 am and is expected to move into the
Cumberland Plateau into the early afternoon hours. A few stray
showers may linger after the main line of storms, but the rain
should clear up for the evening. Overnight Saturday into Sunday
morning will bring us additional rain chances as well with the
possible development of a second MCS. This second MCS appears to
have a less developed structure in most of the CAMS. Earlier
storms from the first MCS Saturday morning could limit the
severity and development of storms overnight by stabilizing the
airmass overhead. As such, models are in disagreement with timing
with some like the HRRR not even showing precipitation.
&&
.LONG TERM...
(Sunday through next Friday)
Issued at 229 PM CDT Fri Aug 11 2023
Sunday we start to see our upper-level flow becoming more zonal
with another short-wave trough moving over the TN valley Sunday
morning. This will bring PVA and precip chances for Sunday
morning. The GFS shows a cold front moving into TN Monday
afternoon. This will bring in another chance of storms, with some
possibly strong to severe. Afterwards, slightly cooler and drier
conditions will prevail with max temperatures being in the low
80s. Upper level ridging will maintain these conditions. By
Wednesday, our 500mb heights will be broadly spread out leading to
low upper level winds. From Wednesday into Friday we see that the
upper high over Texas and the Southwest will start moving towards
TN, continuing a warming and drying pattern for the end of next
week.
&&
.AVIATION...
(00Z TAFS)
Issued at 626 PM CDT Fri Aug 11 2023
High ceilings expected through the overnight hours with calm
winds, which allows for patchy fog across the CSV and SRB area.
TSRA is in place for CKV from 13-15z, and the BNA/MQY region from
15-18z which will drop the visibility. Winds will also increase
during these periods with gusts around 20kt, but potentially a
little more. As the storm moves out, visibility increases and
winds calm and shift SW.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 73 92 74 91 / 10 50 40 50
Clarksville 72 91 74 90 / 10 50 40 40
Crossville 67 85 67 84 / 0 50 50 60
Columbia 72 91 73 91 / 10 40 30 40
Cookeville 69 87 70 85 / 0 50 50 50
Jamestown 67 86 69 84 / 0 50 50 50
Lawrenceburg 70 90 72 90 / 0 40 30 40
Murfreesboro 72 92 73 91 / 0 50 30 50
Waverly 71 90 72 90 / 10 50 40 40
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Rose
SHORT TERM...Mancilla
LONG TERM....Mancilla
AVIATION.....Unger/Gallien
Area Forecast Discussion
National Weather Service Norman OK
556 PM CDT Fri Aug 11 2023
...New AVIATION...
.SHORT TERM...
(This evening through Saturday)
Issued at 257 PM CDT Fri Aug 11 2023
The combination of extreme heat, active fire weather, and severe
potential continues across our area this evening and tomorrow. Heat
indices are clearing well into the 110s across a wide swath of our
area this afternoon, and dangerous heat conditions will persist
until this evening.
Cumulus clouds are slowly developing in the central Texas panhandle
as a pseudo-dryline mixes eastward. These may provide the impetus
for convective development across southwest Oklahoma by 5:00 p.m.
Other chances at storm development will occur this evening in
western north Texas along the dryline, and near a slowly lifting
warm front in northwest Oklahoma. The latest HRRR is only weakly
hinting at storm development, but CAMs have generally been
underconvective this week. MLCAPE values barely over 1,000 J/kg will
be markedly lower than last night, so storm longevity especially
after sunset is in question. However, DCAPE values are as high as
they have been all week - in the 1,600-2,000 J/kg range, driven by
hot, well-mixed boundary layers and dry mid-levels. Damaging wind
gusts up to 70 mph are possible with the strongest cores, as well as
lightning which will likely aid in new fire ignitions in western
north Texas.
After another uncomfortably warm overnight (most areas will fail to
get below 75), we get to run it all back tomorrow for the first day
of the weekend. Storm chances will continue tonight across much of
the area, but particularly northern and central Oklahoma. These will
linger into tomorrow morning. Red flag warnings will continue
tomorrow afternoon in western north Texas as elevated fire weather
continues. ERCs will edge back up toward the 90th percentile with
winds gusting up to about 25 mph from the south and relative
humidities dropping to about 20 percent. Meanwhile, excessive heat
warnings are in effect for most of the Red River Valley, while heat
advisories are in effect for most of central Oklahoma. Upgrades may
be required as the forecast comes more into focus, but for now it
appears mid-70s dewpoints are possible near and east of I-35.
Meister
&&
.LONG TERM...
(Saturday night through next Thursday)
Issued at 257 PM CDT Fri Aug 11 2023
Storm chances will increase early tomorrow night across the
northwestern part of Oklahoma as a wave rounds the subtropical ridge
into Kansas. Instability will be modest at first, but - stop me if
you`ve heard this before - deep, well-mixed boundary layers should
encourage forward propagation of outflow and a damaging wind
threat. These storms will likely encounter richer boundary-layer
moisture across north central Oklahoma just as the LLJ increases
to about 35- 45 knots. The threat for severe weather will likely
be maximized in this corridor early during the overnight period.
Chances for storms will continue to linger into early Sunday
morning, and will leak southward into central Oklahoma.
The best chance for widespread storms in the upcoming period looks
to be Sunday night. A powerful closed low will dip southeastward
into the Upper Midwest, bringing the northern half of our area into
30-40 knots of westerly flow. Heavy rainfall looks like the primary
hazard, especially across the northern half of Oklahoma. Severe
weather looks a bit more uncertain due lower overall instability,
but will be monitored.
After rain chances diminish on Monday afternoon, things do look to
calm down for the rest of next week. That`s going to let us get hot
and humid once more.
Meister
&&
.AVIATION...
(00Z TAFS)
Issued at 521 PM CDT Fri Aug 11 2023
VFR conditions to continue.
Isolated storms will be possible this evening across west and will
include a mention for a couple of hours at CSM, otherwise chances
too low at this time. Will also keep a mention late evening and
and overnight at both PNC/SWO for some activity. Otherwise, light
south/southeast winds and mid/high clouds overnight and through
much of the day Saturday. Southwest winds will increase by mid-
morning across most sites.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 77 101 74 100 / 20 30 20 10
Hobart OK 78 106 74 104 / 30 20 20 10
Wichita Falls TX 82 109 80 108 / 30 10 10 0
Gage OK 71 97 69 96 / 30 40 50 20
Ponca City OK 73 94 73 94 / 40 40 50 30
Durant OK 79 103 80 104 / 0 10 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Heat Advisory until 9 PM CDT this evening for OKZ006>008-011>013-
015>018-021-022.
Heat Advisory from noon to 9 PM CDT Saturday for OKZ007-008-012-
013-018>036-040>043.
Excessive Heat Warning until 9 PM CDT this evening for OKZ019-
020-023>048-050>052.
Excessive Heat Warning from noon to 9 PM CDT Saturday for
OKZ037>039-044>048-050>052.
TX...Heat Advisory from noon to 9 PM CDT Saturday for TXZ083-084-087.
Excessive Heat Warning until 9 PM CDT this evening for
TXZ083>090.
Excessive Heat Warning from noon to 9 PM CDT Saturday for TXZ085-
086-088>090.
Red Flag Warning until 9 PM CDT this evening for TXZ083>090.
Red Flag Warning from noon to 9 PM CDT Saturday for TXZ083>090.
&&
$$
SHORT TERM...04
LONG TERM....04
AVIATION...30
Area Forecast Discussion
National Weather Service Phoenix AZ
428 PM MST Fri Aug 11 2023
.Update...Updated Aviation
&&
.SYNOPSIS...
Afternoon and evening isolated to scattered thunderstorms will
continue through the weekend, primarily across the higher terrain
areas. Temperatures will hover at or slightly below normal across
the lower deserts into early next week. An uptick in thunderstorm
activity early next week is expected to proceed a short-lived
heat wave going through the latter portions of next week.
&&
.DISCUSSION...
Early this afternoon, thunderstorms have begun to develop across
higher terrain areas, particularly east of the metro as well as a
few weak cells over the Table Top Mountains. The latest HRRR would
suggest convection to continue firing along the higher terrain
spots along the western outskirts of the Phoenix metro into this
evening. However, the overall outlook remains mostly the same, as
thunderstorm should remain isolated to scattered in nature into
tonight, with only a locally heavy downpour and lightning being
the threats with any thunderstorm. Synoptic mid to upper level
flow is from the south, with favorable ascent east of the Phoenix
metro from a troughing feature set offshore of central CA.
Advancing through the weekend, moisture levels will be decreasing
due to flow turning more southwesterly as the sub-tropical ridging
retreats back across the northern Gulf of Mexico and the troughing
to the west migrating southeast over the southern CA coast by
tomorrow afternoon. Going into early next week, anomalously high
heights building over the Pacific Northwest will slowly squeeze
the troughing southwestward, with the influence of the ridge
increasing. As a result of this pattern change, southeasterly flow
will begin to develop going into early next week, resulting in
thunderstorm chances increasing once again across southcentral AZ.
Ensembles are currently depicting 1.40-1.60" PWAT`s extending into
southcentral AZ for Monday and Tuesday, which would make this
period one of the highest for PWAT values during the monsoon. At
this time, current thunderstorm chances are around 40-50%
(25-30%) for the higher terrain (Phoenix metro) for Monday and
Tuesday.
Ridging will continue to build across the region through the
middle of next week, resulting in moisture levels to decrease and
temperatures to rise well above normal once again. There remains
some uncertainty as to how quickly conditions will warm due to the
lingering moisture and convective activity (especially on
Tuesday), so no heat products are in effect at this time.
Certainty is higher in Major to locally Extreme HeatRisk across
the lower deserts, particularly southcentral AZ, developing on
Wednesday and lasting into the latter portions of next week.
The forecast outlook becomes much more muddled going into late
week and into next weekend, primarily because global
models/ensembles show a tropical system developing off the central
Mexico coast late next week. The track and strength of this
feature becomes uncertain quickly going into next weekend, as the
more robust GEFS solution brings in substantial moisture into the
region, while the ECMWF keeps moisture levels at or below
climatological normal. Thus, we will have to keep a close eye on
how ensembles evolve over the coming few days in regards to
whether this tropical system comes to fruition and if this system
will have any impacts to the region.
&&
.AVIATION...Updated at 1720Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The main aviation concerns will be convective activity around
terminal locations and abrupt wind shifts due to thunderstorm
outflows. Winds this evening will contain a southerly component
before switching to the E/SE early tonight. Convective activity
is possible (20-30%) in the vicinity of metro terminal locations
through about 03-04Z this evening. Intense outflows (>=30 kts) are
unlikely (10-20%), but some storms may push out weaker outflows
that could lead to sudden wind shifts. FEW-SCT cloud bases around
10-12 kft, along with SCT-BKN high clouds will be present through
the TAF period.
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are expected during the TAF period. Winds at
IPL will be out of the W through tomorrow morning, with some
occasional gusts upwards of 20 kts this evening. At BLH, SW winds
this evening will give way to more S`rly winds through the
remainder of the period. Some occasional mid-level clouds will
filter in during the forecast period.
&&
.FIRE WEATHER...
The best thunderstorm chances will continue to primarily remain
confined across the higher terrain areas north and east of
Phoenix, with chances waning going through the weekend. The
primary threats with any thunderstorms will be gusty erratic
outflow winds, lightning, and localized downpours with the chance
of wetting rains remaining very low at less than 20% for most of
the area. Thunderstorm chances across the lower deserts will
continue to remain low (<20%), but it`s possible to see an outflow
reach the desert floor from distant activity. Thunderstorm chances
across higher terrain will again increase early next week,
particularly Monday and Tuesday. Apart from thunderstorms, winds
will favor familiar warm season patterns. Min RHs will remain
around 15-25%, while Max RHs will generally range around 40-60%
for most areas. Near to slightly below normal temperatures are
expected through the weekend followed by a warming trend by the
early to middle portion of next week with highs once again back
above 110 degrees across the lower deserts.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Young
AVIATION...RW
FIRE WEATHER...Young/Lojero
Area Forecast Discussion
National Weather Service Salt Lake City UT
355 PM MDT Fri Aug 11 2023
.SYNOPSIS...Moisture expected to largely remain in place across
the region into the weekend. This will result in isolated to
scattered precipitation chances across much of the area, generally
during the afternoon and evening hours. Northern Utah will
gradually trend drier for the coming week while moisture remains
in place across the south.
&&
.SHORT TERM (Through 12Z/6AM Sunday)...Forecast region largely
remains placed between a cutoff low along the central California
coast and broad ridging across much of the southern CONUS. As a
result, moisture lingers across the area, with PWATs generally in
the 0.8 to 1.0 inch range per SPC Mesoanalysis. With sufficient
diurnal destabilization ongoing, once again seeing isolated to
scattered convective development, with activity initially somewhat
terrain anchored now pushing off terrain. With the moisture and
instability, mature updrafts have been capable of rainfall rates
in excess of 1 inch per hour, and given slow storm motions, a
flash flood risk will continue into the evening across rain
sensitive areas of central and southern Utah. Further north,
activity is more isolated and a bit higher based in nature, and
will pose some threat of gusty outflow winds accordingly. CAM
guidance continues to largely suggest activity will wane with loss
of daytime heating, though worth noting some of the individual
HRRR runs keep isolated activity a bit further into the overnight
hours across a weak band of forcing roughly along/south of the
I-80 corridor. In any case, expect any of this lingering activity
to be weaker in nature.
On Saturday moisture looks to remain more or less at similar
levels to that of Friday, especially across southern Utah, but the
environment looks to have a bit more PVA as energy works in
through the southerly flow. While still meager, this should help
result in a bit more coverage of convection, especially across
southern Utah. CAMs once again show a fairly typical diurnal
pattern to this convection, with activity firing late morning to
early afternoon, and diminishing through the evening hours. With
efficient rainfall production and slow storm motions once again,
will need to monitor the threat of localized flooding, primarily
in rain sensitive areas.
.LONG TERM (After 12Z/6AM Sunday)...A fairly consistent weather
pattern is setup for much of the extended period as models remain
in agreement on the placement and movement of the passing trough
to our north and growing ridge to our south east. This will
promote daily afternoon/evening showers and storms, particularly
over southern half of Utah where the best available moisture is
present with forecasted values of .8-1.0". The potential for
coverage to move more northward along the Wasatch Front grows
during the work week but storms and showers likely more isolated
at that point. This pattern will keep afternoon highs near
climatological norms but with a slight warming trend as we end the
period.
Model guidance starts to split by midweek on the movement of the
large ridge pattern to our southeast and whether it grows over the
Great Basin or remains in place.
&&
.AVIATION...KSLC...There is low confidence in the wind forecast, but
light, westerly to northwesterly flow will likely prevail through
the afternoon outside of any outflow. Isolated thunderstorms are
likely to develop over the Oquirrhs; these may produce gusty and
erratic outflow winds and may transition KSLC to southerly winds.
Otherwise, southerly drainage flows are expected to return after 03-
04z. There is a 15% likelihood of thunder at KSLC before 02z.
.REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers and
thunderstorms will continue to develop this afternoon, mainly
ceasing after 04z, though some isolated showers may linger until
08z. These storms may produce gusty and erratic outflow winds. VFR
conditions will prevail. Diurnally-driven winds will also prevail
outside of any outflow.
&&
.FIRE WEATHER...Friday`s convection expected to wane moving into the overnight
hours, but moisture will remain across the state on Saturday. As
a result, will see convection once again develop from late morning
through the afternoon hours. By Sunday, northern Utah sees a
gradual drying trend begin, yielding lower precipitation chances
accordingly. Thunderstorms will largely be wet in nature, though
some of the northern Utah activity will be higher based and on the
drier side. From central to southern Utah, moisture looks to
linger into the upcoming week, yielding continued chances of
afternoon convection. Areas with the increased moisture will also
see higher afternoon minimum relative humidity values, as well as
improved overnight recoveries.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&
$$
SHORT TERM...Warthen
LONG TERM...Selbig
AVIATION...Cunningham
FIRE WEATHER...Warthen
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity
Area Forecast Discussion
National Weather Service Las Vegas NV
115 PM PDT Fri Aug 11 2023
.SYNOPSIS...Monsoonal moisture will gradually increase across the
region this weekend through at least the middle of next week leading
to chances for thunderstorms to develop each day...especially over
the mountains.
&&
.DISCUSSION...Through next Friday.
A closed upper level low off the California coast will be the
driving factor over the next few days. This low will continue to
bring a southwest flow to the region today, but it is not expected
to completely dry us out. PWs still remain around 1.00-1.25" with
dew points in the lower to mid 50s across much of the CWA this
afternoon. This moisture combined with weak instability will lead to
a few afternoon showers and thunderstorms over mainly the higher
terrain into this evening. The latest HRRR has also been fairly
consistent over the past few runs indicating at least a slight
chance of thunderstorms impacting the Las Vegas Valley. The greatest
coverage this afternoon is expected to be across northern Inyo
County, especially in the Sierra and White Mountains. This is also
an area that needs to be watched for the likelihood of training
cells. Because of this, WPC has issued a marginal risk for excessive
rain due to the potential of training cells.
On Saturday, PWs remain about the same as today, but we do increase
overall instability. This could lead to a slightly higher coverage
of storms across most of the CWA. With the PWs remaining between
1.00-1.25", there could be some local areas of flash flooding, but
not expecting anything widespread.
Beyond Saturday, the low off the coast will gradually slide back to
the south and then get pushed a bit further off the coast as high
pressure centered over the TX/NM region expands west. This will
allow for more of a southeast flow into the region which will bring
additional monsoonal moisture into the region. The latest models are
not indicating any significant deeper moisture, but enough to help
generate a few showers and thunderstorms each afternoon into next
week. What happens with the off shore low is still in question next
week, but looks to be somewhat of a player through the extended
period. For now, do not see any significant drier air scouring out
the monsoonal moisture so it may remain in place at least until the
middle part of next week. Beyond the extended period, the latest
deterministic models are indicating a tropical system developing
off the southern tip of Baja. Something definitely to keep an eye
on. Temperatures will remain slightly below normal into the weekend,
but jump to a few degrees above normal early next week as high
pressure expands west, but the potential for precipitation and
outflow from storms to provide a cooling effect will be a
possibility each day.
&&
.AVIATION...For Harry Reid...Breezy south or southeasterly winds
with gusts of 10-15 knots are expected through the early evening
with winds shifting southwest and decreasing overnight. Scattered
cumulus with bases near 10k are expected with a slight chance of
thunderstorms through 2z this evening, with gusty winds possible if
thunderstorm activity forms.
For the rest of southern Nevada, northwest Arizona and southeast
California...Numerous thunderstorms are expected near the Sierra and
Owens Valley impacting KBIH with pockets of rainfall and gusty
surface winds. Elsewhere, a few isolated thunderstorms are possible
across southern Nevada and around the Las Vegas Valley with locally
gusty surface winds possible. Otherwise, diurnal wind patterns with
just a few clouds at the remaining TAF sites across the Mojave
Desert and Colorado River Valley.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
DISCUSSION...Gorelow
AVIATION...Meltzer
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