Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/11/21
Area Forecast Discussion
National Weather Service Bismarck ND
1003 PM CDT Sat Jul 10 2021
.UPDATE...
Issued at 947 PM CDT Sat Jul 10 2021
High pressure is situated over western ND this evening and will
slowly propagate south and east overnight. With mainly clear skies
and light winds we lowered temperatures a little over our normally
cool areas along and west of the Missouri River.
Atmosphere has dried significantly in the past 18-24 hours so will
not introduce any fog. There could be some patchy fog in the
normal low spots, but not enough confidence to mention at this
time with dry forecast soundings and cams not hinting at any
significant visibility issues.
We may need to consider some smoke and haze going forward with
smoke from distant fires encroaching on the forecast area over the
next couple of days. So far there have been no reductions in
visibility but satellite indicates an area of smoke over south
central into eastern ND, with smoke aloft approaching from the
west. Will pass this along to the overnight shift.
UPDATE Issued at 527 PM CDT Sat Jul 10 2021
Slight chance pops were to go through 00 UTC, we removed them an
hour early. A few showers were noted over southeast ND and into
northeast SD but with a southward movement, they will remain out
of western and central ND. An isolated shower can not be
completely ruled out central ND with 500-1000 J/KG MLCape and
steep low level lapse rates, but the latest Rap soundings show
quite a bit of mid level capping so convection does not look
favorable. Made some minor adjustments to sky cover, otherwise no
changes to the going forecast.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 230 PM CDT Sat Jul 10 2021
Warm and dry conditions highlight the short term period.
Currently, upper level trough continues to push off to the
southeast, while an upper level ridge builds in from the west.
Surface high pressure moving south across the Dakotas, producing
a light northerly wind. Enough instability and lingering boundary
layer moisture (despite lack of forcing) to trigger a few
isolated showers this afternoon. Opted to add a slight chance for
the afternoon hours.
Upper level ridge axis will continue to move into the Northern
Plains tonight into tomorrow, resulting in a mostly clear sky over
the next 24-36 hours. It will be warm and dry for Sunday, with
highs in the 80s to lower 90s. Will see near critical fire
weather Sunday afternoon across the west, with min RH values
falling into the lower 20s coupled with a steady southerly wind of
10 to 15 knots. Will add this to the HWO.
.LONG TERM...(Sunday night through Saturday)
Issued at 230 PM CDT Sat Jul 10 2021
Ridge is flattened Sunday night by an incoming S/WV. Thereafter,
we will be under a quasi-zonal flow regime Monday through the end
of the week, where we will see, on average, seasonal temperatures
and periodic chances for showers and storms as several embedded
waves move through aloft within the flow.
Extended models continue to strongly suggest a ridge of high
pressure building across the western CONUS and Rocky Mountains
late this period, eventually into our region the following week.
This would support a trend towards hot and dry weather as we near
the last week and a half of July.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 947 PM CDT Sat Jul 10 2021
VFR conditions are expected through the forecast period. Light
northerly winds this evening will diminish overnight and turn
southerly 10-15 knots Sunday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...NH
LONG TERM...NH
AVIATION...TWH
Area Forecast Discussion
National Weather Service Boise ID
901 PM MDT Sat Jul 10 2021
.DISCUSSION...Strong high pressure aloft will remain situated to
our south as dry westerly flow aloft continues over our area
through Sunday. Temperatures will be very hot in the valleys on
Sunday, although highs are expected to be slightly lower. Several
active wildfires throughout the region will continue to deliver
smoke into our area. No updates.
&&
.AVIATION...Mainly VFR. Reduced visibilities from layers of
wildfire smoke. Surface winds: variable 5-12 kts tonight, becoming
W-NW 10-20 kts Sunday afternoon. Winds aloft at 10k feet MSL:
W-SW 5-15 kts. Density altitudes will remain high due to hot
temperatures.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Monday night...The weather story
will continue to be dominated by heat, dry conditions, and smoke
into early next week. Temperatures will remain 10-15 degrees above
normal each day, with high pressure parked to our south and dry
westerly flow aloft over the region. Overnight temperatures will
remain well above normal as well making for dangerous conditions.
An Excessive Heat Warning is in effect through Monday afternoon.
Smoke from area wild fires will keep the skies hazy, with some
mixing to the surface. The latest forecasts from the HRRR Smoke
Model keep the majority of smoke aloft, but there is an
expectation that air quality will be reduced into early Monday.
LONG TERM...Tuesday through Saturday...Conditions will remain hot
and dry as a strong upper-level ridge resides over the western
U.S. This will keep temperatures 5-10 degrees above normal, just
shy of record values. Dry west to southwest flow aloft will hinder
monsoon moisture from reaching southwest Idaho and southeast
Oregon and keep the probability of thunderstorms low.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Excessive Heat Warning until 9 PM MDT Monday IDZ012>016-030-033.
OR...Excessive Heat Warning until 9 PM MDT /8 PM PDT/ Monday
ORZ061>064.
&&
$$
www.weather.gov/Boise
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise
DISCUSSION...BW
AVIATION.....AL
PREV SHORT TERM...MC
PREV LONG TERM....SH
Area Forecast Discussion
National Weather Service Cleveland OH
948 PM EDT Sat Jul 10 2021
.SYNOPSIS...
Surface low pressure over the Mid Mississippi Valley will drift
northeast to southern Lake Michigan through Sunday. As a
result, a warm front will lift north toward the area tonight.
This warm front will be north of Lake Erie by early Monday
morning. The low will slowly move north across the Upper Great
Lakes through Tuesday while high pressure builds northeast to
the Ohio River Valley.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
Minimal changes have been made to the forecast for the remainder
of the overnight. Showers/thunderstorms moving east and
northeast Indiana and southwestern Ohio this evening. This
timing is very close to tweaks made earlier. Otherwise only
made some minor changes to temperatures to reflect current
trends.
Previous Discussion...
Quiet weather will slowly fade as drier air will be displaced by
warm and humid air by Sunday. A positively tilted wave over the
northern PLains is expected to deepen and evolve into the close
elongated low from southern Wisconsin to northern Missouri by
Sunday morning. Southwest flow ahead of the this feature and
surface low tracking northeast will allow a warm front to move
across the forecast early Sunday. Precipitable water values were
around 0.5 across northern Ohio and northwest Pennsylvania.
However, higher values around 2 inches over the Mid Mississippi
Valley and southwest flow will bring in this moisture across the
forecast area affection southwest and western zones before
sunrise Sunday morning and the rest of the forecast area during
the day. Expected precipitable water values to increase up to
1.9 inches late Sunday morning. HRRR has precip west I-71 by
Sunday morning. As a result, will bring in rain chances across
the west before sunrise and persist categorical pops through
Sunday. Limited mid layer instability will be in play until the
surface warm front sweeps north across the forecast area late
Sunday morning. Surface cape values area expected to increase to
1000 to 1200 j/kg after the warm front...mid day Sunday and
Sunday afternoon. With the orientation of the warm...training of
convection is not expected with general amounts of half inch
and isolated 1.5 inches on Sunday. Therefore, WPC has updated
the forecast area to marginal risk. However, heavy rainfall is
possible with very efficient rainfall processes but should
remain isolated. We are a little concern with 0-3km helicity
values approaching 350m/s ahead of the warm front especially
over northeast Ohio and northwest Pennsylvania Sunday morning.
LCL are forecast to drop from 1500 to 500ft. Both features lifts
northeast before the surface base instability. Will monitor the
evolution and intersection of all three features on Sunday.
Elevated rain chances will persist Sunday night as scattered
showers and thunderstorms Sunday night into Monday morning can
be expected given the ample low-level moisture present. Lows
tonight will drop into the upper 50s to mid 60s across the area.
Highs Sunday will generally be in the upper 70s to low 80s.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
On Monday, an upper level trough over the central US and associated
surface low lingering over the Missouri Valley will become more
progressive, lifting northeast throughout the short term. With the
relative location of northeast Ohio/ northwest PA to the low
pressure, the area will remain under the warm sector with ample WAA
and moisture advection across the area. By Monday afternoon, daytime
heating will allow for instability values to increase to near 2000
J/kg. This should allow for a decent coverage of showers and
thunderstorms over the area, with current models keeping the
greatest forcing to the west where the upper level jet is located.
PWATS are expected to be near 2 inches which will allow for
localized heavy rainfall. As a result of this set up, SPC has Ohio
and NW Pennsylvania in a Day 3 Marginal Risk for severe weather.
With the airmass maintaining tropical characteristics, WPC has also
issued a Day 3 Marginal Risk for excessive rainfall. The evolution
of this system on Monday will need to be monitored for the potential
of severe weather. High temperatures will reach into the mid 80s
with dewpoint temperatures in the 70s.
By Tuesday, the center of the low is expected to be positioned over
the northern Great Lakes, extending a cold front south across the
Midwest. The general upper level flow weakens and becomes more
broad, which will limit any upper level support for shower
development. However, daytime heating and the frontal passage should
provide decent support to get afternoon shower and thunderstorm
development. The evolution of the low pressure system to the west of
the area will be key in storm potential on Tuesday. High temperature
on Tuesday will be a bit cooler in the low to mid 80s with
conditions remaining muggy. Overnight lows through the period will
be in the upper 60s to low 70s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
On Wednesday, a broad upper level trough persists across the north
US with embedded shortwaves. Models are not consistent in timing of
these embedded troughs impacting the area so confidence in timing
and location of precipitation remains fairly low on Wednesday.
Southwesterly flow will allow for moisture to continue to be
advected across the area. As a result, have opted to keep chance
PoPs for much of the area, especially with the continued chance of
daytime heating enhancing instability and promoting shower and
thunderstorm development.
On Wednesday night, models are pretty consistent with a low pressure
developing over the north central US with an associated surface low.
General flow should take this system east to northeasterly north of
the Great Lakes. As a result, a cold front will likely move across
the area Thursday night into Friday, however exact timing remains
uncertain at this time. The biggest concern is with the progression
of this boundary for the end of the work week/beginning of the
weekend. Models are continuing to trend towards it stalling as a
stationary boundary oriented east/west somewhere across Ohio.
Persistent showers may result along this boundary which could pose a
late week flooding concern. Overall, the systems in the long term
will need to continue to be monitored for any threat of severe
weather or flooding.
High temperatures through the period will generally be in the 80s
with overnight lows in the 60s. Dewpoints are expected to remain in
the upper 60s to low 70s, so muggy conditions are expected to stick
around for now.
&&
.AVIATION /00Z Sunday THROUGH Thursday/...
VFR conditions are expected through much of the night as we
await the arrival of a warm front into at least central Ohio by
sunrise. There are some sprinkles from KMFD to KCAK to KYNG but
these should dissipate/end by 02z. Will then watch for gradually
lowering ceilings overnight as showers/thunderstorms spread to
the north and east across the region. Dont think we will see any
MVFR ceilings until the rain arrives after 09Z. There will then
likely be pockets of IFR with the heavier rainfall that could
lift across the entire region through the morning, not clearing
NW PA until early/mid afternoon.
Light winds overnight become east 8 to 12 knots by sunrise then
continue through 18Z. Higher gusts could occur near the thunderstorms.
Outlook...Non-VFR possible in showers and thunderstorms Sunday
aftn/eve through Wednesday.
&&
.MARINE...
High pressure over the Great Lakes region has allowed a generally
weak east-northeasterly flow across Lake Erie. This winds will
generally increase to 10-15 knots as an upper level trough
approaches the region tonight into Sunday. The strongest winds will
be ahead of the warm front on Sunday, approaching 20 knots at times.
This will result in waves building to 2-4 feet in the western basin,
however these should remain mostly over the open water and along the
far western coast so have opted to not issue a Small Craft for any
of the lakeshore at this point.Winds will gradually veer behind the
warm from that will move north across the lake Sunday night,
becoming southwesterly at 5-10 knots on Monday. The winds will
increase on Tuesday to 10-15 knots as a cold front and associated
tighter pressure gradient approaches from the west. The strongest
winds will be in the western basin again, however offshore flow will
keep the largest waves north of the area. The general flow across
the lake will persist through much of the week and no marine
headlines are anticipated at this time.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...FZ/MM
NEAR TERM...FZ/MM
SHORT TERM...Campbell
LONG TERM...Campbell
AVIATION...MM
MARINE...Campbell
Area Forecast Discussion
National Weather Service Dodge City KS
1022 PM CDT Sat Jul 10 2021
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
Issued at 1022 PM CDT Sat Jul 10 2021
WV imagery indicates a northwest flow aloft prevailing across the
Western High Plains. Near the surface, high pressure is sinking
slowly southward across the Northern Plains.
&&
.SHORT TERM...(This afternoon through Sunday night)
Issued at 1200 PM CDT Sat Jul 10 2021
Cooler, drier and more stable air was in the process of filtering
into SW Kansas at midday, behind this morning`s initial cold
front. The process is slow at first, with radar imagery showing
various reinforcements of the new airmass still arriving.
Northerly wind fields will organize this afternoon, averaging
15-25 mph. Despite this, the atmosphere will still be warm enough
to support max temperatures within a few degrees of 90 (about a 10
degree reduction from Friday). All models including the HRRR and
the 12z NAM show convective redevelopment on the frontal boundary
occurring southeast of SW Kansas, and all pops have been removed
this afternoon through tonight.
The cooler drier air mass will be reinforced through tonight, with
12z NAM depicting a weak 1020 mb surface high near Goodland by
7 am Sunday. As such a light north wind will continue through the
night, and with precipitable water (moisture in the atmospheric
column) continuing to decline, radiational cooling will deliver
the coolest night we have seen in quite some time. Dewpoints will
also trend down with time, and lowered sunrise Sunday temperatures
several degrees into the upper 50s at many locations. Open the
windows tonight for the free air conditioning! Some short term
models suggest some stratus may enter the northeast zones late
tonight.
A 576 dm closed low is projected by guidance to hang out near
northeast Missouri all day Sunday. On the back side of this
cyclone, the cooler/drier air will be reinforced by a shortwave
rotating southward. 12z NAM/GFS both show another 3-5C degrees of
cooling at 850 mb versus Saturday, supporting afternoon
temperatures only in the lower to mid 80s. Some MOS guidance is
cooler than this, but out of respect of the mid July sun stayed
above the coolest guidance. Some mid level clouds will be mixed
with the sunshine at times, and as midlevel temperatures cool a
few degrees, can`t rule out a stray sprinkle or light shower as
ECMWF suggests. Kept forecast dry.
.LONG TERM...Monday through Saturday)
Issued at 200 PM CDT Sat Jul 10 2021
On the eastern periphery of the Great Basin subtropical high, it
doesn`t take long to warm right back up to normal on Monday, with
afternoon temperatures in the lower 90s. Additional warming is
expected Tuesday, as heights/thickness climb and elevated south
winds supply mixing, with mid to upper 90s expected.
Wednesday and Thursday, high pressure weakens over the Desert SW,
as a shortwave dives through the northern plains. An attendant
weak boundary is probable somewhere in/near Kansas during this
time. 12z GFS is wetter and cooler during this time, with some
suspicious looking spurious shortwaves, while NBM guidance and
12z ECMWF show little if any cooling (continued afternoon
temperatures in the 90s). Low grade pops from the NBM for
Wednesday and Thursday are an acceptable compromise for now. By
next weekend, ECMWF shows the upper high reestablishing over the
Rockies, but continued northerly flow on its eastern periphery
should keep at least small thunderstorm chances going.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 612 PM CDT Sat Jul 10 2021
A surface boundary will work its way across southwest Kansas
tonight. Behind this boundary an area of low level moisture in
the 2000 to 3000ft AGL level is forecast to spread across the Hays
area between 09z and 15z Sunday. Otherwise BUFR soundings
indicating VFR conditions over the next 24 hours. The winds
overnight will be north northeast at 10 knots or less. The
north northeast winds will increase to 10 to 15 knots after 15z
Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 59 85 59 92 / 10 0 0 0
GCK 59 85 58 91 / 0 0 0 0
EHA 60 86 60 93 / 0 0 0 0
LBL 61 87 60 94 / 0 0 0 0
HYS 60 81 57 89 / 0 0 0 0
P28 63 85 61 91 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJohnson
SHORT TERM...Turner
LONG TERM...Turner
AVIATION...Burgert
Area Forecast Discussion
National Weather Service Duluth MN
642 PM CDT Sat Jul 10 2021
.DISCUSSION...(This evening through Friday)
Issued at 332 PM CDT Sat Jul 10 2021
Dry weather will continue through the weekend with smoky skies
across much of the Northland. Temperatures will be just a touch
above average for much of the forecast period. Next chances for
precipitation arrive Tuesday into Wednesday.
Today has been a calm, clear day across the region, and we are
expecting a similar day tomorrow. Smoke from Canadian wildfires has
begun to drift southward across the International Border and will
impact the Northland through the rest of the weekend. Hazy
conditions are possible this evening, but more apparent near-surface
smoke continues to seem likely Sunday afternoon as a northeast
breeze over Lake Superior advects it into MN and WI. There is an Air
Quality Alert in effect for much of NE MN for fine particle
pollution which is expected to reach levels unhealthy for sensitive
groups.
Our next chance for precipitation arrives Tuesday into Wednesday.
The upper low slowly swirling to our south will begin to move
northeastward, putting NW WI in the northwest quadrant of the
surface low. At nearly the same time, a cold front associated with
an upper level trough shooting eastward out of the PNW will begin to
cross over northern MN. There is still some disagreement amongst the
global models regarding the exact magnitude and spatial extent of
these disturbances, so we have left broad precipitation chances
across the region for much of Tuesday and Wednesday at this time.
Embedded thunderstorms are possible but no widespread severe weather
is expected at this time. Some lingering showers are possible into
Thursday morning before we end the week dry on Friday. Much of the
Northland is currently 3"-6" below normal annual precipitation so
any rainfall would be greatly appreciated.
Temperatures through next week will be generally a couple degrees
above normal with highs in the 80s. Winter-lovers beware - there is
a slight chance for another round of excessive heat with highs in
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 642 PM CDT Sat Jul 10 2021
VFR conditions are expected for most areas through the period
thanks to high pressure. Winds will be relatively light, less than
10 knots. There will be some visibility issues with smoke/haze
from the Canadian wildfires. We leaned on the HRRR and have a
mention of 5-6sm visibilities in haze at times through the period.
There could be some lower values in fog, mainly at KHYR tonight.
&&
.MARINE...
Issued at 332 PM CDT Sat Jul 10 2021
Conditions over Lake Superior will be quiet and calm overnight this
evening into Sunday with light and variable winds. Smoky skies are
likely over much of western Lake Superior at least through late
Sunday night. Northeast winds 10-15 knots build over the lake Sunday
afternoon, which may lead to waves up to a foot or two at the head
of the lake near the Twin Ports and around the Apostle Islands. No
hazards are expected, though beach-goers along Park Point and
Wisconsin beaches should stay aware of current wave conditions in
case afternoon winds become more gusty that the current forecast
indicates, which could lead to a moderate swim risk. Winds will ease
overnight before the northeast breeze picks up again Monday, with
the same effect around the Twin Ports and Apostle Islands.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 58 83 56 81 / 0 0 0 10
INL 57 90 60 89 / 0 10 0 10
BRD 57 86 57 86 / 0 0 0 0
HYR 51 84 54 83 / 0 0 10 20
ASX 52 81 54 80 / 0 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
DISCUSSION...Levens/Huyck
AVIATION...Melde
MARINE...Levens/Huyck
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
646 PM CDT Sat Jul 10 2021
.AVIATION... /11@00Z TAFs/
SHRA continued to move to the north across our area and have gone
with VCSH at the TAF sites for the next couple of hours until
dissipation due to sunset and loss of heating. A surface boundary
will move into Central Texas by Sunday evening with SHRA/TSRA along
it. Although the best chances are at KAUS, have left mention out as
PROBs are still low. Later forecasts will monitor model and radar
trends for possible mention. VFR flying conditions turn MVFR late
evening into overnight. KSAT/KSSF should have a few hours of IFR and
have maintained mention. CIGs rise on Sunday to VFR by midday. S to
SE winds 5 to 12 KTs prevail with the highest winds this evening and
on Sunday when a few gusts to 25 KTs are possible.
&&
.PREV DISCUSSION... /ISSUED 245 PM CDT Sat Jul 10 2021/
SHORT TERM (Tonight through Sunday Night)...
Visible satellite imagery and RAP analysis indicate that there`s
very little definition left (at the surface nor aloft) to the system
that brought scattered to numerous showers and locally heavy
rainfall over much of the past week. However, continued
southeasterly flow in the PBL has us in a very moist airmass
characterized by dewpoints in the 70s and even lower 80s at times,
although the sensors may be running erroneously hot at a couple of
these sites such as DLF. Temperatures reach the 80s and lower 90s
today, which combined with the humidity will allow for pockets of
100+ degree heat indices. In addition, a few showers will continue
through the early evening with the best coverage over the south half
of the area.
The loss of daytime heating should shut things down quickly around
sunset. Can`t rule out a few rumbles of thunder through this
evening, and isolated shower activity could continue into the early
overnight along the Rio Grande, but chances are low. With ample
moisture hanging around, seasonal lows are expected and clouds will
redevelop. They should scatter out as usual prior to midday Sunday,
and a slightly warmer day will be in store with highs forecast to
reach the upper 80s to mid 90s. Again, some locations could see 100-
105 degree heat indices, primarily along and east of I-35.
A seasonally anomalous trough will be digging southward through
the central-eastern CONUS, and will attempt to send a cold front our
way by Sunday evening. However, it will stall just to our north
overnight before fizzling out. That said, there could still be some
thunderstorm activity that pushes into our northern counties on
Sunday evening through early Monday morning. The HRRR and WRF-FV3
depict a southward progression of this activity into much of the
Hill Country and Austin metro (with the FV3 unrealistically early at
a 21-22Z arrival), but remaining CAM/regional guidance keeps these
storms along our northern border before fizzling. Tend to trust the
slower and less robust NAM at this time. The latest SPC Day 2
Outlook does clip far northern Llano and Burnet counties with a
Marginal Risk for damaging winds. Will continue to monitor trends
over the next 24 hours.
LONG TERM (Monday through Saturday)...
The upper trough over the eastern US will begin to lift out to the
northeast Monday allowing the subtropical ridge to strengthen a bit
over Texas. The low level flow will continue to be from the southeast
keeping the boundary layer warm and moist. These general conditions
will continue through the long term period. The upper ridge will
suppress convection over most of our CWA through the period. However,
across the southeast and east where moisture is deepest there will be
low chances for showers and thunderstorms. This convection will be
diurnally driven with rain possible during the afternoons and early
evenings. Models are showing somewhat lower PW values and any
rainfall should be moderate.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 75 94 75 92 73 / 10 - 20 20 -
Austin Bergstrom Intl Airport 74 93 75 92 72 / 10 - 20 10 -
New Braunfels Muni Airport 74 93 74 93 73 / 10 - - 10 -
Burnet Muni Airport 73 91 73 91 72 / 10 10 30 20 0
Del Rio Intl Airport 76 95 76 95 74 / 10 10 - - -
Georgetown Muni Airport 74 93 74 92 73 / 10 10 30 20 -
Hondo Muni Airport 74 91 74 91 72 / 10 - - - -
San Marcos Muni Airport 74 93 74 93 73 / 10 - - 10 -
La Grange - Fayette Regional 76 94 76 92 75 / 10 - 10 20 -
San Antonio Intl Airport 75 91 75 91 73 / 10 - - 10 -
Stinson Muni Airport 75 92 76 92 75 / 10 - - - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...04
Long-Term...Platt
Area Forecast Discussion
National Weather Service Grand Rapids MI
1053 PM EDT Sat Jul 10 2021
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 252 PM EDT Sat Jul 10 2021
- Risk for thunderstorm with heavy rain into Tuesday
- Strong to Severe storms possible Wednesday night into Thursday
&&
.UPDATE...
Issued at 1054 PM EDT Sat Jul 10 2021
Overall our on-going forecast looks fine. I made some minor
changes, like taking the mention of thunderstorms out of the
forecast through the night as there is not enough instability. I
did not significantly change our probability of rain through nor
did I change our temperature forecast.
The area of precipitation is developing under the area of best 700
to 300 mb Q-Vector convergence. The RAP model shows two area, both
of which match very nicely to our current IR and Water Vapor loops
showing there the cold cloud tops (IR) and mid and high level
moisture is pooling (Water Vapor). The area closest to MI at 02z
was centered over southern Lake Michigan and over time it rotates
toward GRR by mid morning Sunday. It strengthens over the next few
hours but weaken s after it gets north of I-94 toward morning.
There is currently some limited dry air below 850 mb but that
should be taken care of but the lift related to developing upper
level system. There is a trowal associated with the area of
Q-Vector convergence that lifts north with it tonight into Sunday.
The lift in the trowal is not all that great but there is 1.5 to
1.8 inches of precipitable water to work with. So, it woulds seem
as shown by the 00z HREF the area of rain will in fact lift north
with time and reach I-96 by mid morning. Still I do not see any
heavy rain in our CWA the rest of the night into at least mid
morning Sunday. The latest HRRR does show an area of 1 to 2 inches
of rain west of US-131 and south of GRR developing during the
morning so we may have some issues with heavier rain after sunrise
Sunday that we will have to monitor.
&&
.DISCUSSION...(This evening through next Saturday)
Issued at 252 PM EDT Sat Jul 10 2021
- Risk for thunderstorm with heavy rain into Tuesday
Models continue to show a deeper southwest flow developing tonight
and persisting into Monday. This will draw up an unseasonably
moist airmass with PWAT values making it to at least 1.75 inches.
Instability advects in as well so we could see some storms
around...mainly Sunday into Tuesday. However there are some
indications that the excessive rain risk may be lower than
previously forecast. The low level jet trending further east and
is no longer aimed at the CWA. Usually this would also push the
focus of the heaviest rain further east. Also the mid level low
lifts north northeast through the Western Great Lakes region
Monday into Tuesday. With the best height falls over that part of
the region...this would also act to focus a second area of heavy
rain there. It appears the best chance for storm with heavier rain
would be Monday afternoon into the evening if a shortwave could
track through the CWA during the most unstable part of the day.
Locally heavy swaths of rain could result then. As for the severe
weather potential...deep layer shear does not look that impressive
at this time...thus the risk for organized convection looks
limited. Stronger pulse storms would be the main concern at this
time.
- Strong to Severe storms possible Wednesday night into Thursday
Latest model trends show a stronger low level jet moving in from
the southwest Wednesday night and pushing east of the CWA on
Thursday. The associated mid level wave tracks eastward through
the Great Lakes Region. With modest instability show and
increasing deep layer shear some organized convection looks
possible. However the timing of the low level jets arrival at
night may limit the overall severe weather risk. Timing changes on
the arrival of the wave could alter the organized storm risk.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 635 PM EDT Sat Jul 10 2021
A storm system from the Central Plains is expected to move into
the southern Great Lakes overnight. There are some questions as to
just how far north the rain shield from this storm gets Sunday.
Some models or even different hourly runs of the same model like
the HRRR/RAP either show heavy rain as far north as I-96 and
others not so much. The 15z run of the SPC SREF plumes shows 1/3
of the 27 members giving nearly no rain at GRR Sunday. Yet another
1/3 haver over a half inch of rain. The glitch is just how the
upper low and associated surface low move in this weak upper flow
pattern. There is a digging jet on the back side of the upper
level system yet so it should dig south into Sunday. We are just
not sure how far it will get.
If the drier version of life prevails, you will see VFR
conditions will prevail at all of our I-96 TAF sites through
Sunday with NO RAIN at all. It does seem to this forecaster the
moisture/rain should get as far north so that rain should impact
I-94 by mid morning Sunday. In the dry version of this, it would
more so be sprinkles than any impactful rainfall, even for the
I-94 TAF sites. It would be questionable if the MVFR cigs could
even get that far north Sunday.
If the wetter solutions prevail, then expect solid IFR cigs with
strong east winds at the surface (15 to 25 knots gusting to near
35 knots). There would also be a steady moderate to heavy rain
over the entire I-96/I-94 corridor for a good part of the day time
on Sunday. Still, do not expect much in the way of thunderstorms.
For now, not begins totally sure how this will play out, I have
mostly light rain at all TAF sites (the instability for
thunderstorms is more toward I-80 tomorrow). I based the TAFS on
the SPC SREF plumes. Remember it shows 2/3rds of the members
having rain at all TAF sites Sunday. I played the odds that favor
the dominant solution, which is rain. I-94 is more likely to see
at least some rain Sunday and more likely to get IFR cigs at some
point during the day. With the system center tracking south of
this area Sunday, it will be hard to clear the low clouds out once
they move in.
No matter what it will be cloudy all day Sunday. Cloud based will
be no higher than around 5000 ft, with east winds of at least 10
to 20 knots with gusts to near 30 knots at times. Expect layered
to nearly solidly clouds from at least 5000 ft to over 30000
feet. The freezing level is near 13000 ft for tomorrow, so expect
significant icing above that level. Not the best of all possible
days to fly for sure.
&&
.MARINE...
Issued at 252 PM EDT Sat Jul 10 2021
An easterly flow will strengthen later tonight and on Sunday.
Gusts over 20 knots look likely mainly for central and southern
zones. Wave heights will be limited given the offshore component
so no Beach Hazards needed at this time. Another wind and higher
wave event looks likely for later Wednesday into Thursday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory from 2 AM to 5 PM EDT Sunday for LMZ844>847.
&&
$$
UPDATE...WDM
SYNOPSIS...MJS
DISCUSSION...MJS
AVIATION...WDM
MARINE...MJS
Area Forecast Discussion
National Weather Service Indianapolis IN
1143 PM EDT Sat Jul 10 2021
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1122 PM EDT Sat Jul 10 2021
Radar and HRRR reflectivity progs support convection decreasing
from southwest to northeast overnight. No flooding reported and MRMS
radar QPF estimates were only showing a thin band of greater than 2
inch amounts. With that in mind and after coordinating with PAH, LMK
and ILX, dropped the Flash Flood Watch that was set to expire at 8
AM.
&&
.Short Term...(This evening through Sunday night)
Issued at 307 PM EDT Sat Jul 10 2021
Short Term Highlights...
...Heavy rain, flash flood, and isolated severe weather potential
for southern/SW counties of central Indiana...
...Showers and thunderstorms become more widespread late afternoon
and tonight for rest of central Indiana...
...Storms become scattered on Sunday but still brief heavy rain...
Conditions are relatively quiet at this time over central Indiana
with just isolated showers, but this is about to change. Currently,
the effective warm front is harder to discern across IL into
southwest IN, with convective boundaries from morning convection
still in play across the lower OH and mid MS Valleys. Latest
mesoanalysis data reveals surface-based CAPEs from 2500-3500 J/kg
(and MLCAPE 1500-200 J/kg) from southern MO eastward through central
KY, with an instability gradient near the OH River/southern IN, a
sign of the existing warm frontal boundary. Meanwhile, effective
shear is running around 30 kts, enough for storm organization. With
forcing along low-level boundaries and support from the southern
tail of the earlier MCV now over western IL, convection has already
begun to fire over central IL back to STL. Additional development
will occur quickly late this afternoon and head east into central IN
and points south.
While the greatest instability will remain south of our forecast
area (latest HRRR shows this well), there is enough existing
instability (500-1000 J/kg) over our southern counties and about 500
J/kg farther north for convective cells to maintain themselves as
they move across central IN late this afternoon and evening. Matter
of fact, the modest instability in our area will result in shallower
convection but highly efficient rainfall production with effective
collision-coalescence (warm cloud) processes in play. The rain will
pass across the current Flash Flood Watch area, so will maintain the
Watch as is in space and time (til 12 UTC Sunday) for the time being.
Meanwhile, the strong/severe convection that develops late this
afternoon to our south and west (within/near the max instability
axis) should slide ESE or SE. Latest HRRR actually shows bowing
structures in its reflectivity forecast from SE MO into KY, which
makes sense as DCAPEs and low-level lapse rates are quite conducive
for this to our south and west, but cannot preclude this (isolated
wind damage) completely in our southern counties by any means.
Later this evening and overnight, rain and embedded convection from
the MCS will continue to cross central IN, and an interesting
possibility could evolve. This is some hint that there could be a
secondary precip max (the first one associated with the intense
convection to our south) over our central and/or northern counties
of central IN, associated with what looks like a deformation zone-
like setup just north and east of a mid-level shortwave or what
could become an MCV within the MCS. Will have to monitor that and
how that affects precip coverage and amounts, and whether that could
result in heavy rain and any flood concerns north of the current
Flash Flood Watch. No Watch expansion at this time, but will monitor
this tonight to see how things evolve.
On Sunday, most of the rain and convection will have existed central
IN to the northeast. This should leave a relative lull in precip
although low clouds should remain for awhile, but some breaks of
sunshine may develop during the day in the wake of the precip. As a
result, enough warmth, moisture transport, and instability will
exist within a deep S to SW flow pattern aloft ahead of a closing
off mid-level low over the mid MS Valley to produce at least
scattered afternoon convection across central IN, some with brief
heavy rain.
Temp-wise, expect lows tonight basically from 65-70 unless rain
cooled slightly below that, with afternoon highs Sunday in the upper
70s and lower 80s depending on cloud cover trends (slightly higher
if even afternoon sun).
&&
.Long Term...(Monday through Saturday)
Issued at 307 PM EDT Sat Jul 10 2021
Ensemble means suggest an upper low, initially over the Midwest,
will lift off to the northeast early in the extended. However, it
appears a piece of this upper low may hang back across the area for
most of next week.
As the upper low begins to move away, convective potential should
diminish some by early next week. However, with a weak upper trough
axis hanging back across the local area, will keep some PoPs in the
forecast for much of next week.
The ensembles suggest another disturbance may move into the area
from the northwest later next week, around Thursday into next
Saturday. May increase the PoPs towards the end of the extended to
cover the enhanced convective potential with this next wave. Long
range operational models suggest precipitable waters near or in
excess of 2 inches may accompany this feature, so heavy rainfall may
become a threat late next week.
&&
.Aviation...(06Z TAF Issuance)
Issued at 1142 PM EDT Sat Jul 10 2021
IMPACTS:
-Trends and GFS LAMP support mostly IFR ceilings through 17z or so.
-Pulled thunder mention with little recent lightning strikes.
DISCUSSION: Showers will decrease in coverage overnight. There could
possibly be an isolated brief thunderstorm, but chances too low to
mention with instability dropping off. Poor flying conditions with
low ceilings will be the main concern through Sunday morning.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...MK
Short Term...Funk
Long Term...JAS
Aviation...MK
Area Forecast Discussion
National Weather Service Louisville KY
1127 PM EDT Sat Jul 10 2021
.Mesoscale Update...
Issued at 1110 PM EDT Sat Jul 10 2021
Strong leading line convection is making its way into the I-65
corridor in KY, and finally starting to weaken. In the next couple
hrs southern Indiana and north-central KY will catch a break in the
action for the next few hrs. Will clip most of our Indiana counties
out of the Flash Flood Watch.
However, an east-west line is setting up back into southern
Missouri, with a moisture-rich air mass (PWAT exceeding 2 inches)
that has not been worked over. While convection is pushing steadily
eastward, we could see repeated bouts of heavy rainfall overnight in
south central Kentucky. Therefore we will expand the Watch to the
south and east for the rest of the night.
Issued at 904 PM EDT Sat Jul 10 2021
Initial convective band that affected the region earlier continues
to push northeastward through northeastern KY. This convection will
pose a threat of heavy rainfall and gusty winds to our northeastern
Bluegrass counties over the next hour.
Upstream convection continues across southwestern IN and into
northwestern KY. Latest mesoanalysis reveals that MLCAPE values
continue to decrease with the loss of heating. Values are generally
in the 1200-1700 J/Kg range. Nocturnal low-level jet axis has
picked up a bit, so environmental shear values are in the 25-30kt
range. Convection should continue to push eastward and
southeastward with time over the next 1-2 hours. Main threats with
this activity would be heavy rainfall, gusty winds (40-45 MPH), and
cloud to ground lightning.
Highest risk of severe storms looks to be confined to our
southwestern CWA over the next 2-3 hours. This is where slightly
higher amounts of MLCAPE reside and this area hasn`t been worked
over from previous convection. Portions of
Ohio/Butler/Logan/Grayson counties could see some stronger storms as
this line passes through. Some training of cells is possible and
that could result in some flooding issues. Latest 1hr FFG values
are up around 2.3-2.5 in/hr with 3h FFG values up near 3-3.1 in/hr
in these areas. Last few runs of the HRRR have been targeting this
area with strong storms and heavy rainfall.
Issued at 756 PM EDT Sat Jul 10 2021
Convection continues to lift northeastward into southern and
southeastern Indiana this evening. Overall, the convection remains
generally sub-severe, though a few storms did pulse up and required
some warnings given velocity signatures. A relative lull in the
activity is currently being seen across portions of north-central
and east-central KY. Within the broad warm sector, just a few
scattered storms have developed near the Bowling Green area.
Atmosphere remains unstable with MLCAPE values between 1500-2000
J/Kg. Low-mid level lapse rates have fallen off a bit with rates
generally between 5.5-6.2 C/Km. Effective shear values generally
remain below 25 knots. Currently, strongest effective shear resides
just north of the CWA.
We continue to watch an arcing line of convection coming into
southwest Indiana this evening. This activity is getting ready to
push into the Evansville area. This activity continues to push
eastward at about 35 knots and the overall appearance supports that
is mainly cold pool driven at this point. Ongoing and previous
convection out ahead of this line has helped stabilize the
atmosphere somewhat. However, gusts to 50-55 MPH with this line
look possible over the next 1-2 hours before the boundary layer
become more stable and instability wanes due to loss of heating.
Strong moisture flux continues out ahead of this line where mid 70
dewpoints were located. PWAT values are in the 1.9-2.2 inch range.
So while the line may produce less in terms of severe weather, heavy
rainfall is very much likely and with storms moving over the same
areas that have already received rainfall, isolated to scattered
flooding concerns may become the main weather hazard over the next
several hours, especially across far NW KY and southern IN.
Issued at 618 PM EDT Sat Jul 10 2021
Surface warm front continues to lift northward into southern Indiana
early this evening. Just behind the frontal boundary an arcing line
of convection extends from near Jasper, Indiana southeastward
through Fort Knox and then down towards Lancaster, KY. Convection
in this line is fairly strong with a few cells that were strong
enough to warrant a warning or two. Atmosphere is relatively
unstable with MLCAPE values in the 1500-2500 J/Kg range and low-
level lapse rates around 7C/km. Effective shear values remain very
low with speeds of less than 20kts. PWAT values are near 2 inches
and tongue of moisture laden air with dewpoints in the mid-70s is
surging into southwestern KY (mainly west of the Natcher Parkway).
Ongoing convection should continue to move off to the northeast over
the next 1-2 hours. Main threats here will be torrential rainfall,
cloud to ground lightning, and wind gusts of 40-45 MPH though some
locally higher gusts can`t be ruled out with stronger cores. As
this convection moves on off to the northeast, we will get into
another possible precipitation lull for the early evening hours with
just some scattered storms being possible within the warm sector.
Attention will then turn to an area of convection out toward the
Mount Vernon area of southern Illinois where a cluster of
strong/severe storms is ongoing. Last few runs of the high
resolution models bring this activity into our western areas later
this evening.
&&
.Short Term...(This evening through Sunday)
Issued at 315 PM EDT Sat Jul 10 2021
...Stormy Weekend, Locally Heavy Rainfall and Severe Weather
Threat...
Latest sfc analysis reveals sfc low pressure over MO/IL, with a warm
front extending across southern IN and eastern KY. Mosaic radar
shows convection initiating across the I-64 corridor near St. Louis.
CAMs have been consistent on pushing this convection eastward along
the I-64 corridor this afternoon, eventually reaching our NW CWA by
23z or so. Additional development is expected to the southwest of
the current convection, which CAMs suggest could grow upscale and
into a line of strong to severe storms with bowing segments pushing
into our KY counties west of I-65. Additionally, we are beginning to
see convection pop along our south-central KY counties, which is
about an hour ahead of the latest HRRR run. Skycover has cleared out
more than originally anticipated, allowing our region to
destabilize to around 2500 J/kg of SBCAPE with steep low level
lapse rates around 8C/km. Expect to see these scattered storms
continue through the afternoon and push eastward.
CAMs and model soundings continue to suggest the more supportive
environment for this evening`s round of storms is to our west, where
instability looks to be around 2000+ J/kg of MUCAPE. Most hi-res
guidance is consistent on MUCAPE between 1000-2000 J/kg across our
western half (west of I-65) of the CWA. Additionally, forecast
sounding suggest mostly a unidirectional wind profile. RAP forecast
soundings and HREF ensemble agree on seeing 850-700mb winds increase
from roughly 15 kts this afternoon to 35kts by this evening. As a
result, we should see effective shear increase to 20-35kts. Better
shear will help keep storms more organized, but by 02-03z we should
see the convective line start to weaken as instability should
dissipate.
With CAMs consistently suggesting bowing segments, primary hazards
with storms this evening and tonight will be damaging straight line
winds, frequent lightning, and possibly some hail. Low level
moisture transport should be enhanced as low-mid level winds
increase, which will likely result in seeing PWATs rise above 2
inches. With high moisture content available, torrential rain rates
may lead to some flooding issues. Storm motions appear to be
progressive, but any training storms or common flooding hot spots
may see some water issues later on this evening. After discussing
with neighboring WFOs, no expansion to the Flash Flood Watch is
planned at this time.
Should see an end to convective activity sometime between 04-06z
tonight as instability is lost. We should have some lingering
showers through the overnight before renewed convection pops.
However, CAMs suggest we`ll see more of a scattering of showers and
storms. Temps for tomorrow will reach the low to mid 80s.
.Long Term...(Sunday night through Saturday)
Issued at 234 PM EDT Sat Jul 10 2021
A nearly stationary upper level low over the Midwest will begin to
slowly drift northward starting Monday as it gets picked up by a
passing trough. Flow out ahead of this upper level low will
generally be out southwest and continue to pump Gulf of Mexico
moisture into our region, resulting in an atmosphere with high PWATs
and muggy conditions at the surface. This steady supply of moisture
feeding into our area combined with weak capping should allow for
periodic shower and storm chances to continue through early next
week. Heavy rain in thunderstorms is a good bet, and areas that see
repeated storms over short periods could experience localized flash
flooding. Highs during this timeframe will likely only top out in
the low to mid 80s given the expansive clouds and moisture in the
region.
For the mid to late week timeframe, a cold front will move out of
the Great Plains and Great Lakes region toward the Ohio Valley, but
possibly stall just north of our region by Thursday/Friday. Rain and
storm chances will be highest near the proximity of the front, with
them dropping off considerably to the south. At this time, southern
IN would likely have the best chance to see showers/storms while
southern KY may stay mostly dry save for isolated/scattered diurnal
convection that fires off. High temperatures will generally be in
the upper 80s to low 90s ahead of the front.
&&
.Aviation...(00Z TAF Issuance)
Issued at 652 PM EDT Sat Jul 10 2021
IMPACTS: Showers and thunderstorms are expected at the terminals
this evening and into the overnight hours. Some of the storms could
be strong with MVFR/IFR conditions and gusty winds.
DISCUSSION: NW-SE oriented line of convection currently stretches
from near Jasper, IN southeast to just south of Lexington, KY. This
activity will impact KSDF/KLEX/KHNB very early in the TAF period.
Once this line moves off to the northeast, a relative lull in
convection looks likely for a few hours with just a few scattered
storms moving across the region. Will be watching an area of
stronger storms out near Mount Vernon, IL that will push into the
region after 11/02Z. These storms will likely affect KHNB/KSDF and
KLEX. Convection may remain a bit north of KBWG early this evening,
but current thinking is that KBWG could get in on some storms later
tonight, though confidence down that way is lower than average at
this time. Convection is expected to diminish overnight due to loss
of heating and stabilization of the PBL. Much of the guidance
suggests the development of low clouds overnight with ceiling
possibly dropping into the IFR range. Winds look to remain elevated
overnight which may be enough to preclude fog formation.
CONFIDENCE: Med-High on elements at KHNB/KSDF/KLEX. Low-Med at KBWG.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...Flash Flood Watch until 8 AM EDT /7 AM CDT/ Sunday for
KYZ023>028-053-061>064-070>074-076.
&&
$$
Mesoscale...MJ/RAS
Short Term...CJP
Long Term....DM
Aviation.....MJ
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
921 PM CDT Sat Jul 10 2021
.UPDATE...
921 PM CDT
The going forecast theme of wet and cool into tomorrow continues.
Confidence has increased a smidge that if there is a heavier rain
axis (isolated 2+ inches) overnight into Sunday morning, it would
be further south than indicated by earlier guidance, more so
along to a little south of I-80 corridor. But whether or not that
sets up remains uncertain. Also the lightning potential looks even
lower for the rest of the night.
Due to several MCSs in the southern Corn Belt the past 24-36
hours, there remains a multitude of surface lows/circulations
around 1010 millibars across central/southern Illinois into
Missouri. A gradual consolidation will occur through Sunday
morning as the upper low digs southward into Missouri. With this
slight intensification/organization of the system, as well as
improved upper jet support by late tonight into Sunday morning, a
more synoptically forced west-to-east moderate/heavy rain zone is
likely to develop north-northeast of the surface low over northern
Illinois and northwest Indiana. On the mesoscale, a remnant but
gradually fading MCV near Lincoln, IL may also help focus the
heavier rain area in a zone in the southern forecast area. The 00Z
ILX sounding sampled 1.79 inches of PWAT and 700 mb Tds of 6C
with this, really highlighting warm rain processes.
Despite the ingredients and some signal being there in guidance
(for instance the 00Z RAP had 2+ inches in LaSalle to Kankakee
Counties), there remains a fair amount of uncertainty on if this
can come together. Also, and thankfully, the impact if a localized
corridor of 2+ inches will probably be limited if not in the
metro in part to antecedent conditions being not too moist, as
well as occurring overnight into early morning on a Sunday.
Nonetheless, something we will keep a tactical eye on.
Finally, the thunder threat looks quite limited. There was no
lightning observed by the lightning networks and satellite in the
CWA this afternoon or early evening, and satellite and cell cores
continue to support that trend. So have suppressed the forecast
thunderstorm chances in the far south for much of tonight.
MTF
&&
.SHORT TERM...
255 PM CDT
Through Sunday night...
The cut off upper low and associated surface low continues to move
east-southeast north of I-74, creating showers in my forecast area,
and thunderstorms in west central IL, where greater instability
(higher CAPE values, moisture atmosphere south of the warm front)
exists. The low is expected to take a more easterly path, but
movement will be slow as it meanders around central to north IL.
With no clear forcing movement, the exact path of the low is
difficult to determine, with low confidence on precipitation
location. Chances for rain showers, some of which can have heavy
rainfall, will continue throughout the afternoon and into the
evening, with heavy precipitation initially south of I-88, but
eventually working into the Chicago suburbs and the City of Chicago.
Some showers may reduce visibilities to as low as 2.5 miles.
Conditions for increased thunderstorm chances in our southern
forecast area (south of I-80) will occur overnight, with greatest
chance still expected near to a few hours after midnight tonight.
The chance for heaviest showers is also expected overnight, with
some isolated possibilities of 2+ inches, but nailing down where
this will occur is difficult at this time.
Winds will remain easterly throughout the short term forecast
period, with afternoon gusts up to 15 mph possible. Easterly winds
will die down a bit in the late afternoon/early evening, but are
expected to increase again overnight, with 20 to 25 mph gusts
possible after midnight and into Sunday morning. Even stronger gusts
will occur over Lake Michigan, creating a high swim risk and
issuance of a small craft advisory.
Showers continue Sunday, with areas concentrated further east, but
still including Chicago and it`s suburbs, while the thunderstorm
threat remains south, later shifting towards northwest IN. Chances
for showers and thunderstorms continue into Sunday evening, although
the chances will decrease throughout Sunday evening.
As is the case with cut-off upper lows and weak steering flow, the
surface low will continue to spin in the vicinity of south
Wisconsin/north Illinois/northwest Indiana Monday morning,
maintaining the chance for showers and occasional thunderstorms
throughout Monday.
BKL
&&
.LONG TERM...
Monday through Saturday...
245 PM...Primary forecast concern is precip chances/timing.
The models have trended a bit further east with the upper low
Monday into Monday night and this will allow for scattered showers
and few thunderstorms mainly Monday afternoon into Monday evening.
Difficult to pin down the best location for precipitation and for
now, likely pops in the afternoon seem on track. There should be
a steady decrease in the activity Monday night, which could end up
becoming dry for much of the area. The upper low quickly departs
to the north on Tuesday though there remains a chance for showers
and perhaps a thunderstorm Tuesday afternoon. Low confidence for
coverage, which could end up being isolated with Tuesday night
into Wednesday morning now looking fairly dry.
There appears to be better agreement for the midweek time period
but still low confidence for how trends emerge. An upper trough
will dig into the Dakotas Tuesday night into Wednesday morning
with convection expected to develop in this region and then
possibly move generally easterly to the western Great Lakes into
Wednesday night, possibly staying north of the cwa. An associated
cold front will then move south across the area Wednesday night
or Thursday with new convection developing along/ahead of it.
Timing/location of these features still uncertain from this
distance but precipitation chances increasing Wednesday into
Wednesday night, possibly peaking on Thursday, all seem on track
for now. Trends then support precip chances possibly being
confined to the southern cwa or even south and southwest of the
area by next Friday/Saturday as high pressure builds across the
upper midwest and Great Lakes region.
Temperatures look to stay generally in the 70s on Monday but
rebound into the lower 80s Tuesday with expected lower precip
coverage and possibly some breaks of sunshine. Wednesday still has
the potential to be rather warm, with highs in the mid/upper 80s
but this will be dependent on precip timing. cms
&&
.AVIATION...
For the 00Z TAFs...
Primary aviation forecast concerns...
* Timing of lower cigs (IFR likely)
* Timing of heaviest showers and associated lower vis/cigs
* Gusty east northeasterly winds to 20-25 kt
* Low potential for thunder overnight
Light rain continues across the region early this evening with
MVFR cigs beginning to lift into the Chicago area terminals.
Expect ceilings to trend downward through the evening hours as
more steady rain expands in coverage. There may be brief breaks in
the rain at times, but overall expecting at least light rain the
persist overnight through the morning hours tomorrow, potentially
even lingering into the afternoon hours, especially out toward
RFD. Guidance continues to suggest that IFR cigs may continue
well into the afternoon and evening hours tomorrow. For now have
opted to lift cigs back to low-end MVFR as the coverage of showers
decreases.
East northeast winds will increase through evening and overnight
hours, with gusts to 20 to 25 kt possible for much of the day on
Sunday. There remains a low potential for embedded thunderstorms
overnight. Did consider a PROB30 mention for GYY, but based on
current observational trends, confidence is too low for a formal
TAF mention.
Petr
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement...ILZ006-ILZ103-ILZ104...1 AM Sunday to
4 AM Monday.
IN...None.
LM...Small Craft Advisory...LMZ740-LMZ741-LMZ742...4 AM Sunday to 1
AM Monday.
Small Craft Advisory...LMZ743-LMZ744-LMZ745...4 AM Sunday to 7
PM Sunday.
&&
$$
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Area Forecast Discussion
National Weather Service Newport/Morehead City NC
952 PM EDT Sat Jul 10 2021
.SYNOPSIS...
Offshore high pressure will build over the region this weekend
and continue through next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 955 PM Sat...Apart from a rogue shower over northwestern
Washington County, CWA is now devoid of convective activity.
Forecast in solid shape with no further changes planned.
Main changes from the afternoon package was to lower coastal
PoPs slightly for the overnight period, bringing more
conservative guidance into the forecast as coastal activity
usually struggles to get onshore. Broken low stratus possible
west of Highway 17 early Sunday morning, but fog risk looks
increasingly minimal with thick cirrus deck overhead.
Prev disc...High pressure offshore dominates the forecast as
the weak frontal boundary inland has washed out over the area
and the seabreeze continues to push inland, clearing skies
behind it. Have slightly lowered PoPs but have left low end schc
along and ahead of the seabreeze where short lived showers may
blossom the rest of the afternoon. Any convection that does get
its act together quickly falls off with loss of heating after
sunset.
Overnight, mainly dry conditions forecast with the ridge in
place except for along the lower OBX and Crystal Coast where
offshore showers may meander ashore. Muggy morning in store
with Lows in the low 70s inland and mid 70s for coastal areas.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
As of 345 PM Saturday...The Offshore mid/upper level ridge
continues to build over the area with 500mb heights reaching
into the upper 590s just offshore. A weak shortwave
trough lifts across the area providing slightly more support for
afternoon convection, making scattered showers and thunderstorms
possible. Highs a degree or two cooler than Saturday with
increased cloud coverage cooling things slightly despite the
persistent Serly flow, upper 80s for most inland areas, touching
90 in particular hot spots, and mid to upper 80s for coastal
areas.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
As of 230 AM Saturday...A typical summertime pattern will
persist through the long term with the Bermuda high centered
offshore bringing southwest flow across the area and seasonably
hot and muggy conditions. Highs will be in the lower 90s inland
and mid to upper 80s along the coast and lows in the low to mid
70 each day.
Upper ridging over the Atlantic builds westward early to mid
portion of next week with subsidence aloft suppressing most
convection but cannot rule out isolated to widely scattered
showers during the afternoon. The ridge begins to break down for
the latter half of the week with somewhat better chances for
showers/storms each afternoon. With limited shear present,
thunderstorms are expected to remain sub- severe.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /Through 00Z Monday/...
As of 740 PM Sat...VFR conditions prevail across the terminals
this evening with a line of decaying convection from DPL to OCW.
Any convective activity should safely come to an end by 01Z
with mainly VFR conditions expected until around 09-10z. Trusted
guidance indicates a scattered to broken area of low stratus
developing along a rough axis from PGV to DPL by this time,
likely courtesy of this afternoon`s spotty rainfall. Fog looks
increasingly unlikely with persistent and thick cirrus deck
overhead.
VFR conditions return to all terminals shortly after sunrise,
with development of cu deck and slightly more coverage of
showers and thunderstorms in the afternoon. NAM and HRRR
soundings point to a brief period of MVFR cigs mid-morning as cu
deck first develops, before lifting to VFR levels by 18z.
Confidence in this was too low to show explicitly in TAFs.
LONG TERM /Sunday through Wednesday/...
As of 245 AM Friday...Pred VFR expected through the long term
with high pressure centered offshore bringing warm and muggy
conditions. Isolated to widely scattered showers and storms will
bring brief periods of sub-VFR conditions generally during the
afternoon/early evening hours. Best chance for storms will be
Sunday with lesser chances early to mid next week. Also cannot
rule out patchy late night/early morning shallow fog.
&&
.MARINE...
SHORT TERM /Today and tonight/...
As of 4 PM Saturday...No adjustments needed this update.
As of 140 AM Saturday...High pressure building across regional
waters keeps conditions relatively benign. Latest obs show 2 to
4 ft seas with 7 to 8 sec periods. Southern waters experiencing
the stronger SW winds 10 to 15 kts with occasional gusts up to
20kts while northern waters show variable winds 5 to 7kts. Gusts
die down overnight and seas remain 2 to 4 ft.
LONG TERM /Sunday Through Wednesday/...
As of 245 AM Friday...Bermuda high pressure persist offshore
bringing southwest winds through the long term. Gradients will
be slightly tightened Sunday and Sunday night with winds around
15-20 kt expected with around 15 kt or less the rest of the long
term. Seas will generally be 2-4 ft but could see up to 5 ft
across the outer portions of the coastal waters Sunday/Sunday
night in response to stronger winds.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...MHX
NEAR TERM...MS/CEB
SHORT TERM...CEB
LONG TERM...SK
AVIATION...SK/MS
MARINE...SK/CEB
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1019 PM CDT Sat Jul 10 2021
.UPDATE...
Issued at 1019 PM CDT Sat Jul 10 2021
Updated for aviation discussion below.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 310 PM CDT Sat Jul 10 2021
An upper low over the mid Missouri Valley will close off as it
continues southeastward tonight. Showers associated with the upper
low are lingering across southern MN this afternoon, but as the low
continues to pull away these showers should diminish into the early
evening hours. The upper low will remain nearly stationary over the
mid Mississippi Valley into early next week, but it should be just
far enough away to keep any substantial cloud cover and/or shower
potential to our southeast. Today`s diurnal CU and stratocu will
dissipate this evening from north to south as drier air across
central MN and WI works southward behind the low.
Smoke from the wildfires in Ontario and Manitoba is evident on
satellite across northern MN, Lake Superior, and most of southern
Ontario. Prevailing northeast flow through Sunday evening should
bring some of this elevated smoke southwest across the area. The
HRRR smoke model indicates an arrival overnight and lingering into
early next week, resulting in filtered sunshine.
.LONG TERM...(Monday through Saturday)
Issued at 310 PM CDT Sat Jul 10 2021
The cutoff low over the mid-Mississippi valley departs eastwards on
Monday, with a chance for a few lingering rain showers during the
day across portions western Wisconsin. This weekend`s persistent
easterly flow becomes more southerly as the low departs, which will
allow for temperatures to warm Monday and Tuesday. Highs in the low
to mid 80s look possible Monday and temperatures should warm by a few
degrees into the mid to upper 80s Tuesday. Dew point values will
also rise into the mid 60s Tuesday, leading to more muggy conditions
ahead of the next approaching system midweek.
Guidance has come into better agreement over the last 24 hours with
the shortwave forecast to track along the northern tier of the CONUS
midweek, with Wednesday looking like the best chance for
precipitation across the region. A few models depict a weak lobe of
vorticity generating a band of showers and perhaps a few
thunderstorms Tuesday afternoon, but more widespread precipitation
will develop with the shortwave over the Dakotas late Tuesday/early
Wednesday, and spread the southern half of MN/WI during the day on
Wednesday. The shortwave remains fairly progressive with
precipitation likely exiting the area by Thursday morning, which
along with fairly seasonable PW values should limit the chance for
excessive rainfall or flooding. Most solutions show the potential for
widespread rainfall amounts of around an inch so this system has the
makings of a beneficial rain for most of the area. Deterministic
models do show shear and instability values sufficient for severe
thunderstorms developing to the south of this system, but the current
track would likely keep this threat farther south into Iowa.
The rest of the week appears dry as ridging redevelops over the
central CONUS. Temperatures will likely return to above normal values
by the weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1019 PM CDT Sat Jul 10 2021
High level smoke is evident on satellite as far south as central MN,
and it will continue to move southward tonight and Sunday. Whether
it will pose a surface visibility restriction is not certain yet. So
far it seems there are not any reduced visibilities in northern MN,
eastern ND, or adjacent portions of northwest Ontario, but this will
need to be watched as there are some lower visibilities farther north
in Ontario.
KMSP...No other concerns.
/OUTLOOK FOR KMSP/
Mon...VFR. Wind NE 5-10 kts.
Tue...VFR. Slight chance p.m. MVFR/SHRA. Wind W 5-10 kts.
Wed...Chance MVFR/SHRA/TSRA. Wind S 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
UPDATE...TDK
SHORT TERM...Borghoff
LONG TERM...ETA
AVIATION...TDK
Area Forecast Discussion
National Weather Service Nashville TN
951 PM CDT Sat Jul 10 2021
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Made only a few minor changes to some of the hourly POP and temp
grids for this forecast cycle as the current forecast is on
track. Just isolated showers and brief storms so far this evening
in Middle TN as all the heavy/training rains remain north of our
CWA...in southern KY. Suspect things will remain pretty quiet for
us for the next couple hours. Past several HRRR runs as well as
some of the other CAMs continue to slightly delay the arrival of
storms moving toward us from the northwest. Greatest chance of
storms appears to be 07Z to 12Z over the northwest half of Mid
TN...with decaying storms mainly over the southeast areas from
about 12Z to 16Z.
&&
.AVIATION...
00Z TAF DISCUSSION.
CKV/BNA/MQY/CSV...Per moist and unstable airmass conditions in
place, very hard to delineate a time period in which tstms could
not occur. However, also very hard to determine tstms development/
movement across terminals. Mentioning of VCTS most appropriate
here. Sfc pressure gradient influences will continue to be strong
enough to support gusts approaching 25kts with swly sfc winds.
In some instances MVFR vsby and ceilings will be possible during
tstm events. Prevailing VFR vsbys with rain showers possible
11/12Z-11/24Z.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......Vannozzi
AVIATION........JB Wright
Area Forecast Discussion
National Weather Service Norman OK
652 PM CDT Sat Jul 10 2021
...New AVIATION, UPPER AIR...
.SHORT TERM...
(This evening through Sunday)
Issued at 322 PM CDT Sat Jul 10 2021
Storms are expected to continue to develop across southwest
Missouri, southern Kansas, northeast Oklahoma and eventually
north-central Oklahoma this afternoon.
Storms will continue to develop along and ahead of a cold front that
is moving into northwest Oklahoma this afternoon. Modest instability
and strengthening deep layer sheer will support, storms with
supercellular characteristics, at least initially. These storms will
pose a large hail, damaging wind and at least a very low tornado
risk. However, veered low level flow and more linear forcing along
the surface front will lead to an expected quick transition to a
more linear mode along the boundary. Primary hazard will become
damaging wind gusts and with a secondary heavy rainfall concern as
precipitable water values remain high. However, progressive nature
of this activity is expected to limit the overall heavy rainfall
threat.
HRRR would suggest convection would approach the I-40 corridor 9pm
or a little after. There has been a trend of slowing the southward
progression down in the laster few runs. The storms would then
approach the Red river around 3 or 4 in the morning. Although an
overall downward trend is expected after midnight, some severe risk
does appear possible through the night time hours.
Will keep some lingering precip chances along the Red river Sunday
morning, but most of the activity should be south of the area.
Models are also showing another embedded shortwave rotating around
the upper low to our northeast during the day Sunday. This may
result in a few showers or thunderstorms during the afternoon hours,
mainly along and east of the I-35 corridor. Otherwise, daytime temps
will be a bit lower on Sunday as will the dewpoints as slightly
drier air filters south behind the front.
&&
.LONG TERM...
(Sunday night through next Friday)
Issued at 324 PM CDT Sat Jul 10 2021
The front exits the area and winds become light Sunday night and
winds veer to the SE/S by Monday afternoon as the surface ridge
axis moves eastward. The NAM/GFS suggest thunderstorm development
over western north TX and western OK Monday evening into early
Tuesday morning as a LLJ develops atop the retreating cold front,
or weak warm front. Left POPs low for now, but will continue to
watch trends.
The midlevel low pressure system that brought us the cold front
moves slowly across the midwest, before lifting northeast across
the Great Lakes on Tuesday. Meanwhile, the broad upper ridge that
has contributed to record heat across the western CONUS begins to
break down and north flow aloft will likewise weaken over our area.
A wave then translates across the northern plains midweek, and
there are low POPs for precipitation for northern Oklahoma on
Wednesday night into Thursday and again Thursday night into Friday.
The associated frontal boundaries and bulk of precipitation,
however, appears to remain well to our north.
Thompson
&&
.AVIATION...
(00Z TAFS)
Issued at 640 PM CDT Sat Jul 10 2021
Showers and thunderstorms are expected to increase along a cold
front currently moving across northern Oklahoma. Although
expecting ceilings with the CBs to lower just above MVFR,
reduced visibilities during heavy rain may produce brief periods
of MVFR to IFR conditions. Otherwise away from the CBs, conditions
should stay VFR. Winds behind the cold front will shift and
become northerly. However, outflow boundaries produced from storms
may result in more variable directional surface winds.
&&
.UPPER AIR...
Issued at 640 PM CDT Sat Jul 10 2021
No upper air flights are planned at this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 68 85 64 87 / 80 0 0 10
Hobart OK 68 90 65 90 / 50 0 10 10
Wichita Falls TX 73 93 68 92 / 70 10 10 10
Gage OK 65 88 63 91 / 0 0 0 0
Ponca City OK 66 82 62 86 / 50 20 10 0
Durant OK 72 92 67 91 / 90 30 10 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...30
LONG TERM....01
AVIATION...68
Area Forecast Discussion
National Weather Service Paducah KY
657 PM CDT Sat Jul 10 2021
.UPDATE...
Issued at 657 PM CDT Sat Jul 10 2021
Will be clearing out much, if not all, of southern Illinois from the
Severe Thunderstorm Watch shortly. Will need to leave southeast
Missouri going for another hour or two.
The AVIATION section has been updated for the 00Z TAF issuance.
&&
.SHORT TERM...(Tonight through Monday night)
Issued at 329 PM CDT Sat Jul 10 2021
SPC mesoanalysis indicates that over 2000J/kg of mixed-layer CAPE has
developed across the region. However, the shear across the region
remains weak despite the mid-level low to the northwest of the
area and the presence of at least one MCV. The primary surface
boundary has lifted north of the region leaving southwesterly
low-level flow over our entire region.
Look for continued scattered thunderstorms through the late
afternoon and evening, but how organized they will be is in doubt
at this time. The latest HRRR output validates the lack of shear
indicated in the mesoanalysis by not showing the bowing segments
that earlier runs showed. It appears that the damaging wind
threat is decreasing. However, low-level lapse rates are rather
steep and DCAPE is approaching 1000 J/kg. Both parameters are
maximized over west Kentucky. If the storms are able to grow
upscale, we could still see some damaging winds, especially across
southeast Missouri and southern Illinois.
Most, if not all, of the convection should be southeast of our
region by 06Z, but the HRRR does develop some scattered convection
overnight across the area so will keep chance PoPs just in case
the HRRR has that right.
As the mid/upper-level low descends on the region Sunday, any
semblance of shear will be limited to west Kentucky and the HREF
indicates that it will be weak even there. Also, low clouds will
likely hold down heating and instability well below today`s
levels. The cold front is forecast to reach far northwest portions
of the region in the afternoon and then stall out into Monday. The
front could focus convective development in southeast Missouri
and southern Illinois in the afternoon. Really see no reason why
convection would be very organized, but should see decent
coverage. It will try to push east across the region through the
evening.
For Monday while the mid/upper-level trough will not make much
eastward progress, much of its energy will be drawn northeast as a
trough moves east across southern Canada. Any reasonable shear and
instability will likely44 be focused to our east, so we will
focus our PoPs on Monday in Kentucky and Indiana, however, the
NBM-based PoPs are likely too high given the situation.
As for the Flash Flood Watch, we plan to leave it alone for now.
The heavy rainfall will be done by 06Z, but will allow later
shifts to cancel early, if needed. We briefly considered
expanding it southward with some concern for training along the
southern border of the region this evening. However, the latest
HRRR is not as bullish on training down there. In general,
convective elements should be moving fast enough to prevent
widespread significant flooding, but the brief intense rates may
briefly overwhelm drainages, causing more of a nuisance flooding
situation.
.LONG TERM...(Tuesday through Saturday)
Issued at 329 PM CDT Sat Jul 10 2021
The upper air pattern starts out on Tuesday with a 500h trough over
Missouri, along our western edge. By Wednesday this trough weakens
considerably and our flow is weak, but almost zonal with weak
ridging along both coasts. On Thursday, the clusters have a weak
trough over the upper midwest, in the area of Minnesota. This trough
sharpens up a bit on Friday generally along a Wisconsin to eastern
Oklahoma line. There is some variability in placement among the
clusters, but nothing too significant. By Saturday there is more
variability in location and time of the trough ranging from a
moderate strength over the Great Lakes down to PAH to more of an
open wave somewhere over the Great Lakes.
The main precipitation pattern during this period has most of the
precipitation from MS into central KY on Tuesday. Wednesday looks to
be the driest day as the next system forms over the northern Plains.
This spreads into the upper midwest on Thursday and settles over the
Ohio Valley Friday into Saturday as the surface cold front becomes
more east-west over either central Illinois/Indian or maybe a bit
farther south closer to the Ohio River.
Seasonal temperatures expected with upper 80s to around 90 for
highs. Dew points are forecast to be in the upper 60s to lower 70s
throughout the period.
&&
.AVIATION...
Issued at 657 PM CDT Sat Jul 10 2021
The convection is reasonably on schedule. KMVN is already in the
clear and the other TAF sites should be done by 03Z. Some gusty
winds up to 35kts will be possible along with IFR conditions. IFR
or lower MVFR ceilings are still expected to develop over all
sites overnight and linger through much of Sunday. Scattered
convection will be possible throughout the area Sunday afternoon,
but will leave it out at this time.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Flash Flood Watch through Sunday morning for ILZ075>078-080>094.
MO...Flash Flood Watch through Sunday morning for MOZ076-086-087.
IN...Flash Flood Watch through Sunday morning for INZ081-082-085>088.
KY...Flash Flood Watch through Sunday morning for KYZ004-005-007-010-
011-013>016-018>021.
&&
$$
UPDATE...DRS
SHORT TERM...DRS
LONG TERM...PS
AVIATION...DRS
Area Forecast Discussion
National Weather Service Pocatello ID
128 PM MDT Sat Jul 10 2021
.SHORT TERM...Tonight through Monday night. WV imagery shows a
strong area of high pressure centered over Las Vegas with broad
ridging extending into Idaho. A trough is seen around 135W off the
WA coast moving east. Models indicate the trough will make landfall
early Sunday morning, though it pushes through with very little
moisture. By mid to late Sunday morning, the trough should be in the
Panhandle area of Idaho. High-res models are indicating some
isolated thunder in the Island Park area tomorrow afternoon, but
storms may stay just north of the border. The trough will bring
winds to the Snake Plain, though winds should be just shy of Lake
Wind threshold for American Falls Reservoir. Monday looks to be dry
as well, though another trough will be making its way to the PAC NW
late in the day
Vis and natural color imagery show smoke dispersing over the region
from wildfires in CA, OR, and WA, as well as some fires in our
Central Mountains. Therefore, it seems prudent to include smoke in
our forecast as well. Hinsberger
.LONG TERM...Tuesday through next Saturday. The mean upper ridge
remains positioned over the Great Basin throughout the period as
weak to modest Pacific disturbances translate east along the
Canadian highline Tuesday and Thursday. By Saturday, a low pressure
center appears to set up along or off the NW coast with the ridge
axis shifting over the Wyoming Rockies and expanding northward into
Montana. Each passing trough should bring some wind and slightly
cooler temperatures to the region and perhaps even a shallow monsoon
push into the Utah/Montna border regions with resulting isolated
convection, otherwise unseasonably hot and dry conditions should
persist across the region. Huston
&&
.AVIATION...Ridging will continue through today and shift eastward
tonight while a trough pushes through the Panhandle area tomorrow
morning. VFR conditions will likely continue, but wildfire smoke may
briefly drop visibility MVFR. Current area of smoke concern is the
KSUN terminal, though as ridging shifts to the east, HRRR Smoke is
advancing the increased concentrations to KIDA and KDIJ by sunrise
tomorrow morning. Winds will generally be light, but an occasional
gust to 20kts in the Snake Plain this afternoon is possible. Winds
increase tomorrow, but should be after the current TAF period.
Hinsberger
&&
.FIRE WEATHER...Initial focus will be on wind and RH components
tomorrow as an upper disturbance passes to our north. At the
surface, a dry cold front will push through tomorrow afternoon,
enhancing wind speeds across the area. This will nudge us close to
critical fire conditions in the afternoon and early evening. Have
added a Fire Weather Watch for zones 410, 425, 475, and 476 tomorrow
afternoon/evening. There may be some isolated thunder in the Island
Park area in the afternoon, but most models indicate the best
chances will be on the Montana side of the border. The forecast
remains dry, even with another trough pushing in from the west on
Tuesday. The trough will certainly cause another round of strong
winds across the region, and humidity may be low enough to take us
to critical fire weather conditions. Models are bringing in a little
more moisture to the area late in the week, so we may see some
thunderstorms work their way in the forecast by Thursday and Friday.
Hinsberger
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 9 PM MDT Monday for IDZ051-055>057.
Fire Weather Watch from Sunday afternoon through Sunday evening for
IDZ410-425-475-476.
Heat Advisory from noon Sunday to 9 PM MDT Monday for IDZ052>054-058-
059-075.
&&
$$
Area Forecast Discussion
National Weather Service Reno NV
302 PM PDT Sat Jul 10 2021
.SYNOPSIS...
Dangerous heat is expected this weekend into next week. Best advice
is to hydrate and limit outdoor activity during the afternoon hours.
A few afternoon and evening thunderstorms are expected for next few
days, mainly south of Highway 50. Smoke from the Beckwourth Complex
fire will affect portions of extreme eastern California and western
Nevada with periods of degraded air quality and reduced visibility.
&&
.DISCUSSION...
Main forecast change to extend Excessive Heat Warning until Tuesday
evening.
The very strong ridge of high pressure (near 600 DM currently) will
persist overhead into early next week before finally weakening as
a trough of low pressure approaches the West Coast mid to late week.
Afternoon and evening breezes trend up Sunday to Monday and continue
next week as the trough impinges on the West Coast. The winds may
not be of major concern to many with gusts between 20-35 mph (not
particularly unusual for summer zephyr); however, with parched
fuels they will bring elevated fire weather concern.
HEAT
* Forecast not adjusted too much with memorable heat wave
continuing through Tuesday before some gradual cooling to near
or a bit above average (more usual summer heat) mid to late next
week. With only minor cooling Tuesday and a mild start to that
day, the Excessive Heat Warning was extended for one more day.
As far as details, the main adjustment was to tinker with the
latest high temperature guidance for Sunday with the result a
downward adjustment of 1-3 degrees for many spots. Model 700 mb
temperatures remain 18-19C Sunday in the NAM, GFS, and ECMWF for
western NV. Per a local rule of thumb that works well in mixed
summer conditions (panned out well yesterday), these 700 mb
temperatures correspond to highs of 104-106F. This rule plus
support from the latest guidance from the NBM gives higher
confidence that highs may fall just a tad short of all-time
records for the Reno airport (108). In any case, a couple
degrees does not change the fact that it will be exceedingly
hot!
THUNDERSTORMS
* Earlier today, chances were increased a bit up into the Reno-
Sparks area (mainly north and east of Reno) with persistent
hints from the HRRR that isolated cells would form there. In
fact, one lone cell (weak) already worked from near Cold Springs
up towards Pyramid Lake. This afternoon and early evening
westerly winds are expected to develop in the Sierra Front for
added convergence for storms. Still, the highest concentration
of cells is expected to remain south of Highway 50 across Mono,
Mineral, and southern Lyon counties.
Sunday and Monday, deep moist convection (thunderstorms!) is
expected to be restricted to south of Highway 50 in Mono,
Mineral, and southern Lyon counties. Farther north, increased
southwest flow aloft is simulated Sunday which is likely to
bring some atmospheric stabilization along with less focus for
storms as an earlier push of westerly winds limits the time
convection can build before surface convergence is lost.
As far as thunderstorm character, relatively decent moisture
(PWATS around 0.80" or so)/moderate dewpoints and the extreme
heat will provide weak to moderate instability (perhaps up to
500-800 J/KG), up to the Reno-Sparks area today shrinking
southward Sunday-Monday as drier air moves into areas north of
Hwy 50. Strong outflow in excess of 45 mph (due to a very deep
mixed layer, inverted V soundings) and lightning will be the
primary threats from storms.
FIRE/AIR QUALITY CONCERNS
* See fire weather discussion below for more details regarding
wind (periods of enhanced breezes). As for air quality, the
Reno-Sparks area received a "nice" dose of smoke particulates
from the Beckwourth Complex this morning, with air quality
degrading to unhealthy for sensitive groups. It has since begun
to disperse as mixing increases this afternoon. Another round is
certainly possible tonight into early Sunday although an earlier
west wind may cut down the degraded air quality timing a bit.
For the latest air quality, go to `fire.airnow.gov`
&&
.AVIATION...
Very hot temperatures continue this weekend and into next week with
density altitude concerns, particularly for smaller aircraft.
The Beckwourth Complex in Plumas County continues to burn actively.
Mixing during the daytime hours will bring improved visibility outside
of the areas immediately around the fire; however, slantwise
visibility may remain slightly restricted. General haze is
possible elsewhere due to other wildfires burning in the West.
Wind-wise for Sunday, and likely for much of the week, we`ll see winds
return to more "usual" or slightly elevated levels with afternoon
gusts 20-30 kts.
As for thunderstorms, expect isolated to scattered thunderstorms
this afternoon/evening, primarily south of Highway 50; however,
isolated cells are possible up to Pyramid Lake across far western
NV. Storms have the potential to bring localized heavier rain
with lowering CIGS/VIS and higher terrain obscuration; however, the
greatest concern will be gusty and erratic outflow winds to 40+
kts and lightning. Outflows may travel well away from the parent
thunderstorm and kick up dust across the west central Nevada Basin
and Range. Sunday and Monday, storms are expected to be restricted
well south and east of KRNO/KCXP/KMEV as drier flow pushes into
western NV and northeast CA. -Snyder
&&
.FIRE WEATHER...
* Hot-unstable conditions favorable for large plume growth on
ongoing fires.
* Afternoon and evening thunderstorms possible today for the Eastern
Sierra and Sierra Front into central Nevada.
* Breezy afternoons with periods of critical fire weather conditions
Sunday through Monday.
Dry and unstable - Relatively dry and unstable mid and upper levels
will continue to allow for strong plume development of ongoing fires.
Thunderstorms - Another round of fairly widespread thunderstorms is
expected again today. Moisture has increased (PWAT 0.6-0.8") in areas
that have seen storms the last few days so would expect most storms
to be on the wet side. Still, there could be a few drier storms on
the periphery. Storm coverage is forecast to shrink Sunday through
Tuesday, mainly confined to the eastern Sierra and portions of
Mineral County.
Breezy afternoon Winds (Sun-Tue) - A slightly enhanced zephyr wind
is expected from Sunday through at least Tuesday. This will create
periods of critical fire weather conditions, especially along the
Sierra Front and portions of NW Nevada. No day really stands out as
a big step above the others, and for the most part, this is a fairly
typical afternoon wind during the summer, so at this point no fire
weather products are anticipated. That being said, expect periods
of critical fire weather conditions each afternoon in typically
breezy spots along the Sierra Front.
-Zach
&&
.REV Watches/Warnings/Advisories...
NV...Excessive Heat Warning until 9 PM PDT Tuesday NVZ001-003>005.
CA...Excessive Heat Warning until 9 PM PDT Tuesday CAZ070-071.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Blacksburg VA
957 PM EDT Sat Jul 10 2021
.SYNOPSIS...
A warm front will track north tonight ahead of low pressure
moving through the Ohio Valley. This will bring another round of
showers and thunderstorms to the region Sunday. Monday through
Thursday high pressure will cover the Mid Atlantic region and
the Carolinas, however the daily threat of showers and
thunderstorms will continue well into next week.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
As 957 PM EDT Saturday...
... Showers and storms will slowly diminish after midnight as a
warm front gradually lifts north across the region....
Our weather pattern for the remainder of the weekend will be reliant
upon a warm front/quasi-stationary boundary lifting in from the
Tennessee River Valley/Virginia State Line and a deepening trough
over the central Plains region. On top of this, we will have a
strengthening area of high pressure off the Atlantic coast which
will nudge our frontal boundary further north while fending off our
trough to the west keeping activity isolated to scattered heading
into early next week.
Currently as of 955PM radar remains fairly active with a line
of heavy showers and a few embedded thunderstorms from the
Greenbrier Valley south into North Carolina foothills. This line
will continue to trek across the Blue Ridge over the next few
hours before dying out around midnight. Storms look to remain
below severe limits although frequent lightning,m heavy
rainfall, and wind gusts upwards of 30 mph are likely with any
storm as they push on through. Beyond this line a few lingering
showers and pockets of drizzle cannot be ruled out as convection
off to the west across Kentucky and northeast Tennessee starts
to die out as it drifts east along the warm frontal boundary
slowly lifting north into our area.
Areas where we see rain due have a chance at some patchy dense fog
overnight with lows in the low to mid 60s in the west with mid to
upper 60s out east. Dewpoint values will also remain on the muggy
side of things in the mid to upper 60s.
By Sunday, the front starts to push north and west of our area.
Despite being in the warm sector with dewpoints back around 70
degrees the better forcing will be found to the north across the
Delmarva back into north central West Virginia. 18z model sounding
from NAMnest and HRRR show a weakly capped environment with
some dry air aloft signifying scattered convection with the
potential for localized downbursts. Current hi-res guidance from
NAMnest and HRRR continue to ping MLCAPE values of 2000-2500
j/kg with steepening mid level lapse rates of 6-7 degrees C/KM
and bulk effective shear values of 25-30 kts. PWATS will also
be on the order of 1.5 to 2.0 inches yielding efficient rainfall
from any convection that may develop. Per latest model guidance
confidence continues to increase in avoiding a widespread
severe weather event.
A few storms are likely to be strong to severe with localized
damaging winds and flash flooding concern mainly along and west
of the west of the Blue Ridge where a marginal risk for severe
weather exists. Storms will be fueled by highs in the low to mid
80s in the west with highs close to 90 in the east Sunday
afternoon. Convection should wane by late SUnday evening into
Sunday night as we lose the peak heating of the day.
Confidence remains high for temperatures and winds. Moderate
confidence in regards to storm coverage and cloud cover with the
front nearby.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 130 PM EDT Saturday...
Daily chances of showers and storms...
An area of upper level high pressure off the coast of the Carolinas
and an upper low/trough over the mid to upper Mississippi Valley,
will be the key players in the sensible weather across our region.
The position of the high and the low will help maintain a low level
flow of moisture off the Gulf of Mexico that will advect north, then
northeast into our region. While the best moisture will remain just
west of the region, there will be enough across our area so that
through daytime heating, we will see daily chances of afternoon and
early evening showers and storms across the region, especially
western sections.
Confidence in the above weather scenario is moderate to high.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 1245 PM EDT Saturday...
Daily chances of afternoon showers and storms continue with a
cold front arriving Friday into Saturday...
During this portion of the forecast, a compact area of low pressure
will race eastward from the central Rockies. This feature will help
to eject eastward the upper trough that will have been nearly
stationary across the Mississippi Valley. This upper trough and its
associated cold front will move towards and then across our region.
This is a transition that will take place from Wednesday into
Friday. Then on Saturday, a shortwave trough on the southern end of
the cold front will head northeast across our region. The result
will be increasing chances of daily afternoon showers and storms
Wednesday through Friday, with the best potential for a more robust
coverage across the region on Saturday.
Temperatures through the period will average right around normal for
this time of the year. Low temperatures will inch slightly higher
each day thanks to increasing dew points, but high temperatures will
inch lower thanks to more cloud cover and precipitation potential.
Confidence in the above weather scenario is moderate to high.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
As of 820 PM EDT Saturday...
Pockets of MVFR cigs and vsbys continue this evening from KLYH/KROA
back west to KLWB/KBCB/KBLF/KTNB where showers and storms look to
remain through at least 2z/9PM. Elsewhere scattered to broken VFR
stratocumulus remains from KDAN/KGSO back north to KCHO. All of this
activity is associated with a warm frontal boundary that looks to
slowly lift north into the area overnight into Sunday morning.
The front will reinforce mid to high level clouds overnight along
with a chance at a few isolated sprinkles or showers across the
region. Besides the shower chances, patchy MVFR to IFR fog is likely
late tonight into early Sunday morning. Highest confidence for this
would be at TAF sites that did see rain today. This includes
KBLF/KTNB/KBCB/KROA/KLYH and KLWB where multiple rounds of
thunderstorm activity rolled through. VFR conditions look to return
beyond 12-14z/8-10AM with pockets of MVFR cigs/vsbys developing with
scattered showers and storms after 16z/12PM.
Winds will remain light and variable overnight into Sunday
afternoon. The exception would be around any shower or thunderstorm
activity which looks to form beyond 16-18z/12-2PM Sunday afternoon.
Activity will be isolated to widely scattered with hi-res guidance
pointing toward the best opportunities for storms from KHSP/KLWB back
south to KBLF/KBCB. Storms could be locally strong at these TAF
sites with gusty winds, frequent lightning, and heavy rainfall.
Average confidence winds, ceilings, visibilities, and thunderstorm
chances heading into Sunday afternoon.
Extended Aviation Discussion...
Daily afternoon and evening showers and thunderstorms look to
continue for the Monday through Friday timeframe. Thunderstorm
activity will mainly be confined to the mountains Monday through
Wednesday as ridging starts to build in. Better chances for storms
arrive Thursday and FRiday as our next front nears the area.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AMS/SH
NEAR TERM...ET
SHORT TERM...DS
LONG TERM...DS
AVIATION...ET
Area Forecast Discussion
National Weather Service San Angelo TX
635 PM CDT Sat Jul 10 2021
...New AVIATION...
.SHORT TERM...
(This evening through Sunday)
Issued at 205 PM CDT Sat Jul 10 2021
A cold front will enter the Big Country late tonight. This will
bring a chance for scattered thunderstorms for locations that are
mainly north of I-20. Some of this activity could be strong to
severe with damaging winds and large hail being the main concerns.
Otherwise, look for little variation in temperatures as highs will
remain in the lower 90s for Sunday.
&&
.LONG TERM...
(Sunday night through next Saturday)
Issued at 205 PM CDT Sat Jul 10 2021
Chances for showers and storms continue into Sunday evening along
the front, perhaps becoming a little more widespread across the
Heartland and Concho Valley. Both the 12Z HRRR and TTU-WRF were
aggressive in showing a decent area of storms developing, with
other models like the NAMNEST were much less so. Will boost POPs
a little more for Sunday evening.
Otherwise a dry forecast for much of the upcoming week as the
main storm track shifts northward and high pressure aloft builds
across the area. Less clouds, more sun, and low level thermal
fields gradually warming all indicate that high temperatures for
the upcoming week will be higher as well. Highs in the low to mid
90s look on track, closer to the seasonal normals. Another upper
level trough will drop into the central and southern Plains next
weekend, perhaps close enough to give us another shot at least
isolated convection next weekend.
&&
.AVIATION...
(00Z TAFS)
Issued at 635 PM CDT Sat Jul 10 2021
06Z-12Z, scattered SHRA/TSRA may move into the Big Country,
potentially impacting KABI. Then, between 18Z today and 00Z Mon,
more scattered to numerous SHRA/TSRA may move through much of the
region, with low confidence in exact timing and locations. Any
SHRA/TSRA could bring heavy downpours resulting in brief
LIFR/VLIFR conditions, along with strong downdraft winds and large
hail. Otherwise, VFR conditions will continue through 06Z, then
MVFR to IFR CIGs will develop from south to north across locations
south of I-20 through 15Z, impacting KSJT, KSOA, KJCT, and KBBD.
Low confidence that the MVFR/IFR CIGs will reach KABI, so left it
out of that TAF site. 15Z to 18Z, conditions clearing/lifting back
to VFR. 18Z today to 00Z Mon, VFR conditions (other than the
potential SHRA/TSRA impacts noted earlier). Winds will be out of
the S to SW at 6-12 KT through 03Z, weaken to 3-7 KT between 03Z
and 16Z, then strengthen back to 6-12 KT through 00Z Mon, except
for N winds of 8-12 KT (with higher gusts) in the Big Country
which will come in behind a cold front after 21Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 73 91 71 92 / 10 40 30 10
San Angelo 71 93 71 94 / 0 30 30 5
Junction 71 92 71 92 / 5 10 20 5
Brownwood 72 93 71 92 / 5 60 60 20
Sweetwater 72 89 70 91 / 10 40 20 10
Ozona 71 90 70 91 / 5 20 20 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...24
LONG TERM....07
AVIATION...SJH
Area Forecast Discussion
National Weather Service Tulsa OK
950 PM CDT Sat Jul 10 2021
.DISCUSSION...
Strong to severe convection continues to slowly push southward across
east central OK and west central AR this evening. Moderately strong
instability perists south of the convection, and deep layer shear
remains strong enough to maintain some organization as it continues
southward this evening. Have been hesitant to remove counties from
the severe thunderstorm watch, as moderately strong instability
persists north of the primary convective band and south of the
approaching cold front. HRRR has been consistent in developing
additional convection in that air mass, and have seen indications of
that occurring for past hour or so. Severe threat probaby not real
high north of ongoing organized convection, but could be a strong to
severe storm develop given supporting parameters. Watch currently set
to expire at 11pm, but may need to be locally extended sern OK.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...69
Area Forecast Discussion
National Weather Service Las Vegas NV
210 PM PDT Sat Jul 10 2021
.SYNOPSIS...Major heat wave will peak across the region over the
weekend with long standing and all-time record high temperatures
being challenged or exceeded in some areas. Isolated thunderstorms
will continue to be possible in the afternoon and evening hours,
but mainly in the higher terrain and in northwest Arizona. Heat
will gradually moderate next week as high pressure weakens and
deeper monsoonal moisture moves into eastern areas.
&&
.DISCUSSION...Through next Saturday.
Through Tuesday...Intense high center with H5 heights greater than
597 dm will stay positioned over the southern Great Basin and Mojave
Desert. Extremely dangerous temperatures will continue to occur.
The heat product may need to be extended out one more day to Tuesday
for our western zones but we can cross that bridge either tonight or
tomorrow.
Modest monsoon moisture is in place across parts of southern Clark,
southern Mohave and eastern San Bernardino Counties. This moisture
will generally remain in place or get nudged slightly further west
and north through Tuesday; generally staying along and southeast of
I-15. Latest HRRR run continues to indicate isolated thunderstorms
in southern Mohave County into this evening, working as far west as
around Kingman before starting to weaken. Outflow easterly winds
from the storms have the potential of making it into the Colorado
River Valley between Lake Mohave and Lake Havasu. Winds speeds do
not look that intense maybe gusts up to 30 mph.
As the moisture seeps northward the threat of isolated thunderstorms
increases slightly Sunday into Tuesday. Any storms along and
southeast of I-15 should be wet, while elsewhere isolated dry
thunderstorms are possible over south central Nevada and Inyo
County. Will continue to monitor the need for any fire weather
headlines regarding dry lightning.
Wednesday and Beyond: Trough along the West Coast will allow H5
heights to retreat slightly during the period as the high center
shifts east toward the Four Corners region by next Saturday. This
will bring an end to the extreme temperatures as values return
closer to our mid-July normals. Southwest flow associated with the
trough will spread drier air in from the west limiting any chance
for showers and thunderstorms to Mohave County Thursday-Saturday.
&&
.CLIMATE...Listed below are a few climate locations showing both the
record high maximum and high minimum temperature for each location and
the year the record was last set for Saturday, Sunday and Monday.
LOCATION SAT-JULY 10 SUN-JULY 11 MON-JULY 12
(HIGH MAX) Record(year) Record(year) Record(year)
Las Vegas NV 114(2012) 116(1959) 114(2003)
Bishop CA 110(2002) 107(2020) 108(2020)
Barstow CA 115(1961) 115(2003) 115(2020)
Needles CA 121(2003) 120(2020) 124(1925)
Kingman AZ 111(2003) 110(1961) 111(2020)
Desert Rock NV 110(2002) 110(2012) 111(2020)
Death Valley CA 134(1913) 129(1913) 130(1913)
LOCATION SAT-JULY 10 SUN-JULY 11 MON-JULY 12
(HIGH MIN) Record(year) Record(year) Record(year)
Las Vegas NV 89(2002) 91(2012) 94(2020)
Bishop CA 71(1985) 70(2013) 69(1990)
Barstow CA 84(2013) 85(2002) 87(2012)
Needles CA 92(2002) 94(2012) 92(2019)
Kingman AZ 79(1913) 81(1906) 83(1925)
Desert Rock NV 81(1981) 81(1996) 81(2003)
Death Valley CA 100(1924) 105(1920) 107(2012)
&&
.AVIATION...For McCarran...Easterly or light and variable wind
expected into early evening. Speeds should stay at 8 kts or less.
After 02Z, typical south-southwesterly wind will develop and
continue overnight. Light easterly wind will develop again Sunday
with speeds 8 kts or less. Expecting more storm development over the
mountains west of the valley tomorrow. Outflow from the decaying
storms could impact the terminal late in the afternoon. Confidence
to low to include the forecast at this point. SCT-BKN150 during the
period.
Extreme temperatures are expected through the weekend, with
temperatures reaching 100 degrees each morning by 9-10 AM and
falling below in the 12-2 AM time frame. High temperatures will be
near 116 today and Sunday.
For the rest of southern Nevada, northwest Arizona, and southeast
California...Easterly outflow winds up to 25 kts could impact KEED
and KIFP early this evening as storms weaken to the east over Mohave
County. Gusty outflow winds from storms along the southern Sierra
crest may also impact KBIH with gusty westerly winds. Elsewhere,
isolated storms will dissipate this evening leaving behind partly to
mostly cloudy skies and typical nighttime down valley winds. Similar
conditions are forecast tomorrow with greatest thunderstorm threat
being over Mohave County and the southern Sierra crest.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
DISCUSSION...Pierce
CLIMATE...Peters
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