Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/10/22
Area Forecast Discussion
National Weather Service La Crosse WI
1025 PM CDT Sat Jul 9 2022
.DISCUSSION...(This evening through Saturday)
Issued at 151 PM CDT Sat Jul 9 2022
Key Messages:
- Low Rain Chances Sunday
- Cold Front Moves through the Region Sunday Night
- More Showers and Storms Possible Monday and Monday Night
- High Building across Late in the Week
Low Rain Chances Sunday:
About as perfect weather as it can get for a July Saturday...fairly
low humidity, light breeze, lots of blue sky, and seasonable
temperatures. The responsible surface high currently sits over the
Upper Great Lakes but will slowly retreat eastward heading into
Sunday.
A developing north-south oriented low level jet over the Plains
tonight will interact with an incoming shortwave and pool of higher
dewpoints to initiate a nocturnal complex of storms over North
Dakota late. While the shortwave will continue to advance eastward
on Sunday, the weakening LLJ will pivot clockwise into northern
Wisconsin. This may result in part of the decaying storm complex
diving southeastward into the forecast area towards midday. The
remaining convection is expected to weaken quickly as it encounters
the drier, more stable airmass overhead. In fact, some high-res
models show the activity fizzling out entirely before reaching our
area. The 09.12Z HRRR was most aggressive of the CAMs, bringing
fairly widespread rain through most of the area before drying out
late afternoon. For now, have introduced low end (20 percent) PoPs
mainly west of the Mississippi River. Temperatures should climb
slightly higher on Sunday with rising dewpoints making it feel a tad
more humid.
Cold Front Moves through the Region Sunday Night:
While the 09.12z models continue to show favorable 0-6 km shear for
supercell storms north of Interstate 90 on Sunday evening, there
continues to be a fairly sizable cap between 800 and 700 mb. This
greatly reduces the shear to less than 10 knots in the GFS and 20 to
30 knots in the ECMWF. At the same time, the instability will
gradually be waning as any storms along the front move into the
forecast area. The GFS and ECMWF 0-1 km mixed-layer CAPES are 1500
to 2500 J/kg during the evening and a 1000 to 1500 J/kg overnight.
It continues to look rather marginal for severe storms in our area.
If they did occur, hail and damaging winds would be the main threat.
If we happen to warm more than expected on Sunday, you might see a
storm become surface based and that would present a tornado threat
in north-central Wisconsin, but the confidence is very low that this
will occur.
More Showers and Storms Possible Monday and Monday Night:
A trough will move through the area on Monday afternoon and night.
Ahead of this wave, 0-1 mixed-layer CAPES will range from 500 to
1500 J/kg. The GFS has 0-6 km shear favorable for supercells, but
concerned that the shear is too strong for the amount of CAPE
available and storms may be sheared apart. The ECMWF has weaker shear
(less than 30 knots) so not as great of a severe storm threat.
High Building across Late in the Week:
The models are in general agreement that the ridge over the Central
Plains will build across the region late next week and continuing
into the weekend. However, still plenty of uncertainty on just how
much temperature will warm in the mid layers of the atmosphere. The
GFS remains much warmer than the ECMWF around 700 mb. This will
impact where there will be the potential for storms rounding the
ridge and how warm we will warm. Due to this uncertainty, did not
move too much away from the NBM at this time.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1025 PM CDT Sat Jul 9 2022
CIGS: SKC/SCT for most of the night with increase in mid clouds
during the day Sunday. Expect it to hold VFR.
WX/vsby: kind of a messy scenario without a clear-cut solution. CAMS
models take a storm complex out of the plains southeast Sun morning,
tracking it across the Upper Mississippi River Valley. How long it
holds together and its track vary with the HRRR the most aggressive
with impacts for KRST/KLSE. Later into the evening, more storms look
to spark along/ahead of a cold front and could near the TAF sites
before 06z. Again, the HRRR is the more aggressive of the short term
models. Hesitant to buy fully into the HRRR and will continue to
side toward a drier forecast - for now. Will keep close eye on
trends/models and adjust as needed.
WINDS: light southeast becoming more southerly and picking up into
the lower teens Sunday morning. Gusts in the lower 20 kts by the
afternoon.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Kurz/Boyne
AVIATION.....Rieck
Area Forecast Discussion
National Weather Service Bismarck ND
850 PM CDT Sat Jul 9 2022
.UPDATE...
Issued at 850 PM CDT Sat Jul 9 2022
The main story for this update is that while the overall threat for
severe weather tonight remains in place across most of western and
central North Dakota, the highest probabilities for significant
severe weather (i.e., 70 mph wind gusts and 2 inch diameter hail)
appear to be shifting south, focusing along and slightly north of
the I-94 corridor from the Montana border to the Missouri River.
Current radar imagery shows a discrete supercell over central
Montana located south of congealing convection that shows signs of
transitioning to more of a linear mode. This setup is generally in
line with recent HRRR iterations, which seem to favor more of a
discrete mode on the southern periphery of the larger scale forward-
propagating MCS. This thinking is also in line with lingering
concerns about MLCIN, which would be more of a determining factor in
storm mode rather than storm maintenance. The concern now is that
the strongest upper level flow appears to be shifting slightly south
of previous thinking, with the strongest effective bulk shear now
showing a greater area of overlapping with the pool of extreme
buoyancy on the order of 3000-5000 J/kg MUCAPE. If the southern
flank of the MCS does maintain more of a discrete mode, this would
increase the risk for very large hail, which could be in tangent
with the advertised wind gust threat ceiling around 70 mph. Further
north, the threat for severe weather still exists, but there now
appears to be a little more uncertainty on intensity and coverage.
If anything, the threat for large hail will almost certainly be
lower across the northern half of the state than the south.
A Severe Thunderstorm Watch has been issued for much of western and
parts of central North Dakota until 5 AM CDT. The Heat Advisory will
be allowed to expire on time.
UPDATE Issued at 644 PM CDT Sat Jul 9 2022
Little to no change in forecast thinking for the severe storm threat
through early Sunday morning. Some minor adjustments were made to
PoPs, driven by observational and recent model trends. While we will
continue to mention a slight chance of a discrete supercell
developing this evening, this potential will becoming increasingly
unlikely as diurnal heating begins to wane and MLCIN increases.
2330 UTC visible satellite imagery presents no imminent signs of
convective initiation. Furthermore, the surface wind field has
notably weakened over the past couple hours, reducing the
magnitude of the low level convergence that would likely be
required for CI.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 249 PM CDT Sat Jul 9 2022
Our attention through Sunday evening is on severe-storm risk, but
the greatest risk is overnight tonight. Key messages include:
* A slight (20%), conditional risk of severe storms in central ND
through this evening
* Scattered to numerous severe storms with potential clusters,
bowing segments, and supercells overnight tonight with risks of
large hail and damaging winds
* Potential for a few additional severe storms Sunday/Sunday
evening
As of 19 UTC, boundary layer recovery is well underway in the wake
of earlier convection, with the deepest moisture centered across
southwestern ND where stratocumulus is noted on satellite imagery
thanks to mixing of the moisture beneath a capping inversion. The
air mass through late afternoon and early evening will be marked
by dewpoints in the mid 60s to lower 70s F, with steep midlevel
lapse rates contributing to MLCAPE of 2000-3000 J/kg. Neutral to
subtle height rises will be ongoing, and some inhibition is apt to
remain in place through the diurnal heating cycle. However, broad
confluence exists in surface wind fields in central and north
central ND. MLCIN is also forecast to be minimal in forecast
soundings from some model cores. Differential mixing between the
stratocumulus in southwestern ND residual, but modifying outflow
from earlier convection also presents a non-zero probability for
convective initiation. Thus, we have retained a slight, 20%
probability of a thunderstorm over central ND through the early
evening in respect to a conditional-severe potential owing to deep
layer shear on the order of 40 kt in this thermodynamic setting.
Hodographs this afternoon and early evening display long, mostly
straight geometry, favoring potential large hail if any storms
do manage to develop.
We are continuing the Heat Advisory through this evening in south
central ND, as the combination of temperatures in the lower 90s F
and dewpoints around 70 F will likely still produce heat indices
around 100 F.
Early afternoon visible satellite imagery reveals subtle middle
and high-level clouds reaching western MT, marking the leading
edge of forcing associated with a more pronounced shortwave trough
that is expected to cross the region tonight into early Sunday.
We expect convection to develop ahead of this wave and mature
across central and eastern MT through this evening as it
encounters rich low-level moisture and increasing bouyancy with
eastward extent. CAMs have been consistent in this scenario, and
suggest storms crossing into ND in the 05-07 UTC time frame. The
downstream environment across western and central ND tonight is
forecast to be characterized by strong bouyancy with MUCAPE of
3000 to perhaps 4000 J/kg, and strong deep-layer wind shear on the
order of 50 kt. Moreover, low-level wind fields will strengthen
ahead of the shortwave trough, leading to comparatively larger
0-3-km shear on the order of 25 kt tonight compared to last night,
along with DCAPE near 1000 J/kg. This will favor a damaging wind
risk, and we are advertising gusts to 70 mph, though if an
organized bowing segment develops significant-severe gusts higher
than that could occur. However, there is some uncertainty in
convective mode tonight, as low- and midlevel warm air advection
ahead of the shortwave trough could lead to increasing capping
with time and with southward extent. If inhibition increases, some
more discrete, supercellular storms are possible, mainly on the
southern flank of convective complexes that move into the area out
of MT. If semi-discrete supercells end up as the dominant mode over
parts of the area in the stronger-capping scenario, the overall
severe risk could be geographically concentrated in an west to
east zone, but would also include potential for large to very
large hail. In contrast, if the midlevel warm air advection is
slightly less, or if the low-level moist layer deepens a bit more,
than inhibition may be less, which could enable a longer-lived,
intense bowing segment to impact a swath of western and central ND
late tonight into Sunday morning.
The 12 UTC HREF updraft helicity guidance captures what will
likely be the greatest overlap of the highest bouyancy, strongest
deep-layer wind fields, and weakest capping from west central ND,
roughly along the Highway 200 corridor, east all the way into
central ND. Note though that the higher-end threat ceiling could
extend southward somewhat, into the I-94 corridor, if the
aforementioned capping is weaker, or it could be relegated further
north if capping ends up being stronger.
A surface cool frontal zone will cross the area early Sunday with
the primary shortwave trough, shifting the largest bouyancy east
and likely ending the overnight/early morning severe risk by about
15 UTC. We are advertising a mainly dry forecast Sunday with highs
in the 80s F in the post-frontal environment, but lingering low-
level moisture will contribute to MLCAPE of 1000-1500 J/kg late in
the day and into Sunday evening. Another risk of strong to severe
storms will occur late Sunday afternoon into Sunday evening given
about 35 kt of deep-layer shear, with initiation possible ahead of
another shortwave trough, and/or with storms moving from southern
MT into southern ND in the evening. Overall hazard magnitudes will
be less -- on the order of quarter size hail and wind gusts up to
60 mph -- if storms do impact the area in this environment.
.LONG TERM...(Monday through Saturday)
Issued at 249 PM CDT Sat Jul 9 2022
The key message in the long term is for a much drier pattern to be
in place Monday through Thursday, along with increasing heat by
late week.
Early this week, northwest flow aloft is temporarily forecast as
the large-scale upper-level ridge to our south is suppressed for a
time. This will enable a cooler, breezy day Monday, with highs in
the upper 70s to lower 80s F, but a warming trend will begin on
Tuesday, and by mid to late week as the upper-level ridging builds
northward again heat will return to the area. The spread in NBM
members is a modest five degrees or so through the long term part
of the forecast, raising our confidence in widespread highs in the
90s F Wednesday through Saturday. Low-level moisture will likely
be maintained, leading to high humidity levels and the possibility
of needing heat headlines at some point. Global ensembles suggest
the ridge may dampen somewhat by late week into next weekend, but
display a relatively large spread in their simulations of how far
heights may fall, and to what degree impulses aloft may cross the
area in favor of convection. Still, there is enough concurrence
in that prospect for the re-introduction of slight chances of
storms again by late week into next weekend. However, the large-
scale flow prior to that, for most of the work week, favors a much
drier time period than what we`ve experienced recently.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 644 PM CDT Sat Jul 9 2022
VFR conditions are likely to prevail this evening. Strong to severe
thunderstorms are expected to quickly move from west to east across
North Dakota late tonight into Sunday morning. Higher probabilities
for storms exist at KXWA and KMOT, where TEMPO groups have been
introduced for significant visibility restrictions and wind gusts. A
brief period of strong easterly winds is possible behind the
departing storms early Sunday morning.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Hollan
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...Hollan
Area Forecast Discussion
National Weather Service Des Moines IA
632 PM CDT Sat Jul 9 2022
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Saturday/
Issued at 246 PM CDT Sat Jul 9 2022
Forecast Highlights:
-Beautiful Saturday, quiet and comfortable
-Mainly quiet Sunday, with possible showers and thunderstorms north
-Additional low chances for showers and thunderstorms, followed by
quiet weather for the rest of the upcoming work week
-Warmup expected late in the forecast period in the 90s across the
state
A pleasant Saturday continues this afternoon as an area of high
pressure slowly passes over the region, centered over northern
Wisconsin. Temperatures continue to increase as expected, currently
sitting in the upper 70s to low 80s, paired with lower humidity
values and light winds from variable directions as areas cumulus
fields develop across portions of the state. Thicker cloud cover
continued to linger over northwestern Iowa this morning into the
afternoon, though have since largely dissipated. The remainder of
the day will remain dry and comfortable, with temperatures expected
to increase slightly more through the rest of the afternoon in the
low to mid 80s. Quiet conditions are expected tonight with mostly
clear skies as lows fall into the 60s.
The high pressure system will push east out of the Great Lakes
region tonight into Sunday morning, as the upper flow pattern turns
quasi-zonal over the northwestern CONUS. Model guidance continues to
depict a weak shortwave and associated surface low pushing across
the northern plains into the Upper Midwest Sunday. Showers and
thunderstorms are possible with the passing front, moving through
Minnesota into northern Iowa Sunday evening. Looking at model
soundings, moderate instability and shear parameters exist, though
various deterministic models as well as the HREF ensembles suggest
dry air throughout much of the layer, paired with warmer
temperatures in the low to mid levels that may allow for capping to
limit storm potential. If any convection is able to develop, it
would be largely elevated with an overall low strong to severe storm
threat. The rest of Iowa looks to remain dry through the day, with
mostly sunny skies. Low level flow will increase out of the
southwest, leading to breezy conditions across the state. Model
soundings depict gusts ranging in largely between 20 to 25 mph,
isolated to 30 mph at times especially across the north. Resulting
warm air advection pushing into the state will bring in slightly
warmer temperatures, reaching into the 80s to low 90s, warmest in
western Iowa.
A stronger shortwave trough sinking south from Canada into the Great
Lakes region Monday morning will bring another chance for showers
and storms into Iowa. As the front sags south into Iowa through the
morning with increasing moisture, scattered showers and storms look
to develop across much of the region into the early afternoon.
Models seem to be struggling on the extent of the details in regards
to this system. The RAP and NAM guidance suggests that any morning
convection would fizzle out through the afternoon as dry air
overtakes the region, keeping storm chances mainly through the
morning. The GFS is more optimistic that showers and storms will
occur for most of Monday as moisture aloft remains over the region.
Overall instability and shear parameters are there to hint for at
least some severe potential, though the activity is depicted to
remain largely behind the front where ingredients are less
favorable. Any storms resulting from this system look to also fall
on the low end for strong to severe potential, but will keep a close
eye on this over the next few days.
Into Tuesday through the remainder of the work week, a broad area of
upper ridging over the western half of the CONUS is expected to push
east through the region. A mainly dry period of weather will come
with this, though long term guidance suggest a few perturbations
to move through as well, bringing some brief periods of showers.
Overall these look to be minimal in terms of impact, specific
details regarding each little system are uncertain at this time.
Temperatures are expected to warm through the week, especially
into Friday/Saturday as temperatures soar into the 90s with the
ridge overhead increasing southwesterly flow to much of the
Central Plains.
&&
.AVIATION.../For the 00Z TAFS through 00Z Sunday evening/
Issued at 632 PM CDT Sat Jul 9 2022
VFR conditions will prevail through the period at the terminals.
At present, FEW to SCT cumulus clouds with bases between FL030 and
FL050 will dissipate over the next few hours. As a warm front
lifts northeastward through Iowa on Sunday, will see an area of
lowered, but still VFR ceilings pass through in the morning to
early afternoon hours with winds becoming breezy from a southerly
direction.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Bury/Martin
AVIATION...Ansorge
Area Forecast Discussion
National Weather Service Grand Forks ND
908 PM CDT Sat Jul 9 2022
.UPDATE...
Issued at 908 PM CDT Sat Jul 9 2022
Decoupling is underway and CU fields are quickly dissipating.
There is still a cluster of showers/storms in southern Manitoba
that may clip the northwest angle later this evening/overnight
closer to forcing in Canada, however impacts would be limited and
the rest of our CWA is likely in the clear until much later
tonight/Sunday morning. I adjusted Pops/Wx/Sky to better reflect
trends this evening into the morning hours, and will continue to
monitor upstream trends/new data sources when full suite of 00Z
guidance comes in later this evening.
UPDATE Issued at 652 PM CDT Sat Jul 9 2022
Axis of 3500 J/KG ML CAPE across our western CWA and effective
shear in the 30-40 kt range according to RAP analysis still
raises the possibility for severe convection "IF" initiation were
to actually take place. CIN had weakened but surface convergence
near the few weak boundaries in our area has at most support ed
flash cut and a few earlier orphaned anvils. Now trends aren`t
really any better as decoupling will be getting underway in a few
hours. Latest HRRR still shows possible initiation in the Devils
Lake Basin in the next few hours, but the CU field in that area
really isn`t any more remarkable than anywhere else. In absence
of any organized forcing the potential is very isolated at this
point and we may be seeing the window close over the new few
hours. Focus will then turn to what may be the better potential
for severe as a possible upstream MCS develops and tracks east
into our CWA after 09Z (CAMs still supporting this potential).
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 220 PM CDT Sat Jul 9 2022
Convection, its placement and timing, the main challenges and
would be impacts in the next 36 hours. Three distinct periods of
concern seem to be most apparent. The first is this afternoon and
evening within the low level convergence zone extending along the
northern valley with west to southwest winds nosing into southerly
low level flow in the wake of the morning convection. With full
sun low level lapse rates have responded with less than favorable
mid level lapse rates. Will need a kicker to initiate convection
to overcome the weaker mid level lapse rates and 500mb ridging
with water vapor imagery not showing much of a indicator of lift.
That said given model soundings near the International border
between Langdon and Cavalier the effective shear of 40 to 50kts
and ML Cape nearing 2000J/kg any storm that can develop has the
potential to become severe with wind, hail and tornado as a
possible threat. Again this is a conditional threat given
development.
The second period of concern will be overnight into tomorrow
morning as a mature MCS pushes across ND with convection entering
the western FA after midnight per timing of CAMs. Question of
intensity and coverage exists with the best chances for severe
based on associated updraft helicities based on the CAM output
across the northern half of the FA. Winds and possibly hail will
be the biggest threat.
Redevelopment tomorrow is the third period of concern with
attention on any outflow boundaries ahead of the approaching cold
front. Extra attention will need to be watched especially where
surface based instability can develop tomorrow. All severe
hazards possible tomorrow with plenty of uncertainties with
details to be refine after the overnight convection shows its
hand. Cold front timing does suggest NW winds push across the
area tomorrow afternoon with severe threat pushing SE with it
clearing the area by evening.
.LONG TERM...(Monday through Saturday)
Issued at 220 PM CDT Sat Jul 9 2022
Northwesterly flow will return to the area to start this long
term period. Precipitation will push out of our east on Monday and
into Tuesday morning, and less moisture will remain after the
cold front scours out the area, lessening precipitation chances
mid-week. High temperatures on Monday and Tuesday will be in the
upper 70s and low 80s.
A ridge is already progged to build back into the upper levels by
mid week according to ensemble guidance. This will warm our
temperatures into the low to mid 90s for daytime highs. With this
ridge comes a short period of no precipitation. However, this
doesn`t last long as the ridge will begin to flatten into next
weekend, allowing clipper systems to push through the area.
The weekend will continue to be warmer, with a decent chance for
some thunderstorms on Friday and Saturday afternoons with those
clipper systems. Confidence is lower on saying if these could be
strong or severe, as it is just too far out temporally to resolve
details like that in the guidance. We will continue to monitor the
forecast as it gets closer in time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 652 PM CDT Sat Jul 9 2022
VFR conditions should prevail through the TAF period across
eastern ND and northwest MN. Main aviation concern will be related
to potential showers/thunderstorms, with minimal (isolated)
coverage over the next few hours. Better chances arrive after 09Z
in eastern ND as a thunderstorm complex may move out of central ND
through 12-15Z and how far this makes it with impacts still
uncertain. Then redevelopment may be possible through the
afternoon as a cold front moves thorugh the region with better
chances transitioning east (mainly northwest MN). Strong to
severe thunderstorms are possible if anything develops, but direct
impacts at terminals are uncertain during the TAF period.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
$$
UPDATE...DJR
SHORT TERM...JK
LONG TERM...AK
AVIATION...DJR
Area Forecast Discussion
National Weather Service New Orleans LA
649 PM CDT Sat Jul 9 2022
...New UPDATE, AVIATION...
.UPDATE...
Issued at 641 PM CDT Sat Jul 9 2022
Trimmed down PoPs for now through tonight based on current radar
trends and since sunset will be coming soon. Otherwise the rest of
the forecast still currently on track. -BL
&&
.SHORT TERM (Now through Sunday Night)...
A fairly benign afternoon out there with the exception of a few
isolated shower and thunderstorms. Moderate instability has been
realized, however, the mid levels appear to be just a bit on the
dry side overall limiting the vertical convective growth. That
said, it is a HOT one across the region with heat index values
easily reaching 105 to 110 respectively across the region.
Going into the overnight, we are still monitoring the potential
MCS development upstream. The H5 flow (generally meridional at
this juncture) should allow for any complex of convection to slide
southward toward our region. The primary question is how far to
the west will the complex develop/build. Models are still favoring
generally along and east of the I55 corridor. However, HRRR show
additional westward building/maintenance of the MCS, which could
lead to much of the CWFA receiving some shower and thunderstorm
activity in the predawn hours. With the activity struggling west
of I55 this afternoon and the ridge firmly in place to our west,
will continue to advertise the best potential along and east of
I55. SPC continues the marginal categorical risk with winds being
the main focus. Secondary concerns would be the potential for
localized flooding, especially in urbanized areas with PWATs
exceeding 2 inches. Rainfall rates in excess of 4" cannot be ruled
out. That said, the transient nature of the complex may help
limit the impact just a bit tonight.
On Sunday, the front should make it to/through the region then
stall. This will lead to increasing shower and thunderstorm
chances, especially when compared to the last few days. Again, a
strong wind gust or two will be possible in the more robust
updrafts, but the main focus will eventually turn toward hydro
concerns. Temperatures also look to be mitigated by rain and
clouds, so didn`t continue a heat advisory for Sunday.
.LONG TERM (Monday through Saturday)...
Going into the new workweek, an active period looks to take shape
across the forecast area as a cold front stalls over or just south
of our region into the northern Gulf of Mexico. This boundary
will likely initiate additional shower and thunderstorm activity
with the best potential occuring during the diurnal cycle (night
over the waters and daytime over land zones). QPF through the next
week is a bit elevated with most areas generally along I10/12
receiving 2-4 inches with locally higher amounts possible. Closer
to the immediate Louisiana coast, there could be 4-6 inches...and
with convection there is always a possibility of locally higher
amounts. Antecedent conditions are still a bit on the dry side,
however, we`ll continue to monitor for the potential for elevated
hydro concerns throughout the week. With a tropical airmass over
the region, WPC tends to agree with categorical EROs of marginal
and slight respectively early in the period.
The globals begin to diverge toward mid to late week. The GFS
suggests that the bulk of the energy associated with the old front
will begin to shift west around the southern periphery of the
central US H5 ridge, away from our region. This would suggest
lessening of POPs/QPF just a bit. However, this seems to be an
outlier with the other globals indicating that much of the energy
may hang around as steering remains very weak as the region should
reside within an upper level weakness between the aforementioned
ridge to our northwest and the Atlantic subtropical ridge to our
east. Overall, not much change to the forecast from the previous
with continued higher end POPs/QPF and slightly lower temps due to
rain/clouds.
&&
.AVIATION...
(00Z TAFS)
Issued at 641 PM CDT Sat Jul 9 2022
Primarily VFR conditions will continue now through late tomorrow
morning into the early afternoon hours. Took out mentions of rain
and thunderstorms the coverage has significantly decreased for
tonight. Convection will return again tomorrow though, so any
terminal directly impacted by a storm could see decreases in
visibility or ceilings but otherwise it should remain VFR for the
forecast period. -BL
&&
.MARINE...
Mainly favorable marine conditions outside of convection across
the local Gulf and Lake waters. Speaking of convection, a cold
front will continue to move toward our region through the
remainder of the weekend and into the start of the new workweek
then stall over or near the area. This will likely provide a focus
for shower and thunderstorm development. Expect locally higher
winds and seas in or around the strongest convection.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 75 93 74 93 / 50 60 30 40
BTR 78 94 75 93 / 30 60 40 60
ASD 76 93 75 92 / 50 70 60 70
MSY 79 92 77 89 / 30 80 60 70
GPT 78 92 76 89 / 60 80 60 70
PQL 77 90 75 87 / 60 80 60 70
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory until 8 PM CDT this evening for LAZ034>037-039-
046>048-056>058-071-076-079>086.
MS...Heat Advisory until 8 PM CDT this evening for MSZ068>071-077-
080>082.
GM...None.
&&
Area Forecast Discussion
National Weather Service Reno NV
109 PM PDT Sat Jul 9 2022
.SYNOPSIS...
Typical summer weather through this weekend with warm temperatures,
afternoon breezes, and areas of smoke from nearby wildfires. Plan on
temperatures heating up to above average Sunday into next week, with
values around 100 degrees for western NV valleys. A few afternoon
thunderstorms are possible next week as monsoon moisture arrives.
&&
.DISCUSSION...
SUMMER HEAT: Near normal temperatures this afternoon will begin to
warm considerably tomorrow as high pressure expands across the West.
Monday and Tuesday will be the hottest days of the week, but while
it will be seasonably hot, we won`t be near records (e.g. KRNO
records are 108|104). Blended model guidance still shows around a
35- 45% chance of KRNO hitting 100 degrees Monday or Tuesday. Plan
on moderate risk for heat sensitive groups or those who lack
effective cooling options. Thankfully, temperatures will cool off
overnight, which will mitigate heat risk a bit.
WILDFIRE SMOKE AND HAZE: Primary smoke contributor appears to be the
actively burning Washburn Fire near Yosemite. Latest HRRR
simulations indicate another push of smoke will impact areas south
of Interstate 80 this evening. Mono County will suffer from the
worst of it, since it is directly downwind of the fire. I wouldn`t
be surprised to see some smoke impacts into the Tahoe Basin and even
into northeast California late tonight into Sunday as the flow turns
more easterly. This is all highly dependent on the amount of smoke
produced by the fire. Keep an eye on www.airnow.gov for the latest
air quality conditions during these periods of haze/smoke.
THUNDERSTORMS: Hot temperatures Monday will result in some cumulus
buildups along the high terrain, but we aren`t expecting any
thunderstorm possibilities until Tuesday. Simulations continue to
show a weak, subtle shortwave sweeping through the western edge of
high pressure over the Sierra and western Nevada on Tuesday.
Heating, upper level instability, and sufficient moisture will be
enough for slight chance of thunderstorms for the Eastern Sierra
north along the Sierra Front towards Susanville and the Oregon
border. Unfortunately with fast-moving upper level lift, such as
this shortwave, storm nature will likely be high-based, with little-
to-no rainfall and a higher rise of strong gusty/erratic outflow
winds. On Wednesday, chances for afternoon thunderstorms (10-20%)
remain for areas along and east of the Sierra Front. Our local
afternoon westerly zephyr winds may help to provide convergence for
storms to form. By Thursday, thunderstorms chances will be dwindling
as dry, southwest flow increases ahead of an incoming trough to the
Pacific Northwest. There may be enough residual moisture for
thunderstorm chances east of Highway 95 and south of Highway 50, but
this will depend on how far south the trough advances southward.
-Edan
&&
.AVIATION...
Areas of smoke and haze from the Washburn Fire near Yosemite are
already affecting the Carson Valley. Light and variable winds
will pick up and turn westerly from 21-04z, with gusts 25-30 kts.
Latest HRRR smoke guidance suggests this flow switch will advect
smoke out of the Carson Valley, but push smoke into Mono County,
affecting the KMMH terminal during this period. Winds are expected
to turn more easterly beyond 04z and potentially push smoke back
into the Carson Valley and Tahoe Basin, affecting KMEV-KCXP-KTVL
until around 11z. Smoke may briefly lower ceiling heights in
affected areas. Depending on fire activity and suppression
progress, smoke and haze impacts may continue tomorrow.
Looking ahead, hot temperatures midday Monday-Wednesday raise
density altitude concerns across the region. Thunderstorms are
possible Tuesday-Thursday across the eastern Sierra and western
Nevada. Otherwise, typical afternoon breezes are expected this week.
-Whitlam
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Blacksburg VA
827 PM EDT Sat Jul 9 2022
.SYNOPSIS...
A moist frontal boundary will slowly drop south tonight.
Showers are likely tonight and Sunday, then as brief high
pressure builds Monday dry weather is expected. Another front
arrives midweek with more showers and storms.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 810 PM EDT Saturday...
Threat of severe thunderstorms has ended...
Slow moving front was gradually pushing south and has reached
extreme southern Virginia and northern North Carolina. With the
better instability to the south of the boundary, the threat of
severe thunderstorms has also moved south.
From this point the main piece of shortwave energy to eject
from the lower Ohio River Valley crosses the central
Appalachians by Sunday morning. This will result in a
continuation of scattered showers and perhaps a thunderstorm
overnight. Will continue to maintain categorical PoPs, but
again not everyone will see the rain while most see quite a bit
(locally up to two inches).
12z guidance from the NAMnest, ARW, RAP, and HRRR continue to
depict this feast or famine type of scenario as well. With PWATS
ranging between 1.76 inches (12z RNK sounding this morning to
2.92 inches (12z IAD sounding), we can bank on some pretty
efficient rainfall and localized flooding concerns. For now
opted to maintain a mention of localized flash flooding in the
HWO compared to a short fused flash flood watch due largely in
part to rainfall amounts over the last 24 to 36 hours and the
the overall pattern of the last few days.
With that said, models continue to focus upon the VA/NC
Piedmont, southern Blue Ridge, and southern Shenandoah Valley
for the heaviest rainfall amounts tonight and Sunday. Amounts
of a 0.5 inches to 1.25 inches are likely in these areas with a
few pockets of 2+ inches along the higher ridges as a deep easterly
fetch pulls more moisture into the east side of the Appalachians.
Guidance continues to show pockets of drizzle, fog, and
stratiform rain north of the VA/NC line through Sunday morning.
Showers and isolated storm chances will remain across the VA/NC
Piedmont and North Carolina mountains the longest with southeast
West Virginia and the southern Shenadoah Valley likely to dry
out first.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
As of 155 PM EDT Saturday...
A cold front will move south into the Carolinas Sunday night.
Surface high pressure will also wedge south behind the front and
linger through Monday night. This wedge will keep the area dry
through the period.
Cool dry air (dew points in the upper 50s to low 60s) will be the
main feature of this wedge. Lows will dip into a more comfortable
range each night with reading from the upper 50s to mid 60s. Dry air
and a high summer sun angle should send Tuesday`s temperature into
the 80s across the mountains and lower 90s over the foothills and
piedmont.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 155 PM EDT Saturday...
The area will be in between a cold front approaching from the
northwest (Ohio River Valley) and the old wedge boundary retreating
to the north (Carolinas) as a warm front. With the assistance of an
upper level trough swinging across the upper Mississippi and Ohio
River Valleys late Tuesday, the cold front will drift south over the
area Tuesday night, stalling along the VA/NC border Wednesday. A
second drier front will move across the region Wednesday, clearing-
out the rain and high humidities for Thursday and Friday.
Temperatures will remain warm and muggy until the second frontal
passage Wednesday night. Temperatures and a chance for storms return
sometime next weekend.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 815 PM EDT Saturday...
A cold front will continue to move south tonight and Sunday
through the Carolinas and Tennessee Valley. Models and Bufkit
forecast soundings were in good agreement about widespread
IFR/LIFR stratus and MVFR fog developing this evening and
persisting well into Sunday morning. Areas of light to moderate
rain are expected, especially along and east of the Blue Ridge
as deep easterly flow develops before 06Z/2AM. Most ridges will
be in the clouds tonight and Sunday morning.
Ceilings will slowly lift from north to south on Sunday
afternoon. Do not have local TAF sites improving back to MVFR
until 20Z/4PM at the earliest. KBCB may not get to MVFR before
the 00Z end of the TAF forecast period.
Winds will be from the east to northeast behind the front
tonight and Sunday. Some gusts up to 20 knots are possible at
higher elevations north of KROA and at KLYH and KDAN overnight.
Above average confidence for ceiling and wind.
Average confidence for visibility
Extended Aviation Discussion...
Ceilings will continue to lift on Sunday night as a relatively
drier air mass works into the region.
Monday weak high pressure drifts over the area with mostly
MVFR-VFR conditions, especially by afternoon.
Showers and thunderstorms changes return by midweek with yet
another slow moving cold front which will bring periods of sub-
VFR conditions once again.
Overnight fog is expected each night from Tuesday through
Thursday due to moist ground and recent rainfall and relatively
high dewpoints continuing in the 65-70 degree range.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...ET/WP
NEAR TERM...AMS/ET
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...AMS