Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/23/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
845 PM CDT Sat Jul 22 2023
.UPDATE...
Issued at 843 PM CDT Sat Jul 22 2023
Overall forecast is doing fine but did adjust Sky grids for
elevated smoke through Sunday, and also lowered temps at ABR just
a touch for cold air drainage late tonight.
&&
.SHORT TERM...(This Evening through Sunday Night)
Issued at 231 PM CDT Sat Jul 22 2023
A weak shortwave currently tracking southeastward across western
South Dakota is producing isolated shower and thunderstorms west of
the Missouri River valley. Isolated thunderstorms have developed
over the far SE CWA, or mostly southeast of the CWA. All the
convection should exit the CWA later this evening. Another
shortwave may drive southeast across the region during the early
morning hours on Sunday, 11-14Z, with a low probability of pcpn.
The 17Z HRRR and CONSshort, as well as the 18Z ECAM support
isolated showers Sunday morning between the Missouri and James
River valley.
Hot temperatures should move into the area Sunday afternoon behind
the shortwave. 925 mb temperatures soar into the upper 20C to the
lower 30C, which is above the 75th percentile. Based on possible 925
mb and 850 mb temperatures, analogs suggest highs should should the
upper 80s, to the lower 100s. The James River valley should warm
into the mid 90s. As of now, heat indices will remain below 100
degrees. Another shortwave embedded within northwest flow may
interact with a 30-40 knot LLJ to produce showers and thunderstorms
over the far eastern CWA late Sunday night into Monday morning.
.LONG TERM...(Monday through Saturday)
Issued at 231 PM CDT Sat Jul 22 2023
No changes in the models overall large scale pattern heading into
the work week. Still expecting rising heights and a building ridge
to be the main theme through midweek. As such, no changes in the
early to mid week message - hot conditions are expected. Hot, but
definitely not record breaking heat. NAEFS/EC standardized anomalies
are generally less than 1.5 for 850 mb temperatures, peaking just
under 2.0 on Wednesday. Additionally, no signal from the EFI shift
of tails as to a large number of ensemble members signaling an
extreme event. NBM probability of exceeding 100 degrees on Wednesday
is greatest over the Missouri River Valley (~60%), around 50% across
the James River Valley and less than 20% for northeast South Dakota
and west central Minnesota. Relatively cooler temperatures (although
still above normal) are expected for the later half of the workweek
and into the weekend. Precipitation chances generally revolve around
shortwave energy, and as such, confidence in timing and location is
low. Warm air aloft/capping will largely be a limiting factor as
well, but periods of low coverage (~20% chance) thunderstorms do
exist in the Wednesday afternoon/night and Thursday afternoon/night
time frames.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 610 PM CDT Sat Jul 22 2023
Terminals KABR,KATY,KPIR,KMBG
VFR skies/vsbys are expected through tonight.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TDK
SHORT TERM...SD
LONG TERM...Serr
AVIATION...TDK
Area Forecast Discussion
National Weather Service Amarillo TX
634 PM CDT Sat Jul 22 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Sunday night)
Issued at 152 PM CDT Sat Jul 22 2023
Northwesterly flow is expected to still hold through the late
evening hours with models expecting another short-wave to push
through and create one more chance at active weather for the day.
Most high resolution models do expect some form of showers and
thunderstorms to make their way across the Panhandles this
evening. However, the intensity and spread of these storms is
still something that has been heavily debated. Currently the NAM
nest and the RAP have been backing MLCAPE values that range 1000
to just a little over the 2000 J/kg mark, alongside 0 to 6 km bulk
shear greater than 30kts. These values combine with the cooler
500mb temperatures seen, would be enough to support hail growth up
to an inch and half. However, there have also been signs that
winds may be the bigger threat for the day with DCAPE pushing past
1500 J/kg for most of the Panhandles as well as some models
presenting inverted V soundings in previous runs.
As it stands, the main severe threat may just boil down to where
the thunderstorms originated from. If they start in the west and
move in from Eastern New Mexico, then conditions are better suited
for a line of storms with winds up to 70 mph as our main threat.
However, anything that move into the north out of Kansas has a
better setup to be more discreet and produce hail. Currently,
latest high resolution runs are more in favor of the wind threat
out of New Mexico, but there are a few that still see some
thunderstorms make their way south during the early portions of
the overnight. Regardless, chances and opportunities should begin
to dwindle the further we get into Sunday as the 500mb high
pressure center starts to shift more eastward. As for Sunday
itself, look for much drier weather for the day with afternoon
high temperatures quickly returning back to the high 90s.
Scoleri
&&
.LONG TERM ...
(Monday through next Friday)
Issued at 152 PM CDT Sat Jul 22 2023
An upper level ridge of high pressure is expected to be centered
generally over New Mexico from Monday through Friday. This will
keep the Panhandles in a north to northwest flow aloft. There are
some models that extend an arm of this ridge across the Panhandles
after Wednesday, but the for the most part the center of the high is
expected to stay across New Mexico. This ridge looking like a
"dirty" ridge this week, meaning that there will still be
thunderstorms within the center of the high. So, we could see
thunderstorms in our northwest just about any day between Monday and
Friday. Right now we are only mentioning them Tuesday through
Thursday in the late afternoon and nighttime hours as this appears
to be the more likely timeframe.
High temperatures are going to warm up for this upcoming work week
with most spots getting up to around 5 degrees either side of 100
for most days.
&&
.AVIATION...
(00Z TAFS)
Issued at 623 PM CDT Sat Jul 22 2023
TAFs remain VFR for this period. Winds will generally be veering
from southwest to southeast at 15kts. There is still a slight
chance for thunderstorms at all sites tonight; however, our
confidence is too low to mention them at this time. We will
monitor for a potential shift in trends, and amendments may become
necessary if chances increase.
Rangel
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 66 97 70 101 / 30 0 0 0
Beaver OK 65 94 70 100 / 20 0 0 0
Boise City OK 61 94 66 100 / 20 0 0 0
Borger TX 68 99 72 104 / 30 0 0 0
Boys Ranch TX 66 99 70 103 / 50 0 0 0
Canyon TX 66 96 68 100 / 30 0 0 0
Clarendon TX 67 96 71 100 / 20 10 0 0
Dalhart TX 61 95 65 100 / 30 0 0 0
Guymon OK 62 95 67 101 / 20 0 0 0
Hereford TX 65 98 68 101 / 40 0 0 0
Lipscomb TX 65 95 70 101 / 20 0 0 0
Pampa TX 66 94 70 100 / 30 0 0 0
Shamrock TX 66 95 70 100 / 20 10 0 0
Wellington TX 67 97 70 102 / 20 10 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&
$$
SHORT TERM...11
LONG TERM....15
AVIATION...55
Area Forecast Discussion
National Weather Service Boise ID
849 PM MDT Sat Jul 22 2023
.DISCUSSION...Convection is producing gusty winds over the
southeast portion of the CWA, generally from central Owyhee
County east through Twin Falls County...and these showers (lots of
virga as well) are moving northeast. These gusts should continue
until around midnight, but gusts will weaken as temperatures
begins to cool. More showers and thunderstorms (along with more
virga) are expected tomorrow, and the area of coverage will expand
north and west. No update at this time.
&&
.AVIATION...Mainly VFR and mid/high clouds. High-based virga or rain
showers with isolated lightning for southwest/south-central Idaho
(including KTWF-KJER) through Sun/05Z. Activity capable of outflow
gusts to 30-40 kt and blowing dust. After Sun/19z, activity will
return to southwest/south-central Idaho, with a threat of gusts to
40-50 kt. Low confidence for activity to impact SE Oregon, but
cannot rule it out. Otherwise, high density altitude due to hot
afternoon temperatures. Areas of degraded visibility from wildfire
smoke/haze. Surface winds: variable 12 kt or less, then SW to NW 10-
20 kt Sunday afternoon. Winds aloft at 10k feet MSL: S-W 10-20 kt.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Monday night...
A seasonably strong anticyclone persists near the Four Corners,
leaving the interior Pacific Northwest situated within
southwesterly flow aloft. Monsoonal moisture will advect northward
across the Great Basin and elevate thunderstorm chances for parts
of southern Idaho Sunday and Monday.
*HEAT: Near-record 500-mb heights observed this morning continue
to support well above-normal temperatures today through Monday.
Temperatures will cool slightly as Saturday is expected to the
peak of the current heat episode, but will remain hot.
Probabilities of triple digit high temperatures are 70-90% on
Sunday and Monday across the Treasure and Magic Valleys. In
eastern Oregon, more significant cooling is expected Monday, with
only localized areas approaching 100 degrees. A Heat Advisory
remains in effect across much of the area Sunday, and for much of
southwest and south-central Idaho Monday.
*FIRE WEATHER: A Red Flag Warning is in effect Sunday and Monday
for far southwest Idaho and southeast Oregon for gusty winds, hot
temperatures, and low humidity. An approaching weak cold front
will bring an increase to winds, with gusts peaking at 30-40 mph
amidst minimum RH values in the single digit to low teens.
Reference RFWBOI and FWFBOI products for more detailed
information.
*THUNDERSTORMS: Thunderstorm chances tonight are virtually zero
(<5%), but will increase across the Magic Valley to 20% on Sunday
afternoon. Mid-level moisture will advect from the south and west
through Monday morning, with the primary focus of thunderstorm
activity across southeastern Idaho. There is some signal in HREF
ensemble guidance for weak convection occurring early Monday
morning across the Upper Treasure Valley and Magic Valley, but
given the lack of low-level moisture, this will most likely be in
the form of virga if it materializes. Thunderstorm chances on
Monday will be very similar to Sunday - primarily confined to the
Magic Valley and vicinity.
*SMOKE/HAZE: Wildfires across the region continue to lead to
localized areas of elevated smoke and haze. In the near-term,
fires across Oregon and southern Washington may affect eastern
Oregon. Guidance from the HRRR smoke model suggests some uptick
in smoke from Montana may drift southward Sunday into southern
Idaho.
LONG TERM...Tuesday through Saturday...
Only subtle changes synoptically will occur as the expansive
summer-time upper ridge gradually shifts eastward, and a colder
upper-low remains fixed over southwestern Canada. The most
notable change for the interior Northwest will be a slight
reduction in mid-level heights, and consequently, cooler
temperatures. Tuesday will see a 5-10 degree cooldown area-wide,
with highs only reaching the mid-90s in the warmest locations. A
gradual warmup may occur later in the week, but temperatures will
be sensitive to the actual placement of the mid-level anticyclone
over the Southwest amidst a tight height gradient in the Pacific
Northwest. Regardless, highs should generally remain in the mid-
upper 90s into this weekend. Monsoonal moisture is also expected
to remain shunted to the east amidst the stronger flow aloft.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Heat Advisory until midnight MDT Sunday night
IDZ011>016-029-030-033.
Red Flag Warning from 3 PM Sunday to 9 PM MDT Monday IDZ423.
Heat Advisory until midnight MDT tonight IDZ028.
OR...Heat Advisory until midnight MDT /11 PM PDT/ Sunday night
ORZ063-064.
Red Flag Warning from 3 PM MDT /2 PM PDT/ Sunday to 9 PM MDT /8
PM PDT/ Monday ORZ636-637.
Heat Advisory until 11 PM PDT this evening ORZ061.
&&
$$
www.weather.gov/Boise
www.facebook.com/NWSBoise
www.twitter.com/NWSBoise
DISCUSSION...SP
AVIATION.....SH
PREV SHORT TERM...JR
PREV LONG TERM....JR
Area Forecast Discussion
National Weather Service Duluth MN
624 PM CDT Sat Jul 22 2023
.MESOSCALE UPDATE...
Issued at 606 PM CDT Sat Jul 22 2023
Storm activity continues to dissipate early this evening, with
only some slight persistent cumulus bubbling over Koochiching,
Itasca, and northern Cass Counties where the best low level lapse
rates remain. However, with the best daytime heating starting to
go away, the tighter upper level vort max moving east, thick
smoke aloft pushing in across northwest Minnesota, and the
atmosphere being fairly worked over from all the activity through
the day today - not to mention poor mid level lapse rates,
generally expect this dissipating trend to continue. The
occasional storm that does manage to fire yet could have some
small hail in it, but the primary threat for the next hour would
be winds that come out of collapsing cells, possibly up to 40 mph.
MESOSCALE UPDATE Issued at 334 PM CDT Sat Jul 22 2023
Thunderstorms over north-central Minnesota appear to be
overachieving expectations based on the latest RAP13 analysis. A
compact vort max over northern St. Louis County per GOES-E water
vapor imagery appears to be generating a little more effective
shear than the RAP analysis suggests, likely closer to 35 to 45
knots. One storm over northern Itasca County produced ping pong
ball to tennis ball size hail over the past hour. We expect the
severe storm potential to propagate southward as the vort max
advances south-southeast over the next several hours.
RAP analysis suggests 1500-1750 J/kg of MLCAPE over that area
which should progress farther south with daytime heating. The
storms are moving into the rain and cloud shielded area from this
morning`s storms, and there may be a temporary weakening over the
next hour or so.
&&
.DISCUSSION...(This evening through Friday)
Issued at 158 PM CDT Sat Jul 22 2023
Summary: Scattered to numerous showers and thunderstorms are
expected today. A few storms this afternoon into the early evening
may become strong to severe, capable of producing damaging winds to
60 mph and hail up to 1 inch in diameter. The area of greatest
concern for severe weather today will be just west of the I-35
corridor into northwest WI. Additional chances for showers and
thunderstorms will arrive late Sunday afternoon and occur
periodically into Monday. Otherwise, the main story this upcoming
week will be the very warm to hot temps.
The synoptic pattern today has a large ridge centered over the
Intermountain West and a trough located over the eastern half of the
CONUS. With the CWA positioned downstream of the ridge, a shortwave
has been propagating southward from the Manitoba/Ontario Border into
northern MN. This shortwave will be the feature of interest today,
developing scattered to numerous showers and thunderstorms along a
sfc trough. Similar to yesterday, diurnal instability will be
fairly favorable. MUCAPE values this afternoon per hi-res models
will be around 1000-1500 J/kg on the high end. While instability
will be similar to yesterday, the increased winds associated with
today`s shortwave will result in slightly more organized
convection.
0-6 km bulk shear in the CWA this afternoon is expected to be around
30 knots, with effective bulk shear values from the RAP showing 25-
30 knots. The increased organization this shear is bringing to the
CWA has already been observed this morning into the early afternoon,
with convection having a longer duration compared to what was seen
yesterday. Due to the better kinematics today, strong to severe
storms will be possible from just west of the I-35 corridor into
northwest WI. Hi-res model soundings show that the storms today will
be relatively high-based above an inverted-V profile with steep 0-3
km lapse rates. This is supportive for potential damaging winds up
to 60 mph, especially underneath collapsing cells. Large hail up to
1" is also a concern this afternoon. However, the thin CAPE profiles
will limit hail growth somewhat due to entrainment. Severe potential
will begin to rapidly drop off late this afternoon into the evening
as the sfc trough continues to progress southeast.
Conditions tonight will be fairly quiet following the departure of
the showers and storms. Models suggest that patchy fog will be
possible, especially in areas that see rain this afternoon.
Conditions on Sunday will be more quiet, with a chance for isolated
diurnal showers and storms in the afternoon as weak isentropic
ascent occurs. Periodic chances for showers and storms will occur
from Sunday evening into Monday as several weak shots of vorticity
move through the CWA.
The main story this upcoming week will be the increasing
temperatures as the ridge to our west begins to shift into the Upper
Midwest. Both high and low temps will be slowly increasing through
the workweek, likely hitting their zenith around midweek. Looking at
percentiles from the NBM, conditions will be varying from very warm
to hot depending on location. In DLH for example, the 25th
percentile of the NBM is showing a high on Thursday of 84 degrees,
while the 75th percentile shows 92. For Hinckley, conditions will be
even warmer, with the NBM 25th percentile showing a high temp of 90
on Wednesday! These temps will also be accompanied by dewpoints
increasing into the upper 60s, which will lead to hot and muggy
conditions this upcoming week. Global models suggest that these very
warm to hot temps may moderate somewhat late in the workweek.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 624 PM CDT Sat Jul 22 2023
Early evening TSRA are currently on the waning trend, and while
KBRD is still at risk of getting storms for the next hour or two,
the other terminals are unlikely to get any more storms this
evening. Skies should be VFR overnight with light north-northwest
winds. Fog may develop at KBRD, KHIB and KHYR due to todays
rainfall, and have included some FM groups for these lowered
visibilities, with IFR the most likely for now. Cumulus with
scattered storms are expected to develop once again Sunday
afternoon, and have included a VCTS for KHIB for now, though they
may also affect other NE MN terminals, but for now the activity
appears too scattered for much confidence.
&&
.MARINE...
Issued at 158 PM CDT Sat Jul 22 2023
Showers and thunderstorms will continue to be possible this
afternoon before coming to an end this evening. A few storms,
especially near the Twin Ports and Chequamegon Bay, may become
strong to severe. These strong to severe storms will be capable of
producing gusty winds in excess of 34 knots and hail up to 1" in
diameter. On and off showers and storms will be possible from Sunday
afternoon into Monday. Winds will have a westerly component today
into Sunday morning. A wind shift to the northeast will likely occur
Sunday night into Monday, except along the North Shore from Taconite
Harbor to Grand Portage where winds will be from the southeast.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 58 81 57 78 / 10 20 40 20
INL 56 79 54 81 / 10 20 30 20
BRD 58 85 60 87 / 10 10 30 10
HYR 54 83 57 85 / 20 10 20 30
ASX 57 83 57 80 / 20 10 30 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
DISCUSSION...Unruh
AVIATION...LE
MARINE...Unruh
Area Forecast Discussion
National Weather Service Des Moines IA
1048 PM CDT Sat Jul 22 2023
...Updated for the 06z Aviation Discussion...
.DISCUSSION.../Tonight through Saturday/
Issued at 215 PM CDT Sat Jul 22 2023
Key Messages:
- Few strong storms possible yet this afternoon and early evening.
Best chance north.
- HEAT. Hottest air mass of the season inbound with triple digit
high temps in play mid-week.
- Pattern is favorable for periodic thunderstorm chances; even
during the morning hours. Individual disturbances difficult to
time, reducing confidence. Best chance still looks to be Monday
and Friday.
Discussion:
Northwest flow persists this afternoon with satellite pix showing IA
caught between shortwave troughs. The first that caused a few
morning showers has departed; while the next upstream trough seen
dropping southeast thru MN. The latter of which will be the focus
for isolated to scattered storms yet this afternoon and early
evening. SBCAPEs are progd around 1500 j/kg; along with bulk
shear increasing to around 30 knots, which will be sufficient for
a few storms to become strong or locally severe. This aligns with
SPCs Marginal risk. If storms do become organized, dry sub-cloud
layer points to gusty winds as the primary threat. Upstream
shortwave arrives to IA stateline by around 4P, which should be
convective initiation timing and put best opportunity of organized
convection across N Iowa. Models prog these storms dropping south
thru the evening before dissipating. A few CAMs initiate a few
storms earlier across central/southern Iowa in an area of weak
nebulous sfc convergence. In fact, a few weak showers have
already developed in this vicinity this afternoon.
Sunday looks dry as northwest flow persists. Models prog another
shortwave; however it`s weaker with less moisture to work with
compared to today`s. Clouds should accompany it though; which may
help cut a degree or two off high temps. Speaking of high temps,
the daily warm-up begins on Sunday, approaching 90 in spots. There
also is an outside chance for a rogue shower/storm; but
confidence isn`t high enough in occurrence to include for now.
Better chances for shower/storms arrive late Sunday night and into
Monday; as ridge begins to build east increasing WAA across the
midwest.
The heat begins to ramp up on Monday, peaking most likely in the
upper 90s for Wednesday and Thursday as the upper high builds
towards Iowa. Fortunately dew points in the upper 60s helps mitigate
the heat index impact. Even so, heat indices of 100-105F are
expected Wed-Thu. Those with plans outdoors this week should take
precautions including finding shade, avoiding peak afternoon
heat, and drinking plenty of water.
Additionally, this pattern is favorable for daytime convection being
sustained thru the overnight effectively "ridge riding" before
dropping southeast during the morning hours. Timing and location
of any thunderstorm complexes will depend on how far east the
upper high is able to build coupled with the placement of upstream
convection. Confidence too low to include in the Tue-Thu forecast
at the moment; but would not be surprised if storms chances have
to be added eventually sometime during this stretch. The ridge
flattens late in the week, allowing a cold front to slide south
and bringing the best shot of more widespread rain along with a
return to more seasonal temperatures.
&&
.AVIATION.../For the 06Z TAFS through 06Z Sunday night/
Issued at 1048 PM CDT Sat Jul 22 2023
Scattered storms weakening east of our area. Nighttime
microphysics showing cloud cooling near the I35 corridor. HRRR and
other CAMS light up an area of weak convection tracking south from
FOD to DSM around 06-12z. Coverage may be widely scattered,
similar to around 12z Sat (earlier today). Will cover with VCSH
for now, and let overnight crew update short term trends as
needed. Otherwise, expect VFR conditions with ambient wind less
than 12kt. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Hahn
AVIATION...REV
Area Forecast Discussion
National Weather Service Grand Forks ND
1013 PM CDT Sat Jul 22 2023
.UPDATE...
Issued at 1005 PM CDT Sat Jul 22 2023
Same sentiments in the previous update applies in this update
regarding smoke.
Some hi res guidance hints at some fog developing overnight into
early morning in portions of west-central Minnesota and into the
Red River Valley. Some sites in central Minnesota show vsby
reductions, which may be a hint that fog may be starting to
develop. Opting to watch observation trends before including in
the forecast.
Regarding Sunday`s conditional chance for isolated thunderstorms,
of which may be severe, 00 UTC CAMs continue to disagree in
placement and evolution of subtle mid level ways as well as
surface boundaries. Thus confidence in whether sustained
updrafts/storms within the weakly forced and capped environment
remains low.
UPDATE Issued at 648 PM CDT Sat Jul 22 2023
Smoke is intruding the northern Valley and northwest Minnesota as
observed through surface observations and webcams. Added smoke to
the grids to account for this. Guidance offered by HRRR and RAP
suggest this surface smoke will linger in these areas through the
evening, tonight, and into Sunday. Smoke aloft across the entire
area will also lingering through tonight into Sunday, perhaps
thinning near central North Dakota as the day progresses Sunday.
This may have a hand in limiting instability potential regarding
tomorrow`s conditional chance for thunderstorms, although holds
low confidence without knowing exactly how much thinning of smoke
may occur in our area.
Otherwise, isolated showers and thunderstorms near north-central
MN are diminishing with the loss of daytime heating (partly helped
by thick smoke aloft), as well as loss of forcing for ascent.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 317 PM CDT Sat Jul 22 2023
A weak cold front moved through the area today with northwesterly
winds in place and a few isolated storms that formed along the
boundary in the far east. This activity is expected to quickly move
east as the front pushes east of the area into the evening hours.
Upper level smoke will continue to stream across much of the area
with northwest flow pattern in place aloft through Sunday. Another
weak wave will drop southeastward through the region Sunday into
Sunday night. Return flow will set up quickly late tonight with WAA
nosing into the region ahead of the weak shortwave. This could allow
some light showers/isolated storms to develop into the
north/northwest toward sunrise into Sunday morning. If lift is
weaker/less moisture increasing cloud cover is more likely with less
chances for precipitation. Conditional threat for additional
shower/storm threat into Sunday afternoon/evening as well with the
continued reinforcing area of waa in place and thermal gradient
situated across the central/eastern portion of the area. Greater
likelihood of a general area of activity in the north/northeast
through the evening, however some CAMS develop more discrete
activity across the west/south where greater instability and
stronger deep layer shear around 30-40kt will be present.
Therefore there is a chance for a potentially strong storm if
activity develops further west.
.LONG TERM...(Monday through Saturday)
Issued at 317 PM CDT Sat Jul 22 2023
The northwest flow pattern continues across the area into Monday
with another round of weak impulses aloft dropping through the
area. Therefore the chance for another round of scattered showers
and a few storms will possible through the day. Western US upper
ridge begins to build eastward into Tuesday and Wednesday with the
thermal ridge aloft nosing into the region. This will build in
much warmer temperatures for mid week as H85 temperatures push
into the 20s celsius. A near continuous flow of weak energy aloft
through the top of the ridge to move through southern
Canada/portions of the forecast area through mid-week. This will
keep chances for scattered storm development in place through
much of the week, with activity expected to develop along the edge
of the thermal ridge that remains entrenched across the region
through the week. The upper ridge to flatten and begin to break
down by the end of the week into the weekend with a return to
cooler, more seasonal conditions Friday. A cold front associated
with a stronger upper level trough moving through the prairie
provinces of Canada will keep the cooler conditions in place into
next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 648 PM CDT Sat Jul 22 2023
VFR conditions are forecast thought the TAF period. However,
thick smoke aloft is forecast through the TAF period.
Additionally, surface smoke reducing vsby to around 4SM is
forecast within the northern Red River Valley into northwest
Minnesota through the TAF period. This includes vsby impacts to
KGFK, KTVF, and possibly KBJI after 12 UTC Sunday. There is a low
to medium chance this surface smoke may reach further south than
forecast.
Otherwise, light winds under 10 kt are expected. There is a
low chance in showers and thunderstorms into the area after 15
UTC Sunday.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...CJ
SHORT TERM...MJB
LONG TERM...MJB
AVIATION...CJ
Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
1009 PM EDT Sat Jul 22 2023
...New UPDATE...
.UPDATE...
Issued at 958 PM EDT Sat Jul 22 2023
We continue to have a few stray showers out there, mainly north
of I-40, this evening. The last few HRRR runs seem to be handling
this ok so I trended PoPs through the overnight hours in that
direction. There is a weak impulse that is swinging east through
the TN/KY border and will not clear to the east until roughly
daybreak. The PoPs from the last HRRR run subsequently keep some
slight chances in the northern TN and southwest Virginia mountains
through the overnight hours. Doubtul there will be more than 2-3
showers through the night but believe leaving some slight chances
in seems warranted. Otherwise, no real changes seem necessary.
&&
.SHORT TERM...
(This evening through Sunday)
Issued at 258 PM EDT Sat Jul 22 2023
General 500 MB troughing over the area, but expecting mainly
diurnal activity this evening and again Sunday. I think the main
convection Sunday is over the mountains, Plateau, and SW VA. But
we are carrying chance-type POPs over the northern Valley also.
That might be a tad aggressive, but an approaching 500 mb trough
axis might make it reasonable. (Northwest flow is always tricky.)
Temperatures around normal values for Sunday.
&&
.LONG TERM...
(Sunday night through next Saturday)
Issued at 258 PM EDT Sat Jul 22 2023
Key Messages:
1. Ridging builds back in across the Tennessee Valley next week with
a trend of increasing temperatures and dew point values.
2. Isolated chances for a shower or thunderstorm next week primarily
across higher terrain of the mountains and plateau.
Discussion:
With the ever so persistent high pressure dome out west and longwave
troughing east of the Mississippi, the pattern aloft will begin to
transition. The trough will lift north and ridging will build in
from the west. The persistent northwesterly to westerly flow we have
been in will become weak as this transition occurs around late
Monday into Tuesday. With high pressure strengthening at the surface
and weak flow aloft, chances of showers and thunderstorms will
mostly be limited during peak heating hours. Chances will be best
over higher terrain due to differential heating along the terrain. A
gradual increase in low-level moisture will occur as well, as
surface winds become southwesterly in the afternoon.
With ridging aloft and subsidence in mind, we can expect
temperatures as well as dew point values to increase each day into
the period. Some Valley locations will push into the 70 degree
reading for dew points beginning mid-week. If the aforementioned
holds, heat indices will be in the 90s to near 100.
Although far out in the forecast, models highlight a possible
shortwave trough that will ride over the top of the ridge and thus
approach us from the northwest. This may bring better chances for
showers and thunderstorms for non higher elevation spots. Will see
how this unfolds with future model runs.
&&
.AVIATION...
(00Z TAFS)
Issued at 742 PM EDT Sat Jul 22 2023
Will not carry any mention of convection in the 00z TAF package.
The diurnal window for storms is rapidly closing this afternoon,
and while coverage should be better tomorrow, they should mostly
occur very late in the period. Otherwise, the only flight category
concern will be the possibility of some fog and low clouds at KTYS
and KTRI. Believe lack of rain today vs yesterday will favor
slight VSBY restrictions versus low clouds so have gone that
route.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 67 85 66 89 / 10 0 0 0
Knoxville McGhee Tyson Airport, TN 66 84 64 86 / 10 20 0 10
Oak Ridge, TN 66 83 64 86 / 10 20 0 10
Tri Cities Airport, TN 62 82 62 84 / 20 50 10 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...CD
LONG TERM....KS
AVIATION...CD
Area Forecast Discussion
National Weather Service Phoenix AZ
513 PM MST Sat Jul 22 2023
.UPDATE...Updated 00Z Aviation Discussion.
&&
.SYNOPSIS...
Excessive Heat will continue for the next several days as the
Monsoon High remains entrenched across the Desert Southwest. The
threat of isolated to scattered afternoon and evening
thunderstorms will persist through the week, particularly across
the higher terrain east of Phoenix.
&&
.DISCUSSION...
Latest mesoanalysis depicts the center of the Monsoon High across
southern Utah. Consequently, there is a weak easterly component
to the steering flow across Arizona. Despite the positive height
anomalies, 500 mb temperatures are relatively cool near -6 to -7
deg C, which is yielding steep mid-level lapse rates. Latest
observations indicate warmer and drier conditions than at this
time yesterday. Dewpoints generally in the lower 50s portends
widespread CIN of 100+ J/kg this afternoon and evening with only a
slight chance of storms in the lower deserts. Meanwhile, Sky
Harbor Airport has already reached 115+ degrees this afternoon,
making it the 23rd consecutive day with highs of at least 110
degrees.
Latest HREF has trended somewhat quieter for this evening and
conceptually that makes sense. Although most locations won’t see
any rainfall, textbook inverted-V soundings point to the potential
for strong downburst winds with any storms that may develop,
particularly across the higher terrain east of Phoenix, including
the foothills. However, if downbursts organize into a discrete
outflow boundary, this may be sufficient to overcome the
convective inhibition in the Valley, resulting in isolated
convection.
Considering that only the HRRR indicates activity this
evening across the lower deserts, PoPs were lowered below the NBM
to around 15 percent in Phoenix, but up to 25 near Casa Grande.
Further east near Globe, PoPs were lowered to around 30 percent
near Globe. Later this evening, models continue to suggest a
larger outflow boundary will propagate northwestward from southern
Arizona. There is a 30-50 percent chance of wind gusts reaching
35 mph across Pinal and southern Maricopa Counties, which will be
sufficient to generate areas of blowing dust and reduced
visibilities, and a Blowing Dust Advisory remains in effect for
these areas.
&&
.PREVIOUS DISCUSSION...
Looking forward to Sunday, convective activity/coverage is
expected to peak, as the sub-tropical ridge centers over the four
corners region, resulting in a more favorable monsoon pattern
with southeasterly flow over the region. Larger areas of
instability due to the increased moisture around 1000 J/kg
according to the latest HREF will lead to favorable thunderstorm
development across the higher terrain, and then eventually into
the lower deserts where there is generally a 30-40% chance across
the metro and 20-30% chance spreading westward into southwestern
Arizona by tomorrow evening. Thus, Sunday may be the day that the
dry streak across the majority of the metro will come to an end.
Strong outflows will be a factor again tomorrow, with
probabilities of significant wind gusts (35 mph or greater) higher
across the region due to the anticipated greater coverage of
thunderstorm activity.
After Sunday, global models suggest the H5 anticyclone will
strengthen a bit again, but the abnormally high heights will be to
our east. This should put Arizona roughly in the moist southerly
return flow on the upstream side of the ridge. Temperatures will
continue to be hot with persistent chances for mountains
showers/storms. Mitigating factors though would include slightly
increasing mid-level temperatures and a dry southwesterly flow
over California mixing in from the west.
&&
.AVIATION...Updated at 0009Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Gusty outflow winds are expected this evening and tonight. Initial
outflows are favored to arrive from the northeast or east, mainly
after 0100Z. Another outflow is expected to move up from the south
later tonight, after 7Z. The outflows will be capable of producing
wind gusts in excess of 30 kts (30% chance), which may also lead
to localized BLDU or HZ. There are also low chances (10-15%) for
VCSH/VCTS this evening/tonight, mainly between 1-9Z. By 12Z, light
east winds are expected and will prevail through midday Sunday,
with periods of variability before shifting west around 19-21Z.
FEW-SCT cumulus and high debris clouds are expected through much
of the period, with bases aoa 10-12K ft.
Southeast California/Southwest Arizona including KIPL and KBLH:
The main aviation concern will be a robust outflow moving over the
region early tomorrow morning. Winds this afternoon at IPL will be
light out of the SE, while BLH will see winds favor a more S`rly
direction, with occasional 20-25 kts gusts. A strong outflow
originating from afternoon and evening convection over southern
Arizona and northern Mexico is expected to push through the region
between 08-11Z, generating windy conditions with gusts upwards to
35 kts. There is also a low chance (15%) for isolated high based
showers/storms or virga, mainly near KIPL, between 14-19Z Sunday.
FEW-SCT mid-level and SCT high-level clouds will prevail during
the period.
&&
.FIRE WEATHER...
Thunderstorm activity is expected to become more widespread across
the region over the next couple of days. The most widespread
impact from regional storm activity through tomorrow will be
strong gusty winds. Areas of wetting rains remain limited today
but increase to 20-30% tomorrow afternoon and evening across
south-central AZ. Well above normal temperatures will continue
through early next week despite the increased monsoonal
thunderstorm activity. RH`s will trend higher due to the influx of
moisture, with overnight recoveries trending to fair through early
next week. Apart from thunderstorm influences, winds will
continue to favor warm season patterns with long lived upvalley
winds in the afternoon and evenings with shorter lived downvalley
patterns in the late night and morning hours.
&&
.CLIMATE...
Record High Temperatures:
PHOENIX YUMA EL CENTRO
July 22 116 (2006) 116 (2006) 119 (2006)
July 23 115 (2018) 117 (2014) 118 (2018)
July 24 116 (2018) 118 (2018) 121 (2018)
Active Streaks:
PHOENIX
1. Consecutive days of high temperatures 110F or greater: longest
on record at 23 days
2. Consecutive days of high temperatures 115F or greater: tied longest
on record at 6 days
3. Consecutive days of low temperatures 90F or greater: longest on
record at 12 days
4. Consecutive days of zero precipitation: 6th longest on record at
121 days
YUMA
1. Consecutive days of low temperatures 85F or greater: 6th longest on
record at 12 days
July 2023 Notes:
PHOENIX
1. Current average temperature of 102.5F is on pace for the hottest month
on record (second hottest month was August of 2020 at 99.1F)
2. All-time warmest low temperature of 97F set on July 19th
3. Daily record high temperatures tied or broke the previous record
for seven days (July 13th, 14th, 15th, 17th, 18th, 19th, and 20th)
YUMA
1. Daily record high temperatures tied or broke the previous record for one
day (July 19th)
EL CENTRO
1. Daily record high temperatures tied or broke the previous record for three
days (July 15th, 18th, and 20th)
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST this evening for
AZZ530>533-535-536-545-547-552-556-560>562.
Excessive Heat Warning until 8 PM MST Tuesday for AZZ534-537>544-
546-548>551-553>555-559.
Heat Advisory until 8 PM MST this evening for AZZ557-558-563.
Blowing Dust Advisory until 11 PM MST this evening for
AZZ550>555-559.
CA...Excessive Heat Warning until 8 PM PDT this evening for
CAZ560>570.
&&
$$
DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Young/Iniguez
AVIATION...Benedict/RW
FIRE WEATHER...Young
CLIMATE...Young
Area Forecast Discussion
National Weather Service Shreveport LA
917 PM CDT Sat Jul 22 2023
...New UPDATE...
.UPDATE...
Issued at 914 PM CDT Sat Jul 22 2023
Update has been sent to pull back pops to slight chance variety
for our far southern zones for the remainder of the night. Frontal
boundary has shifted south of our region with remaining convection
across our far southeast zones in the wake of the sfc frontal
boundary. This convection should continue to lose coverage and
intensity as we go through the remainder of the night. Concerning
temperatures, we were not cooling quite as quickly as our diurnal
curve suggested to did some hourly forecast temperature and
dewpoint manipulation to mimic current trends. Did however leave
forecast low temperatures as they were.
No additional changes necessary.
13
&&
.SHORT TERM...
(This evening through Sunday Night)
Issued at 255 PM CDT Sat Jul 22 2023
A weak surface cold front has finally moved south of the forecast
area. However, ascent from an upper trough axis diving southeast
across the the ArkLaTex has helped to initiate scattered
convection south of the Interstate 20 corridor. The showers and
thunderstorms are forming in the vicinity of an elevated frontal
boundary and where 3000-4000 J/kg of SBCAPE has built. The
convection has so far remained somewhat spotty and somewhat
short-lived with quick-developing outflow boundaries. Temperatures
have soared into the upper 90s to lower 100s in Deep East Texas
yielding surface dewpoint depressions of 30 to 40 degrees F. In
addition, mesoanalysis suggests the presence DCAPE on the order of
1000 J/kg in our southern zones. Therefore, severe weather in the
form of damaging winds and downbursts cannot be completely ruled
out through early this evening if these individual cells can
congeal and form some persistent, longer-lived clusters. The
showers and thunderstorms will very slowly move south this evening
and should largely exit the area around midnight tonight. No
other precipitation is expected for the remainder of the short-
term period.
Clouds have also been relatively persistent behind the front, but
skies should gradually clear from north to south this evening and
overnight. Quiet conditions are expected for Saturday. North of
I-20, temperatures should be a few degrees warmer than today under
the abundant sunshine. However, south of I-20, temperatures should
be a few degrees cooler compared to their hot temperatures today.
Daytime highs will generally range from near 90 degrees F in
Southeast Oklahoma and Southwest Arkansas to the mid 90s in Deep
East Texas and the Toledo Bend Country. The cooler air and lower
dewpoints in the wake of the front should finally keep heat
indices below advisory criteria, so no heat headlines are
currently anticipated for Sunday.
CN
&&
.LONG TERM...
(Monday through next Friday)
Issued at 255 PM CDT Sat Jul 22 2023
The new work week is looking rather late summer like with little to
no rainfall on the horizon until next weekend with another weak
frontal boundary. Until then, the upper level heat ridge will expand
back over our region as the deep trough lifts away. The entire
country will be governed by two deep lows on the Pacific NW coast
and a Hudson Bay low over Canada.
The core of the upper high is modeled to begin the week at 597dam,
on both the GFS and ECMWF centered over NM/CO. Early in the week the
core will be large and circular, but with time the Pacific NW low
will climb over the ridge and elongate the feature. The core will
hold position over NM building to 600dam by Tuesday afternoon. Our
heights aloft will climb a bit as the upper level ridge is stretched
W and E. By late in the work week, as the 597dam core retrogrades a
bit into AZ/NM.
The Pacific NW low will translate across Canada and fill and merge
into the semi-permanent Hudson Bay trough and actually allow a weak
1016mb sfc high to drop down over the southern plains. This will be
our next best chance for rainfall aside from southern tier echoes of
afternoon convection along the washing out frontal boundary. And
just like this weekend`s frontal boundary, rainfall will be hard to
come by in our area next weekend. The best chance may be overnight
Friday into early Saturday as the low level jet feeds Gulf moisture
over the front. Suffice it to say, the Drought Monitor will become
part of our discussions this week along with more heat products
likely this week with lows back in the mid to upper 70s and highs in
the mid to upper 90s with a few triples here and there. /24/
&&
.AVIATION...
(00Z TAFS)
Issued at 426 PM CDT Sat Jul 22 2023
The only trouble spot for this TAF period is the LFK terminal
where VCTS will continue to be an issue at least for the first
3-4 hours. Beyond convection, cannot rule out some residual MVFR
ceilings but those should dissipate by sunrise or shortly
thereafter. Otherwise, a scattered cu field should continue to
scatter out the closer we get to midnight with VFR conditions
prevailing with the exception possibly the LFK terminal as
referenced above. NBM and GFS are hinting at some post-frontal fog
late tonight through 7-8am Sunday Morning but the HRRR and NAM
output keeps fog out of our airspace. Did not include any VSBY
restrictions with this TAF package but will anxiously look for a
new 00z model suite for possible VSBY restrictions included in
the 06z TAF package.
13
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 73 94 74 98 / 0 0 0 0
MLU 69 92 70 95 / 0 0 0 0
DEQ 67 92 69 93 / 0 0 0 0
TXK 70 93 71 95 / 0 0 0 0
ELD 67 89 69 92 / 0 0 0 0
TYR 72 96 74 99 / 0 0 0 0
GGG 71 94 72 98 / 0 0 0 0
LFK 75 97 74 99 / 20 0 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
SHORT TERM...09
LONG TERM....24
AVIATION...13
Area Forecast Discussion
National Weather Service Las Vegas NV
817 PM PDT Sat Jul 22 2023
.SYNOPSIS...A strong ridge of high pressure will be over the Four
Corners Region on Sunday resulting in more favorable conditions
for monsoonal moisture through early next week. This will not only
bring an increasing chance of thunderstorms but will provide a
break from the excessive heat. Troughing to our north later in
the week will suppress the ridge and result in drier conditions.
&&
.UPDATE...Convective activity has largely dissipated across the
area, with only a few showers/virga lingering in Lincoln County.
These should die off quickly in the next hour or so as the sun sets.
Showers and storms will be possible again tomorrow, expanding
farther west to the I-15 corridor and maybe even the Sierra crest.
Gusty outflow winds, lightning, and brief downpours are the main
concerns. Monday looks to be even more active, with the latest NBM
giving widespread 20-40% PoPs over the eastern half of the CWA.
Precipitation potential wanes slightly on Tuesday, but more notably
on Wednesday as southwesterly flow scours out the moisture.
Temperatures remain above normal through the week.
&&
.DISCUSSION...Sunday through next Saturday.
There is good ensemble agreement that high pressure will shift
east of the area on Sunday becoming centered over the Four Corners
region. This sets up a favorable flow for advecting monsoonal
moisture into our area from deeper moisture pooled to our south
and east. The pattern generally holds through Tuesday although
the high center is forecast to shift to the southeast over central
New Mexico. Monsoon moisture remains in place with storm chances
increasing and storm coverage expanding Monday afternoon and
evening. Scattered storms continue across Mohave County Tuesday
afternoon with storm further west, more isolated.
Although we are expecting a small decrease in temperatures on
Sunday with the increasing moisture, temperatures are expected to
remain well above normal with excessively hot conditions
continuing. The coverage area for major to extreme heat impacts
is forecast to shrink, especially across our southern areas,
however heat-related impacts will continue and the Excessive Heat
Warning remains in place for Sunday. There is a sufficient drop in
forecast temperatures on Monday to lower widespread heat risk into
the moderate category allowing thus ending the need for heat
related headlines.
Transitioning from heat to monsoon thunderstorms, the GEFS
ensemble mean resolves a weak inverted feature over northern
Mexico tonight turning it northward and bringing across our
western areas on Sunday. Not only does this feature bring a weak
surge of monsoonal moisture northward, it could also act as a
source of lift for enhanced updrafts and potentially isolated
stronger storms Sunday afternoon. Taking a look at hi-resolution
model output, the HRRR composite reflectivity plots bring an
initial round of enhanced reflectivity (showers or storms) to San
Bernardino County Sunday morning. As the inverted feature lifts
north, storm coverage is forecast to expand across the Sierra and
mountains of Clark and Lincoln counties. The HRRR also has storms
forming across northern Mohave County in the afternoon mainly due
to increasing instability from daytime heating. Another round of
more organized convection is forecast by the HRRR to move into
southern Mohave and San Bernardino counties Sunday evening and
then dissipates before reaching Clark County overnight Sunday into
Monday.
Low pressure troughing develops across the northern Great Basin
and northern Rockies Tuesday through Thursday. This acts to
suppress the ridge and scour out some of the moisture in our
area on Wednesday although a chance of thunderstorms continue over
mainly Mohave County Wednesday afternoon. The rest of the area is
expected to be mainly dry with decreasing moisture and
instability.
All areas are dry Thursday through Saturday with temperatures 3-5
degrees above normal.
&&
.AVIATION...For Harry Reid...Light east/northeast winds this morning
to shift to the south and southwest this afternoon through evening.
Wind speeds to remain 10 knots or less through around 20z.
Thereafter, as winds shift to the southeast and eventually
southwest, speeds of 10-15 knots can be expected with gusts near 20
knots. One caveat will be a very low chance of enhanced winds from
storms well east of the terminal. Should this materialize, it would
happen in the 01z to 05z timeframe with gusty east/southeast winds.
However, the probability of this is quite low, perhaps 20 percent or
less. Scattered clouds at 15-20kft will persist through the period.
Hot temperatures will maintain density altitude of around 6kft.
For the rest of southern Nevada, northwest Arizona and southeast
California...Isolated showers and thunderstorms look to develop well
east of terminals this afternoon into the evening. With high
pressure in control, winds will generally remain diurnal and driven
by the higher terrain. Wind speeds to generally remain 10-15 knots
or less with the exception of KBIH/KDAG and terminals along the
Colorado River Valley, where winds may occasionally gust 20-25 knots
from 21z-03z. Winds will generally decrease from 04z-09z, becoming
light overnight.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Woods
DISCUSSION...Salmen
AVIATION...Austin
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