Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/24/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
926 PM CDT Sun Jul 23 2023
.UPDATE...
Issued at 923 PM CDT Sun Jul 23 2023
Forecast is doing fine this evening. Only changes were to pops
over eastern CWA where latest runs of the HRRR have been
highlighting late night llj/waa storms forming, especially over
southeast SD. Temperatures look fine.
&&
.SHORT TERM...(This Evening through Monday Night)
Issued at 323 PM CDT Sun Jul 23 2023
A couple embedded weak disturbances within the northwest flow aloft
continue to bring isolated showers/thundershowers to parts of the
region. This activity should wane as we head into the evening hours,
with some potential for redevelopment late tonight as a weak surface
low drifts southward across central SD. Not much of a low-level jet
tonight, but about 30 knots does develop into southeast SD, which is
where CAMs/paintball output try to pinpoint "best" chances for
precip. Forecast maintains 20/30 percent chances across eastern
areas late tonight.
Forecast remains dry on Monday as upper level ridging nudges
eastward, with increasing heights and warming aloft strengthening
over the CWA. Forecast highs have come down a few degrees compared
to the last forecast cycle, but should still see highs into the 90s
along and west of the James River, and even close to 100 over the
southwest CWA. Heat indices don`t appear to be an issue quite yet on
Monday, so no headlines at this time.
.LONG TERM...(Tuesday through Sunday)
Issued at 323 PM CDT Sun Jul 23 2023
The long term portion of the forecast begins on Tuesday with an
upper level ridge moving into the region from the west, with
southerly flow in the lower levels. While an EML will move into the
CWA on Tuesday, some models still suggest convection during the
afternoon and overnight hours. There appears to be two locations for
convective development. The first is over western ND where the EML
is weaker, and there is some upper level support from trough off to
the west. The ND storms may remain north of this CWA. A lee of the
Black Hills surface low may weaken the EML over south central SD for
afternoon thunderstorms. Convection would impact at least the
southwest portion of the CWA Tuesday afternoon and evening. With a
quarter of an inch of QPF from WPC, along with support from the
ECMWF, have added a schc pop for the western CWA starting at 21Z
Tuesday. Thunderstorms should exit the region by Wednesday with hot
and dry conditions expected. Wednesday should be the warmest day of
the week with highs reaching the 90s to 100 degrees for most
locations. Heat indices should reach 100 to 105 degrees.
A gradual cooling trend develops on Thursday as more than one area
of low pressure and associated cold fronts slides across the region.
Each frontal boundary will bring the potential for showers and
thunderstorms, and slightly cooler temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 615 PM CDT Sun Jul 23 2023
Terminals KABR,KATY,KPIR,KMBG
Expect VFR skies/vsbys through tonight.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TDK
SHORT TERM...TMT
LONG TERM...SD
AVIATION...TDK
Area Forecast Discussion
National Weather Service Amarillo TX
655 PM CDT Sun Jul 23 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Monday night)
Issued at 240 PM CDT Sun Jul 23 2023
The 500mb high pressure center is expected to continue its
progression further east this afternoon with most models expecting
the center to hold over New Mexico. This shift has already begun
to dry us out for the day with most sensors reporting that
dewpoint temperatures are declining under 60 degrees in the
western half of the Panhandles. Expect these drying conditions to
persist into to tomorrow as well with most models seeing the high
strengthen over the next few days. With weather turning back to
the drier side, temperature will now become the main focus for
today and tomorrow. Currently most model are reporting 850mb
temperatures to rise today to around 30 to 31 degrees Celsius
today, which roughly calculates to about 99 to 98 degrees
Fahrenheit for high temperatures in the city of Amarillo. Given
this potential high temperature for Amarillo, triple digits
temperatures are not out the question for today with places like
the Palo Duro Canyon looking at a 50% chance of exceeding 100
degrees. These warmer temperatures continue to be something the
NBM is struggling to pick up on with runs continuously 3 to 4
degrees cooler than the outcome, so have decided to use the 90
percentile version of the NBM to adjust for the cooler bias.
Heading into Monday, the warming trend is expected to continue as
more locations around the Panhandle reach into the triple digits.
In our hotter location, heat related products are not out of the
question, with the Palo Duro Canyon already under a Heat Advisory
tomorrow afternoon. The only thing that may hold the warm
temperatures at bay are the early evening storms that latest HRRR
and NAM nest runs expect to form off the Rockies. However, latest
guidance is only giving a 10% chance at best for those storms to
reach the western half of the Panhandles, which make sense given
models are expecting weak steering flow for the day.
Scoleri
&&
.LONG TERM ...
(Tuesday through next Saturday)
Issued at 240 PM CDT Sun Jul 23 2023
Hot and dry weather looks to continue for Tuesday as the 500mb
pressure high pressure center strengthens further with some models
runs now seeing 500mb heights peak at 600dm that afternoon.
Latest guidance is still trending for Tuesday to be the hottest
day of the week with multiple locations warming into the the
triple digits that afternoon and evening. However, the NBM is
still struggling with it placing most locations a full 3 to 4
degrees cooler than what other models and 850mb temperatures
suggest. Regardless, heat related products will be likely in
places like the Palo Duro Canyon where temperatures could reach
108 degrees at the floor of the canyon by that evening. The only
thing that might aid in seeing slightly cooler temperatures is the
breezy southwesterly winds that will be present for most of the
day.
Heading into the mid-week, model agreement do expect the high to
weaken slightly, but still hold its position over New Mexico. What
will be interesting to watch, however, are the potential
disturbances that are still expected to move across the high clear
through the end of the week. In previous models runs, the upper-
level flow was much better and allow these disturbance to follow
the typical pattern of having storms form off the Rockies and then
move into the Panhandles. However with the high expected to stay
put, that flow has become much weaker which, in turn, has resulted
in diminished chances of storms each day. Currently, latest
guidance is now placing best chances for storms along the
Texas/New Mexico border, though they are only a 17% chance at
best. Should this new trend hold, then it is not out of the realm
of possibility for the Panhandles to see triple digit temperatures
clear into the weekend.
Scoleri
&&
.AVIATION...
(00Z TAFS)
Issued at 636 PM CDT Sun Jul 23 2023
TAFs are VFR at all sites for this period. Winds will shift from
south to southwest tomorrow morning, and speeds will be between
10-15kts. Occasional wind gusts around 20kts may be had at all
sites tomorrow afternoon, but their infrequency has led us to
leave them unmentioned at this time. Mostly clear skies are
expected tomorrow. Ceilings will remain at or above 10,000ft.
Rangel
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 72 104 75 104 / 0 0 0 0
Beaver OK 72 101 75 102 / 0 0 0 0
Boise City OK 68 100 68 101 / 0 0 10 0
Borger TX 75 106 78 107 / 0 0 0 0
Boys Ranch TX 72 107 74 107 / 0 0 0 0
Canyon TX 71 103 74 104 / 0 0 0 0
Clarendon TX 73 103 76 103 / 0 0 0 0
Dalhart TX 67 101 68 103 / 0 0 10 0
Guymon OK 70 101 71 103 / 0 0 0 0
Hereford TX 70 104 73 105 / 0 0 0 0
Lipscomb TX 72 102 75 104 / 0 0 0 0
Pampa TX 73 101 76 101 / 0 0 0 0
Shamrock TX 70 102 73 103 / 0 0 0 0
Wellington TX 70 104 74 105 / 0 0 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 1 PM to 9 PM CDT Monday for TXZ317.
OK...None.
&&
$$
SHORT TERM...11
LONG TERM....11
AVIATION...55
Area Forecast Discussion
National Weather Service La Crosse WI
1042 PM CDT Sun Jul 23 2023
.DISCUSSION...(This evening through Sunday)
Issued at 238 PM CDT Sun Jul 23 2023
Key Messages:
- Building heat is the main story of the week with Wednesday and
Thursday looking the hottest. Humidity wont be unusual which
means heat index values of ~5F higher than temperatures.
Peaking 98-103F on Thursday afternoon.
- Smoke to continue to influence the area through Monday. North
and east of La Crosse could see AQIs in the 100-150 range.
- Some morning valley fog and storm chances Monday. A strong
storm could be possible in the afternoon mainly in WI north and
east of La Crosse.
Smoke to Continue Its Influence
Current observations across northern MN show AQIs of 100-150 in
smoke with surface visibility in the 3-6 mile range. At least
through Monday, smoke will again influence the area with higher PM
2.5 densities expected north and east of La Crosse per HRRR smoke as
they sweep in from northern MN. AQI forecasts would suggest
values of 100 to 150 would be possible, with hazy skies in smoke
aloft elsewhere.
Monday Morning Valley Fog Being Monitored
There is some signal for valley fog Monday morning with the area
dewpoints not mixing much today with weak wind flow. Seems much of
the night skies will be clean for radiational cooling and winds
through 7-10kft are less than 10kts. Provided upstream shortwave
troughs over ND and near KINL dont bring too much cloud in,
valley fog may be possible. Will need to monitor overnight. The WI
river valley will fog again irregardless.
Monday Thunderstorm Chances
The area will be influenced by weak shortwave troughs in northwest
flow on Monday near and north of La Crosse...and another low
pressure area enhancing the low-level theta-e convergence in Iowa
later in the day. Forecast soundings show a largely uncapped
environment with ~1000 J/Kg of MLCAPE by Monday afternoon in
northcentral WI with weak warm advection in low-levels. The
capping does increase southwestward into northeast Iowa, but also
is a function of dewpoints. Seems with little mixing, low 60s
dewpoints are a reasonable value which would favor more of the Hi
Res ARW and NAMNest forecasts. These ignite some afternoon storms.
The HRRR latest extended run at 12Z mixes too aggressively again
with low 50s dewpoints. So, while there isnt much for a surface
convergence boundary, any troughs that can lift a bit would ignite
showers or storms Monday afternoon. Again, mainly north and east
of La Crosse in the less capped environment. There could be a bit
better wind shear in place with marginally supercell deep shear,
so storms might need to be watched in this area for marginally
higher organization for a large hail producing storm.
Heat Builds This Week with Impactful Heat in a Short Window
Large scale ridge building into the Great Lakes will bring heat to
the area starting Tuesday. Confidence remains lower than normal
for extreme heat probabilities when compared to a normal heat
wave. These events typically can have higher predictability. Part
of the issue is the GEFS continued hot bias in the low-levels and
to what degree is there signal in that 30% of the Grand Ensemble
of EC/Canadian/GEFS. For example, the GEFS probability of 100F+ at
KLSE Wed and Thu are 66 and 67%, respectively, while the
corresponding ECMWF EPS is 0 and 8%. The cooler EC members feeding
the NBM have kept it reasonable and will continue to be close to
that guidance vs. GEFS/GFS/GFS MOS. Wednesday and Thursday look
the hottest, with rain chances mainly to the south along the
slowly moving, northward warm front and moisture transport across
Iowa/northern IL. The river valleys along and south of I-90 will
see the highest temperatures this week. Dewpoints do not seem
oppressive, but more near normal ~70F. This produces heat index
values of about 5F above temperatures. Thus, Thursday`s peak heat
index values are 97-103F.
Clouds and precipitation will definitely play into the forecast
temperatures, especially after Thursday. Somewhere in the region it
appears there will be some probability of a preferred MCS "ridge
runner" storm track from NW->SE north of the warm front. Current
GEFS placement would be to the south along I-80, where as the
latest ECMWF ensemble runs suggest right through the area. The
latest GEFS has about 30% of the members suggesting a stronger
influence of the Hudsons Bay trough /highs=80s/ while the 00Z
ECWMF ensemble would hold at least a moderate (possibly strong)
ridge in place with mid 90s for highs into the weekend. So, the
large scale predictability is still quite low for late week due to
these differences. 30-50% rain chances are sprinkled through the
Thursday night to Sunday period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1042 PM CDT Sun Jul 23 2023
Main taf concern is fog development in river valleys overnight. With
clear skies and light winds...fog is expected to develop
overnight...mainly in river valleys. Confidence in fog to impact the
LSE taf site not as high as previous night and it appears the fog
may not be as widespread in the Mississippi River Valley. Will
continue with patchy fog and introduce a brief period of MVFR
condition at the LSE taf site. Weak shortwave troughs will track
over the Upper Great Lakes Region Monday. The higher chances for
any convection will be east and west of both RST/LSE taf sites and
the latest hi-resolution models develop the convection east/west
of the taf sites. Will continue with no showers/storms in either
tafs for Monday.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Baumgardt
AVIATION...DTJ
Area Forecast Discussion
National Weather Service Binghamton NY
954 PM EDT Sun Jul 23 2023
.SYNOPSIS...
High pressure is moving east of our region, opening the door for
increased warmth and moisture the next few days. Scattered
showers and thunderstorms can be expected Monday and perhaps
Tuesday, followed by hot and humid conditions during the second
half of the week. Our next better chance for thunderstorms will
be around Friday as a cold front moves into the region.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
950 PM Update...
Very minor adjustments to the forecast to account for some pop
up showers over Steuben county late this evening. Some of the
latest CAMs such as the 00z HRRR keep a pop up shower or two
around through the overnight; but confidence and coverage was
too low to carry anything but sub mentionable (< 15%) PoPs after
midnight and into the overnight at this time. Current temperatures
are falling back into the 60s and low 70s as expected. Overnight
lows are not forecast to be as cool as what we saw last night;
instead dipping into the mid-50s to low 60s tonight.
740 PM Update...
Just a few isolated lingering showers and t`storms...one over
far eastern Otsego county, one entering northern Seneca county
and a shower down in Pike county. Otherwise, visible satellite
shows clearing skies as daytime instability wanes. Expecting
mainly dry weather overnight, with areas of fog developing in
the typical river valley locations after midnight. Made some
minor adjustments to slightly increase PoPs and tweak
temperatures into Monday, but overall the near term forecast
remains on track.
240 PM Update...
Isolated weak storms will diminish late this afternoon, then
the main concern will be for scattered showers and thunderstorms
Monday which could contain localized downpours and gusty winds.
Diurnal heating, and exiting shortwave, were enough to get small
clusters of convective showers and isolated thunder going by
early afternoon. However, plenty of dry air exists in the
midlevels. With precipitable water values only around an inch or
so, coverage of convection will continue to be few and far
between; most locations will be dry today and even for those
locations that get a storm it will brief. Because of the amount
of dry air involved in the column, any cell will be capable of
promoting gusty cool pools, yet also will get entrained pretty
quickly once each convective cell gets above 15-20 kft. The RAP
model depicts downdraft convective available potential energy
(DCAPE) values around 600-800 J/kg this afternoon. 30-40 mph
localized gusts cannot be ruled out in the strongest cells. With
loss of diurnal heating, convection will quickly diminish in
early evening.
High pressure shifts farther offshore tonight into Monday,
allowing more southwesterly flow to bring in increasing
moisture. Meanwhile, a negatively-tilted midlevel shortwave will
lift southwest to northeast through the area Monday. This time,
precipitable water values will get closer to 1.5 inches. Shear
is not projected to be strong, but 6km flow of 30-35 knots may
be enough along with the shortwave, for the strongest cells to
have locally gusty winds and isolated hail. The Storm Prediction
Center has now included are area into a marginal risk for severe
thunderstorms Monday, which seems reasonable. This accompanies
the marginal risk of excessive rainfall that had already been
indicated by the Weather Prediction Center; i.e. about a 5
percent chance of excessive rainfall within 25 miles of a point.
Indeed most of the area will be fine, but with flow nearly
unidirectional through the column it will be possible for
locally heavy rainfall if training cells manage to line up.
Highs Monday will be in the 80s, with dewpoints rising into the
lower-mid 60s adding some mugginess to the air.
Behind the wave, any associated boundary will lose definition
and wash out over our vicinity Monday night. Some showers and
thunder will linger into evening, but they will eventually
succumb to loss of diurnal heating. Humid conditions will be
left in the wake of that activity, with patchy fog and lows in
the upper 50s-mid 60s.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
300 PM Update...
Upper level trough remains over our region on Tuesday allowing
for possible isolated or scattered showers/thunderstorms to
form in the afternoon. Instability during the day is expected to
build with steep mid level lapse rates, 25/30 kts bulk shear
and CAPE values of 889 J/Kg. Strong wind gusts are the main
concern with any storms that do develop. Highs are expected to
be well in the 80s throughout the region with lows falling into
60s. A ridge attempts to build in Tuesday evening and into
Wednesday, this is especially visible on the ECMWF. Southerly
flow advects warmer air into the region on Wednesday allowing
conditions to heat up with highs are expected to reach the upper
80s/lower 90s. Warm temperatures and high dew points will put
the heat index close to advisory criteria. Soundings show the
previous capping inversion present lifting in the afternoon,
therefore it is possible to see some pop up showers with the
available moisture. Lows are expected to return to the 60s
overnight.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
300 PM Update...
Thursday and Friday appear to be the hottest days of the week as
southerly flow continues to advect more warm and humid air into
the region. Temperatures are expected to climb into the upper
80s to low 90s with dew points in the upper 60s to lower 70s. A
heavier blend of the NBM 90th percentile was used to capture
these warmer temperatures. GFS soundings for Thursday and Friday
show CAPE values of approximately 1900 J/KG with a 30/40 kt
difference of 0-6 wind shear. Although plenty of CAPE is
available on Thursday, it is possible that the inversion
persists keeping showers and thunderstorms from developing. At
this time NBM has only has a 30% chance for Pops. Friday appears
to be more concerning in terms of possible severe weather, but
it is still pretty far out. A cold front is expected to make its
way through the area sometime from Saturday afternoon into
Sunday brining highs back into the upper 70s to lower 80s with
lows in the lower 60s. Some showers and thunderstorms are
possible with this frontal passage, although models struggle to
agree on timing.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
745 pm update...
Mainly VFR into Monday evening. This evening showers should die
before reaching SYR. Late tonight valley fog should become IFR
again at ELM from 9 to 12z and maybe as early as 7z.
Monday midday into evening showers and likely with a chance of
thunderstorms. Restrictions are likely but confidence on when is
low so did not put a TEMPO in. Convection starts midday in NEPA
and maybe BGM then another area develops west of there around
18z. A cold front comes through late in the day.
Light and variable winds tonight. Monday winds at 5 to 10 kts
starting south then shifting to southwest.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MJM/MDP
SHORT TERM...ES
LONG TERM...ES
AVIATION...TAC
Area Forecast Discussion
National Weather Service Columbia SC
1057 PM EDT Sun Jul 23 2023
.SYNOPSIS...
Drier air over the region will lead to limited rain chances
through mid-week. Atmospheric moisture returns to near normal by
late week but warming temps aloft may still work to suppress
convection. Temperatures will generally be near normal through
mid-week warming to above normal by late week and into the
weekend.
&&
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
Watching a line of showers and thunderstorms across the Upstate
this evening. This convection, in addition to more isolated
activity to the southwest in Georgia, is associated with a
frontal boundary and a weak area of low pressure to our west.
Rain, which may be heavy at times, is most likely over the
Northern Midlands during the next few hours. Guidance continues
to favor the development of low clouds and/or patchy fog
towards daybreak. Multiple stations across the forecast area are
already reporting scattered stratus decks therefore opted to
add patchy fog to the grids for most locations tonight based on
this and forecast guidance. Fog will be most likely in areas
that saw rainfall today in addition to normally fog prone
locations. Lows tonight will mostly be in the lower 70s.
&&
.SHORT TERM /7 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
The axis of an upper level trough will remain just west of the
forecast area Monday. A diffuse surface boundary will be near
the eastern edge of the forecast area. Dry air entering into the
region from the west will hinder convection across much of the
FA during the afternoon. PWAT values near 1.25 inches will keep
the chance of rain limited for western portions of the CSRA and
the western Midlands. There may be some thunderstorms that
develop on Monday afternoon across the eastern Midlands along
the surface boundary, remnant outflows or the sea breeze. With
dry mid-level air in place we can`t rule out a low threat of
isolated downburst winds from thunderstorms. Temperatures will
be slightly below normal on Monday with highs around 90.
Overnight lows in the low 70s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
The upper trough axis lifts out of the region heading into
midweek with drier air pushing in from the west, limiting
atmospheric moisture and rain chances. Below normal PWAT values
of around 1.5 inches or less suggest convective coverage may be
below climatology on Tuesday and Wednesday. Despite the dry air
we cannot rule out an isolated shower or thunderstorm through
mid-week. The global ensemble mean PWAT values return to near
normal late week suggesting a recovery in atmospheric moisture
over the region. The forecast area will be between two upper
ridges during the extended with 850 mb ridging strengthening,
leading to a subsidence inversion and capping. This pattern of
near normal moisture and warming 850 mb temps favors above
normal daily highs and isolated, afternoon convection. Highs for
late this week and into the weekend will be in the mid to upper
90s.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Convection is beginning to diminish across the region but
increasing confidence in IFR and possible LIFR conditions in
fog/stratus during the morning hours.
Convection is waning and shifting north of the terminals this
evening and not expecting additional impacts overnight at this
time. Lingering debris clouds will linger through midnight but
some clearing is expected later tonight. Drier air aloft atop a
moist boundary layer should support stratus/fog development and
HRRR and NBM along with MOS guidance all suggesting stratus/fog
development. Bring in MVFR cigs 04z-06z time frame lowering to
IFR/LIFR by 09z all terminals with IFR vsbys. Some improvement
should start occurring by 13z with mixing and a return to VFR
conditions by 16z all terminals.
Winds should diminish to light and variable overnight then pick
up to around 5 knots with a variable direction after 16z Monday.
Scattered cumulus cloud deck expected with some higher clouds
into the afternoon. Isolated convection possible Monday
afternoon, favoring the eastern Midlands.
EXTENDED AVIATION OUTLOOK...Isolated to scattered diurnal
convection favored each afternoon through the extended, with
restrictions possible in any heavier shower or storm.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Duluth MN
638 PM CDT Sun Jul 23 2023
.DISCUSSION...(This evening through Saturday)
Issued at 348 PM CDT Sun Jul 23 2023
Summary: Wildfire smoke from Canada will linger across the region
today into Monday. An Air Quality Alert remains in effect for all of
northeast Minnesota until 6 PM on Monday. Periods of scattered
showers and storms will be possible this afternoon, tonight, and
Monday afternoon. A few storms on Monday afternoon may become strong
to severe, capable of producing damaging winds of 60 mph and large
hail of 1" or greater. Otherwise, the main story this upcoming week
will be the heat.
Quiet, albeit smokey, conditions have been observed this afternoon.
Wildfire smoke from Canada has been drifting into the CWA as a weak
cold front has been sagging southward. Latest 18z surface analysis
from WPC placed this cold front around the Iron Range in MN, which
is consistent with recent visible satellite imagery. Convection has
initiated near the front just west of the CWA within an area of 2000
J/kg of sfc CAPE. These storms are expected to propagate into the
CWA over the next few hours as RAP profiles in KHIB show favorable
instability persisting into the evening. Despite the weak forcing
from the cold front, small hail and gusty winds will be possible
around the Iron Range into the Arrowhead late this afternoon and
evening. 0-6 km bulk shear is progged to increase to around 35-40
knots by this evening, which will coincide with MLCAPE up to 1000
J/kg. While confidence is low, it wouldn`t be surprising to see a
report or two of 1" diameter hail given the parameters.
In addition to the storms, wildfire smoke will continue to be a
concern today into Monday as mixing occurs following the cold front.
Skies have had a hazy appearance with numerous observation sites
across the CWA reporting reduced visibility and smoke/haze. Both the
RAP and HRRR smoke models have increased concentrations of near-sfc
and vertically-integrated smoke lingering over the region through
Monday. An Air Quality Alert remains in effect for the MN portion of
the CWA until 6 PM on Monday.
Additional chances for showers and storms will occur tonight as a
weak shot of mid-level vorticity moves through. Monday will see
increasing PoPs in the afternoon as diurnally driven showers and
thunderstorms develop. Convective parameters will be favorable by
the mid to late afternoon, with MLCAPE up to 1200 J/kg and 0-6 km
bulk shear of 30-35 knots. DCAPE will also be quite high tomorrow
afternoon, exceeding 1000 J/kg. These favorable parameters are
reflected in SPC`s Marginal Risk issued from the Brainerd Lakes, up
to the central Iron Range, and into all of northwest WI. Severe
hazards tomorrow afternoon include damaging winds of 60 mph and 1"
or greater in diameter hail. Timing and coverage of storms with the
Marginal Risk area is fairly uncertain at this time, since any
severe storms will be primarily driven by diurnal heating.
Other than the severe storm potential tomorrow, the main focus over
the next few days will be the increasing temperatures as a ridge
builds over the Upper Midwest. Confidence remains high that very
warm to hot temps will occur, especially on Wednesday. In DLH for
example, the 25th percentile of the NBM is showing a high on
Wednesday of 88 degrees, while the 75th percentile shows 94. For
Hinckley, high temps will be even warmer, with the NBM 25th
percentile showing 92 and the 75th percentile showing 99 on
Wednesday. These temps will also be accompanied by dewpoints
increasing into the mid 60s to near 70. With heat indices
approaching 100 in southern portions of the CWA on Wednesday, Heat
Advisories may be needed. Fortunately, these hot temps are unlikely
to persist for long, with highs returning to the 70s and 80s by the
weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 638 PM CDT Sun Jul 23 2023
A weak cold front stretched across northern Minnesota early this
evening and it`s forecast to sag south overnight. Convergence
along this boundary has set off showers and thunderstorms and they
are expected to continue tonight. They may diminish in coverage
for a time this evening then should increase some again later
tonight. Timing these showers/storms will be a challenge due to
the expected coverage and we have a mix from no mention in some of
the TAFS to VCTS along with a TEMPO. Later forecasts/amendments
will continue to refine timing. Smoke from Canadian wildfires will
keep visibility restrictions going tonight and fog is also
expected to develop. IFR or lower conditions in fog will develop
in spots tonight. The fog will lift Monday morning but some MVFR
visibility restrictions will remain in spots due to the smoke.
Additional showers/storms are expected to develop Monday, most
likely in the afternoon into early evening and over the southern
half of the Northland.
&&
.MARINE...
Issued at 348 PM CDT Sun Jul 23 2023
Quiet conditions are likely to continue on western Lake Superior
this week under light pressure gradients. The main threat will be
from any thunderstorm activity tonight through Monday. Wildfire
smoke from Canada will result in haze today into tomorrow. Patchy
marine dense fog development will be possible late tonight into
Monday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 78 57 86 / 20 20 20 0
INL 55 83 56 87 / 20 10 10 10
BRD 60 88 61 92 / 20 30 20 0
HYR 57 85 58 89 / 20 40 30 10
ASX 57 79 57 87 / 30 30 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
DISCUSSION...Unruh
AVIATION...Melde
MARINE...Unruh
Area Forecast Discussion
National Weather Service Goodland KS
1000 PM MDT Sun Jul 23 2023
.UPDATE...
Issued at 840 PM MDT Sun Jul 23 2023
Forecast concerns overnight tonight are on thunderstorm potential,
severity and areal coverage.
At 0230z the forecast area was under cirrus cloud cover with a few
thunderstorms entering far western Cheyenne county Colorado from
the west. These storms have had a history of wind gusts generally
up to 50 mph. DCAPE values per SPC mesoanalysis are around 1800
J/KG. Further north toward the North Platte area, we`re watching
scattered strong thunderstorms slowly moving toward the south.
These storms are near a MLCAPE gradient of 3000 to 4000 J/KG and
downstream DCAPE values around 1900.
For the rest of tonight, the latest HRRR model run (01z) maintains
the prior several runs of pushing the Colorado activity slowly
east, perhaps into western Kansas along a surface trough. The
greater concern is focused on the activity currently north of the
area. This activity is forecast to continue moving south-
southeast, perhaps due south per Bunkers right moving storms
forecast. This would be near the fairly extreme instability axis.
The 01z run of the HRRR has really decreased the wind gust
potential below severe criteria while the prior several runs had
gusts well in excess of severe criteria. All other hi-res 00z
model solutions had no thunderstorm activity at all. Given the
current radar mosaic, the HRRR is handling things better.
For the evening update, I`ve incorporated the latest HRRR run,
capping pops at 40% for now. As the activity gets closer and we
get more data, I may up pops accordingly. The primary hazard will
be wind gusts in excess of 60 mph but could be lowered if later
HRRR runs suggest it.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 145 PM MDT Sun Jul 23 2023
Similar to yesterday, but with even more uncertainty, is the
potential for thunderstorm development this afternoon and into
this evening. Northwest flow continues with nebulous forcing aloft
along with weak convergence boundaries at the surface, either of
which could be sufficient for convective initiation almost
anywhere in the forecast area. Environment is supportive of
supercells with effective shear of 40-50 kts and MLCAPE of
1500-2500 j/kg. CAMs have been all over the place as far as
guidance is concerned, and were not very good yesterday, so
confidence in any particular model or model run is very low.
Tonight, upstream storms rotating over the ridge may survive the
trek southeast and enter the area late as a low level jet tries to
develop. Otherwise, expecting mostly clear skies and low
temperatures in the 60s.
For Monday through Wednesday, upper ridge builds over the area
from the west with temperatures rising into the upper 90s and
lower 100s. Maxes may be tempered just a bit with all of the
recent rainfall and lack of stronger southwesterly component in
the surface winds to aid in downslope warming. Considered a Heat
Advisory for Norton and Graham counties in northwest Kansas where
forecast yields heat index maximum of 103 on Monday, just shy of
the criteria of 105. So, will hold off and let next shifts take a
closer look. There is a low chance that storms rotating around the
ridge will move into northern areas Monday night from Wyoming and
northern Colorado, but expecting most if not all locations to
remain dry on Monday. However, by Tuesday and Wednesday will see
some low chances of storms as the ridge flattens and allows
convection initiating on the higher terrain to the west to have a
chance to make it as far as the Kansas and Colorado border area.
Shear and instability forecasts are not particularly impressive
either day at this time, suggesting the probability for severe
storms will be low.
.LONG TERM...(Thursday through Sunday)
Issued at 150 PM MDT Sun Jul 23 2023
Long range guidance indicates that a robust upper level ridge..
situated over the 4-Corners, Rockies and Central/Southern Plains..
will persist late this week through the upcoming weekend. The
location and orientation of the ridge (per 12Z GFS/ECMWF guidance)
suggest that the mid-latitude westerlies (and any small amplitude
waves therein) will largely be relegated to higher latitudes (e.g.
north of I-80). While isolated/scattered diurnal convection may
develop on the lee slopes of the Colorado Front Range and adjacent
portions of the Palmer Divide during the late afternoon hours on
any given day.. synoptic environments characterized by weak
steering flow tend to confine/anchor such development in close
proximity to the mountains. With moderate to strong instability
and DCAPE over the region throughout this period, downstream
propagation into the Tri-State area cannot be ruled out,
especially from the northwest and north (i.e. eastern WY and NE
Panhandle) -- in closer proximity to the westerlies -- where
convective organization and outflow consolidation are [relatively]
more likely to arise. With the above in mind, expect above
average temperatures and below average chances for precipitation
(convection).
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1000 PM MDT Sun Jul 23 2023
KGLD...VFR conditions are expected through the period. A south
wind around 10kts at taf issuance is forecast to veer to the
southwest at similar speeds by 14z, becoming light and variable
from 15z-21z. After 22z, winds establish an easterly component at
speeds up to 10kts, veering to the southeast then south through
the rest of the taf period.
KMCK...VFR conditions are expected through the period. Convection
may be ongoing at taf issuance through about 07z with wind gusts
up to 45kts or so possible along with a brief period of moderate
to heavy rain which could create sub VFR cigs. After 08z, winds
generally light and variable with speeds up to 7kts or so.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...024
LONG TERM...VINCENT
AVIATION...99
Area Forecast Discussion
National Weather Service Gray ME
1037 PM EDT Sun Jul 23 2023
.SYNOPSIS...
A weak cold front approaches from the west on Monday and brings
the chance for afternoon showers and thunderstorms especially
across New Hampshire. Another weak front will approach Tuesday
and will bring another chance for showers and isolated
thunderstorms. Hot and humid conditions start building in for
late in the week.
&&
.NEAR TERM /TONIGHT/...
1035 PM Update... Another round of minor updates, this time
brought lows a little lower in the valleys... dipping just
below 50 in a few spots toward the north.
651 PM Update... Very little to update at this time with
clearing skies and nothing on the radar aside from the sea
breeze. Blended near term temperatures into the overnight trend,
and attempted to hone in on the fog/stratus threat overnight a
bit.
Previously...
Broad high pressure centered over the Mid Atlantic slides
eastward tonight into Monday as a mid level wave treks across
the Great Lakes. The CU field that has blossomed over much of
the area will dissipate this evening with the loss of heating
giving way to mostly clear skies and light winds. This will
favor radiation fog to form along most valleys with lows
dropping into the 50s across the north and low 60s across the
far southeast NH.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
The mid level wave will flatten some as it pushes towards New
England Monday. Return flow around the surface high offshore
will align with SW flow aloft to transport some moisture into
New England along with warmer air. Highs on Monday will run a
couple degrees higher than today with dewpoints creeping back
into the low to mid 60s. The approaching mid level wave will
likely lead to showers and thunderstorms developing over upstate
NY and Vermont by early to mid afternoon with this activity
spilling into the forecast by late afternoon.
The 12Z CAM suite generally agrees there will be sufficient
instability for thunderstorms, while there is a spread amongst
guidance with respect to ML CAPE and dry air aloft. The 12Z HRRR is
the most bullish with convective coverage as it brings pockets ML
CAPE up 1500 J/kg while most other CAMs show limited coverage with
ML CAPE below 1000 J/kg. As low level winds increase with the
approaching wave effective shear will grow to around 30 kts, which
could produce some stronger storms if enough instability can be
achieved. At this time SPC brings a Marginal Risk for severe storms
to the VT/NH border with just general thunder across the forecast
area. As there is little in the way of surface features for storms
to organize along, timing and placement of thunderstorms is
difficult to pin down with the greatest chances for stronger storms
in the White Mountains back towards the CT Valley. After some dry
weather and relatively low PWATs hydro concerns are low, other
than the typical heavy rainfall associated with thunderstorms.
Showers and thunderstorms will spread eastward tomorrow night and
generally dissipate with the loss of heating. Fog will be possible
again tomorrow night especially in areas that receive any
rainfall. Lows tomorrow night will generally be in the low to
mid 60s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
A zonal flow pattern takes shape through the early to mid
portion of the long term forecast which still looks to bring
heat into our region.
A short wave trough will approach from the west on Tuesday and
will aid in the development of widely scattered showers and
thunderstorms, but overall most areas look to remain dry with
highs well into the 80s.
Looks mainly dry and warm on Wednesday as we should be in
between two short wave troughs. However, on Thursday some
ensemble members indicate another short wave trough approaching
with the attendant threat for thunderstorms amidst highs in the
lower 90s and heat indices likely 95 or higher. Several ensemble
members and some deterministic members of the 12z suite also
calls for a chance of showers and thunderstorms on Friday, maybe
even MCS material. But we`re a long way from ironing out any
details other than to say we may have to deal with some severe
weather and flash flooding toward the end of the week.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Short Term...Valley fog will likely bring LIFR conditions to
KLEB and possibly to KHIE late tonight. Marine fog or low cigs
will also bring potential restrictions to KRKD. Elsewhere VFR
is expected with VFR likely for all Monday. Some SHRA and TS
activity will move in from the west with most likely impacts to
KLEB and KHIE. Valley and marine fog will bring potential for
flight restrictions Monday night for typical terminals with VFR
elsewhere.
Long Term...Mainly VFR through Wednesday, although valley fog
at KHIE/KLEB will be possible most nights. Scattered convection
Tuesday afternoon could briefly bring MVFR-IFR conds. Thursday
and Friday may feature some showers and thunderstorms with
associated lower conditions as well as the possibility for
coastal stratus and fog.
&&
.MARINE...
Short Term...High pressure south of the waters will maintain
quiet conditions with winds and seas remaining below SCA
thresholds through Monday night.
Long Term...Winds/seas stay below SCA levels through Wednesday,
but SW flow could approach SCA levels on Thursday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
UPDATE...Casey
NEAR/SHORT TERM...Schroeter
LONG TERM...Ekster
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
1025 PM EDT Sun Jul 23 2023
.SYNOPSIS...
Temperatures will be heating up this week. A mid-level
disturbance and weak surface low will generate showers and
thunderstorms Monday afternoon and evening. While a few
afternoon and evening storms cannot be ruled out later in the
week, the next better chance of showers and thunderstorms will
hold off Friday night and Saturday.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Still some isolated showers and thunderstorms lingering
across northeast and southwest portions of our fa. Think these
will gradually taper off through the next few hours. However,
the HRRR is suggesting some isolated showers/thunderstorms
redeveloping later tonight ahead of some weak mid level energy.
Will therefore, allow for some slight chance pops across mainly
our western/southern areas later tonight and into Monday
morning.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
12Z guidance has picked up on yet another short wave dropping
southeast into the area Monday afternoon. This is inducing a
weak surface low over Indiana. CAPE is forecast to be over 2000
J/kg. So expecting showers and storms to develop and move across
the area during the afternoon and evening before pushing
southeast out of the region. At this point, expect greater
coverage to be in the western counties. Shear is marginal, but
there could be a few stronger storms.
Highs will generally be in the mid 80s with lows in the mid 60s.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
The previously mentioned (albeit, weak) shortwave, best seen around
700H will be moving through the larger flow and approaching the area
Tuesday. It appears that this wave will continue to weaken as it
reaches the Ohio Valley region with its associated surface
disturbance losing organization as well- precipitation from this
looks to arrive Tuesday evening into Wednesday (again, without much
organization to it). Despite the weakening trend, this still acts to
set up a gradient between the decaying disturbance to our west and
an area of high pressure off to our southeast- effectively
sandwiching us under low level southwesterly flow stemming from the
Gulf of Mexico. As warm, moist air flows into the region our
temperatures and dew points increase. Highs from Wed- Fri reach the
low 90s, but "feels-like" will end up being mid to upper 90s.
Overnight lows only fall to the low/mid 70s.
While this is occurring near the surface, aloft a more zonal set up
develops as a broad area of high pressure and weak flow takes hold
over much of southern CONUS with areas of low pressure over Canada.
Additional shortwaves moving through the larger flow will likely
keep rounds of showers/storms in the forecast- although there is no
strong signal on any particular system.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Isolated to scattered thunderstorms are occurring over parts of
the area this evening. The most widespread activity is across
southeast Indiana. This is advecting southeast toward KCVG and
possibly KLUK. It is moving into a somewhat less favorable
environment so there is some uncertainty as to how well they
will maintain themselves as they approach KCVG/KLUK.
Nonetheless, will allow for a temp -tsra and KCVG and a VCTS at
KLUK for the foist couple of hours of the TAF period. Meanwhile,
activity across central Ohio is more isolated but this may
still affect KCMH/KLCK over the next hour or so.
Pcpn should dissipate heading into tonight with skies becoming
mostly clear. This could lead to some areas of br in places
that received better rainfall this evening as well as some of
the river valleys in the south. For now will only include some
MVFR vsby restrictions at KLUK late tonight/early Monday.
Sct-bkn cu will redevelop through the day on Monday with
scattered showers and thunderstorms possible again in the
afternoon and evening.
OUTLOOK...No significant weather expected.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...
NEAR TERM...JGL
SHORT TERM...
LONG TERM...CA
AVIATION...JGL
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1101 PM CDT Sun Jul 23 2023
.SYNOPSIS...
Issued at 1040 PM CDT Sun Jul 23 2023
A ridge of high pressure will build into the Midwest over the next
several days to bring increasing warmth. Just how hot it will get
any day this week will depend on where thunderstorms track, which at
this point remains difficult to determine. Nonetheless, warm and
muggy nights following hot, humid days will be uncomfortable for
those spending time outdoors, and oppressive for vulnerable
populations including the elderly, very young, outdoor workers, and
those without air conditioning.
&&
.UPDATE...
Issued at 952 PM CDT Sun Jul 23 2023
Isolated thunderstorms are still festering over east central IL
this evening, though intensity has diminished over the past hour.
00z KILX sounding indicated 4k J/kg surface based CAPE, with just
enough vertical wind shear to support a few prolific hail
producing storms. Largest report received was 2.5" (tennis ball)
hail in Chatham around 730 pm. With the lower levels stabilizing
as the evening has progressed, MLCAPEs around 1500 J/kg over east
central IL will promote isolated heavy downpours and cloud to
ground lightning for the next couple hours before storms fade.
Light winds and mostly clear skies will then dominate the region
overnight, with lows in the mid 60s.
25
&&
.DISCUSSION...
Issued at 223 PM CDT Sun Jul 23 2023
At 225 PM, radar imagery revealed a couple showers developed near
the Illinois River. As these isolated showers meander gradually
southeast through the afternoon, a couple of them could be on the
feisty side with briefly heavy rain, gusty winds, and possibly
even some small hail, but a lack of shear will preclude anything
sustained/organized with a low (<5%) chance that anything becomes
severe.
------------------------- [Key Messages] -------------------------
1. 30-40% chance for thunderstorms Monday night-Tuesday morning.
2. Several 20-30% chances for thunderstorms scattered throughout the
work week. Attempting to nail down the timing of each disturbance
would be futile at this point.
3. Warm to hot weather expected by Wednesday and likely lingering
into the weekend. Confidence in the high temperature forecast on any
given day will be low, however, given the possibility of
thunderstorm activity.
-------------------------- [Discussion] --------------------------
After storms finally wind down this afternoon/evening, we should get
a break from shower activity until Monday evening when a weak
disturbance brings a lobe of enhanced 500 hPa (h5) vorticity along
the crest of the ridge across the region. With increasing
southwesterlies in the 925-850mb layer, warm advection will favor
some elevated instability, though the quantity of that instability
is a subject of dissension among the short term models; the HRRR
says 700-1200 J/kg of MUCAPE, while the NAM argues 1500-2500 J/kg of
it will manifest across central Illinois Monday night. Right now,
the bulk of the activity is progged to materialize to our southwest,
but the chance is there for any part of our CWA to see storms. We`ll
defer to later shifts to take a look at fresh model guidance to
assess whether PoPs need to be increased for this period.
Cluster analysis suggests ensemble agreement in the trend for
gradually increasing h5 heights across central Illinois through the
upcoming work week as a ridge builds in from the west. By day
5/Thursday, the mean of low resolution ensemble forecast (LREF)
system brings h5 heights to around 588 decameters (dam) as far north
as the I-74 corridor. At this point, however, some discrepancies
within the ensemble become apparent in cluster analysis: The largest
cluster, comprised of 46% of the LREF grand ensemble (GE), is driven
mainly by the European (EPS) and Canadian (CMCE) systems, and has
fairly zonal flow across central Illinois with the 588 dam h5
contour as far north as Rochester, MN; the second largest (34% of
the LREF), which includes the remainder of the EPS and a handful of
GEFS members, is slower with bringing the ridge into the region,
having its axis across the high Plains with our area under more
northwesterly flow on its eastern periphery; such a pattern would
favor not only less oppressive heat, but also episodic ridge-riding
thunderstorm clusters. Clusters 3 is composed of a greater
proportion of GEFS members - albeit only 12% of the total LREF GE -
and features a much slower build up of the ridge, having a trough
over the Great Lakes and the axis of our ridge still across the
Great Basin. Despite its cooler start, the GEFS goes on to become
much more amplified with the ridge over central Illinois by Friday-
Saturday, with many members having h85 temps warming into the upper
20s degC and some even bringing them to 30+ degC. Fortunately, it
appears there have been recent observations that this ensemble`s
soil model is erroneously excessively dry...leading to a much hotter
boundary layer than could be expected in the Midwest during "corn
sweat" season, so while it can`t be completely discounted it would
appear that it`s skewing the LREF distribution right and leading to
a high bias in NBM.
For now, we`ll lean more towards the EPS and CMCE`s forecasts, which
again have the ridge building in faster though not becoming as
strong as members of the GEFS would suggest. This means that it will
be a hot week - especially when one considers the potential for
multiple overnight lows in the mid 70s as dewpoints shoot up with
boundary layer moisture flux from crop evapotranspiration - though
not as oppressive as the most extreme members of the LREF would
suggest. A Heat Advisory is not out of the question, especially if
the excessively warm overnight lows materialize for several days in
a row, but at this point there`s not much reason to believe we`ll
wind up with an Excessive Heat Warning, at least through this
weekend. One source of frustration from a forecaster`s perspective
this week is the perpetually looming risk of a thunderstorm -
whether a ridge riding mesoscale convective system (MCS), or just a
pop up storm that manages to fire along a southward-drifting outflow
boundary from MCS activity further north - which could prevent
temperatures from rising above the mid 80s on any day this week.
Nonetheless, folks should be prepared for a hot late week, as NBM
yields 20-30% (80%+) probabilities for surpassing 100 (90) degF
in (the arbitrarily chosen sample site of) Peoria each day
Wednesday through Saturday.
By the upcoming weekend, uncertainty begins to increase further, and
not only in the temperature forecast due to potential for
convection, but also in the upper pattern. The EPS and CMCE suggest
heights will lower and we`ll cool off, potentially with the passage
of a cold front, while the GEFS by and large suggests we`ll turn
hotter as the ridge continues to build in. While there is the known
problem in the GEFS` soil moisture model which is leading to
excessive warmth in its ensemble during the extended period, the
prospect of the warm/hot weather lingering longer than what the
mean of the other ensemble systems of the LREF would suggest
should not be dismissed as several times it`s been observed that
ridges are slower to build in and slower to be flattened than what
the extended global ensembles would suggest. NBM suggests 80% or
greater chances for high temperatures of 90+ degF in Lawrenceville
through next Monday, 7/31, and the CPC`s 6 to 10 day outlook
features a 60-70% chance for above normal temperatures. It`s way
too early to predict severe weather in this kind of pattern, but
still one can speculate that there`s the possibility that in this
pattern any one of the ridge riders which the deterministic models
have been showing in our vicinity this weekend/early next week
could generate severe weather, especially in the form of strong
winds. We`ll continue to monitor that potential.
Bumgardner
&&
.AVIATION... (For the 06z TAFs through 06z Monday Night)
Issued at 1100 PM CDT Sun Jul 23 2023
Light winds and VFR conditions will dominate the area for most of
the next 24 hours. The exception is patchy light fog that is
expected to develop late tonight. This could drop some terminals
into MVFR for a time, and included TEMPO groups for vis reductions
08-12z.
25
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
1030 PM EDT Sun Jul 23 2023
.Forecast Update...
Issued at 1029 PM EDT Sun Jul 23 2023
There are still some isolated showers and thunderstorms lingering
within central Indiana this evening along a weak remnant boundary.
These will continue to percolate as they move SSE along the boundary
through 04-06Z.
New development of showers and thunderstorms is still possible this
evening north of a modest jet streak. Any showers/thunderstorms that
due develop should stay under severe criteria with the only threats
being lightning and occasional high rain rates leading to localized
areal flooding.
Otherwise, no major changes needed to the ongoing forecast other
than fine tuning of POPs and associated sky cover forecast.
&&
.Short Term...(This evening through Monday)
Issued at 254 PM EDT Sun Jul 23 2023
Rest of Today.
As of early this afternoon, the MCV that helped bring a few showers
to the northern counties this morning was crossing into Illinois.
Convective temperatures have been met according to ACARs soundings
with 1200-1500 J/kg of SB CAPE, but a fairly dry column is limiting
the effective instability with only 200-300 J/kg when looking at ML
CAPE. The best forcing into the afternoon will be near and to the
south of the exiting MCV, so will focus POPs across the eastern
counties with lesser amounts further to the west. The last few HRRR
runs have latched onto the exiting MCV and each successive run
continues to lower rain chances across central Indiana with a lack
of a good initiator for convection.
Tonight.
Generally conditions are expected for the overnight hours with the
potnetial for a few additional showers and storms along an
instability gradient across central Indiana. The diurnally driven cu
field overhead will gradually dissipate after sunset as the PBL
begins to decouple. With the lower expected coverage for storms
this afternoon, little convective overturning will create a slightly
more favorable environment for a few elevated showers and storms.
Initiation for these storms will be along the eastern periphery of a
slightly stronger 700-850mb jet which will peak in strength after
midnight. Not expecting high coverage or anything more than a few
rumbles of thunder, but will be worth watching through the night.
Shallow ground fog looks to return again late tonight into tomorrow
morning with similar model signals to the last few morning with
mostly clear skies, calm winds, strong inversion, but marginal
moisture.
Monday.
The pattern will gradually begin to shift tomorrow with warmer
weather working its way into central Indiana. Dry weather is
expected for much if not all of central Indiana through the morning
hours, but more robust southerly flow will bring dewpoints into the
70s along with warmer temperatures along with renewed rain chances.
Model soundings show upwards of 2000 J/kg of instability during peak
heating, but a lack of initiation source will limit convective
development and coverage for storms. Models may also be overdoing
the afternoon heating with the ridge still well out to the west and
weak northwesterly flow aloft through the daytime hours.
&&
.Long Term...(Monday night through Sunday)
Issued at 254 PM EDT Sun Jul 23 2023
* Hottest weather of the summer thus far later this week.
* Frequent but low chances for thunderstorms through the week.
Continued expectations for this week are for a very large upper
level ridge centered over the Southwest/southern High Plains, with
upper level troughing of various intensities over the northeastern
US, with central Indiana stuck in between in an upper level
northwest flow regime much of the week.
Surface flow will be largely southerly or southwesterly much of the
period, with warm advection maintaining a hotter and more humid
airmass through the week, at least until potential passage of a cold
front very late in the period.
As a result of this northwest flow aloft and warm, moist southerly
flow at the surface, frequent chances for thunderstorms will be
required through much of the long term period, but any one period
will not have more than low chances, owing to significant
uncertainty with respect to convective evolution, as the resultant
forecast depends both upon subtle disturbances that longer range
models generally handle poorly, and evolution of prior convection,
which models also struggle with significantly.
By mid week, afternoon highs in the low to mid 90s will be
commonplace, with peak heat index values approaching or exceeding
100 degrees at times. This is unlikely to rise to the level of
headline necessity, but will be quite hot and sticky, particularly
given the relative lack of such heat thus far this season. It is
also worth noting that heat illness is possible even with similar or
lower heat index values, particularly with prolonged exposure or in
those who are particularly susceptible.
Folks across central Indiana should take care to limit heat exposure
this week and take frequent breaks when this is not possible.
&&
.Aviation...(00Z TAF Issuance)
Issued at 702 PM EDT Sun Jul 23 2023
Impacts:
-Isolated VCTS at KBMG through 02Z.
-MVFR vsbys from 10Z to 13Z.
Discussion:
Clouds and any lingering showers/thunderstorms will then clear after
sunset. Winds will remain light and variable through the period with
a predominantly southerly direction. Patchy fog with MVFR vsbys will
return late tonight and continue through the early morning hours.
More thunderstorms are possible beginning around 22Z tomorrow
afternoon through the evening, primarily near KBMG, KHUF and KIND.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Updike
Short Term...White
Long Term...Nield
Aviation...Updike
As discussed in previous forecast discussions, tomorrow night
continues to trend drier. While an 925-850mb LLJ is expected to
develop across the mid-Mississippi River Valley, forecast model
guidance continues to show the development of a warm frontal zone
well southwest of our area (central Iowa to west-central Illinois),
which should focus nocturnal convective development outside our
area. Notwithstanding a big adjustment in the forecast position of
the front, we favor a dry night. Overnight lows will drop into the
mid 60s overnight.
Borchardt
&&
.LONG TERM...
Issued at 307 PM CDT Sun Jul 23 2023
Tuesday through Sunday...
The main story through mid-week into the upcoming weekend is the
development of warm and humid conditions with several conditional
periods of convection within the periphery of a "ring-of-fire"
pattern. While the impressive stretch of oppressive heat across
the southwest CONUS the past couple weeks will migrate eastward
with the an upper ridge, the placement of the core of the ridge
(central High Plains) and shape (broad with somewhat zonal flow
across the northern CONUS) continues to put doubt on how far north
and east the more significant heat will reach.
In the absence of active convection this far south late in the
week, Thursday and especially Friday will be some of the warmest
(heat index) conditions so far this year. Heat index values may
reach Heat Advisory criteria (105F) in portions of the area,
particularly Friday. But, strengthening mid and upper-level flow
through the northern CONUS on the continued edge of steeper mid-
level lapse rates and increasing ET/Gulf moisture through the
region will set the stage for successive rounds of active
convection from the northern Great Plains into the Great Lakes
region mid to late week.
At this time, an initial trough on Wednesday may bring the first
round of convection. Focus will then be on potential MCS activity
developing well northwest of the CWA on Thursday, with upstream
trends dictating storm chances into our area Thursday night and
wherever any effective outflow focuses new convection Friday and
Saturday. Will maintain generally slight chance or chance PoPs
through much of the period while still remaining slightly
conservative with temps Friday and Saturday.
Kluber
&&
.AVIATION...
For the 00Z TAFs...
Aviation Forecast Concerns:
* Lake breeze wind shifts both this evening (?) and Monday
afternoon.
Despite weak wind surface wind field in baggy surface pressure
gradient this afternoon, Lake Michigan lake breeze has struggled
to push inland toward KORD/KMDW. Current TORD radar data shows
the boundary only about 7 miles east of KORD and perhaps 3 miles
east of KMDW and still moving very slowly west, though lack of a
more solid push will definitely make for a late (01-02Z) passage.
With lake breeze arrival near sunset, winds may tend to just go
light and variable, which they should do after dark either way.
Weak surface ridge across northern IL Monday looks to support an
evening weaker synoptic wind field, which should allow the lake
breeze to make both KORD and KMDW in the afternoon. Did push the
timing back an hour from previous forecast however, based on
latest HRRR guidance. East-southeast winds should remain light
southeast into Monday evening.
Otherwise, VFR conditions are expected through the period. May be
some shallow patchy fog south of the terminals, but none expected
at the forecast sites.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
813 PM EDT Sun Jul 23 2023
.SHORT TERM...(This afternoon through tonight)
Issued at 250 PM EDT SUN JUL 23 2023
Water vapor and RAP analyses show the shortwave north of Lake
Superior, with surface obs and visible satellite indicating the cold
front to be draped from south-central Ontario, southwest through
central Lake Superior and into the western UP. Agitated cumulus is
apparent across most of the central and eastern UP, with some
isolated showers and thunder across the interior UP and along the
lake boundaries. One storm that just passed over the office brought
a quick downpour and some rumbles of thunder, but was otherwise
fairly benign. As the cold front moves through, guidance continues
to indicate scattered showers and thunderstorms to become somewhat
more linearly organized and track E/SE towards Lake Michigan through
the evening hours. Severe storms are still looking unlikely, but
with SBCAPE already up to 1000-2000 j/kg, we may see some stronger
winds at times associated with thunderstorm outflow. Small hail and
frequent lightning would also not be surprising.
Showers sand storms quickly wrap up into the evening with the loss
of daytime heating. Skies largely clear out, and with light winds,
temperatures should be able to fall to near the dewpoints - so,
patchy fog is expected especially across the interior UP and where
we`ve been able to pick up on some QPF this afternoon. Additional
showers start to work in from the west into the early hours of
Monday with yet another shortwave moving into WI.
.LONG TERM...(Monday through Sunday)
Issued at 339 PM EDT SUN JUL 23 2023
While the general pattern over North America remains the same for
these next several days, model guidance is having a hard time on
agreeing on one solution for our area from Monday onward. While a
robust, stacked low moves into the Canadian Rockies Monday and
Monday night, shortwaves are still projected to move through or near
our area early this week. As the low splits the ridging over the
western US early this week, the southern half of the ridge is
expected to move towards the central US and become more zonal with
time. By the middle of this week (up until very recently), model
guidance really starts to diverge. The GFS suite of solutions keeps
the low somewhat robust, with part of it phasing with another
stacked low over Hudson Bay and northern Quebec before before
dragging its cold front over the UP Thursday/Thursday night. The
earlier Canadian and European solutions were were drastically
different, bringing the cold front over our area Saturday and next
Monday instead; the 00z European run had us waiting on another low
to move through the Pacific NW before having the cold front come
down early next week. However, the most recent 12z runs have finally
aligned more closely with the GFS solution; while the cold front is
much more subtle and not as strong in the Canadian and European
suites, these models have begun to bring the front over the area
Thursday night into Friday. Therefore, given the very recent model
convergence towards a Thursday/Friday cold front, we should see
additional showers and thunderstorms develop near the front over our
area around this time. As we get behind the front, model guidance
diverges for our area once again.
A weak shortwave moving through WI looks to start out the long term
period, possibly bringing showers and a few thunderstorms to the
west and central UP during the day. Most of the CAMs keep the
convection south of the WI border Monday, but some of the global
model guidance and select CAMs like the HRRR and NAMNest have a few
showers and thunderstorms occurring as far north as the cities of
Houghton and Marquette. More frequent convection looks to occur
during Monday afternoon and early evening, but should be limited to
just south of to along the WI border. While severe weather isn`t
expected, with a left-exit region of a jet streak moving overhead,
CAPE around 1000 J/kg in spots, and 0-6 km bulk shear getting to
around 35 kts, we may see a few strong thunderstorms near the WI
border. However, if the CAM guidance is to be believed, these strong
storms should be seen south of the WI border. Therefore, while
strong thunderstorms are possible Monday afternoon and early evening
along the WI border, the chance for winds and hail just below severe
criteria is pretty low. Besides the convection, some haze is
possible over the western half of the CWA Monday into early Monday
night due to the wildfire smoke from northern Alberta lingering over
the area. This wildfire smoke could cause some breathing concerns to
those sensitive to it. The haze from the smoke looks to dissipate
over our area by late Monday night. Speaking of which, expect rain
chances to die-out across the UP as instability becomes minimized
during the overnight hours. With temps cooling down to the dewpoint,
it`s possible that some patchy fog forms over the west and central
late tonight, particularly in the areas that received rainfall
Monday (this is also possible in the far east near Tahquamenon Falls
too, as they might see a shower/thunderstorm or two late Monday
afternoon/early evening). Near dawn Tuesday, some convective
redevelopment looks to occur near the WI border. This could bring
showers and thunderstorms back into our west by Tuesday morning as
another subtle shortwave tries to move through the Upper Midwest.
As off-and-on rain chances continue Tuesday into Wednesday via
shortwaves rolling through the region, with CAPE getting up to 1000
J/kg during the afternoon to early evening hours and 0-6 km bulk
shear around 30 kts, a few strong thunderstorms with sub-severe
hail, winds, heavy downpours, and frequent lightning are possible.
As this occurs, with the ridge upstream deconstructing to a more
zonal flow as it moves towards us during the middle of this week,
expect temps to subsequently increase each day. This is captured
fairly well by the ECMWF EFI and SoT. By Wednesday, there is an EFI
around 0.7 and SoT around 0 over the western UP; by Thursday, the
EFI increases to around 0.7 to 0.8 with the anomalously warm temps
moving over the rest of the UP. Therefore, don`t be surprised for
highs to get into the 90s over the west Wednesday and the rest of
the UP Thursday.
Once we get into the late week, expect a cold front to move over us
sometime Thursday/Friday. However, should the cold front not be as
strong as the GFS is predicting, expect the well above normal temps
to remain across our area, although based on medium model guidance,
the temps should slowly decrease as we move into this upcoming
weekend. In addition, we could see a few subtle shortwaves move
across the region this weekend into early next week, keeping low-end
precip chances across our area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 812 PM EDT SUN JUL 23 2023
Outside of any fog formation tonight, conditions will be at VFR
levels. Best chances for any fog will be at IWD and CMX where a
tempo was inserted for IFR/LIFR conditions. Elsewhere, will keep
SAW at VFR levels for the duration of the TAF period for now.
Light and variable winds will have no impacts.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 339 PM EDT SUN JUL 23 2023
As weak shortwaves move through the region for the first half of
this week, expect light winds of 20 kts or less to remain across
Lake Superior. As the shortwaves roll through the region, some
thunderstorms could be seen the rest of this afternoon through
Monday over the western lake near the lakeshores, and again across
the whole lake Tuesday night to the middle of this week. Come
Thursday/Friday, we are expecting a cold front to move across the
lake. Whenever the front does move through the lake, expect to see
additional showers and thunderstorms, with winds over 20 kts being
possible ahead of an immediately behind its passing.
Otherwise, the only other thing we could see over Lake Superior is
some haze over the west due to wildfire smoke from northern Alberta
today into Monday; this smoke may cause some breathing concerns for
those sensitive to it.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...LC
LONG TERM...TAP
AVIATION...TDUD
MARINE...TAP
Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
927 PM EDT Sun Jul 23 2023
...New UPDATE...
.UPDATE...
Issued at 919 PM EDT Sun Jul 23 2023
Forecast is tracking along nicely this evening. There`s nothing
on radar and no real reasons to make any changes. Forecast lows
seem like they`re in good shape, but it`s worth noting that the
latest run or two of the HRRR show temperatures a few degrees
warmer tonight than currently forecast. Since they`re the
outlier, and the difference isn`t some +10 degree change, decided
to keep the forecast as is. That`s about it for the evening
update.
&&
.SHORT TERM...
(This evening through Monday)
Issued at 249 PM EDT Sun Jul 23 2023
Fairly quiet weather with very minimal diurnal convection
expected this evening and again Monday afternoon. After a
comfortable morning in the 60s, it will be a warmer day tomorrow
as 500 MB high pressure begins to build in from the western U.S.,
pushing our trough to the east. Maybe some patchy fog forming
before sunrise.
&&
.LONG TERM...
(Monday night through next Sunday)
Issued at 249 PM EDT Sun Jul 23 2023
Key Messages:
1. Ridging builds back in across the Tennessee Valley this week with
a trend of increasing temperatures and dew point values.
2. Isolated chances for a shower or thunderstorm this week primarily
across higher terrain of the mountains and plateau.
Discussion:
As the week comes along, upper level troughing will retreat north
and the persistent high pressure out west will extend eastward.
Heights will rise and flow will become rather weak with surface high
pressure strengthening at the surface as well. Low-level moisture
will make a return with increased southwesterly to westerly low-
level flow during peak mixing. With all of this in mind - rising
heights aloft and low-level moisture, we can expect an increase in
relative humidity each day this week thus, heat indices. Portions of
the Southern Valley will exceed 70F degree dew points which will
easily translate to mid to upper 90s heat indices.
Increasing low-level moisture and localized ascent along the
mountains and plateau, will provide increased chances for showers
and thunderstorms each afternoon and evening during peak heating
hours. Chances will be best in the higher terrain, but cannot
completely rule out elsewhere.
Although far out in the forecast and models are just understandably
not in agreement, a shortwave may approach the area from the
northwest next weekend over topping the ridge, which may bring
better chances for showers and thunderstorms for non-higher
elevation spots in the forecast area. This will all depend on how
far south the trough can extend again, kicking the ridge back
west.
&&
.AVIATION...
(00Z TAFS)
Issued at 717 PM EDT Sun Jul 23 2023
VFR conditions should prevail at all terminals, except for perhaps
an hour or two of MVFR fog at KTRI around daybreak. The signal is
pretty weak in guidance, but it is there and we`ll also have
prime radiational conditions overnight so it seems to be a
reasonable forecast at this point. Otherwise, models forecast a
gradual decrease in deep layer moisture through tomorrow afternoon
and evening. Could see some FEW060 develop during the afternoon
but think they`ll be largely clear of terminals so will leave it
as SKC. Winds will be light during the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 88 66 90 68 / 10 10 10 0
Knoxville McGhee Tyson Airport, TN 86 65 88 66 / 20 10 10 0
Oak Ridge, TN 85 64 88 66 / 20 10 10 0
Tri Cities Airport, TN 85 62 86 63 / 30 10 10 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...CD
LONG TERM....KS
AVIATION...CD
Area Forecast Discussion
National Weather Service Tucson AZ
200 PM MST Sun Jul 23 2023
.SYNOPSIS...Excessive Heat Warning continues through Wednesday for
parts of the area with some record high temperatures likely. Hot
temperatures will continue with scattered afternoon and evening
thunderstorms through the week although fewer storms early in the
week and more toward the end of the week. Strong winds and locally
heavy rain with some storms. Somewhat cooler temperatures and more
thunderstorm activity is beginning to look possible next weekend.
&&
.DISCUSSION...The morning goo (clouds and precipitation) has done a
good job of holding off convection a bit, but it shouldn`t last for
much longer. Would expect some storms to develop over the higher
terrain that cleared off first which is already occurring far eastern
mountains and that should progress westward with time. The HRRR has
recovered from this morning and seems realistic in depicting storm
development over the next couple of hours and continuing into the
evening, primarily for the western half to two thirds of the area.
Limited instability should help keep the storms from getting to
vigorous but there is still enough DCAPE for gusty outflows here and
there. Prolonged heavy rain should not be an issue due to the PW and
wind field combination.
Monday into Tuesday, the upper level high currently centered near the
Four-Corners area will migrate south a bit, ending up centered over
New Mexico Tuesday into Wednesday where it will linger the rest of
the week. While this will maintain a general southeast flow, the
strength of the high will pose problems through Wednesday. Due to the
high heights and thicknesses, afternoon temperatures will continue
to run near record levels while the warm mid levels will help to
suppress thunderstorm activity, the reason for lower pops those days.
As we begin to approach the weekend, the high is progged to weaken in
place which should allow temperatures to cool a bit and convection to
develop more easily. For next weekend there are some differences in
the deterministic models however ensembles are pointing toward the
high weakening and moving toward a more favorable position with a
potential easterly wave impacting the area. This would allow for
more convective development, generally wetter storms and afternoon
temperatures easing back closer to normal if it comes to pass as
currently progged. Will keep the fingers crossed. CPC`s 6-10 day
outlook leans that way as well, lending some support for that
potential.
&&
.AVIATION...valid through 25/00.
SCT-BKN clouds at 8k-12k ft AGL persisting thru the end of the
forecast period. SCT SHRA/TSRA expected through 24/06Z, with
potential impacts for mainly KOLS and KTUS. There is the potential
for TSRA wind gusts to 45+ kts, brief VSBY reductions to 3SM or less
due to heavy rainfall and mountaintop obscurations into this
evening. Outside of thunderstorm outflows, SFC wind generally less
than 12 kts and variable in direction thru the forecast cycle, with
directions in the afternoon and early evening favoring south thru
east at the KOLS, KSAD, KALK and KDUG terminals and west to northwest
at the KTUS terminal. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...Scattered afternoon and evening thunderstorms are
expected each day through Thursday, potentially becoming more
numerous Friday onward along with being better rainfall producers due
to increased moisture. These storms will be capable of producing
strong, gusty and erratic outflow winds of 45 mph or more. Very hot,
near record temperatures will continue through mid week then should
cool a bit into next weekend. Although sustained 20-foot winds will
generally be less than 15 mph this week, afternoon gusts to around 25
mph may occur. Valley min RH readings will range between 10-20
percent through Wednesday, 15-25 percent Thursday through Saturday
and 25%+ Sunday.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 10 PM MST Wednesday for AZZ501-502-
504>506-509.
&&
$$
Public...Rasmussen
Aviation...Cerniglia
Fire Weather....Cerniglia
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