Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/15/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
839 PM CDT Fri Jul 14 2023
.UPDATE...
Issued at 837 PM CDT Fri Jul 14 2023
Overall the forecast is doing fine and only minor adjustments have
been made. Latest HRRR model continues to depict very isolated
overnight activity, but for now will ignore and keep forecast dry.
&&
.SHORT TERM...(This Evening through Saturday Night)
Issued at 253 PM CDT Fri Jul 14 2023
Key Messages:
* Canadian wildfire smoke will result in not only a milky sky, but
reduced visibility and air quality concerns as the smoke moves to
the surface.
Showers and thunderstorms developed shortly after 18Z mainly between
Dupree and Whitlocks Bay Rec Area, and continue to sink southeast.
Small hail, lightning, brief heavy rain, and gusty winds will be the
main threat. The strongest winds above the surface could easily make
it to the ground with stronger showers and any thunderstorms, on the
order of 50 mph. The threat will continue to sink southeast this
afternoon and mainly out of our forecast area by 22Z. Additional
showers may develop to our northwest, enhanced by several small
shortwaves moving through the northwest flow at 500mb. The loss of
daytime heating should put an end of any lingering showers or
storms. While the HRRR continues its idea of less shower or
thunderstorm activity, many of the CAMs do show the isolated to
scattered precipitation.
Will continue to heavily rely on the HRRR/RAP smoke forecasts for
the trends over the next couple of days. While there could be some
improvement/clearing of smoke over the ND/SD border Saturday
afternoon, the break looks to be limited. Will continue to monitor
the forecast and observation trends, as visibilities may go below
the 3-4SM that has been common at KABR since 1730Z.
.LONG TERM...(Sunday through Friday)
Issued at 253 PM CDT Fri Jul 14 2023
In general, good agreement still exists in the overall upper level
flow pattern during the extended period. Period starts off with
northwest flow aloft Sunday and Monday. At the surface, high
pressure will be building in Sunday, with breezy northwest winds as
the pressure gradient remains somewhat tight. This high centers
itself over the eastern CWA Sunday night into Monday. This should
set the stage for fairly cool lows during that time frame. Current
forecast does have some upper 40s sneaking into northern portions of
the CWA.
The upper ridge over the Rockies on Sunday eventually pushes
eastward into the High Plains/Northern Plains Monday night into
Tuesday, but gets dampened as shortwave energy tracks eastward
Tuesday/Tuesday night. With this shortwave does come a chance for
showers and thunderstorms, along with increasing instability. Upper
flow looks to transition to more northwesterly once again by
Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 606 PM CDT Fri Jul 14 2023
Terminals KABR,KATY,KPIR,KMBG
2-5sm vsbys are likely through the night due to low level smoke
over the area. Meanwhile sky cover will prove to be VFR through
the night. There is only a very slight chc for storms overnight.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TDK
SHORT TERM...KF
LONG TERM...TMT
AVIATION...TDK
Area Forecast Discussion
National Weather Service La Crosse WI
955 PM CDT Fri Jul 14 2023
.DISCUSSION...(This evening through Friday)
Issued at 234 PM CDT Fri Jul 14 2023
Key Messages:
- Wildfire smoke returns to the area.
- More storm chances into the evening.
- Periodic rain chances to continue well into next week.
Weekend Smoke and Air Quality:
GOES East Visible satellite imagery shows broad area of thick,
gray particulate matter (i.e., smoke) from southeast Minnesota and
western Wisconsin to smoke sources in western Canada. Upper level
water vapor imagery exhibits an upstream upper level ridge,
subsiding the thick smoke towards the surface. Resultant surface
observations from the Northern Plains into Montana exhibit
reduction in visibilities to 1-5 SM and haze/smoke in weather
sensor. Therefore, Air Quality Advisories have been issued for
Wisconsin and Minnesota from respective state`s DNRs where higher
confidence for advection from northwest to southeast through
Saturday. The respective Advisories highlight impacts to sensitive
groups in the "orange" category. Therefore, have continued
mention in weather grids through much of the weekend. While both
high resolution smoke models show reduction in surface PM 2.5
concentrations (~35 ug/m3) early Saturday morning, another
upstream punch above 60 ug/m3 possible through Saturday afternoon.
Something to keep an eye on if concentrations that increased do
make it to the surface.
Storm Chances and Setup For This Afternoon:
Similar mesoscale setup today as yesterday with moist low level
air mass in place with slightly drier air off the deck. Today`s
result has been decreased coverage in storms, comparatively, as
the drier air has reduced surface dewpoint temperatures from low
70s to mid to low 60s. The decrease in instability and increase in
inhibition evident in ACARS aircraft soundings at Minneapolis St
Paul Int`l Airport (KMSP) this morning into the early afternoon
with 200-400 J/kg MLCIN and only 25-75 J/kg SBCIN. Similar to
yesterday, minimal, nebulous surface convergence limiting any
forcing mechanism. With any auto convection extremely hampered by
the aforementioned drier air.
Initial showers along the Iowa/Minnesota border advecting from
west to east through the early afternoon initialized near
northwest Iowa in better convergence. As previously mentioned,
limited confidence for isolated to scattered storm potential early
this afternoon. Later this afternoon, better forcing, from a
perturbation evident in water vapor imagery reaching west central
Minnesota this afternoon, expected to advect through southeast
Minnesota into northeast Iowa and western Wisconsin.
Storm Chances Increasing This Evening, Cooler For Saturday:
Timing of forcing, reaching convective temperatures to overcome
aforementioned dry air & low level warm nose inversion, and
stabilizing of mid level lapse rates decrease strength of storms
as they advect in the area. While the plume of higher instability
(2000 J/kg) pushes into central Wisconsin, loss of diurnal heating
decreases instability along frontal forcing, 500-1000 J/kg, as it
reaches our northwestern periphery in southeast Minnesota. Not
expected to access the 0-1km shear of 20 knots, which is the same
as 0-3km shear, given elevated nature of storms. Given the low
level dry air, strong wind gusts most possible hazard, but again,
limited chances for stronger storms. Given low shear, single cells
bunching along the frontal boundary and dissipating strength with
southeasterly advection, initially around near 7pm along our
northwestern periphery of Dodge to Buffalo counties.
Slightly cooler temperatures expected for Saturday as the low
level cold front and upper level trough axis passes over the
forecast area. Other than the increased Haze and Smoke
probabilities, have continued slight storm and rain chances with
minute low to mid level instability and daytime mixing.
Saturday night through Monday...
The upper level currently near Hudsons Bay is forecast to sink
south toward the northern Great Lakes over the weekend with the
14.00Z ECMWF suggesting it could sink a little farther south
across the Upper Midwest. Either way, short wave troughs will
continue to rotate around the upper level low and swing over the
region to provide some forcing for additional shower and storm
development. The most widespread coverage continues to look to be
off the east of the local area with the main baroclinic zone
extending from the Eastern Great Lakes south through the Ohio
River Valley. Without a discernible boundary to help focus
development over the local region, expect any showers and storms
that develop to remain scattered in coverage. The exception to
this may be on Sunday if the farther south solution of the ECMWF
comes to fruition there could be more widespread coverage of
showers and storms. In this overall pattern, the instability looks
to be pretty minimal leading to an overall very low severe
weather threat.
Tuesday into Thursday...
Weak upper level ridging is still expected to be over the Midwest
Tuesday between the departing upper level low over the Great
Lakes and the next incoming system across southern Canada. With
the ridge look fairly flat, this next system will not take long to
bring the rain chances back to the area. Short wave troughs from
this low look to start bringing in some forcing Tuesday night with
the upper level low itself then tracking across the Upper Midwest
Wednesday into Thursday, although in a weakening trend as it
becomes an open wave. Again, not a lot of instability is expected
to be in place with just enough to support general thunder at
times.
Temperatures through next week look to remain seasonable with
highs in the 70s and 80s. No heat waves are suggested with
extremely low probabilities of reaching 90 degrees from the Grand
Ensemble data.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 955 PM CDT Fri Jul 14 2023
VFR conditions are expected through mid-morning with sct high clouds
and light winds expected. Both the HRRR and RAP vertically
integrated smoke fields have a signal for increased surface smoke
coming in during the mid-morning which given 5-6SM visibilities in
the Dakotas seen from this airmass today, will possibly see MVFR
visibilities throughout much of the day Saturday. Winds will
increase slightly from the west/northwest at RST to 10-15 knots with
gusts to as much as 20 knots. Some short-range guidance wants to
have some slight indication for a couple showers and storms tomorrow
afternoon associated with a weak shortwave but confidence is low as
to if this will occur. Visibilities should improve to VFR as surface
smoke concentrations improve late tomorrow.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...04/JAR
AVIATION.....Naylor
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
948 PM CDT Fri Jul 14 2023
.UPDATE...
Issued at 935 PM CDT Fri Jul 14 2023
Isolated convection continues ahead of a southward propagating
cold front. The convection extends from around Glasgow MT to
Sidney MT. and near Sather Dam in McKenzie county. Convection is
weakening and may or may not hold together long enough to reach
Grassy Butte. East of here there is one isolated cell just west of
Beulah Bay Rec area, but with no lightning associated with this
cell. Farther north, showers were dropping south from Saskatchewan
and Manitiba into Renville and Bottineau counties and will result
in mostly trace amounts as it slided into McHenry, Rolette and
Pierce counties.
We extended the chance for isolated shower/thunderstorm activity
through midnight. Otherwise no changes were needed with the
evening update. Areas of smoke remain with visibilities varying
quite a bit both north and south of the cold front.
UPDATE Issued at 632 PM CDT Fri Jul 14 2023
Isolated showers and thunderstorms continue to scoot southeast,
and are now mostly out of the forecast area. We did have a cell
collapse over Rugby with a gust to 46 knots, due mostly due to the
cell movement which was southeast around 40 mph. These showers
and storms have exited the area. Look for gusty winds to diminish
this evening. Smoke is expected to longer over the area tonight.
&&
.SHORT TERM...(This Evening through Saturday night)
Issued at 255 PM CDT Fri Jul 14 2023
Look for smoke and isolated thunderstorms through tonight, with a
brief break in the smoke during the day tomorrow. Main concern
today has been widespread wildfire smoke from Canada now in place
across much of the CWA. Look for visibilities generally down to 3
miles or slightly less at times. HRRR Smoke still improves
conditions from northeast to southwest tonight into Saturday
morning. Meanwhile, weak instability from daytime heating is
starting to bring a few areas of cumulus clouds. A secondary front
will push south through tonight and may bring with it an isolated
shower or thunderstorm. There is some surface CAPE of around 1000
j/kg currently, although this cape decreases as the evening
progresses. Shear is fairly low this evening. Thus severe weather
is not expected and any thunderstorm that can develop will overall
be more of the pulse type thunderstorms that may be strong briefly
yet not severe. Thunderstorms should then diminish around or
shortly after midnight. Breezy winds will also diminish tonight.
Look for overnight lows in the 50s, with some upper 40s in the
north.
Weak post frontal conditions will be found on Saturday. Look for
breezy northwest winds to return. Temperatures will be slightly
cooler and generally in the 70s. HRRR smoke showing wildfire smoke
stays limited through the day Saturday. This model then shows
smoke increasing across the west Saturday evening through the
night. Have added this in based on the HRRR trends. Chances for
showers and thunderstorms on Saturday through Saturday night will
be limited based on dry conditions and an overall lack of
instability.
.LONG TERM...(Sunday through Friday)
Issued at 255 PM CDT Fri Jul 14 2023
Look for breezy and dry conditions through Monday, with chances
for showers and thunderstorms returning at least through mid week.
A dry northwest flow pattern looks to continue for Sunday,
weakening somewhat on Monday. Smoke could linger during this time
period, although confidence is not high enough to place in the
forecast at this time. Breezy winds will be found Sunday, then
diminishing and changing directions on Monday. Temperatures will
remain below normal each day, although may slightly warm on
Monday. Of note are still somewhat low EFI values for min temps
Sunday night into Monday morning. Current forecast lows are still
in the mid to upper 40s with some 50s. Anything cooler may
approach some record lows for some areas. Ridge breaks down Monday
night which may return a chance of showers and thunderstorms.
CSU-MLP highlighting the west for perhaps an isolated stronger
storm during this time period which may warrant monitoring.
Tuesday through Wednesday could see an upper level wave move
through with the ridge breaking down. This could bring some
chances for showers and thunderstorms. CSU- MLP also showing
Tuesday may see a stronger storm as a result. Temperatures look to
warm slightly during this time period, perhaps returning to near
normal. Through the end of the week deterministic models hinting
at a ridge building back into the region. How far east it builds
will determine the overall pattern. For now it at least appears
near normal temperatures will remain with limited chances for
precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 935 PM CDT Fri Jul 14 2023
Wildfire smoke will bring areas of MVFR visibilities through this
evening. Smoke may improve late tonight into Saturday morning,
but may return again later Saturday. Otherwise, look for dry
conditions into Saturday. Breezy northwest winds will diminish
this evening, then pick up again Saturday afternoon.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...TWH
SHORT TERM...Anglin
LONG TERM...Anglin
AVIATION...TWH
Area Forecast Discussion
National Weather Service Denver/Boulder CO
823 PM MDT Fri Jul 14 2023
.UPDATE...
Issued at 808 PM MDT Fri Jul 14 2023
Radar shows a few showers and a couple of storms across the
northern half of the CWA this evening. A couple of outflow
boundaries are slowly working towards the metro that may be enough
to produce a couple of additional weak showers, but it appears the
storm threat has diminished for the metro this evening. Have made
some minor tweaks to the grids, most notably refining the PoPs
through 12z, but little else needed changes.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 241 PM MDT Fri Jul 14 2023
This afternoon and evening, an increasing northwesterly flow
aloft will develop over northeast CO as upper level winds increase
to around 70 kts stretching along the northern border. In Denver
the airmass still looks too capped at least through this afternoon
to support thunderstorms, with an inversion still in place in the
700-750 mb layer. SPC surface analysis shows the highest MUCAPE
of 1000 j/kg is along the northern border. This coupled with the
closer proximity of the upper level jet, may be enough to produce
one to two strong/severe storms over the northeast plains late
this afternoon and evening. Storms were starting to develop along
the Cheyenne Ridge this afternoon, and the HRRR shows this
expanding and moving southeast across eastern Weld, Morgan, Logan
and Washington counties through this evening. Wind gusts in excess
of 60 mph and hail up to 1.5 inches in diameter possible of these
storms are able to crank up. Elsewhere across the forecast area,
elevated showers/storms may develop and drift eastward, and
outflow boundaries combined with the increasing flow aloft may
help initiate storms this evening. Some showers, maybe a few
storms could linger overnight but they will be weaker.
On Saturday, a cooler day in store with good moisture. The flow
aloft will remain northwest with upper level winds around 60 kts
at 250 mb. RAP forecast soundings indicate sufficient instability
by late in the afternoon to support thunderstorms. MLCAPE values
in the 1400 and 1800j/kg at Denver and Akron respectively. Higher
precipitable water values as well, 1 to 1.1 inch. Isolated
strong/severe storms possible in the afternoon similar to today.
.LONG TERM...(Saturday night through Friday)
Issued at 241 PM MDT Fri Jul 14 2023
Upper level high centered along the California/Nevada border will
slowly drift east-southeast Sunday and through the early part of
next week. Isolated/scattered showers and thunderstorms expected
to continue into the evening hours across the Front Range and
eastern plains. Air aloft will be warming and drying Saturday
night. This will lead to decreasing chances for convection through
Saturday evening with convection ending by midnight.
Temperatures jump about 10 degrees Sunday with most locations
reaching the lower 90s across northeast Colorado. For Monday,
temperatures increase more with highs expected to reach the upper
90s over northeast Colorado. The usual warm locations could top
100 degrees. May need a Heat Advisory for Monday with these very
warm temperatures. Come Tuesday, the high will be centered over
New Mexico with a westerly flow aloft over Colorado. Expect to see
an increase in winds over the higher terrain because of this. Mid
and upper level moisture also increases, which should result in
isolated to scattered high based showers and thunderstorms late
Tuesday afternoon and evening.
For Wednesday through Friday, will see a little relief from the
heat with highs close to normal (90F). Enough moisture returns to
the area for afternoon showers and thunderstorms each day. The GFS
and ECMWF both show a wave and a good amount of convection for
Thursday. This is nearly a week away, so confidence in timing is
still low, but there should be a day late next week for a good
chance of showers and thunderstorms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 533 PM MDT Fri Jul 14 2023
Generally VFR conditions with light winds over the TAF period.
Still a slight chance of a passing shower or storm near DEN this
evening between 02-05z but guidance isn`t sold on this. Otherwise
northeast winds will eventually give way to drainage flow
overnight. Additional chance at TS/SHRA tomorrow afternoon and
evening but coverage doesn`t look widespread enough to include any
sort of TEMPO/PROB30 group. Main concern with any convection would
be gusty outflow winds.
&&
.FIRE WEATHER...
Issued at 241 PM MDT Fri Jul 14 2023
On Saturday, marginal conditions will persist in the valleys of
Grand, Summit and Park counties, but more limited area and time.
Elsewhere, no critical conditions are expected. Relative
humidities in those areas will drop into the teens in the
afternoon.
High pressure aloft will bring warmer and drier conditions
through Monday. Tuesday will remain very warm, but increasing mid
and upper level moisture will bring a chance for high based
showers and thunderstorms. Gusty winds will be the main concern
with this activity. Winds during the afternoons will be gusty in
places. The windiest day looks to be Tuesday with gusts of 35 mph
possible.
&&
.HYDROLOGY...
Issued at 241 PM MDT Fri Jul 14 2023
The threat of flash flooding will be limited and focused
primarily on the Cameron Peak burn scar through early this
evening, and again Saturday afternoon and early evening.
Showers and thunderstorms will be decreasing and end Saturday
evening. This activity is expected across the Urban Corridor and
eastern plains, brief heavy rain could produce minor flooding of
low lying areas. For the burn areas, dry conditions are expected
through Monday, and the activity on Tuesday is expected to be
weak. A better chance for showers and thunderstorms returns to the
area Wednesday which may bring a flash flooding threat to the
burn areas.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Hiris
SHORT TERM...Cooper
LONG TERM...Meier
AVIATION...Hiris
FIRE WEATHER...CoopMeier
HYDROLOGY...CoopMeier
Area Forecast Discussion
National Weather Service Billings MT
349 PM MDT Fri Jul 14 2023
.DISCUSSION...
Through Sunday night...
The Northern Rockies region is under northwesterly aloft, between
an upper ridge centered from WA to CA, and an upper trough to the
east. This pattern typically produces an unstable atmosphere for
us, and model soundings suggest that this is indeed the case. In
fact, isolated showers and thunderstorms have already developed
over central and southeast MT. These showers/storms will move
southeastward through this evening and could reach more of south
central MT and north central WY. They could produce a few wind
gusts to 30-40 mph or so but think that the lack of moisture
aloft should limit wind potential. The chance of showers/storms
through this evening is 20-30%. Any showers/storms should diminish
overnight with the loss of instability.
Saturday looks similar to today, with isolated showers and
thunderstorms in the afternoon (20% chance). It will be breezy in
southeast MT with northwesterly winds gusting to about 30 mph from
late morning through the afternoon.
Sunday looks dry as the upper ridge moves farther eastward, over
the Northern Rockies.
Smoke: smoke from Canadian wildfires will continue to move
south/southwestward into south central-southeast MT and north
central WY through Saturday morning. HRRR model suggests that it
retreats somewhat near Livingston during the day Saturday while
the rest of the area continues to experience smoky conditions.
Smoke then looks to expand southwestward again to Livingston
Saturday night. Mid-level winds should turn more west/southwesterly
on Sunday, which should help to decrease smoke concentrations in
our area. Get the latest air quality conditions from the MT
Department of Environmental Quality (DEQ) and WY DEQ.
Low temperatures will generally be in the 50s to middle 60s
tonight through Sunday night. High temperatures will be in the 80s
Saturday and 80s to 90s Sunday. RMS
Monday through Friday...
The upper level trough axis will move over the region Monday,
giving way to westerly flow. Additionally, southeasterly surface
winds will transport moisture into the region. Late Monday, a cold
front will move through from a low moving across southern Canada,
bringing a chance (15-30%) for showers and thunderstorms. Pockets
of heavy rain will be possible in storms. Tuesday through the rest
of the extended, another ridging pattern will build in, limiting
precipitation chances (5-15%) to the mountains and foothills and
the far southeastern corner of Montana.
Monday is expected to be the warmest day, with high temperatures
in the mid to upper 90s. Coupled with the increasing moisture,
heat indices will be increased. Individuals sensitive to heat,
especially those without effective coolings and/or adequate
hydration, should take precautions Monday. Behind the cold front,
temps will drop slightly for Tuesday through Thursday, with highs
in the mids to upper 80s. By Friday, highs will return to the 90s.
Archer
&&
.AVIATION...
Wind gusts near 25 kts will continue until this evening from KSHR
east. Smoke will continue to move in, affecting visibility from KBIL
to KSHR and east. Isolated showers and thunderstorms are possible
until the evening. Archer
&&
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
-----------------------------------------------------------
BIL 059/087 060/092 062/094 062/088 057/084 059/087 060/093
22/T 00/U 00/B 10/U 00/U 00/U 10/U
LVM 052/086 054/092 057/094 055/085 051/084 051/086 054/091
00/K 00/U 01/B 10/U 00/U 00/U 01/U
HDN 056/087 057/092 061/096 061/089 056/085 055/088 059/094
22/T 00/U 00/B 10/U 00/U 00/U 10/U
MLS 059/084 060/087 061/093 064/088 059/083 056/085 060/092
22/T 00/U 00/B 20/U 00/U 00/U 10/U
4BQ 059/084 059/089 060/094 065/088 060/084 055/086 059/091
22/T 00/U 00/B 20/U 10/U 00/U 10/U
BHK 054/080 055/083 054/086 059/087 055/082 052/082 055/089
20/K 00/U 00/N 30/U 10/U 00/U 10/U
SHR 054/084 055/089 058/095 062/086 054/082 052/085 056/089
12/T 00/U 00/B 10/U 10/U 11/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Charleston SC
1056 PM EDT Fri Jul 14 2023
.SYNOPSIS...
The region will remain along the western fringes of Atlantic
high pressure through next week. A surface trough will persist
inland through the weekend.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Late this evening, SPC Mesoscale Analysis indicated the MLCIN
across the SC Lowcountry, with 25-50 J/kg. However, SE GA
remained generally free of CIN of 15 J/kg or more. KCLX detected
a small cluster of showers drifting over portions of Tattnall
and Long Counties. These showers may continue to drift over the
area through midnight. However, recent runs of the HRRR
indicates that the convection will end shortly after midnight.
The updated forecast will feature adjustments to the hourly
PoP, Wx, and sky.
The rest of the night should feature dry and mild conditions,
with the exception of isolated showers offshore. Min
temperatures will once again fall into the mid 70s to near 80
degrees close to the coast and at Downtown Charleston.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Saturday: Broad mid/upper-level troughing will hold across the
Southeast States as the region remains pinned between Bermuda high
pressure centered well offshore and weak surface troughing across
the interior. Models show a modest shortwave crossing during peak
heating. The combination of forcing with this feature with broad
convergence in the vicinity of both the inland moving sea breeze and
inland trough will support scattered/numerous, mainly afternoon/
evening showers/tstms. A few strong to locally severe tstms could
occur where updrafts become enhanced near mesoscale boundary
collisions. Gusty winds and frequent cloud-to-ground lightning look
to be the primary hazards. Highs will warm into the lower 90s.
Dewpoints look to mix out in the lower 70s, pooling back into the
mid-upper 70s near/behind the sea breeze. Heat indices will peak
around 105 for many areas, but should hold below Heat Advisory
levels. Warm/humid conditions will linger overnight with lows mid
70s inland to the lower 80s at the beaches and Downtown Charleston.
Sunday: The synoptic pattern will be nearly identical to Saturday
with warm/moist conditions holding in place. The coverage of
showers/tstms may be a tad lower compared to Sunday with no real
discernible shortwaves progged to pass through the area and a
stronger westerly flow dominating. It will be a bit warmer with a
slight uptick in both low-level thicknesses and 850 hPa temperatures
noted. Highs will warm into the mid 90s for most areas away from the
beaches. Dewpoints will pool back into the lower-mid 70s with upper
70s expected closer to the coast. Heat indices will peak 104-108
with some localized spots hitting 110 or so. A Heat Advisory could
be needed for a few areas with later forecast cycles. Lows early
Monday will range from the mid 70s inland to the lower 80s at the
beaches and Downtown Charleston.
Monday: No major changes to the synoptic pattern are expected. A
persistent deep westerly flow will limit net moisture levels
somewhat with lower PWATs and 850 hPa theta-e values noted. This may
help curtail convection somewhat with the best chances for
showers/tstms occurring along to possibly behind the afternoon sea
breeze where moisture levels will be the highest. Highs will warm
into the lower-mid 90s with heat indices 100-105 inland to 105-110
roughly along/east of I-95.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Subtropical ridging will build across the Deep South into the
Southeast U.S. next week as the Bermuda high offshore also nudges
west. This should yield hot and drier conditions with rain chances
averaging below climatological normals for mid-July. For Wednesday
through Friday, highs will make a run for the century mark for
parts of the interior. Dewpoints will mix out each afternoon,
but pool near/behind the sea breeze. Heat indices could push 110
at times and Heat Advisories could be needed.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
0Z TAFs: Convection has drifted inland of the terminals this
evening. The rest of this evening and tonight, conditions should
remain VFR with light southwest winds. A mid-level disturbance
is timed to cross the CWA from west to east Saturday afternoon.
Showers and thunderstorms are forecast to develop ahead of the
disturbance and the sea breeze, especially near KSAV. The KSAV
TAF will feature a TEMPO from 20-24Z for MVFR conditions during
a TSRA. KCHS and KJZI could see some convection during the late
afternoon and evening, but coverage appears too low to highlight
in the TAFs.
Extended Aviation Outlook: Brief flight restrictions are expected
due to showers/thunderstorms each afternoon/evening. The highest
potential looks to be through Sunday.
&&
.MARINE...
Tonight: As high pressure persists offshore, southerly winds 10-15
kt will remain across the locals waters with seas 2 to 3 feet.
Saturday through Wednesday: There are major concerns. A south to
southwest wind regime will persist through the period with the
region located along the western periphery of Bermuda high pressure
centered well offshore. Winds may turn more westerly Monday, but a
general south to southwest flow will dominate with winds generally
15 kt or less. Seas will average 2-4 ft
Rip Currents: Lifeguards have been reporting 9-10 sec swells around
2 ft for much of today (Friday) with some rips already being
observed at Folly Beach and Isle of Palms. Since it is a weekend
with excellent weather and there may be a slight uptick in breaking
wave heights (2-3 ft) with 9-10 sec periods, the rip current risk
will be solidly in the moderate category. Breaking waves are
forecast to diminish a bit for Sunday, but 9-10 sec periods will
persist. Another moderate risk may be needed.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...NED
SHORT TERM...
LONG TERM...
AVIATION...NED
MARINE...BRM
Area Forecast Discussion
National Weather Service Cheyenne WY
526 PM MDT Fri Jul 14 2023
.SHORT TERM...(This evening through Saturday)
Issued at 227 PM MDT Fri Jul 14 2023
Latest GOES imagery has shown Cu development since early this
afternoon along much of the high terrain in the post frontal
environment with northerly surface flow. This has lead to
northerly upslope flow over the North Laramie Range along with a
convergence boundary developing downwind of the range near
Wheatland which has been the focal point for initial storms today.
Latest RAP has 1000- 1200 J/kg of MLCAPE along and in the
immediate foothills of the Laramie Range with 0-6 km shear of 40
kt. Most of that shear is unidirectional which will make storm
splits likely today with bunkers right mover motion to the
southeast at 30 kt. Have already seen active splits with the
initial cells in the North Laramie Range. Additional development
is ongoing along the South Laramie Range west of Cheyenne where
hi-res guidance places a few storms through early this evening.
SPC continues the marginal risk for severe storms this afternoon
mainly for the hail threat. While the environment is not as
favorable today as days past, could still see quarter size hail
with the strongest storms.
Headed into Saturday, 500mb height rises over the Great Basin will
lead to more northwest flow with a passing shortwave before the
ridge axis shifts more overhead near the end of the weekend. Latest
RAP has upwards of 1000 J/kg of MLCAPE extending from the South
Laramie Range east remaining south of the North Platte River valley.
Could see a few strong storms in Laramie and Kimball Co as well as
farther south along the CO Front Range. Temperatures will begin
their gradual warmup continuing through the weekend as Saturday
afternoon highs in the upper 70s and 80s.
Additionally, latest GOES Geocolor imagery shows an area of smoke
being transported south from the Canadian wildfires. This will lead
to poor air quality for portions of east-central WY through the
weekend and therefore and Air Quality Alert is in effect.
.LONG TERM...(Sunday through Thursday)
Issued at 440 AM MDT Fri Jul 14 2023
Overall, the long term forecast looks much warmer and drier through
the first half of the week. By the latter half, cooler temperatures
and increased storm chances look probable. Starting on Sunday, the
ridge over the desert southwest will strengthen and slowly push
eastward. By Sunday afternoon, a 600 decameter high will be
positioned over the Four Corners region with the ridge continuing to
push eastward. This will usher in much warmer and drier air to the
CWA. This strong ridge stays locked over the region until about
Tuesday, where it will weaken and flatten out into more zonal flow
aloft. During this time, temperatures will be on the hot side.
Sunday through Tuesday highs will likely range from the upper 80s to
mid 90s. Monday will likely be the hottest day of the week as 700 mb
temperatures make it up to +22C! This will lead to most cities in
the CWA having high temperatures in the 90s! The hot and dry weather
will keep most storms away, but cannot rule out an isolated
thunderstorm or two during the afternoon hours as weak vort maxes
pass through the ridge aloft.
By Wednesday, the upper-level ridge starts to build back up over the
Great Basin, putting the CWA into more northwesterly flow. This will
lead to cooler temperatures heading into the latter portion of the
week with high temperatures falling into the upper 70s to mid 80s by
Thursday. Northwest flow will also lead to increased storm chances
as the GFS shows a series of shortwaves moving across the CWA.
Afternoon, evening, and potentially nighttime convection could be
possible Wednesday through Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 521 PM MDT Fri Jul 14 2023
Wyoming TAFS...Northwest flow aloft will help produce a chance of
thunderstorms early this evening at Laramie and Cheyenne, with
storms at Cheyenne producing wind gusts to 35 knots, visibilities
near 4 miles and ceilings around 4500 feet AGL. Otherwise
scattered to broken clouds from 6000 to 10000 feet AGL will occur
this evening at all terminals, with skies then clearing. Winds
will gust up to 32 knots until 02Z.
Nebraska TAFS...Northwest flow aloft will help produce
thunderstorms in the vicinity at Scottsbluff and Sidney early this
evening. Scattered to broken clouds from 7000 to 9000 feet AGL
will occur through early evening, then skies will clear. Wind
gusts to 25 knots will prevail at Scottsbluff and Sidney until
02Z.
&&
.FIRE WEATHER...
Issued at 227 PM MDT Fri Jul 14 2023
Frontal boundary lays across across north central
Colorado...north along the west slopes of Laramie Range into
northern Carbon County. East of this front...humidity has been
above critical levels with widely scattered storms developing and
moving eastward. West of the front...afternoon humidity near
critical with wind gusts to 30 and 35 mph across Carbon County.
Fuels are still reported not ready...so afternoon fire weather
concerns are minimal. Similar conditions Saturday with afternoon
storms east and low humidity and gusty winds west. Warmer...dry
and breezy Sunday into Monday across southeast Wyoming as high
pressure builds further north and east.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MB
LONG TERM...SF
AVIATION...RUBIN
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Grand Forks ND
1025 PM CDT Fri Jul 14 2023
.UPDATE...
Issued at 1017 PM CDT Fri Jul 14 2023
Surface stabilization is occurring with loss of daytime heating.
This has caused cluster of thunderstorms to weaken, with very
little chance of gusty winds as area of showers continues into
Minnesota.
For the rest of tonight, dry conditions are anticipated. There may
be some patchy fog tonight for those who saw rainfall this
afternoon/evening. But clouds moving in from the north should help
fog dissipate tonight as well.
UPDATE Issued at 717 PM CDT Fri Jul 14 2023
A cluster of low topped thunderstorms are moving quickly through
the Devils Lake basin southeast at around 50 mph attached to a
frontal boundary moving through the area from the north. Given
steep low level lapse rates, the momentum of downburst winds are
producing observed 30-55 mph wind gusts, despite weak
instability. This will remain possible through 9 PM within the
eastern Devils Lake basin into central Red River Valley before the
low levels stabilize around sunset with the loss of daytime
heating.
Additional showers and thunderstorms elsewhere appears to be
unlikely given lack of better forcing, instability, and moisture.
Thick smoke aloft continues to stream into the area through the
remainder of the day into tonight. Smoke at the surface is being
observed. Guidance indicates this will be the case into tonight.
The frontal boundary will help push surface smoke out of the area
tonight, at least periodically. Guidance does indicate that
daytime mixing tomorrow may help bring smoke to the surface within
North Dakota again in the afternoon.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 236 PM CDT Fri Jul 14 2023
Smoke and precipitation chances remain the main impacts for the
period.
Satellite loops show some thinning of the smoke across our
northern counties, but another surge from Canada is already
coming in near the Turtle mountains. There is some cumulus
developing just ahead of the leading edge of the smoke, along with
some near the cold front moving through southeastern Saskatchewan
and southwestern Manitoba. With the cu developing, still can`t
rule out a few showers and maybe a thunderstorm. Even MU CAPE is
less than 500 J/kg in our north, so not expecting any severe
impacts but a few spots could see some light rain. Most of the
activity should taper off after sunset, although a few of the CAMs
still have some post frontal showers lingering until tomorrow
morning.
The cold front coming down tonight should bring some mixing of
smoke down to the surface for a while longer, looking at satellite
loops and obs with haze upstream. The RAP and HRRR both have some
decrease in smoke concentration at least for the near surface
levels in northwestern MN and far northeastern ND on Saturday.
This would fit with the Canadian upper low over Ontario/Manitoba
digging south and high pressure building in behind the frontal
boundary tomorrow. Think at this point that most of the low level
smoke will be shunted to the south and west, so will leave the
mention out for Saturday. Still, can`t rule out some higher level
smoke still coming down the northwesterly flow aloft, so continued
to put the floor of sky cover at 30 percent for tomorrow. Saturday
night, the upper low will dig down towards northern MN and there
could be some showers and thunderstorms near Lake of the Woods. MU
CAPE still looks pretty minimal, so not expecting any severe
impacts.
.LONG TERM...(Sunday through Friday)
Issued at 236 PM CDT Fri Jul 14 2023
Northwest flow aloft will be the main feature to start the period as
the upper level low begins to retrograde southwest from the Hudson
Bay region. Expect some impulses to propagate through the flow which
will increase rain chances in the northern zones, especially near
the Lake of the Woods region of Minnesota.
By Tuesday, the low finally begins to push east as a vigorous short
wave transits the ridge axis flattening it out a bit. Surface high
pressure remains in control and expect southerly winds in return
flow ahead of another low pressure system entering the High Plains.
The return flow will help increase low level moisture ahead of the
system and sufficient dynamics will be in place to help trigger
showers and storms across the region. As the system exits across the
Great Lakes, the upper ridge maintains its relative strength keeping
high temperatures in the upper 70s to low 80s through the end of the
period. Otherwise, as upper level disturbances propagate through the
flow, precipitation chances continue through the end of the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 717 PM CDT Fri Jul 14 2023
VFR conditions are forecast throughout the TAF period. Winds this
evening into the morning through 15 UTC are forecast to remain
light out of the northwest, under 10 kt. The exception lies within
isolated thunderstorms within the Devils Lake basin into central
Red River Valley before 02 UTC, where gusty winds 30-45 kt and
lowered CIGs and vsby are likely. Currently, KDVL is the only site
expected to see these conditions.
Thick smoke aloft will remain over the region through tonight into
Saturday. There is a medium to high chance for smoke at the
surface reducing vsby as low as 3SM within North Dakota through 10
UTC, with smoke remaining aloft thereafter during the day
Saturday.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...CJ
SHORT TERM...JR
LONG TERM...Hopkins
AVIATION...CJ
Area Forecast Discussion
National Weather Service Glasgow MT
854 PM MDT Fri Jul 14 2023
.DISCUSSION...
EVENING UPDATE:
Showers and thunderstorms this evening continue to move southeast.
Blended in ConsShort guidance as it is having the best grasp of
said showers. A prominent outflow boundary has generally moved to
the south/southeast, at times mixing down winds up to 55 mph at
the surface. These showers continue to weaken, but an occasional
gust above 35 mph remains possible (10-30% chance). Overnight,
winds across the entire CWA will subside. Thus, removing the Lake
Wind Advisory.
Smoke continues to advect into the CWA, bringing visibilities down
to 2 to 4 miles for much of the evening. The remainder of the
forecast as below still remains valid.
-Enriquez
PREVIOUS FORECAST:
Besides developments with regard to smoke
concerns this weekend, minimal forecast changes were needed. The
boundary layer winds and latest projections from the HRRR and RAP
smoke models show waves of smoke continuing through at least
Sunday morning, with dense smoke and unhealthy air quality at
times. Visibility has already dropped to 2 miles for locations
such as Glasgow and Wolf Point and there is medium chance for at
least this much reduction to occur again by Saturday morning.
Current and forecasted smoke concentration over higher terrain
toward central Montana is relatively better, so went ahead with a
Dense Smoke Advisory through 6pm Saturday that excludes Petroleum
and SW Phillips counties for now. Otherwise, breezy afternoon
conditions continue to a lesser degree Saturday with isolated
thunderstorms again southwest of Fort Peck Lake. After a frontal
system Monday night brings elevated winds and thunderstorm
chances, a significant ridge looks likely to begin building in by
the weekend presenting some heat concerns.
-Zanker
&&
.AVIATION...
UPDATE: 0250Z
FLIGHT CAT: VFR - IFR
DISCUSSION: Isolated afternoon thunderstorms continue to move
southeastward. They will continue to diminish for the next few
hours, but SMOKE and HAZE will keep the sky obscured with MVFR
visibility common through the TAF period. There is a medium chance
for IFR visibility in smoke at times, particularly Saturday
morning.
WIND: In the vicinity of showers, winds could gust as high as 40
to 45 kts, but overall, the winds will continue to diminish
tonight. In the morning, winds will pick back up from the
northwest, at 10-20 kt, gusting to 25 kts at times.
-Enriquez
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Dense Smoke Advisory until 6 PM MDT Saturday for Central and
Southeast Phillips...Central and Southern Valley...Daniels...
Dawson...Eastern Roosevelt...Garfield...McCone...Northern
Phillips...Northern Valley...Prairie...Richland...Sheridan...
Western Roosevelt...Wibaux.
&&
$$
weather.gov/glasgow
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
644 PM CDT Fri Jul 14 2023
.UPDATE...
Issued at 624 PM CDT Fri Jul 14 2023
With the daytime thunderstorms having moved well out of the area
this afternoon and evening, we are expecting a quiet night with
overnight lows in the upper 50s and low 60s. Winds will be
northwesterly Saturday and both the RAP Smoke and HRRR Smoke
models both bring in at least haze (if not smoke) from the
Canadian wildfires tomorrow. With this and observations in much of
eastern Montana and the Dakotas already below 3 miles visibility
due to smoke/haze, I incorporated haze into the forecast through
Saturday.
&&
...Aviation Update...
.DISCUSSION...(This evening through Friday)
Issued at 415 PM CDT Fri Jul 14 2023
Key Messages:
* Last of the thunderstorms exits by early evening, leaving dry
and fairly pleasant conditions for tonight and Saturday.
* Next chance for thunderstorms arrives Saturday night into
Sunday. Marginal risk for severe weather.
* Hot and humid conditions return for at least southern half of
the forecast area for first half of new work week.
* Messy pattern with nearly daily, off and on thunderstorm chances
Tuesday through Thursday.
Forecast Details:
After a busy morning and early afternoon, much quieter conditions
should prevail this evening and continue tonight into Saturday.
The true cold front still has some ways to go to fully work
through the CWA as its currently depicted by line of agitated CU
from near LXN to N of GRI. Strong mid to upper level subsidence,
weak lapse rates, and fairly weak convergence should preclude much
more than a few sprinkles. Can see a few towers trying to go up
from the office but they quickly run out of steam as they grow
into the weak mid level lapse rates. Winds will shift to the NW
with the frontal passage and eventually some drier air should work
in as well. Can`t completely rule out some patchy ground fog
tonight as winds die down, but counting on the dry air advection
to preclude more than a very minor/iso issue. Lows tonight will be
comfortable in the upper 50s to lower 60s.
NWrly winds continue into Sat, which along with seasonably low
Tds in the mid to upper 50s, should lead to comfortably warm
conditions for the aftn as highs climb into the mid 80s to near
90F. A great mid-July day that fortunately falls on the weekend!
The 18Z HRRR tries to spark one or two storms in the far W late
Sat aftn into eve, but this had poor support from other HREF
members so no mention in the grids attm.
Models suggest the next chc for organized shwrs/tstms will come
late Sat night into Sun AM in response to quick-moving upper level
shortwave and associated low to mid level warm air advection and
30-35kt LLJ. SREF suggests MUCAPE values of 1000-2000 J/kg will
advect into at least far W/SW zones by daybreak, but keeps
effective shear on the lower end at only about 30kt. NAM forecast
soundings suggest some potential for higher values, again at least
in our W, so we`ll need to monitor potential for marginally
severe hailers Sun AM. Tstms chcs for remainder of the day will
really depend on timing of the shortwave - slower arrival, better
potential for instability to build and some strong storms. Faster
shortwave would move it through mostly during the AM and probably
more subsidence and lesser instability for the aftn hrs. Overall,
confidence on details even by Sun are still pretty low. Areas S of
morning storms could heat up into low to mid 90s for the aftn,
particularly S of state line, with central and northern zones
mostly in the upper 80s.
Not much time spent on the extended forecast due to active
conditions today, but general pattern suggests more of the same -
off and on tstms with frequent shortwaves within zonal to NW upper
flow. This pattern will likely keep the really hot temps shunted
mostly S of our Neb. zones, but KS zones could see daily highs
climb into mid to upper 50s. Will really just depend on timing and
placement of waves that are next to impossible to pin down in
days 3-7. Where air temps do warm into the upper 90s, the presence
of abundant low level moisture aided by near-peak
evapotranspiration could yield peak heat index values in the low
to mid 100s in the Mon to Wed time frame.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 624 PM CDT Fri Jul 14 2023
VFR conditions are expected through the TAF period. Winds will be
out of the northwest, light overnight then increasing to 9-12 kts
during the day Saturday. Skies are expected to be mostly
clear...but smoke from Canadian wildfires may make skies hazy
during the day Saturday. Incorporated haze into KGRI for Saturday
afternoon and evening based on upstream observations and the RAP
Smoke model. Left HZ out of KEAR for now as I believe it will be
less impactful there, but still possible. Not currently
anticipating major reductions in surface visibility, but slant-
range visibility may be impacted at KGRI Saturday afternoon and
evening.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...Hickford
DISCUSSION...Thies
AVIATION...Hickford
Area Forecast Discussion
National Weather Service Goodland KS
544 PM MDT Fri Jul 14 2023
.SHORT TERM...(This evening through Sunday night)
Issued at 230 PM MDT Fri Jul 14 2023
Across the cwa this afternoon, skies are mainly sunny except over
central portions of the area where low/mid clouds linger from
remnants of rw/trw over the past couple hours. A front has push
through the region, allowing for northerly flow area-wide, with
gusts 25-35 mph at times. Temperatures have dropped into the 70s as
well, with dewpts in the mid 50s to mid 60s.
For the remainder of the afternoon into tonight, with morning
precip/clouds having cleared the area for the most part, the wx
focus shifts to the potential for activity working southeast of the
central Rockies, in tandem with a weak shortwave coming down along
the east side of a broad upper ridge. CAMs(Convective Allowing
Models) are mixed as to how much activity the area will see this
evening. Currently, activity is starting to crop up over Wyoming,
and will move southeast towards the cwa over the next couple hours.
the area still has a Marginal risk for severe storms this evening.
The area has stabilized some with the frontal passage, but the HRRR
is showing some weak MUCape/DCape. Some convection is possible, but
not looking for much.
Looking for patchy fog to develop towards sunrise across the area.
Light/variable winds with a ridge axis over the area, combined with
ample low level moisture, should allow for some patchy fog to
develop for a couple hours.
Going into the upcoming weekend, amplified upper ridge over the
western portion of the country will shift slightly east into the
Rockies by Sunday, reinforcing the northwest, downslope flow aloft.
High pressure east of the cwa with low pressure forming over to the
west will create southerly flow allowing for moisture to funnel over
the western cwa. This will interact with another shortwave late in
the day to trigger rw/trw with the focus mainly along/west of
Highway 25. This activity may shift slowly east overnight before
tapering off. Not looking for any severe storms at this time.
For Sunday, northwest aloft, combined with south-southwest surface
flow, will allow for a warmer day that expected for Saturday.
Another shortwave set to move over the far eastern locales will
interact with a front along the KS/NE state line. With best
instability east, there could be a few strong to severe storms
along/east of Highway 83. Hail, wind and heavy rain hazards in play.
Most activity will cease by 06z Monday.
For temps, the first half of the weekend will have highs in the 80s
area-wide, give way to the lower and mid 90s for Sunday. Heat
indices for Sunday will range near to just above forecasted highs.
Overnight lows tonight/Sunday night will have upper 50s west to the
mid 60s east. For Monday night, 60s are expected.
.LONG TERM...(Monday through Friday)
Issued at 203 PM MDT Fri Jul14 2023
Ridging will be present over the plains to start the period. This
will allow temperatures to rise into the middle to upper 90s with
some spotty triple digits across east Colorado. A dryline will be
setup near the KS/CO line, locales on the dry side of the
aforementioned boundary will be the warmer air temperature wise vs
on the more moist side temperatures won`t be as warm but heat
indices will be near or above the triple digits.
Starting Tuesday, the ridge begins to break down in more zonal/NW
flow which will allow the forecast area to be susceptible to
waves and disturbances, similar to the pattern that we have been
in lately. Tuesday through the remainder of the work week will
have the potential for daily shower and storm chances. Guidance is
hinting at a more pronounced wave moving into the area Thursday
which would have the potential for more widespread precipitation
chances. Will leave the pops at high end chance for now vs the
likely pops that the NBM loaded in as any little shift with this
disturbance would make or break the rain chances. Wind shear and
CAPE does increase Tuesday onward which would again favor severe
storm chances.
The humid conditions will return after Monday as PWAT values rise
back into the 1.1 to 1.4 range with Thursday as PWATS rise to the
1.4-.7 across the area. DDC sounding climatology does show this as
above the 90th percentile for this time of the year. As mentioned
above Thursday does have the potential for a more widespread rain
potential if the current wave remains on track so will need to
monitor this for excessive rain potential.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 543 PM MDT Fri Jul 14 2023
VFR conditions forecast for the TAFs. Light and variable winds
are expected as the surface high pressure moves through tonight.
Low confidence of any fog forming due to dry air advection moving
in overnight.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JN
LONG TERM...Trigg
AVIATION...JTL
Area Forecast Discussion
National Weather Service Green Bay WI
1103 PM CDT Fri Jul 14 2023
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Saturday
Issued at 229 PM CDT Fri Jul 14 2023
The latest RAP analysis and satellite/radar imagery show flattened
troughing across the northern Mississippi Valley and northern
Great Lakes early this afternoon. A surface trough extends south
across Minnesota with showers over southern MN and Iowa within the
right rear quad of a jet streak. RAP soundings show quite a bit
of dry air in the column at 18z with precipitable water values
right around normal for the date. As a result, diurnal cumulus
clouds have been relatively shallow so far today. As the surface
trough moves east, thunderstorm potential is the main forecast
concern.
Tonight...The surface trough over the northern Mississippi Valley
is expected to sharpen and track east across Wisconsin. With help
from a weak shortwave impulse and possibly an upper jet streak,
thunderstorms remain expected to develop late this afternoon or
early this evening over far western WI and eastern MN within a
region of 600-1000 j/kg of ML CAPE. These thunderstorms are
expected to move east into north-central WI by mid-evening and
into northeast WI by late evening before exiting overnight.
While instability will gradually weaken through the night,
effective shear of 30-35 kts could lead to enhanced updrafts and a
few strong storms that could produce gusty winds in excess of 40
kts and hail. Potential for strong storms seem highs over north-
central and central WI by mid- evening before instability wanes.
After the storms exit, patchy ground fog will be possible where
rain occurs.
Saturday...With thunderstorms exiting overnight, slight height
falls will be occurring aloft with weak cold advection in the low
levels. In general, models are unenthusiastic about thunderstorm
chances during peak heating, but are hinting at isolated
development over northeast WI along lake breezes where a couple
hundred cape is expected.
Unfortunately, both the HRRR and RAP are suggesting another round
of impactful smoke will push across the region on Saturday.
Upstream observations over the Dakotas suggest reduced
visibilities at the surface from smoke. Besides creating unhealthy
air, it`s quite possible that smoke will be thick enough to reduce
insolation which will hinder storm development. Lowered high temps
by 2 degrees compared to the NationalBlend, and that may not be
nearly enough.
.LONG TERM...Saturday Night Through Friday
Issued at 229 PM CDT Fri Jul 14 2023
Unsettled weather continues for the weekend with a few additional
showers and rumbles of thunder Saturday night and Sunday. Quieter
conditions then return for early next week before the next cold
front moves towards the region in the middle of the week.
The weekend...
Active weather will be on its way out of the region in the early
portions of the extended period Saturday night, bringing back
quieter conditions for most of the region for early Sunday as
instability decreases. Sunday will then see another repeat of
Friday and Saturday, with quiet morning conditions giving way to
active weather later in the afternoon and evening as a weak cold
front drops into the region. Much like the days preceding it,
instability will be fairly sparse ahead of any showers, so while
thunder is possible, stronger or severe weather are not expected
at this time. High temperatures on Sunday will range from the
lower 70s to the lower 80s.
Rest of the forecast...
After the rain Sunday, cooler air will be in the area for Monday
with high temperatures dipping into the upper 60s to upper 70s
across the area. Drier conditions will also be on their way into
the region for Monday and Tuesday, with the only exception being a
few wrap around showers across the far north as the upper low
departs the region. As we get towards the middle of next week,
warmer air will return, bringing highs back into the 80s for much
of the area. A few showers will also be possible around the
midweek with the next weak cold front.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1100 PM CDT Fri Jul 14 2023
Scattered showers and thunderstorms should taper off in most areas
by issuance time, and skies will clear from west to east. As
skies clear later tonight, patchy fog/low stratus may form in
north central WI, and where more significant rainfall occurred.
Saturday looks to be a bit quieter, with only isolated afternoon
showers and storms, so will not mention any precipitation at this
time.
Both the RAP and HRRR smokie models indicate near surface smoke
will increase on Saturday, reaching the western TAF sites around
midday, and the eastern sites in the late afternoon. Upstream
observations indicate visibilities will deteriorate at times at
least to MVFR as the smoke moves into the area. Kept the
visibility forecast at 6sm with HZ through Saturday morning, with
MVFR/local IFR vsbys arriving in the afternoon. The smoky
conditions should improve from the northwest Saturday evening.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM.....MPC
LONG TERM......Uhlmann
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service Grand Rapids MI
943 PM EDT Fri Jul 14 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 943 PM EDT Fri Jul 14 2023
Line of storms over nrn Il/srn WI continues marching east and
should reach sw Lwr MI shortly after midnight. However the west-
east oriented boundary/convergence zone currently along the MI/IN
border, which has recently set off sct`d strong/svr storms, is
shown to bulge north a bit as the main batch of convection
approaches. Thus we could see some scattered development
occurring ahead of the main line...along the I-94 corridor.
Severe wx risk should wane somewhat by the time the IL convection
arrives here in MI overnight as sfc based instability lowers and
CIN increases. However still can`t rule out strong downburst winds
in environment with deep layer shear > 40 kts penetrating the
shallow sfc inversion and making it to the sfc. Also any deeper
cores will be capable of producing some small hail and locally
heavy rainfall.
Latest RAP shows a level jet of 35-40 kts developing overnight
across srn Lwr MI with PWATs ramping up abv 1.5". It would not be
surprising to see some narrow swaths of 1-2" rainfall amounts set
up and this possibility is reflected in the HREF local
probability match mean product. Fortunately the placement looks to
be south of the heaviest rain that fell Wednesday night, closer
to the I-94 corridor.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 230 PM EDT Fri Jul 14 2023
The biggest forecast question for the short term is convection
this afternoon, overnight and into Saturday morning. Radar as of
18Z has convection firing east of the US 127 corridor with storms
just east of Lansing and north of Jackson. The best area of
convection will be through the eastern half of the state.
A decent LLJ with 35 to 40kts will stream through SW Michigan
this afternoon and evening. The concern will be the coupling of
that jet with the instability due to the short wave trough
swinging through Lower Michigan.
SB CAPE will be upwards of 2000 J/KG so there is plenty of energy
available. Along with this is DCAPE`s of 900 to 1100 J/KG. Given
the DCAPE and the individual cellular convection the main threat
from this storms would be damaging winds.
While PWATS are only slightly anomalously high, there is a a
marginal risk for the excessive rainfall outlook south of I 96.
So water on roadways from locally heavy rainfall will be
possible, especially overnight into Saturday.
All of this potential ultimately stems from a large upper level
low located over central Canada. That low will slowly meander
eastward over the next few days. As that low treks eastward it
will bring chances for showers and storms the weekend and will be
discussed further in the long term.
.LONG TERM...(Sunday through Friday)
Issued at 332 PM EDT Fri Jul 14 2023
- Showers and thunderstorms into Monday, maybe Monday night too -
The aforementioned upper low will be a compact circulation centered
somewhere just north of Minnesota. Lower Michigan, being located
southeast of the upper low, will experience cyclonic and possibly
difluent flow aloft. There are some indications an upper PV maximum
in this flow will translate northeast across the area during this
time; hence, the inclusion of showers and thunderstorms in the
forecast. Precipitation chances look greatest Sunday night as a
significant vort lobe/PV extension with the approaching upper low
pivots across the forecast area.
For Monday, our forecast advertises precipitation chances to wane
during the day in the wake of the exiting vort lobe. However, for
several model cycles now, a substantial proportion of the ECMWF
ensemble members continues precipitation chances even into early
Monday night. This is probably related to trailing upper PV
filaments that may drop into the trough axis, which is nearly
centered over Lower MI Monday night.
- Looking dry Tuesday and wet Wednesday -
Tuesday stands the best chance of being dry next week as things
stand now. After this, there is surprisingly good model consensus
about another PV maximum approaching and bringing showers and
thunderstorms back to the forecast Wednesday.
- Forecast less certain from Thursday on -
After Wednesday, predictability takes a dive. Appropriately,
precipitation chances strongly resemble climatology with perhaps a
slight drying trend in the Friday timeframe. I will hasten to add
that any day 6-7 forecast that`s preceded by multiple convective
episodes should be regarded with a healthy dose of skepticism.
Hence, I wouldn`t read too much into the slightly drier Friday
forecast yet.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 807 PM EDT Fri Jul 14 2023
Convection currently in srn WI and nrn IL will move into srn Lwr
MI after 03-04Z. Will carry a period of showers and tstms in the
TAFs overnight as this passes through, which could produce
occasional IFR conditions in heavy rain along with briefly gusty
winds.
Additional showers and isolated tstms are expected Saturday
morning in the wake of the overnight convection, especially south
and east of GRR. Predominately MVFR conditions Saturday morning
(with some IFR still possible in heavier showers), improving to
mostly VFR in the afternoon as rain ends or becomes more
scattered and cigs lift. Can`t rule out some additional, widely
scattered diurnal tstms developing Saturday afternoon, mainly
east of GRR and AZO.
&&
.MARINE...
Issued at 1151 AM EDT Fri Jul 14 2023
Winds and waves will approach Small Craft Advisory levels today
but should not exceed them long enough to warrant issuing an
advisory. Thunderstorms moving across the waters today could bring
hail and strong gusty winds.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...Meade
SHORT TERM...Ceru
LONG TERM...TJT
AVIATION...Meade
MARINE...Ceru
Area Forecast Discussion
National Weather Service Louisville KY
707 PM EDT Fri Jul 14 2023
...Updated Aviation Discussion...
.Short Term...(This evening through Saturday)
Issued at 320 PM EDT Fri Jul 14 2023
Afternoon satellite imagery shows mostly sunny skies across
southern Indiana and central Kentucky. Afternoon temperatures were
generally in the upper 80s to around 90 with the heat island areas
in the lower 90s. Dewpoints have mixed out a little bit and were in
the lower 70s. Combining the low 70s dewpoints with current
temperatures results in heat indices up in the upper 90s over much
of our forecast area. Some low 100 heat indices were noted out
across far NW KY. A decent Cu field has developed across the region
this afternoon. Some agitation in the Cu field was noted across SE
IL and far SW KY.
For the remainder of the afternoon and evening, will be watching
areas out to our west for some convective development. HRRR has
been pretty insistent that scattered convection may develop across
SE IL/SW IN and WKY this afternoon. Much of this activity looks to
be focused west of the Natcher Parkway. We plan on keeping a slight
chance PoP along and west of the Natcher Parkway and into the
Bowling Green area. Some strong storms are possible here with heavy
rainfall, gusty winds to 50-55 mph, and frequent lightning. This
activity, if it develops, would likely diminish after sunset.
Temperatures this afternoon will remain in the upper 80s before
cooling into the upper 70s to lower 80s by mid-late evening.
For the overnight period, partly to mostly cloudy skies are
expected. An upper level trough axis and surface frontal boundary
will push toward the region from the northwest late tonight. We
expect scattered showers and thunderstorms to develop in advance of
these features. However, there remains some uncertainty on the
overall coverage here with the HRRR runs being more aggressive here
than the 3KNAM solutions. For now, plan on using the blended
guidance here with high chance to low end likely PoPs. Model
soundings do not show all that much instability and shear. So heavy
rainfall, some gusty winds, and lightning look to be main threats
with any of the stronger storms. Lows will remain mild overnight
with readings in the upper 60s to the lower 70s.
For Saturday, scattered convection is expected to be in progress
Saturday morning mainly in the I-65 areas and points west, ahead of
the upper trough axis and cold front. Some diurnal heating is
expected, especially east of the US 27/127 corridor and ongoing
convection across the I-65 corridor may intensify a bit as it heads
into the increasing unstable airmass. Model soundings from
virtually all of the available guidance are pretty meager on MLCAPE
values and bulk shear. However, with bulk shear values near 30kts
in the afternoon, there appears to be a better chance at some
convective organization from the Bluegrass region into eastern KY
Saturday afternoon. Main threats here would be damaging winds and
perhaps some marginally severe hail. Temperatures on Saturday will
likely be strongly influenced by ongoing cloud cover and
precipitation. Highs likely will be in the upper 70s to the lower
80s. There could be some airmass recovery by late afternoon across
southwest IN and possibly into western KY. Should this recovery
take place, another round of storms will be possible, although our
confidence in this remains lower than normal at this time.
.Long Term...(Saturday night through Friday)
Issued at 330 PM EDT Fri Jul 14 2023
Key Messages:
- Dry weather on Sunday.
- Daily shower/storm chances for most of next week.
- Stronger storms probable during the second half of next week.
Synopsis...The medium-range portion of the forecast will be
characterized by a dome of high pressure and positive upper-level
height anomalies stalled over the Southwest US and ridge axis
expanding, at times, through Rockie Mountains all the way up to
southwestern Canada. Meanwhile, a shortwave trough corridor will
remain progressive and extending across the northern half of the
West CONUS with further amplification downstream of the ridge over
the Great Lakes and Ohio Valley. As a result, the weather will
remain somewhat active during the coming week with non-negligible
probabilities of severe weather given the combination of
temperatures, moisture, and background forcing.
Model Evaluation/Confidence...Overall, global dynamical guidance
agrees fairly well on the evolution of the main synoptic pattern;
however, the timing/location/intensity of convection will be driven
by the daily evolution of mesoscale elements that are poorly resolve
at the moment, which also affects the ability to accurately predict
the best window of any MCS-derived severe weather event. That being
said, the CSU ML algorithm and the CFS Severe Weather Guidance are
hinting to a low possibility of strong/severe storms during the 24-h
period starting Thursday 7/20 at 12Z due to the presence of an
unstable airmass focused along a quasi-stationary front and bouts of
shortwave energy aloft.
Saturday Night - Sunday...Depending on the Saturday afternoon
convective coverage and evolution, there could be some lingering
showers and isolated storms lingering over the eastern half of the
forecast area with PoPs eventually diminishing after midnight.
Sunday still looks rain free as a drier airmass and transient
subsidence from regional high pressure dominate the weather
scenario. In addition, there is an Air Quality Alert (AQA) in effect
for Sunday given the advection of smoke from Canadian wildfires over
the Ohio Valley. Aside from health concerns to sensitive groups (see
AQA product), hazy skies and highs in the upper 80s will be common.
Next Week...Increasing temperatures and moisture with increasing
rain/storms chances are expected next week as southerly low-level
flow and convectively-enhanced shortwaves under NW flow aloft become
establish. As previously stated, there is low confidence in any
possibility of strong/severe storms amid this wet pattern, but
consulted guidance indicates slightly better chances during
Wednesday-Friday as MCS-type systems ride a front setting across the
Upper Ohio Valley. Last but not least, as stated in the previous
discussion heat indices across south-central Kentucky might be
reaching the three-digits given highs in the low 90s and high
moisture content.
&&
.Aviation...(00Z TAF Issuance)
Issued at 707 PM EDT Fri Jul 14 2023
Scattered showers and storms continue to persist this evening along
a boundary that stretches from SW IN into southern Kentucky. This
activity is expected to dwindle in coverage with the setting sun,
but additional shower and storm activity may pick up overnight as
the boundary shifts northward. More widespread shower and potential
storm coverage is expected tomorrow morning into the early
afternoon. TAF sites that experience heavier showers/storms could
see brief reductions in visibility and erratic wind gusts.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Short Term...MJ
Long Term....ALL
Aviation...DM
Otherwise, the rest of the previous extended forecast discussion
remains valid:
Key Forecast Message:
* A lull in the active convective stretch appearing probable
Monday-Tuesday following a chance of showers and storms later
Sunday afternoon or evening
An initial cold front passage Saturday evening or night should
scour out any lingering isolated showers and storms in the evening
for a quiet remainder of the night. Sunday has the potential to be
quiet for a decent chunk of the day with breezy westerly winds,
seasonable warmth in low-mid 80s, and dew points lower than what
we`ll observe Friday- Saturday. Recent GFS guidance is much more
aggressive with a short-wave inducing rapid return moisture Sunday
afternoon. Meanwhile, the other guidance favors the main threat
for showers and some storms being primarily in the evening and
overnight with a stronger secondary cold front. This front will be
steered in by a stronger short-wave trough pinwheeling around an
upper low centered over northern Ontario. While confidence is on
the lower side, leaning toward the non-GFS scenario, with the
higher PoPs indicated in the grids late day Sunday into Sunday
evening/night.
Monday-Tuesday look to have an increasing chance to be dry for
much of the area with drier northwest flow, lower dew points
(quite possibly lower than current NBM Td fcst), and comfortable
temps in the upper 70s to lower 80s away from the lake. Only minor
fly in the ointment would be if the lingering moist axis south of
I-80 takes a bit longer to be scoured out, then Monday PM could
have a couple showers and maybe a thunderstorm far south. The
potent heat dome over the southern tier of the CONUS may then
"flex its muscles" mid next week and bring us back into the
convectively active northern/northeastern periphery of the 500 mb
ridging during the Wednesday-Thursday timeframe.
Petr/Castro
&&
.AVIATION...
For the 00Z TAFs...
645 PM...Forecast concerns include...
Scattered thunderstorms this evening.
Chance of thunderstorms Saturday afternoon.
Canadian wildfire smoke Saturday afternoon/evening.
A broken line of thunderstorms crossing into northwest and west
central IL currently is expected to continue moving east across
the terminals through mid/late evening. Some weakening is
possible, but gusty westerly winds will be possible with these
storms. There may be some lingering showers into the early
overnight hours, but the focus for additional showers and
scattered thunderstorms appears to be south of the terminals
overnight into early Saturday morning.
A cool front boundary will move across the area Saturday afternoon
which may also be accompanied by a weak lake breeze near Lake
Michigan. Isolated to possible scattered thunderstorms will be
possible along this front and possible the lake breeze but
confidence is low. Current prob mention has this potential handled
well for now.
Canadian wildfire smoke is spreading south across much of the
upper midwest this evening and the limited guidance that forecasts
smoke shows this spreading across northern IL Saturday afternoon
into Saturday night. Low confidence on visibilities with this
smoke, but mvfr vis is possible. cms
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Memphis TN
1035 PM CDT Fri Jul 14 2023
...New UPDATE...
.UPDATE...
Issued at 1003 PM CDT Fri Jul 14 2023
Showers and thunderstorms continue to impact portions of the Mid-
South this evening. This pattern will persist overnight as a
bowing segment of storms situated over northern Arkansas dives
southeast, impacting portions of the Mid-South within the next
hour or two. Areas at the greatest risk for additional severe
weather are along and west of the Mississippi River, where 2000
J/kg of MUCAPE and 35-40 kts of bulk shear exist. Storms may lose
strength in this area due to a weak capping inversion. Regardless,
gusty winds will remain a threat over the next few hours.
East of the Mississippi River, storms will quickly dissipate.
However, additional redevelopment is possible by 12Z as the
nighttime inversion wanes. Some storms may become strong at this
time with gusty winds possible, but overall the severe threat
remains low.
The larger threat for tonight into Saturday morning is heavy
rainfall as PWAT values approach 2.2 inches. Approaching storms
have a history of producing rainfall rates around 2 inches per
hour, leading to flooding concerns across the northern portions of
Arkansas. As these storms enter the Mid-South, expect efficient
rainfall with flooding possible.
ANS
&&
.SYNOPSIS...
Issued at 251 PM CDT Fri Jul 14 2023
Another round of strong to severe storms should move in overnight
from about 2AM to 10AM tomorrow. Damaging winds and heavy
rainfall will be the primary threats. There is a marginal risk
(level 1 out of 5) of severe weather area-wide overnight; these
storms should be limited in duration, intensity, and/or coverage.
After the early morning convection tomorrow, expect the pattern to
return to normal with hot and humid temperatures and afternoon
showers/thunderstorms for the next few days. Oppressive heat and
humidity return by the middle of next week and heat headlines will
likely be needed.
&&
.DISCUSSION...
(This evening through next Thursday)
Issued at 251 PM CDT Fri Jul 14 2023
Remnants from an MCS are currently making their way across the
Tennessee River into Middle Tennessee and northern Alabama.
Lingering showers and perhaps a few thunderstorms behind this system
will likely continue trickling in through the evening, but the first
of multiple rounds of convection this weekend is more or less
finished as of 3PM Friday. 12Z CAMs depict another MCS ejecting from
eastern Kansas late this evening, marking the next round of
potential severe weather for the Mid-South overnight. This next wave
of storms looks to arrive in eastern Arkansas around 2AM tomorrow
morning, propagating eastward throughout the day. For what it`s
worth, the 18Z HRRR has backed off on the intensity of convection
tomorrow morning, but other CAMs still place a robust MCS at our
doorstep by 2AM.
Storm mode looks to transition from linear and/or bowing segments in
the overnight hours to more discrete and disorganized clusters by
sunrise. Forecast soundings depict extremely high PWATs greater than
2 inches, which is in the 99th percentile of NAEFS climatology for
this time of year. This extremely high moisture content in
conjunction with long, skinny CAPE profiles signifies the potential
for sustained updrafts capable of producing tremendous amounts of
rainfall for a long period of time tomorrow. In other words, the
flooding potential should not be overlooked tomorrow. Any training
storms and/or slow moving discrete cells will quickly pose a
flooding threat. Estimated QPF values across the area for just
tomorrow are between 1 and 2 inches with locally higher amounts,
which may not seem like a lot, but antecedent conditions have
already primed soils to turn any excess water into runoff fairly
quickly.
With regards to the severe potential tomorrow, the general consensus
for the overnight period tonight is about 1500 J/kg MLCAPE and 30
kts of bulk shear. This could definitely support a marginally
organized QLCS early in the morning capable of producing some
damaging winds. Timing of the first wave looks to be about 2AM to
10AM. After noon tomorrow, CAMs paint broad a swath of isolated
showers and thunderstorms more aligned with diurnally driven
convection. However, depending on the coverage and intensity of the
early morning storms, the atmosphere may work itself over and
prevent any secondary convection from developing tomorrow afternoon;
confidence becomes much lower later in the day.
Sunday and Monday will likely be more typical summertime hot and
humid days with isolated showers and thunderstorms along a stalled
frontal boundary draped horizontally across the CWA. The highest
rain chances (30-40%) both days are on the warm, moist south side of
this boundary in north Mississippi. These will most likely be
general sub-severe thunderstorms; guidance is not hinting at much of
any lifting mechanism beyond diurnal heating nor much of any shear
to keep storms organized. Heat indices will start to climb early
next week, foreshadowing the return of excessive heat by midweek.
An upper level ridge over the southern Plains is expected to begin
amplifying on Wednesday, increasing thicknesses and thus
temperatures especially in the Mississippi Delta by midweek. The
aforementioned stationary front looks like it will struggle to clear
the area at all next week, leading to a scenario where high
dewpoints will pool on the south side of the front, creating
oppressively hot and humid conditions for much of the area. Forecast
heat indices by next Wednesday look to exceed 110 degrees in the
Mississippi Delta for the next several days, exceeding 105 degrees
elsewhere. We`ll likely need heat headlines for much of the later
part of the week into next weekend.
CAD
&&
.AVIATION...
(00Z TAFS)
Issued at 634 PM CDT Fri Jul 14 2023
Prevailing VFR conds are expected throughout the TAF period
outside of SHRAs and TSRAs. Short term models continue to
advertise isolated to scattered activity around MEM for the first
3 hours of the TAF. A well organized convective system, currently
over southeast Kansas and northern Oklahoma, will translate SE
overnight and most likely weaken. Timing has not changed too much
from last TAF set, however, tempo groups have been added for best
timing on station as well as the wind shift. Behind the exiting
system, scattered TSRAs and SHRAs may occur through late morning.
Scattered diurnal activity will result in VCTS at all sites
by late tomorrow afternoon. Winds will generally be from the
southwest, but will temporarily shift to the northwest behind the
convective system overnight.
AC3
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...JDS
AVIATION...AC3
Area Forecast Discussion
National Weather Service Nashville TN
915 PM CDT Fri Jul 14 2023
...New UPDATE...
.UPDATE...
Issued at 900 PM CDT Fri Jul 14 2023
It`s still uncomfortably humid outside at this hour with
dewpoints well into the 70s and temperatures still in the 80s.
Overnight is looking mostly cloudy and dry for the most part. An
MCS currently over Arkansas will eventually make its way here by
Saturday morning. CAMs suggest convection filling in from Kentucky
down through Alabama and entering Middle Tennessee after 8 AM.
With all of the moisture, PW values are around 2" so heavy
rainfall is likely, but storm motion is still fast enough that
widespread flooding does not look likely. There is some
instability tomorrow, so a few rumbles of thunder are possible,
but widespread severe does not look to be the case. The only real
changes made to the forecast tonight were some PoP adjustments to
better reflect the Saturday morning convection. Everything else is
on track.
&&
.SHORT TERM...
(This afternoon through Saturday Night)
Issued at 240 PM CDT Fri Jul 14 2023
After a long wait, storms have finally reached Middle TN at
forecast time. Instability numbers from the RAP analysis, if you
take them at face value, are pretty decent ahead of this batch of
storms. Numbers are running around 3500 J/Kg. However, with only
25-30 kts of shear and no real synoptic forcing to keep this
activity going, we`re seeing the results: showers with scattered
thunder. There could be a little wind gust mixed in here and
there, but these should remain below severe criteria. This batch
of precip will push eastward through the remainder of the
afternoon, likely losing more and more of its punch as it does so.
As we move into the overnight hours, I can`t rule out some
additional development, but without any organization, these should
relatively tame.
Additional convective activity is expected to develop on Saturday
morning. Forecast soundings are still very unimpressive, and with
overnight cloud cover and storms expected to spark before we can
get good instability going, I`m not overly concerned about a wind
threat. PWs are up there, though. Rainfall could be heavy at
times, but with storm motions on the order of 15 kts, flooding
issues should be limited. Most, if not all, guidance shows the
bulk of Saturday`s activity clearing the Cumberland Plateau by the
early evening hours.
&&
.LONG TERM...
(Sunday through next Friday)
Issued at 240 PM CDT Fri Jul 14 2023
Get ready for these rain chances to drop it like it`s hot and
temperatures to go up up! Starting of Sunday, all models seem to
agree on the placement of an upper-level low above Minnesota that
will put us in the axis of a synoptic trough. What this means is
that next week weather will be dominated by omega blocking pattern
and us entering a synoptic ridge from Monday night into Tuesday.
This will bring drier conditions, sinking air motions, and high
temperatures. The GFS does show a subtle short-wave ridge around
monday afternoon, so if it does develop, it can enhance heating a
bit. It should be noted that models are trending towards MCS
development to our northwest early Monday. There is model
disagreement however, on the whether or not the MCS can reach the
middle Tennessee area and its precise timing. The GFS and Canadian
show subtle short-wave troughing on Wednesday morning, but again we
will continue to be in an upper-level ridge pattern and that will
limit any lifting. Some models show small rain chances for
Wednesday, but if they do occur it would like be isolated showers.
The most important message of this forecast, though will be the
rising heat next week. An upper-high pressure system will move
through southwest CONUS and start extending into our area on
Wednesday. This will keep us effectively out of the trough up to our
north and in a synoptic pattern that will only enhance heating. As a
result we can see the possibility of a heat advisory being issued
due to high heat indices for Wednesday, Thursday, and possibly
Friday. The ECMWF shows the high pressure directly over Western TN
bringing with it significant negative vorticity advection, which
means sinking air and clearer skies. Without clouds to keep
temperatures lower, if trends continue we might see max temps at
100. Overall ensembles are showing confidence it upper 90s for max
temps and upper 70s for the low at the end of the week. Friday
another synoptic low will begin digging into the Great Lakes region
with models pointing to a return to northwesterly flow by late
Friday.
&&
.AVIATION...
(00Z TAFS)
Issued at 640 PM CDT Fri Jul 14 2023
Conditions are currently VFR for middle Tennessee. CAMS show some
development of showers and thunderstorms in the morning and
afternoon. CAMS show some disagreement on timing of storms, but
confidence is greater for the northern part of Mid TN. There is
low confidence in fog for SRB and CSV, since we do have overcast
skies and that should inhibit the development of fog, but some
models do indicate MVFR conditions possible for SRB overnight.
Winds will be variable and below 5 kts overnight until the morning
when they will increase to 5-10kts and become
southwesterly/westerly.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 74 88 72 92 / 40 90 50 10
Clarksville 74 87 71 93 / 60 90 30 0
Crossville 68 80 65 82 / 30 90 60 20
Columbia 72 88 70 91 / 50 90 60 10
Cookeville 70 83 68 85 / 40 90 80 10
Jamestown 69 81 67 83 / 30 90 80 20
Lawrenceburg 72 88 69 90 / 40 90 70 10
Murfreesboro 72 88 70 91 / 40 80 70 10
Waverly 72 87 68 91 / 70 90 30 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Baggett
SHORT TERM...Unger
LONG TERM....Mancilla
AVIATION.....Mancilla
Area Forecast Discussion
National Weather Service Norman OK
1054 PM CDT Fri Jul 14 2023
...New AVIATION...
.SHORT TERM...
(This evening through Saturday)
Issued at 333 PM CDT Fri Jul 14 2023
This morning, a mid-level shortwave was centered in the vicinity
of the WY/NE/CO/KS junction, per observed height falls on the 12Z
500mb RAOB chart. This feature is tracking slowly southeastward
into the central plains as a cold front pushes southward across
central Kansas. A line of strong to severe thunderstorms have
already developed along the front - extending just northeast of
Dodge City to near Salina to Lawrence. The outflow boundary, seen
on satellite/radar imagery over southwest Kansas, is estimated to
move into far northwest Oklahoma within the next few hours, would
expect thunderstorms to gradually develop westward along the front
as it propagates towards Oklahoma.
The cold front is expected to reach northern Oklahoma between
7-9PM and slowly move southward overnight with storms possibly
moving through the metro between 11PM - 1AM. The RAP and HRRR have
prog`d MLCAPE values over northern Oklahoma near 2000 to 4000
J/kg with 0-6 km shear near 25 knots currently, and shear is
forecast to increase to 40-50 knots by late evening. With
profiles showing substantial CAPE within the HGZ, large hail along
with damaging wind gusts are possible. There remains uncertainty
as to the strength of storms as they move into central Oklahoma.
We issued a Flood Watch for parts of central Oklahoma tonight as
morning models suggested 1 to 3 inches of localized rainfall in
areas that have already received 4 to 7 inches of rain within the
past 7 days.
Tomorrow is forecast to be much cooler and below-average, in fact.
Rain chances diminish by mid-morning.
Thompson
&&
.LONG TERM...
(Saturday night through next Thursday)
Issued at 333 PM CDT Fri Jul 14 2023
A shortwave brings a chance of showers/storms to parts of the area
Saturday night, with below-average temperatures continuing on
Sunday. The heat returns Monday through mid-week as a strong upper
ridge advances towards the south-central plains. Although heat
index values are forecast to rise into the triple-digits
(beginning Monday), the good news is that dewpoints are forecast
to be lower than recent days (think 60`s). Another front then
enters our area end of the week. This upcoming week looks dry. The
next best chance of rain/storms is Thursday night.
Thompson
&&
.AVIATION...
(06Z TAFS)
Issued at 1052 PM CDT Fri Jul 14 2023
Showers and thunderstorms will continue through the late night
hours, with another round possibly entering western OK late
Saturday morning. At least some MVFR cigs and visbys will be
possible behind the precipitation early tomorrow morning, but it`s
currently unclear how low they will drop. The most likely
terminals to be impacted by the aforementioned will be from I-40
northward. Winds will generally become northerly tomorrow.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 93 71 86 69 / 20 70 20 30
Hobart OK 98 69 87 67 / 30 20 20 30
Wichita Falls TX 103 75 93 72 / 40 10 10 30
Gage OK 94 66 87 65 / 30 60 10 30
Ponca City OK 90 68 89 68 / 30 70 10 10
Durant OK 96 76 92 73 / 30 20 20 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch until 4 AM CDT Saturday for OKZ017>020-024>026-
028>032.
TX...None.
&&
$$
SHORT TERM...01
LONG TERM....01
AVIATION...03
Area Forecast Discussion...UPDATED
National Weather Service Paducah KY
838 PM CDT Fri Jul 14 2023
.UPDATE...
Issued at 838 PM CDT Fri Jul 14 2023
A few stubborn and particularly slow moving cells continue over
SRN IL. Also watching convection near St. Louis metro. This
appears to be associated with a general increase in large scale
ascent as a weak shortwave trough moves in from the west.
Convection over southwest Missouri is steadily propagating
southeastward, but numerous outflow boundaries in the area will
need to be watched as they move into more unstable air over
southeast Missouri in the late evening. Severe risk will likely be
mitigated by decreasing sfc temps and marginal shear but a severe
storm or two will remain possible given the rich low level
moisture and 2000-2500 J/kg of remaining MLCAPE. Very heavy
rainfall will also be a concern with any cores that go up until
storm motion increases as the trough gets closer by 11p-12a.
UPDATE Issued at 624 PM CDT Fri Jul 14 2023
Local thunderstorms will probably decrease in coverage/intensity
through early evening. Watching a complex over KS/MO. It has a lot
of rain-cooled air to work through but could maintain some
intensity as it moves into SEMO in the 10p-12a range tonight.
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 305 PM CDT Fri Jul 14 2023
The main concerns in the short-term portion of the forecast will be
the potential for showers and thunderstorms through Saturday evening
with continued hot and humid conditions. Overall confidence in
convective timing and placement
Tonight through Saturday: A strong shortwave associated with ongoing
convection over central into eastern Kansas this afternoon, is
progged to shift east and southeastward overnight. This would bring
the decaying remnants to the Quad State very late tonight into early
Saturday morning. Most of the hi-res guidance diminishes the storms
as they progress eastward, so confidence in the overall coverage and
intensity is low. If it does hold together, a few stronger storms
could work into western portions of the area later tonight,
especially after midnight. Any showers/storms associated with this
feature should push east of the area by mid morning. A weak frontal
boundary will also pass through the area through early afternoon,
which may help to focus additional showers or storms. Shear and
instability look to be fairly weak, so not expecting much storm
organization for Saturday. Highs will be in the 80s for most
locations with overnight lows in the 70s.
After the frontal boundary passes through the area expect slightly
less humid air to arrive Saturday night into Sunday (it will still
be hot) while northwest flow lingers aloft. HRRR smoke products also
bring smoke from Canadian wildfires south through a good portion of
the area late Saturday night through Sunday; therefore, have added
haze to the forecast and issued an Air Quality Alert for southwest
Indiana. Again, that alert is for Sunday. Highs are expected to be
in the low to mid 90s. Overnight lows will be in the upper 60s to
around 70.
.LONG TERM...(Monday through Friday)
Issued at 305 PM CDT Fri Jul 14 2023
Northwest flow will linger through the first part of the work week;
however, brief ridging is expected to arrive for Wednesday into
Thursday. A couple shortwaves are expected to brush through the
northern portions of the Quad State area, which will give additional
chances of scattered showers and thunderstorms. Again, timing and
placement of these waves are difficult at best to pin down this
early. At this point have kept mainly an afternoon/evening mention
in the forecast during peak heating. Heavy rain and a few strong to
severe thunderstorms will be possible with increased shear and
instability with each wave that passes through the area. The
increased ridging across the area Wednesday into Thursday will allow
temperatures to soar! Highs are expected to be in the upper 80s and
low 90s for Monday and Tuesday before warming into the upper 90s to
around 100 degrees for WednIn general the exact
evolution is still fairly uncertain but a general increase in
convection is expected over the area by around midnight, with some
of the locesday into Thursday. Heat Index values
will likely warm to near 110 degrees or so for Wednesday into
Thursday and much of the area will likely need a Heat Advisory at a
minimum. A few thunderstorms will be possible across the north,
but overall coverage may be limited due to the warmer air aloft.
&&
.AVIATION...
Issued at 624 PM CDT Fri Jul 14 2023
Thunderstorms should gradually diminish in intensity in the
EVV/OWB/MVN area through the next hour, persisting slightly longer
north of CGI. Another complex of storms may arrive in the 03-06z
timeframe across SEMO possibly moving into the rest of the area
later in the overnight. A westerly wind shift is expected early
Saturday morning. Some patchy fog or low cigs are possible around
daybreak but a prevailing VFR sky appears likely through much of
the rest of the day.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...JGG
SHORT TERM...KC
LONG TERM...KC
AVIATION...JGG