Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/29/23
Area Forecast Discussion
National Weather Service Gaylord MI
1157 PM EDT Wed Jun 28 2023
.UPDATE...
Issued at 938 PM EDT Wed Jun 28 2023
Significant return flow is underway in WI and western upper MI,
behind surface high pressure over Lakes Huron/Erie. That return
flow is much weaker here, and incoming showers are decreasing
greatly as they move into western and northern sections. (00Z
observed PWAT values were 1.14" at GRB vs 1.01" at APX.) A light
sprinkle or two has been reported out of E Jordan.
Hard to see more than a sprinkle or two thru most of night, given
that forcing remains weak and unfocused. Perhaps actual showers
can sneak into western sections (especially western Chip/Mack Cos)
toward first light (which is of course quite early). Just of hint
of MuCape (less than 200 j/kg) is progged overhead overnight. The
main plume of elevated instability will work from southern MN to
southern WI tonight, and any potential for stronger convection
thru 12Z will stay w of Lake MI.
Though most of northern MI has escaped the worst of the smoke
(for a little bit), denser smoke/haze remains trapped in parts of
the marine layer over the Great Lakes. Vsby restrictions are seen
at Rogers/FKS/Ludington, and especially MBL (which is IFR). As
temp/dew point spreads close, this will transition to some coastal
fog/smog. Patchy fog is possible elsewhere, though increasing
cloud cover should keep this limited.
&&
.NEAR TERM...(Through Tonight)
Issued at 214 PM EDT Wed Jun 28 2023
High Impact Weather Potential: An isolated thunderstorm possible
late tonight over northwest lower Michigan.
Upper level wave near the Arrowhead of Minnesota with a poorly
defined warm front extending eastward toward Lake Michigan and an
associated cold front stretching southward through Wisconsin. Ridge
axis currently across Michigan will slide east tonight with low
level moisture advection pushing PWAT`s toward 1.50" over far
western parts of the area by Thursday morning. Embedded shortwave
trough rotating around the parent upper feature will push into
northern Michigan later tonight with surface warm frontal boundary.
Limited forcing/moisture through much of tonight, with better rain
chances arriving on Thursday as mid level dry air wedge gradually
erodes and convection fires on the leading edge of a developing
500mb jet. Will confine the highest pops tonight west of US-131 in
northwest lower and M-123 in eastern upper. Mid level lapse rates
steepen late tonight with the arrival of more favorable kinematics
and an isolated thunderstorm is possible over far western parts of
the area.
Combination of more clouds and increasing low level moisture will
keep temperatures mild tonight with lows ranging from the 50s
inland to the lower 60s along the Lake Michigan coast.
RAP vertically integrated smoke forecast shows increasing amounts of
smoke/haze pushing back into northern Michigan late tonight in
advance of the upper wave. An Air Quality Advisory remains in
effect through Thursday.
&&
.SHORT TERM...(Thursday through Saturday)
Issued at 214 PM EDT Wed Jun 28 2023
HIGH IMPACT WEATHER POTENTIAL: Moderate...watching potential for
strong to severe(?) storms Thursday afternoon...
PATTERN SYNOPSIS/FORECAST:
Subtropical ridging remains steadfast over the southern US...with
split flow over the western continent, as troughing holds on over
the SW US...and broad troughing over the E US beginning to lift out.
Flow a little more zonal across the northern tier of the country as
energy slips into the Upper Midwest...and additional troughing
pinwheels down through Manitoba. Some cloud cover and attendant
surface precip out ahead of this Upper Midwest feature...along the
perimeter of steeper mid-level lapse rates... and amid some theta-e
advection on strong southwesterly low-level return flow...and deeper
moisture (pwats approaching or in excess of 1.5 inches). Smoky skies
diminishing (at least for a time) over northern Lower MI...as 1016mb
surface high pressure settles into the region between the departing
surface system, now out off the East Coast...and the incoming
disturbances from the west/northwest. Do see some indications that
the surface system over the Canadian Prairies may be deepening a bit
attm. Further upstream...broad and slightly anomalous troughing
maintains a hold on the north central Pacific for the time being.
Energy to our west this afternoon expected to slip eastward
tonight...as the niblet over the Canadian Prairies continues to
march southeastward. For now...it appears the main shortwave will
scrape us to the north Thursday into Thursday night...as energy over
the SW US slips eastward...and briefly tries to build the ridge over
the Mid MS Valley. Anticipate strengthening thermal gradient between
these features...and also development of a N-S surface front that
should swing through later Thursday into Thursday night and fire off
some convection.
Aforementioned upstream feature looks to slowly meander through the
flow this weekend...with the shortwave to our northwest hanging out
nearby...such that we`ll be looking at general troughiness again,
with potential for things to remain slightly unsettled...though
nothing overwhelmingly screams "washout" attm.
PRIMARY FORECAST CONCERNS: Rain/storm chances through the period...
Appears that we will be in the warm sector of the system to our west
Thursday...with abundant low-level warm advection into the region,
as well as some potential for a weak zonal boundary to linger
potentially in the Straits region. This should favor increasing
moisture as well...with signals for pwats to increase above 1.5
inches. While we should have a capping inversion for a while...there
are signals that diurnal heating may be enough to almost break the
cap during the afternoon...or at least, weaken it to the point where
it can be easily overcome. Above this...with steeper lapse rates
just downstream to our southwest (near enough to be of
concern)...suspect we will develop some pretty good instability
aloft (potential for 1000-2000 J/kg MUCAPE) as we warm during the
afternoon. Signals point toward potential for convection,
potentially severe, with hail as a threat, given the potential for
beefier CAPE (per soundings), though wind can`t be entirely ruled
out either. Assuming this idea verifies...there are signals for some
ongoing convection along the Lake Michigan coast early in the
day...and up into the EUP where there could be some activity most of
the day (perhaps a bit of warm advection training?...though they may
be far enough north of the warm front to remain capped for most of
the day, too)...which should spread eastward with time during the
afternoon as we get into diurnal heating, as well as the approach of
the shortwave.
This being said...the tiny details will, of course, play a large
role...and there is still a lot of variability in guidance as to how
exactly this will evolve. If we are unable to get as much diurnal
heating (such as, if the smoke/haze ends up limiting max temps...or
cloud cover puts a damper on things), we may limit convection to
some degree, depending on the amount of forcing we end up with. We
may be somewhat favorably positioned for better synoptic support, if
we are able to get the aid of some shortwave niblets aloft...though
these may be at least in part driven by upstream convection tonight.
Either way...will be keeping a close eye on this, as it does carry
potential for severe weather, especially the further south you
go...and the higher pwat values associated with this system could
indicate potential for flash flooding, especially where it just
rained 1-3 inches over the weekend.
Looks as if the boundary will be slow to depart...and potentially
become a little more zonal in nature going into Friday as it slowly
sinks south through the region...potentially stalling off to our
south. Not out of the question some synoptic forcing could linger in
the area...with the left exit region of the jet slipping in...which
suggests we could see a little bit of activity hang around into the
morning. Looks as though the dry slot slips in during the
day...which may focus itself over northern Lower, and leave eastern
Upper under some lingering moisture. Won`t be impossible to see a
bit of lake breeze activity Friday afternoon, which could lead to
some meager activity, particularly along the Lake Huron side of
things and where the better moisture should linger, and where there
could be better diurnal heating. Additionally, will look for some
activity across the EUP where low-level moisture is more likely to
hang on.
Saturday...another niblet swings by from the north...though for now
it appears this will not have as much of an impact as Thursday`s
niblet...with the bulk of the deeper moisture and instability locked
up to our south behind the boundary (assuming it gets out of our
CWA). Even so...not impossible there could be some afternoon lake
breeze pop-up showers/storms near Lake Huron, where the better
convergence is likely to be (with prevailing northwesterly flow),
and also across the EUP where there is more likely to be assistance
from the niblet.
.LONG TERM...(Saturday night through Wednesday)
Issued at 214 PM EDT Wed Jun 28 2023
HIGH IMPACT WEATHER POTENTIAL: Minimal for now...though watching for
scattered showers/storms at times through the holiday weekend...
PATTERN SYNOPSIS/FORECAST:
Appears that the trough to our north...and the shortwave to our
southwest...will try to connect with one another for the latter half
of the weekend....as the subtropical ridge builds over the SW
US...and another broad trough begins to trek into western Canada.
Attm...flow looks as though it could be a bit split over the region,
or at least, attempt to become so, through the remainder of the
holiday weekend...as that energy over western Canada slowly makes
its way eastward. For now...this suggests we may see a northward
shift in the stalled boundary, which could bring more precipitation
into the area going into early next week...as well as increasingly
warm temps on southwesterly flow going into the fourth and midweek
ahead of the upper trough. Not out of the question we get more
active as the upper trough itself approaches toward midweek. This
idea seems valid, though run-to-run inconsistencies in solutions
suggests there may yet be some uncertainty in the forecast for the
Fourth and beyond.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1155 PM EDT Wed Jun 28 2023
IFR vsbys at MBL tonight.
High pressure is over Lk Huron and wrn Lk Erie. Increasing
warm/moist southerly flow is increasing mid/high clouds and spotty
precip in the western Great Lakes. Those clouds will increase
here, especially on Thursday, along with increasing chances for
SHRA. Would not preclude a TSRA, especially in the afternoon/
evening. Have added VCTS for now to PLN/TVC/MBL.
MBL is dealing with IFR conditions in HZ/FU, as smoke trapped in
the marine layer over Lake MI has drifted onshore. This may morph
into IFR fog (smog) tonight as temps cool.
Se winds, will become somewhat gusty on Thursday.
&&
.MARINE...
Issued at 214 PM EDT Wed Jun 28 2023
Winds and wave will remain below SCA criteria thru Friday.
Chances of showers and thunderstorms will increase late
tonight...with unsettled wx expected for the rest of the week and
into the weekend.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JZ
NEAR TERM...JK
SHORT TERM...FEF
LONG TERM...FEF
AVIATION...JZ
MARINE...JK
Area Forecast Discussion
National Weather Service La Crosse WI
1037 PM CDT Wed Jun 28 2023
.UPDATE...
Issued at 1005 PM CDT Wed Jun 28 2023
Quite a few storms are currently located across west-central and
northwest Wisconsin. There are even a few supercells. These
storms are located in the left exit region of a 500 mb speed max
moving east across southern Minnesota. SPC Mesoanalysis continues
to show that Clark and Taylor will be in this favorable left exit
region from 28.05z through 25.07z. With the effective shear
remaining greater than 40 knots, there will continue to be the
possibility of supercells. Hodographs continue to support
splitting supercells. Main threats are still large hail and
damaging winds. The wind threat is highly dependent upon on how
the storm coalesce their cold pools.
Meanwhile, further south near Interstate 90 and south, this area
will be primarily be in the right exit region of this jet. This
will result in subsidence in this area. In addition, 10 to 12C
700 mb temperatures will provide mid level capping in this area.
As a result, storms look less likely in this area.
UPDATE Issued at 722 PM CDT Wed Jun 28 2023
The best instability and low level convergence remains to
northwest through at least 9 PM. It continues to look like we are
going to have to wait for the cold pool to develop and sag this
boundary southwest into our area. There is plenty of 0-6 km shear
for maybe a few supercells along this boundary. With DCAPES
between 800 and 1000 J/kg and dry mid levels, damaging winds will
be a possibility. While there is a skinny CAPE profile, supercell
shear could overcome that and we still could see some large hail.
With 700 mb temperatures between 10 and 12C along and south of
Interstate 90, there is some uncertainty on how far south this
convection will get.
&&
.DISCUSSION...(This evening through Wednesday)
Issued at 250 PM CDT Wed Jun 28 2023
Key Messages:
- Scattered thunderstorms tonight with some strong to severe
especially north of I94
- Moisture lingers into Thursday with possible re-development in
the afternoon for parts of southwest Wisconsin
- Air Quality Alerts Continue
This Afternoon`s Conditions and Subsequent Setup:
This afternoon, cyclonic flow is evident on surface observations
over west-central Minnesota with an upper level perturbation
exhibiting cyclonic rotation quickly advecting through central to
eastern South Dakota on an east-northeast trajectory. Surface low`s
attendant surface warm frontal boundary extending east through
central Minnesota and into north central Wisconsin, grazing our
northern-most county of Taylor. A secondary moisture gradient
bifurcating the forecast area, northwest from the surface low in
central Minnesota to southeast in far southwest Wisconsin,
approximately along the Mississippi River Valley. To the east of
this boundary in the drier, smokier air lies a much more stable air
mass with dewpoint depressions near 20 degrees and low level lapse
rates of 5-7 C/km. Farther west and south, a third surface boundary
evident in slightly veering winds extending to an area of surface
cyclonic flow over eastern Nebraska. Early afternoon (~18Z) radar
imagery shows precipitation and storms to the north, in northern
Wisconsin, and to the south, in central Iowa, tied to both warm
fronts.
Air Quality Alerts Continuing:
Within the aforementioned warm sector, southeasterly surface
winds are advecting higher concentrations of haze and smoke from
northern Illinois into southern Wisconsin this afternoon. The
highest concentrations of PM 2.5 >150 ug/m3 extend from southwest
to northeast, in a line from Oelwein, IA to Green Bay, WI.
Concentrations over La Crosse and Rochester near 100 ug/m3 Edge of
increased near surface smoke evident in visibility observations
from south-central Minnesota into north- central Iowa with a
slight westerly component to the mostly southerly winds. Reprieve
from hazardous conditions not expected until overnight tonight
with southeasterly advecting surface frontal passage from central
Minnesota through west-central Wisconsin into central Wisconsin.
Therefore, Air Quality Advisories for the PM 2.5 set to expire at
midnight for Minnesota, although may be slightly extended, and at
noon Thursday for Wisconsin.
Northerly Extent For Strong To Severe Storms Tonight:
With the aforementioned surface frontal/low passage overnight,
strong to severe storms possible primarily east of the Mississippi
River. Initiation in eastern Minnesota near the 00Z hour tied to low
level lapse rates >8C/km, building diurnal instability (1000-2000
J/kg SBCAPE; HREF 29.12Z), and surface low triple point. The MLCAPE
boundary this afternoon is tied to the aforementioned moisture
boundary bifurcating the forecast area and is expected to shift and
increase slightly to the northeast with mean flow and forcing into
this evening. Will be a very thin axis of instability with the
aforementioned drier, stable air mass to the east from north into
south-central Wisconsin. The limited northerly extent for strong
storms tied to this limited northerly extent of instability.
Southerly Extent Of Strong to Severe Storms:
Locally, from southeast Minnesota to western Wisconsin, limiting
factor will be a quite stable air mass from WAA at 700 mb of 10-
20C/12hr resulting in low lapse rates of 3-4C/km. This stable
airmass expected to direct/force storms along its boundary. In other
words, northerly extent of more stable air mass will depict southern
edge of strong to severe storms and precipitation.
Severity and Shear:
Adequate, increasing with height shear magnitudes (0-3km: 25 kts; 0-
6km: 40-50kts / RAP.28.17Z) suggest initial storm mode of supercells
on the boundary. Boundary motion to the east-southeast expected to
be slightly faster or equal to storm motion initially, limiting
discrete supercell extent. While 0-3 km shear vectors are at a 45
to boundary orientation, 0-6 km slightly more northwesterly,
resulting in more perpendicular orientation, providing more shear
realization.
Potential Impacts and Hazards:
In summary, stronger storms limited to the north from thin, shunted
axis of higher instability and to the south by more stable, capped
air mass. Initial storms around 7-9 pm with a mode of supercells
possible, splitting with quite linear hodographs, with slower storm
motion than the boundary limiting supercell extent. Storm mode then
expected to quickly turn multicellular with congealing cold pools
and sufficient shear into the overnight hours, reaching the
Interstate 94 corridor from 12-2am. While mid level lapse rates are
only 5-7C/km, hazards of hail and damaging winds most likely in a
relatively confined area, affecting locally in central Wisconsin,
decreasing as they continue east-southeast with decreasing
instability. The HREF (28.12Z) 40 dBz paintball and Updraft
Helicity depicts this well with an area from east-central
Minnesota into west- central Wisconsin rapidly decreasing as it
reaches our central Wisconsin counties.
Storm Chances Thursday Afternoon:
The more southerly aforementioned surface boundary lingers across
our southern counties from northeast Iowa into southwest Wisconsin
through Thursday, providing afternoon storm chances. HREF
(28.12Z) depicts increased instability (1000-2000 J/kg SBCAPE)
grazing our southern most counties in far southwest Wisconsin and
northeast Iowa. Diurnal timing with best heating pushes confidence
for greater impacts into Illinois and east-central Iowa but still
will be something to keep an eye on.
Thursday night through the Independence Day holiday:
The latest HRRR for the Thursday night period has some isolated
storm re-development in a west to east line with a skinny area of
moisture and a reinforcing boundary/cool front. Did maintain some
low pops for Thursday evening, however coverage appears low.
Satellite/lightning shows quite a bit of isolated storm activity
with the low that will track into the Great Lakes. This looks to
remain north of the forecast area Thursday night an Friday. We
remain in-between the main storm tracks Friday through Saturday
as the closed low over Ontario rotates through the Great Lakes and
a mid-latitude trough over the Rockies and Central Plains
migrates to the Mid-Mississippi Valley just south of the forecast
area. Saturday night and Sunday this trough tries to phase with
the trough across Canada, but may move east of the forecast area
leaving the region mainly dry. A ripple in the northwest flow
aloft could lead to isolated convection ahead of the developing
into Monday. There continues to be timing differences with the
next cold front to affect the area for Independence Day and we`ll
continue to look at this as we hone in on the holiday forecast.
Temperatures should be in the 80s through the weekend with 80s
and lower 90s early next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1038 PM CDT Wed Jun 28 2023
Thunderstorms chances have decreased for KLSE overnight. This is
due to this area seeing 700 mb temperatures near 10C and also
being in the right exit region of the 500 mb jet. As a result,
the VCTS was removed from this TAF. Also, there continues to be a
very low chance of thunder for KRST, so kept the thunderstorms
out of this TAF site too.
Smoke will likely to produce MVFR visibilities through much of the
night and then continue into Thursday morning. Kept the smoke at
KRST through 29.15z and KLSE through 29.18z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...Boyne
DISCUSSION...JAR/Zapotocny
AVIATION...Boyne
Area Forecast Discussion
National Weather Service Buffalo NY
945 PM EDT Wed Jun 28 2023
.SYNOPSIS...
Smoke will continue to move across the region tonight. A
surface ridge will then cross our region Thursday with fair
weather and comfortable levels of humidity. A trough of low
pressure will approach the region Friday, bringing unsettled
weather which will last through the weekend.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
There are a few lingering showers east of Lake Ontario as a
mid-level trough across northeastern NY gradually exits into
northern New England. Wildfire smoke has diminished some across
the region late this evening, but still remains across much of
the area. An Air Quality Alert is in effect until midnight
Thursday night with unhealthy conditions for western and north
central NY.
A mid-level ridge and surface high pressure will move into the
region tonight through Thursday. Dry conditions will ensue with
calm winds. The flow aloft remains favorable for wildfire smoke
to linger across the region through at least Thursday. The HRRR
and RAP smoke model forecasts show a decrease in concentration
of smoke but weak flow aloft, smoke will likely linger. Lows
tonight will fall to the 50s with highs on Thursday reaching the
upper 70s to low 80s. Patchy fog is possible in the Southern
Tier river valleys.
A shortwave trough will likely ride the mid-level ridge across
the Great Lakes region Thursday night. A southerly flow will
pick up across the region with low chances for showers entering
western NY by late Thursday night. Lows will fall to the upper
50s to low 60s.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A mid level trough over the central Great Lakes Friday will pull
east across the eastern Great Lakes and into the Northeast by Sunday
morning. Meanwhile a few shortwave troughs will pass through the mid-
level longwave. The first of which will enter the lower Great Lakes
Friday afternoon. This will increase moisture, instability and weak
forcing to support a few scattered showers and thunderstorms by
Friday afternoon and through Friday night. The next convectively
driven shortwave trough will then support more weak forcing
Saturday. This combined with the local mesoscale boundaries will
support chance for a few more scattered showers and thunderstorms
Saturday.
With regards to temperatures, Friday will be the warmer of the two
days with highs inland ranging in the mid to upper 80s. Then
Saturday, highs will range in the upper 70s to low 80s.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A mid/upper level trough will generally be in place across the
Northeastern CONUS during the period. This will promote frequent
chances for showers, with afternoon/evening hours generally
favored due to diurnal instability.
On Sunday, model consensus suggests a frontal boundary will be
stalled near the NY/PA state line with a weak shortwave possibly
moving through. This is likely to result in showers and a few
thunderstorms, especially across the Southern Tier. After this,
timing shortwaves will be difficult with diurnal instability trends
and subtle boundaries primarily driving precipitation chances.
High temperatures will mainly in the upper 70s to lower 80s.
On Wednesday, most guidance begins to build an upper/mid level ridge
across the Great Lakes region which will lower the risk of showers
and storms. It will also be a bit warmer with partial sunshine
supporting highs in the lower to mid 80s.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
A combination of lower ceilings from an overcast deck and a plume of
smoke from wildfires has produced a mixture of MVFR and IFR
conditions across the region late this evening. Expect lower
cigs due to clouds to continue to dissipate from west to east
tonight. Ceiling and visibility restrictions due to smoke are
more difficult. In general, model guidance suggests a trend of
improvement tonight with less issues with smoke on Thursday.
Still, confidence is low. Otherwise, high pressure will build in
with mainly clear skies and VFR flight conditions outside of
any smoke through Thursday. Patchy fog possible late tonight in
Southern Tier river valleys which may impact the KJHW terminal.
Outlook...
Thursday night...Mainly VFR.
Friday...VFR. A chance for afternoon showers and isolated
thunder.
Saturday and Sunday...Mainly VFR with a chance of showers and
thunderstorms.
Monday...Mainly VFR with MVFR/IFR in showers and thunderstorms.
&&
.MARINE...
Winds and waves will slacken tonight as surface high pressure
pushes towards our region from the west. Fair weather Thursday
and light winds on the Lakes as this surface high crosses.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...HSK/Thomas/Apffel
NEAR TERM...Apffel/HSK
SHORT TERM...EAJ
LONG TERM...Apffel
AVIATION...Apffel/HSK
MARINE...Apffel/HSK/Thomas
Area Forecast Discussion
National Weather Service Cheyenne WY
609 PM MDT Wed Jun 28 2023
.SHORT TERM...(This evening through Friday night)
Issued at 300 PM MDT Wed Jun 28 2023
Active weather continues through at least Friday across the CWA.
Forecast challenges deal with severe thunderstorms today and
Thursday. Followed by heavy rainfall possibly leading to flash
flooding Thursday and Friday.
Severe Thunderstorm Watch 408 in effect this afternoon already for
much of the CWA excluding Carbon and Albany County. 2 PM RAP from
SPCs mesoanalysis page shows SBCAPE ranges from 2000 to 3000J/KG.
A little capping area over Converse County around Douglas with
around 50/75J/KG CIN. All other areas are uncapped at this time.
0-6km shear 45-50kts with 0-3km helicity right around 100 m2/s2.
Not an ideal environment for tornadoes with this low
helicity...but great for large hail and strong downburst winds.
HRRR/RAP simulated radar suggesting 2 or 3 supercells through the
late afternoon/early evening...mainly across Converse/Niobrara
Counties and northeast Laramie and southern Goshen
Counties...moving east into the Panhandle towards 23Z and 00Z.
Upper shortwave moves into the CWA during the evening
hours...which will likely assist in regeneration through the late
evening...possibly into the early morning Thursday.
Severe thunderstorms continue into Thursday...though soundings
starting to transition to heavy rain threats. Long/skinny CAPE
profiles across southeast Wyoming with afternoon CAPE
1400/1500J/KG. PWATS up near 1 inch here at Cheyenne. Much higher
CAPE in the Panhandle with 2000-2500J/KG. May see heavy rainers
across southeast Wyoming and severe storms across the Panhandle
Thursday afternoon. HRRR/RAP simulated radar showing fairly
widespread showers and storms Thursday afternoon.
By 00Z Friday...layered PWATS well over an inch in the Panhandle
with close to 1.25 inch across our eastern row of Panhandle zones
to 1 inch westward to the I-25 corridor. GFS/NAM/ECMWF showing
pretty high 6 hour QPF Thursday night into Friday. Given high
PWATS and transitioning to long/skinny CAPE profiles...decided to
issue Flash Flood Watches for areas east of the Laramie Range.
This heavy rain will continue into Friday before upper trough
tracks to our south Friday afternoon. This should force the
widespread heavier rain east into Nebraska and Kansas...with drier
conditions late Friday afternoon.
.LONG TERM...(Saturday through Wednesday)
Issued at 300 PM MDT Wed Jun 28 2023
As the previous forecaster mentioned, the extended forecast remains
unsettled with daily chances for showers and thunderstorms. The
general upper-level pattern for the weekend and through early next
week has a ridge over the desert southwest with the CWA in more
northwesterly flow. This puts the region in a more favorable
environment for storms with the passage of numerous disturbances
aloft. By mid week, a deepening trough over Canada will push a cold
front south and through the CWA. Temperatures will likely cool off
for July 4th, but with increased chances for more widespread rain
and storms.
Although specific details for any day are still uncertain, severe
weather over the weekend and into mid week cannot be ruled out. A
quick look at deterministic models and model soundings do suggest
that Tuesday (July 4th) could be the best day for severe development
with dynamics at play from both a cold front and the location of a
250 mb jet streak. Of course, this is still about a week out so
models may change for the holiday!
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 538 PM MDT Wed Jun 28 2023
Clusters of thunderstorms will continue to push east into the
Nebraska panhandle this evening. Could see some low stratus
develop along the I-25 corridor later tonight through mid morning,
but most TAF sites will see another round of thunderstorms
tomorrow afternoon. &&
.FIRE WEATHER...
Issued at 300 PM MDT Wed Jun 28 2023
Dry and breezy across Carbon and Albany Counties this afternoon as
these counties are west of the frontal boundary that lays roughly
from the south Laramie Range...west to Rawlins this afternoon.
Laramie reporting wind gusts to 35 mph with 1PM humidity at 9
percent. North and east of the front humidity is well above
critical levels. This front will remain nearly stationary the next
24 hours or so...before finally dropping into northern Colorado
Thursday afternoon. Widespread showers and thunderstorms expected
to develop Thursday afternoon as humidity continues to increase
and interact with the mountains and the frontal boundary.
Widespread wetting rains...possibly heavy at times Thursday and
Friday could result in flash flooding of some ares that have
recently received heavy rainfall. Showers and storms begin to move
east late Friday with showers ending. With green fuels and
upcoming widespread wetting rains...fire weather concerns expected
to be minimal after this afternoon.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Flood Watch from Thursday afternoon through Friday afternoon for
WYZ101-102-107-108-119.
NE...Flood Watch from Thursday afternoon through Friday afternoon for
NEZ002-003-019>021-054-055-095-096.
&&
$$
SHORT TERM...GCC
LONG TERM...SF
AVIATION...REC
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Duluth MN
738 PM CDT Wed Jun 28 2023
.UPDATE...
Issued at 730 PM CDT Wed Jun 28 2023
A stratiform rain shield over the the greater Twin Ports and into
the Arrowhead region from today and this evening has resulted in a
saturated near-surface layer, which is expected through tonight.
The result is very low stratus only a few hundred feet above the
ground, and areas of dense fog. Visibility of less than 1/4 mile
have been observed on top of the hill in Duluth and further
southwest into Carlton County this evening. Forecast model soundings
from CAMs show what is expected to be a trapping of this moisture
into early Thursday morning, so periods of dense fog are expected
tonight for this part of the Northland. A Dense Fog Advisory is
now in effect for these rapid reductions in visibility within the
fog until 8 AM Thursday, covering the morning commute tomorrow.
Elsewhere, a few stronger thunderstorms may yet form in inland
northwest Wisconsin over the next few hours. Earlier rainfall and
cloud cover, along with a warm frontal boundary, are keeping the
most unstable airmass in the southern two-thirds of Burnett,
Sawyer, Washburn and Price Counties this evening. These areas
have the best chance at seeing an isolated severe thunderstorm
through Midnight tonight, with chances quickly decreasing from
west to east after that in our forecast area. A Severe
Thunderstorms Watch is in effect until 2 AM CDT for this threat of
that isolated severe thunderstorm chance producing large hail up
to 1" or wind gusts to 60 mph.
&&
.DISCUSSION...(This evening through Tuesday)
Issued at 253 PM CDT Wed Jun 28 2023
Summary: Showers and thunderstorms for the afternoon and through
the remainder of the week. Fog increasing overnight. Temperatures
will gradually warm through the week into next week.
Showers and thunderstorms are working their way through the region
this afternoon. Earlier concern was over NW WI as to whether or
not the sky could clear out in order to help increase instability.
This in fact has happened, therefore surface based CAPE is
1000-1500 J/kg, effective shear out of the west at 35 to 40 knots
increasing more towards the south. The current line will be moving
into the more unstable air this afternoon. Currently SPC has a
Slight Risk over the far southern portion of the CWA. Therefore
severe weather with large hail and an isolated tornado is possible
this evening.
The showers and thunderstorms have been as a result of an
shortwave that is moving through on the periphery of the high
pressure centered over central TX. This is expected to move
eastward/northeastward through time and ending any chances of
precipitation as it moves in southern Canada.
After the showers and thunderstorms move out of the area, fog is
expected to fill in overnight into the morning hours. Not
confident with a dense fog advisory, however it will be close in
some locations of dipping below a quarter of a mile. Elsewhere
added in smoke to the grids from the HRRR as smoke is expected
mainly over WI as an Air Quality Alert has been issued through
tomorrow afternoon.
Another upper level system will drop down into the region from
Canada for the remainder of the week. Additionally there will be a
cold front move through tomorrow morning. This will bring
isolated showers and thunderstorms to the region. Instability will
be limited and mid level dry air will prevent wide spread showers
and thunderstorms therefore not expecting any severe weather.
However, shear will be around 20 to 30 knots there can not rule
out small hail.
Temperatures struggled to warm up in areas of cloud cover topping
out in most locations in NW MN in the mid 60s. NE WI, however,
was able to warm up in to the mid 70s. Temperatures will rebound
over MN and NW WI tomorrow with highs in the upper 70s to low 80s.
Temperatures are expected to increase through the weekend with
highs in the mid to upper 80s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 641 PM CDT Wed Jun 28 2023
Numerous showers and scattered thunderstorms will continue across
the Northland terminals through 06Z Thursday. A few stronger
storms may produce hail and wind gusts to 50 mph at inland
northwest Wisconsin terminals in this time period. Overnight, the
ongoing IFR stratus across the region is expected to drop down
and create areas of fog, including much of the TAF sites. Have
kept only LIFR conditions for now, but terminal minimums may be
approached or exceeded for vis overnight due to dense fog. Will
keep an eye on conditions and drop vis more in amendments if
needed into tonight. Another round of thunderstorms is expected
for mainly northeast Minnesota, greatest coverage at the Iron
Range into the Borderlands, which includes HIB and INL.
&&
.MARINE...
Issued at 253 PM CDT Wed Jun 28 2023
Showers and thunderstorms will continue through the evening. Small
hail and cloud to water lightning are possible. Winds will be out
of the northeast at 10 to 15 knots with occasional gusts to near
20 knots. Waves will be 1 to 3 feet. Winds are expected to
decrease towards tomorrow morning. As a result waves will slowly
decrease to less than 1 feet by the afternoon. Isolated showers
and thunderstorms are possible again tomorrow evening. Small hail
and cloud to water lightning is possible.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 79 58 82 / 70 50 20 10
INL 58 75 56 78 / 40 80 30 50
BRD 61 84 59 82 / 10 30 10 0
HYR 58 83 55 83 / 100 50 20 10
ASX 58 81 57 82 / 90 30 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Dense Fog Advisory until 8 AM CDT Thursday for MNZ037.
LS...None.
&&
$$
UPDATE...NLY
DISCUSSION...KSE
AVIATION...NLY
MARINE...KSE
Area Forecast Discussion
National Weather Service Des Moines IA
651 PM CDT Wed Jun 28 2023
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Wednesday/
Issued at 233 PM CDT Wed Jun 28 2023
Key Messages:
- Low chance of storms with gusty winds, hail tonight
- Possible strong storm chances Thursday night into Friday and again
Friday night into Saturday
Details: Main concerns in the near term are the ongoing low
visibilities due to Canadian wildfire smoke and convective trends.
Early afternoon visibilities have improved about one to three miles
since around 8am this morning with current observations of 3 miles
or less well east of I-35. Current expectations based on trends and
latest HRRR smoke would have this pushing nearly out of the forecast
area, though it may linger and ebb and flow along the Highway 63
corridor into tonight. This low-level smoke should finally push out
by midday Thursday if not sooner. As a reminder, the Iowa Department
of Natural Resources Air Quality Bureau handles the air quality
monitoring, all aspects of air quality advisories, and is the point
of contact for any questions.
Beyond the smoke, elevated convection festered through the morning
into the early afternoon hours on the edge of the 12C 700mb
temperatures per SPC mesoanalysis and the veering, waning low level
jet. Iowa resides between the mid-level ridging over the southern
Plains with the top of this ridge over our region and an elongated
trough over Idaho up toward Manitoba. This puts our forecast area
under the shortwave troughs that will follow the top of the ridge
and keep intermittent storm chances in the forecast through
Saturday. The first could come later this evening, though confidence
is low given inconsistent convective allowing model (CAMs) runs and
questions of how much the elevated mixed layer may erode. 12z HREF
and CAMs that do generate convection would suggest formation over
central or southern Iowa with any convection traveling southeastward
along the instability gradient. Notable outliers were the 6z NamNest
and the 12z WRF-ARW which show a stronger, propagating MCS either
starting or entering our forecast area tonight. Any storms would
pose a risk of either damaging wind gusts or large hail given the
straight hodographs, but it is a conditional threat.
After any storms depart early Thursday, there should be a break
until later in the day when another shortwave trough will be pushed
over top of the ridge. This could spark an MCS crossing somewhere
over the state, perhaps favoring central or southern Iowa, with
favorable mid-level lapse rates and instability for wind and hail to
be a threat. Precipitable water values will be between 1.5 and 2
inches with favorable warm cloud depths. This could lead to heavy
rainfall, but given the progressive nature and dry antecedent
conditions not expecting any hydro issues. Any MCS would depart
Friday morning.
Next storm chances will come Friday night or Saturday as the
elongated trough that is presently over Idaho moves toward the
region. While not highlighted in SPC, CIPS, or CSU products, the
shear and instability on Saturday afternoon and evening could
support at least strong storms if not a few severe storms. As the
shortwave trough sinks east-southeastward away from the state on
Sunday, this should pull any lingering shower and storm chances out
of the state. This will be followed by the flow aloft transitioning
from weak northwesterly to westerly or southwesterly by midweek as a
more substantial trough drops out of Canada. While the higher storm
chances will likely be Wednesday or Thursday with the trough, will
be monitoring for any storm chances Monday and Independence Day. It
will not be an all day washout, but there could be some hit or miss
storms that could have an impact on outside activities either Monday
or perhaps moreso on Tuesday looking at ensemble guidance.
&&
.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 651 PM CDT Wed Jun 28 2023
Smoke continues to remain across the state, allowing for
visibilities to largely range between 4 to 6 statute miles at the
terminals. This smoke is expected to remain, especially over KMCW,
KALO, and KOTM through Thursday morning before improving. There
still remains a chance for KOTM to experience a storm or two after
03-06z this evening, and more scattered over the state Thursday
morning, though exact timing and location remains rather
uncertain. Will continue to closely monitor and make updates as
needed. Otherwise winds will shift after 06z throughout the
morning with a boundary passage from southeasterly to northerly.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Ansorge
AVIATION...Bury
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1201 AM EDT Thu Jun 29 2023
.AVIATION...
Greater dispersion of near surface smoke affording modest
improvement in the hazy visibility restrictions overnight. This
generally matches the projected trajectory offered by model forecast
output for the main plume of smoke to at least temporarily remain to
the south and west. Forecast will continue to highlight MVFR
restrictions overnight into Thursday morning, while keeping a close
eye on the response as winds turn variable or become calm. Smoke
density proving sufficient in areas to also contribute a ceiling,
now generally hovering near 4000 ft. Forecast outlook into Thursday
maintains some degree of hazy conditions, allowing for additional
expansion of the smoke plume back over lower Michigan. Some increase
in mid level cloud may commence Thursday as moisture funnels
downstream of nocturnal convection expected to organize over the
upper midwest. Remnant shower potential from this activity carries
low potential locally. Otherwise, generally dry low level
environment affords a broad coverage of sct to potentially bkn high
based VFR cu for the late day period. Continue to monitor potential
for more organized convection to impact portions of the area
Thursday evening into the overnight.
.DTW THRESHOLD PROBABILITIES...
* Low for cigs aob 5000 feet this evening.
* Low for thunderstorms late Thursday through Thursday night.
&&
.PREV DISCUSSION...
Issued at 323 PM EDT Wed Jun 28 2023
DISCUSSION...
NEAR TERM / REST OF TODAY THROUGH TONIGHT
As of 320 PM EDT...Weak surface high pressure continues to slide
eastward across the central Great Lakes this afternoon, with
gradually flattening ridging aloft moving in from the west. Dry
weather will prevail into early tonight as the high departs eastward
into the Mid-Atlantic. Passing high cloud and persistent thick haze
from the Canadian wildfires has kept high temperatures at bay in the
70s across the region, with highs generally expected to top out in
the mid/upper 70s.
The big story of the day has been the continued prevalence of thick
haze associated with the Canadian wildfires. Smoke continues to be
smelled at times at the surface as well, although trends into the
evening hours will be for the thickest haze to drift southward into
the northern Ohio Valley with improved visibilities especially north
of the I-94 corridor after 20z. However, latest smoke plume models
from the HRRR and Environment Canada suggest that as light northerly
winds flip southeasterly late this evening and into tonight, haze
will drift back northward across much of the region and with the
nocturnal inversion, visibility will likely decrease yet again. With
the continued persistence of the haze/smoke, EGLE has extended the
Air Quality Alert through Thursday. For more info on air quality,
refer to http://www.deqmiair.org.
Upstream tonight, northern stream energy dropping southeast out of
the Canadian Prairies into the upper Midwest will help initiate a
round of fresh convection invof MN/WI. This complex of thunderstorms
will move east/southeastward in quasi-zonal midlevel flow towards
northern Lower overnight, riding a burgeoning instability gradient
across the mid/upper-Mississippi Valley. Model guidance is in pretty
good agreement with a weakening trend towards early Thursday morning
as this activity gradually becomes elevated in nature and moves into
a less favorable moisture-rich environment. Given pattern
recognition, will at least place a slight chance PoP in for the Tri-
Cities late tonight to not completely rule out remnant
showers/rumble of thunder with convective debris clouds across the
remainder of the region.
Regarding fog potential late tonight into tomorrow morning, tricky
call given abundance of fog this morning, but cannot completely rule
it out given particulate matter aiding as a CCN contributor amidst
recent rainfall. Some negatives to fog though will be a stronger
gradient wind and continued spillover of convective debris clouds
from upper Midwest convection. Low temperatures in the mid 50s to
around 60.
SHORT TERM / THURSDAY THROUGH THURSDAY NIGHT
The Thursday convective forecast continues to carry a high degree of
uncertainty across southeast Michigan as there remains several
moving pieces that will ultimately determine whether southeast
Michigan sees strong to severe thunderstorms. Overall synoptic and
thermodynamic setup remain largely unchanged from the past 24 hours.
Moisture advection will be ongoing in earnest Thursday from the mid-
Mississippi Valley into the northern Ohio Valley and SW Lower
Michigan, with immediate areas west of I-75/US 23 on the fringes of
the best theta-e. Surface dewpoints will be in the process of
attempting to recover back into at least the lower 60s after 50s on
Wednesday, although low-level moisture transport vector orientation
will ultimately be determined by a potential MCS diving
southeastward from IA/IL tonight.
Should this moisture transport be largely unimpeded, a favorable
setup for strong to severe thunderstorms will exist across the upper
Midwest into the central Great Lakes. The nose of a strong
instability gradient will be pushing northward into the central Lake
Michigan basin, with MLCAPE building to 1500 J/kg as far north as
potentially GRR. Additionally, favorable midlevel lapse rates in
excess of 7 C/km will be in place across the region, with southeast
Michigan oriented at the nose of the best instability/moisture
gradients. Bulk shear continues to remain favorable as well at over
40 knots in the 0-6km layer, including 20-30 knots in the 2-4km
layer. However, capping concerns are in play, and with 700 hPa temps
approaching 10 C potentially pushing up as far north as the I-94
corridor heading into Thursday night, may hinder thunderstorm
development.
There continues to be a fair degree of spread amongst guidance in
convective initiation, timing of initiation, placement, and simply
whether convection happens at all. Taking it all in, hard to believe
given the environment setup that nothing will happen. Latest hi-res
runs have hinted at indications in initiation further north
somewhere across eastern WI, with a track into Lower Michigan and
portions of southeast Michigan. This scenario would be supported
further should a remnant boundary/mesoscale circulation emerge out
of the aforementioned northern stream-induced convection tonight
across the upper Midwest. Further south towards Chicago, capping
concerns come more into play, but several models continue to
indicate an explosive MCS developing by late in the day Thursday.
Given the proximity of the northern stream wave, and the favorable
positioning of the nose of the moisture/instability gradients, a
convective complex originating near central Lake Michigan and
tracking E/SE over much of the region / or developing overhead is
not entirely out of the question. Should this scenario occur, the
best timeframe would be after 00z Friday with damaging winds as the
primary threat. Depending on where initiation occurs, hail will also
be possible given initial discrete storm mode before quickly growing
upscale. Should a southern MCS solution arise closer to Chicago with
a track into northern Indiana, northern fringe thunderstorms that
may pose a severe risk could still be possible as far north as the I-
94 corridor. As mentioned in previous discussions, continue to stay
tuned and expect refinements given the complexity of the forecast.
LONG TERM / FRIDAY THROUGH TUESDAY
An active weather pattern looks to continue Friday and at least
through the first half of the weekend as a broad large-scale trough
lingers over the eastern Great Lakes. Scattered showers and
thunderstorms look to be possible during this time, with activity
aided by the diurnal cycle. Temps will be around normal in the low
80s with lows in the lower 60s.
MARINE...
Smoke persists over the waterways this evening with high pressure
now in place to the east. Weak gradient flow and lack of gustiness
keeps wave heights in-check over the next few days. Near-surface
smoke is now expected to persist into Thursday which maintains some
degree of visibility restriction, but confidence is too low to
warrant a Marine Dense Fog advisory. High pressure exits Thursday
evening ahead of inbound showers and/or thunderstorms as the pattern
becomes more active and unsettled into the weekend with multiple mid-
level disturbances. Any wave height or wind issues will be
localized, confined to any stronger storms that could develop.
HYDROLOGY...
A thunderstorm complex may move across southeast Michigan late
Thursday into Thursday night, although there continues to remain a
high degree of uncertainty. Should this scenario pan out, there will
be the potential for heavy rainfall associated with this system,
with quick rainfall totals approaching 1 inch in locales. Ponding of
water on roadways and minor flooding of urban areas and typically
prone areas may also be possible where the heaviest rainfall rates
and amounts occur.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&
$$
AVIATION.....MR
DISCUSSION...IRL
MARINE.......KGK
HYDROLOGY....IRL
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Goodland KS
950 PM MDT Wed Jun 28 2023
.UPDATE...
Issued at 812 PM MDT Wed Jun 28 2023
Increased pops given latest trends with widely scattered storms
ongoing across southern portions of the CWA. A little uncertain if
this will maintain its intensity once the sun sets. An additional
intense supercell is ongoing in Logan County Colorado and is
slowly moving ESE. Recent CAMS do suggest this moving into Yuma
County/SW Nebraska following the Bunkers Right Motion of the ESE.
RAP soundings show a favorable environment for severe weather
with the potential for 2 inch hail and 70 mph winds around 06Z.
The other change to the forecast as a result of this anticipated
convection was the fog potential has backed off as guidance is
favoring more stratus. The relative best fog potential looks to
be along and west of the CO/KS border from 09-13Z.
&&
.SHORT TERM...(This evening through Thursday Night)
Issued at 1255 PM MDT Wed Jun 28 2023
The remainder of this afternoon is forecasted to have most of the
area warm into the 90`s with locations south and east of a line from
Tribune to Norton potentially reaching the upper 90`s. Parts of
Eastern Colorado have been slower to warm with temperatures still in
the 70`s. Models also underestimated the dewpoints in Eastern
Colorado which have still been in the mid 60`s as of noon instead of
the mid to low 50`s.
With the high amounts of moisture remaining, there is a threat for a
few storms this afternoon and evening with a surface boundary south
of the area and a potential upper shortwave moving through. However,
similar to yesterday, the big limiting factor will be potential
capping. The cap could be stronger over Western portions of the area
where temperatures may not warm as much as guidance was suggesting
due to early morning fog and higher moisture available over the
area. This will affect the potential for storms later this evening
for areas near and north of the Tri-State border. Guidance has
suggested that storms could form in Northeastern Colorado (ahead of
the shortwave and along the higher terrain) and move east across
northern portions of the Tri-State area. But if the cap remains in
place, any initial development would struggle to form and then
maintain itself into the area. Otherwise, it would be possible for a
few supercells to move across and produce damaging hail and winds
for counties generally along the Nebraska border. The other chance
area is for counties in Northwestern Kansas along and south of I-70
this afternoon and evening. Satellite shows a line of clouds along a
surface boundary around Southwestern Kansas and Southeastern
Colorado. If storms form along or ahead of the boundary, they may be
able to move northeast into parts of the Tri-State area. Given the
current position of the boundary, storms would likely need to fire
closer Pueblo given the mean motion to the northeast would mean
anything starting further south and east may miss the area.
Tonight, skies will remain partly cloudy and winds shift to out of
the east. With the easterly winds, fog will be possible depending on
how moist the area remains and how much clouds hinder cooling. Lows
will remain the 60`s for most of the area. If fog does develop, may
need to watch for some patchy dense fog. Guidance is suggesting that
the favored area would be similar to last night, east of Highway 83.
For tomorrow, slightly cooler temperatures are forecasted with some
slight cold air advection aloft lowering our 850mb temperatures in
the 20`s. Some additional cloud cover and lingering moist conditions
will also keep temperatures slightly cooler. How much cooler is a
bit uncertain given the lack of an air mass change. But temperatures
in the 80`s and 90`s remain likely with the warmer temperatures
generally east of Highway 83. If cooler air did advect in, most of
the area would stay in the 80`s.
Storms are forecasted to move through the area again tomorrow
afternoon and evening as the upper trough that has been over the
west moves closer to the area. With the increased synoptic forcing
of both the upper trough and a surface low just south of the area,
higher chances and coverage for storms are expected. There could be
severe weather as well with large hail and damaging wind gusts given
MLCAPE around 1000-2500 J/KG, effective shear around 45-50 kts and
DCAPE greater than 1200 J/KG. Storm should move from west to east
across the area as the trough moves through from west to east. The
hail threat will likely be highest with initial storm development in
Eastern Colorado and then slowly transition to more of a linear
storm mode and wind threat.
.LONG TERM...(Friday through Wednesday)
Issued at 1251 PM MDT Wed Jun 28 2023
12Z Friday the area is under southwesterly flow aloft with the upper
trough axis centered over the Four Corners region. This will
gradually move east, and bring shower and storm chances to the area.
The WPC has included the Tri-State Area in a marginal risk for
excessive rainfall on Friday. Afternoon high temperatures are
forecast to be in the middle 70s to middle 80s with overnight low
temperatures in the middle 50s to lower 60s.
Into Saturday, high pressure builds over the western CONUS while the
upper trough over the plains progresses eastward, leaving us under
northwesterly flow aloft. We`ll see some continued storm chances as
the trough begins to exit the area. Temperatures continue in the
middle 70s to middle 80s for highs and middle 50s to lower 60s for
lows.
Drier weather is anticipated to start the week as the upper ridge
moves overhead. Weak disturbances within the flow however may bring
some spotty afternoon-evening showers/storms. Temperatures will
start to warm back up into the middle 80s to lower 90s Sunday, then
middle 80s to middle 90s Monday with overnight lows in the middle
50s to middle 60s.
A trough dipping south into the northern CONUS around Tuesday-
Wednesday, July 4th-5th may provide better focus for storms.
Temperatures climb into the middle 80s to middle 90s for the 4th and
upper 70s to lower 90s on Wednesday. Lows will be in the mid to
upper 50s to mid to upper 60s.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 942 PM MDT Wed Jun 28 2023
Complicated first few hours of this TAF period as a cluster of
severe storms is located across northeast Colorado. Guidance is
struggling with the evolution of these storms. Confidence as of
now is high enough to leave any thunder mention out for KGLD as
the relative better agreement is for KMCK to be impacted between
06 and 08Z. These storms will more than likely be severe with
large hail up to 2 inches and the potential for greater than 50
knot winds. I did leave the winds sub severe for this TAF period
as there has not been any wind reports thus far. The potential
still does exist for at least MVFR ceilings and visibilities due
to stratus and fog at KGLD, but the overall evolution of these
storms may throw a wrench into that potential. More showers and
storms are possible Thursday but coverage and location at this
time is to low to include in the TAF.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...Trigg
SHORT TERM...KAK
LONG TERM...CC
AVIATION...Trigg
Area Forecast Discussion
National Weather Service Grand Rapids MI
802 PM EDT Wed Jun 28 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 758 PM EDT Wed Jun 28 2023
Based on the webcams and HRRR smoke forecast, we extended the
Advisory over the nearshore waters through Thursday morning.
Otherwise the forecast was left unchanged. Showers and
thunderstorms are projected to develop across WI this evening into
tonight and then roll toward western parts of the CWA around 10 to
14z Thursday. This is the region where we have the highest POPs so
we will keep it that way.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 314 PM EDT Wed Jun 28 2023
Smoke continues to linger across parts of West Michigan, though some
improvement has been noted over central Lower Michigan the past few
hours. As ridge of high pressure moves east of the area tonight,
winds will becomes SE, and this should prevent the somewhat more
pristine air to the north from advancing significantly farther south
through lower Michigan, and as a result forecast will continue to
include areas of smoke through Thursday.
Otherwise, attention turns to potential for (still much needed)
showers and storms, as weak front/trough currently extending from
Minnesota to eastern Nebraska moves east tonight, weakens further,
and effectively stalls across the region. Models have trended more
bearish on precipitation chances, and this seems reasonable given
LLJ characteristics, lack of rich moisture in advance of low level
forcing, and meager forcing aloft.
Forecast will reflect small chances for showers and perhaps
thunderstorms over NW parts of forecast area late tonight (after
08Z), and then over all areas Thursday and Thursday night. Any
diurnal bump in shower coverage Thursday will be a function of
boundary location/interactions and ability of atmosphere to
destabilize under weakly anti-cyclonic flow aloft. Chances for
significant wetting appears low. Low temperatures around 60
tonight will rebound into the 80s Thursday.
.LONG TERM...(Friday through Wednesday)
Issued at 314 PM EDT Wed Jun 28 2023
The long term portion of the forecast will generally be quite warm
and humid, with a few small chances for rain. The best chances for
rain will be across the southern portion of the area.
We will see a neutral upper air flow pattern in place on Friday.
The cyclonic side of the upper jet will be north of the area up in
Canada, while the ring of fire along the periphery of the ridge
is expected to stay to our south. Rain chances on Friday will be
quite low, and focused mainly to the east, with the departing wave
of showers/storms. Can rule out something firing in the afternoon,
but it should be mainly east of our area along the Lake Huron lake
breeze.
There is not really a solid feature that will be affecting the
area on Saturday. Most of the area should remain dry, but some
diurnal instability present with temps well into the 80s and dew
points well into the 60s will provide sufficient fuel for a pop up
shower/storm Saturday afternoon. There seems to be a convergence
zone showing up across the eastern portions of our area where lake
breezes from Huron and Erie would collide with the westerly
synoptic flow.
The best chance of rain at this time in the long term looks to
come on Sunday across the far southern portion of the area. The
upper flow will absorb a low/trough over the Rockies, and bring it
across the region. The best forcing with this feature moving
through will be across the south, closer to the sfc low and better
mid level vorticity. The majority of the shower/storm activity
will stay south of our area, but could clip our southern counties.
It will have the instability to work with the 80s sfc temps and
60s dew points still.
Once the Sunday feature moves out, we are looking at a better
chance of completely dry conditions holding through the holiday
and into mid-week. We will be seeing upper ridging build over the
area in the wake of the departing Sunday trough, and ahead of the
digging trough over the Upper Midwest. We will be slightly cooler
behind the Sunday trough, but will warm up again as the ridge
builds.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 730 PM EDT Wed Jun 28 2023
Thunderstorms are predicted to develop over in WI this evening
and then roll towards southwest Lower MI later tonight into early
Thursday. Most indications are that the storms will only clip the
region as they curve southeast towards the southern end of Lake
MI. KMKG has the highest potential to see a thunderstorm in the
vicinity and around 12z is the period of greatest risk. I
therefore added thunder to the KMKG Taf then. Further inland the
threat for a morning storm is lower, but trends will be important
to monitor. I have not added thunder to the inland locations at
this time. How much if any storms we see during the remainder of
Thursday depends on how the storms develop tonight. It does become
unstable during the day so there is a risk, but confidence on the
timing and location was too low to add thunder to the remainder
of the period.
Smoke will continue at the TAF sites into Thursday morning with
several models suggesting a possible increase tonight. Given the
mainly MVFR coverage around the area, we will mostly hold onto
that through the night. KMKG has seen IFR and based on the model
forecast it looks like it may struggle to increase to MVFR
tonight. Overall with a south to southwest flow developing on
Thursday, by afternoon the smoke should be lifting north of the
TAF sites. We therefore feature conditions trend to VFR then.
&&
.MARINE...
Issued at 314 PM EDT Wed Jun 28 2023
Dense Smoke Advisory will continue for marine areas into early this
evening, given area webcams, and per previous coordination with
IWX/LOT/MKX. Otherwise, winds and waves will remain on modest.
Largely variable winds this afternoon will become SE tonight as high
pressure moves just east of the area, and then increase slightly out
of the SSE on Thursday -- but below SCA and Beach Hazard
thresholds.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Dense Smoke Advisory until 1 PM EDT Thursday for LMZ844>849.
&&
$$
UPDATE...MJS
SHORT TERM...Smith
LONG TERM...NJJ
AVIATION...MJS
MARINE...Smith
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
742 PM CDT Wed Jun 28 2023
.SYNOPSIS...
Issued at 742 PM CDT Wed Jun 28 2023
Smokey skies from Canadian wildfires will continue through
tonight, and possibly into Thursday. However, storms and winds
becoming more southwest tonight into tomorrow could push the smoke
out sooner, but we will have to wait and see. Some storms are
expected to move in tonight from the northwest, followed by hot
and humid conditions tomorrow. Temperatures in the mid 90s and
dewpoints in the lower 70s will result in heat indices in the 100
to 105 degree range by tomorrow afternoon.
&&
.UPDATE...
Issued at 742 PM CDT Wed Jun 28 2023
Main concerns in the short term remain with the smoke and rain
chances.
Smoke:
Surface obs are showing some relief from the thick smoke/haze is
edging into areas toward Jacksonville, with visibility up to 5-7
miles in the southwest corner of the forecast area. 18Z run of
the HRRR Smoke model shows little progress eastward past midnight,
with the greatest concentrations focusing more from Galesburg-
Effingham eastward. However, a more substantive northward shove
in the smoke takes place toward sunrise. Air quality alert remains
in effect into Thursday, and no changes are expected at this
point without consultation with the Illinois EPA. However, their
forecast does show conditions "improving" to orange (unhealthy for
sensitive groups) for the entire CWA for Thursday.
Rain:
A few showers and thunderstorms persist early this evening near a
weak surface boundary that extends from just west of Peoria to
near Shelbyville. This is likely to fade with sunset, and PoP`s
for mid to late evening have been removed. The challenge is with
development off to our west. Not much being seen upstream in terms
of cumulus development at this point, and the 18Z NAM-4km appears
to be overdoing it. HRRR develops some convection near
Peoria/Springfield toward 2 am and brings the main MCS in after
sunrise. Experimental RRFS from 18Z doesn`t go out quite far
enough, but suggests a distinct break between the two clusters and
keeps areas from Springfield westward dry through the night.
Confidence is not especially high at this point, but will lean
toward the HRRR/RRFS solutions with the highest PoP`s late tonight
into early Thursday morning.
Geelhart
&&
.SHORT TERM... (Through Late Thursday Night)
Issued at 343 PM CDT Wed Jun 28 2023
Scattered showers and isolated thunderstorms will continue to move
across the area this evening with a little bit of qpf expected.
However, a more complex situation will set up tonight through
tomorrow night with a sfc boundary extending from western
IA/eastern NE, across IA into IL. Warm moist air south of this
boundary across MO should interact with the boundary later
tonight, with a large storm complex developing on the nose of the
low level jet somewhere over IA. These storms will ride along and
north of the boundary to the east and possibly southeast into IL
late tonight and through tomorrow morning. The CAMs are similar
with this scenario, but different on timing and location of where
the storms will move across IL. Due to the timing and location
differences, forecast confidence is probably running about 50% at
this time. Current forecast has chance pops of rws tstms tonight
through tomorrow, but may need to be raised to likely later
tonight. Tomorrow afternoon through evening, there should be a lag
in the precip, but additional showers and storms are possible
again late tomorrow night as the weather pattern will be similar
to what is expected tonight.
Overnight lows are expected to be around 70 tonight and tomorrow
night. Temps are expected to be quite warm tomorrow as well as the
area will be in the warm sector. Highs will be in the mid 90s with
dewpoints in the lower 70s, resulting in heat indices in the 100
to 105 degree range. The current heat advisory for our southeast
three counties will remain in place for tomorrow and no addition
is planned at this time.
CAMs that have smoke parameters suggest the smokey conditions will
wane later tonight and through tomorrow. Based on the expected
weather and winds switching to southwest, this seems reasonable.
However, for now, will not make any changes to our current Air
Quality Alert for the entire area.
Auten
&&
.LONG TERM... (Friday through Next Wednesday)
Issued at 343 PM CDT Wed Jun 28 2023
With the weather pattern remaining more zonal into the weekend,
multiple periods of showers and storms are possible. However,
details like timing, locations, and amounts are hard to forecast
at this time. What happens through Thurs night will play a big
role in what things look like for the weekend and possibly into
next week. Precipitation does look likely Fri night through Sunday
based on the current extended model forecasts. A fine tuning of
this forecast can be expected as we get closer to the weekend.
Temps will be warm on Friday, but lots of clouds and precip will
bring temps down for the weekend. However, not expecting this to
last as hot temps return next week with highs returning back to
the lower 90s.
Auten
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 607 PM CDT Wed Jun 28 2023
Widespread IFR visibilities continue early this evening due to
smoke at the surface. HRRR smoke guidance suggests KSPI may see
some decent improvements this evening, but a more wholesale
increase to VFR over central Illinois is probably more likely
toward 09-12Z. By that time, clusters of showers/storms may still
bring reduced visibilities. Coverage and timing of the storms is
somewhat uncertain at this point, so a mention of VCTS will
suffice. Confidence wanes further after about 16-17Z, and will not
mention thunder Thursday afternoon yet.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 10 AM Thursday to 6 PM CDT Friday for
ILZ071>073.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Indianapolis IN
925 PM EDT Wed Jun 28 2023
.Forecast Update...
Issued at 925 PM EDT Wed Jun 28 2023
Our previous thinking with regards to convective potential
tonight generally remains the same. Models show a fairly strong
low-level warm/moist advection scenario tied to a transient
midlevel shortwave trough on the periphery of mean ridging
centered to our southwest. By the predawn hours, a plume of lower
tropospheric moisture seen now in CIRA satellite layered moisture
products will likely be substantial enough to initiate convection
across eastern Illinois. This warm/moist advection and isentropic
ascent is occurring beneath relatively steep midlevel lapse rates,
resulting in fairly strong instability for elevated parcels, but
the instability gradient is tight.
Convection will likely initiate on this gradient in eastern
Illinois on the convergent leading edge of low-level jet. Mean
cloud-bearing wind suggests southeastward forward propagation, but
with some southward component owing to a modest low-level jet and
resultant upshear propagation that would result. This should keep
the most robust convection and heaviest rainfall amounts across
roughly the southwest third of the area. The northern end of the
downstream propagation deeper into central Indiana may be limited
by the aforementioned instability gradient which may effectively
stall due to significant convective overturning. Thus, for now, we
will keep precipitation probabilities mid-range further east in
central Indiana late tonight through early morning, and will
adjust based on observational trends. It`s possible that
convection is delayed and/or confined enough that the warm/moist
advection regime penetrates deeper into Indiana before propagation
takes root effectively shifting convection more southward.
It`s worth noting that these scenarios where interaction of
multiple mesoscale components dictate convective growth and
behavior, CAMs can struggle some. Hence, the diversity of
placement/timing seen in the current suite of CAM guidance.
Furthermore, the character of the first round of convection will
dictate the behavior of subsequent rounds. Regardless, with a
warm/moist advection regime helping drive instability upward and
perturbations within westerlies aloft, as some point most of the
area will see convection but the snowball or domino effect lead to
a higher than normal level of uncertainty with regards to
coverage and timing over the next couple of days.
Our greatest concern with the thunderstorms late tonight into
early tomorrow is heavy rainfall amounts and flash flooding,
especially if there is a period of training before upshear
propagation takes hold. The few CAM members that show this
evolution (i.e., HRRR) have concerning amounts in our far
southwest counties. At this time, this is a low probability but
plausible scenario. On the other end of the spectrum of
possibilities, some CAMs are more aggressive with cold pool
growth and sufficient shear for a forward propagating MCS deeper
into central Indiana during the early morning hours. The
thermodynamic/kinematic environment isn`t particularly favorable
for an accompanying damaging wind episode and this scenario would
likely outpace the instability axis limiting convective intensity.
Nevertheless, strong to marginally severe gusts seem possible in
the reasonable worst case scenario.
&&
.Short Term...(This evening through Thursday)
Issued at 235 PM EDT Wed Jun 28 2023
Observations across the region continue to show significantly
reduced visibilities as low as 1 mile as of 2pm. Not much
improvement has occurred so far today, and satellite shows a large
area of wildfire smoke lingering from Illinois, to southern
Michigan, into Indiana and Ohio. As such, am inclined to be a bit
more pessimistic regarding air quality and visibility through
tonight. Smoke plume models show improvement late tonight,
thankfully, as a warm front advancing from the south will allow
cleaner air to filter in. Will keep smoke and haze in the forecast
through 12z.
The main challenge of the short term will be convective potential
overnight. Most guidance shows some kind of development occurring
well after midnight west across Illinois. A few questions remain
regarding this activity, however. First, which locations are most
likely to see such convective activity? And second, should
convection occur, what form will it take and how will it evolve?
Finally, what are the main convective hazards and timing?
We will start by examining the larger-scale pattern. Aloft, a ridge
centered over Texas will allow for a strong anticyclonically curved
jet to skirt across the northern tier of the CONUS. Our position
relative to the ridge axis places us within northwesterly flow
extending from 250mb down to 700mb. In the lower atmosphere, south
to southwesterly flow dominates...leading to warm moist advection to
our west. The warm front is expected to lift northward tonight, with
an unstable air mass behind it. An instability / theta-e gradient in
turn sets up northwest to southeast across northern Missouri into
Illinois. Such an environmental setup is conducive to the "ring of
fire" effect as upstream convection rides the jet southeastward and
is fueled by the warm moist advection. Indeed, almost every model
shows some kind of MCS developing upstream and propagating towards
Indiana. One problem, however, is each model is wildly different in
terms of timing, location, and other fine-scale details.
Given the large-scale pattern at hand, we are confident that
convective activity will occur across the region tonight into
tomorrow. However, confidence begins to decrease when trying to
determine exact placement of convective systems and their potential
paths. This brings us back to our first question, most guidance
shows convective initiation around 06z-09z occurring in Illinois
along the warm front as isentropic lift and a shortwave interact.
This convection then is modeled to grow into a convective system and
drift east-southeastward. Exactly where initiation occurs will
determine who sees the brunt of this activity overnight. Given a
loose model consensus of Illinois initiation, it would appear that
areas south and west of Indianapolis stand the highest likelihood of
thunderstorm activity later tonight.
Now to our second question...as briefly mentioned, convection should
organize into a convective complex. Model soundings show relatively
dry low-levels which should allow for quick cold pool development.
Strong northwesterly shear with southeasterly surface winds should
allow for some cold pool shear balance for system maintenance.
Strong LLJ from the southwest will feed in moist unstable air
causing the system to preferentially propagate with a southerly
component, perhaps more than CAMs show. Therefore, take model
reflectivity with a grain of salt. With that said, expect initial
convective cells to move east, before congealing into an MCS and
moving more southeast or even due south depending on how the theta-e
gradient sets up.
Finally, what are the primary convective hazards? Model soundings
again show dry air in the low to mid levels, which could lead to
strong gusty winds. Should a cold pool become established and a rear
inflow jet form, then any bowing segments could pose a risk for
severe wind gusts. Additionally, initial discrete activity will pose
a large hail risk as ample shear, CAPE, and steep lapse rates exist
within the hail growth zone (HGZ). Furthermore, increasing flow from
the HGZ to cloud tops will allow for sufficient cloud top venting.
Model soundings show a steep low-level inversion, which should not
impede wind gust potential as it is shallow and warmer than
potential downdraft temperatures.
Temperatures are expected to be warmer tomorrow as the warm front
advances into the region, along with less smoke. Lingering clouds
from morning convection could disrupt the diurnal temperature curve.
Highs in the upper 80s to low 90s are expected with much more humid
conditions. Synoptically-driven winds should remain under 10kts
tonight, before increasing to 10-15kts Thursday morning as MSLP
gradients tightens. Winds then drop off later on Thursday as the
gradient relaxes a bit.
&&
.Long Term...(Thursday night through Wednesday)
Issued at 235 PM EDT Wed Jun 28 2023
- Active Weather Pattern setting up for Thursday Night through
Monday
- Shower and Thunderstorm chances are expected to persist each day
through Monday
- Better chances for dry weather on Tuesday and Wednesday
Thursday Night and through Saturday...
The upper pattern suggests high pressure aloft over the deep south
and low pressure in place over Ontario. This will allow for a stream
of Pacific air combining with gulf air wrapping around the high
pressure system to the south to flow across Illinois and Indiana.
Several short waves embedded within this flow are suggested to pass
starting on Thursday night through Saturday. Another feature that
appears to be present on Thursday Night is a thermal ridge that the
models show surging across southern Illinois and southern Indiana,
creating a temperature gradient across Central Indiana. Forecast
soundings through this period suggest conditions that appear
favorable for convection, with plentiful CAPE in excess of 2000 J/kg
each day with attainable convective temperatures. Pwats in excess of
1.5 inches of up 2 inches will be in place through the period also.
Vertical wind profiles also show favorable conditions veering winds
with height. The previously mentioned upper pattern will help
provide a bit of tighter gradient aloft also, supporting stronger
winds aloft and along with that, the possibility of stronger storms.
Timing of these waves will be difficult per the evolution of each
convective system, but latest timing shows best forcing arriving
Thursday Night, Friday afternoon and Friday Night. There will still
be many dry hours over the next several days but chances for rain
will be needed throughout these periods as these waves pass.
Given the winds aloft, available instability and favorable wind
profiles, all types of severe weather may be possible over the next
few days. Better confidence will arrive each day as models have a
better handle on the evolution of each system.
Sunday and Monday...
An upper trough over the Great Lakes is expected to sag south
through the Ohio Valley on Sunday and Monday, changing the weather
pattern slightly. The waves of forcing dynamics from the west and
south will be more limited but still be persistent through these
days. However the previously mentioned gradient will no longer be in
place. Thus chances for severe storms will appear to be a bit more
limited. Forecast soundings on these days suggest a column still
capable of precipitation and thunder, although CAPE appears to be a
bit more limited with values ranging less than 1500 J/KG as the
upper trough axis is suggested to pass Sunday Night into Monday.
Lower level flow looks to remain southerly until the associated
surface low passes on Monday afternoon. This should keep a warm and
moist air mass in place across Central Indiana. Thus again pops will
be needed each day, with best pops expected on Sunday Night and
Monday as the upper trough axis and surface low passes.
Tuesday and Wednesday...
Weak ridging extending from the Central Plains toward the Great
Lakes is suggested to build across the area for Tuesday and
Wednesday. This should bring about subsidence and weak surface high
pressure is depicted to be pushing through the Ohio Valley. Thus dry
weather will be expected for now in the middle of next week
Temperatures through the period are expected to remain quite
seasonal, with highs in the 80s and lows in the 60s. Upper 80s to
around 90 will be possible on Wednesday as return flow from the
departing surface high will be ongoing.
&&
.Aviation...(18Z TAF Issuance)
Issued at 456 PM EDT Wed Jun 28 2023
Impacts:
* IFR to MVFR visibility expected through the night
* Scattered showers and possibly thunderstorms after 08z
Discussion:
Winds may be calm, or light and variable for a time through tonight,
but should generally trend more southeasterly for the rest of the
TAF period.
Wildfire smoke from Canada will continue to result in at least MVFR
visibility through the night and early tomorrow. Mechanisms to
displace this smoke may be heavier rain showers/thunderstorms at
least briefly improving visibility. Otherwise, low level
trajectories will trend southeasterly and could improve visibility
slightly based on upstream observations, but HRRR smoke model
suggests residual smoke will likely have at least some impact to
visibility into tomorrow. Thus, we have already extended the
IFR/MVFR visibility into tomorrow morning and may have to extend
lower visibilities further in time. Confidence on a return to VFR
visibility toward the end of the TAF period is low at this time.
There are clouds present at the moment from a weak midlevel
perturbation moving through, but these are generally mid-level
clouds or higher (ceilings around 10,000 ft). MVFR ceilings
indicated on most METARs is due to smoke and so we have vertical
visibility rather than OVC/BKN to better convey the obscuration.
Another uncertain part of the forecast is shower/thunderstorm
potential. Timing may need to be shifted and we may need to increase
a period of the TAF at most sights to TEMPO or prevailing once
confidence increases. Once we feel more confident about the
evolution of convection later tonight through the morning we will
amend as necessary.
Overall, low confidence forecast with several impactful elements to
aviation possible.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...BRB
Short Term...Eckhoff
Long Term...Puma
Aviation...BRB
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1022 PM EDT Wed Jun 28 2023
.UPDATE...
Issued at 1022 PM EDT WED JUN 28 2023
The NBM continues to trend cooler for Thursday, with more
widespread mid- to upper-80s than the upper-80s to lower-90s the
afternoon package had. This lends higher confidence to the NBM
trend of increasing the cloud cover for the mid-morning through
mid-afternoon period. There are no other changes otherwise.
UPDATE Issued at 729 PM EDT WED JUN 28 2023
Made some minor changes to the grids, including adding haze from
smoke to the grids using the HRRR-Smoke model.
Big question for Thursday remains timing and location of
potential convection across the forecast area late Thursday
morning into mid-afternoon. Various 12z CAMS seem consistent in
brining a south-southeast moving MCS across central and southern
Kentucky along and west of Interstate 75 Thursday, but with
timing varying from as early as mid- to late morning to as late as
early to mid-afternoon. The latest NBM, used for this early
evening update, does slightly lower maximum temperatures and does
increase cloud cover during the late morning through mid-afternoon
period, which suggests perhaps slightly higher (though still low
overall) confidence amongst ensemble members that make up the NBM
that there will be some convective activity impacting parts of
eastern Kentucky during that time.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 305 PM EDT WED JUN 28 2023
Key Messages:
-Uncertainty remains on storm chances through the short-term
period.
-Potential for heavy rainfall and even gusty winds with some of
these storms.
The afternoon surface analysis shows an area of high pressure
continues to push across the Ohio Valley and Great Lakes region
this afternoon. The flow around this high pressure has brought in
smoke from Canadian wildfires today, and the Kentucky Energy and
Environmental Cabinet did opt to hoist an Air Quality Alert
through midnight tonight. We will see some improvement in the
smoke through the night based on the HRRR smoke product. The
question tonight will be whether there are clear skies or more
cloud cover, as well as what happens with overnight convection.
All this said, we opted to keep fog in the valleys overnight,
which could be locally dense depending on extra particulates from
the smoke. The lows in the valleys will drop into the upper 50s
and lower 60s on the ridges. Later tonight into early Thursday
morning, some convection could slide across parts of the Lake
Cumberland region, with around a 20 percent chance at this point.
On Thursday, the previously mentioned surface high pressure will
push into the mid-Atlantic, which will lead to increased moisture
under southerly flow. The latest HREF mean PWATs will rise above 1
to nearly 1.5 inches by tomorrow afternoon. There could be some
left-over upstream convection early in the day, mainly in the Lake
Cumberland region. This is where some uncertainty comes in, as we
remain on the periphery of the upper level ridge and the quote
ring of fire territory. Therefore, we opted to increase PoPs
through the afternoon into the slight chance range (around 15–20
percent). The biggest issue with the convective coverage for
tomorrow is the strong capping inversion around 850mb that could
be hard to overcome, but it all depends on outflow and other
lifting mechanisms. SPC does have parts of eastern Kentucky
(mainly the Lake Cumberland region) at a 2 out of 5 risk for
severe weather, but even in their discussion, there remains quite
a bit of uncertainty with the evolution of the convection. The
afternoon highs will depend on convection, but the upper 80s to
lower 90s seem reasonable.
Thursday night, some of the guidance had a mid-level wave pushing
across the Ohio Valley, but the placement of this feature
remained quite different. Given this, we opted to lean on the NBM
solution in a larger ensemble mean approach for PoPs, and this
leads to around 40–50 percent chances of rain right now. If this
does occur, we will likely see some thunderstorms given the more
than ample MUCAPE or more elevated CAPE at around 1000 J/kg or
more based on the HREF mean. These would be able to produce brief
heavy rainfall too, given the time of day and ample PWATs of
around 1.5 inches.
.LONG TERM...(Friday through Wednesday)
Issued at 258 PM EDT WED JUN 28 2023
Key Points:
* Waves of showers/storms possible at times Friday through Saturday,
some of which could be strong or severe.
* Warm and muggy air will push heat indices to around the 100 degree
mark Friday and Saturday, but will largely depend on cloud cover
and any convection that occurs during each day.
* Approaching cold front allows for numerous showers or storms
Sunday, with scattered chances remaining in the forecast through
early next week. Temperatures to be around seasonal norms during
this time.
The period will begin unsettled and warm. Stout ridging will now be
centered across the ArkLaMiss region, where Eastern Kentucky will be
sandwiched between the periphery of the feature and a swinging
trough from Southern Ontario. This will allow a corridor of upper
vorts to pivot through and induce bouts of showers and storms.
Guidance has been quite shaky in the depiction of these waves, where
convection will primarily be driven on meso scale features
(MCS/outflows/subtle boundaries/ etc). Because of this, guidance is
not handling this well, and thus why so inconsistent. This leads to
low confidence during the Friday through Saturday period, before
better agreement in the approach of a cold front Sunday. Given the
upper level pattern and set up, an MCS or two seems probably, with
the best chances during the afternoon to early overnight hours. The
first of these could be into the start of the period, with
redevelopment possible Friday afternoon to evening. Soundings depict
plenty of instability (2500-3000 J/kg+) and EBWD marginal between
20-30kts. This is also backed by notable values within the
Extreme Forecast Index for CAPE. If any convective complex or
orographically induced storm(s) materialize, and passing waves
influence the ~800mb capping, strong to severe storms could be
possible. Strong to damaging wind gusts are the primary threat,
but marginally large hail will also be possible.
Additionally, temperatures will be seasonably warm through the first
half of the weekend. As the upper ridge expands further east, across
the Lower Mississippi Valley and Deep South, and the surface high
shifts out of the region, better moisture advects in off the Gulf.
PWATs of 1.75-2" (at least a SD above the norm) will advect in,
where td`s will range in the low to mid 70s. Combined, this will
equate to feel-like temperatures in the upper 90s to low triple
digits. That said, any cloud debris from remnant systems, afternoon
cu, or on-going convection could hamper higher afternoon values.
Ensembles also suggest NBM values continue to come in too hot. With
the mentioned uncertainty above and 90th percentiles in the 95
degree ballpark, have cut back suggested blend data to the lower 90s
overall Friday and upper 80s to low 90s Saturday.
Numerous showers and storms are then expected Sunday with the
approaching cold front, where the residence time of the trough
pulling east out of the area will be slow. As a result, rounding
shortwaves and the nearby surface boundary will keep scattered
shower/storm chances in the forecast through the end of the period.
Activity will peak primarily in the afternoon to evening hours each
day, with temperatures overall during this period around seasonal
norms (mid 80s).
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 729 PM EDT WED JUN 28 2023
MVFR mainly vis restrictions from upstream wildfire smoke this
afternoon. This smoke and haze will remain in place through this
evening, but a combination of fog and haze will continue to lead
to some restrictions at times through the night. Under high
pressure we will see light winds through the period.
For the second half of the TAF period, we used a blend of HREF
cloud cover and the max ensemble of 1-hr precipitation to bring in
increased cloud cover from northwest to southeast across the
forecast area after 12z, with just enough confidence to warrant
inclusion of VCTS at KLOZ and KSME during the morning through
afternoon period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CMC
SHORT TERM...DJ
LONG TERM...BB
AVIATION...CMC
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
910 PM CDT Wed Jun 28 2023
.UPDATE...
Issued at 902 PM CDT Wed Jun 28 2023
A broken line of convective showers and light thunderstorms is
moving across a rather narrow corridor in central Illinois this
evening. These elevated showers appear to be originating on the
leeward side of a deamplifying shortwave trough positioned over
southern Iowa evident in the 700mb wind field. Latest RAP data
suggests the environment out that way features a good deal of
elevated instability and a potent little vort lobe embedded within
the wave. However, these showers are struggling to maintain
themselves as they progress into central IL where instability and
forcing both drop off rather quickly. Thus far, very little rain has
been able to make it to the IL/IN state line before fizzling away.
While this line in particular isn`t expected to amount to anything
that will impact our area, the aforementioned wave will likely play
a role in thunderstorm chances overnight as the surrounding
environment becomes more favorable for elevated convection.
Efficient moisture and warm air advection taking place aloft is
expected to readily destabilize the atmosphere and steepen up mid
level lapse rates through the rest of the evening. The RAP also
suggests that isentropic upglide and vertical moisture transport are
beginning to ramp up from west to east across the region through
roughly an 800-600mb layer which will further aid in destabilizing
the environment aloft. Additionally, a vort stream leftover from the
aforementioned wave is progged to stretch across central IL through
the night. After a few good hours of priming yet, recent CAM
guidance is in fairly good agreement on a cluster of elevated
showers and thunderstorms firing up and moving across central IL
shortly after midnight. That being said, the better rain and storm
chances overnight, at least with this disturbance in particular, lie
south of I-80. There also continues to be a marginal severe
potential with enough instability in place to possibly generate
some sizable hail and strong winds.
Additional storm chances overnight will originate from eastern
Minnesota and drop into the CWA from the north, although there
remains a great deal uncertainty with this system. This evening, we
find a broken line of storms firing up near the Mississippi in far
eastern Minnesota and western Wisconsin along a couple of frontal
boundaries. A handful of high-res models suggest that this line,
currently propagating to the east, will dive southward overnight
following the axis of higher theta-e and subsequently greater
instability. Aside from a modest jet max, forcing is none too
impressive as the line drops through Wisconsin. For that reason, a
number of models have the line dying out prior to reaching the IL/WI
state line. However, if the line can generate ample cold pools on
its leading edge, then the added forcing for ascent will give it a
fighting chance at making it into the CWA. Guidance appears to be
shying away from this idea though. That leaves the northern and
central CWA with lesser rain chances tonight than areas further
south.
Doom
&&
.SHORT TERM...
Issued at 340 PM CDT Wed Jun 28 2023
Through Thursday night...
Forecast concerns in the short term...
*Lingering smoke and poor air quality through tonight and into
the day on Thursday
*Thunderstorms expected to develop tonight into Thursday
morning with another round of storms possible Thursday
afternoon/evening
*Any thunderstorms that develop will contain a potential to become
severe with damaging winds and hail as the primary threats
Our area continues to reside along the northern periphery of an
upper-level ridge that is parked across the southern CONUS. Under
this ridge wildfire smoke from Canada continues to cause reduced
visibilities and poor air quality across the entire area. HRRR/RAP
smoke guidance continues to hint that smoke concentration should
gradually ease through the night, but so far has not been
preforming as expected. Therefore, I would not be surprised if
smoke lingers into the day on Thursday though a lot of the smoke
coverage may depend on where storms develop overnight. So for now
I have maintained a mention of smoke through tonight but did not
add more for tomorrow due to aforementioned uncertainty.
Subtle shortwave impulses continue to traverse across the
northern Plains and Mississippi River Valley this afternoon which
has developed some shower and thunderstorms across Minnesota,
Iowa, and central Illinois. While these storms in particular are
expected to remain away from our forecast area, additional
thunderstorms are expected to develop near us tonight as the
shortwave moving through South Dakota intersects the warm
advection associated with a warm front lifting through Missouri.
Forecast soundings do show steep mid- level lapse rates around 8
C/km and MUCAPE values in excess of 1000 J/kg which should support
elevated thunderstorms developing as these features come
together. However, guidance continues to be all over the place as
to where storms will develop and how widespread they will become.
The best estimate based on when the aforementioned ingredients
come together is that storms should begin to develop across
portions of northern and central Illinois around midnight tonight
and linger into Thursday morning before moving into Indiana.
Furthermore, bulk shear values around 40 kts would also support
upscale growth of any storms which could contain a threat for
large hail and possibly damaging winds if downdrafts can punch
through the stable boundary layer.
As the anticipated overnight storms exit the area, the
combination of diurnal heating and continued moist advection
should allow the atmosphere over us to destabilize. Forecast
soundings indicate that MLCAPE values upwards of 2500 J/kg would
be able to develop in addition to the lingering steep lapse rates
aloft. These conditions should be sufficient to allow additional
thunderstorms to develop Thursday afternoon and evening along
residual outflow from tonight`s convection. However, exact timing
and placement of storms continues to be uncertain and will largely
depend on the coverage and quick exit of tonight`s storms.
Regardless, lingering wind shear values around 40 kts will support
a severe potential with any storms that do develop Thursday
afternoon. The primary threats from any storms should be in the
form of large hail and damaging winds, but an isolated tornado is
also possible especially with any supercell structures early on.
Though low-level winds fields do look to be a bit meager which
could limit the already small tornado threat.
Given the large amount of uncertainty in regards to all of the
thunderstorm activity I have maintained 30 to 50 percent POPs
across the area for this potential through Thursday night.
However, I do anticipate at least a couple of dry hours on
Thursday in between the morning and afternoon convection.
Additionally, temperatures Thursday afternoon are forecast to warm
into the upper 80s and lower 90s which in combination with the
mid to upper 60s dew points will make temperatures feel near 100
degrees in spots. Though there is a chance temperatures could
verify cooler if the morning storms linger longer. Try to keep
updated with the forecast through the day on Thursday as this
thinking may change as storms take shape.
Yack
&&
.LONG TERM...
Issued at 315 PM CDT Wed Jun 28 2023
Friday through Wednesday...
Key Forecast Messages:
* Periodic shower and thunderstorm chances through Independence
Day, highest Saturday-Sunday though with plenty of uncertainty
* Very warm and humid Friday, lower temps over the weekend,
coolest Sunday, then warming back up, especially Independence
Day and next Wednesday
Barring effects from Thursday night convection spilling over into
early Friday morning, the convective signal for the rest of
Friday is rather muted. This is due to lower instability as steep
lapse rate plume departs, potential for capping issues, and
modest/nebulous at best forcing mechanisms. As a result, kept PoPs
in the slight to low chance range, and it`s plausible a sizable
chunk of the CWA ends up dry for the daytime hours. If convective
coverage does end up low during peak heating, low-level thermal
progs featuring forecast 850 mb temps in the upper teens and 925
mb temps in the low-mid 20s Celsius support highs in the upper 80s
to around 90 away from the lake cooling footprint.
As is typical in these low amplitude/nebulous regimes on the
northern fringe of a heat dome ("ring of fire"), the guidance is
very mixed Friday night. Showing an uptick in PoPs, implying a
bit more of a signal in the NBM members, though confidence is on
the lower side. If the instability gradient is shunted south, as
is shown on some of the operational guidance, that would favor our
southern CWA and points south.
Heading into Saturday, the typical variance in handling (likely
convectively modulated) short-waves plays a role, plus once again
regarding where the baroclinic zone and instability gradient set
up. With the big picture idea of higher instability favored over
southern areas, think that Saturday generally points toward
locations near and south of I-80 having a relatively higher chance
of showers and storms. There`s a plausible scenario in which the
northern half of the CWA ends up primarily dry into or through
Saturday evening. Higher end PWATs poking northward suggest that
where thunderstorms develop Saturday-Saturday night would have a
threat for heavy/torrential downpours, while weak mid-level lapse
rates and marginal bulk shear point toward a marginal at best
threat for organized convection.
There`s better agreement in a short-wave trough translating east-
northeastward on Sunday, with cloudy, cooler, and showery
conditions area-wide. However, higher PoPs and relatively higher
but still low thunder chances are currently indicated south half
or so of the CWA due to limited instability focusing southward.
Some of the forecast guidance temporarily closes off and slows
Sunday`s trough, which would keep the cooler and showery
conditions around even into Monday.
The above being said, the NBM forecast currently leans in favor
of the trough exiting east by Monday, enabling seasonably warm
conditions to more quickly return, and then Tuesday (Independence
Day) and Wednesday featuring very warm conditions away from the
lake and moderate humidity levels. With higher heights yielding a
lack of appreciable large scale forcing, subtle convergence and
reaching convective temp could drive some isolated to widely
scattered convection centered on peak heating Monday through
Wednesday, implying widespread disruption of outdoor events to be
less likely at this vantage point. Stay tuned.
Castro
&&
.AVIATION...
For the 00Z TAFs...
Aviation weather concerns consist of:
* Continued IFR/low-MVFR vsbys due to smoke. Low confidence on
improvement to MVFR and VFR.
* Increasing chances for showers and thunderstorms overnight and
Thursday morning.
* Southwesterly winds developing through Thursday morning and
afternoon.
* Another potential round of thunderstorms Thursday afternoon or
evening.
Smoke with generally IFR vsbys continues to impact most of the
terminals this evening and based on recent satellite loops,
expecting little change in vsbys tonight.
In coordination with the ZAU CWSU, converted the PROB30s to TEMPO
groups for TSRA late tonight. While uncertainties remain regarding
precise placement/timing of convection, the signal for
thunderstorms continues to increase, with confidence sufficient to
justify TEMPO mentions at this time.
Surface winds will gradually trend out of the southwest through
tomorrow morning. As this occurs, the densest smoke may finally
begin to lift north of the region, but suspect that MVFR vsbys in
HZ/FU may very well persist. Finally, while the TAFs reflect a
"dry" forecast tomorrow afternoon and evening, the potential for
another round of thunderstorms exists. Confidence in favoring a
particular 4-6 hour window remains too low to warrant a PROB30
introduction right now, with it also possible the bulk of activity
remains south and west of c90.
Carlaw
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1053 PM CDT Wed Jun 28 2023
.UPDATE...
Issued at 946 PM CDT Wed Jun 28 2023
It continues to be a rather challenging forecast with convective
potential rounding the upper trough late tonight into Thursday.
Latest changes were made to clear PoPs from the forecast through
06z this evening and that may not even be aggressive enough.
The primary focus is over the NE/CO/KS region, where two
shortwaves come into play. The two seem to conjoin later this
evening before ejecting east-northeast along the MO/IA border
late tonight into Thursday morning. Hi-res guidance continues to
delay the onset of convection, which makes sense given the late
arrival of the shortwave. HRRR has been most consistent in the
convective initiation being along and just north of the MO/IA
border in the vicinity of the warm front. From there, the main
question has been the southern extent of the activity as it round
the northern edge of the upper ridge, in addition how soon it
dives southeast. This is where most CAMs seem to have some
consensus in keeping action largely east of the Mississippi River
with the latest HRRR making and ever-so-slight eastward nudge.
All that being said, the later arrival and progression of the
convection will most certainly play into convective potential
Thursday afternoon with the potential for remnant cloud cover
to curb further destabilization. We will need to continue to
analyze further changes given what pans out later tonight into
Thursday morning.
Maples
&&
.SHORT TERM... (Through Late Thursday Night)
Issued at 247 PM CDT Wed Jun 28 2023
Short Term (Today through Thursday Night)
Scattered showers along with a few rumbles of thunder are making its
way east across the CWA and will be out of the area by late
afternoon. Cloud cover will decrease as the precipitation moves
eastward. With the increased cloud cover and light precipitation,
temperatures are not heating as quickly as previously anticipated.
Regardless, as cloud cover diminishes temperatures will quickly heat
up with hot and humid conditions through the afternoon.
A warm front associated with a surface low pressure system in Kansas
is currently located over southwest MO. Through the evening into
early tomorrow morning, the warm front will trek northeastward and
extend across northern MO and southeastward along the Mississippi
River. A surge of low level moisture will accompany the front,
providing a chance for showers and thunderstorms to move along and
east of the boundary where the best chances are in central IL. There
is a sharp surface based CAPE gradient further to the west, closer
to the Mississippi River. We will be keeping an eye on whether or
not initiation occurs in Iowa where the greatest convergence will
be. If initiation does occur, an MCS may tend to trek along the
surface based CAPE gradient like the Corfidi vectors suggest.
Temperatures on Thursday are still forecast to be the hottest of the
year thus far with highs in the upper 90s and low 100s. There
remains uncertainty how hot temperatures will be as current guidance
has a high temperature spread of up to 8 degrees in some locations.
The uncertainty comes from how much mixing occurs. Higher mixing
will dry out the air causing temperatures to be hotter and not as
humid. Less mixing will help keep dew points higher thus keeping
temperatures on the lower end of the spread but more humid.
With southwest winds and downsloping off the Ozarks, confidence is
increasing that central MO will see a drier heat as dew points will
be the lowest. Dew points in west central and southwest IL will be
the highest but will be dependent on if the MCS does trek that far
south. If this is the case, locations in central and southwest IL
will see temperatures primarily in the mid to upper 90s with high
dewpoints leaving hot and humid conditions. An heat advisory is
in effect for Thursday starting at 15Z and because of the
downsloping effects, the heat advisory has been expanded north
just slightly in east central MO.
The low pressure system will move across the area by late Thursday
night and have an associated front will stall across northern MO.
This will potentially provide another chance for scattered showers
and thunderstorms in the far eastern portions of the CWA.
MMG/Gosselin
.LONG TERM... (Friday through Next Wednesday)
Issued at 247 PM CDT Wed Jun 28 2023
(Friday - Sunday)
Ongoing elevated convection is likely to be ongoing Friday morning.
Of course, the question is where and will depend on initiation time
and location. Best guess is somewhere across the mid-Missouri Valley
Thursday night based on where stronger low-level moisture
convergence likely will reside coincident with a midlevel shortwave
trough rounding the crest of the ridge axis. Given the stronger
synoptic component (i.e., pronounced shortwave trough), the MCS
(assuming one does indeed form) likely will be forward
propagating. These Corfidi vectors late Thursday night into early
Friday are generally westerly, so the southern portion of the
storms may clip far northern sections of the CWA. There is some
uncertainty however on where storms form and the exact track of
the aforementioned shortwave trough. It is possible that
everything is pushed a bit further south than currently forecast,
which would yield higher rain chances (and expansion southward) in
parts of the CWA. Damaging winds would be the main threat with
any storms that do impact the region.
A minimum in thunderstorm chances should exist in the late morning
and early afternoon hours after the morning thunderstorms/MCS
departs the mid-Mississippi Valley. Unlike Thursday afternoon
though, a weaker cap will be in place across the area so we may be
more prone to convective initiation of surface-based thunderstorms
during the late afternoon and early evening hours. The environment
should be quite supportive of severe weather, with enough shear (25-
35 knots) on the northern edge of the midlevel ridge and instability
(>2000 J/kg of CAPE). Supercells and multicell clusters/line
segments would likely be the convective mode with large hail favored
in any supercells and damaging winds in any clusters/line segments.
The threat is definitely conditional however, with a lack of any
clear mid/upper level forcing mechanisms to help initiate storms
near the stalled frontal boundary. Outflow boundaries from
antecedent convection could also play a role and help initiate
activity but there is no predictability pinpointing those this far
out in time.
There is a bit more uncertainty with respect to temperatures (and
heat index values) on Friday, given the slightly better chance for
afternoon showers and thunderstorms. In addition, exactly where the
west-east oriented surface boundary will be key, with about a 50-100
mile difference between deterministic guidance. Warmest temperatures
are likely to be near and just south of the front and further to the
west where deeper mixing is anticipated. Our central and
southeastern Missouri counties are most likely to be far enough
south to experience another very hot day with high temperatures in
the 100-105 range and peak heat index values over 105F. Parts of
central Missouri though are a bit more vulnerable to a slight shift
to the south of the frontal boundary compared to southeast Missouri,
so there is more uncertainty for instance in Jefferson City and
Columbia`s high temperatures compared to Farmington. The latest NBM
supports this idea, with spreads between the 25th/75th percentile
nearing 10 degrees at KJEF/KCOU compared to around 5 degrees at
KFAM.
The slow and gradual breakdown of the mid/upper level ridge
continues Friday night into the weekend. The expectation is for the
development of nocturnal thunderstorms (possibly an MCS) Friday
night as the low-level jet intensifies with another midlevel
shortwave trough moving overhead. This activity is likely to be
further south than the subsequent rounds, with likely PoPs in
northeast Missouri and west-central Illinois and chance PoPs into
central and eastern Missouri as well as south-central Illinois. The
pattern is very slow to change through Sunday, with a stalled
frontal boundary oozing equatorward with time and a closed midlevel
low developing to our north. Convection looks to transition more of
an unorganized, scattered nature and likely more diurnally-driven as
well. In terms of the drought, the good news is there likely will be
at least scattered convection both Saturday and Sunday, but the bad
news is the pattern this weekend does not look as favorable for
widespread beneficial rainfall. Earlier rounds preceding this
however may be just that and clip northern sections of the forecast
area. Individual showers and storms may be efficient however, with
precipitable water values around 1.75" (> 90th percentile on the
NAEFS) and deep warm cloud depths (~12 kft AGL). Chances of strong
to severe storms look lower this weekend (particularly Sunday) given
weak midlevel lapse rates, lessening instability, and more modest
deep-layer shear (closer to 25 knots).
Temperatures will be on the downturn starting Saturday, though we
will have to watch Saturday afternoon in parts of southeast Missouri
and southwest Illinois south of the boundary. Heat index values of
100-105+ are possible in these locations Saturday afternoon, but
will need any convection and debris clouds to stay to the north. For
most locations, upper 80s to mid 90s are forecast. By Sunday, near
normal values are favored areawide.
(Sunday Night - Next Wednesday)
Weak quasi-zonal or northwest flow is favored aloft early next
weekend. The latest WPC 500-hPa height clusters show very little
variance in the pattern, increasing confidence in sensible weather.
That being slightly above normal temperatures and likely dry weather
through the 4th of July with subsidence aloft behind the departing
Great Lakes trough. Cannot rule out some diurnally-driven activity,
but chances at this time are on the low side and below
climatological normals (~35%).
Both the GEFS/EPS suggest the next midlevel shortwave trough will
eject out of the Rockies Tuesday night into Wednesday. This feature
should bring an increasing chance of showers and thunderstorms by
Wednesday.
Gosselin
&&
.AVIATION... (For the 06z TAFs through 06z Thursday Night)
Issued at 1044 PM CDT Wed Jun 28 2023
Central MO terminals remain VFR throughout the TAF period. While
metro terminals are favored to remain VFR, there is still some
uncertainty in the evolution of a convective complex that will
materialize in the vicinity of the MO/IA border and track
southeast Thursday morning. Latest trends have nudged it even
slightly further east, which would place KSTL/KCPS on the western
most fringe of thunderstorm potential Thursday morning. Provided
the uncertainty, prevailing VCSH/VCTS was withheld from the
latest update.
KUIN stands the best chance (30-40 percent) to experience
thunderstorms, but remains just south of the corridor of the main
track of the broader field of development. KUIN will need to be
closely monitored as convective activity plays out through pre-
dawn hours with any adjustments coming in later updates. If there
is enough southward extent to convection, a direct impact could
result in gusty winds, locally heavy rain and the potential for
hail with the strongest cells.
Aside from thunderstorm potential, winds will be rather chaotic
with waffling frontal boundary near the MO/IA border and/or
outflow resulting from thunderstorms.
Maples
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory from 10 AM Thursday to 7 PM CDT Friday for Audrain
MO-Boone MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-
Gasconade MO-Iron MO-Jefferson MO-Lincoln MO-Madison MO-
Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls
MO-Reynolds MO-Saint Charles MO-Saint Francois MO-Saint
Louis City MO-Saint Louis MO-Sainte Genevieve MO-Warren MO-
Washington MO.
IL...Heat Advisory from 10 AM Thursday to 7 PM CDT Friday for Bond IL-
Calhoun IL-Clinton IL-Jersey IL-Madison IL-Marion IL-Monroe
IL-Randolph IL-Saint Clair IL-Washington IL.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
929 PM EDT Wed Jun 28 2023
.SYNOPSIS...
Canadian wildfire smoke continues to filter through the region
as upper level troughing progresses eastward toward New England.
High pressure will briefly build at the surface Thursday into
Friday. Shower and thunderstorm chances return late Friday into
early next week as an area of low pressure over the Great Lakes
and it`s associated cold front approach the region.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Code Orange Air Quality along and east of Hagerstown, MD
continues tonight, with Code Red in effect to the west.
Visibility is reduced widely across the area, with much of the
region reporting 3-5SM visibilities. Some locations are already
seeing further reductions as more smoke streams down from Canada
tonight. With lighter winds overnight, this trend is expected to
continue, particularly during the 2AM-9AM time frame tonight as
suggested by the HRRR Smoke model. All zones within our area
that issue Air Quality Alerts have gone Code Red for the
forecast on Thursday as air quality worsens with increasing
smoke and light winds under high pressure.
Previous discussion follows...
The smoke will continue to funnel south and east from eastern
Canada through tonight with brief high pressure building in.
Highest concentrations of smoke will be west of the Blue Ridge
with more diffuse concentrations further east based on the
timing of and placement of the plume as it moves through. Hi-
res model guidance shows an additional push of smoke and poor
air quality Thursday morning into early Thursday afternoon.
Lows tonight will fall back into the low to mid 50s over the
mountains with values around 60 in the urban locations. Some
patchy fog is possible with mostly clear to partly cloudy skies.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Brief high pressure will build over the region Thursday with light
northwest winds switching to the west and southwest later in the
day. Air quality will remain poor especially during the morning
and early afternoon hours with general improvement as the winds
switch later in the day. Conditions will remain dry with mostly
sunny to partly cloudy skies with high pressure nearby. Once
again expect a milky appearance to the skies especially in areas
along and west of the Blue Ridge where the smoke will be a
little less diffuse. Winds will also be a bit lighter which
could limit the smoke as it pushes southeast, but also allow it
to settle closer to the surface.
The smoke/haze and air quality looks to improve late Thursday into
Friday as high pressure slides offshore. Meanwhile, a warm front
will begin to approach from the south and west with several pieces
of energy pushing through later this week and into the weekend
ahead. 12z CAM/deterministic guidance places our region on the
northeastern extent of the southeastern U.S ridge lining us square
with any convection that may form upstream over the Great Lakes/Ohio
River Valley. Current guidance suggest multiple convective
waves tracking south of the region late Thursday night into
Friday and again Friday into Saturday. Uncertainty remains in
the evolution of these disturbances upstream due to the
placement of the mean upper trough in the northern stream and
strength of surface high/upper level ridge south. 12z CAM
guidance alludes to slightly higher mid- level heights which
could suppress convection for a period of time heading into
Friday afternoon. For now, went with an uptick of shower and
thunderstorm activity Friday afternoon into Friday evening
compared to the introduction of PoPs Thursday night due to
placement of convection upstream. Warm/moist advection will
persists with CAPE values upwards of 1500-2500 j/kg and 0-6 km
vertical shear values of 15 to 25 kts. With that said,
convective coverage will remain scattered and weakly organized
mainly during the afternoon and evening hours. More disturbances
will continue to come around the "ring of fire" from the plains
and continue to ignite storms throughout the weekend ahead.
By Saturday, the warm front should cross the region. Moist/warm
advection will continue to increase along with instability
during the afternoon and evening hours. This will yield a
typical Summer-time regime of diurnally driven showers and
thunderstorms. The focus Saturday will be along the front as
well as across the high terrain and potentially the bay/tidal
Potomac due to the bay/river breeze. CAPE values will remain on
the order of 1000- 2000 j/kg with stagnant shear values below 25
kts.
High temperatures Thursday will be slightly warmer today with
winds shifting to the west and southwest late in the day. Expect
highs in the mid 80s for most outside the mountains/bay. Lows
Thursday night will fall back into the 50s and 60s with
increasing humidity. Highs Friday and Saturday will push into
the mid to upper 80s with lows in the 60s and 70s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Prolonged summer pattern will continue for most of the long term
period as upper ridging builds to the south and multiple surface to
upper-level troughs build to the north. Near the surface, a warm
front will likely lift northward Friday night into early Saturday.
Additionally, a cold front will cross into the Mid-Atlantic by late
Sunday into early Monday. Each pass will provide the best coverage
of showers and thunderstorms given a clear frontal forcing to go off
of. Temperatures will be persistent for the period, with upper 80s
to low 90s for highs for the lower elevations while in the 60s and
70s for most at night aside from the mountains where temperatures
may be 10 to 15 degrees cooler.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
Haze and smoke look to remain the primary issue to aviation
through the evening hours. Most terminals can expect MVFR vsbys
tonight, possibly dropping into high-end IFR as another thick
stream of smoke is anticipated to move into the region between
2AM-9AM overnight. MRB would see the reduced vsbys earliest, but
confidence on how much they`re reduced is lower, as being more
elevated than other terminals may limit the impact of the near-
surface smoke.
More smoke and potential vsby reductions are likely Thursday
as additional smoke funnels through. Once again TAF locations
could bounce between VFR to MVFR during the morning and
afternoon hours. Valley locations will also deal with patchy fog
Thursday morning due to weekend winds and clearing skies with
high pressure overhead. Winds will shift to more southwesterly
late in the day Thursday decreasing the smoke across the
terminals. Expect southerly winds to continue into Friday, while
becoming slightly gustier in nature. Convective chances also
return which may lead to some brief restrictions although most
of Friday should be VFR.
VFR conditions should persist for the weekend with occasional brief
restrictions in CIGs and Vsbys due to heavy shower or strong
thunderstorm activity over the terminals at times both Saturday
and Sunday afternoon and evening. Winds will be out of the south
on Saturday before turning more out of the southwest on Sunday.
&&
.MARINE...
Expect a shift to southerly flow by the second half of
Thursday, continuing into Friday. Some southerly channeling
effects are possible by early Friday evening, particularly
across the Chesapeake Bay, and continuing into the overnight.
Convective chances increase on Friday which may lead to periods
of hazardous conditions on the waterways.
Weak flow on Saturday will lead to sub-SCA conditions as well into
Sunday. Although, there may be Special Marine Warnings for both
afternoons and evenings with any thunderstorms that may cross the
waters.
&&
.TIDES/COASTAL FLOODING...
Tidal anomalies remain between a half foot and one foot, and are
expected to hold steady or fall slightly over the next couple days.
More sensitive sites like Annapolis, DC, and Straits Point may enter
low-end Action Stage over the next few tide cycles, but no flooding
is anticipated.
&&
.EQUIPMENT...
KLWX will be down for approximately ten days for an important
upgrade. Technicians will refurbish and replace the pedestal,
one of the most critical components of the radar, which is
necessary for antenna rotation and positioning to capture data
in all directions. The components are extremely heavy and will
require the radome to be removed by crane and replaced when the
work is completed. Estimated return to service is June 30th,
barring any unexpected issues.
During the downtime, adjacent radars will be available,
including: Wakefield, VA (KAKQ), Roanoke, VA (KFCX), Dover, DE
(KDOX), Charleston, WV (KRLX), Pittsburgh, PA (KPBZ), State
College, PA (KCCX), and Fort Dix, NJ (KDIX)...also FAA Terminal
Doppler radars for Dulles (TIAD), Reagan National (TDCA),
Thurgood Marshall BWI (TBWI), and Joint Base Andrews (TADW). For
direct access to any of these surrounding radar sites, visit
the following Web page: https:/radar.weather.gov/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.
&&
$$
SYNOPSIS...CAS/EST
NEAR TERM...CAS/EST
SHORT TERM...CAS/EST
LONG TERM...ADM
AVIATION...ADM/EST
MARINE...BRO/ADM/EST
TIDES/COASTAL FLOODING...CPB/KJP
EQUIPMENT...LWX
East Central Florida Forecast Discussion
National Weather Service Melbourne FL
917 PM EDT Wed Jun 28 2023
.DISCUSSION...
Current-Overnight...An area of lightning storms currently in the
diminishing phase over Osceola and southern Brevard counties will
slowly sink south, with an expectation that further lightning
strikes will come to an end over land by 11 PM to midnight. HRRR
suggests a few marine storms will remain in the forecast over the
buoyant largely near the gulf stream waters overnight. Expect lows
in the mid to upper 70s, with partly cloudy skies and light variable
winds.
prev disc...
Thursday-Friday...An upper level ridge across the Ark-La-Tex region
will gradually shift eastward toward the Florida peninsula Thursday
into Friday. A few shortwaves will move southward toward the
peninsula during this period, which combined with lingering moisture
associated with a weakening frontal boundary will provide a
favorable environment for some isolated to scattered shower and
thunderstorm development across east central Florida. Areas south of
the I-4 corridor have the best chances of seeing shower and
thunderstorm development, as a drier airmass is forecast to slowly
filter in across northern portions of the area. PoPs 30-50 percent
on Thursday will decrease slightly to 30-40 percent on Friday. The
east coast sea breeze is forecast to develop both afternoons, with
onshore flow assisting in its development and inland push.
Heat will continue to be a concern Thursday and Friday, with
afternoon highs reaching into the low to mid 90s across east central
Florida. Dewpoints remaining in the mid 70s will continue to make
heat indices climb above 100. Current guidance indicates that
Thursday will be the warmer of the two days, with peak heat indices
102-107. Friday, peak heat indices remain around 100-104. Based on
this, both days will remain below local Heat Advisory criteria.
However, this will continue to be monitored as newer guidance comes
in.
Saturday-Wednesday (previous)...The aforementioned upper ridging
continues a gradual weakening as it flattens/expands eastward this
weekend, merging with western Atlc ridging into early-mid next week.
Weak surface high pressure ridging will focus across the central FL
peninsula into early-mid next week. The surface pressure gradient
remains fairly weak across the region with S/SE flow each day -
reverting back to a light offshore component each night/morning.
Much deeper moisture is forecast to push back into the area
beginning this weekend, and especially into early next week. Have
kept afternoon-early evening PoP chances in the scattered category,
but with further model consistency and forecaster confidence - some
of these days (next week) could get bumped up into likely.
Hot temps/Heat Indices continue to be the main story with maxes in
the L-M90s over the coastal counties and M-U90s inland. This results
in afternoon peak Heat Indices between 105-110F, which would likely
prompt Heat Advisories if guidance holds with these readings. Mins
will continue to get a little more uncomfortable, only dropping into
the M-U70s, though locales which receive heavy rainfall could
briefly reach the L70s.
&&
.MARINE...
Through Tonight...Isolated to storms possible through the overnight
hours as a weakening trough pushes further south across the Florida
peninsula and the local Atlantic waters. Any storms that develop
across the waters may be capable of producing brief gusty winds, and
cloud-to-water lightning. Light variable winds less than 10 knots
veering to out of the west overnight around 5 knots. Seas 1 to 3
feet.
Thursday-Monday...Rain chances will remain confined primarily south
of the Cape across the local Atlantic waters as the weak frontal
boundary drifts southward and drier air filters in from the north.
This pattern will remain in place through Saturday, with a
resurgence of moisture across the peninsula forecast through the
weekend and into Monday. Isolated to scattered thunderstorms cannot
be ruled out each afternoon across the waters. Onshore flow at 5 to
10 knots will dominate through Friday night, with winds veering to
out of the south-southeast at 5 to 10 knots Saturday through Monday.
Seas remain consistent through the period between 2 to 3 feet.
&&
.AVIATION...
(00Z TAFS) Issued at 917 PM EDT Wed Jun 28 2023
VFR conditions all sites overnight. Dryer Thursday, with only VCSH
mention from KMLB southward at the cst for now. Onshore winds will
develop by early aftn, moving well inland by mid-late aftn.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 74 91 73 89 / 20 10 0 10
MCO 75 95 74 94 / 40 20 10 10
MLB 75 90 76 90 / 50 20 10 20
VRB 74 91 73 90 / 50 30 20 30
LEE 75 96 74 95 / 30 10 0 10
SFB 75 94 73 93 / 40 10 0 10
ORL 76 94 75 94 / 40 20 10 10
FPR 74 90 74 89 / 50 40 20 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
JP/MW
Area Forecast Discussion
National Weather Service Morristown TN
1009 PM EDT Wed Jun 28 2023
...New UPDATE...
.UPDATE...
Issued at 948 PM EDT Wed Jun 28 2023
A few observations are still showing reports of hazy conditions this
evening and would expect this trend to continue over the next
several hours. Only changes needed this evening were to hourly
temperatures/dewpoints through the next 3-6 hours based on trends.
&&
.SHORT TERM...
(This evening through Thursday)
Issued at 254 PM EDT Wed Jun 28 2023
Key Messages:
1. Dry through tonight, with increasing chances of showers and
storms Thursday. However, confidence in timing and coverage remain
low at this time.
2. Warming trend begins tomorrow. While we do not look to reach
advisory criteria, it is still a good time to practice heat
safety.
Discussion:
Fairly simple forecast for the remainder of this afternoon and
tonight. The area remains sandwiched between upper level ridging
building in from the west and troughing slowly lifting northeast.
High pressure currently dominates at the surface. Deep nwly flow
has allowed for smoke to intrude the area from Canadian wildfires
and brought about hazy skies. This will really be the main impact
through tonight as warmer temperatures and a lack of recent
precipitation should limit any overnight fog to river valleys.
Things become a bit more complex Thursday as models have varying
indications of a potential decaying MCS approaching the region.
During the early morning hours Thursday, a surface boundary will be
a point of focus for convective initiation around IL/IN. Given a
favorable nwly flow setup, HREF members trend the area of showers
and storms to the region by around mid-day, however, there are
notable difference in the coverage and exact location of these
showers and storms that result in low confidence. Nonetheless, with
a warm and moist airmass at the surface there will be some
instability present. NAMNest and HRRR soundings generally show
surface based and most unstable CAPEs around 1000-1500J/kg, though,
MLCAPE is lacking. As a result, a few strong or possible severe
storms cannot be ruled out given the presence of any storms. The
main threat would be damaging wind, but again, the confidence is
low.
Lastly, we will be seeing the warming trend begin Thursday
afternoon. While we do not look to be meeting any advisory criteria,
portions of the southern valley could see heat indices approach
100F. Coverage of storms and associated clouds will have some
impact on this. Remember to practice heat safety such as drinking
plenty of water and taking breaks in shaded areas if you must
spend time outside.
&&
.LONG TERM...
(Thursday night through next Wednesday)
Issued at 254 PM EDT Wed Jun 28 2023
Key Messages:
1. Multiple rounds of showers/storms possible through the end of
the week.
2. Heat indices of 100 to 105 expected in the southern and central
TN Valley Friday and Saturday.
Discussion:
A large high pressure ridge will continue to maintain its grip
across the Southeast through the weekend. Over the next couple days,
the center of the ridge will slowly drift east, from eastern TX to
MS. This will place our area in a NW flow through the mid and upper
levels, steering convective complexes that develop over the Great
Lakes and Ohio Valley toward the southern Appalachians. The models,
particularly the NAM, bring multiple rounds of MCS remnants from
that region into our area from Thursday night through Saturday.
These MCS remnants will encounter a very warm/humid air mass as they
track toward the area, so some strong to severe storms will be
possible. The northern sections will be favored for the highest rain
chances, where there will be minimal to no capping, while southern
sections may remain capped without a forcing mechanism to break
through it. How convection evolves along outflow boundaries is
highly uncertain at this time.
Another uncertainty through Saturday will be how the MCS remnants
affect temperatures, either through increased cloud cover or outflow
boundaries. Confidence is high that we will be seeing the warmest
temperatures of the year thusfar, but there is less confidence on
how high the heat index will rise. NBM dewpoints in the mid 70s
during the afternoon seems too high, and will be adjusted down a
bit. With temperatures reaching the 93-98 range both Friday and
Saturday in central and southern sections, and dewpoints in the
lower 70s, the heat index is expected to be in the range of 100-105,
perhaps over 105 in Chattanooga. Later shifts may need to evaluate
the need for a Heat Advisory, but for now, it is too early to issue
one given the marginal heat index values that are expected and the
uncertainties regarding the MCS effects. Northern sections are
expected to have more cloud cover and surface moisture from the MCS
activity, and will have highs in the mid 80s to lower 90s.
On Sunday the ridge begins to flatten and sag southward as a
shortwave trough moves into the Great Lakes region. This will bring
a cold front toward the area and allow for better deep moisture
advection from the Gulf of Mexico. The front may linger in the
region for several days as it becomes nearly parallel to the
midlevel flow. This will raise the chance of showers/thunderstorms
for the entire area early next week. The forecast will favor a
diurnal trend to the PoPs, staying a little under NBM PoPs in the
chance range through Wednesday.
&&
.AVIATION...
(00Z TAFS)
Issued at 652 PM EDT Wed Jun 28 2023
VFR flight conditions with mostly clear skies and light winds are
expected over the next 24 hours. Haze at TYS and TRI will persist
for a couple more hours with some slight restrictions. Otherwise,
clouds will increase on Thursday with light winds.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 69 94 73 98 / 0 20 10 20
Knoxville McGhee Tyson Airport, TN 66 90 72 93 / 0 20 30 30
Oak Ridge, TN 65 89 72 93 / 0 20 30 30
Tri Cities Airport, TN 61 87 67 88 / 0 20 40 50
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...KRS
AVIATION...17
Area Forecast Discussion
National Weather Service Omaha/Valley NE
1005 PM CDT Wed Jun 28 2023
.UPDATE...
Issued at 1005 PM CDT Wed Jun 28 2023
00Z short term guidance has come into decent agreement of the
ongoing storms in northeast CO becoming a strong to severe
cluster/line of storms and rolling through southern portions of
the forecast area early Thursday morning. Damaging winds and
locally heavy rain/flooding would be the main threats. While it`s
always tricky to determine whether the strongest winds reach the
surface in an early morning system, forecast soundings reveal
little to no DCIN with plenty of instability (2500 to 3500 J/kg of
MUCAPE). In addition, there looks to be plenty of shear for storm
organization, with latest RAP suggesting around 35 kts in the 0-3
km layer and around 45 kts in the 0-6 km layer. Of course, with an
inversion set up, the values "available" to the storm will be
slightly lower, but still look to be sufficient for organized
storms. Unfortunately, confidence remains rather low in exact
timing, with CAMs ranging from 3 AM to 7 AM arrival time into our
western-most counties. Something to definitely keep an eye on over
the next several hours.
&&
.DISCUSSION...
Issued at 303 PM CDT Wed Jun 28 2023
Key Messages:
- An isolated severe storm is possible late this afternoon/early
evening with a few strong storms possible overnight.
- Shower and thunderstorm chances continue into the weekend.
Late this afternoon and tonight:
Early afternoon surface analysis indicates a weak front from
northwest IA to south-central NE with a pre-frontal trough
situated east of a Fremont-Lincoln-Beatrice line. The air mass
east of the surface trough is hot and moist with a deepening
cumulus field noted in visible satellite. While mesoanalysis
indicates considerable convective inhibition present across the
destabilizing warm sector, there is some suggestion (namely the
12z run of the NSSL-WRF and 18z NAMnest) the cap may weaken
sufficiently to support isolated storm development later this
afternoon over southwest IA. Should storm initiation occur, HRRR
forecast soundings indicate an overlap of strong instability and
seasonably strong deep-layer shear, which would support a
supercell storm mode with the primary hazard being large hail.
Tonight, the CAMs indicate the potential for elevated showers and
storms moving into the area from the west; though the timing and
placement of the convection is highly variable across the models.
Severe weather potential with that activity appears to be
relatively low with the strongest storms capable of small hail and
gusty winds.
Thursday through Saturday:
A midlevel trough currently over the Interior West will progress
east and reach the central Plains Saturday. In the low levels, the
boundary moving south through our area today is expected to stall
across KS with warm advection to the north of the front being the
primary mechanism driving precipitation chances into the weekend.
It appears that our best shot at measurable rain will be Thursday
night into Friday morning and Friday night into Saturday morning.
The potential will exist for isolated strong to severe storms
during those nocturnal convective episodes with the main hazards
being hail and locally heavy rainfall.
In regard to temperatures, tomorrow will be similar to today with
readings in the upper 80s to mid 90s. Maximum heat indices of
around 100 are forecast along the KS border. More cloud cover is
expected Friday and Saturday with highs in the 80s.
Sunday through Tuesday:
Building midlevel heights will translate to warmer daytime
temperatures with highs returning to the 90s early next week.
Measurable precipitation chances appear low during this time
frame.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 638 PM CDT Wed Jun 28 2023
Main forecast concern remains thunderstorm chances late tonight
into early Thursday morning. Unfortunately, there remains quite a
bit of spread in short term guidance regarding timing, location,
and coverage of storms. If storms do develop, the favored scenario
would suggest timing in the 6 to 10Z range, and most likely near
and/or just south of KOMA and KLNK. However, it`s just as likely
that little storm development occurs and no impacts are seen at
any TAF sites, so kept a dry forecast going for now. Otherwise,
outside of storms, expect VFR conditions to prevail with passing
mid clouds and light northerly winds becoming more northeasterly
into Thursday.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
UPDATE...CA
DISCUSSION...Mead
AVIATION...CA
Area Forecast Discussion
National Weather Service Spokane WA
348 PM PDT Wed Jun 28 2023
.SYNOPSIS...
Thunderstorms will bring locally heavy rain and gusty winds to
mainly the mountainous terrain of north Idaho and northeast
Washington today. Drier weather and hotter temperatures will
arrive Thursday as high pressure builds over the Western United
States. Afternoon temperatures in upper 80s to mid 90s are
expected across the Inland Northwest Thursday through much of
next week.
&&
.DISCUSSION...
Now through Friday: Storms continue to fire up over the Idaho
Panhandle and the higher terrains of Washington. Today looks to be
similar to yesterday but with less storm coverage over Eastern
Washington. There is currently a 500mb ridge developing off the
coast of Washington and moving inland towards our area whose
effects will begin to be felt more over the coming days. Today in
Douglas, Chelan, and Grant counties, the trough axis is bringing
subsidence to the desert valleys and limiting thunderstorm
potential due to the suppression of any lift that solar heating
could provide. The ridge is being slowed by an upper- low that is
currently weakening over the desert southwest that’s beginning to
shear out and will dissipate over the next few days as the ridge
becomes broader and moves over the CONUS. In our area, the Idaho
Panhandle is the furthest from the ridge and is feeling its
effects the least so thunderstorm activity is still possible as
the easterly flow is pushed up the higher terrain. The HRRR and
GFS both agree that the Panhandle will have strong daytime heating
providing CAPE values near 1000 J/kg which is responsible for the
ongoing storms. The environment still has low shear in the order
of 10-15 knots, so most storms will still be quickly forming and
quickly dying. Some storms will be capable of producing heavy
rainfall as the Idaho Panhandle has near 1 inch PWAT values,
150-160% of normal. Steering flow is near 10 knots so storms won’t
pose a large flooding threat except over vulnerable burn scars.
Some severe hail will be possible with the strongest storms given
the large cape and a low LCL near 19 kilometers. Rainfall rates
near .5 inches/hour are possible. GFS simulated soundings show an
inverted-V over much of the area so gusty winds are a possibility
as well with stronger or dying storms. Storm activity will
increase in coverage over the higher terrain and the Idaho
Panhandle this afternoon before waning in the evening.
The ridge will continue to move inland tomorrow and Friday which
will bring high temperatures and low relative humidities. Thursday
will have another, albeit smaller, chance for thunderstorms in
the higher terrain as they are still outside of the ridge’s
strongest influences. The NBM has RH values between 15-25% Friday
so finer fuels like grasses will have no issue drying out.
/sinowitz
Saturday through Tuesday: Dry heat will be the overarching theme this
weekend into early next week. A push of dry air Friday night into
Saturday will bring precipitable water down to 60 to 80% of
normal while a ridge of high pressure will remain in place over
the Inland Northwest, keeping our temperatures well above normal.
Daytime highs will hold steady in the upper 80s to mid 90s
regionwide.
Saturday will have wind added to the mix as a result of a strong
pressure gradient across the Cascades. Winds will funnel through
the Cascade Gaps from west to east, bringing particularly windy
conditions to the Waterville Plateau and into the Western Colubmia
Basin including the cities of Wenatchee, Vantage, and Chelan.
Gusts up to 40 mph are expected.
Breezy daytime conditions will continue Sunday and Monday, though
winds won`t be quite as strong as on Saturday. The combination of
wind and dry heat will bring about fire weather concerns,
especially with the Fourth of July rapidly approaching. Brush
fires will start easily and spread quickly. /Fewkes
&&
.AVIATION...
00Z TAFs: Thunderstorms have migrated clsoer to Pullman,
Lewiston, and Coeur d`Alene. Probabilities of thunderstorms at
the aforementioned TAF sites is around 10-30 percent so VCSH and
TEMPO groups are utilized through 02z. Thunderstorms will decay
quickly with the setting sun this evening leaving VFR conditions
and light winds. /Butler
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 59 89 60 90 59 91 / 10 0 0 0 0 0
Coeur d`Alene 57 88 59 89 58 89 / 10 10 0 0 0 0
Pullman 55 86 56 88 56 89 / 10 0 0 0 0 0
Lewiston 63 94 66 97 66 97 / 10 0 0 0 0 0
Colville 52 89 52 89 50 91 / 10 10 0 0 0 0
Sandpoint 56 87 57 88 55 87 / 20 10 0 0 0 0
Kellogg 60 83 62 84 61 85 / 20 10 0 0 0 0
Moses Lake 60 93 58 93 57 96 / 0 0 0 0 0 0
Wenatchee 65 92 64 92 63 91 / 10 0 0 0 0 0
Omak 60 92 60 92 58 94 / 10 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Fire Weather Watch from Saturday morning through Saturday
evening for Foothills of Central Washington Cascades (Zone
705)-Okanogan Valley (Zone 703)-Waterville Plateau (Zone
706)-Western Columbia Basin (Zone 707).
&&
$$
Area Forecast Discussion
National Weather Service Paducah KY
608 PM CDT Wed Jun 28 2023
.UPDATE...
Issued at 608 PM CDT Wed Jun 28 2023
The AVIATION section has been updated for the 00Z TAF issuance.
&&
.SHORT TERM...(Tonight through Friday night)
Issued at 250 PM CDT Wed Jun 28 2023
A period of hazardous heat and humidity is the main weather story
for Thursday into Friday. A strong 500 mb high over the lower
Mississippi Valley region will expand northward over the next 48
hours. The accompanying 850 mb temperatures are very impressive,
with both the nam and gfs showing values in the upper 20s over se
Missouri. The dew point guidance has narrowed somewhat, and the
model consensus of lower to mid 70s will be used for the
forecast.
The potential for convection to interfere with the heat wave is
significant, mainly in southwest Indiana, the Pennyrile region of
west Kentucky, and se Illinois. The mid-level flow will remain
quite strong for such a hot ridge, with 500 mb winds of 30 to 50
knots. This raises the chances of a 500 mb impulse inducing a
thunderstorm complex. There is a decent signal among the cams that
a 500 mb impulse over the Wabash Valley late tonight will be
accompanied by a mesoscale convective complex. The hrrr suggests
this complex would track southeast from the Wabash Valley down
into the Pennyrile region Thursday morning. Lower and mid-level
wind fields will be strong enough to support the potential for
organized clusters, with isolated strong winds and hail.
In the afternoon, strong solar heating will destabilize the
atmosphere, with capes well over 3000. However, the very warm
temps in the 700 to 850 mb layer will produce very strong
convective inhibition, especially over se Missouri. Most of the
cams are lackluster regarding afternoon storms. Therefore, it
appears heat indices should eclipse warning criteria west of the
potential morning storms. An Excessive Heat Warning will be posted
for se Missouri, sw Illinois, and far west Kentucky. The Heat
Advisory will remain in place further east.
Another potential thunderstorm complex could move southeast toward
the forecast area Thursday evening. Most of the cams and lower res
guidance indicate any such complex would struggle as it moves into
strong convective inhibition / mid-level thermal ridging over our
area. It will be a rather warm night, with lows in the mid 70s.
On Friday, the synoptic setup will be basically unchanged. A
convective system could round the top of the ridge, affecting
primarily areas north and east of Paducah. Otherwise, potentially
dangerous heat and humidity will remain in place.
.LONG TERM...(Saturday through Wednesday)
Issued at 250 PM CDT Wed Jun 28 2023
A 500 mb shortwave will move east from the Plains, eroding the
capping inversion and producing a more favorable setup for
thunderstorms. The models have trended slower with this system.
The strongest upper-level forcing now appears more likely to occur
later in the holiday weekend, from Saturday night into Sunday.
The associated surface front will weaken as it approaches, and the
forecast wind shift to northwest is no longer evident in the
latest nbm. Therefore, a hot and humid pattern should continue
through the middle of next week. Thunderstorm chances will slowly
diminish Sunday night through early next week as the upper-level
flow flattens and gradually weakens. Heat indices are forecast to
remain below thresholds for headlines at this time, with the
possible exception of Saturday if organized convection holds off
until nightfall.
&&
.AVIATION...
Issued at 608 PM CDT Wed Jun 28 2023
MVFR visibilities in haze and smoke will continue at KEVV and KOWB
through the night or until SHRA/TSRA arrive. The latest guidance
brings TSRA into KEVV around 12Z and KOWB an hour or two later.
Used VCTS for a 3 hour period at both sites, but the convection
could get strung out through the entire morning. South southwest
winds will increase over the entire region in the afternoon.
Sustained winds at 12-14kts and gusts to around 20kts can be
expected.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory from 11 AM Thursday to 8 PM CDT Friday for
ILZ075>078-080>083-086-087-090-091.
Excessive Heat Warning from 11 AM Thursday to 8 PM CDT Friday
for ILZ084-085-088-089-092>094.
MO...Excessive Heat Warning from 11 AM Thursday to 8 PM CDT Friday
for MOZ076-086-087-100-107>112-114.
IN...Heat Advisory from 11 AM CDT /noon EDT/ Thursday to 8 PM CDT /9
PM EDT/ Friday for INZ081-082-085>088.
KY...Heat Advisory from 11 AM Thursday to 8 PM CDT Friday for KYZ007-
010>022.
Excessive Heat Warning from 11 AM Thursday to 8 PM CDT Friday
for KYZ001>006-008-009.
&&
$$
UPDATE...DRS
SHORT TERM...MY
LONG TERM...MY
AVIATION...DRS
Area Forecast Discussion
National Weather Service Pittsburgh PA
937 PM EDT Wed Jun 28 2023
.SYNOPSIS...
Dry weather with moderating temperature is expected through
Thursday under the influence of high pressure. Periods of haze
resultant of Canadian wildfires may impact air quality through
Thursday. Thunderstorm chances will increase with a series of
shortwaves heading into the weekend.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Latest observational trends have been showing visibility
decreasing over the past couple hours as the nocturnal inversion
sets up, and with that do not expect improvement overnight in
regards to the Canadian wildfire smoke that has moved in to the
region. Hi- res models suggest that there should be minor
improvements by late morning, but overall, expect another hazy,
smokey day.
The Air Quality Alert for CODE RED (Unhealthy) conditions for
particulates - 2.5 um. has been extended for Pennsylvania through
Thursday, expiring tomorrow at midnight.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Surface high pressure is expected to shift east of the Upper
Ohio River Valley Thursday in response to a weak shortwave
missing toward the Western Great Lakes. Combined with height
rises, expect temperature to return to seasonable values for
Thursday with no chance for precipitation. The main focus
Thursday will be on potential air quality improvements, but
initial hi-res model runs suggest some haze/smoke could linger
though concentrations may not be as dense. Please consult with
local DEP agencies and other resources like airnow.gov for the
latest air quality information.
Starting Thursday night into Friday night, the upper Ohio River
Valley will be positioned approximately at the eastern edge of
convergence between a Quebec trough and southern MS River Valley
ridge. Shortwave movement between these two features is likely
to foster thunderstorm development in various forms, traversing
from the western Great Lakes toward the eastern Tennessee River
Valley and portions of the Upper Ohio River Valley.
For this forecast area, the evolution of these convective
systems will greatly dictate the expected weather through Friday
night. Uncertainty in the timing, location and evolution of
convection means great variance between potential dry weather
and slightly above normal temperature to potential rounds of
strong to potential severe storms with near normal temperature.
Ensembles favor a dry Thursday night period with increasing
chances heading into the Friday night period, with potential for
strong to severe storms Friday afternoon and evening. Rather
than note possible environmental variables to could create a
severe hazard, it remains best at this time to be aware of a
low-probability threat and monitor the latest forecasts as they
get a better grasp of upstream storm evolution.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Ensemble models favor the Upper Ohio River Valley becoming
situated between the northern trough and southern ridge as east
slide east through the weekend. This setup favors daily rounds
of showers and thunderstorms, seasonal temperature, and low-end
severe threats (again, depending on prior day setup).
A pattern shift becomes likely heading into the 4th of July
holiday as a trough of low pressure sweeps from the Central
Plains towards the eastern U.S. This will maintain shower and
thunderstorm chances but potentially diminish the severe threat,
while creating a clear dry period after it exits sometime around
mid next week.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
MVFR to IFR is expected to continue through Thursday morning as
smoke and haze from the Canadian wildfires restrict visibilities
across the region. Sfc obs indicate 3kft to 5kft cigs across much
of the area, through satellite indicates few clouds at those
levels. This is likely due to partial sfc obscuration, with
vertical visibility limited by the smoke and haze. Will include
these bkn cigs in the tafs, but not with a total obscuration and
VV cig.
Some fog is expected to develop overnight, which should result
in more widespread IFR vsbys. Mixing should dissipate the fog
Thursday morning, though HRRR and RAP smoke guidance indicate at
least MVFR vsbys continuing through the day as w-nw flow aloft
maintains the smoke and haze.
.OUTLOOK...
Smoke and haze restrictions should end Friday as wind aloft
shifts to the SW. A shortwave trough returns restriction and
shower/thunderstorm potential to the region later Friday and
Friday night. Ocnl shower and thunderstorm and restriction
potential remains through Monday with slow moving low pressure.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...Frazier
NEAR TERM...Frazier/88
SHORT TERM...Frazier
LONG TERM...Frazier
AVIATION...WM
Area Forecast Discussion
National Weather Service Tucson AZ
214 PM MST Wed Jun 28 2023
.SYNOPSIS...Temperatures will fall back a few degrees before
ramping back up to excessive heat levels over the weekend, with
afternoon highs 10 to 12 degrees above average. Meanwhile, a
modest moisture increase will bring a chance of thunderstorms
mainly east and southeast of Tucson today and Thursday. Breezy at
times.
&&
.DISCUSSION...High pressure continues to shift eastward into the
Gulf States as a weak trough digs into much of the intermountain
west. Temperatures have backed down from excessive heat levels
last weekend to just a few degrees above average through the rest
of the week.
We`ve been tracking a moisture increase from Sinaloa through
Sonora, and more broadly up the Gulf over the past 120 hours. As
expected, we saw a nice little moisture increase overnight with
the 12Z KTWC sounding coming in close to 1 inch precipitable
water, and surface dewpoints generally in the 50s to start the
day (up 10 to 20 degrees over the past 24 hours). We`ve managed to
hang onto surface dewpoints in the 40s this afternoon as
scattered thunderstorms extend from northern Sonora through most
of Cochise county. This won`t last (yet) but may be stubborn
enough to bring a few storms again Thursday afternoon with another
round of convective outflow showing up on the HRRR tonight.
As high pressure builds through the region across Nevada,
California and Arizona this weekend, most of the moisture will be
shunted back out of the area. Meanwhile, excessive heat again
becomes the main threat with afternoon highs climbing 10 to 12
degrees above average over the weekend and into early next week.
That includes another round of 110+ for Tucson Metro.
More signs of life and promise in the tropics. Hurricane Adrian
earned the first name of the season even as another area south of
Mexico shows favorable progress toward becoming the second
tropical cyclone of `23. The track of the second potential storm
could end up being very helpful toward setting a more solid
foundation through central Mexico as conditions are favorable for
a track farther north and closer to the west coast of Mexico. We
might not have a very busy July 4th, but later in the week could
start to introduce more storms across the border.
&&
.AVIATION...valid through 30/00Z
SCT-BKN clouds AOA 15k ft AGL through 29/09Z for KDUG. SKC
conditions for KTUS through the entire TAF period with occasional
FEW clouds AOA 15k ft AGL for KOLS through 29/04Z. Aft 29/20Z, FEW
clouds AOA 12k ft AGL for KDUG. Isold TSRA/SHRA in Cochise County
for KDUG through 29/05Z. SWLY-SLY SFC winds through 29/06Z with
speeds btwn 10-15 kts. SFC winds become light and variable through
the overnight period before becoming SWLY aft 29/17Z with speeds
ranging btwn 12-20 kts. Occasional afternoon wind gusts up to 30 kts
from TSRA/SHRA outflows. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...High temperatures will be above average into early
next week. Min RH values will be in the 5-10 percent range in the
lower elevations and between 10-18 percent in the mountains
through the weekend. An exception to this for areas east and
southeast of Tucson today and Thursday where minimum RH values may
climb into the 20 percent range with outflows from thunderstorms
temporarily pushing deeper moisture up from Sonora. Scattered
thunderstorms will be possible this afternoon and evening in
Cochise County, with strong erratic outflows and dry lightning the
main threats. 20-foot wind speeds will continue to remain
elevated through Thursday at 10-20 mph at most locations during
the afternoon and early evening hours. Friday winds stay elevated
mainly east of Tucson. Over the weekend winds will be terrain
driven with normal afternoon gusts due to daytime heating, with
excessive heat possible.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Watch from Saturday morning through Tuesday
evening for AZZ501-502-505.
Excessive Heat Watch from Saturday morning through Monday
evening for AZZ504.
&&
$$
Meyer
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