Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/28/23
Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
547 PM CDT Tue Jun 27 2023
...New AVIATION...
.MESOSCALE UPDATE FOR WIND AND HAIL THREAT FOR THIS AFTERNOON
THROUGH THIS EVENING...
Issued at 212 PM CDT Tue Jun 27 2023
* Synoptic Overview: Upper level high pressure remains in place
across central Texas through tomorrow morning. This is leading to
the main axis of the H500 ridge being just to the east of the
Panhandles early this afternoon. The latest H500 RAP analysis
shows a subtle shortwave trough currently located over eastern New
Mexico. This shortwave is forecast to move northeast later today
and the PVA associated with this wave should kick off
thunderstorms this afternoon through this evening.
* Mesoscale: Based on 18z surface analysis, a surface trough is
currently oriented across the far southern Texas Panhandle early
this afternoon. With southwesterly winds across the southwestern
Panhandles, drier air is moving across this area. Further east,
lower 70s dew points are now moving in across the eastern TX
Panhandle with the winds remaining out of the southeast. These
higher dew points will continue to fill in further north and west
this afternoon. These higher dew points should lead to MLCAPE
values of around 3500-4000 across the northeast by early this
evening. Effective shear around 50 kts is expected as a LLJ will
slowly begin to form this evening into the overnight hours. Main
concern will be capping across this area, with most model forecast
soundings suggesting this will be in play. In any case, sufficient
instability and shear will be across portions of the Panhandles
(favoring the northeast) for at least a few strong to severe
storms late this afternoon through this evening. Across the
western TX Panhandle, instability and shear will not be as
prevalent, but with enough lift, a few storms may still develop in
this environment. The main concern will be damaging winds with
DCAPE values around 1800-2000 J/kg.
* Threats: The primary hazards with the storms today will be
damaging wind gusts (up to 75 mph) and large hail (up to 2 inches
in diameter). For any storms that develop across the TX Panhandle,
the main hazard would the damaging wind gusts, but cannot rule out
some hail with these. The higher threat for both damaging winds
and very large hail will be across the central and eastern
Oklahoma Panhandle as storms move southeast out of Kansas.
* Timing & Location: Scattered thunderstorms may begin to develop
across eastern NM and western TX by mid to late afternoon today.
The more concerning storms may begin to develop across southeast
CO/southwest KS around this same time. These storms will
generally move east and should be out of the Panhandles by late
this evening.
Muscha
&&
.SHORT TERM ...
(This evening through Wednesday night)
Issued at 212 PM CDT Tue Jun 27 2023
For today`s severe weather threat, refer to the Mesoscale
Update above.
Hot temperatures are expected today and tomorrow across the
Southern High Plains. Highs in the upper 90s to triple digits are
expected both this afternoon and tomorrow. Thunderstorms are
possible this afternoon, favoring the northern Panhandles, and
there may even be a small chance again tomorrow afternoon in the
northwest.
So far today, surface temperatures are continuing to increase into
the low to mid 90s at the time of this writing. With areas in the
southwest mixing out, dew points are dropping in this area with
drier air moving in from the west and southwest. A shortwave will
crest the top of the ridge this afternoon into this evening and
sufficient moisture will be in place to generate thunderstorms. In
addition, the convective temperature may be reached for some
locations today and that could generate a couple more storms. With
the warm air mass in place over the Panhandles overnight,
temperatures will remain on the warm side and lows tomorrow
morning will only be in the mid 60s to lower 70s.
The main axis of the H500 ridge will slide off to the east
tomorrow. This will displace the warmer H850 temperatures a bit
further east, but the temperatures may still remain in the 32-34 C
range over the Panhandles. Another day of widespread highs in the
triple digits is expected across the area, except for the
northwest where highs in the upper 90s are currently forecast.
With the main axis of the ridge moving off to the east, another
ridge riding shortwave will move across portions of the Southern
Plains tomorrow afternoon. Some guidance suggests that any storms
that form from this wave may reach as far east as the northwestern
TX Panhandle and the western OK Panhandle. If any storms do make
it this far east, they likely will not be great rain producers as
surface moisture will be very low tomorrow (dew points in the low
to mid 40s). Strong downburst winds will be possible along with
some light rain accumulation. Another night of warm overnight lows
should be expected on Wednesday night due to the hot daytime
highs.
Muscha
&&
.LONG TERM ...
(Thursday through next Monday)
Issued at 243 PM CDT Tue Jun 27 2023
A shift in the jet stream pattern takes place during the long term
forecast period. High pressure transitions over the central Gulf
Coast and an upper trough in the jet stream sets up over central New
Mexico. This will allow for a reduction in high temperatures and
multiple chances for thunderstorms in the coming days.
On Thursday, Highs across the CWA will be in the upper 90`s and
perhaps a few triple digits in the southeast Texas Panhandle. Then
later on in the evening, thunderstorms could form along a surface
trough and enter into our area from New Mexico and Colorado. Mid
range model guidance still has some disparities in how far the
line of storms could travel southeast, so we have let the NBM give
the northwest Panhandles slight chance pops for Thursday evening
through the night.
Later on through the extended, each day has a chance for pops as
temperatures decrease from 90`s to upper 80`s. We have let the NBM
continue with it`s coverage considering any slight upper level
pattern change could influence timing and location for
precipitation each day. Also, if long range models continue with
westerly flow during the weekend, the severity of thunderstorm
activity could become a topic of concern.
Rangel
&&
.AVIATION...
(00Z TAFS)
Issued at 544 PM CDT Tue Jun 27 2023
Thunderstorms will likely affect the TAF sites this evening with
gusty winds the main threat. Skies are expected to remain VFR
outside of thunderstorms. Southerly winds will pick up into the 15
to 20 knot range after sunrise with higher gusts.
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 74 101 72 97 / 10 0 0 0
Beaver OK 68 101 71 98 / 60 0 0 0
Boise City OK 66 97 68 93 / 20 10 10 0
Borger TX 74 105 74 100 / 20 0 0 0
Boys Ranch TX 71 103 71 98 / 10 0 0 0
Canyon TX 73 101 71 96 / 10 0 0 0
Clarendon TX 74 103 73 98 / 0 0 0 0
Dalhart TX 66 98 66 94 / 20 10 10 0
Guymon OK 69 100 69 96 / 30 0 10 0
Hereford TX 71 101 70 97 / 0 0 0 0
Lipscomb TX 69 103 72 98 / 30 0 0 0
Pampa TX 73 102 73 97 / 20 0 0 0
Shamrock TX 74 103 73 98 / 10 0 0 0
Wellington TX 74 105 73 100 / 0 0 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory until 9 PM CDT this evening for TXZ317.
OK...None.
&&
$$
SHORT TERM...05
LONG TERM....55
AVIATION...15
Area Forecast Discussion
National Weather Service Burlington VT
1042 PM EDT Tue Jun 27 2023
.SYNOPSIS...
A slow moving system will continue to provide the North Country with
scattered showers and embedded thunderstorms through Wednesday
afternoon. Once again some localized heavy rainfall will be possible
within any thunderstorm develop, which could lead to localized
flooding. A brief period of relatively dry weather is anticipated
for Thursday and Friday, before more showers and thunderstorms are
expected for the upcoming weekend. Temperatures will hold near
normal through the rest of the week.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 1042 PM EDT Tuesday...We have seen numerous thunderstorms
slide northward through the St. Lawrence Valley this evening
along an occluded front. While there were a couple of stronger
variety storms among them, mainly saw lightning and very heavy
rain leading to several footprints of 1-1.5" of rain. However,
this rainfall has been a manageable amount for this relatively
flat area. With continued surface convergence, warm and moist
low level air will sustain instability (MUCAPE near 750 J/kg) in
this area for another couple of hours. Additional showers with
minimal thunderstorm chances will ride northward from decaying
thunderstorms into the Adirondacks and Champlain Valley
overnight. Overall, forecast is in good shape with only minor
changes needed. While pockets of fog are possible tonight,
especially in northeastern Vermont where combination of
widespread rain late this afternoon and lighter winds will be
present, think dense fog will be hard to come by with plenty of
wind just above the surface.
Previous Discussion...
Water vapor indicates a rather complex mid/upper lvl pattern
acrs the ne conus this aftn with deep conveyor belt of rich
moisture advecting into parts of VT, while dry pocket aloft
impacts western cwa. Best forcing from embedded vort in the flow
aloft and associated jet max wl lift northeast of our eastern
cwa btwn 22-00z, which should result in less areal coverage of
precip for VT by evening. Meanwhile, another vort associated
with mid/upper lvl circulation wl approach SLV by 21z, helping
to redevelop additional convection. Given some weak sfc based
instability of 800 to 1400 J/kg, a few stronger/isolated
convective elements are possible from 21z to 01z this evening.
Have continued with previous forecasters idea of gusty
winds/small hail possible, but feel svr threat is very minimal
attm. Also, based on crnt laps sfc based CAPE fields, have
trimmed back areal coverage of enhanced wording, as clouds are
impacting sfc heating. As instability wanes from the loss of sfc
heating, anticipate areal coverage of showers/storms to
decrease after 01z acrs our cwa and tried to trend
pops/convective elements toward that thinking. Soundings still
indicate good bl mixing with winds of 8 to 14 knots anticipated,
which should limit areal coverage of fog. Some llvl stratus
with areas of mist possible, especially higher trrn of
central/eastern VT, including parts of the NEK overnight. Lows
generally in the upper 50s to mid 60s.
Another relatively active day is anticipated on Weds with increasing
areal coverage of showers and embedded thunderstorms anticipated
with localized heavy rainfall a concern. Our very slow moving
mid/upper lvl trof wl be acrs the SLV, while the associated sfc
boundary is slowly shifting from west to east acrs our region. The
primary focus for pops/qpf based on position of boundary and
placement of mid/upper lvl trof wl be from the dacks into VT. Once
again svr threat looks very marginal as best 0 to 6 km shear is
displayed well to our east and instability is limited by
development/persistent of clouds. Latest 12z NAM and HRRR indicate
axis of 800 to 1400 J/kg of CAPE building into VT btwn 15z-18z,
before clouds/convection develops and stabilizes atmosphere. The
tall skinny CAPE profiles, with pw values around 1.5 and slow moving
boundary support the idea of localized heavy rainfall possible,
especially with Equilibrium lvls btwn 30 and 35kft. WPC continues
with marginal for their ERO, which after some internal coordination
maybe updated to SLGHT for parts of VT with their overnight package
for Weds , based on rainfall foot print from today. Feeling highest
potential for localized flooding would be central/southern VT,
including portions of the Green Mtns. Temps warm into the mid 70s to
lower 80s, very similar to today, as clouds wl limit sfc heating
once again.
For Weds night, axis of best moisture/forcing slowly shifts into the
NEK of VT by 12z Thurs, as precip decreases. Wind fields are
generally light and variable overnight, so given potential for
plenty of llvl moisture, expect areas of dense fog wl be possible.
Lows generally in the mid 50s to lower 60s.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 351 PM EDT Tuesday...Expectation for Thursday is that slow-
moving mid-level trough and associated vorticity maximum will shift
across eastern VT by mid- day, and across northern NH and
northwestern ME during the afternoon hours. Low-level wind fields
are weak with little air mass change. However, should see best
synoptic support for showers shifting east of most of the forecast
area. As a result, limited PoPs to 20-40% from the Champlain Valley
wwd, with PoPs 40-60% across central and eastern VT. Low 60s
dewpoints will contribute to modest instability (SBCAPE around 500
J/kg) across central/ern VT, and limited thunderstorm mention to
those areas. Partly sunny conditions and 850mb temperatures around
+12C should yield valley highs in the mid- upper 70s, with a few 80F
degree readings possible in the Champlain or CT River valleys.
Thursday night should be relatively tranquil with any showers ending
during the evening hours. Weak p-gradient in place with winds
becoming light and variable. May approach crossover temperatures
overnight, and with moist soil conditions, may see some patchy fog
development. Overnight lows mainly upper 50s to lower 60s, except
mid-50s for the northern Adirondacks.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 351 PM EDT Tuesday...Mid-level weakly cyclonic flow will
prevail across NY and New England Friday and Saturday. Appears mid-
level trough north of the Great Lakes sharpens slightly in 12Z
ensemble and deterministic guidance Sunday and into Monday of next
week. Overall pattern supports moderate humidity (dewpoints in the
60s) with valley highs in the low-mid 80s each day. Only modest
support for isold showers on Friday afternoon, but should see
increasing large-scale support for scattered showers and
thunderstorms both Saturday and Sunday afternoons and have indicated
some highest PoPs (50-60%) both afternoons. With PW values remaining
high (1.6-1.8" per 12Z GFS), may see some locally heavy downpours
with any convective storms/stronger cores. Maintained 30-40% PoPs
for additional showers and thunderstorms Monday into Tuesday next
week.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...Showers have exited Vermont leaving
breaks in cloud cover ahead of isolated to scattered
showers/thunderstorms moving through northern New York along a
surface trough. Some MVFR/IFR mist/stratus will be possible for
Vermont terminals given the amount of moisture that has fallen.
Otherwise, next precipitation chances will follow the surface
trough from 01-05Z for MSS/SLK, 07-10Z for PBG/BTV, then this
washes out. Another line of showers/thunderstorms is expected
along a frontal boundary that will pass through the region
12-21Z moving west to east. Some of these storms may be strong,
but heavy rain continues to be the primary threat and will
likely result in periods of IFR/MVFR CIG/VIS. Winds shift
westerly behind the front with conditions beginning to dry and
skies starting to clear. Radiation fog/stratus will likely
become widespread after 00Z Thursday.
Outlook...
Wednesday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Thursday: Mainly VFR, with local MVFR possible. Chance SHRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR. Slight chance SHRA.
Friday Night: VFR. Chance SHRA.
Saturday: VFR. Chance SHRA, Chance TSRA.
Saturday Night: Mainly VFR, with local IFR possible. Likely SHRA,
Slight chance TSRA.
Sunday: Mainly MVFR, with areas IFR possible. Likely SHRA, Slight
chance TSRA.
&&
.HYDROLOGY...
Localized heavy rainfall continues to impact parts of the
central/southern VT, including the Champlain Valley this
afternoon. Rainfall estimates of 1 to 2 inches have been
observed, with localized higher amounts, which combined with
recent heavy rainfall has created areas of very saturated ground
conditions. While widespread flooding is anticipated, another
round of showers with embedded thunderstorms with localize heavy
rainfall is likely for Wednesday. The primary threat for heavy
rainfall will be across the Adirondack Mountains into most of Vermont
from late morning into early evening on Wednesday. Given recent
rainfall the 1, 3 and 6 hour flash flood guidance is 1.25 to
1.50, 1.50 to 1.75, and near 2.0 inches respectively in the
lowest areas in our region. Our thinking the highest potential
for isolated hydro related issues on Weds would be across
central/southern VT mtns into parts of the CPV. WPC continues
with MRGL for ERO, which may be upgraded to SLGHT for day 1
depending upon how this evening plays out.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Kutikoff/Taber
SHORT TERM...Banacos
LONG TERM...Banacos
AVIATION...Boyd/Taber
HYDROLOGY...Taber
Area Forecast Discussion
National Weather Service State College PA
1122 PM EDT Tue Jun 27 2023
.SYNOPSIS...
An upper trough axis will push east of the area tonight, and
a drying trend is expected Wednesday into Thursday. Showers and
thunderstorms will end June and kick off the month of July.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
Trough axis passing overhead. Last few TSRA were moving SSE,
certainly a deviation from the earlier cell motions. The rest of
the SHRA across the nrn tier and Alleghenies are low-topped and
light. The coldest of the air aloft will keep these SHRA going
for much of the night. The clouds should start to break up in
the lee of the mtns in the next few hrs. The nearly solid deck
of clouds to our NW and the upslope into the Alleghenies should
keep it pretty cloudy there all night. Even with the clouds and
some wind, fog is probable, esp in the areas where it can clear
out. The clouds touching the ridge tops in the W and N will make
it foggy there, too. Upstream vsbys are in the 2-5SM range
already. So, we`ve kept on with the mentions of fog. Interesting
to see reports of smoke already in the obs all over Lower
Ontario and nrn OH and Lower Michigan. The smoke is headed this
way, but may only get into the wrn mtns and not too far into the
CWA on Wed.
Low temps tonight will be in a fairly tight range from NW to SE
and in the mid 50s to low 60s as more upslope stratocu cloud
cover is expected to persist through the night.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Upper trough axis will be just east of the CWA by 12Z Wednesday
with gradually improving conditions after early morning fog and
low clouds.
Western edge of the cooler mid level temps and marginal
instability will be over our NE zones Wednesday afternoon and
this will keep the chance for a few afternoon showers in the
forecast. Lowest POPS will be over the Scent Mtns where slightly
warmer air aloft/building heights and downslope northwesterly
LLVL flow will be present.
High temps Wednesday will be a solid 5-8 deg F below normal,
with mid to late afternoon temps ranging form the upper 60s to
low 70s over the northern and western mtns to the upper 70s in
the Lower Susq Valley.
Clearing and cooler temps with patchy fog is expected for Wed
night/early Thursday as sfc high pressure becomes centered over
the state. Temps will dip into the upper 40s in the perennial
cold spots across the NW Mtns and Somerset County, and will
range through the low and mid 50s in the Central Ridge and
Valley Region with Low 60s in the SE Metro Areas.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
The 11 PM update yields only slight upticks in PoPs for much of
the period, but most notably on the 4th where 30-40 PoPs have
crept in for diurnal showers/storms with perhaps a secondary
trough lagging behind the main cold front.
Prev...
Summer like pattern with mild and dry weather on Thursday with
trough pulling out. But weather will turn unsettled for the
weekend as next trough approaches, bringing a shower and
thunderstorm chances each day over the weekend. Most of the
convection will be diurnally driven. Frontal passage is likely
by Monday with drying conditions expected on Independence Day.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A moist upslope flow beneath an upper level trough will result
IFR/LIFR cigs across the W Mtns tonight, while a downsloping
west flow yields progressively higher cigs east of the spine of
the Appalachians. Breaking clouds and light wind behind an
exiting cold front could potentially result in areas of fog
late tonight across the Susq Valley, mainly east of KMDT.
Diurnal heating will result in rising cigs Wednesday. Model RH
profiles support VFR cigs over most of central PA by afternoon.
However, can`t rule out MVFR cigs lingering into the PM hours
over the W Mtns. Also, will have to watch plume of smoke from
Canadian wildfires. The latest HRRR Smoke Model suggests high
IFR/low MVFR vsbys are possible Wed afternoon over the NW Mtns,
which could potentially arrive over the central part of the
state by evening.
Outlook...
Thu...Patchy AM valley fog likely, mainly N and W Mtns.
Fri...Isold PM tsra impacts possible.
Sat...AM low cigs possible, esp central Mtns. Sct PM tsra
impacts possible.
Sun...AM low cigs possible, esp N Mtns. Sct PM tsra impacts
possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert
NEAR TERM...Dangelo
SHORT TERM...Lambert
LONG TERM...Ross/Dangelo
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Cheyenne WY
515 PM MDT Tue Jun 27 2023
.SHORT TERM...(This evening through Wednesday)
Issued at 310 PM MDT Tue Jun 27 2023
Threats in the short term deal with severe thunderstorms this
afternoon/early evening and once again Wednesday.
Currently...Frontal boundary lays along a line from Kimball to
Wheatland westward to Rawlins this afternoon. SOuth of the
front...very dry air with gusty west winds. North and east of the
front...a much juicier airmass with dewpoints in the low to mid
60s from Sidney to Chadron to Torrington. Mid 50 TDs up near
Douglas. Current RAP MUCAPE from SPC Mesoanalysis page showing
near 5000J/KG across Cheyenne County...with 3000-3500J/KG up into
the southeast WYoming Plains into Niobrara County. A Severe
Thunderstorm Watch #403 has been issued for these areas north of
the front this afternoon into early evening.
For the rest of this afternoon and evening...generally followed
the HRRR`s guidance...which shows a couple discrete supercells
developing here shortly. One across northern Goshen into Niobrara
and another down in Banner and Scottsbluff Counties. These storms
look to move fairly quickly east through 00Z and end completely by
01Z/02Z. Similar to yesterday...0-6km shear will be quite high
with this high CAPE...so all modes of severe convective weather
will be possible.
On to Wednesday...A more widespread convective event possible as
upper vort energy traverses through the CWA from the southwest.
Surface boundary begins to shift back to the southwest with PWATS
rising back above 1 inch across the northern Panhandle to Platte
and Goshen Counties Wednesday afternoon. Looks like Cheyenne and
Laramie will remain in the dry air...but points north and east
will see increased convection. GFS forecast soundings Showing
MUCAPE above 2000J/KG across the northern Panhandle with 0-6km
shear 40-45kts|. Will likely be seeing increased coverage across
Converse and Niobrara as well as the northern Panhandle.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 310 PM MDT Tue Jun 27 2023
Boundary for Thursday and Friday looks to shift west and lays
along a line from Laramie to maybe Muddy Gap. PWATS up to and over
an inch east of the Laramie Range and near .5 inch in Carbon
County. May need a Flash Flood Watch for THursday and Friday as
model output on QPF showing very heavy 6 hour QPF on both the GFS
and ECMWF. Will deal with that tomorrow. Upper trough moves into
western Colorado with an 80kt 250mb jet over the CWA. Would think
we will be dealing with heavy rain as well as severe
thunderstorms. CAPE and shear will be there for severe storms both
days.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 513 PM MDT Tue Jun 27 2023
Storms coming to an end shortly after 01Z to 02Z in the Nebraska
Panhandle. Some concern for IFR around KCDR as winds turn
northeast. Used timing from HRRR for IFR onset at KCDR. VFR
elsewhere as winds ease. Thunderstorms return Wednesday
afternoon...especially east of the Laramie Range.
&&
.FIRE WEATHER...
Issued at 310 PM MDT Tue Jun 27 2023
Critical fire weather conditions ongoing this afternoon as
humidities fall below 10 percent along and west of the Laramie
Range. Westerly winds have been gusting as high as 40-45 mph over
the I-80 Summit and across Carbon and Albany Counties this
afternoon. Fortunately...fuels are reported still green...so fire
weather headlines are not needed. Wetter conditions as moisture
returns Wednesday. The exception being southern Carbon and Albany
Counties that will still see low humidity and gusty winds.
Increasing moisture Thursday as a surface boundary sags into the
area from the northeast. This boundary will be the focusing
mechanism for fairly widespread wetting rains and thunderstorms
that will persist through Friday. Unless fuels change today or
Wednesday...no fire weather concerns are expected.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Dodge City KS
637 PM CDT Tue Jun 27 2023
...Updated Mesoscale Discussion...
.MESOSCALE DISCUSSION...
Issued at 631 PM CDT Tue Jun 27 2023
Thunderstorms increasing in coverage as they move northeast across
the panhandles of Texas and Oklahoma. Expect this trend to
continue as these storms move northeast into an area of higher low
level moisture. Latest HRRR now appears a little more reasonable
keeping with storms increasing in coverage as they move northeast
into southern before taking a more easterly track along the
Kansas/Oklahoma border after 01z as a weak upper level wave moves
across southwest Kansas. Until now the warm +16C 700mb
temperatures have limited convection across extreme southwest
Kansas but this may change over the next several hours as the
convection encounters an area of higher low level moisture. The
area of interest between 00z and 03z for the best opportunity for
large hail and strong damaging winds will be south of Dodge City
and West of Ashland given the low level moist axis, forecast deep
layer shear and mid level lapse rage. Further north and east a
more stable environment will exist. Not saying strong winds and
hail will not occur in these areas but the probability is much
lower than what was previously expected earlier this evening.
Current severe thunderstorm watch still looks on track but am now
favoring locations close to the Oklahoma border as having the
highest probability for very large hail and wind gusts of 75 or
greater. Also along the Oklahoma border will also be monitoring a
window of opportunity for a tornado or two given the increasing
low level wind shear that will be between around sunset.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 212 PM CDT Tue Jun 27 2023
A significant boost in dew points was observed in the last 24
hours across the far western counties. The easterly upslope flow
over the greater area of the DDC warning area was cutoff on the
western periphery by a warm front in extreme eastern Co and
extending southeast to just north of Elkhart, KS. That area of
moisture pooling and convergence will serve as the better
initiation zone for supercells by mid to late afternoon, with the
high cape and shear axis eastward across the southern half of the
DDC forecast area providing the best combination for sustained
supercells producing hail, wind and isolated tornado risk through
early evening. The latest HRRR runs have had a consistent (hour to
hour) disposition to high end winds across the OK/KS state line,
coinciding where the moderate risk was drawn up by SPC. High
values of the Large Hail parameter already exist along and ahead
of the warm front, outlining the area of greatest 3 inch hail risk
in our western counties, although hail will be a risk across the
entire area through mid evening. We did use the FV3 for the
official grids for a better timing of stronger convectively
induced winds rather than the diluted NBM values. These will need
to be assessed through the evening as the convection unfolds. The
consensus of the convective allowing models takes he supercells
from just ahead of the warm front near near Syracuse and the
highway 25 corridor between 21 and 00 UTC, and the right turners
morph into a small MCS , southeast along the OK/KS line, south of
highway 400 exiting the Pratt/Medicine Lodge area after 2 or 3
UTC. The cold convective outflow will drop temps into the mid 60s
quickly. Secondary areas of higher winds in the CAMs could be
evaporatively cooled over turning in high lapse rates nera the
MCS anvil edge late in the evening, (surprise brief high winds
after the storms).
Much of Wednesday’s severe weather potential will probably depend
of the outcome of this afternoons and evening’s severe weather
event including where stable outflow air sets up and creates or
destroys surface moisture and theta-e convergence. We’ll still
have the upper jet nearby while the ECMWF/GFS show high surface
dew points pooling behind a weal surface cold front or previous
day outflow to the northwest of the exiting surfaces low. Any
severe risk is anticipated to be far from the higher end threats
we are seeing this afternoon, and probably limited to gusty to
marginally damaging wind.
.LONG TERM...(Thursday through Tuesday)
Issued at 212 PM CDT Tue Jun 27 2023
The longer term looks a little more uncertain with day to day
convection as the the official outlooks are showing not enough
confidence to draw up and risk areas. That said, we do have a
positive tilt upper trough axis moving very slowly southeast
Thursday into Friday across the Great Basin and with a jet axis
lifting through the southern and central Rockies via
EC/GFS/Canadian global models. This shows potential for storms off
the higher terrain any given day, but a more pronounced
widespread convective signal as the upper jet gets closer to
Kansas by Friday or Saturday. Highest chances for widespread
thunderstorms right now are Friday night, which will also tend to
temper the hot temperatures in the 90s to around 100 expected
Wed/Thursday to not as hot 80s for the weekend. The 6 to 10 day
CPC outlook shows a broad area of the Rockies and central/southern
Plains in the “leaning above” precipitation category – or more
specifically a 40 to 50 percent chance of above normal
precipitation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 621 PM CDT Tue Jun 27 2023
Recent analysis from the last short term model runs as well as
the current trends has increased the uncertainty in the strongest
winds impacting the northernmost terminals. As a result, the
strongest winds have been decreased some in the TAFs as the HRRR
analysis has a more stable airmass near the surface. As
cyclogenesis is ongoing, the surface CAPE should still increase
into the evening, rendering the still strong possibility for severe
storms in the area, but the areal coverage may not be as great as
earlier thought. We may need to amend TAFs on an hour by hour
basis though the evening as the storms develop.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 100 70 98 / 80 0 10 0
GCK 65 97 67 95 / 70 0 20 0
EHA 68 100 69 95 / 50 10 10 0
LBL 68 100 69 97 / 90 0 0 0
HYS 66 98 69 99 / 30 0 20 0
P28 71 103 74 103 / 80 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE...Burgert
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Russell
Area Forecast Discussion
National Weather Service Duluth MN
643 PM CDT Tue Jun 27 2023
.DISCUSSION...(This evening through Monday)
Issued at 246 PM CDT Tue Jun 27 2023
Summary: Periodic showers and thunderstorms through the week with
a gradual warm up. Smoke from the Canadian fires will continue to
drift through the area through at least Thursday afternoon.
Radar shows showers and thunderstorms that have developed over
the western portion of the area this afternoon. This is a result
of a shortwave that is traveling along the periphery of the upper
level ridge centered over central TX. As this area moves into
Canada, showers and thunderstorms are expected to follow ending
the chances over the portion of MN this evening. Not expecting
much in the way of severe weather due to limited shear and little
upper level support.
A secondary shortwave is expected tomorrow morning. This again
will spark off showers and thunderstorms for the region. Limited
shear will be available therefore severe weather is not expected
initially. By the afternoon, the shortwave is expected to
strengthen. Additionally, shear will increase to about 30 to 40
knots south of a line from Leach Lake to Duluth. MLCAPE of around
1000-1500 J/kg will skirt along the southern border of the CWA.
Therefore, SPC has a marginal risk for the southern counties with
a slight risk just outside the CWA. Large hail and damaging winds
are possible. QPF will be around 1.5", therefore with the limited
shear initially, showers and thunderstorms will be somewhat slow
moving. This could lead to heavy rain at times and localized
flooding. Into the afternoon, showers and thunderstorms could
again cause localized flooding as the rain soaked area from the
morning will again be exposed to heavy rain. WPC does has a
Marginal Risk for Excessive Rainfall. There is concern that cloud
cover tomorrow afternoon will limit the instability. This could
suppress the severe weather to along the southern border of the
CWA and just outside of it.
Thunderstorm chances continue into the remainder of the week as
an upper level low pressure system drops down from Canada into
far northern MN eastward into the MN Arrowhead. Instability will
be minimal therefore severe weather is not expected.
Smoke from the Canadian fires have drifted into the CWA and
should remain through at least Thursday. An Air Quality Alert has
been issued for both MN and WI due to these fires. Some areas
have seen HZ therefore have added that to the grids for visibility
and Smoke to the sky using HRRR data.
Temperatures tomorrow will dip slightly below normal as cloud
cover will hinder any opportunity of a warm up. Temperatures will
rebound on Thursday and gradually warm up through the weekend to
the low 80s by early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 642 PM CDT Tue Jun 27 2023
A rather messy forecast this evening as scattered showers and
thunderstorms are occurring especially across northeast Minnesota
but beginning to spread into northwest Wisconsin. A more steady
rain is expected at INL for the next hour or two before
diminishing. A brief break is expected at HIB for about an hour,
but more showers and possibly storms may affect the terminal later
this evening. The lake breeze may keep most storms away from DLH,
but a few showers may pass through this evening. An area of
showers and storms may affect HYR over the next several hours
before ending. Expect VFR conditions for most of the night at BRD
as convection has moved east and is not expected to redevelop.
With the scattered nature of the showers and storms and associated
outflow boundaries, variable wind directions can be expected this
evening and gradually becoming more southerly tonight. A bit of
fog is possible later tonight at some terminals with MVFR
visibilities possible. A broader area of rain and possibly some
embedded thunder is likely to pass through the region Wednesday
morning, leading to some MVFR ceilings and possibly reduced
visibilities. There is uncertainty on Wednesday afternoon`s
forecast as it will be dependent on lingering cloud cover, but if
skies do clear out enough, some thunderstorms may develop.
Isolated strong to severe storms capable of producing hail up to
around 1 inch and wind gusts up to around 60 mph will be possible.
&&
.MARINE...
Issued at 246 PM CDT Tue Jun 27 2023
Quiet weather continues into the overnight hours with winds
decreasing to less than 5 knots. Waves will be less than a foot.
Winds are expected to increase tomorrow afternoon out of the
northeast at 10 knots with gusts to near 15 knots. Waves will
increase to 1-2 feet. Showers and thunderstorms will move in to
the afternoon. Some storms could produce hail and cloud to water
lightning. Fog will develop over the lake similar to this morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 55 66 55 77 / 50 90 70 50
INL 59 72 58 77 / 70 90 70 80
BRD 62 75 61 82 / 80 80 40 40
HYR 58 74 58 82 / 40 90 80 60
ASX 54 70 58 78 / 40 80 80 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
DISCUSSION...KSE
AVIATION...JDS
MARINE...KSE
Area Forecast Discussion
National Weather Service Quad Cities IA IL
620 PM CDT Tue Jun 27 2023
...00z AVIATION UPDATE...
.SHORT TERM...(This evening through Wednesday)
Issued at 202 PM CDT Tue Jun 27 2023
Key Messages:
1) Wildfire smoke continues to push through the area today and
through tomorrow, with levels reaching unhealthy to hazardous in
most locations!
2) Marginal Risk for severe weather tomorrow, with main hazards
being hail and wind.
This Afternoon Through Tomorrow...
Wildfire smoke moved in with higher concentrations than initially
forecast, leading to unhealthy-hazardous air qualities throughout.
So, we have an Air Quality Alert for this through Wednesday. The
smoke is very dense and has made it to the surface. Thus, it has
also resulted in lower temperatures than initially forecast. We
are currently hovering in the upper 70s for most, with some in the
low 80s.
For the most part, this afternoon and much of tonight will remain
quiet. One thing that we have our eyes on is the smoke that has made
it`s way into the area. Unfortunately, we have trended worse than
initially forecast and much of the area is now either Unhealthy to
Hazardous for all. With higher concentrations present at the
surface, we will smell the smoke, rather than it just painting the
sky white. So, if you are working outside this afternoon and
evening, please be cautious and take regular breaks indoors.
Tonight, smoke will remain aloft and clouds will start to move into
the area from the west. A weak upper wave rides the top of the ridge
and moves through our area late tonight and through tomorrow
morning. This pattern is what we consider the "Ring of Fire", where
there is a dome of high pressure and if the environment is
favorable, we get overnight MCSs that pass through the area. While
not a strong upper wave, it is possible to see some showers and
storms late tonight, but has started to trend closer to the
morning hours. So, most of the night will be dry, with
temperatures in the 60s and winds shifting southeasterly.
Tomorrow, the aforementioned wave passes through the area, bringing
along the chance for showers/storms. In the morning, we should be
dealing with an elevated and decaying complex of storms. Thus, the
severe threat should be low. Although, we do have a Marginal Risk
for Severe Weather tomorrow. This severe chance seems to focus with
some of the early convection, with the threat of damaging winds and
hail being the focus. Surprisingly, there is much uncertainty
amongst CAMs with this situation, especially with timing. Latest
HRRR run brings the dying line of convection through prior to
sunrise tomorrow, while other guidance brings it through in the
mid- morning to early afternoon. The HRRR also allows for storms
to initiate again tomorrow afternoon, as it brings the complex
through earlier and allows us to heat up more. For example, it
brings areas along and south of Highway 34 near/over 100 degrees.
Confidence is very low on this, as it is an outlier and is just
too warm. Thus, our forecast does not reflect this hot solution.
If we trend with a later solution on timing, this would leave us a
little cooler than guidance, as we would likely be dealing with
remnant clouds from the complex. Thus, this would kill the chances
for convective activity through the day. Otherwise, we are
expecting a warm and breezy day tomorrow, with temperatures in the
mid 80s and gusts upwards to 20-30 mph.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 202 PM CDT Tue Jun 27 2023
Key messages:
1) Marginal risk for severe storms Wednesday night.
2) Slight risk for severe storms Thursday.
3) Active pattern into the weekend.
Details:
Wednesday night: LLJ/warm air advection increases across much of the
forecast area. Scattered thunderstorms should develop in this WAA
zone and there is the potential for a few storms with large hail and
damaging winds the main threat.
Thursday: SPC has a slight risk for severe storms east of the MS
River with a marginal risk in eastern Iowa. Heat dome will exist
across the lower/mid MS Valley where very hot temps will reside.
This puts the forecast area on the edge of this heat dome (ring of
fire) with strengthening mid level winds. What needs to be figured
out is the timing and location of any thunderstorm complexes or
MCS`s moving across the area. Highs in the upper 80s north to lower
to mid 90s south.
Friday through the weekend: Periodic rounds of thunderstorms,
possibly strong to severe, is expected but low confidence in
coverage and timing. Upper level trough sweeps across by Sunday so
this should diminish the threat later in the weekend, as we get into
a northwest flow. Highs in the 80s to lower 90s.
Early next week: Ridging builds back into the Midwest so this should
be a very warm and mainly dry period. Highs in the lower 90s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 619 PM CDT Tue Jun 27 2023
Hazy skies from wildfire smoke and high pressure overhead will
persist through tonight into early tomorrow, keeping MVFR to IFR
conditions (mainly visibilities, the smoke is also causing low
ceilings despite no clouds) in place at all terminals. Early
Wednesday morning, keeping a close eye on an approaching
disturbance from the west that has potential to bring a chance of
showers and an isolated storm beginning around 10-11z (confidence
on storms is low and have left mention out of the TAFs at this
time). Later in the period, increasing winds out of the south
with gusts around 20-25 kts should help mix out any low-level
smoke, leading to improving conditions.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SHORT TERM...Gunkel
LONG TERM...Haase
AVIATION...Speck
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
602 PM CDT Tue Jun 27 2023
...Aviation Update...
.DISCUSSION...(This evening through Tuesday)
Issued at 341 PM CDT Tue Jun 27 2023
Key Messages:
* Showers and thunderstorms are expected to develop late this afternoon
into the evening across portions of northeastern Colorado,
western and southwestern Nebraska, and northwestern Kansas,
moving east into our area. There is a Marginal to Slight Risk of
severe weather for much of the Hastings forecast area for
today/tonight, with a small area in our west clipped into an
Enhanced Risk area.
* Wednesday will be the hottest day of the week with highs
primarily in the 90s. A few areas may reach triple digits across
north central Kansas and south central Nebraska.
* Thursday night through Saturday, we`re looking at the potential
for two systems to come through the region, giving us a shot at
some precipitation.
The forecast begins with an upper ridge remaining over the High
Plains today and an upper trough over the western CONUS. Isolated
showers and storms will remain possible this afternoon/early evening
for portions of the area. The higher concern remains with the
potential for thunderstorms developing off of a dryline over eastern
Colorado and western Kansas. The HRRR continues to show storms
developing over western Nebraska/NW Kansas and eastern Colorado,
congealing into a line and moving into the Hastings forecast area
this evening. The NAMNest on the other hand, develops a few cells
and brings them across Nebraska. Despite model differences, any
storms that do develop will be moving into an area with decent
instability and shear. Should any storms develop and make it into
our area, hail up to two inches and damaging winds up to 70 mph will
be possible. Locally heavy rainfall may also be possible with any
storms moving through.
Wednesday, the ridge remains in place over the region, giving us a
shot at triple digit heat in a few locations. Expected high
temperatures range from the upper 80s to low 90s for areas north of
the Tri-Cities. Areas along the I-80 corridor are currently
forecasted to be in the low to mid-90s, with areas south of Highway
6 expected to reach the mid to upper-90s. Portions of north central
Kansas may come close to reaching Heat Advisory criteria. Did not
have a high enough level of confidence to issue an advisory at this
point in time.
Heading into Thursday and Friday, the ridge remains the High Plains
with the upper trough advancing eastward. There will be a couple of
chances for precipitation across our region, with the first one
being Thursday night into the day Friday. This will come as a weak
shortwave moves across the region. The second chance for showers
and storms will be Friday afternoon through Saturday morning as the
upper low lifts to the northeast. Should things stay consistent,
these two events may be our best chance at widespread moisture
across the region over the next several days. High temperatures
will be in the 80s and 90s on Thursday, with a cool down the 80s on
Friday. Lows will be primarily in the 60s. Saturday, the upper
trough is expected to move out of the region. A few isolated
showers/storms may be possible.
Sunday is expected to be dry for much of the day with highs in the
80s. The pattern shifts heading into the start of next week. A few
showers and storms may be possible although confidence remains
fairly low.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 551 PM CDT Tue Jun 27 2023
Breezy conditions are expected to taper off this evening. The
winds will become light overnight. A SFC trough will move through
the TAF sites tomorrow morning and behind the trough expect
northerly winds. Decided to put a mention for VCSH this evening.
Short range models bring some showers across the TAF sites this
evening. Longer range models keep us dry, so have low confidence
in precip tonight, but figured a mention of VCSH is warranted.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Wekesser
AVIATION...Beda
Area Forecast Discussion
National Weather Service Grand Rapids MI
1049 PM EDT Tue Jun 27 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 1045 PM EDT Tue Jun 27 2023
The area buoy reports indicate that the wave heights and wind
values have fallen under hazardous levels. The pressure gradient
is forecast to weaken further tonight so it is unlikely that the
winds or waves will increase. Thus we cancelled the Beach Hazards
Statement and Small Craft Advisory early.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 328 PM EDT Tue Jun 27 2023
Our two forecast challenges in the short term portion of the
forecast will be centered around smoke trends, and shower/storm
chances on Wednesday night.
Smoke from the wildfires in Canada with the flow from the North is
the obvious impact out of the gate this afternoon. The entire area
is seeing and smelling it at the surface layer, with unhealthy
levels per the Air Quality Alert by the Michigan Department of
Environment, Great Lakes, and Energy (EGLE).
Based on upstream obs over Nrn Lower and the UP and the HRRR Smoke
model, we are expecting that the smoke will diminish some late this
afternoon and tonight. It does look like that it will try to make
another run at the area as the flow becomes from the SSE, and bring
the lingering smoke to our South back over the area by late Wed and
Wed night. The Michigan Department of Environment, Great Lakes, and
Energy (EGLE) has issued another Statewide Air Quality Alert for
Wednesday 6/28.
The focus will shift to rain and thunder chances then for Wednesday
night. There is good agreement in the short term models and CAMs
that a MCS is likely to develop over the Upper Midwest late
Wednesday afternoon and evening. The initial development is
generally expected to occur near the MN/WI border. This development
is expected to take place at the nose of a low level jet core, with
a great deal of instability being fed into that area.
The expectation is that the MCS will travel around the ring of the
upper ridge, which would take it into WI, before it would turn SE.
As this entire complex would approach the area, the low level jet
core would be in its typical weakening stage at that time of the
day, and the storms would follow the instability gradient. This
would point toward a few showers and maybe a rumble of thunder here
toward daybreak Thursday morning with some residual warm and moist
advection. The main remnants of the MCS would likely miss us to the
SW and S.
.LONG TERM...(Thursday through Tuesday)
Issued at 328 PM EDT Tue Jun 27 2023
We continue to believe the long term period of Thursday into early
next week will be more on the active side of the spectrum. That line
of thinking is due to an upper pattern that will be zonal with
embedded shortwaves from Thursday into Friday. In addition, over the
weekend a more substantial 500mb shortwave trough will work through
the Great Lakes region. So, from Thursday through Sunday we at least
have some chances for rain in the area. The HREF is indicating
showers and storms moving into our CWA on Thursday morning which
will be in a decaying phase as they move through. 30-50 percent
chances for showers/storms will be common from Thursday through
Sunday. The surface pattern is nebulous with overall a weak gradient
and a lack of significant systems. Surface high pressure takes
control early next week with drier weather. 80s will be common
through the period for highs. Depending on cloud cover on Thursday
and Friday we could make a run at 90 given an 850mb thermal ridge
with temperatures in the upper teens C.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 738 PM EDT Tue Jun 27 2023
Overall the smoke has been fairly steady in terms of impact,
mainly IFR visibilities. Based on the latest trends, it appears
the IFR will persist through the evening. Model guidance suggests
we will see the near surface smoke decrease overnight. We
therefore did feature conditions going to MVFR for some sites.
Smoke will be around Wednesday as well. There is some potential
for it to thicken up again, but that may not happen til later in
the period, so for most sites. The MVFR cloud deck that covered
the TAF sites this afternoon will continue to scattered out this
evening as model guidance shows decreasing humidity in the current
cloud layer.
&&
.MARINE...
Issued at 328 PM EDT Tue Jun 27 2023
The ongoing Small Craft Advisory/Beach Hazards event is progressing
as forecast this afternoon. This event should continue into the
evening, before winds and eventually waves come down.
The other hazard out over the nearshore waters is the smoke from the
Canadian wildfires that is reducing the visibilities down to a mile
or less at times. Consideration was given for potentially needing a
Marine Dense Smoke Advisory with the restriction to visibilities.
Local/regional thresholds for this would be 1/4 mile or less. We are
not seeing any evidence in observations of that, so will just
continue to mention where we can to get the message out.
It looks like the winds will settle down for Wednesday, before they
come up on Thursday. Winds could come up enough on Thursday to
create some Small Craft/Beach hazards.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...MJS
SHORT TERM...NJJ
LONG TERM...Duke
AVIATION...MJS
MARINE...NJJ
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
910 PM CDT Tue Jun 27 2023
.SYNOPSIS...
Issued at 839 PM CDT Tue Jun 27 2023
Hazy and smokey skies from Canadian wildfires will continue
through tomorrow night. Otherwise, highs will be in the mid to
upper 80s, with overnight lows in the 60s. A weather system will
move toward the area and bring much warmer temperatures for
Thursday and Friday, reaching well into the 90s with heat indicies
in the 95 to 105 degree range for both days. This system will also
bring shower and storm chances to the region, with the best
chances being Thursday and into the weekend.
&&
.UPDATE...
Issued at 910 PM CDT Tue Jun 27 2023
Smoke continues to filter into central Illinois on light NE winds
this evening. 02z/9pm visbys generally range from 1 to 3 miles
along/northeast of a Galesburg...to Springfield...to Effingham
line. Based on boundary layer flow and latest RAP/HRRR output,
think visbys will remain restricted through the remainder of
tonight into Wednesday before flow becomes more southerly. Other
than the smoke, expect mild and dry weather tonight with low
temperatures ranging from the upper 50s far northeast around
Rantoul and Danville to the middle 60s southwest.
Barnes
&&
.SHORT TERM... (Through Late Wednesday Night)
Issued at 349 PM CDT Tue Jun 27 2023
The main concern in the short term is the smoke over the area,
creating unhealthy conditions. An Air Quality Alert has already
been issued and this continues through tomorrow night. HRRR sfc
smoke guidance has had a good handle on this already and forecasts
the smoke will remain over the area into tomorrow and then begin
to get pushed northeast as the next weather system moves into the
area. Some precip is possible tomorrow morning, but given we are
still under a drought, would expect the precip to initially dry up
as it moves east across the CWA. A better chance of precip is
possible, but not until late Wednesday night, which should also
wash the rest of the smoke away.
Overnight lows should be in the 60s to around 70 through Wed
night, with daytime highs in the mid to upper 80s.
Auten
.LONG TERM... (Thursday through Next Tuesday)
Issued at 349 PM CDT Tue Jun 27 2023
The pattern will become more zonal into the extended period and
this will allow multiple periods of showers and storms from
Thursday and through the weekend. The storm system on Friday could
bring some stronger storms but severe weather is uncertain at this
time.
Very warm conditions are expected Thursday as well, with highs
reaching into the mid to upper 90s. With dewpoints getting into
the lower 70s, heat indices are expected to reach to around 105 by
afternoon. Warm temperatures are still expected on Friday, but
dewpoints will be on the cooler side, so heat indices are only
expected to reach in the 95 to 100 degree range. Remainder of the
extended period, temps are expected to be the 80s to around 90 for
afternoon highs, with overnight lows in the 60s.
Auten
&&
.AVIATION... (For the 00z TAFs through 00z Wednesday Evening)
Issued at 655 PM CDT Tue Jun 27 2023
Reduced visibilities due to smoke will continue to be the primary
aviation forecast challenge over the next 24 hours. Winds will
initially be N/NE at 5-10kt early this evening, then will veer to
E by midnight, then to SE by mid-morning Wednesday. Given the
tightening pressure gradient, think speeds will exceed 10kt on
Wednesday. Latest visible satellite imagery shows a large plume
of smoke extending from Michigan southwestward into Illinois. The
smoke will remain essentially in place through Wednesday morning
before winds switch to SE and begin pushing it out of the area. At
this time, RAP/HRRR forecasts suggest reduced visbys through
afternoon before a rapid improvement after 00z Thu.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Indianapolis IN
758 PM EDT Tue Jun 27 2023
.Forecast Update...
Issued at 758 PM EDT Tue Jun 27 2023
The primary weather concern in the short term is reduced visibility
and air quality from Canadian wildfire smoke. Since we`re so far
from the source region, the nocturnal inversion may not worsen
visibility substantially. However, it is possible that smoke
particles may enhance condensation nuclei and as relative humidity
becomes high later tonight visibilities may decrease further at some
locations.
As mixing begins tomorrow morning it should help improve visibility
as residual low-level smoke should vertically disperse. Through a
deeper layer, HRRR smoke model shows deformed flow helping
horizontally disperse smoke some lessening its magnitude. Visibility
may not be as low tomorrow as a result.
Please reference the Air Quality Alert Message for further details
on unhealthy air quality.
&&
.Short Term...(This evening through Wednesday)
Issued at 306 PM EDT Tue Jun 27 2023
Currently, half of central Indiana remains under a stratocumulus deck
within broad subsidence. This higher cloud cover has hindered
temperature gains this afternoon with highs remaining in the low
70s. In SW central Indiana, cloud cover has been less, but the smoke
layer has remained, still keeping temperatures in the upper 70s to
low 80s.
As mentioned, a smoke layer has encompassed all of central Indiana
leading to hazy skies, reduced air quality, and lower visibilities.
This is expected to continue as N/NNW flow remains over the region
behind the departing low. There is some uncertainty with how
concentrated the smoke layer will be tonight as subsidence builds
beneath upstream ridging. At a minimum visibilities should remain at
or below 4 miles, but reductions to 1 miles are possible depending
on how shallow the inversion gets.
Smoke plume models indicated a more concentrated layers of smoke
will enter central Indiana late tonight into tomorrow, continuing
the hazards of reduced visibilities and air quality. Temperatures
are likely to be suppressed once again tomorrow, with a west to east
gradient in smoke concentration in the afternoon. This is due to a
shift towards westerly surface flow. Eastern portions are likely to
stay in the smoke layer through peak heating, keeping temperatures
in the upper 70s to low 80s, whereas W/SW portions should quickly
rise into the mid to upper 80s as skies clear in a better mixed
environment.
&&
.Long Term...(Wednesday night through Tuesday)
Issued at 306 PM EDT Tue Jun 27 2023
The long term period will see daily chances for showers and
thunderstorms with warm to hot conditions throughout the period. For
the first few days of the period, central Indiana will sit on the
periphery of an upper level high that will be centered near the
ArkLaTex region. This will place us in a decent environment for MCS
development from Thursday through Friday with a warm and humid
airmass paired with an impressive mid to upper level jet and a CAPE
gradient across the forecast area.
While several uncertainties exist for the first part of the long
term with regards to when and where any systems could form, there is
a slightly higher confidence in the storms on Thursday potentially
becoming severe. A few parameters of concern include high dew points
in the 60s and even 70s with models showing CAPE getting into the
3000 to 4000 range. Shear also looks to be 40 to 50 kts with steeps
lapse rates of 7 to 8 degrees/km. Main threat will be for damaging
winds and large hail, but can`t rule out isolated tornadoes. Best
chances for storms to form would be in the afternoon hours, lasting
into the evening with best severe potential being across the western
half of the CWA. Some storms could be strong Friday and Saturday as
well but there is much less agreement on timing and location at this
time.
Temperatures will mostly be above normal through the long term with
highs in the 80s and 90s. The hottest days will be Thursday and
Friday as highs could get to the mid to upper 90s given the expected
strong southerly WAA. Will even have to watch for a heat advisory
potential as heat indices will get near the threshold.
Behind a cold front Saturday, temperatures will cool off slightly
for the start of the new week but will quickly rebound to near 90 by
the 4th. There will continue to be slight chances for precipitation
from Sunday, on as we will continue to sit under an active set up.
&&
.Aviation...(00Z TAF Issuance)
Issued at 613 PM EDT Tue Jun 27 2023
Impacts:
* MVFR to IFR visibility due to wildfire smoke and haze
Discussion:
Canadian wildfire smoke is reducing visibility to as low as 1 1/2
miles. Most locations will be in the 3-5 mile range but occasional
IFR visibility may be possible especially in the predawn hours.
Current indications are that vertical mixing after sunrise should
improve conditions though at least some visibility reduction will
continue through Wednesday. Winds will be light and variable for a
period tonight and then trend southerly.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...BRB
Short Term...Updike
Long Term...KH
Aviation...BRB
Area Forecast Discussion
National Weather Service Northern Indiana
656 PM EDT Tue Jun 27 2023
.SYNOPSIS...
Issued at 655 PM EDT Tue Jun 27 2023
Areas of haze and smoke continues tonight with lows into the
lower to mid 50s. Poor air quality continues into Wednesday. A
warmer pattern settles in Wednesday through this weekend, with
periodic chances for showers and storms near a frontal boundary
late Wednesday night through Saturday.
&&
.SHORT TERM...(This Afternoon through Wednesday)
Issued at 230 PM EDT Tue Jun 27 2023
A light shower or sprinkle remains possible into the late
afternoon across northwest OH given lingering moist/cyclonic flow
on the western flank of an exiting eastern Great Lakes upper
trough. Dry advection and deep subsidence is finally allowing for
some scattering of lower clouds in western zones, with
expectations for this clearing to reach northwest OH and south-
central MI tonight. This clearing and diminishing winds with low
level ridging building in should promote decent radiational
cooling later tonight. Patchy ground fog and relatively cool
morning lows in the low-mid 50s are the likely result.
Wildfire smoke and haze will also continue to plague the area
into at least tonight with relatively widespread visibility
restrictions likely persisting. Air Quality Alerts have been
extended into Saturday in IN and MI, though HRRR/RAP smoke plume
progs do suggest some improvement later tonight into tomorrow.
Wednesday will be a pleasant day otherwise with high pressure in
control. Some late day WAA should push highs in the low to mid
80s, with some increase in mid-high level clouds possible as
convective debris moves in from the Plains.
&&
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 230 PM EDT Tue Jun 27 2023
A "ring of fire" regime will setup across the region Wednesday
night through Friday night as a theta-e/instability gradient sets
up under increasingly perturbed west-northwest flow aloft. A
series of convective clusters will track along this boundary on
the north- northeast fringe of a lower MS Valley centered heat
dome/upper ridge. Confidence in this kind of a pattern coming to
fruition is high, however, confidence is very low on timing/track
of convective activity with mesoscale considerations playing a
large roll on how things play out each period.
Western portions of the area could get clipped by a convective
complex early Thursday morning, though better prospects for
redevelopment locally will come later Thursday afternoon into
Thursday night. Low level theta-a advection over a warm front
lifting into central/northern IL and western IN is expected by
this time, along with ~40 knots of deep layer shear, relatively
steep mid level lapse rates and moderate instability. This would
pose a threat for severe storms and heavy rain, though confidence
on where/when storms initiate and the timing of a mid level
impulse cresting the upper ridge remain low at this forecast
range.
The forecast to follow into Friday and Friday evening will be
dependent on what happens Thursday night. If a MCS and associated
cold pool/outflow do materialize and move through Thursday night
then Friday would be quiet with the active frontal zone forced
south of the area. This is the more likely outcome, though
additional convection could become a reality if Thursday night
activity is limited with the moisture/instability axis stalled
overspread.
The "ring of fire" pattern does look to break down over the
weekend as a positively tilted upper trough tracks into the Great
Lakes. This feature and its attendant sfc trough could focus some
additional shower/storm activity on Saturday, especially if there
is adequate heating and moisture return. Seasonable temps and
mainly dry conditions are expected to follow Sunday into early
next week, with the main take away through the entire period being
a return to more typical mid summer heat and humidity.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 655 PM EDT Tue Jun 27 2023
IFR visibilities in smoke/haze to likely degrade to LIFR at times
near daybreak in smoke/fog. Strong concentration of wildfire
smoke to persist amid developing strong surface based inversion
overnight. As temperatures fall below crossover /56 degrees at
KSBN and 59 degrees at KFWA/ anticipate fine hygroscopic
particulates to promote fog development, especially given recent
moistened ground. LAMP and crossover guidance point to at least
occasional LIFR visibilities likely and have trended terminal
forecasts more pessimistic in this regard. HRRR smoke plumes shunt
highest Vertically Integrated Smoke south of terminals by
mid/late morning, but still anticipate MVFR visibility
restrictions in haze with persistent subsidence inversion based
near 3kft AGL to prevent thorough mixout.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Beach Hazards Statement until 1 AM CDT Wednesday for INZ103.
MI...Beach Hazards Statement until 2 AM EDT Wednesday for MIZ177-277.
OH...NONE.
LM...Small Craft Advisory until 2 AM EDT Wednesday for LMZ043-046.
&&
$$
SYNOPSIS...Murphy
SHORT TERM...Steinwedel
LONG TERM...Steinwedel
AVIATION...Murphy
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AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1113 PM EDT Tue Jun 27 2023
.UPDATE...
Issued at 1113 PM EDT TUE JUN 27 2023
Quick update to the forecast to eliminate mention of evening
thunder and bring grids into line with latest observations.
Thicker wildfire smoke with notable visibility restrictions -- as
low as 1.75 mile visibilities being reported at KLUK on the east
side of Cincinnati, though most locations are reporting 2 to 4
mile visibilities -- continues to work southward into Kentucky.
Dense valley fog remains a concern later in the night, especially
where skies remain relatively clear.
UPDATE Issued at 812 PM EDT TUE JUN 27 2023
Upstream observations show a broad area of Canadian wildfire
smoke reducing visibilities to between 1 and 3 miles from Southern
Ohio/Indiana northward into Michigan and Wisconsin. As per HRRR
guidance, expect haze and areas of near-surface smoke to envelop
eastern Kentucky this evening and overnight. This will lead to
reduced visibilities and potentially unhealthy air quality.
Abundant smoke particulates (excellent condensation nuclei),
lingering low-level moisture, and clearing skies will favor rapid
fog formation in valleys later this evening. There is potential
for widespread dense fog -- something we will continue to monitor
for possible headlines later this evening. Dense fog and areas of
smoke wording was added to the overnight forecast with this
update.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 328 PM EDT TUE JUN 27 2023
There has been plenty of cu across Eastern Kentucky so far this
afternoon, with showers bubbling up mainly along and north of the
Mountain Parkway. Temperatures have generally underperformed thus
far, with most sitting in the mid to upper 70s as of 19z. This is
likely do to the cloud cover and some haze we have seen through
early this afternoon, but still another couple of hours to squeak
out a few degrees more.
The short term period will generally feature improving weather
conditions, aside from haze, tonight into Wednesday, where the
midweek will fair mostly dry and seasonable. Starting first aloft,
troughing entangles much of New England to the Mid Atlantic, where
broad ridging sits across Central Texas. This will keep Eastern
Kentucky under the influence of NW flow in the mid levels, resulting
in the rippling of impulses through the flow and the associated
convection we have seen so far this afternoon. As we work overnight
and lose daytime heating, this activity will wane and rising heights
will give way to mostly dry conditions into Wednesday through
Wednesday night. At the surface, high pressure will meander east out
of the Ozarks, ending up along the Central Appalachians by periods
end. An upper level disturbance will meander east along the
periphery of the ridge out of the Plains late in the period, where
CAMs indicate a possible decaying MCS of sorts could sink out of the
Midwest into the start of the extended.
Temperatures will vary through the short term, with dependency on
how much/dense stratus build down versus fog develops tonight. With
high pressure passing overhead, low level moisture will allow for
such development, which could inhibit large ridge/valley splits.
Into Wednesday, skies will gradually clear out through the day but
hazy conditions are expected to persist per RAP and HRRR guidance
from Canadian wildfire smoke. An uptick in highs, compared to today,
will be noted, with most locations in the low to mid 80s. Patchy
river valley fog with lows ranging in the mid 50s to low 60s then
follows Wednesday night.
.LONG TERM...(Thursday through Tuesday)
Issued at 407 PM EDT TUE JUN 27 2023
Key Messages:
-We will see hot and humid conditions through the end of the
week.
-Rain chances will be possible each day and increase into early
next week.
-Some rainfall could be heavy at times, moving toward
the weekend.
On Thursday, a summer pattern will be in place across eastern
Kentucky as strong ridging sets up in the Lower Mississippi River
Valley, with an ensemble system showing 594 decimeters high. In
the Ohio Valley, we will remain on the perimeter of this ridging,
and this will remain more in the ring of fire region, so to speak.
Leading to daily afternoon chances of showers and thunderstorms.
The other issue that could be problematic is that this setup would
support MCS activity, and we see this in several of the
deterministic model outputs showing mid-level waves riding the
ridge. This leaves a fair amount of uncertainty when it comes to
how this all plays out given that these kinds of features are
typically more mesoscale-driven, but the pattern certainly
supports this kind of activity. After this, the ensemble systems
support this ridging, pushing east and staying to our southeast as
a trough pushes toward the Midwest. This will bring a cold front
toward the area, giving way to cooler temperatures but increased
chances of showers and thunderstorms each day, Sunday through
Tuesday.
Thursday through Saturday...
The ridge-riding MCS potential will be interesting within this
period given the ample moisture and instability that will be
present. This will definitely play a role in afternoon highs and
seeing some higher numbers than expected based on the pattern.
Looking at the ensemble systems, the GEFS seems to be driving the
afternoon highs up. Given the potential clouds and convections,
they did opt to lower afternoon highs toward the fiftieth
percentile of the NBM, and the NBM run this morning did trend
cooler. Overall predictability is quite tough on the potential for
MCS, but some of the deterministic and ensemble models do show
this possibility. The first round could be Thursday night, but
nailing a location down at this point is quite difficult. On
Friday, there was some indication of severe potential in the ECMWF
EFI (strong CAPE and Shear signals), but uncertainty in cloud
cover and mid-level waves left a lot of questions on convective
evolution.
Sunday through Tuesday...
The mid-level trough carries the ridging, bringing in a cold
front and better chances of showers and thunderstorms. Given this,
PoPs are higher (in the 60–70 percent range at times) in this
part of the period and will favor the afternoon and evening
periods. The overall afternoon highs will be near normal, in the
low to mid 80s. Ample moisture will be in place, and therefore
some heavier rain could be possible, especially if the boundary
stalls nearby.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 812 PM EDT TUE JUN 27 2023
VFR conditions were noted at all sites at the start of the TAF
period. Satellite imagery shows an area of thick haze and smoke
upstream from northern Kentucky to Wisconsin, pushing southeast.
This will likely result in visibilities dropping to at least MVFR
at all locations overnight. The smoke particulates should also
lead to enhanced fog formation, potentially dropping visibilities
to LIFR/VLIFR at most locations late in the night. Visibilities
should improve after sunrise Wednesday as the fog burns off; but,
the smoky haze will linger, likely keeping visibilities low-end
VFR for much of the day. Winds will remain variable at 5 knots or
less through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEERTSON
SHORT TERM...BB
LONG TERM...DJ
AVIATION...GEERTSON
Area Forecast Discussion
National Weather Service Morristown TN
924 PM EDT Tue Jun 27 2023
...New UPDATE...
.UPDATE...
Issued at 921 PM EDT Tue Jun 27 2023
Radar shows the isolated showers across the north have ended, so
will remove the remaining low evening PoPs with this update.
Overall the forecast looks reasonable, so only other changes will
be to tweak temps and dew points.
&&
.SHORT TERM...
(This evening through Wednesday)
Issued at 257 PM EDT Tue Jun 27 2023
Key Messages:
1. A few isolated to scattered showers expected across the north
this afternoon/evening.
2. Dry Wednesday with a slight warming trend. Hazy skies possible.
Discussion:
Recent satellite trends show low scattered cu blanketing the
forecast area this afternoon as a few light returns have started to
develop on radar across portions of NE TN and SW VA. The potential
to have some isolated to scattered showers will continue across the
northeastern areas into the evening as lobes of vorticity translate
through mean flow aloft. However, ridging across the central CONUS
continues to nudge eastward. This has resulted in increasing
subsidence aloft and is depicted in model derived soundings with a
relatively deep cap present from roughly 725mb to 600mb. This cap
will reduce available energy and will inhibit the chances for
lightning with any activity this afternoon. Given this, have limited
wording to slight chance thunder. This cap is noticeably stronger in
vicinity of TYS and CHA areas and is why PoP chances were limited to
the Morristown area and eastward.
Models suggest some low clouds/fog developing, mainly across
northeastern areas, tonight but a little less certain with the
impacts given the relatively drier air mass. This will partially
depend on the coverage of showers this afternoon. Wednesday will be
dry as ridging presence increases and brings about the start of a
warming trend. Additionally, with continued nwly flow aloft these
past few days, HRRR products suggest a return of some hazy skies due
to the intrusion of smoke from Canadian wildfires. Have included
haze in the ZFP wording.
&&
.LONG TERM...
(Wednesday night through next Tuesday)
Issued at 257 PM EDT Tue Jun 27 2023
Key Messages:
1. Mostly dry Wed night and isolated activity Thurs, then rain
chances increase for the late week and weekend.
2. High temperatures in the upper 80s and 90s are possible Thursday
through Saturday.
3. Heat indices could climb well into the 100s in the southern
Valley Friday/Saturday.
Discussion:
The big hot Texas ridge you`ve been hearing about in the news is
coming this way, and by the latter portion of the week it will send
our temperatures upward into the 90s across most of the Valley.
Combined with dewpoints in the 70s, heat indices over chunks of the
area will climb above 100 Friday/Saturday, but worse on Friday.
Models are disagreeing a little on temps but moreso on dewpoints.
Heat Advisories or even Excessive Heat warnings may be needed.
Northwest flow thunderstorm complexes are possible late in the work
week, but over the weekend the upper pattern becomes more
southwesterly as a trough moves toward us from the central plains.
Thus a tap of humid flow will make diurnal/convective rain chances
look pretty solid from Sunday through Tuesday.
Heat and humidity will aid convective buoyancy Friday and Saturday,
so we will have to keep an eye open for hail and wind threats.
&&
.AVIATION...
(00Z TAFS)
Issued at 719 PM EDT Tue Jun 27 2023
May be a stray shower around TRI early in the period but
probability looks too low to include in the forecast. Main
aviation weather concern is possible fog or lower cigs late
tonight at TRI, but it looks more likely to remain VFR there so
will just keep the previous 6SM BR mention in the forecast for
now. Will go with a VFR forecast for the period all sites.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 66 92 70 96 / 0 10 10 20
Knoxville McGhee Tyson Airport, TN 64 88 66 93 / 0 10 10 20
Oak Ridge, TN 64 88 66 92 / 0 10 10 20
Tri Cities Airport, TN 61 83 60 88 / 20 0 10 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...KRS
LONG TERM....13
AVIATION...
Area Forecast Discussion
National Weather Service Spokane WA
351 PM PDT Tue Jun 27 2023
.SYNOPSIS...
Scattered showers and thunderstorms will continue this afternoon,
then gradually decrease after dark, before developing again
Wednesday afternoon. Some of the thunderstorms will produce
locally heavy rain, hail, and frequent lightning. High pressure,
with drier air, builds over the Pacific Northwest Thursday into
early next week. This will lead to little to no potential for
precipitation. Highs are forecast to rise into the upper 80s to
mid 90s over the weekend into the July Fourth holiday.
&&
.DISCUSSION...
This evening through Friday: Storms continue to form across the
region today. Storms have formed over the higher terrain in the
Idaho Panhandle and eastern Washington, as easterly flow is
forced up the mountainous regions by the upper-level low still
positioned near the Washington-Oregon border. There is
considerable solar heating that can initiate vertical motion
across the area that`s reinforced by the upper level divergence
from the low. Guidance has storms continuing to develop through
the early afternoon, but there is little vertical wind shear
(0-6km is near 14 knots) so most storms will be short-lived and
most will die off as quick as they form, though some stronger
storms cannot be ruled out. Forecasted soundings show an
enhanced-v signature, which indicates that dry microbursts and
very gusty winds are possible today where storms are able to grow.
This will likely be a larger threat over the higher terrain in
the Idaho Panhandle. Later this evening the HRRR and other CAMs
models depict a vorticity maxima (created by the upper-level low)
moving across the area, along with an MCS from convection last
night over Montana and Wyoming. These two features will make
organized convection possible for a short window between 6pm-10pm
if it realized. Confidence that this will take place is low
(20-30% chance). The organized convection would be able to move
across eastern Washington and bring with it heavy rains, gusty
winds and frequent lightning. The freezing layer is forecasted to
be around 3 kilometers and CAPE levels between -20 and -30C are
low, so large hail is unlikely. Convection potential should taper
off as the sun sets near 9 pm.
Tomorrow, convection is possible in the higher terrains again, but
should be much weaker than today as the low ejects to the east and
there is less forcing over the area. ECMWF ensemble guidance is
signaling PWAT values 130-140% of normal tomorrow, so brief
downpours will be possible with the storms that do form. The NBM
gives a 40% chance for rain in southeastern Washington and the
lower Idaho Panhandle. Thursday is more of the same with
thunderstorm chances over the mountains in the afternoon, though
chances stay low near 20% with the loss of the low’s forcing. The
HREF one hour QPF shows the probability of rain rates >1 inch/hr
is zero so the likelihood for prolonged heavy rain and flooding is
minimal. High temperatures will be in the upper 90s in the
valleys and 70s in the mountains with relative humidity values
near 40%. /Butler /Sinowitz
Friday to Tuesday: The pattern looks much calmer; temperatures
will be warm to hot each afternoon from Thursday to Tuesday, with
highs in the upper 80s in the valleys and low 70s in the higher
terrain. Some areas could reach into the lower to middle 90s. The
ECMWF ensemble gives the deeper Columbia Basin and L-C Valley
90-100% probability of exceeding 90 degrees Friday through
Tuesday; the GEFS holds off slightly, with probabilities near
80%. So what is causing the warming? Low pressure ejects to our
east Thursday night to be replaced by a strong ridge. The ridge
and its associated high pressure system over the Desert Southwest
will stop any significant moisture advection into the region,
keeping the area dry over the extended period. The GEFS and
European ensembles have PWATs between 40-60% of normal, much less
than our current situation. Overall the MSLP gradients are pretty
low area wide with the ridge, so winds will not be terribly high
but will still be in the low-grade breezy category with speeds
around 10-15 mph in the afternoon hours from Saturday onward, with
higher gusts. The higher speeds are more likely toward the Cascade
gaps and the western basin. The hotter temperatures and low RH
values during this period (around 15-25%) will help finer fuels
(like grasses) to dry out. This may be of concern for the fire
weather community going into the 4th of July holiday, but
confidence that critical thresholds will be met is low. /Solveig
/Sinowitz
&&
.AVIATION...
00Z TAFs: Cells over the high terrain of north Idaho and
northeast Washington will have a 40 percent chance of spreading
into Coeur d`Alene, Spokane, and Lewiston before 4Z. Localized
wind gusts to 35 mph, hail, and heavy rain cores will accompany
the strongest cells before convection weakens between 02-04z.
Winds will be light with VFR conditions after 4Z. /Butler
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 57 85 58 89 61 91 / 20 10 10 0 0 0
Coeur d`Alene 56 83 57 87 61 90 / 30 20 10 0 0 0
Pullman 54 80 55 85 58 89 / 40 20 0 0 0 0
Lewiston 63 88 63 93 66 98 / 50 30 0 0 0 0
Colville 51 84 53 88 57 90 / 20 30 10 10 0 0
Sandpoint 56 83 56 87 59 88 / 30 30 20 10 10 0
Kellogg 57 77 59 82 63 86 / 40 50 20 10 0 0
Moses Lake 58 91 59 93 60 96 / 10 10 0 0 0 0
Wenatchee 64 90 64 92 64 94 / 10 10 0 0 0 0
Omak 59 89 61 92 62 95 / 20 20 10 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Flood Watch until 9 PM PDT this evening for Central Chelan
County-Okanogan Highlands-Okanogan Valley-Upper Columbia
Basin-Wenatchee Area-Western Chelan County-Western Okanogan
County.
&&
$$
Area Forecast Discussion
National Weather Service Paducah KY
230 PM CDT Tue Jun 27 2023
.SHORT TERM...(Tonight through Wednesday night)
Issued at 230 PM CDT Tue Jun 27 2023
Northwesterly flow of relatively cool and dry air continues
through this evening. Diurnal cumulus clouds will dissipate by
sunset. An area of smoke from Canadian wildfires on visible
satellite imagery is moving south to the I-64 corridor this
afternoon. Vsbys are 2 to 5 miles in the smoke. The vertically
integrated smoke product from the hrrr brings this smoke down
across the lower Ohio Valley this evening. The forecast will
mention smoke or haze tonight and Wed morning for many areas from
kpah north and east. Air quality alerts have been issued for sw
Indiana and southern Illinois by state environmental management
agencies.
Late tonight, southwest 850 mb flow behind the departing high
will advect a strong low level theta-e gradient into southeast
Missouri. Short term cam models are consistent in developing a
thunderstorm complex immediately behind this 850 mb gradient. The
complex is forecast to weaken as it moves into se Missouri and
possibly sw Illinois early Wed morning. The elevated convection
will outrun the unstable air, but the remnants could still produce
some measurable rain in far west KY and southern IL Wed morning.
The afternoon should be mainly dry. Increasing southerly flow and
strong solar heating will help raise temps into the lower 90s,
despite the mostly cloudy start to the day.
Another complex of showers or thunderstorms may develop late Wed
night along the 850 mb theta-e gradient. This activity would be
mainly over sw Indiana and the Pennyrile region of west KY. There
is little model support from the cams, but a slight chance pop
will be maintained in those areas.
.LONG TERM...(Thursday through Tuesday)
Issued at 228 PM CDT Tue Jun 27 2023
The main concern is excessive heat potential for Thursday and
Friday.
The heat dome over the Deep South and Texas will make a temporary
push northward, roughly coincident with the expansion of the
strong 500 mb high. The models continue to show impressively high
850 mb temps at or above 25C pushing east into the lower Ohio
Valley by Friday. The ensemble situational awareness tables still
indicate these values are at or above the 99th percentile in the
model climate period (30 years). This should correlate with some
hot surface temps exceeding 100 degrees in some areas.
The Excessive Heat Watch will remain in effect for se Missouri
and parts of srn Illinois and west Kentucky Thu-Fri. There are
still variations in model dew points. The 12z nam remained among
the highest dew point guidance, with 2-meter dew points near 80 in
western KY at times. The forecast will lean toward a model
consensus in the mid 70s. Even using the lower consensus guidance,
peak heat indices are expected to peak around 110 (warning
criteria) on both days.
The possibility of convection still exists Thursday through
Friday, mainly on the northern and eastern periphery of the strong
500 mb high. Small pops will be maintained in an area roughly
north and east of the watch area. GFS model soundings continue to
show a strong capping inversion / elevated mixed layer both days.
Even at kevv, convective inhibition remains over 100 both days per
gfs soundings viewed in Bufkit.
Convective inhibition decreases significantly on Saturday, when a
500 mb shortwave trough will move eastward from the Plains. This
fairly weak, strongly tilted trough will act on a very moist and
unstable air mass. Thunderstorm potential will be considerably
higher on Saturday and Saturday night, when a weak surface
boundary will arrive. Some locally heavy rain would be beneficial
for parts of our area. Temps will remain hot outside of
convection, where highs will be in the mid to upper 90s. It is
possible heat headlines could be extended into Saturday.
The remnants of the frontal boundary will stall or dissipate over
our region Sunday. Highs Sunday will decrease into the upper 80s
and lower 90s as dew points edge downward. Some diurnal convection
could again develop near the remnants of the front, but weaker
forcing should keep coverage isolated to scattered.
Early next week, a rather flat upper-level flow will encompass
most of the nation. Our region will be on the southern edge of the
band of mid-level westerlies. Lingering heat and humidity could
promote some diurnal convection both Monday and the Fourth of
July. Highs will generally be in the lower 90s, with heat indices
peaking in the mid to upper 90s.
&&
.AVIATION...
Issued at 1228 PM CDT Tue Jun 27 2023
Scattered diurnal cumulus clouds have formed at all sites, and some
broken cumulus coverage exists from kevv eastward. Cloud bases will
rise to over 5k feet agl by mid afternoon. The cu will dissipate
around sunset, followed by some increasing mid and high cloudiness
late tonight.
A weakening area of showers and thunderstorms will graze southeast
Missouri, sw Illinois, and sw Kentucky Wed morning, but the
potential for mvfr conditions is too low to mention in the tafs.
Winds will be northwest 5 to 12 kt this afternoon, then light
tonight.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Excessive Heat Watch from Thursday morning through Friday
evening for ILZ080-081-084-085-088>090-092>094.
MO...Excessive Heat Watch from Thursday morning through Friday
evening for MOZ076-086-087-100-107>112-114.
IN...None.
KY...Excessive Heat Watch from Thursday morning through Friday
evening for KYZ001>013-016-017-022.
&&
$$
SHORT TERM...MY
LONG TERM...MY
AVIATION...MY
Area Forecast Discussion
National Weather Service Pittsburgh PA
940 PM EDT Tue Jun 27 2023
.SYNOPSIS...
Scattered showers will end tonight as low pressure exits the
region. Dry weather will return Wednesday and Thursday under
high pressure.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Scattered showers will end overnight as the persistent low that
has over the Great Lakes region opens into a trough, and exits
the area. Light fog and haze should persist overnight, with low
level moisture in place, and as smoke particles from the
Canadian wildfires increase overnight in north-northwest flow.
Building surface high pressure could result in some reduction of
stratocu across Ohio late tonight, though mostly cloudy skies
are expected to persist across the rest of the area with the low
level moisture in place.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
Dry weather returns Wednesday under increasing subsidence as ridging
builds in from the west. With light winds and limited cloud
coverage fog looks likely overnight Wednesday into Thursday
morning. Dry weather and seasonable temperatures continue
Thursday as high pressure transitions across the region.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Mid-level flow goes zonal by Friday, while a more southerly
low-level component brings increased moisture back to the Upper
Ohio Valley. Diurnally-driven activity appears possible. This
will likely also be the warmest day of the period. Ensemble/NBM
probabilities show that 90 degree potential is low, but readings
in the mid and upper 80s are likely.
After that, lift could be supplied by the possible
approach/passage of a warm front Saturday, followed by a mid-
level shortwave trough and a cold front on Sunday, leading to an
active weather weekend. More scattered activity could then
linger into Monday depending on how quickly the upper trough
departs. Temperatures next weekend into early next week will be
seasonable.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
A low pressure system spinning to our north will continue to
hold widespread MVFR to IFR conditions overnight into early
tomorrow morning due to sufficient sfc moisture and cold
advection under NW flow. Prolong IFR cigs appear promising for
DUJ/FKL through 13Z. Elsewhere, IFR conditions may develop just
before dawn before returning to MVFR with sfc heating.
Haze/smoke from wildfire activity in Canada will likely impact a
number of terminals just before dawn based off the HRRR near-
surface smoke model. Dense hazy and/or smoke has been noted
already near Lake Erie. TEMPO lines were added for the potential
of the passage of thick smoke/haze after 07Z; timing was
determined using the HRRR smoke model. After 13Z, haze will
linger but models have noted denser particles drifting further
south or linger to our west; adjust vis between 6SM to 5SM. VFR
cigs will likely develop after 18Z as high pressure builds to
our west and drier conditions prevail.
.OUTLOOK...
Radiational fog is possible Thursday morning if sufficient
clearing develops. Otherwise, VFR conditions are likely after
dawn through the evening.
The next chance of general restrictions arrives late
Friday/Saturday with a low pressure system.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...WM
NEAR TERM...WM
SHORT TERM...88
LONG TERM...88
AVIATION...Hefferan
Area Forecast Discussion
National Weather Service Tucson AZ
254 PM MST Tue Jun 27 2023
.SYNOPSIS...Above average heat will continue through the weekend.
A modest moisture increase will bring a chance of thunderstorms
mainly near the international border and far southeast Arizona
this week. Winds will be breezy each afternoon as well.
&&
.DISCUSSION...A temporary respite from the excessive heat after
today as high pressure shifts east of our area and afternoon highs
fall back a few degrees. High pressure will build through much of
the west next weekend and could bring another round of heat
headlines (this time oriented such that strongest heat will be
west and northwest of our area).
Meanwhile, we`ve been monitoring a moisture increase from Sinaloa
and the Gulf of CA into central and northern Sonora over the past
couple of days. A broad but shallow moisture increase is expected
across much of our area, but convective outflows will likely be
the best predictor for storm coverage north of the international
border. Storms forming south and southeast of the border this
afternoon will probably end up pushing outflows north and
northwest this evening that will prime Cochise County with better
convective potential Wednesday afternoon and evening. The HRRR
then pushes further west and north with outflows tomorrow evening
before drier westerlies push in under a trough north of our area
later in the week. Lightning and strong gusty outflows the main
concern Wednesday afternoon, with narrow rain shafts and limited
measurable rain chances.
As previously discussed, the Eastern Pacific tropics are now quite
active. Our first named storm of the season Adrian has formed
well off the southwest Mexican coast around 15.3N 106.0W and is
expected to drift slowly westward. Another wave near the coasts of
Guatemala and El Salvador is expected to develop into a tropical
cyclone as well, and could end up tracking a little further north
with the high shifting out of a blocking position. That`s the one
that could give a big boost to establishing broader foundational
support for the monsoon into central and north central Mexico to
start July. We`ll see if we can get a push into our area for our
typical 4th of July ramp-up in coverage, but heat still looks
like the biggest story for now.
&&
.AVIATION...valid through 29/00Z.
Mostly clear at KTUS and KOLS. KDUG will see SCT-BKN clouds AOA
12k ft AGL. Isold -TSRA/-SHRA near KDUG late this afternoon and
evening. Storm coverage increasing Wednesday, but still mainly
east of KTUS and KOLS. Sfc winds west to southwest 10-15 kts with
gusts up to 25 kts until 28/03Z, diminishing overnight before
increasing again after 28/18Z. Gusty erratic outflows possible
from storms near and south of the border. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...High temperatures will be above average through
the weekend, with the hottest day expected to be today and
perhaps Sunday (around 6-10 degrees above normal). Min RH values
will be in the 4-10 percent range in the lower elevations and
between 10-18 percent in the mountains through much of the week.
An exception to this for areas east and southeast of Tucson
Wednesday and Thursday where minimum RH values may climb into the
20 percent range with outflows from thunderstorms temporarily
pushing deeper moisture up from Sonora. Isolated thunderstorms
possible Wednesday afternoon and evening through 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. Stronger winds at 15-25 mph and gusts up to
40 mph are expected across northern Graham/Greenlee counties
today. Because of this a Red Flag Warning is in effect until 8 pm
MST for northern portions of Fire Weather Zone 152 and all of
Fire Weather Zone 153.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 8 PM MST this evening for AZZ503-
504-506>509.
Red Flag Warning until 8 PM MST this evening for AZZ152-153.
&&
$$
Meyer
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