Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/06/23
Area Forecast Discussion
National Weather Service La Crosse WI
1022 PM CDT Wed Jul 5 2023
.DISCUSSION...(This evening through Wednesday)
Issued at 211 PM CDT Wed Jul 5 2023
Key Messages:
- A very comfortable upcoming week with low humidity and near
normal July temperatures. Rain chances are low and no
significant weather is expected.
Overview:
Isolated to scattered thunderstorms developed last evening, becoming
more numerous after 03Z and continuing in a southwest to northeast
band...shifting south through parts of the forecast area. By 14Z
this morning, the more organized showers and a few storms had pushed
east our of Juneau and Adams counties with a few lingering showers
and sprinkles across the forecast area. Rainfall where the showers
and storms set up were generally .10" to .50" with pockets of .50 to
1.25". Here at the NWS La Crosse office, we had 0.96" between the
downpour Tuesday afternoon and the showers today. That gives us a
total of 2.30" for the two days. The La Crosse airport had 0.63" of
rainfall since yesterday and the Rochester airport only a trace. By
15Z, the winds had shifted to the north at Platteville and Dubuque,
however dewpoints were still in the 70s. Farther north toward
Rochester, dewpoints had lowered to around 60. By 19Z...the line of
convection with the surface front was taking off with several
warnings already issued.
Water vapor satellite imagery, heights and lightning showed the
broad trough from Ontario through the Upper Mississippi Valley, the
Northern Plains, and the Northern Rockies. Shortwave troughs were
moving through the eastern portion of the trough with some lightning
associated with the waves over Ontario, and Kansas, and deeper
moisture noted locally over parts of WI and northeast Iowa.
Cooler and drier weather through Thursday:
The 500mb trough will continue to swing through tonight and Thursday
with drying at all levels. Until the trough scours the deeper
moisture out of the area, a few showers and storms can occur. By
late this afternoon, the 21Z RAP forecast has the axis of
instability over parts of the GRB/MKX/LOT/DVN forecast area from
2000-3500 J/kg. The gradient is forecast to be across southeast
Wisconsin and northeast Iowa. The hi-resolution models show the
perkier storms to be east of the forecast area but will need to
metwatch for any activity on this gradient. As of 19Z...we have a
few showers that have increased and will continue to monitor the far
south, however most indications are the stronger storms will remain
is of the area.
With the trough still moving through and residual moisture,
cumulus have increased. These clouds should gradually give way to
clearing skies with the loss of heating. Drier surface dewpoints
will continue to overspread the area through Thursday with
dewpoints falling through the 60s, the 50s, into the 40s Thursday.
With the heating Thursday and moisture in the low levels, we are
looking at our convective temperatures being met in the upper 60s
with cumulus around. The HRRR hints at a few sprinkles possible
for parts of central WI Thursday, but will not mention in the
forecast for now.
Below normal temperatures are forecast. Lows tonight should drop
into the 40s and 50s. Highs Thursday should mostly be in the 70s.
Thursday Night through Sunday...Large scale troughing will
dominate central Canada through the period with the northern
states to Great Lakes under the southern influence of that trough.
There is a somewhat confluent flow between the northern stream
and more zonal branch coming across the Rockies. This will mean
near normal temperatures and lower humidity /dewpoints 55-60F/. On
Friday, a shortwave trough emanating from the Rockies will
traverse the area with increases in mid-level moisture, but dry
low-levels in the ensemble consensus will limit rain chances to
sprinkles or very light rain chances. Will have to monitor this
system for a possible rain chance increase late Friday and Friday
night. There are outliers such as the 05.12Z NAM that goes bonkers
with cyclogenesis and rainfall in the region...for now that seems
very aggressive with convective feedback in the intensive
deformation zone and low center. Overall, after Friday, it should
be mostly sunny with very small rain chances Sunday and Sunday
night.
Monday through Wednesday...While the large scale flow regime remains
generally the same, spread in the model forecasts increase in this
period. Most of the model spread in the ensembles is in the timing
and southern extent of the deepening Canadian trough. But, there is
a dominant cluster (51 of 100 members) within the Grand Ensemble
(ECMWF/GEFS/ CanadianEns) that suggests this strong push of cooler
air and forcing will affect the area Tuesday into Wednesday driving
increased rain chances and below normal temperatures again. Somewhat
surprising is the similarity in the deterministic 05.00Z and 12Z
ECMWF and 12Z GFS for early next week suggesting a warmer Monday
followed by strong frontogenetic forcing, some 850 mb moisture
transport into the front, and widespread rain Tuesday afternoon
and night. Many days to iron out these details.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1021 PM CDT Wed Jul 5 2023
VFR conditions are forecast through the TAF period. Upstream on
Wednesday afternoon a thick deck of cumulus clouds developed, and
we expect the same to occur over our forecast area Thursday
afternoon. This could lead to patchy sprinkles and scattered to
broken cloud decks. Winds remain northwesterly at 5-10 knots.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Zapotocny/Baumgardt
AVIATION...KAA
Area Forecast Discussion
National Weather Service Denver/Boulder CO
949 PM MDT Wed Jul 5 2023
.UPDATE...
Issued at 937 PM MDT Wed Jul 5 2023
It`s a mix of showers and storms, low clouds, and fog across the
forecast area... which is *not quite* exactly what one would
expect on an early July evening.
A few updates to the forecast this evening. We`ve added much more
fog into the grids. GOES Nighttime Microphysics satellite shows a
broad area of fog/mist/low cloud cover across the plains and lower
foothills. We`ve also seen multiple mPing reports of dense fog,
along with some briefly reduced visibility from automated
stations. Recent trends in the HRRR suggest that this should
gradually become more widespread tonight. Have gone ahead with a
broad Dense Fog Advisory... with the densest fog most likely
settling across Larimer and northern Weld counties.
Otherwise, have made some minor adjustments to most of the
foundational grids to better reflect current conditions.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 236 PM MDT Wed Jul 5 2023
Low clouds to persist through tonight across much of the Front
Range and eastern plains. This will keep the airmass cool and
stable. The first few storms that formed over the higher terrain
and then moved east over the cooler stable air have fizzled. Over
the mountains and mountain valleys, it has been sunny most of the
day and the airmass has destabilized. Here surface based CAPE is
300-800 J/kg. Some strong storms will be possible through the
evening. There is a sweet spot for strong/severe storms. It runs
from Park county eastward across the Palmer Divide...and possibly
into Lincoln county of it can heat up a little more. There is also
a little clearing north of the Palmer Divide. This area could
also see a few storms as well with convergence along the Denver
Cyclone helping to trigger storms.
For Thursday, strong west-northwest flow aloft will prevail. Most
of the area will be under the left extra region of the jet, which
may help thunderstorms develop. Skies slowly clear Thursday
morning and early afternoon. This will allow temperatures to climb
into the mid 70s to lower 80s. The airmass will remain moist with
dew points in the 50s to lower 60s. These temperatures and dew
points yield surface based CAPEs of 1300-2500 J/kg. Bulk shear
0-6(km) during the afternoon will be 50-60 knots. These parameters
are good for supercell thunderstorms with large hail and damaging
winds possible. Models also showing a fair amount of CIN and cap,
with spotty convection forming during the afternoon. If and where
the cap is broke, storms should be able to become strong to
severe quickly.
.LONG TERM...(Thursday night through Wednesday)
Issued at 236 PM MDT Wed Jul 5 2023
Unstable conditions will linger through Thursday evening in the
plains, under continued moist southeasterly flow and with some
dynamic support in the form of upper level diffluence and
divergence below the front left quadrant of the jet streak. CAMs
continue to show largely discrete convective cells drifting ESE
over rural Adams/Arapahoe Counties and into Washington and Lincoln
Counties later in the evening ahead of a weak front, with a
favorable shear profile that would support large hail as the
primary threat and coinciding with SPC`s Enhanced Risk area.
Tornado potential will also exist with primary storm mode likely
supercellular in the plains. After another day of relatively
widespread precipitation, moist low- levels will persist overnight
and likely result in fairly extensive stratus into the early
morning hours Friday.
Weak troughing pushes east over the Central Plains Friday whilst
a jet streak moves directly overhead. Following a weak morning
surface front, prevailing flow aloft will become more
northwesterly. Clearing will be an important question Friday and
may inhibit convective initiation, particularly over the lower
elevations. The high country should clear more effectively in the
morning and allow for initial development of showers and
thunderstorms. Burn scar flash flood risk will remain moderate
Friday, with steering level flow mostly 10-20 kts, lower than
we`ve seen over the past few days. Thus, any heavier cells could
pose a concern, especially for the Cameron Peak burn scar. A few
strong storms will certainly be possible for the I-25 corridor and
plains, under a parameter space that will only be marginally less
impressive than Thursday. Highest potential for severe
thunderstorms looks focused over more rural areas east and
southeast of Denver. With ample cloud cover and in a post-frontal
environment, highs may struggle to hit 80 F for most of the lower
elevations, for another cooler-than-average day.
There is little in the way of any synoptic change on Saturday, as
we remain under broad northwest flow aloft with weak troughing to
our northeast and the slow-moving jet still over northeast
Colorado. In fact, moisture looks to bump back up with PWAT
anomalies 150-200% of normal for the lower elevations in the
afternoon as moist southeast surface flow returns. With lingering
instability, this should sustain a continued potential for
scattered showers and thunderstorms, a few of which may be strong.
As we head into the latter half of the weekend, the pattern
finally looks to flip a switch. There`s broad consensus in an
upper level ridge beginning its expansion over the Intermountain
West on Sunday, providing for a reduction in moisture and a more
stable air mass. With some moisture still in place, will maintain
isolated showers in the forecast, but severe weather will be
unlikely based on current guidance. Expect slight warming with
highs creeping back into the 80`s for the lower elevations.
The ridging and warming pattern then looks to accelerate into
early next week, with a more pronounced warming trend that should
see us climb to near or slightly above 90F in the urban corridor
by Tuesday or Wednesday. The lower elevations should remain dry,
with only isolated showers or weak thunderstorms possible over
the higher terrain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 540 PM MDT Wed Jul 5 2023
Widely scattered showers and a few TS will linger near the
terminals for the next couple of hours, though overall TS coverage
is expected to decrease. Main impacts from this has been lower
cigs and a few spurts of stronger, more variable winds.
Once the remaining showers exit the region, guidance is in good
agreement that widespread stratus will persist/redevelop this
evening. Some models hint at fog across the region, though at this
point it looks like that would stay north of the terminals. Still
would expect IFR/perhaps brief periods of LIFR into the morning
hours Thursday. Stratus should break up through the morning on
Thursday.
There is also a conditional threat of additional TSRA tomorrow
depending the evolution of stratus and daytime surface heating.
Guidance keeps the area fairly well capped, but a couple
strong/severe storms would be possible after 21z or so if capping
is weaker than projected.
&&
.HYDROLOGY...
Issued at 236 PM MDT Wed Jul 5 2023
Scattered thunderstorms over the higher terrain and Palmer Divide
will produce heavy rainfall this afternoon and evening. Storms
will be quick moving which will keep the flooding threat low.
Another round of scattered thunderstorms will occur Thursday,
this time through out the Front Range and eastern plains. The
strongest storms will produce heavy rainfall, but again the storms
will be quick moving, limiting the flash flood threat.
Scattered afternoon showers and thunderstorms are expected each
day through Saturday, under an unstable and moist air mass.
Steering level flow shouldn`t be too different Friday and
Saturday, but will likely be slower than we have seen during the
past couple of days. Thus, any stronger thunderstorms will bring
potential for flash flooding, particularly east of the Divide
(for the Cameron Peak burn scar).
Any training thunderstorms will carry the potential for flash
flooding for non burn scar areas as well, particularly considering
recent rains and soil saturation.
The pattern turns notably drier beginning Sunday, with reduced
precipitation chances. Nonetheless, at least a slight chance of
precipitation will continue for the high country each afternoon.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM MDT Thursday for COZ038>040-042-
043.
&&
$$
UPDATE...Hiris
SHORT TERM...Meier
LONG TERM...Rodriguez
AVIATION...Hiris
HYDROLOGY...Meier/Rodriguez
Area Forecast Discussion
National Weather Service State College PA
1122 PM EDT Wed Jul 5 2023
.SYNOPSIS...
Fairly typical/seasonal early July summertime heat and humidity
will make for a steamy second half of the week with an uptick
in thunderstorms expected through the weekend. Locally heavy
rain is possible with a risk of flooding/runoff concerns Friday
through Sunday.
&&
.NEAR TERM /THROUGH THURSDAY/...
A weak shortwave passing across the Virginias is sustaining a
few isolated showers late this evening south of the Mason Dixon
Line. Satellite loop at 02Z shows some lingering cumulus along
the southern tier of the state, where an isolated shower can`t
completely be ruled out until passage of shortwave around 06Z.
Otherwise, mostly clear skies and light wind under surface ridge
will promote patchy valley fog formation overnight, which could
become locally dense around daybreak Thursday. Dewpoint
depressions are already near zero across the Laurel Highlands,
where fog formation is imminent.
It will be a muggy night with lows several degrees above climo,
ranging from the lower 60s in the NW to around 70F in the lower
Susquehanna Valley.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
Another partly to mostly sunny, very warm and humid day is on
tap for Thursday, as surface ridge shifts east to the coastal
plain. We will remain in the same air mass as today, with
diurnal heating resulting in scattered afternoon convection.
Mean 0-6km shear <20kt should result in non severe, slow moving,
pulse type t-storms with brief heavy downpours in spots. Highs
should be very similar to today, ranging from 85-90F over most
of the region.
Scattered convection should fade with loss of heating over most
of Central PA to tonight. However, the approach of an upstream
trough and associated cold front will bring a renewed chance of
showers/tsra across the NW Mtns toward dawn Friday. Thursday
night will be another humid one with patchy fog and low temps
in the low 60s to low 70s.
Showers and t-storms will accompany a weak cold front across CPA
on Friday. CAPE/shear combination again does not favor severe
storms, but some heavy downpours remain likely especially with
pwats climbing >1.5 inches ahead of the front. Fcst highs drop
back by a few to several degrees given clouds and showers with
highs ranging from 75-80F over the Alleghenies to 85-90F in the
lower Susquehanna Valley. Some lower PW air arrives behind the
front and delivers a cooler night across the NW mtns with lows
falling back into the mid 50s. Patchy fog should also develop
again overnight into early Saturday morning.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
All medium range guidance stalls out the cold front east of the
forecast area Saturday. However, an approaching upper level
trough could support scattered PM convection. The focus by late
in the weekend turns to a developing surface low over the Ohio
Valley, which is progged by most guidance to track south of PA
Sunday into Sunday night. This scenario would likely result in a
cool, stratiform rain across much of the forecast area, with
warmer, more showery conditions possible over the southern tier
if the surface low tracks a bit further north than progged. Latest
ensemble plumes indicate most likely rainfall between 0.5 and 1
inch, with locally higher amounts possible from potential
convection over the southern counties.
Lingering showers appear possible Monday associated with passage
of the associated shortwave, then odds favor fair and
seasonable conditions Tuesday into at least part of next
Wednesday, as upper level ridging briefly builds over PA ahead
of an upper trough over the Grt Lks. Showers associated with
this feature and the associated cold front could arrive by
Wednesday PM.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
VFR conditions will prevail for the rest of the day except for
some very brief restrictions in any of the sct showers in the
area. Valley fog formation is likely tonight and MVFR
visibilities have been introduced in the TAF for all sites.
Confidence is not high in the formation of fog in the western
sites of JST and BFD due to a shallow moisture profiles, but
RAP analysis suggests some fog formation. Lower visibilities
have been included for the early morning hours. The fog will
dissipate quickly after sunrise and then VFR conditions are
expected through the end of the TAF period.
Outlook...
Thu...Mainly dry. Fog psbl in AM.
Thurs night-Fri...Showers and storms move in from the W.
Sat...Sct SHRA/TSRA, mainly S. Fog psbl in AM.
Sun...Nmrs SHRA/TSRA, esp S. Fog psbl in AM.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Steinbugl
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald/Steinbugl
LONG TERM...Fitzgerald
AVIATION...Colbert/Bowen
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
624 PM CDT Wed Jul 5 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Thursday night)
Issued at 245 PM CDT Wed Jul 5 2023
An upper level trough axis is pushing between the I-35 corridor and
the coastal plains. All satellite channels (Vis, IR and WV) are
detecting this feature as of 2 PM. Along and east of this axis,
isolated to scattered showers and thunderstorms are affecting parts
of the coastal plains with this trend continuing into the early
evening hours. Some of these storms could produce quick heavy
downpours with pwats values ranging from 2.1 to 2.3 inches based on
RAP and GFS model guidance. The seabreeze is forecast to keep
showers and storms going through late this afternoon into the early
evening as the boundary pushes into the I-35 corridor. With the loss
of daytime heating, expect activity to die down by sunset and coming
to an end around 9 PM or so. Today`s highs to reach the mid to upper
90s over most places with up to 101 degrees across few locations
along the Rio Grande.
For late this evening into Thursday morning, expect quiet weather
conditions for the most part with isolated to scattered showers
affecting the middle Texas coast. As the day progresses on Thursday,
increased moisture associated with an inverted trough over the
northwest Gulf of Mexico is forecast to push across the coastal
plains and the I-35 corridor, resulting in scattered showers and
thunderstorms. With pwat values in the 2.1 to 2.4 inch range, expect
heavy downpours with stronger storms. This activity is expected to
arrive mid to late afternoon to the I-35 corridor. Thursday`s high
temperatures are forecast to reach the upper 80s to low 90s across
the Hill Country and the I-35 corridor and up to 95 degrees along
the Rio Grande. Heat index values will be once again elevated but
not reaching heat headlines criteria.
Showers and storms start to dissipate into mid evening with dry
conditions then expected from overnight into early Friday morning.
&&
.LONG TERM...
(Friday through Wednesday)
Issued at 245 PM CDT Wed Jul 5 2023
A weak mid-level shear axis located just off the Middle Texas coast
entering Friday should gradually slide eastward and weaken as we go
through the day as stronger 500 mb heights build in from the west
with ridging centered over West Texas. Enough lingering morning
clouds and low-level moisture, looks to keep the afternoon highs on
Friday in the low 90s across the Hill Country and into the mid to
upper 90s elsewhere. While elevated, expect for the peak afternoon
heat indices look to stay shy of local Heat Advisory criteria. Rain
chances lower for Friday but enough moisture does remain to where
some isolated to perhaps widely scattered activity develops across
the coastal plains with the seabreeze. Elsewhere, the forecast will
trend mainly rain free.
As reiterated over the last several forecast packages, the heat is
to become the main headline during this weekend into next week. The
center of the 500 mb ridge will remain to the west, and could even
retrograde westward a bit through the long term. However, the ridge
does amplify into next week from around 592-593 dam entering this
weekend to around 596-597 dam during early next week. South-Central
Texas stays within the eastern influence of the ridge to where our
local 500 mb heights and 850 mb temperatures do also gradually
climb. Afternoon highs will climb into the triple digits for most
while upper 90s become common across the Hill Country. Persistence
of light to moderate southerly winds maintain and peak heat indices
are likely to climb into the 108 to 113 degree range for locations
outside of the Hill Country. Some locations in the Coastal Plains
may occasionally have heat indices exceed 113 degrees. Do expect a
return of heat headlines for portions of the region this weekend
with headlines likely to continue each day through the end of the
long term period. Proper heat safety will continue to be important
for those spending prolonged amounts of time outdoors. Overnights
stay very warm and humid as well with morning lows ranging from mid
to upper 70s into the low 80s. Rain chances lack this weekend into
next week as skies become mostly sunny to completely sunny each
afternoon.
&&
.AVIATION...
(00Z TAFS)
Issued at 619 PM CDT Wed Jul 5 2023
Isolated shower and weak storm activity is already diminishing with
the loss of daytime heating and no additional terminal impacts are
expected today. VFR flying conditions are forecast until MVFR cig
development between 07-09Z at the I-35 terminals and closer to 11Z at
KDRT. Improvement is likely to be a tad slower tomorrow, with VFR
skies returning around 15-17Z, earliest at KAUS. Isolated shower
activity could impact the I-35 sites briefly in the mid morning
hours, but there will be slightly better chances for afternoon
storms. While terminal impacts are no guarantee, a PROB30 group has
been introduced for the potential.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 77 92 76 97 / 20 40 0 10
Austin Bergstrom Intl Airport 76 91 74 95 / 20 50 0 10
New Braunfels Muni Airport 76 90 75 95 / 20 50 10 10
Burnet Muni Airport 75 92 74 96 / 10 30 0 0
Del Rio Intl Airport 78 96 76 96 / 0 10 10 0
Georgetown Muni Airport 76 92 74 96 / 10 40 0 0
Hondo Muni Airport 75 90 74 94 / 20 50 10 10
San Marcos Muni Airport 75 90 74 95 / 10 50 10 10
La Grange - Fayette Regional 76 90 74 95 / 20 50 10 20
San Antonio Intl Airport 77 89 75 95 / 20 50 10 10
Stinson Muni Airport 77 90 76 95 / 20 50 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...17
Long-Term...Brady
Aviation...KCW
Area Forecast Discussion
National Weather Service Green Bay WI
1026 PM CDT Wed Jul 5 2023
Updated aviation portion for 06Z TAF issuance
.UPDATE...
Issued at 844 PM CDT Wed Jul 5 2023
The risk of severe thunderstorms has ended this evening. However,
an upper level disturbance will move across the region this
evening. Convection has developed across northern Wisconsin with
this feature, thus expanded precipitation chances back to the
west to account for the new development of showers. A cluster of
showers and storms will move across southeast Calumet County
and Manitowoc County. This cluster could produce some locally
heavy rainfall, although totals should not get out of hand since
this cluster was moving northeast.
&&
.SHORT TERM...Tonight and Thursday
Issued at 616 PM CDT Wed Jul 5 2023
The latest RAP analysis and satellite/radar imagery show a poorly
defined cold front roughly stretching from just west of Marinette
to Lake Poygan early this afternoon. One small area of showers
moved northeast from Wautoma to the Bay of Green Bay during the
morning hours. These showers set back the heating curve over the
Fox Valley while lingering mid-level clouds have hindered low
level lapse rates. Further south and east, heating has been
largely uninterrupted with temps up to 87 degrees at Manitowoc.
This area from Calumet to Kewaunee to Manitowoc is the area with
the highest concern for strong or severe storms, and isolated
flooding for the rest of this afternoon into this evening.
Many of the convective allowing models show storms expanding
northeast into east-central WI as low level convergence
increases along the front with help from the lake breeze.
Scattered strong to isolated severe storms remain possible in this
area late this afternoon into early this evening. Mixed layer
instability to 1000 j/kg and deep layer shear of 25 to 30 kts
could lead to a strong straight line wind and hail threat.
Precipitable water values to around 1.75 inches and training
storms could also lead to heavy rainfall and isolated flooding for
urban and small streams. The showers or thunderstorms should exit
eastern Wisconsin during the late evening hours as the cold front
moves into Lower Michigan.
Clearing skies will move in behind the front from west to east
during the overnight hours. Lows should range from the lower 50s
in far north-central Wisconsin to the middle 60s near the lake
and bay.
Thursday should be partly sunny and pleasant, as a surface high
moves into the Western Great Lakes. Temperatures will be cooler
and range from the upper 60s over Vilas county to the upper 70s
over the Fox Valley.
.LONG TERM...Thursday Night Through Wednesday
Issued at 616 PM CDT Wed Jul 5 2023
Quiet conditions to start the long term forecast followed by a more
active pattern for the weekend into early next week with various
chances for showers and thunderstorms.
Thursday night through Friday...Dry and cooler conditions are
expected during this time period as a high pressure resides over the
forecast area. Low temperatures Thursday night will be below normal
with values ranging from the middle 40s in north-central WI to the
low 50s to middle 50s elsewhere. The typical cold spots may see
values a couple degrees colder due to the likelihood of clear skies
and calm winds. High temperatures on Friday will be around normal
with values ranging from the middle 70s to low 80s.
Weekend into Early Next Week...A closed upper-level low pressure
system centered over the southern Nunavut, Manitoba, northern
Ontario, and the western portion of Hudson Bay region through early
next week. A parade of shortwaves are expected to circulate around
this low into the Upper Mississippi Valley and provide multiple
chances for scattered showers and thunderstorms in the forecast
area. Models are still indicating a better chance for widespread
showers and thunderstorms on Monday and Monday night. However, the
latest guidance is showing some dry air in the mid-levels, which may
hinder the amount of precipitation and its coverage. Beyond Monday
night, models disagree with the evolution of the upper-level low. A
general consensus has the low continuing to circulate somewhere
over Ontario, keeping additional chances for showers and
thunderstorms in the forecast.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1020 PM CDT Wed Jul 5 2023
VFR conditions will continue through Thursday night. The only
exception would be for some patchy MVFR/IFR CIGS and VSBYs
across the far north towards sunrise on Thursday morning. The
greatest potential for fog will be across Vilas County. Fair
weather cumulus clouds will develop by late morning from four to
five thousand feet rising to six to eight thousand feet during
the afternoon. The fair weather cumulus clouds will dissipate
around sunset on Thursday. North/northwest winds will gust to
near 15 knots Thursday afternoon, then winds will become light
and variable Thursday evening.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.........Eckberg
SHORT TERM.....MPC
LONG TERM......Kruk
AVIATION.......Eckberg
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1011 PM EDT Wed Jul 5 2023
.SYNOPSIS...
Seasonably warm and humid conditions will continue through the
weekend. Daily chances for mainly afternoon and evening
thunderstorms remain in the forecast for the foreseeable future.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 1000 pm EDT: Coverage of slowly-moving and weak convection
remains decent late this evening around the CLT metro area and along
the eastern escarpment of the mountains and the adjacent NC
foothills. The late evening HRRR runs have trended toward quick
diminution of the coverage across the region through midnight, but a
very moist boundary layer along with outflows moving about the
region suggest that scattered convection will linger longer than the
CAMs predict into the overnight hours across the NC Piedmont. PoPs
will thus trend down much more slowly in these areas. Until the
showers and embedded storms fade, isolated hydro problems from very
slow moving cells and deep warm layers will be the primary concern.
Fog and low cloud development will then be the main concern for the
pre-dawn hours, with some drying at mid and upper levels atop the
very moist boundary layer. Expect some fog, but dense fog may be
difficult to come by given the moisture depth and some stratus
development. Min temps should be close to normal.
With the weak upper trough axis expected to shift east of the area
on Thursday, and higher PWAT air shunted to the east as well, a
slightly drier boundary layer is expected. Further, lapse rates are
expected to be weak and the synoptic pattern overall less favorable
for convection. Nevertheless, moderate instability is expected to be
realized under sunnier conditions, and isolated to scattered deep
convection is expected during the afternoon, generally warranting 20-
40 PoPs across most of the area with predominantly a mountain focus.
An isolated pulse severe storm or two cannot be ruled out. Max temps
should return to normal, perhaps even a degree or two above.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 130 PM Wednesday: Another weak impulse will ripple through a
quasi-zonal flow aloft on Friday, while a weak frontal boundary sags
southeastward into the region. The combination of these features
should enhance convective coverage, with 1500-2500 J/kg sbCAPE
and elevated PWATs. Bulk shear remains weak, however, so severe
threat should be limited to a few pulse storms. The heavy rain
threat may tick up, however, as storms may be slow movers. Temps
will be near a category or so above normal.
A broad longwave trough will dig over the MS Valley Saturday,
with height falls to our west. Shortwave energy will ride through
the trough and cross our area sometime Saturday or Saturday
night. Typical early July heat and humidity should support at least
climo coverage of convection Saturday aftn and evening. Instability
does not look impressive in the guidance, so severe threat is
expected to be low, despite decent convective coverage.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 215 PM Wednesday: A broad upper trough will set up over the
eastern CONUS by Sunday. The 05/12z guidance has come in deeper with
an embedded shortwave trough across the OH Valley late Sunday into
Monday, with the wave even closing off into a 578-582 dam upper low
over the Central Appalachians by 00z Tuesday. This trend may result
in slightly below normal temps and lots of cloud cover, with above
climo PoPs through at least Monday. The low opens back up into a
trough and shifts east, but a broad, shallow longwave trough lingers
across the eastern CONUS through at least midweek. Dry air works
in from the west within the flat flow, so PoPs trend toward below
climo by Wednesday, with slightly below normal to near normal temps.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Convection persists around the KCLT airport
late this evening, but it will be very spotty near the other
terminals. Will ride mainly on VCSH/VCTS at the mountain and
foothill TAF sites, but keep TEMPO TSRA with gusts going at KCLT
through 03Z and then VCSH into the early overnight hours. Drying at
mid/upper levels overnight will increase the potential for fog and
low stratus development. Will confine any IFR or less mention to
KAVL and the mountain valleys at present, but cannot rule out some
IFR stratus arriving from the east at KCLT toward daybreak. Winds
will be light, with directions hard to pin down given the weak
surface pressure pattern through the period. Isolated to scattered
afternoon convection will return with heating on Thursday after the
morning low clouds dissipate.
Outlook: Rather typical summer weather is expected to continue
through the late workweek and into the weekend, with diurnal
convection expected each day. Early morning fog/low stratus will
also be possible each day, primarily in mountain valleys and
locations which saw heavy rainfall the previous afternoon.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...HG/JDL
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...HG
Area Forecast Discussion
National Weather Service Indianapolis IN
917 PM EDT Wed Jul 5 2023
.Forecast Update...
Issued at 916 PM EDT Wed Jul 5 2023
- Isolated Showers/Storms linger overnight; Most remain dry
Surface analysis this evening shows low pressure near Chicago, with
a trailing cool front across Central Illinois to south central MO.
Radar shows an area of thunderstorms ahead of the front over eastern
Illinois. This area of showers and storms has been diminishing upon
approach as it encounters a less favorable environment for
convection across Central Indiana. Aloft, water vapor shows a broad
tough in place over Central Canada and the northern plains, with an
embedded short wave ahead of this trough axis over the mid-
Mississippi Valley. Plentiful mid and upper level moisture was seen
on water vapor with this feature. SBCAPE across central Indiana was
near 2500 J/kg, but shear was quite limited.
HRRR and RAP continue to show the convection to the west will
continue to diminish upon approach as daytime heating continues to
wane along with expected instability. CAMS do show a stray TSRA/SHRA
passing across central Indiana overnight as the upper short wave and
trough axis pass, but limited instability should keep this rather
limited. Will continue to use minimal pops overnight to account for
the stray shower.
Given dew points in the upper 60s near 70, overnight lows near 70s
will be on the mark.
&&
.Short Term...(This evening through Thursday)
Issued at 301 PM EDT Wed Jul 5 2023
* Isolated airmass thunderstorms possible late today...trending to a
few strong to severe evening storms over western counties.
* Fog possible after midnight, especially in/near areas of greater
rainfall
Late today and Tonight...
The short term will find central Indiana amid overall zonal flow
between a broad and somewhat pronounced upper trough over interior
and northern North America and any semblance of a hot, midsummer
upper ridge suppressed to the Four Corners and southern Plains
states. Meanwhile a rather weak cool front riding along the
southeastern extent of the interior trough will approach and cross
the region, bringing mainly non-severe convection late today and
this evening... before generally fair and noticeably milder weather
builds into Indiana on Thursday.
Ample instability is expected over the western half of the region
within the 21z-03z timeframe this evening...as well as across north-
central zones at least briefly around 00z. Focus for strongest
convection will be the Wabash Valley, with upwards of 3000 J/kg of
SBCAPE expected near the Terre Haute and Vincennes areas. However,
limiting factors include no impressive 700-500mb lapse rates and
mediocre vertical wind shear per better dynamics holding back just
west of central Indiana. A mesoscale circulation to our west should
help to focus greater chances for severe winds northward through
Illinois and overall away from the local region. Therefore, and
following the SPC Marginal risk for the western tier, expect
numerous showers and scattered thunderstorms during mainly evening
hours...with isolated marginally strong/severe winds along the
Wabash Valley. Numerous showers/t-storms should diminish in coverage
through the late night despite the actual cool front progged to
start entering the region during the pre-dawn. Upstream zonal flow
aloft will extinguish any upper-level forcing with the boundary
passage. Nonetheless expect at least isolated showers to continue
across the region through daybreak.
Precipitable water values through late day today will be adequate
for mid-summer with moSCT to briefly BKN cumulus will continue this afternoon under some
SCT/BKN mid/high level clouds. Isolated showers/storms may develop
as early as 20z, but confident coverage and probability too low to
include in TAFs.
Guidance is continuing to show convection after 00z this evening
moving from west to east, with embedded strong to possibly
marginally severe t-storms along the Wabash Valley through 4z.
Isolated thunder also expected at KIND/KBMG but decided to remove
from TAF with noticeable decrease in confidence from latest data. At
least isolated convection should continue through the overnight, yet
confidence again too low to include in TAF, especially with focus
towards dawn likely over more eastern portions of Indiana.
Weak cool frontal boundary to begin to slowly cross central Indiana
through AM hours Thursday. Moderate confidence in MVFR ceilings at
KLAF around 10-16z following this passage. Winds sustained under 10
kts will veer to west-northwesterly by 18z Thursday.st locations
sporting about 1.50 inches in the column. However, Pwats will
surge this evening ahead of the approaching boundary courtesy of
south-southwesterly flow, with a peak of upwards of 2.00 inches
crossing the CWA overnight. The lag in this timing following peak
heating should limit coverage of heavier downpours to mainly along
the Wabash Valley. Guidance continues to suggest overall limited
precipitation amounts, with 0.10-0.50 inches expected for most
locations through the short term...while locally 1.00-1.50 inches
is possible across western and northern counties...with a few
places south/east of Indianapolis likely not receiving measurable
rainfall. Flash flooding is not expected with current 3-hr
guidance of 2.00 inches or greater for essentially the entire
region, and areas with more sensitive tolerances over southeastern
zones offset from where any heavier precipitation is expected.
Surface conditions approaching saturation after 06z will promote at
least patchy fog, especially in areas where any heavier rain falls
this evening. Light southerly winds sustained around 5 mph should
prevent more organized areas of fog over most of the region.
Dewpoints will guide overnight lows with upper 60s to around 70F
prevalent by dawn.
Thursday...SCT to briefly BKN cumulus will continue this afternoon under some
SCT/BKN mid/high level clouds. Isolated showers/storms may develop
as early as 20z, but confident coverage and probability too low to
include in TAFs.
Guidance is continuing to show convection after 00z this evening
moving from west to east, with embedded strong to possibly
marginally severe t-storms along the Wabash Valley through 4z.
Isolated thunder also expected at KIND/KBMG but decided to remove
from TAF with noticeable decrease in confidence from latest data. At
least isolated convection should continue through the overnight, yet
confidence again too low to include in TAF, especially with focus
towards dawn likely over more eastern portions of Indiana.
Weak cool frontal boundary to begin to slowly cross central Indiana
through AM hours Thursday. Moderate confidence in MVFR ceilings at
KLAF around 10-16z following this passage. Winds sustained under 10
kts will veer to west-northwesterly by 18z Thursday.
The cool front will cross the local region through the morning and
midday hours without too much fanfare...isolated to widely scattered
light showers and perhaps a couple rumbles of non-severe thunder can
be expected. A similar thermodynamic setup will continue into
Thursday with any potentially stronger thunderstorms awaiting
afternoon instability amid the low-sheared profile. Cannot rule out
an isolated stronger afternoon storm along the CWAs far east and far
southern zones amid the convergence from the departing boundary. Any
further rainfall would be mainly light.
Winds under 10 mph will veer to westerly from west to east during
the morning...before moderate northwesterly breezes take over within
the passing frontal zone during the afternoon. Recent humid
conditions should see a modest, perhaps 5-degree drop in dewpoints
by late day. It will be the mildest day for most locales in about a
week, with high temperatures ranging from upper 70s over north-
central counties to mid-80s south/east of Bloomington.
&&
.Long Term...(Thursday night through Wednesday)
Issued at 301 PM EDT Wed Jul 5 2023
* Brief period of dry weather for late week
* Seasonably cool through much of the period
* Periodic storm chancSCT to briefly BKN cumulus will continue this afternoon under some
SCT/BKN mid/high level clouds. Isolated showers/storms may develop
as early as 20z, but confident coverage and probability too low to
include in TAFs.
Guidance is continuing to show convection after 00z this evening
moving from west to east, with embedded strong to possibly
marginally severe t-storms along the Wabash Valley through 4z.
Isolated thunder also expected at KIND/KBMG but decided to remove
from TAF with noticeable decrease in confidence from latest data. At
least isolated convection should continue through the overnight, yet
confidence again too low to include in TAF, especially with focus
towards dawn likely over more eastern portions of Indiana.
Weak cool frontal boundary to begin to slowly cross central Indiana
through AM hours Thursday. Moderate confidence in MVFR ceilings at
KLAF around 10-16z following this passage. Winds sustained under 10
kts will veer to west-northwesterly by 18z Thursday.es return
Saturday through next week
.Friday...
The extended period begins with a brief period of dry weather for
Indiana on Friday before a more active weather pattern develops this
weekend into next week. An area of high pressure quickly shifts
eastward through the region Friday. A drier environment in addition
to a subsidence inversion under the high should keep the environment
capped on Friday preventing convective activity across Central
Indiana. Expect highs to be seasonably "cool" for this time of year
in the low to mid 80s SCT to briefly BKN cumulus will continue this afternoon under some
SCT/BKN mid/high level clouds. Isolated showers/storms may develop
as early as 20z, but confident coverage and probability too low to
include in TAFs.
Guidance is continuing to show convection after 00z this evening
moving from west to east, with embedded strong to possibly
marginally severe t-storms along the Wabash Valley through 4z.
Isolated thunder also expected at KIND/KBMG but decided to remove
from TAF with noticeable decrease in confidence from latest data. At
least isolated convection should continue through the overnight, yet
confidence again too low to include in TAF, especially with focus
towards dawn likely over more eastern portions of Indiana.
Weak cool frontal boundary to begin to slowly cross central Indiana
through AM hours Thursday. Moderate confidence in MVFR ceilings at
KLAF around 10-16z following this passage. Winds sustained under 10
kts will veer to west-northwesterly by 18z Thursday.on Friday
with dew point values in the 50s.
.Saturday through Mid Next Week...
Active weather pattern with daily chances for thunderstorms arrives
this weekend and persists into next week. Northwest flow pattern
sets up aloft from the Northern Plains to the Ohio Valley as upper
ridging builds over the Southwest and troughing deepens over
Ontario. Disturbances riding southeastward within the jet stream
into the region will interact with a low level boundary pushing
through the area this weekend into early next week resulting in
multiple rounds of showers and thunderstorms. While confidence is
high in a warm, humid, and stormy pattern setting up, confidence is
low this far out on exact location, timing, and evolution of
mesoscale features. Where the attendant surface boundary ends up
will determine where periodic chances for storms exists into the
middle of next week. Should the upper trough amplify further which
some of the 05/12Z model data is hinting at...it could push the
primary zone for convection south of central Indiana early next week
before relaxing and enabling convection to shift back north into the
region. Right now highest confidence in storms over Central Indiana
is Saturday and Sunday with more uncertainty going into early next
week. With this pattern, the potential is there for severe weather
at times with any round of storms. It is too soon to determine
specific hazards due to uncertainty with the mesoscale details.
Still a lot to be fleshed out in this pattern...but the main
takeaway is that convective chances will likely increase from
Saturday into the middle of next week. The influence of the upper
trough will keep temperatures slightly cooler for July as
well...with highs confined to the lower and mid 80s into next week.
&&
.Aviation...(00Z TAF Issuance)
Issued at 617 PM EDT Wed Jul 5 2023
Impacts:
* Showers and storms possible after about 00z-04z this evening,
mainly at KLAF/KHUF.
* MVFR and Brief IFR conditions possible with
any TSRA.
Discussion:
Line of TSRA over Central Illinois continues to make slow progress
east toward the Wabash valley this evening. CAPE and shear across
Central Indiana continue to be less favorable for continued
convection across Central Indiana. Thus a slow diminishing of
coverage and intensity of the storms is expected upon approach.
Still the ongoing storms should have enough momentum to reach HUF and
LAF between 00Z-02Z causing brief visibility restrictions.
All of these storms are associated with daytime heating combined
with a weak upper short wave that will be pushing across Central
Indiana Overnight. HRRR continues to shows these storms falling
apart this evening and overnight. Thus overall, we have used
prevailing TSRA across western areas early on where confidence is
high, but diminished to VCTS late this evening and overnight as
coverage and intensity is expected to diminish.
Mainly VFR is expected on Thursday, but brief MVFR cigs will be
possible during diurnal minimums.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Puma
Short Term...AGM
Long Term...CM
Aviation...Puma
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1050 PM CDT Wed Jul 5 2023
.SHORT TERM... (Through Late Thursday Night)
Issued at 209 PM CDT Wed Jul 5 2023
Thunderstorms have developed across the central CWA along a old
outflow boundary early this afternoon. Expect storms to continue to
develop along and ahead of the this boundary into the early evening
as MLCAPES will be in the 2000-3000 J/kg range. Deep layer shear is
weak which does not support organized convection, but there is a
weakening MCV moving across the area that is helping to generate the
lift for the storms. The SPC microburst composite and hail
parameters are both suggest the potential for isolated severe
thunderstorms through early this evening.
Surface analysis is showing the actual cold front over eastern Iowa
and northwest Missouri. Latest RAP has this front moving southeast
through the CWA tonight. Expect most of the rain to move east and
south of the area by late this evening. Will keep with a chance of
showers and thunderstorms over parts of central and southeast
Missouri into southwest Illinois on Thursday as the GFS/NAM are
showing a weak shortwave trough moving quickly from the central
Plains into the mid South.
Lows tonight will be close to normal and temperatures on Thursday
and Thursday night will be a bit below normal with cold air
advection behind the front.
Britt
.LONG TERM... (Friday through Next Wednesday)
Issued at 209 PM CDT Wed Jul 5 2023
There is good agreement amongst the ensembles that the upper pattern
will become more amplified over the weekend into early next week as
an upper ridge builds over the Rockies and a upper low deepens near
Hudson Bay. This will cause the quasi-zonal flow over the area on
Friday to turn northwesterly by early next week. Within this flow,
the deterministic models are showing multiple shortwave troughs
moving through Missouri and Illinois Friday through Sunday with a
surface trough moving across the area on Saturday. Will keep
chances for showers and thunderstorms going through the weekend with
likely/categorical PoPs Friday night into Saturday. Chances will be
lower Monday into Tuesday as a surface high moves across the area
before another trough moves into the area by the middle of next week.
Temperatures Friday through Sunday will likely be below normal with
the clouds and the chance for rain. Highs will be climb closer to
normal by next week as 850mb temperatures climb into the 15-20C
range and the surface flow turns out of the southwest. This is
reflected well in the ensemble temperature plumes including the NBM.
Britt
&&
.AVIATION... (For the 06z TAFs through 06z Thursday Night)
Issued at 1047 PM CDT Wed Jul 5 2023
VFR conditions are expected to prevail over the TAF period. Light
winds from the northwest will veer to the northeast as a cold front
passes through the Mid-Mississippi Valley. Fog potential exists over
the next few hours in Northeast Missouri and West-Central Illinois,
including KUIN. However, confidence in fog development is low as
cloud cover will inhibit radiative cooling and drier air is
advancing south following the cold front. As a result, fog is not
included in the TAF.
JZ/MRB
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Reno NV
121 PM PDT Wed Jul 5 2023
.SYNOPSIS...
Seasonable weather for July is expected through the weekend with
warm temperatures, afternoon breezes, and isolated thunderstorms
possible. Most rivers and streams will remain fast flowing. Hotter
temperatures are possible next week.
&&
.DISCUSSION...
* Troughing along the West Coast and N California coupled with
above normal moisture will promote isolated t-storms each
afternoon through Friday. Main areas to watch are NE California
and far NW Nevada, with probabilities ranging from 10-30% each
day based on NBM and HRRR guidance. Typical impacts expected:
outflow winds 30- 40 MPH, lightning, and brief downpours of 0.5"
or so.
* Elsewhere, mainly typical July conditions are expected with
slightly above normal temperatures (low 90s W Nevada) and
westerly breezes 20-30 MPH each afternoon through the weekend.
There are signs in the ensemble guidance of the SW ridge
rebuilding next week leading to warmer temperatures, to possibly
moderate/orange heat risk levels. NBM showing mid to maybe
upper 90s in W Nev.
* Can`t rule out some haze affecting Alpine, N Mono, and adjacent
counties in Nevada next 1-2 days from the Bone Fire NW of
Yosemite, per latest HRRR Smoke simulations. This assumes active
fire behavior which is TBD.
* Rivers and streams in the Eastern Sierra will continue to run
full, fast, and cold through the upcoming weekend. But based on
latest RFC projections mainly minor flooding impacts are
anticipated including along the Walker River, where reservoir
management of inflows is helping limit river levels on the
mainstem. Flows could head higher next week if that additional
warming pans out, especially on streams in the Eastern Sierra,
but we`re getting to the point with the snowpack melting where
subsequent peaks would be hard pressed to exceed what we`ve
already seen.
-Chris
&&
.AVIATION...
Typical July weather over the next few days with warm temps and
gusty afternoon/evening winds of 20-25 knots for most areas. Can`t
rule out isolated t-storm cells N of SVE today and tomorrow,
roughly about a 20% chance. Some haze is possible from a new fire
NW of Yosemite, per latest HRRR Smoke model, affecting mainly
areas between MEV and MMH in the E Sierra with patchy VFR/MVFR
haze. Fire activity today will of course be a big factor in that.
-Chris
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
Area Forecast Discussion
National Weather Service Seattle WA
900 PM PDT Wed Jul 5 2023
.SYNOPSIS...Dry and warm conditions continue across Western
Washington as high pressure remains over the region, maintaining
heightened fire weather concerns. Temperatures will peak across
interior areas today, cooling slightly on Thursday then cooling to
near normal this weekend as a weak upper trough arrives. Dry
conditions will prevail except for a chance of showers and
thunderstorms along the Cascades crest.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...No significant changes to
the forecast this evening. Cascade convection will die off quickly
with loss of daytime heating. Onshore flow is developing this
evening, but inland intrusion of marine air is likely to be shallow
and limited overnight. The end result will be several degrees more
of cooling for coastal locations, but interior areas will be
marginally cooler at best on Thursday. Onshore gradients ramp up
further late Thursday as upper trough starts to drop down into our
area from British Columbia. This will cool temperatures back to just
above seasonal norms and pull the marine layer into parts of the
lowland interior Friday morning. Previous discussion follows with
updates to marine/aviation portions. 27
Heat, air quality/visibility, and fire weather have
been the primary concerns today. See the Fire Weather section for
additional fire weather details.
Heat: As of noon, temperatures from Everett southward were running 3-
6 degrees warmer than 24 hours ago, meanwhile along the coast and
north interior temps were at or below those from this time yesterday
courtesy of slightly stronger onshore flow and a weak wave brushing
the area. In general, today is still on track to be the warmest of
the week for the bulk of the Puget Sound metro area with HeatRisk
values topping out in the Moderate/Orange category. As onshore flow
will gradually strengthen Thursday cutting temperatures down
slightly. By Friday, temperatures will fall back down closer to
seasonal norms and persist well into the weekend.
Visibility/Air Quality: Smoke from 4th of July activities combined
with incoming wildfire smoke from BC and a few of local fires to
create degraded air quality this morning. Conditions have improved
through the day and will continue to do so thanks to effective
mixing. Expect some smoke/haze to remain around through Thursday
before onshore flow largely clears out the area Friday. The
exception could be areas downstream of any remaining fire activity.
With winds becoming more onshore Thursday afternoon/evening, the
HRRR Smoke model does suggest the potential for smoke to be directed
towards the Seattle metro area from the McEwan fire in Mason County.
That is completely dependent on whether that fire is still burning
and producing significant smoke. Please refer to local air quality
agencies for specific air quality forecasts and guidance.
The other item of note will be a 15-30% chance of shower or
thunderstorm activity over the North Cascades this afternoon and
evening. With relatively warm and dry conditions near the surface,
this does raise concerns for impacts from lightning and gusty
outflow winds. Chances for activity will decrease below 20% on
Thursday before returning Friday into the weekend.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...By Sunday, a weak and loosely
organized upper level low/trough will be situated off the WA coast
and general troughiness will be favored in that location through the
next week or so. This will continue to favor onshore flow into the
area with temperatures near to slightly above normal for mid-July
and diurnally driven showers/thunderstorms over the mountains.
-Wolcott-
&&
.AVIATION...Weak upper level trough moving into the area Thursday
with northwesterly flow aloft. In the lower levels thermally induced
trough moving east of the Cascades with the flow turning onshore
Thursday.
Just a few high clouds through Thursday for most locations. Stratus
moving up the Oregon coast overnight will get to KHQM around 12z
with ceilings below 1000 feet for most of the day. Late day
convection possible again over the North Cascades Thursday.
KSEA...Just a few high clouds. Northerly winds 4 to 8 knots
switching to southwest 12z-15z. Winds trying to become northwesterly
later Thursday afternoon but will end up in the 250-270 degree
range. Felton
&&
.MARINE...Thermally induced surface trough moving east of the
inland waters tonight with weak onshore flow developing. Small craft
advisory winds in the Central and Eastern Strait easing late
tonight. Small craft advisory winds over the outer coastal waters
also easing late tonight.
From Thursday through the weekend, onshore flow will dominate,
bringing strong westerly pushes of wind down the Strait each evening
and overnight period. Opted for SCA level winds through the Strait
Thursday afternoon with gales possible Friday evening/Friday night.
Stronger pushes down the Strait each evening/night from Thursday
through the weekend will likely make for SCA level winds over the
adjacent waters of Admiralty Inlet and the Northern Inland Waters.
Sub- advisory winds expected over remaining waters. Kristell/Felton
&&
.FIRE WEATHER...Dry, warm, and unstable conditions will continue
through this afternoon for elevated to critical fire weather
conditions. The Red Flag Warning continues for zones 655 (Black
Hills/Chehalis River Valley) and 659 (West Slopes of the Central
Cascades) with current RH values generally ranging 20 to 30 percent
in these areas. RH values elsewhere also remain borderline Red Flag,
especially for the Olympics, along with Mid Level Haines values of 6
for most of the area. The potential for isolated thunderstorms also
exists for the North Cascades, mainly of Whatcom and Skagit
Counties, into early this evening. Any thunderstorms may lead to
additional fire starts and breezy outflow winds.
Onshore flow increases on Thursday across the area, providing a
boost to the RH values, although low RH values will likely continue
along the Cascade crest. The threat for isolated thunderstorms in
the mountains will also continue into at least Saturday, mainly for
the North Cascades, with the best potential on Friday. Upper
troughing will decrease critical fire weather conditions otherwise
into early next week. JD
&&
.HYDROLOGY...The daily hydrology discussion has ended until the
start of the next rainy season; it will only be updated as needed.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Red Flag Warning until 7 PM PDT this evening for Black Hills and
Southwest Interior Lowlands-West Slopes of the Central
Cascades Generally above 1500 Feet.
PZ...Small Craft Advisory from 5 PM this afternoon to 3 AM PDT
Thursday for Central U.S. Waters Strait Of Juan De Fuca-
East Entrance U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 5 PM Thursday to 5 AM PDT Friday for
Central U.S. Waters Strait Of Juan De Fuca-East Entrance
U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory until 5 AM PDT Thursday for Coastal Waters
From Cape Flattery To James Island 10 To 60 Nm-Coastal
Waters From James Island To Point Grenville 10 To 60 Nm-
Coastal Waters From Point Grenville To Cape Shoalwater 10
To 60 Nm.
&&
$$