Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 07/23/23
Area Forecast Discussion
National Weather Service Denver/Boulder CO
845 PM MDT Sat Jul 22 2023
.UPDATE...
Issued at 843 PM MDT Sat Jul 22 2023
The couple of showers and storms popped up over northeast Colorado
earlier this afternoon have fully dissipated and skies tonight
will be mostly clear. Forecast for tomorrow looks on track, with
renewed isolated convection in the afternoon. Will be notable
drier at the surface and DCAPE values progged to be quite high, so
localized gusty winds can be expected in the vicinity of any
elevated showers or thunderstorms Sunday.
&&
.SHORT TERM...(This afternoon through Sunday)
Issued at 159 PM MDT Sat Jul 22 2023
Radar this afternoon only show a few weak showers across our
forecast area. GOES Water Vapor imagery shows little moisture in
the region downstream of an upper level ridge over the Colorado
Plateau. Given meager instability shown by SPC Mesoanalysis and
recent ACARS soundings at DEN, it`s unlikely we`ll see much more
activity this afternoon, though a few weak/gusty showers will
continue into the evening. Temperatures are crawling through the
upper 80s in most spots with highs across the plains peaking close
to 90F.
The upper ridge is expected to strengthen and drift eastward on
Sunday. Mid-level temperatures warm 2-4C across the region, which
should lead to highs 5-10F warmer than today. Late afternoon cloud
cover may limit things a bit, but highs should peak in the mid to
upper 90s across most of the lower elevations. Additional
weak/gusty showers will be possible again Sunday afternoon into
Sunday evening as a bit of mid to upper level moisture seeps into
the region. Models soundings show deeply mixed, inverted-V
soundings with plenty of DCAPE... so even the weakest showers that
develop tomorrow could produce some briefly strong gusts across
the Front Range into the I-25 corridor.
.LONG TERM...(Sunday night through Friday)
Issued at 159 PM MDT Sat Jul 22 2023
Hot weather will be the main story for the next couple days,
although we`ll also have some strong and gusty outflow winds from
high based showers and storms.
Sunday evening, considering DCAPE near 1500 J/kg and a fully
mixed airmass/dry adiabatic lapse rates to near 530 mb, isolated
high based showers/sprinkles with strong, gusty microburst winds
may linger into the mid evening hours. Temperatures will be warm
overnight, although a somewhat drier airmass and light winds will
lend itself to modest radiational cooling.
For Monday, the upper level ridge axis and thermal ridge will
shift further east, aligning almost directly over Wyoming into
Central and Western Colorado by afternoon. This will support hot
temperatures, with highs soaring into the upper 90s across the
plains, with a couple spots hitting 100. Those daytime highs will
put us very close to Heat Advisory criteria, and decision on that
will be made tonight or Sunday morning to allow for 24 hour
advance notice. Mid and upper level moisture is expected to
increase slightly under the ridge, enough for isolated to
scattered high based showers and a couple storms. Strong, gusty
outflow winds will be likely, considering DCAPE near a whopping
1700 J/kg.
For Tuesday, Wednesday, and Thursday, the flow aloft becomes more
zonal as a couple shortwaves push across the Canadian/US border
and flattens the ridge. Mid level moisture is forecast to be drawn
around the ridge in westerly flow aloft, supporting scattered but
still high based showers and a few storms. A couple storms with
more appreciable rainfall will be possible given the uptick in
moisture. Temperatures will remain above normal, but there should
be slight cooling due to more clouds, cooling aloft, and scattered
afternoon convection.
For Friday into the next weekend, ensembles point to stronger
upper level ridging across the Central Rockies again. This would
lead to temperatures warming back to several degrees above normal
after the brief and slight mid week cooling. This time, there may
be additional but marginal monsoonal moisture stuck under the
ridge, so we should see a continued chance of storms each
afternoon and evening.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 532 PM MDT Sat Jul 22 2023
VFR conditions expected through the TAF period for all terminals.
Isolated, high-based SHRA or TSRA are moving off the foothills and
into the plains at this hour, but these should be on the weaker
side and shortlived. Confidence in impacts to KDEN remain low and
will thus continue to leave out of the TAF. That said, cannot rule
out brief VRB gusts to 25-30 kts in the event a high-based shower
moves through the vicinity.
Otherwise, expect gradual CW rotation from NE winds to transient
SE wind before becoming SW drainage overnight. Light and variable
winds Sunday morning will become prevailing northeasterly in the
afternoon with high-based showers again bringing a possibility of
gusty outflow winds, mainly after 22Z.
&&
.HYDROLOGY...
Issued at 159 PM MDT Sat Jul 22 2023
Drier conditions can be expected, although a few storms will
develop each afternoon and evening. For the most part these
storms will be weak and produce light rain. There is only a very
limited threat of flash flooding in the burn scars.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Rodriguez
SHORT TERM...Hiris
LONG TERM...Barjenbruch
AVIATION...Rodriguez
HYDROLOGY...Barjenbruch
Area Forecast Discussion
National Weather Service Indianapolis IN
1203 AM EDT Sun Jul 23 2023
...Updated Aviation Discussion...
.Forecast Update...
Issued at 954 PM EDT Sat Jul 22 2023
Surface analysis early this evening shows a broad area of high
pressure in place stretching from the southern plains across the mid-
Mississippi valley to Central Indiana and Ohio. GOES16 shows mainly
clear skies across the forecast area, however there was one
lingering shower SE of IND. This convection was dissipating with the
loss of daytime heating.
Little change is expected overnight with mostly clear skies expected
along with light winds. Overall, little change in the ongoing
forecast with lows mainly around 60 expected, perhaps a little
warmer at IND.
Looking toward daybreak, a short wave over WI/IA was generating
convection. Some of this forcing could arrive in NW central IN near
12Z, and for now have included some very low chc pops at that
location.
&&
.Short Term...(This evening through Sunday)
Issued at 303 PM EDT Sat Jul 22 2023
-Isolated showers today, better chances for storms tomorrow.
Rest of Today.
As of early this afternoon, a dense diurnally driven cu field
dominates the skies. Showers have yet to form, but the latest ACARs
soundings show the environment is uncapped with 500-700 J/kg of SB
CAPE. Moisture availability remains the biggest hindrance to
convection with very dry air atop the boundary layer. Current
expectations are that showers will begin to form by 20Z with
isolated coverage through 00Z. Instability won`t improve much
beyond 750 J/kg, so think that the thunder potential/coverage would
be very minimal, but will continue to monitor the environment and
adjust POPs accordingly.
Tonight.
Quiet conditions are expected for the overnight hours with any
convection quickly dissipating by 01. The diurnally driven cu field
overhead will gradually dissipate after sunset as the PBL begins to
decouple. This decoupling will help to bring light to calm winds
and combined with the clearing will allow for efficient radiational
cooling through the night and bring near saturation conditions by
early tomorrow morning. Subsidence above the near surface inversion
isn`t great and moisture is even more marginal compared to this
morning,but wouldn`t be shocked to see localized ground fog above
the corn. Additional river valley fog may bring reduced visibilities
to low lying communities.
Sunday.
Similar conditions are expected for much of the day tomorrow with
dry weather for much if not all of central Indiana through the
morning hours, but a shortwave within the broader trough will bring
increased rain chances to the area during the evening into overnight
hours. Weak southerly flow during the daytime hours will bring a
gradual end to the sub 60 degree dewpoints and begin the warming
trend that will bring 90s by later in the week. This subtle
increase in near surface moisture will allow for better instability
later into the day and combined with the forcing associated with the
trough aloft, should allow for showers and storms as early as 18Z.
Convection will be primarily driven by diurnal heating, but could
see some additional thunderstorms into the overnight hours with a
strengthening LLJ to the west.
&&
.Long Term...(Sunday night through Saturday)
Issued at 303 PM EDT Sat Jul 22 2023
* Seasonably warm and humid with occasional thunderstorm chances
during the long term.
Models continue to show a briefly quite amplified pattern early in
the long term, leaving central Indiana in the crosshairs of large
scale troughing early in the period, then quasizonal or northwest
flow later in the week as the ridge flattens somewhat late in the
period.
Broadly speaking, this will result in seasonably warm and humid
conditions much of the week with multiple chances for thunderstorms
through the week.
Through the week, northwest flow will eventually become more
quasizonal as the ridge deamplifies. Subtle upper level disturbances
and daily ridge-riding convection will provide multiple
opportunities for thunderstorms, but cannot include more than slight
chance to low chance pops in any one period as uncertainty is high
in these situations, with convective evolution strongly dependent on
these subtle waves and prior convection, both of which larger scale
models handle quite poorly. One or more opportunities for severe
weather cannot be ruled out completely given the tendency for ridge
riding convection to develop organized cold pools even in
environments with modest deep layer shear. Damaging winds would be
the primary threat given the likely setups and climatologically
speaking.
While heights will increase through the week, NBM output appears to
be a bit too warm late in the period, and have made some downward
adjustments there. Will still be hot and sticky, particularly given
the relative lack of 90 degree weather thus far this season. Heat
will be far more significant under the ridge to our west, but max
heat index values will likely be well into the mid to upper 90s if
not near 100 at times mid to late week.
&&
.Aviation...(06Z TAF Issuance)
Issued at 1203 AM EDT Sun Jul 23 2023
Impacts:
* Mainly VFR conditions expected this period.
* Brief MVFR/IFR Fog will be possible near 12Z at LAF/HUF/BMG.
* Brief MVFR will be possible in Iso/Sct TSRA that could strike a
TAF site on Sunday afternoon.
Discussion:
High pressure across the area will continue to dominate Indiana/s
weather overnight. Clear skies are expected with light winds. Models
suggest dew point depression may fall to 1-3F at HUF, but could be
greater elsewhere. Nonetheless, with clearing skies and light winds,
have included a TEMPO group for IFR Fog at LAF/HUF?BMG during the
max cooling hours.
Models suggest a short wave progressing across Indiana on Sunday.
This in combination with a warm and humid air mass in place across
Central Indiana should allow for some sct convection during the max
heating hours. Forecast soundings show a bit more CAPE available on
Sunday comparatively to Saturday. Thus confidence remains low for
specific timing and location of any TSRA during Sunday afternoon,
but expected atmospheric conditions suggest favorable conditions for
at least a few showers or storms. Used a window to VCTS to account
for this.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Puma
Short Term...White
Long Term...Nield
Aviation...Puma
Area Forecast Discussion
National Weather Service Pendleton OR
858 PM PDT Sat Jul 22 2023
.UPDATE...Breezy to windy conditions are diminishing at this time.
There are still some stations, such as KDLS, KELN, KRDM and KBDN,
reporting breezy conditions. The forecast area will remain under
a southwest flow aloft. Both the deterministic and ensemble models
are in very good agreement in the short term with the synoptic
weather patterns.
Cross-Cascade pressure gradients will increase again on Sunday
afternoon and evening. This will combine with low relative
humidity to create critical fire conditions again Sunday afternoon
and evening (80-90%). A Red Flag Warning remains in effect
through Sunday evening for wind and low RH for western portions of
the Lower Columbia Basin from Dallesport and Goldendale east as
far as Boardman. A dry cold front is then expected to move across
the region on Monday, which will bring even stronger winds ahead
of and with the front. There will still be critically low RHs,
which will combine with these winds to cause a good potential for
Red Flag conditions (60-70%) again from Monday afternoon and early
evening. As such a Fire Weather Watch has been issued for the
southern portions of the WA Lower Basin, and northern portions of
the OR Lower Basin. The watch area will be from east of the
Columbia Gorge to the northeast border of the fire weather
district of the Lower Columbia Basin.
Maximum temperatures were a few degrees cooler today than Friday.
There will be a slight rebound in temperatures by a couple degrees
on Sunday, with highs in the mid to upper 90s in the lower
elevations, and 70s and 80s in the mountains. High temperatures
will then lower to the upper 80s to lower 90s in the lower
elevations on Monday as the aforementioned dry cold front moves
across the forecast area. These temperatures will be slightly
below normal or late July. High temperatures will then drop a few
more degrees on Tuesday to the mid to upper 80s in the lower
elevations and 60s to near 80 in the mountains. After that another
warming trend will begin for the rest of next week. 88
&&
.AVIATION...06z TAFs...VFR conditions will prevail during the
next 24 hours, with perhaps just a few mid and/or high clouds, and
possibly some smoke from area wildfires. Breezy winds will occur
at times again Sunday afternoon and evening at KDLS, KPDT, KRDM,
KBDN, and KALW, with speeds as high as 10-20 Kts. Winds will be
stronger at KDLS, with wind speeds of 15-25 Kts with gusts to 35
Kts mph Sunday afternoon and evening (confidence 70- 90 percent).
Wind direction will be mostly west to northwest. Visibilities
will remain above VFR minimums (P6SM) at all terminals at the
surface. However, smoke aloft may have some impacts on aircraft
flying through any smoke layers due to lowered visibility. 88
&&
.FIRE WEATHER...Relative humidity will drop as low as 15 percent
again Sunday afternoon and evening, with Cascade gap winds of 15
to 30 mph Sunday. This will create critical fire weather
conditions again for 3 to 5 hours in the afternoon and evening in
the westernmost portion of the Lower Columbia Basin of Oregon and
Washington from Dallesport and Goldendale as far east as
Boardman. A Red Flag Warning remains in effect until 10 PM Sunday
evening as a result. A dry cold front will then move across the
fire district on Monday. There will be a good potential for
critical winds and low RHs again ahead of and with the cold front
on Monday afternoon and early evening (confidence 60-70%). As a
result, a Fire Weather Watch has been issued for Monday afternoon
and evening for wind and low RH. This watch covers southern
portions of the WA Lower Columbia Basin (WA691) and mostly
northern portions of the OR Lower Columbia Basin (OR641), east of
the Columbia River Gorge, which will not have critical fire
conditions. 88
&&
.PREV DISCUSSION... /issued 346 PM PDT Sat Jul 22 2023/
SHORT TERM...Tonight through Monday Night...An upper ridge
remains centered over the eastern Idaho this afternoon though it
is slowly moving eastward as an upper low and trough moves closer
to the British Columbia coast. Tomorrow it will move to Wyoming
and western Montana as the upper low and trough moves even closer
to the coast. Weather tonight through tomorrow night will remain
fairly consistent to the last couple of days though the shifting
of the ridge will allow for cooling temperatures. Temperatures
tonight will be a couple of degrees cooler than last night with
lows in the lower to mid 60s in the Columbia Basin and mainly in
the 50s elsewhere. Tomorrow will be similar to today with highs in
the 90s with mid 80s to lower 90s in the mountains. Sunday night
lows will be similar to tonight. The primary forecast challenges
through Sunday night will be fire weather and air quality issues.
Pressure gradients along the Cascades will remain strong and the
Cascade gaps will have winds of 15 to 25 mph with higher gusts
this evening and perhaps a bit stronger again tomorrow afternoon.
Relative humidity remains at 15-20 percent in the afternoon which
will lead to a few hours of critical fire danger the western
portion of the Columbia Basin and Simcoe Highlands from The Dalles
and Goldendale to Boardman. Have already issued a Red Flag
Warning for that area through tomorrow evening. Areas in the
Columbia Basin will have lighter winds, so the fire danger is less
there. There will also be air quality concerns as the Simnasho
fire on the Warm Springs Reservation is sending smoke south into
southern Wasco and Jefferson Counties. Oregon air quality agencies
have issued an Air Quality Alert for that area through Monday
evening. To the north, the Newell Road fire east of Goldendale is
up to about 30,000 acres and is also putting out considerable
smoke which is being pushed eastward into the Columbia Basin, but
so far air quality numbers are not too bad.
As we get into Monday, the trough will move ashore near the
northern tip of Vancouver Island, sending a cold front into the
Pacific Northwest. This will give the Washington Cascades a chance
of rain showers on Monday and Monday night and into the Oregon
Cascades and adjacent areas as far as Ellensburg, Yakima and The
Dalles Monday night. The rest of the area will remain dry. The
Washington Cascade crest may get up to a quarter of an inch but
elsewhere should get just a few hundredths of an inch at most.
Temperatures will drop 5 to 8 degrees Monday with the frontal
passage to the 80s and lower 90s. Winds on Monday will be around
20 to 30 mph in the Columbia Basin and Gorge with 10 to 20 mph
elsewhere. While humidities will be higher (18-25 percent), the
stronger winds will keep fire danger concerns at the forefront.
Didn`t have the confidence just yet, but suspect the entire
Columbia Basin may need a Red Flag Warning on Monday. Perry/83
LONG TERM...Tuesday through Saturday...Not much change in the
messaging for the long-term forecast, as the PacNW will continue to
find itself under SW flow aloft through at least next weekend.
Ensembles continue to show our forecast area wedged between robust
high pressure over the desert SW and some kind of low pressure
system off the coast of BC. While the orientation of the low off the
BC coast shifts over the period, the overall pattern of SW flow
aloft remains relatively stagnant, with the impact on our weather
through the period being that of seasonable temperatures and
occasional periods of breeziness, primarily through the Cascade
Gaps.
As this BC low churns off the coast, only real concern as far as
sensible/fire weather impacts go will be the potential for this
system to circulate upper-level shortwaves across the interior NW,
which would lead to periods of breezy to windy conditions outside of
just the Cascade Gaps. RHs look to more or less be above critical
levels throughout much of the work week next week, but if an upper-
level system elevates the winds enough, critical conditions could be
met despite the more mild RHs. Looking at ensemble guidance, members
appear to key in on potentially Thursday or Friday seeing an
increase in winds due to this potential of an upper-level wave, but
confidence is low (<30%) on the timing and magnitude of the winds
should this be borne out. Otherwise, confidence is high (around 70%)
in the forecast next work week being primarily that of seasonable
temperatures, breezy conditions through the Cascade Gaps, and dry
weather. At least until next weekend, before ensembles start to
diverge in solutions once the BC low finally departs our area of
influence. Evans/74
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 59 94 62 87 / 0 0 0 0
ALW 64 97 66 92 / 0 0 0 0
PSC 67 98 68 93 / 0 0 0 0
YKM 62 95 60 87 / 0 0 0 10
HRI 65 98 66 92 / 0 0 0 0
ELN 59 92 59 83 / 0 0 0 10
RDM 53 92 52 86 / 0 0 0 0
LGD 59 96 60 92 / 0 0 0 0
GCD 58 98 58 94 / 0 0 0 0
DLS 63 94 61 85 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 10 PM PDT Sunday for ORZ641.
Fire Weather Watch from Monday afternoon through Monday evening
for ORZ641.
WA...Red Flag Warning until 10 PM PDT Sunday for WAZ691.
Fire Weather Watch from Monday afternoon through Monday evening
for WAZ691.
&&
$$
UPDATE...88
SHORT TERM...83
LONG TERM....74
FIRE WEATHER...88
AVIATION...88