Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/23/24
Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
438 PM AKDT Sat Jun 22 2024
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: This
afternoon through Tuesday)...
It has been a very warm day across Southcentral with northerly
winds bringing in dry air and warming most places into the 70s,
including Kodiak and Anchorage. Seward joined the 70 degree club
before the sea breeze kicked in and cooled them off. Temperatures
pushed the 80 degree mark in the Susitna Valley and some northern
sections of the Copper River Basin. The northern Susitna Valley
and northern Copper River Basin have been hot, dry, and windy
enough for a Red Flag Warning through 10 PM tonight which denotes
the potential for extreme fire behavior.
While there has been limited convection as of early this
afternoon, cumulus fields are seen on satellite building over the
Talkeetna Mountains and Alaska Range. This area should build
farther southward this evening with isolated thunderstorms
possible over mountains this afternoon and evening. Sunday looks
like a better day for thunderstorm potential as the airmass over
Southcentral will be more unstable. One item of note is that the
GFS, Canadian, and HRRR models are all indicating for some 500 mb
vorticity advection over the Kenai, Chugach, and southern
Talkeetna Mountains Sunday evening. Should this occur, there might
be more organized convection for these areas which would hold
together off the mountains allowing the thunderstorms to move over
the Mat-Su Valleys, Anchorage and the western Kenai Peninsula.
This is not a terribly strong signal, but in an unstable
environment it could cause increased thunderstorm development.
Monday and Tuesday will see continued afternoon and evening
showers and thunderstorms, especially over mountainous areas.
&&
.SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS
(Days 1 through 3)...
High clouds have persisted over much of the Middle Kuskokwim
Valley and Western Alaska Range on Saturday within the presence of
an upper trough. However, this has not prevented the development
of weak instability over the region. A few showers and
thunderstorms have already materialized over the Western Alaska
Range and to the north and northeast of Lime Village. Additional
wet thunderstorms will be possible across both the Middle
Kuskokwim Valley and Western Alaska Range through the evening
hours, as they meander generally southward. Temperatures on
Saturday have largely underperformed with high temperatures
struggling to get out of the upper 60s.
Sunday will likely be another day of cooler temperatures across
Southwest Alaska with areas of continued cloud cover. The trough
currently over the region should begin to meander southward,
allowing more breaks in cloud cover and another round of late
afternoon/evening showers and thunderstorms across the Middle
Kuskokwim Valley and Western Alaska Range.
Looking west, an occluded low skirting the Eastern Aleutians this
evening is forecast to drop southward into the North Pacific
through Sunday afternoon. Models are slowly coming into better
agreement with the arrival of the next upper low into the Western
Aleutians on Monday afternoon. This low will deepen into the 980
mb range while tracking just north of the Central Aleutians into
Tuesday. Expect widespread showers across the Western and Central
Aleutians on Monday with small craft easterly winds overspreading
the region over the latter half of the day.
BL
&&
.LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)...
The long term consists of a high amplitude ridge over the AlCan
border and a high amplitude trough over the Bering. This will lead
to fairly bimodal weather between the Bering/Southwest and
Southcentral. In general, the Bering and Southwest will be wetter
and cooler than what has been observed recently as a series of
shortwaves move from the Bering and into Southwest Alaska and the
west coast. Southcentral will likely be cloudier in this pattern,
though influence from the ridge will keep temperatures above
average with possibilities of breezy conditions and thunderstorms.
The main uncertainty in the forecast for Southcentral will be how
far east the shortwaves are able to make it, and therefor the
extent of convection and rain.
-Jones
&&
.AVIATION...
PANC...VFR will persist through the TAF period. Winds will
increase out of the south through the evening and then abate again
overnight. Most shower and thunderstorm activity will remain out
of Anchorage today, but cannot completely rule out a shower or
two making it near Anchorage. Probability of daytime showers or
thunderstorms is a slight bit higher on Sunday, as easterly flow
aloft will assist in the westward movement of any convection that
develops across the Chugach front range.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
930 PM MDT Sat Jun 22 2024
.KEY MESSAGES...
- Warmer and drier trend starting today, but cannot rule out
gusty winds with high-based storms in the afternoon near the
CO/WY border.
- Hot temperatures in the upper 80s to 90s are expected for
Sunday through much of next week. Elevations below about 4500
feet may exceed 100F.
&&
.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 225 PM MDT Sat Jun 22 2024
Frontal boundary lays pretty near Cheyenne this afternoon and
lays north of Cheyenne to Douglas into northeast WYoming. This
boundary is separating dewpoints in the 30s west of the front
with upper 40s/low 50 dewpoints in the Panhandle. Radar is
pretty quiet this afternoon. We did have some showers/storms
develop along the state line with Colorado out by Laramie...but
storm motions have been southeast into northern Colorado.
Current GFS 700mb temperatures at 21Z around +10C over the
northern Panhandle to +15C over southern Carbon County. This has
yielded temperatures across the CWA from the mid 80s in the
Panhandle to near 80 at Rawlins so far this afternoon. PWAT
values have really dried out as well with .65 inch near Sidney
and .49 inch out by Rawlins.
Not expecting much for afternoon convection across southeast
Wyoming this afternoon. Mesoanalysis RAP surface based CAPE
only around 500 J/KG through the afternoon. HRRR/RAP simulated
radar only showing a few storms across northern Colorado with
nothing really on our side of the state line. Any convection
that does develop this afternoon is expected to die off pretty
quickly as temperatures cool late afternoon/evening.
For Sunday...700mb temperatures climb to +14C across the
Panhandle to +16C across Carbon County. Look for highs Sunday in
the mid to upper 90s in the Panhandle to upper 80s/low 90s west
of the Laramie Range. Dry and sunny conditions expected.
Begin to see an increase in showers Monday...mainly west of the
Laramie Range during the afternoon. These will likely be high
based storms with little to no rainfall. ECMWF and GFS showing
an increase in moisture from the south in western Colorado
making its way into southern Carbon and Albany Counties.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 225 PM MDT Sat Jun 22 2024
Warm temperatures continue into the long term with near daily
chances for showers and thunderstorms. A ridge of high pressure over
the Desert Southwest will persist throughout much of next week. This
will lead to +14C to +18C 700 mb temperatures hanging over the CWA
through Friday. As a result, temperatures across much of the area
will be above average and roasty. Tuesday through Thursday will see
highs across much of the area in the upper 80s to 90s. Although the
region will be under the influence of a ridge, it is a dirty ridge,
with fairly decent precipitation chances on Wednesday and Thursday.
An upper-level disturbance moving across the ridge on Wednesday
could spark some scattered convection. GFS soundings for Wednesday
afternoon indicate that severe weather cannot be ruled out. Inverted-
V soundings and MUCAPE values up to 2000 J/kg in the Nebraska
panhandle could lead to a severe wind and hail threat. Model
soundings on Thursday do not look conducive for severe weather, but
another weak disturbance aloft could lead to another round of
afternoon storms.
By Friday, a shallow trough will begin enter the central Rockies,
cooling temperatures off a few degrees and brining more
precipitation chances. Once the cold front is through Friday
evening, expect a larger cool down, with highs near to slightly
below average on Saturday.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 928 PM MDT Sat Jun 22 2024
West northwest flow aloft will prevail with no precipitation due
to a relatively dry atmosphere.
Skies will be mostly clear. Winds will gust to 25 knots at the
Wyoming terminals from 15Z to 00Z.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...SF
AVIATION...RUBIN
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
844 PM CDT Sat Jun 22 2024
.KEY MESSAGES...
- A decaying line of thunderstorms will push into the area
tonight. Hazardous weather will not be widespread, but a few
locations will be susceptible to torrential rainfall,
lightning, and pockets of gusty thunderstorm winds.
- Afternoon temperatures will average about 5 degrees warmer than
climatology over the next week, with the hottest day of the
period coming Tuesday when heat index values could exceed
triple digits.
- Additional rainfall chances (greater than 50% probability) exist
by the middle of next week with an attendant severe weather risk
looming.
&&
.UPDATE...
Issued at 844 PM CDT Sat Jun 22 2024
Current forecast still looks on track with storms moving into the
area, probably after 9 pm. HRRR model seems to have the best
handle on current situation and think it`s best with the forecast
timing of any storms arriving. Besides the watch in effect for
parts of the CWA, did update pops/wx grids to account for slightly
slower timing of precip. New update should be coming our shortly.
Auten
&&
.DISCUSSION...
Issued at 151 PM CDT Sat Jun 22 2024
A quick check on features this afternoon reveals a compact mid-
level shortwave trough pushing across the Upper-Mississippi
Valley, with an attendant cold front extending from Green Bay to
Omaha to Dodge City. A narrow corridor of low-to-mid 70s sfc
dewpoints have pooled ahead of the this front, and convective
initiation is already occuring across portions of NE Iowa. Steep
low-level lapse rates and sufficient surface heating out ahead of
these features should help erode any remaining cap, while a mid-
level speed max (40-50 kts @ 500 mb) nosing in from the west helps
augment deep layer shear. The net effect will be clusters of
organized thunderstorms blossoming and pushing southeastward along
the cold front. CAMs remain in excellent agreement that such
activity will hold together as it sinks into central and southeast
Illinois late this evening.
An attendant severe weather risk remains in tact tonight, mainly
in areas north of a Beardstown-to-Bloomington line where the axis
of a 30-40 kt LLJ will be positioned. Damaging thunderstorm wind
gusts, associated with a mature cold pool, is the main concern by
the time the line reaches our forecast area. The expectation,
though, is for convective activity to steadily fade overnight as
the upper forcing (shortwave) becomes displaced too far northeast,
the low- level jet axis gradually narrows and pinches off while
convergence along the front weakens. In other words, thunderstorms
will become less organized with southeast extent, and areas south
of I-72 may not see much thunder at all.
Hydro has the potential to steal the show tonight, with a few CAM
members (notably the ARW, NAM Nest, and NSSL WRF) offering localized
amounts up to 3" anywhere north of that Beardstown-to-Bloomington
line. While this won`t be the rule by any means, it`s certainly a
plausible outcome given a healthy LLJ and PWATs along the front
that exceed the 99th percentile of mid-June climatology.
A marginal cool down is anticipated Sunday in the wake of frontal
passage, with afternoon highs mostly in the mid-to-upper 80s. This
will be short-lived, though.
By Monday, mid-level heights will steadily increase beneath a
plume of hot air surging northward out of the western Gulf.
Temperatures on Monday will eclipse 90 degrees in many areas, and
if the deterministic NBM gets close to verifying, Tuesday will
max out in the mid-to-upper 90s ahead of the next frontal zone
with heat index values potentially exceeding 100 degrees. Tuesday
is not necessarily a slam dunk Heat Advisory day, though, with
multiple failure modes in play. Chief among them is a nocturnal
MCS. While this signal is mostly muted in ensemble and multi-
model guidance, the global deterministic do show some semblance
of this possibility with a few shortwaves lurking upstream across
the Corn Belt.
Otherwise, our attention is focused on the frontal passage itself
Tuesday night into Wednesday. Given the very moist and unstable
air mass ahead of the front, its passage may be accompanied by an
attendant severe weather and hydro risk.
Another brief cool down is then anticipated Thursday into Friday
as modified Canadian high pressure settles over the Great Lakes
region. Afternoon highs will mostly be in the upper 80s during
this period. Nevertheless, another signal for hot and increasingly
humid weather returns late next week and into the weekend --
perhaps marking a return to mid 90s heat and an additional round
of thunderstorm activity.
MJA
&&
.AVIATION... (For the 00z TAFs through 00z Sunday Evening)
Issued at 647 PM CDT Sat Jun 22 2024
Convection has finally started firing along the front across IA
into MO. CAMs still bring storms to all sites later tonight and a
little after midnight. Tried timing storms at each sites for later
tonight and then have them on site only for a 2hr period. Some
showers could linger for a couple of hours at each site as well.
Clouds will be VFR to start and when the precip moves in, but
guidance suggests MVFR clouds will move in late tonight and last
until the mid morning hours. Thinking 2.5kft is where it will form
at, but some models show as low as 1.5kft. Scattered VFR clouds
are expected my mid morning at all sites. Winds will be southwest
with gusts over 20kts this evening and when the storms arrive.
After the storms and showers, winds will become northwest through
the rest of the TAF period. Speeds late tonight and tomorrow will
be around 10kts.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Nashville TN
855 PM CDT Sat Jun 22 2024
...New UPDATE...
.UPDATE...
Issued at 844 PM CDT Sat Jun 22 2024
It`s still very warm out there right now with the highest temp
sitting at 88 over BNA. Temperatures will only get down into the
mid to upper 70s overnight. For Sunday, models still show a small
disturbance moving through the area during the afternoon and
evening, but shower and thunderstorm chances remain low, between
25-35%. Latest models show we`ll be unstable enough for some
thunderstorms to develop, but lapse rates continue to be on the
low side, thus limiting any widespread severe activity tomorrow.
Nonetheless, any storms that do develop could produce gusty winds
and very heavy rain. Outside of the rain and storm chances,
another above-normal hot day is in store with highs reaching into
the mid to upper 90s for most across the mid state.
&&
.SHORT TERM...
(Rest of today through Sunday Night)
Issued at 1131 AM CDT Sat Jun 22 2024
Hot and humid is the main weather story today and tomorrow thanks
to an upper level ridge of high pressure overhead. Current
temperatures late this morning are already in the mid 80s on the
Plateau and upper 80s to low 90s elsewhere, and highs should
easily reach around 90 on the Plateau and mid to upper 90s across
the rest of the area this afternoon. Guidance such as the HRRR
continues to show some isolated showers and maybe a thunderstorm
popping up this afternoon, and indeed already seeing some tiny
showers on radar as well as some towering cumulus on visible
satellite. Therefore will keep a slight chance pop going, mainly
across our northeast half.
On Sunday into Sunday night, a weak cold front will move across
the area bringing a better albeit still low chance for showers
and storms across the midstate. Despite the increased rain
chances, temps will still be quite hot and near or only slightly
below today`s readings. SPC continues to highlight our cwa in a
marginal risk for severe storms on Sunday into Sunday night.
Forecast soundings do show MLCAPE peaking in the 1500-2000 range
on Sunday afternoon, but lapse rates are very poor in the 5-6C/km
range and shear is quite weak. Therefore not anticipating much in
the way of strong to severe activity, with a couple storms
potentially producing some strong microburst winds.
&&
.LONG TERM...
(Monday through next Saturday)
Issued at 1131 AM CDT Sat Jun 22 2024
Airmass behind the front will dry us out for Monday and Tuesday,
which will actually allow temperatures to heat up more easily
thanks to the upper ridge remaining nearby. Highs should reach the
90s both days areawide, and a few locations could hit the 100
degree mark such as BNA. Thankfully, lower dewpoints should keep
our heat index values just below the 105 degree mark for a Heat
Advisory both days, but it will be close.
Temperatures "cool" down for Wednesday and Thursday as an upper
trough digs southward from the Great Lakes pushing another front
down from the north. This system looks to bring our highest chance
for rain in the next 7 days on Wednesday, with high chance to
likely pops across the midstate. Forecast soundings show slightly
lower CAPE but a bit higher lapse rates and shear on Wednesday, so
a few strong or maybe severe storms could occur and another SPC
marginal risk is possible. After the brief respite from the heat,
a new and stronger upper ridge is forecast to develop across the
southern Plains eastward into the Tennessee Valley by next
weekend. Therefore we will heat right back up into the upper 90s
to near 100 by end of the forecast period, with only slight
chances for some summertime pulse showers/storms.
&&
.AVIATION...
(00Z TAFS)
Issued at 618 PM CDT Sat Jun 22 2024
VFR conditions are expected into tomorrow. We could maybe see a
little bit of patchy fog in fog prone areas between 07-11z and
that may bring a short period of MVFR conditions but confidence is
low. SCT to BKN clouds 040-060 tomorrow. Scattered showers and
thunderstorms will be possible starting in the northwest after
19z continuing to spread east into the afternoon. Light winds
tonight increasing out of the southwest after 15z becoming 10-15
knots gusting to 20 knots.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 74 96 74 96 / 0 30 10 0
Clarksville 73 92 70 93 / 0 30 10 0
Crossville 67 88 66 87 / 0 30 30 0
Columbia 71 96 72 97 / 0 30 20 0
Cookeville 69 90 68 89 / 0 30 30 0
Jamestown 69 88 68 86 / 0 30 30 0
Lawrenceburg 71 94 71 95 / 0 20 20 0
Murfreesboro 71 97 71 96 / 0 30 30 0
Waverly 72 93 70 95 / 0 30 10 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Baggett
SHORT TERM...Shamburger
LONG TERM....Shamburger
AVIATION.....Mueller
Area Forecast Discussion
National Weather Service Las Vegas NV
705 PM PDT Sat Jun 22 2024
.SYNOPSIS...Temperatures will continue to run around 5 to 8 degrees
hotter than normal through at least the middle of next week.
Moisture will continue to gradually push into Mohave County this
afternoon before spreading into San Bernardino and Clark Counties
overnight. Isolated showers and thunderstorms will be possible
tomorrow afternoon for portions of our forecast area south and east
of the I-15 corridor. This moisture will begin its slow retreat back
east on Monday with afternoon showers and thunderstorms remaining
possible for portions of Mohave County through the middle of the
week.
&&
.UPDATE...Convection today was limited to Mohave County and
generally short-lived. The only exception to this was a storm that
continued to redevelop over the Peacock Mountains east of Kingman,
producing nearly 1" of rain at a guage in the area. The only
remaining convection in our CWA is a few showers in far
eastern/southeastern Mohave County, along the leading edge of an
outflow boundary propagating out of Yavapai County. Any additional
development along the boundary should remain pretty weak and
transient as we continue to lose surface heating. Additional
moisture advection tonight will set the stage for better
shower/storm coverage tomorrow, primarily along and southeast of I-
15, but may extend up into eastern Lincoln County as well. Main
concerns will be gusty outflow winds and lightning, but like today,
cannot rule out an isolated flash flood threat if cells train over
the same area. Monsoonal moisture remains in place through mid-week,
keeping precip chances around for the aforementioned areas until a
trough brings drier and slightly cooler air in. Temperatures remain
above normal through the forecast period.
.SHORT TERM...through Monday.
Mid-level moisture continues its slow crawl north as is evident by
the dewpoint temperatures in the upper 50s in southeastern Mohave
County. When you take this moisture and combine it with intense
daytime heating and hotter than normal temperatures, you get an
increased chance for isolated showers and thunderstorms in Mohave
County this afternoon. Even with this moisture increase the lower
levels of the atmosphere remain relatively dry, which will make it
difficult for precipitation to reach the ground. While this drier
air near the surface may make it difficult for rain to reach the
ground, it will provide a favorable environment for gusty outflow
winds with any convection that does develop.
This moisture will continue to push into the southern and eastern
portions of our forecast area during the overnight hours, which will
bring increased chances for isolated showers and thunderstorms for
areas south and east of the I-15 corridor tomorrow afternoon. The
past few runs of the HREF and the latest run of the HRRR have shown
an uptick in the potential for isolated convective activity in
eastern Lincoln County tomorrow afternoon. While this is a slight
change from previous iterations of the forecast, it is not entirely
surprising as we tend to see convective activity in this region
during the North American Monsoon if the moisture makes it that far
north. The primary threats with any storms that develop tomorrow
will be periods of moderate rain, lightning, and gusty outflow
winds. Since this is the first time some portions of our forecast
area will have seen precipitation in quite a while, roadways may
become slick as oil and dirt are lifted from the surface.
By Monday the moisture will have begun it`s slow retreat back to the
east with lingering precipitation chances for southern San
Bernardino County and eastern Mohave County during the afternoon.
.LONG TERM...Tuesday through Friday.
An extended period of hot weather is the main story though much of
the week as an expansive area of high pressure sets up and holds
across the Desert Southwest as is typical for this time of year.
There are indications the high flattens a little Thu-Fri in response
to a trough swinging across the Intermountain Region. The latest
NBM indicates daily high temperatures across the Mojave Desert
zones will generally be in the 108-112 degree range which is
several degrees above normal...but not uncommon for late June. The
official forecast for Las Vegas holds at 108-109 for most days
except peaks at 110 on Wednesday. Overnight lows will be in the
mid to upper 80s. While this is hot, the latest HeatRisk grids
have backed off slightly on indicating areas of major HeatRisk
(level 3) for Tue-Wed and mainly keep moderate across most of the
region.
&&
.AVIATION...For Harry Reid...Winds will transition this afternoon
from light easterly to southeasterly to southerly with gusts of 15
to 20 knots, becoming light south southwesterly around sunset.
Sunday is likely to be more difficult, as scattered thunderstorms
primarily south and east of the terminal could produce outflow
boundaries which disrupt the winds. In the absence of outflows, a
similar transition as today from easterly to southerly would be the
most probable outcome.
For the rest of southern Nevada, northwest Arizona and southeast
California...Southerly winds gusting 15 to 25 knots are expected
over much of the region this afternoon, weakening overnight. Sunday,
scattered thunderstorms are expected primarily along and southeast
of Interstate 15, likely producing outflows which will disrupt the
winds and possibly causing poor visibility in blowing dust. These
storms will also produce isolated ceilings below 8000 feet with
associated terrain obscuration. Farther northwest, expect similar
winds as today, southerly gusting 15 to 25 knots.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Woods
SHORT TERM...Stessman
LONG TERM...Adair
AVIATION...Morgan
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