Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/23/22
Area Forecast Discussion
National Weather Service La Crosse WI
1053 PM CDT Mon Aug 22 2022
.DISCUSSION...(This evening through Monday)
Issued at 248 PM CDT Mon Aug 22 2022
Key Messages:
- Fog potential Tuesday/Wednesday morning
- Precipitation chances this week and this weekend
- Seasonable temperatures...with cooler readings behind the
front for Thursday/Friday and again Sunday
High pressure dominates the forecast through Tuesday with deep light
winds (<10 kts) to about 12kft for most of the night per RAP
soundings. With the potential for clearing skies, this brings the
question of fog into the forecast. One shortwave trough approaching
Fargo at mid-levels is providing a bit of cloud ahead of it,
however, most of this is mid-high level per GOES imagery and surface
observations. Will be watching this area for further cloud
development that will affect the evening cooling rates. There also
seems to be some signal for cooling just below the inversion again
near ~800 mb, which would favor a developing 5-7kft cloud layer
overnight - much like last night - and decrease fog potential.
22.12Z HREF has almost no fog signal tonight with some cloud
possible SW of La Crosse. Local hourly MOS LAMP trends at KLSE have
been moving away from fog over the last several hours. So, mixed
signals. For now have included patchy fog, but the potential remains
for at least river valley fog and possibly more coverage than
patchy. Future observational trends will be key to improving the
forecast for morning overnight.
Tuesday, a shortwave trough will be passing across the forecast
area. There is a return of mid-level moisture, especially across
portions of the western and southwest portions of the forecast
area within the warm advection and frontogenetic areas of the
shortwave. With convective temperatures in the upper 70s and highs
forecast in the upper 70s to lower 80s...should see some cumulus
develop and may see some showers/storms pop up with the
combination of the shortwave and heating. The CAMs are mostly dry,
however the WRFARW/NamNest have a few spotty showers Tuesday
afternoon/evening. Recent timing on the 22.12Z NAM is a little
quicker, thus the wave may be east of the area by peak heating.
For now will maintain some low pops in the chimney area.
We remain in northwest flow Tuesday night through Friday morning.
Weak shortwave trough energy over SD/Neb and a stronger shortwave
trough rotating through the Upper Mississippi Valley and Great Lakes
from Canada/Pacific NW will provide increased rain chances for parts
of the area Wednesday through Thursday. There are some important
timing, strength, and placement differences that will need to be
resolved to hone in on even higher pops though.
Tuesday into Wednesday...850mb warm air advection increases
across MN/NE. The 900mb winds are in the 20 to 35kts range, so
cannot rule out a few showers or isolated storms with the weak
forcing, theta-e advection, weak instability of 250-500 J/kg, and
steep mid level lapse rates. For now have isolated pops in the
chimney area during the afternoon and early evening and across
parts of SE MN and NE IA by Wednesday morning. We do have some fog
mention with the dewpoints depressions remaining low Wednesday
morning. Some of the models bring the rain chances farther east
toward the Mississippi River overnight. This would impact the fog
potential. For now have some rain chances and low QPF amounts, but
this will need to be assessed with future forecasts.
With the approaching shortwave, vorticity advection should see
showers and storms Wednesday afternoon into Thursday morning.
Instability increases Wednesday afternoon 1000-2000 J/kg with MUCAPE
of 2000-5000 J/kg from the NAM, deep layer shear of 35 to 40kts and
precipitable water values ahead of the cold front in the 1.5-2"
range. If this materializes, it would increase the severe weather
risk/risk for heavy rain. The 22.12Z HREF is mainly dry with a
few showers over parts of southeast MN/northeast IA Wednesday
morning. Showers and thunderstorms linger into Wednesday afternoon
through Thursday morning with continued cool air aloft, periods
of vorticity advection in the northwest flow. The models do not
agree on the coverage with the wave and the frontal passage. The
22.12Z Euro is more favorable across the local area, where with
the GFS/NAM, the coverage it greater to the north and toward GRB`s
area. The models are having trough resolving how the wave over
Saskatchewan and energy from the closed low in the northwest
evolve with the larger trough over Hudson Bay. For now, we have
some spotty pops in there with the higher likely pops Wednesday
night with the passage of the cold front. The moisture does not
clean out until Thursday night, thus...an isolated shower could
still pop up Thursday afternoon.
Temperatures should be seasonable with highs in the 70s to lower
(mid 80s for LSE) 80s Tuesday and Wednesday, with cooler 70s
Thursday.
The Friday through Sunday forecast will need to be watched as the
GFS has shortwave trough energy farther south compared to the EC and
is wetter. Our Friday forecast is currently dry with highs in the
70s. The chance for rain gradually works east through the weekend
with warm...moist south low level flow ahead of the trough. Again
the GFS is faster with a drier EC until Saturday night and Sunday
when the trough passes through. Seasonable highs in the 70s to lower
80s are forecast, but will be impacted by any extensive cloud cover
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1053 PM CDT Mon Aug 22 2022
Another night and the same concerns for valley fog. With an area
of high pressure over the region, a deep light wind layer is in
place and will remain through the night. The surface winds have
already become light southeast for an up channel flow. The
temp/dew point spread tonight is a touch wider than this time
Sunday evening, but still favorable for fog formation. And
similar to Sunday evening, there are some clouds drifting across
the area that could disrupt the fog formation. The 23.00Z NAM
shows saturation occurring at the surface while the RAP runs this
evening do not. However, unlike last night, the office skycam
shows a haze layer looks to be forming over the valley already.
Will be a bit more aggressive that previous forecasts in taking
the visibility down at KLSE but hold it at 1 mile for now given
the concerns about clouds. Outside of the fog concerns, VFR
conditions are expected through Tuesday evening.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Baumgardt/Zapotocny
AVIATION...04
Area Forecast Discussion
National Weather Service Cheyenne WY
527 PM MDT Mon Aug 22 2022
.SHORT TERM...(This evening through Tuesday)
Issued at 259 PM MDT Mon Aug 22 2022
A decent cumulus field has developed across southeast Wyoming and
the Nebraska panhandle this afternoon due to afternoon heating and
decent lapse rates at the surface. However, once the air gets to
mid-levels, due to the intensely dry air and warm layer, no
substantial convection is expected. An isolated storm or two is
not out of question, but once the sun sets the primary forcing
will be shut off. So, if there is going to be a
shower/thunderstorm it will have to happen between now and 8 PM
MDT. The most likely area for this shower/thunderstorm will be
near the Wyoming/Colorado border developing in the Snowy Range
and/or South Laramie Range. Another thunderstorm opportunity is in
far northeast Dawes county of the Nebraska panhandle. There are
storms developing along the Wyoming/South Dakota border and if one
of those thunderstorms tracks southeast, it would clip Dawes
county. Overnight tonight we should see clearing skies and dry
air, so minimum temperatures were dropped overnight due to
radiative cooling. Expect low temperatures in in the upper 40s to
50s.
Tomorrow, Tuesday, there are increased chances of precipitation,
primarily along and just east of the Laramie Range, Converse and
Niobrara counties, and the northern Nebraska panhandle. The HRRR
is the most robust solution currently showing widespread
development across Converse, Niobrara, Sioux, and Dawes counties
and a line of thunderstorms developing on the Laramie Range and
moving southeast across southeast Wyoming and the central/southern
Nebraska panhandle. The CAPE and shear values are not impressive,
so the likelihood of that line developing is low, but not
conducive to that style of convection in far southeast Wyoming and
the southern Nebraska panhandle. Up in Converse, Niobrara, Sioux,
and Dawes counties though, there are MUCAPE values 600 to 1200
J/kg, however with shear values only 10 to 15 knots. Based on
this, there will likely be thunderstorms, but they will not be
very strong or long-lasting. Convection will likely end between 9
PM MDT and midnight.
.LONG TERM...(Wednesday through Monday)
Issued at 209 PM MDT Mon Aug 22 2022
Overall, the long term forecast looks to contain near-normal to
slightly above-normal temperatures for late August, primarily in the
80s, with multiple chances for showers and thunderstorms. The upper
level ridge over the Intermountain-West will remain in place mid-
week before shortwaves begin to pass through in the flow. A backdoor
cold front sliding south could be the focus for precipitation
Wednesday afternoon over east-central Wyoming, while convection in
the higher terrain will be possible. This front looks to linger
around into Thursday with southeasterly flow drawing up moisture and
PWs increase to near 1" along the Pine Ridge area. Latest NAM is a
little farther south with the moisture while the GFS keeps mid-50
dew points in southwest SD. Regardless, increased flow with the
passing shortwave will increase shear values to around 30 kt leading
to the potential for a few strong storms from east-central WY and
points east.
Chances of showers and storms will continue across the CWA Friday
and into the weekend as the ridge breaks down and more zonal flow
with disturbances passing through the area. 700mb temps look to
remain fairly consistent into the weekend. By late in the weekend,
GFS and EC both have a progressive shortwave passing across MT.
This could lead to a brief period of strong winds with a frontal
passage, however little consistency is present among ensemble
members at this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 524 PM MDT Mon Aug 22 2022
VFR conditions expected for the forecast period. The possibility
exists for a very isolated storm to produce lightning in the
vicinity of each terminal for the next hour or two. Light winds
overnight, but gusts of 15 to 20 knots possible again on Tuesday
afternoon.
&&
.FIRE WEATHER...
Issued at 209 PM MDT Mon Aug 22 2022
Drier air has moved into most of southeast Wyoming and the
Nebraska panhandle and will continue to dry out into tomorrow
afternoon. Isolated to scattered chances for showers and
thunderstorms Tuesday. In areas that have not received much recent
moisture, lightning strikes could start fires as these showers and
thunderstorms will not produce much precipitation. Increased
scattered to widespread shower/thunderstorm chances Thursday and
Friday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...LK
LONG TERM...MB
AVIATION...MN
FIRE WEATHER...LK
Area Forecast Discussion
National Weather Service Green Bay WI
1035 PM CDT Mon Aug 22 2022
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Tuesday
Issued at 214 PM CDT Mon Aug 22 2022
The latest RAP analysis and satellite/radar imagery show a large
high pressure system centered across the western Great Lakes to
the central Mississippi Valley. Diurnal cu has become more
widespread than guidance suggested previously, but a dry airmass
with pwats 60 to 80% of normal remains centered across northeast
WI and has kept the cu behaved. Weak shortwave energy is sliding
southeast across the Dakotas and south-central Canada with a cold
front dropping into far southern Canada. Very few returns exist
upstream as moisture runs into this drier airmass. Forecast
concerns revolve around a repeat of patchy dense fog tonight,
followed by thunderstorm chances tomorrow as the front moves into
northern WI.
Tonight...Weak shortwave energy will pass across the region
tonight. While diurnal cumulus will dissipate early in the evening,
the shortwaves will bring in scattered mid and high clouds at
times, which will lower fog potential somewhat. Still though,
guidance continues to show however visibilities over central,
north- central, and far northeast Wisconsin after midnight, so the
chance of patchy ground fog will remain in the forecast. Warmer
lows in the lower 50s to near 60.
Tuesday...Weak shortwave energy passing across the northern Great
lakes will push an equally weak front into northern Wisconsin in
the afternoon. After a mostly sunny start to the day, will again
see fair weather convective clouds develop with heating. Mixed
layer instability could reach up to 1000 j/kg across far northern
WI in vicinity of the front during the afternoon. Convergence
isn`t really strong and mid-level lapse rates less than 6 C/km are
poor, so the threat of severe weather will remain low. But a few
showers and storms will be possible. High temps in the low to mid
80s.
.LONG TERM...Tuesday Night Through Monday
Issued at 214 PM CDT Mon Aug 22 2022
Mean flow at the start of the period to consist of an eastern
Pacific upper ridge, a weak closed upper low over the Pacific
Northwest and a stronger closed upper low over Hudson Bay. This
set-up keeps a northwest flow aloft into WI into Friday with weak
disturbances bringing chance pops to northeast WI. By next
weekend, the Hudson Bay low lifts farther northeast, a new
shortwave trough moves into the northern Plains and the upper
ridge shifts farther west into the Pacific. Precipitation chances
look to return for the latter half of the weekend. Temperatures
for the most part will be above normal.
Tuesday night and Wednesday...
Even as instability wanes and a weak mid-level shortwave departs
Tuesday evening, a weak frontal boundary will remain draped over
northern sections of the Great Lakes Tuesday night. Therefore,
will need to carry a small chance pop mainly north of Hwy 8.
Otherwise, central and east-central WI to see mostly clear to
partly cloudy skies with patchy fog again possible as dew points
to still be in the lower half of the 60s and winds become light/
variable. Min temperatures to range from the middle to upper 50s
north, lower 60s east-central WI. Models continue to show this
weak frontal boundary to slowly sag south and reach central/
east-central WI by 00Z Thursday. While the wind field and shear
are forecast to be weak, models do show another mid-level
shortwave tor be moving through the area. Instability is marginal
(around 500 J/KG), but enough to bring a few storms to northeast
WI. Highest pops to be placed over northern WI as the boundary
drops through, mainly during the afternoon. Max temperatures to be
in the middle to upper 70s north, upper 70s to lower 80s south.
Wednesday night and Thursday...
Precipitation chances to persist into Wednesday night with the
better focus over the southern half of WI as the boundary shifts
into southern WI. The main unknown will be where a weak surface
wave will move along the boundary to provide additional lift.
One set of models bring this surface wave into central WI, while
another set of models favor a track into southern WI. Locally
heavy rain may occur wherever the surface wave traverses, so we
will need to watch this over the next couple of days. Min
temperatures to be in the middle to upper 50s north, mainly lower
60s south. Even though the surface boundary sags into far northern
IL on Thursday, a cyclonic flow around the Hudson Bay upper low,
the passage of yet another shortwave trough and daytime heating
will combine to keep a chance of showers/thunderstorms in the
forecast through most of Thursday. Max temperatures to be in the
lower 70s north, middle to upper 70s south.
Thursday night and Friday...
Improving conditions are expected Thursday night due to the loss
of daytime heating, the exit of the shortwave trough and an
eastward shift of the upper low. High pressure to build into the
Great Lakes region later Thursday night into Friday thus dry
conditions to return with a good amount of sunshine on Friday.
Max temperatures to be in the lower to middle 70s north/near Lake
MI, middle to upper 70s inland.
Friday night and Saturday...
Quiet conditions to persist through Friday night as the high
pressure begins to shift east into the eastern Great Lakes. For
the most part, the bulk of Saturday looks to be dry as our next
weather system to be over the northern Plains. That being said, a
stray shower or two cannot be ruled out along any lake breeze
boundary that may develop by early afternoon. A return flow into
WI will usher in a warmer, more moist atmosphere with max
temperatures on Saturday in the middle 70s north-central WI/near
Lake MI, upper 70s to around 80 degrees elsewhere.
Saturday night through Monday...
Forecast confidence takes a hit for the end of the weekend into
early next week primarily due to model inconsistency with the
movement of a shortwave trough/associated cold front. Faster
models would bring precipitation chances into parts of northeast
WI as early as Saturday afternoon, whereas slower models would
keep eastern WI dry through Sunday. Besides the timing issues,
there is also the possibility of stronger storms Sunday afternoon
if the slower solution is correct and we can destabilize enough
ahead of the system. For now, have followed the consensus solution
which brings the highest chances for precipitation Sunday
afternoon into Sunday night. Max temperatures for both Sunday and
Monday to be in the upper 70s to lower 80s.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1030 PM CDT Mon Aug 22 2022
The potential for widespread fog is much lower than last
night/early this morning, and will again refrain from having any
mention of fog in the prevailing conditions overnight. The main
aviation weather concern has shifted to the potential for
SHRA/TSRA across the north tomorrow. Coverage will be scattered.
Will introduce the precip with a mention of SHRA at KRHI during
the late aftn/eve.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kallas
AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Jackson MS
959 PM CDT Mon Aug 22 2022
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
There is somewhat of a lull in the heavy rain threat as expected,
but unseasonable low to mid level cyclonic flow associated with a
low pressure center in the ArkLaTex region will interact with
anomalous tropical like moisture (e.g., H850 Td near 16 deg C, PW
> 2.3", deep warm cloud layer) to bring a return of widespread
shower/tstm activity with highly efficient rainfall rates as we
go into the predawn to early morning hours Tuesday. Most guidance
suggest NE LA will be the primary concern initially, but
confidence is somewhat low concerning the mesoscale influences.
Will be monitoring for the potential for a more significant FF
threat to develop given high soil moisture content and keep the
flash flood watch going as is. /EC/
Prior discussion below:
Tonight and tomorrow....
The weather for the next 24 hours can be summed up in one word:
rain. The area has been seeing more or less widespread rain today,
with some locations clearing this afternoon, but there remains
plenty more rain to our west. South of I-20, where there has been a
bit more instability, more in the way of thunderstorms have occurred
this afternoon. Some storms have become strong with wind gusts being
the primary concern. This will continue through the afternoon and
into this evening.
There may be a brief lull in convection overnight, or some decrease
in the coverage. This should increase once again tomorrow. This all
is in conjunction with a stalled boundary to our north, and a
surface low that is moving out of Texas. As this low moves to the
north and east, additional showers and isolated thunderstorms will
continue to move across the Mid-South to Lower Mississippi River
Valley region, especially tomorrow into Wednesday. Given the PW
values of around 2.23 inches present and expected to continue across
the region, efficient rainfall will continue across the region.
This will lead to flooding concerns. The highest rainfall totals
looks to be in southeast Arkansas, northeast Louisiana and
portions of west, northwest and central Mississippi. Here, a
flood watch has been previously issued and continues through
Tuesday evening. The area was expanded a little bit based on the
latest runs of some recent CAM models and it is likely that it
will needed to be extended in time longer. Storm total QPF through
Wednesday shows widespread 1-2 inches of rain with a large area
of 3-4 inches across the flood watch area, and locally higher
totals of around 5 to 7 inches along and west of the MS River. We
have also expanded the elevated flooding area on our local impact
graphics to match this area, with some monitoring for a possible
need for a Significant in future forecasts.
Thanks to the widespread cloud cover and rainfall, this has allowed
temperatures to be kept in check. Highs tomorrow should be generally
in the 70s and maybe a few spots are able to reach the lower 80s.
/28/
Tuesday night into Wednesday night: Though a decrease in areal
coverage of rain is anticipated heading into Tuesday night with the
loss of diurnal heating, one or two more concentrated corridors of
heavier rain will remain possible throughout the overnight given the
persisting moisture-rich environment and a remnant surface low.
Recent runs of the Euro and the 12z HRRR are hinting at this, though
in slightly different areas. To our west we`ve already just seen how
high the potential ceiling is for nighttime flash flooding with this
system and similar impacts are possible...locally...in our region as
well. Though the current flood watch only runs through early Tuesday
evening, there`s a decent chance it will need to be extended into
Tuesday night, especially once we are able to hone in on where the
heavier rain bands are most likely to set up. Of course, this rain
will be filtering into local waterways, so river flooding will be an
increasing concern through the week as well. The heavy rain threat
becomes more uncertain Wednesday into Wednesday night as somewhat
drier air nudges in from the northeast, though rain chances will
remain high and localized flooding still can`t be ruled out.
Thursday through next Monday: As the broad upper troughing builds
slightly further southward, we`ll see a modest decrease in deep
layer moisture through the remainder of the forecast period. While
rain chances will remain above average for late August, convection
should again become more diurnal in nature. /DL/
&&
.AVIATION...
00Z TAF discussion:
Poor aviation weather with considerable LIFR/IFR ceilings and
occasionally reduced vsbys will be the general rule through the
forecast period. The greater chance for +RA/TSRA should be
developing from west to east from late tonight into Tuesday.
Expect surface wind to be light. /EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 71 77 70 80 / 68 93 72 88
Meridian 70 77 70 81 / 77 88 67 84
Vicksburg 72 77 71 80 / 84 84 67 83
Hattiesburg 72 79 71 82 / 47 90 65 90
Natchez 71 77 71 80 / 74 91 68 88
Greenville 71 77 70 80 / 90 88 50 72
Greenwood 70 79 69 82 / 78 83 54 76
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Flood Watch through Tuesday evening for MSZ018-019-034>037-
040>044-047>050-053>056-059>063.
LA...Flood Watch through Tuesday evening for LAZ007>009-015-016-
023>026.
AR...Flood Watch through Tuesday evening for ARZ074-075.
&&
$$
Area Forecast Discussion
National Weather Service North Platte NE
540 PM CDT Mon Aug 22 2022
.SHORT TERM...(This evening through Tuesday night)
Issued at 337 PM CDT Mon Aug 22 2022
The main forecast challenges through midweek revolve around
thunderstorm chances and continued summertime temperatures. A couple
surface boundaries and a mid-level wave passage present isolated to
scattered thunderstorm chances this evening and again tomorrow.
Somewhat stronger systems toward the end of the week present more
widespread precipitation potential, along with slightly cooler
temperatures.
This evening and tonight... A subtle surface boundary stretches
across the panhandle, which may be a focus for isolated
thunderstorms. Dry air has resulted in very steep lapse rates near
the surface and fairly steep (7-8 C/km) in the mid levels. Some CAMS
solutions, including the HRRR, suggests a few cells initiating
before 00z and dissipating by 03z. Conditions don`t appear overly
great for activity as surface dew points have been dropping through
the afternoon. However, a couple storms managed to develop yesterday
under the same conditions. Introduced schc (20%) PoP in the
panhandle and western Sandhills near the boundary. Otherwise, partly
to mostly clear conditions are expected overnight with fairly mild
lows in the mid/upper 50s southwest and lower/mid 60s north central.
Tuesday... The heart of the main upper ridge that covers much of
the Western US retreats slightly toward the Desert Southwest.
Nebraska has enough influence from the ridge to keep summertime
conditions around, especially with persistent south/southwest flow
at H85. Weak WAA is in play with temps approaching or surpassing
25C. A weak shortwave brushes north central Neb during the morning,
which may provide enough forcing to support a few brief rain showers
or embedded thunder. Later in the day, a surface low slides across
South Dakota, which presents a greater chance for precipitation for
the northern half of the CWA. The low and attendant surface trough
will take advantage of steep low and mid level lapse rates and
slightly better moisture than today. Severe parameters are low
however, as MUCAPE maxes out around 500 j/kg and deep layer shear of
only 15 to 20 kts. Used a blend of HREF and HRRR for general precip
coverage and timing. Expect most (if not, all) activity to wane by
midnight as forcing and instability decrease. For max temps, the
guidance envelope is fairly small and centered around the lower/mid
90s. Felt no need to push temps any higher given increasing
cloudiness and precip chances during the afternoon and peak heating
period. There`s also the chance for the far northern CWA to
transition to northerly flow in the vicinity of the surface low.
Tuesday night lows should be similar to tonight`s, perhaps a degree
or two cooler in the wake of thunderstorms.
.LONG TERM...(Wednesday through Monday)
Issued at 337 PM CDT Mon Aug 22 2022
Wednesday and beyond... The upper ridge breaks down and is replaced
by a progressive trough over the northern Plains, partially driven
by a closed low riding the international border. Closer to the
surface, a series of boundaries cross the forecast area, including a
cool front late Wednesday and a warm front late Friday. Each of
these will promote additional shower and thunderstorm development.
An early look at severe potential appears mixed with bouts of decent
instability and shear, but the best ingredients are somewhat
localized. Temperature-wise, seasonably warm highs near 90F continue
Wednesday, then dip into the 80s to round out the week with a little
rebound later in the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 540 PM CDT Mon Aug 22 2022
Expecting VFR conditions to prevail across central and western
Nebraska through this valid period.
Current scattered field of cumulus may result in an isolated,
brief shower/thunderstorm early this evening but do not expect any
impacts in the vicinity of either KLBF or KVTN. Toward the end of
the valid period expect some scattered showers/thunderstorms will
develop along the NE/SD border and sink southward, but not make
much progress past highway 2. Will include VCTS at KVTN with a
VFR CIG toward the end of the valid period, but maintain dry
conditions at KLBF.
The low level wind field will amplify early tonight and there are
indications that the boundary layer will remain mixed enough to
support an occasional wind gust at KVTN. Will indicate this in the
TAF but expect any gusts will be quite sporadic. There may be a
few gusts Tuesday morning once better mixing becomes established
after sunrise but overall do not expect winds to have a
significant impact to aircraft operations through Tuesday evening.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Snively
LONG TERM...Snively
AVIATION...MBS
Area Forecast Discussion
National Weather Service Spokane WA
322 PM PDT Mon Aug 22 2022
.SYNOPSIS...
The weather this week will feature several chances for showers and
thunderstorms. While much of the Inland Northwest probably won`t
get much rain this week, a few spots could get a lot of rain
quickly under slow moving thunderstorms. In general, temperatures
won`t be as hot as they have been the last couple of weeks. High
will mainly be in the upper 80s to lower 90s.
&&
.DISCUSSION...
Tonight: Slow moving thunderstorms capable of locally heavy rain
will be our primary concern for the remainder of the afternoon
into early this evening. Central Washington has experienced
sunshine for the majority of the day pushing temperatures well
into the 90s in places like Omak, Wenatchee, Grand Coulee and
Moses Lake. Afternoon heating has contributed to destabilization
over the high terrain of north central Washington where surface
based CAPE values the RAP analysis is in the neighborhood of
400-800 J/Kg over the steep terrain of Okanogan county. With
700-500mb flow of 15kts or less, thunderstorms have moved very
little since developing shortly after 1 PM. While burn scars are
the most vulnerable to flash flooding, the rain rates that we have
seen so far with these storms (1.5 to 2.0 inches per hour) have
the potential to produce flash flooding outside of burn areas as
well. Small hail and frequent cloud to ground lightning will also
accompany the strongest cells through early evening.
The Red Flag Warnings for lightning across southeast Washington
and northeast Oregon will be cancelled this afternoon. Some
additional showers and a few lightning strikes may occur over the
Blue Mountains into the southern Idaho Panhandle through early
evening, but this area has been worked over today with
precipitation earlier in the day and may not recover.
Low temperatures tonight will be cooler across most of the region
than they have been over the last 4 or 5 days. Clearing skies
overnight will allow temperatures to fall into the 50s and 60s.
Places like Wenatchee and Lewiston haven`t fallen below 70 in the
last 3 or 4 nights...which is well above average.
Tuesday: It will be another warm day Tuesday with highs in the
upper 80s and lower 90s across most of the Inland Northwest. A few
spots like Omak, Grand Coulee and Lewiston will likely reach mid
90s. We will be monitoring the radar along the Canadian border for
thunderstorm development in the afternoon. Similar to today,
widely scattered and slow moving thunderstorms will deliver very
heavy rain to a few spots while the majority of the Inland
Northwest will remain dry.
Wednesday and Thursday: A slow moving upper low will park over
central Washington Wednesday bringing the best chance for
scattered showers region-wide. The upper low will hedge
northeastward into far north Idaho on Thursday delivering the best
shot of thunderstorms to far north Idaho and extreme northeast
Washington. Again, a few places have the potential to get
drenched under slow moving thunderstorms. Flash flooding will be
possible both Wednesday and Thursday with precipitable water
values over an inch or more over Washington and north Idaho. The
low overhead combined with the high moisture content of the
atmosphere should take a couple degrees off our high temperatures
Wednesday and Thursday with mid 80s to low 90s both afternoons.
Friday and Saturday: As our slow moving upper low departs, Friday
and Saturday will become breezier. At this time, it looks like
sustained west winds of 10 to 15 mph with gusts to 25 mph will
occur across the Columbia Basin, Palouse, and West Plains both
days. Localized gusts of 30 to 35 mph will likely occur through
the Cascade gaps including places like Wenatchee, Vantage, Chelan,
and Waterville. Many places with gusty winds on Friday will
experience high temperatures in the 90s with low humidity, so
wildfire spread will be a concern on Friday. High temperatures on
Saturday will drop into the 80s, but gusty winds will remain a
concern across much of the Inland Northwest following 4 or 5 weeks
of hot and dry weather.
Sunday and Monday: There is a good deal of forecast uncertainty
early next week. At this time, it looks like seasonably warm
temperatures Sunday (80s) will trend hotter (upper 80s/low 90s)
by Monday. However, there is a lot of variability in the medium
range ensembles by days 6 and 7, so we may see some changes.
/GKoch
&&
.AVIATION...
00Z TAFs: VFR conditions will prevail. Diurnal winds will mostly
dominate the conditions at the TAF sites. Isolated convection
has the potential to bring brief erratic gusty winds to 30 mph to
GEG and SFF between 03 to 06Z Tuesday, but confidence is very low
in this solution. /db
/JDC
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 91 62 89 61 88 / 10 10 10 20 30 20
Coeur d`Alene 57 89 60 87 59 86 / 10 10 10 20 30 20
Pullman 54 87 55 89 54 86 / 10 0 0 20 10 10
Lewiston 65 95 66 96 66 94 / 10 0 0 10 10 10
Colville 51 92 51 88 51 88 / 10 20 10 20 30 20
Sandpoint 55 86 57 83 57 81 / 10 20 20 30 50 40
Kellogg 62 86 62 85 62 83 / 10 20 10 30 30 30
Moses Lake 60 95 64 95 63 94 / 0 10 10 10 10 10
Wenatchee 67 93 69 93 69 94 / 0 10 10 10 10 10
Omak 63 94 65 93 64 94 / 20 20 10 30 20 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Pocatello ID
836 PM MDT Mon Aug 22 2022
.SHORT TERM...Tonight - Tuesday. Afternoon satellite imagery
shows developing CU field across the high country of the central
mountains and eastern highlands this afternoon. These are the two
areas expected to see the best precip chances this afternoon and
evening. Upper trough in place across the Pacific NW should allow
for a bit more storm motion across the area today, especially
further north. Morning IMET sounding out of Salmon showed PWAT
values above 0.8 inches which was a bit higher than expected and
remains above model forecasts as current RAP analysis remains lower
than that. This may allow for a few some of the scattered storms
across the central mountains to be a bit wetter than expected this
time yesterday but nevertheless, some dry thunderstorms are also
possible and the Red Flag Warning continues into the late evening.
CAMs maintain highest PoPs across the high country but there is some
support for showers and storms making it into the Snake Plain and
portions of the Magic Valley. PoPs here will be much lower however
as convective activity will be quite isolated and more of the "hit
or miss" variety. As has been the case the past few days, gusty
winds and small hail will be a concern. Atmospheric looks to dry out
further as we move into Tuesday with PWs area-wide around half an
inch tomorrow. This should limit the convection potential tomorrow
with areas along the Montana Divide and the Wyoming border likely to
be the only places with precip potential and this would probably be
pretty isolated at best. Temperatures continue to run at or just
above climatological norms the next few days with light winds aside
from any thunderstorm outflow winds. McKaughan
.LONG TERM...Wednesday through next Monday. A semi-stationary
upper low will remain parked over eastern Washington Wednesday and
Thursday. Models indicate a lobe of monsoon moisture will work its
way into the region from the southwest on Wednesday aimed at the
South Central and Southeastern Highlands. There will be a good
chance for thunderstorms both Wednesday and Thursday afternoon given
the support from the upper trough and moisture advection from the
southwest. Operational models show the upper low will begin to move
to the east on Friday with drier westerly flow setting up over the
forecast area. Ensemble clusters and operational models offer some
uncertainty as we head into the weekend. Cluster mean on Saturday
shows mainly zonal flow, but half the clusters support upstream
ridging while the other half support upstream troughing. GFS is
showing some significant adjustments between the 06Z and 12Z runs as
the newer run is backing down on a deep trough approaching on
Saturday, but still more intense than the ECMWF or Canadian model.
Hinsberger
&&
.AVIATION...
VFR conditions expected to prevail outside of showers and
thunderstorms. Hi-res models continue to show the potential for
showers/storms to impact some of the terminals later today between
22-03Z especially. This is most likely at KSUN and KDIJ. Not
enough confidence however to include any TEMPOs at this time so
will continue to run with VCTS at these and the other eastern
Idaho terminals. Any activity should be over by midnight, if not a
bit sooner, allowing VFR to prevail through the overnight and
into the morning/early afternoon. Another round of
afternoon/evening showers will be possible across the high
country Tuesday, likely north of KSUN but may sneak into KDIJ
during the afternoon. Winds outside of any convection will be
light, generally 10 kts or less, but thunderstorm outflows could
cause locally higher winds for a brief period. McKaughan
&&
.FIRE WEATHER...Convective activity has begun to diminish rapidly
this evening and thus we have allowed the Red Flag warning to expire
for the remainder of this evening. Updated products will follow
shortly. See the previous discussion below. Huston
An upper trough is seen lifting through WA/OR today with morning
convection over the Columbia River Basin shifting eastward into
Northern Idaho. High-res models support convection expanding into
the Central Mountains around noon today, and the Southern and
Southeastern Highlands around mid-afternoon. Scattered thunderstorm
coverage is expected for fire zones 475 and 476 today, prompting the
Red Flag Warning. These storms today will be primarily dry, though
some localized wetting rains are possible. The other fire zones will
likely see isolated coverage today. The upper trough will remain
fairly stationary through Thursday, though drier air will be in
place for tomorrow. Tuesday may only bring some isolated afternoon
thunderstorm coverage to the Island Park area. Storm coverage will
be more expansive on Wednesday as a lobe of monsoon moisture works
into the area from the southwest. With higher PWATs in the south,
there`s a better chance of wetting rain over the Southeastern
Highlands. Storms over the Central Mountains on Wednesday and
Thursday look to be fairly dry with PWATs 0.5" or less. Models show
drier weather moving into the region on Friday with the upper trough
departing to the east. Hinsberger
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
825 PM EDT Mon Aug 22 2022
...New UPDATE, AVIATION, MARINE...
.UPDATE...
Issued at 820 PM EDT Mon Aug 22 2022
Convection took a little longer to get going this evening, but
finally starting firing off a couple of hours ago. The strongest of
these storms have been over the interior and southwest Florida with
the highest wind gusts around 30-40 mph. The latest HRRR guidance
move these storms slowly toward the coast over the next few hours
and then diminishing overnight. Made some slight tweaks to POPs
based on latest radar trend and models guidance. No other changes
needed at this time.
&&
.AVIATION...
(00Z TAFS)
Issued at 820 PM EDT Mon Aug 22 2022
Will hold VCTS at all terminals through 03Z and TEMPO TSRA at
PGD/FMY/RSW through 01Z. Outside of thunderstorms, VFR conditions
and winds 10 knots or less are expected to prevail through the
period.
&&
.MARINE...
Issued at 820 PM EDT Mon Aug 22 2022
High pressure remains over the area with light ENE through ESE winds
becoming westerly close to the coast each afternoon. Showers and
storms are expected along the coast and over the Gulf waters late
evening. Frequent lightning and strong wind gusts will be possible
near storms, so mariners should remain vigilant during the afternoon
and evening hours. Otherwise, no headlines are needed through the
period.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 80 93 80 93 / 40 60 30 70
FMY 78 94 78 94 / 60 60 40 70
GIF 78 95 77 95 / 60 80 30 80
SRQ 76 91 76 91 / 40 60 30 70
BKV 73 93 73 93 / 20 70 30 70
SPG 80 91 80 91 / 40 60 30 70
&&
Sea Breeze Thunderstorm Regime For Monday: 6
Sea Breeze Thunderstorm Regime For Tuesday: 1
For Additional Information On Sea Breeze Regimes go to
https://www.weather.gov/tbw/ThunderstormClimatology
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...Wynn
DECISION SUPPORT...Fleming