Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/12/24
Area Forecast Discussion
National Weather Service La Crosse WI
1003 PM CDT Tue Jun 11 2024
.KEY MESSAGES...
- Isolated thunderstorms possible this afternoon, some of which
could produce small hail and gusty winds.
- Complex severe weather setup for Wednesday afternoon and
evening with the potential for multiple rounds of storms.
Large hail, damaging winds, heavy rainfall and possibly a few
tornadoes are all on the table depending on how storms unfold.
- Warmer weather on the docket for early next week with highs
pushing into the upper 80s to low 90s from Sunday through
Tuesday.
&&
.UPDATE...
Issued at 1004 PM CDT Tue Jun 11 2024
Challenging forecast for tomorrow on synoptics and mesoscale
evolution and the severe storm threat.
Things are still on track with the thinking of a moisture surge
into western MN tonight with storms erupting in the pre-dawn
hours near the ND/MN/SD triple point. Moisture transport
convergence and the instability is really keying on this area in
the RAP and latest 12.00Z CAM solutions. We are still firmly
entrenched in the pacific air mass overhead right now with low
dewpoints and stable conditions. During the morning hours,
moisture transport in the low-levels and instability continues
to surge northeast across MN, but the rate is in question.
Based on the timing of the pre-dawn storms and their southeast
motion, the instability would seem to favor a more southerly
track, with storms propagating into the instability. All of the
12.00Z CAMS want to track some convective system toward the
area arriving by late morning, with questionable instability,
mainly elevated, but a ton of warm air and moisture advection
into the area. But still, as the complex moves southeast,
possibly some severe, it is outrunning instability. And this
timing could kill the afternoon severe weather chances by
limiting heating. The 12.00Z HRRR delays the complex just an
hour or two into the forecast area from the northwest and has
the strongest outcome of afternoon storms. I think that speaks
to the sensitivity of when these morning storms/showers arrive
and if they continue to develop into severe storms or not. Later
favors severe storms. The earlier arrival seems to favor a low
severe weather chance overall with heating and moisture
advection impacted. Either way, the first system seems to really
seems to really cap off and stabilize the atmosphere. The CAMS
also suggest generally that there is probably only one
morning/afternoon system/shot.
Overall, the new 12.00Z CAMS seem to produce fewer waves of
storms from 18-09Z overall. One pattern we need to watch for is
a NW->SE oriented boundary setting up west of a strong
convective complex and cold pool. The orientation of the low-
level flow and moisture advection into that boundary orientation
would favor a training scenario with storms moving southeast
along the boundary.
So, still details to workout. Will be working to increase the
later morning storm chances in southeast MN after 15Z per the
accelerated CAMS into that area. Soundings and instability arent
the greatest for severe weather that early (as stated above per
later HRRR).
&&
.DISCUSSION...
Issued at 250 PM CDT Tue Jun 11 2024
This Afternoon and Evening: Isolated Storms
Current radar mosaic this early afternoon shows this morning`s
showers continuing to exit eastward out of the local forecast area.
GOES satellite imagery and RAP progs show an upper level trough
continuing to move towards the region, with surface observations
showing an approaching (currently draped down through central MN)
surface cold front. As the front moves across the area, model
guidance continues to suggest the potential for isolated to widely
scattered showers and storms to develop this afternoon/evening.
However, there still remains some uncertainty in just how much
instability will be able to build ahead of the front.
Hi-res guidance would suggest the potential for a very narrow
axis of instability with CAPE values generally around/under 1000
J/kg. If storms do develop, stronger storms may be capable of
producing small to marginally severe hail and gusty winds.
However, as we lose daytime heating the storm threat will
quickly decrease. There is still quite a bit of variability in
solutions on location/timing of initiation of storms, so will be
monitoring near-term satellite and radar trends closely through
the afternoon and evening.
Wednesday Afternoon and Evening: Severe Weather Details
A zonal pattern becomes established for tomorrow with a
seasonable strong 120-kt jet working over the Dakotas in the
wake of subtle perturbation in the flow. The surface boundary
sliding southeastward this evening quickly washes out overnight
with southerly flow becoming reestablished up through Minnesota
by sunrise tomorrow. Steepening mid-level lapse rates and
increasing surface theta-e values result in SB/MLCAPE values
approaching 2000 J/kg by the mid-afternoon while elongated
hodograph will be supportive of organized storm structures.
The main question revolves around convective mode and timing.
The latest 12Z HREF members are rather locked in on having
elevated convection develop on the nose of a weak low-level jet
towards sunrise in western Minnesota, with this complex and its
convective debris/cold pool serving as the focus for renewed
development during the early afternoon hours in central/eastern
Minnesota and western Wisconsin. The hodographs would be
supportive of supercellular structures and all storm hazards,
though the explicit composite reflectivity progs show rapid
upscale growth along the line into an MCS that propagates SSE
with the Corfidi vectors during the afternoon.
However, with the main synoptic forcing still off to the west,
renewed development is likely along the western flank of this
MCS cold pool that would result in multiple rounds of
thunderstorms training over the same area throughout the late
afternoon and evening hours along a northwest to southeast axis.
This would point to a potential heavy rain and flooding threat
somewhere in south-central Minnesota to northeast Iowa, but it
remains too early to pin down the exact area as such a threat
will rely heavily on how storms behave earlier in the day.
Hodographs become quite favorable for tornadoes as we move
through the evening hours, but the main question will revolve
around the surface airmass thermal characteristics given the
passage of the MCS earlier in the day. Any areas that do manage
to recover may realize the over 500 m2/s2 of 0-1-km SRH and pose
a tornado threat. At this stage, given the trajectory of the
afternoon MCS, such a threat might be limited to south-central
Minnesota and north-central Iowa.
Thursday and Friday: Cooler and Drier
Northwesterly flow settles in for the latter part of the week
in the wake of our midweek storms and holds temperatures near
seasonal norms for this time of year. With low level moisture
slow to depart during the day on Thursday, steepening low-level
lapse rates may result in diurnal showers developing during the
day, with the showers sliding southeastward as drier air filters
south during the afternoon. Friday is shaping up to be the
coolest and driest day of the forecast period as a 1020-mb
surface high pressure slides through, but highs should still top
out near 80 degrees.
Saturday and Sunday: Next Round of Stronger Storms
Return flow builds in behind the departing ridge early Saturday,
with surface dewpoints rebounding into the 60s by Saturday
afternoon. The medium range solutions are in modest agreement
with a sharp shortwave impinging on the backside of the
synoptic ridge and thus we should see strong to severe storms
somewhere across the Upper Midwest, but enough differences exist
in the placement of the surface baroclinic zone make it
difficult to nail down any further specifics on threats and
locations. How convection unfolds on Saturday and the timing of
the shortwave passage will play a role in the threat area for
Sunday, though the southwesterly flow is strong enough that the
warm sector may have time to recover on Sunday and result in
repeated rounds of storms each day. Stay tuned for more details.
Next Week: Warming Up
Upper ridging amplifies over the central and eastern CONUS for
much of next week, resulting in southwesterly flow across the
region and with it the first real surge of summertime heat.
There exists some modest synoptic differences with the various
ensemble members with respect to the strength of the ridge,
with the more amplified solutions resulting in warmer and drier
conditions whereas the flatter solutions bring periodic bouts of
thunderstorms and cooler temperatures as shortwave
perturbations ripple northeastward over the Dakotas. The
resultant precipitation forecast contains a smattering of 20 to
40 percent probabilities for the end of the forecast period, but
these will be honed in over the coming days as the strength of
the ridge is better analyzed. What is more certain is that we
will see above average temperatures with over 70 percent of the
available guidance pushing the mid-80s for highs and 20 to 30
percent of the members exceeding 90 degrees.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 700 PM CDT Tue Jun 11 2024
VFR conditions will dominate the period but Wednesday is an
interesting forecast day. Vigorous moisture advection will
occur over western MN later tonight and into the morning hours
with TSRA development expected there. The trajectory brings
these storm chances southeast toward the area. At this time,
probabilities for storms increase both as the day wears on, but
also from east to west. Short term high res models converge on a
solution of increased storm coverage after about 3pm. Thus KRST
will have a better chance of being affected by storms Wednesday
later afternoon but KLSE still has chances as well (30 vs 60%
for KLSE and KRST, respectively).
Severe storm chances: airfields will want to be aware that there
is a chance for severe storms with damaging winds looking like
the main threat, but large hail is also possible. Again,
somewhat higher chances further west.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
UPDATE...Baumgardt
DISCUSSION...Skow
AVIATION...Baumgardt
Area Forecast Discussion
National Weather Service Boise ID
839 PM MDT Tue Jun 11 2024
.DISCUSSION...Satellite imagery has detected at least four
active wildfires in Southwest Idaho: two near Twin Falls, one in
south Ada County, and one south of Jordan Valley. As of 7:30 PM
MDT, all fires have been reported to be less than 10 acres.
Smoke is not expected to be an issue across southern Idaho at
this time due to an upper-level low moving across southern
Alberta, Canada, accompanied by a dry cold front that has
already reached parts of southeast Oregon. This front will
continue moving southeast, reaching Ontario around 10 PM MDT,
Boise around 11 PM MDT, Mountain Home around 1 AM MDT, and Twin
Falls/Jerome around 3 AM MDT.
The highest winds tonight will be between Baker Valley and the
Lower Treasure Valley. Baker City has already reported wind
gusts up to 37 MPH, and similar gusts are expected to reach
Ontario. Gusts will be slightly lower as the front moves up the
Upper Treasure Valley and Western Magic Valley, with gusts up to
20-25 MPH. The passage of the front overnight will result in
temperatures about 5 degrees cooler on Wednesday.
Winds have been updated to reflect current observations and the
latest high-resolution models for tonight into Wednesday
morning. The new data indicates slightly higher wind speeds than
previously forecasted. An updated forecast will be issued
shortly.
&&
.AVIATION...VFR and mostly clear. Surface winds: W-NW 5-15 kt.
Gusts 20-30 kt KBKE-KONO-KMUO late tonight/early Wednesday as a
dry cold front moves through. Winds aloft at 10kft MSL: W-SW
15-30 kt.
KBOI...VFR under clear skies. Surface winds: NW 7-13 kt. Gusts
up to 20 kts between 05Z and 08Z.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Thursday night...A weak north
Pacific upper trough will bring about 5 degrees cooling Wednesday
as it moves inland north of our CWA. Thursday looks as hot as
today as a short wave upper ridge comes inland ahead of a deep
upper trough from the Gulf of Alaska. Generally clear skies
until Thursday when clouds begin in southern zones. Models
develop enough instability near the ID/NV/UT tri-point for
a 10-20 percent chance of high-based thunderstorms Thursday
evening. Tonight and Wednesday night will be seasonably cool
with dry air and clear skies. No significant smoke indicated by
HRRR model. Thursday night looks several degrees warmer with
cloud cover and higher dew points. Winds will be light except in
southern Harney and Malheur Counties Thursday afternoon/night,
when west winds blow 15 to 25 mph with gusts to 30 mph.
LONG TERM...Friday through Tuesday...A deep upper trough from
the Gulf of Alaska will come inland and through our CWA Friday
through Tuesday with much cooler air. Initial surface cold front
will pass through Friday. Pre-frontal gusty southwest winds will
shift to west/northwest 10-20 mph. High temps Friday will be in
the upper 70s through 80s. A second cold front will increase
northwest winds to 15-25 mph with afternoon gusts 25 to 35 mph
Saturday in open terrain. Highs Saturday will lower to the mid
60s to mid 70s, then mainly 60s Sunday and Monday, with breezy
northwest winds continuing. Models keep pcpn generally north
of our CWA with the best chance (20-40 percent) Sunday night
in the central Idaho mountains. Model consistency breaks down
Monday with ECM bringing the main trough axis through our CWA
while GFS leaves it off the northwest coast. Consensus for now
is with the ECM for continued cool, breezy weather Tuesday.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
www.weather.gov/Boise
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DISCUSSION...JDS
AVIATION.....JDS
SHORT TERM...LC
LONG TERM....LC
Area Forecast Discussion
National Weather Service Burlington VT
1048 PM EDT Tue Jun 11 2024
.SYNOPSIS...
A partly cloudy sky will persist overnight with some patchy fog
possible in the deeper valleys as temperatures fall back into
the 50s. Wednesday will feature intervals of clouds and sun with
a few widely scattered showers across the higher terrain. Much
warmer and drier weather returns briefly for Thursday, before a
cold front produce another round of showers on Friday. A
beautiful weekend is on tap with plenty of sunshine and
comfortable temperatures.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 1046 PM EDT Tuesday...Main adjustment was to add a few
isolated showers for northeastern Vermont where some weak
showers are moving east to west. These should be dissipating,
but can`t rule out some sprinkles through the overnight hours.
Otherwise, clouds are increasing east to west as well limiting
the threat of fog. The forecast remains on track.
Previous Discussion...Mid/upper lvl closed cyclonic circulation
has redeveloped over eastern NY per latest GOES-16 water vapor
imagery and RAP upper air analysis, while dry air aloft prevails
acrs our cwa. However, shallow moisture and instability per
sounding data has resulted in plenty of strato cumulus clouds
acrs our cwa this aftn, with a few pockets of clearing acrs the
CPV and parts of central VT. Soundings show intervals of shallow
moisture btwn 975mb and 850mb acrs our cwa overnight, which wl
result in some partial clearing. Where areas of clearing
develop, patchy fog is possible, given light winds and temps
approaching cross over values. Lows similar to previous couple
of night with values in the mid 40s to mid 50s. On Weds, a weak
vort and slightly better moisture/instability, especially
northern VT and parts of the NEK wl help in the development of
widely scattered showers. Have continued with pops in the 15-25%
range for NEK VT and 15-20% probs for the dacks. Any showers wl
have limited vertical structure given sfc based CAPE values
<500 J/kg, but shower motions wl be <10 knots. So a few
localized heavy downpours are possible, but majority of the area
should remain dry. Highs on Weds should be warmer based on
progged 925mb temps btwn 14-15C, supporting values in the upper
60s to mid 70s. Weds night any showers quickly dissipate by
sunset with clearing skies and mostly light south/southwest
winds. Some patchy fog is possible eastern VT and parts of NEK
of VT, where better potential for rain showers occurs on Weds.
However, have noted increasing south/southwest flow by 06z,
especially western CWA, which may limit potential. Have not
included in fcst attm. Temps are similar to previous couple of
night with lows upper 40s to upper 50s.
&&
.SHORT TERM /THURSDAY NIGHT/...
As of 353 PM EDT Tuesday...Expect above normal highs on Thursday with
temperatures surging into the low to mid 80s, although warming could
be delayed slightly if there is any morning fog in eastern Vermont.
There will be a lot of dry air aloft through the day on Thursday
that will help keep instability low despite ample low level warm air
advection. A modest pressure gradient will result in breezy south to
southwesterly wind, with gusty conditions becoming increasingly
favorable in the afternoon hours as boundary layer deepens. Forecast
soundings show mixing above 700 millibars where wind speeds will be
in excess of 30 MPH, supporting peak gusts in the 20 to 25 MPH range
in many locations. The temperature difference between the air and
lake should minimize the mixing on Lake Champlain and other larger
lakes, generally keeping wind speeds lower than over land during the
afternoon/evening. Low level wind will be channeled in the St.
Lawrence Valley where gusts above 30 MPH are favored at times. A
shower with a slight chance of thunder remains possible towards
sunset in this region, but most model guidance at this time suggests
a pre-frontal trough will still be too far west to support
precipitation even in our western areas through the daytime hours.
After that time, a vigorous shortwave trough that is currently in
southern British Colombia is progged to approach our region with
relatively good agreement across deterministic model guidance. This
upper level forcing combined with a surface trough will trigger
showers overnight. Forecast soundings show elevated instability that
suggests some rumbles of thunder will be possible, with best chances
in the predawn hours moving from west to east. Greatest PoPs
continue to be over northern New York and far northwestern Vermont,
with generally lower chances of these showers heading south and east
as best upper level forcing tends to shift north of due east as the
trough crosses our region. While rain showers could produce heavy
rain, rainfall amounts will be be modest. Deep layer shear looks
more perpendicular than parallel to the trough axis, suggesting the
heavy rainfall threat is minimal as showers will move along steadily
without backbuilding or training. Temperatures will be rather warm
overnight with continued southerly flow and increasing cloud cover,
with rain-cooled air still supporting lows mainly in the 60s.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 353 PM EDT Tuesday...A cold front, following the pre-frontal
trough that moved through Thursday night, will quickly follow Friday
morning. Have kept a slight chance of thunder, although timing of
the front suggests relatively higher chances of a thunderstorm
exists in south central Vermont where temperatures have a better
chance to recover into the 80s before cooler and drier air advects
in behind the front. Overall, no significant weather is expected on
Friday, with a transition to a cool/dry pattern taking place in time
for Father`s Day weekend.
Temperatures will be chilly Friday and Saturday night, with the
latter night particularly cold for mid-June. Have bumped low
temperatures down a bit especially in the western Adirondacks where
patchy frost is not out of the question.
Dry and seasonable conditions will trend towards warm and muggy
early next week. While there is some model disagreement on the
extent of the heat for Tuesday, uncomfortably hot weather is likely
to develop midweek based on most model scenarios. The latest NBM
mean maximum temperatures are in the upper 80s to low 90s across
northern New York and Vermont; if dew points average in the mid 60s
as currently forecast, we could see heat indexes peak in the low to
mid 90s on Tuesday. Expect to see heat advisories concurrent with
major (3 out of 4) HeatRisk level if trends continue.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...Widespread cloud cover remains stretched
across our forecast area this evening, with a mix of VFR and
MVFR ceilings being reported. Those sites with clouds hovering
around 2200-3100 feet above ground level could continue to
experience bouncing between the two categories for the next few
hours as an inversion sets up again to keep moisture close to
the surface. The main challenge tonight will be potential for
IFR fog in some of the typical valley locations, including SLK,
MPV, and EFK. Best chance of this fog is between 06-12Z and is
still highly dependent on how much and where clouds clear out
overnight. Winds will generally be light and variable or terrain
based for the near future.
Outlook...
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. Chance SHRA, Slight chance TSRA.
Friday: VFR. Chance SHRA, Slight chance TSRA.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. NO SIG WX.
Sunday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Boyd/Taber
SHORT TERM...Kutikoff
LONG TERM...Kutikoff
AVIATION...Storm
Area Forecast Discussion
National Weather Service Cheyenne WY
459 PM MDT Tue Jun 11 2024
.KEY MESSAGES...
- Hot weather expected Wednesday as daytime highs climb into
the 85 to 95+ degree range across the entire area.
- Thunderstorm chances return to the region late this week,
along with the risk for severe weather Thursday and Friday.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 342 PM MDT Tue Jun 11 2024
Latest GOES WV imagery shows primarily zonal flow aloft with an
upper level closed low off the southern CA coast while the
polar jet sits near the Canadian border with an upper level
trough moving into BC. Zooming into southeast WY, latest visible
imagery shows cumulus development over east-central WY as well
as eastern Laramie Co with an enhanced convergence zone based on
surface observations. Precipitation chances are low, but
nonzero through early this evening as an isolated storm could
still develop. Will continue to monitor latest satellite trends,
but any storms that develop will likely be short-lived with
little to no precipitation.
Zonal flow aloft will continue Wednesday with 700mb temps climbing
near 15C as an upper level ridge builds just to the south over the
central Rockies. This will lead to a warm day across much of the CWA
with much of the NE panhandle reaching the mid-90s. With 700mb temps
will climb near the climatological 90th percentile value, we are not
looking to break record highs, but still could see temperatures just
a few degrees below for select locations. Latest NBM probability of
exceeding 100F degrees Wednesday afternoon is highest in the North
Platte River valley, up to 25%. Farther west of the Laramie Range,
scattered showers will develop in the afternoon with a weak
shortwave passing in the flow. Forecast soundings show inverted-V
profiles with dry low-levels and LCLs climbing above the freezing
level. While minimal precipitation is likely from these storms,
strong outflow winds will be possible in the vicinity. Hi-res
guidance does continue showers east along the I-80 corridor towards
Kimball before dissipating early in the evening.
Better chances for showers and thunderstorms arrive later this week,
starting on Thursday. SPC Day 3 Outlook currently has a Marginal
Risk reaching up into Laramie Co. Post-frontal upslope flow with an
upper level system passing over the central CONUS will increase
moisture convergence across southeast WY and northeast CO. Despite
southeasterly low-level flow, wind profiles are fairly
unidirectional aloft supporting of straight hodographs and splitting
storms. MLCAPE climb near 1000 J/kg with 40+ kt shear that will
support strong to severe thunderstorms Thursday afternoon along the
South Laramie Range and adjacent plains to the east and south of the
North Platte River valley.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 342 PM MDT Tue Jun 11 2024
An active start to the long term forecast is expected across
southeast Wyoming and western Nebraska. On Friday, a potent,
upper- level shortwave trough is progged to dig northeasterly
from southern Nevada to western Colorado throughout the day. As
this upper-level shortwave pushes towards the region, ample
synoptic lift is expected to develop from a combination of jet
dynamics and cyclonic vorticity advection at 500mb. A subtle,
700mb jet maximum is progged to be just southeast of the CWA,
broadly placing western Nebraska within the left exit region of
this low-level jet and further favoring lift across the region.
Strong southeasterly flow at the surface will advect in
significant moisture with dewpoints increasing into potentially
into the 60s for portions of western Nebraska, with 50F dewpoint
expected across far southeast Wyoming. NAEFS mean precipitable
water for 00Z Saturday is currently progged to near the 99th-
percentile for this area at this time of year. Looking more in-
depth into some of the convective parameters, MUCAPE values are
progged to well over 2000 J/kg with MLCAPE values approaching
2000 J/kg as well. Forecast soundings from the GFS suggest good
directional shear in the lowest levels of the atmosphere, steep
low- level lapse rates, and DCAPE values near 1000 J/kg.
Forecast soundings across western Nebraska suggest bulk shear
values approaching 50kts, with precipitable water values
approaching 1.5 inches. These indicate a potentially significant
hail threat across far southeast Wyoming and western Nebraska.
However, hodographs are progged to be straight across this
region, leading to an additional concern of slow-moving storms.
Slow-moving storms accompanied by 95th-99th percentile
precipitable water leads to and increase concern of torrential
downpours with any storms that develop and the slow moving
nature could lead to a significant flooding threat. The Weather
Prediction Center has a small portion of the CWA under a
Marginal risk for excessive rainfall on Friday, but this could
move further west over the next few days. Overall, Friday looks
to be a favored day for severe weather across western Nebraska
and far southeast Wyoming. This setup will continue to be
monitored as it approaches and more consistency develops within
the models and hires models.
The remaining long term forecast will feature quasi-zonal flow aloft
across the region with 700mb temperatures increasing into the 10 to
20C range throughout the long term. Warm temperatures are expected
with highs in the 70s to near 90s across western Nebraska. Could see
some daily chances for isolated showers and maybe a thunderstorm or
two, but coverage will be very low. Additionally, zonal flow aloft
will lead to breezier conditions across the region, though winds
should remain well below high wind criteria.
&&
.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 456 PM MDT Tue Jun 11 2024
High pressure over southeast Wyoming and Nebraska Panhandle
will keep skies clear through the next 24 hours and beyond.
Latest HRRR and HREF guidance showing no chances for lower
flight conditions during this time. Westerly downslope winds
backs up that thought. No weather impacts to aviation interests
expected.
&&
.HYDROLOGY...
Issued at 342 PM MDT Tue Jun 11 2024
Flows remain just below flood stage on the Medicine Bow River
near Elk Mountain with a slight trend downward the past few days
with early morning crests. However, with the warm weather
expected the next few days including overnight lows in the
mid-40s at higher elevations, decided to extend the Flood Watch
for snowmelt through Thursday morning.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MB
LONG TERM...AM
AVIATION...GCC
HYDROLOGY...MB
Area Forecast Discussion
National Weather Service Des Moines IA
1034 PM CDT Tue Jun 11 2024
...Updated for the 06z Aviation Discussion...
.KEY MESSAGES...
- Few isolated storms possible before sunset northeast, but
severe threat remains low this afternoon/early evening.
- Strong to severe storms possible Wednesday afternoon and
evening especially north and east.
- Additional storms, possibly severe, expected south Thursday
as well.
- Continued warming into midweek as highs reach into the 90s.
- Slightly cooler/drier Friday but heat and storm chances return
for the weekend.
&&
.DISCUSSION...
Issued at 354 PM CDT Tue Jun 11 2024
Rest of Today:
Scattered showers this morning fizzled out by about midday leaving
mostly clear skies through much of central Iowa except for some
budding cu this afternoon. Surface boundary connected to the main
trough over southern Canada continues to move through the area this
afternoon into evening but overall chances for any isolated storm
development remain fairly low, around 20% or less with dew points
well into the 60sF as many models suggested not being realized. As
of 3 PM, dew points were in the 50s to low 60sF at a few sites with
temperatures in the 80s. These overall lower levels of moisture
should continue to help limit any storm development, though won`t
completely rule out an isolated storm with gusty winds or small hail
mainly in the far northeast, but overall chances for any severe
weather remain low this afternoon into early evening with any storm
development chances waning completely by around sunset. Temperatures
tonight will be warmer than this morning and generally in the upper
50s to 60s.
Wednesday/Thursday:
Wednesday will be noticeably warm and humid as warm air advection
amplifies with the thermal ridge moving through the region and H850
temperatures nearing +20C or more by Wednesday afternoon. This heat
will be paired with surging moisture as dew points reach towards or
well into the 60sF which translates to high temperatures in the
upper 80s to 90s and heat indices in the low to mid 90s for many. A
few theta-e advection induced showers or storms are possible in the
morning to early afternoon mainly north but moisture may once again
be an issue with this early day activity with forecast soundings
looking fairly dry. Attention then turns to the the main shortwave
and associated frontal boundary that will be dropping south through
MN through the day with storms, some severe, possible in two rounds
Wednesday, the first in the later afternoon to evening, and the
second close on the heels of the first, but in the later evening to
early overnight. Some questions remain on the placement of the
storms, especially in the coverage of storms to the south and west,
but storm chances are highest, >60% chance, over northeast areas, as
this is the most likely area to see storms given current CAM trends
and overall parameter space. The extent of capping could be the
limiting factor in portions of central and western Iowa where
afternoon H700 temperatures look to be near +10 to +12C which can be
tough to overcome. As noted in the previous discussion, the overall
parameter space is pretty good with the warm, humid environment
surging MLCAPE values into the 1000-2000+ J/kg range per NAM
and RAP soundings in portions of northern Iowa with storm
relative inflow around 25-35 knots and overall bulk shear of
30-40+ knots. Strong to severe storms are possible with damaging
wind gusts (DCAPEs over 1000 J/kg with lower level dry air in
soundings) and large hail (elongated hodographs) the primary
threats. Won`t completely rule out the possibility of a tornado
if everything can come together with boundary interactions given
increasing helicity values into the early evening, but overall
LCLs are high which would be a limiting factor. Heavy rain may
also occur, especially in areas that see multiple rounds of
storms like the northeast, where rain amounts may near 2-3+
inches, as noted in the 24 hour QPF HREF localized probability
matched mean. Progressive nature of storms should overall limit
hydro issues, but will certainly keep an eye on this with
potential for higher rainfall rates.
Although storms wane by the early overnight, additional showers are
possible Thursday morning with the location of the front towards
southern Iowa the location for new storm development on Thursday
afternoon to evening in another warm, humid, and unstable
environment as highs climb into the 80s to 90s with heat indices in
the upper 90s over far southern Iowa. Storm threats will better be
determined based on location of the front and timing, but severe
storms may again be possible with wind hail, and will even need to
watch the tornado potential depending on how the mesoscale
details evolve.
The overall take away for Wednesday and Thursday is to monitor the
forecast for updates with a SPC Day 2 Slight Risk (Level 2 of 5)
Wednesday north, with a Day 2 Marginal Risk (Level 1 of 5) extending
through much of the rest of the area, and a Day 3 Marginal Risk
(Level 1 of 5) over far southern Iowa on Thursday.
Friday and Beyond:
A small reprieve is expected on Friday with slightly cooler
temperatures, though still in the 80s, and lower dew points.
Additional storm chances return for the weekend with more building
heat as temperatures climb into the upper 80s to 90s again on Sunday
and Monday with upper 90s heat indices south.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1031 PM CDT Tue Jun 11 2024
VFR conditions prevail over the area. Chances for shra/tsra
increase by mid to late afternoon over portions of northern Iowa
as activity dives south and east out of MN. Considerable
uncertainty remains with the south/west extent and timing of
this activity, but did include a mention at KMCW and KALO to
highlight the most probable window based on the latest model
guidance.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...KCM
AVIATION...Martin
Area Forecast Discussion
National Weather Service Green Bay WI
1051 PM CDT Tue Jun 11 2024
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- Periods of light rain are expected through this evening. A
thunderstorm is possible, but no severe weather is anticipated.
- There is a Marginal Risk of severe thunderstorms late Wednesday
afternoon and Wednesday evening when one or more complexes of
storms could impact the region. The latest indications suggest
locations over central Wisconsin have the highest chance of
seeing strong storms, which may contain gusty winds and hail.
Confidence is low where these thunderstorms will track.
- Well above normal temperatures are forecast from Sunday into the
middle of next week. Heat indices may surpass 90 degrees at
times.
&&
.DISCUSSION...
Issued at 232 PM CDT Tue Jun 11 2024
Short Term...Tonight and Wednesday
The latest RAP analysis and satellite/radar imagery show a cold
front moving across the northern Mississippi Valley with help from
a modestly potent shortwave trough. A broken band of rain along
the leading edge of a warm advection zone is proceeding east at
about 30 kts across central Wisconsin. This band of showers will
likely weaken somewhat, but not enough to dissipate before
reaching eastern WI. The trailing cold front has been inactive
so far today, but convective clouds are building along the
boundary. Between this system and the next system arriving on
Wednesday, precip and severe weather chances are the focus of this
forecast.
Precip Trends: Behind the light band of rain showers, the
convective allowing models indicate that additional showers may
redevelop later this afternoon. No thunderstorms are expected.
Right along the front, a few thunderstorms could develop early
this evening along a narrow ribbon of 600-800 j/kg cape. If
thunderstorms develop, central WI will have the greatest chance.
Brief gusty winds will be possible through the evening if storms
develop. Then quiet conditions return overnight.
Then within fast, zonal flow aloft, light showers could develop
over north-central and far northeast WI in the afternoon. But all
eyes will be on southeast Minnesota and northern Iowa for strong
thunderstorm development along the instability gradient in the
afternoon. Some storms could make a run at central Wisconsin after
5 pm.
Severe weather chances: Within a region of strong instability
(2000-3000 j/kg mixed layer cape), strong to severe thunderstorms
are forecast to develop over central Minnesota around 1-2 pm.
These thunderstorms are forecast to grow upscale into a complex
and track along the cape gradient on the nose of the 35-45 kt low
level jet to the southeast and into southwest Wisconsin by late
in the afternoon. While tracks and timings may still change, the
latest guidance suggest central WI will be on the northern edge of
any convective complex. Some guidance shows instability upwards of
1500 j/kg sneaking into Wood, Portage, and Waushara counties where
a severe wind/hail threat may develop by 22-23z. If it comes to
fruition, the strong to severe thunderstorm threat should end
relatively early on Wednesday night due to fast forward motion of
the complex, perhaps around the 10 to 11 pm time frame.
Chances appear lower than previous forecasts over north-central WI
where another complex could develop over the Arrowhead of
Minnesota before tracking east into Lake Superior.
Long Term...Wednesday Night Through Tuesday
The main focus of the extended forecast will be on the evolution
of the 500mb pattern through the end of the week, which may bring
both our next round of strong active weather and well above normal
high temperatures.
Active weather underway from late Wednesday afternoon will
rapidly push through the region during the evening hours,
departing by the early overnight hours. The strongest storms may
yet move through portions of central Wisconsin, but general
consensus still brings the strongest storms south of the area. See
the short term discussion for additional information.
The cold front that brought the active weather through on
Wednesday is expected to drop well south of the area Thursday,
bringing back quiet conditions for our area. Any redevelopment
along the cold front will stay south, impacting primarily
northern Illinois and southern Wisconsin.
As high pressure begins to depart Saturday, southerly return flow
will begin to ramp up. A strong push of warm moist air will cross
the region by late Saturday, bringing with it another chance for
some active weather. Instability parameters due suggest some
potential for stronger storms, so Saturday afternoon through
Sunday will be a time period to watch for severe potential.
Behind this, the area is expected to be well in to the warm
sector. Long range guidance still brings high temperatures well
into the 80s both Sunday and Monday, with a chance for low 90s.
These temperatures may still come down on Sunday depending on how
quickly any precipitation and cloud cover pushes through from
Saturday, but the warmup remains in the forecast.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1051 PM CDT Tue Jun 11 2024
Some isolated showers are possible across eastern Wisconsin around
midnight as a cold front tracks through the rest of the region.
Given the isolated nature of the activity, will only include a
VCSH in the eastern TAF sites for the first few hour or two to
account for these showers.
Generally good flying weather is expected through Wednesday
afternoon. By late in the afternoon or early evening, shower and
thunderstorm chances will increase as a warm front lifts north
across the western Great Lakes with attendant cold front pushing
in Wednesday night. Current CAMs models are not clear on how
widespread the activity will be across the area with some
solutions splitting the storms to the north and south with our
area not getting much in the way of showers or thunderstorms.
Therefore, will only include a VCSH Wednesday night as there is a
chance the area does not get much in the way of rainfall with this
system.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....MPC/Uhlmann
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Pendleton OR
821 PM PDT Tue Jun 11 2024
.UPDATE...
Winds have begun to decrease across the region and have lowered
enough that the wind advisory has been cancelled. Winds will be
breezy for several more hours before finally dropping during the
overnight hours. Otherwise, just made some minor tweaks to
overnight lows.
.AVIATION...
06Z TAFS...VFR conditions expected for the next few days. DLS will
keep 20 to 25 kt gusts for a few hours before winds decrease to
around 10 kts. Winds will increase and become gusty again with 20
to 25 kts in the afternoon before decreasing in the evening.
Similarly PDT will keep gusts for a few hours but will have winds
10 kts or less on Wednesday. All other locations should have 10
kts or less through the period.
&&
.PREV DISCUSSION... /issued 424 PM PDT Tue Jun 11 2024/
Updated for Aviation...
AVIATION...
00Z TAFS...High Confidence (95-100%) in VFR conditions through the
period. Gusty winds this evening will subside in most locations
this evening and everywhere overnight, with winds becoming 10 kts
or less and remaining there. The only exception is DLS which will
have gusty winds 20 to 25 kts again Wednesday afternoon.
PREV DISCUSSION... /issued 258 PM PDT Tue Jun 11 2024/
SHORT TERM...Tonight through Thursday Night...
Key Messages:
1. Breezy to windy conditions through this evening with wind
advisories issued for the Kittitas Valley, Eastern Columbia Gorge
and Simcoe Highlands.
2. Cooler Wednesday but warming back up Thursday.
A weak shortwave is passing to our north through central British
Columbia this afternoon and it has a cold front that will cross our
area a few hours from now. Radar is not showing any shower activity
and satellite shows clouds mainly west of the Cascades with mostly
clear skies over our area. The main concern today is the winds,
which will be peaking later this afternoon and then decreasing this
evening after sundown. The GFS, NAM, SREF and GEFS all have pressure
differences between Portland and Spokane in excess of 10 MB with the
RAP is between 9-10 MB. These values point to windy conditions in
the Columbia Basin and adjacent valleys. Observations have been
mainly in the 20 to 30 mph with gusts to 35-40 mph so far but winds
are increasing. Ellensburg had northwest winds of 31 mph gusting to
46 mph in the latest observations. NBM probabilities show a greater
than 90 percent chance of wind gusts of 40 mph in Kittitas Valley.
Simcoe Highlands, Columbia Gorge and and a 50-90 percent chance in
the Blue Mountain Foothills later this afternoon. Chances for a wind
gust of 49 mph are 70 percent chance in the Kittitas Valley and 50-
60 percent in the Simcoe Highlands and Columbia Gorge but drop off
to less than 15-30 percent elsewhere. Current wind advisories for
the Kittitas Valley, Simcoe Highlands and the Eastern Columbia River
Gorge look good and will remain in effect through 11 PM this
evening. Winds look to remain just below wind advisory levels in the
Columbia Basin, Blue Mountain Foothills and Yakima Valley. Relative
humidities are as low as 20-25 percent as well and a few weeks from
now, would probably need to consider a Red Flag Warning for fire
danger but believe the vegetation is still a bit too green for large
fires.
As winds die down this evening after the cold front passage, colder
air will move over the area and along with clear skies, temperatures
will drop off as much as 8 to 12 degrees from last night with lows
in the 40s in the lower elevations and in the mid 30s to lower 40s
in the mountains. Tomorrow, with the shortwave moving into the
Rockies and the next trough still up in the Gulf of Alaska, a zonal
westerly flow will be over the area and sunny and dry weather is
expected. Winds will be fairly light with only the Kittitas valley
and Columbia River Gorge reaching 10 to 15 mph in the afternoon.
Lingering cooler air will drop temperatures 5 to 8 degrees from
today and highs will be in the mid 70s to lower 80s in the lower
elevations and in the mid 60s to mid 70s in the mountains. Lows
Wednesday night will be a few degrees warmer than tonight but still
a few degrees below normal in most locations.
On Thursday, a strong upper low and trough will begin moving south
out of the Gulf of Alaska to the central british Columbia coast.
This will send a warmer southerly flow over our area. There will
continue to be no chance of precipitation through Thursday night but
there will be increasing cloudiness along the Cascades and in the
northern portion of the area in the afternoon and Thursday night.
Winds will continue to be light through Thursday evening but will
become breezy overnight in the Columbia Basin and adjacent wind
prone valleys. Highs Thursday will rebound back to the lower to mid
80s with 70s and lower 80s in the mountains. Lows Thursday night
will warm to the mid 40s to mid 50s. Perry/83
LONG TERM...Friday to Tuesday...The main sensible weather
highlights include:
- Breezy to locally windy conditions across our windy/climo-prone
areas Friday and Saturday,
- Cooler, below normal temperatures with the coldest conditions this
weekend, particularly Sunday, and
- Unsettled weather this weekend onward with generally periodic
chances, highest along the crest of the Cascades and eastern
mountains.
The long term initially will be characterized by a deep, anomalous
upper-level closed low offshore British Columbia with southwest flow
aloft with the expectation of a weak front moving across Thursday
night. Ensemble guidance is in very good agreement with the synoptic
pattern as cyclonic flow dominates through Saturday with the upper
trough forecast to evolve to the WA/BC region. A modest synoptically
imposed surface pressure gradient will develop late Friday and
persist Saturday with the stronger winds prevailing Saturday.
Limited support aloft in the lower troposphere until more so
Saturday. 24-hr peak daily gusts chances for exceeding 40 kts around
60-95% over the eastern Columbia Gorge into the Lower OR Basin,
Simcoe Highlands, and the Kittitas Breezeway, highest across the
later area. Slightly higher probs, by 10-15%, on Saturday across the
same locations. That said, chances for exceeding 45 mph are around
25-50%, except for 60-90% across the Kittitas Valley. Meantime, the
best chances (50-80%) for precip in the long term will arrive
Saturday across the WA Cascades near the crest.
As the upper trough evolves, an cooler air mass is anticipated to
take hold this weekend. This in tandem with limited sky cover across
some areas will favor radiational cooling when/if combined with
light winds as well. Of which, lows will be around 3 to 10 degrees
below normal area-wide Sunday morning across the lower elevations;
lows will be into the 30s across parts of central OR. Confidence is
low right now in central OR seeing lows below 32 with chances
peaking around 25% across Redmond.
Thereafter there are modest differences in the 500 mb pattern
beginning Sunday that grow more by Monday/Tuesday next week with the
latest guidance in fairer agreement compared to overnight.
Specifically, the amplitude and character of the upper trough early
next week. There is potential for embedded wave(s) to deepen this
upper trough Monday over the Northern Intermountain West, or the
other possible outcome is a pattern that becomes more progressive,
less amplified with open waves/shortwave troughs passing across the
PacNW. Confidence in more persistent upper-level troughing affecting
the region around ~80% and 90% Monday and Tuesday, respectively.
Currently there are low to moderate chances (15-50%) across the
upper slopes of the eastern Cascades and the eastern mountains
Sunday, highest odds in the former. Lower confidence on Monday and
Tuesday with chances more broad and lower overall (15-40%).
Lastly, there are concerns (~15-20%) for isolated thunderstorms
Monday, however, confidence is low giving the spread in guidance
and uncertainty this far out in time.
AVIATION...Previous discussion...18Z TAFS...VFR conditions prevail
during this TAF period. Most sites currently have FEW-SCT clouds
except KRDM with clear skies. Cloud coverage will decrease
throughout the day for KDLS/KPDT/KALW/KPSC. All sites will
experience gusty westerly winds at 20-30kts with sustained winds
at 15-25kts this late morning. These wind conditions should
decrease overnight but afternoon for KDLS (>50% confidence).
Feaster/97
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 47 76 46 83 / 0 0 0 0
ALW 48 79 49 86 / 0 0 0 0
PSC 50 81 50 87 / 0 0 0 0
YKM 44 79 46 84 / 0 0 0 0
HRI 47 81 48 87 / 0 0 0 0
ELN 45 76 46 82 / 0 0 0 0
RDM 40 77 43 83 / 0 0 0 0
LGD 43 74 45 84 / 0 0 0 0
GCD 44 79 46 89 / 0 0 0 0
DLS 50 80 50 85 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
SHORT TERM...77
LONG TERM....80
AVIATION...77