Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/10/23
Area Forecast Discussion
National Weather Service La Crosse WI
1042 PM CDT Tue May 9 2023
.DISCUSSION...(This evening through Tuesday)
Issued at 213 PM CDT Tue May 9 2023
Key Messages:
- Scattered Storm Chances Primarily Along Our Western Counties In
Southeast Minnesota and Northeast Iowa Through Much of The
Latter Half of The Week, Increasing Into/Through The Weekend
- Maximum Daytime Temperatures Into The 70s and 80s For Much Of
The Area For The Rest Of The Work Week
- Possible Return Of Omega Block Centered Over The Pacific
Northwest Into The New Work Week
Ongoing Convection This Afternoon:
Monitoring thunderstorms advecting north-northeast from north-
central Iowa into southern Minnesota early this afternoon,
slightly upstream of a surface low. This low appears to be tied
to an occluded boundary which leads to another stronger surface
low farther south in Kansas, according to surface observations.
Synoptic flow evident in water vapor satellite imagery loops
depict an northeast propagation of upper level flow. RAP SPC
mesoanalysis has backed storm relative winds in lower levels over
the last three hours, resulting in thunderstorm impacts grazing
our west-northwest periphery in the near term. Later in the
afternoon-evening, SBCAPE expected to build near 1500 J/kg in
west-central Iowa, with surface winds backing over the last couple
of hours hinting at subsequent initialization of storms. Given
the more southerly initialization location of these storms and the
similar northeast trajectory, these storms have increased
likelihood to reach the local forecast area this evening. However,
timing of these storms locally will be post-peak heating and
therefore expected to be on the decline. Best shear, instability,
and lapse rates abstain from the local forecast area this
afternoon and evening. Have trimmed but continued precipitation
potential along our northwestern periphery. However, will be
monitored this afternoon for further development.
Midweek Maximum Daytime Temperatures:
Mid level heights continue to build through Wednesday, with low
level anticyclonic flow passing through Wisconsin during the day.
Timing of passing high pressure abates strongest southeast
moisture advection off to our west. Result is highest (70-100%)
confidence (HREF, EPS, GEFS) for maximum daytime temperatures in
the 70s for much of the area. Model certainty shows raw models
supporting maximum daytime temperatures in the low 70s with bias
corrected models in the high 70s to low 80s. With NBM being below
50th percentile of guidance, have bumped up maximum daytime
temperatures a couple of degrees with short term higher
resolution guidance. Confidence decreases (GEFS:40- 100%;
EPS:80-100%) for the location of the synoptic ridge into Thursday
as a (currently evident in WV imagery) West Coast trough phases
and lifts through the Central Plains. Cluster analysis (09.00Z)
agreement and SREF (09.09Z) confidence suggest this Central
Plains closed mid level cyclone losing all upper level forcing
Thursday night, and rejoining the parent flow through Friday.
Therefore, the more anomalous increased low level theta e
expected to remain west of the forecast area during this time.
Nevertheless, NBM confidence for greater than 80 degree maximum
daytime temperatures increase from 50% Wednesday afternoon in the
Mississippi River Valley to 70-90% for much of the area (outside
of central Wisconsin) on Thursday, into 60-80% for Friday.
Sporadic Storm and Precipitation Chances:
Associated precipitation chances primarily impact farther west
from the Central to Northern Plains with smaller chances
impacting our western/southwestern counties from Wednesday night
into Friday. Again, dependent on location of the closed,
weakening upper level low flinging lobes of positive vorticity
advection towards the local forecast area. Deterministic
(NAM/NAM12/GFS) soundings struggle to saturate with minute,
skinny, temporary CAPE profiles Wednesday night. As previously
mentioned, the increased low level theta e warm sector remains off
to our west while the potentially vertically stacked surface low
wraps up into the latter half of the week. Therefore, best storm
chances abut our southwestern counties in northeast Iowa through
Friday with higher confidence (70-100%: GEFS/EPS;09.09Z) for >500
J/kg of CAPE just off to the southwest. Have decreased
precipitation chances from the National Blend Wednesday night,
collaborating with western neighbors based on higher resolution,
slower, and drier guidance building increased heights locally.
These longer range ensembles exhibit low (EPS; 10-50%) to medium
confidence (GEFS;40-80%) for >500 J/kg grazing northeast Iowa
through Friday night. The morning SREF (09.09Z) is slightly more
rambunctious through Friday, bifurcating 70% confidence for >500
J/kg from northwest to southeast across the forecast area. Machine
learning guidance reflects this better instability shunting off
to our southwest with higher probabilities for severe hail in
central Iowa. All in all, while higher confidence for severe storm
chances abate from the local forecast area, have continued with
NBM Probability of Thunder given the longer forecast hour, which
increases PoT Thunder chances to 30% Thursday afternoon/evening in
our extreme west becoming area wide Friday afternoon/evening.
Weekend Weather & Overall Rainfall Impacts:
Impacts through the weekend will be tied to an anomalously (90th
percentile according to SPC sounding climatology & NAEFS/ENS;
09.00Z 2-3 standardized anomalies) moist air
mass of 1.0" and greater precipitable water values enveloping
nearly all of Wisconsin. Regarding overall amounts, highest ensemble
confidence (70-100%) suggests around 0.1" of precipitation
through Friday, increasing from 0.25-0.5" from Friday night
through the weekend.
Disagreement in the synoptic pattern increases through the weekend
with the long range ensembles (GEFS/EPS;09.09Z) showing moderate
confidence 30-80% for a quasi omega block. Cluster analyses (09.00Z)
agree on an anomalous (3-4 standardized anomalies NAEFS/ENS;09.00Z)
ridge and high pressure over the Pacific Northwest. Locally,
cluster differences surrounding potential troughing along the
northwest flow into the start of the new work week. NAEFS/ENS
suggest a maximum percentile upstream anticyclone over the
Northern Plains as well.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1041 PM CDT Tue May 9 2023
VFR conditions expected.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...JAR
AVIATION...Baumgardt
Area Forecast Discussion
National Weather Service Denver/Boulder CO
930 PM MDT Tue May 9 2023
.UPDATE...
Issued at 930 PM MDT Tue May 9 2023
Atmosphere certainly made due with the environment it was given
this evening. Most of the thunderstorms have weakened and exited
to the north and east with the exception of one severe
thunderstorm moving northeast into SW Morgan County. Made some
minor adjustments to the PoPs. Some CAMs are still holding onto
the idea for a later round of elevated convection later
tonight. Original forecast is on track for tomorrow with the
threat of thunderstorms and some strong to severe ones. Hi-res
guidance is again still changing by the run displying uncertainty
in the evolution of the convection, but is overall still
displaying the big picture of numerous storms across the region
tomorrow afternoon. There is still that limiter of how the morning
stratus will inhibit the instability for the day with model
soundings exhibiting a strongly capped atmosphere into the
afternoon. Better forcing with the approaching trough should
counteract this later that afternoon.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 313 PM MDT Tue May 9 2023
...SEVERE THUNDERSTORM POTENTIAL INCREASING WEDNESDAY...
Key Messages...
1. A conditional threat of severe weather still
exists this evening through most of the overnight hours across the
I-25 corridor and eastern plains
2. A more organized round of severe storms appears likely
Wednesday afternoon into Wednesday evening... with all severe
hazards possible...
An approaching trough axis will bring a variety of weather
hazards to Colorado over the next few days... with severe weather,
heavy rain, and mountain snow possible through the end of the
week. RAP Mesoanalysis and water vapor satellite show the center
of this upper trough just off central California coast this
afternoon. Broad southwesterly flow aloft is present ahead of this
trough axis, and the flow should strengthen and slowly back to
the south-southwest through tomorrow afternoon. This trough should
continue to progress eastward, eventually transitioning to a more
negatively tilted trough axis by Wednesday evening.
Before getting into Wednesday`s details... we can`t forget about
tonight`s more conditional severe threat. ML/MUCAPE is expected to
increase this evening and into the early overnight hours as
better low-level moisture streams back into the region, with an
EML/steep lapse rates aloft. Recent CAMs have gradually come on
board with isolated to scattered storms developing near the best
moisture convergence (I-25 corridor) this evening, shifting this
activity into the northeastern plains overnight. With MLCAPE
values increasing to 1000-1500 J/kg with deep layer shear near
40-50kt... large hail would certainly be a threat tonight, along
with a marginal severe wind threat. However, guidance has
struggled handling sfc moisture throughout the day, and has
largely been inconsistent with convective initiation/evolution
overnight. We may be stuck in "wait and see mode" for quite some
time, but the SPC`s marginal risk appears well-justified.
Any elevated convection overnight tonight should be out of the
area by Wednesday morning. Moisture advection should still be
ongoing with at least some low stratus across the plains, with dew
points sitting near 50F... setting the stage for a potentially
widespread severe weather event across the Colorado plains. From a
ingredients-based perspective, this does check most (if not all)
of the boxes for Colorado severe weather: (1) A strong, negatively
tilted trough axis approaching from the southwest, (2) ample
boundary layer moisture, (3) synoptic scale ascent from upper
level height falls/PVA, (4) moderate instability and shear.
Largely straight line hodographs would support both hail and
damaging wind threats from both left/right split supercells, with
a tornado risk also accompanying the latter of these two splits.
However... there is still quite a bit of uncertainty, and several
things that could deviate from our current forecast. The ongoing
struggles with the handling of tonight`s convection leaves a lot
of questions regarding the evolution of the low-level moisture
across the area overnight. There`s also the possibility that low
cloud cover remains too thick Wednesday morning, leading to poor
surface heating (and thus, stronger capping/weaker instability) in
the afternoon. And, like in almost any severe weather event here,
there is still questions about the overall convective evolution
through the afternoon hours. Still, the general thought remains
unchanged from last night... with scattered supercells developing
near noon, with gradual upscale growth through the evening hours.
A lot can change in 12-24 hours... so users are encouraged to
check back for frequent updates.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 223 PM MDT Tue May 9 2023
An upper level storm system will move from nwrn New Mexico into sern
CO by Thu morning and then track slowly northeast into far ern
CO/wrn KS by Thu night. Cross-sections show favorable QG ascent and
lapse rates will affect the area Wed night thru Thu night with
abundant moisture.
Showers and tstms will become numerous Wed night with some potential
for svr storms Wed evening across the plains. On Thu, rain and
tstms will continue with areas of heavy rain possible thru Thu
night.
By Fri morning, the storm system will be located over far nern
CO/swrn NE. Current data shows precip continuing on the back side
of the upper level low mainly along the I-25 Corridor into the
higher terrain. There certainly is potential for heavy snow, in the
mtns above 10000 ft, Thu aftn thru Fri morning north of I-70.
Total rainfall amounts from both the ECMWF and GFS show 1 to 3
inches possible across portions of the plains, I-25 Corridor and
foothills thru Fri morning.
For Fri aftn thru Fri night the upper level low weaken and will move
away from the area. As a result, precip chances should gradually
decrease by Fri aftn over the region.
On Sat, a secondary piece of energy will move into WY. There are
significant differences on how this feature is handled this weekend.
The ECMWF moves it westward into Idaho by Sun while the GFS has it
moving into Utah. Both models show lingering moisture affecting the
area as a surge of cooler air moves in behind a cold front. Overall
it looks cool and somewhat unsettled with a chc of showers and a few
storms. It appears most of this activity would occur over the
higher terrain.
By early next week, an upper level ridge will develop over the area.
This should lead to a drier pattern with temperatures near seasonal
levels.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 610 PM MDT Tue May 9 2023
A few storms are starting to pop in the vicinity of the terminals.
A few may be capable of gusty outflow winds. As higher moisture
moves in from the east tonight, there will be a threat for lower
clouds and perhaps another shot at convection late tonight. Timing
of the lower stratus remains uncertain and will depend on if
convection does develop in this late evening timeframe, but will
stick with 06-09z period for this to develop. Stratus continues
through the morning hours, eroding mid to late morning.
Main concern for Wednesday will be the thunderstorm potential in
the afternoon. Some uncertainty in the timing of first initiation
of storms. There should be storms initiating after 20z. There is a
threat for strong to sever storms as well which may entail gusty
winds and hail.
&&
.FIRE WEATHER...
Issued at 223 PM MDT Tue May 9 2023
Near critical to critical fire weather conditions have been
observed across the Red Flag Warning area. This will remain in
effect until 7PM when moisture begins to increase. Fire danger
will decrease Wednesday through the rest of next week.
&&
.HYDROLOGY...
Issued at 223 PM MDT Tue May 9 2023
Increasing coverage of showers and thunderstorms on Wednesday will
lead to at least a minor risk of flash flooding across the burn
areas Wednesday.
There will be some risk of flash flooding in the burn scars
Wednesday night into Thursday due to the potential for heavier
rainfall. At this time it appears Cameron Peak would be the most
favored.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Mensch
SHORT TERM...Hiris
LONG TERM...RPK
AVIATION...Mensch
FIRE WEATHER...Hiris
HYDROLOGY...Hiris/RPK
Area Forecast Discussion
National Weather Service Buffalo NY
1011 PM EDT Tue May 9 2023
.SYNOPSIS...
High pressure will promote mostly dry weather through much of the
week. A plume of smoke in the upper levels of the atmosphere from
wildfires in western Canada will continue to give the sky a hazy
look through at least Wednesday. Temperatures will be seasonably
cool through tonight, then a warming trend takes hold through the
end of the week.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
Dry weather prevails through Wednesday as high pressure builds from
northern Ontario province and Hudson Bay across the Great Lakes.
Center of the high eventually makes its way to Appalachians to
Carolinas late Wednesday night. This high and the flow off the lakes
has led to locally breezy northeast winds since late morning over
western NY. These winds will diminish into early this evening while
turning to the northwest, then eventually southwest.
Tonight, high pressure overhead results in light winds, clear skies
and great radiational cooling. Continue to ride with min temps below
even the lowest model guidance. Lows inland from the lakes will be
in the mid to upper 30s, with a few lower 30s in the coldest
Southern Tier Valleys and Lewis County. There will be frost, but
greatest coverage of it will be where frost-freeze headlines have
not started yet (Cattaraugus, Allegany, Lewis and Jefferson
counties). Frost coverage does not appear great enough to warrant a
Frost Advisory for zones that are eligible for a headline, but have
put a mention in HWO for a heads-up to protect any sensitive plants,
vegetation.
On Wednesday, temps aloft increase and all things created equal,
highs on Wednesday will be warmer across the board with mid 60s to
lower 70s. The lastest forecast from the RAP smoke model suggests
the upper level smoke plume from wildfires in Alberta will still be
overhead, giving the sky a hazy or milky look. Sfc high centered to
the southwest will promote enhanced southwest flow off Lake Erie and
eastern Lake Ontario. Buffalo and Watertown will see winds 10-15 mph
with gusts 20-25 mph. This pressure pattern will only favor
localized lake cooling (temps lowering into the 60s) along the south
shore of Lake Ontario.
Wednesday night, it could rain late at night across the North
Country. The chance is very low mainly due to extensive dry air
that remains in place. That said, there will be a compact
shortwave diving southeast across eastern Lake Ontario toward
southeast NYS late. Very small pops under 20 pct seem
appropriate for this type of setup with decent forcing but
limited available moisture. Otherwise, at least a weak return
southwest flow with high pressure drifting to the south will
result in temps 5-10F warmer than what occurs tonight.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
Main theme in short term is warmer and staying mainly dry. Shortwave
that brings the small chance of rain to North Country late Wednesday
night could lead to a shower over far eastern portions of North
Country on Thursday. Dry elsewhere with highs surging well above
normal into the lower to middle 70s. Temps near 80 for warm spots of
the Genesee valley. Coolest just northeast of Lake Erie and Lake
Ontario with onshore southwest winds.
Overall there is general consensus that stronger shortwave and sfc
trough drops across se Canada and northeast, New England Thursday
night into Friday. How far west this wave and front track is the
main question for the forecast. No qualms with slight chances
east of Lake Ontario late Thursday night into Friday as these
features move through. Temps will continue to warm with many
areas seeing highs at or above 80 though it will be slightly
cooler near the immediate Lake Erie and Lake Ontario shores.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A strong 500mb ridge will move into the Pacific Northwest and
the northern Rockies this weekend through next week. Mid-level
heights will be maximized at all hours based on the 30-year
climatology. A more common mid-level trough will remain over the
Northeast through early next week.
Initially, a shortwave trough in northwest flow aloft will move from
the Upper Great Lakes into the Ohio Valley Saturday. A warm front
will extend from the Central Plains to the Mid-Atlantic region. The
eastern Great Lakes region will be on the "cold" side with a chance
of rain showers across western NY into Saturday night. Dry
conditions are likely across north central NY.
It looks mostly dry Sunday into Monday night, however latest NBM
shows chances of showers probably because of the 00z EC/members. 12z
GFS, ECMWF, and Canadian are in agreement that a building high
from the north will preclude shower chances across the eastern
Great Lakes region. A sharper trough will approach the region
Tuesday and rain showers are possible Tuesday through Tuesday
night.
Temperatures begin above normal Saturday but then drop below normal
Sunday through Tuesday.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR flight conditions will prevail through Wednesday and beyond
across the eastern Great Lakes as high pressure remains centered
over the region. Expect nothing more than some high/thin cirrus and
a plume of smoke aloft, with the smoke coming from wildfires in
northern Alberta.
Southwest winds will increase to some extent Wednesday afternoon,
with gusts of 15-20 knots expected northeast of Lake Erie and Lake
Ontario including KBUF and KART.
Outlook...
Thursday through Friday...VFR.
Saturday and Sunday...Mainly VFR. A small chance of showers.
&&
.MARINE...
Winds will quickly diminish on the lower Great Lakes tonight as high
pressure settles overhead. Mainly gentle breezes will prevail
Wednesday and Thursday, with localized moderate winds of 10-15 knots
at the east end of Lake Ontario due to lake breezes. No risk of
Small Craft Advisories the rest of the week.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Hitchcock/JLA
NEAR TERM...Hitchcock/JLA
SHORT TERM...JLA
LONG TERM...HSK
AVIATION...Hitchcock
MARINE...Hitchcock/JLA
Area Forecast Discussion
National Weather Service Cheyenne WY
553 PM MDT Tue May 9 2023
.SHORT TERM...(This evening through Wednesday)
Issued at 400 PM MDT Tue May 9 2023
Current surface analysis depicts high pressure slowly sagging
southward into the Great Lakes throughout the morning and afternoon.
Off to the west, a shortwave trough dug to the southeast across
southeast Wyoming and into the Nebraska Panhandle. Active weather
pattern remains on track over the next 12 to 36 hours, with
increasing confidence of a vigorous Pacific storm system that is
progged push across the Intermountain West through to the High
Plains Wednesday.
For today and tonight, SPC continues to hold a marginal risk for
severe storms for a cluster of elevated thunderstorms expected to
develop in northeast Colorado and travel northward across the
Wyoming and Nebraska border. Looks like a two round event, with
early onset precipitation this afternoon and again later tonight. At
this time, cannot rule out a storm or two becoming stronger between
4pm and 9pm MDT. However, the stronger storms look a bit better in
the overnight hours from Cheyenne to the southern Panhandle. Looking
at the thermodynamic profiles for the overnight hours, RAP forecast
soundings remain on the high end, with up to 2000 J/kg of MUCAPE and
decent shear capable of producing strong to severe storms. HiRes
model guidance, including the HRRR, has come more in-line with
picking up on these features and having storm relative helicity
upwards to 150 m^2 s^-2. Main impacts with these storms will remain
with gusty to strong winds and hail. With that being said, forecast
tonight will be tricky, with models having a difficult time locking
onto a solution and continually pushing this convection further
eastward into the most southeastern portion of the CWA and moving
into central Nebraska by the early morning hours. As the forecast
currently stands, most impacts should remain across the southern
Nebraska Panhandle, with the HRRR coming more in-line with the
general model consensus and placing convection further to the east
and less in Laramie County.
Wednesday onward will remain a bit more active, beginning with some
low-level fog from some moisture advection late Tuesday night into
Wednesday morning. Forecast soundings, combined with HRRR surface
visibility, have less than 1/4 miles visibilities for Laramie
County and the majority of the Nebraska Panhandle. Higher confidence
for fog exists across the Panhandle, where overnight wetting rain
and upslope flow will aid in fog development. Should see fog persist
through the early morning hours, lifting to low stratus through the
late morning and maybe even into the early afternoon. Overall, foggy
conditions and low stratus will play a role tomorrow for convection
and if enough surface heating can occur. However, with enough mid-
level instability and MUCAPE in the 1500 J/kg or greater, any sort
of lift will likely break through those restrictions and allow
convection to occur. In addition will need to pay attention to the
nice boundary that will set up across southeast Wyoming, where clear
skies and differential heating are more likely to occur earlier in
the morning north of Laramie County.
Once again, looking at the thermodynamic profiles for Wednesday, the
SREF is indicating a high likelihood of CAPE values reach above 1000
J/kg for areas along and east of I-25, keeping the best
opportunities for impactful weather along the I-25 corridor and in
the Nebraska Panhandle. Forecast soundings are also pointing at a
more impactful system with better MUCAPE values hovering around 1500
to 2200 J/kg, steep 700-500mb lapse rate around 8.1C/km, effective
bulk wind difference at 45kts, good 0-3 km SRH, and the SHIP
parameter at 1.5. All in all, convective parameters remain favorable
between model runs for strong to severe thunderstorms for eastern
Wyoming and the Nebraska Panhandle. Therefore, severe weather will
remain possible tomorrow, with large hail, damaging winds, and heavy
rain being the most likely impacts. In addition, chances continue
for some organized rotating updrafts, which could produce a few
isolated tornadoes. As the previous forecaster mentioned, HiRes
model guidance has remained consistent with discrete cells earlier
in the day, becoming more organized line of storms as they push
eastward into the Nebraska Panhandle by the afternoon hours.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 400 PM MDT Tue May 9 2023
Very active weather conditions through the end of the week and into
the weekend. The main impacts are as follows:
* A strong weather system slowly moving through the area Wednesday
through Friday will continue to produce a heavy rainfall and
isolated severe storm threat on Thursday.
* Heavy snowfall is possible for the highest peaks Thursday through
Friday.
* Unsettled weather continues with daily shower and storm chances
continuing through the weekend.
The daytime hours on Thursday will be a complex transition period in
the evolution of the strong spring storm traversing the Rockies this
week. On the synoptic scale, a vigorous closed 500-mb low will be
moving across south central Colorado by 12z Thursday, producing lee
cyclogenesis at the surface ahead of it. The system will gain a
negative tilt as it pushes into a strong ridge to our east. This
will turn the flow southeasterly across much of the depth of the
atmosphere and continue to advect in impressive moisture to the
area. PW values of 0.5 to 1.0" will cover much of the area per
ensemble mean forecasts at 12z Thursday, increasing from west to
east. These numbers are unseasonably high, generally around the 97th
to 99th percentile of mid-May climatology. Instability and shear
look quite a bit weaker than Wednesday, but there still may be
enough to produce an isolated severe threat. Veering wind profiles
per GFS forecasts are most prevalent in the morning hours Thursday,
becoming more vertically stacked as the upper level low treks
eastward. Lapse rates in the 6 to 7 C/km range across the area are
also more marginal. The saturated, skinny CAPE profile suggests the
possibility for more of a heavy rainfall threat Thursday into
Thursday night. Generally still thinking this will play out as a
widespread stratiform rain with embedded convection scenario that
could produce locally heavy rainfall.
As the upper level low continues to wind up Thursday into Thursday
night, it will develop a defined TROWAL and substantial isentropic
lift on its northwest flank. One of the main pieces of uncertainty
with this component of the system is just how far west this lift
will extend. The GFS (with support from the hires models that go out
this far) depicts a tighter system with this dynamic lift mainly
confined to areas along and east of the Laramie range, whereas the
ECMWF has a broader system with dynamic lift extending further west
into Albany and eastern Carbon counties. This difference results in
substantially different QPF solutions for areas west of the Laramie
range, which would have implications on the rain-on-snow flooding
potential. Details on that threat can be found in the Hydrology
section below. This would also have implications for snowfall
accumulation on the higher peaks, as the drier scenario might keep
the Snowy range peaks below warning criteria. Held off on any
headlines due to this uncertainty, but ensemble means produce
warning criteria snowfall in the vicinity of Medicine Bow Peak, so
may need a Watch soon. However, the impacts may reduced owing to the
very high snow levels, such that these high totals may only be found
at 11 kft or higher.
Heading beyond into Friday and the weekend, we`ll see the system
weakening on Friday with northerly wraparound flow. Expect a chilly
and breezy day with on and off showers as the storm starts to decay
and become less organized. Could see some embedded thunder, but much
smaller lapse rates should keep this fairly isolated. Both major
ensemble systems have now converged on a widespread mean of 1.5 to
2.5" QPF across the area along and east of the Laramie range by
Saturday morning. However, due to mesoscale dynamics and the
convective nature, this is likely to be much spottier in reality,
with some areas potentially picking up 3" or more of rain, while
others may struggle to get to 0.5". As the main rainy period comes
in range of the hires models, these locality details may be able to
be refined in the coming days.
For the weekend and beyond, the pattern looks very messy. An
extremely strong ridge will start to build in over southwest Canada
this weekend and develop a Rex block pattern. By Sunday, models show
a piece of the decaying vort-max breaking off and retrograding back
westward underneath the block to the north. With weak steering flow
over much of the west, we`ll have a lingering unsettled pattern that
will continue produce daily chance for showers and thunderstorms as
weak vort-maxes meander around the western CONUS.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 545 PM MDT Tue May 9 2023
Several aviation hazards continue tonight, with the first round of
thunderstorms moving out now but a second likely to follow late
tonight towards early Wednesday morning. The first round of storms
has moved through Scottsbluff, and a quick round of rain with
thunder is likely at KAIA and KCDR in the next hour that may
produce MVFR to perhaps brief IFR conditions. These are likely to
miss KSNY, but lightning will be close by. A few showers and weak
storms will continue for a few hours after, before another round
of storms develops later tonight. Generally thinking this will
move through around 07z to 12z, so return a few terminals to VCTS
for portions of that period. This is most likely to impact KCYS,
KSNY, KBFF, and KAIA.
Additionally, southeast winds will bring in abundant low level
moisture tonight and may produce low clouds and fog Wednesday
morning. Hires models are fairly inconsistent with this
possibility, so don`t have very high confidence. The best chance
for IFR is at KSNY and KCYS, though category reductions are
possible at KLAR, KBFF, and KAIA also. By late morning, this
should lift/break and allow the atmosphere to destabilize for
another round of PM storms Wednesday. Hires models are showing a
fairly late show, so introduced another round of VCTS but starting
after about 20z at KLAR, and 22z further east.
&&
.FIRE WEATHER...
Issued at 400 PM MDT Tue May 9 2023
Minimal fire weather concerns throughout the week, with daily
chances for wetting rains through Monday of next week.
Thunderstorms will leave to gusty and erratic winds, combined with
a few lightning strikes with stronger storms. Forecast rainfall
amounts continually trend higher with most places with above
normal QPF expected.
&&
.HYDROLOGY...
Issued at 400 PM MDT Tue May 9 2023
Increasing hydrology concerns over the next few days as a warm,
slow moving, and waterlogged system approaches the area. The
Little Snake River remains at action stage at Baggs, cresting
just below minor flood stage this morning. This could be exceeded
as early as Wednesday morning after the snow melt from today flows
further downstream. The typical diurnal cycle crests in the early
morning hours at Baggs. Therefore, a Flood Watch has been issued.
In addition to the warmer temperatures, we have a significant
weather system approaching our area. Scattered to numerous
thunderstorms Wednesday night will come with very high snow
levels, with rain falling as high as 10,500`. While most of this
activity is expected to be further east, some wet storms could
move over the Snowy range where significant snowpack remains.
Rain-on-snow concerns increase through the day Thursday as the
system pushes impressive moisture content back into Carbon county.
While snow levels will be lower during this time, rain falling in
the 7500 to potentially as high as 9500` would be on a significant
lingering snowpack. Thus will have to monitor for increased runoff
and flooding. The most precipitation is expected along and east of
the Laramie range though, where snow is mostly long gone. However,
substantial precipitation rates could produce local flood concerns
Wednesday night through Friday morning. Most of this area remains
in drought though, which may temper (but not eliminate) hydrology
concerns to the east.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MRD
LONG TERM...MN
AVIATION...MN
FIRE WEATHER...MRD
HYDROLOGY...MN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
658 PM CDT Tue May 9 2023
...00Z AVIATION UPDATE...
.SYNOPSIS...
Issued at 249 PM CDT Tue May 9 2023
Surface obs plot shows primarily an easterly breeze across the area.
Satellite shows some low stratocu lingering in NW IL with plenty of
sunshine elsewhere aside from some high cirrus. Temperatures were in
the 60s and low 70s, with dew points mainly in the mid and upper 50s.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 249 PM CDT Tue May 9 2023
Key message: Quiet weather in the short term.
Tonight and Wednesday, high pressure located over the Great Lakes
along with upper level ridging will keep quiet weather across the
area. With mainly clear skies and light winds overnight, temps are
expected to settle into the upper 40s to mid 50s. HRRR continues to
struggle with bringing pcpn into the SW Wednesday, while the NAM
does. In going along with the prior forecast thinking, opted to
remove pcpn mention through Wednesday afternoon with dry easterly
flow in place. Highs will be 75 to 80 with clouds on the increase.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 249 PM CDT Tue May 9 2023
Key messages:
1. Active weather returns Thursday through Sunday
2. Dry conditions early next week
Discussion:
Thursday through Sunday, a slow to retreat high will continue the
southeast flow feeding some drier air into the area. This may hinder
the shower and storm chances into Thursday as warm advection induced
waves lift across the area. The current blend has slight and chance
POPS mainly west of the MS River. By Friday, a precursory low lifts
north into the area bringing likely or categorical POPs to the area.
The main low in the plains will be slow to move through the area,
bringing periodic increases in the rain chances through Sunday.
After a brief lull Saturday AM, rain chances increase again into the
likely category Saturday afternoon and night as the low finally
moves through the area. Lingering chance POPs are slated for Sunday.
Due to some model differences in timing and placement, POP and QPF
details will be refined as we get closer. At this time, the WPC has
the higher rain amounts to our SE for Friday and to our N and NE for
Saturday afternoon and night.
Monday and Tuesday, the blended forecast has dry conditions as a
large and sprawling high pressure area is expected to build into the
middle of the country.
Temperatures will be in the mid 70s to mid 80s through Saturday,
with a brief cool down into the upper 60s to mid 70s Sunday before a
return back into the low to mid 70s Monday and 75 to 80 Tuesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 658 PM CDT Tue May 9 2023
VFR conditions will continue throughout the TAF period, with some
scattered high clouds. Southeast winds continue, generally around
5 knots tonight.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...14
SHORT TERM...14
LONG TERM...14
AVIATION...Schultz
Area Forecast Discussion
National Weather Service Grand Forks ND
1000 PM CDT Tue May 9 2023
.UPDATE...
Issued at 1000 PM CDT Tue May 9 2023
THere are indications of low level stabilization, however there
has also been a trend towards increasing effective shear across
our south primarily due to higher mid level westerly winds (upper
portion of RAP profiles). There is still an axis of 500-1000 J/KG
MU CAPE which is helping maintain isolated thunderstorm activity
in our south this evening and due to the shear we have had one
stronger storm tracking over Ransom County (19-20 kft agl 50dz
core), and considering the freezing levels (around 9500 ft agl)
this storm is likely capable of 0.5-0.75" hail and at least a low
probability for gusts around 40 mph as the cores collapse. All
indications are that activity should eventually weaken due to
further stabilization, but for the next few hours there is still
a window for stronger (sub-severe) storms to develop in southeast
ND mainly south of I-94 (less shear and CAPE in MN).
UPDATE Issued at 655 PM CDT Tue May 9 2023
A more organized cluster of showers/embedded thunder is riding
along elevated nose of WAA north of stationary front in west
central MN towards our east. Better instability is in place south
of this front and west of our CWA, with less than 500 J/KG in our
area. Shear is increasing, but the loss of daytime heating will
play a role in decoupling, so while elevated instabilty lingers
organized convection is less likely. There have been a few gusts
in the 30-40 mph range where collapsing cored (15-20kft agl)
occurred, and pea size hail can`t be ruled out due to low freezing
levels. Still, the threat for that activity should end with
sunset/stabilization of the BL. Signal is CAMs still shows
sporadic showers tonight, but in the absence of more organized
forcing coverage may tend to remain isolated to widely scattered.
I made adjustments to better reflect current trends.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 237 PM CDT Tue May 9 2023
A warm/quasi-stationary frontal boundary off surface low pressure
centered over southeastern Montana/northeastern Wyoming continues
producing showers in parts of southeastern North Dakota. Expect
this low to wobble slightly in an otherwise relatively stationary
position through the period before merging with surface low
pressure out of Colorado Wednesday night. A few rumbles of thunder
are possible through this afternoon, although with limited
instability and not a ton of shear, organized thunderstorms and
severe weather are not expected at this time. Scattered shower and
thunderstorm chances will continue through the night tonight
before dry conditions prevail through most of the day Wednesday.
There is a little more question as to how things will evolve late
Wednesday afternoon through the night. Instability looks to
increase as southerly flow at the surface advects moister are into
eastern ND and western Minnesota. The result being boundary layer
dewpoints look to rise to the 50s Wednesday afternoon. Continued
WAA as the thermal ridge pushes eastward will help allow for
shower and thunderstorm development late Wednesday afternoon
through the evening primarily in far northeastern ND and northern
MN. It does seem there is enough instability (around 1500 J/kg
MUCAPE) and marginal shear (30 to 35 kts of 0 to 6 km bulk shear)
that perhaps a few strong to severe thunderstorms are possible.
This is especially true with the relatively low freezing levels
early in the warm season. The main threat in any severe
thunderstorms would be large hail up to the size of quarters.
.LONG TERM...(Thursday through Tuesday)
Issued at 237 PM CDT Tue May 9 2023
A warm season Colorado Low looks to propagate into the central
Plains during the day Thursday and stall out somewhere over eastern
Nebraska/South Dakota through Friday night. This will produce an
active period of weather with periodic showers and thunderstorms
producing moderate to heavy rainfall through Saturday night.
This is especially true in southeastern North Dakota and a tier
or two counties directly east into northwestern Minnesota. Expect
breezy winds as well, especially Friday and Saturday. Generally
speaking, severe weather doesn`t look likely with this system.
Although with moderate instability, can`t rule out some stronger
storms Thursday afternoon.
Once the system`s wheels stop spinning and it pushes off to the
east, multiple trailing surface highs look to bring drier weather to
the region through at least the day Tuesday. With the system
producing widespread cloud cover and rainfall, expect cooler highs
(mostly in the 60s) Friday and Saturday. Otherwise, expect above
average temperatures Thursday, as well as Sunday into early next
week, with highs mostly in the 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 655 PM CDT Tue May 9 2023
VFR conditions should prevail in eastern ND and northwest MN
through the TAF period, however there is still a signal for low
stratus development towards north central ND where winds are
showing to decrease and there could be a bit more clearing of
mid-high clouds (this would impact KDVL with MVFR/IFR). SHowers
and thunderstorms remain possible, but coverage is becoming more
isolated/widely scattered in vicinity of KFAR and KBJI lowering
confidence in impacts. We could rule out a few overnight showers
at other terminals as well (chances even lower). Otherwise, winds
will tend to be out of the southeast decreasing below 12kt with
sunset this evening (unless there is a shower).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...DJR
SHORT TERM...Telken
LONG TERM...Telken
AVIATION...DJR
Area Forecast Discussion
National Weather Service Green Bay WI
957 PM CDT Tue May 9 2023
Updated aviation portion for 06Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 233 PM CDT Tue May 9 2023
The low clouds were stubborn to exit central Wisconsin early this
afternoon while skies were partly cloudy across the north. Mostly
sunny skies were observed elsewhere. There were a few isolated
showers across Oneida and Forest counties. Temperatures as of mid
afternoon were in the 60s to around 70.
For the rest of the afternoon into early this evening, the HRRR
model picked up on the isolated showers across the north. Visible
satellite images did indicate agitated cumulus clouds in the
forementioned counties. Did add isolated showers to the forecast
from eastern Oneida, Forest, Florence, and northern section of
Marinette and Oconto counties. Basically followed the HRRR trends
into early this evening.
Attention for tonight turns the chance of showers and a few
storms and the potential for fog. Models are not having a good
handle on the convection across Minnesota this afternoon. A weak
ripple in the 500mb mean flow will move across northern Wisconsin
later tonight into Wednesday morning. Most unstable cape values
off the Rhinelander soundings were only a few hundred J/KG,
combined with mid level lapse rates around 6 C/KM could not rule
out a few claps of thunder. The Storm Prediction Center Day 1
Outlook has portions of northern Wisconsin in the general thunder
category. As for fog, increasing cloudiness tonight should turn
skies mostly cloudy. With the high clouds overhead, this should
keep the fog from becoming widespread dense like this morning.
Also, some drier air filtered into northeast Wisconsin. Continued
to mention fog in the forecast tonight.
On Wednesday, the weak upper level disturbance will move east of
the state. Any lingering showers or isolated storms should come to
an end during the morning. Any fog will burn off by mid morning. It
will become partly cloudy with highs in the 70s, of course cooler
near Lake Michigan.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 233 PM CDT Tue May 9 2023
Mean flow will see a fairly amplified flow in place at the
beginning of the extended period, with a broad upper ridge from
eastern CONUS up through the Great Lakes, and an upper low over
the eastern Rockies. As the upper ridge slowly breaks around the
end of the work week and into the weekend, the upper low will move
into the Central Plains, bringing an increasing chance for
precipitation. The timing of this precipitation remains in fairly
low confidence for the end of the work week into the weekend.
Wednesday night through Thursday...A fairly dry period should
still be in place for the Wednesday night period into Thursday
morning. A sunny start to the day combined with light southerly
winds will bring a fairly steady rise in temperatures, with highs
well into the 70s for most of the region. There will be small
chance for a stray shower or two, mainly across central or north-
central WI if diurnal destabilization proves sufficient, but with
little in the way of CAPE or upper support during the day, the
vast majority of the area will remain dry.
Thursday night into Friday...As the upper ridge begins to break
down and the low heads towards the region, a weak warm air
advection aloft will move into the region overnight Thursday into
Friday. At the same time, a fairly decent shortwave will cross
the northern portion of the ridge through Friday morning, possibly
passing over the area. This will be a low confidence portion of
the forecast, as the timing and placement of the shortwave are
uncertain. Thus, kept chance pops in the forecast for much of
Friday, but would expect a round of rain as the shortwave crosses,
with a decent dry period to follow for the rest of the day.
The weekend...Much like last weekend, the upcoming weekend will
have chances for rain both days, but significant dry periods can
be expected at times. Friday night, the upper low will be in the
upper Midwest but the surface warm front will be well south of the
area. At the same time, a Canadian high pressure system will be
situated to our north, between Ontario and Manitoba. How much dry
air this system can bring into our region and how fast the north
arrives in the Upper Midwest will dictate how quickly
precipitation returns to the region Saturday. For the most part,
would expect dry conditions for much of Friday night into Saturday
with rain holding off mainly to our south and west, before
moisture transport wins out and rain spreads over the region
sometime mid to late Saturday. Scattered rain then likely lasts
into Sunday morning before clearing out of the area by the
afternoon. All of this said, don`t cancel plans for the weekend
just yet, as many details still need sorting for the upcoming
weekend. For example, the Canadian model is much more aggressive
with the intrusion of drier and colder air over the weekend,
bringing almost completely dry conditions and cooler temperatures
rather than a round of rainfall.
Temperature-wise, whether by rain or the aforementioned intrusion
of northerly air, high temperatures are expected to decrease in
the days ahead, with the coolest day being Sunday with highs in
the 60s. In either case, return flow will bring back above normal
temperatures for early next week.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 951 PM CDT Tue May 9 2023
A weak upper level disturbance will bring a chance of showers to
mainly north central/far NE WI overnight into Wednesday morning.
A weak frontal boundary will linger across northern WI during the
afternoon, and may help trigger a few thunderstorms as daytime
instability increases. Confidence is too low to mention storms in
the RHI TAF.
Will be backing off a bit more on fog potential overnight, as
widespread mid-level clouds are expected to overspread much of the
area. Patchy MVFR/IFR fog will still be possible wherever breaks
in the clouds occur toward daybreak. Any fog that develops should
mix out between 13z-14z/Wed.
SCT-BKN cumulus/altocumulus will prevail across the forecast
area into late Wednesday afternoon or early evening, followed by
clear skies late in the TAF period.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM.....Eckberg
LONG TERM......Uhlmann
AVIATION.......Kieckbusch
Area Forecast Discussion
National Weather Service North Platte NE
619 PM CDT Tue May 9 2023
.SYNOPSIS...
Issued at 334 PM CDT Tue May 9 2023
Key Messages:
- Redevelopment of showers and thunderstorms are expected this
evening into the overnight, a few of which may be severe, with
large hail and damaging wind gusts being the primary threats.
- Severe weather is possible again on Wednesday, mainly across
the west, with the threat for large hail and damaging wind
gusts.
- On Thursday, the entire forecast area is within a Slight Risk
for severe thunderstorms, with the threat for large hail and
damaging wind gusts. An isolated tornado is possible.
- Excessive rainfall may lead to a localized flooding across the
area tonight through Friday.
- Warmer and drier conditions return across western and north
central Nebraska for Monday and Tuesday.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 334 PM CDT Tue May 9 2023
An area of showers and thunderstorms may move into the northwest
Sandhills this evening. Storms were currently developing to the
west of Scottsbluff.
Early this evening, the NAM indicates 0-3km MUCAPEs increasing to
1500-2500 J/KG across nwrn Kansas and swrn Nebraska. The NAM, GFS,
and recent runs of the HRRR support the development of elevated
showers and thunderstorms to initially develop across swrn
Nebraska by 03Z and lifting northward and becoming more numerous
north of I80 into the central Sandhills tonight. Abundant moisture
with PWATs as highs as an inch to an inch and a quarter combine
with a developing H85 low level jet. This will be supportive of
locally heavy rainfall. WPC day 1 has a marginal risk of
excessive rainfall which could lead to localized flooding all
areas south of Highway 2 and 91.
This activity is forecast to continue into Wednesday morning and
lessen with a considerable amounts of stratus during the morning.
Highs temperatures were lowered to the low to mid 70s. The upper
level low pressure system will advance across the Great Basin on
Wednesday, with a closed low at the base of the trough south of
the Four Corners by early Wednesday evening. This will cause the
upper flow to become south southwesterly. While there is a chance
for showers and thunderstorms Wednesday afternoon, the majority of
the CAMs show the bettered likelihood to be across southwest
Nebraska late afternoon.
Wednesday night, the upper low will advance into far northeast
New Mexico. The upper flow will become oriented nearly due south
to north. This will bring the potential for showers and
thunderstorms likely across the Central High Plains, including
much of western and north central Nebraska. Elevated instability
as high as 1500-2500 J/KG will persist overnight as PWATs continue
to range from an inch to an inch and a quarter. A Slight Risk for
severe thunderstorms is outlooked for areas west of Hayes Center
through Gordon with a Marginal Risk east to near Highway 183.
Large hail and damaging winds are the primary concerns, with an
additional risk of excessive rainfall which may lead to localized
flooding.
.LONG TERM...(Thursday through Tuesday)
Issued at 334 PM CDT Tue May 9 2023
Model consensus brings a negatively tilted trough and closed low
over southeast Colorado by 18z Thursday. This will bring the
greatest potential for severe weather, with SPC forecasting a
slight risk for severe thunderstorms across a large part of the
region. This includes all of western and north central Nebraska.
This prediction suggests a low-level southeasterly flow veering
to a more southerly direction at mid levels to support
organized/rotating storms, with risk for hail and locally
damaging wind gusts. An isolated tornado is possible.
As earlier bouts of rainfall potentially saturate areas of
western and north central Nebraska, additional rainfall Thursday
through Thursday night could result in runoff and localized
flooding. Model indicate that the heaviest rainfall will fall
Thursday afternoon and evening.
It should be stressed that with soil conditions still very dry in
many areas and drought conditions persisting, the confidence in
any flooding will remain below average.
A good chance for showers and thunderstorms Friday into Friday
night as the upper level low lifts slowly northeast, initially
from southwest Nebraska into northeast Nebraska early Saturday
morning.
A broad upper trough will persist across the region Saturday and
Sunday with chances for showers to linger. Temperatures will
remain on the cool side in the 60s.
Dry and warming up Monday and Tuesday into the 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 620 PM CDT Tue May 9 2023
For the KLBF terminal: The evening hours will be fairly quiet with
some scattered high clouds. After 05z, thunderstorms will be
possible into the overnight hours. The strongest storms are
expected from 05 to 08z tonight. Ceilings will fall to MVFR after
midnight, then IFR toward daybreak Wednesday. Skies will remain
broken to overcast into Wednesday with ceilings increasing to 2000
to 3000 FT AGL by afternoon. For the KVTN terminal: Expect
scattered high clouds into the early overnight hours with ceilings
falling off to the 5000 to 8000 FT AGL range after 11z. There will
be a slight chance for isolated showers around sunrise Wednesday.
A thunderstorm or two may be possible as well. ATTM, the threat is
too low to be included in this TAF issuance.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Roberg
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...Buttler
Area Forecast Discussion
National Weather Service Nashville TN
733 PM CDT Tue May 9 2023
...New UPDATE...
.UPDATE...
Issued at 729 PM CDT Tue May 9 2023
Mostly clear skies have settled over Middle Tennessee and tonight
looks to bring us a welcome reprieve from the storminess of the
past two nights. The atmosphere is much drier than 24 hours ago,
with PWAT having decreased to 0.81 inches and the K-index down to
11 from the 29 we observed this time last evening. A surface
boundary is draped over the Tennessee Valley to our immediate
south, and so we find ourselves on the dry side with a pleasant
north wind. Current forecast is in good shape, so no changes are
planned this evening.
&&
.SHORT TERM...
(This afternoon through Thursday Night)
Issued at 151 PM CDT Tue May 9 2023
Frontal boundary is slowly working southward across the mid state
this afternoon. GFS, Euro and Hrrr solutions continuing to lean the
way of atmospheric capping. The NBS solution, however, suggests
reaching our convective temperatures success across our south by
late afternoon. Latest f-builder info keeps the low pops going
across our south until evening.
It`s quite humid out and there would ordinarily be some concern for
overnight fog tonight. However, some drier air from the north will
win out with falling dewpoints expected. Dry weather will continue
into Wednesday and will be paired with some modest ul ridging. The
ridge will be rather progressive and on it`s heels will be an
approaching shortwave. This feature will be our next weather maker
as the axis slowly approaches from the southwest. Looks like a
chance of showers and thunderstorms will reenter the picture by
Thursday afternoon and will continue into Friday.
As for any severe potential, despite decent instabilities, the low
level energy and the phasing of any stronger forcing is not there.
Looks like general thunder for now. Rainfall amounts do not look
troublesome , either. You can expected one quarter to one half inch
for most areas.
For the near term temperatures, heights will be running on the high
side with some ridging effects noted at times. looks like our
numbers will run a good 5 to 10 degrees above normal. &&
.LONG TERM...
(Friday through next Tuesday)
Issued at 151 PM CDT Tue May 9 2023
In the extended forecast, some weak ridging will come back into play
on Saturday and through the weekend. Some degree of moisture
undercut will still be apparent, particularly along and north of the
mid state. Convective pattern will likely morph to afternoon and
evening bias given the ridge effects. Cape to cap ratios will
still promote afternoon development.
Looks like a frontal system will approach by Tuesday with a modest
associated shortwave as well. Pops will continue with a little more
in the way of nocturnal activity possible.
Not seeing any severe pot with the frontal system. Organization is
ok, but forcing looks weak. Instability phasing looks poor and thus,
looks like general thunder. Qpf totals look like a quarter to a half
of an inch.
Extended temps look warm and muggy and we may approach 90F over the
weekend. The Tuesday post frontal view looks like a return to more
seasonal levels.
&&
.LONG TERM...
(Friday through next Tuesday)
Issued at 151 PM CDT Tue May 9 2023
In the extended forecast, some weak ridging will come back into play
on Saturday and through the weekend. Some degree of moisture
undercut will still be apparent, particularly along and north of the
mid state. Convective pattern will likely morph to afternoon and
evening bias given the ridge effects. Cape to cap ratios will
still promote afternoon development.
Looks like a frontal system will approach by Tuesday with a modest
associated shortwave as well. Pops will continue with a little more
in the way of nocturnal activity possible.
Not seeing any severe pot with the frontal system. Organization is
ok, but forcing looks weak. Instability phasing looks poor and thus,
looks like general thunder. Qpf totals look like a quarter to a half
of an inch.
Extended temps look warm and muggy and we may approach 90F over the
weekend. The Tuesday post frontal view looks like a return to more
seasonal levels.
&&
.AVIATION...
(00Z TAFS)
Issued at 627 PM CDT Tue May 9 2023
VFR conditions are expected at BNA/MQY/CKV for the taf period.
There could be a period of MVFR fog at CSV/SRB after midnight and
that was addressed with a tempo group. NNE winds will decrease
below 5 kts this evening at all taf sites. Winds will increase to
5-10 kts out of the ENE on Wednesday by mid morning. Observations
from MQY are not being received so AMD NOT SKED was included at
the site.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 60 86 64 85 / 0 0 20 60
Clarksville 58 84 62 83 / 0 0 20 60
Crossville 53 80 57 78 / 0 0 10 30
Columbia 59 86 63 82 / 0 0 30 60
Cookeville 55 82 61 81 / 0 0 10 30
Jamestown 52 81 57 80 / 0 0 10 30
Lawrenceburg 59 85 64 81 / 0 0 20 50
Murfreesboro 57 86 62 83 / 0 0 20 50
Waverly 59 85 62 83 / 0 0 20 70
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Rose
SHORT TERM...21
LONG TERM....21
AVIATION.....Reagan
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
815 PM EDT Tue May 9 2023
...New AVIATION...
.DISCUSSION...
Issued at 241 PM EDT Tue May 9 2023
Broad, zonal flow with weak upper-level ridging remains in place
today across the region. In response to surface high pressure off
to the east, the surface flow also remains easterly in response.
With the surface high now stretched even farther than it was
yesterday, this flow has been really light. With the light flow, the
sea breeze boundary is becoming quite evident on satellite
imagery and beginning the eastward march. Simultaneously, the east
coast sea breeze is doing the same thing, but trekking westward.
A couple brief showers developed along the west coast sea breeze
already, and it wouldn`t be surprising to see a couple more.
Latest RAP analysis and ACARS soundings from TPA show PW values
around the Bay Area and points northward have increased to right
around 1.5 inches this afternoon. Atmospheric profiles today do
indeed show an atmosphere with additional moisture, compared to
yesterday.
Other than a couple showers today, the bigger potential for storms
starts to creep in tomorrow across the Nature Coast and the Central
FL interior. Ahead of a weakening frontal boundary, moisture is
expected to continue pooling in this region. As the additional
forcing near the boundary combines with additional low-level
forcing from diurnal sea breeze collisions, some thunderstorms
are likely across this region. Looking at forecasted mid-level
temps and atmospheric profiles, conditions look to favor some
potentially stronger storms, with small hail and/or strong gusty
winds with storms not out of the question. A more continental
upper-level airmass, which is a little cooler and drier than the
typical airmass in summer, is the culprit for such a potential as
this.
Tomorrow doesn`t look like it`ll be the last day for stronger storms
either. While the subtropical ridge begins to settle in at the
surface, the upper-level flow hasn`t completely flattened yet. Some
weak upper-level disturbances continue to propagate across the FL
peninsula through the week, aiding vertical ascent into a more
continental airmass aloft. Given additional low-level moisture and
instability, this continues to keep at least some potential for
thunderstorms in the forecast for the days to come. Any storms
that tap into the mid-levels have the potential to be stronger
than most storms that form in July for instance. The most
widespread coverage currently looks to be Thursday as the moisture
axis shifts a little farther south, with lower rain chances
thereafter. So while storms are possible each day, generally not
expecting the same coverage most days that one would expect in
another few weeks.
Regardless of storms, it is going to be pretty warm. With easterly
flow prevailing (and getting a little stronger for the next couple
days with the weak front in the vicinity), the highest temperatures
are probably going to end up being fairly coast to the FL West
Coast. This is because the sea breeze is likely to be slow to get
going and have limited inland progression. Over the next week,
that is really not going to change much either.
So overall, warm (if not hot) weather continues. Isolated to
scattered storms, some of which could be on the stronger side, are
possible each day.
&&
.AVIATION...
(00Z TAFS)
Issued at 813 PM EDT Tue May 9 2023
VFR conditions expected through the period with west to northwest
flow. Chance of storms inland tomorrow with a PROB 30 added to LAL
late in the TAF period.
&&
.MARINE...
Issued at 241 PM EDT Tue May 9 2023
Easterly flow continues for the most part, except during the
afternoon hours nearshore where a sea breeze is likely to develop.
A slight increase in the easterly winds is possible during the
overnight hours as resistance from the sea breeze wanes. Some
thunderstorms could develop across inland areas and move towards the
coast each day. While winds are generally expected to be less than
15 knots and seas are expected to be two feet or less, locally
hazardous conditions are possible in the vicinity of thunderstorms.
&&
.FIRE WEATHER...
Issued at 241 PM EDT Tue May 9 2023
Relative humidity values continue to increase as additional low-
level moisture moves into the region. Thunderstorms begin to
return to the forecast beginning as early as tomorrow across the
Nature Coast and interior, shifting south and west somewhat for
the duration of the week. No significant fire weather concerns
exist for the next few days, other than to note the potential for
some fog tomorrow morning across the Nature Coast, and gusty and
erratic winds in the vicinity of any storms that develop.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 72 92 74 91 / 0 20 10 50
FMY 72 94 74 94 / 0 10 10 60
GIF 69 95 71 91 / 0 30 20 60
SRQ 70 91 72 91 / 0 10 10 50
BKV 64 94 67 93 / 0 30 10 60
SPG 74 89 75 89 / 0 10 10 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
DISCUSSION/AVIATION/MARINE/FIRE WEATHER...Shiveley
DECISION SUPPORT...Giarratana
UPPER AIR/CLIMATE...Giarratana
Area Forecast Discussion
National Weather Service Topeka KS
606 PM CDT Tue May 9 2023
.UPDATE...
Issued at 606 PM CDT Tue May 9 2023
The cold pool as pushed through the forecast area with the outflow
boundary into Wichita and just to the east of the forecast area. A
cool, turned over airmass remains over the forecast area. Models
eventually want to redevelop southerly low level flow with some
moisture return, but based on current obs it appears they are to
aggressive with the return flow. The concern is for a
redevelopment of elevated storms later tonight. Think there may be
several hours before deep moist convection could redevelop with
only some light showers that are currently passing over central
KS. The HRRR is showing potentially around midnight or shortly
after for this potential mainly over north central KS where the
nose of the low level jet may affect. The meso high will keep
some gusty winds in play for a few hours this evening. But overall
the expectation is for the weather to quite down for the early
evening.
&&
.DISCUSSION...
Issued at 324 PM CDT Tue May 9 2023
Forecast summary:
- A line of storms continues to move from West to East across the
area and should exit or otherwise weaken by this evening.
- Chances for showers and storms continues off and on through
Wednesday.
- Thursday brings another possible round of severe storms across the
area. However, only low to medium confidence that afternoon storms
develop very far north into the area.
Forecast thoughts:
Currently, an upper ridge axis is situated from the upper MS Valley
region through the Mid MS Valley region. A Pacific trough is digging
into central and southern California resulting in southwest flow
from the Desert Southwest into the northern Plains before reaching
the apex of the ridge to the east. The main feature impacting the
forecast area for the balance of the afternoon into part of this
evening is a line of severe storms advancing from west to east and
gradually turning southeast. Some portions of the line have begun to
weaken as instability and shear to the east is generally less
conducive to support robust updrafts. Impacts to be on the look out
for through this evening will still be mostly damaging winds and a
few updrafts capable of producing large hail. Have seen a few
embedded tornadoes but this generally is less favorable
environmentally as the storms move east. Could also be a brief
window for a flooding threat over portions of east central Kansas
where storms earlier this morning produced some heavy rainfall.
Into Wednesday, a break from the severe weather is more certain as
upper ridging ahead of the Pacific trough builds over the area. A
few showers and storms may still form within residual moisture
across the area with daytime heating. These should be more like
summertime convection will little shear in place. Some areas may
see beneficial rainfall if showers and storms form.
Thursday is the next day of potential severe weather across the
area. The timing of the upper low lifting into the region from the
West will determine when the overall forcing for ascent overlaps
with the best instability as well as shear to support severe
updrafts. Right now, still looks like the overall negatively tilted
trough/upper low is slowing a bit. This could allow for a better
setup for storms into the afternoon to fire with upper level support
off the dryline over central Kansas vicinity. However, if forcing is
strong enough early morning isentropic ascent could allow for broad
coverage of showers and storms. If these linger then instability may
not be as great into the afternoon over the area. Some guidance is
hinting at this potential and the focus for stronger storms could
remain just to the south of the area over south central Kansas into
Oklahoma. Still low to medium confidence so the focus for storms
will be highly dependent on mesoscale set up going into the day and
how that interacts or is otherwise augmented by the synoptic
features.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday)
Issued at 606 PM CDT Tue May 9 2023
Rain should continue to move out of the TOP and FOE terminals
shortly after 00Z. Models are suggesting to potential for some low
clouds with increasing boundary layer RH, but confidence in this
is low with the expectation for some mixing. There will continue
to be some mid and high clouds though. Winds should subside in the
next hour or two becoming more southeasterly.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Wolters
DISCUSSION...Drake
AVIATION...Wolters