Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/08/24
Area Forecast Discussion
National Weather Service La Crosse WI
950 PM CDT Tue May 7 2024
.KEY MESSAGES...
- Scattered storms into the evening, mostly along and east of the
Mississippi River. A few could be strong with small hail, gusty
winds...but can`t rule out a funnel cloud or two in western WI.
- Active weather pattern with a series of shortwave troughs
promising periodic rain chances into next week. Severe threat looks
low. Rainfall from today through next Thu could reach 1 1/2 to 2".
- Cool Thursday, mostly around the seasonable normals after that.
&&
.DISCUSSION...
Issued at 210 PM CDT Tue May 7 2024
OVERVIEW: wagon train of upper level shortwaves are looking to drive
across/near the upper mississippi river valley through the weekend,
and much of next week. While there are some differences in
timing/placement of the upper level features in the GEFS and EPS,
they both agree the pattern should stay "active". There doesn`t look
to be much/if any tap to gulf moisture after today, but the model
blend suggests amounts (including today) upwards of 1 1/2 to 2"
through next Thu. A 10 to 20% to exceed 3" for a few locations.
After today, instability is looking meager through the period for
most days, keeping any severe threat low (to none).
REST OF THE AFTERNOON/TONIGHT: Additional Showers & Storms This
Afternoon and Evening
As our morning line of storms continues to exit the region, clearing
skies with occasional bands of low-level clouds on GOES-16 visible
satellite imagery can be noted pivoting around a clearly defined low
pressure center. As we continue through the afternoon, clearing
skies will allow for destabilization to take place with the 07.15z
RAP ramping up MLCAPE values to around 1000-1500 J/kg later into the
afternoon. As of 1830z, satellite imagery shows some aggravated
cumulus with a few weak convective cells popping up east of the
Mississippi River. While the instability later today is fairly
conducive for convection, however, 0-6km bulk shear profiles (around
10 kts) in the CAMs would suggest a more pulse storm environment. In
short, expecting cells to develop quickly when any localized surface
boundaries are utilized but will struggle to maintain their cores
aloft. Consequently, there may be some small hail and gusty winds
with the most robust updrafts when considering relatively low
freezing levels to around 8kft. With surface flow changing to
southwest by 21z, will have to watch for some non-supercell
funnel/tornado threat as 0-3km CAPE approaches 300 J/kg. Therefore,
the RAP increases the non-supercell tornado parameter substantially
for a few hours this afternoon and evening. Currently, the CAMs
suggests showers and storms to move northeast with the mean wind
through the later evening hours and weaken as instability wanes.
WED AFTERNOON/THU: an occlusion still set to lay northwest of its
parent sfc low tracking east across the Ohio River Valley Wed
afternoon/evening. A loft, shortwave energy set to spit east from
the plains while a ripple in the upper level flow drops southward
out of Canada. The features will interact to spark areas of showers
- mostly favored along/south of I-90. These will sink
south/southeast with the shortwave movement/exit of the sfc trough
Thu. Meager instability with the bulk of the deep layer shear farther
south. Some turning in the the lowest 0-1km per RAP bufkit
soundings, and there is sfc convergence along the occlusion. With a
cold core upper level low association, there does lie some low end
risk for tornadoes near the sfc convergence Wed afternoon. Overall,
the bulk of the severe threat lies south of the local area.
FRIDAY: the long range guidance has been in good agreement with
taking a shortwave trough out of southern Canada south/southeast,
dropping it across the upper mississippi river valley Fri
afternoon/evening. Weak low level warming and a little Fgen will
help the feature spark another area of showers as it spins across
the region. 250-500 J/kg of SCAPE in the GFS and NAM support some
scattered thunder chances while deeper shear is displaced to the
west. No severe expected at this time. With no southern tap to deep
moisture, rainfall amounts trending less than 1/4".
SUNDAY/START OF NEXT WEEK: more bits of upper level energy currently
progged to slip across/near the region in the GEFS and EPS, bringing
additional rain chances. Some differences in timing and location,
but the long range guidance keeps it active and potentially wet
through the middle part of next week.
TEMPS: Thu still trending to be the coolest day of the week with an
upper level trough dropping across the region - bringing colder air
along with cooling from areas of rain. Probabilities in the LREF sit
at 10-20% to warm out of the 50s - although the EPS is a bit more
optimistic that a few locations could break 60 degrees.
After that, the EPS and GEFS settle in to temperatures plus/minus 5
to 10 degrees around the seasonable normals.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 950 PM CDT Tue May 7 2024
A brief shower remains possible for a few hours late this
evening. Otherwise, VFR conditions are likely into Wednesday
with patches of mid/high clouds and winds under 10 kts. Chances
for showers and isolated storms will increase later
Wednesday/Wednesday night, but with lower confidence in
placement of the rain at this time, will not explicitly mention
at this point, but may be needed in future updates.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor/Rieck
AVIATION...JM
Area Forecast Discussion
National Weather Service Columbia SC
1038 PM EDT Tue May 7 2024
.SYNOPSIS...
A brief lull in thunderstorm activity is anticipated through
early Wednesday, with increasing chances of showers and storms
towards the end of the week. Potential for strong to severe
storms will exist on Thursday and Thursday night ahead of an
approaching cold front. Drier conditions return for the weekend.
Expect generally above average temperatures through the latter
half of the week before transitioning to near or slightly below
average during the weekend.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
A weak shortwave aloft continues to move through the primary
mid-level ridge axis which is triggering some scattered strong
thunderstorms across western and central NC. A broad cirrus
shield aloft continues to push over our area, south of the deep
convection and as of 00z, our cumulus deck has completed
dissipated; instability across SC is generally limited and will
only continue to drop more over the next few hours. So based on
the current water vapor imagery, radar, and hi- res guidance,
the best forcing from this shortwave should continue to remain
north of our area, across NC, with broad height rises thanks to
the ridge positioning. So PoP`s are falling off quickly and
confidence in any showers-storms in our area is low. The only
question of note is the deeper convection-MCS back across GA,
which is not being handled well by the hi-res guidance. The
general steering flow aloft is turning more northwesterly on the
back-edge of the shortwave around the ridge axis which may
allow this MCS to move into eastern GA. But CIN rapidly
increases and instability drops off quickly across eastern GA,
so even if the complex does sustain eastward, severe potential
is low overall.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Active short term period is on tap, with multiple chances for
potential severe weather. This threat is primarily centered on
Thursday, where damaging winds and large hail are possible with
strong thunderstorm development.
09z RAP forecasts a fairly complex, expansive 500 hPa trough
centered across the central Plains with a shortwave trough exiting
into the northeastern US followed by another emerging into the
central Plains south of the center of the low. Ridge axis is
forecast to be atop the Carolinas, shifting eastward through the
day. Recent CAM guidance has begun to show a leftover MCS
progressing eastward across the TN Valley towards the Appalachians
by 12z. There is quite a bit of uncertainty surrounding this, but we
will address that momentarily. As the ridge axis shifts eastward it
will be followed by a strong, zonal southern stream 250 hPa jet
streak with the left exit region emerging over the central Carolinas
by 00z Thursday. As southwesterly flow increases, an EML with 7-7.5C
500-700 hPa lapse rates will push over northern SC and southern NC,
yielding 2000+ j/kg of MLCAPE across the northern FA as early as
18z. Soundings are quite impressive, with EML and deep layer shear
supportive of potential severe convection.
Large scale forcing is primarily going to be focused to our
northwest across the OH Valley, leaving some question marks as to
whether or not we actually are able to see convection initiate in
the northern FA. The severe risk is definitely conditional, which is
why it is important to note the spread amongst guidance as to
whether or not a convective system makes it to the Appalachians
tomorrow morning. Forecaster confidence will increase in potential
severe convection tomorrow afternoon if an outflow boundary from
decaying convection makes it into western NC. This would be able to
focus low-level forcing to initiate convection into the favorable
thermo environment across the northern FA. But until details become
more concrete, it is hard to say whether or not we`ll certainty see
convection tomorrow up there. Low-end Chance PoPs seem appropriate
at this point. Highs will be quite warm given nice southwesterly
flow at the surface, so look for highs in the lower 90s.
Wednesday night through Thursday night looks very active, with
higher confidence in at least a couple rounds of potentially severe
convection. MLCIN will likely settle in across much of the forecast
area after 11p Wednesday, allowing much of the convective threat to
shift north of the forecast area. Then we turn our attention to the
northwest. Boundary layer moisture is expected to remain rich, with
steep mid-level lapse rates helping maintain easily accessible
instability ahead of an expected line of convection approaching from
the west. Most pieces of guidance show this crossing the
appalachians Thursday morning and decaying in western NC. Ahead of
this, it is likely that capping over our forecast area should help
to keep any prior convection at bay and allow for significant
destabilization to develop - potentially on the order of 2000+ j/kg
of MLCAPE again. The question is again whether or not convection
initiates during the afternoon hours. Cold front will slowly
approach the region through the afternoon. While there doesn`t look
to be significant synoptic support across the area, both the GFS and
NAM are showing a 700 hPa shortwave pushing across the Carolinas.
Combine that with moderate instability with the surface cold
front/remnant outflow boundary and the thinking is that convection
will be more widespread than either model is currently showing
during the afternoon hours. Temps should get into the mid 80s ahead
of the convection.
Another round of convection is possible on Thursday night, which may
be the highest confidence this forecaster has in any of these
rounds. The cold front looks as if it will continue to slowly move
southward and almost stall across the area by Thursday night, with a
strong shortwave pushing atop this with high MUCAPE values along and
south of the front as the shortwave pushes eastward. This should
yield at least widespread, elevated convection that will likely push
into the area late Thursday night and early Friday. Uncertainty
abounds about this given the uncertainty during the day on Thursday,
so it is hard to comment on the potential severity of the
convection. However, a severe risk certainly looks to continue
into the overnight hours on Thursday as elevated instability
will likely remain in place. So to summarize: forecaster
confidence in several rounds of convection is moderate, with
overall confidence increasing with each time step from Wednesday
to Thursday to Thursday night. SPC has a Marginal Risk in place
tomorrow and a Slight Risk on Thursday, which makes sense given
uncertainty regarding both days. Given the widespread
instability expected across the area, severe convection is
definitely possible in each of these rounds. Clarity will be
added over the next 24-36 hours as more model guidance takes
what actually happens into account.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Won`t spend a ton of time focused on this considering the
threat for convection on Wednesday and Thursday. It does look
like the front will slowly push through the area on Friday, with
drier air and high pressure filtering into the region over the
weekend. Showers and thunderstorms are likely to to push
eastward and out of the area during the day on Friday. Really
tough to discern whether or not this convection will be severe
given the uncertainty preceding it, but it is possible that more
strong storms occur on Friday. Temps will likely return back
towards normal, with highs in the low to mid 80s through much of
this period. Guidance shows dry weather through early next week
before moisture and southwesterly flow return early next week
and offer up more substantial rain chances by Tuesday or
Wednesday.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
High confidence in VFR conditions through the forecast period.
No convection to worry about this evening with cumulus
dissipating with the loss of heating, although cirrus shield
continues to slowly move overhead through the early overnight
hours. A 25 knot low level jet should help keep the boundary
layer mixed and surface winds in the 3 to 5 knot range overnight
which should help preclude fog concerns.
Winds should pick up to around 10 knots by 15z from the
southwest as deep southwesterly flow develops with low pressure
moving into the Ohio Valley with afternoon convection expected
to remain mainly north of the terminals.
EXTENDED AVIATION OUTLOOK...Active weather with mainly diurnal
convection each day through Friday. There`s potential for more
widespread severe storms on Thursday. Brief CIG/VSBY restrictions
and gusty winds may accompany any thunderstorms that affect the
terminals.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
Forecast Discussion at weather.gov/mqt.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
MARINE...Small Craft Advisory until midnight CDT tonight for LSZ140>146.
&&
$$
DISCUSSION...Wolfe
AVIATION...Britt
MARINE...Wolfe
Area Forecast Discussion
National Weather Service Peachtree City GA
800 PM EDT Tue May 7 2024
...New 00Z Aviation Discussion...
.SHORT TERM...
(This afternoon through Wednesday)
Issued at 248 PM EDT Tue May 7 2024
Large 500 mb low is cut off and located over the northern Great
Plains becoming increasingly vertically stacked with surface low in
same area. This storm system was responsible for the severe weather
in the Plains last night, and the organized convection from that has
progressed well ahead of a now stalled cold front and mostly fallen
apart as it pushes through the eastern CONUS. Some convective debris
from that has been traversing the area, and when combined with some
AVA aloft from shortwave ridging, has prevented us from taking off
convectively this afternoon. This is changing into the evening, and
leftover boundary from overnight convection is pushing in, which
could provide a focus from some afternoon showers or thunderstorms,
though expecting these should be very isolated, with best chances to
the north over the higher terrain.
Tonight, moisture continues to push into the area. Some convection
may push in from the west, dependent on whether or not it can get
going over parts of Alabama. North Georgia would be the most likely
to see this per hires guidance. There is a small chance some of this
could be severe for a brief period in far NW GA, as the parameter
space there has decent instability with 40-50 kts of effective bulk
shear. A Marginal Risk (1 out of 5) is in effect for far NW GA as a
result. With sunset, any convection remaining should become
increasingly elevated.
Tomorrow, some hires guidance shows some convection taking place
across northern GA that should be under severe limits, but may have
impacts on overall evolution of convection later in the day.
Guidance shows a piece of the upper level low over the Plains
breaking towards the eastern CONUS as a potent shortwave, allowing
for PVA and decent shear across the CWA Wednesday evening into
Wednesday night. Some general afternoon storms will be possible, but
the bigger "show" may be later in the night and into early Thursday
as a line of storms pushes into northern GA. HRRR and a few other
hires members from this morning show very organized convection with
some UH tracks. This tracks with the parameter space forecasted -
HREF means show MUCAPE of 500-1000+ J/kg still over northern GA by
the early morning hours with 30-40 kts of sfc-500 m shear,
representative of substantial shear within the low levels. This
leads to nearly 100-200 m2/s2 of 0-1 km SRH, which would allow for
ingestion of streamwise vorticity for potential updrafts. Want to
emphasize however that uncertainty remains in how this will evolve -
convective evolution today through tomorrow will have a large
influence on the evolution of the upper levels through diabatic
forcing and the low levels via outflow and other factors. The
environment will be there - it remains to be seen whether any storms
will be able to utilize it.
Lusk
&&
.LONG TERM...
(Thursday morning through next Monday)
Issued at 248 PM EDT Tue May 7 2024
Highlights:
-Potentially active weather will be ongoing at the start of the long
term persisting into Friday.
-Drier weather returns by the weekend persisting into early next
week.
No significant changes with this latest forecast. Still targeting
primarily two rounds of severe potential: the first Wednesday night
into Thursday morning for North GA (1-20 northward) and the second
Thursday evening through early Friday morning for Central Georgia
(south of I-20).
A low pressure system and attendant cold front will be pushing
eastward across the Ohio/TN Valley Regions. This will drive a
complex of showers and thunderstorms, ahead of the front, into the
northern sections of Georgia Thursday morning. Latest hi-res
guidance appears to be slightly quicker with moving this complex
into North GA Thursday morning. The primary threat with any strong
to severe thunderstorms still appears to be damaging winds as a
result of decent deep layer shear and lapse rates accompanying the
complex. Hail and possibly an embedded spin-up tornado are still
threats as well.
This activity will gradually push south through the morning on
Thursday and the question remains if the complex will weaken and/or
be the focus for possible redevelopment during the afternoon as peak
heating occurs. As a reiteration, model guidance typically
struggles with the evolution of convective complexes, thus, still
accounting for some level of uncertainty as far as exact placement
of convective activity beyond Thursday morning. The surface cold
front will still be moving through the forecast area and an
additional surface low looks to develop across the Lower MS
Valley. Latest runs of the 12z hi-res guidance is still picking up
on an additional complex of showers and thunderstorms developing
and translating eastward towards the area Thursday night into
Friday. Again the biggest question will be how this evolves as it
progresses towards the area. Lift from the front, decent lapse
rates, plenty of wind energy in the mid/upper levels accompanying
the main trough may support yet another (third) severe risk late
Thursday into Friday for Central Georgia. Damaging winds and hail
will be the primary hazards for any strong to severe thunderstorms
that develop during the afternoon Thursday or in the evening
through the overnight period. Tornado threat is still fairly low
at this time. Stay tuned for additional updates...
The surface cold front will start to clear the area pushing any
lingering rain/thunder chances out of the forecast area by Friday
afternoon. We return to NW flow aloft with a brief cool down just in
time for the weekend. Some low chance PoPs have been introduced for
next week as some mid-level disturbances look to move through flow
aloft.
07
&&
.AVIATION...
(00Z TAFS)
Issued at 752 PM EDT Tue May 7 2024
Scattered shower and thunderstorm activity will continue in
far northern Georgia through 06Z Thursday. Storms are not
expected at any of the TAF sites during this period, but some
drizzle is possible between 10Z and 15Z Wednesday. A mix of IFR
and MVFR ceilings (cloud bases 600-2500 ft AGL) should develop in
the region between 06Z and 17Z Wednesday. Southerly to
southwesterly winds will continue through 06Z Thursday. The
strongest winds, 6 to 12 kt, should occur between 15Z Wednesday
and 00z Thursday.
//ATL Confidence...00Z Update...
Overall confidence in the KATL TAF is moderate.
High confidence in the wind, visibility and precipitation
forecasts.
Low confidence in the ceilings between 08Z and 12Z Wednesday.
Albright
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 68 88 69 84 / 10 30 40 80
Atlanta 69 87 69 85 / 20 30 50 90
Blairsville 64 82 63 78 / 40 60 80 90
Cartersville 67 87 66 83 / 30 40 60 80
Columbus 70 91 72 89 / 10 20 20 80
Gainesville 69 86 69 82 / 30 50 60 90
Macon 69 90 70 89 / 0 10 10 70
Rome 68 87 67 85 / 40 50 70 90
Peachtree City 69 89 69 86 / 10 20 30 80
Vidalia 69 92 71 92 / 0 10 10 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Lusk
LONG TERM....07
AVIATION...Albright
Area Forecast Discussion
National Weather Service Grand Forks ND
924 PM CDT Tue May 7 2024
.KEY MESSAGES...
- A line of weak thunderstorms will continue north this afternoon
with the potential for gusty winds to 50 mph and small hail.
- Scattered rain chances return this weekend.
&&
.UPDATE...
Issued at 924 PM CDT Tue May 7 2024
Almost all the shower and storm activity has faded away now.
Cloud cover is still fairly thick, with just a few holes
scattered about. With the recent rain, any clear spot where the
wind becomes light could see some patchy fog. At the moment,
wind speeds should stay up just enough and it should remain
mostly cloudy.
UPDATE
Issued at 629 PM CDT Tue May 7 2024
Line of showers and embedded thunder continues to move north
this evening. The line currently is situated over Towner county
through northern Beltrami county. Over the past several hours it
has become unorganized and lost its intensity. SFC vorticity and
instability have started to weaken and will continue to do so as
we progress through the remainder of the evening hours. Isolated
gusts behind the front of 30-35mph will be possible through the
rest of the evening before we loose further daytime heating and
mixing potential.
&&
.DISCUSSION...
Issued at 242 PM CDT Tue May 7 2024
Storms continue to fire along the northward moving occluded front
and currently span from the Valley City to Fargo corridor and
southeast to Fergus Falls. These will continue to propagate
north/northwest as the front wraps around the upper low to the
southwest centered over the central ND/SD border. MLCAPE of 400-800
J/kg per latest RAP analysis overlaid upon the ample boundary
vorticity have created sporadic weak mid-level (850 MB) mesos with
this short sub-6km deep convection. Should continue to see a small
hail and gusty wind threat through the afternoon with these as they
move north though the landspout/weak tornado threat seems to be low
as cells struggle to remain discrete and rain into each others
updrafts. Clearing behind the main line may yield enough instability
to see a few more storms form behind this initial line but remain
weaker with more mid level dry air to contend with. Gusty synoptic
30+ mph winds will begin to drop off after sunset as we develop the
evening inversion leaving a pleasant night.
A breakdown of the upper low over the next 2 days will see continued
cloud cover with periodic shower chances through Wednesday as the
low meanders south with weak upper flow to move it along.
Another 0.10 to 0.25" remains possible before this round of rain
ends primarily north of HWY 200. A drier period begins after
this round moves out with eastern ridging forming atop a
developing cutoff low in desert SW arching into the northern
plains by late week. Northerly flow along the eastern edge of
this ridging will see shortwaves rounding the ridging with our
next potential rain maker Friday though not looking at a soaker
with this quick moving clipper type system. Low level ridging
will see relative humidity dropping below 40% each day Thursday-
Sunday for at least a portion of the forecast area. The
strongest surface pressure gradient doesnt move over head until
Friday/Saturday quelling concerns of fire weather though remains
something to monitor.
Chances for precip look to then stem from ridge riding waves late
weekend into early next week Though uncertainty remains high with
timing and amounts. Highs through the period as ridging dominates
will be in the 60s to 70s with average highs in the mid 60s for the
second week of May. Lows in the 40s to low 50s each night for the
week should provide near term relief from any late season frost
threat for gardeners who have already started spring planting or are
looking to start.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 629 PM CDT Tue May 7 2024
Line of showers and isolated thunderstorms continue to move
north. The line is currently stretching from northern Towner to
northern Beltrami county. Winds behind the showers have been on
the stronger side, with gusts up to 30kts at times for DVL, FAR,
GFK, and TVF. This will be periodic over the next three hours.
After, winds will turn toward the east and diminish. Rain
chances continue through 03z for BJI, DVL, TVF, and GFK.
Otherwise, clouds will remain broken for all sites but FAR
through the overnight period. DVL and BJI will reach MVFR
ceilings around midnight and remain there through 12z. Further
chances for isolated showers near the end of the TAF period,
with MVFR BKN ceilings.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Godon
DISCUSSION...TT
AVIATION...Spender
Area Forecast Discussion
National Weather Service Indianapolis IN
917 PM EDT Tue May 7 2024
.KEY MESSAGES...
- Severe storms expected today, especially during the afternoon
and evening. All forms of severe hazards are possible.
- Additional severe storms are possible Wednesday afternoon and
evening. All forms of severe hazards are again possible.
- Heavy rain is possible at times through Wednesday night. Localized
flooding will also be possible.
- Periodic chances for showers and a few storms late week into early
next week.
- Normal to slightly below normal temperatures from Thursday
into early next week.
&&
.MESOSCALE UPDATE...
Issued at 917 PM EDT Tue May 7 2024
A general east-west axis of mixed mode convection continues mid this
evening S and SE of Indy, with a tendency for some new cells to
develop along the southern outflow boundary of the existing complex.
Besides continued strong/severe weather potential into late evening,
heavy rain amounts and rates have materialized due to some training
cells, with radar rainfall estimates of 1.5 to 2.5 inches in some
areas. As a result, a flood advisory is in effect til midnight EDT
for parts of Johnson, Shelby, Rush, and northern Decatur counties.
Use caution and watch for significant ponding of water on roads and
low-lying areas and near creeks and streams.
Eventually CAMS take the current activity ESE and out of central IN,
while a new potential focus may occur over parts of southern IN into
KY. Overnight, storms should end across our region as drier and more
stable air temporarily infiltrates central IN. Then renewed
destabilization and additional convection should occur Wednesday
afternoon and evening in our area, especially southern half.
Issued at 753 EDT Tue May 7 2024
Convective mode has become a little messier over last hour or two,
with a mix of supercells and now a more linear segment across Shelby
and Johnson counties. The line segment evolved due to outflow
mergers creating a local cold pool which has pushed east across
Shelby, increasing the potential for some strong/severe wind gusts.
Meanwhile, the back portion of this line over Johnson has evolved
more into a heavy rain/local flood threat as cells train east across
the county. However, a new line segment now over southern Johnson is
moving more normal to its own axis, increasing the local wind and
hail threat in that part of the county.
Several supercells are still in play over central IN, one warned in
Rush County, others in Randolph that appear to be weakening last
couple radar scans. Additional cells expected this evening along and
south of current activity as unstable SW inflow continues to impinge
on convective outflow boundary from ongoing cells. Besides
continuing severe threat, additional heavy rain could result in more
ponding of water and localized flooding.
Issued at 634 EDT Tue May 7 2024
Scattered supercells continue to track E and NE over central IN. The
earlier cell that was approaching southern Indy metro failed to
pulse up as cell mergers occurred more in front flank of cell which
may have limited unstable inflow into updraft zone. Nevertheless it
remains a core entity as it passes across SE Marion Co. at this time
and will continue to monitor as it moves east.
Other supercells not showing much low-level rotation at this time.
This could be due to slightly more veered boundary-layer flow into
the storms, limiting some streamwise vorticity ingestion into
updraft zone. Nevertheless, we are getting some good hail cores with
occasional 1 inch reports still happening with strongest cells.
Most concern over next 1-2 hours would be the storms along/near the
I-70 corridor which have unimpeded axis to unstable low-level inflow
and reside on the northern gradient of the maximum instability over
far SW IN on southward. Storms also are riding along their own
created outflow boundary which could possibly promote better
convergence and tilting/rotation into the updraft. Will continue to
monitor.
Issued at 540 PM EDT Tue May 7 2024
Persistent supercell continues to track east across southern and
eastern Putnam Co. at this time. Storm has history of 1 inch
diameter hail, with isolated report up to ping pong in Putnam along
with funnel cloud as relayed by EMA. Still healthy rotation aloft
but less so in low-levels. Still not seeing really any cell or
shower mergers into southern inflow flank of storm yet although
radar now showing some cells developing just to its south and moving
NE toward it. Such mergers can enhance low-level streamwise
vorticity and rotation potential, subsequently leading to better
tornado potential (but not always). WoFS data suggests that some
mergers and some cell strengthening may occur as it continues to
propagate east toward southern half of Indy metro over next hour,
although rain from downwind part of storm will affect Indy area
shortly. Will continue to monitor trends on this storm closely.
Elsewhere, we are continue to monitor supercell structures over
Boone, Clinton, and Tipton counties at this time.
More updates to come.
&&
.SHORT TERM (This evening through Wednesday)...
Issued at 259 PM EDT Tue May 7 2024
Our focus in the short term is the severe weather potential this
afternoon.
THIS AFTERNOON
Synoptic Overview
A potent trough and associated jet streak are beginning to edge into
Indiana. We`ll find ourselves in the right exit region of the jet
streak. Typically, the right exit region isn`t usually considered
the best place for large-scale lift. However, we`re dealing with a
cyclonically curved jet streak which maintain favorable lift in both
the right and left exit regions. The best vorticity advection looks
like it will pass to our north. Still, enough divergence exists
within the jet streak for synoptic-scale lifting this afternoon.
500mb height falls signify that this large-scale lifting is ongoing.
At the surface, a cold front across northwestern Illinois will
advance eastward. This feature will provide another source of lift
in addition to the dynamics above. A potent low-level jet (35-45kt
at 850mb) will advect warm buoyant air back northward eroding what
remains of a cold pool/CIN. Rapid destabilization of the planetary
boundary layer (PBL) is expected as we head into the afternoon
through a combination of advection and solar insolation. Additional
lift will arise from the buoyant forces near the surface. As such,
thunderstorms are likely once again both along the boundary and
within the open warm sector.
Convective Mode
Now that we`ve reasoned why thunderstorm development is once again
expected this afternoon, we can take a look at convective mode and
hazard types. Latest RAP analysis shows plenty of low-level shear,
and this is corroborated by latest satellite imagery showing
billows/waves in the warm sector stratus (17z). RAP soundings depict
0-1km shear over 20kt, with effective bulk shear over 50kt.
Hodographs are long, with some curvature in the lowest 3km
(especially as one heads further east). The thermal profile shows
modest lapse rates with tall CAPE profiles and abundant low-level
moisture. NAM/GFS soundings are quite similar. The jet streak aloft
is generally perpendicular to the warm sector and cold front.
Therefore, multicell clusters and supercells appear to be the most
likely storm mode today. Reason being is we have a lot of shear with
the best large-scale lift is passing to our north. Additionally,
faster flow may still be a bit further west and storms could have
poor anvil-level relative outflow (which may promote multicell over
supercell). The jet streak will be deeper into the region later in
the day as well, so supercell mode may become more prominent after
6pm or so. Linear mode may be possible in the evening as the
front/pressure trough becomes a bit more parallel with the shear
vector.
Hazard Type and Timing
In terms of hazard type, we have an "all of the above" situation
this afternoon. Abundant buoyancy and shear in the lowest 1km should
promote tornado potential, with the possibility of a strong tornado.
Additionally, tall CAPE profiles with fast flow through the Hail
Growth Zone upward will promote a large to very large hail threat.
Dry mid-level air may lead to DCAPE values over 1000J/kg allowing
for efficient downward momentum transfer and a damaging wind threat.
These hazards are most likely within supercells that develop. In
terms of timing, given the lack of a cap in the model soundings...it
seems probable that convection fires up rather early in the
afternoon. As of 17z, low- level stratus still has a wavy
appearance signifying low-level stability...though this is
beginning to change. Satellite trends show convective rolls and a
few towers beginning to develop over northern Illinois. The most
probable timing of convective redevelopment is between 18-21z.
TONIGHT
High-res guidance generally shows convective activity exiting the
area before 06z. As mentioned above, some linear convective mode is
possible in the evening...and if the line orients itself parallel to
the shear vector then storm training may occur. This may promote a
heavy rainfall threat. This seems most probable in the south and
eastern portions of our CWA. Surface winds diminish quickly after
sunset and another round of overnight fog is possible as PBL
inversion develops.
Wednesday`s severe weather threat will be covered in the Long Range
Discussion below.
&&
.LONG TERM (Wednesday night through Tuesday)...
Issued at 259 PM EDT Tue May 7 2024
WEDNESDAY/WEDNESDAY NIGHT...
BOTTOM LINE UP FRONT - Another day of potentially significant severe
weather is likely Wednesday, with all hazards possible, though the
corridor of highest severe potential may be further to our
south/southwest as opposed to today.
Central Indiana will begin the day on the cool side of the effective
warm front, which will likely lay somewhere along a Kansas City -
Paducah line and points east/southeastward by daybreak, though the
eastward extent becomes a bit more uncertain as this portion of the
boundary may be convectively reinforced.
All models, including CAMs, show this boundary pushing steadily back
northward through the day on Wednesday, though there is decent
variability in how quickly this occurs and what that means for
destabilization and evolution of tomorrow`s rounds of convection.
The rough consensus appears to be that the front will get as far
north as the I-70 corridor or thereabout by late afternoon, though
convection will very likely be in progress by this time, as minimal
inhibition is expected within the warm sector. Convection may then
push eastward and perhaps even east/southeastward as potential
upscale growth occurs, cold pools become established and storms
begin to ride the instability gradient along the boundary, which may
be held up on its northward lift by this activity, which is a
failure mode for severe episodes we`ve seen in this area several
times before. The lack of capping may also contribute to a variety
of convective modes, with discrete storms ahead of any possible QLCS
segments, though all hazards look to be on the table - with relative
threat of each hazard depending significantly upon these modes.
Shear will not be an issue, as deep layer and low level bulk shear
numbers are more than adequate for organized storms across the area,
especially along the boundary - and significant instability will be
present within the warm sector. It appears that convection will fire
fairly early in the day over western Missouri into NE Oklahoma/NW
Arkansas, initially moving eastward or even ENE-ward with the mean
flow, with a gradual shift to eastward motion and then ESE-ward with
time as convection organizes and begins to modify the environment.
Focus area over the last 24 hours has shifted south somewhat, and
given the CAM guidance and uncertainties with respect to warm
frontal progress/airmass recovery further northward into central
Indiana, this appears reasonable. If QLCS mode becomes predominant
early in the day, this activity may well skirt across the southern
portions of central Indiana in late afternoon/early evening as it
moves eastward and then begins to develop southeastward along the
instability gradient. However far north the warm front manages to
progress, any convection near and along it, particularly discrete
cells, will have the potential for tornadoes, possibly significant,
though again, the most likely corridor for this appears to be just
off to our south/southwest at this time.
Significant rainfall potential will exist with this activity, and a
hydrologic threat will require monitoring tomorrow into tomorrow
night, dependent upon storm track and evolution.
THURSDAY - TUESDAY...
BOTTOM LINE UP FRONT - Cooler with periodic shower/storm chances
through the rest of the forecast period.
Lingering shower and storm chances will accompany a secondary cold
front and the upper level trough axis as it passes through the
region on Thursday, and periodic shower chances will be necessary
throughout the remainder of the long term as individual waves within
the larger upper level cyclonic flow impinge upon the region.
Temperatures will be cooler, perhaps significantly so, late in the
week and into the weekend, though some recovery back into the mid to
perhaps upper 70s appears likely by early next week as the large
scale upper trough pulls northeastward and heights begin to build
locally/flow becomes quasizonal.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 732 PM EDT Tue May 7 2024
Impacts:
- Thunderstorms continue to impact KIND through 0-1z. KBMG could see
impacts through 2-3z.
- Patchy fog possible overnight.
Discussion:
Thunderstorms remain mainly east of a line from Kokomo to Terre
Haute. Strong and severe thunderstorms remain possible for the next
few hours with very poor flying conditions within or near any
shower/storm, which at this point should not impact KHUF or KLAF.
After storms exit the area, skies should clear and some patchy fog
may form overnight. Winds may go light and variable for a time.
Wednesday will feature increasing clouds and a renewed storm threat.
The best storm chances appear to be across southern Indiana, with
lesser chances north. Will leave out thunder mention for tomorrow
for now without good confidence on timing and location but include
some convective cu. Winds become southerly around 10-14 kts
Wednesday afternoon.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
MESOSCALE...Funk
SHORT TERM...Eckhoff
LONG TERM...Nield
AVIATION...CP
Area Forecast Discussion
National Weather Service Louisville KY
1022 PM EDT Tue May 7 2024
.KEY MESSAGES...
* Potential for multiple rounds of strong to severe storms
through early Thursday. All severe hazards will be possible.
There is some potential that a significant severe weather
event could develop Wednesday afternoon and night.
* Localized flooding potential will exist where repeated rounds of
heavy rainfall occur, especially Wednesday night into early
Thursday.
* Below normal temperatures return by Friday and persist into
the weekend.
&&
.UPDATE...
Issued at 1022 PM EDT Tue May 7 2024
Small storms developed in southern Indiana over the past couple of
hours and took full advantage of strong low level shear to manage to
produce at least one probable small tornado.
IR satellite showing anvils flowing rapidly downstream in strong
shear, keeping convection in southern Indiana shallow. Weak mid-
level lapse rates are preventing more robust updrafts. With such
strong shear in place, updrafts will need to be strong to maintain
themselves and support deep convection.
However, the cells earlier, which struggled even to produce much
lightning, managed to spin-up a possible tornado! Just goes to show
that large, powerful thunderstorms aren`t always necessary if low
level shear, LCLs, low level lapse rates, etc., support rotation
reaching the ground.
Convection upstream over the southern tip of Illinois and
southwesternmost Indiana continues to struggle. Recent HRRR run did
a decent job with the small cells over southern Indiana, and has
been consistent all evening with producing more convection
overnight. So, will not call the all-clear quite yet. Indeed, deeper
convection has been developing into southwesterly flow upstream of
the Indiana/Ohio MCS. Will need to keep an eye on this trend as we
head into the overnight.
Issued at 841 PM EDT Tue May 7 2024
Storms have begun to fire across southern Illinois and southwest
Indiana in a corridor of 1.4" precipitable water, 3500 J/kg MLCAPE,
and 850mb theta-e ridging ahead of a surface boundary roughly from
St Louis to Terre Haute to Dayton. Additional development will be
possible south and southwest of the MCS over central Indiana.
Though mid-level lapse rates are weak, there are several other
factors that support the idea of severe weather over the next
several hours. Storms are entering a region of 1200 J/kg DCAPE with
steep low level lapse rates and ACARS soundings showing dry mid-
level air, supporting wind gusts reaching the surface. 60kt of
effective deep layer shear will support storm organization where
updrafts are strong enough, and with WBZ heights around 9k`, hail
will be a possibility. A TBSS has already been observed with a storm
via KLVX radar.
The above factors plus sfc-500m STP > 6, 200 m2/s2 0-1km SRH, and
700-1000m LCLs support the possibility of tornadoes. SPC has issued
a Tornado Watch for all of southern Indiana and central Kentucky
until 3am EDT/2am CDT.
Residents musn`t let their guard down regarding flooding. CAMS and
training of storms over central Indiana this evening suggest stripes
of heavier rain in locations that receive multiple thunderstorms,
which can lead to localized flooding issues. Flooding can be
particularly dangerous at night.
The most likely areas for severe storms and flooding appear to be
southern Indiana and north central Kentucky.
Issued at 612 PM EDT Tue May 7 2024
Quiet weather persists at this hour with warm, dry air aloft over
the region and strong forcing remaining to our north. Over the next
couple of hours the best chances for storms will continue to be off
to our north, especially over central Indiana.
Boundary showing up in visible satellite data from east central
Illinois to southeast Missouri is expected by CAMs to support
additional thunderstorm development this evening. Forcing
mechanisms, however, are subtle, with the more obvious triggers of a
surface cold front well to our west from northern Illinois to
northeast Texas and the aforementioned 5H impulse weakening slightly
as it lifts northeast. There may be a slight increase in the low
level jet from around St Louis into the Ohio Valley as the sun sets
that could assist in convective development.
While confidence in storms is not as high as earlier, patience is
often a virtue in these set-ups. It is not yet time to let our guard
down. If storms do fire, all severe hazards will be possible,
including tornadoes in a strongly sheared environment.
Issued at 422 PM EDT Tue May 7 2024
Isolated showers have developed across central Kentucky over the
past couple of hours but have struggled with weak forcing and mid-
level capping/weak lapse rates. Much stronger storms have erupted to
our northwest over Illinois along a CAPE gradient and closer to a 5H
speed max advancing from Missouri into Illinois.
In central Kentucky and southern Indiana, warm, moist air is in
place with temperatures in the mid and upper 70s and dew points into
the lower 70s...resulting in increasing SBCAPE. CAMs suggest
additional storm development after about 5pm EDT, though remaining
widely scattered as the upper impulse over Illinois lifts to the
northeast towards the southern tip of Lake Michigan, remaining to
our northwest.
If storms do develop here this evening, they will be in an
environment of dramatically increasing 0-500m SRH/STP, especially
after 7pm EDT, and thus will have to be watched closely for signs of
rotation.
Going deeper into the evening, additional storm development to our
west will begin to move into the region for a continuing chance of
severe storms, especially over southern Indiana and central
Kentucky. The most likely timing for the most widespread convective
activity appears to be between 8pm and midnight EDT. A gradual
diminishing trend in intensity is expected after midnight, though
showers and thunderstorms will continue to push southeastward
through central and southern Kentucky.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 130 PM EDT Tue May 7 2024
Latest 500 MB analysis and water vapor imagery shows a strong upper
level low pressure system over the Dakotas with plenty of jet stream
energy and associated dynamics and moisture through the mid MS river
valley and into the Ohio River Valley. Dew point temperatures
across the region were in the upper 60s to lower 70s with a very
humid feel ahead of the cold front draped across the Mid MS river
valley. Ongoing convection from the first round of showers and
thunderstorms was pushing into the I-75 corridor. The environment
outside of ongoing convection is uncapped based on mesoanalysis
data, which increases concern for points west of I-65 where shear is
steadily increasing.
====================================================
The next round of Thunderstorms
Timeframe: 20z (4pm EDT) - 09z (5am EDT)
Confidence on severe potential: Medium
====================================================
The next potential round of strong to severe storms will come ahead
of a cold front to our west. Storms could start firing off by mid
afternoon and push eastward into the western CWA border starting
around 20-21z. HREF guidance progs an axis of ~70 degree dewpoints
to nudge in from the southwest ahead of the front, and with low
level lapse rates at their steepest levels due to peak heating, HREF
MUCAPE generally range from 2,000-3,000 J/KG. Strong deep layer
shear of 45-55kts will be co-located with this higher instability
axis, which will support organized convection that includes
supercells. Should severe storms develop, all severe hazards would
be possible.
Additional re-development along the front overnight as it slides
into the region remains possible. Confidence is low on the severe
potential with this activity, though, as the earlier afternoon and
evening storms could leave cold pools or stabilize the atmosphere in
their wake. Assuming the storms have access to an untapped or
`recovered` warm sector, all severe hazards would be possible with
severe activity.
It`s important to note that the severe weather environmental
parameters we`ll observe into the overnight hours are very unusual
for this region and something we typically see only a handful of
times per year. If we get severe supercellular storms, some will be
capable of producing very large hail in excess of 2 inches. Modest
low level shear and helicity in this moderately unstable environment
could result in a strong (+EF2) tornado as well.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 130 PM EDT Tue May 7 2024
==== Significant Severe Weather Outbreak Possible Wednesday
afternoon-Wednesday Night ====
==== Local Flooding Possible Wednesday Night ====
Moderate to high confidence remains for a significant regional
severe weather event Wednesday afternoon into Wednesday night for
parts of the Ohio and Tennessee Valleys.
Synopsis: Closed upper low centered over the northern Plains
Wednesday morning will gradually work eastward towards the Upper
Mississippi Valley during the day as a weak shortwave ridge builds
over the Ohio Valley. At the surface, a quasi-stationary boundary
will be located just along the Ohio River as an elongated area of
sfc low pressure over the central plains slowly works towards
central IN by Thursday morning. As the sfc low works towards the
Ohio Valley, the stalled boundary will become a warm front with dew
points south of the boundary over southern IN and central KY in the
mid/upper 60s to even a few areas to the south near 70. As
temperatures warm into the low/mid 80s during the afternoon, the
atmosphere will quickly destabilize with SCAPE values ranging
between 1500-3000 J/kg. HREF ensemble soundings indicate 0-6km bulk
shear > 50 kt.
The main challenge will be timing and placement of initial
convection during the day Wednesday. While the setup for a
significant severe weather threat continues over the Ohio Valley as
indicated by the SPC enhanced outlook (3/5) over our entire county
warning area, there are a few elements that could potentially impact
the overall severe threat during the day Wednesday.
Hi-res models are in agreement of remnant boundaries associated with
Tuesday nights storms to be located across central TN Wednesday
morning. This boundary looks to be the focal point for convection
initiation during the day Wednesday. Timing and location of
convective activity Wednesday morning into the early afternoon could
play a large role in just how strong storms get later in the
afternoon and evening over central KY and southern IN. Some of the
hi-res convective allowing models want to develop convection over
far western KY while others start to develop activity over MO
Wednesday morning. Any cloud cover and potential outflow from this
activity arriving early in the day before maximum heating would
likely limit storm severity towards the afternoon. Another limiting
factor with early convection to our south and southwest early
Wednesday would be to limit the LLJ which is indicated by the 00z
HRRR and to some extent the NAM3K. Finally, placement of the stalled
boundary and its northern progression allowing for the CWA to be in
the deep warm moist sector behind increasing instability over the
area. A lot of the above mentioned factors will be determined by how
the storms Tuesday into Tuesday night unfold over the area. With all
that being said, all threats are still possible Wednesday afternoon
with initial cellular development before becoming more of a QLCS
ahead of an approaching cold front Wednesday night into Thursday
morning.
Tornado threat: Model sounding continue to indicate low-level
curvature on hodographs showing the potential for plenty of
streamwise vorticity ingestion by storms, with some eSTP values for
tornadoes >=EF2 Wednesday afternoon.
Hail threat: With forecast soundings showing large CAPE in the -10
to -30C hail growth zone. Strong deep layer shear and steep mid
level lapse rates keep large hail a possibility.
Wind threat: While we may not have a strong LLJ to work with, high
PWAT values leading to precipitation loading along with steep low-
level lapse rates increase the threat of strong damaging wind gusts.
Flash Flood threat: With PWAT values above 1.50" and numerous
clusters of storms Wednesday afternoon along with a line of storms
Wednesday night into Thursday moving through the area. Add to that
already wet ground from rains over the last couple of days will
increase the threat and concerned for localized flash flooding.
Especially in areas south of the Kentucky parkways that will see
heavy rain on Tuesday then again on Wednesday.
With the above mentioned limiting factors, confidence is higher for
linear severe storms associated with the approaching cold front than
the development of supercells during the afternoon and early evening
on Wednesday.
**Like any forecast, there are sources for potential bust. Any
convection that might get going Wednesday morning could decrease
instability for afternoon redevelopment, as would cloudiness being
more widespread, or stronger capping in our position well within the
warm sector. While a significant severe weather event is still a
possibility, this isn`t a done deal. Stay tuned to the latest
forecast information between now and Wednesday afternoon to keep
abreast of changes.**
Thursday - Monday:
Amplified pattern develops Thursday through the remainder of the
forecast period with a large ridge building to the west and deep
trough across the eastern US. This will keep occasional
shower/storms chances in the forecast thanks to a series of
shortwave disturbances moving through the northwest flow aloft.
Temperatures during this period will be below normal for early May
with highs in the 70s and even 60s on Friday.
&&
.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 735 PM EDT Tue May 7 2024
A complex large-scale storm system will affect the airports
throughout this TAF period. As for local TSRA, the first wave is
expected to pass through the region from northwest to southeast
tonight ahead of an upper impulse over Illinois and a weak low level
jet over the Ohio Valley. The most likely timing for strong or
severe storms will be mid through late evening, with a weakening
trend expected after midnight.
The next main chance for storms will come with atmospheric
destabilization tomorrow afternoon, and even moreso tomorrow evening
as a cold front comes in from the west. Some of the storms may once
again be strong or severe, with heavy downpours likely.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...13
SHORT TERM...DM/MCK
LONG TERM...BTN
AVIATION...13
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1032 PM CDT Tue May 7 2024
.KEY MESSAGES...
- Isolated to widely scattered thunderstorms will dot parts of
east-central and southeast Missouri and southwest Illinois into
the early evening. A few of these storms could be strong to
severe with large hail the dominant threat.
- Scattered to numerous severe thunderstorms are expected on
Wednesday, primarily from late morning through the afternoon
into early evening. The overall set-up is quite volatile
supportive of large hail, damaging winds, and a few strong
tornadoes.
&&
.SHORT TERM... (Through Late Wednesday Night)
Issued at 236 PM CDT Tue May 7 2024
Surface features are rather nebulous this afternoon with largely
veered southwesterly surface winds across the area and very weak
convergence within the flow across southwest IL into southeast MO.
The air mass in this area is currently quite unstable with SBCAPE
of 3000+ J/KG and deep layer shear on the order of 70 kts. If we
can get some sustained deep storms, which is more challenging
with the weak convergence/forcing, then supercells would be the
favored mode. Given the veered low-level flow, the hodographs are
rather straight favoring large hail as the main threat. The
convergence zone is expected to shift east of the area by early
evening with an ill-defined cold front settling southeastward
across the area as well and the cumulative boundary becoming
stationary across southern MO and southern IL later tonight. After
the current storms, things look rather tranquil tonight with
potential for some patchy fog.
Wednesday continues to be a day of big severe weather potential but
there is uncertainty on how it will all play out. The overall set-up
hasn`t changed much with a surface low moving through west-central
MO in the morning, and lifting through northeast MO and into west-
central IL by evening. Accompanying the movement of the low, the
aforementioned boundary to the south will move northward as a warm
front with a trailing cold front accompanying the surface low.
Undiluted, the warm sector will become rather expansive and very
unstable by afternoon with potential for MLCAPE of 2500-3000+ J/KG.
There is also very little CIN forecast within the warm sector due to
heating, thus convection could evolve not only along the boundaries
but seemingly throughout the open warm sector. The possibility of
morning storms however leads to uncertainty in how convective
evolution will occur. At least a few of the CAMS including the 12Z
HRRR develop robust convection across western MO rather early in the
day, growing upscale into a severe QLCS and racing this eastward
across the southern half of MO and southern IL during the morning
and early afternoon. The best I can tell this early development
seems to be in response to a weak vort max in the southwesterly
flow and convergence well ahead of the cold front/surface low.
While I certainly can discount this scenario, it seems a more
plausible scenario is that convection will develop from late
morning into the early afternoon throughout central/southwest MO
and points east. Given the lack of cap, this might result in waves
of storms. The aforementioned strong instability and deep layer
shear of 60+ knots would favor supercells, however as mentioned in
the SPC SWODY2 outlook, the convective modes could be messy with
a mix of supercells and organized bowing segments. The
environmental set-up is quite volatile with the aforementioned
CAPE/SHEAR space, low LCL heights, steep mid-level lapse rates and
anticipated convective modes favoring all severe weather hzards.
Forecast hodographs across eastern MO and southwest IL in the
afternoon depict impressive clockwise curvature in the lowest few
kilometers resulting in large low- level SRH, also supportive of
strong tornadoes. By early evening, all the activity should have
moved east of the CWA and into the Ohio Valley region.
Glass
&&
.LONG TERM... (Thursday through Next Tuesday)
Issued at 236 PM CDT Tue May 7 2024
An elongated positively-tilted longwave trof evolves from SE Canada
through the SW CONUS by early Thursday, anchored by upper lows in
the Great Basin and lower Great Lakes. The Great Lakes upper
low/trof continue to deepen across the eastern U.S. through Friday,
largely in response to upper ridging building from the Pacific into
the Pacific NW, while leaving a cut-off low in the vicinity of the
far southwestern U.S. While there are differences in details with
the eastern upper trof structure and depth amongst the deterministic
models/ensembles and LREF, there is a dominant signal for the
presence of a trof and persistence of NW flow aloft Friday
through the weekend.
This pattern supports near to below normal temperatures beginning
immediately post-frontal on Thursday and continuing through
Saturday as a series of shortwaves in the NW flow bring weak
reinforcing cold fronts through the area. Accompanying the
shortwaves could be periodic precipitation chances, especially on
Thursday, however there is no strong signal for high pops at any
point in time.
Heights aloft are on the rise by late Sunday as the eastern trof
progresses into the western Atlantic and by early next week the flow
aloft across the region is relatively weak by mid-May standards. In
response we should see temperatures moderate and return to above
normal. The aforementioned temperature trends are fairly well
depicted in the NBM temperature guidance and the IQR generally
ranges from 5-8 degrees in the Thursday-Tuesday time frame.
Glass
&&
.AVIATION... (For the 06z TAFs through 06z Wednesday Night)
Issued at 1027 PM CDT Tue May 7 2024
Mainly dry and VFR conditions are expected through mid morning on
Wednesday with the exception of some patchy fog in low lying areas
including river valleys. Included a tempo group for fog at SUS and
CPS between 08-13Z. Then there will be an increasing chance for
showers and thunderstorms over Missouri and Illinois during the
late morning and afternoon hours. Have made minor adjustments to
the timing of showers and thunderstorms with 16-20Z at JEF/COU,
19-23Z at UIN, and 19-24Z at the St. Louis area terminals. Any of
the stronger storms tomorrow will be capable of producing MVFR,
possible IFR ceilings and visibilities, hail, and strong wind
gusts over 35 knots.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Memphis TN
913 PM CDT Tue May 7 2024
...New UPDATE...
.UPDATE...
Issued at 904 PM CDT Tue May 7 2024
CAMS have been over forecasting the development and coverage of
storms so far this evening. Just in the past 15 minutes of so we
have seen a bit of development near Memphis and Little Rock,
although the storm near Memphis dissipated almost as quickly as it
developed. There is a weak cap on the 00z LZK sounding, but CIN
is zero confirmed by the convective development. The potential
exists for rapid development over the next few hours although the
most widespread coverage is still expected closer to sunrise.
&&
.SYNOPSIS...
Issued at 236 PM CDT Tue May 7 2024
Showers and thunderstorms will start out as isolated tonight and
continue to increase in coverage and intensity by Wednesday. While
there are severe weather chances today, there is highest
confidence and concern for severe weather development on Wednesday
night. Lingering showers and thunderstorms are possible on
Thursday before a pleasant weekend.
&&
.DISCUSSION...
(This evening through next Monday)
Issued at 236 PM CDT Tue May 7 2024
A few residual showers are depicted on KNQA as of 2 PM as a low
pressure system pulls away from the region. Elsewhere most of the
region will experience a brief lull in precipitation for the
afternoon. Later this evening, a warm front will begin its northern
ascent and may initiate convection. The 12z HRRR is very aggressive
with this development across West Tennessee. The other CAMs and
preceding HRRR runs are a bit less aggressive and have a quicker
storm motion. The other CAMs are also have the storm mode more
isolated and less organized so only Slight to Likely PoPs were
carried. Confidence is low in severe weather criteria being met due
to diurnal stabilization trends (storms may be elevated). Another
limiting factor is models are hinting at this front stalling just to
the northwest of the Mid-South resulting in a lack of forcing.
Confidence continues to increase for severe weather potential
tomorrow evening under a large Enhanced Risk for severe weather. A
strong trough will interact with a surface low under strong upper
level divergence to allow convection to commence. Despite this
primed atmosphere, the greatest height falls are slightly to the
north of the Mid-South. CIPS analogs have lesser probabilities
than this time tomorrow currently at 60-70% as opposed to
yesterday of 70-90%. These values are still indicative of
organized convection generally along and north of Interstate 40.
GFS soundings indicate MLCAPE values ~3000 J/kg, steep lapse
rates, 40- 50 kts of effective shear, and a slight curvature to
hodographs. Another concerning aspect is as trends continue to
paint this as a nocturnal event, this means intensification of the
LLJ. It is not likely that any morning showers and storms squash
initiation as there is plenty of time to destabilize. Now is the
time to prepare for damaging winds of 70+mph, quick spin up
tornadoes that could be strong, and significant hail of 2" or
greater.
The line of storms should clear the area by 7 AM Thursday. Another
upper level disturbance from the Gulf Region may bring some showers
and thunderstorms Thursday afternoon and evening, mainly along and
south of Interstate 40. Some thunderstorms may be strong to severe.
On the brighter side, the weekend looks beautiful with dry and
seasonable temperatures in the 70s.
DNM
&&
.AVIATION...
(00Z TAFS)
Issued at 650 PM CDT Tue May 7 2024
VFR conditions will remain across the airspace through around 09Z
when ceilings begin to lower to MVFR conditions. Catching the timing
of VCTS at MEM was a bit tricky tonight as CAMs are in decent
disagreement. VCSH/VCTS is possible at JBR around midnight tonight,
though confidence was not high enough to include in TAF. South/southwest
winds look to begin gusting up to 25 kts across all terminals
shortly after sunrise tomorrow as the pressure gradient tightens
ahead of a cold frontal movement tomorrow. Another, stronger line
of thunderstorms looks to approach and move across MEM beginning
at around 02Z tomorrow evening. A PROB30 for -TSRA was added to
account for this line at MEM.
AEH
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
PUBLIC FORECAST...JDS
AVIATION...AEH
Area Forecast Discussion
National Weather Service Marquette MI
811 PM EDT Tue May 7 2024
.KEY MESSAGES...
-Rain showers this afternoon and tonight to bring half an inch to an
inch of rainfall to the area. Thunder chances are low, but are most
likely (15-30%) along the MI/WI state line.
- Multiple passing low pressure systems will keep rain chances in
the forecast into early next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 242 PM EDT Tue May 7 2024
GOES-16 Day Cloud Phase imagery shows high cirrus over the eastern
UP and east half of Lake Superior while a cumulus deck moves over
the remainder of the region along with weakly convective shower
activity along the MI/WI state line. RAP analysis shows a 984
mb low pressure over the ND/SD state line that is vertically
stacked and not moving much over the past 3 hours. Rotating
around the upper low are shortwaves that are supporting a now-
occluded front which is pushing into the UP and causing the
shower activity. CAMs show this shower activity overspreading
the UP throughout the afternoon and evening. The QPF forecast
has gone up a bit with the most recent run of the HREF, with the
central UP now seeing slightly over 50% probabilities of an
inch of rainfall compared to around 2/3 of an inch at the same
probability the last couple of runs. Mean MUCAPE values are
still meager, peaking at only around 100 J/kg along the MI/WI
state line so the ~15% chance of thunderstorms remains the
prevailing forecast along with no severe weather expected. RHs
fell into the 20s and 30s ahead of the occluded front in the
central and eastern UP this afternoon along with wind gusts
around 25 mph, but with cirrus overrunning the region preventing
RHs from falling further, expected reductions in wind with
time, and the arrival of showers within the next 6 hours, fire
weather concerns are low.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 307 PM EDT Tue May 7 2024
Upper air pattern consists of a closed 500 mb low over South Dakota
12z Wed which moves into the upper Great Lakes 12z Thu. A shortwave
over northern Saskatchewan 12z Thu dives southeast into the upper
Great Lakes late Fri. Get a glancing blow from a shortwave to the
south on Thu, otherwise pcpn ends by Wed afternoon.
In the extended, the GFS and ECMWF show a 500 mb trough and closed
low in the desert sw, a deep trough in the ern U.S. 12z Sat. The
trough in the ern U.S. moves to the east 12z Sun with more shortwave
energy poised to come into the area with a shortwave over Manitoba.
This shortwave dives into the upper Great Lakes 12z Mon and into the
lower Great Lakes 12z Tue. Temperatures look to be warming to above
normal this forecast period with an active pattern of alberta
clipper type systems moving through. One on Saturday, one Sunday.
Looks unsettled for this forecast period with some fronts nearby,
but no real strong systems to bring widespread rain at this point.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 734 PM EDT Tue May 7 2024
After the initial band of showers moved through the terminals
late this afternoon there will be a break in shower activity
for at least the next couple hours with VFR conditions. Showers
will move back in later this evening with a disturbance lifting
north through Lower Mi. SAW will have the best chance to see
steady rain from these showers later this evening into the
overnight hours. Expect conditions to lower to MVFR and then IFR
overnight at SAW and IWD in showers as an upslope n-ne flow
develops on the backside of the associated sfc low moving
toward the Straits later tonight. CMX also has a good chance to
see a period showers and MVFR cigs with this second of wave of
precip late evening into the early overnight, but then expect
CMX to improve to VFR late tonight (08Z or after) and continuing
into Wednesday as a downslope ne flow develops there. Conditions
will be slower improve at IWD and SAW during the day on
Wednesday under the n-ne wind flow with improvement to MVFR by
late morning and then to VFR mid to late afternoon.
&&
.MARINE...
Issued at 307 PM EDT Tue May 7 2024
Easterly winds diminish to below 20 knots tonight before becoming
northeast and increasing to 30 knots on Wed into Wed night. North to
northeast winds drop below 20 knots on Thu and stay that way into
Sun.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Small Craft Advisory until 9 PM EDT this evening for
LSZ244>246.
Lake Michigan...
None.
&&
$$
SHORT TERM...GS
LONG TERM...07
AVIATION...Voss
MARINE...07
Area Forecast Discussion
National Weather Service Mount Holly NJ
946 PM EDT Tue May 7 2024
.SYNOPSIS...
An area of low pressure tracks by to our north late tonight and
early Wednesday morning. This will be followed by a stronger area of
low pressure moving across the region Thursday. This low will track
east of the area Friday with additional upper level disturbances
tracking through the area this weekend. A warmer, drier pattern
looks to return early next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 935 PM, the last of the showers have dissipated with the loss
of daytime heating. Mostly just some bands of mid to high level
cloudiness streaming across our area. Some stratus and/or fog was
along and off the Delaware Beaches at sunset, and some of this
should expand northward and inland some late tonight as moisture is
on the increase from the south and southwest. Slowed the PoP
increase some from west to east overnight, as most of the guidance
including the recent runs of the HRRR have the bulk of the
showers/thunder closer to daybreak. Adjusted the hourly temperature,
dew point, wind and sky grids to account for the latest observations
and trends.
Otherwise, low pressure pivots around the Great Lakes. As the
associated warm front reaches the area, showers will commence. The
heaviest and most widespread will be north of Philadelphia. A few
thunderstorms are possible late as some instability is forecast to
advect eastward late tonight in response to strengthening flow and
low-level warm air advection. Rainfall amounts up to a third of an
inch are anticipated. Overnight lows will be in the 50s to lower 60s.
For Wednesday, the showers (and maybe a thunderstorm) associated
with the warm front will be moving out in the morning. For most of
us, it will be the first part of the morning. Clouds will diminish
in the afternoon allowing temperatures to rise quite a bit.
Wednesday`s highs will be the warmest of the week, with temperatures
ranging from the upper 70s well north and west to the mid to upper
80s south away from the cooler waters. It will become breezy with
southwest to west winds gusting 20-25 mph.
There could be some isolated afternoon showers/storms developing,
however the forcing for ascent is weak and this should limit the
coverage. The model forecast soundings do show a well mixed boundary
layer developing in the afternoon (inverted-V signature), and this
could result in an isolated gusty thunderstorm.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
A fairly busy/active weather pattern persists across the area
through the short term period.
For Wednesday night, one low pressure system moves out to sea as it
passes east of New England with a new low starting to move into the
midwestern states. This will eventually push a warm front towards
the area by Thursday morning which could start to bring in some
showers/storms towards sunrise across eastern PA and Delmarva.
Thursday is shaping up to be more unsettled as this next area of low
pressure referenced above moves across the region bringing more
widespread showers and storms. That said, there is still a lot of
uncertainty on the track of this system which will have implications
both on the high temperatures and the severe weather threat. Model
consensus maintains a low tracking eastward near Delmarva which
would limit how far north the warm front gets. Deep layer shear will
be quite strong meaning anywhere near and south of the warm front
will have a heightened severe weather threat Thursday afternoon into
the evening but right now the most favored area looks to be over
Delmarva and southern NJ. The Storm Prediction Center has a Marginal
and Slight Risk for severe weather across this region. This could
change, however, if the system and its warm front tracks farther
north. Currently expect highs Thursday ranging from the upper
60s/low 70s north to the mid/upper 70s south but again, this is
contingent on the track of the low. With an overall slower trend
with the system, showers/storms could last through a good portion of
Thursday night although any severe weather threat should diminish
through the nighttime hours with the loss of daytime heating.
On Friday surface, our earlier low pressure will track east of the
region while an upper level trough axis lags behind and pushes
through the mid Atlantic. This will keep chances for showers in the
forecast, especially north (POPs ranging from around 40 percent
south to 70 percent north), under generally overcast skies. It will
also be cooler with highs mostly in the upper 50s to mid/upper
60s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
In the big picture, the weather pattern will remain on the unsettled
side through the weekend as a long wave upper level trough lingers
in the east. This should be followed by a drying trend into early
next week. Heading into Saturday, chances for showers diminish, as
the initial shortwave trough moves out and shortwave ridging builds
in briefly for a time. However by late day the next disturbance will
be approaching and this could bring some more showers back into the
region, especially over eastern PA. So we keep the mention of shower
chances in the forecast but POPs are generally only in the 20 to 30
percent range. Expect highs mainly in the 60s under a mix of sun and
clouds so certainly not a washout. A better chance for showers
arrives by Sunday as the next shortwave trough swings through (POPs
40 to 60 percent) and there will also be more in the way of cloud
cover.
Finally by early next week it should start to trend warmer and drier
as the upper trough moves out and the flow over the east becomes
more zonal.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas...
Tonight...VFR conditions lower to MVFR/IFR overnight as areas of low
clouds and patchy fog develop. Some showers expected after 06z.
Southerly winds 4-8 knots becoming light and variable to locally
calm. Low confidence in the timing and extent of the sub-VFR
conditions.
Wednesday...MVFR/IFR conditions in the morning as showers end, then
improving to VFR. An isolated shower or thunderstorm possible in the
afternoon. Southwest to west winds increasing to 10-15 knots with
gusts to around 20 knots. Low confidence on how fast conditions
improve in the morning.
Outlook...
Wednesday night through Sunday...Sub-VFR conditions favored at
night in fog/mist and stratus, while VFR conditions overall
during the day for most days. Chances for SHRA/TSRA throughout
the period with sub-VFR conditions. More widespread SHRA with
scattered TSRA Thursday afternoon and evening.
&&
.MARINE...
Tonight and Wednesday...Sub-SCA conditions. Some fog develops
tonight before dissipating Wednesday morning.
Outlook...
Overall, sub-SCA conditions through the period. Scattered showers
and thunderstorms will result in locally higher wind gusts and seas,
with biggest impacts coming on Thursday afternoon and evening.
&&
.TIDES/COASTAL FLOODING...
Tidal ranges increasing this week as the new moon arrives this
evening. Limited onshore flow means that there won`t be much in
the way of serious flooding concerns, but still widespread
minor tidal flooding is expected with the high tide this evening
for Atlantic coastal zones, the Delaware Bay, and the tidal Delaware
River. A Coastal Flood Advisory remains in effect for these areas.
Another round of minor coastal flooding is probable for these areas
with the high tide cycle Wednesday night.
Flooding is not expected for our Maryland zones along the
Chesapeake.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Coastal Flood Advisory from midnight tonight to 5 AM EDT
Wednesday for PAZ070-071-104-106.
NJ...Coastal Flood Advisory to 2 AM EDT Wednesday for NJZ016.
Coastal Flood Advisory to 1 AM EDT Wednesday for NJZ012>014-020>027.
Coastal Flood Advisory from midnight tonight to 5 AM EDT
Wednesday for NJZ017>019.
DE...Coastal Flood Advisory to 2 AM EDT Wednesday for DEZ001.
Coastal Flood Advisory to 1 AM EDT Wednesday for DEZ002>004.
MD...None.
MARINE...None.
&&
$$
SYNOPSIS...MJL
NEAR TERM...Gorse/Kruzdlo
SHORT TERM...Fitzsimmons/MJL
LONG TERM...Fitzsimmons/MJL
AVIATION...Gorse/Kruzdlo/MJL
MARINE...Kruzdlo/MJL
TIDES/COASTAL FLOODING...PHI
Area Forecast Discussion
National Weather Service Salt Lake City UT
340 PM MDT Tue May 7 2024
.SYNOPSIS...A slow moving upper level trough will gradually cut-
off from the mean flow across southern Utah through the week. A
gradual warming trend is expected...though diurnal showers and
thunderstorms will remain possible across the higher terrain and
adjacent valleys into the weekend, especially across central and
southern Utah.
&&
.SHORT TERM (Through 06Z Thursday)...Mountain snow showers and
valley rain showers continue across northern Utah this afternoon.
At times, very gusty winds have been reported with these showers,
likely associated with higher momentum mix down and a relatively
dry sub-cloud layer in the valleys. Afternoon upper air and
satellite analysis indicates a broad, longwave trough remains
across the central and western United State. The main forcing with
this trough is shifting into the High Plains...however the
backedge of the trough will gradually shift south and eventually
cut-off from the mean flow by early in the long term forecast
period.
Expect showers to gradually end near to after sunset with the
exception of a potential period of lake effect south and east of
the Great Salt Lake. CAMS are nearly universal in developing a
band of transitory precipitation, extending to near Parleys
initially, then gradually shift to the Cottonwoods and then
western Salt Lake County and eventually diminishing near to after
10-12Z. If the residence time in any one location were to last a
few hours and precipitation changes to snow, slushy accumulations
would be possible on area roads. The most likely location for this
to occur would be the western side of the Salt Lake Valley
between 08-12Z. This is something to monitor moving through the
overnight period.
Next up, the Freeze Warnings. Upgraded the watches to warnings for
all zones and added the western Canyonlands zone for a >80% chance
of freezing temperatures in these locations. Even in areas not
currently expected to reach freezing such as Weber, Davis and Salt
Lake Counties, patchy frost will be possible. Those who have
vulnerable plants should either cover or bring them indoors.
Finally, with modest cold air advection and 700mb flow impacting
the gap area in Washington County, expect wind gusts to 50 mph
near canyons including towns such as the aptly named Hurricane and
Toquerville. Added a winter weather advisory for this location as
well.
Wednesday will feature occasional snow showers across the northern
mountains, however, accumulations will be light. Do not
anticipate the need to extend the winter storm warning.
.LONG TERM (After 06Z Thursday)...Early Thursday a broad positive
tilt trough will extend into the region, with a lobe of the
trough gradually cutting off over Utah and slowly moving
southwestward thereafter. This feature will then more or less
churn somewhere in the UT/AZ/NV/CA border region into the weekend.
In comparison to yesterday, guidance now is leaning in favor of
this feature lingering a bit deeper into the weekend or even early
next week before ejecting eastward out of the region, though
uncertainty is still noted in how exactly the flow evolves.
One of the impacts of this system will be the potential for
downslope winds across prone areas in far northern Utah. By
Thursday morning, most guidance moves the center of the
trough/cutoff low far enough south to begin imparting easterly
flow across northern Utah, and around 85% of ensemble members
carry some sort of light cold air advection over the terrain (two
necessary ingredients). High resolution guidance is just starting
to come into view, and suggest downslope winds begin to pick up
after 3am or so and peak sometime near or just after sunrise.
Still early, but HRRR does show potential for gusts generally in
the 35-50 mph range, primarily in prone areas of eastern
Weber/Davis Counties. Thursday night into Friday morning the low
becomes more favorably positioned, and ~80% of ensemble members
(especially ECM Ens members) show an enhanced cold air advection
component over the terrain. As a result, still thinking early
Friday on into mid morning Friday or so show the greatest
potential for stronger downslope winds. Currently thinking around
~60% chance to see gusts in excess of 45 mph in those typical
downslope wind prone areas, and ~15% chance of gusts in excess of
60 mph. Will begin to get a better idea as high resolution
guidance comes into view. Depending on the exact position of the
low, it looks likely some sort of easterly gradient is maintained
Friday night into Saturday morning, but almost all guidance ceases
any notable cold advection. Higher uncertainty here, but initial
thinking is maybe a few gusts, but probably much more marginal
overall.
As the low shifts around overhead or in relatively close vicinity
to the forecast region, it will also limit stability and help
maintain at least something of an unsettled day to day pattern. In
general, expecting isolated to scattered showers (and maybe a
thunderstorm or two), largely diurnally driven in nature, and with
the highest coverage over the high terrain and adjacent valleys.
Given guidance trending towards the low lingering longer into the
weekend, if not early next week, this will likely be the day to
day pattern for much of the long term period.
Once the low splits off from the parent trough, initially very
cold H7 temperatures will begin to moderate day over day. This
will impart a warming trend over the forecast region, with
Thursday afternoon highs around 5-10 degrees below climatological
normal increasing to near normal by Saturday, and likely slightly
above normal by Sunday on into early next week.
&&
.AVIATION...KSLC...Scattered rain showers will continue through
roughly 01z, with gusty and erratic winds and lowered CIGs to 4000
ft AGL possible near these showers. There is also a 25% chance
for thunder over KSLC, as well as graupel. Gusty west-
northwesterly winds as high as 40kts will continue until roughly
01-02z. Overnight (~04-12z), a band of lake-effect showers is
possible, mainly to the west of KSLC. However, there is still a
30% chance that this band directly impacts the terminal, bringing
a transition to snow and low (15%) chance for IFR conditions.
.REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers will
continue mainly north of KDTA through roughly 03z. These showers
will be capable of producing gusty and erratic outflow winds and
MVFR-IFR conditions (especially at sites above ~6000ft ASL that
will receive snow). Lake-effect showers are possible over the
western Salt Lake Valley overnight, potentially impacting KU42.
Gusty northwesterly winds will likely decrease after sunset across
all but far southern UT (south of KMLF). A weak front pushing
through southern UT later this evening will produce a transition
to gusty northerly to northeasterly winds overnight. KSGU may
waver between gusty northeasterly winds and light westerly winds
overnight (40% chance of the lighter winds). There is also a 30%
chance that KENV could see gusts exceeding 25kts overnight.
&&
.FIRE WEATHER...While the mountain snow showers and valley rain
showers will gradually end tonight, the system responsible for
this precipitation is going to slowly shift southward and largely
remain across the region through the weekend. Sensible weather-
wise, this will mean a gradual warming trend as this area of cut-
off low pressure weakens, with showers and thunderstorms possible
along the higher terrain and adjacent valleys each afternoon and
evening into the weekend.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Freeze Warning from midnight tonight to noon MDT Wednesday for
UTZ102-103-106-121-130.
Winter Storm Warning until midnight MDT tonight for UTZ110>112.
Wind Advisory from 9 PM this evening to 8 AM MDT Wednesday for
UTZ123.
WY...None.
&&
$$
Kruse/Warthen/Cunningham
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity