Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/07/24
Area Forecast Discussion
National Weather Service La Crosse WI
1015 PM CDT Mon May 6 2024
.KEY MESSAGES...
- Showers and storms are expected tonight through Tuesday evening. A
few strong storms are possible Tuesday afternoon and evening with
small hail being the primary threat.
- Pattern stays active into early part of next week with periodic
shower/storm chances. Severe threat low.
- Warmest conditions tomorrow/Wed with coldest day Thu. Mostly
within 10 degrees of seasonable normals (plus or minus).
&&
.DISCUSSION...
Issued at 210 PM CDT Mon May 6 2024
OVERVIEW: a series of upper level shortwave troughs look to spin
across/near the upper Mississippi river valley through the week,
bringing periodic shots for rain and a few thunderstorms. Severe
risk looks low and mostly confined to Tue. Current model blend
suggest a 50-70% for more than 1" through Friday, the bulk of which
comes tonight.
TONIGHT INTO TUESDAY: Showers and storms, a few strong storms
possible Tuesday afternoon
The 06.18z CAMs continue to depict two rounds of showers and storms
that progress through the area through Tuesday afternoon/evening.
The first of which is associated with a upper-level low situated
across the Dakotas with a corresponding negatively tilted trough
pivoting around the eastern edge of the aforementioned low. This
first storm mode would feature a long QLCS that originated from
supercellular convection across the Central Plains that will
progress towards our region where it will become instability starved
during the overnight hours. As a result, the 06.18z CAMs generally
paint a decaying band of more stratiform precipitation after
midnight with some embedded sub-severe thunderstorms as model
soundings only have a around 200 J/kg of MUCAPE to work with.
As this first round of showers and storms exits the region during
the mid-morning hours, diurnal heating will allow for instability to
increase across the area with MUCAPE values to around 1000-2000 J/kg
in the 06.15z RAP. Where cloud cover is able to exit, diurnal
heating will be maximized which will allow for localized boundaries
to setup which could initiate additional convection as shown in many
of the recent CAMs. As a result, exact location of any convective
initiation during the afternoon remains unresolved at this time.
However, with the general lack of bulk shear in the 06.15z RAP
during the later afternoon, storms will likely have a pulse nature
with small hail being the primary threat as 06.15z RAP soundings
show fairly lower freezing level during the afternoon and evening on
Tuesday. Cannot rule out some near-severe (half inch to nickel
sized) hail in the strongest storms. DCAPE values generally remain
on the lower side with roughly 500 J/kg present, suggesting that
some gusty winds to 30-40 mph could be possible with some storms as
their cores collapse. With the loss of daytime heating overnight
Tuesday, storms will begin to push northeast with the mean wind and
quickly weaken.
WED NIGHT/THU: medium range guidance in solid agreement with hanging
a sfc trough northwest of its parent low near the Ohio River valley,
reaching into northern IA/IL. In the upper level flow, pieces of
energy of set to spin east from the plains and southward out of
Canada. All the forcing mingles together to produce an area of
showers from southern MN across IA and over southern WI/IL. Locally,
the model blend favors keeping the higher chances (60-70%)
along/south of I-90. Instability is weak and the deeper shear gets
shunted southeast. So a few storms possible, but main severe risk
should be farther south.
FRIDAY NIGHT/SAT: another shortwave trough is set to drop in from
Canada with low level warm air advection/sfc front leading it in. No
tap to southerly moisture but has ample saturation to produce areas
of showers. Meager instability could pop a thunderstorm or too, but
this shortwave is more about another round of rainfall. Showers
could linger through much of the day Sat (moreso Mississippi River
east) with cyclonic flow and the western edge of the shortwave not
yet exiting.
TEMPS: mild-ish temps for the next couple days, colder Thu
Southerly flow promises a couple more relatively warm days for the
region with highs expected to top out near, or above 70 degrees -
about 5 to 10 degrees above normal.
Shots of colder, Canadian air along with rainfall associated with
shortwave troughs promise bouts of cooler air for the end of the
work week. Thu is trending the "coldest" (model blend painting only
a 20-30% chance to climb out of the 50s), but still only 5 to 10
degrees off the early May normals. EPS and GEFS then favor building
shortwave upper level ridging toward the end of the weekend, with
more zonal flow to kick off the work week. Expect a bump upward in
temps - at or above normal (near to above 70 for most).
&&
.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1015 PM CDT Mon May 6 2024
An area of showers and weakening storms will develop from the
west after 07.06Z tonight, spreading into Wisconsin through
Tuesday morning. Timing since the last update has slowed by an
hour or so. Ceilings may vary from VFR to MVFR with
probabilities for MVFR between 30-60% as the rain moves through.
Some reductions in visibility are possible within heavier
rains/storms. Additional scattered showers/storms will remain
possible into Tuesday afternoon/evening, but confidence in how
showers/storms will evolve later in the day is lower, so have
not included any explicit mention. With less mixing into the
predawn hours tonight at KLSE, did mention LLWS at KLSE, with
winds trending S/SW on Tuesday.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor/Rieck
AVIATION...JM
Area Forecast Discussion
National Weather Service Columbia SC
836 PM EDT Mon May 6 2024
.SYNOPSIS...
Scattered showers and thunderstorms continue through the early
this week as multiple disturbances move across the region. A
lull in activity is anticipated for midweek, with increasing
chances of showers and storms towards the end of the week.
Expect generally above average temperatures through the latter
half of the week before transitioning to near or slightly below
average next weekend.
&&
.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
The mid-upper level trough responsible for driving some
scattered-widespread convection is shifting across the TN
Valley and we have generally stabilized across the Midlands and
CSRA behind these showers-storms for the time being. Based on
the current satellite obs and hi-res guidance however, abundant
moisture, still relatively steep lapse rates, and forcing from
the mid-upper level trough will continue drive showers-storms as
weak destabilization and conditional unstable profiles aloft;
the HRRR has been in consistent agreement run to run in
widespread shower-storm activity overnight between 06-12z,
mainly remaining in the Midlands and Upstate. Low level lapse
rates will become isothermal however and should generally
prevent surface based convection, therefore greatly reducing
severe threat. But forcing from the upper trough and potentially
strong cold pool development could help anchor a few storms to
the surface layer still. So PoPs remain fairly high overnight,
with some likely elevated thunderstorms but the severe threat
will lessen somewhat. Heavy rain and flooding looks to be the
primary threat, especially in areas that saw heavy earlier, as
PWAT`s remain high (around 1.5-1.75").
&&
.SHORT TERM /7 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Tuesday and Tuesday night: A shortwave trough is forecast to continue
progressing eastward and out of the forecast area in the morning
hours. There could be a lingering shower or thunderstorm in the Pee
Dee early on in the day, but should be quick to exit the region if
there are any showers. Behind the shortwave, relatively flat ridging
moves over the region, allowing temperatures to rise to above
average for this time of year. A weak shortwave is forecast to move
through the broader ridge during the afternoon, mainly to the north
of the forecast area. With moisture expected to remain relatively
high through the day (PWATs around 1.5"), a few showers or
thunderstorms could develop, mainly for the northern portions of the
forecast area. Other areas should remain dry for the day. Overnight
lows should remain above average as well.
Wednesday and Wednesday night: Another warm day is expected on
Wednesday as the broad ridge remains over the region. However, a
larger scale upper trough is forecast to begin moving toward the
Southeast from the Upper Midwest. Another shortwave is forecast to
slide through the area in between the ridge and trough, which could
spark more showers and thunderstorms. A majority of the energy from
this shortwave looks to stay north of the area, but some guidance
extends the energy into our forecast area. Forecast soundings from
multiple models do support the potential for strong thunderstorms,
mainly north of I-20. The soundings near Columbia indicate a bit of
a warm nose around 700 mb, which should hinder convection. As you go
north toward the Charlotte area, this warm nose becomes less
pronounced, which is why PoPs are a little higher there and the
potential for stronger storms is greater there as well.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Thursday and Thursday night: The larger scale trough continues to
move eastward while a developing surface low and associated cold
front move towards the area on Thursday. Another shortwave is
forecast to move through the region, allowing for more convective
activity in the afternoon and evening hours. With the larger scale
trough approaching, temperatures aloft begin to cool, which would
lead to eroding that aforementioned warm nose around 700 mb. This
would lead to a higher chance for severe weather. Confidence has
increased a bit in this scenario as the various model guidance has
come into better agreement. That said there still remains some
timing and strength differences, which would affect the overall
severe weather potential for the region.
Friday through Monday: Another round of storms looks possible
Friday morning as some guidance indicates an MCS moving through the
Deep South will make its way into the Southeast during the morning
hours. There remains plenty of uncertainty with this scenario, so
confidence is on the lower side as of now (~20%). After that and a
cold front pass, more tranquil weather is forecast for the weekend
into early next week.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
High confidence in VFR conditions through the evening hours then
possible restrictions in early morning convection and stratus
around 12z.
Afternoon convection has generally shifted away from the
terminals and do not expect any issues this evening with
convection. Some lingering mid level clouds through 02z-03z then
some clearing expected overnight. Abundant low level moisture
remains in place and some radiational cooling likely will result
in some vsby restrictions at fog prone AGS, less confident other
terminals. Hi-res guidance suggesting a line of convection
moving southeastward through the Midlands along and north of
I-26 during the 09z-14z time frame so included a tempo group for
TSRA and cig/vsby restrictions. Otherwise, expect VFR conditions
with light southerly winds overnight picking up from the
southwest by 15z to around 8 to 10 knots with some afternoon
gusts approaching 20 knots.
EXTENDED AVIATION OUTLOOK...Morning fog/stratus less likely on
Wednesday with drier air over the region. The extended will be
active, with mainly diurnal convection each day.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1031 PM EDT Mon May 6 2024
.SYNOPSIS...
A summerlike weather pattern remains through mid week with mainly
afternoon and early evening showers and thunderstorms. Temperatures
will be well above normal Tuesday through Thursday. Showers and
thunderstorms will be more numerous ahead of a strong cold front
which will cross our region Thursday night and Friday. Expect drier
and cooler weather for the weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 1030 PM EDT Monday: Scattered showers and thunderstorms
continue across the SC Upstate and far northern NC Piedmont this
evening. There is also a line of storms pushing across the TN valley
as of the writing of this AFD. This activity has prompted a several
severe warnings and SPS` this evening, mainly for hail near quarter
size, which stands to reason given the icy cores but not-so-
impressive DCAPE values across the area. With 500-1,000 J/kg of
MUCAPE and 20-30 kts of 0-3 km shear remaining in place across the
forecast area this evening, strong to severe storm threat will
continue through at least the next few hours as activity progresses
eastward.Heavy rainfall and frequent lightning will accompany any
storms that develop. Did increase PoPs along the NC/TN border, the
central SC Upstate, and the northern tier of the CWA to likely to
categorical over the next few hours to account for thunderstorm
activity.
Otherwise...as flow turns NW aloft this evening, CAM guidance
continues to depict additional waves of scatter showers and
thunderstorms through tonight...which should fizzle as instability
wanes. The latest couple runs of the HRRR now bring a semi-organized
line of cells across the mountains, with some redevelopment over the
western SC Upstate after midnight. If that happens...instability
will be minimal but nonzero, and shear will remain elevated...such
that a stray strong to severe storm couldn`t be ruled out. Low
temps early tomorrow will be roughly 10 degrees above climatology
again.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 215 PM EDT Monday: A flat upper ridge will be in place across
the area Wednesday with weak short waves rippling through the flow
and across the area. A stronger short wave crosses the area early
Thursday as an upper low moves into the Great Lakes. At the surface,
a weak east/west oriented front stalls over the area Wednesday, with
a cold front moving in from the west on Thursday. The air mass
becomes very unstable Wednesday with moderate shear and mid level
dry air leading to increased DCAPE and sfc delta Theta-E values.
Coverage will be higher across the mountains, but severe storms will
be possible at any location across the area given these parameters.
Moisture increases on Thursday with less mid level dry air, DCAPE,
and sfc delta Theta-E values. Instability also falls, but could
remain in the moderate range while shear increases, approaching
strong territory. Convective coverage still favors the mountains,
but at least likely PoP will be featured across the area. Severe
storms will again be possible, but overall chance is more uncertain.
Highs Wednesday will push 90 degrees outside of the mountains, and
mid to upper 80s in the valleys then fall a few degrees Thursday.
Lows will be well above normal as well.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 240 PM EDT Monday: The Great Lakes low opens into a trough
which moves into the area Friday. A series of short waves keeps the
general troughiness over the eastern CONUS through the end of the
period. With the trough moving in on Friday, cyclogenesis takes
place near the Carolina coast along the cold front that moves
through on Thursday. Guidance keeps going back and forth on the
location of the front and cyclogenesis, along with any lingering
moisture and resulting precip. Have continued the trend of chance
PoP for now given the uncertainty. A series of weak clipper-like low
pressure centers of frontal systems move near or over the area
through the rest of the period. This leads to isolated to possibly
low end scattered showers for the mountains each day with dry
conditions elsewhere. Temps fall to a few degrees below normal by
Saturday, then rise back to near normal through the end of the
period.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Convection is underway across the SC
Upstate and parts of the NC mountains. Most model guidance
doesn`t bring this activity to KCLT directly, although some
lingering showers could certainly make it in the next 1-2 hours.
Some guidance depicts a round of showers and embedded thunderstorms
arriving from the west around and after midnight, but should this
develop it would mainly affect KAVL and the Upstate terminals.
IFR VIS and CIG restrictions are expected again tonight, with
the worst VIS expected for the mountain sites and the worst CIGs
expected virtually everywhere. This should scatter out quickly
after daybreak Tuesday, followed by prevailing VFR through the
end of the period. Some additional convection is possible in the
afternoon, but mostly looks to stay confined to the NC zones...and
may not even escape the mountains.
Outlook: Moist profiles will combine with a weak/stalled front
thru the mid-week, resulting in a period of active, mainly diurnal
convec- tive weather each day. There is potential for restrictions
associated with widespread fog and/or low clouds each morning. A
cold front moves in later in the week with continued chances of
diurnal convection.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...AR/JPT/MPR
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...MPR
Area Forecast Discussion
National Weather Service Houston/Galveston TX
623 PM CDT Mon May 6 2024
...New AVIATION...
.SHORT TERM...
(This evening through Tuesday Night)
Issued at 246 PM CDT Mon May 6 2024
High humidity, gusty southeast winds, temperatures in the 80s,
and widespread low/mid level cumulus rule the day on this Monday.
Capping has prevented the aforementioned cumulus from growing into
organized shower/thunderstorm activity. Capping will keep PoPs
low, but not necessarily non-zero. Isolated shower and thunderstorm
activity will be possible, especially across our northern counties.
Some runs of the HRRR today are showing thunderstorms nearing our
Brazos Valley counties this afternoon. That remains to be seen
but also cannot be ruled out due to weak disturbances embedded in
the flow aloft. Tonight promises to be another muggy night
featuring a developing low cloud deck and patchy fog.
At first glance, tomorrow looks very similar to today. However,
one key difference will be the increasing ~850MB WAA. 850MB temps
are expected to be 3 to 5 degrees celsius higher tomorrow afternoon.
Diurnal mixing should allow this WAA to mix down to the sfc layer,
resulting in hotter temperatures tomorrow afternoon. How hot?
Many inland locations are likely to make a run for the 90 degree
mark. Meanwhile, high levels of humidity will make it feel about
10 degrees hotter than the actual temperature. Some guidance,
particularly the NBM, is quite aggressive with afternoon dew
points, indicating widespread values in the 75F to 77F range. If
that were the case, then heat index values could be another 3 to 5
degrees hotter than currently predicted. But since the NBM is
featuring a higher dew point bias today (not uncommon), we opted
to mix in some "drier" guidance to tame those afternoon dew points
down to 73-74F (still nasty).
Even though tomorrow`s heat is technically below advisory criteria,
these temperatures and dew points are quite high for early May.
Therefore, practicing heat safety is warranted. Heat safety
precautions include drinking plenty of water, wearing light
clothing, taking frequent breaks in the shade or indoors if
working or doing physical activity outside. If you think it`s
uncomfortable outside, so does your pet! Never leave children or
pets in the car this time of year (LOOK before you LOCK).
Self
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 246 PM CDT Mon May 6 2024
You might be thinking "it`s too early for it to be this hot!" as you
see low 90s in the forecast through Thursday...so let`s take a brief
peek into the climatology (for the City of Houston). We have a high
temperature of 90F forecast for Houston on May 7th...the last time
our first 90+F day was this late was in 2018. Four out of the last
five years we`ve hit 90+F for the first time of the year in
March/April. Our average first day of 90+F temperatures is May 6th,
so we`re right around average...nut 90s are 90s so that`s hot no
matter what month it is. With southwesterly flow aloft persisting,
850mb temperatures will reach the 20-25C range Wednesday and
Thursday. This is around their 99th to MAX percentiles (NAEFS/GEFS),
so high temperatures in the low 90s are definitely supported. The
heat itself isn`t the only story...given the saturated soils from
the recent rainfall, humidity values will be a bit higher leading to
elevated heat index values (100-105F). Additional moisture moves in
on Thursday ahead of an approaching frontal boundary (we`ll get to
that soon), so this is the day we`re watching the closest for now
for a potential early season Heat Advisory since our bodies aren`t
acclimated to the heat just yet) in addition to lingering effects
from the previous rainfall in some areas (power outages & outdoor
clean-up efforts).
Now about that cold front! An upper level low will traverse from the
Northern Plains to the Great Lakes region midweek. The surface low
will follow a similar east-southeastward track through the Central
CONUS and drag a cold front towards Southeast TX. The cold front
will be sitting on our doorsteps as early as Tuesday morning, but
the parent low sits nearly stationary over the Northern Plains so
there won`t be much movement until the new surface low forms further
south midweek. We will be in the warm sector, so there`ll be plenty
of shear and instability to work with. Recall our elevated 850mb
temperatures though which is the source of our subsidence inversion
layer aloft (cap), so any storms that attempt to develop along and
ahead of the front will have to battle that. That cap is stronger
the further south you go on both Wednesday and Thursday. While there
is a slight risk of severe weather (level 2 out of 5) for portions
of Southeast Texas Wednesday/Thursday, it all depends on if any
convection can break the cap to tap into the elevated instability
and shear. Rain chances Thursday are mainly along and north of I-10
as the front pushes through the area and we`ll likely be too capped
further south for any storms to make it.
Temperatures do cool down a bit post-FROPA with highs on Friday and
over the weekend back into the 80s and overnight temperatures mainly
in the 60s. The surface high pressure that builds in on Friday
behind the front pushes eastward over the weekend allowing for
moisture to return. Rain chances remain over the weekend with
various shortwaves passing through, but most notably on Sunday as it
appears a coastal trough will drift through the area.
Batiste
&&
.AVIATION...
(00Z TAF Issuance)
Issued at 623 PM CDT Mon May 6 2024
Decreasing S to SE winds and the development of widespread MVFR ceilings
will return to the early this evening and persist through early tomorrow
morning. Areas of IFR ceilings along with patchy fog are possible too.
Winds will start out SW tomorrow then become S to SE tomorrow afternoon.
Expecting to see low end VFR ceilings tomorrow afternoon. Will start
to indicate lowering decks once again heading into the tomorrow evening
thru Wednesday morning time period.
42
&&
.MARINE...
Issued at 246 PM CDT Mon May 6 2024
Light to occasionally moderate onshore flow will continue through
midweek until a cold front pushes offshore late Thursday night. This
persistent onshore flow will keep seas in the 3 to 5 ft range and
may occasionally reach 6 ft in the farshore waters. Another
consequence of the moderate onshore flow is elevated rip current
risks. Dangerous rip currents can be expected along all Gulf facing
beaches through midweek. We`re also monitoring for the potential of
coastal flooding along Gulf-facing beaches around midweek during
times of high tide. A cold front pushes offshore on late Thursday
night bringing a period of northeasterly winds that prevail into the
weekend. Showers/storms are expected to make a return over the
weekend, especially Sunday, as the next system arrives.
Mariners should note that high flows from area rivers, creeks, and
streams will lead to above normal water levels and strong currents
in the bays and ICWW well into midweek and can make navigation
difficult.
Batiste
&&
.HYDROLOGY...
Issued at 246 PM CDT Mon May 6 2024
Although there are periodic chances for scattered showers/storms
this week, this is not expected to result in any additional
flooding. Rivers will remain swollen for days (possibly weeks).
Do NOT go around barricades and stay out of the floodwaters.
Do NOT return to homes until officials deem that it is safe.
Minor to major river flooding continues for parts of Southeast
Texas, particularly along portions of the Trinity, San Jacinto, and
Navasota rivers. The following river points are either at or
forecast to go into Major flood stage as of Monday afternoon:
- Trinity River (Liberty): Major Flood Stage
- Trinity River (Goodrich): Major Flood Stage
- Trinity River (Moss Bluff): Major Flood Stage
- West Fork San Jacinto (Humble): Major Flood Stage
- Navasota River (Normangee): Moderate to Major Flood Stage
Remember to heed any instructions from your local officials and to
never travel through flooded areas or roadways. TURN AROUND, DON`T
DROWN. Please monitor updated forecasts via the NWS AHPS website
and/or the new NWS NWPS webpage (https://water.noaa.gov/) as the
river flood threat continues.
Also of note is that the downstream runoff from the previous
rainfall will cause continued rises along the Brazos River through
the end of the week. The Brazos River at Sugar Land, Rosharon, and
West Columbia are forecast to rise into minor flood stage at the end
of the work week and through the weekend.
Batiste
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 74 90 73 91 / 0 0 0 10
Houston (IAH) 75 90 75 91 / 0 0 0 0
Galveston (GLS) 76 82 76 84 / 0 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until midnight CDT tonight for TXZ436>439.
GM...None.
&&
$$
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
812 PM CDT Mon May 6 2024
.KEY MESSAGES...
- A line of thunderstorms will push through central Illinois late
tonight into Tuesday morning...bringing gusty winds and
downpours, as well as a few tornadoes possible.
- Scattered severe thunderstorms may re-develop Tuesday afternoon
and evening.
- Confidence is growing concerning on a more significant and
widespread severe weather event across much of central and
southeast Illinois Wednesday afternoon/evening.
&&
.UPDATE...
Issued at 810 PM CDT Mon May 6 2024
Line of severe storms is moving across NE/KS this evening and
approaching KS/IA this hour. Latest CAMs suggest this line will
reach the lower Illinois River Valley by around 09/10Z or 400/500 AM
CDT isolated storms popping up ahead of the main line around
08Z/0300 CDT. Given the unfavorable diurnal timing, storms should be
in a weakening trend, but couldn`t rule out some strong/severe
storms reaching as far east as central Illinois. Latest RAP suggests
pockets of 1000 J/kg MLCAPE will still be in place as the line
arrives with deep layer shear of around 30kt which would support
a continuing severe threat.
Deubelbeiss
&&
.DISCUSSION...
Issued at 258 PM CDT Mon May 6 2024
While a few showers persist in southeast/east-central IL this
afternoon associated with a shortwave moving ENE up the Ohio Valley,
this activity should gradually diminish this evening as a line of
thunderstorms organizes in the central Plains late this afternoon
and evening and sweep eastward toward central IL. Latest high-res
models are fairly unanimous with this line arriving in far west-
central IL around 2 AM a few hours past peak intensity. MUCAPE
values are forecast to be as high as 2000 J/kg as this line moves
into western MO/IA, down to 1000-1500 entering IL, and 750-1250 as
it exits IL to the east around 9 AM. This instability is also
increasingly likely to be elevated in nature as a stable layer
develops near the surface. Nevertheless, there will be a chance
for scattered severe wind gusts, especially west of the Illinois
River where SPC has denoted a Slight Risk of severe thunderstorms,
likely weakening to more isolated wind gusts as it weakens toward
the I-57 corridor. A few tornadoes could also spin up along the
line, again more likely toward western IL. There will likely be a
lull in precipitation behind this line during the morning hours,
but instability should return fairly quickly during the daytime
hours, as mean surface-based CAPE forecasts increase to 1000-3000
J/Kg (highest southeast of I-70, lower northwest of IL River).
Outflow boundaries left behind from the early morning thunderstorm
line could provide the convergence needed to start storms during
the afternoon. Strong deep-layer shear of 50+ kt should support
another round of severe thunderstorm development, containing large
hail, locally damaging wind gusts, and a few potential tornadoes.
SPC continues a Slight Risk of severe storms from around
Shelbyville to Champaign eastward, and a Marginal Risk for the
remainder of central IL counties. Predominant high-res model
guidance depicts these storms shifting southeastward out of the
area by mid evening.
The closed upper low over the Northern Plains will linger into
Wednesday, with another embedded shortwave likely inducing another
convective system Wednesday. Current model continues to track this
feature into central IL, perhaps a bit earlier with arrival in
central IL Wednesday afternoon. 1500+ J/kg and 50+ kts deep layer
shear continue to be forecast with this feature. SPC has depicted
an Enhanced Risk for severe thunderstorm from near I-72
southward, and a Slight Risk for much of the remaining area to the
north.
Following Wednesday`s system, a wavy northwesterly flow aloft sets
up for late week into the weekend, with the large scale trough axis
shifting east of IL. Although occasional precipitation chances can
be expected, amounts would be lighter, instability would be weaker
for a decrease in thunderstorm activity.
Temperatures will remain warm through Wednesday, with highs around
80 Tuesday, and Wednesday, then a strong downtrend can be expected
following Wednesday`s cold front, with highs dipping back down to
the 60s north of I-70 Thursday, and mid to upper 60s expected
both Friday and Saturday. Lows into the 40s are forecast for much
of the area each night Thursday night through Saturday night.
Temperatures will begin to trend back upward Sunday into early
next week.
37
&&
.AVIATION... (For the 00z TAFs through 00z Tuesday Evening)
Issued at 646 PM CDT Mon May 6 2024
A line of thunderstorms currently stretching from Nebraska to
Oklahoma will continue to move east overnight, crossing the
central Illinois terminals late tonight. Storms should be in a
decaying phase, but may still be strong producing gusty winds. A
period of MVFR ceilings and briefly IFR ceilings will accompany
the precip tonight. A warm front will lift north across the region
Tuesday morning with SE winds ahead turning SSW behind. A few
spotty showers and storms are possible during the day Tuesday, but
low coverage precludes any mention in the forecast at this time.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Indianapolis IN
1147 PM EDT Mon May 6 2024
.KEY MESSAGES...
- Isolated showers continuing this evening
- Severe storms expected Tuesday 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.
&&
.FORECAST UPDATE...
Issued at 945 PM EDT Mon May 6 2024
A boundary stretching from northwest to southeast across central
Indiana has been moving slowly north this evening. Near the
boundary, isolated showers continue to develop and then diminish.
With loss of heating, expect even these isolated showers to
gradually diminish over the next few hours. Kept some isolated
showers near this boundary for a bit.
Dewpoints were much lower across the far northern forecast area,
with lower 50s noted at Kokomo. Much of the remainder of the
forecast area has lower to middle 60s dewpoints. Current low
temperature forecast reflect this, with lows in the 50s north and
60s south, so made no significant changes.
With some partial clearing and light winds occurring in the
southeast, and rain having fallen there this afternoon and early
evening, added some patchy fog overnight. Will have to watch in case
fog becomes locally dense in places.
Left slight chance PoPs in the far west very late tonight with the
expected approaching line of convection. 00Z HRRR is slower though,
so may have to adjust timing with later updates.
&&
.SHORT TERM (This Evening through Tuesday)...
Issued at 305 PM EDT Mon May 6 2024
Convection has become more scattered this afternoon while the
thicker clouds this morning have mixed out a bit and enabled some
sunshine to filter through. This has introduced a weakly unstable
environment over much of the area as low pressure passes by to the
south. 18Z temperatures were in the 70s.
While some time will be spent on the scattered convective potential
into the early evening...the primary focus for the short term will
be on the initial severe weather risk focused on Tuesday afternoon
and evening as a series of waves aloft kick out from a deep upper
level low that will position itself over the northern Plains on
Tuesday.
Rest of This Afternoon and Tonight
Weak surface wave near the Ohio River passing by just south of the
forecast area this afternoon. Despite the lull in precip coverage
referenced above over the last few hours...starting to note an
uptick in convection across southern counties currently...likely
being aided by the weak instability. Broader area of rainfall just
northeast of KSDF may pivot into the far southeast counties over the
next few hours before kicking out to the east of the region.
Will continue to see isolated to scattered convection into the early
evening as the low shifts into northeast Kentucky. The presence of
near 1000 j/kg CAPE values should be enough for a few rumbles of
thunder as well. Showers will diminish shortly after sunset with the
loss of heating and a stabilizing atmosphere. Have held onto low
pops through mid to late evening but then expect dry conditions
thereafter.
The rest of the overnight will see low clouds gradually increase
with a focus turning to the west as the elongated robust convective
line slated to develop over the central Plains later this afternoon
steadily approaches the region from the west overnight. A strong
50+kt low level jet will help drive that convective line all night
with the likelihood that the storms will be nearing the Wabash River
shortly after 12Z Tuesday in a weakening state.
Tuesday Convective Round #1
Convection will be in the process of outrunning the better low level
jet dynamics by daybreak and the jet will weaken even further during
the morning as the storm line arrives into western Indiana.
Depending on cold pool depth from the overnight storms...convection
is likely to be in a subsevere state by the time it arrives in
western counties Tuesday morning. While overall instability profiles
will be minimal across the forecast area in advance of the
storms...an axis of stronger storm relative helicity within the 0-
1km range to enable the convection to maintain some level of
intensity as it tracks across the forecast area through midday.
Storms are likely to have hail and gusty winds associated with them
but model soundings do hint at the remnant of a nocturnal inversion
which should mitigate some of the wind transport to the surface.
Even while the instability is weak as mentioned above...the CAPE
profile is skinny and throughout the depth of the column with
likely presence in the hail growth zone as well. To sum
up...storms Tuesday morning will disrupt outdoor activities with
brief heavy rainfall and lightning diminishing and at least some
potential for small hail and gusty winds. But overall...the severe
potential looks low through midday Tuesday.
Tuesday Convective Round #2
The remnants of the morning convective line will be moving away by
early afternoon...leaving behind the warm front which will surge
north into north central Indiana and potentially leftover outflow
boundaries from the morning activity. With strengthening southerly
flow and an approaching surface wave along an occluded
boundary...the airmass will quickly moisten and destabilize with a
rapid advection of theta-e into the region by mid afternoon. This
will set the stage for renewed convective development after 18Z over
Illinois and eventually migrating into central Indiana.
All signs are coming into form for severe weather from mid afternoon
into the evening. CAPE values will rise to above 2000 j/kg with BL
shear and 0-1 km SRH values remaining more than sufficient for
robust convection initiation and development through the second half
of the afternoon. Diffluent flow aloft on the lee side of the deep
upper low over the Dakotas and the passage of an upper level wave
through the region will further aid convective development and
expansion. Model soundings become quickly favorable for all forms of
severe weather with directional shear within the boundary layer
present along with large right-turning hodographs.
While all of the above is strongly supportive of severe convection
and supercell development as well...the eventual position of the
warm front will become the wild card and could serve as a focal
point for the best threat for severe and perhaps rotating storms
carrying a tornado risk as well. At this point...that appears most
likely to align across far northern portions of the forecast area
during the late afternoon. With the strongest SRH values setting up
just to the northeast of the region...expect the primary tornado
risk late day Tuesday will be across northeast counties. Other than
the tornado threat...large hail will be a big concern with an
abundance of instability and stronger winds aloft within the hail
growth zone. Stronger cores will also carry a damaging wind risk with
drier air aloft and a near dry adiabatic flow through the boundary
layer.
Have highlighted the severe risk through graphics and products
shared on our social media platforms. Storms will shift east of the
area by late evening Tuesday as the front pushes back south and weak
ridging reestablishes. This is a temporary break in the storms with
another round of severe weather slated for late Wednesday and
Wednesday evening as the frontal boundary surges back north. More on
this in the Long Term Discussion below.
Temps...expect lows into the upper 50s far north with 60s elsewhere
tonight. Low level thermals support highs in the upper 70s and low
80s for much of the area Tuesday with a noticed uptick in humidity
as well.
&&
.LONG TERM (Tuesday Night through Monday)...
Issued at 305 PM EDT Mon May 6 2024
Late Tuesday night through Wednesday night...
A break in convection is expected to start late Tuesday night, with
even weak ridging building into central Indiana from the subtropical
surface high pressure to our southeast. Despite clearing skies,
lighter southwesterly breezes will hold dewpoints in the upper
50s...resulting in low temperatures around 60F across the region.
Wednesday will bring another favorable set-up for convection and
perhaps widespread severe weather with a warm frontal type boundary
likely slowly advancing northward near our southern counties ahead
of a strengthening surface low slowly approaching over the Middle
Mississippi Valley. Much of the day Wednesday may be the quiet
before the storm as the narrow ridging between the two systems
continues to cross the CWA...albeit eventually self-destructive with
the bright skies bringing low 80s and light southerly winds holding
dewpoints in the 55-65F range. Resultant CAPE by 21Z should range
from 1000-3000 J/kg from north-south...including moderately strong 7-
8 deg/km lapse rates over most of the area. Widespread 40-55 kt 0-6
km shear will also support arriving/developing convection.
So far appears most likely storm pattern will be a mesoscale
convective system initiating in the afternoon somewhere in the
central/eastern Illinois region...before tracking eastward into
Indiana during the late day/early evening hours. This would likely
transition into more of a heavy rain/flooding threat later in the
evening and into overnight hours, especially south of I-70 amid the
system`s warm sector`s anomalous precipitable water values
approaching 2.00 inches. While the environment would support
discrete cells ahead of a later MCS arrival...organized severe
weather`s location would be dependent on warm frontal position, with
timing likely determined by where/when storms begin to fire to our
west.
All severe hazards are on the table for PM hours Wednesday with
damaging winds and large hail the greatest threats during the
afternoon/evening...and flooding the greatest concern for the
evening/overnight. Although it is only early May, the set-up and
potential are perhaps more indicative of a June pattern with the
synoptic set-up able to effortlessly fuel ample deep moisture into
central and especially southern Indiana. Rain chances will drop
from west to east late Wednesday night as the supporting surface low
crosses the state. Total 24-hour rainfall potential for Wed-Wed
night will be 1.00-2.50 inches along/south of the I-70 corridor,
with less than 1.00 inch expected for most locations north of I-70.
Temperatures will be above normal amid the S/SW flow and overall
warm sector of the passing/approaching systems. Expect low 80s
ahead of convection Wednesday...while lows Wednesday night amid
decreasing chances of rain ranging from the upper 50s near Lafayette
to the mid 60s south of the I-70 corridor.
Thursday through Monday...
The last five days of the long term will then trend to at least a
couple northern stream, positively-tilted short waves cycling from
the northern Plains into the Midwest. Not the greatest certainty
with this pattern, with some guidance members originally hinting at
the second wave plunging and inducing a strong baroclinic
circulation near the Ohio Valley around the Sunday/Monday timeframe
...however, latest data now suggests amplification will be more
modest, which should keep the pattern more progressive over the
region thru the end of the long term.
This should translate to near to slightly below temperatures amid
west-northwesterly breezes. Thursday will be marked by robust to
gusty breezes as the gradient from the combination of departing low
pressure and the passage mid-level supporting vort. The 5-day
period will include several chances for at least stray showers under
the troughy flow...with more organized showers expected both
Thursday and Saturday per corresponding short waves. Widespread
and/or heavy rainfall could be possible early next week should the
weekend wave plunge and phase, although currently low chances in
this set-up coming to fruition. The normal max/min at Indianapolis
through the long term is 72/52.
&&
.AVIATION (06Z TAF Issuance)...
Issued at 1147 PM EDT Mon May 6 2024
Impacts:
- Line of convection will reach the terminals after 11z-13z
with MVFR ceilings and visibilities and briefly worse
flying conditions possible
- Good confidence more PM thunderstorms will develop and
move across
- SE winds less than 10 knots will pick up and switch to the
S and SW after 11z-13z. Gusts to 20 plus knots by this
afternoon and possibly briefly with the morning gust front.
- Gusts to 50+ knots and large hail possible in severe storms this
afternoon and evening
- Brief MVFR and worse fog can not be ruled out overnight and
until the line of thunderstorms gets close
Discussion:
A line of dying thunderstorms will move quickly ENE across central
Indiana this morning. MVFR and possibly briefly IFR conditions are
possible along with gusty winds.
The atmosphere will reload this afternoon and and upper trough and
approaching cold front along with increasing instability and
moisture will result in rapid thunderstorm re-development this
afternoon. Strong and severe thunderstorms are possible with this
activity this afternoon.
Winds will become gusty and switch to the S and SW during the day
with gusts to 20+ knots away from convection up to 50+ knots in
severe storms.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...50
SHORT TERM...Ryan
LONG TERM...AGM
AVIATION...MK
Area Forecast Discussion
National Weather Service North Platte NE
655 PM CDT Mon May 6 2024
.KEY MESSAGES...
- Windy tonight, especially over northwestern Nebraska with westerly
wind gusts up to around 55 mph.
- Small threat for lingering showers/thunderstorms early this
evening in the far northeastern forecast area.
- Upper level low pressure will meander across the northern and
central plains through mid week. This will lead to slightly
cooler than normal temperatures and a threat for
precipitation, mainly over central and northern Nebraska.
&&
.SYNOPSIS...
Issued at 355 PM CDT Mon May 6 2024
H5 analysis this morning had an upper low over northern
Colorado/southern Wyoming. A trough extended south-southwest of this
feature into the Four Corners. Downstream of this feature, a
negative tilted ridge extended from central Wisconsin, northwest
into eastern Saskatchewan and central Manitoba. Downstream of this
feature, a decent shortwave trough was located over the Bootheel of
Missouri. The 2 PM CDT surface analysis has a low over far
southeastern Montana. A Pacific cold front extended south-southeast
of the low into the western Nebraska Panhandle and just east of the
Palmer Divide of Colorado. A warm front extended east southeast of
the low into central South Dakota and portions of north-central
Nebraska. A dryline was present from west of Valentine, south to
just east of North Platte, to east of Oakley Kansas, to the far
eastern Texas Panhandle. Skies were generally cloudy east of highway
83 with clear to partly cloudy skies west of this route.
Temperatures ranged from 61 degrees at Ainsworth to 78 degrees at
North Platte.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 355 PM CDT Mon May 6 2024
The upper level low will drift to the northeast tonight from
the Black Hills into far southwestern North Dakota. On the
southern periphery of the low, strong winds are noted around the
750mb level this evening. This area extends from northeastern
Wyoming into the southern Black Hills and northern Nebraska.
Winds at this level are in the 70 to 80 KT range this evening.
With some additional low level cold air advection noted
particularly tonight, feel a large portion of these wind
velocities could make it to the surface, particularly over
northern Sheridan, and to a lesser degree over western Cherry
County. After looking at the hi res models (RAP and HRRR for
surface wind gusts) decided to hoist a high wind warning for
Sheridan County for tonight. Feel this is the area where the
potential is greatest for 60+ MPH wind gusts particularly this
evening. Elsewhere, there is another tongue of higher mid level
winds over SW Nebraska this evening. However, low level cold air
advection is less pronounced and given the diurnal timing,
winds should stay below warning criteria further south. The
upper level low will stall along the ND/SD border tomorrow. A
weak disturbance will rotate around the southern periphery of
the low Tuesday. With surface heating and cold air aloft could
not rule out a stray shower over northern Nebraska and will
leave this in the forecast. I did take out a mention of showers
over the southern half of the forecast area where H500 temps are
warmer and lesser instability is anticipated.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 324 AM CDT Mon May 6 2024
The upper level low will meander south Wednesday into Thursday.
This will lead to an increased threat for shower development,
particularly during the late afternoon and early evening hours,
when peak diurnal instability is realized. Anticipate this
quickly ending each day by sundown with some clearing skies
expected. The latest NBM forecast has widespread likely pops
during the Wednesday and Thursday time periods and believe this
is way overdone given the synoptic setup and low overall QPF
forecast. Drier conditions will set in late in the week as the
upper level low retrogrades southwest of the forecast area. A
northern stream trough this weekend will finally pick up the
remnants of the low and force it south then east of the area.
Temperatures will moderate back into the 70s for the weekend and
early next week with mainly dry conditions expected.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 653 PM CDT Mon May 6 2024
VFR conditions are expected over the next 24 hours. There will
be a brief period of LLWS in the early morning hours of 45 kts.
Winds at the SFC will remain breezy tonight through tomorrow
with winds mainly out of the west with gust of 30 to 40kts,
strongest winds across the northern Sandhills.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 6 AM MDT Tuesday for NEZ004.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...Gomez
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
908 PM CDT Mon May 6 2024
.UPDATE...
Issued at 908 PM CDT Mon May 6 2024
Forecast for overnight still looks on track as a line of strong to
severe thunderstorms looks to moves east across the area. There
are currently several lines of severe thunderstorms over eastern
Kansas and Oklahoma that are still expected to congeal and move
east into the western Missouri shortly and into the CWA overnight.
Latest runs of the CAMS including the HRRR have been consistent
in bringing the line across the area most likely between 2 am and
7 am. The low level jet is expected to continue to increase which
will bring more moisture overnight and increase instability ahead
of the line. As mentioned previously, the LLJ will increase the
potential for damaging winds and brief tornadoes with any bowing
segments.
There is potential for redevelopment ahead of the front tomorrow,
but those chances remain low.
Britt
&&
.KEY MESSAGES...
- Late tonight into early Tuesday morning, there is a threat of
strong to severe thunderstorms with damaging winds and brief
tornadoes the main hazards.
- On Tuesday afternoon, there is a conditional threat of a few
strong to severe thunderstorms in southeastern, far eastern MO
and southwestern IL.
- On Wednesday, the greatest chance of severe thunderstorms
exists. Severe thunderstorms will be capable of all hazards
including very large hail and a few strong tornadoes.
&&
.SHORT TERM... (Through Late Tuesday Night)
Issued at 255 PM CDT Mon May 6 2024
The CWA is currently beneath an upper-level shortwave ridge
sandwiched between a departing trough over the Ohio Valley and a
deepening, occluding closed low over the Northern Plains. Quiet
conditions under the shelter of the shortwave ridge will come to an
end tonight as a series of shortwave troughs eject northeastward
from the base of the closed low within southwesterly flow, helping
to establish the much-advertised active weather pattern that will
linger across the region through Wednesday.
The first shortwave is now entering the Central Plains, assisting
the development of strong to severe thunderstorms this afternoon and
evening ahead of a cold front as increasingly warm, moist, and
unstable air is transported northward via low-level southerly flow
in the warm sector. CAMs unanimously depict the thunderstorms in the
Central Plains congealing an eastward-moving QLCS tracking quickly
through MO tonight. This QLCS is expected to reach central and
northeastern MO around 12 to 2 am TUE. By that time, instability
will be relatively lower than earlier to the west, but the general
consensus in short-term model guidance is that SBCAPE will still be
over 1000 to locally near 2000 J/kg accompanied by 35 to 45 kt of
deep-layer wind shear, supporting only a gradual weakening of the
QLCS. In addition, 30 to 40 kt of 0 to 3 km wind shear and 0 to 1 km
wind shear will be available. Therefore, a threat for damaging winds
and brief tornadoes will accompany the QLCS, especially any
northeastward surging bowing segments orthogonal to the 0 to 3 km
wind shear vector. As the QLCS continues eastward through the
remainder of the CWA very late tonight into Tuesday morning,
instability will decrease slightly with both time and eastward
extent due to increasing BL stability and decreasing moisture.
Exactly how much this instability decreases is uncertain and will
impact if the QLCS weakens more quickly and if the corresponding
damaging wind and brief tornado threat decreases more quickly. The
weakening QLCS will depart the CWA through 7 to 8 am TUE.
The depth and southward extent of the QLCS`s cold pool Tuesday
morning will have implications on how much recovery of instability
can occur by Tuesday afternoon ahead of an approaching Pacific cold
front. However, even the 10th percentile of SBCAPE in the latest
HREF reaches 1000 to 1500 J/kg in southeastern MO and southwestern
IL, increasing confidence in instability recovering. Large-scale
ascent will be rather nebulous during that time, but weak moisture
convergence along a Pacific cold front passing through southeastern
MO and southwestern IL, perhaps far eastern MO during early
afternoon is the main potential catalyst for thunderstorm
initiation. Although not all CAMs initiate thunderstorms before the
front departs the CWA. IF thunderstorms develop, a few could be
strong to severe with deep-layer wind shear projected to be 50 to 60
kt with a few supercells possibly merging into small bowing
segments. The main hazards with any severe thunderstorms will be
damaging winds, large hail, and possibly a tornado, with the threat
ending by late afternoon as the front clears the CWA. Low-level CAA
behind the Pacific cold front will be counteracted by strong
insolation and downsloping of flow off the Ozark Mountains, leading
to widespread high temperatures in the low to mid-80s F near and
south of I-70 and in the upper 70s F northeastern MO and west-
central IL.
Pfahler
&&
.LONG TERM... (Wednesday through Next Monday)
Issued at 255 PM CDT Mon May 6 2024
Nearly all indications in model and analog guidance point to
Wednesday being the summit of the active weather pattern. As another
upper-level shortwave trough preceding an eastward ejection of the
Northern Plains closed low occurs from the Central Plains to
Mississippi River Valley, Tuesday`s cold front will lift back
northward into the CWA as a warm front on Wednesday ahead of a weak
surface cyclone. Along and south of the front, a strongly unstable
warm sector is anticipated to exist with model guidance advertising
MLCAPE of 2000 to 4000 J/kg during the afternoon amidst 50 to 70 kt
of deep-layer wind shear. There are still differences in how far
north the warm front reaches by afternoon, which will serve as both
the northward delineation and possibly an enhanced corridor of
significant severe thunderstorms, being an area of enhanced low-
level wind shear and SRH. Latest model guidance has this front
anywhere from southeastern MO to south-central IL by the afternoon,
significantly diminishing confidence in its effective afternoon
position. These discrepancies aside, confidence continues to
increase in the instability-wind shear parameter space being
supportive of severe thunderstorms capable of all hazards, including
very large hail (2" or greater in diameter) and a few strong
tornadoes (EF2 or greater). The exact timing and evolution of
thunderstorms is not entirely clear, but a preliminary window of
severe thunderstorms is from midday through evening on Wednesday
when a cold front finally pushes to the east of the CWA.
Most attention in the forecast was obviously given to the next 3
days, but confidence is high in at least a quieter weather pattern
after Wednesday as a period of time-mean upper-level northwesterly
flow through the weekend. This flow pattern will provide cooler,
near to below average temperatures as periods of low-level CAA
follow multiple fronts passing through the region. Some
opportunities for showers and thunderstorms will accompany these
fronts as well; however, not all ensemble model guidance contain
rain through the period and have timing differences related to
frontal timing and associated upper-level trough timing and
amplitude disparities.
Pfahler
&&
.AVIATION... (For the 00z TAFs through 00z Tuesday Evening)
Issued at 607 PM CDT Mon May 6 2024
Generally dry and VFR conditions are expected until after 06Z when
a line of thunderstorms will move into the area from the west
affecting COU/JEF between 07-10Z, UIN between 08-11Z, and the St.
Louis terminals between 09-12Z. These thunderstorms will likely
produce MVFR, possible IFR ceilings and visibilites and strong
wind gusts (possibly between 30-50 knots). The storms will move
off to the east by 12Z, with just a low chance of redevelopment
during the day on Tuesday. MVFR ceilings will linger through 18Z,
but mainly dry and MVFR conditions are expected during the
afternoon.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
736 PM CDT Mon May 6 2024
.KEY MESSAGES...
- Showers and a few rumbles of thunder are expected tonight into
Tuesday morning with up to an inch of precip possible.
- A Marginal Risk for severe thunderstorms exists tomorrow
afternoon/evening for far eastern Minnesota and western
Wisconsin. The main threat is hail and gusty winds, but there
is a non-zero chance for a tornado.
- Continued chances for showers with cooler temperatures through
the end of the week.
&&
.UPDATE...
Issued at 706 PM CDT Mon May 6 2024
No major changes to the forecast for today through Tuesday.
Fine-tuned the timing of the rainfall for later this evening and
overnight. The main concern is for a few stronger wind gusts to
mix down to the surface, but the overall threat for severe
weather remains low. Looking ahead to tomorrow, 18Z forecast
soundings off the NAM/HRRR and 21Z RAP show an uncapped
environment with close to 1000 J/kg. HiRes models have many
showers/thunderstorms across the region during the afternoon,
and as the previous shift mentioned, a few of these could
produce hail and gusty winds. There is also a non-zero chance
for a tornado or two depending on the surface instability and
boundaries.
&&
.DISCUSSION...
Issued at 225 PM CDT Mon May 6 2024
Cloud cover has continued to increase through the day with strong
southerly flow ahead of the expansive synoptic scale system
that is bringing a variety of hazards to the central CONUS.
Temperatures around noon had already reached the upper 60s and
low 70s, but with cloud cover becoming thicker and more
prevalent, we`ll likely only see a few more degrees of heating
for today. Winds have gusted into the 35-40 MPH range across
western Minnesota where a Wind Advisory remains in effect. Wind
speeds of 25-30 MPH are more common further east, but a few
higher gusts remain possible. As far as this evening`s showers
and thunderstorms go, CAMs are in good agreement that any
activity will hold off until after 00z. A northwest to southeast
oriented line will push across the southern half of Minnesota
through the overnight hours with the threat for thunder staying
confined to far southwest Minnesota. The showers will move into
the Twin Cities area after 06z and finally into Wisconsin by
09z. QPF amounts remain fairly unchanged from the previous
forecast (widespread 0.25-0.50" with more localized totals of
0.5-1.0")with the bulk of the precip ending by mid morning with
the now occluded front stretching across Minnesota. The focus
then shifts to tomorrow afternoon and the potential for the
development of a few strong to severe storms across far eastern
Minnesota and western Wisconsin. The triple point associated
with the low that continue to spin over the Dakotas should
remain just to the south of our forecast area to start the day,
but is expected to lift northward into western Wisconsin by the
afternoon. This region has been highlighted by a Marginal Risk
in the SPC SWODY2. Models have 700-1200 J/kg of CAPE across far
southeastern Minnesota and western Wisconsin tomorrow afternoon,
which would be more than sufficient to get some storms as the
front continues to occlude/move east. The primary hazards will
be hail and gusty winds with any of the stronger storms that
develop. There`s still some uncertainty regarding the initiation
time and just how far east storms will develop, but generally
the timing looks to be during the late afternoon and evening
hours. Any severe threat will diminish after 02-03z as
instability wanes and the line of showers and storms exits to
the east.
Heading into Wednesday, there`s not much change from the previous
forecasts. The upper low meanders slowly over the Dakotas and into
Minnesota with a few embedded waves leading to some additional
precip chances through Thursday, mainly for the southern half of the
forecast area. Continued low PoPs exist through the end of the week
with a separate shortwave dropping down out of Canada Friday. QPF
totals will be around 0.5-0.75" throughout those three days with
locally higher amounts possible. Temperature wise, Thursday is still
on track to be the coolest day of the period with highs in the
low 60s before rebounding quickly to end the week near 70 once
again.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 706 PM CDT Mon May 6 2024
VFR conditions this evening will give way to MVFR/IFR as a line
of showers with a few embedded thunderstorms lifts up from the
southwest this evening and moves across the region affecting all
TAF sites. Winds will be southeast ahead of this line of
precipitation, but then become more southerly and eventually
southwest late Tuesday into Tuesday evening.
KMSP...
No significance changes from the previous TAF. The timing for
showers with a few embedded thunderstorms remains on track for
after 06Z tonight. The rain will move out Tuesday morning, but
expect scattered showers and thunderstorms to pop up again
Tuesday afternoon and evening.
/OUTLOOK FOR KMSP/
WED...Mainly VFR. Chance MVFR/-TSRA. Wind NE 10-15 kts.
THU...VFR. Wind NE 15-20G25-30 kts.
FRI...Mainly VFR. Chance PM MVFR/-TSRA. Wind W 10-15 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Wind Advisory until 11 PM CDT this evening for Brown-Chippewa-
Douglas-Kandiyohi-Lac Qui Parle-Martin-Pope-Redwood-
Renville-Stevens-Swift-Watonwan-Yellow Medicine.
WI...None.
&&
$$
UPDATE...JRB
DISCUSSION...Dye
AVIATION...JRB
Area Forecast Discussion
National Weather Service Nashville TN
839 PM CDT Mon May 6 2024
...New UPDATE...
.UPDATE...
Issued at 819 PM CDT Mon May 6 2024
Thunderstorm activity definitely over-performed today with
several severe storms producing large hail, damaging winds, and a
couple tornadoes. Isolated activity remains across the area late
this evening with the strongest storms located along the
Cumberland Plateau. While these storms may continue to produce
small hail and gusty winds, the severe threat is diminishing and
will continue to diminish as we lose daytime heating.
As for tomorrow`s severe weather threat, thinking hasn`t changed
much from the earlier discussion below. Next round of
thunderstorms is expected Tuesday afternoon where daytime heating
and plenty of instability will allow for pop-up storms. Latest
runs of the HRRR don`t show much convection in the afternoon and
what does develop looks to be poorly organized. But as a weak
frontal boundary moves into Middle TN tomorrow night, that should
provide more forcing for better organization. Thunderstorms
tomorrow afternoon and into the overnight hours will be capable of
producing hail and damaging winds.
&&
.SHORT TERM...
(This afternoon through Wednesday Night)
Issued at 1211 PM CDT Mon May 6 2024
Humid conditions in place across the area this morning. Temps are in
the 60s and lower 70s. The earlier shower and thunderstorm activity
moved out earlier. We did get some isolated wind damage in our
southwest. Also...isolated 2-4 inch rainfall amounts across
Humphreys and also the Van Buren and Cumberland county areas.
For today, plenty of instability in place. Dynamics are a bit weak
but we should see some isolated to scattered activity fire in the
afternoon. Will need to watch those aforementioned rainfall areas as
a flood advisory or two may be needed. Otherwise, a few strong
storms cannot be ruled out with some high winds and some hail
possible later this afternoon. The convection should calm down for
tonight but the humid and muggy conditions will continue.
On Tuesday, some storms will fire but mainly in the afternoon.
Organization looks rather weak and convection may hinge on outflows
and heating. The slight risk which is in place does appear to be
aligned with Tuesday night when a dissipating frontal boundary
pushes some forcing into our area. Given the humid airmass,
instabilities will remain in play into the overnight hours. The
severe threat will include wind and hail potential.
Wednesday appears to be the biggest severe threat. We are currently
outlooked with an enhanced risk across our northwest. It looks to be
a 2 wave event. The first and weaker wave, will occur Wednesday
afternoon. some weak pre frontal forcing may tap into an
increasingly unstable environment. Mid level Lapse rates and shear
levels will be on the increase. I`d say isolated to scattered severe
storms could impact the mid state as the storms move east
northeastward. Wave #2 appears to be the main event. Models continue
to trend toward later with each run. Though synoptics dont look
classically dramatic, the forcing/instability/shear phasing looks
about as good as it has all spring. Case in point, the omega fields
are well organized and phase with 1500 j/kg cape, -7 showalter
values, 850 mb wind speeds of 45kts, and ml laps rates of 7C to 8C
at 06Z. Damaging winds, large hail, a tornado or two, and heavy
rainfall will all be possible. Those rainfall amounts will average 1-
2 inches for Wednesday/Wednesday night.
For the near term temps, its looking steady state and rather muggy.
Lows in the 60s and highs in the 80s.
&&
.LONG TERM...
(Thursday through next Monday)
Issued at 1211 PM CDT Mon May 6 2024
In the extended forecast, the first of 2 fronts will move through
early Thursday. The second will move through Thursday night and
bring some cooler air. A series of northwesterly impulses will bring
off and on showers into the weekend but nothing noteworthy.
Temperatures will cool down behind the Thursday fropas and actually
dip below normal for the weekend. You can look for lows 45 to 55 and
highs generally in the 70s.
&&
.AVIATION...
(00Z TAFS)
Issued at 608 PM CDT Mon May 6 2024
Scattered thunderstorms will die down over the next 3 hour across
the area. IFR/LIFR can be expected in any thunderstorms due to
low vis, low cigs, and heavy rain. VFR conditions overnight. A
slight chance for showers tomorrow morning with lower cigs that
may fall to near MVFR. Scattered thunderstorms will be possible
once again tomorrow afternoon and evening. Winds under 5 knots
through the overnight picking up after 16z with gusts up to 22
knots possible.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 67 85 69 86 / 40 50 70 60
Clarksville 66 83 67 84 / 20 50 70 60
Crossville 61 80 64 80 / 70 60 80 70
Columbia 65 84 68 87 / 20 50 70 60
Cookeville 63 81 66 82 / 70 60 80 70
Jamestown 60 81 64 82 / 70 60 80 70
Lawrenceburg 66 84 69 85 / 20 50 70 60
Murfreesboro 64 85 68 87 / 40 50 70 60
Waverly 67 83 66 85 / 20 60 70 60
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Clements
SHORT TERM...21
LONG TERM....21
AVIATION.....Mueller
Area Forecast Discussion
National Weather Service Blacksburg VA
555 PM EDT Mon May 6 2024
.SYNOPSIS...
The weather pattern will remain unsettled for much of the
week with a daily threat of afternoon and evening
thunderstorms.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 545 PM EDT Monday...
Key Messages:
1. Scattered showers and thunderstorms through this evening.
Some may bring locally heavy rainfall.
2. Showers and thunderstorms again Tuesday afternoon and
evening, with potential to be severe.
Keeping close to latest HRRR which has better handle on meso
situation. Should be a lull in activity in the southwest through
early evening so have cancelled the flood watch. A few more
showers, possible storms expected toward 10pm-midnight but
thinking is flash flood threat is too isolated/spotty at best to
have a watch. Only a few locations received over 2 inches of
rain.
Previous discussion...
A mid level shortwave crosses the area late tonight, as a low
surface tracks along a boundary oriented roughly northeast to
southwest across the Ohio Valley. Showers and thunderstorms
are already developing in west along and west of the Blue Ridge
today. Expect coverage to increase through this afternoon and
evening, as the shortwave approaches and as instability over the
area increases with daytime heating. Precipitable water on this
morning`s sounding was 1.15 inches, which is above the 90th
percentile relative to climatology for today. Forecast soundings
for this evening show an increase in PWATs, anywhere from 1.25
inches to 1.55 inches, depending on the high res model. Thus,
there is strong potential for locally heavy rainfall with any
of the storms today, which could lead to flash flooding,
especially in urban and low lying areas. Coverage of storms will
decrease after sunset with the loss of solar heating, and any
lingering showers should dissipate by midnight.
Weak mid and upper level ridging builds into the area briefly
tomorrow, and the warm front lifts northward into the lower Great
Lakes. Another shortwave will move through the upper Midwest ahead
of a deep upper low over the northern Plains Tuesday, which will
trigger some showers and thunderstorms over the Mid Atlantic and
Ohio Valley again later in the day. While the ridging aloft
will help to suppress a widespread severe threat, less cloud
cover tomorrow will result in more instability, and deep layer
shear will be sufficient enough to support more organized
convection, with a marginal threat for damaging wind and severe
hail. The stronger storms look to be mainly west of the
mountains on Tuesday, closer to the better dynamics, and where
terrain can add an additional source of lift.
Temperatures will be in the mid to upper 70s in the west and
around 80 in the east. Tuesday will be a few degrees warmer.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 130 PM EDT Monday...
Key Messages:
- Increasing flash flood threat
- Periods of numerous showers and thunderstorms
Short range starts with south west flow between large upper low over
the Northern Plains and upper ridging over the western
Atlantic. Then by Thursday a long wave troughing digs over the
eastern United States. The upper trough axis moves the coast for
Sunday and Monday.
At the surface the main cold front will cross the area Thursday.
Temperatures remain above normal ahead of the front, especially
overnight. Precipitable water values remain just above two
standard deviations above normal ahead of the front through
Thursday as forecast by the North American Ensemble. Plus
multiple days of numerous thunderstorms will steadily saturate
the soil leading to a higher probability of flooding by
Thursday.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 130 PM EDT Sunday...
Key Messages:
- Temperatures cool off
- Daily threat of thunderstorms continues
Overall synoptic scale pattern during this time frame features broad
troughing in the eastern United States and lower 5000 MB heights. No
particular focus to aid in development of precipitation but region
remains cooler than earlier in the week, but warm enough for a daily
chance of afternoon and evening showers and thunderstorms. For now,
enough of a break from the deep moisture to the forecast for Monday
dry.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
As of 550 PM EDT Monday...
Showers/few storms may impact BLF/LWB/BCB in the 03z-06z time
frame but overall coverage tonight into Tuesday will be limited.
Fog and low stratus appears to become more of an issue
overnight. IFR to LIFR or lower is likely in places where it
rained and where any breaks in the cloud cover occur which could
be almost any site. Will lean toward MVFR/IFR east and lower in
the west.
Any fog will likely erode by 14z. Ceilings will be variable
through at least midday Tuesday, but improve to VFR for much of
the area by Tuesday afternoon.
Showers and thunderstorms are expected again Tuesday afternoon,
but coverage looks too limited to have in the tafs.
Forecast confidence is average.
Extended Aviation Outlook...
Unsettled weather is expected for much of the week. Daily
threat of SHRA/TSRA through Friday. This will bring periods of
MVFR/IFR ceilings and visibilities at times. Winds through
Wednesday will favor a SW direction and may be gusty at times.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AS/PM/WP
NEAR TERM...AS/WP
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...AS/PM
Area Forecast Discussion
National Weather Service Springfield MO
725 PM CDT Mon May 6 2024
.KEY MESSAGES...
- Severe thunderstorms are likely tonight with the highest risk
areas along and west of Highway 65. Primary hazard is damaging
wind gusts of 70 to 80 mph. Additional hazards include
frequent lightning, a few short- lived tornadoes and half
dollar sized hail. Severe storms will move into the area after
9pm and continue overnight.
- Localized flooding is also a concern tonight across southeast
Kansas and western Missouri where localized pockets of 1-2
inches of rain will occur.
- Additional strong to severe thunderstorms on Wednesday. Exact
hazards remains in question, but very large hail, damaging,
and a conditional tornado threat are all in play. SPC has a hatched
Enhanced Risk (3/5) for most of the area.
&&
.MESOSCALE...
Issued at 725 PM CDT Mon May 6 2024
Storms have developed across a front across central Kansas and
Oklahoma this evening. This activity will continue to move east
this evening into tonight as an upper level trough moves east
into the plains. The high res models continue to be in good
agreement that these storms developing into a line and move
into the far western portions of the area by 11pm then moving
east across the area through the overnight hours exiting the
area to the east by early Tuesday. Damaging winds of 60 to 80
mph winds remain the main threat with these line of storms
especially along and east of Highway 65. Low level shear will
also support a brief tornado risk within the line of storms with
any surges to the east/northeast. Locally heavy rainfall and
localized flooding will also be possible with the best potential
across far southern Missouri. A few of the stronger updrafts
will be capable of hail up to the size of half dollars.
Storms have developed across north central Kansas into Nebraska
early this evening with another area of storms across central
Oklahoma into south central Kansas. The activity across northern
Kansas and Nebraska are forming into line segments and should
continue to move off to the northeast. The storms across
central Oklahoma into south central Kansas are currently
supercells in nature, but a cold pool should develop with these
storms as they move east which should allow these storms to
form into a line.
Once the storms across Oklahoma and southern Kansas form into a
line they will move off the east/northeast at 30 to 40kts. An
unstable air mass will be in place across the area with 1500 to
2200 J/kg of MLCAPE in place west of Highway 65, with values of
1200 to 1700 J/kg to the east overnight. Damaging straight line
winds will occur with the line of segments with gusts up to
80mph possible with the bowing segments. The 00Z SGF sounding
is showing down draft CAPES over 1000 J/kg which is also
supports strong down drafts. Low level shear will also increase
tonight. 0-3KM shear vectors are currently at 26kt across the
area and should increase to around 40kt to the northeast across
of the line of storms. This will support a QLCS tornado risk
with the line of storms with surges in the line to the
northeast.
There are some indications that the the southern part of the
line of storms will become outflow dominate across southern
MO/northern Arkansas and the outflow become parallel with the
0-3km shear vectors and could lead to the potential for some
training of storms and a localized flooding risk tonight. Will
have to watch exactly where this will form.
The storms will push east to the I-49 corridor by 9 to 11 PM to
the Highway 65 corridor by 12 to 2 AM, then to Highway 63 by 2
to 4 AM and the main line of storms should push east of the area
by 6AM, though some linger storms could occur across south
central Missouri until closer to 8 AM. Again damaging straight
line winds will be the main risk across the entire area with
wind gusts up to 80 mph possible and a few short lived tornadoes
mainly along and west of Highway 65. Hail up to half dollars
and localized flash flooding will also be possible tonight.
&&
.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 100 PM CDT Mon May 6 2024
Current Conditions and Synoptic Pattern: Water vapor and upper
air analysis shows a strong upper level shortwave trough across
Wyoming and Colorado with a 120kt upper level jet across Arizona
and New Mexico. Surface low pressure continues to deepen across
South Dakota with a secondary low across Kansas. A warm front
was in the process of lifting north through the area at this
time. A dry line was located across western Kansas and western
Oklahoma with storms already initiating across northern Kansas.
12z KSGF sounding showed a stable airmass in place (north of the
warm front) however soundings south of the warm front measured a
moist and unstable airmass. Visible satellite showed breaks
in the clouds across the area which should allow the warm front
to continue lifting north. A few showers were occuring however
many areas were dry with temps in the upper 60s to lower 70s.
Dewpoints were also creeping up into the lower 60s.
This Afternoon through early evening (1pm-8pm): The warm front
will continue lifting north through the area and temps will
continue warming up into the 70s which will increase
instability. While a few showers and even a thunderstorm may
develop, upper level forcing will still be to the west therefore
many areas will remain dry. All eyes will be on developing
supercells in a High Risk severe environment across southern
Kansas and northern Oklahoma. These storms will begin to evolve
into a line with time.
Tonight (After 9pm): High res ensembles continue to be in good
agreement that a line of severe storms will approach far
southeast Kansas in that 9-10pm timeframe. RAP forecast
soundings across southeast Kansas and western Missouri indicate
around 1500j/kg of ML CAPE (potentially up to 2000j/kg) with
40kts of 0-6km shear (this will increase further with time). The
120kt 300mb jet will be nosing into the area tonight. Also of
note is that 1.4-1.5in PW values which indicates a very moist
airmass. All this leads to high confidence that storms will
remain severe as they approach the area. Given the expected
linear mode and high instability/shear combo, damaging winds of
60-80mph will be the most likely risk as highlighted in the SPC
Moderate/Enhanced risk areas. That being said, any bowing
segments to the east- northeast or northeast could cause brief
tornadoes. We believe that the threat for supercells and
significant tornadoes will remain just west of the area however
if storms were slower to morph into a line then this expectation
would change. Southeast Kansas will need to closely monitor
storm mode tonight. The hail threat looks lower with this
system given the linear mode however hail up to the size of half
dollars will be possible.
As the line moves further east (between I-49 and Highway 65),
the damaging wind threat (60-80mph winds) and brief tornado
threat will continue. Latest RAP sounding for Springfield
between 11pm-1am still shows 1000-1500j/kg of ML CAPE with 40kts
of shear. PW values are also in the 1.4-1.5in range which
supports heavy rainfall rates.
While it does look like storms will gradually weaken as they
move east of Highway 65, the instability/shear combo will
remain high enough to keep the damaging wind/brief tornado
threat going however perhaps not as high a threat as areas
further west. In general, the line of storms will likely be
clearing the area by 5-7am.
Overall a busy overnight period is expected with the increasing
potential for widespread damaging winds. We will continue to
heavily message safety information for this night time severe
event.
Contemplated a Flood Watch for areas west of Springfield tonight
however given the progressive nature of this line, flooding will
remain localized and brief. 12z HREF does show a few pockets of
1-2 inches of rainfall across far southeast Kansas therefore we
will be monitoring this risk.
Tuesday: The airmass will likely be worked over from overnight
storms and combined with mid level height rises we should see
low precip chances (less than 20 percent). Winds will turn
southwesterly during the day with skies clearing and temps
reaching the upper 70s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 100 PM CDT Mon May 6 2024
Wednesday: Another shortwave trough will move through the
southern Plains with a surface front moving through the area
during the afternoon or early evening. Strong instability will
be available with the NBM mean showing between 2000-2500j/kg of
surface based CAPE along and southeast of the I-44 corridor.
This instability and unidirectional shear could produce
supercell thunderstorms and the area is in a Enhanced Risk on
Wednesday. There still remains uncertainty with frontal timing
and since we are not in the window of time yet for the high res
guidance it is urged to stay up on the forecast for Wednesday.
Thursday into the Weekend: The overall trend during this time
period is drier conditions and cooler temps. This is likely due
to a pattern shift with northwest flow aloft causing north
surface winds. Friday looks to be the coolest day with highs in
the 60s in many locations.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 532 PM CDT Mon May 6 2024
Gusty southeasterly winds will continue this evening, some MVFR
ceilings could occur, but mainly VFR conditions will occur. A
few isolated showers and maybe a thunderstorms may be possible
this evening but most locations will remain dry through 9PM.
Storms have developed across central Oklahoma and Kansas early
this evening. These storms will continue to move east and
developing into a line or lines of storms. This activity will
move into the area western portions of the area late this
evening and through the rest of the area overnight. These storms
will have the potential for damaging winds, frequent lightning
and brief heavy rain. IFR to LIFR conditions will occur with the
storms. The storms will move east from west to east overnight
into early Tuesday morning. Winds will turn to more
southwesterly behind the storms and remain gusty on Tuesday.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...None.
MO...None.
&&
$$
MESOSCALE...
SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Wise