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Severe WX April 1-2 (overnight) Severe Weather Event

wx_guy said:
Hell, just do what most local mets have started doing and just go with a "1" to "5" scale. Easy and makes sense.
Click to expand...
Yep, I've seen a trend towards that and wouldn't be surprised if we eventually see a concerted effort on SPC's part to just turn it into a numbered system. Still love the verbal descriptors as a nerd, but people are probably going to handle numbers better.
 
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1233 PM CDT TUE APR 01 2025

VALID 021200Z - 031200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THE
MID-MISSISSIPPI VALLEY TO THE LOWER OHIO VALLEY...

..SUMMARY

NUMEROUS SEVERE STORMS ARE LIKELY WEDNESDAY AND WEDNESDAY NIGHT
ACROSS THE SOUTHERN GREAT LAKES, MID MISSISSIPPI VALLEY, AND NORTH
TEXAS INTO THE ARKLATEX. SEVERE WIND GUSTS, VERY LARGE HAIL, AND
STRONG TORNADOES ARE POSSIBLE.

..SYNOPSIS

A BROAD MID-LEVEL TROUGH AND POWERFUL 100+ KT JET STREAK WILL
ACCELERATE NORTHEASTWARD FROM THE CENTRAL PLAINS TO THE GREAT LAKES
ON WEDNESDAY. STRONG ASCENT FROM THE ADVANCING UPPER TROUGH AND
PRIMARY SHORTWAVE IMPULSE WILL SUPPORT A DEEP (~990MB) SURFACE LOW
MOVING FROM THE NORTHERN PLAINS INTO THE WESTERN GREAT LAKES. A WARM
FRONT WILL RAPIDLY MOVE NORTH THROUGH THE MORNING WHICH WILL ALLOW
FOR A BROAD WARM SECTOR FEATURING 60S F DEWPOINTS TO EXPAND AS FAR
NORTH AS EASTERN IOWA TO NORTH-CENTRAL OHIO/SOUTHERN MICHIGAN BY
WEDNESDAY AFTERNOON/EVENING. A COLD FRONT ATTENDANT TO THE DEEP
SURFACE CYCLONE WILL SWEEP EASTWARD, WITH WIDESPREAD STRONG TO
SEVERE STORMS EXPECTED TO BE ONGOING ALONG/AHEAD OF THE FRONT AT
DAYBREAK.

..MID MISSISSIPPI VALLEY TO THE LOWER OHIO VALLEY

THUNDERSTORMS WILL LIKELY BE ONGOING FROM NORTHEAST TEXAS TO THE
UPPER MIDWEST AT THE BEGINNING OF THE PERIOD. EAST OF THIS ACTIVITY,
A WARM FRONT WILL SURGE RAPIDLY NORTH ACROSS ILLINOIS AND INDIANA
WITH MID 60S DEWPOINTS EXPECTED ACROSS THE MID-MISSISSIPPI VALLEY TO
THE LOWER OHIO VALLEY BY MID-DAY. AS TEMPERATURES WARM INTO THE
UPPER 70S TO LOW 80S, MODERATE TO STRONG INSTABILITY WILL DEVELOP BY
EARLY AFTERNOON. A CAP, CENTERED AROUND 700MB, SHOULD KEEP DEEPER
CONVECTION SUPPRESSED FOR MUCH OF THE DAY. HOWEVER, AS HEIGHT FALLS
OVERSPREAD THE WARM SECTOR AFTER 21Z AND ASCENT INCREASES IN THE
RIGHT ENTRANCE REGION OF THE UPPER-LEVEL JET, THIS CAP WILL ERODE.
SIMULTANEOUSLY, EVEN RICHER LOW-LEVEL THETA-E, WITH UPPER 60S
DEWPOINTS AND MEAN MIXING RATIO IN EXCESS OF 14 G/KG WILL ADVECT
INTO THE MID-MISSISSIPPI VALLEY. THIS WILL PROVIDE AN ENVIRONMENT
FOR EXPLOSIVE SUPERCELL DEVELOPMENT GIVEN 45-55 KNOTS OF EFFECTIVE
SHEAR. IN ADDITION, LOW-LEVEL SHEAR WILL SUPPORT THE THREAT FOR
TORNADOES.

A BROAD, STRONG LOW-LEVEL JET WILL BE PRESENT ACROSS THE WARM SECTOR
FOR THE ENTIRE DAY. HOWEVER, THERE WILL BE SOME RELATIVE WEAKENING
DURING THE 18-22Z PERIOD. THIS MAY LIMIT THE TORNADO THREAT
INITIALLY, BUT BY 00Z, MOST GUIDANCE SHOWS A RENEWED LOW-LEVEL JET
STRENGTHENING AND ELONGATING OF THE HODOGRAPHS. THEREFORE, THE
PRIMARY THREAT COULD BE HAIL FOR A FEW HOURS DURING THE EVENING
BEFORE THE TORNADO THREAT INCREASES BY 23Z-00Z AND PERSISTS INTO THE
EVENING HOURS. ORIENTATION OF THE STORMS AND POTENTIAL FOR TRAINING
DO PROVIDE SOME UNCERTAINTY, BUT IN THE MOIST ENVIRONMENT, EXPECT
MULTIPLE MATURE SUPERCELLS TO PERSIST INTO THE EVENING WHEN VERY
STRONG LOW-LEVEL SHEAR DEVELOPS. MULTIPLE STRONG TO POTENTIALLY
INTENSE TORNADOES ARE POSSIBLE DURING THIS PERIOD.

..NORTH TEXAS TO THE ARKLATEX

LATE WEDNESDAY NIGHT (AFTER 06Z THU), INITIALLY ELEVATED SUPERCELLS
WILL LIKELY DEVELOP ALONG AND NORTH OF THE FRONT ACROSS NORTHWEST
TEXAS. HAIL WILL BE THE PRIMARY THREAT INITIALLY, BUT SOME DAMAGING
WIND THREAT WILL ALSO EXIST FROM THESE ELEVATED STORMS. AS THEY MOVE
EAST, AND THE FRONT STARTS TO MOVE NORTHWARD, THESE STORMS MAY
EVENTUALLY BECOME SURFACE-BASED EARLY THURSDAY MORNING ALONG THE RED
RIVER FROM NORTH-CENTRAL TEXAS TO THE ARKLATEX.

..UPPER MIDWEST TO UPPER GREAT LAKES

A CONDITIONAL, POTENTIALLY POTENT, SEVERE WEATHER THREAT COULD
MATERIALIZE ACROSS NORTHERN ILLINOIS AND INTO SOUTHERN MICHIGAN ON
WEDNESDAY. THIS AREA, CLOSER TO THE SURFACE LOW AND BENEATH THE VERY
STRONG MID-LEVEL JET STREAK, WILL HAVE A WIND PROFILE FAVORABLE FOR
ALL SEVERE WEATHER HAZARDS. HOWEVER, DESTABILIZATION WILL DEPEND
HEAVILY ON THE OVERNIGHT CONVECTION TUESDAY NIGHT FROM THE CENTRAL
PLAINS INTO MISSOURI. IF MORNING CONVECTION CAN CLEAR, AND
ESPECIALLY IF EVEN BROKEN CLOUDS CAN PERMIT SOME HEATING ACROSS SOME
OF THE REGION, A GREATER TORNADO THREAT IS POSSIBLE ACROSS PARTS OF
NORTHERN ILLINOIS.

..BENTLEY.. 04/01/2025
Click to expand...

new disco worth the read
 
D2 disco. Intense tornado potential mentioned.
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1233 PM CDT Tue Apr 01 2025

Valid 021200Z - 031200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THE
MID-MISSISSIPPI VALLEY TO THE LOWER OHIO VALLEY...

...SUMMARY...
Numerous severe storms are likely Wednesday and Wednesday night
across the southern Great Lakes, Mid Mississippi Valley, and North
Texas into the ArkLaTex. Severe wind gusts, very large hail, and
strong tornadoes are possible.

...Synopsis...
A broad mid-level trough and powerful 100+ kt jet streak will
accelerate northeastward from the central Plains to the Great Lakes
on Wednesday. Strong ascent from the advancing upper trough and
primary shortwave impulse will support a deep (~990mb) surface low
moving from the northern Plains into the western Great Lakes. A warm
front will rapidly move north through the morning which will allow
for a broad warm sector featuring 60s F dewpoints to expand as far
north as eastern Iowa to north-central Ohio/southern Michigan by
Wednesday afternoon/evening. A cold front attendant to the deep
surface cyclone will sweep eastward, with widespread strong to
severe storms expected to be ongoing along/ahead of the front at
daybreak.

...Mid Mississippi Valley to the Lower Ohio Valley...
Thunderstorms will likely be ongoing from northeast Texas to the
Upper Midwest at the beginning of the period. East of this activity,
a warm front will surge rapidly north across Illinois and Indiana
with mid 60s dewpoints expected across the Mid-Mississippi Valley to
the Lower Ohio Valley by mid-day. As temperatures warm into the
upper 70s to low 80s, moderate to strong instability will develop by
early afternoon. A cap, centered around 700mb, should keep deeper
convection suppressed for much of the day. However, as height falls
overspread the warm sector after 21Z and ascent increases in the
right entrance region of the upper-level jet, this cap will erode.
Simultaneously, even richer low-level theta-e, with upper 60s
dewpoints and mean mixing ratio in excess of 14 g/kg will advect
into the mid-Mississippi valley. This will provide an environment
for explosive supercell development given 45-55 knots of effective
shear. In addition, low-level shear will support the threat for
tornadoes.

A broad, strong low-level jet will be present across the warm sector
for the entire day. However, there will be some relative weakening
during the 18-22Z period. This may limit the tornado threat
initially, but by 00Z, most guidance shows a renewed low-level jet
strengthening and elongating of the hodographs. Therefore, the
primary threat could be hail for a few hours during the evening
before the tornado threat increases by 23Z-00Z and persists into the
evening hours. Orientation of the storms and potential for training
do provide some uncertainty, but in the moist environment, expect
multiple mature supercells to persist into the evening when very
strong low-level shear develops. Multiple strong to potentially
intense tornadoes are possible during this period.

...North Texas to the ArkLaTex...
Late Wednesday night (after 06Z Thu), initially elevated supercells
will likely develop along and north of the front across northwest
Texas. Hail will be the primary threat initially, but some damaging
wind threat will also exist from these elevated storms. As they move
east, and the front starts to move northward, these storms may
eventually become surface-based early Thursday morning along the Red
River from north-central Texas to the ArkLaTex.

...Upper Midwest to Upper Great Lakes...
A conditional, potentially potent, severe weather threat could
materialize across northern Illinois and into southern Michigan on
Wednesday. This area, closer to the surface low and beneath the very
strong mid-level jet streak, will have a wind profile favorable for
all severe weather hazards. However, destabilization will depend
heavily on the overnight convection Tuesday night from the central
Plains into Missouri. If morning convection can clear, and
especially if even broken clouds can permit some heating across some
of the region, a greater tornado threat is possible across parts of
northern Illinois.

..Bentley.. 04/01/2025
Click to expand...
 
jiharris0220 said:
Honestly this threat is definitely the most concerning for my area since the May 20th, 2019 high risk was issued.

Although even though I felt a little dread I wasn’t going nuts because the hrrr was really the only model going full supercell printer while every other model downtrended to showing no OWS storms.

This time seems different however as every CAM model is now jumping on board consistently showing OWS supercells in a primed environment.

Just hoping none of the updrafts of those supercells goes over my town, 1979 was enough already please and thank you.
Click to expand...
Yikes.. that’s saying something
 
I'll preface this post by saying in more conditional situations it's almost always better to prepare for the worst and hope for the best, and today should be treated as a potential high impact day for Oklahoma.

That being said, this forum is about discussing what we think about the weather - and there are some things that make me possibly less worried about today's forecast than perhaps what's immediately apparent on the surface.

Firstly, this setup was always going to be conditional. While the trough itself is very impressive, the ejection and just-in-time moisture have cast significant doubt even until today. Height falls range between negligible and small across the dryline and warm sector. Meanwhile the core of the 300mb jet will be displaced off to the North closer to the KS/NE border region.

1743527734567.png1743527823720.png

Essentially, this means today was always going to rely on mesoscale and boundary layer features to determine convective initiation and maintenance of supercells - especially as the environment becomes quite high CIN from about 00z onwards. While models were previously less keen on convective initiation, that has changed today, with a good number of CAMS suggesting C/SW Oklahoma initiation. As usual, asking yourself "does this make sense" w.r.t CAM output, I would actually say its a "yes"

1743528207686.png1743528282942.png

HREF guidance nicely resolves a tongue of deeper moisture and instability coincident with lower CIN in this region. Thus, I think storms are likely to initiate in that region 21-22z. and become supercellular (possibly quite quickly). However, profiles here will initially be less favorable for strong/intense tornadoes. Note the abundance of drier air, the slightly less curved low level hodograph - this appears to be a major hailer sounding. The environment will not be static, however, and low level shear will soon rapidly increase to favoring EF3+ tornadoes.

But as that happens, CIN considerably increases. Supercells will have to content with an increasingly stable, low level, dry air, and strengthening shear increasing the level of entrainment (which essentially reduces the ability of the supercell to utilize the CAPE). In some setups, storms would easily be able to take advantage of increases in shear to extreme levels - but in this particular instance I have some doubts. While the different components for EF2+ tornadoes will be present at various different points of tonight, I'm not fully convinced they will all coincide.

1743528516865.png1743528774537.png

With all that being said - there will be widespread severe weather risk tonight. Storms in OK/TX/KS will likely have very large hail, and widespread strong damaging winds. There more likely than not will be tornadoes - but in terms of seeing an outbreak of stronger tornadoes, I do think OK may have just dodged a bullet. Hopefully this is not just wishful thinking/being optimistic, time will tell... It's probably best to stay on the safe side and treat the forecast as dangerous nonetheless. I trust everyone on here is more than smart enough to follow official tornado safety guidance properly.

Tomorrow though, looks extremely concerning... and as I finish typing this all out I see the upgrade to D2 MDT on the SPC page.
 
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