Severe weather outbreak - June 12-13 - Midwest, Mid-Atlantic

[EF-5bigj]

So what about when the LLJ kicks in?

[Stephanie]

I'm a little unnerved about the Mid-Atlantic tomorrow. I don't remember when I've ever seen TWC's forecast for my area had said "Strong Storms" in red.

The mets in our area have really been drumming the possibility of the severe weather for tomorrow in earnest today. We had a derecho blow through South Jersey almost exactly one year ago and people were without power for a week.

My thoughts and prayers for all of those in the Midwest tonight dealing with this "thing".

[Ntxw]

I think what we're seeing is training of storms along the stationary front from the southern lakes into the mid Atlantic. Not sure this is the best set up for a powerful Derecho usually with a driving front or rushing outflow, but definitely looks potent for flooding when storms travel over areas that already got drenched. I think that's what kept the long tracking tornadoes from forming today because they move into rain worked air except when they first form ahead of the storms. Tomorrow during peak heating anywhere ahead of places that haven't seen rain may experience the same conditions.

There should also be an area of enhanced turning of the winds below the low likely over Michigan and southern Ontario tomorrow that may pop some tornadoes, not certain though.

[brunota2003]

Looks like the storms are having issues, despite the insane instability in the region, to break the cap. The cap is killing anything a decent distance from the warm front. There was, at 00Z, anywhere from 2500 to 4000 j/kg CAPE across most of the region.

[angelwing]

After getting almost 6 inches Friday-Monday that just passed I am NOT looking forward to this! It's going to hit while I am traveling on the interstate....and Stephanie is right, I remember that one too! I was working in NJ at the time, it was nasty!

[CrazyC83]

IMO for tomorrow:

10% tornado across entire Mid-Atlantic, hatched roughly along and east of a DC to Harrisburg line (best shear there). Could consider a small 15% area in the Delmarva/South Jersey if confidence increases.

45% hatched wind roughly corresponding to the current Moderate Risk area, perhaps peeling off the southern part.

[CrazyC83]

Looks like the storms are having issues, despite the insane instability in the region, to break the cap. The cap is killing anything a decent distance from the warm front. There was, at 00Z, anywhere from 2500 to 4000 j/kg CAPE across most of the region.

I think the warm front is so far north which is the problem. Hence I think south of DC might struggle to get activity tomorrow.

[brunota2003]

some areas have cin of 100 to 120 j/kg...any storm, without major forcing, trying to get going has been petering out until it shifts further north.

[fogbreath]

As someone who went through the derecho last year, I'm hoping we don't wake up to a nasty surprise tomorrow morning.

But based on what my own untrained eye has been seeing and what I'm hearing from the local mets, my own gut says it will be nearly as bad as last year's by a long shot if one does form overnight.

[CrazyC83]

Derecho cranking up now!

SEL2

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 302
NWS STORM PREDICTION CENTER NORMAN OK
1150 PM EDT WED JUN 12 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHEAST INDIANA
EXTREME NORTHEAST KENTUCKY
WESTERN MARYLAND
MUCH OF OHIO
SOUTHWEST PENNSYLVANIA
CENTRAL AND NORTHERN WEST VIRGINIA
LAKE ERIE

* EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 1150
PM UNTIL 600 AM EDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

* PRIMARY THREATS INCLUDE...
NUMEROUS SIGNIFICANT DAMAGING WIND GUSTS TO 80 MPH LIKELY
SEVERAL LARGE HAIL EVENTS LIKELY WITH A FEW VERY LARGE HAIL
EVENTS TO 2 INCHES IN DIAMETER POSSIBLE
A FEW TORNADOES POSSIBLE

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 95
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTH
SOUTHEAST OF LATROBE PENNSYLVANIA TO 25 MILES WEST OF DAYTON
OHIO. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 300...WW 301...

DISCUSSION...A LARGE BOW ECHO HAS BECOME ESTABLISHED ALONG THE
IND/OH BORDER AND IS RACING EAST-SOUTHEASTWARD AT 45-50 KT. THIS
SYSTEM MAY RESULT IN A CORRIDOR OF WIDESPREAD SIGNIFICANT WIND
DAMAGE /DERECHO/ ACROSS CENTRAL OH OVER THE NEXT SEVERAL HOURS.
SURROUNDING THE CORRIDOR OF GREATEST RISK...SCATTERED SEVERE STORMS
WILL POSE A RISK OF DAMAGING WINDS AND HAIL THROUGH 10Z. AN
ISOLATED TORNADO IS ALSO POSSIBLE ALONG THE LEADING EDGE OF THE
BOW...AS WELL AS ASSOCIATED WITH DISCRETE CELLS AHEAD OF THE SYSTEM.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 28045.


...HART

[brunota2003]

Ongoing MCS is still prompting warnings for 70 to 80 mph winds...and it is finally getting away from the rain cooled air, getting into a richer environment now.

[CrazyC83]

Ongoing MCS is still prompting warnings for 70 to 80 mph winds...and it is finally getting away from the rain cooled air, getting into a richer environment now.

The key question is how long the bow echo can sustain itself. Could it become a full-blown derecho? We'll know in the morning.

[brunota2003]

Updated image of ongoing MCS, with LSR reports.



Just for grins, here is the composite reflectivity for 05Z, from the 18Z HRRR model run (note, above radar image is from 0513Z).

[Cyclenall]

As someone who went through the derecho last year, I'm hoping we don't wake up to a nasty surprise tomorrow morning.

But based on what my own untrained eye has been seeing and what I'm hearing from the local mets, my own gut says it will be nearly as bad as last year's by a long shot if one does form overnight.

What's funny is everyone who went through the June 29, 2012 Derecho all don't want this to be knocking on their door really badly. I wouldn't panic as its unlikely there would be a brutal heatwave afterwards so if power is lost for a long time, just worry about food going bad.

A PDS in the middle of the night is very impressive, this thing means business for sure. Not many in OH are going to be sleeping tonight I think.

The key question is how long the bow echo can sustain itself. Could it become a full-blown derecho? We'll know in the morning.

It would be my first morning derecho . I often wondered what it would be like to be sitting down having breakfast as intense winds rip through with black skies. Would be a neat experience.

Just for grins, here is the composite reflectivity for 05Z, from the 18Z HRRR model run (note, above radar image is from 0513Z).

If would verify if it either stayed completely stationary for 4 hours or backed up NW which is impossible (I think).

Chuck Gadica from WDIV was explaining the MCS to the south and said it stayed to the south "Thank Goodness!!"...I don't think weather lovers in that part of MI would agree . More like PO'd. Flash flooding appears to be an issue for Detroit.

These were some of the reports coming in near the start of this monster:

0420 UNK 2 E NEW KNOXVILLE AUGLAIZE OH 4049 8428 BUILDINGS DESTROYED AND TREES DOWN ALONG STATE ROUTE 219 NEAR NEIL ARMSTRONG AIRPORT. (ILN)

0425 UNK UNIOPOLIS AUGLAIZE OH 4060 8409 BUILDING DESTROYED. (ILN)

[brunota2003]

Both images are for the same time frame. The radar was from 0513Z (1:13 am EDT) and the HRRR was valid for 05Z (1 am EDT).

[Cyclenall]

:uarrow: Both images are for the same time frame. The radar was from 0513Z (1:13 am EDT) and the HRRR was valid for 05Z (1 am EDT).

Oh I see now, I got confused when you said "Just for grins" because instead of grinning I'd be impressed.

[brunota2003]

:uarrow: Both images are for the same time frame. The radar was from 0513Z (1:13 am EDT) and the HRRR was valid for 05Z (1 am EDT).

Oh I see now, I got confused when you said "Just for grins" because instead of grinning I'd be impressed.

I'd get banned if I put the actual expression down. Yes, it is impressive!

[supercane4867]

Loop

[lester]

Much of Central NC will be included in the Moderate Risk area soon.

[CrazyC83]

Here we go again...I was expecting this in the DC/Baltimore area instead?

SEL8

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 308
NWS STORM PREDICTION CENTER NORMAN OK
210 PM EDT THU JUN 13 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHERN MARYLAND
EASTERN NORTH CAROLINA
SOUTHEAST VIRGINIA
COASTAL WATERS

* EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 210 PM UNTIL
1000 PM EDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

* PRIMARY THREATS INCLUDE...
NUMEROUS SIGNIFICANT DAMAGING WIND GUSTS TO 80 MPH LIKELY
SEVERAL VERY LARGE HAIL EVENTS TO 3 INCHES IN DIAMETER POSSIBLE
A FEW TORNADOES POSSIBLE

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 90
STATUTE MILES EITHER SIDE OF A LINE FROM 20 MILES NORTH NORTHWEST
OF NORFOLK VIRGINIA TO 35 MILES SOUTH SOUTHWEST OF SOUTHERN PINES
NORTH CAROLINA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 306...WW 307...

DISCUSSION...AFTERNOON SURFACE OBSERVATIONS AND OBJECTIVE ANALYSIS
GUIDANCE INDICATE THE ENVIRONMENT FROM SOUTHEAST VA AND SOUTHERN
MARYLAND SOUTH ACROSS EASTERN NC HAS BECOME VERY UNSTABLE WITH
MLCAPE VALUES FROM 2500 TO OVER 4000 J/KG...AND DCAPE WELL IN EXCESS
OF 1000 J/KG. MEANWHILE...AREA VWP/S SHOW DEEP-LAYER WLY FLOW
INCREASING TO 50KT AT 3 KM AGL. GIVEN THIS COMBINATION OF STRONG TO
LOCALLY EXTREME CAPE...INCREASING SHEAR...AND ONGOING ORGANIZING
CONVECTIVE LINE AND FORCING IN THE PROCESS OF CRESTING THE
APPALACHIANS...A REGIONAL SEVERE WEATHER OUTBREAK APPEARS QUITE
LIKELY.

OVER THE NEXT SEVERAL HOURS EXPECT MULTICELL CLUSTERS/LINE SEGMENTS
AND SUPERCELLS TO SPREAD EAST ACROSS THE UNSTABLE WARM SECTOR WITH A
WIDE RANGE OF SEVERE WEATHER INCLUDING POTENTIALLY DAMAGING HAIL AND
PERHAPS EVEN A TORNADO OR TWO. AT THIS TIME...THE GREATEST HAZARD
APPEARS TO BE WIDESPREAD HIGH WINDS WITH THE CHANCE FOR DAMAGING
GUSTS IN EXCESS OF HURRICANE FORCE /65KT/. THE CORRIDOR OF GREATEST
SEVERE POTENTIAL WILL BE AROUND THE VA/NC BORDER AREA WITH A
DECREASING CHANCE FOR HIGHER-END SEVERE AND LOWER STORM COVERAGE
POSSIBLE WITH SOUTHWESTWARD EXTENT.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM
MOTION VECTOR 29040.


...CARBIN