Dr. Jeff Masters' WunderBlog

Sawyer, KS next in line for a nasty storm just north of the KS/OK border

Quoting PlazaRed:


Here's a few for you Keep:-

MAP 5.9 2012/04/14 19:26:42 -6.874 105.378 49.0 SUNDA STRAIT, INDONESIA

MAP 6.2 2012/04/14 10:56:19 -57.588 -65.414 9.9 DRAKE PASSAGE

And this is added to the 77Sea quakes, ( Maremotos,) we have add this week so far in this zone, a few hundred miles to the south:-

MAP 4.4 2012/04/14 18:11:17 3.443 92.801 27.2 OFF THE WEST COAST OF NORTHERN SUMATRA

AS a grazing Mare tuns into a night****?

having big problems here cpu fan keeps running on computer if i try and load anything the fan runs high forever and computer locks up had to delete all my stuff so it don't automacticly load something wrong on my end not tracking anything very limited here watching for the most part

Quoting Tazmanian:
John Woodman
SPC looking into removing PDS wording in the current tornado watches



this high risk may be a bust

Really? The main event was supposed to be later tonight...

Quoting IceCoast:


No need to apologize. In simple terms, CAPE is a measure on Instability in the atmosphere. It stands for Convective Available Potential Energy. More technically, CAPE is the amount of energy a parcel of air would have if lifted a certain distance vertically through the atmosphere. Helicity values correspond to wind values in the vertical profile of the atmosphere, such as speed and direction.

A cool visual way to look at CAPE is on a SKEW-T chart or Sounding. If we look at the most recent one from Dodge City Kansas we can see the Red line (temp), Green line (dew point) and the saturated parcel ascent i talked about above is denoted as the dashed brown line. If we calculated the area of where our parcel line (brown) first crosses to the right of the temp line(red), which is at the surface in this case until where it crosses back the left at above 200mb, that would be our CAPE value.

Okay so the higher the cape value, the lower it would cross the temperature?

It looks like one supercell, but there are actually two mesocyclones with this storm. It's actually the merger of the two cells from near Greensburg earlier.

Quoting ScottLincoln:

In very generalized terms, the taller and fatter that area is where the parcel (dashed brown) is right of the environmental temperature (red) the better for severe weather. For particular types of severe weather, it gets more specific with more specific things.

Yea that's probably the simplest way to put it for someone learning, the bigger that area the more risk. For forecasting large hail, or other types of severe weather it certainly gets more difficult, and I'm certainly no pro at it. My teacher gave us a great lab ob SKEW-T's last semester learned a bunch though!

Quoteing a bit of:-1210. SouthDadeFish

"CAPE stands for Convective Available Potential Energy and is a measure of how unstable the atmosphere is."

This is a term, I have been looking for, for decades!
Thank you so much, If I was a Bogus person, I could use this as a blogging on name!

One simple word that sums up so much, there isn't much in weather that isn't covered by that term!

Happy, Convective Atmospheric Potential Instability, CAPI.

Quoting EugeneTillman:
The Tornado Warning from the SW Iowa Storm has been downgraded to a Severe Thunderstorm Warning. Still very dangerous though.

Expected thanks for that

Honestly, I haven't been that impressed thus far from this outbreak (which is a very good thing). Seems like most of the tornado reports were very brief touchdowns. Now that doesn't mean it can't get worse, but were are approaching the traditional diurnal peak for tornado formation.

Des Moines is the capital and the most populous city in the US state of Iowa. It is also the county seat of Polk County. A small portion of the city extends into Warren County.

The five-county metropolitan area is ranked 88th in terms of population in the United States with 569,633 residents according to the 2010 count by the United States Census Bureau.[5] The city proper population was 203,433 at the 2010 census.[2]

Des Moines is a major center for the insurance industry ...In fact, Des Moines was credited with the "number one spot for U.S. insurance companies" in a Business Wire article.
http://en.wikipedia.org/wiki/Des_Moines,_Iowa

Quoting KEEPEROFTHEGATE:
having big problems here cpu fan keeps running on computer if i try and load anything the fan runs high forever and computer locks up had to delete all my stuff so it don't automacticly load something wrong on my end not tracking anything very limited here watching for the most part

Get An Hair dryer and put it on cold blow and point it into the vents on the computer. That should cool the son of the female dog down.

This storm greatly worries me

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHWESTERN BARBER AND
SOUTH CENTRAL PRATT COUNTIES UNTIL 445 PM CDT...

AT 425 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED VERY
STRONG ROTATION ASSOCIATED WITH A POSSIBLE TORNADO 2 MILES NORTH OF
LAKE CITY. THIS DANGEROUS STORM WAS MOVING NORTHEAST AT 45 MPH. LARGE
DESTRUCTIVE HAIL UP TO BASEBALL SIZE IS ALSO EXPECTED WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
LAKE CITY...
SAWYER...
MAINLY RURAL AREAS OF NORTHWESTERN BARBER AND SOUTHERN PRATT
COUNTIES.

THE ROTATION HAS INTENSIFIED SIGNIFICANTLY WITH THIS STORM, AND A
TORNADO IS LIKELY ABOUT 10 MILES SOUTHWEST OF SAWYER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3729 9900 3765 9882 3752 9850 3719 9900
TIME...MOT...LOC 2130Z 236DEG 59KT 3742 9873
HAIL 2.75IN

Taz ,so storms are fizziling out?

Quoting SouthDadeFish:
Honestly, I haven't been that impressed thus far from this outbreak (which is a very good thing). Seems like most of the tornado reports were very brief touchdowns. Now that doesn't mean it can't get worse, but were are approaching the traditional diurnal peak for tornado formation.

Well its expected to get worse as times go on into the night hours for the tornado threat. I'm pretty sure nothing has changed.

Quoting help4u:
Taz ,so storms are fizziling out?

Not at all. In fact the dry line convection has just started in OK. Its no where close to being over.

Quoting SouthDadeFish:
Honestly, I haven't been that impressed thus far from this outbreak (which is a very good thing). Seems like most of the tornado reports were very brief touchdowns. Now that doesn't mean it can't get worse, but were are approaching the traditional diurnal peak for tornado formation.

This isn't a typical tornado outbreak, the environment for strong and long-lived tornadoes will become increasingly favorable as the main wind shear and energy from the upper level low moves across the warm sector.

Quoting MAweatherboy1:
This storm greatly worries me

...A TORNADO WARNING REMAINS IN EFFECT FOR NORTHWESTERN BARBER AND
SOUTH CENTRAL PRATT COUNTIES UNTIL 445 PM CDT...

AT 425 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED VERY
STRONG ROTATION ASSOCIATED WITH A POSSIBLE TORNADO 2 MILES NORTH OF
LAKE CITY. THIS DANGEROUS STORM WAS MOVING NORTHEAST AT 45 MPH. LARGE
DESTRUCTIVE HAIL UP TO BASEBALL SIZE IS ALSO EXPECTED WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
LAKE CITY...
SAWYER...
MAINLY RURAL AREAS OF NORTHWESTERN BARBER AND SOUTHERN PRATT
COUNTIES.

THE ROTATION HAS INTENSIFIED SIGNIFICANTLY WITH THIS STORM, AND A
TORNADO IS LIKELY ABOUT 10 MILES SOUTHWEST OF SAWYER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3729 9900 3765 9882 3752 9850 3719 9900
TIME...MOT...LOC 2130Z 236DEG 59KT 3742 9873
HAIL 2.75IN

That's this one.

3.50 inch hailstones are being produced from these storms.

Quoting SouthDadeFish:
Honestly, I haven't been that impressed thus far from this outbreak (which is a very good thing). Seems like most of the tornado reports were very brief touchdowns. Now that doesn't mean it can't get worse, but were are approaching the traditional diurnal peak for tornado formation.

The missing ingredient is the crazy helicities that come with the strengthening low level jet which will be the spark for a dangerous tornadic outbreak.

Quoting TropicalAnalystwx13:

This isn't a typical tornado outbreak, the environment for strong and long-lived tornadoes will become increasingly favorable as the main wind shear and energy from the upper level low moves across the warm sector.

I understand that, but I have a feeling they may become a squall line event tonight rather than a big supercell outbreak, kind of like what happened in E Nebraska today. I don't want anyone to let their guard down, just throwing my thoughts out there.

Tafb does not have a low placed in the Central Atlantic on 18z Surface Analysis,so I wonder if it will happen at all.

Quoting weatherh98:


Okay so the higher the cape value, the lower it would cross the temperature?

Not really, quite the opposite. The the parcel line will typically cross the temp line higher up in the atmosphere with a big CAPE value. If we look at this one out of northern OK you can see it crosses slightly lower, and the total area in between the two lines is smaller resulting in a lower CAPE then the Dodge City sounding in my last post.

Quoting TropicalAnalystwx13:

This isn't a typical tornado outbreak, the environment for strong and long-lived tornadoes will become increasingly favorable as the main wind shear and energy from the upper level low moves across the warm sector.

I find it annoying that people are not realizing that the event will get worse as time goes on.

Quoting hurricane23:


The missing ingredient is the crazy helicities that come with the strengthening low level jet which will be the spark for a dangerous tornadic outbreak.

Exactly... Just wait an hour or two and the storms will really get going

Quoting hurricane23:


The missing ingredient is the crazy helicities that come with the strengthening low level jet which will be the spark for a dangerous tornadic outbreak.

To show it will get worse with time.

Now:



03Z:

Ouch

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
441 PM CDT SAT APR 14 2012

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTH CENTRAL ELLIS COUNTY IN NORTHWESTERN OKLAHOMA...
HARPER COUNTY IN NORTHWESTERN OKLAHOMA...
NORTHWESTERN WOODS COUNTY IN NORTHWESTERN OKLAHOMA...
WEST CENTRAL WOODWARD COUNTY IN NORTHWESTERN OKLAHOMA...

* UNTIL 530 PM CDT

* AT 436 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
A SEVERE THUNDERSTORM PRODUCING LARGE DESTRUCTIVE HAIL UP TO
SOFTBALL SIZE AND DAMAGING WINDS IN EXCESS OF 65 MPH. THIS STORM
WAS LOCATED NEAR GAGE...MOVING NORTHEAST AT 80 MPH.

* LOCATIONS IMPACTED INCLUDE...
BUFFALO...GAGE...FORT SUPPLY...FARGO...MAY...SELMAN AND TANGIER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH NO WARNING. GET
TO A STORM SHELTER OR STURDY BUILDING IF A TORNADO APPROACHES.

LARGE DAMAGING HAIL IS LIKELY. TAKE SHELTER NOW IN A STURDY
BUILDING AND STAY AWAY FROM WINDOWS.

&&

LAT...LON 3624 9953 3629 9984 3636 9983 3698 9963
3700 9961 3700 9908
TIME...MOT...LOC 2136Z 205DEG 69KT 3629 9971

$$

Quoting weatherh98:


Okay so the higher the cape value, the lower it would cross the temperature?

Not always. The elevation where the parcel path crosses the environmental temperature is called the Level of Free Convection.

The lower that is, the easier it is to get storms going. It is also one of the two parameters that can be used to estimate the elevation of the storm base.

Think of this example... if you have a cold front moving through that is supposed to create storms, it must lift the warm, humid air from the surface past the LFC before storms will form. Once the warm, humid surface air reaches the LFC, it will freely climb into the atmosphere as an updraft. If the LFC is low, a weaker front could do it, if the LFC is high, it takes a stronger front. Generally-speaking.

Quoting IceCoast:


Not really, quite the opposite. The the parcel line will typically cross the temp line higher up in the atmosphere with a big CAPE value. If we look at this one out of northern OK you can see it crosses slightly lower, and the total area in between the two lines is smaller resulting in a lower CAPE then the Dodge City sounding in my last post.

So then what is the "number" based on

Quoting hurricane23:


The missing ingredient is the crazy helicities that come with the strengthening low level jet which will be the spark for a dangerous tornadic outbreak.

Possibly Adrian. It doesn't get much worse than tornadoes at night.

Helicity Analysis:



Strongest helicity is currently east of the supercells.

Quoting SouthDadeFish:
I understand that, but I have a feeling they may become a squall line event tonight rather than a big supercell outbreak, kind of like what happened in E Nebraska today. I don't want anyone to let their guard down, just throwing my thoughts out there.

Dave, at some point it will but its most likely a long way off. The stronger cells with the dry line are killing the weaker ones near by as time goes on. So as it may seem like it may be forming a line in OK most of those storms will die off while a few will survive and prosper. That is what I have been seeing so far and I believe it will continue.

Quoting ScottLincoln:


Not always. The elevation where the parcel path crosses the environmental temperature is called the Level of Free Convection.

The lower that is, the easier it is to get storms going. It is also one of the two parameters that can be used to estimate the elevation of the storm base.

Think of this example... if you have a cold front moving through that is supposed to create storms, it must lift the warm, humid air from the surface past the LFC before storms will form. Once the warm, humid surface air reaches the LFC, it will freely climb into the atmosphere as an updraft. If the LFC is low, a weaker front could do it, if the LFC is high, it takes a stronger front. Generally-speaking.

Oh I see

Quoting weatherh98:


So then what is the "number" based on

The number is an integration, is the area between the parcel path and the environmental temperature. Think... calculus.

Quoting TropicalAnalystwx13:

To show it will get worse with time.

Now:



03Z:

Well if the NAM is right that may change things.

Quoting SouthDadeFish:
Possibly Adrian. It doesn't get much worse than tornadoes at night.

Helicity Analysis:

Give it another 2hrs or so trust me.

Quoting hurricane23:


The missing ingredient is the crazy helicities that come with the strengthening low level jet which will be the spark for a dangerous tornadic outbreak.

And we want it to stay missing until at least tomorrow lunch time?

Quoting TropicalAnalystwx13:

This isn't a typical tornado outbreak, the environment for strong and long-lived tornadoes will become increasingly favorable as the main wind shear and energy from the upper level low moves across the warm sector.

Hey, I've been out most of the day and heard about high risk this morning. When will this outbreak really take off? I do know there's multiple PDS watches now, though.

Quoting hurricane23:


Give it another 2hrs or so trust me.

We'll see my friend. You very well may be correct. For the sake of those living in the Plains I hope not.

I dont know who will want to be a spotter tonight especially when things will be at its worst in the plains--do they even chase at night?

290
WFUS53 KDDC 142150
TORDDC
KSC007-033-142215-
/O.NEW.KDDC.TO.W.0024.120414T2150Z-120414T2215Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DODGE CITY KS
450 PM CDT SAT APR 14 2012

THE NATIONAL WEATHER SERVICE IN DODGE CITY HAS ISSUED A

* TORNADO WARNING FOR...
BARBER COUNTY IN SOUTH CENTRAL KANSAS...
SOUTHEASTERN COMANCHE COUNTY IN SOUTH CENTRAL KANSAS...

* UNTIL 515 PM CDT

* AT 444 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY STRONG ROTATION ASSOCIATED WITH A POSSIBLE TORNADO 10 MILES
SOUTH OF AETNA. THIS DANGEROUS STORM WAS MOVING NORTHEAST AT 50
MPH. DESTRUCTIVE HAIL UP TO TWO INCHES IN DIAMETER IS ALSO EXPECTED
WITH THIS STORM. HAIL UP TO 2 INCHES IN DIAMETER IS ALSO POSSIBLE
WITH THIS STORM.

* LOCATIONS IMPACTED INCLUDE...
AETNA...HARDTNER...MEDICINE LODGE...SHARON AND HAZELTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.



LAT...LON 3699 9861 3699 9909 3700 9909 3742 9865
3728 9834 3711 9834
TIME...MOT...LOC 2149Z 226DEG 48KT 3698 9895
HAIL 2.00IN

Quoting Bluestorm5:
Hey, I've been out most of the day and heard about high risk this morning. When will this outbreak really take off? I do know there's multiple PDS watches now, though.

At or around 0Z, it is likely things will get crazy.

Quoting ncstorm:
I dont know who will want to be a spotter tonight especially when things will be at its worst in the plains--do they even chase at night?

Many do.

Quoting SouthDadeFish:
We'll see my friend. You very well may be correct. For the sake of those living in the Plains I hope not.

With these strong cells currently firing along the dryline in time they should propagate into the best environment right around 8pm.

Quoting ScottLincoln:


The number is an integration, is the area between the parcel path and the environmental temperature. Think... calculus.

That's hard when you are in algebra 1 honors:)

Tail beginning to move South.

Quoting weatherh98:


Oh I see

If you're really feeling ambitious and want to learn more here are a few links from my course last semester going over soundings and severe thunderstorm indices.

Link
Link

Well we're up to 19 tornado reports: