Severe Weather Today

The outflow boundary has arrived but not greatly disrupted things other than a bit of cloud cover.



It did steal a great deal of CAPE, but I expect it to recover quickly. The satellite shows things already moving away allowing for some peak heating this afternoon.



Here is what the NWS is advertising...


The RUC confirms with showing the line starting this afternoon AOA 16Z.

What capping is in place will quickly erode and should be good to go with 4K+ CAPEs and no cap as this convection begins...



The CravenBrooks is still off the chart. Lets watch the sat for clouds leaving the area and keep an eye on the radar and soundings!

Friday Night Severe UPDATED

Friday Night Severe UPDATE.-

Seems should anything fire, it will be severe in the area. Huge CAPE values {4K+}, very light cap, and decent sheer…

IF they fire, which I expect they will…they will be big hail and wind producers. I don’t expect tornados as the lower wind hodographs are weak and 0-1KM helicity is fairly weak.

The only wildcard left is where the outflow boundaries will reside after the MCS tonight.

The 3PM forecast discussion for the NWS has a very good depiction of the setup…

http://www.crh.noaa.gov/product.php?site=NWS&issuedby=EAX&product=AFD&format=CI&version=1&glossary=1

If the outflow boundary is positioned such as enhancing development in this region, it would help mainly with lower level sheer and I would expect the MDT risk to shift west to include the metro.

At this point, observational data is most useful and model data will lose much value for tomorrow…

Friday Night Severe Potential?

Ok..in looking at the models from the GFS 06Z, I am seeing a couple things of interest.

First, from the upper levels, we are near the rear right quad of a jet streak, this should help with some lift.

Second, we some 500mb vorticity passing just to the north of the metro in the afternoon into evening on Friday.

Third, we have a sagging cold front, albeit weak, trailing from the NE CONUS back down through the central Plains.

This is supported by fronto being shown on the 850 mb level. There is a 850 low progged to be right on top of the surface low in central KS as part of the tail of the trailing cold front.

This should bring the LLJ just through our area ahead of the frontal zone.

The SREF advertises a bit more 500mb strength a bit further to the south through the central region of KS through the metro. This would provide adequate lift via PVA.

Below is the graphic of the CravenBrooks severe composite. Brings this area into direct focus with large values.


Looking at the Supercell Composite, it brings this potential through earlier in the day, lending me to think more of a hail/wind threat from these storms based on timing.

In looking at the Sig_Tor parameter, it also follows the Supercell Composite, but does leave a bit more potential for the metro in this composite.


Based on the soundings, it appears we have the following potential…

Date: 3 day valid 0Z SAT 31 MAY 08Station: KMCI

Precipitable water: 1.37 inches
Sfc-500 mean rel hum: 42.19 %
Est. max temperature: 32.57 C = 90.63 F
Cap Strength: 1.17 C
CAPE (B+): 2556.73 J/kg
Max Up Vert Vel: 71.51 m/s
Conv Inhibition (B-): 30.96 J/kg
Storm rel helicity (0-3000m) 127.8 m^2/s^2

Dewpoints are progged to be in the mid to upper 60s. So, based on the sounding info, I would deduce that we would have a hot and humid day, with a weakly capped environment with good instability.

The problem for tornadic development would be the SRH being 127. While it is a fair value, I would want to see it a bit higher. Sheer is adequate, but largely unidirectional.

Here is what the NWS has to say in their discussion… “A GOOD AMOUNT OF INSTABILITY AND SUFFICIENTSHEAR COULD ALLOW FOR SEVERE STORM POTENTIAL IN THE FORM OF LARGEHAIL AND DAMAGING WINDS FRIDAY AFTERNOON AND EVENING.”

I am thinking that as cells do form south of the boundary earlier in the day, these have a better chance of being supercells. Not excluding that from this area, as the day goes on into the evening, chances greatly reduce from tornadic threat to more of a linear storm structure with hail and wind being the main threat.

Lets watch so more runs, but this is my take on this upcoming event.

Saturday Setup - Sunday too?

Here we go again...

Sat looks good around Manhattan/Topeka. Huge composite scores. 60K Cravensbrooks, sig/severe, sig tor, and the composite for PW/Sheer/CAPE. All very nice.

Sunday brings it again a bit to the NE into SE Iowa.

Looking at the RUC, I see a huge swath of 4K+ CAPE values. WOW. The dryline is very distinct in the RUC right along the Manhattan down through Dodge. Dewpoints are in the low 70s with temps in the 80s.

This is purely a dryline play. Away from the dryline, too much RH and should have cloudcover.

This will play out just like today/yesterday with a light stratus shield burning off with the dryline/storms on the back side.

I think out of this, you get two - maybe three supercells before lining up.

Long Range Model Analysis

So...the ridge will break down, the energy from the ULL leaks out to the NW..and we end up with a frontal system with the surface low much to the north.

What does this mean? Not too much...for a short time, we will be in a the warm sector of the storm, but without much upper air support if any, it will be hard to get any type of large scale favorability for severe weather.

Sure, isolated storms could briefly hit severe limits and as the front comes down on Monday/Tues, we could see some linear/MCS type events..but really nothing like western KS has seen earlier this week or other set ups we have had that had more potential.

I don't see a whole lot left out there in the models after this front. I see a pretty typical summer setup building. High pressure to the SW, ridging over the central plains, and a flat jet stream up near the Canada border.

Blah. I think summer is going to quickly arrive, and I am NOT sold on a cool and wet summer at this point.

One thing of interest, the GFS wants to paint a depression or wave in the Gulf starting toward the end of next week and keeps it in frame through the duration of the model run progressing to the coast.

Who knows..maybe its time now for the tropics to get busy?

Tricky tricky tricky

The models and my based analysis tell me that nothing much will happen in this area in the next few days regarding severe weather.

Cycle analysis tells me that the potential is there from previous cycles.

Now in looking at some composites - it seems we are in the supercell and cravenbrooks targets in KS for the next few days.

This is soooo close to being a real bad situation, and when/how the ULL breaks out over the eroding ridge will tell the whole story.

If we get vorts spitting off, we will see MCS type of events that could spawn severe weather. If we see all the energy release more at one type, I think it largely misses us to the NW.

Its too close to call. Isolated large rain totals should be expected, while others get completely missed.

Sounds like late Spring in Kansas City, doesn't it? As a side note, looking at the analysis - I want to pray in advance for those in S/SW S.Central KS and N. Oklahoma for tomorrow...it could be pretty wicked on Thursday for them.

Yuck - silly pattern

Well, severe threat is minimized in this area for awhile. While we have some minor isolated heavy thunderstorms possible Thurs along the warm front, I am not seeing enough to get excited about.

We will have lingering chances of islolated thunderstorms on Fri/Sat, but the following Monday is losing its potential.

The baroclinic zone slides to our NW and the ejecting energy of the ULL goes with it. It never gets much closer than western/central KS before the surface low heads too far NW and N for us to get much from it.

By the time we get the frontogenesis, the upper air support is too weak and absent nearby.

Will keep watching as things can change...but...doesn't look like it will work out quite right.

Upcoming Monday Threat?

So, as I have been mentioning, as soon as this omega block breaks down, we should be back in business again.

Well..Sunday it erodes, and severe potential arrives on Monday with the vorticity ejecting to our NW [as mentioned in previous entries].

So, here is the map drawn up for Monday evening. Timing will be everything. If it slows down, this becomes less of a threat as surface convection will be at its least.

If it speeds up, we will have more to work with, but we get cap and moisture return. We will have to monitor..

Here is the map..

Here is the forecast sounding params...

Sounding variables and indices

1000-500 mb thick: 5761.09 m

Freezing level: 604.33 mb = 4353.76 m = 14283.83 ft

Wetbulb zero: 630.25 mb = 4012.12 m = 13162.96 ft

Precipitable water: 1.51 inches

Sfc-500 mean rel hum: 54.53 %

Est. max temperature: 33.88 C = 92.98 F

Sfc-Lift cond lev (LCL): 946.39 mb = 560.10 m = 1837.57 ft

T: 23.15 C700-500

lapse rate: 7.34 C/km

ThetaE index: 23.63 C

Layer 850.0- 500.0 mbConv cond level (CCL): 748.83 mb = 2583.79 m = 8476.90 ft

Mean mixing ratio: 14.17 g/kg Conv temperature: 37.44 C = 99.40 F

Cap Strength: 4.49 C

Lifted Index: -4.40 C Risk: Severe thunderstorms probable

Lifted Index @300 mb: -3.71 C

Lifted Index @700 mb: 1.34 C

Showalter Index: -2.93 C Risk: Severe thunderstorms possible

Total Totals Index: 52.06 C Risk: Scattered heavy thunderstorms

Vertical Totals Index: 30.11 C Cross Totals Index: 21.95 C

K Index: 35.21 Risk: > 80 % chance of thunderstorms

Sweat Index: 257.53 Risk: None

Energy Index: -3.41 Risk: Severe Thunderstorms probable

Parcel IndicesParcel: using 100 mb layerCAPE (B+): 1316.34 J/kgMax Up Vert Vel: 51.31 m/s

Conv Inhibition (B-): 245.88 J/kg

Cap Strength: 4.49 C

Lift Cond Lev (LCL): 856.88 mb = 1428.40 m = 4686.30 ft

Lev Free Conv (LFC): 661.88 mb = 3612.99 m = 11853.51 ft

Equ Level (EL): 181.88 mb = 12876.81 m = 42246.22 ft

B at Equ Level: 1295.11 J/kg

Max Parcel Lev (MPL): 111.88 mb = 15830.69 m = 51937.32 ft

Lets watch this scenerio, and capping..seems moisture will be fine in the low to mid 60s.

SW troughing

As soon as we can get this SW trough to inch closer or eject to our NW, we will see very tricky weather with temps and precip.

Once the ridging can erode in the central CONUS, which looks to be late this weekend/early Monday, the energy can eject creating surface lows forming to our NW following the weakening ridging.

Severe threats are low now for this storm and should be more to the west with more elevated type severe weather. Maybe some surface based stuff..but tough to get all the moisture and heat that far NW. Maybe this ridging will get it there.

I will be looking more to the end of this week into early next week again for severe weather when this thing ejects - unless it moves closer to us before ejecting.

Maybe look again for next Mon/Tues as it ejects for severe potential. Tough to really see anything in the models right now.

May 23rd ish - Severe Threat? - UPDATED

UPDATE - SUNDAY MORNING

Should have stuck to my gut...here is the SPC with their thoughts.

ZCZC SPCSWOD48 ALL ACUS48 KWNS 180837 SPC AC 180837 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0337 AM CDT SUN MAY 18 2008 VALID 211200Z - 261200Z ...DISCUSSION... EXTENDED MODELS -- THOUGH THEY CONTINUE TO DIFFER SOMEWHAT WITH RESPECT TO THE UPPER PATTERN EVOLUTION...PARTICULARLY LATE IN THE PERIOD -- PERSIST IN SUGGESTING A GENERAL INCREASE IN SEVERE POTENTIAL OVER THE CENTRAL CONUS DURING THE LATTER HALF OF THE UPCOMING WEEK. BOTH DEVELOP A LARGE TROUGH OVER THE WRN U.S. AND SUBSTANTIAL NWD RETURN OF RICH GULF MOISTURE INTO THE PLAINS STARTING DAY 4. WHILE SOMEWHAT MERIDIONAL...FLOW ALOFT SHOULD REMAIN STRONG ACROSS THIS REGION -- AND THEREFORE EXPECT BOTH THE KINEMATIC AND THERMODYNAMIC ENVIRONMENT TO BE SUPPORTIVE OF SEVERE STORMS. DIFFICULTY PERSISTS...HOWEVER...IN NARROWING DOWN THE REGION OF GREATER THREAT -- BOTH SPATIALLY AND TEMPORALLY -- DUE TO MODEL DIFFERENCES. ATTM...GREATEST POTENTIAL APPEARS TO EXIST DAYS 5-7 /I.E. THU. MAY 22 THROUGH SAT. MAY 24/ ACROSS PARTS OF THE CENTRAL AND NRN PLAINS. THE GFS -- WHICH DEPICTS THE UPPER RIDGE FARTHER E THAN THE ECMWF -- WOULD APPEAR TO FAVOR CENTRAL KS/CENTRAL NEB ALONG ERN FRINGES OF A FAIRLY WELL-DEVELOPED SURFACE LOW. MEANWHILE...THE ECMWF WOULD FAVOR A PRIMARY THREAT AREA FURTHER WWD -- ACROSS THE CENTRAL AND NRN HIGH PLAINS -- WITHIN SELY UPSLOPE FLOW REGIME E OF A SHARPER LEE TROUGH/LOW. ATTM...WILL INTRODUCE A THREAT AREA FOR DAYS 5-7 ACROSS MUCH OF KS/NEB AND INTO PARTS OF ERN CO/ERN WY -- COVERING PORTIONS OF THE ENVELOPE ENCLOSING SOLUTIONS FROM BOTH MODELS.

END UPDATE

UPDATE - SATURDAY EVENING

The GFS has the vorticity cutting off and never getting here. Stay tuned..the energy will have to eject somewhere/sometime..just not on next Thurs.

LOL

END UPDATE

UPDATE - SATURDAY

Models are shifting quite a bit now. Timing is up in the air and the upper air support seems to be lagging. Lets keep watching into Monday/Tues to see what is really there. I would believe based on the trends we would be seeing a cold front with some moisture return in place and convective potential. Will take a look tomorrow/Monday.

END UPDATE

UPDATE - The SPC is beginning to hint at this time period...

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0353 AM CDT FRI MAY 16 2008



VALID 191200Z - 241200Z



...DISCUSSION...

SEVERE POTENTIAL SHOULD REMAIN RELATIVELY LOW DAYS 4 AND 5...WITH A

LARGE MEAN TROUGH REMAINING OVER THE ERN HALF OF THE CONUS.



FROM DAY 6 ONWARD...BOTH THE GFS AND ECMWF SUGGEST A RETURN TO A

MORE ACTIVE SEVERE WEATHER PATTERN...AS BOTH BEGIN TO PROGRESS THE

ERN TROUGH EWD.  HOWEVER...THE MODELS DIFFER GREATLY IN THE DETAILS

OF THE PATTERN EVOLUTION...WITH THE GFS MUCH MORE PROGRESSIVE WITH

THE ERN FEATURE -- WHILE A SECOND TROUGH DEEPENS ACROSS THE CENTRAL

CONUS.



MEANWHILE...THE ERN TROUGH IS FORECAST BY THE ECMWF TO LINGER OVER

THE CANADIAN MARITIMES/NEW ENGLAND...AND THUS THE UPSTREAM TROUGH

REMAINS OVER THE ROCKIES THROUGH THE END OF THIS FORECAST PERIOD.



THEREFORE -- WHILE BOTH MODELS WOULD SUGGEST INCREASING SEVERE

POTENTIAL DURING THE SECOND HALF OF THE PERIOD...DRASTIC MODEL

DIFFERENCES PRECLUDE HIGHLIGHTING ANY SEVERE AREAS THIS FORECAST.

END UPDATE


Must be a Tues/Thursday thing. Seems like each main event lately has fallen on one of these days. Other than one Saturday, seems like things just happen on the other two days. Maybe its just me...



So, here we go again for next week. First I want to point out the similarities in the upper air to the last cycle 52-54 days ago...you know..this years cycle...LOL



Here is March 30th


.

Here is what is coming up for May 22/23rd



Notice the vorticity central Canada that cuts off due to the strong ridging to its east. Same as in March. Notice the strong flow coming into it from the big ridging in the Pacific NW?



Same picture.



So, lets get to the specifics. I took the surface map for the 22nd and drew the features...



We get into the SE quad of this cold front as it moves in. We will have to watch this as it gets closer for more defintion. I believe this is something to be watched.



For those curious about what happened 54ish days back..here is the link to the SPC for the events that day...

http://w1.spc.woc.noaa.gov/exper/archive/events/080330/index.html



Here is the forecast sounding for this day upcoming...



http://weather.admin.niu.edu/chaser/tempgif/14296.TXT



Lets keep an eye on it. The NWS is hinting at it, but somewhat dismissive due to cap potential.

We will have to see how it pans out.

Upcoming Threats

Folks, in using the chat feature, probably will use that for nowcasting events. Feel free to use it or ask questions.

Seems to work well.

Tornadic Cell - UPDATED

Folks, here is the cell that passed by near Joplin as it was further east. This is in SRV mode. I have drawn the inflow/outflow and where the couplet is. Notice the velocities in the upper left hand corner of the picture...

UPDATE...this is from the SPC for damage reports with this cell at the time the picture was captured...

2320		NEWTONIA	NEWTON	MO	3688	9419	SIGNIFICANT DAMAGE IN NEWTONIA (SGF)
2337		2 W PURDY	BARRY	MO	3682	9396	TORNADO REPORTED WEST OF PURDY MOVING EAST. (SGF)

2314

2 N NEOSHO

NEWTON

MO

3690

9437

STRUCTURAL DAMAGE NORTH OF NEOSHO. (SGF)

2259		1 W REDINGS MILL	NEWTON	MO	3702	9453	TORNADO AT INTERSECTION OF BETHEL AND IRIS ROAD WEST OF REDINGSMILL. (SGF)
2303		5 NNE SENECA	NEWTON	MO	3691	9458	TORNADO HAS STRUCK NUMEROUS RESIDENCES BETWEEN SENECA AND NEOSHO. INJURIES HAVE BEEN REPORTED. (SGF)

H

RECAP

Recap –

Sunday – I provided the setup. 96 hr. advanced warning. Look at the previous blog for the surface map drawn. Not sure I could have been any closer with timing and location.

Tuesday – I provided details.

“I think initiation starts about 21Z-0Z Thurs/Fri. I believe it will initiate just a hair to our west...not much. Maybe Lawrenceish or just north down to around Ottawa. These will be just the beginning with discrete cells filling into a line closer to 0Z. I think KC will catch the storms around 23-01Z. I believe they will gain strength as they pass. I think it may come all together in a line around Joplin up to Chilicothe. I think before they line up, they may be quasi supercellular, but would want to come together on the frontal boundary.”

Initiation was dead on. Perfect. The first storms along the dryline started at about 6PM in a line nearly right down I-35. They were supercellular and began lining up on the dryline.

They maintained peak strength right over the metro area.

This was perfect for the first pass. For the storms along the frontal boundary, we received the bow echo early morning, as it began to fill linear down south along the front. This took place almost perfectly around Chill down to Joplin, and continues to this time.

I am very happy with this forecast. Concerns about moisture and cap were mentioned, but ultimately resolved well ahead of initiation. Moisture was shallow, but enough for SCAPE and the cap was removed by the combo of CAPE and forcing.

All said, exciting storms, not too much damage and a great learning and verification exercise.