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Okay time to get the April thread underway (a little late, sorry) and we'll be starting off with severe weather. A lot of numbers are back so if you are new, here is a rough refresher of what some of them mean from SEVERE WEATHER INDICES PAGE (http://www.theweatherprediction.com/severe/indices/). Keep in mind you need multiple factors to be in place for anything to happen, so do NOT get worked up over one single value.

Parameter Review

Relation to Severe PotentialCAPE j/kgLifted Index (LI)Storm Relative HelicityBRNEHICAP*Shear 0-6kmK-IndexTotal Totals (TT)Low/Weak < 1000-1 to -3150 - 300< 10> 12+< 25 kts15 to 2540 to 52Moderate/Favorable1000-2500-4 to -7300 - 40020 to 451 to 4< 220 to 45 kts26 to 3953 to 56High/Extreme2500 +-8 or less400 + 10 to 204 + 0.5 to 235 to 100 kts40 +56 +
* CAP is always a very tricky parameter to mess with. If the cap is too weak, you get storm development easily and usually end up with a grungy mess or "crapvection" as I like to call it. If it is too strong, you don't get anything. So for higher end severe events you want a cap just strong enough to hold off development until maximum heating and instability is achieved.

Now that we are done with that review, here is the outlook for this week...

Monday

This is one of those days that could be big...if it wasn't for a cap. From the graphics below you can see that we are going to be highly unstable on Monday, but we are also going to have a CAP with a strength around 5.0...nothing is going to break that.

CAPE with SWEAT & 3km HelicityOUN Forecast Soundinghttp://www.weatherspotlight.com/screencap/2015-04/CONUS_ETA_SVR_CAPESRHSWEAT_60HR.gifhttp://www.weatherspotlight.com/screencap/2015-04/23660.GIF
Tuesday

Much the same story for Tuesday, but the dryline does shove east past the Metro area in the afternoon. CAP still forecast to be over 2 at this point, but instability will be high and can't rule out the chance for an isolated severe storm.

http://www.weatherspotlight.com/screencap/2015-04/7243.GIF

Weds/Thurs in the next post...

Wednesday

SPC already has this outlooked for much of Oklahoma at 15% severe, or or typically a Slight Risk. Dryline will be setup back to the west and approach the area just west of US 81 by early evening. Instability is expected to be quite high around 3000-3500 j/kg from Central OK back to the North. Right now GFS, which goes out to this time frame, doesn't have a ton of precip developing due to a cap (3.4) still being in place. Forcing should be a bit better with a sharper dryline though.

Main risks will be all modes. Winds will be backed over Central OK during the late afternoon and evening which enhances the potential for rotating storms. Some of the parameters a pretty impressive for what we've seen so far. LI near -7, SWEAT 528, SRH around 267, CAPE 3518, EHI at 5.6, 0-1km Shear at 21 kts (this is at the lowest level), and SRH at 204.

So what do we have working against storm development? CIN at -70 at 7PM isn't really great for storm development, but this could all change depending on what happens that day. Tornado risk also somewhat mitigated by higher LCLs (lowest cooling level) around 859 mb - or about 2500 meters off the surface.

http://www.weatherspotlight.com/screencap/2015-04/04-001.PNG

Thursday

SPC already has Eastern OK outlined in a 30% risk area, 15% for Central. Timing wise still in question a bit on how fast the dryline/front will push through. Right now GFS has it coming through the Metro by late afternoon. Won't dive into this along since we still have the other days to get through. Instability will be lower, by overall dynamics appear to be more favorable for severe storms with the main system pushing through. Right now I would expect storms to quickly fire along the boundary and race east - like we normally see this time of year. We'll just have to wait and see as we get closer.

Forecast update will be posted tonight on the 00Z models. NAM is in...GFS is in through Tuesday at this point. The quick peak at these...Monday looks pretty well capped. Tuesday...NAM keeps cap, GFS initiates storms. More details in a few.

Potential exists for a multi-day severe weather week with at least one day possibly being significant. Stay informed, don't panic or lose sleep, and just have your plan in place. Make sure your plan includes where to go should it be required for your family, including the furry four-legged members, to seek shelter. Also, something I do as well, I have a backup external drive for my PCs that I put in a "go bag" just incase we have to move. With so much of our lives on our computers now, it never hurts to have back ups. :)

One last comment before I really get into the forecast. Please...everyone...remain respectful. This section of the forums attracts both weather enthusiasts and also those who would prefer to have Sunny and 70 year round. Some people get really excited for extreme weather, others get terrified. Respect both positions and keep the snark and otherwise rude comments to a minimum. Also if you are suffering from severe anxiety when handling severe weather - stop reading. Just have your plan in place and be ready should you need to. Don't torture yourself. :) Alright, moving on to the weather...

Sunday / Near Term

Area of showers and thunderstorms moving up from North Texas. Right now it looks like most will be in Southern OK, but could see a few move up into the Metro area. No big deal, just some decent rain for a few folks - hopefully for those of us that have grass seed down. :)

Severe Risk - Negligible

Monday

Dryline starts to sharpen up over Western OK and will slowly move eastward a bit. NAM and GFS are pretty much in agreement (maybe 20 miles off) on the placement of the dryline by 7PM on Monday - roughly around US 183. Ahead of the dryline over the Central 1/3rd of OK instability will be very high to extreme. Wind profiles, instability, and the various severe indices on the forecast soundings would all point to severe weather and some on the higher end of the scale. The big fly in the ointment on this setup for Monday is the strong cape. If you followed the chart I posed earlier, cap strength is around 3.3 to 3.7 depending on the model you look at. This is going to be tough to break without any significant lift or trigger in the atmosphere. If a storm does happen to pop, and bust the cap, it'll be severe with giant hail. Is there a chance? GFS would say no. NAM...might be more flexible as it reduces CIN (convective inhibition) quite a bit just along the dryline. My expectation is we'll see a warm, mugger day with cumulous start to bubble along and ahead of the dryline. We might see one or two elevated showers try to go up and then get killed off by the cap. I can't say the severe risk is zero though, JUST in case one makes it through.

Severe Risk - Conditional between I-35 and US 183. Main risk, if storms fire, very large hail.

Tuesday

Tuesday's setup is starting to evolve as GFS has now started to show storms firing along/near/just southeast of I-44. Instability will again be very high to extreme ahead of the dryline. The key to this day producing is 1) will the cap break and 2) will storms fire early enough before the cap begins to restrengthen going into the evening hours. Of course we also need to watch for the actual placement of the dryline as well. Right now it has it right on top of OKC by 4PM and stalls it there before retreating west. Based on forecast soundings, main threats appear to be large hail and damaging winds with some pretty high LCLs (lifted condensation level, where the base of the clouds typically are...when a parcel reaches its saturation point - http://en.wikipedia.org/wiki/Lifted_condensation_level) that will keep the tornado threat down. As I'm typing this the SPC outlook hasn't gone out yet, but I expect a Marginal day at least.

Severe Risk - Conditional to Marginal along and east of I-44.

Weds & Thurs coming up...

Wednesday Discussion

Depending on what happens Tuesday, we could have some early morning storms in Central OK on Wednesday. Nothing major, just enjoy to make the forecast even more complicated. We'll get more of an idea of how things could evolve when the NAM is available tomorrow morning for this time period, but for now we are relying on the GFS. At this time it has the dryline parked in far Western OK by 1PM. Below is the imagine showing surface-based CAPE and CIN.

http://www.weatherspotlight.com/screencap/2015-04/gfsSGP_con_sbcape_090.gif

You can see how CIN is eroded ahead/along of most of the dryline will up into Kansas and all the way south to TX. CAPE values at or above 3000 j/kg all over this area. By 4PM CIN erodes even further to the east, but starts to build back around sundown (as usual). Storm initiation around 2-4PM over the NW quarter of OK...

http://climate.cod.edu/data/forecast/GFS/00/SGP/gfsSGP_prec_prec_093.gif

GFS doesn't build storms into the rest of the state until after dark, but I'm not completely on board with that - so we'll see what NAM the next couple of GFS runs show. Supercell Composite Index is pretty high for what we've seen so far this year (and really all of last year)...

http://climate.cod.edu/data/forecast/GFS/00/SGP/gfsSGP_con_scp_096.gif

I would expect Wednesday to at least be an Enhanced Risk day, but I would not be shocked to see a Moderate Risk over South Central Kansas through North Central and parts of Central OK.

Thursday Outlook

More questions, at least in my mind, on how Thursday will evolve. A lot will determine on how Wednesday turns out. Dryline movement appears to be pretty quick. It'll be in the Metro in the late morning and pushing through the Eastern 1/3rd of the state by evening. We could have on going storms through the entire morning on thursday, so that will impact how things play out. Right now, most likely area for severe weather would be in SE OK, or areas further east outside of Oklahoma.

http://climate.cod.edu/data/forecast/GFS/00/SGP/gfsSGP_prec_prec_114.gif

The NWS really seems to be for lack of a better word kind of hyping up this weeks storms. Way more warnings about staying observant and keeping safe than I've seen from them in the past.

The NWS really seems to be for lack of a better word kind of hyping up this weeks storms. Way more warnings about staying observant and keeping safe than I've seen from them in the past.

By all accounts, this is shaping up to be a high level event and I would not be shocked if somewhere in the Plains gets the first High Risk of the year.

The NWS really seems to be for lack of a better word kind of hyping up this weeks storms. Way more warnings about staying observant and keeping safe than I've seen from them in the past.

Where are you seeing this? I barely see any mention of severe weather on Norman's NWS page, forecast discussion, Facebook, or Twitter. And I agree with venture that this could be fairly high end... where perhaps alerting the public days in advance to keep an eye on this week's weather wouldn't be uncalled for.

Where are you seeing this? I barely see any mention of severe weather on Norman's NWS page, forecast discussion, Facebook, or Twitter. And I agree with venture that this could be fairly high end... where perhaps alerting the public days in advance to keep an eye on this week's weather wouldn't be uncalled for.

Hmm maybe not directly from NWS but the individuals on Twitter/Facebook that work at NWS themselves!

I'm headed to Wichita in the morning to work all week and I haven't been up there since the late 1990s - anyone with experience up there know the best local radio/television resource for weather coverage?

I'm headed to Wichita in the morning to work all week and I haven't been up there since the late 1990s - anyone with experience up there know the best local radio/television resource for weather coverage?

A few years ago KAKE 10 ABC was probably the best in Wichita KS.
They will give you good warnings.... but beyond that they are not anywhere near as good as OKC.
Asked to see your hotels storm shelter. If you don’t feel comfortable with it considered switching hotels.
Good luck.

PS:KFDI - FM 101.3 Might be your best radio bet…. But I’m not sure anymore?

00Z Model Discussion includes the continuation of the headlines we've had now regarding severe weather this week. There will be severe weather this week that may impact some population centers, so it will be important that people revisit their severe weather precautions involving both large hail and tornadoes. With that all said, I want to remind people that high end events like the one expected for this week any parameter that doesn't line up perfectly can throw the whole thing off. Whether it is the cap or moisture quality - any little thing can throw things off. Some things we need to watch for...

1) Cap. This is going to be a major player in keeping Monday and Tuesday under control, but also Wednesday could be impacted. Too weak of a cap can allow things to go early and we get a sloppy setup. Too strong and it limits things completely.

2) Upper energy speed. The key for high end events is having everything in place, that includes upper air support. The main storm system won't be on shore until late tomorrow, models won't really have a great hold on it until Tuesday morning. There is always a chance that when it is fully sampled that everything could get slowed down which throws most forecasts off.

3) Moisture return. High end events you need deep low level moisture. We already have dewpoints in the upper 60s and low 70s throughout South Texas and across most of the Gulf Coast. If that gets transported up as expected, it will go a long way in securing storm development.

With all that said, please keep in mind no one is rooting for a storm to hit your house. Any phrasing used when saying "great for storms" or something similar, is referring to the forecast itself - not that we want it happen over your head. So don't take offense. :)


Monday

Monday's severe weather outlook for Oklahoma is pretty quiet. Dryline moving into place with dewpoints well into the mid 60s ahead of oit. Instability will be very high to extreme across the area ahead of the dryline, but a stout cap should keep storms from forming. However, the chance is not zero and if one does make a run at busting the cap and succeeds then it will have a lot of instability to play with. Very large hail the main threat, but tornado threat is not zero with any storm that can go.

Images below - top row left to right: Forecast Sounding around Clinton, Moisture Convergence, CAPE and CIN forecast; bottom row: Supercell Composite, Sig Tornado Index, and Dewpoint/Lifted Index.

https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-xfp1/v/t1.0-9/10411055_609385019194155_4098125146346371182_n.jpg ?oh=9a4a29300f1de033d652e78d6116336e&oe=55ACB97C&__gda__=1438274037_140712117aa7a9adcc36713d21c12ad e


Tuesday

Tuesday's severe weather outlook for Oklahoma shows the chance for storms a bit higher than Monday. Both NAM and GFS weaken the amount of CIN in the atmosphere at peak heating, but still maintain a strong cap. GFS initiate storms along the dryline however by late afternoon from North Central to Central to Southwest OK along every storm's favorite interstate (I-44). Should storms develop, very large hail is the main threat with a tornado threat that would increase with any storms that survive into the evening as the LLJ kicks up. However, the threat isn't all that great - as it appears now - and the dryline will start retreating at that time which can usually remove needed support for the storms to survive.

https://scontent-dfw.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/11146187_609390622526928_4497669391582818876_n.png ?oh=36949844912691f1a148a0f676763cb6&oe=559E6442


Wednesday

Wednesday remains the most significant day this week for Oklahoma, as it appears now, for severe weather. Images below are for both the NAM and GFS to compare the two. Both are a little iffy on convection firing still, but the overall setup is still one that will likely produce and warrants very close watch. Timing on Wednesday is still in question for the upper storm system and whether or not it will be slower than currently projected. If it comes in slower, it throws this all off. So if we take it all at face value for now we see an environment that will be extreme unstable with CAPE values north of 4000 j/kg. We are going to have a very sharp dryline with dewpoints in the mid 60s ahead of it and into the 20s behind it in Western Oklahoma. CIN is projected to be removed by mid to late afternoon ahead of the dryline, so this will be the window for initiation.


Cap strength appears to be moderate right now, so this could easily hold convection back until peak heating kicks in when all the ingredients are perfect for the storms. Storms that form will have the risk of very large hail initially and reasonable LCLs and winds will allow for a tornado threat to increase as storms mature and the LLJ kicks in. As you can see by the forecast sounding and the Sig TOR numbers, they will be extreme for much of the time period when storms will be most active. I would like to point out that after sunset, with a strong LLJ, models always tend to go a bit crazy on the Sig TOR numbers - so keep that in mind.


One feature I pointed out on the model, and really no way for the NAM to know this ahead of time (in most cases) is the appearance of a slight bulge to the dryline on I-40 around the Clinton/Weatherford areas. This is something we need to keep an eye on because it could highlight a location where storms could pop first.


Main thing for Wednesday is don't panic or be afraid. Just get informed and have a plan. Also make sure you have at least 3 methods of getting weather warnings. Keep in mind that even with the most significant tornadoes in history that we've had here in Central OK, the overwhelming majority of people escape without injury. Just be smart and aware and you'll be okay.

https://scontent-dfw.xx.fbcdn.net/hphotos-xfa1/v/t1.0-9/11136616_609396032526387_5485953769508785817_n.png ?oh=2f2cc88a46c3b345ad16db979721f888&oe=55BBF42A

https://scontent-dfw.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/21119_609396035859720_2199416426747540183_n.jpg?oh =f150cdc5c560526c2ec543c3f486e0d9&oe=55B258AF

Run down of the SPC outlooks...

http://www.weatherspotlight.com/screencap/2015-04/06-001-outlooks.PNG

I expect Tuesday to go to at least marginal if not slight since some of the models actually produce precip tomorrow along the dryline versus today.

Looks like the systems are really lining up out there, going to be a busy next few weeks. Hopefully all of OK gets significant moisture. Western OK needs a few good soakings to give them a fighting chance this summer.

Here are some quick snapshots of the Euro 00Z run from last night. It has precip along the dryline all 3 days with very high to extreme instability.

http://www.weatherspotlight.com/screencap/2015-04/06-001-euro00z.PNG

So is this looking like a potential PDS watch kind of day? So far the TV meteorologists haven't jumped on the hype bandwagon.

Is this type of setup normal for early April? It seems to me that the triple-point setup with the dryline and stalled out cold front that takes a few days to push through is more typical of mid-late May.

So is this looking like a potential PDS watch kind of day? So far the TV meteorologists haven't jumped on the hype bandwagon.

Is this type of setup normal for early April? It seems to me that the triple-point setup with the dryline and stalled out cold front that takes a few days to push through is more typical of mid-late May.

Coverage is the main mitigating factor, more then likely, with the local media not going totally overboard yet. Though they also may finally be learning that inciting panic isn't the best thing. It's hard to say if any watches would be PDS at this point - all comes down to coverage and such. Ingredients will be in place though for a tornado to be strong (EF2+).

We'll have to see how the hi-res models handle things when we start getting into tomorrow and Wednesday.

For Today, the latest HRRR is now popping the dryline north of Lawton with an isolated supercell (and other convection) around 8PM. Movement would be ENE and enter the Metro around 10PM if things would hold together.

http://climate.cod.edu/data/forecast/HRRR/14/OKC/hrrrOKC_prec_radar_011.gif

Hmm The SPC just issued the day 2 outlook but it just has a sliver of Northern Oklahoma in the Marginal risk area this differs quite a bit from what NWS Norman has posted for us tomorrow they have a good chunk of central Oklahoma in Marginal risk. I wonder why there is so much of a difference in thinking between the 2 is for?

10589

10590

Hmm The SPC just issued the day 2 outlook but it just has a sliver of Northern Oklahoma in the Marginal risk area this differs quite a bit from what NWS Norman has posted for us tomorrow they have a good chunk of central Oklahoma in Marginal risk. I wonder why there is so much of a difference in thinking between the 2 is for?

10589

10590

The NWS Norman graphic was posted before the latest two day outlook came out. I'm sure there is a SPC team that has a meeting to discuss what the outlook is going to say and then they release it. The local forecasting team then follows suit.

Wednesday looks pretty crazy. I wonder how far south storms will fire on the dryline. The recent NAM leaves some question on whether the cap will break. My initial chase target is Northern OK around 35 to near Wichita at the triple point. I am sure that will change. I suspect storms will probably fire off however down the dryline, just how far south? We will see... I expect a moderate risk at least by tomorrow.

Dryline on the move today. Some weak CU field trying to backbuild westward around I-44 towards Lawton. Cap will probably win today, though.

Hmm The SPC just issued the day 2 outlook but it just has a sliver of Northern Oklahoma in the Marginal risk area this differs quite a bit from what NWS Norman has posted for us tomorrow they have a good chunk of central Oklahoma in Marginal risk. I wonder why there is so much of a difference in thinking between the 2 is for?


SPC seems to be a bit off with Tuesday overall. Models have been showing Tuesday as the more likely day (compared to today) to break the cap...yet today they actually had a risk area outlined.


Wednesday looks pretty crazy. I wonder how far south storms will fire on the dryline. The recent NAM leaves some question on whether the cap will break. My initial chase target is Northern OK around 35 to near Wichita at the triple point. I am sure that will change. I suspect storms will probably fire off however down the dryline, just how far south? We will see... I expect a moderate risk at least by tomorrow.

NAM has issues with convective precip, which is why it has been pretty blank when you see other models show precip forming. If I were chasing, I would play the dryline. Triple Point is easy pickings up north, and it will show with chaser convergence. Down here it'll probably be more ideal isolated photogenic stuff.


Dryline on the move today. Some weak CU field trying to backbuild westward around I-44 towards Lawton. Cap will probably win today, though.

HRRR really wants to break it, but seeing the high level clouds over that area just makes me thing it is locked in to not firing today. We'll see...only takes one.

The short range models really want to pop SW OK.

RAP

http://climate.cod.edu/data/forecast/RAP/18/FLT/rapFLT_prec_radar_005.gif

HRRR
http://climate.cod.edu/data/forecast/HRRR/19/OKC/hrrrOKC_prec_radar_004.gif

Wednesday looks pretty crazy. I wonder how far south storms will fire on the dryline. The recent NAM leaves some question on whether the cap will break. My initial chase target is Northern OK around 35 to near Wichita at the triple point. I am sure that will change. I suspect storms will probably fire off however down the dryline, just how far south? We will see... I expect a moderate risk at least by tomorrow.

Yeah, as venture noted, the NAM uses the BMJ convective scheme which can be tripped up when there is significant dry air present (which there is in the mid-levels for this event). Performs much better for deep-layer moisture events. A decent cap will be present, but I wouldn't be totally offput by the lack of QPF.

SPC maintaining a slight risk for Wednesday with some strong verbiage should storms form...

...MID MS/LOWER OH/MID AND LOWER TN VALLEYS INTO ERN KS/OK/TX...
AN EWD-MIXING DRYLINE THROUGH A MOIST/HEATING/DESTABILIZING
AFTERNOON AIRMASS ACROSS TX/OK/KS WILL REMAIN THE PRIMARY FOCUS WITH
RESPECT TO INITIATION OF SEVERE STORMS WED.

AS THE MAIN UPPER TROUGH SHIFTS ACROSS THE INTERMOUNTAIN W THROUGH
THE DAY...A WEAK LEAD WAVE/VORT LOBE PROGGED TO BE SHIFTING NEWD OUT
OF THE SRN ROCKIES TOWARD THE PLAINS INTO THE AFTERNOON SHOULD -- IN
CONJUNCTION WITH HEATING/MIXING -- HELP TO ERODE A FAIRLY STOUT CAP
AT THE BASE OF THE EML LAYER. ALL MODEL RUNS -- BOTH PARAMATERIZED
AND CONVECTION-ALLOWING -- INDICATE THAT LOCAL BREACHES OF THE CAP
WILL RESULT IN ISOLATED STORM DEVELOPMENT...BUT WHERE AND WHEN THESE
INITIAL BREACHES WILL OCCUR VARY GREATLY IN TIME AND SPACE -- FROM
CENTRAL AND ERN KS SWD TO THE TX BIG BEND...AND FROM ROUGHLY MIDDAY
THROUGH LATE AFTERNOON...DEPENDING UPON MODEL RUN. OVERALL
HOWEVER...EACH INDIVIDUAL MODEL CONTINUES TO SUGGEST ONLY ISOLATED
TO WIDELY SCATTERED STORM COVERAGE...AND THUS WILL MAINTAIN 15% RISK
AREA ATTM.

WITH THAT SAID...THE ENVIRONMENT INTO WHICH ANY OF THESE STORMS DOES
INITIATE WILL BE QUITE FAVORABLE FOR RAPID INTENSIFICATION TO
SUPERCELL MODE. WIDESPREAD MIXED-LAYER CAPE IN THE 3000 TO 4000
J/KG RANGE EXPECTED AHEAD OF THE DRYLINE WILL FUEL RAPID UPDRAFT
GROWTH...WHILE A FLOW FIELD FEATURING VEERING/STRENGTHENING FLOW
WITH HEIGHT /H5 FLOW INCREASING TO IN EXCESS OF 50 KT DURING THE
AFTERNOON/ CONTRIBUTING TO FAVORABLE SHEAR IN BOTH LOW LEVELS AND
THE DEEPER/CLOUD-BEARING LAYER SUPPORTS RAPID EVOLUTION OF UPDRAFT
ROTATION. AS A RESULT OF THESE FACTORS...RISK FOR SIGNIFICANT
SEVERE WEATHER REMAINS EVIDENT...INCLUDING VERY LARGE HAIL AND
DAMAGING WINDS ALONG WITH TORNADOES.

All modes of severe weather possible on Wednesday...evident by OUN adding the tornado category now.

http://www.srh.noaa.gov/images/fxc/oun/graphicast/image5.jpg

12Z models are rolling in...a couple quick hits...

1) Today NAM shows storms forming along the dryline from Perry North to the KS Border by 7PM. The develops more storms over Southern KS that moves through NE OK as a complex overnight into tomorrow morning.

2) Wednesday 4KM NAM shows storms initiating around 4PM along the dryline in Western OK, it races them really fast to the NE into KS by 7PM but at this point that isn't important. This is the first real indication from NAM of the cap breaking.

GFS will be out in about an hour and I'll start doing a run down of everything then.

So it sounds like this storm system is a bust for Oklahoma except the far northern counties. Still at a slight risk and the Tornado category has been knocked down from Moderate to Low so looks like we will not be having much in the way of big time severe weather in the central part of the state.

So it sounds like this storm system is a bust for Oklahoma except the far northern counties. Still at a slight risk and the Tornado category has been knocked down from Moderate to Low so looks like we will not be having much in the way of big time severe weather in the central part of the state.

Overall coverage was always a question with the cap. The NAM is just now showing the cap breaking in OK with storms by 4PM. It takes one storm to go crazy to turn it into a big day. The stance I'm taking is that the scope of tomorrow really won't be realized until we still how things start to initialize on the dryline. If we see one storms bust the cap and then start setting off additional storms, it's going to get busy fast.

SPC hasn't veered from a 15% Hatched area over Central and Northern OK.

So it sounds like this storm system is a bust for Oklahoma except the far northern counties. Still at a slight risk and the Tornado category has been knocked down from Moderate to Low so looks like we will not be having much in the way of big time severe weather in the central part of the state.

If Oklahoma is being classified as anywhere from Norman to Edmond not seeing anything then yes there is a higher chance of "bust". I wouldn't say only far northern counties will only be affected though. There is a pretty good chance storms fire north of I-40.

If Oklahoma is being classified as anywhere from Norman to Edmond not seeing anything then yes there is a higher chance of "bust". I wouldn't say only far northern counties will only be affected though. There is a pretty good chance storms fire north of I-40.

Some people just have a really narrow view. :)


I'll be in town starting Friday. I'd appreciate a storm while I'm there. Okay thanks, bye.

Next round Sat-Mon, so you should be in luck. :)

Well I was thinking it would be nice to have a little shake rattle and roll come through the south metro this evening and tomorrow. starting to get boring trying to out think the weather with this darn strong cap in place limiting storms for us.

Tuesday Discussion...

Slightly different setup compared to yesterday and one that should be more favorable for storm development. Yesterday we had a strong cap, like we do today, but we did manage to get some CU development along the dryline. However one thing I always look out for are high level clouds over the area where storms are possible. Most of the time when you see those higher clouds move in, it'll mean the cap will hold and storms won't go. Today we are pretty void of those type of clouds. We have some over South Central OK and a few remaining over the west but they are moving pretty quick and not really as thick as yesterdays. We are also already see some CU develop in western north Texas (highlighted in yellow).

http://www.weatherspotlight.com/screencap/2015-04/07-001-outlook.PNG

Other items to point out for the setup today. The dryline i starting to sharpen a good deal over NW OK and you can see the plume of moisture that is in place ahead of it - so moisture is not an issue today. The key today is eroding the cap. The Norman sounding is on the left below and shows an extreme cap in place this morning, but this should erode as the day progresses. I also highlighted the fact we are already pretty unstable as this balloon launch was at 7AM and we've had 4 hours of heating since then. SPC Mesoanalysis already has us with CAPE values 2500-3000 j/kg ahead of the dryline. So what do we have to look forward today?

Much like yesterday it is all about the cap. We'll have a bit more forcing today and more sun to help give updrafts a chance to bust the cap. The most likely area for this to happen is going to be over North Central into Northeast OK. 14Z HRRR has storms initiating in in SE KS by 7PM...it also has a lone storm in North Texas at the same time - moving Northeast. It has a bit of a hiccup showing storms along the dryline by 8PM, but I'm not going to focus it right now.

My expectations are we'll see a few areas make a run at busting the cap today. CIN will erode pretty well by late afternoon over Central OK. With the heating today we need to see how sharp the dryline stays and if moisture ahead of it stays pretty deep. These are the type of situations where it turns into a nowcasting situation since it is really hard for models to say for certain that an updraft will break the cap and we'll get a storm. If we should get one to bust through, it'll have a ton of energy to play with and we'll get some pretty large hail. Chances are better than yesterday, but they aren't extremely high. If you end up under one that does make it through you won't care about how low the chance was. :)

Wednesday Discussion...

Severe weather appears likely tomorrow still. One big question mark that is being tossed in here is how will today's activity impact tomorrow. Any storms that form could leave and outflow boundary (or multiple) around which can really impact local environments for storms. The 4km NAM kicks out the complex over NE OK tonight and if that happens, we'll likely have a boundary stretched over NE and North Central OK going into tomorrow. This can enhance areas of lift and helicity for storms, so we just need to keep an eye on things. Wednesday STILL poses a risk for significant severe weather. Do not misread the "slight" risks to mean that it isn't possible...the extent of coverage is the big limiting factor to any outlooks right now.

Looking at the setup for tomorrow afternoon/evening the NAM forecast sounding really weakens the cap to the point where it should be able to break. The forecast sounding is pretty good in that respect where it will have very high instability and a marginal cap. Severe parameters are pretty well in line with large hail and damaging wind. Tornado threat will be there and increase into the early evening hours as the LLJ increases. The indices on the right are Sig TOR (top) and Supercell Comp (bottom) at 7PM. These indices only go up as we go into the 7 to 10PM time period. Keep in mind any boundaries interacting with each other can cause for this values to be much higher in a localized area.

http://www.weatherspotlight.com/screencap/2015-04/07-001-outlook2.PNG

So let's talk time frame. 4km NAM has storms firing off along the dryline in West Central OK and North Central OK by 4PM. Most of this activity will move off to the Northeast and into KS by 7PM - at least going by this model...so don't put a lot of weight into exact positioning and timing. GFS fires off precip in North Central OK by 4PM as well, but leaves Western OK dry. Then the NAM fires off the dryline between 7PM and 10PM between US 183 and US 81...GFS doesn't do this, but I wouldn't read much into that either. The takeaway here is that models, especially the NAM which has been dry up until this point, is showing the cap breaking with development happening. It only takes one to get going and seed additional development. And again...a lot of this is all contingent on how today evolves.

http://www.weatherspotlight.com/screencap/2015-04/07-001-outlook2a.PNG

Marginal Risk remains today for North Central into Extreme Northeast OK...also the area bordering KS in NE OK has been upgraded to a Slight Risk.

Then the NAM fires off the dryline between 7PM and 10PM between US 183 and US 81

Hey Venture, where exactly is this you are referring to in your previous discussion? Trying to place these 1 highways on the map. Will this include western and SW Oklahoma? What is your confidence level of this happening as the NAM is predicting vs nothing that the GFS is showing happening?

https://www.google.com/maps/@35.4350498,-97.4427736,8z

183 is the North/South highway through Clinton...81 the N/S highway through El Reno.

I'm not 100% sold on either model. They don't handle mesoscale solutions that well which is why we normally have to look at the hi-res short term models to get a better idea on the most logical placement of storms.

SPC has upgraded tomorrow to an ENHANCED RISK over North Central to Northeast OK and through KS and MO. SLIGHT RISK remains for the entire Metro area down to Lawton and east of US 183. North Central Ok into SE KS is currently in a Hatched 30% area.

SPC has upgraded tomorrow to an ENHANCED RISK over North Central to Northeast OK and through KS and MO. SLIGHT RISK remains for the entire Metro area down to Lawton and east of US 183. North Central Ok into SE KS is currently in a Hatched 30% area.

Looks like OKC metro and points south will miss out on the big time stuff for tomorrow unfortunately

Bobby, any storm that does fire will likely be severe and more than likely a supercell. Don't get too hung up on risk categories to determine the actual severity of storms.

Bobby, any storm that does fire will likely be severe and more than likely a supercell. Don't get too hung up on risk categories to determine the actual severity of storms.

This. If you are going to try to get so specific down to w local level this far out, you are going to be wrong and your forecast look foolish.

Yeah, it is just living where I live in Moore area you get the big supercell addiction and any ordinary thunderstorm just doesn't do it for you. Homeowners ins is paid up so I am ready for them..

Yeah, it is just living where I live in Moore area you get the big supercell addiction and any ordinary thunderstorm just doesn't do it for you. Homeowners ins is paid up so I am ready for them..

Then please start a thread about this addiction. Please stop making every other post in this thread a complaint that the weather won't be severe enough for you. Let's keep this thread for actual (relevant) weather discussions.

Yeah, it is just living where I live in Moore area you get the big supercell addiction and any ordinary thunderstorm just doesn't do it for you. Homeowners ins is paid up so I am ready for them..

And then, if the area does get hit hard, everyone's rates will go up... ugly cycle.

And then, if the area does get hit hard, everyone's rates will go up... ugly cycle.

Rates are going up regardless.

Not a fan of mayhem and human misery.

Enough. Back to weather...

Instability is now extreme ahead of the dryline and CIN mostly burned off. Storms are trying to form up in North Texas, this is the area that had CIN burn off before others. Southern KS still pretty suppressed for now.
http://www.weatherspotlight.com/screencap/2015-04/sbcp.gif

http://www.weatherspotlight.com/screencap/2015-04/N_Texas.vis.gif

Looks like OKC metro and points south will miss out on the big time stuff for tomorrow unfortunately
You are a sick, sad human being.

Being that ive had 4 roofs replaced since 1998 I can do without the hail/tornadoes, any rainfall especially heavy I welcome.

Latest HRRR has storms moving into SW OK by 5-7PM tonight.

http://climate.cod.edu/data/forecast/HRRR/18/OKC/hrrrOKC_prec_radar_006.gif

Latest refresh isn't as bullish as last.

Seems to think the activity in SE KS is going to be pretty crazy. Looks like potential for severe flooding is likely up there.

HRRR is shifting south with the latest run. Currently have some CU starting to form in Major and Garfield counties. This would line up with HRRR's new initiation point...

http://climate.cod.edu/data/forecast/HRRR/20/OKC/hrrrOKC_prec_radar_003.gif

It also pops SW OK by 7PM as well...

http://climate.cod.edu/data/forecast/HRRR/20/OKC/hrrrOKC_prec_radar_005.gif

CU starting to go up in the area of interest on HRRR.

https://scontent-dfw.xx.fbcdn.net/hphotos-xta1/v/t1.0-9/11133679_610150332450957_1489296772420661076_n.png ?oh=c019cd56f702964b23ad5b11d44e0be7&oe=55ADEA90

Dam, V. You come post everything just minutes before I come to post it.

Faint CU field developing in NW TX now.

Dam, V. You come post everything just minutes before I come to post it.

Great minds and all that! :-D

Watch Likely Soon

http://www.spc.noaa.gov/products/md/mcd0219.gif

Update showing some towers going up now in Texas...based off of the shadows.

https://scontent-dfw.xx.fbcdn.net/hphotos-xfa1/v/t1.0-9/11037764_610160065783317_5004149579940231504_n.png ?oh=4dc5a26f9c91d7717e4c2c3f79eb29b0&oe=55A66A4C