General Weather Discussion - May 2015

[venture]

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[venture]

Storm Outlook...

All of this outlook is for May, so going to keep it here in this new thread.

Sunday 5/3 - Moderate instability over W OK. High CIN/Cap strenght that day however should limit all that much in the way of storm development. Best chance for anything to happen would be NW OK.

Monday 5/4 - High Instability over W OK, however it appears CIN will still be high. A bit lower over the Panhandles where precip is expected. Could see one or two storms make a run for W OK, but right now the risk still appears really limited.

Tuesday 5/5 - Instability appears to be pretty meager, but a line of storms does form in the Panhandle and marches east over night - impacting Oklahoma in the very early morning hours on Wednesday.

Wednesday 5/6 - High instability forecast for the PM, but a lot of this will depend on any on going storms from the morning line/complex. Should the atmosphere recovery fairly well, storms that form in the afternoon would be severe. Profile decent for supercells that day, but doesn't look very high end.

Thursday 5/7 - Overnight storms form a complex and shift off into Eastern OK and we should clear out pretty quickly. If that takes place, instability is expected to get very high with CAPE values near 3500 j/kg for much of Oklahoma. Forecast sounding around Norman would have a modest cap that should keep things in check until peak heating kicks in. Wind profile support rotating storms and all modes possible. Still a week out, but this could be a day to watch.

Friday 5/8 - Another severe day possible in Oklahoma, especially from Eastern into South Central. Boundary should move through the metro keep ups clear, but still can't rule things out this far away.

Tuesday 12th through Friday the 15th - Very heavy rain possible if models call this one. Severe risks seems mitigated early, but increased Thursday & Friday. I almost always expect the end of a model's forecast window to be highly erratic and change severe times.

[Anonymous.]

Projected QPF for next seven days:

[tfvc.org]

Other color meanings link changed. Weather.gov Help - Hazards Map

[John1744]

Has much changed in regards to severe threats? Or we mainly just looking at a long slow washout?

[venture]

Has much changed in regards to severe threats? Or we mainly just looking at a long slow washout?

Things have been changing in the models the last couple of runs. Need to see where it takes us. Two biggest influences is the low/trough out west and when it decides to eventually move. The other is when we'll see moisture be allowed back in the Gulf so we can see rich moisture return.

There will likely be some severe weather this week in the state. The coverage and intensity are going to be up in the air due to a long of ongoing convection through the week.

[Dessert Fox]

Are the storms after Wednesday just looking like pop up afternoon summerlike storms?

[Easy180]

Channel 9 this morning didn't seem to be too concerned about this weeks storms.

[venture]

Wednesday bears some watching. Mind you none of the upcoming events really stand out as an upper end day, but if the rights things come together we could get some pretty active days.

Wednesday still appears to be mainly west of I-35 for the better chances of severe weather - including tornadoes. The biggest factor right now is that models are predicting pretty widespread rain/storms on Tuesday that will impact things for Wednesday.

Friday, Saturday and Sunday could be a string of some of the more active days we've seen this season so far. Lot of very high instability around and the main trough kicks out overhead and comes through neutral to slightly negative.

[venture]

Near Term Severe Discussions - Blend of 12Z NAM, 06Z GFS, and 00Z ECMWF.

Today

MARGINAL RISK of severe storms for NW OK. Today relatively quiet day. By early afternoon could see some pop up showers/storms over Central into Western OK. Severe weather not expected. Additional storms will fire in the panhandles, some of which could be severe and move into NW OK through the late afternoon and evening hours.

Tuesday

MARGINAL RISK of severe storms for SW OK. Severe chances will be mitigated by convective debris from the Panhandle's monday storms. Only expecting moderate instability to build over western OK. Elsewhere in OK general showers/storms possible throughout the day.

Wednesday

SLIGHT RISK of severe storms for W OK, west of US 81. MARGINAL RISK of severe storms from US 81 to about 20-30 miles east of I-35. Very high instability expected to build in from the I-35 corridor back to the west. Some areas will see CAPE value approach 4000 j/kg. Dryline will be in play from NW OK back to the southwest into the PH. Dewpoints ahead of the dryline expected to be well into the mid 60s. Wind profiles appear to be favorable for rotating storms producing hail, high winds and tornadoes through much of the risk area. Cap will be almost non-existent to pose any issue with convective development. Challenges to Wednesday are potential for on going convection very early from Central into Eastern OK that could leave a more stabilized atmosphere in their wake as well as lack of any major focal point for storm initiation in the state - if dryline slows down or is further west than anticipated. Storms should form up by peak heating and move to the east. Could see the formation of a complex into the overnight that will move to the south into North Texas. I will note that Euro is a bit more conservative when it comes to instability but does still produce storms by peak heating at least over SW OK from Clinton to Altus and over to Lawton.

Thursday

Severe threat on Thursday seems possible, but it all depends on any on going or early convection. NAM tends to build high to very high instability back in, whereas Euro does not due to widespread on going activity. GFS is somewhere in the middle, but overall a muddled mess as well. Right now I would probably say at least a marginal level in OK if on going/morning precip is limited and the atmosphere can recover. Best chance for storms will probably be back into the panhandles and far W OK as I have a feeling we'll be stabilized in Central OK.

Extended Severe Outlook - 06Z GFS and 00Z ECMWF

Friday

Severe weather threat increases on Friday with high to very high instability predicted by both GFS and Euro. CAPE values over W OK looking like at least 2000-3000 j/kg by early afternoon. Boundary/dry line in NW OK looks to be really sharp with dews in the 60s ahead and the 20s behind. Lifted index values could exceed -10 in this area. Euro is a bit more lax on the sharpness of the boundary, so we'll just have to see. Mid to upper 60s though over nearly all of OK ahead of it. Most likely area for storm development would be Western OK north of I-40. Movement of storms would be ENE. Hail/Wind primary threat, but a couple tornadoes not out of the question with this setup. GFS has storms form into a complex and move over OKC during the evening and out east overnight.

Saturday

15% RISK of severe storms projected by SPC already, which equates to a SLIGHT RISK. Limited on going precip to impact the area on Saturday as it appears now. Euro fires storms by early afternoon and pushes them east. GFS keeps development until peak heating in the afternoon. Very little cap in place by mid afternoon should allow for storms to quickly go up and become severe. Very high to near extreme instability and favorable upper air pattern suggests all modes possible if not likely.

Sunday

We return to the game of how fast will the boundary push through. Euro has it through OKC by early to mid afternoon focusing storm development just to the east. GFS has the boundary setup and sit on top of OKC by mid afternoon. Storm development looks probably by early afternoon just west of I-35. Very high instability ahead of the boundary will make severe weather probably across this area. Once the boundary moves by, threat ends. So we'll be doing the wait and see game with this one.

Monday 5/11

Boundary starts to stall out and lose focus on Monday over SE OK. Could see a risk for some severe weather from near Wichita Falls up to Pauls Valley over to Fort Smith. Coverage should be rather limited as it appears now.

Tuesday 5/12

Moderate instability over the state south of I-40, chance of storms. Might get one or two severe ones.

Wednesday through Friday - Quiet

Sunday 5/17

Could see the atmosphere start to recharge over Central into Western OK. Storms possible.

Monday 5/18

End of the GFS forecast window, so this can always be pretty extreme, but high instability over Central and Western OK again.

[LocoAko]

Wowza -- wouldn't this be nice.

[Roger S]

Sure hope it happens.... My pond at Ardmore is still about 6' low and could use 6" of rain.

[jn1780]

Of course, even better would be for that to happen and shifted 50 miles to the west.

[Anonymous.]

Of course, even better would be for that to happen and shifted 50 miles to the west.

Yup, I wouldn't take that map's rain locations to the bank. Either way, 3-6 inches across most of OK is basically gold raining down from the skies.

[jn1780]

15% areas have been highlighted for Friday and Saturday with Saturday being mentioned as possibility being upgraded as the event approaches.

[venture]

Severe weather updates...

Today
SLIGHT RISK for extreme SW OK. MARGINAL RISK much of the Western half of OK. On going storms as expected over SW OK this morning, will continue to move East and North. We'll likely see some into Central OK later today. All modes possible in the SLIGHT risk area, but could get a couple grumpy storms in the marginal risk.

Wednesday
SLIGHT RISK in the area described earlier generally west of US 81, MARGINAL RISK from US 81 east to 20 miles east of I-35. Could start off with a few isolated storms early over South Central OK and also left over clouds from the wake of overnight storms. NAM has dryline push to the OK/TX border by mid to late afternoon before its evening retreat to the west. Euro agrees with this positioning as does GFS, mostly...GFS is a bit more undefined and not showing a sharp dryline. Instability wise everyone is showing high to very high instability over the entire risk area for tomorrow. The differences come in play as far as storm initiation. NAM wants to hold until peak heating, GFS wants to go by mid afternoon, and Euro wants to have a mix of stuff firing throughout the day. Many of these differences are due to impacts of early, on going precip and cloud cover from that activity. NAM clears out the fastest, Euro keeps us cloud covered in Central OK (and most of Western) through the entire day. So overall tomorrow is not an easy forecast. If we get more sun and align with NAM, we'll see a higher threat of severe weather with all modes possible. I would keep an eye on West Central OK tomorrow for the main tornado threat area. However, if we get stuck in clouds and a worked over atmosphere, then the chances will get reduced substantially - as seen on most risk days this year.

Thursday
SLIGHT RISK in extreme SW OK, MARGINAL RISK for all but eastern OK. Thursday appears to be two main areas of focus. One is going to be a possible early on going complex moving through Central and Southern OK early in the day. The other will be new storms firing by late afternoon in SW OK. GFS and NAM have high instability over much of the area in Western OK, GFS keeps up unstable in C OK while NAM has us pretty worked over from earlier convection. Euro isn't really aligned with either of the US models. The whole forecast for Thursday is dependent on how Wednesday turns out.

Friday
15% RISK from I-35 back to the west. Very high to extreme instability over much of the state on Friday according to NAM. GFS is much more conservative with high to very high values over North Central and much of Western OK. The big complicating factor here is the existence of a boundary on NAM coming through NW OK on Friday, whereas GFS and Euro do not have that well of a defined boundary coming in. There will likely be severe weather in OK on Friday, but right now the mess between the models is going to make it difficult to pinpoint exact areas until we see them come together. So for now it is easy to just do the broad brush stroke over the western half of the state and call it good for right now. All modes possible.

Saturday
15% RISK for all but Eastern OK. This is going to be our biggest day it seems right now. Negatively tilted trough and upper low will start to move into the area. If the trough moved east just a bit more than current projected, the risk potential on Saturday would sky rocket. As it stands now, storms will fire by Mid Afternoon in far W OK/TX PH and move east to near I-35 by early evening. Storms will be moving into an area of backing surface winds and high instability. I'll write up more on Saturday tomorrow once the NAM has this data covered in the forecast window. Right now I would not be shocked to see an upgrade to a MDT risk by the time we get into Day 2 or 3.

Sunday
This is the day the main upper storm moves over. Most of the activity though should be confined to Eastern OK, but we could see a very worked over atmosphere for storms to play in. Great potential for severe weather will probably be into SE OK and East Texas.

[Anonymous.]

Already an inch over most of the OKC metro with the heaviest batch about to come knocking now, will probably get another inch from this. Then one more big batch in the early morning hours before it all shifts east.

[venture]

Severe storm moving up through Kiowa County. Next line of storms coming in now to the Metro may have some small hail with it.

Working on website updates tonight and then will post an updated outlook a bit later.

[venture]

The national weather service in norman has issued a


* flash flood warning for...
Caddo county in southwestern oklahoma...
Comanche county in southwestern oklahoma...
Canadian county in central oklahoma...
Southeastern kiowa county in southwestern oklahoma...
Northwestern grady county in central oklahoma...


* until 245 am cdt

* at 1140 pm cdt...doppler radar indicated thunderstorms producing
heavy rain. 1 to 4 inches of rain have fallen over the past 24
hours.

[venture]

The national weather service in norman has issued a


* severe thunderstorm warning for...
Southern kingfisher county in central oklahoma...
Northwestern mcclain county in central oklahoma...
Logan county in central oklahoma...
Oklahoma county in central oklahoma...
Southwestern payne county in central oklahoma...
Eastern canadian county in central oklahoma...
Northeastern grady county in central oklahoma...
Cleveland county in central oklahoma...


* until 115 am cdt


* at 1227 am cdt...severe thunderstorms were located along a line
extending from 6 miles west of kingfisher to 6 miles northeast of
union city to near tabler...moving east at 50 mph.


Hazard...60 mph wind gusts and penny size hail.


Source...radar indicated.

[venture]

Measured 66 Mph wind near El Reno.

Pockets of intense wind in this line coming through. A lot of stuff is going to be moving around. Based on the current radar most intense areas are near Blanchard, Mustang, NW of Piedmont.

[venture]

Area of greatest concern right now moving ENE.

[venture]

At 12:37 AM, 2 N Norman [Cleveland Co, OK] PUBLIC reports TSTM WND GST of E60 MPH

[Teo9969]

The I-44 corridor is getting absolutely drenched.Probably going to see upwards of 3 inches on the night

[venture]

This image will be for this main line since midnight. Norman is getting poured on pretty good in this.