12Z NAM is done and I'm not really sure how to handle the whole thing with the handling of boundaries.

Saturday is how everything has been lining up for awhile...dryline out in W OK.

Sunday is blasts the cold front in almost all the way to I-44 in OKC back through Altus and Hollis by evening and a dryline near LAW by evening.

Monday is has the boundary along I-44 from NE OK to OKC and almost directly south to around Duncan.

Something just not sitting right with this scenario. Looking at the SPC's SREF, which is an ensemble of all the short range models, it seems to indicate the NAM is an outlier in this.

GFS is pretty similar to all previous runs, so I'm going to go with it. NCEP hasn't updated their model guidance message yet, but for the 00Z runs last night they were throwing the NAM runs completely in the garbage. We'll see if they keep with that thinking. More in a few as I go through GFS data.

NCEP has updated their discussion and they came out like I expected...NAM is too fast and garbage right now.


...DEEP CYCLONE MOVING FROM THE WEST INTO THE PLAINS...

PREFERENCE: BLEND OF 12Z GFS AND 00Z ECMWF/CANADIAN


ASIDE FROM THE NAM BEING MUCH FASTER THAN THE GLOBAL MODELS AT THE
SURFACE...THERE IS GOOD AGREEMENT ON THIS SYSTEM THROUGH DAY 3.
THE NAM FORECAST BECOMES TOO FAST AT SURFACE BY THE END OF DAY 2.
THE GFS APPEARS SLIGHTLY FAST ALOFT WITH THE LEAD WAVE EJECTING TO
THE MID MISSOURI VALLEY AND UPPER MIDWEST. THE GFS ALSO OFFERS A
SHARPER TRAILING WAVE THROUGH THE FOUR CORNERS AREA ON DAY 3.
DIFFERENCES ALONG THE LENGTH OF THE PACIFIC FRONT AND ELONGATED
ZONE OF LOW PRESSURE ARE LESS PRONOUNCED BETWEEN THE 12Z GFS AND
00Z ECMWF/CANADIAN RUNS. THE 00Z UKMET ALSO AGREES TO A LARGE
EXTENT EXCEPT FOR ITS DEVELOPMENT OF SURFACE WAVE APPROACHING
SOUTHWEST MISSOURI LATE MONDAY.

Should we be more concerned about discrete supercells in the OKC area on Monday than on Sunday?

A lot of images and text coming with the discussions for the upcoming event, so I apologize in advance. :) Everything will be consolidated into one post here: http://www.weatherspotlight.com/?p=265

Saturday May 18th


I'm going to split this up a bit since we have two areas of interest when it comes to population. Those along the dryline and the higher populated Central OK area. The setup has the dryline stretched over far western OK. Instability will be very high to extreme across much of Oklahoma, but the cap will also play a significant factor as well. The best chance for storms to develop will be over NW OK which will then spread along the OK/KS border. The secondary area to watch is further south in West Central and SW OK. Higher helicity values are here and what would appear to be a slight bulge to the dryline that could help break the cap. Any storms that form in this area will be severe and could go up very quickly once the cap is compromised.


The Clinton forecast sounding is pretty favorable for severe right turning storms with large hail and damaging winds. LCL levels are pretty high up so the tornado threat could be mitigated unless better low level moisture works in. CIN of 157 will be tough to break, but if it does work out then all other indices are in line to support the potential severe threat. Should anything move into Central OK the Norman forecast sounding shows a much more unstable environment and much better low level moisture. We very well could see the storms start off as high based supercells with monster hail and transition into a tornado threat as they approach Central OK. All indices in Central OK are off the charts if a storm can develop or move into the area. Right now the risk looks low based on the cap and the fact that convection temps are around 100 to 103, which is the air temp needed to get a parcel of air to rise and break the cap.


http://www.weatherspotlight.com/screencap/outlooks/may13/18-gfs-1.png

Norman forecast sounding...
http://beta.wxcaster.com/skewts/GFS-test/036/SKT_GFS__KOUN.png

Clinton Forecast Sounding...
http://beta.wxcaster.com/skewts/GFS-test/036/SKT_GFS__kcsm.png

Sunday May 19th


The first significant day of this event, potentially, as things ramp up with better upper air support and a continued escalation of severe indices. Setup for Sunday has a couple boundaries to initially play with, but we need to keep in mind that any left over boundaries from storms on Saturday will have to take into account. This can really complicate the forecast, but we won't know the setup until we get there. The dryline will make a push for Central OK but will only make it to about US 183. An area of significant instability and shear could develop in the classic tornado alley of I-44 from OKC to Lawton. Storm coverage could still be limited, but anything that develops is going to be severe with the chance for high end severe weather including strong tornadoes and very large hail.


Forecast sounding from Norman for this period doesn't have much going against it. A few things that stand out are LCLs in the upper 800s could make it difficult for tornadoes to get going, but that should be overcome pretty quickly. CIN is less than 100, so that could delay things a bit but is easily able to be overcome. Hodograph is ideal for right turning supercells. Directional and speed shear are very good.
Sunday has been advertised to be significant for awhile, nothing is change as of right now.


http://www.weatherspotlight.com/screencap/outlooks/may13/19-gfs-1.png


http://beta.wxcaster.com/skewts/GFS-test/060/SKT_GFS__KOUN.png

Monday May 20th


Day 2 of potentially significant severe weather and day 3 of the overall event. Like Sunday, prior day events and boundaries are going to play into what happens. Frontal boundary should be through NW OK and the dryline extending south from it through West Central Oklahoma right around US 183. Strong instability again with a favorable shear environment in the I-44 corridor. Overall the environment is pretty close to Sunday, maybe a little better is some factors and worse in others - so a wash.


http://www.weatherspotlight.com/screencap/outlooks/may13/20-gfs-1.png



http://beta.wxcaster.com/skewts/GFS-test/084/SKT_GFS__KOUN.png


Tuesday May 21st


This is a more transitional day as the frontal boundary will slide to the SE roughly along I-44. Instability will be high to very high ahead of it. Tuesday could be significant as well depends on the previous days, of course. The front will be very close to the OKC metro area so its a tough call on exactly how it'll work out. Forecast sounding from Norman would indicate a more linear wind pattern which would limit any tornado threat, but its all going to come down on the placement of the boundary. Large hail and damaging winds are the biggest threat right now, but further ahead of the boundary will see a higher tornado risk.


http://www.weatherspotlight.com/screencap/outlooks/may13/21-gfs-1.png



http://beta.wxcaster.com/skewts/GFS-test/108/SKT_GFS__KOUN.png

SPC's new Day 2 Outlook is out and now has Western and parts of Central (including most of Metro area) Oklahoma in the Slight risk.

Ch. 4 KFOR says on it noon WXcast that the tornado threat goes way up on Sunday in central, north central and north eastern Oklahoma.

Anyone else fascinated with visible satellite imagery right now? This low deck of clouds is hugging along the border of OK/TX pandhandle and sweeps across the state.

I always find it crazy how often times weather seems to react to our imaginary boundaries. Coincidental things like this are neat.

Anyone else fascinated with visible satellite imagery right now? This low deck of clouds is hugging along the border of OK/TX pandhandle and sweeps across the state.

I always find it crazy how often times weather seems to react to our imaginary boundaries. Coincidental things like this are neat.

I look at it as Mother Nature saying "Oh you originally forecasted highs today near 90 and dry? I'll show you who's in charge." :)

Ch. 4 KFOR says on it noon WXcast that the tornado threat goes way up on Sunday in central, north central and north eastern Oklahoma.

I find it kind of funny how Venture and Anonymous gives these long detailed scientific analysis's and then someone post something about how KFOR, KWTV, and KOCO says there will be a threat of tornados this weekend. Well yeah, but we already know what their saying. That doesn't mean anything to us here(I mean they don't give their reasoning why they say that) Do people really value the local tv meterologist that much even after reading a thread like this filled with detailed information?

I find it kind of funny how Venture and Anonymous gives these long detailed scientific analysis's and then someone post something about how KFOR, KWTV, and KOCO says there will be a threat of tornados this weekend. Well yeah, but we already know what their saying. That doesn't mean anything to us here(I mean they don't give their reasoning why they say that) Do people really value the local tv meterologist that much even after reading a thread like this filled with detailed information?

Yes, it means something and this is why.
WX forecasts are a lot like opinions with their own take on what might happen.

This isn’t about who’s wrong or right. I don’t play that game but there are different levels of skills and different interpretations on a forecast. Not every WX forecaster is going to bat 1000% all the time and they all know this.

Posting the same or different thoughts on forecasts lets people know there is consensus or an opinion that is different… allowing the readers be more informed about all the possibilities. Personally, I want to know about all reasonable possibilities and I suspect there are others too, including the various WX forecasters.

I have had several hours of meteorology and have chased many years ago but my level of meteorology is nowhere close to Venture and Anonymous. I very much appreciate both for what they do here. When there is a topic of interest where somebody knows more than me I usually enjoy learning more from them and that the case for me in this thread.

This coming week is going to be very active. The tail end of this storm system is going to be throwing out waves of energy all week long.

GFS painting daily events even out to Wednesday. With some short-wave action heading into the next weekend possible.


Spring time in OK always helps to re affirm my love for this part of the nation. Every. Damn. Year. (minus 2005, LOL!)

With regards to tomorrows Saturday's severe weather do you think the feature comming up our way from down in Mexico could have an effect on the level of severe we have tomorrow? are people overlooking this feature as it can play a role as well. The NWS keeps pushing the severe lne closer to the I-35 coridor in there latest outlook for Saturday. Thoughts?

http://www.srh.noaa.gov/images/fxc/oun/graphicast/image6.jpg

http://www.srh.noaa.gov/images/fxc/oun/graphicast/image1.jpg

http://www.srh.noaa.gov/images/fxc/oun/graphicast/image6.jpg

I hope we don't get severe weather sunday, that's when my post graduation party is :(

I hope we don't get severe weather sunday, that's when my post graduation party is :(



I would say that the likelihood of a serious severer weather event including a possibility of tornadoes in central Oklahoma is almost a sure bet. You should IMHO have a reliable action plan in place for all activities from midafternoon on.
JMHO

A suggestion to the TV folks.


If the Sunday threat is as serious as it now appears it would be helpful to the public if the TV stations had a brief WX update at noon, after they have seen the latest updated information.
The TV stations should super impose the time of their planed WX updates so more people will watch and provide updates every hour or as conditions warrant about the dynamics of the WX event well before any watches are issued.

Really quick, I setup this thread: http://www.okctalk.com/arts-entertainment/33784-okc-weather-coverage-wars-2013-a.html To talk about the local OCMs and other on camera personalities. So let's not get too far down the road in here arguing about them. :)



Why is this so hard for people to do? Geez.........

Why is this so hard for people to do? Geez.........

Nature of the beast to have everything flow together. At least separating out the media related debate is an easy one, IMO.

Why is this so hard for people to do? Geez.........


That’s why I was sticking to the WX opinions of WX people and not their strengths, weakness and popularity on TV

Getting some storm development now in Western North Texas along the dryline. Very slight chance this build up into SW OK tonight.

Wow. Beautiful supercells just blossoming, stationary at this time.

This is what could happen tomorrow and Sunday, as the dryline retreats back west, it could fire off a few cells. Any bulge will enhance this feature and possibility.

Here is the Archer County storm...pretty storm.

http://www.weatherspotlight.com/screencap/may13/kfdr_20130517_2250.png

Missed this. This is going to be that area of rotation that I was pointing out that night and wasn't sure if it was just strong winds. :)

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
838 AM CDT FRI MAY 17 2013


..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..


0634 PM TORNADO 3 W ADA 34.78N 96.71W
05/15/2013 PONTOTOC OK NWS STORM SURVEY


AN F0 TORNADO DEVELOPED JUST WEST OF THE CITY OF ADA AND
MOVED NORTHEAST ABOUT ONE MILE. A MOBILE HOME WAS DAMAGED
NEAR THE BEGINNING OF THE TORNADO PATH AND TREES WERE
SNAPPED OR UPROOTED ALONG THE PATH.

What does the overnight forecast look like for Sunday into Monday in Central and Eastern Oklahoma? Will these storms die off after dark or will they continue overnight?

What does the overnight forecast look like for Sunday into Monday in Central and Eastern Oklahoma? Will these storms die off after dark or will they continue overnight?

It's quite possible we'll see storms continue overnight, especially east of I-35. West of I-35 should quiet down and recharge for Monday.

I watched News9 tonight for weather because none of their forecasters wear bedazzled ties and Gary acted as if nothing big is going to happen. That's the kind of forecasting I like!

I watched News9 tonight for weather because none of their forecasters wear bedazzled ties and Gary acted as if nothing big is going to happen. That's the kind of forecasting I like!

I hope he is right.

I watched News9 tonight for weather because none of their forecasters wear bedazzled ties and Gary acted as if nothing big is going to happen. That's the kind of forecasting I like!

Just watched his newscast so I can put it into context, since sometimes you need to read between the lines. Didn't get the "nothing big is going to happen" at all. This seems to play with what we saw with the Texas tornadoes a couple days ago. That was a slight risk and we still saw 16 tornadoes and an EF4. What Gary is trying to relay is that, especially tomorrow, it shouldn't be too widespread so don't cancel plans. However, what does develop will be severe and it could be significant. People get in their head that it's only a "slight risk" and that it isn't a big deal, until they have a 2x4 flying at their head and you realize you screwed up by not taking the setup seriously.

Gary simply was stating the facts that in higher end setups you can always have one factor take over and bust the whole day. For this event that will be the cap. Is it going to happen? Ehhh, its not looking too likely at this point. Tonight was a good indication of just how much juice is out there already to get these things going. He also is saying it knowing that the warning lead time we have in this state is better than any other with the saturation of weather professionals, storm spotters, chasers, and media.

Tomorrow's discussion coming up in a bit.

Make sure your weather radio is ready to go.

Outlook for Saturday hasn't really changed much. I'm going with a blend of the SREF, NAM and GFS for this since everything is close - for the most part. Ensemble guidance has precip chances starting around 4PM out near the OK/TX border in NW OK and also near LAW in SW OK. This activity is forecast to expand and build towards I-35 by 7PM and continue through about 1AM on Sunday. It appears storms will probably start out as more high based hailers with damaging winds. The hail risk will be quite high tomorrow with sizes exceeding 2" in many cases. As we get later in the evening, the LLJ will kick in as it normally does and we'll see conditions for tornadoes in NW OK increase. If we see high quality low level moisture tomorrow, the tornado threat will kick off earlier with the isolated supercells that develop. Potential will exist for strong tornadoes especially NW. We could see a secondary area of favorability for strong tornadoes develop in SW OK from the OKC area to LAW.

Both NAM and GFS highlight a dryline bulge tomorrow, but are not in agreement on the area. NAM pushes this in through West Central OK with the apex in eastern Custer Co. GFS is farther south and puts this area near Lawton. Wherever this takes place, if it does, will be an area of enhanced convergence and a higher probability of a storm breaking the cap. This will also enhance the directional shear of that localized environment by providing a strong SE wind component to go against the more SW/WSW 500 mb wind.

KOUN forecast sounding for tomorrow is still very favorable for supercells to form, but the tornado threat isn't extremely high. As I mentioned earlier, higher LCLs around the 820 mb level will be something that needs to be overcome. Typically I like seeing that more around 900 mb or lower (higher number). Cap Strength tomorrow is forecast to be 4.7 which is pretty stout and would normally hold back storms most days, but if we get the dryline bulge, then enough convergence could take place to bust it. If we look closer to the dryline at the soundings for LAW and OJA (Weatherford) the cap is pretty much nonexistent in those areas and convective temps are lower around 98°F which many areas will be able to reach tomorrow. LCLs though are higher up further west, so that would temper things a bit I would imagine.

So the main summary for tomorrow, since after this I'll step back and see how things unfold and get into a more "Nowcasting" mode and relaying official NWS information, is that there will be a good chance for a few isolated storms to bust the cap along the dryline tomorrow. Any storms that do go up will have the chance to produce hail over 2" in diameter, winds over 70 mph, and tornadoes some of which could be strong. Nothing is locked in per se, but that's the way it looks now.

http://www.weatherspotlight.com/screencap/outlooks/may13/18-nam-1.png

http://www.weatherspotlight.com/screencap/outlooks/may13/18-gfs-2.png

NOAA Severe Weather Update - 05/17/13 10pm
NWS Norman

Severe Weather Update - 05/17/13 10pm - YouTube (http://www.youtube.com/watch?v=wY4WDL6hhPQ&feature=youtu.be)

I am loving the gulf moisture out there tonight. I wish it wasn't indicative of such bad weather for Oklahoma. It's making me incredibly homesick for the east coast just standing out in it.

Anyone else getting real tired of Mike Morgan mentioning Reed Timmer and the Dominator every other sentence?

I am loving the gulf moisture out there tonight. I wish it wasn't indicative of such bad weather for Oklahoma. It's making me incredibly homesick for the east coast just standing out in it.

I am in Dallas and am planning to drive back to OKC tomorrow afternoon. Plan on leaving around 2:00 pm. Do you think we can make it home before things get going?

This is the first time I have posted so I am not sure I am doing in correctly.

Anyone else getting real tired of Mike Morgan mentioning Reed Timmer and the Dominator every other sentence?

No.

MDT risk now includes Western OK...

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1254 AM CDT SAT MAY 18 2013

VALID 181200Z - 191200Z

...THERE IS A MDT RISK OF SVR TSTMS FOR PARTS OF WRN OK AND WRN KS...

...THERE IS A SLGT RISK OF SVR TSTMS FOR A LARGE PORTION OF THE PLAINS STATES...

...AN ACTIVE SEVERE WEATHER DAY IS EXPECTED OVER A LARGE PORTION OF THE PLAINS. LARGE DESTRUCTIVE HAIL AND THE POSSIBILITY FOR A FEW STRONG TORNADOES ARE THE MAIN THREATS...

...SYNOPSIS...
INCREASING CYCLONIC MID-UPPER FLOW WILL OVERSPREAD MUCH OF THE PLAINS THROUGH THE DAY 1 PERIOD DOWNSTREAM OF AN APPROACHING LARGER SCALE WRN U.S. TROUGH. THE PRIMARY UPPER TROUGH AXIS WILL MOVE FROM THE GREAT BASIN TO THE CNTRL ROCKIES-SRN HIGH PLAINS BY SUNDAY MORNING. AN ELONGATED LEE TROUGH WILL CONSOLIDATE INTO A LOW FORECAST INVOF THE ERN CO/WRN KS BORDER BY 00Z/19. A MOISTURE RICH RESERVOIR OVER THE SRN PLAINS WILL CONTINUE TO BE DRAWN NWWD INTO PORTIONS OF THE CNTRL HIGH PLAINS E OF A SHARPENING DRYLINE BY AFTERNOON. SEVERE STORMS ARE EXPECTED TO DEVELOP DURING THE AFTERNOON-EVENING HOURS WITH SOME OF THESE STORMS CONTINUING WELL AFTER DARK.

...PLAINS...
FRIDAY EVENING WATER VAPOR IMAGERY SHOWS A LEAD SHORTWAVE TROUGH OVER SRN NM AND THIS FEATURE IS FORECAST TO MOVE INTO CNTRL KS-OK BY EARLY-MID AFTERNOON. DESPITE IMPLIED SUBSIDENCE IN ITS WAKE...THE APPROACH OF THE LARGER SCALE TROUGH AND ASSOCIATED HEIGHT FALLS /FORCING FOR ASCENT/ WILL OVERSPREAD THE HIGH PLAINS DURING THE AFTERNOON-EVENING. BENEATH THE STOUT EML...HIGH QUALITY BOUNDARY LAYER MOISTURE SAMPLED BY RAOBS OVER THE SRN PLAINS FRIDAY EVENING
/15-16 G/KG 100MB MEAN MIXING RATIO/...WILL LEAD TO DEWPOINTS RANGING FROM THE LOWER 60S OVER THE DAKOTAS TO THE UPPER 60S AND LOWER 70S FARTHER S OVER OK/KS BY MID AFTERNOON. STRONG DIABATIC HEATING ALONG THE DRYLINE WILL CONSIDERABLY WEAKEN AN INITIALLY STOUT CAP BY MID-LATE AFTERNOON. VERY STEEP MID LEVEL LAPSE RATES IN EXCESS OF 8-9 DEG C/KM IN COMBINATION WITH THIS RICH MOISTURE WILL CONTRIBUTE TO MODERATE INSTABILITY OVER PARTS OF THE NRN PLAINS TO EXTREME INSTABILITY /4000-5000 J/KG MLCAPE/ OVER PARTS OF KS INTO NWRN TX.

ONCE THE CAP IS ERODED IN POCKETS ALONG THE DRYLINE...EXPLOSIVE UPDRAFTS WILL RAPIDLY BECOME SEVERE AND INITIALLY FAVOR LARGE TO VERY LARGE HAIL AND DMGG WINDS. SUFFICIENT DEEP LAYER SHEAR /RANGING FROM AROUND 30 KT FROM NWRN TX TO WELL INTO THE SUPERCELL RANGE FROM KS NWD/ WILL PROMOTE DISCRETE SUPERCELLS AS THE EARLY CONVECTIVE MODE. BY THE 00Z-04Z PERIOD...STRONGER LOW LEVEL MASS RESPONSE IN THE FORM OF A STRENGTHENING LLJ E AND SE OF THE KS/CO LOW OVER PARTS OF WRN KS AND WRN OK...WILL ACT TO ENLARGE HODOGRAPHS /200-500 M2/S2 EFFECTIVE SRH/ DURING THIS TIMEFRAME. AS A RESULT...SUPERCELL TORNADO POTENTIAL APPEARS HIGHEST DURING THE EVENING WITH PERHAPS A STRONG TORNADO OR TWO OCCURRING. UPSCALE GROWTH MAY EVENTUALLY OCCUR WITH ANY PERSISTENT OR REGENERATIVE CLUSTER OF SUPERCELLS WITH A LINGERING OVERNIGHT THREAT FOR A FEW TORNADOES AND DMGG WINDS.

http://www.spc.noaa.gov/products/outlook/day1otlk_1200.gif

http://www.spc.noaa.gov/products/outlook/day1probotlk_1200_torn.gif

SPC has gone with a Day 2 Moderate Risk...

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT SAT MAY 18 2013

VALID 191200Z - 201200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF ECNTRL OK...ERN KS AND WRN MO...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT PLAINS AND LOWER TO MID MO VALLEY...

...REGIONAL SEVERE WEATHER OUTBREAK POSSIBLE ACROSS PARTS OF THE SRN PLAINS...CNTRL PLAINS AND LOWER MO VALLEY...


...SRN AND CNTRL PLAINS/LOWER MO VALLEY...
A NEGATIVELY-TILTED UPPER-LEVEL TROUGH WILL MOVE EWD INTO THE SRN AND CNTRL PLAINS ON SUNDAY AS A MID-LEVEL JET MOVES EWD THROUGH THE CENTER OF THE TROUGH. AT THE SFC...A LOW IS FORECAST TO DEEPEN AND MOVE NEWD FROM CNTRL KS INTO ERN NEB AS A COLD FRONT ADVANCES SEWD ACROSS THE ECNTRL KS AND CNTRL OK. SFC DEWPOINTS TO THE EAST OF THE FRONT SHOULD BE IN THE MID TO UPPER 60S F WITH MODERATE TO STRONG DESTABILIZATION LIKELY ACROSS THE MODERATE RISK AREA BY MID TO LATE AFTERNOON. FORECAST SOUNDINGS AROUND MIDDAY SHOW A CAPPING INVERSION IN PLACE ACROSS MUCH OF THE WARM SECTOR. THE MODELS WEAKEN THE CAP BY 21Z ALLOWING FOR CONVECTIVE INITIATION ALONG AND AHEAD OF THE FRONT. STORMS SHOULD FIRST INITIATE IN NRN AND CNTRL KS...QUICKLY EXPANDING SWD INTO NRN AND CNTRL OK. AS STORM COVERAGE INCREASES DURING THE EARLY EVENING...A SEVERE PRODUCING MCS MAY ORGANIZE ACROSS ERN KS AND ECNTRL OK...MOVE ESEWD ACROSS THE MODERATE RISK AREA.


FORECAST SOUNDINGS BY 21Z SUNDAY AT TULSA...OKLAHOMA CITY AND KANSAS CITY SHOW STRONG INSTABILITY WITH MLCAPE VALUES OF 2500 TO 3500 J/KG. DEEP LAYER SHEAR IS FORECAST TO INCREASE DURING THE LATE AFTERNOON ACROSS THE MODERATE RISK AREA AS A MID-LEVEL JET MOVES INTO THE REGION FROM THE WEST. THIS COMBINED WITH 850 TO 500 MB LAPSE RATES EXCEEDING 8.0 C/KM SHOULD BE VERY FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. HAILSTONES OF GREATER THAN 2 INCHES IN DIAMETER WILL BE POSSIBLE WITH THE MORE INTENSE SUPERCELLS. IN ADDITION...A LOW-LEVEL JET IS FORECAST TO BECOME FOCUSED BY EARLY SUNDAY EVENING FROM SW MO SWWD INTO ECNTRL OK. SUPERCELLS ON THE WRN EDGE OF THE LOW-LEVEL JET WILL HAVE A CHANCE TO BECOME TORNADIC WITH A CLUSTER OF TORNADOES POSSIBLE ACROSS THE MODERATE RISK AREA. THE GREATEST CHANCE FOR STRONG TORNADOES SHOULD EXIST ACROSS ECNTRL OK AND SE KS WHERE 0-3 KM STORM RELATIVE HELICITIES ARE FORECAST TO REACH 400 M2/S2 IN THE 00Z TO 03Z TIMEFRAME. DUE TO THE STRONG DEEP LAYER SHEAR...CELLS SHOULD REMAIN DISCRETE DURING MUCH OF THE EVENT.
SUPERCELLS COULD ALSO PRODUCE SWATHS OF WIND DAMAGE. THE WIND DAMAGE THREAT COULD BECOME ENHANCED DURING THE EVENING IF A LINEAR MCS CAN ORGANIZE.

http://www.spc.noaa.gov/products/outlook/day2otlk_0600.gif

http://www.spc.noaa.gov/products/outlook/day2probotlk_0600_any.gif

NWS Norman's Forecast Discussion

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
216 AM CDT SAT MAY 18 2013


.DISCUSSION...
TODAY IS THE FIRST OF AT LEAST 3 DAYS OF EXPECTED SEVERE
THUNDERSTORMS. THE VERY MOISTURE-RICH AIRMASS WILL PERSIST AND
WAIT FOR THE APPROACH OF A DRYLINE TO WESTERN OKLAHOMA THIS
AFTERNOON. ALTHOUGH MID-LEVEL TEMPERATURES WILL BE WARM, SURFACE
TEMPERATURES ARE EXPECTED TO BE VERY HIGH ALONG THE DRYLINE. AT
LEAST IN A FEW AREAS, THE CAP SHOULD BE OVERCOME RESULTING IN
SEVERE THUNDERSTORMS LATER THIS AFTERNOON AND EVENING. THIS
EVENING A LOW-LEVEL JET WILL HELP INCREASE THE TORNADO THREAT IN
NORTHWEST OKLAHOMA. MID-LEVEL FLOW WILL ALSO INCREASE LATER TODAY
WHEN THE FIRST OF SEVERAL SHORT-WAVE TROUGHS ROTATE THROUGH THE
SYNOPTIC-SCALE TROUGH. MID-LEVEL FLOW AND RESULTING SHEAR IS
EXPECTED TO BE EVEN STRONGER SUNDAY. DRYLINE MIXING IS EXPECTED TO
OCCUR EARLIER AND A FRONT WILL BE PRESSING INTO NORTHWEST OKLAHOMA
FROM THE NORTH. ALTHOUGH MODELS DIFFER IN THE TIMING OF THE
FRONT, A TRIPLE POINT IN NORTHWEST OR WEST-CENTRAL OKLAHOMA SUNDAY
AFTERNOON AND MOVE EAST WITH THE DRYLINE. BY THE TIME OF
THUNDERSTORM RE-INITIATION, THE MAIN SEVERE THREAT IS EXPECTED TO
MOSTLY EXCLUDE THE WESTERN QUARTER OF OKLAHOMA, BUT CENTRAL AND
NORTH-CENTRAL OKLAHOMA WILL BE IN AREAS OF VERY STRONG INSTABILITY
AND HIGH SHEAR. TORNADOES AND EXTREMELY LARGE HAIL ARE EXPECTED TO
OCCUR. A DEVELOPING LOW-LEVEL JET ACROSS CENTRAL OKLAHOMA IN THE
EVENING WILL INCREASE THE TORNADO THREAT. THE FRONT IS EXPECTED
TO SLOW AND STILL BE DRAPED NORTHWEST TO SOUTHEAST ACROSS OKLAHOMA
MONDAY, BUT THE LOCATION IS UNCERTAIN. THIS WILL BE THE FOCUS FOR
MORE THUNDERSTORMS MONDAY WHEN SHEAR AND INSTABILITY WILL BE
SUFFICIENT FOR ANOTHER DAY OF SEVERE WEATHER. EVEN A GOOD CHANCE
REMAINS IN SOUTHEAST OKLAHOMA ON TUESDAY. LATER IN THE WEEK A
CHANCE FOR RAIN REMAINS WITH EASTERLY FLOW IN THE MODERATELY MOIST
AIRMASS

30% Hatched Slight Risk for Monday

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0231 AM CDT SAT MAY 18 2013

VALID 201200Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...CNTRL PLAINS...MID MS VALLEY...UPPER MS VALLEY AND GREAT
LAKES REGION...

...REGIONAL SEVERE WEATHER EPISODE POSSIBLE ACROSS PARTS OF THE SRN
AND CNTRL PLAINS INTO THE OZARKS MONDAY AFTERNOON AND EVENING...

...SRN AND CNTRL PLAINS/OZARK PLATEAU...
AN UPPER-LEVEL LOW WILL REMAIN IN PLACE ACROSS THE NRN AND CNTRL
PLAINS ON MONDAY WITH SOUTHWEST FLOW LOCATED FROM THE SRN PLAINS
INTO THE MID MS VALLEY. AT THE SFC...A LOW IS FORECAST TO MOVE NEWD
ACROSS THE SRN PLAINS WITH DEWPOINTS SOUTH AND EAST OF THE LOW IN
THE MID TO UPPER 60S F. A CAPPING INVERSION IN PLACE FOR MUCH OF THE
DAY...SHOULD WEAKEN BY LATE AFTERNOON ALLOWING FOR ROBUST CONVECTIVE
INITIATION. MODEL FORECASTS DEVELOP SEVERAL CLUSTERS OF
THUNDERSTORMS LATE MONDAY AFTERNOON FROM THE SFC LOW NEAR THE RED
RIVER NEWD INTO CNTRL AND ERN OK. THE MODELS APPEAR TO ORGANIZE AN
MCS ACROSS THE SRN PLAINS AND MOVE THIS CONVECTIVE SYSTEM NEWD INTO
THE OZARKS DURING THE EVENING.

FORECAST SOUNDINGS IN SRN OK AND NEAR THE RED RIVER IN NORTH TX AT
00Z/TUE SHOW IMPRESSIVE THERMODYNAMIC AND SHEAR PROFILES WITH MLCAPE
VALUES OF 2500 TO 3500 J/KG AND 0-6 KM SHEAR VALUES OF 45 TO 55 KT.
THIS ENVIRONMENT SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL.
HAILSTONES OF GREATER THAN 2 INCHES IN DIAMETER WILL BE POSSIBLE
WITH THE MORE DOMINANT SUPERCELLS. IN ADDITION...LOW-LEVEL
HODOGRAPHS ALSO LOOK IMPRESSIVE WITH 0-3 KM STORM RELATIVE
HELICITIES IN THE 400 TO 50O M2/S2 RANGE BY EARLY MONDAY EVENING.
THIS SUGGESTS TORNADIC SUPERCELLS WILL BE POSSIBLE WITH A POTENTIAL
FOR STRONG TORNADOES. IF MESOSCALE CONDITIONS COME TOGETHER AS THE
MODELS SUGGEST...THEN A CLUSTER OF TORNADOES COULD OCCUR ACROSS
PARTS OF THE SRN PLAINS LATE MONDAY AFTERNOON INTO THE EVENING. WIND
DAMAGE WILL ALSO BE POSSIBLE WITH SUPERCELLS AND BOWING
LINE-SEGMENTS. THE MAIN CONCERN ABOUT FORECASTING A SIGNIFICANT
EVENT THIS FAR OUT...IS THAT MULTIPLE DAYS OF THUNDERSTORMS BETWEEN
NOW AND MONDAY WILL LIKELY ALTER THE OUTCOME AND THAT THE SCENARIO
WILL BE DIFFERENT THAN WHAT IS CURRENTLY PRESENTED BY THE MODELS.


http://www.spc.noaa.gov/products/outlook/day3prob_0730.gif

Appreciate the dedication to task, Venture, but 2:43AM?? If you're just a single human being and not a conglomeration of OUN meteorologists or a weather bot, what are you drinking to keep you up during these weather binges, because I gotta get some before Monday.

IF MESOSCALE CONDITIONS COME TOGETHER AS THE
MODELS SUGGEST...THEN A CLUSTER OF TORNADOES COULD OCCUR ACROSS
PARTS OF THE SRN PLAINS LATE MONDAY AFTERNOON INTO THE EVENING.

Outstanding...youngest daughter gradjiates from high school at 6:30PM Monday...in a massive, free-span roof churchey type building.

Appreciate the dedication to task, Venture, but 2:43AM?? If you're just a single human being and not a conglomeration of OUN meteorologists or a weather bot, what are you drinking to keep you up during these weather binges, because I gotta get some before Monday.

Trust me when its over I'll be sleeping for days. The other half thinks I'm insane. :)

Moderate risk continues for much of Western OK north of I-40 and slight risk for the rest of the western half of the state - includes the metro.

This morning mix of sun and clouds with some isolated showers/storms over Western and Central sections. Don't expect much from this, but everything should dry out in a few hours and start heating up. HRRR showing storm initiation beginning out west around 4PM. Line of supercells would be in the Metro around around 7 to 8PM tonight.

http://rapidrefresh.noaa.gov/HRRR/from_jet/hrrr_jet/2013051811/t5/cref_t5sfc_f13.png

Anyone else getting real tired of Mike Morgan mentioning Reed Timmer and the Dominator every other sentence?

No, and that's only because I simply don't watch him/KFOR for all the hysterics.

Chat room today: Live Chat | Weather Spotlight (http://www.weatherspotlight.com/?page_id=40)

Planning on being in an out most of the day and then in there more full time around 4PM when things get cranking.

Wow. So much of what happens tomorrow is dependent upon today, then Monday is dependent upon Sunday, so many variables at play, seems like the smartest thing anyone could do at this point is just stay aware of conditions and know things could fire up and get serious any afternoon/evening over the next few days. Really volatile setup, and I don't envy the folks like Venture who have to assemble it into some cogent forecast!!!

Trust me when its over I'll be sleeping for days. The other half thinks I'm insane. :)
Lol. I think she needs to start her own opinion thread on here. I bet it'd be good stuff!!

So what day does the tornado risk look to be greatest for the metro? Some news stations are saying Sunday but now KOCO is saying it will be Monday.

So what day does the tornado risk look to be greatest for the metro? Some news stations are saying Sunday but now KOCO is saying it will be Monday.

All depends on previous day's activity. Tomorrow looks higher than today, but beyond that it is a crap shoot to call.

My current chase target for today is SW OK as to avoid the chaser circus that is sure to ensue in NW OK and SW KS. Will post more in a bit.

My current chase target for today is SW OK as to avoid the chaser circus that is sure to ensue in NW OK and SW KS. Will post more in a bit.

I like that target, but I always preferred SW OK to any other place to chase. :)

Didn't post this earlier...here is the actual upper air sounding. We can see why some storms/showers are just going up with the little bit of sun this morning.

http://climate.cod.edu/data/raob/KOUN/skewt/KOUN.skewt.20130518.12.gif

Newest HRRR for 4PM today...

http://rapidrefresh.noaa.gov/HRRR/from_jet/hrrr_jet/2013051813/t5/cref_t5sfc_f08.png

Looks like things are starting to clear out pretty quickly now out west and even over parts of Central OK. Now begins the baking process to get things even more charged up than what they already are.

http://www.mesonet.org/data/public/noaa/sat/maps/realtime/latest.goes_east.visible.png

No, and that's only because I simply don't watch him/KFOR for all the hysterics.


I'll watch KFOR when they put Emily Sutton in the field in a comparable chase contraption and then only if she calls it "Dominatrix 4"...

14Z HRRR run has me a bit more concerned for Central OK today. Storm relative helicity values in the first 0-1km of the storm is showing values up over 300-400 m^2/s^2. This is pretty darn favorable for strongly rotating storms. LCLs are also shown to start dropping to less than 750m down I-44.

If this can be realized, we should probably see the SPC extend the moderate risk further south and east in one of the following updates.

Forecast sounding for 7PM tonight...

http://beta.wxcaster.com/skewts/RUC-test/009/SKT_RUC__KOUN.png