May '10 Weather Discussion

[venture]

Four days in and I totally forgot to get the new thread going. Yes, it has been that slow. LOL

Have no fear! Or well, I guess it depends on your point of view. Models are indicating a change starting next week, but even then it isn't a long duration event. Rough estimate looks like out of the next 17 days, maybe 3-4 will be severe weather days. Extremely quiet for the peak of the season. Of course, it appears the season has been held back a bit by El Nino so we might actually have our busy season more into June/July this year.

Regardless, next potential day appears to be May 10th.

Discussion here: AnvilCrawlers.com - View topic - 5/10/2010 - W OK, TX Panhandle

The Live Chat for May Weather is here: May AC Discussion | Liveblog live blogging

And of course I'm continuing to expand the weather resources available at: AnvilCrawlers.com - Weather Forum and Discussion for Oklahoma

[Thunder]

Yay! Venture, how much will all of this cost us?

[BrettL]

Monday is looking to be a big day weather-wise. This mornings models show a possible significant event for the western half of Oklahoma.

[venture]

Just going to go off of the 12Z models for these. Will make a couple posts as I get them done on AC.

Sunday

Discussion: AnvilCrawlers.com - View topic - 05/09/2010 - Southern Oklahoma

[venture]

Monday's Outlook


Discussion: AnvilCrawlers.com - View topic - 5/10/2010 - W OK, TX Panhandle

[Thunder]

It is nice that mother nature is allowing us a rain-free day on Sunday.

[venture]

It is nice that mother nature is allowing us a rain-free day on Sunday.

I wouldn't go that far. :-P My outlook is just based on convective/storm development. There is probably going to be plenty of elevated showers/storms across the state.

[blangtang]

Crazy Mike says we're all gonna die on Monday! Get a fraidy hole soon!

[Ezrablum]

I love being able to sleep with the windows open.

[westsidesooner]

Monday...especially Monday evening is starting to look pretty impressive....I keep wondering whats going to change in the next few days to mess it up. The main thing I'm worried about at this time is that it may be a late show with the strong cap in place. Hopefully things will kick up a little earlier....nothing worse, or more dangerous than a nighttime event.

[BrettL]

Monday...especially Monday evening is starting to look pretty impressive....I keep wondering whats going to change in the next few days to mess it up. The main thing I'm worried about at this time is that it may be a late show with the strong cap in place. Hopefully things will kick up a little earlier....nothing worse, or more dangerous than a nighttime event.

Yeah the cap looks pretty stout but I think there will be enough to break it by 5 or 6 PM. We're heading out Monday for sure. If this forecast holds it could be quite an outbreak. I do like the expanded risk area so the chaser convergence won't be so bad, especially with Vortex 2 out now. Not like April 22nd when we had 500 chasers on 1 storm. Not safe at all....

[venture]

Will be updating my outlook here in a few. Here is the update SPC outlet with extremely strong wording...for a Day 5 forecast.



DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0322 AM CDT THU MAY 06 2010

VALID 091200Z - 141200Z

...DISCUSSION...

06/00Z ECMWF...GFS AND MEDIUM-RANGE ENSEMBLE GUIDANCE ARE IN GENERALLY GOOD AGREEMENT IN THE EVOLUTION OF THE LARGE-SCALE PATTERN THROUGH THE EXTENDED FORECAST PERIOD. ON DAY 4 /SUN MAY 9TH/...THE NWD RETURN OF A MOIST BOUNDARY LAYER BENEATH THE ERN EDGE OF AN EML DEVELOPING OVER THE WRN STATES WILL CONTRIBUTE TO A MODERATELY UNSTABLE AIR MASS OVER WRN TX. THERE IS SOME INDICATION THAT A WEAK...LOW AMPLITUDE PERTURBATION MAY PROGRESS EWD INTO THE SRN HIGH PLAINS BY LATE DAY...POSSIBLY SUPPORTING ISOLATED STORM FORMATION ALONG THE DRY LINE...OR PERHAPS A RETREATING WARM FRONT. VERTICAL SHEAR WILL BE SUFFICIENT FOR ORGANIZED STORMS INCLUDING SUPERCELLS WITH THE THREATS FOR HAIL AND PERHAPS TORNADOES. DUE TO UNCERTAINTIES IN STORM INITIATION AND POTENTIAL COVERAGE...NO SEVERE WEATHER AREA WILL BE INCLUDED IN THIS FORECAST.

ON DAY 5 /MON MAY 10TH/...MODEL GUIDANCE REMAINS CONSISTENT IN THE NEWD PROGRESSION OF AN INTENSE...NEGATIVELY-TILTED MIDLEVEL TROUGH INTO THE CNTRL PLAINS. AN ASSOCIATED...RAPIDLY DEEPENING SURFACE LOW OVER THE CNTRL HIGH PLAINS WILL DRAW A MOIST AIR MASS NWD...SETTING THE STAGE FOR A POTENTIAL OUTBREAK OF SUPERCELLS CAPABLE OF VERY LARGE HAIL AND SIGNIFICANT TORNADOES.

ON DAY 6 /TUE MAY 11TH/...THE SYNOPTIC SYSTEM IS FORECAST TO DE-AMPLIFY/FILL AS IS PROGRESSES NEWD INTO THE UPPER GREAT LAKES. SEVERE STORMS WILL REMAIN POSSIBLE ALONG THE COLD FRONT FROM THE UPPER MIDWEST INTO OZARK PLATEAU. HOWEVER...GIVEN THE EXPECTED POOR LAPSE RATES...WEAKENING SYSTEM AND POTENTIAL FOR ONGOING/WIDESPREAD STORMS...THE POTENTIAL FOR A MORE WIDESPREAD SEVERE WEATHER EVENT REMAINS IN QUESTION.

ON DAY 7 /WED MAY 12TH/...THE ECMWF AND GFS ARE IN RELATIVELY GOOD AGREEMENT IN THE SLOW EWD PROGRESSION OF A LARGE-SCALE TROUGH OVER THE WRN STATES. HOWEVER...DIFFERENCES DO EXIST IN THE LOCATION OF NE-SW ORIENTED BAROCLINIC ZONE WHICH WILL STRETCH FROM WEAKENING LOW PRESSURE OVER THE GREAT LAKES REGION INTO THE SRN PLAINS. THIS FRONTAL LOCATION BECOMES EVEN MORE PROBLEMATIC WHEN FACTORING IN THE POSSIBILITY THAT EPISODIC TSTM ACTIVITY FOR THE PREVIOUS TWO DAYS COULD POTENTIALLY DISPLACE THE EFFECTIVE FRONT EVEN FARTHER S. WHILE THE ENVIRONMENT ALONG AND TO THE S OF THIS BOUNDARY WILL BE SUPPORTIVE OF SEVERE STORMS...UNCERTAINTY IN ITS LOCATION PRECLUDES THE ISSUANCE OF AN ADDITIONAL SEVERE WEATHER AREA.

[Thunder]

David, you know what is so sad? Monday was recently my day off before it was switched with Wednesday. >_<

[venture]

Updated Monday's outlook. Felt there is enough confidence to put in a moderate risk in my outlook. Cap will be very stout, so it could throw a snag in things. However, convective temp is suppose to be in the low 90s - and surface temps are expected to get there - so it should be overcome in a few areas.

I will say, conditions will be extremely favorable for strong tornadoes should a storm develop. The other major factor, storm motions are expected to be up around 40-45 mph. These things could be flying and very dangerous to not only chase, but for those in the path. Advanced warning time will be lower than normal, so everyone will need to be on their toes.

[westsidesooner]

Back when I was a member of stormtrak......before they kicked all the "lurkers" out, they use to have a "pick your sweet spot" contest. Picking as closely as you could days in advance of an outbreak where you thought a tornado was most likely to touchdown by placing your marker on a map. It would be fun to have something like that on AnvilCrawles. hint hint.

Right now I'm saying between Canton and Enid. Myabe hang out along hwy 58. I'm sure I'll change my mond between now and then as the situation (boundaries, timing) becomes more clear. Anyone else have a guess???

[venture]

Risk area updated some, see graphic earlier in this thread.

Discussion: AnvilCrawlers.com - View topic - 5/10/2010 - W OK, TX Panhandle

Westside...I went ahead and outlined two areas I would focus on right now, I'll try to nail down my target by Sunday evening. However, these are my best guesses. One thing I noticed in the 00Z run is that the cap strength came down a bit, but it is still pretty stout. There is also a noticeable weakness in SW Oklahoma by Monday evening, which could be exploited pretty easily.

Either way, this day is looking like one of the bigger potential outbreak days we've had in awhile. Which of course means I just jinxed it. : ) Instability has come up a bit since the runs earlier on Thursday. It also seems the dryline is moving a tad faster on GFS, but not too far. Everything is really there to where the potential for high end severe weather (strong/violent tornadoes) is bordering on the scary side. Especially with the risk of fast moving, night time storms. GFS maintains instability that would support severe weather through around Midnight.

I would not be shocked to see a Day 3 moderate risk from SPC when Saturday roles around. At the very least, they'll go with a high end slight risk with a hatched area.

[scootweather]

With the person that I should be chasing with on Monday our target area is probably going to be somewhere on the OK/KS border at the triple point. Of course we are STILL WAY FAR OUT to predict anything. I won't start looking at models until this time tomorrow.

[venture]

With the person that I should be chasing with on Monday our target area is probably going to be somewhere on the OK/KS border at the triple point. Of course we are STILL WAY FAR OUT to predict anything. I won't start looking at models until this time tomorrow.

That's probably the safer bet out of the two. The southwest target has the potential to be the later show. Of course like you said, we still got a few days and the only thing that matters is what is going on Monday morning - at least when it comes to forecasting where to go.

Going out further, added a few more days to the long term outlook. Again, these change pretty wildly depending on how grumpy the models are that day - but they are there as a guide.

So the extended outlook...or risk days are:

May 10th - We have that covered already.
May 11th - Slight risk, mainly SE Oklahoma along the front.
May 12th & 13th - Front will slowly move back to the NW, so a risk of maybe some severe weather near it it...mostly to the east of I-35.
May 16th - Looks like the potential for another strong storm system with a weaker cap.
May 17th through 20th - Potential for some severe weather, somewhere in the state...each day. Will get more in focus as we get closer.

Long story short. Most attention is going to be on this coming Monday so the longer term forecasts of mine won't get a whole lot of attention right now.

[OUman]

Forecast hodographs paint an ominous picture for Monday evening, at least the way things looks right now. It will need to be watched closely for sure.

[venture]

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0227 AM CDT SAT MAY 08 2010

VALID 101200Z - 111200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CNTRL/SRN PLAINS TO THE MID-MS VLY...

...SYNOPSIS...
THE MID-LVL WAVE LOCATED OVER THE GRT BASIN LATE IN THE WEEKEND WILL EJECT ACROSS THE CNTRL/SRN PLAINS AS A NEGATIVE-TILT TROUGH ON MONDAY AS THE NEXT IMPULSE DROPS SEWD TO THE PAC NW. AT THE SFC...A LEE LOW WILL INTENSIFY OVER ERN CO THEN MOVE ACROSS NRN KS BY MONDAY EVENING THEN TO SRN IA BY 12Z TUESDAY. A DRYLINE WILL MIX EWD TO THE S OF THE LOW...REACHING WRN KS AND THE TX/OK BORDER AREA BY EARLY AFTN MONDAY...THEN INTO CNTRL KS AND WRN OK BY EVENING. TO THE E...A WRMFNT WILL CONTINUE TO DEVELOP NWD INTO THE MID-MS VLY.

...CNTRL/SRN PLAINS TO THE MID-MS VLY...
MONDAY STILL HAS THE POTENTIAL TO BE AN ACTIVE WEATHER DAY WITH STRONG TORNADOES AND VERY LARGE HAIL POSSIBLE...PARTICULARLY OVER CNTRL/SCNTRL KS AND EXTREME NWRN/NCNTRL OK.

BANDS/CLUSTERS OF ELEVATED TSTMS ARE EXPECTED TO BE ONGOING EARLY MONDAY ACROSS PORTIONS OF ERN KS/OK OWING TO A ROBUST WAA REGIME WITHIN A BROAD 45-50 KT SSWLY LLJ. THIS ACTIVITY MAY PROVE PROBLEMATIC FOR A NWD EXPANSION OF THE WARM SECTOR MONDAY AFTN AND THIS UNCERTAINTY WAS THE PRIMARY REASON FOR NOT UPGRADING TO A MDT RISK.

CONFIDENCE REMAINS SUFFICIENTLY HIGH...HOWEVER...IN THE RETURN OF MID/UPR 60S BOUNDARY LAYER DEW POINTS E OF THE DRYLINE/TRIPLE POINT INTO AT LEAST SWRN KS BY AFTN. DRYLINE CIRCULATION WILL DEEPEN WITH APPROACH OF THE UPR TROUGH BY MID-AFTN AND STRONG HEATING WILL ERODE CINH FOR TSTM INITIATION...MOSTLY LIKELY IN WRN KS. FARTHER S...CINH WILL BE STRONGER AND LARGE SCALE FORCING COMPARATIVELY WEAKER ACROSS WRN OK. BUT...ISOLD STORM DEVELOPMENT CANNOT BE RULED OUT AS FAR S AS WRN OK/RED RIVER.

EFFECTIVE SHEAR IN EXCESS OF 55 KTS AND THE ORIENTATION OF VECTORS PERPENDICULAR TO THE DRYLINE WILL STRONGLY SUPPORT SUPERCELLS. FCST HODOGRAPHS EXHIBIT STRONGLY VEERING LOW-LEVEL WINDS WITH THE COMPLETE VERTICAL PROFILE SIGNATURES INDICATIVE OF HISTORIC STRONG TORNADIC CASES. VERY LARGE HAIL WILL ALSO BE POSSIBLE.

AS MENTIONED BEFORE...IT IS UNCLEAR HOW FAR N AND E THE QUALITY WARM SECTOR WILL EXPAND. THE MAXIMUM TORNADO THREAT MAY REALISTICALLY BE IN NARROW ZONE ACROSS SCNTRL/CNTRL KS INTO NCNTRL OK BEFORE STORMS MOVE TOWARD A MORE STABLE LOW-LEVEL ENVIRONMENT. LATER OUTLOOKS CAN ADDRESS THIS UNCERTAINTY.

OTHERWISE...STORMS WILL LIKELY DEVELOP INTO ONE OR MORE MCS/S AND DEVELOP/MOVE ENE TOWARD THE MID-MS VLY OVERNIGHT WITH LARGE HAIL THE PRIMARY THREAT.

[blangtang]

so liklihood is north of Okc metro?

[venture]

so liklihood is north of Okc metro?

They are thinking denser coverage will be further north, but it only takes one or two supercells to break through the cap along the dryline to make an outbreak.

[Thunder]

SPC isn't picking up on the 2nd L forming to our southwest?

[oknacreous]

Most likely area for tornadoes Monday, some strong/violent, appears to be in the area inside the line from Chickasha up to Enid, Hutchinson KS, Emporia KS, down to Tulsa, Shawnee, and back to Chickasha. That includes OKC metro, Stillwater, Ponca City, Bartlesville and Wichita KS.

Slight chance of a lone supercell or two on Tuesday afternoon down around Wichita Falls/Lawton, if the cap can break (about a 30% chance). Tornadoes very possible if that can happen.

A few scattered supercells and tornadoes possible Wednesday afternoon in the Ponca City/Enid to Lawton/Wichita falls corridor before a severe squall line Wednesday night.

[venture]

Updated my outlook graphic...see post: http://www.okctalk.com/current-event...tml#post324669

18Z GFS is just coming in now, so it may need some tweaking. Seeing a general move towards agreement between NAM and GFS. This outlook right now is a best estimate going in between the two models. Risk areas are probably lined up about right. Still a lot of key questions coming into play. The one is the cap. Can it break? Further north in the MDT risk area CINH is projected to be lower and so the cap will likely be able to break there first. Farther south in the MDT risk area closer to I-40 and points south, it depends on the model.

GFS is extremely stout and also pushes a convective temp into the upper 90s, which won't be realized. NAM pulls it back with a much weaker cap and a convection temp in the low 80s - totally doable.

So going to have the play the middle for a bit longer.