General Weather Discussion - April 2014

[venture]

16Z HRRR pops storms south of Childress by 6PM...



Move into OK (including new development)...by 8PM

[SoonerDave]

Definitely a lot of pessimistic views on the chances for this afternoon and evening..... We are seeing plenty of CU starting to go up from Canadian County SW along/northwest of I-44 into North Texas. Convective temps today are in the 90s, so if any location can make a run at that...then we have a change to bust the cap.

.

When I went out to get the mail a few moments ago, I saw that same region of cumulus to my NW (almost certainly in the Canadian County area) sure looking like it was at least trying to get organized...

[venture]

When I went out to get the mail a few moments ago, I saw that same region of cumulus to my NW (almost certainly in the Canadian County area) sure looking like it was at least trying to get organized...

Yeah it is just going to take one to bust through to get the show going. We'll probably see a few attempts early on of cells trying to go up and collapsing, but eventually one will probably make it. Where exactly is the question.

[SoonerDave]

Yeah it is just going to take one to bust through to get the show going. We'll probably see a few attempts early on of cells trying to go up and collapsing, but eventually one will probably make it. Where exactly is the question.

Okay, Venture, this question borders on the impossible, but since things have migrated toward an isolated risk more than a broad risk, what kind of implications do you think this has for the Memorial run in the morning? The big race starts at 6:30, the 5K at 6:40, but there will be TONS of people down there as early as 5:00-5:30 for pre-race events/ceremonies and such. Or does it just depend too much on dryline migration?

[venture]

Okay, Venture, this question borders on the impossible, but since things have migrated toward an isolated risk more than a broad risk, what kind of implications do you think this has for the Memorial run in the morning? The big race starts at 6:30, the 5K at 6:40, but there will be TONS of people down there as early as 5:00-5:30 for pre-race events/ceremonies and such. Or does it just depend too much on dryline migration?

I think a lot comes into play if we see the dryline light up over night as the main storm system kicks through.

[soonerguru]

I think a lot comes into play if we see the dryline light up over night as the main storm system kicks through.

What are the implications either way? If we don't see it light up over night does that increase or decrease the odds of tomorrow's activity being more intense?

[SoonerDave]

I went back through a few posts thinking you had mentioned it earlier, but I couldn't find it - where is the dryline now?

[SoonerDave]

What are the implications either way? If we don't see it light up over night does that increase or decrease the odds of tomorrow's activity being more intense?

You've got a secondary set up for tomorrow afternoon that's just naturally part of the afternoon heating cycle ahead of the advancing front, but with higher relative humidity and dewpoints, so that risk for eastern OK exists almost regardless of what happens overnight..except to the extent any overnight storms beat up the atmosphere so much that it has to have time to recover before the next round can start. If even the overnight storms are isolated or don't happen, still seems to me the risk for E Oklahoma tomorrow is just as high if not higher than W OK today. Judging by the language the SPC is using on some of their outlooks, I think they're more confident/concerned about the potential going into the SE US over the next few days.

As I recall, the Birmingham tornado from a few years ago (2011 if memory serves) was a relatively early season event, because I remember driving through there later that summer right through some of the worst damage, and it was eerily reminiscent of May 3...the sobering part was that the particular area was not a particularly thriving area economically to begin with, and it was hard to see how that area was going to rebuild - or that, at a minimum, it was going to take a long, long time. There were areas of destruction that hadn't even been close to cleared, or even touched.....but I digress...sorry..

[soonerguru]

You've got a secondary set up for tomorrow afternoon that's just naturally part of the afternoon heating cycle ahead of the advancing front, but with higher relative humidity and dewpoints, so that risk for eastern OK exists almost regardless of what happens overnight..except to the extent any overnight storms beat up the atmosphere so much that it has to have time to recover before the next round can start. If even the overnight storms are isolated or don't happen, still seems to me the risk for E Oklahoma tomorrow is just as high if not higher than W OK today. Judging by the language the SPC is using on some of their outlooks, I think they're more confident/concerned about the potential going into the SE US over the next few days.

As I recall, the Birmingham tornado from a few years ago (2011 if memory serves) was a relatively early season event, because I remember driving through there later that summer right through some of the worst damage, and it was eerily reminiscent of May 3...the sobering part was that the particular area was not a particularly thriving area economically to begin with, and it was hard to see how that area was going to rebuild - or that, at a minimum, it was going to take a long, long time. There were areas of destruction that hadn't even been close to cleared, or even touched.....but I digress...sorry..

Don't ever apologize for showing your humanity to people who are suffering.

[PennyQuilts]

All I can say is that east of Mustang, it feels like storm rising.

[soonerguru]

It's gotten overcast and very humid in OKC.

[LocoAko]

Moisture has been mixing out in SW OK for a while now. I'll be headed out shortly to chase, but only because I have a friend from out of town who I promised I'd chase with no matter what. May hike in the Wichitas while we wait. Either way, storms look isolated at best -- but as venture said, it only takes one doozy to ruin someone's day. From a photography standpoint one isolated supercell may be best. I'd put the odds of a total cap bust prior to 9PM at 70% right now.

[jn1780]

Onward to the first week or two of May! lol

[soonerguru]

How is Atlanta area looking Wed-Thursday?

[SoonerDave]

Mesoscale discussion released a few minutes ago by the SPC.... weather watch termed "unlikely" although, as Venture has pointed out, there's still a chance for some stormage:

Storm Prediction Center Mesoscale Discussion 409

[venture]

I had just tweeted out that I think the exhaust from all the chasers in SW OK right now should help them reach the convective temp and bust the cap...apparently HRRR agrees.

Image for 6PM...

[Anonymous.]

Looks like the first legit towers trying to break through in NW TX right now.

[venture]

Cell near Roby looks the best right now.

[Jon27]

It was sprinkling in Yukon. I have no idea what the significance of that is to anything.

[venture]

Two panel image of the two cells trying to go up. Base Reflectivity on left, Echo Tops on the right which can help show elevated returns. Tracks are for one hour.

[venture]

MESOSCALE DISCUSSION 0410
NWS STORM PREDICTION CENTER NORMAN OK
0622 PM CDT SAT APR 26 2014

AREAS AFFECTED...PORTIONS OF WEST CENTRAL AND WRN NORTH TX INTO SWRN
OK

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 262322Z - 270045Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...PORTIONS OF WEST CENTRAL AND WRN NORTH TX INTO SWRN OK ARE
BEING MONITORED FOR POTENTIAL WATCH ISSUANCE. A TSTM HAD DEVELOPED
IN FISHER COUNTY AND ADDITIONAL STORMS WILL BE POSSIBLE WITHIN A N-S
ORIENTED CORRIDOR...GENERALLY 35-45 MILES EITHER SIDE OF A LINE FROM
35 S ABI TO 20 N LTS....WITH LARGE HAIL AND DAMAGING WINDS BEING THE
INITIAL PRIMARY THREATS.

DISCUSSION...TRENDS IN VISIBLE SATELLITE/RADAR IMAGERY CONTINUED TO
SHOW TWO DRY LINES OVER THE WRN PORTION OF THE SRN PLAINS. ONE
EXTENDED FROM ALONG THE WRN OK/TX PANHANDLE BORDER SWWD TO 25 N MAF
AND THEN SWD TO 25 WSW OF SANDERSON TX. A SECOND DRY LINE WAS
LOCATED TO THE EAST OF THE FIRST ONE AND WAS RETREATING SLOWLY WWD
PER TRENDS IN RADAR IMAGERY INVOF OF ABI NWD INTO FAR SWRN OK. THIS
SECOND DRY LINE APPEARS TO BE DELINEATING HIGHER MOISTURE RETURN
WITH SURFACE DEWPOINTS IN THE MID-UPPER 50S TO ITS EAST COUPLED WITH
SURFACE TEMPERATURES INTO THE LOWER-MID 90S ALONG THIS DRY LINE
FEATURE. THESE OBSERVED THERMODYNAMICS HAVE AIDED IN WEAKENING OF
SURFACE-BASED INHIBITION THAT WAS PRESENT EARLIER.

TRENDS IN LOW-LEVEL WINDS DURING THE MID-LATE AFTERNOON FROM EXTREME
SWRN OK TO SJT HAVE BACKED TO SLY...WHILE WINDS AT THE SAME LEVEL
FROM AMA-MAF WERE WSWLY INDICATING A ZONE OF LOW-LEVEL CONFLUENCE
PRIMARILY ALONG THE SECOND DRY LINE. IT IS ALONG THIS BOUNDARY WITH
A WEAKENED CAP THAT SATELLITE AND RADAR IMAGERY SHOWED TOWERING CU
AND A COUPLE CB/S. A COUPLE OF LIGHTNING STRIKES WERE DETECTED IN
FISHER COUNTY TX AROUND 2245Z. THE INCREASE IN LOW-LEVEL
CONVERGENCE APPEARS TO BE IN RESPONSE TO AN APPARENT MIDLEVEL
IMPULSE OR JET STREAK TRACKING NEWD THROUGH WEST CENTRAL TX AT THIS
TIME. ASCENT WITH THIS FEATURE IS ALSO LIKELY AIDING IN THE
INCREASE IN CONVECTIVE DEVELOPMENT...MAINLY ALONG THE DRY LINE
WITHIN THE DISCUSSION AREA. FURTHER W/NWWD MOISTURE RETURN INTO
THIS BOUNDARY INTO THE EARLY EVENING SHOULD BOOST INSTABILITY FOR
MORE ROBUST UPDRAFT POTENTIAL. EFFECTIVE BULK SHEAR OF 30-35 KT
ORIENTED ACROSS THE DRY LINE WILL SUPPORT DISCRETE STORMS...WITH A
STEEP LAPSE RATE ENVIRONMENT FAVORING A THREAT FOR LARGE HAIL.
MEANWHILE...LARGE SURFACE TEMP-DEWPOINT SPREADS /35-40 DEGREES/ TEND
TO RESULT IN LP SUPERCELLS ENHANCING A THREAT FOR DAMAGING WIND
GUSTS. IF TSTM COVERAGE AND/OR INTENSITY INCREASES
SUFFICIENTLY...THEN A WATCH MAY BE NEEDED.

..PETERS/HART.. 04/26/2014

[venture]

1 Hour tracks on all storms attempting to increase and get established.

[Anonymous.]

If these can get going and sustain into the deeper moisture, we could see some big hail.

[venture]

Here is the cell in Hardeman Co, TX just over the border...

[venture]

Storm in NE Stonewall County, TX appears to have busted the cap. Hail being indicated now.