General Weather Discussion - April 2014

[jn1780]

They must have a pretty big weather department budget. I'm sure upper management is more upset about the slow season than the chasers.

"I don't care if there isn't going to be a widespread outbreak tomorrow. Get those souped up trucks out there NOW!!" lol

[PennyQuilts]

Jn1780, I guess I'm not the only one who looked at that fleet and started thinking about how much all that cost - and how they pay for it.

[venture]

No major changes with the 00Z NAM except maybe just a smidge slower. Not a lot of widespread coverage but still storms forming in SW OK moving up I-44.

[John1744]

Michael Armstrong's take.

https://www.facebook.com/michael.arm...340620?fref=nf

Okay, I'm officially concerned about tomorrow night. This is simply meant to encourage you to pay close attention to the weather and have a plan if you live in central or SW OK on Saturday night, particularly between 6pm and midnight. ***Please share this update with your friends***

Here is the deal:

The latest data has been trending toward higher quality moisture return right at the time storms develop Saturday evening. This will offset the sun going down and create an atmosphere that is both unstable and weakly capped. As a result, I expect widespread storms including some supercells to develop in the general vicinity of Altus and Lawton between 5 and 7 pm, then move northeastward toward central OK between 8 and 10pm. Other storms could develop northward all the way to the OK-KS border as well during this time.

Meanwhile, low-level shear will be increasing dramatically during this time period. The current projections indicate strong tornadoes will be possible even after dark for a few hours.
I recognize that this is not what many of you want to hear, especially coming from me. I actually debated about even writing this as a result. Clearly I am no fortune teller, I am not God, and I can only give you an opinion based on my prior experience and training. I have no hidden agenda or "dog in the hunt", but I think it's important if I recognize a potentially dangerous situation to communicate it.

Finally, this is not locked in. Changes remain possible. The best thing to do is to have a plan A, and then have a plan B in case plan A doesn't work. The people who panic are the people who do not adequately prepare. I'll update again tomorrow. - Michael

[venture]

New Day 1

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1257 AM CDT SAT APR 26 2014

VALID 261200Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN THROUGH CNTRL
PLAINS AREAS...

...SUMMARY...
ISOLATED TO SCATTERED SEVERE STORMS ARE EXPECTED TO DEVELOP ACROSS
THE SOUTHERN AND CENTRAL PLAINS LATE SATURDAY AFTERNOON AND CONTINUE
INTO THE OVERNIGHT. THE PRIMARY THREATS WILL BE VERY LARGE HAIL AND
DAMAGING WIND GUSTS.

...SYNOPSIS...

VIGOROUS SHORTWAVE TROUGH MOVING ESEWD THROUGH CA WILL EMERGE OVER
THE SRN-CNTRL HIGH PLAINS SATURDAY NIGHT. A LEE LOW SHOULD DEEPEN
OVER THE CNTRL HIGH PLAINS SATURDAY AFTERNOON WITHIN ZONE OF
INCREASING UPPER DIVERGENCE DOWNSTREAM FROM THIS FEATURE. AT THE SFC
A DRYLINE WILL BECOME ESTABLISHED FROM WRN TX NWD THROUGH WRN KS.
WARM FRONT WILL DEVELOP NWD AND BY LATE AFTERNOON WILL EXTEND EWD
FROM THE LOW THROUGH NEB INTO THE MIDDLE MS AND OH VALLEYS. PACIFIC
COLD FRONT WILL ACCOMPANY THE SHORTWAVE TROUGH INTO THE SRN
PLAINS...EVENTUALLY OVERTAKING THE DRYLINE LATER SATURDAY NIGHT.

...WRN THROUGH NCNTRL TX...OK AND KS...

STRENGTHENING SLY LLJ ASSOCIATED WITH DEVELOPING LEE CYCLONE WILL
ADVECT RICHER MOISTURE CURRENTLY RESIDING OVER CNTRL/SRN TX NWD
THROUGH THE PLAINS WARM SECTOR BENEATH EML PLUME WITH VERY STEEP
/8-9 C/KM/ LAPSE RATES. BY LATE AFTERNOON NEAR SFC DEWPOINTS SHOULD
RANGE FROM THE LOW 60S ACROSS NRN TX AND OK TO UPPER 50S OR NEAR 60
FARTHER NORTH THROUGH KS. AS THE BOUNDARY LAYER WARMS AN AXIS OF
2000-3000 J/KG MLCAPE WILL LIKELY DEVELOP IN THIS REGION. PLUME OF
WARMER AIR AT BASE OF THE EML SHOULD CONTRIBUTE TO A SUBSTANTIAL CAP
MUCH OF THE DAY. WITH PRIMARY UPPER TROUGH REMAINING FAR WEST OF THE
DRYLINE DURING THE AFTERNOON...ANY UPPER FORCING FOR DEEP LAYER
ASCENT WILL REMAIN LIMITED TO ANY SUBTLE LEAD IMPULSES EJECTING
AHEAD OF MAIN SHORTWAVE TROUGH. HOWEVER...HEATING AND DEEP MIXING
ALONG THE DRYLINE SHOULD CONTRIBUTE TO AT LEAST ISOLATED STORMS BY
LATE AFTERNOON/EARLY EVENING.

ANY STORMS THAT CAN INITIATE DURING THE LATE AFTERNOON SHOULD BE
SOMEWHAT HIGHER BASED...ESPECIALLY WITH NWD EXTENT THROUGH WARM
SECTOR GIVEN 20+ TEMPERATURE-DEWPOINT SPREADS. THIS AND MODEST FLOW
ALOFT SUGGEST STORMS WILL PROBABLY BE OUTFLOW DOMINANT. WINDS ALOFT
WILL INCREASE AND THE LLJ WILL STRENGTHEN DURING THE EARLY EVENING
WITH SHEAR PROFILES BECOMING SUPPORTIVE OF SUPERCELL STRUCTURES.
VERY LARGE HAIL AND DAMAGING WIND WILL BE THE MAIN THREATS. A SMALL
WINDOW MAY ALSO EXIST FOR ISOLATED TORNADOES DURING THE EARLY
EVENING AS THE LLJ STRENGTHENS AND BEFORE BOUNDARY LAYER BEGINS TO
DECOUPLE.

ADDITIONAL STORMS MAY DEVELOP LATER IN THE EVENING WITH POTENTIAL
FOR UPSCALE MCS GROWTH AS DEEPER FORCING ATTENDING THE EJECTING
SHORTWAVE TROUGH AND ITS ATTENDANT COLD FRONT BEGIN TO INTERACT WITH
WARM SECTOR. THIS ACTIVITY MAY BE SLIGHTLY ELEVATED ABOVE THE STABLE
BOUNDARY LAYER BUT MAY TAP INTO SUFFICIENT MOISTURE FOR A CONTINUED
THREAT FOR LARGE HAIL AND DAMAGING WIND AS IT DEVELOPS NEWD
OVERNIGHT.

...CNTRL/ERN NEB...SERN SD AND WRN IA...

THE BOUNDARY LAYER WILL MOISTEN IN VICINITY OF THE WARM FRONT. EWD
ADVECTING EML PLUME AND DIABATIC WARMING WILL CONTRIBUTE TO FURTHER
DESTABILIZATION...BUT THE ATMOSPHERE WILL LIKELY REMAIN CAPPED MUCH
OF THE DAY...ESPECIALLY GIVEN PROXIMITY TO UPPER RIDGE. THIS LENDS
CONSIDERABLE UNCERTAINTY REGARDING THUNDERSTORM INITIATION POTENTIAL
SATURDAY AFTERNOON. MODERATE INSTABILITY IN THE PRESENCE OF STEEP
LAPSE RATES AND VEERING LOW-LEVEL WIND PROFILES ALONG/JUST NORTH OF
THE WARM FRONT SUGGEST A CONDITIONAL THREAT FOR SEVERE STORMS.
SHOULD STORMS INITIATE ALONG THIS BOUNDARY DURING THE
AFTERNOON/EARLY EVENING...SUPERCELLS WITH LARGE HAIL AND PERHAPS A
COUPLE TORNADOES WILL BE POSSIBLE. OTHERWISE...POTENTIAL WILL EXIST
FOR ELEVATED STORMS TO DEVELOP DURING THE EVENING/OVERNIGHT NORTH OF
THIS BOUNDARY WITH A THREAT FOR LARGE HAIL.

...ERN WY AND WRN SD...

A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE FROM NERN WY INTO THE
BLACK HILLS AREA OF WRN SD WHERE ELY UPSLOPE WINDS WILL EXIST
BENEATH INCREASING UPPER DIFFLUENT FLOW ALOFT. LOW-LEVEL MOISTURE
WILL REMAIN MODEST IN THE PRESENCE OF STEEP LAPSE RATES...BUT THE
THERMODYNAMIC AND KINEMATIC ENVIRONMENT APPEAR TO SUPPORT AT LEAST A
MODEST SEVERE THREAT AS STORMS DEVELOP AND SPREAD NEWD OFF THE
HIGHER TERRAIN. THIS AREA MIGHT NEED TO BE INCLUDED IN A SLIGHT RISK
IN LATER UPDATES.

..DIAL/LEITMAN.. 04/26/2014

[venture]

Day 2 Includes I-35 counties and those to the East. OKC impacts are going to be early in this Outlook, but it still covers us. Severe weather outbreak and the first high risk of the year for the US seems to be on tap.

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1254 AM CDT SAT APR 26 2014

VALID 271200Z - 281200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER AR...FAR NRN LA/NERN TX/ERN
OK/SWRN MO...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL
CONUS...

...SUMMARY...
AN OUTBREAK OF SEVERE STORMS IS POSSIBLE ON SUNDAY ACROSS PARTS OF
THE CENTRAL STATES WITH LARGE HAIL...DAMAGING WINDS...AND TORNADOES.
THE GREATEST RISK FOR STRONG TORNADOES APPEARS CENTERED FROM THE
ARK-LA-TEX TO THE LOWER MISSISSIPPI VALLEY.

...SYNOPSIS...
A VIGOROUS SHORTWAVE TROUGH CENTERED IN THE LEE OF THE SRN ROCKIES
AT 12Z/SUN WILL SUBSTANTIALLY SLOW AS IT PROGRESSES TOWARDS NEB. AN
ATTENDANT MID-LEVEL JET /AOA 50 KT AT 500 MB/ WILL
PERSIST FROM THE DESERT SW...CURLING NWD FROM THE RED RIVER TO THE
MO VALLEY. AT THE SURFACE...A CYCLONE SHOULD DRIFT EWD OVER THE
CNTRL PLAINS WITH A WARM FRONT ARCING EWD ACROSS THE CORN BELT TO
THE LOWER OH VALLEY. A DRYLINE/WEAKENING PACIFIC COLD FRONT SHOULD
REACH ERN KS/OK INTO DEEP S TX IN THE LATE AFTERNOON.

...MO VALLEY TO THE WRN GULF COAST...
OVERALL SCENARIO HAS NOT CHANGED MUCH FROM PREVIOUS OUTLOOK WITH
GRADUALLY INCREASING CONFIDENCE IN A POSSIBLE OUTBREAK AMIDST
CONTINUED LIMITING FACTORS.

THE WARM SECTOR WILL BE INCREASINGLY BROAD/MOIST BENEATH AN EML WITH
LOWER 60S SURFACE DEW POINTS BECOMING ESTABLISHED NEAR THE WARM
FRONT AND MIDDLE TO UPPER 60S INTO THE LOWER/MID-MS VALLEYS AND
ARKLATEX BY EARLY EVENING SUN. THIS COMBINED WITH INITIALLY STEEP
MID-LEVEL LAPSE RATES AND MODERATE TO STRONG DEEP-LAYER SHEAR WILL
SUPPORT AN EXPANSIVE AREA OF ORGANIZED SEVERE STORMS.

AREAS OF CONVECTION SHOULD BE ONGOING AT 12Z/SUN FROM PARTS OF IA TO
OK. ALTHOUGH THE BULK THIS ACTIVITY SHOULD BE ELEVATED...IT SHOULD
TRANSITION TO BECOMING SURFACE-BASED AS DOWNSTREAM DIURNAL HEATING
ENSUES. CLUSTERS OF ISOLATED TO SCATTERED SEVERE STORMS WILL BE
POSSIBLE AS THIS LEAD CONVECTION LIKELY DEVELOPS EWD.

THE MOST INTENSE SEVERE STORMS SHOULD DEVELOP ALONG THE DRYLINE AND
REMNANT CONVECTIVE OUTFLOWS IN THE WARM SECTOR DURING THE AFTERNOON.
IN THE WAKE OF EARLY DAY CONVECTION...THERE REMAINS SUBSTANTIAL
UNCERTAINTY IN THE DEGREE OF DESTABILIZATION /ESPECIALLY WITH NRN
EXTENT/. NAM/GFS GUIDANCE IS INSISTENT ON DEVELOPING AT LEAST
MODERATE BUOYANCY WITH MLCAPE AOA 1000 J/KG INTO NERN KS AS
INSOLATION OCCURS ALONG THE DRYLINE AMIDST STEEP MID-LEVEL LAPSE
RATES. IF THIS WERE TO OCCUR...ROBUST MID-LEVEL DCVA WOULD FOSTER
SCATTERED STORMS FORMING BY MID-AFTERNOON INVOF KS/MO BORDER.
ALTHOUGH DEEP-LAYER WIND PROFILES SHOULD BE LARGELY MERIDIONAL
HERE...BACKED LOW-LEVEL WINDS WOULD AID IN SUFFICIENT CURVATURE TO
THE LOW-LEVEL HODOGRAPH FOR SUPERCELLS. LARGE HAIL /SOME
SIGNIFICANT/ AND AT LEAST A FEW TORNADOES APPEAR POSSIBLE. PARTS OF
THIS REGION MAY BE UPGRADED TO MODERATE RISK IN LATER OUTLOOKS IF IT
APPEARS STABILIZING EFFECTS OF EARLY DAY CONVECTION WILL NOT BE TOO
DETRIMENTAL TO THE AFTERNOON THREAT.

FARTHER S...A MORE VOLATILE THERMODYNAMIC ENVIRONMENT SHOULD EXIST S
OF ANY EARLY DAY CONVECTION /INVOF THE ARKLATEX/. WITH SURFACE
TEMPERATURES HEATING INTO THE 80S/90S ALONG/W OF THE DRYLINE IN
TX...MLCAPE SHOULD REACH 2500 J/KG JUST AHEAD OF IT. HODOGRAPHS
APPEAR QUITE CONDUCIVE TO SUPERCELLS...CAPABLE OF PRODUCING VERY
LARGE HAIL AND STRONG TORNADOES. NAM FORECAST SOUNDINGS REMAIN THE
MOST ROBUST WITH THE CO-LOCATION OF STRONG BUOYANCY AND LARGE
CURVING HODOGRAPHS. OTHER GUIDANCE SUGGESTS STRONGER KINEMATIC
FIELDS WILL BE DISPLACED FARTHER EAST /CENTERED OVER THE LOWER MS
VALLEY/. BUT WITH THE DRYLINE STALLING OR SLOWLY MOVING ACROSS NERN
TX SUN NIGHT...TRAINING CONVECTIVE CLUSTERS WITH EMBEDDED SUPERCELLS
MAY CONTINUE WELL INTO THE NIGHT. PARTS OF THIS REGION MAY WARRANT
AN UPGRADE TO HIGH RISK IN LATER OUTLOOKS.

[venture]

One thing I noticed and was picked up on another forum is that difference in how various forecasters are approaching today/Saturday. Definitely different wording when you compare the Day 2 to the new Day 1, especially when models have shown a bit more favorable setup for the nocturnal situation. I wouldn't be shocked to see things modified again on the next update when a different forecaster takes a look at it.

[venture]

Earlier models runs seem to have handled moisture return fairly. 60 degree dews are just about to Waco, so moisture return is more or less on time.

[Plutonic Panda]

Michael Armstrong's take.

https://www.facebook.com/michael.arm...340620?fref=nf

See, this is where Mike Morgan messed up, what do you if plan B fails? Or how about C? I have a stretch of plans that included more than Z all the way to an upside down U. Can't ever be too prepared and Mike Morgan should know that.

[Of Sound Mind]

Jn1780, I guess I'm not the only one who looked at that fleet and started thinking about how much all that cost - and how they pay for it.

Lots of sponsors/advertisers

https://twitter.com/okstormchaser/st...97861577003008

[Easy180]

The 5am NWS Hazard Weather Outlook says the tornado threat will decrease as the storms move east toward Central OK.

[Uncle Slayton]

This afternoon going North on Mustang road to hook up with I-40 East at the intersection at Reno I saw one of those twister suv's, the ones that look like a Cival War Ironclad and a New, to me at least, Channel 9 WX vehicle that I think was some thing like a PT Cruiser with a mini radome on top. Somebody is freaking.

You ought see the Timmermobile trying to get through the Sonic drive-through on W. Lindsey. As I've said before, I *so* wish he was either 1) a female or 2) not so male-ego driven because since guys usually name their vehicles after females, it'd be just a whole lot of fun trying to watch Emily Sutton form the sentence "now let's switch over to Reed Timmer in the Dominatrix."

Seems too chilly this morning for much hope of anything firing off, looks like OKC is a bridesmaid this time through, although I might get new windshields and paint jobs for the vehicles that won't fit in the garage.

[bchris02]

Dewpoints are in the upper 50s in the metro area. The dryline right now is well off to our west in the western part of the Texas panhandle and eastern New Mexico. I am guessing it should move eastward soon? How high do dewpoints need to be for a severe weather outbreak?

[venture]

The 60 degree dewpoint line is now almost to the Red River. Most areas are in the low to mid 50s right now. Dryline as BChris mentioned is off just to the west of Amarillo but this should mix east as some of this morning moisture mixes out this afternoon.



Short term RAP has storms firing by 6-7PM just west of the Metro area south along I-44, moving into the Metro area by 7-8PM.

[venture]

13Z HRRR at 7PM...

[FritterGirl]

Any idea on how this all bodes for tomorrow a.m.? Will storms be cleared by Marathon time?


Sent from my iPhone using Tapatalk

[Of Sound Mind]

From NWS: “Storm chances this afternoon into evening seem to be decreasing across the area. We are not sure that storms will develop at all due to strong capping (a layer of warm stable air around 6000 feet above the ground that will not allow for storm development).”

[Bunty]

The 60 degree dewpoint line is now almost to the Red River. Most areas are in the low to mid 50s right now. Dryline as BChris mentioned is off just to the west of Amarillo but this should mix east as some of this morning moisture mixes out this afternoon.

Shortly before noon, the 60 degree dewpoint line has already moved as far north as Ponca City.

[Bunty]

From NWS: “Storm chances this afternoon into evening seem to be decreasing across the area. We are not sure that storms will develop at all due to strong capping (a layer of warm stable air around 6000 feet above the ground that will not allow for storm development).”

Well, conditions can have changed by Sunday afternoon when the front will be much closer, assuming it hasn't moved on to eastern Oklahoma and Arkansas. For now, if the cap doesn't hold, at least the warm air can be useful for something by making the hail melt on the way down.

[Charlie40]

Looks like this storm system is falling apart for us. Looks like we will maybe get some rain from it and that's about it now. Everything is being scaled way back now. another Dud system, after all the hype!!

[s00nr1]

I just called off our planned chase for today. The thought of having to deal with a massive chaser circus for a relatively subpar setup doesn't get me excited. I will pop a bag of popcorn if something does go up and enjoy the view from my living room couch.

[SoonerDave]

From NWS: “Storm chances this afternoon into evening seem to be decreasing across the area. We are not sure that storms will develop at all due to strong capping (a layer of warm stable air around 6000 feet above the ground that will not allow for storm development).”

Hallelujah.

I've been out in the yard most of the morning and while the humidity is up some, it surely doesn't have that squishy, fatiguing, hard-to-put-into-words feel that a lot of storm days have. That things have scaled back is good news for everyone, except perhaps the chasers who obviously planned for the alternate.

[Easy180]

Damn...So now the over/under on Reed Timmer's name being called tonight is just 1

[venture]

Definitely a lot of pessimistic views on the chances for this afternoon and evening. I think it has been pretty clear this was never going to be a widespread day. With that in mind, I think immediately shutting down and taking what is being put out there to mean that nothing will happen is premature. One elevated severe storm with very large hail can ruin someones day pretty good. We continue to see the short term models pop some convection out in SW OK and bring it NE, the big question is how much and can it sustain itself. 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.

I've chased plenty of these days before in the past. It is a gamble. Sometimes you score a beautiful isolated cell other times you drove to Altus just to go to Braums. I probably would have done what S00nr1 did in this case - just too many starved chasers out there that as soon as one goes up, you'll have a parking lot. We also have a TON of out of town chasers down for the major outbreak this week that will follow the system east.

If anything goes we'll need to be ready, but for now just need to keep an eye on things.

[Uncle Slayton]

Damn. The demise of "The Big Outbreak" is unfortunate. Guess it's back to fence building.