Central/Western Summer Medium/Long Range Discussions

[patrick7032]

Looking like a pretty impressive setup on the 18z GFS on Wednesday.

The trough remains much more neutrally tilted with focused sfc cyclogenesis along the KS/OK border, and a 40-50 LLJ to east of the dryline.

I agree with you...and hail in Seattle is a good sign of the strength of the system. I uploaded some soundings. The images are "slightly" blurry...due to the cell being on low bat. You have to click on the pics to see the full image. The top sounding is Dallas...middle is Wichita Falls...last is OKC. Also uploaded is the surface cape and LI's. Cin is minimal in the soundings with good shear. I like the helicity values and LCL heights.

[patrick7032]

New 00z GFS run has the stationary front returning north as a warm front...all the way to Kansas. If this trend continues...that'll cut down the under-cutting concern.

[baroclinic_instability]

New 00z GFS run has the stationary front returning north as a warm front...all the way to Kansas. If this trend continues...that'll cut down the under-cutting concern.

 

The 00z GFS is trying its darndest to make this semi interesting synoptically. The problem is the upper level forcing is so far displaced from the warm sector strong capping will be a huge concern Wed. I will say the dryline looks like it has more potential than it did a couple days ago. If you believe the GFS the warm front/triple pt in KS has some promise as well.

 

12z ECMWF still has a surging cold front south of the Red River by Wednesday afternoon...a world apart from the GFS. For now it seems more likely the ECMWF is closer to reality...especially as the first northern stream wave...developing now across the N Plains...continues to shift south which will tend to drive the front farther southward.

[thunderman]

The 00z GFS is trying its darndest to make this semi interesting synoptically. The problem is the upper level forcing is so far displaced from the warm sector strong capping will be a huge concern Wed. I will say the dryline looks like it has more potential than it did a couple days ago. If you believe the GFS the warm front/triple pt in KS has some promise as well.

 

12z ECMWF still has a surging cold front south of the Red River by Wednesday afternoon...a world apart from the GFS. For now it seems more likely the ECMWF is closer to reality...especially as the first northern stream wave...developing now across the N Plains...continues to shift south which will tend to drive the front farther southward.

Agreed.  This could still be a significant to major event I think, but there are a lot of "what-ifs" that need to become "yeses" first.

A saw an accuwx met posted a KFSM sounding on Facebook this morning, but the freaking LFC was 2km above the LCL and approaching 100j/kg SBCIN.  After the last debacle I am not getting my hopes up yet.

[OKpowdah]

Looks to me like a repeat of last week with an even narrower window of moisture return and a very narrow window for anything severe before the CF punches south

[JoMo]

Looks to me like a repeat of last week with an even narrower window of moisture return and a very narrow window for anything severe before the CF punches south

 

What day are we talking about and where? The moisture is already available in the Gulf and low 60 dewpoints are already in TX and LA. That will surge north and the CF today will stall out. 

[baroclinic_instability]

Agreed.  This could still be a significant to major event I think, but there are a lot of "what-ifs" that need to become "yeses" first.

A saw an accuwx met posted a KFSM sounding on Facebook this morning, but the freaking LFC was 2km above the LCL and approaching 100j/kg SBCIN.  After the last debacle I am not getting my hopes up yet.

 

 

Looks to me like a repeat of last week with an even narrower window of moisture return and a very narrow window for anything severe before the CF punches south

 

 

What day are we talking about and where? The moisture is already available in the Gulf and low 60 dewpoints are already in TX and LA. That will surge north and the CF today will stall out. 

 

 

ECMWF has definitely come more inline with the GFS past 3 runs, now stalling the CF out across central OK than lifting it northward as a quasi-warm front Wed. One big difference from last event is the cold air behind this first wave is much less impressive. LL moisture is also slightly more impressive, but the cap is still a concern given the positive tilt wave config and ejection well to the NW. The SE high is also more impressive, and there is relatively decent southeasterlies even in the absence of strong surface cyclogenesis. In terms of a major event, I am not sure about that yet. Right now it looks localized at best until the front surges south and the nocturnal LLJ amps up...although the GFS warrants more attention should it verify. Interestingly the 12z ECMWF is initiating along the dryline ahead of the CF now, and the NAM, while not depicting initiation, erases nearly all CINH by late afternoon....a big difference from last event where the NAM depicted 50-150 j/kg of CINH from the start. I actually think, even as modeled right now, this event may have some potential, and looks much better on paper than last event ever did within day 4.

[patrick7032]

Looks to me like a repeat of last week with an even narrower window of moisture return and a very narrow window for anything severe before the CF punches south

I'm not sure what data you're looking at. Even the euro shows a very good moisture return...with a good shear and instability profile for southern Oklahoma into west central Texas...and points east. I guess maybe you were talking for OKC. The undercutting potential is MUCH LOWER with this event...based on current data.

[patrick7032]

ECMWF has definitely come more inline with the GFS past 3 runs, now stalling the CF out across central OK than lifting it northward as a quasi-warm front Wed. One big difference from last event is the cold air behind this first wave is much less impressive. LL moisture is also slightly more impressive, but the cap is still a concern given the positive tilt wave config and ejection well to the NW. The SE high is also more impressive, and there is relatively decent southeasterlies even in the absence of strong surface cyclogenesis. In terms of a major event, I am not sure about that yet. Right now it looks localized at best until the front surges south and the nocturnal LLJ amps up...although the GFS warrants more attention should it verify. Interestingly the 12z ECMWF is initiating along the dryline ahead of the CF now, and the NAM, while not depicting initiation, erases nearly all CINH by late afternoon....a big difference from last event where the NAM depicted 50-150 j/kg of CINH from the start. I actually think, even as modeled right now, this event may have some potential, and looks much better on paper than last event ever did within day 4.

I agree for the most part...just curious what you meant by a "localized" event. I wouldn't say this has a significant outbreak potential just yet...but think it could be respectively decent depending. The GFS post last night was just a wwhhoooaa comment type post. I think the best approach would be to use a blend of the model frontal positions and timing. Right now...based on data...I think the day 3 and 4 risks look valid...with 4 obviously being the better day. The best initiation corridor (again based on current data...even straight off the euro)...would favor a Brownwood - Wichita Falls - just north of Lawton line. Either way it should be an interesting day...seeing if stuff goes up.

[patrick7032]

Fort Worth had a nice discussion about next weeks event.

 

 AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
239 PM CDT SUN APR 14 2013

 

 

AN UNSEASONABLY STRONG UPPER LEVEL TROUGH WILL EJECT OUT INTO THE
PLAINS ON WEDNESDAY WHICH WILL SEND A COLD FRONT THROUGH THE
REGION WEDNESDAY NIGHT. AHEAD OF THE FRONT...THE AIRMASS WILL
BECOME VERY UNSTABLE WITH CAPE LIKELY BETWEEN 2000-3000J/KG WITH
LITTLE CIN REMAINING LATE WEDNESDAY AFTERNOON. GIVEN THE POSITION
AND TIMING OF THE UPPER TROUGH...THE DRY LINE SHOULD REMAIN WEST
OF THE CWA WEDNESDAY AFTERNOON...BUT SHOULD BECOME ACTIVE.
SUPERCELL STORMS ARE LIKELY TO DEVELOP AND MOVE INTO THE NW ZONES
LATE IN THE AFTERNOON WHERE HIGHEST POPS OF 30-40 PERCENT WILL
BE PLACED. AFTER SUNSET...STORMS WILL LIKELY DEVLEOP ALONG A
SOUTHWARD MOVING COLD FRONT. THIS FRONT WILL NOT BE NEAR AS COLD
AS LAST WEEK/S FRONT...AND THE CHANCE OF IT OUTRUNNING THE UPPER
FORCING AND UNDERCUTTING THE STORMS IS MUCH LOWER. MOST OF THE CWA
SHOULD SEE RAIN AND STORMS ALONG AND BEHIND THE FRONT WEDNESDAY
NIGHT AND HAVE RAISED POPS TO 50-60 PERCENT. OUTSIDE OF THE NW
ZONES THE SEVERE POTENTIAL IS A BIT MORE UNCERTAIN AT THIS TIME.

PREFER THE ECMWF TIMING AND STRENGTH OF THE FRONT...AS THIS MODEL
REALLY HAS BEEN TOUGH TO BEAT OVER THE LAST MONTH. STRONG NW WINDS
AND COLD ADVECTION SHOULD SEND LOW TEMPS INTO THE UPPER 30S
NORTHWEST TO THE 50S SOUTHEAST BY THURSDAY MORNING. ELEVATED RAIN
SHOWERS/STORMS WILL CLEAR THE REGION DURING THE DAY THURSDAY FROM
WEST TO EAST WITH CLEARING SKIES THURSDAY EVENING. WINDS WILL
REMAIN NEAR 10MPH THURSDAY NIGHT AS THE CENTER OF THE SURFACE HIGH
WILL BE OVER THE PANHANDLE. THIS SHOULD PREVENT A FREEZE OR FROST
OVER THE AREA...BUT LOWS WILL STILL DROP INTO THE 30S IN MOST
AREAS BY FRIDAY MORNING. A COOL BUT NICE DAY IS EXPECTED FRIDAY
WITH HIGHS IN THE 60S. WITH THE CENTER OF THE HIGH OVER EAST TEXAS
FRIDAY NIGHT...ANOTHER UNSEASONABLY COLD NIGHT IS EXPECTED...WITH
POSSIBLE FROST IN THE EASTERN ZONES. THE UPPER TROUGH WILL REMAIN
SITUATED OVER THE EASTERN HALF OF THE COUNTRY INTO NEXT WEEK WHICH
WILL KEEP OUR WEATHER DRY WITH GRADUALLY MODERATING TEMPS...BUT
STILL COOL FOR THIS TIME OF YEAR.

[baroclinic_instability]

I agree for the most part...just curious what you meant by a "localized" event. I wouldn't say this has a significant outbreak potential just yet...but think it could be respectively decent depending. The GFS post last night was just a wwhhoooaa comment type post. I think the best approach would be to use a blend of the model frontal positions and timing. Right now...based on data...I think the day 3 and 4 risks look valid...with 4 obviously being the better day. The best initiation corridor (again based on current data...even straight off the euro)...would favor a Brownwood - Wichita Falls - just north of Lawton line. Either way it should be an interesting day...seeing if stuff goes up.

Localized means what most folks probably think it does, localized as compared to widespread. You can, in theory, have a localized outbreak of severe weather, for instance. You seem to think that word means there is no potential, according to your post. Right now it would be unreasonable to be expecting a large outbreak of severe weather, it isn't the type of setup conducive to it. Low level wind fields are not all that strong, storm motions won't be particular fast so you can rule out long track supercells laying waste to large expanses of land like the tornado outbreak last year near this time. Capping and marginal dews in the low 60s will also not be conducive to widespread DMC, and even with solid southeasterlies, the relatively weakly forced warm sector will not lend itself to surface based rooted triple pt/warm front activity...at least for a very long time until being undercut.

[thunderman]

Just finally took  a look at the 12 GFS/EC.  I have to say, I am somewhat intrigued now across Western OK and north Texas.  Shear profiles look good and the cap isn't nuclear with even a little positive buoyancy under it.

[andyhb]

Pretty nice looking UL jet setup for the S Plains on Wednesday on the 12z GFS.

 

[patrick7032]

Localized means what most folks probably think it does, localized as compared to widespread. You can, in theory, have a localized outbreak of severe weather, for instance. You seem to think that word means there is no potential, according to your post. Right now it would be unreasonable to be expecting a large outbreak of severe weather, it isn't the type of setup conducive to it. Low level wind fields are not all that strong, storm motions won't be particular fast so you can rule out long track supercells laying waste to large expanses of land like the tornado outbreak last year near this time. Capping and marginal dews in the low 60s will also not be conducive to widespread DMC, and even with solid southeasterlies, the relatively weakly forced warm sector will not lend itself to surface based rooted triple pt/warm front activity...at least for a very long time until being undercut.

Most folks know localized in user defined based on how it's used in a sentence. I didn't mean to give the impression that I thought you were saying no potential. I just wanted to get an idea area wise what coverage you meant.The risk area is nearly 200,000 sq miles...and 827 miles long...so to me that isn't a "localized" area/threat. As for the wind fields...the 0-1km shear magnitudes are 25-35 kts...which favor supercells with sigtor POTENTIAL. Not saying it's gonna happen...but there is enough shear there. Both the euro and GFS show that. 0-6km bulk shear magnitudes of 40-50 kts are also supportive of the supercell potential. I attached a few images to stress what I meant potential wise from a shear standpoint. Soundings show the cap eroding (see earlier soundings posts)...and dews already in the lower 60s will increase to at least the mid...if not upper 60s. The LFC heights look okay...but area a little bit of a concern to me. I'll upload the AWIPS magnitude data later.

[patrick7032]

Here are the 0-1km bulk shear images. If you look at the table listed above...and previous soundings...LCLs are at roughly 450-550m. That when combined with 25-35kts of 0-1km shear supports above 60% chances of a tornado. I'm not predicting an outbreak...I'm just saying the potential is there for a decent event.

[patrick7032]

Here's a nice pic from yesterday in Alpine, TX.

[baroclinic_instability]

Most folks know localized in user defined based on how it's used in a sentence. I didn't mean to give the impression that I thought you were saying no potential. I just wanted to get an idea area wise what coverage you meant.The risk area is nearly 200,000 sq miles...and 827 miles long...so to me that isn't a "localized" area/threat. As for the wind fields...the 0-1km shear magnitudes are 25-35 kts...which favor supercells with sigtor POTENTIAL. Not saying it's gonna happen...but there is enough shear there. Both the euro and GFS show that. 0-6km bulk shear magnitudes of 40-50 kts are also supportive of the supercell potential. I attached a few images to stress what I meant potential wise from a shear standpoint. Soundings show the cap eroding (see earlier soundings posts)...and dews already in the lower 60s will increase to at least the mid...if not upper 60s. The LFC heights look okay...but area a little bit of a concern to me. I'll upload the AWIPS magnitude data later.

Localized substantial severe is what I was referencing.  You were tossing around major/significant wording, and the 200,000 sq mile slight does not represent the higher end potential. I am sure you understand that...and not sure why we are even having this discussion. Obviously nobody on this board cares about a few hailers and linear squall lines along surging cold fronts as this is a chaser-minded severe discussion board.

[andyhb]

Localized substantial severe is what I was referencing. You were tossing around major/significant wording, and the widespread slights do not represent the higher end potential. Obviously nobody on this board cares about a few hailers and squall lines.

 

Uh, just FYI, I believe that was thunderman who threw out the sig/major wording.

[baroclinic_instability]

Uh, just FYI, I believe that was thunderman who threw out the sig/major wording.

 

Either way I think we all understand the difference between localized and widespread/outbreak. A huge slight risk does not mean widespread/outbreak...at least on these forums. Sheesh. Yes, the potential certainly looks better than a couple days ago though, especially if the southern stream speed max comes out with sufficient strength to incite a cross-barrier response to aid convergence along the dryline. ECMWF looks better with said feature than the GFS/NAM.

[Stebo]

Either way I think we all understand the difference between localized and widespread/outbreak. A huge slight risk does not mean widespread/outbreak...at least on these forums. Sheesh. Yes, the potential certainly looks better than a couple days ago though, especially if the southern stream speed max comes out with sufficient strength to incite a cross-barrier response to aid convergence along the dryline. ECMWF looks better with said feature than the GFS/NAM.

 

Thankfully this is a meteorology forum and not a chase forum, which is why it isn't a localized event in my eyes along with others. Sure there might be a limited enhanced tornado risk area potentially, but the scope of severe weather reports will probably decently widespread.

[thunderman]

Either way I think we all understand the difference between localized and widespread/outbreak. A huge slight risk does not mean widespread/outbreak...at least on these forums. Sheesh. Yes, the potential certainly looks better than a couple days ago though, especially if the southern stream speed max comes out with sufficient strength to incite a cross-barrier response to aid convergence along the dryline. ECMWF looks better with said feature than the GFS/NAM.

 

To me "significant" is a moderate risk.  If all the cards come together, i could see a moderate risk event possibly.  That's all i was saying.  As I said in that post, there are a lot of "ifs" that need to become "yeses" for that to occur.

[LocoAko]

Ahhh okay. Yeah I was seeing what you were saying. I just think the surging front is less of an issue here...and I expect a moderate risk type event. Not necessarily outbreak term worthy...but a respectable event is what I was trying to imply. I loaded the images with the shear stuff just because...if anything else...I figured ppl would find it interesting...and seeing you and I had that in training...still operationally used. BTW...any more snow dumps up there...or are you guys catching a break?

 

Sure sounded like you deemed it necessary to try to "educate" him in basic severe weather forecasting to me... 

[patrick7032]

To me "significant" is a moderate risk.  If all the cards come together, i could see a moderate risk event possibly.  That's all i was saying.  As I said in that post, there are a lot of "ifs" that need to become "yeses" for that to occur.

 

 

Thankfully this is a meteorology forum and not a chase forum, which is why it isn't a localized event in my eyes along with others. Sure there might be a limited enhanced tornado risk area potentially, but the scope of severe weather reports will probably decently widespread.

I agree with both of your points...but in fairness...I can understand baro's interpretation of what I was saying...just because he knows me personally...to some extent...as does Stebo who knows me slightly (sarcasim...a first right Stebo...lol). He probably means outbreak/significant as in a HIGH RISK type event...if I'm guessing correctly. To me a good analogy is...there's fuel for the fire...more so than any event this year...we just need mother nature to strike a match. I agree thunderman as a moderate risk being significant...as operationally things "kick into high grear" here...moreso than a slight risk anyways...in terms of all the severe weather prep that we do internally and with our partners.

[Stebo]

I agree with both of your points...but in fairness...I can understand baro's interpretation of what I was saying...just because he knows me personally...to some extent...as does Stebo who knows me slightly (sarcasim...a first right Stebo...lol). He probably means outbreak/significant as in a HIGH RISK type event...if I'm guessing correctly. To me a good analogy is...there's fuel for the fire...more so than any event this year...we just need mother nature to strike a match. I agree thunderman as a moderate risk being significant...as operationally things "kick into high grear" here...moreso than a slight risk anyways...in terms of all the severe weather prep that we do internally and with our partners.

 

Yeah I would agree with this, to me a MDT risk is significant. A lot of things would have to come together in the mesoscale for this to even approach HIGH risk criteria.

[patrick7032]

Sure sounded like you deemed it necessary to try to "educate" him in basic severe weather forecasting to me... 

Not at all...I just thought what he said was moderately wrong with regard to the wind fields...and backed up my statements with images and reasoning. The way he began the paragraph was in a somewhat demeaning manor...so I thought maybe I needed to explain my reasoning more.

[thunderman]

I was beginning to wonder about you guys there for a second haha

[patrick7032]

I was beginning to wonder about you guys there for a second haha

It's all good thunderman. Anyways...back to he model data...how's that weather...lol.

[thunderman]

Just kind of curious, what do the euro hodos look like compared to the GFS?

[baroclinic_instability]

Thankfully this is a meteorology forum and not a chase forum, which is why it isn't a localized event in my eyes along with others. Sure there might be a limited enhanced tornado risk area potentially, but the scope of severe weather reports will probably decently widespread.

This is a silly conversation that is being blown out of proportion. Everybody who posts regularly on these forums understands. If you have nothing substantial to add to this disco/thread please don't post here. Widespread sig severe is NOT likely at this time. That was the clear statement that was being made. "Localized" wording is used extensively by chase mets, severe mets, SPC, etc. to distinguish between coverage of sig severe and less than sig severe (i.e., you can have widespread severe with only pockets of much more substantial sig severe...this isn't rocket science). Discussion over.

[brettjrob]

Right now I'd agree that Wednesday looks better than last Tuesday by some margin, given sustained surface-based convection that isn't undercut. But the relatively slower evolution of sfc features is still a recent model development just since yesterday, so it will take more consistency going into tomorrow and tomorrow night before I start to buy it.

 

Tuesday is also interesting given initiation, but the environment is unlikely to match what we saw last Monday for that cap bust. Either Tuesday or Wednesday could potentially yield a tornadic supercell somewhere in W OK or N TX, but the probability remains somewhat limited based on current data IMO.