Central/Western Summer Medium/Long Range Discussions

[HM]

 

Looks like we're going to have to make a decision about leaving early. The pattern looks pretty iffy after this event thru next week. Our original return date was by June 9. Which means in theory we could chase till about June 7... but not sure it's going to be worth it.

 

I think leaving sooner is probably a good idea (especially for your sanity). It looks like we have something in the 6/3-6/5 time frame. After that, the pattern has to reload and it may not get threatening again until the 10th and after.

The tropical forcing right now looks awfully familiar and it is quite possible we see another MJO pulse develop again across the IO. This time of year, the IO response is more threatening than the Indonesian response (that grows colder the deeper we move into the summer season). We probably are not done yet with outbreak potential until this wave gets out of the IO.

Either way, none of this concerns the remaining days of your trip, lol.

[CT Rain]

 

 

I think leaving sooner is probably a good idea (especially for your sanity). It looks like we have something in the 6/3-6/5 time frame. After that, the pattern has to reload and it may not get threatening again until the 10th and after.

The tropical forcing right now looks awfully familiar and it is quite possible we see another MJO pulse develop again across the IO. This time of year, the IO response is more threatening than the Indonesian response (that grows colder the deeper we move into the summer season). We probably are not done yet with outbreak potential until this wave gets out of the IO.

Either way, none of this concerns the remaining days of your trip, lol.

 

I'll be chasing 6/8-6/13 - let's hope for some fun!!

 

Models don't look bad from what I can tell. Should have some chances. Flying into DEN on 6/8 and heading wherever after. 

[N. OF PIKE]

Any updates on potential within the next week or so

[andyhb]

I've seen some interesting progs from the models recently suggesting potential next week in the Lower/Mid MS Valley region, even perhaps into Dixie Alley, which would be rather anomalous for this time of year. It's definitely a swing from last year where, if I recall correctly, we were struggling to see greater than 40 kts of H5 flow across the CONUS in June.

 

Coming off one of the more high impact Plains sequences in recent memory is definitely another change from recent years, that were more focused east of region especially in terms of casualties.

[HM]

Any updates on potential within the next week or so

 

Mid-June is growing more and more interesting as we get closer. The AAM is in the tank and the GWO should continue to orbit in the phase 8-1-2-3 octants (this transitioning GWO but looping in these phases brings a favorable pattern for central CONUS severe threats). The MJO is rounding the corner again (Atlantic-IO) with leading Kelvin Wave. It is quite possible we see yet another period of heightened severe weather, including tornadic episodes (outbreaks?), for the mid-section of the country. At some point, the threats will start making headway north as the summertime heat aids in EML advection poleward. Unfortunately, the southern Plains are not done yet in the medium range with severe threats should this new jet energy crashing into the West Coast be legit mid-month (looking increasingly likely).  

[Thunder Road]

Mid-June is growing more and more interesting as we get closer. The AAM is in the tank and the GWO should continue to orbit in the phase 8-1-2-3 octants (this transitioning GWO but looping in these phases brings a favorable pattern for central CONUS severe threats). The MJO is rounding the corner again (Atlantic-IO) with leading Kelvin Wave. It is quite possible we see yet another period of heightened severe weather, including tornadic episodes (outbreaks?), for the mid-section of the country. At some point, the threats will start making headway north as the summertime heat aids in EML advection poleward. Unfortunately, the southern Plains are not done yet in the medium range with severe threats should this new jet energy crashing into the West Coast be legit mid-month (looking increasingly likely).  

 

As long as metro areas aren't affected, sounds like to me.  I'll be out June 10-20 with school.

[HM]

As long as metro areas aren't affected, sounds like to me.  I'll be out June 10-20 with school.

 

It is possible this round avoids OKC; but, I can't comfortably say that. This weekend looks interesting for the northern Plains, assuming the moisture return is sufficient. Mid-June could see a decent cap for the urban corridor, on average, setting up supercells more in the favored western Plains. My concern is that a wave or two will eject out from the long-wave along the West Coast, cut through the Plains (temporarily putting a dent into the anticyclone) and bring a wave of severe weather/tornadoes in a widespread fashion. We'll see...

 

Edit: New 12z data coming in has the West Canadian block returning (although the exact way it arrives again differs on the modeling) in about a week.

[HM]

In fact, you may see the SPC highlight Saturday tomorrow in the extended-range. It looks pretty threatening for NE-SD-ND-MN etc.

 

If things can align properly, this will be the next mod risk day.

[andyhb]

That 12z Euro pattern through the mid/longer range looks awfully familiar, with a series of waves crashing into the west coast and an initial strong impulse ejecting out of the Rockies by the end of the run, and I agree that the Northern Plains could be under the gun later this week, that is quite an intense shortwave ejecting ESE around that time.

[andyhb]

There's your western troughing antecedent pattern showing up again on the 8-10 day GFS/Euro ensemble means. Euro definitely has a more amplified/meridional flow pattern over the CONUS than the GFS, but they do have consistency in showing a broad, strong ridge over a large chunk of the western half of the Pacific, as well as ridging with an apex around the longitude of the Hawaiian Islands allowing jet energy to spill into the Eastern Pacific/Pac NW region of North America, which would suggest another active period may be coming here eventually (in addition to the potential this weekend with a westerly/northwesterly flow event over the Northern Plains/perhaps Upper MS Valley into the Great Lakes depending on how instability and the trough evolve downstream.

 

[Minnesota Meso]

In fact, you may see the SPC highlight Saturday tomorrow in the extended-range. It looks pretty threatening for NE-SD-ND-MN etc.

 

If things can align properly, this will be the next mod risk day.

 

I went to work today at 12:15pm CDT after I saw the 06/04 12z GFS solution, and said to myself, that's the first time I have seen dews in the 60-65° range for the Northern Plains and Upper Mississippi Valley region, I kept it quiet from my coworkers, as it seemed to come out of nowhere.  After getting home from work I looked at the Euro, and it continued with the 60° dews well south of the area.  However the GEM seems to agree the GFS.

 

Looking at the 06/05 GFS it still shows dews in the 60-65 range up here.  My best guess as of 11:57 pm tuesday night is that the SPC will discuss the possibility in its 4-8 day outlook, but will come out as predictability to low.

[Minnesota Meso]

Considering Saturday 6/08 in the Upper Mississippi Valley.  By 06/09 0z the GFS shows 0-3km storm relative helicity values over eastern MN at the 350-500 range, but yet has the higher cape values over the Eastern Dakota's and encroaching into far western MN.  At the same time the Bufkit forecast sounding at MSP shows the freezing level at around 11k feet with the hail growth zone extending from there up to around 26k feet, while its not a real deep hail growth zone, the temps don't get above 10°C until about  4k feet where the LCL and LFC are located.  If however the modeling is wrong and 750-1000 cape can get into west central MN instead of being locked over the MN/Dakota border, than I think area's just west of MSP could get interesting with wind and 1 to 1.25" inch hail possible, as a nice area of difluence (sp) sets up over eastern MN.  This is based on the 6/05 18z run of the GFS, I don't trust the nam this far out, and have not looked at it.

[HM]

Things are getting "that look" even more now on the latest modeling for next week. The fear of s/wv breaking through the mean long-wave ridge is starting to come to fruition in about 5-7 days. A ramp up, again, in severe weather activity is on the way.

[CT Rain]

Things are getting "that look" even more now on the latest modeling for next week. The fear of s/wv breaking through the mean long-wave ridge is starting to come to fruition in about 5-7 days. A ramp up, again, in severe weather activity is on the way.

 

Yeah the models are showing that ridge getting beaten up on the northern side. Could be an MCS paradise up there.

[Derek30]

Yeah the models are showing that ridge getting beaten up on the northern side. Could be an MCS paradise up there.

 

I will take ANYTHING. I haven't had a thunderstorm up here since mid August of last year!

 

Looks like things should be able to re-load nicely next week with that expanding ridge. Shift it east and here come the fireworks on the Plains!

[Chinook]

Considering Saturday 6/08 in the Upper Mississippi Valley.  By 06/09 0z the GFS shows 0-3km storm relative helicity values over eastern MN at the 350-500 range, but yet has the higher cape values over the Eastern Dakota's and encroaching into far western MN.  At the same time the Bufkit forecast sounding at MSP shows the freezing level at around 11k feet with the hail growth zone extending from there up to around 26k feet, while its not a real deep hail growth zone, the temps don't get above 10°C until about  4k feet where the LCL and LFC are located.  If however the modeling is wrong and 750-1000 cape can get into west central MN instead of being locked over the MN/Dakota border, than I think area's just west of MSP could get interesting with wind and 1 to 1.25" inch hail possible, as a nice area of difluence (sp) sets up over eastern MN.  This is based on the 6/05 18z run of the GFS, I don't trust the nam this far out, and have not looked at it.

Looking at the recent models, for Saturday, I just don't think that CAPE is going to want to go up north. The GFS has 750 J/kg for a section of South Dakota. That's it for the northland. It looks like there will be a squall line forming with NW shear in Nebraska, and it may be pretty junky convection and/or elevated convection. The shear looks to be good, but I'm still not sure that there will be too many wind/hail reports. It looks like the rain will move across Iowa as elevated convection or just low-CAPE thunderstorms.

[Minnesota Meso]

Looking at the recent models, for Saturday, I just don't think that CAPE is going to want to go up north. The GFS has 750 J/kg for a section of South Dakota. That's it for the northland. It looks like there will be a squall line forming with NW shear in Nebraska, and it may be pretty junky convection and/or elevated convection. The shear looks to be good, but I'm still not sure that there will be too many wind/hail reports. It looks like the rain will move across Iowa as elevated convection or just low-CAPE thunderstorms.

 

I agree, the GFS has caved to the Euro, which is what I thought would happen, kind of hoped the GFS might win that one up in this area.  When I went to bed last night after looking at 06/06 0z runs I thought the SPC would do pretty much what they did with the day 3 outlook, including the 30% chance, due to hail and wind IMO.  After a 11hr work day and a down and dirty look look at this morning model suites and the 18z GFS, it appears to be kind of a convoluted mess.  The QPF that the euro shows near the 30% risk area, doesn't really build much cape leading up to it due to cloud cover. It will be interesting to see the new day 2 outlook.  What's more likely to be fun to watch is the south western ridge building in setting up a period of time where the ring of fire gets going, while it may not pertain to most of this sub forum except for northern MN, it looks like a MCS could get going and follow the thickness line to the east or south east, if it develops, will it be long enough for us to bring the "D" word into play.  At  any rate that would be a discussion more suited for the GL/OV sub forum and points east.

[Chinook]

Do you think we should start a thread for tomorrow?

[KSWx]

Do you think we should start a thread for tomorrow?

 

 

Do you foresee there being a large tornado threat? Local NWS office is saying the tornado threat is pretty low, for our area anyway. Main hazards are wind/hail according to them.

[Chinook]

I don't think there will be a high tornado threat. I think that it won't be all that much crazier than any other 15% wind/hail risk. The system is actually an Alberta Clipper that will form an occluded front in the afternoon as the strong convection is starting in Nebraska/Kansas. So the storms will ride the occluded front. There may be wind damage reports even in Iowa. (as well as Kansas and Nebraska.)

[Derek30]

Looks like there may be a potential severe weather event for North Dakota/Manitoba this coming Friday. Models have been pretty consistent in showing this threat since late last week. Lots of moisture streaming north ahead of the system. Could be interesting.

[Thunder Road]

Looks like there may be a potential severe weather event for North Dakota/Manitoba this coming Friday. Models have been pretty consistent in showing this threat since late last week. Lots of moisture streaming north ahead of the system. Could be interesting.

 

Instability, as modeled, is pretty minimal.  You can see the Canada cyclone occluding as the Lee cyclone becomes dominant, which might shut out North Dakota but keep Nebraska and South Dakota in play.  Thankfully 700 mb temps will be coming down again by Friday, to around 7-10 C in ND, 10-12 C in SD and northern NE, and 12-14 C in SE Nebraska, which might mean we don't have capping issues like we do now.  Of course, the GFS is still showing some areas of CIN (especially in ND) so we'll see.

 

(Personally, eastern North Dakota is one area where I'd absolutely love to chase, so I hope it ends up being good.)

[Thunder Road]

Should we just keep severe weather discussions for this week in this thread?

 

SPC goes MDT for much of SD.  Sounds like a severe MCS / nocturnal derecho threat (with 45% hatched wind).

 

 

 

 

 

 

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1134 AM CDT TUE JUN 11 2013

VALID 111630Z - 121200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE NRN PLNS/MID
MO VLY...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE N CNTRL HIGH PLNS E
INTO THE MID MS VLY...

...SYNOPSIS...
ELONGATED SUBTROPICAL RIDGE NOW EXTENDING FROM THE SRN RCKYS INTO
THE CNTRL/SRN PLNS WILL EXPAND EWD THIS PERIOD IN WAKE OF UPR
IMPULSE THAT CROSSED THE TN VLY YESTERDAY. AT THE SAME TIME...POTENT
SHORTWAVE TROUGH NOW OVER UT WILL CONTINUE ENE INTO THE NRN/CNTRL
HIGH PLNS THIS EVE...BEFORE TURNING E AS IT CRESTS THE RIDGE TO
REACH SD/NEB EARLY WED.

GIVEN THE ABOVE PATTERN...EXPECT STOUT EML...WELL-DEPICTED IN THE
MORNING RAOB DATA...TO REMAIN IN PLACE INTO TNGT FROM THE N CNTRL HI
PLNS EWD INTO MID-MS/LWR OH VLYS.

AT THE SFC...CNTRL HIGH PLNS LEE LOW SHOULD REMAIN NEARLY STNRY
TODAY BEFORE ADVANCING E ACROSS SRN NEB TNGT AHEAD OF UPR TROUGH. A
CORRIDOR OF FAIRLY RICH BOUNDARY LAYER MOISTURE AND LOW-LVL ELY FLOW
WILL PERSIST N OF A W-E FRONT EXTENDING E FROM THE LOW INTO MID-MS
VLY.

COMBINATION OF LOW-LVL MOISTURE INFLOW...SFC HEATING...AND
APPROACHING UPR TROUGH LIKELY WILL LEAD TO STRONG TSTM DEVELOPMENT
BY MID TO LATE AFTN OVER PARTS OF ERN WY AND WRN SD. THIS ACTIVITY
LIKELY WILL GROW UPSCALE INTO A SVR MCS THAT MOVES GENERALLY E ALONG
THE NRN FRINGE OF THE EML CAP AND ALONG LOW-LVL MOIST AXIS THROUGH
EARLY WED. IN THE MEANTIME...SCTD AREAS OF STRONG TO LOCALLY SVR
DIURNAL STORMS MAY OCCUR TODAY OVER PARTS OF THE EAST AND
INTERMOUNTAIN WEST. IN ADDITION...WDLY SCTD ELEVATED STORMS WITH
HAIL MAY OCCUR EARLY WED IN STRENGTHENING WAA ZONE ON NE FRINGE OF
THE EML OVER THE OH VLY.

...N CNTRL HIGH PLNS TO MID MS VLY TODAY THROUGH EARLY WED...
LOW-LVL MOISTURE WILL FURTHER INCREASE ACROSS SD...NRN NEB...ERN
WY...AND SE MT TODAY IN ELY UPSLOPE FLOW N OF STALLED FRONT/LEE LOW.
COUPLED WITH STRONG SFC HEATING AND INCREASING UPR LVL
DIVERGENCE/DCVA WITH APPROACH OF UT UPR VORT...SETUP WILL BECOME
FAVORABLE FOR STRONG TSTM DEVELOPMENT NEAR THE HIGHER TERRAIN AND
ALONG LEE TROUGH AND BY MID TO LATE AFTN. COMBINATION OF STRONG
INSTABILITY /MUCAPE TO 2500 J PER KG/ AND 40 KT WSWLY DEEP SHEAR
LIKELY WILL YIELD SCTD SUPERCELLS CAPABLE OF VERY LARGE
HAIL...LOCALLY DMGG WIND...AND TORNADOES...ESPECIALLY IN SW SD...NE
WY...AND NW NEB.

GIVEN VERY DEEP/STRONG EML...PRESENCE OF 40-50 KT UNIDIRECTIONAL WLY
MID/UPR-LVL FLOW...AND MOIST/ELY LOW-LVL FLOW...SETUP APPEARS
FAVORABLE FOR UPSCALE DEVELOPMENT INTO A SVR FORWARD-PROPAGATING/
POSSIBLE DERECHO-PRODUCING CONVECTIVE SYSTEM. SUCH A SYSTEM COULD
EXTEND A RISK FOR SVR WIND...HAIL..AND ISOLD TORNADOES E INTO NE
NEB/NW A/SE SD AREA BY 12Z WED. FARTHER E...SMALLER...SOMEWHAT
ELEVATED CONVECTIVE SYSTEMS/STORMS MAY FORM DURING THE OVERNIGHT
OVER PARTS OF IL/IND/OH IN ZONE OF STRENGTHENING WAA/MOISTURE
TRANSPORT ON NERN FRINGE OF EML.

...SRN NEW ENGLAND/LWR HUDSON VLY/NJ THIS AFTN...
SFC HEATING IN NARROW CORRIDOR OF CLEARING ON SW SIDE OF CLOUD
SHIELD ASSOCIATED WITH CAPE COD AREA SFC LOW MAY SUPPORT DEVELOPMENT
OF SCTD STRONG AFTN/EVE STORMS WITH GUSTY WINDS IN ASSOCIATED ZONE
OF WEAK LOW-LVL CONFLUENCE.

...PARTS OF GA/SC THIS AFTN...
WDLY SCTD STRONG STORMS ALSO MAY FORM IN ZONE OF WEAK ASCENT ON
TRAILING SW END OF UPR IMPULSE THAT CROSSED THE TN VLY YESTERDAY.
WIND AND THERMODYNAMIC ENVIRONMENT MAY SUPPORT AN INSTANCE OR TWO OF
LOCALLY DMGG WIND/MARGINALLY SVR HAIL.

..CORFIDI/SMITH.. 06/11/2013

 

[ZackH]

Capping looks to be an issue in most of ND for Friday, but SW Manitoba may be a bit interesting closer to the low pressure center just looking at the NAM. Not a substantial threat, and the NAM is probably a bit bullish on the instability, but interesting nonetheless.

[Srain]

The best chances appear to be off to the E of the C/W Region at this time. Tomorrow into Thursday does have a lot of potential for the Great Lakes and on E into the Mid Atlantic on Thursday.

[Derek30]

Capping looks to be an issue in most of ND for Friday, but SW Manitoba may be a bit interesting closer to the low pressure center just looking at the NAM. Not a substantial threat, and the NAM is probably a bit bullish on the instability, but interesting nonetheless.

 

Maybe a strong MCS as the evening wears on for central/eastern ND?

 

I will likely be heading out for a chase on Friday with a couple others. At this point, the SK/ND/MB border area could be interesting.

[ZackH]

That's the area I'm tentatively targeting with my group, but a lot can change by Day 4! Low level directional and speed shear looks pretty good. Mid to deep layer directional shear looks a bit messy, tho. Instability is probably slightly overdone but most likely not too much. If things can stay isolated there may be some tornado potential. Lapse rates are also not as strong as I would like, but it's hard to beat a close target.

[ZackH]

The northern target is not looking as good Friday, but the NE/SD/IA intersection and areas around it are really starting to catch my attention.  Breakable holes in the cap as early as 21z with CAPE values approaching 3000-4000 J/kg, bulk shear in the 40-50 knot range and some impressive helicity and EHI values.  Would like to see some more support at the jet stream level, but if that much instability can be realized with the shear forecast, there should be a few big storms.  We are probably going down if things hold true.

[Thunder Road]

The northern target is not looking as good Friday, but the NE/SD/IA intersection and areas around it are really starting to catch my attention.  Breakable holes in the cap as early as 21z with CAPE values approaching 3000-4000 J/kg, bulk shear in the 40-50 knot range and some impressive helicity and EHI values.  Would like to see some more support at the jet stream level, but if that much instability can be realized with the shear forecast, there should be a few big storms.  We are probably going down if things hold true.

 

That's what we have our eye on as well.  We have a tendency to bias towards High Plains threats because of their structure, and there was even some discussion for blowing off tomorrow to stay in Montana today, but thankfully we decided to pick a hotel in between so that we can attempt both days.

[brettjrob]

I'm considering tomorrow as well, but it has a few more caveats than I typically like to see for a setup two states away. Capping, frontal orientation and frontal movement (southward with time) are the big ones. There looks to be a higher ceiling than with any setup in the Plains since 5/31, but messy, unrewarding HPs seem like a distinct possibility. After so many tornado days in late May, but many of which were also messy or at least lacked great structure, that's exactly the opposite of what I'm hoping for.

 

Realistically, the medium range models only show another glancing blow from a trough late next week with similar issues, so I'm leaning toward biting. The latter half of May was a hell of a ride, but for the Plains specifically, June could potentially be an even bigger dud than last year. We'll see after tomorrow is in the books.