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Pattern May: gateway to everyone's favorite season

The mountains do wonders for these things, in a bad way if you need rain! ☹️

Not necessarily, afternoon lee trough on eastern mountains can sometimes help to redevelop/trigger convection with a pattern dominated by a 500mb ridge, especially old boundaries left over, normally you get large amounts of CAPE but such little triggering in these setups along with some Capping which is why there’s flat cumulus most of the time in summer days, outflow boundary can easily break that, especially in a THETA-E ridge, and plus the MCS/outflow boundary isn’t coming from the west, but more from the north/northwest
 
Not necessarily, afternoon lee trough on eastern mountains can sometimes help to redevelop/trigger convection with a pattern dominated by a 500mb ridge, especially old boundaries left over, normally you get large amounts of CAPE but such little triggering in these setups along with some Capping which is why there’s flat cumulus most of the time in summer days, outflow boundary can easily break that, especially in a THETA-E ridge, and plus the MCS/outflow boundary isn’t coming from the west, but more from the north/northwest
Couple things about tomorrow first is the initial wave that will be moving in around mid morning. That should leave behind an outflow boundary somewhere and may help to moisten the mid levels. Second is moisture return. If we can get low level moisture to move in then we certainly could see our chances increase. If we mix out or are slow to recover there is really no chance.

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Hot off the press...June/July/August map shows above normal precipitation for northern half of NC and points north. And above normal temps for everyone. NOAA
 
Hot off the press...June/July/August map shows above normal precipitation for northern half of NC and points north. And above normal temps for everyone. NOAA
Does it look similar to this
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Couple things about tomorrow first is the initial wave that will be moving in around mid morning. That should leave behind an outflow boundary somewhere and may help to moisten the mid levels. Second is moisture return. If we can get low level moisture to move in then we certainly could see our chances increase. If we mix out or are slow to recover there is really no chance.

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Hrrr really shows that area with a dewpoint minimum around central/eastern NC, and gets a good flow of higher DPs around western NC/SC, soundings are actually supportive of strong single cell/multicellular storms, and a tad bit of some organization to them if they managed to develop, also supports large hail with colder 500mb temps, high LI, steep mid level lapse rates, just depends on whether they fire BCD71151-E943-4124-8193-032BA1B47DDD.jpegF2CD7B01-C6B7-487E-812B-E418CA18B368.png
 
Wave Friday night looks more interesting as it heads into a environment already with decent low level moisture/MUcape
 
#Winning , also not often you see 60+ dbz core pop up on the hrrr sim radar, could be a few nasty hailers tommorow with steep mid level lapses, soundings do support hail as big as golf balls with a little bit elevated 0-6km bulk shear AB0E7490-1AE3-48A2-A6BD-D431BC93DE93.jpeg
 
That slip in the mountains of NC, gonna mess up my afternoon storms 22506274-886E-40D6-8EDF-742D193EC586.png
 
That MCS is falling apart quickly now, I guess some boundaries and another disturbance this evening could trigger a few storms but I have my doubts..
 
I'm chasing in the southern Plains May 20-21, I'm really stoked about this threat. Huge boom or bust potential wrt getting discrete supercells esp w/o much of a capping inversion in place (morning clouds from the preceding day's convection could aid in keeping coverage limited however). Extremely high CAPE, deep layer and low-level shear and extremely nice hodographs, backed surface winds, w/ a ton of forcing, this could really go either way. I've seen cases like this produce anything from the coveted "string of pearls" featuring a conveyor belt of discrete, intense supercells harboring strong tornadoes to rapid evolution into a giant MCS.

This sounding wasn't contaminated by convection either... Yikes lol

A 60 KT low-level jet coupled to 4000 CAPE, 500 0-1 km SRH, 40 knots of 0-1 km shear, & low LCLs with just your everyday supercell composite of 60 & effective sig tor of 11-12.

Deer god.

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I'm chasing in the southern Plains May 20-21, I'm really stoked about this threat. Huge boom or bust potential wrt getting discrete supercells esp w/o much of a capping inversion in place (morning clouds from the preceding day's convection could aid in keeping coverage limited however). Extremely high CAPE, deep layer and low-level shear and extremely nice hodographs, backed surface winds, w/ a ton of forcing, this could really go either way. I've seen cases like this produce anything from the coveted "string of pearls" featuring a conveyor belt of discrete, intense supercells harboring strong tornadoes to rapid evolution into a giant MCS.

This sounding wasn't contaminated by convection either... Yikes lol

A 60 KT low-level jet coupled to 4000 CAPE, 500 0-1 km SRH, 40 knots of 0-1 km shear, & low LCLs with just your everyday supercell composite of 60 & effective sig tor of 11-12.

Deer god.

View attachment 19607

It’s boom or bust like you said, these big troughs especially in May can be a bad thing, having to much convection development at once thus creating a MCS, 500mb pattern somewhat similar to a 1955 setup if I’m not mistaken, anyways this sounding if things remain discrete supports very violent tornadoes, definitely supports a Moore caliber tornado, definitely a decent change of wind from sfc-1km and 3km AGL
 
It’s boom or bust like you said, these big troughs especially in May can be a bad thing, having to much convection development at once thus creating a MCS, 500mb pattern somewhat similar to a 1955 setup if I’m not mistaken, anyways this sounding if things remain discrete supports very violent tornadoes, definitely supports a Moore caliber tornado, definitely a decent change of wind from sfc-1km and 3km AGL
Yea this is going to be a case of pick your poison the messier storm mode option w/ favorable cold pool orientation wrt low-level shear vectors would lead to an extremely intense MCS, the other option is discrete, very intense supercells w/ the potential for violent, long-track tornadoes.
 
When even the cold biased GEFS (12Z) has low 90s at KATL 5/23-27 and mid to upper 90s in much of S and C GA, far N FL, and parts of C/S SC, you can say a heatwave is very likely coming with at or near alltime May highs. A few highs in the 100-102 range cannot be ruled out in places like Macon, Augusta, Columbia, Savannah, Waycross and Jacksonville.
 
Irrespective of what actually happens early next week in the southern Plains, this is about as close to a perfect z500 pattern as you'll see for a tornado outbreak in TX/OK.

ecmwf_z500a_us_5.png
 
When even the cold biased GEFS (12Z) has low 90s at KATL 5/23-27 and mid to upper 90s in much of S and C GA, far N FL, and parts of C/S SC, you can say a heatwave is very likely coming with at or near alltime May highs. A few highs in the 100-102 range cannot be ruled out in places like Macon, Augusta, Columbia, Savannah, Waycross and Jacksonville.
Last year both GFS showed ridiculous temps in the 105-115 degree range a few times and only to verify 10-15 cooler. They are both just off with temps, winter or summer
 
Last year both GFS showed ridiculous temps in the 105-115 degree range a few times and only to verify 10-15 cooler. They are both just off with temps, winter or summer

The GFS already had a run with 108-111 for parts of S GA and far N FL for late this month. That will likely end up about 10 too hot but even that is near alltime May highs for some. But the GEFS isn't normally warm biased.
 
Hopefully the Euro is out to lunch here. This is big yikes for most of us.
View attachment 19608

The 12Z Euro is similarly very hot. Alltime May records will likely be challenged in places. Hottest in May on record:

Jacksonville 100
Gainesville 101
Ocala 102
Tallahassee 102
Atlanta 97
Macon 99
Augusta 100
Savannah 101
Charleston 99
Columbia 101
GSP 100
Charlotte 98
RDU 99
Montgomery 99
 
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The 12Z Euro is similarly very hot. Alltime May records will likely be challenged in places. Hottest in May on record:

Jacksonville 100
Gainesville 101
Ocala 102
Tallahassee 102
Atlanta 97
Macon 99
Augusta 100
Savannah 101
Charleston 99
Columbia 101
GSP 100
Charlotte 98
RDU 99

Ugh can we not. I've actually been enjoying surprisingly pleasant weather lately in the heat/humidity capital of the US (Houston), looks like I'm about to pay the price for it when I come back to NC.
 
The 12Z EPS (not a warm biased model by any means) is in agreement that alltime May hot records will be challenged in much of the SE late next week into early the following week, especially for SE AL, N FL, much of GA/SC and S NC. It even has highs in the low 100s in some of E GA, N FL, and S SC on some of or all of 5/24-7! That's stupid hot. Nothing intelligent about it by any means.
 
The 12Z EPS (not a warm biased model by any means) is in agreement that alltime May hot records will be challenged in much of the SE late next week into early the following week, especially for SE AL, N FL, much of GA/SC and S NC. It even has highs in the low 100s in some of E GA, N FL, and S SC on some of or all of 5/24-7! That's stupid hot. Nothing intelligent about it by any means.
?????
 
wedges everywhere, and also gorilla hail, just saw a sounding on Monday that has a 3.8 SHIP

Lmao yeah if things stay discrete this would end up being a huge wedgefest, the parameter space of pretty much everything is maxed out, can only recall the Apr 2011 outbreak in the SE US doing that. If we don't stay discrete the other primary option isn't much better (if at all) because we'd end up w/ a very intense MCS w/ straightline winds of 90+ mph possible.
 
The 12Z EPS (not a warm biased model by any means) is in agreement that alltime May hot records will be challenged in much of the SE late next week into early the following week, especially for SE AL, N FL, much of GA/SC and S NC. It even has highs in the low 100s in some of E GA, N FL, and S SC on some of or all of 5/24-7! That's stupid hot. Nothing intelligent about it by any means.

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That MCS is falling apart quickly now, I guess some boundaries and another disturbance this evening could trigger a few storms but I have my doubts..
Mixing wins...dews only around 60 for most of the state even some ML cin in place. Not going to even get cumulus in this setup right now. Mixing out of dewpoints will continue to be a problem through the weekend with the models showing afternoon dews only around 60 for most of us. Now early next week we may not see as much mixing and i wouldn't be surprised to see some rain around Monday afternoon

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Mixing wins...dews only around 60 for most of the state even some ML cin in place. Not going to even get cumulus in this setup right now. Mixing out of dewpoints will continue to be a problem through the weekend with the models showing afternoon dews only around 60 for most of us. Now early next week we may not see as much mixing and i wouldn't be surprised to see some rain around Monday afternoon

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Playing out as expected! Drought begets drought!?46492331-FB54-4C59-88D2-53ACB1ABFE66.png
 
Playing out as expected! Drought begets drought!View attachment 19611
Gfs has some semblance of the ridge through day 16 but corn exports should be at an all time high with the rain in the plains! I do think we see this pattern reverse as we get into June with the heat ridge moving back into the SW/southern plains region but building dry conditions and heat overhead early in/before summer makes me skeptical that we break the cycle

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