Potential significant severe weather Wednesday

[Isotherm]

Surprised this wasn't mentioned yet, but one thing that concerns me more than any severe parameter, is that the severe outbreak pretty much busted in the Mid-West/Lakes today. For such a large geographical area covered by mdt risk and severe thunderstorm watches, one would expect the resultant report plot to look much more impressive than this:

http://www.spc.noaa.gov/climo/reports/today.html

Not saying we can't do well tomorrow, but performance of outbreaks to our west is often a precursor to what we'll see. I hope not. If we extrapolate those reports eastward, the zone most at risk would be NNE/Upstate NY, with a couple scattered clusters in our local region.

[Isotherm]

00z NAM appears to have a MCS tomorrow morning, pretty bullish actually.

[CooL]

for what its worth, probably minimal, but the RUC has been consistant on a squall line making it into the entire area

http://ruc.noaa.gov/rucnew/jsloop.cgi?dsKeys=ruc7t:&runTime=2011060101&plotName=cref_sfc&fcstInc=60&numFcsts=25&model=ruc&ptitle=RUC%20Model%20Fields&maxFcstLen=24&fcstStrLen=-1&resizePlot=1&domain=full&wjet=1

[Weathergun]

Surprised this wasn't mentioned yet, but one thing that concerns me more than any severe parameter, is that the severe outbreak pretty much busted in the Mid-West/Lakes today. For such a large geographical area covered by mdt risk and severe thunderstorm watches, one would expect the resultant report plot to look much more impressive than this:

http://www.spc.noaa....orts/today.html

Not saying we can't do well tomorrow, but performance of outbreaks to our west is often a precursor to what we'll see. I hope not. If we extrapolate those reports eastward, the zone most at risk would be NNE/Upstate NY, with a couple scattered clusters in our local region.

I saw that. I'm concerned this may be mainly to our north too.

00z NAM appears to have a MCS tomorrow morning, pretty bullish actually.

I don't trust the NAM showing/handling a MCS. The latest HRRR run at 1z doesn't have it. And I wait for the SPC WRF too come out.

http://rapidrefresh.noaa.gov/hrrrconus/Welcome.cgi?dsKey=hrrr&domain=t3&run_time=01+Jun+2011+-+01Z

[Thunderdude]

Another worry is that the cold front may come too soon and the air will dry out too fast before the thunderstorms have any time to develop. I don't like what I see with the timing of the cold front and even the pre-frontal boundary. I feel more conformable for the cold front to come tomorrow night.

[Amped]

The morning round of Tstorms may help fix the dewpoint issues.

[Stormlover74]

I mentioned that earlier. There was a weak line of showers that dissipated and the storms in Michigan seemed to rob the rest of the area of any energy in Indiana/Illinois

Surprised this wasn't mentioned yet, but one thing that concerns me more than any severe parameter, is that the severe outbreak pretty much busted in the Mid-West/Lakes today. For such a large geographical area covered by mdt risk and severe thunderstorm watches, one would expect the resultant report plot to look much more impressive than this:

http://www.spc.noaa....orts/today.html

Not saying we can't do well tomorrow, but performance of outbreaks to our west is often a precursor to what we'll see. I hope not. If we extrapolate those reports eastward, the zone most at risk would be NNE/Upstate NY, with a couple scattered clusters in our local region.

[Dark Energy]

the high ML lapse rates have arrived. All of the regional 00z raobs have LR of 7C/km or greater. Even some over 8C/km.

[Thunderdude]

the high ML lapse rates have arrived. All of the regional 00z raobs have LR of 7C/km or greater. Even some over 8C/km.

Is that a good sign or bad sign?

[NaoPos]

Is that a good sign or bad sign?

Good sign. It's our EML an really give a boost to this severe weather chance

[JonClaw]

Thread-the-needle thunderstorm event?

[HM]

I suspect a high_end SLT risk in 30 mins and a potential upgrade later today once the situation this morning is realized. The Mid Atlantic cold pool idea is looking good for the NJ to VA corridor. I think tornadoes are becoming a decent possibility across New England into NE PA.

[earthlight]

I'm still somewhat worried about the pre-frontal trough pushing a mid-level dry punch east ahead of the main forcing by around 15-18z. A bunch of the higher resolution models have been showing this for a few runs now and it's definitely a concern especially given the synoptic setup and height falls. I agree with a 30% slight risk on the initial Day 1--but I think there are too many uncertainties right now to go near a Moderate Risk. That being said..I still think this ends up a good severe weather day..especially with the GFS and SREF being so consistent with the highly unstable environment and the favorable lapse rates & 0-6km/effective shear and turning and length of hodographs.

The EML can already be noted on the latest soundings across the Great Lakes and even into Albany. This should work strongly in our favor tomorrow barring any overnight convection that moves east and has enough latent heat release to mitigate the lapse rates. Nothing really arguing strongly for this so it's not much of a concern right now..although the latest RUC does have what seems to be organized thunderstorms moving through around 12 UTC..which would certainly throw a wrench into the entire setup. Not much on radars to our west save for some isolated convection in Northwest PA. Should be watched carefully. The greatest tornado threat is definitely to the north..over Eastern NY and Western New England potentially stretching southwestward into Northeast PA. There's much more favorable 0-6km wind fields and low level turning in these areas.

I think the severe threat will eventually develop over Eastern PA, NJ, potentially towards NYC and the M/A by afternoon..it's just really a matter of when..and where that pre-frontal trough is located amidst the favorably juxtaposed thermodynamics and kinematics. We can easily develop discrete updrafts along that boundary if the front does not move too fast to the south and east. The shear is not overly strong..but it's suffice...0-6km bulk shear is 30-35kts on the 21z SREF ensemble means. If that does occur..with the storms developing west-northwest of the metro and NJ...it's going to be a very active day. With the EML it's almost like a time bomb--and once one goes off it sets off a chain reaction as the maximized cape begins to erode the cap along the periphery of stronger forcing.

Going to be an interesting day nonetheless...I am certainly excited to see it unfold.

[Thunderdude]

I suspect a high_end SLT risk in 30 mins and a potential upgrade later today once the situation this morning is realized. The Mid Atlantic cold pool idea is looking good for the NJ to VA corridor. I think tornadoes are becoming a decent possibility across New England into NE PA.

How about NYC and LI? Did they at least stand good chance for seeing thunderstorms in general let own severe storms? My worries are there will be some marine air and the direction of the storms if they from SW to NE they most of the time screw the coast.

[tmagan]

RUC KLGA 21Z Wednesday

[HM]

This seems to be an early-mid afternoon thing for N NJ into NYC, particularly between 17z-21z. The profiles are turning enough that there will likely be discrete supercells developing during this time from western New England into northeastern PA that drop southeastward into NYC. They will likely come southeastward as a broken line.

[earthlight]

By the way 5000 j/kg of MUCAPE over Central PA right now on the latest SPC mesoanalysis. Cool to see.

[HM]

By the way 5000 j/kg of MUCAPE over Central PA right now on the latest SPC mesoanalysis. Cool to see.

EMLs are the sh-t man. It's funny to think we have better instability at 6z than we do most afternoons in a typical SLT risk day.

[weatherwiz]

I'm still somewhat worried about the pre-frontal trough pushing a mid-level dry punch east ahead of the main forcing by around 15-18z. A bunch of the higher resolution models have been showing this for a few runs now and it's definitely a concern especially given the synoptic setup and height falls. I agree with a 30% slight risk on the initial Day 1--but I think there are too many uncertainties right now to go near a Moderate Risk. That being said..I still think this ends up a good severe weather day..especially with the GFS and SREF being so consistent with the highly unstable environment and the favorable lapse rates & 0-6km/effective shear and turning and length of hodographs.

The EML can already be noted on the latest soundings across the Great Lakes and even into Albany. This should work strongly in our favor tomorrow barring any overnight convection that moves east and has enough latent heat release to mitigate the lapse rates. Nothing really arguing strongly for this so it's not much of a concern right now..although the latest RUC does have what seems to be organized thunderstorms moving through around 12 UTC..which would certainly throw a wrench into the entire setup. Not much on radars to our west save for some isolated convection in Northwest PA. Should be watched carefully. The greatest tornado threat is definitely to the north..over Eastern NY and Western New England potentially stretching southwestward into Northeast PA. There's much more favorable 0-6km wind fields and low level turning in these areas.

I think the severe threat will eventually develop over Eastern PA, NJ, potentially towards NYC and the M/A by afternoon..it's just really a matter of when..and where that pre-frontal trough is located amidst the favorably juxtaposed thermodynamics and kinematics. We can easily develop discrete updrafts along that boundary if the front does not move too fast to the south and east. The shear is not overly strong..but it's suffice...0-6km bulk shear is 30-35kts on the 21z SREF ensemble means. If that does occur..with the storms developing west-northwest of the metro and NJ...it's going to be a very active day. With the EML it's almost like a time bomb--and once one goes off it sets off a chain reaction as the maximized cape begins to erode the cap along the periphery of stronger forcing.

Going to be an interesting day nonetheless...I am certainly excited to see it unfold.

Yeah we don't want that pre-frontal trough coming through too early; if it can hold until around 18z-20z I think were GOLDEN. GFS/SREFS have been indicating very steep lapse rates, excellent shear, and high instability during this time...even the NAM is on board, especially with the steep lapse rates.

Latest gFS, especially up this way is pretty sick and indicates supercell/isolated tornado potential...NAM does as well and the SPC SREF has been beefing up these odds as we close in.

We might not see the mod risk until 13z tomorrow but I think it could be close but the smarter thing is to probably wait.

The 30 knots of bulk shear down there is impressive...and up this way were looking at 40+ by mid afternoon...that would do wonders.

[Weathergun]

I think most convection we get tomorrow will be with the pre-frontal trough and not the actual cold front. Which looks like it will hold back west of until the midday hours. 3z HRRR to our west early tomorrow afternoon:

[earthlight]

Nothing too exciting on the SPC discussion at all. 30% wind probs...5% tornado and 15% hail.

..NORTHEAST STATES SWD INTO THE MID ATLANTIC

A VERY MOIST AND UNSTABLE AIR MASS WILL ALREADY BE IN PLACE THIS

MORNING ACROSS PA/NY AND SPREADING NEWD INTO SRN NEW ENGLAND. 00Z

SOUNDINGS FROM THIS EVENING SHOWED AROUND 4000 J/KG MUCAPE WITH

UPPER 60S F BOUNDARY LAYER DEWPOINTS.

SOME COOLING ALOFT WILL OCCUR AS THE UPPER TROUGH OVERSPREADS THE

REGION. BY MID MORNING...MODELS ARE ADAMANT IN PRODUCING WIDESPREAD

CONVECTION BY AROUND 15-18Z. THIS SEEMS REASONABLE GIVEN LITTLE

CAPPING IN PLACE. HOWEVER...THIS MAY PROVE A BIT DETRIMENTAL TO

OVERALL SEVERE POTENTIAL. STILL...HIGH PRECIPITABLE WATER...40-50 KT

MID LEVEL FLOW AND HEATING AHEAD OF THE DEVELOPING STORMS WILL

FOSTER DAMAGING WINDS...POSSIBLY ORGANIZED INTO ONE OR MORE

CLUSTERS. IF STORM MODE DOES NOT BECOME OUTFLOW DOMINANT...A FEW

SUPERCELLS WILL ALSO BE LIKELY CAPABLE OF A FEW VERY LARGE

HAILSTONES.

[Thunderdude]

I'm still somewhat worried about the pre-frontal trough pushing a mid-level dry punch east ahead of the main forcing by around 15-18z. A bunch of the higher resolution models have been showing this for a few runs now and it's definitely a concern especially given the synoptic setup and height falls. I agree with a 30% slight risk on the initial Day 1--but I think there are too many uncertainties right now to go near a Moderate Risk. That being said..I still think this ends up a good severe weather day..especially with the GFS and SREF being so consistent with the highly unstable environment and the favorable lapse rates & 0-6km/effective shear and turning and length of hodographs.

The EML can already be noted on the latest soundings across the Great Lakes and even into Albany. This should work strongly in our favor tomorrow barring any overnight convection that moves east and has enough latent heat release to mitigate the lapse rates. Nothing really arguing strongly for this so it's not much of a concern right now..although the latest RUC does have what seems to be organized thunderstorms moving through around 12 UTC..which would certainly throw a wrench into the entire setup. Not much on radars to our west save for some isolated convection in Northwest PA. Should be watched carefully. The greatest tornado threat is definitely to the north..over Eastern NY and Western New England potentially stretching southwestward into Northeast PA. There's much more favorable 0-6km wind fields and low level turning in these areas.

I think the severe threat will eventually develop over Eastern PA, NJ, potentially towards NYC and the M/A by afternoon..it's just really a matter of when..and where that pre-frontal trough is located amidst the favorably juxtaposed thermodynamics and kinematics. We can easily develop discrete updrafts along that boundary if the front does not move too fast to the south and east. The shear is not overly strong..but it's suffice...0-6km bulk shear is 30-35kts on the 21z SREF ensemble means. If that does occur..with the storms developing west-northwest of the metro and NJ...it's going to be a very active day. With the EML it's almost like a time bomb--and once one goes off it sets off a chain reaction as the maximized cape begins to erode the cap along the periphery of stronger forcing.

Going to be an interesting day nonetheless...I am certainly excited to see it unfold.

The threat does look very good to the west of NYC in from NJ, PA, and upstate NY. How about for the coast like LI do they at least see a very good chance for a cluster or line of strong to severe thunderstorm to make to the coast?

[earthlight]

The threat does look very good to the west of NYC in from NJ, PA, and upstate NY. How about for the coast like LI do they at least see a very good chance for a cluster or line of strong to severe thunderstorm to make to the coast?

If the storms do develop to our west-northwest they should have no problem getting to the coast.

[weatherwiz]

We'll see what the morning outlook holds once more of the questions are answered.

[tmagan]

RUC KEWR 20Z Wednesday

[weatherwiz]

Two things that could limit any tornado potential up this way are fairly high LCL's and sounding kind of have more of an inverted-v look...more suggestive of damaging winds. However, enough helicity to where storms could rotate which could enhance the threat for larger hail, especially as WBZ heights fall during the day.

[HM]

While the 6z update isn't anything noteworthy, it is a high-end SLT and sounds reasonable at this time. A broken line swings through NYC 18z-21z. At 21z, I expect a solid swath of convection from N VA/MD to southern New England. Depending upon how soon things get going and how that affects things will certainly make or break the mod risk potential. Either way, it is looking like a very active day.

[Weathergun]

5000+ j/kg SBCAPE forecast over parts of Eastern PA and NJ tomorrow afternoon, from the 3z HRRR:

[HM]

Two things that could limit any tornado potential up this way are fairly high LCL's and sounding kind of have more of an inverted-v look...more suggestive of damaging winds. However, enough helicity to where storms could rotate which could enhance the threat for larger hail, especially as WBZ heights fall during the day.

Before 20z in northern NJ, these issues are not present. There is going to be a window here for supercells from western New England into S NY, N NJ and NE PA during the early-mid afternoon I think.

[weatherwiz]

While the 6z update isn't anything noteworthy, it is a high-end SLT and sounds reasonable at this time. A broken line swings through NYC 18z-21z. At 21z, I expect a solid swath of convection from N VA/MD to southern New England. Depending upon how soon things get going and how that affects things will certainly make or break the mod risk potential. Either way, it is looking like a very active day.

I would really prefer for things to go through during the 19z to 23z period...I feel as if that period has the best combination of higher instability to go along with the stronger shear values and helicity is maximized (at least this way). This is also when the GFS/NAM start showing the mid-level front/pre-frontal trough working through and when the drying aloft occurs.

SPC makes mention of little cap tomorrow (or it might be one of the AFD's I read) but I would really prefer some cap until at least 17z or so so we can materialize sufficient heating.