Potential significant severe weather Wednesday

[earthlight]

DAY 5...UPPER TROUGH WILL TURN SEWD THROUGH QUEBEC AND THE NERN

STATES WEDNESDAY. DESTABILIZATION WILL OCCUR AS DEWPOINTS IN THE

LOW-MID 60S ADVECT THROUGH WARM SECTOR ALONG A WLY LLJ BENEATH EWD

EXPANDING EML. STORMS WILL LIKELY DEVELOP ALONG AND IN ADVANCE OF

SEWD MOVING FRONT. STRONGER FLOW ALOFT ACCOMPANYING THE UPPER TROUGH

WILL CONTRIBUTE TO SUFFICIENT VERTICAL SHEAR FOR ORGANIZED SEVERE

STORMS WITHIN A FAVORABLE THERMODYNAMIC ENVIRONMENT.

..DIAL.. 05/28/2011

[earthlight]

This is one of the better synoptic setups we have seen in this area--with the low pressure decently far to the north--but significant height falls and southwestward extenstion of forcing for ascent along the cold front...all in juxtaposition with a moderately destabilized atmosphere and high dew points working with a strengthening low level jet.

[Isotherm]

Agreed entirely, excellent thermodynamics and mid/upper level support for a severe outbreak. I'm not excited too often for this area and its probably too early to get pumped, but I'm going to be disappointed if we don't see some strong convection w/ this set-up.

Side note - our best cold frontal T-storms tend to come w/ NW to SE propagating convection. Partially b/c the sfc wind direction would then be land based, with decent instability to the coast.

[forkyfork]

NW flow aloft allows us to have good shear with SW surface winds

SW winds aloft (like we usually have) means we need more of an easterly component to have good low level shear... and we know what happens to our instability when we have SE winds

[NorEaster27]

I am up north in the lake george area and chased a severe storm, got hit with nickle size hail.

[Thunderdude]

So far it looks good and hopefully no marine air gets in the way and the cap gets broken so nothing goes wrong for that day. There is nothing worse than having a dry cold or just getting boring rain showers then a prolong period of boring weather pattern which will feature below average temps with dry air. I will take the pleasant condition for a few days though.

[tmagan]

It is just after the infamous day for severe weather in the Northeast -- May 31^st.

[NorEaster27]

I am up north in the lake george area and chased a severe storm, got hit with nickle size hail.

got hit with another storm and more hail

[Amped]

It's speed shear not directional shear. Probably a derecho like setup. But I can see it causing plenty of damage.

[Dark Energy]

A textbook "loaded gun" sounding from OKC tonight. Imagine if we had something like this around here?

[Analog96]

Anyone else think that Apr 19, 2002 is a good analog?

[earthlight]

DAY 4...WEDNESDAY

UPPER RIDGE OVER THE NERN STATES WILL BREAK DOWN WEDNESDAY WITH

SIGNIFICANT HEIGHT FALLS AS THE SHORTWAVE TROUGH ADVANCES THROUGH

SERN CANADA. SWLY BOUNDARY LAYER FLOW WILL HAVE ADVECTED MID 60S

DEWPOINTS THROUGH THE PRE-FRONTAL WARM SECTOR BENEATH REMNANT EML

PLUME. AS CAP WEAKENS STORMS SHOULD DEVELOP AHEAD OF COLD FRONT

THROUGH NERN STATES AND NEW ENGLAND WHERE VERTICAL SHEAR ALONG SRN

PERIPHERY OF SHORTWAVE TROUGH WILL SUPPORT ORGANIZED STORMS

INCLUDING A FEW SUPERCELLS AND BOWING SEGMENTS WITHIN A FAVORABLE

THERMODYNAMIC ENVIRONMENT.

[earthlight]

The one thing bothering me a bit about this setup is how the model guidance seems to be decreasing the lapse rates as the event approaches between 00z and 18z Wednesday. If you were to loop the SREF probability of mid level lapse rate above 7.0, you would see how the chances decrease dramatically as the event approaches.

That being said--it's still a good setup..with plenty of instability and seemingly just the right amount of forcing for ascent and speed shear. So we will have to see how it all unfolds.

[Analog96]

The one thing bothering me a bit about this setup is how the model guidance seems to be decreasing the lapse rates as the event approaches between 00z and 18z Wednesday. If you were to loop the SREF probability of mid level lapse rate above 7.0, you would see how the chances decrease dramatically as the event approaches.

That being said--it's still a good setup..with plenty of instability and seemingly just the right amount of forcing for ascent and speed shear. So we will have to see how it all unfolds.

That would probably have more of an effect on hail possibilities rather than wind I would think.

[earthlight]

18z NAM is very impressive for a potential widespread severe weather event---awesome run

[earthlight]

That's over 4000 j/kg of mucape for Central and Northern New Jersey at 18z Wednesday...surface based is around 3000 joules.

[forkyfork]

this might pay us a visit later tonight

[earthlight]

this might pay us a visit later tonight

it's certainly possible--but guidance is not offering much hope. the gfs, spc wrf, ruc, and nam are all in different camps in handling the feature. the nam brings it right over our area--weaker, but with a noticeable area of strong vorticity within the mid level ridge. the spc wrf from 12z is farther north and keeps the convection over southern new england.

if i were a betting man i would argue against any strong to severe storms here--given the rising mid level heights throughout the night. but that's not to say we can't get a good distant light show from convection to the north or weakening convection heading in our direction from pa. here's the nam below showing the system at 12z tomorrow.

also important to watch this feature for potential convective debris tomorrow morning---shouldn't really inhibit the warming completely, but might cause a little bit of an issue for some areas initially. should be noted that the nam, even though it tracks the shortwave directly overhead, still got warmer for tomorrow and now has mostly everybody away from the immediate beach over 90..with ewr reaching 92+. this is in agreement with the gfs mos from 12z--the nam had been cooler.

[forkyfork]

[Stormlover74]

That complex made its way all the way from Iowa this morning

[earthlight]

Since we're making this the general convection thread (not a bad idea, just noting it) those storms to our west are really struggling at the moment--definitely verified more towards the SPC WRF--which by the way has NYC reaching 90 F tomorrow and the decaying MCS affecting only SNE this morning as weak convection.

[Dark Energy]

There is a strong tsra associated with the h5 vort over northcentral PA now. It is heading twds us. If it holds together, i can see parts of the area getting smashed within 6 hrs. It has a long way to go, but there is hope!

[earthlight]

There is a strong tsra associated with the h5 vort over northcentral PA now. It is heading twds us. If it holds together, i can see parts of the area getting smashed within 6 hrs. It has a long way to go, but there is hope!

The 00z NAM trended farther north with this h5 vort feature and the ridge axis compared to it's 18z run..as has the latest few runs of the RUC and the 00z SPC WRF. I think it's more likely that it eventually heads into NE PA before weakening and moving more northeast along the building ridge. That being said it does have a southeast motion to it at the moment. We will see.

[Dark Energy]

The 00z NAM trended farther north with this h5 vort feature and the ridge axis compared to it's 18z run..as has the latest few runs of the RUC and the 00z SPC WRF. I think it's more likely that it eventually heads into NE PA before weakening and moving more northeast along the building ridge. That being said it does have a southeast motion to it at the moment. We will see.

...follow the thickness gradient at 1000-500.

[Dark Energy]

yea, so the SPC WRF weakens it as it approaches. What if its wrong? We'll see. That is a pretty good model in the super near term.

[Thunderdude]

If the area misses out on the storms for the NW tonight through tomorrow and I am worry about Wednesday setup because the back door cold front will screw things for Tuesday and the front will probably stay to the south keep the air a bit more stable. Both the NAM and GFS has the back door cold front going through area and keeping south of us and the instability with the warm humid air staying our south so that can screw everything up with getting severe weather and more likely only get showers with few embedded storms instead. I hope I am wrong Wednesday that front retreats north or the back door cold front remains just NE of the area so we could stay in the warm humid with the strong instability and good dynamics.

[Dark Energy]

http://www.spc.noaa.gov/products/outlook/day3otlk.html

[CooL]

RICHER MOISTURE WITH MID-UPPER 60S DEWPOINTS WILL HAVE ADVECTED

THROUGH THE PRE-FRONTAL WARM SECTOR BENEATH REMNANT EML. THIS WILL

RESULT IN MODERATE INSTABILITY FROM THE NERN STATES INTO THE MID

ATLANTIC REGION. WHILE VERTICAL SHEAR WILL REMAIN MODEST OVER MUCH

OF THIS REGION EXCEPT FOR MAINE...DEEP LAYER WINDS WILL GRADUALLY

STRENGTHEN AS THE UPPER TROUGH ADVANCES THROUGH THE GREAT LAKES AND

SRN CANADA. STORMS WILL LIKELY DEVELOP AHEAD OF THE FRONT AS THE

BOUNDARY LAYER WARMS. BOTH MULTICELL AND SUPERCELL STORM STRUCTURES

WILL BE POSSIBLE WITH SUPERCELLS MORE LIKELY FARTHER NWD INTO NEW

ENGLAND. DAMAGING WIND AND LARGE HAIL WILL BE THE PRIMARY THREATS.

[Mr Torchey]

Since we're making this the general convection thread (not a bad idea, just noting it) those storms to our west are really struggling at the moment--definitely verified more towards the SPC WRF--which by the way has NYC reaching 90 F tomorrow and the decaying MCS affecting only SNE this morning as weak convection.

SPC WRF FAILURE, wow mcs very healthy, and storms look to mainly hit Jersey and NYC metro, perhaps southern most new england.

[Thunderdude]

Hopefully these MCS make it down to LI.