Potential locally significant severe weather event Tuesday 5/24

[weatherwiz]

http://www.raob.com/

Thanks!

[NaoPos]

What's an EML?

[earthlight]

What's an EML?

elevated mixed layer

[Dark Energy]

elevated mixed layer

...usually associated with strong mid level lapse rates on the order of 7-8 C/km or more. There is also sometimes a cap just below it that has to be broken. EML's in the central plains are common, not around here. In the former areas, ML lapse rates can be on the order of 9-9.5 C/km and this was just observed over the past day or so. Just check the soundings from the southern plains. Those extreme mid level lapse rates are something I have never seen around these parts. Usually, if we get lapse rates anywhere near 7C/km, and have good moisture and shear, we are a good to go for severe. Also, of course, you need a trigger to develop the convection. Finally, as the name states - elevated mixed layer - there is dry air aloft that is rather pronounced.

[CooL]

Trying to get a look at the SPC wrf before i head to bed..Its having some issues lol

NCEP 4.0 km WRF-NMM run for SPC

The current forecast cycle is 00Z on 20110523 ; graphics finished at Mon May 23 04:11:26 GMT 2011

NOTE: A disk failure on May 23 will prevent this run from updating until May 25/00Z.

[tmagan]

KLGA RUC 22Z Tuesday.

[earthlight]

Posted this in the wrong threat earlier...but here's a snippet from the discussion i wrote this morning for the blog

Short Term

A relatively modest cold front is forecast to approach the area Tuesday in response to a shortwave trough which will eject northeastward from the Mississippi Valley. Modeling of this feature has been somewhat inconsistent, but a general consensus amongst the mesoscale models and short term ensemble means lends credence to the forecast this morning.

By 12-15z the warm front should begin to progress northward. Given the orientation of the mid-upper level flow, Tuesday should be the first heating day this spring where a westerly wind component may work towards New York City, New Jersey, and Long Island. This is confirmed by the 06z RUC which develops westerly 10m winds by 12-15z. With H85 temperatures forecast to be greater than 15C, currently feeling is that modeling is a bit too cool with surface temperatures, especially in the urban corridor. This could become especially true near the shore, as well, with the lack of a marine intrusion owing to the aforementioned westerly winds. High's generally in the mid 80's are likely all the way to just off the area beaches and even possibly towards Central Long Island.

Organized convection will become a concern by afternoon with the shortwave trough and associated vorticity providing enough forcing for ascent amidst unstable environment. SREF mean indicative of 1000+ joules of surface based CAPE as well as upwards of 1000 joules of mixed layer CAPE by 18-21z. That being said, working against the threat for organized convection is the rather mundane look to the wind profiles and the somewhat lacking kinematic support. Forecast soundings throughout the area bear only 25-30kts of 0-6km bulk shear and less than ideal effective shear profiles. The low level jet is also meager, especially near maximum diurnal heating.

Still, the thermodynamic support, coupled with a noticeable shortwave and associated vorticity, suggests convection should develop by afternoon over Eastern PA and should progress eastward towards New Jersey and New York City as well as Southeast New York and Connecticut. The lack of kinematic support suggests the severe weather threat should be at least somewhat limited, but the updrafts will have plenty of moisture and instability to work with, and the threat for very heavy rain, frequent lightning, and isolated damaging winds and/or hail stones will exist in these storms.

[Weathergun]

8z HRRR has pretty big t-storms firing SW of NYC this afternoon:

http://rapidrefresh....&adtfn=1&wjet=1

[IsentropicLift]

Entire area under slight risk today, these storms will not die as they hit the coast

[IsentropicLift]

Good CIN in place, should allow for good instability before storms break out this afternoon.

[NaoPos]

...usually associated with strong mid level lapse rates on the order of 7-8 C/km or more. There is also sometimes a cap just below it that has to be broken. EML's in the central plains are common, not around here. In the former areas, ML lapse rates can be on the order of 9-9.5 C/km and this was just observed over the past day or so. Just check the soundings from the southern plains. Those extreme mid level lapse rates are something I have never seen around these parts. Usually, if we get lapse rates anywhere near 7C/km, and have good moisture and shear, we are a good to go for severe. Also, of course, you need a trigger to develop the convection. Finally, as the name states - elevated mixed layer - there is dry air aloft that is rather pronounced.

Copy. I'm pretty squared away with the role of lapse rates, I just had a helluva time deciphering EML. It rings a bell now. I appreciate your breakdown. Can always learn and or stay sharp when we ask questions.

[IsentropicLift]

Brand new outlook, now puts 30% wind risk up to the Delmarva

[IsentropicLift]

Well, our severe chances got its first kick in the balls today from SPC. Latest shows large area of significantly higher CAPE, not sure why its being depicted as so minimal at this point...

MESOSCALE DISCUSSION 0926

NWS STORM PREDICTION CENTER NORMAN OK

1234 PM CDT TUE MAY 24 2011

AREAS AFFECTED...PARTS OF SRN NEW ENGLAND AND THE NORTHEAST

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 241734Z - 241930Z

AN ISOLATED THREAT FOR DAMAGING WIND MAY DEVELOP THIS AFTERNOON.

OVERALL MARGINAL/SPORADIC NATURE OF THE SEVERE THREAT SHOULD

PRECLUDE THE NEED FOR A WW...WITH A 20 PERCENT PROBABILITY OF

ISSUANCE BY 20Z.

SCATTERED SHOWERS AND ISOLATED TSTMS HAVE RECENTLY COMMENCED ACROSS

PORTIONS OF SRN VT THROUGH ERN/CNTRL NY INTO NRN PA WITHIN A BROADLY

CYCLONIC UPPER-LEVEL FLOW REGIME. ACTIVITY WILL LIKELY STRUGGLE TO

BECOME ROBUST GIVEN POOR MID-LEVEL LAPSE RATES OF AROUND 6 DEG C/KM

AT 700-500 MB SAMPLED IN REGIONAL 12Z RAOBS. DESPITE AREAS OF

SCATTERED TO OVERCAST CLOUD COVERAGE...POCKETS OF STRONGER HEATING

WILL RESULT IN A WEAKLY UNSTABLE AIR MASS. GIVEN MODERATE EFFECTIVE

SHEAR OF 20 TO 30 KT...OVERALL SEVERE POTENTIAL SHOULD REMAIN

MARGINAL AND PERHAPS YIELD ISOLATED DOWNBURSTS IN STRONGER CORES.

..GRAMS.. 05/24/2011

[TheTrials]

did anyone see even a shower out of this?

[rgwp96]

did anyone see even a shower out of this?

yes a late morning one that dropped .01 of rain here lol

[TheTrials]

yes a late morning one that dropped .01 of rain here lol

so I guess this was bust.