Isolated severe threat tomorrow across western areas?

[weatherwiz]

A warm front will slowly continue to lift northward towards southern New England during the overnight hours and is expected to stall across central/southern CT tomorrow morning as a weak area of low pressure drifts southward just to the west of southern New England. With isentropic lift increasing during the overnight period along with increasing warm air and moisture advection in the lower levels of the atmosphere PWAT's will increase and showers will continue to develop and increase in aerial coverage and intensity. With the increase of warm air advection and moisture in the lower levels of the atmosphere this will also lead to an increase in elevated instability across the region, especially with the presence of steep mid-level lapse rates in place. With this an isolated t'storm or two will be possible during the overnight period.

As we go through the morning and early afternoon hours tomorrow the big question becomes will there be any any breaks of sunshine leading to stronger surface heating? Forecast models indicate there will be breaks in the clouds across much of eastern PA/western NY/extreme SW CT and down into NJ. This seems like a strong possibility as the warm front will be to the north of these areas and surface winds and winds in the lower level of the atmosphere will be conducive to allow for breaks in the clouds. With a very warm/moist airmass in place any breaks of sun will quickly heat up the atmosphere. Across these areas sfc temperatures should get into the mid to upper 70's to possibly even close to 80F in spots. With dewpoints nearing the lower 60's and the presence of steep mid level lapse rates in place this could yield to some weak to moderate instability.

While dynamics are not particularly strong tomorrow, 0-6kkm shear on order of 20-25 knots the presence of weak to moderate instability (SBcape values on order of 1000-2000 J/KG, MUcape values on order of 1500-2500 J/KG, MLcape values on order of 1000-1500 J/KG, and LI values on order of -3C to -5C), and steep mid level lapse rates on order of 6.5-7 C/KM the atmosphere would be supportive of not only t'storms but the potential for a few of these storms to become strong to even severe. Again, dynamics aren't very strong and this will yield to less in the way of storm organization and lead to more pulse-type storms, however, if these instability values are realized some of these pulse storms could pack a punch.

While we have seen setups like tomorrow a million times and not do very much what makes tomorrow much different from these many other setups will be the presence of steep mid level lapse rates. This will make tomorrow a bit different than those other setups where the lapse rates are more marginal.

While a severe weather outbreak is extremely unlikely tomorrow, severe storms could become strong to severe with the main threat being large hail thanks to the presence of cold mid-level temperatures and steep mid-level lapse rates. The presence of somewhat drier air in the mid-levels will also help enhance the hail threat. While shear is fairly meager tomorrow there is some weak helicity tomorrow and this as well will help to enhance storm rotation and the hail threat.

Across the rest of CT (outside of southwestern CT), RI, and MA surface winds being from a more southerly/southeasterly direction as the warm front will be just to the south of these areas will yield to more in the way of cloud cover and much cooler temperatures (temps here only ranging from the upper 50's to upper 60's...warmer across central CT) and much less instability (more stable atmosphere) and the threat for a strong or severe storm here is much less limited. However, trends in the cloud cover should be watched as any breaks of sun, especially if the warm front lifts further north than modeled would increase the potential for a strong or even severe storm.

As of now this is where the highest threat for a strong or severe storm exists:

[ski MRG]

Nice work Paul. Hope you get to see some action this year.

[ineedsnow]

goodluck man tomorrow actually looks good in my opinion

[N. OF PIKE]

nice right up paul. tommorrow should be fun to watch the visible loop. paul what are you favorite links for visual loops.

i've been using aviationweather.gov but figure there is prolly something better

[weatherwiz]

Thanks everyone!

I usually just use the visible loop from ucar.

[ctsnowstorm628]

Good stuff Paul. I think coastal areas west of new haven should be included in the brown shading too. It's where that damn WF sets up.

[weatherwiz]

Good stuff Paul. I think coastal areas west of new haven should be included in the brown shading too. It's where that damn WF sets up.

Thanks!

Yeah I may have cut that off just a bit too far west, where the warm front does park itself should be a focal area as well.

[N. OF PIKE]

^{look at the storms popin up in the rochester/buffalo corridor marching east. very convective nite brewing...i was impressed with radar dong a fire works display there}

^{http://radblast-mi.wunderground.com/cgi-bin/radar/WUNIDS_map?station=BUF&brand=wui&num=6&delay=15&type=N0R&frame=0&scale=1.000&noclutter=0&t=1327800972&lat=42.940277&lon=-78.731941&label=Buffalo%2C+NY&showstorms=0&map.x=400&map.y=240&centerx=400&centery=240&transx=0&transy=0&showlabels=1&severe=0&rainsnow=0&lightning=0&smooth=0}

[weatherwiz]

The 21z SPC SREF looks pretty decent with instability tomorrow across western sections.

[weatherwiz]

Very nice stuff ongoing across western NY. sfc instability may not be there but very good MUcapes (1000-1500 J/KG) and K-Index in the lower 30's along with mlvl lapse rates of 6-6.5 C/KM, 30-40 knots of vertical shear and helicity values 200-400 m2s2 is all you need!

[ice1972]

Sweet outflow boundary on KCLE radar....

[weatherwiz]

Time for bed...can't wait to wake up and check the satellite loop. One of my favorite things to do the morning of a convective threat

Convective season is here :D

[radiator]

I'm hearing distant thunder now, and the radar is lit up pretty well...

[weatherwiz]

It actually appears that there could be some breaks a bit later on..perhaps right up to the CT River Valley.

[TalcottWx]

What do you think for BWI

[weatherwiz]

What do you think for BWI

Better instability but further displaced from the stronger shear. However, there still should be more development as the afternoon goes on. Storms will likely be pulse type given lack of shear. Hail would be the main threat I think, although there could be some strong winds in the form of microbursts when cores collapse in the strongest of cells.

[CT Rain]

lame

[CoastalWx]

lame

That's what happens when Wiz starts a thread.

[weatherwiz]

That's what happens when Wiz starts a thread.

There will be some storms around later on...not sure about SNE but to out west and perhaps getting into western/SW CT.

[ineedsnow]

suns out

[ineedsnow]

I think western sections are going to do good later on

[ChrisM]

Sunny!!!

[CoastalWx]

I think western sections are going to do good later on

Running out of time. Maybe some sct storms, but best stuff well southwest.

[Brian5671]

SEVERE BUST