NJwx85

Visible satellite loop shows a narrow area of clearing ahead of the cold front sweeping across NJ currently. Looks like the clearing will not make it much North of Rt. 80. https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&sector=ne&band=GEOCOLOR&length=12

URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 128 NWS Storm Prediction Center Norman OK 125 PM EDT Tue Apr 21 2020 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Delaware Eastern Maryland New Jersey Western Long Island New York Eastern Pennsylvania Coastal Waters * Effective this Tuesday afternoon from 125 PM until 500 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible SUMMARY...A fast-moving line of showers and thunderstorms will move across the watch area this afternoon, with the potential for locally damaging wind gusts. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 35 miles northwest of Islip NY to 40 miles south southwest of Dover DE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8).

I think it just has that appearance for the Northern counties because sometimes when cells cross over into OKX territory, Upton doesn't issue warnings. I think it's more of a case of the storms weakening as they cross the Hudson river and feel the marine influence. Good news is that shouldn't be a problem today.

The two nearest radar beams are coming from Dover and Upton. That’s part of the reason why the radar might look underwhelming.

Radar echo appearance doesn’t always tell the whole story. Had plenty of lightning with 30-40dbz echoes earlier. Not only is the line lOW topped but it’s still really far away from the OKX site and KDIX is down.

Mesoscale Discussion 0424 NWS Storm Prediction Center Norman OK 1123 AM CDT Tue Apr 21 2020 Areas affected...northeast Virginia...Maryland...Deleware...southeast Pennsylvania and New Jersey Concerning...Severe potential...Watch possible Valid 211623Z - 211830Z Probability of Watch Issuance...40 percent SUMMARY...The threat for isolated damaging wind may undergo some increase by early to mid afternoon over the Middle Atlantic region. Trends will continue to be monitored for a possible WW. DISCUSSION...A band of low-topped convection currently extends from eastern PA southwest into West Virginia moving east at around 45 kt. Activity is developing along a cold front and in association with deeper ascent attending a progressive shortwave trough. The downstream warm sector is only weakly unstable due to widespread pre-frontal rain and clouds. A relatively narrow corridor of partial clearing is occurring just ahead of the cold front, though tendency has been for dewpoints to mix down into the 30s F, due to a relatively shallow moist layer evident on the 12Z Dulles ROAB. The Wallops RAOB indicated a somewhat deeper near-surface moist layer with surface dewpoints in the upper 40s. As temperatures rise into the low-mid 60s F and where low-mid 40s near-surface dewpoints can be maintained, sufficient instability (300-500 J/kg MLCAPE) might develop to support updrafts capable of isolated damaging wind gusts. This will be promoted by inverted-V boundary layers and potential for southwesterly winds of 40-45 kt in the 1-2 km layer to be transported to the surface within some of the convective cores.

Lots of lightning strikes showing up all over Queens and the bays around Sandy Hook.

It's still one heck of a good setup for our standards. The strong lapse rates will help us overcome a lot of the instability issues.

You can see these little embedded cells popping up.

The 15z run of the HRRR shows the line blowing up as it comes down off the mountains.

Yup, had 3 or 4 good rumbles of thunder and then a burst of heavy rain. Gone now, and just some light rain.

Just had another crack of thunder here. Storm is probably developing overhead. Goes to show you how much lift is out there despite the overcast conditions.

Just had a huge crack of thunder here. Surprised the hell out of me.

SBCAPE is lagging, but we still have a good amount of MUCAPE with decent shear and lapse rates. The HRRR continues to show a spike in surface based instability as the main line approaches around 17-19z.

The mesoscale models have always had this late morning band pushing through followed by the main show a couple of hours later. Currently the cold front is all the way back in Central PA, near State College.

Sun poking through the clouds here. Latest HRRR has around 1000 J/KG of SBCAPE in NE NJ ahead of the main line. Should make for a decent squall line if it verifies given the other parameters.

SPC still has the entire area in a slight risk today.

Mesoscale models have an area of "showers" moving through early afternoon before the main show. Worried that might severely limit the amount of CAPE available. The 18z NAM backed off quite a bit on instability.

And that’s all she wrote, remaining portion of the tornado watch has been lifted. Lack of instability really ruined chances North of Philly.

Cell passing just North of Princeton remains one to watch but lightning strikes remain limited. Everything else looks DOA. Maybe a few more discrete cells can pop.

The line is really bowing out as it moves into Cape May County.

One discrete cell has popped near Doylestown. Could be one to watch as it moves generally towards the Princeton area.

Currently the strongest shear combined with a few hundred j/kg of SBCAPE are moving into Northern NJ with one more wave about to move in. If we are going to see something, this is probably going to be it. Once that passes through in the next hour things should shut off pretty quickly from West to East. Overall a bit of a disappointment out this way. I know a lot of damage has been reported on the coast so don't want to downplay things but looks like further inland the inversion won out. Things could have been a bit more interesting if the system had tracked a bit further West and we truly got warm sectored.

We will probably see one more big storm system towards the middle or end of next week as the -NAO rebounds. I doubt we see much in the way of snow as it will be late April by then, but it might bode well for more severe chances and wind threats. Then the pattern should break and Spring should finally take hold.