Severe storms likely for NJ starting late Tuesday afternoon
SEVERE THUNDERSTORM WATCH in effect for the entire state of New Jersey until 11 p.m.
As you may know, I began my broadcast meteorology career in Oklahoma. Right in the middle of Tornado Alley — the perfect place to study the atmosphere and learn how to forecast the weather. Needless to say, severe convective storms are kind of my thing. When I saw the forecast models, soundings, and data for Tuesday here in New Jersey, I immediately thought back to those severe weather days in the Southern Plains.
Bottom line... Tuesday will be a severe weather day for New Jersey. Violent storms are likely from late afternoon through late evening. Damaging winds and torrential rain (leading to flooding) are the primary concerns. Hail and a tornado are possibilities.
Let's analyze our storm threat by the four ingredients needed for severe and/or tornado thunderstorms:
--Instability: Refers to the tendency of air parcels to rise rapidly through the atmosphere, allowing thunderstorms to form and grow rapidly. With summerlike temperatures in the 80s and midday breaks of sunshine, the atmosphere will be fully primed for some powerful storms. I don't want to get too technical, but models have promoted CAPE (Convective Available Potential Energy) of 2000 to 3500 J/kg for New Jersey, with a LI (Lifted Index) as low as about -7. (FYI, those numbers don't happen here very often!)
--Moisture: Also known as humidity. And oh yeah, you're going to feel it by this afternoon. Dew points are expected climb from the 60s to the lower 70s. A juicy atmosphere easily lends itself to torrential rain.
--Lift: An approaching cold front will serve as the spark for severe weather. The topography of northwestern New Jersey may also play a role in initializing convection over the Garden State Tuesday afternoon.
--Shear: Wind shear means that the wind blows at different speeds and/or directions at different heights through the atmosphere, which is particularly important for the formation of tornadoes. This is a "Goldilocks" variable — you need the perfect degree of shear, not too much or too little. It's precarious, but not "just right" for Tuesday — a poor wind shear setup may be our saving grace in terms of avoiding a tornado "outbreak".
All right, enough technical stuff. The severe weather recipe will be complete, so let's talk about how these loud thunderstorms will impact you:
--Most of Tuesday: Patchy dense fog Tuesday morning will give way to midday sunshine. It's going to get incredibly humid and warm, with most high temperatures 85 to 90 degrees. (We'll end up closer to 80 in North Jersey and along the Jersey Shore.) A stiff breeze out of the southwest may gust to 30 mph.
--Storm Timing: Models have been rocksteady in showing our thunderstorms will really ramp up in NW NJ at 4 p.m. (give or take). Storms will drift southward and eastward through the evening hours, reaching I-195 after 6 p.m. and the AC Expressway around 8 p.m. The highest risk for severe weather will be before sunset (8 p.m.) before storms fizzle slightly. Therefore, the highest chance of severe weather will be northwest, particularly away from the coast. Rain, in the form of "run of the mill" thunderstorms, will continue affecting central, southern, and coastal New Jersey for most of the overnight hours.
--Biggest Concerns: These thunderstorms are likely to take the form of a squall line, which are notorious for producing damaging (60-70+ mph) winds. In addition, a period of very heavy rain (several inches in less than an hour) could easily inundate storm drains and waterways and cause flooding. Large hail is possible. And there's a slight chance for a tornado too.
This is one of the dozen or so days in a given year where you have to actively monitor the ever-changing weather, especially as you disembark from work for your evening commute. We already have a Flash Flood Watch for the southern two-thirds of the state, and a Severe Thunderstorm Watch or Tornado Watch is pretty much a certainty starting Tuesday afternoon. As storms arrive, warnings will be issued, and that's when you need to seek shelter inside a sturdy building.
Please please please take Tuesday evening's severe weather threat seriously. I only break out my "strong storm language" when it's truly warranted.
As always, we'll have live severe weather coverage both on-air and online as the thunderstorms arrive.
The Rest of the Week
Unsettled and mostly soggy weather will continue for.
Tuesday night will be rainy and foggy. We'll see lingering showers throughout Wednesday as well, especially for central and southern New Jersey. It will be far less summerlike too, as temperatures fall from the lower to mid 60s in the morning into the upper 50s by the afternoon.
Previous forecasts had kept Thursday dry, but the latest models show additional showers, again mainly over Central and South Jersey. High temperatures do look to improve to the 70s on Thursday.
Another push of steady rain arrives from the south on Friday, making for another very wet day. I'm still labeling Friday as a potential washout for now. Highs will be limited to the lower 60s.
Scattered showers and thunderstorms are in the forecast for Saturday. Lots of uncertainty with temperatures, given the potential for an onshore easterly wind. We'll end up somewhere between the mid 60s and mid 70s.
Sunday looks like the shining star of this forecast. Sure, there's the chance for an isolated shower or thunderstorm. And sure, skies will remain mostly cloudy. But it will be warm and mostly dry. Look for summerlike high temperatures back in the 80s to close out the weekend.
The GFS model shows one more batch of rain on Monday before a front clears out "all the junk" and potentially brings an extended stretch of dry weather for next week.