Slight Risk of Severe Thunderstorms in South Jersey

The recent satellite imagery shows breaks in the clouds developing in Southern New Jersey. It is also becoming more humid even throughout Central New Jersey at this hour. The result will be some increasing instability, shear, and lapse rates.

With several spokes of energy sweeping through the region and old convective boundaries from prior convection, afternoon heating should be able to fire up scattered thunderstorms and showers. Any thunderstorm has the potential to become severe. Much of New Jersey is in a 5% risk for damaging wind gusts with South Jersey placed in a 15% risk for damaging wind gusts. The 15% warrants a slight risk designation. Otherwise, the entire state is in a 5% risk for large hail and a 2% risk for a tornado. The percentages represent the chance of severe weather occurring within 25 miles of a point.

I’ll keep an eye on the Storm Prediction Center to see if they place portions of the area under a watch box. It will be important to monitor the breaks in the clouds to see how far north the sunshine occurs. Even with extensive clouds on Saturday, some areas observed some intense night thunderstorms. Therefore, with the humid air mass in place, even cloudy areas could see a thunderstorm that is near or at severe limits and thus the low probabilities from the Storm Prediction Center.

Showers and Thunderstorms For Six Days

The omega block has broken down across our region and the result has been a return to unsettled weather conditions. An area of low pressure is now crawling from the Mississippi valley into the Ohio Valley. This low pressure area will crawl at turtle speed across the Ohio Valley as the atmospheric traffic jam continues and eventually it will arrive in Maryland. Basically, as slow as the high was in position over us, it will be that slow for the low before a push to bounce this jammed traffic out occurs late next week. Gulf of Mexico and Atlantic Moisture should be able to stream into our region for the next few days, particularly Tuesday and Wednesday. Initially, through Monday, the features will be more scattered and it will hard to pinpoint the exact area for development…but more widespread rains are likely Tuesday and Wednesday when the flow will be most enhanced.

Tonight, a MCV is affecting Washington D.C. and Baltimore with very heavy thunderstorms and some dangerous cloud to ground lightning. This area appears to be moving west of New Jersey at the moment. However, some scattered showers and thunderstorms were developing to the north and east of the MCV. Therefore, there is a 30% chance of a thunderstorm between now and the morning hours.

For (daytime) Sunday, the chances for scattered showers and thunderstorms look pretty good at this moment. There is probably greater than a 60% chance of showers and thunderstorms. I do see the potential for more organization and aerial coverage as the Sunday focal point will be stronger than the focal point that we have seen today. There should also be more instability in place on Sunday. Thunderstorms could very well be slow movers and they also will have access to some decent moisture to produce heavy rainfall. This raises the concern for potential localized flash flooding and excessive rainfall. Extensive cloudiness should limit the potential for severe weather to some degree. Any ongoing showers and thunderstorms in the morning would really limit severe weather. However, should there be some peaks of sunshine; a few severe thunderstorms could develop. The Storm Prediction Center has placed southern and western areas under a “see text” probability for severe thunderstorms within 25 miles of a point.

For Monday, another round of showers and thunderstorms is likely. The severe threat will be highly dependent on convective cloud debris and any potential ongoing action from the overnight. Hail and strong wind gusts appear to be the primary threats, especially if sunshine breaks out through the cloudiness. Any thunderstorm could contain localized heavy rainfall and they could be very slow movers suggesting localized flash flooding is once again not out of the question. There could be a little less in the way of activity on Monday.

For Sunday and Monday, while we do not have any flash flood watches in effect, I could see a few polygon warnings being needed. Sometimes, watches are not posted until the day of the event when there is higher confidence of the axis zone of organized development. History suggests the higher terrain influences, but it can happen elsewhere. The week of dry weather helped, but we are still running well above average in our basins with the wet spring season. The Raritan Basin is the most vulnerable to flooding this week...especially with 3" or more this week in one shot. All you need is a soaking MCV like the one tonight in Washington D.C. and then you have streams rising to bankful.

The stationary system and frontal boundary makes the closest approach on Tuesday and Wednesday. With the flow most enhanced at this point and time, this is when the heaviest rainfall will occur and the most widespread shower and thunderstorm activity of this entire stretch. The flood threat will be highly dependent on how bad the damage is done on Sunday and Monday. However, folks living in low-lying areas, along creeks, along streams, and along rivers should be aware that quite a bit of rain could fall in some communities on top of what falls prior to this time frame.

Residual moisture and effects from this system appear to linger into Thursday and Friday. While the coverage will be less, showers and thunderstorms are still a possibility, especially during peak daytime heating. At this point, a new powerhouse storm system will be taking shape in the Western United States and shift into the Central United States on Saturday. We will probably experience our first precipitation free day on Saturday (of the next seven). A pretty nasty severe weather outbreak may take shape in the Central United States next weekend if all the ingredients can come together. This system could impact our region by Monday according to the latest long range guidance, although it may be slower in arrival overtime and further adjustments could place this system in our territory Tuesday or Wednesday.

Please remember to turn around and don’t drown if you see rising flood waters. Also, if you hear thunder, you are close enough to be struck by lightning. Move indoors immediately when you hear thunder.

Stormy Week Ahead

Showers and thunderstorms. That is the weather story for the next five days.

Several inches of rain possible the next 7 Days

Finally, we have some weather worth mentioning and discussing. After a very quiet period, the high pressure area that maintained control of fair weather in our region is breaking down. As the high pressure area breaks down, an area of low pressure will move from the Mississippi valley into the Ohio Valley. This low pressure area will move extremely slowly across that region as the atmospheric traffic jam continues. Basically, as slow as the high was in position over us, it will be that slow for the low before a push to bounce this jammed traffic out occurs late next week. Gulf of Mexico and Atlantic Moisture should be able to stream into our region for the next few days, particularly Tuesday and Wednesday. Initially, through Monday, the features will be more scattered and it will hard to pinpoint the exact area for development…but more widespread rains are likely Tuesday and Wednesday when the flow will be most enhanced.

At this point, isolated and in-significant rain showers are likely on Saturday. The models are no longer suggesting much for Saturday, delaying the arrival of this extremely slow moving weather pattern. It should be another mostly cloudy day with a peak of sunshine here and there.

For Sunday, the chances for showers and thunderstorms look pretty good at this moment. If some peaks of sunshine break through the clouds on Sunday and there is no thunderstorm activity ongoing, then some scattered severe thunderstorms would also be a possibility. Otherwise, any thunderstorm could contain localized heavy rainfall and they could be very slow movers suggesting flash flooding is not out of the question. As the case this week with the convection development that has been occurring with the same system, hail and strong wind gusts would be the main severe threats.

For Monday, another round of showers and thunderstorms is likely. The severe threat will be highly dependent on convective cloud debris and any potential ongoing action from the overnight. Hail and strong wind gusts appear to be the primary threats. Any thunderstorm could contain localized heavy rainfall and they could be very slow movers suggesting flash flooding is not out of the question.

The stationary system and frontal boundary makes the closest approach on Tuesday and Wednesday. With the flow most enhanced at this point and time, this is when the heaviest rainfall will occur and the most widespread shower and thunderstorm activity of this entire stretch. The flood threat will be highly dependent on how bad the damage is on Sunday and Monday. However, folks living in low-lying areas, along creeks, along streams, and along rivers should be aware. Some of our slower guidance keeps the chance for thunderstorms and showers for Thursday and Friday.

Turning Active Again Soon

The quite weather continues and we are not at mid-week. There just has not been much to discuss or write about lately. This should change this weekend. Basically, we are in an atmospheric traffic jam. High pressure is holding firm across our region while a strong low pressure system exists out over the Atlantic Ocean. Meanwhile, a stationary front has been nearly stationary to our southwest and that front has been responsible for significant severe weather from Ohio down through South Carolina.

The ridge that has been bouncing the thunderstorms off the invisible barrier will begin to breakdown and shift eastward, doing so very slowly. This will allow a weak front to slowly move eastward this weekend. As it makes a closer approach, thunderstorm and rain shower chances will increase. Since everything is jammed, it will also take several days to push the unsettled weather out of here.

Saturday through Tuesday look to be the days that are most unsettled at this point. Daytime heating will lead to the best shower and thunderstorm chances each day. Some days could feature some strong to severe thunderstorms and thunderstorms with locally heavy rain. Slow moving storms may pose an increased risk for localized flooding. A good Atlantic and Gulf moisture flow would only enhance the heavy rainfall threat.

Another week of no real action

This has been extremely busy week, one that saw me out on the highway for much of the time. Earlier this week, I attended a presentation given by one of the leading forecasters at the National Hurricane Center. Then I went to the annual emergency preparedness conference in Atlantic City for a few days. Friday, I had some business to attend to in Camden County. Fortunately, it was a quite week in the weather department. Wednesday was wet at times, but it was not a significant event. By the way, the Casinos in Atlantic City are absolutely dead by normal standards. I don’t ever recall being able to get parking on the lower floors of the parking garage.

Well the new week is beginning and it doesn’t look to be an active one, weather wise either. We will have a disturbance pass to our south today. The best chances of showers and thunderstorms are south of the Garden State. Perhaps a 10 to 20 percent chances exists for Millville, Cape May, and Salem. Otherwise, there will be a buildup of cumulus clouds. I don’t envision any interior watches, warnings, or advisories until at least Thursday. If anything pops up, it would be probably for frost. However, that is a far shot as I see temperatures well away from the value needed for frost formation. May 15 is the day that is usually recommended to plant outside.

High pressure takes over on Monday and holds firm through Wednesday. During this timeframe, a low pressure area will form off the New England coastline. Our region could be caught up in a wind tunnel and therefore some breezy conditions are likely during this time. It will not be the sunniest period as some clouds will likely bubble up with afternoon heating. I see signs that the high pressure area begins to nudge eastward and breakdown as the new weekend arrives and this perhaps could allow for some triggering mechanisms to begin to impact the area with showers and thunderstorms.

I see our ESNO phase turning more neutral as we head into the summer months. This introduces the possibility for less in the way of shear in the Atlantic Ocean. Of course, other factors are needed for tropical development, but this trend is worth mentioning this early in the game. Rarely do we go two years without a U.S. land falling hurricane. We have never gone three years. If we do not see a hurricane make landfall this year, it would be a first.

Thunderstorms Strongest to our West on Tuesday

A few thunderstorms are likely on Tuesday ahead of a cold front. The models have trended warmer in the past few runs and this likely means more instability. For now, the Storm Prediction Center has the greatest chances of severe weather to our west. This may change in future forecasts if the frontal timing is moved up. This biggest issue preventing severe wx at this point in our region is the arrival of the most intense forcing after dark into early on Wednesday.

However, some heavy downpours, gusty winds, small hail, and lightning remains possible with any t-storm despite low chances of severe wx.