Scattered Severe T-Storms to Break the Heat Wednesday

A slight risk designation for severe thunderstorms has been issued for our entire area on Wednesday. Scattered thunderstorms will bring an end to our excessive heat. Several parts of New Jersey by late afternoon on Wednesday will reach 90 degrees or higher for the third day in a row, making this the first official heat wave of 2011.

The Storm Prediction Center has given us a high-end slight risk designation in the day two outlook. A 15% and 30% probability of severe weather warrants a slight risk of severe weather in the day two outlook. Much of New Jersey is under a 30% probability of severe weather occurring within 25 miles of a point. Most of the time when we are under a slight risk, we are placed within a 15% probability, so the threat is higher than normal at this time. Further evaluation will be done by the Storm Prediction Center on Wednesday Morning when we will be under the day one outlook which breaks the severe weather down by phenomena and gives a specific probability to each phenomenon.

While some large hail is possible, the main threat on Wednesday will be damaging wind gusts. The non-severe thunderstorm threats of dangerous cloud to ground lightning and brief torrential rains are likely with any thunderstorms.

Hot and Humid, T-Storms to Break The Heat

A heat advisory has been issued starting Monday at 12:00 PM EDT for Camden, Gloucester, Mercer, and Northwestern Burlington Counties. An excessive heat watch has been issued from Tuesday at 12:00 PM for Camden, Gloucester, Mercer, and Northwestern Burlington Counties through Wednesday Night.

For the advised and warned counties, heat indices will top out around 100 degrees for several hours on Memorial Day and around 105 degrees on both Tuesday and Wednesday. Temperatures will likely be around 92 to 95 degrees each day. The coastline could be a few degrees cooler with the cool ocean still influencing the beaches, but with a more southwesterly wind component, this may not happen on at least one of these days of the interior heat wave. While it will be equally hot in some of the counties not under an alert for heat, one must keep in mind that the criteria is lower in the urbanized areas due to the census data suggesting lower income around Trenton and Camden. Unfortunately, many in the alerted counties do not have access to air conditioning. Also, the temperatures drop slower in this area at night due to the urbanized environment as pavement doesn’t allow for ideal cooling.

Thunderstorm chances:

A shallow cold front on Monday will bring the chance for isolated pop-up thunderstorm activity. The models have been decreasing the chance for a thunderstorm after ratcheting it up on Saturday. Any thunderstorm that can form will have plenty of access to strong instability due to strong warming. The storms will not only have a poor focus, but they will also have to fight a cap that will be in place. Chance is about 20 to 30 percent.

Tuesday, heat and humidity related isolated thunderstorm. Chance is about 10 to 20 percent.

Wednesday, a strong cold front arrives to break the heat. This is the best chance of a thunderstorm of the next seven days. These thunderstorms have a decent shot of producing hail and strong winds, perhaps to severe limits. The chance of a thunderstorm is about 60 percent.

Chance of a Thunderstorm on Saturday

Tonight, there is still about a 30% chance of a thunderstorm in Northwestern New Jersey. Otherwise, the latest radar trends show that thunderstorms will mainly just miss this area unlike last night. Central Pennsylvania and Maryland is yet again getting quite a pounding...but these storms are not moving on as big of a northwest angle.

Thunderstorms are again possible on Saturday. The model guidance is suggesting that this will be the greatest threat over the past several days for thunderstorms and the chances are not all that high. There is a 40% chance of a thunderstorm tomorrow and this would include just about every location. Some isolated strong to severe thunderstorms will be possible if sufficient sunshine occurs.

Otherwise: heatwave begins on Sunday for some and lingers into next Wednesday. While there will be a 10 to 20% chance of a thunderstorm on Sunday through Tuesday with the heat and humidity...the best chance for a severe weather outbreak and widespread thunderstorms will be on Wednesday when a powerful cold front will bring an end to the heat and cool us off by about 10 to 15 degrees for Thursday.

More Severe T-Storms Possible Today, ESP. NW Again

Parts of Northwestern New Jersey into North-Central New Jersey will be spending the day evaluating the storm damage and cleaning up after powerful thunderstorms downed trees and produced hail up to the size of 1.50” in diameter.

Another day of thunderstorms, some severe, is expected, especially in the same areas that got pounded yesterday. There are a couple of reasons for the threat area being where it is. First, a stalled cold front has failed to make much eastward progress and while a bit further east today…it is not far enough east to shift the focus to the coast. Second, the southerly wind is bringing in oceanic air right along the eastern counties keeping temperatures several degrees cooler and the air more stable at the coast.

As mentioned…today’s front is a bit further to the east…so some a few isolated thunderstorms could make it a bit closer to the heart of the region later tonight and they could be severe with remaining instability. Yesterday’s thunderstorms got much further than the model guidance indicated and were much stronger, hence the problems in Northwestern New Jersey. Meanwhile, the edges of the area such as those in Hunterdon County will probably see late afternoon and evening thunderstorms that are potentially going to be severe.

Heatwave soon?

The cold front that was projected to be stalling across or just south of our region by the model guidance this week moved much further to the south, allowing for some pretty tranquil afternoons overall. We did have a few isolated thunderstorms on Tuesday. Today, we did not have any thunderstorms. We did have some cumulus clouds today.

The front will return as a warm front. As it does so, thunderstorms, isolated, are possible Thursday and Friday. The front will be driven by a low pressure center in the Great Lakes region (a familiar site this year) and it will drive a cold front towards New Jersey on Saturday and Sunday. The one problem is the front will never move through our region through Memorial Day weekend. Therefore, afternoon daytime heating could spark scattered showers and thunderstorms. It could also get quite hot ahead of the cold front, especially the latter half of Memorial Day weekend. It will not be until the middle of next week that a cold front actually swings through our region. It is possible that some areas see three consecutive days of 90 degree weather which means a heat-wave is not out of the question starting Sunday and lasting into Tuesday or Wednesday. This is considerably different from the model projections earlier in the week which showed the weekend cold front pushing offshore allowing for cooler air.

A week of thunderstorms

An onshore flow and a warm front to our west have really done a good job locking in the cooler in the eastern counties of New Jersey. Temperatures have been stuck in the middle and upper fifties in most of the eastern counties. Meanwhile, lower to mid sixties exist in the Central and Southern New Jersey interior. The onshore flow will not reverse itself until a stubborn warm front makes forward motion to the northeast. This will not happen until shortly after sunrise and therefore, fog could settle in for several areas until the wind shift happens. A northeast breeze or any scattered showers with the warm front may tend to keep the fog from become dense in some locations or widespread. But there is a chance of some thick fog in some areas if mixing relaxes.

The warm front should clear the southwestern areas of New Jersey first with the Central New Jersey counties following. There could be some sharp differences north and south of the frontal boundary. Clearing skies should follow the warm front passage and with the gates open for a southerly flow, a quick rebound in the temperature department is anticipated. The warm sector counties will at least approach 80 degrees, if not exceed it. Pieces of energy will ride along the warm front and since the front will be just north of our area, we will be affected by energy pieces. When disturbances ride along a warm front and you are directly south of it, it is typical for severe thunderstorms to develop. If we bake for a few hours, there is no doubt surface based instability will develop in the afternoon and linger through the evening. Storm coverage will be scattered. Damaging wind gusts, large hail, and even a tornado is all on the table.

A cold front approaches the region on Tuesday. However, any morning fog should give way to sunshine and a very warm and humid day. Mid to upper eighties can be expected. This will once again allow instability to increase and therefore thunderstorms and showers will develop in a pre-frontal trough in the afternoon and evening. The cold front approaching the warm sector and some waves on the front helping to energize it suggests another potential for severe thunderstorms. Some thunderstorms may produce heavy rainfall and localized flooding, especially with the rain from last week lowering the amounts needed for rain to begin to cause flash flooding and flooding.

On Tuesday Night through Thursday, the cold front stalls right over or just south of the region. Waves of energy will ride along the front and therefore showers and thunderstorms will possible throughout the entire period. The exact stalling point has not been determined. If some areas remain in caught in the warm sector, there will be an increased risk for stronger thunderstorm activity and they will also be more humid. But even right along and north of the front, thunderstorms on the strong and heavy side will be possible. Heavy rainfall is also a concern during this period as some thunderstorms could train over the same locations. Areas north of the front may see a reduced chance of storms and a nice day…maybe Thursday could be the day for that?

The stalled front then returns to the north as a warm front on Friday. Warm air advection showers and thunderstorms will be possible. A cold front will move through the region on Sunday and will be the trigger for showers and thunderstorms on Saturday and especially on Sunday. I wonder if this front will clear the region for Memorial Day. More severe weather and flooding concerns will exist during the weekend.

Thunderstorms This Afternoon and Tonight?

A backdoor cold front this afternoon and this evening will help to cause enough lift in the atmosphere for widely scattered showers and thunderstorms. Some of the higher resolution modeling is suggesting thunderstorms will be confined to Northern and North-Central New Jersey today. It is here where the best forcing will be located and it is reasonable to assume this is the highest threat area for convection.

However, there are a few higher resolution models that are suggesting activity region-wide. Given the past several days, the moisture content of the air, and the current temperatures: I think the activity will not just be confined to the North through the late afternoon and evening hours. Not everyone will see thunder and rain today, but some will.

I think the sea-breeze front will help to aid in the lift and cause some possible additional thunderstorm development. The radar is already showing the first signs of a sea breeze front, although convective temperatures have not been reached yet to spark t-storms.

Where thunderstorms form: Heavy rainfall, cloud to ground lightning, hail, and gusty winds will be possible.

Chance of T-Storms Every Single Day of the Next Seven!!

Another round of showers and thunderstorms will be possible on Saturday. These storms may be widely scattered. They will be associated with a weak backdoor cold front moving in from the northeast. Our northeastern counties have the best chance for thunderstorms…along with the coastline. With sunshine expected on Saturday and temperatures expected to rise into the seventies, some instability will be present and a few strong thunderstorms cannot be ruled out. The latest high resolution modeling is not showing the most impressive organization and more showers than thunderstorms. Hail would be the main severe threat tomorrow, along with gusty winds if a thunderstorm intensifies to that level. Still, some locally heavy rainfall can be expected.

A warm front arriving later on Sunday will cause some showers and maybe a thunderstorm to develop in the afternoon and night into Monday Morning. Some cloud to ground lightning and heavy rainfall is possible where the thunderstorms develop.

We are going to be put right into the center of an active storm track ahead of a sluggish cold front Tuesday through Friday. Waves of low pressure/spokes of energy will impact our region and combine with the daytime heating of each afternoon to produce thunderstorms and showers. With temperatures expected to rise into the eighties and sunshine prior to cumulous and cumulonimbus cloud development, instability will allow surface based CAPE to increase and lapse rates to increase at both low and mid-levels. This suggests at least widely scattered strong to severe thunderstorms each afternoon and evening. More focused and widespread activity will center around forcing mechanisms that are able to provide decent lift and determining these will be the day before or day of the event.

With good moisture content in the air and perhaps some slow movement of the thunderstorms, some flash flooding will remain a strong possibility. Now with the previous rains, the ground is much more susceptible to flooding and flash flooding. Again, the Passaic and Raritan Basins are the most vulnerable to flooding. But even our other basins could flood if there are new jackpot zones and storms yield three to four inches over a localized area.

More Severe, Heavy T-Storms on Friday

Showers and thunderstorms will once again be possible today. After morning fog burns off, some peaks of sunshine are likely. This will once again set the stage for afternoon and evening thunderstorms that could approach severe limits. Large hail and an isolated tornado will once again be possible, along with a hit or miss strong gust of wind. We have really been lucky so far as tornadoes have occurred in Maryland and Pennsylvania. Flash flooding could once again be a threat as well as storms will move slowly and contain very heavy rainfall. A few pockets on Thursday picked up copious amounts of rain in real localized pockets. The model guidance shows slightly less coverage today and the better chances in the northeastern parts of New Jersey. But honestly, due to the position of the low, New Jersey may see more activity today than on Thursday where 70 percent was focused in Pennsylvania and Maryland down through Delaware.

On Saturday, an isolated thunderstorm still cannot be ruled out. This could be a day where the boardwalk ends up with more activity than the interior or the storms fire up just offshore.

For Sunday, a warm front arriving could produce a few widely scattered showers. On Monday, we will be in the warm sector at this point, bearing nothing changes. On Tuesday, a cold front will begin to approach the region. There are some signs that this front could move slowly or become stationary in our region for Wednesday and Thursday. We would be stuck in the southerly flow and conditions could become quite warm and humid. Showers and thunderstorms will be possible on Tuesday and especially Wednesday and Thursday. More opportunities for severe weather and flooding appear to be on the table.

Slight Risk for Severe Weather Today

Another last minute slight risk designation from the Storm Prediction Center, but this one was somewhat expected. Sunshine has developed across much of the region leading to steepening lapse rates and increase surface based CAPE. In other words…instability is increasing.

This afternoon, we have a few factors that will come together. A cold pool aloft and a low freezing level will allow for hail to be a potential with several thunderstorms, some of which could be large in nature. In addition, shear will allow for perhaps an isolated tornado/spin-up. Obviously, a few storms could also produce damaging straight-line winds. I am concerned that one or two of these cells could produce hail up to the size of golf balls.

A weather watch is being considered for parts or all of the region. We will continue to follow the developments.

More Thunderstorms on Thursday, These Could be Severe

Bands of thunderstorms impacted much of New Jersey on Wednesday. Much of area received 0.60” to 1.50” of rain. Northeastern New Jersey received the jackpot with 3” to 4” of rain. Southwestern New Jersey did not do as well with amounts under one-half inch. When added to the rain totals since Monday, some areas are entering the 3” to 6” range….again thus far mainly in Northeastern New Jersey. The Raritan and Passaic River basins will probably experience some flood warnings in the next several hours, if not tomorrow…especially if additional heavy rain occurs….although the damage may have already been done in Northeastern New Jersey.

New Jersey escaped the severe weather and just narrowly. A rare tornado occurred in Northeast Philadelphia. This tornado was the ninth tornado ever in Philadelphia and the last one to occur was back in 1999. This same thunderstorm moved over Burlington County and the touchdown occurred moments after the storm crossed the Delaware River.

Confidence is increasing that severe weather could be a possibility this afternoon and early this evening. Both the GFS and NAM model from 00z agree on thunderstorm development in our area at or several hours before 6:00 p.m. This is followed by some sunshine and breaks in the cloudiness for the first time in days for some portions of our area. There could be some areas of dense fog in the morning and this may limit the sunshine initially. The sunshine should increase the instability and cause the atmosphere to become fairly unstable. Shear will exist along with plenty of moisture. This cold pool will also be settling along with a lower freezing level. Therefore, large hail and isolated tornadoes…in addition to damaging wind gusts cannot be ruled out. Highs will rise into the mid-seventies.

With the threat of slow-moving thunderstorms and plenty of moisture in existence, some very excessive rain amounts could occur. But these thunderstorms will be scattered and some communities could not see much in the way of measurable rain while others are observing flash flooding. At this time, there has not been any clear indication as to whether the flood watch will be extended or if it will be replaced by a flash flood watch. The Passaic Basin will not be able to handle any additional rainfall, let alone flash flooding rains.

On Friday, it is a repeat, but maybe a bit less coverage. The GFS actually has a little more on Friday in the way of convective development than on Thursday. Needless to say, more morning sunshine could set the stage for severe thunderstorm development. Flooding will once again be highly localized, but possible.

The 00z model suite seems to be a bit more aggressive with the Saturday development of convection than in previous model runs. I still think it will be more isolated and also more contained to the east-northeast. It wouldn’t surprise me if it is one of these boardwalk thunderstorm days.

Heavy Rain and T-Storms Moving In

Numerous showers and thunderstorms are moving in from the ocean and will affect portions of our area...especially Southern New Jersey through early this afternoon. Further to the north of this area, a few thunderstorms are developing.

Heavy rainfall, cloud to ground lightning, small hail, and gusty winds may occur with the thunderstorms.

Easily...one half inch to an inch of rain may occur with these storms, adding up to the totals.

Rain Delayed....and this shaves some QPF off

I have not been too pleased this evening with the handling of the storm system on all of the computer models. The modeling has really overdone the precipitation amounts over the past twenty-four hours. The low pressure center is located near Ohio. We are on the northeast side and I clearly see a descending motion of the air or what is called subsidence. This can happen with strong systems and cause precipitation forecast busts. So far it is this descending motion that is causing the precipitation shield to erode as it moves inland from the Atlantic Ocean.

The modeling is continuing to show more widespread showers and a few thunderstorms developing later today. They show an enhancement occurring later this morning and lingering into the evening. At this present time, I think at least an inch of rainfall can be shaved off of the forecast for the Tues-Wed, perhaps as much as two inches. (Some areas have already picked up 2" since Sunday by the way) Therefore, the widespread range will be one to two inches now. There is still going to localized maximized banding of 3 to 6 inches of rain. This is where heavy showers and thunderstorms will train over the same locations. Determining where these bands will develop is quite difficult, especially given the poor handling of the rain on Tuesday. One model set suggests over Delaware and Northeast New Jersey. The Northeast New Jersey being the sweet spot for the event seems to be holding true thus far, although the real argument can be made that Long Island is experiencing the best dynamics. With weak instability, the problem could be the lack of thunderstorm coverage which can quickly yield excessive rainfall as was the case on Sunday and Monday.

Interestingly enough, some areas could see quite a bit of locally torrential rains on Thursday and Friday with thunderstorms, perhaps more than on Wednesday. Instability looks greater with some peaks of sunshine to get more numerous thunderstorm development.

Heavy Rain Moving In

While the afternoon was drier than our computer model guidance had indicated, things are going to turn wet very shortly. Some weak subsidence developed causing the pause in the rain across our region. Radar is indicating a good sized band of heavy showers and thunderstorms that will be moving northeast from the Atlantic Ocean within the next few hours. Some strong thunderstorms with cloud to ground lightning, gusty winds, and torrential rainfall are quite a possibility. Some areas could pick up a quick one to one and one half inches of rain from this round.

Additional bands of thunderstorms and heavy rain showers will be likely through Wednesday. I am expecting more widespread activity on Wednesday than what we observed today.

On Thursday and Friday there will be scattered thunderstorms. With some breaks in the clouds, some greater instability could develop. This means that some scattered severe thunderstorms are possible during these two days, along with the continued threat of locally heavy rainfall.

An aerial flood watch has been continued for Camden, Eastern Monmouth, Gloucester, Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, Somerset, Sussex, Warren, and Western Monmouth Counties. Two to four inches of rain with locally higher amounts are quite possible from through late Wednesday Night. It wouldn’t be surprising to see some extremely local amounts as high six to eight inches over very small areas, but areas that receive several thunderstorms or training of thunderstorms.

Coastal Flood Threat Tonight

A coastal flood watch was issued this morning for all of the New Jersey tidal oceanfronts and riverfronts. The following map indicates when the worst of the coastal flood waters will occur.

Flood Watch Issued

The latest thunderstorm to develop, after the northern round, has been in the Burlington County area. This thunderstorm cluster just keeps redeveloping over the same areas. A very small pocket has picked up one to one and one half inches of rain in less than two hours according to the radar. Similar cells may develop into this evening where small pockets just keep getting hammered. Otherwise, some may see the sun set before cloudiness becomes more pronounced.

An aerial flood watch has been issued for Camden, Eastern Monmouth, Gloucester, Hunterdon, Mercer, Middlesex, Morris, Northwestern Burlington, Somerset, Sussex, Warren, and Western Monmouth Counties. Two to four inches of rain with locally higher amounts are quite possible from Tuesday Morning through late Wednesday Night. It wouldn’t be surprising to see some amounts as high six to eight inches over very small areas, but areas that receive several thunderstorms or training of thunderstorms.

There is about a 100 percent chance of rain and thunderstorms on Tuesday and Wednesday. Gulf of Mexico and Atlantic Moisture will stream in off the ocean. The modeling shows a clear connection occurring. The initial low affecting us right now will weaken and another low will develop around the Carolina coastline. This low will take quite a long time to drift into the Ohio valley.
On Thursday through Saturday, an area of high pressure is going to try to grip the area. However, it appears so weak that it will still permit thunderstorm and shower development. What it will most likely do is limit enough moisture to make the activity more isolated to scattered in nature. With more sunshine expected, we could have an increased chance for some severe weather.

Based on the temperature profiles in the thunderstorm areas today, I did nudge down temperatures a bit in the forecast on the rainiest days.

More thunderstorms today

Thunderstorms have impacted areas from Bordentown and Trenton up into Northern New Jersey. These storms are drifting north-northeast. Very heavy rainfall and cloud to ground lightning is occuring with these thunderstorms. Some poor drainage flooding is more than likely as the storms are slow moving.

Additional scattered thunderstorms may develop elsewhere today in the humid airmass. Heavy rainfall, lightning, and hail is possible...along with gusty winds.

Drenching Showers and Thunderstorms

Showers and thunderstorms are going to impact Western New Jersey for the overnight hours, with an isolated pop-up thunderstorm elsewhere. Otherwise, fog could develop due to the very moist atmosphere and previous rain today in many areas. There could be a few dense pockets of fog.

There is a chance of showers and thunderstorms on Monday. The chance of thunderstorms ranges between 40 and 50 percent, so less than today. It appears the most favorable area will be in the northern half of New Jersey. But a cell could develop virtually anywhere. Once any stratus burns off, some sunshine may develop. It will be warm and humid. A localized flood threat exists with slow moving thunderstorm development…but the coverage is not expected to be widespread. With sunshine, some thunderstorms may once again contain hail and strong wind gusts.

Drenching showers and thunderstorms are a certainty on Tuesday as the moisture train becomes enhanced with new surface low development. Flash flooding is quite possible in some portions of New Jersey. Some areas may see several inches of rain. The chance of rain is near 100%.

Wednesday is once again another day of drenching showers and thunderstorms. Several inches rain may once again occur. At this present time, some creeks and streams with some larger river basins may begin to see some significant flooding. The Raritan River basin is of great concern, but even some of our basins not affected as severely this spring may not be able to take on the amount of rain that is expected. The chance of rain is near 100%.

Two to four inches of rain may fall Tuesday and Wednesday over a widespread area. There could be localized pockets of 4 to 7 inches of rain if the best dynamics play out, especially near terrain influence.

Scattered showers and thunderstorms are forecast to linger for Thursday and Friday. These will be scattered, but with the amount of rain expected prior to Thursday, any additional half inch to an inch of rain in thunderstorms could be very problematic.

Latest severe weather warnings

Click on the doppler radar on the right side of the page and refresh every five minutes or so. The polygon warnings will appearif they are issued.

The latest warning includes Hunterdon and Warren Counties.

Severe Thunderstorms With Potential Large Hail Developing

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR EXTREME NORTH CENTRAL BURLINGTON...EXTREME SOUTHWESTERN
MONMOUTH...SOUTHWESTERN MIDDLESEX...EASTERN MERCER AND SOUTHERN
SOMERSET COUNTIES...

AT 352 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL. THIS STORM WAS LOCATED NEAR WHITE HORSE...OR NEAR
TRENTON...MOVING NORTH AT 25 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
MERCERVILLE-HAMILTON SQUARE BY 405 PM EDT...
WINDSOR BY 410 PM EDT...
EDINBURG BY 415 PM EDT...
LAWRENCEVILLE AND 7 MILES WEST OF HIGHTSTOWN BY 420 PM EDT...
PRINCETON JUNCTION...PRINCETON...PRINCETON NORTH AND KINGSTON BY
430 PM EDT...





THE SEVERE THUNDERSTORM WILL BE NEAR...

TRENTON AROUND 355 PM EDT...
MERCERVILLE-HAMILTON SQUARE AROUND 400 PM EDT...
EDINBURG AND WINDSOR AROUND 410 PM EDT...
LAWRENCEVILLE AROUND 415 PM EDT...

I am noting some weak rotation in this storm. We will see what happens.

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.