E PA/NJ/DE Summer 2026 Obs/Discussion

[JTA66]

It's been a few years since the lawn's been this lush and green in late August.

77F/DP 73F

[ChescoWx]

Most spots dry out a bit today with sun returning we could see a couple showers toward evening especially across southeast parts of the area. A bit less humidity today and especially tomorrow before the chances of showers increase again by Thursday afternoon into the night. The weekend looks to continue shower chances as we continue to erode any drought concerns across the area.

[Chadzachadam]

DPs are still nasty this morning, hanging in the low-mid 70s. should get some relief this evening and tomorrow

[Hurricane Agnes]

I actually picked up some back-built leftovers yesterday for 0.49" total for the day and a 2-day event total of 1.06".

Had a low of 73 and a high of 87.  The dews have been annoying and it's currently 84 with dp 73.

[The Iceman]

5% TOR for extreme SE PA/S NJ/DE. Meso models this morning really liking this area for both strong storms and flash flooding. 06z 3K NAM and 12z HRRR are both nasty later on. NAM with a supercell threat while the HRRR is showing a huge QLCS for this evening. 

https://www.tropicaltidbits.com/analysis/models/nam3km/2026082006/nam3km_mslp_pcpn_frzn_neus_14.png

 

https://www.tropicaltidbits.com/analysis/models/hrrr/2026082012/hrrr_ref_frzn_neus_12.png

[ChescoWx]

We are under a flood watch thru 2am for between 1 to 2 inches of rain and maybe more for some spots that get under a thunderstorm. We will get cooler tomorrow and that will last through the next week with temperatures mainly in the upper 70's to near 80 degrees for high temperatures. We should see nighttime lows back into the 50's by early next week.

[Mikeymac5306]

1 hour ago, The Iceman said:

5% TOR for extreme SE PA/S NJ/DE. Meso models this morning really liking this area for both strong storms and flash flooding. 06z 3K NAM and 12z HRRR are both nasty later on. NAM with a supercell threat while the HRRR is showing a huge QLCS for this evening. 

https://www.tropicaltidbits.com/analysis/models/nam3km/2026082006/nam3km_mslp_pcpn_frzn_neus_14.png

 

https://www.tropicaltidbits.com/analysis/models/hrrr/2026082012/hrrr_ref_frzn_neus_12.png

Unless the sun comes out and bakes this afternoon I don't see it. 

[Chadzachadam]

another case where strong storms are possible in the evening but we get some rain early in the day. wonder if we fail the same way as we have earlier this summer, with too much going on and not enough instability left by the time the storms are expected

[RedSky]

Drought buster incoming

 

[The Iceman]

Mesoscale discussion out

 

Mesoscale Discussion 2052
NWS Storm Prediction Center Norman OK
Aug 20, 2026 17:53Z

Areas affected...parts of southeastern Pennsylvania...central and southern New Jersey...north central and eastern Virginia...much of Delaware and Maryland.

Concerning...Severe potential...Watch likely

Valid 201753Z - 202000Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorms are likely to develop and intensify through 4-6 PM EDT, accompanied by the risk for a couple of tornadoes initially and increasing potential for strong to severe gusts spreading toward coastal areas into early evening.

DISCUSSION...Moderate to strong boundary-layer destabilization is ongoing across much of the northern Mid Atlantic, particularly within seasonably high moisture content air advecting northward through the coastal plain, to the east of deepening (albeit weak) surface troughing to the lee of the Blue Ridge. This is occurring downstream of mid-level troughing, with at least a couple of convectively generated perturbations and belt of augmented westerly flow (30-50 kt in the 700-500 mb layer).

It appears that associated forcing for ascent may increasingly begin to impact a corridor from central Maryland through southeastern Pennsylvania by 20-22Z, if not a bit earlier, supporting the initiation of intensifying thunderstorm development. At least initially, this may include a few evolving supercell structures in the presence of strong deep-layer shear. 

Downstream of a developing wave along a weak low-level baroclinic zone strengthened by differential heating, low-level hodographs are forecast to remain modest to weak. However, they may still be sufficient to contribute to potential for a couple of tornadoes, aided by appreciable near-surface buoyancy developing in associated with insolation, warm advection and dew point increases into the lower 70s F.

Otherwise, at least some upscale growth of initial storms will contribute to increasing potential for damaging surface gusts, with additional thunderstorm development southward along and east of the deeper lee surface troughing.

..Kerr/Smith.. 08/20/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...PHI...AKQ...CTP...LWX...

MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

[Kevin Reilly]

26 minutes ago, The Iceman said:

Mesoscale discussion out

 

Mesoscale Discussion 2052
NWS Storm Prediction Center Norman OK
Aug 20, 2026 17:53Z

Areas affected...parts of southeastern Pennsylvania...central and southern New Jersey...north central and eastern Virginia...much of Delaware and Maryland.

Concerning...Severe potential...Watch likely

Valid 201753Z - 202000Z

Probability of Watch Issuance...80 percent

SUMMARY...Thunderstorms are likely to develop and intensify through 4-6 PM EDT, accompanied by the risk for a couple of tornadoes initially and increasing potential for strong to severe gusts spreading toward coastal areas into early evening.

DISCUSSION...Moderate to strong boundary-layer destabilization is ongoing across much of the northern Mid Atlantic, particularly within seasonably high moisture content air advecting northward through the coastal plain, to the east of deepening (albeit weak) surface troughing to the lee of the Blue Ridge. This is occurring downstream of mid-level troughing, with at least a couple of convectively generated perturbations and belt of augmented westerly flow (30-50 kt in the 700-500 mb layer).

It appears that associated forcing for ascent may increasingly begin to impact a corridor from central Maryland through southeastern Pennsylvania by 20-22Z, if not a bit earlier, supporting the initiation of intensifying thunderstorm development. At least initially, this may include a few evolving supercell structures in the presence of strong deep-layer shear. 

Downstream of a developing wave along a weak low-level baroclinic zone strengthened by differential heating, low-level hodographs are forecast to remain modest to weak. However, they may still be sufficient to contribute to potential for a couple of tornadoes, aided by appreciable near-surface buoyancy developing in associated with insolation, warm advection and dew point increases into the lower 70s F.

Otherwise, at least some upscale growth of initial storms will contribute to increasing potential for damaging surface gusts, with additional thunderstorm development southward along and east of the deeper lee surface troughing.

..Kerr/Smith.. 08/20/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...PHI...AKQ...CTP...LWX...

MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

This seems underway just northeast of Dover Delaware moving NE into Southwestern NJ that is some pretty heavy-duty flooding rains there moving NE.

[Kevin Reilly]

Severe thunderstorm watch moved to a tornado watch SE Pa points South and southeast 

[LVblizzard]

That line coming through Lancaster looks nasty. Wouldn’t be surprised if it leaves a trail of wind damage and even a tornado or two.

[LanghorneSnow]

35 minutes ago, LVblizzard said:

That line coming through Lancaster looks nasty. Wouldn’t be surprised if it leaves a trail of wind damage and even a tornado or two.

Watching ABC, they are stating emergency services have reported a tornado with that storm. I believe that’s what was said.

[Birds~69]

Woohoo....stuff!

[KamuSnow]

There was tornado warning here, but I can't access NWS for some reason. Heavy rain here now, but not much wind.

[Birds~69]

Liking my odds, at least some heavy downpours.

Dark as hell outside....

[Psychguy]

5 minutes ago, KamuSnow said:

There was tornado warning here, but I can't access NWS for some reason. Heavy rain here now, but not much wind.

I think the national weather service is down again because I cannot access it either.

[Birds~69]

8 minutes ago, KamuSnow said:

There was tornado warning here, but I can't access NWS for some reason. Heavy rain here now, but not much wind.

 

[KamuSnow]

11 minutes ago, Psychguy said:

I think the national weather service is down again because I cannot access it either.

 

8 minutes ago, Birds~69 said:

 

Thanks, what the heck? Thanks for the warning Birds, it was pretty easy going here other than heavy rain. 0.75" so far, but it's winding down.

 

[Lady Di]

Had 2 warnings go off  just as i got out of the Acme. Made it home in a little rain. Faired well here.  Reports of trees down in West Grove but it doesnt seem it was a TOR. No sirens or power outages.  Rain has ended now.  

[SouthernNJ]

The best radar signatures for a tornado in our CWA would have been the QLCS moving through Barclay, Queen Anne's county in Maryland into Hartly of Kent county in Delaware.  Then, the QLCS merged with a storm in front of it that produced a sudden, intense wind signature from Wyoming into Dover, which apparently became a tornado right over the city according to NWS reporting of a TDS.

[Chadzachadam]

Should be right in the thick of a severe cell now but the sky lightened up, the wind totally died, and it’s just drizzling. Kind of eerie. Very tropical looking rain so far, tiny drops coming down in waves

[Kevin Reilly]

Had an isolated heavy shower pop up earlier .10" in like 8 minutes guess round 1 at 3:15 pm then partly sunny.

Round Two was a tornado warning picked up .90" wind gusted maybe 25 mph one lightning strike not too impressive overly, but if you looked up clearly see the clouds moving all kinds of different directions so lots of shear with a jet stream right over top.  

Clouds now are just flying eastbound very rapidly winds west gusting to 30 mph currently front through.

 

I am sure there will be some confirmed tornado reports from today's event in the Mount Holly NWS area.

[Kevin Reilly]

Wow Clouds have suddenly switched direction NNE to SSW cold front is through winds gusting out of the NNE 30-40 mph brilliant blue skies appearing almost like a tropical system is leaving.

[JTA66]

1.75”

After a high of 78F, temp is down to 65F. Rain is done here, but still pretty gusty.

[enpawx_observer]

That was insane. PWS got 1.98" for the day. 1.83" of that fell within about 40 minutes. Peak rate was 3.33"/hr (never seen it that high). Never seen my backyard flood like that.

 

Backside winds were also way worse than anything in the storm. Minimal lightning.