wdrag

Wantage NJ 0.54" so far 5A-8A. Definitely valuable rainfall.

Good Wednesday morning all: welcomed rains here in far nw NJ since 5A..so far 0.37". No topic on the SPC D1-2 marginal risks parts of our area next two days: You're welcome to add this as a topic. Aside from a wet Wednesday morning in far nw NJ/se NYS /CT, I see a band or two of heavy showers/tstms sometime after dark both this evening and Thu evening, but EC modeled CAPE continues meager in our area; so if SVR makes it into our forum area, my expectation is only a couple of reports, mainly western/central NJ. Still time to add asa topic if model favorability improves. On next week: I added a 00z/2 NAEFS prob of 2" or more of the entire period. This is a decent ~30% chance, a week in advance. EPS only has near normal anomaly next week while the GEFS is definitely wetter than normal. This far in advance, at least our trough-ridge position is favorable for qpf... but the targeted, repeat episodes is uncertain and should be focused along the quasi-stationary boundary, and upslope regions- which could be a little to our west? 720A/2

Modeling via the ensembles continues to suggest next week (7-14), will provide us near normal qpf, maybe above normal interior a below eastern LI? Several events and somewhat depends on position of a possible quasi-stationary front the eastern seaboard. This as per several graphics posted from various members the past two days. One thing that from my perspective will be less evident than in summer... heavy convection, due to shorter-cooler days. So, I think we're going to need a boundary to help us out, aside from the upslope interior mountain ridges. If it ends up the flow is southerly, rather than southeasterly, then we have more opportunity for LI/CT to see some decent showers from the lift of the southerly flow over the landmass. Lots of unknowns. Regarding the SPC depicted D3 marginal severe for our area this Thursday... holding off as a topic at this time. It is late in the season, and the EC does not have enough CAPE-KI, in my opinion, til evening. The winds aloft - modeled and discussed by SPC will be in place, but the CAPE-KI are slower to arrive in our forum than the 06z/1 GFS models. Otherwise...seems like periods of showers-drizzle the next two days (today-Wednesday). 657A/1

Saw the several posts today on the longer range: I agree... looks interesting. Adding the NAEFS D8-14... thats' been consistent for a couple of days now... how it evolves is unknown (pieces for northern stream, or maybe cutoff something down in TN?) What this flags for me is a southerly component and potential for increased rainfall. Maybe most of it will be Apps west? I'll guess maybe a little closer to normal for most of our area, than what we've experienced since Isaias. This outlook would be for September - week two.

So in summary, I'm pretty sure tropical moisture made it at least into the extreme southern part of our NYC forum, per attached radar and CoCoRAHS rainfall Fri-Sat (3"+ extreme south part). The EC and UK were far too strong on the remnant Laura holding together across the Apps and may have contributed to some of the high bias in forecasting the resultant rainfall (disappointment for many of us I78 northward). Our part of Wantage NJ had less than 1/2", even including the 27th! I do think it was worthwhile to follow Laura's potential impact on our area, appreciating model guidance in its various deficiencies and strengths. We do know there were flood warnings near PHL and in the Delmarva for this storm...fairly close but not close enough. Our

Hi! Here is a very good summary of supercell path through CT by Dr Anton Seimon with supporting guidance etc from NBC Met Ryan Hanrahan. I post this because this event, for late August was pretty substantial and especially for parts of CT. SPC did a good job capturing a fairly high end event. This is my last on the 27th... but I wanted you to appreciate the discussion and additional information. The appended images would need to be inserted into the discussion below... but if you take a moment, you can see some value added. B Back on Thursday, while many on this list were tracking the progress of TC Laura through Louisiana, a strong supercell thunderstorm tracked from south of Albany southeastward across Connecticut to Long Island Sound. Major damage was registered in several towns in Connecticut, and the NWS has confirmed an EF-1 tornado track with an 18-km path, and more widespread damage along a broader path from a series of microbursts. The severe weather potential was amply recognized in SPC Outlooks and Discussions leading up to the event, and the localization of the most severe threat to a narrow corridor was especially well represented in guidance from convection-allowing NAM operational runs. Here is one NAM guidance product, courtesy of the College of DuPage, from the 18 UTC run on 26 August; the most severe damage occurred close to 20 UTC (4 pm EDT), so 26 hours after model initialization. The 12 UTC/27th run 18 hours later maintained this high-end supercell scenario in time and place. The o The overall setup of a supercell tracking along a surface warm frontal boundary under seasonally strong northwest flow has striking similarities to an even stronger event from 10 July 1989, which produced a 100+km track of forest blowdown in Connecticut culminating in an F4 tornado at Hamden. https://en.wikipedia.org/wiki/1989_Northeastern_United_States_tornado_outbreak The NBC meteorologist Ryan Hanrahan offered a meteorological overview of the setup on Thursday: https://www.nbcconnecticut.com/weather-news/on-ryans-radar/august-27-tornado-event/2325826/ There are some remarkable images and video sequences that have been posted on the Internet. Ryan’s Twitter feed provides a good collection, including the screen-grabbed image below of the advancing mesocyclone as it reached Long Island Sound at Madison. Be sure to view this dash cam video from a driver caught in the rain-wrapped mesocyclone in North Branford at 4:10 pm EDT: Be sure to view this dash cam video from a driver caught in the rain-wrapped mesocyclone in North Branford at 4:10 pm EDT: https://twitter.com/Eweather13/status/1299326159423930370 The National Weather Service office at Brookhaven NY (OKX) surveyed the damage yesterday and posted findings on the tornado and microburst damage. https://nwschat.weather.gov/p.php?pid=202008290246-KOKX-NOUS41-PNSOKX There is ample evidence from KOKX radar Doppler velocity scans that the wind field in southwest quadrant of the mesocyclone circulation, augmented in a ground-relative sense by the storm’s rapid southeast motion reached hurricane force along an axis several km wide. The Radarscope screen grab below from 7-8 minutes after the assessed tornado dissipation time shows a conventional signature of a high-precipitation supercell with inbound pixel values of 42 m/s: this corresponds very closely in time and space with the video linked above.

Just saw the HRRR peel the bow echo southeast toward PHL instead of to near Toms River late today. So I could be mistaken on my previous post. I did see EC parameters and it looks quite robust Saturday, even predawn, for big rainfall producing thunderstorms...possibly in several bands...not only Ocean County to eastern LI, but maybe something near or just nw of EWR-HVN. EC dewpoints rise to the mid 70s midday Saturday.

Early CoCoRAHS reports. Digital storm totals were over 3", nearly 4" in a part of CT. Included one sample WXUNDERGROUND. Graphic of yesterdays svr wx reports. 825A/28

Active late afternoon ahead for the forum and pretty sure severe in NJ and possibly LI with bands of good sized rains of 2-3 possible If there is overlap with yesterday’s 1-3 rains in parts of our CT/se NYS forum, it would be there later this evening or overnite. HRDPS looks pretty good to me. Could be a big bow echo later this afternoon in NJ? Saturday: Please see WPC and SPC D2 QPF./ SVR 716A28

Svr reports 130-515P as rcd and posted by the NWS, so far in our forum area.

Past 3 hrs severe reports SO FAR, as received and posted by the NWS. 125-425P/27

Rainfall reports of 1/2-1.9 inches so far parts of se NYS into s central CT in our forum area. A nice start... going to be interesting on some of these numbers by 03Z/Sunday...esp CT, se NYS and maybe LI. UKMET extreme of 7" may not be far off the mark...just don't know where yet. Events have to overlap. Should be a few interesting numbers of 2+" by midnight tonight.

Time on family wedding vacation for a quick post: Am adding some HRRR gust forecast data for now through 10P, then for Friday afternoon. Max Gusts..see 40-50kt via legend. Also adding 80m wind forecast for CT-LI area late today to show the backdoor cold front-thunderstorm aided southward progression. This front could nix svr risk for LI/CT tomorrow afternoon but NJ I think has a pretty decent chance of SVR Fri afternoon and maybe the SPC D2 risk may be advance northward there in tomorrows update. In the meantime, expecting lots of svr for NYC forum through 9PM today.. even e LI where best chance of rotation is modeled in the HRRR. PWAT up to 2". Lowest chance svr through this eve, I think is Ocean-Mercer I195 area. Fri: potent on the warm side of the front as exampled in some of the modeling for tomorrow. Fri night: difficult to see this as a quiet night. KI very high at night. Could be a few 1-3" clusters..PWAT 2"+ Sat: while Laura goes out somewhere through S VA-DE... there should be more convection along the cold front!

Adding more: 12z/26 UK is north and pretty wet. Unsure whether even half of these values will be realized. You'll know how we're doing by midnight Thursday night.

Throwing this out there: I took a little longer look at origination of parcels this morning that arrive NYC via 00z/26 USA Models (NAM, GFS) and this will be interesting... dewpoints in the mid 70s FL-GA-MS etc. If we get mid 70s dew points... pockets could be wetter than 3" in parts of our NYC forum in the 24 hours ending midnight Saturday night. Also, not sure how long this will last but 00z/26 EC EPS is trending wetter. Attached widespread 24 hr 1". Meanwhile, GEFS is/was still split north and south of us. Also looking at the 06z GEFS 500mb... from what I can tell Laura may not move due east thru southern VA per multiple tracks and ICON, UK) but instead start turning toward 070 degrees per 500MB seemingly backing ahead of the next Great Lakes trough. I am not writing off a closer pass (DE) for Laura's center if it indeed holds off til Saturday evening. What that might mean up here, am unsure.

I haven't looked too close.... Other's may want to chime in. SPC D2 outlook update should be out by 2P. I'd say there is chance of a TOR, provided a super cell forms. See SPC D2 and others comments including NWS offices. Thank you. 142P/26

Yes, I think everything is pointing to an active period. Thanks for the lightning post

Extracted from the tropical topic: A period of WAA showers/elevated isolated thunderstorms early Thursday north of I78 for much of the forum, then the potential nw flow severe weather event sometime between 4P and midnight late Thursday. KI 35-40 late Thursday and PWAT temporarily up to at least 1.8. Plenty of wind aloft and see SPC. Should be steamy in NYC Thu afternoon (HI 95-100?) 827A/26

Good Wednesday morning everyone, I don't see much change from yesterday's early morning expectations. Please follow SPC discussions/graphics of SVR for both Thursday and Saturday in our area, as well as NHC discussions-tracks and of course, local NWS office discussions-statements. It appears that the remnant surface center of Laura will track through southern VA or extreme northern NC Saturday and zip northeast from there. That means the strongest gusts of 40 to possibly 50 kt in squalls will occur south of NYC fortum area...probably within 70 miles of ~ the southern semicircle of Laura's passage. Therefore only an indirect influence on our area weather in terms of jet dynamics (hybrid Laura-possibly still a TS per 5AM/26 Wednesday NHC discussion) and moisture. PWAT increases to ~2" Saturday (trajectory models from the NAM and GFS ending Saturday show a vast low level moist influx ending up at 500 meters at LGA on Saturday. To get there... A period of WAA showers/elevated isolated thunderstorms early Thursday north of I78 for much of the forum, then the potential nw flow severe weather event sometime between 4P and midnight late Thursday. KI 35-40 late Thursday and PWAT temporarily up to at least 1.8. Plenty of wind aloft and see SPC. Should be steamy in NYC Thu afternoon (HI 95-100?) Friday evening-night---a period of showers and thunderstorms possible in once again WAA, well in advance of Laura. If there is a well defined wind shift boundary in our area...this could light up as a 3-6 hour period of heavy rain. Right now, an unknown and not something to count on. HI near 95? Saturday afternoon-night: PWAT2", northern fringe of Lauras moisture and a cold front should trigger a severe weather event in parts of the northeast, along with a couple pockets of heavy rain. How much severe here, if any... just follow the evolution. HI 95-100 but max value dependent on cloud cover, especially associated w Laura. I don't want to overpromise: WPC's early morning 5 day totals are generally 3/4-1.5" in our area...nothing to write home about, but potential exists for 3" totals somewhere. It appears to me the risk of heaviest totals, whereever, first is CT, followed by LI, then se NYS, with NJ maybe lagging on the lower risk for any spotty 3" totals. I may not be able to post very much until Saturday evening per the next several days of family celebrations. Appended trajectory data, SPC D2 and 4 outlooks, and the NAEFS mean pressure pattern for Saturday evening (primary low in New England but think that there should be another low somewhere near ORF?) 540A/26

So the wrap, as of 9PM tonight... not much to fill the thread, very tiny areas Sunday-Monday. A bit better today in the SPC slight risk but imo, this didn't do justice to the potential for a couple of reasons. 1) generally w-nw flow in the boundary layer which tends to be a drying downslope flow. 2) I just don't think there was enough convergence at the surface... (wsw wind ahead of cfp vs nw behind). However, we got something. The HRDPS generally did best. The SPC HREF had an idea but too far west in NJ. The HRRR after 10z/25 was not very helpful (too little), except it spoke of uncertainty. The 00z-12z/25 GFS was not very good after 18z/25... just didn't have a clue past the Appalachians. GGEM and UK were ok in a meager sense and EC had something. You're welcome to add perspective. otherwise, that was my last attempt at this thread. 927P/25 attached Storm reports and the OKX STP...one strong long continuous cell was the Port Jervis-High Point toward NYC along the NJ/NYS border... stands out a bit in the STP.

I see several reports of Snr in se NYS so far. At least something happened. Looks like NYC done around 7p per reality and the too fast 12zspc href a lns hrdps. GFS terrible for the 18z-00z modeling. Whew. One thing. Bases seem a little high so nice looking from the backside here in nW NJ but nw flow drying must be a negative factor on storm size so far

My last for a little while I think. Modeling is maybe an hr fast... HRRR still looks too dry but a consideration. 12z RDPS and SPC HREF appear best to me and certainly the GFS is not doing well after 18z. Still a little worried about all the w-nw low lvl flow and lack of well defined sfc convergence. 419P.

Possible. I’m unable to devote much time right now to weather. Please follow reality, NWS offices statements reports and the latest SPC MD which covers NJ as 80% likelihood of a watch.

Just seems marginal to me so far. Has to happen by 545 in NYC of anything substantial

Your decision. Sorry. Not at home now. So far storms are pretty small. There could larger storms by Sat night? Travel carefully