wdrag

Northern NJ and se NYS: Dont be surprised at seeing/hearing thunder and or experiencing a brief downpour this afternoon. Already a tiny shower in ne PA at 1025A. I know a few of us up here in Sussex and Orange counties might benefit from a shower, having missed out on the swaths of big time rains this past week. We'll see how it goes. CU bubbling and some decent buildups to the se-s of Wantage NJ.

If dews drop down into the 50s at 20-21z Tuesday, I'll be a bit surprised and for sure would have to write off Tuesday afternoon convection (delaying til night or not at all). NAM 12K for 18z has what appears to me, a solid chance of dews at least 65 at KEWR at 20z (extrapolating FWN 18z Sussex dew to EWR at 20z.) My guess if dews are down into the 50s during mid Tuesday afternoon, the front would have accelerated quite a bit. Maybe a safe 20z temp forecast for 20z/Tuesday is 95/65, but with uncertainty regarding cloud debris?? just my 2c. This will be an interesting forecast contest between 00z/25 EC HI res, vs EC/GFS/NAM consensus 10F warmer TD. {misunderstood on Euro posts above... they look reasonable. Thought these were referencing Tue 50s TD. My bad---just was too hasty on my part. Walt Sunday 7/26 958A}

Hi! Heat wave looks halfway decent, beginning today a few spots inland from NYC and culminating in potential near 97F Mon-Tue. Does it break with weak cool frontal convection Tuesday, or continue beyond...albeit marginally? Strong cool frontal sewd moving convection still looks good to me (not overwhelmingly good) for Tuesday (PWAT 2", KI upper 30s, cooler wedge at 500MB with marginally good enough 500-300mb winds) , but i see some modeling with a delay til possibly Wednesday, and even one model suggesting dying convection arrives Monday night (though I think capped by rather warm 500mb temps of -4C and so convection in se NYS/CT unlikely Monday night). My choice for now is Tuesday afternoon-evening. No topic yet till am more assured timing is going to focus maximum potential 2P-10P. Keeps all the discussion right here. Have a good weekend. 613A/25

My last on this... thinking of when to start Tuesday topic-it may be tomorrow-timing is a big part of summer convection, but last night was different...I think in part due to all the low level convergence encouraging Friday morning's big storms (light northerly surface winds to the north of the boundary and light south-southwest to the south). I don't want to start Tuesdays topic so early that it weakens to standard run of the mill scattered shower/thunderstorm due to poor timing. This weakening could happen even if the topic is delayed til Monday morning. Summary: here's the RFC 3 day multisensor totals... from what I can tell, at least 4" in this conservative assessment. OKX RADARSCOPE Digital storm total for the period Tuesday evening to about 2PM today, showing 5-6" in yellow-red. There might be some hail contamination that falsely inflated the precip totals a bit. I'm interested in ground truth totals for the entire 60-72 hours of 4+ inches. If none additional are posted, that is fine. We have to move forward. Thanks. 225P/24

Well done!!

Today: sent an update to the two day SVR/FF topic. Big rains likely today for parts of NJ/LI (maybe even NYC) in leftover PWAT/subtle convergence on the trough. Suspect will require 1 or 2 FFW's. best bet I think is between I78-I195 Tomorrow: still could see a shower or thunderstorm in NJ/NYC, but lower pwat. Leftover CAPE part of the problem. Heat wave probable Sun-Tue and may begin Saturday and continue into Wednesday. 97 the worst on Monday-Tuesday and probably closer to 95F. (all non-marine influenced coastal plain, especially Hud Valley/I95 corridor). HI max probably to 100-103, either or both Mon-Tue and inclusive of eastern LI. Next topic: not started for several days until more certainty. Tuesday convection. Ingredients seem in place. Approaching southeastward moving cold front, just enough wind aloft, CAPE/KI. Timing uncertain which may rob the potency (predawn?), even possible that dying strong thunderstorms arrive early Monday night. Fwiw... Hanna may contribute a small amount to the 2" PWAT Tuesday. (the nw flow event thought to occur Sunday ish in our area a few days ago, seems destined for Maine Sunday with only CAPE missing there...still something substantive should be traversing far Northern New England Sunday or Sunday night). 657A/24

It ain't over for FF (I don't think). While this topic has basically ended. More intense rainfall of 1-3" in 1-2 hour period expected somewhere extreme s coast LI or between I78 and I195 in NJ today, especially this morning. PWAT still 1.9", trough nearby with subtle convergence, leftover CAPE. Attaching a few maps. While a bust (nada) for parts of the area yesterday, I consider this not a bust for sw CT, NJ- just sw of NYC. We now have many 3-4.5" report totals past 60 hours (Tue night lead WAA, plus Wednesday, plus Thursday up to 5AM). New Brunswick NJ RU climate site 4.25", Pequest at least 3.64". I'll add some data from just midnight onward this morning (Weather Underground)-many 2-3.5". PHI added a report of over 4" early this morning in the warned (SVR and FF) area. 630A/24

Not over. Iso SVR possible thru the night...not probable but frontal boundary, PWAT 1.9", 850 vorticity with trough coming sewd, RRQ 500mb jet and activity not yet waning very much in PA/CT (esp CT where its not supposed to be doing much in the models). I think the NAM12K has it right and while I could be wrong, I am looking for showers, iso thunderstorms to expand eastward along I80-LI and persist into the 10AM Friday hour. If I'm wrong, I'm possibly just a touch too far north. I saw minor svr late this aftn toward Red Bank NJ, possibly now in sw CT, and Pequest NJ area already past 3.6" for the entire forecast period. Will try to gather a few more reports in the morning thru 12z only.

Review: Appears to me 2 bands of big storms going to move east southeast through portions of the NYC forum between now and midnight, with isolated heavy showers ahead of and in between. Of possibly greater interest to me for widespread heavy rain is just north of the frontal boundary between 2AM and 10AM Friday (LI-I80 southward). Line in MA has been SPC watched. That may extend back into ne PA soon? The line further back in central NYS may be bigger deal (warning out recently)...that one is closer to the wind shift. Not quite as ripe ahead of the lines as yesterday but would not give up yet... Have plenty of instability, moisture and lift arriving this evening. (see what's happening over L Erie in cloud animation at 1830z). For Friday morning: there could be quite a band of heavy rain just north of boundary if the wind turns light north or northeast by dawn Friday...accentuating sublet lift of a wet airmass. Not severe but rainfall of over 1" in 6 hours possible. Not guaranteeing but that has been cued by the UK and less robustly in a few other models. Just have to wait this out a little more and watch upstream development, surface convergence and dew point pooling near 74F for the prefrontal few SVR or FF. I think there will be some action to discuss in our area by 6PM. 240P/23

SVR-FF potential continues... a little more wind available aloft, but not sure it will be quite as unstable, in part due to cloud cover. My guess is more FF, than SVR with bulk of east-southeastward moving big producers 4P-mid. Might have a few showers around this morning. Please follow SPC/NWS local discussions-statements and your own expertise. I'll post the updated 6hr COUNTYWIDE average threshold now. Then when time permits midday, will revisit the mesoscale and see if I can figure out a probable most favorable area for FF (2-4") amounts between Noon-midnight in a few spots. If it repeats I80-I78, then a bit bigger problem will ensue. Just don't know the details. (saw the very wet UK overnight but don't know what to make of it). Off line 630A to possibly as late as 1P. 618A/23

Outlook:Have dropped NW flow event here for Sat night-Sunday night, still possible in Maine? Our next big convective event probably Tuesday the 28th or Wednesday the 29th (tho may see a hint of convection late Monday,). For now thinking Tuesday. That event probably ends another 3+ day heat wave here (for sure Sunday-Tuesday), with 97F possible Mon or Tue along with HI ~100. Not expecting 100 air temp. Heat wave probably begins part of non marine influenced area this Saturday the 25th. 6A/23

From yawners to big barkers, the 2PM-9PM svr and heavy rain bands soon will be done, with widely scattered possibly briefly heavy showers overnight. Tomorrow is another day but essentially no change to earlier thinking. Have added a few graphics: Won't be surprised at seeing a 3.5-4.5" rain report come in from near Liberty Township in northwest NJ, just s of I80. Otherwise posted a couple of radar storm total graphics. OKX includes last night while DIX is only this afternoon-evening. See the one early storm track on DIX (Brodheadsville-Scotrun-Montague storm) near the nw tip of NJ. Also, Rutgers climate totals for today only. Have seen numerous 2+ inch amounts on weather underground personal weather stations and a couple between 3.5-4.5" So we'll await more data tomorrow morning. Also a crude map of reports as sent by the NWS by 830PM. Finally a sampling of customer (household meter) power outages in the northeast as of about 830PM.

Rest of today and Thursday: No change in the ~630AM update and topic. SVR reports will continue to accumulate (retrieved from early storms passage). Also I think you're going to see a few 3-4" amounts near Hackettstown-Great Meadows NJ. Flooding: I'll post an updated FFG map tomorrow. You already see the SPC D2 svr on-line, for the NY forum. I'll try to get this all out by 630A Thursday. Note: We could see 2-4" of rain in a narrow band somewhere in N Jersey or se NYS tomorrow... for now the SPC HREF has it toward Ocean County (MAX amount). In any case, tomorrow's activity may continue lively for heavy rain past midnight tomorrow night. Regarding the 3" near Mansfield NJ now... fail total by tomorrow night may be ~ 4". Selfdom do heavy thunderstorms traverse the exact same path two days in a row... but we'll see.

Pequest NJ (RU clim site) 3.02" so far, last night through now.

Not the versions after around 12z... but prior to that NAM3k, HRRR etc were pretty robust on a 5-9P line traversing virtually all of our area. This happens sometimes, the models see something for several cycles well in advance, then lose it in shorter lead time (not good and inconsistent). However, when 12z runs didn't init well for 16z radar, we had a hint the models had problems. Anyway a number of 1.5-2.5" reports today from near Mount Olive Township to near Glen Gardner. Probably going to be some road travel problems by 745PM in more eastern parts of paved regions in NJ due to excessive short term rainfall. Also noting more and more severe reports from the mid afternoon ne PA complex.

fwiw at 540P...the line developing northeastward (northern extent so far) toward Wantage in far nw NJ is the real deal... very dark south and southwest. Can see nice building CU/CB at north end of the line and we should be assured of doubling the .01 we received around 315P. Also saw the two hail reports with the 310-320P cells in far nw Nj and they sort of looked like hailers on my visuals (so much light showing through the falling precip). Any way, this 540 PM line should be more productive for the NYC forum except maybe Middletown NY area. Enjoy whatever you receive.

Thanks... see others as well. NJwx85 just commented. By the way, 2 reports of damage now in the Pike County storm. Think I'll leave this play out through 9P and see what happens. I see other warnings by PHI now so...slowly growing. Walt 357P/22

Just an observation... the cell missing most of southern Wantage NJ with just TRW- so far, is rolling thunder. Not the cracks that startle. CB top sort of look capped, lots of light coming in from the south through the rain, and the cu ahead of it are frayed. Hope a line develops behind this Sussex County NJ loner. Just doesn't seem like everything is ready to erupt up here. May be it will go further east, or develop toward 5 or 6P. Noticed no reports yet to the NWS.

VIL on the ne PA cell only briefly mid 40s thru 2P while the one near York Pa looked briefly like a 70vil (SVR, I think hail for sure somewhere in that one). The ne PA storm might have suprising injury causing lightning the way its spread "behind" the primary cells and it looks like G winds near 35 kt with hail from what I can tell. Bottom line, storms are organizing for the SPC MCD area. Probably off line til 4ish.

SPC at 145PM EDT. No guarantee for for me in Wantage we may miss the first batch developing east northeast from vcnty Brodheadsville in ne PA. storm looks impressive at 153P. This should be the batch to watch. again, no guarantees. Hope this works out well. https://www.spc.noaa.gov/products/md/md1313.html Mesoscale Discussion 1313 NWS Storm Prediction Center Norman OK 1245 PM CDT Wed Jul 22 2020 Areas affected...portions of eastern PA...NJ...southern NY and southern New England Concerning...Severe potential...Watch possible Valid 221745Z - 221945Z Probability of Watch Issuance...60 percent SUMMARY...Scattered thunderstorms will increase in coverage and intensity through the afternoon. Strong, locally damaging gusts will be possible with these storms into this evening. DISCUSSION...A broad area of deepening cumulus continues to develop across portions of eastern PA/NJ northeastward into southern New England ahead of a shortwave vorticity max. At the surface, a warm front extends from central NY east/southeast into CT/RI. South of the front, surface dewpoints are mainly in the 70s F and strong heating has allowed temperatures to warm into the mid to upper 80s F. As a result, a tongue of MLCAPE from 500-1500 J/kg resides from eastern PA and NJ northward into southern NY and western CT. The warm front should progress northward a bit more through the afternoon and at least weak destabilization is expected as far north as southern VT/NH into western/central MA. In addition to weak to moderate instability, moderate deep shear resides over the region, and effective bulk shear around 35-45 kt should overspread the entire MCD area by late afternoon. Some uncertainty with regards to convection initiation remains, largely due to weak forcing across the area. A vorticity max further east near Lakes Erie/Ontario should spread eastward with time, but initial convective development may be largely driven by diurnal processes, especially over southern portions of the MCD area from far southern NY/Long Island southward into NJ. Nevertheless, the overall environment should support organized cells and clusters, once they develop. Midlevel lapse rates will remain modest, but strong heating has resulted in steep low level lapse rates south of the warm front, and PW values greater than 1.75 inches will further aid in strong downburst potential. While timing of convection remains a bit uncertainty, at least sporadic instances of severe gusts and locally damaging winds are expected into the evening hours, and a watch may be needed this afternoon, within the next few hours. ..Leitman/Hart.. 07/22/2020

Also, fwiw... the primary line had previously been slated by primary USA guidance in the 5-9P slot for our area. Am not too worried, yet. New cell near ABE and it looks to me like central PA activity is developing enewd. I may be off line for a couple of hours. Ride it out a little while longer and follow NWS/SPC discussions and your own observations of surface convergence, and cu field pooling-development. Thanks.

Very helpful to know gentlemen... I tried the link provided this morning, a couple of days ago and no luck. So, am glad it just wasn't my own operator error. That said...also helpful to know NBE performance and... good thing that it improved on MEX because we're in a statistically persistent pattern of warmer than climate normal. I'd be really disturbed if NBE didn't improve on MEX. Also, had seen EC MOS in its more primative non gridded stage prior to March 2018 retirement, within NWS. Sharing International model guidance is relationships, benefits to countries etc. NWS I think incorporates the MOS into some of their products, if forecasters elect to init with the base blended statistical data.

Quickly reevaluated with latest guidance (RGEM, GFS, NAM, NAM3K HRRR and last nights ARW 1 and 2). Please point out what I'm missing. I could be missing something. Otherwise, I'm seeing poor 12z model radar init for 16z. and wherever I see it has something, the development is northeast toward virtually all of our NYC forum by late afternoon. 16z S wind IPT area with dew points in the 70s in e PA/NJ/NY, plus cu fields from ne PA into nw NJ suggest to me to look for further developement northeastward in this cu field and eventual big storms by 5P. I could be wrong... so no guarantee but that's what I see from a quick glance at surface, cu fields and modeling. Big storm suggestion is the anvil blowoff in the little cell vicinity York PA past 45 min.

TCU w and ne of Wantage around 1220... tiny cells just e and ne of NYC. Line growing central PA. Will review. 86/73 here in Wantage 1230P.

Thanks UOFMIAMI and BLUEWAVE for your replies. Couldn't get the MOS to work earlier, but now good with your link and also hadn't seen the transition announcement. Thanks to you both. I'll be checking the NBM against GFS MEX MOS in some critical situations. offline til about 1230P. Walt 1029A/22