wdrag

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

Quick question: Am a little frustrated with MDL not posting MOS since 7/6 and I know NWS wants buy in on the NBM and is ready to discontinue, but myself, I like MOS as an idea of concerns. Is anyone able to acquire the GFS extended statistical guidance for locations in NJ and NYC... (not ALB). Just point me in the right direction. Thanks much, Walt

Onward: Friday: may still have some showers and isolated storms near I80 in NJ through LI and southward. Saturday: May be dry, but modeling still showing small chance isolated shower. Sunday-Monday: Potential nw flow severe event? Still cant get rid of this yet. Modeling has this I90 northward. IF it doesn't occur, then likely renewed heat wave where it doesn't end this week per other posts here...Sunday-Tuesday or Wednesday. Might get to near 97 again in the city- but for now I'm just thinking the rest of this week and allow the models to develop better consensus on short waves-heat and convective thrusts from Sunday the 26th-Wednesday the 29th. 729A/22

Good Wednesday morning everyone, Add graphics etc as you like. After reevaluation using guidance through 09z/22, made no change regarding the topic discussion. I'll add two incomplete graphics for the overnight event which is ongoing (eastward and soon ending) the extreme east portion of our NYC forum (LI,CT). Lightning accumulation graphic was snapped around 514A, and the Radar storm total will continue adding on for LI/CT through 830AM. Today: Modeling is trying to focus a line through virtually all of our area 5-9P, but there could be isolated storms ahead of it this afternoon, and maybe another cluster or two trailing behind the primary line - up till about midnight, especially se NYS and nw NJ. Thursday: wind fields look a little stronger to me for an even better chance of SVR/FF late in the day or evening. Monitor SPC guidance for any upgrade in their thinking. FOG may be a problem the next two afternoons along the south coast of LI, especially Suffolk County. Otherwise heat wave should continue non marine influenced coastal plain next two days. Had .07 on the northern fringe of the southern overnight complex (~1235A). Saw one quarter inch near Patterson, NJ. 614A/22

Fortunately the EC is not known for its convective prowess. However, am a little concerned that Thursday especially may not produce much if the wind at 850 shifts to west or northwest too soon on Thursday. Need to reevaluate Wednesday morning. One day at a time.

Biggest convection both Wednesday and Thursday should be afternoon or evening, depending on where you are. And so... probably okay for a 90 min drive Thursday, but subject to an update Wednesday or even Thursday before 6A. Not sure if anyone noticed, but SPC 13z D1 marginal update has been bulged northward slightly in PA. Thinking that might reflect fairly robust nighttime WAA out there. We'll see how it goes.

After yesterdays long range failure of convection (arrived Sunday night), must look ahead. Modeling, SPC, WPC graphics all suggest opportunity for heavy convection Wednesday-Thursday (22-23). Attached the 6 hr County Average threshold FFG, with hourly guidance even lower amounts. This shows vulnerability in parts of ne NJ and se NYS, plus urban paved environments. SPC Days 1-3 is attached as issued early Tuesday. Also, added a brief 06z/21 GFS snapshot of modeled winds aloft for LGA via Bob Hart's web page (time is in UTC). Note the near 30 kt or greater westerly flow at 500 and 300 MB, showing the idea of enough wind to foster development of SVR organization and strong downdrafts. In these two days, "isolated" storm totals of 4" easily possible with 'general' two-day total amounts of 1/2-2". Warm Air Advection (WAA) instability burst (KI popping into the upper 30s from southwest to northeast by daybreak Wednesday driven by a modeled small 850MB 30 kt jet core in central PA overnight) 'should' develop some briefly heavy showers or a thunderstorm for parts of our NYC forum early Wednesday morning, especially nw NJ/se NYS. After any clusters pass, cloud debris/instability pooling and surface wind shift convergence boundaries will probably be the determinants of when and where heavy convection occurs Wednesday afternoon through Thursday evening. Heaviest should be afternoon-early evening and per modeling, think the bulk of the FF/SVR should be along and north of I80 (far northern NJ, se NYS, CT and LI) but I defer to your assessments, and those of the NWS offices/SPC/WPC, and the modeling from the HRRR and SPC HREF. 734A/21

The future from my perspective: will begin a new two day topic for Wednesday-Thursday and add a couple of graphics by 740A. Next heat-convective event sometime between Sunday afternoon and the middle of next week, but modeling is variable as to which day? and modeling is also variable if indeed another heat wave occurs for NYC between the 26th-29th. I do note the GFS operational has reverted to a potential nw flow event here Sunday (00z/06z 21 cycles), but other global models differ (early or middle of next week). No matter, opportunity for action continues in the overall pattern sometime between Sunday the 26th and Wednesday the 29th.

Looking back the past two days... looks like 97 was the good non-marine influenced max T for the 19th-20th. Even though the HI made it up to near 103-104 in Toms River and possibly parts of LI, overall, I think the max HI was closer to ~100 .. and so from my perspective yesterday-Monday the 20th, did not quite live up to the intense heat that was suggested in some of the modeling (trough too close and so some afternoon lowering of the TD near the city on a westerly surface wind).