wdrag

Tonight: Rapidly developing convection in northern PA at 525PM may pass mostly across PA/NJ, especially just s of I80 meaning NYC may miss out on 1/2-1/2" tonight (& hail) and escape with much less. I saw the 18z/13 NAM w large qpf in NYC, but a little concerned the PA action will hug the greatest instability. Nevertheless, if it looks impressive at 830P for SVR, I may add a thread for reports. Tuesday-Saturday: ENS are getting a little wetter with the NAEFS showing an approximately 40% chance of 1" NYC-LI by Saturday night. EPS has definitely become wetter, in part by what I think is an evolving upper low s of LI (well south of anomalously warm heights near the Canadian border); and possibly a little northward ingest of Nicholas moisture as witnessed via the EPS above normal corridor newd from TEXAS thru the OHIO valley to I80 in the Northeast. Even the pattern toward the 28th-30th is taking on an interesting look as tropical members head north off the east coast.

No threads despite SPC D1 attached, and what appears to me a piece of Nicholas PW leaking out up into our area toward the 18th. This thread will suffice, if anything significant happens. After the 19th, doesn't look promising for a big rain that till the 29th-30th, but lots can change by then. For now, it would be nice if we do get some convection early Tuesday morning for starters. We're also on the se edge for Wednesday SPC D3... will take one day at a time. While some of the parameters are favorable for later tonight, I'll just accept decent storms in the Scranton - NYC slot as useful. Some of the 00z/13 modeling has at least temporarily backed off on an event for tonight. SPC D1 and discussion attached below, as well as the 00z/13 SPC HREF mean qpf and MAX axis qpf.. Would love to see this mean correct... confidence less than ideal. 623AM edit: I see the 06z GFS is back on board tonight. Nice.

Reviewing 12z/12 model guidance: Nicholas moisture has a chance here toward the 17th-18th if it doesn't get stuck in Texas, or swept to our north. SPC this afternoon has upgraded to slight risk Tuesday, which may happen early in the day and again at night per potential clusters of thunderstorms and fairly strong nw-w flow aloft, and TT 52-57. And the mid Atlantic coastal low option still is an option here, if it doesn't turn east out to sea next weekend? No threads, just too much model disagreement.

927AM edit additional impressions: Just reviewed data in more details. 1) 06z GEFS starting to show more interest for me regarding a tucked in rain producing low for the mid Atlantic coast 15-17th. Members starting to pique my interest. Also a load of TC reflections after the 23rd moving n or nw in the w-central Atlc. These could all recurve too far east. My interest will grow much further if we can start seeing GMEX (w of 75W TC's). This going to be interesting as anomalously warm heights build over the se quarter of Canada the next 10 days (to me implies slower movement as steering flow decreases in the eastern USA) 2) SVR threat: EC has a pretty decent nw flow svr signal for Mon afternoon-night and I'm a believer in any model showing bullseye stripe of 1/4" plus in PA/NJ/LI Monday or Tuesday as Cape also increases, with TT in the low 50s and winds aloft greater than 35 kt.

Hope Don is right above: No event threads yet...just too much uncertainty in my mind, when. The past two cycles of the op GFS (9/12 versions) look a little unrealistic to me when looking toward the 20th and seeing it model a 1030'sMB high down our way into New England. Doesn't seem normal for the pattern (too strong a high). SPC has a marginal risk here Monday the 13th. Will rereview next 24 hours but no thread. The Texas coast (likely in my mind) TC Nicholas has some opportunity for moisture to escape Texas and head our way late this week?? but nothing clear cut for me. EPS and GEFS are not yet showing above normal qpf here before the 28th, which is tempering my enthusiasm a bit, despite pattern evolution. I always consider the overall ensemble modeling, especially beyond 48 hours. Will check back again early Monday. Enjoy these days.

Posting rainfall specific to NYC in the CP thread next 8 days. May be gin a thread for a tropical system of sorts sometime Sunday. I need to more thoroughly review,

So, there should be showers in the NYC subforum as early as later Sunday (probably later Monday into early Tuesday and possibly again 15/16th. I'd like to see NYC get between 0.1-0.2 the 13th-14th and a quarter inch or more the 15th-16th. Then thereafter, we see what evolves from the cyclically favorable GFS and GGEM op cycle for tropical WAA after the 17th. Timing and organized trop system unknown. No thread yet on tropical system (or remnant -post TC) but re-reviewing early Sunday and more thoroughly.

Yes, definitely a little cooler than I expected the past 4 days. Not starting any new threads yet. SPC has northern part of forum in Marginal Risk Sunday (my guess is a shower or thunderstorm Sunday night) and possible thunder on Monday (again late Monday or Monday night). Pair of tropical PWATS head north next week from near 30N (FL Atlantic coast to Gulf Coast) and could mean some larger scale rain action later next week but far too early for me to thread, confidently. CPC has odds favoring normal, or possibly above normal qpf next couple of weeks.

What happened: via CoCoRaHs

There should be showers in the NYC subforum later 12 into early 14 and possibly again 15/16th. After that pattern should become favorable fir tropical WAA after the 17th. Timing and organized trop system unknown. Trod has a tendency to back up to Miss Valley as I see it in the ensembles by D10-15. That should allow WAR to strengthen. Lots of unknowns. Latest CPC D6-14 has odds favoring AN QPF. Unknowns but pattern says it’s possible.

All good on Don’s post. 7.51 as of 8PM.

CP now up to 7.46 or more

CP makes it to 7.40 so far with .15!at 1030

Quick snapshot of what has happened. incomplete data. Sharpening trough approaching from the west has grabbed a little of the NC coast PW and slow movement of trough presents rain problems for the I95 corridor eastward today.

Wantage NJ-this part of nw NJ 1.06 so far. Complex evolution but NYC/w CT should finally get some rain today, bigger amounts probably eastern LI CT River. 06z NAM must be a little too wound up to the west. late HRRR is decent. Wont be able to comment much til its all over. Will add 2 day COCoRAHS late Fri. The HRRR STP/max 2-5KM UPDRAFT picked out the svr/heaviest rain axis pretty nicely for e central PA/ALB areas.

Sept: last half seems to be setting up ever-so-slowly for plenty of rain here. Ridging developing northern tier, while a weakness evolves Gulf States (wet). I see NYC yesterday only a NORMAL day. Might happen again Friday-Sat, but otherwise me it looks like the warmer than normal pattern here should continue through at least the 23rd.

This may be of interest and may support NWS actions late today, tonight. Take a look. Rainfall needed to trigger FFW in 1 and 3 hour increments. I may off line til 5P. Have a day and add on as guidance-data warrant. Thank you.

did read this prior to post. I still believe I'm correct we have report seek/population bias. # of LSR reports can include hail, ice, snowfall of 1"/hr or greater, storm totals. Eastward trend of TOR environment is understood. Also, having worked 1980s-90's, we just didn't have as much human kind dedication (EM's and spotter coordinators I think are now trained to do some of this for the NWS) to finding every little TOR, or time to do the job correctly. I did read NSW article. Good information.

This may be a little disconcerting to read-hear, but having worked there and other offices. LSR's are dependent in large part on population density combined with SEEKING reports and of course the reports that are received by phone, spotter reporting. The goal when I worked was to verify warnings and do a lot of post event calling, reading newspaper accounts, and in todays day, seeking reports via social media. MPing can also contribute reports. Therefore, other states are lower, in part due to processes of acquiring reports, population density and I think, priorities - available staff. This data probably should have been normalized by population. I see no other way to further normalize this data. Yes, working the I95 corridor DCA-BOS is I think a larger than normal YEAR ROUND responsibility due to population-impacts on commerce, and also the broader array of weather events that impact this region. For NJ, it can range from killer fire weather, to hurricanes, coastal flooding, severe storms, flooding, dense fog, urban heat warnings, freezing spray, ice jams, synoptic scale wind, and last but not least-heavy snow-blizzards. Not every state has this array of events (let's not forget tsunami). So the responsibility, imo, is greater here in the I95 corridor but I do think this data needed to be normalized. The data is out there now as a news story, but I do wish there would be a greater attempt at perspective, as I feel the same on all other events that we watch-warning for.

Here's some guidance to consider: available le at 530AM Sept 8. most of the rain today... NJ/NYS/PA, then tomorrow (after midnight, most of the rain LI/CT as a secondary surge is expected. Below all from 9/8/21 00z-06z modeling cycle SPC D1 outlook WPC D1 outlook WPC D1-2 qpf 06Z HRRR max 2-5KM updraft showing potential till axis of strong thunderstorms, the tmay produce svr wx, including a TOR- the latter which still looks plausible over eastern PA this eve. (also shows something up near ALB) 08Z WPC D! excessive rainfall discussion 06Z SPC SVR discussion

00z/8 HRRR and 3K NAM basically no changes through Wed night. EC is probably going to be correct about a second batch of rain Thursday, esp I95 east. HRRR and 3KNAM looking for a problem svr storm - poss tor-supercell w hail in ne PA. HRRR STP 3KNAM STP for about 00z/9. 2-5KMaxc updraft, note the large hail track identical that follows then HRRR total rain and NAM3K total rain

Am seeing dry forecasts for next Mon-Tue??? Not what the KI from the EC is saying and I'm seeing above normal PW oscillating S-N at 40 N here. Think we need to be thinking qpf on one of those days here.

A problem last Wednesday; NIGHT time... much more difficult to judge-assess, especially in near panic mode of torrential rain and some lightning. Also, I think the upgraded warnings were not NEW issuance but prior warning updates (I will stand corrected if I'm wrong but IEM COW did not show new warnings for me); TRAPPED??? EMERGENCY warnings almost too late as torrents were surcharging manhole-sewer systems and people were getting stuck, abandoning vehicles. Finally for me: how much practice do we get warning the EXTREME RECORD breaking event? Experience breeds confidence. WARNING the EXTREME in real time made me almost always pause and be more conservative because it was so seldom in my lifetime.

Moving forward... CP monthly amount should rise tomorrow between 0.2-0.8" (7.45-8.05 by 18z Thursday). This is my own goal based on multiple ensemble guidance.

Thanks Don... it is my opinion that the EC is fantastic synoptically (cool season especially), but that it lacks on convective qpf (warm season) which results in differing frontal positions and max axis of qpf. What I'm seeing in some of the guidance is dew points (strong northward moisture transport) Wednesday afternoon-night into the front with surface dews likely to exceed 70 in NYC and most of NJ. Probably briefly rises to near 73 in NYC. The TOR threat is still particularly large. Rechecked with no change. I'll update overnight and tomorrow morning by 730AM. Don't know if anyone has noticed the numerous reports in the midwest of both hail/wind including 25 reports of Large hail.