wdrag

Rainfall rate in that band in Sussex County over 1.3/hour. Here at home about .65 in the last 1.5 hours. So it is raining and I saw a CH4 news flood extraction in ne NJ earlier this morning so it is raining hard in spots.

Just saw numerous 1.5-2" amounts in a band ne NJ. Plenty of time to crank the numbers ne NJ/se NYS/w CT. Here's a sampler of 8AM reports via CoCoRaHs. Looks like plenty of rain incoming from s of NYC.

Seems hard to believe that these high res models will verify more than 4" anywhere in our area. As of 6A, seems less robust than model anticipated by this time.

19z Blend of Models...damps out the big with global lower amounts. Still has the axis pretty good.

Advance Awareness is critical as well as decision makers relying more heavily on the outlooks. My feeling is we were a little slow to get going on awareness. 3PM with less than 24 hours lead time is not enough time for the slower larger institution wheels to get going on 9/29 and 10/7 (wherever it occurs). Like winter... the earlier the better, provided we have at least 50% success. R+ summer mesoscale prediction is not excellent yet, but I do think the potency is well advertised 2-3 days in advance. We just need to believe a little more and not be afraid to be wrong (stats, peer pressure both which I think play a role in decision making). Something will go wrong tomorrow, but for now, at least the watch looks accurately portrayed. Possibly needs to be a little larger, in case the max axis shifts a little to left or right, or northward. Anyway, I'll check back tomorrow morning when action should be plentiful.

18z HRRR added

Record daily rainfall values in the POR at POU 2.51-1972 and NYC CP 4.09-1972. Add on as deemed useful Above normal small stream flows from ne NJ into extreme se NYS and w CT, plus multiple small scale modeling of 3-5" and worst case maximum 7+ prompts this topic. WPC has marginal to slight risk excessive and a watch was just issued for the primary concern area at 312PM. It's possible the small scale models have gone overboard, especially the attached FV3 HRW but the SPC MAX amount axis of over 7" and other 12z/6 max axis modeling suggests the primary area of Turn around Don't Drown concern Saturday, if any roads are inundated. Support from PW near 1.6", a 12 hour nearly stationary inflow axis Saturday morning and modeled embedded lightning. The NYC-vicinity max axis may already be forming mid afternoon Friday (monitor radar). Awareness of potential assists mitigating unexpected impacts, planning your day. Again, we'll see what the tallies are but we should not expect as an expansive area of 5+ rainfall as last Friday, though isolated amounts of 5" seem to be within reach somewhere in a 20 miles radius of NYS northward to about 30 miles either side of CT-NYS border. Axis may vary. but multi cycle modeling suggests this is one of primary areas of concern. Self explanatory 12z/6 modeling amounts by 00z/Sunday 8 Oct 2023. There we(RE NO-corrected 10/8) SPC HREF Probs of 1,2,3" in this 12z/6 cycle which suggests modeling errors. Caution but worthy of monitoring.

Also awaiting completion 12z SPC HREF and 12z RRFS. Daily records 10/7/23 CP 4.09 1972 and POU 2.51.

Starting another topic for spotty 3-6" rains tomorrow somewhere ne NJ/se NYS/w LI and w CT. some isolated FF potential, despite recovery from late last week. FV3 future GFS has spotty 8" near NYC. Looks too large and I prefer the 3-5" bands but... it's early. In a hurry now.

From what I can tell... spot 3-5" rains by Saturday 11PM, somewhere Hud Valley to just west of the Ct River. This batch of heaviest seems to be destined for just north of NYC///more likely se NYS and or w CT. 709AM/6

Excellent addition-explanation of where we may be going. Takes time. I think the SPC HREF, HRRR and RRFS should have a better idea of amounts and axis..especaily the 12z/6 versions but even the 00z/6 should be of use.

Adding on: NWS mid shift 10/5 (00z cycle) excessive guidance for Saturday was more expansive than the conservative GEFS qpf, for Saturday. See the AI left and NWS right. Click for clarity. Thanks.

This and the HRRR 48 hour were the best for the record deluge NYC last Friday. This and other models are hinting spot 3-5" NYC forum... where exactly is not confidently stated yet... but have a look at this through 22z/Saturday. Highlighted an amount near NYC...most of this Saturday. Click for clarity. 105P/5.

Yes, and a pretty good chance of above normal October rain totals. GEFS lags again (seems to in my end) through the 18th, GEPS about 2.5" and EPS 3-3.5". Obviously 00z-06z/4 ensemble projections and one of the see is large error... but the pattern evolution looks to me to be trough east this month.

Thank you for this... I guess I have to play it more conservative. Reasons: timing of the rain (nighttime is less impact on outdoor), amounts, and some folks would say you can't include Friday. Both our evals do confirm AMWX participant sentiments. Thank you again for double checking... takes time to do this. Thanks.

I take a few min to check CP ~1/2" or greater rainfall on weekend days and I've got 7/2,9,16; 8/13, 26, and 9/10,23 and the still a little wet 9/30. More or less if you use CP for cursory guidance, not the most pleasant JAS portions of weekends.

Maybe bluewave or someone else with more energy than I would like to post how often are our weekends (Sat-Sun filled with 1" or greater rain since late June? Note sure the easiest way to track it, but you all are probably more up on this than I. As you know, I've had to give up on the subtropical transition early this week as the reflux storm has tracked more se than South. However, I'm still interested in next weekend here and the following as well (7-8, 14-15). Both seem to have some sort of storminess here... whether it ends up just a 1/4-3/4" CFP, or something a little bigger with a coastal low... still tbd but I'm not done looking off the se coast for a little development later this week and northward ingest Saturday. The EPS right now lags the ever amplifying GEFS into the eastern USA next Fri-Saturday. If its flatter, then just a windy cfp. If not, then gets a little more interesting for a possible 1-3" event. Too early for me.

The wrap on 10/1: EPS prevailed in the general outlook from prior to 9/27. The mesoscale modeling, especially 12z-18z/28 HRRR and SPC HREF, and at times the RRFS and NAM nailed the potential for 5-10" amounts. NYC CP #9 wettest 24 hour day in history back to 1869 (5.48") and JFK 8.05 "wettest day in history after records began 1948. Minor coastal flooding occurred for at least one of the daily high tide cycles along the NJ coast from 9/24-10/1 with isolated moderate and certainly beach erosion of varying magnitude. We survived pretty well, partly because of prior lessons learned in NYC and partly because the primary flooding occurred during the daylight hours. Added two day event totals as a 9/30 sampling of what occurred. A little more added on Sunday after the two day totals but the essentials are here.

Near constant at least one daily high tide cycle NJ coast from Tuesday Sept 24 through today Oct 1 has had minor coastal flooding, spotty near moderate flooding, including that of today (10/1). Beach erosion had to be significant and may not know the whole story for a while.

Letting this die away quietly. Still keeping an eye off the se USA coast later this week but for now... nothing. If something got going out there, there would be a chance for something weak to sweep north toward the benchmark. For now, not modeled. Of interest, the value of differing contributing factors to big events. 9/29 NYC for example... pathetic weak surface low, but right amounts of instability, concentrated inflow lift for 18 hours and PW near 1.7". Yield-impact was pretty large there, in case you missed the news for the top 10 daily rainfall JFK, NYC CP.

Two day amount sample via reported CoCoRaHs data. Click for clarity. Highest a little over 10" NJ coast. Also added NYS Mesonet. JFK highest daily rainfall 'ever' since POR began 1948 (8.05"), and CP #9 wettest day at 5.48 with POR back to 1869. Will add a little summary to the originating section post tomorrow morning when all data in. Added 18z/28 HRRR for comparison. HRRR probably the best inside of 36 hours.

Homelife leaves me out of the loop but you're probably aware CP TOP8 or 9 DAILY rainfall ever (not just Sept). Please correct me if I'm wrong.... Thanks, Walt

And what is the pressure off the Low. Maybe 1008 MB! Doesn't take an intense low to create near record rainfall. Eye opener.

However, I continue interested in what will evolve off the se USA coast. next week. And, right now, one strong trough is forecast to evolve over the ne USA by the end of next weekend. It could easily draw at 6-18 hour swath 1.7" PW up here and depending on low pressure location provide more 1"+ rainfall. Definitely different than the whatever amounts out there (multiple 6+?). I've got to run but will be looking for CP 1 day top 10, with at least 5.7 for the calendar day as to be rerouted at 445P, and the 24 18z-18z will be at least 5.7. XMACIS says that's a top 10 daily at CP.

I went back in Pivotal wx to 12z Tue PW 1.6" which definitely sagged south and then acquired more PW east of the Carolinas and has since bulged north to LI as of 06z/29 EC op. EPS ens do not have PW on National scale. Reflux works for me but without the detail needed to confirm via soundings, trajectories. I don't want to upset anyone about this, but points well taken earlier. Looking ahead...I won't reflux what happens Oct 5-8.