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Less ominous than late last week, but a narrow stripe of 3-5" rainfall by 3PM Saturday seems destined from near NYC metro north into se NYS and w CT...with most of potentially excessive rain midnight-Noon Saturday 10/7


wdrag
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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. 

Screen Shot 2023-10-06 at 2.51.41 PM.png

Screen Shot 2023-10-06 at 2.57.33 PM.png

Screen Shot 2023-10-06 at 2.58.36 PM.png

 

Screen Shot 2023-10-06 at 3.02.58 PM.png

Screen Shot 2023-10-06 at 3.05.46 PM.png

Screen Shot 2023-10-06 at 3.00.45 PM.png

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15 minutes ago, wdrag said:

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 SPC HREF Probs of 1,2,3" in this 12z/6 cycle which suggests modeling errors. Caution but worthy of monitoring. 

Screen Shot 2023-10-06 at 2.51.41 PM.png

Screen Shot 2023-10-06 at 2.57.33 PM.png

Screen Shot 2023-10-06 at 2.58.36 PM.png

 

Screen Shot 2023-10-06 at 3.02.58 PM.png

Screen Shot 2023-10-06 at 3.05.46 PM.png

Screen Shot 2023-10-06 at 3.00.45 PM.png

18z HRRR added

Screen Shot 2023-10-06 at 3.55.05 PM.png

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  • Rjay pinned this topic

It's certainly going to be interesting to see how this plays out overnight and thru tomorrow afternoon. Definiately a nowcasting event for sure. Flood Watches issued just to my north and east in Union County/Staten Island but as per some of the modeling I can see portions of Middlesex, Somerset and Monmouth Counties NJ also getting in on some of the heavy possibly exsessive rainfall. We'll see.

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1 hour ago, Rtd208 said:

It's certainly going to be interesting to see how this plays out overnight and thru tomorrow afternoon. Definiately a nowcasting event for sure. Flood Watches issued just to my north and east in Union County/Staten Island but as per some of the modeling I can see portions of Middlesex, Somerset and Monmouth Counties NJ also getting in on some of the heavy possibly exsessive rainfall. We'll see.

Seems every event lately is a now casting event?  I no longer have the skill or courage to make an educated guess, but I'm sure others out there (including our forum) which can make a rational call.  In my day, we had very little tools; LFM, Baroclinic, MOS outputs.  However, I agree with this event that the max hot spots will be next to impossible to pinpoint.

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10 minutes ago, Dark Star said:

Seems every event lately is a now casting event?  I no longer have the skill or courage to make an educated guess, but I'm sure others out there (including our forum) which can make a rational call.  In my day, we had very little tools; LFM, Baroclinic, MOS outputs.  However, I agree with this event that the max hot spots will be next to impossible to pinpoint.

I can only imagine what the news headlines will be for areas that experience the heaviest rain/flooding. The public and some news media will be pointing fingers once again like last weekend.

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1 hour ago, Rtd208 said:

I can only imagine what the news headlines will be for areas that experience the heaviest rain/flooding. The public and some news media will be pointing fingers once again like last weekend.

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. 

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1 hour ago, Brian5671 said:

HRRR is starting to show very little east of the Hudson through noon

This is looking like the type of event in which there will be a band of very heavy rain (2 to 5 inches), but mostly light amounts outside of that band. 0z HRRR is showing very heavy amounts for the Jersey shore up through NE New Jersey, but light amounts for most areas west of there. I am right near the edge. Don't know if I'm gonna get a quarter inch or a few inches. Very tough to predict. 

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10 minutes ago, winterwx21 said:

This is looking like the type of event in which there will be a band of very heavy rain (2 to 5 inches), but mostly light amounts outside of that band. 0z HRRR is showing very heavy amounts for the Jersey shore up through NE New Jersey, but light amounts for most areas west of there. I am right near the edge. Don't know if I'm gonna get a quarter inch or a few inches. Very tough to predict. 

Just through 12z. It's like all or nothing

qpf_acc-imp.us_ne (31).png

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12 minutes ago, Stormlover74 said:

3knam has a nice line

ref1km_ptype.us_ne (8).png

And it gets heavy amounts much further to the west than HRRR. HRRR performed very well for the last event while 3km NAM did not. HRRR was spot on with the sharp cutoff near our area. I would lean towards the HRRR for this event (sharp cutoff near our area again), but of course you never know. 

Meanwhile the regular NAM isn't impressed with tomorrow at all, but of course that's a horrible model that shouldn't be given much weight. 

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7 minutes ago, winterwx21 said:

And it gets heavy amounts much further to the west than HRRR. HRRR performed very well for the last event while 3km NAM did not. HRRR was spot on with the sharp cutoff near our area. I would lean towards the HRRR for this event (sharp cutoff near our area again), but of course you never know. 

Meanwhile the regular NAM isn't impressed with tomorrow at all, but of course that's a horrible model that shouldn't be given much weight. 

Yep will have to just watch the radar

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6 minutes ago, wdrag said:

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. 

Heavy rainfall delayed but not denied? It looks like the radar is starting to fill in a bit. We'll see.

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