wdrag

I probably should throw in the towel on anything significant Sept 30-Oct 3; but 12z/25 GEFS still wants to separate the streams with a closed low 'trying' to form near the mid Atlantic coast, whereas the EPS has vigorous closed low up near Maine and no opportunity for significant qpf after Wednesday morning. Strange, that the EPS brings SAM closer than then the GEFS in this pattern. I guess I look at it like this: climatologically it rains every 3 days or so (trace included). I think we're pretty much assured of measurable Tuesday. After that, next measurable?? I'll check back if 12z/25 GEFS looks to be more accurate than the 12z/25 EPS, or Tuesday, whichever comes first.

For now, very little to favor widespread qpf late Sept 30-Oct3 with 00z/25 ensembles a little further se. Still think it's not impossible for a closer in low (separate from Sam). In the meantime, if we cant muster the quarter inch late Monday-Wed morning, then we will probably miss out on a 10" Sept for CP. UK is drier on this than most other modeling. Tonight: Still interesting to watch this neg tilt 500MB short wave response NYC eastward late today/tonight.

Impressions on SAM RH contributions to a substantial rainfall somewhere VA to MA Sept 30-Oct 4, offered on Saturday. Right now, it's possible but unlikely. What I do think is that this has to be monitored for a while til we're all sure it won't happen.

I see three possibilities prior to Oct1. My guess is .02 to .35 by 1AM Oct 1. Fit's Don's stats and ensembles above.

Agreed. Am looking at so called outliers starting to signal a pretty sizable event somewhere Va to Coastal New England. Not accepting any verbatim Op runs. Instead watching ens low pressure trends. My thinking this big ridge over the Great Lakes may flop east into NNE allowing closed low formation e of Cape May. That would give credence to some of the ops showing big rains near the coasts. 6 days away. This will be sensitive to Sam upper air interactions, I think. For now I think dry is too optimistic but I could be wrong.

Prelim CoCoRaHs climate obs for the past 24 hours ending about 720A. Will update this eve. Maybe a slight overperformer. Yersterdays 00z/23 HPC HREF had MAX 4-5" spot amounts but pegged more for the Catskills. Click map below to see details.

This I extracted from Don's very recent Sept post. Thought it good add here as we await further developments. Thank you for this Don!!! Central Park picked up 2.03” of rain bringing its monthly total to 9.76”. 2021 is the first year on record with 3 consecutive months of 9.50” or more rainfall. Annual rainfall in New York City has reached 51.69”. That surpassed the 51.38” that fell in 1871 to make 2021 New York City’s 34th wettest year on record.

I cannot post 24 hr CoCoRaHs #'s til late today. Those should be of interest. NYS mesonet added below as of 6A.

Unsure about EWR Sept record. Not starting SAM related thread, as yet... wait a couple of days to see if indeed there is a more direct interaction with the mid-Atlantic coast low pressure system. What I see on some 6AM weathercasts are tooo optimistically dry forecasts tomorrow and middle-end of next week for NYC-LI-NJ. I hope Bluewave and Don have some stats to share on Sept and will recheck late today.

NYC total 2.03 and 9.66 for the month as of 6A.

Correct me if this is wrong: NYC 2.03 for the storm. Monthly total 9.76. So far.

A sharp negative tilt trough out of the Great Lakes this Saturday the 24th, may place NYC on the western fringe of what could be a sizable rainfall for eastern LI, especially Montauk??? Thereafter, there are possibilities NYC will be on the northern or northwest fringe of a complex mid Atlantic coast-western Atlantic low pressure system that may yet ingest a bit of SAM RH, or at the least have it's overall Western Atlantic flow altered in such a way that LI-NYC is in the mid level deformation zone yielding qpf here of .05 to .75" next Wednesday-the 29th through Saturday October 2. Timing and northwest extent of the showery rains all uncertain but not a zero chance. Modeling of this is going may be very sensitive to overall western Atlantic response to SAM. I just don't know but worthy of monitoring. AND, as a final observation of modeling: 00z/24 guidance has virtually all members showing SAM not posing a direct threat to the northeast USA, except for 2 tor 3 members. Will monitor future modeling trends.

NYC now at 2.02" for the storm as of 510AM. Much better yield for the city than anticipated, figuring the bigger bands would miss the city. This has been a productive event.

Good Friday morning everyone, CP is closing in and within range of a first time ever 3 consecutive months of 10+". As of 510AM the storm total of 2.02" has brought the monthly total to 9.75 with a little more to go this morning before it's all over by 8 or 9A. Then we watch the sharp negative tilt trough out of the Great Lakes this Saturday the 24th, to see if NYC is on the western fringe of what could be a sizable rainfall for eastern LI, especially Montauk. Thereafter, there are possibilities NYC will be on the northern or northwest fringe of a complex mid Atlantic coast-western Atlantic low pressure system that may yet ingest a bit of SAM RH, or at the least have it's overall Western Atlantic flow altered in such a way that LI-NYC is in the mid level deformation zone yielding qpf here of .05 to .75" next Wednesday-the 29th through Saturday October 2. Timing and northwest extent of the showery rains all uncertain but not a zero chance. Modeling of this is going may be very sensitive to overall western Atlantic response to SAM. I just don't know but worthy of monitoring. AND, as a final observation of modeling: 00z/24 guidance has virtually all members showing SAM not posing a direct threat to the northeast USA, except for 2 tor 3 members. Will monitor future modeling trends.

By my count as of 430A: NYC CP at 9.46" for the month, still counting. storm total 1.73 and still rising. Need to reverify at 5A.

Wantage NJ (this part). Final 2.24". Updating NYC mo total thread shortly as they near 9.5".

Some rainfall today as of 8P.

1.57 so far today in this part of Wantage NJ. higher amounts juste w of Wantage in Sussex County NJ.

0.94 6P-8P including 0.86 in 1 hr ending 750P. Mo total 8.67 as of 8P/23. Depends on what occurs overnight but prob less than 1". Then depends on whether we get a coastal 29th-30th. Long shot all.

Rainfall so far today in NJ/NYS per climate mesonet sites.

Wantage NJ 8 s High Point: 1.42 so far.

Been lots of thunder up here in Sussex County NJ since 130P. Wantage NJ storm total now 1.24"

Wantage NJ 4sw just had a 2.8"/hr rfall RATE. for there day 1.19, most of that since 339P.

After whatever happens by 8AM Friday the 24th, there will be one or two more opportunities for rain before the end of the month. Whether CP makes 10"will be largely dependent on what happens tonight. Presuming it's under 1.7", then reaching 10 this month is very unlikely. Thread for tonight has been started.

While most of the NYC subforum will have a routine moderate or heavy rainfall, there could be narrow corridors of excessive rain. Some of the guidance shows max possible rainfall in our area of ~4" but most of it is in the range from near 1/4" e LI to between 1/2 and 2" elsewhere. The primary time for heaviest weather is 6P-4A tonight. Please monitor NWS watches/warnings/statements on FF/SVR.