wdrag

Wed-Thu ould produce anywhere from .05 to 1" NYC-CP. It's add on, whatever it is.

Raining out here in Wantage NJ without any radar echo our way. .04 for the day. everything wet. Also, am seeing steady rains entering s NJ from s PA. to me, looks like going to be widespread 0.1-0.7" amounts southern LI down to near I78 between now and 10AM Monday.

I see CP has added .01 today to far.

Am not sure what will change the pattern? MJO i suppose or some huge tropical exchange with the polar region. All i see is another year of warmer than normal as represented by sea breeze summer cooler NYC data...7 of the first 8 months of 2021. I aw the 00z/5 MEX MOS guidance for NYC this morning and it starts at or above normal for many days... beginning the 6th. I'm not sure about Wed-The but warmth is apparently coming. Later, Walt

So even though amounts are miniscule, it is wet and not too sunny. 0.02 here in Wantage NJ at 1121AM. Two things about this minor (so far) event, it's trackable and I sort of wish those that are showing 10 day forecasts, would look at PWAT changes and ensembles to minimize these optimistic longer range outlooks. Basically it rains a bit, every 3 days. Therefore if its not, we need to be sure about ridging and no instability -moisture encroachment. For now much of nw NJ, nePA and distant interior se NYS have measured .01-.05 a bit more along the northern fringe of the NYC subforum. This day is far from over, and modeling continues to spew a narrow 1/2+ stripe somewhere in our NYC subforum by tomorrow morning. PWAT axis looks a little larger to the south of I80 so I suppose it can miss the region north of us, but there is likely to be a little bit of convection rolling across parts of I84 tonight.

Yes, you're probably going to be right... that would fit the opportunity for our NYC attempt at 10+.

So we dawn this Sunday with leftover Nora's showery moisture approaching from the west giving sprinkles in some areas by daybreak Monday, while others have 0.1 to possibly isolated 1". See WPC qpf for the general coverage today-tonight in 2 or three bands of 1/2-3 hours duration. It is what has been trackable for many-many days, obviously far removed from its Baha source region, having been clipped a bit by the Rockies, but will affect haying-corn retrievals here in nw NJ the next 24 hours.

Looks like warming w respect to normal begins to normal... whether its continuous or interrupted by the next trough midweek, unknown but overall September looks to be heading to the warmer than normal side of the ledger by mid month. Continue to look to the period after the 17th for opportunity for possibly more significant TC moisture. For now, am seeing the midweek tropical moisture in the se USA just passing se of us. So Larry's swells-rip current impact is the apparent biggest TC related action this week for our asubforum, with Nora's moisture contribution noticeable today-tonight but small.

Processes will be improved including modeling a 2 hour window of potentially overwhelming-excessive rainfall and then it's up to us to get the message out out 2 hours in advance, not within it's occurrence for which i'm afraid entrapment was occurring on roads near creeks and near overwhelmed drainage basins. Scary in that situation, and what to do becomes a problem.

Yes... looks a little drier than normal through the 17th, after, all bets off... So anything we get this week in CP adds to the 7.23" so far. GEFS starting to show more and more TC options. The one in GMEX-HAT around the 8th-9th is not for us, I dont think, unless abrupt upper level changes develop with the approaching Great Lakes trough middle of next week. So not counting on that but monitoring. After the 17th might be something that allows trop PW this far north, but it seems it will have to come from GMEX. Added CPC week 3-4, issued once weekly on Fridays.

There should be showers or sprinkles Sunday morning and then if the 06z/4 HRRR is to be believed late day I95 east, and then possibly later Sunday night whatever survives with the frontal passage from the west. I dint have much to add this morning...models differ. Nora contribution impact this morning from CO to MO, attached. Use the legend for a little more assistance.

So when the topic started, anticipated a rather warm first week of Sept - overall it will not be. TC moistures were anticipated and both are going to occur, however in a huge reverse order with IDA almost 5 days sooner than originally expected and Noras leftover PW about 4-5 days later than expected. Worthy I think to pay attention to developments after the 17th in the western Atlantic to Gulf Coast. Maybe this is premature so I'll follow with probably no GMEX TC related thread post for at least a week. Finally, at the behest of WPC-NWS, they prefer all of us on the same page and not naming these TC's up here as remnant (despite IDA being half to 65% of what it was striking Louisiana). Any future TC posts from myself will somehow migrate over to Post TC or TD. That will take that issue off the table as a hindrance to messaging, if indeed it was significant.

Well, I don't know yet what to believe, but the potential exists for anywhere from a trace to isolated 1" rains Sunday early Monday. Minor in comparison to IDA impact here. In my mind Nora's PW has influenced the weather in in the central Rockies-into central Plains and we'll see a piece of it by Labor Day. I think it's worth tracking tropical PWATS as we do Atmospheric Rivers across the Pacific for the western USA in winter. We'll see what happens. It obviously is not major but it to me appears to be coming with 850 MB wind core and an increasingly favorable 500MB jet core diving down to 40N to sweep the PWAT east toward Delmarva/NJ/LI.

While this remnant TC moisture plume is probably hard to discern and am sure most if not all are reluctant to ascribe the coming Sunday-early Monday shower event to Nora's RH, I will. The initial burst is Sunday morning and how much elevated convection remains as it crosses the area is debatable but have to think there will be some showers in the associated instability burst (850 MB sw speed max crossing PA-NYS). 500 MB winds are not favorable for a large event here. There could be another burst of showers in the leftover moisture late Sunday or Monday morning. All totaled, as per WPC, probably less than 1/4". Should be a non player in leftover receding waters of Post Trop IDA.

We'll need some sort of organized program. Either that or we can conference 2 -4 folks somehow. Am not a super specialist on technical but can get it done. Not til after 3P.

Have placed my final review in the original IDA thread and answered a question on how to access some pretty good predictive data that I think WPC relies upon, maybe more so than specific ensembles for the first 48 hours.

Check this out from the 12z cycle yesterday, available by 1530z when less than 0.10" had occurred NYC while I was near 0.9" in extreme nw NJ. https://www.spc.noaa.gov/exper/href/?model=href&product=snowfall_024h_mean&sector=conus Change the date and cycle. Change the area of interest down from CONUS to NORTHEAST. Then go to precip and review 24 hour MEAN at the three 24 hour intervals provided. Then click MAX and check for the same time. I do the same for snow. Also, can look at hourly mean ptype/amount, ditto wind (found under FIRE). It's a tool...imperfect but I and believe WPC think it's the best available, for now. EC has a lot of fans but is inadequate when it comes to convective release (secondary imo to the NCEP GFS). ANY questions: write me. I could conduct a ZOOM on how to use all these tools in predictive sense, but all who participate must have pretty good internet.

CoCoRaHS data as of 9A, and some reports possibly delayed where no power. The red is the max wsw-ene axis near I95 which favors SPC HREF and GFS modeled axis as best forecast, along with EPS GEFS swath primary 2+ rainfall. The 10"s were possible. Added Radar-sensor combined. Appears to be 1/2-1" too low for yesterday. Also added yesterdays 12z/1 SPC HREF showing general 5" swath just nw of NYC but also look at the max for same time period showing the spotting of 10-15" across NNJ to s CT. CLICK MAPS for greater clarity of each. Finally some perspective: These amounts have occurred in the recent decade and will again, but over the identical areas as yesterday--- possibly not, but close. We can go back to the historic tropical data base into the mid 1950s when I was a kid floating toy boats down the rain swollen streets in Newton NJ in 1955 (Connie-Diane in an 8 day period of early August). Yesterdays problem was in part antecedent conditions but I think mostly, that 80% of the rain fell in less than 3 hours. NO URBAN SYSTEM can handle that unless budget allocations change and there is too much else to care for. Finally: misuse of data is too much drama. For instance: Unprecedented use of the term Flood EMERGENCY. NWS implemented that I think it was 2017-18. Not a very long period of record. I also think the same on recurrence interval. We simply don't have reliable data. Tentatively: I will log this as a moderate event on the edges BUT major where 8"+ and deaths which is near and just north of I95 corridor. The MAJOR 8+ was much more extensive than I had capability of confidently predicting including over NYC. (Not much flooding here in Wantage Sussex County NJ despite 4+". Have a few road closure due to wind related downed branches) The TOR added spice but this was mainly a heavy rain event with gusty winds 40-60 MPH causing the uproots, branch breakage-power outages.

Hope folks are checking the SPC HREF, which WPC follows closely for its D1-2. VERY VERY good.

Will update this wrap-up post around 10A with more data. Prelim: CoCoRaHS data as of 720A, and reports possibly delayed where no power. The red is the max wsw-ene axis near I95 which favors SPC HREF and GFS modeled axis as best forecast, along with ENS. The 10"s were possible. Will detail the data when i can later on today, by which time you'll have many NWS lists. Added Radar-sensor combined. Appears to be 1/2-1" too low for yesterday. Also added yesterdays 12z/1 SPC HREF showing general 5" swath just nw of NYC but also look at the max for same time period showing the spotting of 10-15" across NNJ to s CT. Finally some perspective: These amounts have occurred in the recent decade and will again, but over the identical areas as yesterday--- possibly not, but close. We can go back to the historic tropical data base into the mid 1950s when I was a kid floating paper boats down the rain swollen streets in Newton NJ in 1955 (Connie-Diane in an 8 day period of early August). Yesterdays problem was in part antecedent conditions but I think mostly that 80% of the rain fell in less than 3 hours. NO URBAN SYSTEM can handle that unless budget allocations change and there is too much else to care for. Finally: misuse of data is too much drama. For instance: Unprecedented use of the term Flood EMERGENCY. NWS implemented that I think it was 2017-18. Not a very long period of record. Tentatively: I'll review further but I will log this as a moderate event except major where 8"+ and deaths. The MAJOR 8+ was much more extensive than I had capability of confidently predicting as well as over NYC. (Not much flooding here in Wantage despite 4+".) The TOR added spice but this was mainly a heavy rain event with gusty winds 40-60 MPH causing the uproots, branch breakage-power outages. Added NYS Mesonet just after initial post.

Prelim: CoCoRaHS data as of 720A, and reports possibly delayed where no power. The red is the max wsw-ene axis near I95 which favors SPC HREF and GFS modeled axis as best forecast, along with ENS. The 10"s were possible. Will detail the data when i can later on today, by which time you'll have many NWS lists. Added Radar-sensor combined. Appears to be 1/2-1" too low for yesterday. Also added yesterdays 12z/1 SPC HREF showing general 5" swath just nw of NYC but also look at the max for same time period showing the spotting of 10-15" across NNJ to s CT. Finally some perspective: These amounts have occurred in the recent decade and will again, but over the identical areas as yesterday--- possibly not, but close. We can go back to the historic tropical data base into the mid 1950s when I was a kid floating paper boats down the rain swollen streets in Newton NJ in 1955 (Connie-Diane in an 8 day period of early August). Yesterdays problem was in part antecedent conditions but I think mostly that 80% of the rain fell in less than 3 hours. NO URBAN SYSTEM can handle that unless budget allocations change and there is too much else to care for. Finally: misuse of data is too much drama. For instance: Unprecedented use of the term Flood EMERGENCY. NWS implemented that I think it was 2017-18. Not a very long period of record. Tentatively: I'll review further but I will log this as a moderate event except major where 8"+ and deaths. The MAJOR 8+ was much more extensive than I had capability of confidently predicting as well as over NYC. (Not much flooding here in Wantage despite 4+".) The TOR added spice but this was mainly a heavy rain event with gusty winds 40-60 MPH causing the uproots, branch breakage-power outages. Added NYS Mesonet just after initial post.

September second dawns with NYC having been doused with ~7.2" of rain from the remnants of IDA, resulting in death and major flooding in the NYC metro area. September normal rainfall is about 4.31". The target is 10" for September, which is possible and would be a first time in the 150+ year history (POR back to 1869) of CP record keeping. AND, iffff we get to 10", can the 3 month total in 2021, exceed the 3 month ASO 2011 total of 34.43"? There may be opportunity, dependent on the latter half of December steering flow. Have not checked other 3 consecutive month totals for CP in the database, so there may be an even larger value somewhere in there.

No comment: Please see NWS issuances on those stage details. I'm just going back as I can to find the IRENE-LEE storm totals for now.

Nora remnants - minor but coming. Added PW axis seen in Rockies aligning east and shooting to the mid Atlantic States by Sunday. Amounts small and may only be scattered but showers are coming Sunday the 5th. If the timing delayed from Sunday morning to Sunday afternoon and the modeled CAPE increased, we'd be looking at a pretty decent band of convection but for now, ensembles are under 0.2 inches.