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Again, for those that are interested. Nothing circular in that radar presentation... this is classic AP. A loop of the radar would show a migration if any ... very highly doubt birds. Instead insects, moisture discontinuities with inversions developing and hills intercepted. I did check with a retired NWS specialist.

Difficult for me to easily explain in lay persons language. Temp/dew of 35/32 should yield a wet bulb of about 33, cold enough to snow. Need that wet bulb at or below about 33.5F to have a chance of snow in a non convective situation. Dewpoint is the commonly referred indicator of discomfort (or lack of) in warm season. Wet Bulb Temperature - Twb The Wet Bulb temperature is the temperature of adiabatic saturation. This is the temperature indicated by a moistened thermometer bulb exposed to the air flow. Wet Bulb temperature can be measured by using a thermometer with the bulb wrapped in wet muslin. The adiabatic evaporation of water from the thermometer and the cooling effect is indicated by a "wet bulb temperature" lower than the "dry bulb temperature" in the air. The rate of evaporation from the wet bandage on the bulb, and the temperature difference between the dry bulb and wet bulb, depends on the humidity of the air. The evaporation is reduced when the air contains more water vapor. The wet bulb temperature is always lower than the dry bulb temperature but will be identical with 100% relative humidity (the air is at the saturation line). Combining the dry bulb and wet bulb temperature in a psychrometric diagram or Mollier chart, gives the state of the humid air. Lines of constant wet bulb temperatures run diagonally from the upper left to the lower right in the Psychrometric Chart. Dew Point Temperature - Tdp The Dew Point is the temperature at which water vapor starts to condense out of the air, the temperature at which air becomes completely saturated. Above this temperature the moisture will stay in the air. If the dew-point temperature is close to the air temperature, the relative humidity is high, and if the dew point is well below the air temperature, the relative humidity is low. If moisture condensates on a cold bottle from the refrigerator, the dew-point temperature of the air is above the temperature in the refrigerator. The Dew Point temperature can be measured by filling a metal can with water and ice cubes. Stir by a thermometer and watch the outside of the can. When the vapor in the air starts to condensate on the outside of the can, the temperature on the thermometer is pretty close to the dew point of the actual air. The Dew Point is given by the saturation line in the psychrometric chart.

Adding on to the coming cooler trend expressed above in Bluewave post...NAEFS D8-14 (Sept 22-29)attached pretty much is cooling us a little a closer to the monthly normal from the above normal first two weeks of Sept.

Good Monday morning everyone, Sally should pass out to sea well south of our area, per NWS guidance as added below. The only major model uncertainty is the CMC ensemble which biases the NAEFS rather wet up here with southerly flow 850MB moisture contribution and potential mid-level FGEN. Ensemble guidance of 00z/14 EPS/GEFS is also wetter than the 00z/14 operational cycle and seems to have trended slightly north from yesterdays post of 00z/13. The NAEFS prob for 2" axis is directed into the northeast USA for Thu night-Friday. So, this is posted not to say Sally will impact our area with moisture contribution but forecaster's considerations that may need blending higher? QPF is yes/no. In this case, operational modeling says much more strongly NO, but ensembles suggest another look see is required. Monitor the future trends to see if a somewhat wetter scenario will develop for the I95 corridor of the NYC forum late this workweek. It's basically our only hope for substantive qpf between the event of this past Wed night-friday morning (9th-11th) and Tuesday Sept 22nd. 648A/14

On Sally: not starting a topic until I see a decent chance of 2+" of rain in our forum(would have to be southeast edge) or resultant pressure gradient creating gale-tropical northeast wind gusts. Right now the NAEFS prob for 2" is less than 20%. Most of the guidance is a potential grazer contributing impact for the southern edge of our NYC forum. So yes, Sally might contribute-enhance potential for a brief nor'easter?? but I don't think it's worth a topic at this point due to likelihood of main hazard risk being only for marine (gale gusts s&e of LI?). You're welcome to start a topic-just doesn't look abnormal to me (at least for rain, and should not be much, if any, player in se NYS which missed a lot of this past Thursday's rain). Graphics: Added 00z/13 EPS, 06z GEFS 24 hr rainfall ending 00z/Sat, and 00z EPS Sally tracks, plus 24 hr NAEFS rainfall for Wed, Thu, Fri-just check the legends. Isohyets In MM, so 10 MM, is about 4 tenths of an inch. Variability of ensemble rainfall is color coded in the legends. Basically this post is in agreement with WPC D1-7 QPF from earlier this morning. 753A/13

I don 't think so. Not likely after sundown... and the best way to see is a loop where you can see them moving, best time tends to be near sunrise.

So it's trending closer for late Thursday or Friday. Added 12z GEFS/EPS tracks which are decidedly closer than the 820AM post. Also NAEFS 52 member mean which offers us on the northern fringe of near 1/2" (10MM). NAEFS probs for 2" are not in yet. Fast moving but a possibility of rainfall enhancement Friday, if it doesn't pass too far south. For now, the trends in the past 12 hours are slightly more favorable.

Regarding the probable development of (TD19 as of 12z/12) Sally in GOMEX. Has a currently UNLIKELY but small chance of contributing moisture ahead of an approaching cold front moving into our area late this coming week (Thu-Fri 17th-18th?) Here's the 00z/12 EPS... 00z/12 GEFS does not have it for us (furthest north is dark brown track), but a few from the EC ensemble attempt a newd drift toward PA. No topic planned for this for at least another day or two, to monitor overall 500MB pattern. 821A/12

Forgot to add the radar appearance quote from mweisenfeld. Not Birds: AP with temperature inversion developing near or after sunset. Shows some nearby non-moving targets near radar and not too distant hills. Here is more information below. Extracted from sensAgent.com The position of the radar echoes depend heavily on the standard decrease of temperature hypothesis. However, the real atmosphere can vary greatly from the norm. Anomalous Propagation (AP) refers to false radar echoes usually observed when calm, stable atmospheric conditions, often associated with super refraction in a temperature inversion, direct the radar beam toward the ground. The processing program will then wrongly place the return echoes at the height and distance it would have been in normal conditions.[2] This type of false return is relatively easy to spot on a time loop if it is due to night cooling or marine inversion as one sees very strong echoes developing over an area, spreading in size laterally, not moving but varying greatly in intensity with time. After sunrise, the inversion disappears gradually and the area diminishes correspondingly. Inversion of temperature exists too ahead of warm fronts, and around thunderstorms' cold pool. Since precipitation exists in those circumstances, the abnormal propagation echoes are then mixed with real rain and/or targets of interest, which make them more difficult to separate. Anomalous Propagation is different from ground clutter, ocean reflections (sea clutter), biological returns from birds and insects, debris, chaff, sand storms, volcanic eruption plumes, and other non-precipitation meteorological phenomena. Ground and sea clutters are permanent reflection from fixed areas on the surface with stable reflective characteristics. Biological scatterer gives weak echoes over a large surface. These can vary in size with time but not much in intensity. Debris and chaff are transient and move in height with time. They are all indicating something actually there and either relevant to the radar operator and/or readily explicable and theoretically able to be reproduced. AP in the sense of radar is colloquially known as "garbish" and ground clutter as "rubbage". Doppler radars and Pulse-Doppler radars are extracting the velocities of the targets. Since AP comes from stables targets, it is possible to subtract the reflectivity data having a null speed and clean the radar images. Ground, sea clutter and the energy spike from the sun setting can be distinguished the same way but not other artifacts.[2][3] This method is used in most modern radars, including air traffic control and weather radars.

Good morning this Labor Day 2020, Yesterday: no showers late afternoon evening s of I84... a few just n of I84 in se NYS and sw CT. No thunder per lighting archive. The week from Tuesday through Monday the 14th. Less chance for 2+" rains (near out above normal qpf), per the Rockies cutoff slowing and opening up late, but not yet a done deal for less. This coming Wed-Thu, and Sunday and Monday still may see significant qpf production around here. We seem to be more on the northern edge of decent qpf but some room for modeling error exists. PW rises to near 2" with pairs of days. Any showers outside those 4 days would appear to be an unexpected bonus. 634A/7

For next week: No change in overall modeling posted from the NAEFS since Sunday the 30th, supported by other forum participants looking at varying guidance. It's looking like normal or above normal QPF for much our our area between Tue and next Monday the 14th. With PWAT near 2" late Tue through next weekend... some places will have 2+" inch totals... conceivably much heavier, but, overlapping daily or every other day rains are not guaranteed and so no numbers offered above 2" at this time. Sunday (tomorrow) not only has a decent shower threat along and north of I80 in the afternoon, there could be low top isolated thunder. 3P/5

Next week continues of interest, as it appears the ensembles are slowing the central USA trough and building a strong ridge along the e coast...with lots of southerly component. 00z/4 NAEFS reflects... showers develop Monday night or Tuesday (inverted trough early-mid week) and continue intermittently through Monday the 14th. Presuming some days will be rain free... Haver added a week long graphic that now has an ensemble 40-50% probability of 2" Long Island. It's also becoming a little clearer, that one axis of heavy precip will be west of the Apps, and another along the USA east coast with a relatively low qpf expectation between. Finally-Sunday the 6th...still to me looks like isolated or sct showers about the NYC forum area per KI pooling in weak WAA? 1023A/4

Poured here in Wantage between 11P-2A but wifi power interruption prevents accurate accounting. At least 1.1" at that time and Digital Storm Total shows some nr 2" amounts around here in nw NJ. No topic on SVR today, at least not yet. Most of the activity in our forum should be 6P-midnight with the bulk of svr just s of of our forum. If any SVR, think it's mainly Ocean County. Not enough CAPE imo. Will rereview early this afternoon. As an aside, many talking about rain free weekend...not so sure about Sunday. Seems like more clouds and a pooling of KI across our area. My guess there will be a couple of showers around in the afternoon. Monday is the warmer beach weather day (safely distanced). Trough evolution central USA next week seems more positively tilted but Wed--Fri, should rain decently in parts of our area with potential for 2" totals somewhere. 652A/3

So, I'm aware of the watch just to our sw. I expect a combo of the HRRR and HRDPS to handle timing-coverage. RE: SVR? I doubt in our area but cant rule it out. My guess is a broken line of showers with embedded thunderstorms... a few of which will produce .25 to 1" of rain in 1 hour and maybe a G40-45 MPH. These storms should be decaying as they enter NYC 1A-3A Thursday. Will reevaluate Thursday evening, around 645A Thursday. May post again, if its surprisingly big here in Sussex County toward 11P-mid tonight. Otherwise... this is my last post of today.

Is it true... mPing has returned? I think it has... here is a twitter report. NOAA NSSL @NOAANSSL · 1h Get your phone ready - mPING is back! Download the updated app to report the #wx near you! Already have the app? Redownload the app for the latest updates. https://mping.nssl.noaa.gov

1.00" in Wantage NJ so far, since 5AM. No SVR topic planned, so far. SPC D2 afternoon update said this about it's Marginal for our area. ...Hudson Valley into Southern New England... There may be some potential for strong/gusty winds to occur north of the more robust convection across the Mid-Atlantic Thursday evening/night. Low-level warm advection would be the main forcing mechanism. However, most 12Z guidance does not suggest strong storm development across the Hudson Valley into southern New England late in the period. Have therefore trended the Marginal Risk southward a bit, but still including the NYC metro and far southern New England in case convection develops a little farther north than currently forecast.

0.97 so far... since 5A. Not well modeled. Surprised HRDPS missed this on its very short term forecast.

Wantage NJ... 0.69" so far since 5A.. beneficial!

Wantage NJ 0.54" so far 5A-8A. Definitely valuable rainfall.

Good Wednesday morning all: welcomed rains here in far nw NJ since 5A..so far 0.37". No topic on the SPC D1-2 marginal risks parts of our area next two days: You're welcome to add this as a topic. Aside from a wet Wednesday morning in far nw NJ/se NYS /CT, I see a band or two of heavy showers/tstms sometime after dark both this evening and Thu evening, but EC modeled CAPE continues meager in our area; so if SVR makes it into our forum area, my expectation is only a couple of reports, mainly western/central NJ. Still time to add asa topic if model favorability improves. On next week: I added a 00z/2 NAEFS prob of 2" or more of the entire period. This is a decent ~30% chance, a week in advance. EPS only has near normal anomaly next week while the GEFS is definitely wetter than normal. This far in advance, at least our trough-ridge position is favorable for qpf... but the targeted, repeat episodes is uncertain and should be focused along the quasi-stationary boundary, and upslope regions- which could be a little to our west? 720A/2

Modeling via the ensembles continues to suggest next week (7-14), will provide us near normal qpf, maybe above normal interior a below eastern LI? Several events and somewhat depends on position of a possible quasi-stationary front the eastern seaboard. This as per several graphics posted from various members the past two days. One thing that from my perspective will be less evident than in summer... heavy convection, due to shorter-cooler days. So, I think we're going to need a boundary to help us out, aside from the upslope interior mountain ridges. If it ends up the flow is southerly, rather than southeasterly, then we have more opportunity for LI/CT to see some decent showers from the lift of the southerly flow over the landmass. Lots of unknowns. Regarding the SPC depicted D3 marginal severe for our area this Thursday... holding off as a topic at this time. It is late in the season, and the EC does not have enough CAPE-KI, in my opinion, til evening. The winds aloft - modeled and discussed by SPC will be in place, but the CAPE-KI are slower to arrive in our forum than the 06z/1 GFS models. Otherwise...seems like periods of showers-drizzle the next two days (today-Wednesday). 657A/1

Saw the several posts today on the longer range: I agree... looks interesting. Adding the NAEFS D8-14... thats' been consistent for a couple of days now... how it evolves is unknown (pieces for northern stream, or maybe cutoff something down in TN?) What this flags for me is a southerly component and potential for increased rainfall. Maybe most of it will be Apps west? I'll guess maybe a little closer to normal for most of our area, than what we've experienced since Isaias. This outlook would be for September - week two.

Did anyone notice a very recent tweet from Eric Blake? I can't access this on trop tidbits, but credit goes to Eric Blake, also apparently just promoted to Senior Hurricane Forecaster there. After August 20 a big change in shear across the Atlantic Basin. It's an excellent hint at changes to come around the normal time of basin increase. I can delete this post if you wish. Just caught my attention on trop tidbits. I can't move the loop over to this forum but credit Trop Tidbits-Levi and Eric Blake. Really nice illustration of before and after the Madden-Julian Oscillation passage in the Atlantic from the GEFS-parallel. Note the initial high shear (red) in the deep tropics, then the late Aug transition to lower shear (blue) through the first part of Sep @TropicalTidbits @EricBlake12 · 40m Really nice illustration of before and after the Madden-Julian Oscillation passage in the Atlantic from the GEFS-parallel. Note the initial GIF

Agreed... though one positive for the early Euro on Isaias... it sensed a struggle from start up to ~FL...in other words it was so weak it kind of knew conditions were not very good. That's my take away when models disagree, especially longer range=caution. That's one reason was very broad in the NYC forum topic starter outlook. Didn't want to overplay the hand.

I'd heard of that near LA and absolutely-common sense! Have no idea of NWS plans. I think the military has been using WBGT as their guide for 50+ years. Posted this article because of the Law relating to HI litigation. This may accelerate research-and any subsequent change and comments. I've drifted away from descriptive adjectives spicing up the weather and just letting the numbers dictate local action.