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Just a model idea of how thick the smoke may be overhead tomorrow at 12z and 21z/15. Also a cross section of how it should remain at least above 5000 feet late tomorrow, tho descending closer to ground level as we go into Wednesday (modeled data not shown).

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.

Problem solved... color coding can be the confusion in high gradient pockets... it will not jump from 0.5 to 2.5" without color coded intervening ranges. It's agreed that this image is about as good as it can get. Accuracy will improve in the future years.

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.

Ap possibly incomplete preliminary wrap-up of two day totals... (MARFC radar-sensor for NJ is complete), but CoCoRaHs may update further later. Added AHPS SR two day radarCT/LI age 333PM. Have not taken the time to add up some of the wunderground two day obs for southern LI.

WU reports after midnight only are attached... (early this Friday morning). Decent leftover's near Brookhaven. Usually I don't see these appended to NWS posts, but the data is valuable=useful, if checked against surroundings and radar. Part two (all of last night) ended up less than anticipated in the page1 posts on this topic, due to the main band being south of LI instead of over LI. Still, the two day amount graphic posting late this morning will be fairly impressive in NJ/LI - well above normal for the entire week two period. I don't plan on any further topic posts for the next 5 days... awaiting the eventual tropical cyclone northward feeds. NCEP model guidance transmission appears to still have the past two days of timely delivery issues. Thank you for all of your posts-comments/impressions. Will add more around 11A. 755A/11 (818A update--just cleaned out all my attachments up through Aug 29, 2020 to make room for the future)

Have seen all model guidance shift to the southeast on heavy rainfall band. I'm reluctant to give up on it, due to instability, proximity of the front and PWAT over 2" through at least 3AM Friday BUT... I have to give up on the outside chance additional amounts for s LI that adding up to 1 ft near Copiague. I did append a MAX rainfall graphic that indicates isolated 4-5" might occur in 1 or 2 locations (this graphic begins at 8PM tonight)... if we get a nice period of training between 6PM and 3AM. If that were to occur where 4+ occurred this morning, then there would be additional overnight flood problems with a couple more reports of entire event totals over 7" on southern LI. Again, uncertainty on overlap. Elsewhere...bands developing now and so by 3A Friday... expecting a couple of 3-5" in NJ s of I80 and maybe the CT coast. That would possibly result in a couple new FFW's by midnight? Offline til 5P. Thanks for all the posts and support for this topic.

This Copiague NY data looks a touch high but has a valid zero base line. This is one of at least 8 5+ inch reports this morning s LI.

Am not quite as concerned about Sunday... not ruling it out but I think Sunday's event will be less on LI... faster flow and not quite as extensive PWAT. Potential yes, needs to be monitored. I think late today-tonight is the key for me. IF the next big band occurs s of LI...that will be the best solution. Copiague near Amitityville is our largest amount that I can find so far (7+"). By the way, there was very little or no lighting associated with the event so far on our land area, at least to my knowledge. Also have my doubts right now about the 12z NAM HRRR solutions. Need to reevaluate at 230P.

909A/10 update. Added CoCoRAHS past 24 hours and WX underground totals midnight-9A. SPCHREF MAX Rfall graphic of 7" "was" a good starting point on max rainfall. Already 4.5-7.5" parts of s LI. One foot max not impossible by 9A Friday if a number of the models are correct about training event on LI in PWAT of 2.2" tonight. The launch of this last potential prolific band seems to be centering near I78 in e PA mid afternoon and then training east this evening. HRRR and HRDPS not in agreement but prior experience from reliable sources... light north wind just north of a boundary in high PWAT can yield prolific rainfall. We shall see if that includes LI tonight... I'd prepare for flooded roads and basements there tonight, where ever 4+" occurred this morning, and methods to evacuate water should these equally big rains develop tonight. Wantage NJ-this part..0.41" now. Nothing compared to other parts of NJ and LI.

Good Thursday morning all, Radar continues to underestimate rainfall amounts. .06 here in Wantage and OKX/DIX radar did not detect any accumulation here. Added two maps of midnight-630A rainfall. one from nw NJ where you can see some of the cities. The other with a 3.06" centered on Oceanside NY (w LI).

It looks like some big numbers are coming to the I95 corridor (pockets of 3+ inches--iso 6-7"?). Digital Storm Totals from DIX and OKX are too low this Wednesday evening in s NJ. Already 1/2-1.2" amounts in parts of southern Ocean County(see attached weather underground). Look at the radar loop and you can see if that intensity comes overhead, torrential rain will occur. Long ways to go. HEAVIEST rainfall may come in two bands---one at sunrise NJ-LI, and then 3P-10P for ne NJ-CT/LI and extreme se NYS with good frontogenesis probably yielding some 1.5"+ amounts in 1 hour. 952P/9

Some of new 12z/9 guidance is in: This may be a fairly serious brief and small areas of short fuse FF for parts of NJ/NYC area, Thursday, keeping in mind previous FFG. 12z/9 SPC HREF 24 hr MAX rainfall potential. It's increased somewhat in NJ. I see 7" flagged here for 2 successive cycles in ne NJ. We'll see what happens. ICON/GGEM are pretty decent as well. 226P/9

Jut added last nights 00z/9 SPC HREF 24 hour Max rainfall graphic ending 8PM Thursday. Legend decodes the 8 member ensemble attempt at prediction.With a PWAT of 2.3"...these numbers are possible, if thunderstorms occur. Something to monitor tomorrow. Also, added the probability of 2" or more of qpf per the 00z/9 NAEFS by 8PM Monday...showing a50+% chance of 2+" on LI (back up from a few days ago). mPING may be helpful tomorrow. 931A/9

Have attached relatively high 6 hour FFG, plus the first week of Sept departure from normal rainfall, and the ~Aug 30 NAEFS 52 member D8-14 pattern that suggested near or above normal rainfall along the east coast for week two of Sept, that was posted on p2 of the Sept thread... with a cooler pattern nations midsection abutting a warmer than normal western Atlc temperature pattern. Now we're in the shorter term and modeling consensus has increased the front end of the probable two part R+ episodes -Thursday- and Sunday-Monday(13-14). 00z/9 model guidance is suggesting widespread showery conditions Thursday in the NYC forum, with some thunder. PWAT may rise to 2.3". Have seen a little ensemble guidance suggesting max rainfall of 5-7" in eastern NJ and possibly near NYC. There is enough wind that one or 2 clusters of thunderstorms might produce a wet microburst of severe weather in NJ or even LI on Thursday. My expectation is that everyone in the NYC forum receives a minimum of 1/4" and then in NJ/LI there should be several reports of 3+" with isolated 5" possible. Some of the showers may creep into the southern part of the NYC forum late this afternoon or evening but the main show is Thursday-Thursday night. There could be a couple of leftover showers leftover after daybreak Friday on LI. Normal rainfall in our area for a week period in September seems to be around 1-1.1" though our climate specialists may have other differing information. In any case, have not added Sunday-Monday to this topic... that too could be pretty heavy, though 00z/9 modeling has a slightly less extensive band of 2" PWAT over our area and a couple of models have most of the convection to our east. Would like to see the GGEM operational on board for Sunday. 726A/9

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

Pending any more data... there was 1 report of SVR in our NJ part of the forum last evening (added graphic) and added the CoCoRaHS 24 hour totals ~6A/3-6A/4