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September 2020 wx discussion

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2 hours ago, JoshSnow said:

The sun will be turned to darkness and the moon to blood before the coming of the great and glorious day of the Lord.

tell the lord to put out the f'n fires already

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The next 8 days are averaging 65degs.      Make it 60degs., or -8.

59*(73%RH) here at 6am, m. clear.          71* by 4pm.

The Tropics:   30.2N  87.7W( I have arrived), 42N 49W,    16N 49W,    22N, 34W,  and New at 9N 23W.

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52/50 off a low of 44.  Warmer the next 48 hours 70s today and perhaps 80s tomorrow with enough sun before the big / longer cool down arrives Fri night.  Sat (9/19) - Tue (9/22).  Another brief warmup looks likely by Wed (9/23) ahead of a back and forth cooler by Fri (9/25).  The month looks to end on a warmer side as ridging pushes into the east.  Overall the next week looks  dry and extending beyond.  Teddy near Halfax or New England?

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40s this morning, probably the coolest weather since May or about 4 months. 

Looks really cool this weekend and I wouldn't be surprised to see lows undercutting guidance by several degrees so upper 30s maybe? 

Interesting that forecast discussion points out smoke will keep temps down several degrees today. Likely had an impact yesterday as well. 

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14 hours ago, ny10019 said:

anyone else sneezing/coughing/sore-ish throat today? I'm not sure if the wildfire smoke is irritating me or just regular allergies 

Air quality is still considered good. The smoke is too high to affect air quality at the surface. At least that is the offical forecast. For me the cooler, and espically drier air recently is an asthma trigger. 

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Morning thoughts...

Today will be sunny and somewhat milder. Temperatures will likely reach the lower 70s across the region. Likely high temperatures around the region include:

New York City (Central Park): 71°
Newark: 73°
Philadelphia: 73°

Tomorrow will be milder, but an even colder air mass than the most recent cold shot could arrive late in the week.  

Hurricane Sally made landfall near Gulf Shores, AL with maximum sustained winds of 105 mph. So far, Sally has brought 24.80" rain to Escambia, FL and 24.81" to Pensacola Naval Air Station. The ASOS at Pensacola Region Airport was knocked out yesterday evening. A storm report stated, "Landscape and architectural debris found lining the streets of downtown Mobile, AL."

 

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Good Wednesday morning all,  The NAEFS may have been very wrong in it's northward extent of rainfall expectations Friday, with the GFS projecting to be best on this (so far).  However, the SPC HREF is trying to develop showers along the I95 corridor late Thursday (mid level FGEN) so we're not quite done with a rain chance NJ-LI-S CT.

In the meantime,  a post included that I've sent to my family-friends on Smoke projections. 

Continuing the previous theme on West Coast smoke seen in the northeast this Wednesday morning Sept 16. It appears somewhat thinner today. Yet, it may be with us into Friday, but modeled to be less noticeable.
 
High clouds may be arriving this evening but pass above the smoke layer that is generally located between 5000 and 18000 feet aloft. The clouds should be above 20000 feet. Lower clouds (and eventually showers?) will complicate smoke visuals Thursday and Friday. I've added a couple of model forecast smoke graphics.
 
It may be of interest that we get a hint of smelling smoke late Thursday or Thursday night here in parts of the northeast, particularly terrain above 1000 feet elevation.
 
Attached are graphics showing 1) entire smoke plume at 2PM Thursday, then near surface smoke expectations Thursday afternoon at 2PM and Thursday night just after midnight (second and third graphics below from the United States HRRRX model). The last graphic is from a Canadian smoke model. You can see some advance into the northeast. So we'll see how that goes. 846A/16

Screen_Shot_2020-09-16_at_7_39.56_AM.png

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Screen_Shot_2020-09-16_at_7_43.32_AM.png

Screen Shot 2020-09-16 at 7.46.01 AM.png

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Regarding the attached graphics (01z/12):  Birds on radar  or not…

Need to check loops of reflectivity,  the VAD wind profile versus modeled wind below 3000 feet for nighttime migration, and preponderance of 20 DBZ reflectivity near roosting areas (example along lakes). Also against bird migration prediction-example attached graphic.  

To see the birds in the  morning, you'll need to see concentric rings take off during the morning.  But this was a nighttime radar image. I and others typically referenced these radar clutter's as AP.  I don't think it's clear that this was caused by bird migration although the fall bird migration period begins about this time.  I may have more confirmatory information, one way or the other in a few days.

What you can assume from most of the radars, is a mix of clutter, dust, insects, and possibly birds near the radar. The velocity measures dust/moisture etc at the intersected elevation.  Here is a link... examples are provided.https://www.weather.gov/iln/birds.

I've referenced a peer reviewed paper in the the AMS Journal Weather and Forecasting.  

HTTPS://JOURNALS.AMETSOC.ORG/WAF/ARTICLE/13/2/453/38044/DISPLAYS-OF-BIRD-MOVEMENTS-ON-THE-WSR-88D-PATTERNS

 

RESEARCH ARTICLE| 1 JUNE 1998

Displays of Bird Movements on the WSR-88D: Patterns and Quantification* 

Sidney A. Gauthreaux, Jr.; 

 

Carroll G. Belser

Wea. Forecasting (1998) 13 (2): 453–464.

https://doi.org/10.1175/1520-0434(1998)013<0453:DOBMOT>2.0.CO;2

Article history

Abstract

The WSR-88D can readily detect birds in the atmosphere in both clear air and precipitation mode, and echo reflectivities of 30–35 dBZ may be realized during heavy migration events or when birds are departing a roosting site. This paper describes the appearance of birds on base reflectivity, base velocity, and velocity azimuth display wind profile products, and presents a calibration curve that relates decibel values of reflectivity to bird migration traffic rates. The recognition of bird displays in WSR-88D products is essential for the accurate interpretation of data gathered by the radar and its use in the development of forecasts. The findings also document the importance of the WSR-88D as a remote sensing tool for biological studies of birds and insects in the atmosphere and the application of such information in the avoidance of bird–aircraft collisions.

 

It is clear that migrating birds are biasing the winds aloft information generated by the WSR-88D VAD algorithms. The birds so influence the VAD wind profiles that they often can be used to document the altitudinal distribution of the migration (see Haro and Gauthreaux 1997Gauthreaux et al. 1998)

 

 

 

4. Bird roosting movements on the WSR-88D

Outside of the spring and fall migration seasons the WSR-88D readily detects concentrations of birds (and bats) as they depart and return to roost sites. The departures of birds from roost sites at dawn and near sunrise are particularly prominent on base reflectivity products as the radar beam is often bent back toward the ground because of superrefraction. Inversions of temperature and moisture influence the index of refraction of the radar beam in the atmosphere, and these conditions are characteristic of the lower atmosphere near dawn when the birds depart their overnight roost (Russell and Gauthreaux 1998). In contrast, near the time of sunset and dusk normal propagation of the radar beam usually occurs, and the beam is often too high to detect the bird targets returning to the roost unless they are flying at altitudes covered by the radar beam.

 

 

 

Because dense swarms of insects in the atmosphere produce base reflectivity displays that are quite similar to low-density bird migration displays (see Russell and Wilson 1996), it is essential that base velocity information be gathered at the same time as base reflectivity products. With a knowledge of the winds aloft it is possible to distinguish bird movements from insect movements, because the latter have air speeds that rarely, if ever, exceed 8–10 m s−1 (most are between 4 and 6 m s−1) while migrating birds typically fly at speeds greater than 10 m s−1. Because of their low air speeds insects tend to move with the wind, deviating just a few degrees from down wind, whereas birds will sometimes fly against the wind. In general, insect ground speeds exceed corresponding wind speeds by approximately 2–6 m s−1 (Schaefer 1976).

 

The recognition of migrating birds on weather surveillance radar will also clarify many of the misconceptions that television weathermen have about “noisy” or “anomalous” radar patterns that appear on national mosaics. These mosaics usually display reflectivity levels of 20 dBZ and above, because the lower reflectivity levels have been eliminated or filtered out. Despite setting the minimum base reflectivity filters at 20 dBZ, during dense bird migrations, reflectivity values from the mass of migratory birds may reach 20 dBZ levels and even reach 30-dBZ level during the seasonal peak of migration. Such patterns are commonplace at night during the spring and fall migration periods.  918A/16

 

 

1113A added migration news from 9/10-11... was Low-medium in the northeast.  

 

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Screen Shot 2020-09-16 at 11.10.00 AM.png

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1 hour ago, dWave said:

Air quality is still considered good. The smoke is too high to affect air quality at the surface. At least that is the offical forecast. For me the cooler, and espically drier air recently is an asthma trigger. 

my thoughts, too. It was just coincidental timing. 

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48 minutes ago, wdrag said:

Regarding the attached graphics (01z/12):  Birds on radar  or not…

Need to check loops of reflectivity,  the VAD wind profile versus modeled wind below 3000 feet for nighttime migration, and preponderance of 20 DBZ reflectivity near roosting areas (example along lakes). Also against bird migration prediction-example attached graphic.  

To see the birds in the  morning, you'll need to see concentric rings take off during the morning.  But this was a nighttime radar image. I and others typically referenced these radar clutter's as AP.  I don't think it's clear that this was caused by bird migration although the fall bird migration period begins about this time.  I may have more confirmatory information, one way or the other in a few days.

What you can assume from most of the radars, is a mix of clutter, dust, insects, and possibly birds near the radar. The velocity measures dust/moisture etc at the intersected elevation.  Here is a link... examples are provided.https://www.weather.gov/iln/birds.

I've referenced a peer reviewed paper in the the AMS Journal Weather and Forecasting.  

Well, I can confirm it.  When you see that general "bloom" right after sunset, that's the ticket!  In spring and fall, that's birds taking off.  As a bird watcher, I pay close attention to nighttime radar in spring and fall, also wind and precipitation.  Yesterday, September 15, 2020 followed a night of good-looking radar, with the only caveat that there was no precipitation in the NYC-NJ area to get birds to land near daybreak.  Nevertheless, it was a good migration day along the coast with high numbers and variety of migrating birds that landed and foraged until they could take off the following night.  (Most landbirds migrate at night).

The still-to-be-worked out problem is that sometimes - actually more often than not - the radar looks great but the birds are not there in quantity in the morning.  They seem to stay aloft and keep going in clear weather with favorable winds.  Also, again using yesterday as an example, the birds did come down and were foraging all day - but then they took off again that night even though the winds - S rather than NW - were unfavorable.  This too is a "problem" yet to be solved.

 

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7 minutes ago, Cfa said:

Low of 51 here, currently 71.

Looks like ISP made it down to 50°. Getting closer to the average first 40s date of the season since 2010.

First/Last Summary for ISLIP-LI MACARTHUR AP, NY
Each section contains date and year of occurrence, value on that date.
Click column heading to sort ascending, click again to sort descending.
Year
Last
Value
First
Value
Difference
Minimum 05-13 (2011) 09-02 (2017) 85
Mean 05-29 09-20 113
Maximum 06-12 (2018) 10-12 (2018) 131
2019 06-04 (2019) 46 09-19 (2019) 46 106
2018 06-12 (2018) 48 10-12 (2018) 49 121
2017 06-08 (2017) 47 09-02 (2017) 49 85
2016 05-23 (2016) 49 09-25 (2016) 48 124
2015 05-23 (2015) 48 10-02 (2015) 49 131
2014 06-01 (2014) 49 09-23 (2014) 45 113
2013 05-28 (2013) 48 09-09 (2013) 49 103
2012 06-06 (2012) 49 09-17 (2012) 49 102
2011 05-13 (2011) 47 09-19 (2011) 49 128
2010 05-20 (2010) 49 09-16 (2010) 47 118
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GFS up to its old tricks again as it shows 10-straight days in the 80's and up to 93*, starting the 23rd.         Its ensemble has no 80's.        It is still devoid of precipitation.         9/27 changes by +30 from yesterday's 12Z to today's 12Z.

Asking for a BN Sept. or Oct. during the last 10 years has been futile, just 1 BN month out of 20----and that by just 0.1 degrees!.

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