September 2023

[the_other_guy]

5 hours ago, nycwinter said:

in the old days it was the actual temps that determined how hot it was  now people today are combining the heat and humidity to make it seem the actual temps are much higher ....traditional values are slipping away..

Sensationalist BS. You would have thought the hurricane last week was an Andrew redux headed for downtown Tampa.

Everything has to be greater than it is, when what it is is great enough in terms of historic weather. Oh well.

100 today!! Except it hasnt hit 100 in a very long time because we are too humid to hit 100 now (thats the historic part but not as sexy)

 

[Allsnow]

That hurricane next week is for the fish. All the hype is click bait 

[the_other_guy]

1 minute ago, Allsnow said:

That hurricane next week is for the fish. All the hype is click bait 

Absolutely. Looking at grazing NS haha

[wdrag]

Was thinking a topic for widespread 2-5" rainfall with isolated 10" would be some of value for the period 00z/8-00z/15 but held off due to FFG, ensemble river stage forecasts being conservative.  Still,  I think by the time next Thursday night comes around, isolated life threatening flooding-infrastruture damage will have occurred in the NYC subforum due to repeated 1-4 hour R+ events.  Enough spacing between events permits the recovery needed to probably forego widespread flood damage problems but needs monitoring. This pattern between tonight -Monday, and then reenergized by northward moving Lee interactions with the UL jet Ohio Valley to Bay of Fundy next Wed-Thu is going to result in some significant problems. Where/when is more of a question for me.

Fairly certain damaging wet microburst severe embedded-so monitoring SPC/local office statements is worthy.

On Lee:  if it crosses 70W as it comes around the western Atlantic ridge ahead of the uncertain amplitude of the approaching 5H trough middle of next week, then a New England scraper would be possible.   Lots of uncertainty on the shape of the approaching trough middle of next week. 

Added WPC 7 day contoured forecast issued early this Thursday morning 9/7/23

[psv88]

Low of 80 at LGA on September 7. Has to be a record?

[forkyfork]

7 minutes ago, psv88 said:

Low of 80 at LGA on September 7. Has to be a record?

that breaks the previous record high min by 6 degrees if there's no convection later

[Allsnow]

The rain the next few days looks to be nw of the the coast. Similar set up to last July when the focus was eastern Pa and nw jersey 

[bluewave]

5 hours ago, nycwinter said:

in the old days it was the actual temps that determined how hot it was  now people today are combining the heat and humidity to make it seem the actual temps are much higher ....traditional values are slipping away..

Consistent extreme dew points and heat indices didn’t really become more frequent around until July 1995.

 

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=76&network=NY_ASOS&station=ISP&season=summer&varname=dwpf&agg=mean&year=1893&w=bar&hours=0-23&_r=t&dpi=100&_fmt=png

 

[Rtd208]

Temps rising quckly this morning.

Current temp 88/DP 74/RH 65%

[Allsnow]

1 hour ago, bluewave said:

Those point forecasts can be off by 10-20 miles in determining where the max sets up around Philly. So the upper 90s maxes around Philly have been spot on in the city center. Same goes for NJ. The coarse model resolution often shows the max temperatures 20-30 miles SW of Newark and Harrison. But the maxes are usually further NE. So I take the Euro NJ state temperature max and adjust it closer to the urban corridor around Newark. 

Per Rainshadow (retired NWS met) “generally speaking center city should be hotter than the airport but the verification point is the airport. The USCG site in center Philly reached 95 yesterday. The Franklin institute has their instrument shelter on the roof. That is the wrong exposure. The wegmans parking lot is hotter if the instrument was on a grassy median. The euro is broad brushing upper 90’s up and down 95 when in reality that isn’t the case” 

[Juliancolton]

I'm being robbed of a heatwave. Highs 90, 90, 89, 91 the last four days.

[doncat]

Just now, Allsnow said:

This why the meso sites can’t be trusted 

Yeah don't know when it became acceptable to use rooftop stations as official but several in the local mesonets are. Of course we have the problem of improperly sited pws also.

[donsutherland1]

This morning's low temperature at LaGuardia Airport was 80°. If that low holds, it would be the latest 80° or above low on record for the New York City area (Central Park, JFK Airport, or LaGuardia Airport). The record is September 4, 2018 at LaGuardia Airport.

[Allsnow]

Either way you slice it, this is the hottest week of the summer and it does feel like July 

[Allsnow]

1 minute ago, doncat said:

Yeah don't know when it became acceptable to use rooftop stations as official but several in the local mesonets are. Of course we have the problem of improperly sited pws also.

Especially when the verification site has a proper setup 

[bluewave]

4 minutes ago, Allsnow said:

Per Rainshadow (retired NWS met) “generally speaking center city should be hotter than the airport but the verification point is the airport. The USCG site in center Philly reached 95 yesterday. The Franklin institute has their instrument shelter on the roof. That is the wrong exposure. The wegmans parking lot is hotter just like the tarmac at ewr. Does that mean nyc is to cold? The euro is broad brushing upper 90’s up and down 95 when in reality that isn’t the case” 

You are mixing several things together. First,Tony is correct that the city center is warmer than the airports. Philly is in a swamp next to the Delaware River. So it’s not the greatest representation of the actual temperatures in Philly. I am not a fan of rooftop sites, but it’s not necessarily that they are biased warm vs ground level. Just look at the warmest temperatures in the NYC micronet. The street level sites are often the same or even warmer than rooftop. Plus the higher the rooftop site, the cooler the temperatures. So high enough can be introducing a cool bias. Newark is not significantly warmer than say Harrison or Freehold. NYC is definitely too cold since it’s the only US observing site under a dense tree canopy which biases the highs 2-5 degrees too cool. This wasn’t the case when the site received direct exposure before the 1990s. This was when NYC was typically warmer than LGA as mentioned but the NWS at the time. Ever wonder why the heatwaves before the 1990s had Central Park near the leader for high summer temperatures? Go measure the highs out on the Great Lawn and you would see this cool bias of the trees disappear. 

[MANDA]

2 minutes ago, Allsnow said:

Either way you slice it, this is the hottest week of the summer and it does feel like July 

Agreed!  Thankfully the September sun angle helps a little, would have felt worse with a July sun angle.  Impressive though.

[Allsnow]

6 minutes ago, bluewave said:

You are mixing several things together. First,Tony is correct that the city center is warmer than the airports. Philly is in a swamp next to the Delaware River. So it’s not the greatest representation of the actual temperatures in Philly. I am not a fan of rooftop sites, but it’s not necessarily that they are biased warm vs ground level. Just look at the warmest temperatures in the NYC micronet. The street level sites are often the same or even warmer than rooftop. Plus the higher the rooftop site, the cooler the temperatures. So high enough can be introducing a cool bias. Newark is not significantly warmer than say Harrison or Freehold. NYC is definitely too cold since it’s the only US observing site under a dense tree canopy which biases the highs 2-5 degrees too cool. This wasn’t the case when the site received direct exposure before the 1990s. This was when NYC was typically warmer than LGA as mentioned but the NWS at the time. Ever wonder why the heatwaves before the 1990s had Central Park near the leader for high summer temperatures? Go measure the highs out on the Great Lawn and you would see this cool bias of the trees disappear. 

Great post. Thanks 

[uofmiami]

10 minutes ago, bluewave said:

Go measure the highs out on the Great Lawn and you would see this cool bias of the trees disappear. 

It'd be great if we had real time to compare but it'll never happen unfortunately.  Have to go on former location data to current location data.

[forkyfork]

ewr is already 90 

[Neblizzard]

1 hour ago, Allsnow said:

That hurricane next week is for the fish. All the hype is click bait 

Most Mets and others have agreed this would be a fish storm. I don’t see any hype about an east coast strike 

[psv88]

Absolutely roasting this morning. 90/77 already. Yesterday at this time I was only 86. North winds definitely kept north shore a little cooler yesterday. 

[bluewave]

19 minutes ago, Allsnow said:

Great post. Thanks 

You can see from this old NYT article how Central Park used to be warmer than LGA when the instruments weren’t under the trees. The ASOS at LGA is right on the water away from the main terminals and taxiways. So they can easily get wind flow off that western portion off the Sound-East River. 

https://www.nytimes.com/1977/07/22/archives/vandals-in-central-park-forcing-weather-service-to-seek-new-site.html

[psv88]

12 minutes ago, bluewave said:

You can see from this old NYT article how Central Park used to be warmer than LGA when the instruments weren’t under the trees. The ASOS at LGA is right on the water away from the main terminals and taxiways. So they can easily get wind flow off that western portion off the Sound-East River. 

https://www.nytimes.com/1977/07/22/archives/vandals-in-central-park-forcing-weather-service-to-seek-new-site.html

Yea, that has kept LGA relatively cool this week. Constant flow off the sound. You can even see some of the wind obs showing a NE wind direction at LGA and NYC off the sound, when the rest of the area has a west/nw wind. 

[SACRUS]

 

10AM ROundup

 

 

EWR: 90
New Brnswck: 89
LGA: 87
NYC: 86
JK: 86
 

[SACRUS]

 

 

 

[forkyfork]

ewr is probably going to get a seabreeze later this afternoon. the little compressional boost ahead of it could be enough for 100

[Rjay]

88 here with winds off the water

[rclab]

1 hour ago, Juliancolton said:

I'm being robbed of a heatwave. Highs 90, 90, 89, 91 the last four days.

 

Good morning Julian. At least you still have you pants and you can contact Will if you need the theft investigated. Stay cool, as always ….

[dWave]

90 dew 70 now, after a low of 79.