0 vis +SN at JFK/HPN

[Ian]

I'm not sure I ever remember seeing 0 vis in a snow METAR (at northeast populated location).. it can't be that common.

METAR KJFK 270151Z COR 34034G42KT 0SM R04R/1600V2200FT +SN FZFG BLSN VV001 M06/M07 A2921 RMK AO2 PK WND 35048/0140 SFC VIS 1/8 PRESFR SLP891 SNINCR 1/6 P0003 T10561072 $

METAR KHPN 270156Z 34030G41KT 0SM SN BLSN VV002 M08/M10 A2923 RMK AO2 PK WND 34041/0155 PRESFR SLP909 P0004 T10781100 $

[tornadotony]

I'm not sure I ever remember seeing 0 vis in a snow METAR (at northeast populated location).. it can't be that common.

METAR KJFK 270151Z COR 34034G42KT 0SM R04R/1600V2200FT +SN FZFG BLSN VV001 M06/M07 A2921 RMK AO2 PK WND 35048/0140 SFC VIS 1/8 PRESFR SLP891 SNINCR 1/6 P0003 T10561072 $

METAR KHPN 270156Z 34030G41KT 0SM SN BLSN VV002 M08/M10 A2923 RMK AO2 PK WND 34041/0155 PRESFR SLP909 P0004 T10781100 $

I don't think it can be that common at all period. We recently saw one at Gary, IN (KGYY) during the blizzard on December 12th with +SN and a 63 MPH gust on an hourly report, but I don't remember the last time I saw 0SM before that...

[ayuud]

wow! http://www.earthcam....rk/timessquare/

http://www.earthcam.com/usa/newyork/timessquare/?cam=fridays

[tornadotony]

I don't think it can be that common at all period. We recently saw one at Gary, IN (KGYY) during the blizzard on December 12th with +SN and a 63 MPH gust on an hourly report, but I don't remember the last time I saw 0SM before that...

It was actually 2 consecutive hourlies of 0SM during that blizzard...

[Ian]

i attached a radar

[ayuud]

you could actually hear some thunder on the web cam link i posted above^

[afvet89]

I work with augmenting ASOS Metar obs at my job and have never put in 0sm. Whenever we get +SN, it was always M(less than)1/4sm+SN. Wish I was there for this one.

[eyewall]

Thundersnow in this one! Start it at 1:50

[dendrite]

Yeah...you can't get 0SM with the automation nowadays. I've seen 0SM from some of the NYC stations a few times over the last decade...some snow and some just pea soup fog. But as the others said it has to be augmented in by an observer.

ASOS struggles to report M1/4SM on its own as well. Usually the lowest you see is 1/4SM although you occasionally see M1/4SM when the snow is very heavy.

[Ian]

lots and lots of reports of tsnow it seems.. epic band

[forkyfork]

i live just west of the j in jersey city, not far from the morris county border

i have yet to experience tsnow

[Ian]

twitter search on thunder snow.. lots of nyc ppl excited about it

http://twitter.com/search?q=thunder%20snow

[afvet89]

Yeah...you can't get 0SM with the automation nowadays. I've seen 0SM from some of the NYC stations a few times over the last decade...some snow and some just pea soup fog. But as the others said it has to be augmented in by an observer.

ASOS struggles to report M1/4SM on its own as well. Usually the lowest you see is 1/4SM although you occasionally see M1/4SM when the snow is very heavy.

That is exactly right,. Any value less than 1/4 , ex.0,1/16, or 1/8 must be augmented manually. Also, fyi, 0,1/8, and 1/16 are the only reportable vis values below 1/4. So to put 0 as the visibility must really be impressive to the wx observers there.

[wxnut]

I understand the 0 vsby in heavy snow and blowing snow.. what I don't get is why FZFG is in the obs? There's no fog in a raging blizzard..

[Kmlwx]

I understand the 0 vsby in heavy snow and blowing snow.. what I don't get is why FZFG is in the obs? There's no fog in a raging blizzard..

The automated machine doesn't know though. You see that a lot with heavy snow reports.

[winterymix]

weird stuff

NANTUCKET LGT RAIN 40 38 93 NE29G41 28.98F FOG WCI 29

KENNEDY INTL SNOW 22 19 89 N43G56 29.17F VSB 0 WCI 1

[afvet89]

When the vis drops below 5/8, then the ASOS automatically adds FG or FZFG. I have never removed this obscuration nor have I seen any other worker at the diff facilities I have worked at remove it.

[Amped]

I'm not sure I ever remember seeing 0 vis in a snow METAR (at northeast populated location).. it can't be that common.

METAR KJFK 270151Z COR 34034G42KT 0SM R04R/1600V2200FT +SN FZFG BLSN VV001 M06/M07 A2921 RMK AO2 PK WND 35048/0140 SFC VIS 1/8 PRESFR SLP891 SNINCR 1/6 P0003 T10561072 $

METAR KHPN 270156Z 34030G41KT 0SM SN BLSN VV002 M08/M10 A2923 RMK AO2 PK WND 34041/0155 PRESFR SLP909 P0004 T10781100 $

Snow accumulated on the lense of the sensor. (My Guess)

[afvet89]

just one more thing just to clarify, when vis drops below 7 sm, a descriptor must be present . For example, if u have vis 6sm then u should have an obscuration , like haze or mist or fog. So on a metar u would see 6sm HZ (haze)or 6 sm BR(mist). Then when vis drops below 5/8 it would change to FG.SNOW is considered precipitation and not an obscuration hence the need for FG,BR, HZ once the vis drops below 7sm.. Altho I would argue that Sn is def an obscuration.Hope I didnt confuse anyone. I stink at explaining things.

[friendwh]

I think we've officially seen 3 hours of blizzard conditions at KHPN...

[bronxx]

Thundersnow in this one! Start it at 1:50

Excellent, excellent video. Great videography and even more so, great depiction of NYC residents reactions in the harsh weather conditions. Whoever shot this is either a professional or just has great journalistic video instincts.

The photographer knew very well to catch the subjects and their reactions to their unusual surroundings, and to not make himself the center point of the story; totally the opposite of how many supposed storm-chaser types shoot their videos.

[Mencken_Fan]

When I was stationed at King Salmon NORAD Control Center in Southwest Alaska we had to hand write hourly METARs backwards from the back side of our clear acrylic weather status board so it would look normal from the front. (METARS, civilian flight plans, etc. all came in via a teletype machine.)

We posted the weather status for all interceptor bases, and during snowstorms I'd sometimes post 1/4 or 1/8 visibility and on the rarest of occasions 1/16....but I never posted a 0 visibility.

I suspect even jaded New Yorkers are looking at this storm with open jaws.

P.S. During that bitterly cold Alaskan winter of '72 we posted "M" for dew points countless times, e.g. -30/M, -45/M, -60/M, etc. (I believe the most extreme report of the winter was -70/M at McGrath bomber base in west central Alaska.)

[Amped]

Mahway NJ had 4.5 at 6PM and 17 at 9:30 PM. 12.5 in 3.5 hours.

Not Sure I believe this 100% but they were in the heart of the band.

[wxnut]

just one more thing just to clarify, when vis drops below 7 sm, a descriptor must be present . For example, if u have vis 6sm then u should have an obscuration , like haze or mist or fog. So on a metar u would see 6sm HZ (haze)or 6 sm BR(mist). Then when vis drops below 5/8 it would change to FG.SNOW is considered precipitation and not an obscuration hence the need for FG,BR, HZ once the vis drops below 7sm.. Altho I would argue that Sn is def an obscuration.Hope I didnt confuse anyone. I stink at explaining things.

Well explained. Thanks. And I agree with your comment that snow can be an obscuration to visibility... just like heavy rain can be. Have the people making these rules never experienced heavy snow or rain?

[wxnut]

One other thing.. wouldn't BLSN be considered an obstruction to visibility? If so, then the observer should remove the FZFG if there's BLSN since the blowing snow is reducing the vsby, not fog.

[Stebo]

One other thing.. wouldn't BLSN be considered an obstruction to visibility? If so, then the observer should remove the FZFG if there's BLSN since the blowing snow is reducing the vsby, not fog.

Its one or the other, not both, they have both in their obs which is incorrect as its a double obscuration. That would be like saying you have mist and haze at the same time.

[yak]

Excellent, excellent video. Great videography and even more so, great depiction of NYC residents reactions in the harsh weather conditions. Whoever shot this is either a professional or just has great journalistic video instincts.

The photographer knew very well to catch the subjects and their reactions to their unusual surroundings, and to not make himself the center point of the story; totally the opposite of how many supposed storm-chaser types shoot their videos.

Totally agree and only a real professional could have anticipated thundersnow. A top nominee for tomorrow's viral video and whether or not he was cognizant of the viewing audience at the time, I loved the kindness in this video.

I also loved the way the thundersnow elicited a collective gasp even from New Yorkers. If you've never experienced it, it is a truely memorable experience that millions of New Yorkers probably had this evening. Kudos on the storm and the video.

[Chagrin Falls]

The JFK METAR has tower visibility in the body of the report. High elevation ATC Towers like JFK do report 0SM at times if they are in the clouds, heavy precip, etc. ATL, MCO, LAX comes to mind with fog. The surface visibility was 1/8SM. I think the JFK tower is over 300 ft high.

HPN has "weather observer issues". Their observations are handled by airport operations and while they are certified weather observers HPN is not a contract weather office like most augmented ASOS. Same thing at TEB.

I think OKX has even acknowledged the accuracy of some weather observations at places like HPN & SWF.

[meridian]

I'm not sure I ever remember seeing 0 vis in a snow METAR (at northeast populated location).. it can't be that common.

METAR KJFK 270151Z COR 34034G42KT 0SM R04R/1600V2200FT +SN FZFG BLSN VV001 M06/M07 A2921 RMK AO2 PK WND 35048/0140 SFC VIS 1/8 PRESFR SLP891 SNINCR 1/6 P0003 T10561072 $

METAR KHPN 270156Z 34030G41KT 0SM SN BLSN VV002 M08/M10 A2923 RMK AO2 PK WND 34041/0155 PRESFR SLP909 P0004 T10781100 $

The slant range observed from the control tower is always worse in these conditions. Notice the measuring equipment for runway 4R is showing approx 1/4 mile. That's probably more accurate.