question - weather operations

[chuckschick]

Heard on the news last night that KBOS was briefly "closed" because of weather. I have no idea if that was accurate or what it meant, but my question is: other than obvious conditions such as snow or thunderstorms, what conditions would cause Logan (or other major airports) to close for arrivals?

Can't the ILS runways accommodate poor visibility and can't planes land in near zero-visibility with a category III ILS? Is 4R the only runway with a category III ILS, so if the winds were blowing the wrong way, the airport would be closed for arrivals?

[KSYR-pjr]

Other than snow or thunderstorms?   Hmmm... A hurricane or other deep low pressure storm (Boston gets a lot of coastal storms), dust storms, volcanic ash, an airplane crash on the airport grounds, strong wind shear, and terrorism threat come to mind.

I would speculate that last evening's temporary closure would have been thunderstorm or very heavy rain related.  However in my experience wind shear and hail are a bigger threat to an aircraft landing during a tstorm than low visibility caused by rain.

edit:  Even a CAT III-equipped aircraft is not immune to the effects of wind shear or hail.

[chuckschick]

Other than snow or thunderstorms?   Hmmm... A hurricane or other deep low pressure storm (Boston gets a lot of coastal storms), dust storms, volcanic ash, an airplane crash on the airport grounds, strong wind shear, and terrorism threat come to mind.

I would speculate that last evening's temporary closure would have been thunderstorm or very heavy rain related.  However in my experience wind shear and hail are a bigger threat to an aircraft landing during a tstorm than low visibility caused by rain.

edit:  Even a CAT III-equipped aircraft is not immune to the effects of wind shear or hail.

That's why I was curious - I didn't notice any major weather last night, no thunderstorms or wind (I live about 10 miles from the field). Nor volcanic ash or crash which would have been in the paper. So I was wondering what visibility conditions might cause a closure.

[KSYR-pjr]

Okay, I had assumed that cold front that swung through New England set off some t-storms but in looking at the METAR history of Boston over the last 36 hours I don't see any real adverse weather, or at least anything worthy of closing the airport.

To see up to a 36 hour METAR history of US airports with weather reporting equipment click here, provide the ICAO airport ID and drop down the history box to see more than the current observation: 

http://adds.aviationweather.noaa.gov/metars/

Here are the METARS from KBOS during the evening yesterday.  Again, I don't see anything too crazy there (the +RA stands for heavy rain, but there are no indications of thunderstorms or wind shear in any of these):

Code: [Select]

KBOS 282354Z 10006KT 3SM -RA BR OVC006 11/11 A2983 RMK AO2 SLP100 P0005 60027 T01110106 10111 20072 56025
KBOS 282338Z 10006KT 5SM -RA BR OVC006 11/11 A2983 RMK AO2 P0004
KBOS 282300Z 09005KT 2SM RA BR FEW003 OVC006 11/11 A2984 RMK AO2 P0001
KBOS 282254Z 08005KT 4SM -RA BR FEW003 OVC006 11/11 A2984 RMK AO2 SLP106 P0002 T01110106
KBOS 282220Z 10005KT 4SM -RA BR OVC006 11/11 A2986 RMK AO2 P0001
KBOS 282201Z 10005KT 2 1/2SM -RA BR OVC008 11/11 A2987 RMK AO2 P0001
KBOS 282154Z 10007KT 1 3/4SM -RA BR BKN008 OVC015 10/10 A2988 RMK AO2 TWR VIS 2 SLP116 P0006 T01000100
KBOS 282145Z 11009KT 1 3/4SM R04R/5500VP6000FT +RA BR BKN008 OVC015 10/09 A2988 RMK AO2 TWR VIS 2 P0003
KBOS 282112Z 10009KT 6SM -RA BR BKN008 OVC020 09/09 A2989 RMK AO2 P0001
KBOS 282054Z 09010KT 6SM -RA BR BKN010 OVC022 09/08 A2990 RMK AO2 SLP125 P0001 60014 T00940083 58037
KBOS 281954Z 10010KT 5SM -RA BR BKN012 OVC025 08/08 A2995 RMK AO2 SLP140 P0004 T00830078
KBOS 281854Z 11013KT 9SM -RA FEW009 BKN012 OVC025 08/07 A2999 RMK AO2 PK WND 11027/1812 SLP154 P0009 T00780067
KBOS 281843Z 11017G22KT 8SM -RA SCT007 OVC012 08/07 A2999 RMK AO2 PK WND 11027/1812 P0009
KBOS 281824Z 11017KT 2SM R04R/6000VP6000FT -RA BR BKN009 OVC012 08/07 A2999 RMK AO2 PK WND 11027/1812 SFC VIS 4 CIG 007V012 P0006
KBOS 281809Z 11016G22KT 3SM -RA BR SCT007 OVC012 07/06 A3000 RMK AO2 P0005
KBOS 281754Z 11018G26KT 1 3/4SM R04R/5500VP6000FT +RA BR SCT006 OVC014 07/06 A3001 RMK AO2 PK WND 10026/1753 SLP162 P0007 60022 T00720056 10094 20072 57030
Assuming you knew the approximate time of this closure why not retrieve LiveATC's archives for Boston to see what the controllers and pilots were saying right up until the time they held off aircraft?   Then again, given that this event was reported in the TV medium who knows what the real reason was? 

[Teller1900]

Not all planes/operators are CAT III equipped or certified.  That said, ceilings/vis have been causing a lot of delays this last week in BOS, but they haven't been THAT low.  What I'd bet is A) lightening reported on or near the field, B) windsheer/svr turb reported on approach or departure from the field (with the rain and wind in those METARs, that'd be my bet), or C) one of the many many airfield maintenance guys out working messed something up  . 

We reported +-35 kts with continuous moderate to severe turbulence from the surface to 3,000 on climbout from BOS a month or so ago.  Come to find out, three planes (including one from our company who heard our report/told me this story) on the approach were spun and held for a half hour, everyone else on vectors was tucked into a corner somewhere, and all departures were halted for a half an hour.   

I think it'd be pretty hard for the ceiling/vis to be low enough for them to close the airport; they just use low visibility taxi procedures, and anyone who can't start the approach is held.  Lots of people might go missed, but I'd be surprised if they close the airport (ground stop, sure; closure, probably not).