October Lake Effect Snow October Lake Effect Snow in Renoin Reno

Gina McGuireGina McGuire

What happened on October 10, 2008 in What happened on October 10, 2008 in Reno/Sparks?Reno/Sparks?

• Lake effect snow was expected and did develop off of both Lake effect snow was expected and did develop off of both Pyramid Lake and Lake Tahoe on Oct. 10Pyramid Lake and Lake Tahoe on Oct. 10thth

• A Winter Weather Advisory was issued for the Reno zone A Winter Weather Advisory was issued for the Reno zone between 6am and 6pm (for 1-2 inches of snow)between 6am and 6pm (for 1-2 inches of snow)

• Lake Effect Snow Advisory was issued for Lake Tahoe Lake Effect Snow Advisory was issued for Lake Tahoe between 11am and 11pm (for 2 to 6 inches of snow)between 11am and 11pm (for 2 to 6 inches of snow)

• The main airport affected was Reno International Airport, as The main airport affected was Reno International Airport, as the flow was more northeast over the lakesthe flow was more northeast over the lakes

• TVL was only impacted minimally and for a short durationTVL was only impacted minimally and for a short duration

• This presentation will focus on RenoThis presentation will focus on Reno

Reno TAFsReno TAFs

• KRNO KRNO 101120Z101120Z 101212101212 35010KT P6SM SCT060 BKN150 35010KT P6SM SCT060 BKN150 FM1600 35012G20KT P6SM -SHSN SCT030 BKN040 FM1600 35012G20KT P6SM -SHSN SCT030 BKN040 TEMPO 1720 2SM -SHSN BKN020 OVC030 TEMPO 1720 2SM -SHSN BKN020 OVC030 FM2300 36014KT P6SM SCT050 BKN080 FM2300 36014KT P6SM SCT050 BKN080 FM0500 32007KT P6SM VCSH OVC040FM0500 32007KT P6SM VCSH OVC040

• KRNO 101155Z 35009KT 10SM SCT065 02/M08 A2992 RMK A02 SLP120 KRNO 101155Z 35009KT 10SM SCT065 02/M08 A2992 RMK A02 SLP120 T00171078 10056 20011 56016=T00171078 10056 20011 56016=

So, what happens at 14Z??So, what happens at 14Z??

• KRN0 101355Z 34011G18KT 10SM –SN BKN046 OVC065 01/M06 A2991 KRN0 101355Z 34011G18KT 10SM –SN BKN046 OVC065 01/M06 A2991 RMK A02 SNB52 SLP121 P0000 T00111061=RMK A02 SNB52 SLP121 P0000 T00111061=

What would you do with the forecast right now… if anything?What would you do with the forecast right now… if anything?

The TAF was revised…The TAF was revised…• KRNO KRNO AMDAMD 101405Z 101412101405Z 101412 35012G20KT P6SM -SHSN SCT030 35012G20KT P6SM -SHSN SCT030

BKN040 BKN040 TEMPO 1418 3SM -SHSN BKN020 OVC030 TEMPO 1418 3SM -SHSN BKN020 OVC030 FM2300 36014KT P6SM SCT050 BKN080 FM2300 36014KT P6SM SCT050 BKN080 FM0500 32007KT P6SM VCSH OVC040FM0500 32007KT P6SM VCSH OVC040

What happened between 14Z and 18Z?What happened between 14Z and 18Z?

• KRNO KRNO 101455Z101455Z 34012G20KT 10SM HZ BKN047 OVC055 01/M06 A2992 RMK 34012G20KT 10SM HZ BKN047 OVC055 01/M06 A2992 RMK AO2 SNE02B23E48 SLP125 MTN TOPS OBSCD SW-NW P0000 60000 AO2 SNE02B23E48 SLP125 MTN TOPS OBSCD SW-NW P0000 60000 T00061056T00061056

• KRNO KRNO 101555Z101555Z 31013KT 9SM BKN050 OVC070 02/M06 A2993 RMK AO2 31013KT 9SM BKN050 OVC070 02/M06 A2993 RMK AO2 SNB04E53 SLP134 MTNS OBSCD SW-NW P0000 T00171061=SNB04E53 SLP134 MTNS OBSCD SW-NW P0000 T00171061=

• KRNO KRNO 101655Z101655Z 36010KT 10SM SCT050 BKN070 OVC100 03/M07 A2994 RMK 36010KT 10SM SCT050 BKN070 OVC100 03/M07 A2994 RMK AO2 SLP134 VCSH MTNS OBSCD SW-NW T00331067=AO2 SLP134 VCSH MTNS OBSCD SW-NW T00331067=

• KRNO KRNO 101755Z101755Z 34008KT 10SM -SN BKN040 OVC050 02/M07 A2995 RMK AO2 34008KT 10SM -SN BKN040 OVC050 02/M07 A2995 RMK AO2 SNB51 SLP142 MTNS OBSCD ALQDS P0000 60000 T00221067 10033 SNB51 SLP142 MTNS OBSCD ALQDS P0000 60000 T00221067 10033

Good amendment or unnecessary?Good amendment or unnecessary?

Time to issue 18Z TAF…Time to issue 18Z TAF…

What was happening when this TAF was issued??What was happening when this TAF was issued??

• KRNO KRNO 101655Z101655Z 36010KT 10SM SCT050 BKN070 OVC100 03/M07 A2994 36010KT 10SM SCT050 BKN070 OVC100 03/M07 A2994 RMK AO2 SLP134 VCSH MTNS OBSCD SW-NW T00331067=RMK AO2 SLP134 VCSH MTNS OBSCD SW-NW T00331067=

• KRNO KRNO 101755Z101755Z 34008KT 10SM -SN BKN040 OVC050 02/M07 A2995 RMK 34008KT 10SM -SN BKN040 OVC050 02/M07 A2995 RMK AO2 SNB51 SLP142 MTNS OBSCD ALQDS P0000 60000 T00221067 10033AO2 SNB51 SLP142 MTNS OBSCD ALQDS P0000 60000 T00221067 10033

What did the radar look like at 1740Z when the TAF needed to be issued?What did the radar look like at 1740Z when the TAF needed to be issued?

What would you put in the 18Z TAF??What would you put in the 18Z TAF??

Here’s the TAF that was issued… agree/disagree?Here’s the TAF that was issued… agree/disagree?

• KRNO KRNO 101724Z 101818101724Z 101818 33012G20KT P6SM -SHSN BKN035 BKN050 33012G20KT P6SM -SHSN BKN035 BKN050 TEMPO 1822 3SM -SHSN BKN020 OVC030 TEMPO 1822 3SM -SHSN BKN020 OVC030FM2300 01015G24KT P6SM -SHSN BKN040 FM2300 01015G24KT P6SM -SHSN BKN040 FM0300 32007KT P6SM VCSH OVC040 FM0300 32007KT P6SM VCSH OVC040 FM0600 34009KT P6SM VCSH BKN040 OVC080 FM0600 34009KT P6SM VCSH BKN040 OVC080 FM1400 32015KT P6SM SCT050 BKN120FM1400 32015KT P6SM SCT050 BKN120

So, what happened after the TAF was issued?So, what happened after the TAF was issued?

• KRNO KRNO 101755Z101755Z 34008KT 10SM -SN BKN040 OVC050 02/M07 A2995 RMK AO2 34008KT 10SM -SN BKN040 OVC050 02/M07 A2995 RMK AO2 SNB51 SLP142 MTNS OBSCD ALQDS P0000 60000 T00221067 10033SNB51 SLP142 MTNS OBSCD ALQDS P0000 60000 T00221067 10033

• KRNO KRNO 101802Z101802Z 35008KT 9SM BKN027 OVC034 02/M07 A2995 RMK AO2 35008KT 9SM BKN027 OVC034 02/M07 A2995 RMK AO2 SNE1757 P0000=SNE1757 P0000=

• KRNO KRNO 101813Z101813Z 01011KT 2 1/2SM -SN BKN023 OVC036 02/M04 A2996 RMK AO2 01011KT 2 1/2SM -SN BKN023 OVC036 02/M04 A2996 RMK AO2 P0000=P0000=

• KRNO KRNO 101815Z101815Z 01008KT 1 1/4SM -SN BKN020 01/M03 A2996 RMK AO2 P0000= 01008KT 1 1/4SM -SN BKN020 01/M03 A2996 RMK AO2 P0000=

• KRNO KRNO 101821Z101821Z 02007KT 1/2SM SN VV015 01/M02 A2996 RMK AO2 P0000= 02007KT 1/2SM SN VV015 01/M02 A2996 RMK AO2 P0000=

Based on the radar, was this a surprise? Why?Based on the radar, was this a surprise? Why?

What’s the next step?What’s the next step?

Time to amend!Time to amend!

• KRNO KRNO AMD 101822Z 101818AMD 101822Z 101818 33012G20KT 2SM -SHSN VV015 33012G20KT 2SM -SHSN VV015 TEMPO 1822 1/2SM SHSN VV008 TEMPO 1822 1/2SM SHSN VV008 FM2300 01015G24KT P6SM -SHSN BKN040 FM2300 01015G24KT P6SM -SHSN BKN040 FM0300 32007KT P6SM VCSH OVC040 FM0300 32007KT P6SM VCSH OVC040 FM0600 34009KT P6SM VCSH BKN040 OVC080 FM0600 34009KT P6SM VCSH BKN040 OVC080 FM1400 32015KT P6SM SCT050 BKN120FM1400 32015KT P6SM SCT050 BKN120

Let’s see how the radar looked from 18Z-22Z…Let’s see how the radar looked from 18Z-22Z…

Let’s see what the METARs showedLet’s see what the METARs showed

• KRNO KRNO 101855Z101855Z 03007KT 1/2SM SN FG FEW007 OVC011 00/M02 A2997 03007KT 1/2SM SN FG FEW007 OVC011 00/M02 A2997 RMK AO2 TWR VIS 1 1/4 SLP152 P0002 T00001017=RMK AO2 TWR VIS 1 1/4 SLP152 P0002 T00001017=

• KRNO KRNO 101955Z101955Z 31006KT 1/2SM SN FG BKN005 OVC010 00/M01 A2997 31006KT 1/2SM SN FG BKN005 OVC010 00/M01 A2997 RMK AO2 SLP153 P0002 T00001011=RMK AO2 SLP153 P0002 T00001011=

• KRNO KRNO 102055Z102055Z 00000KT 1/2SM -SN BR BKN007 OVC013 00/M01 A2996 00000KT 1/2SM -SN BR BKN007 OVC013 00/M01 A2996 RMK AO2 SFC VIS 1 SLP150 P0003 60007 T00001011 58003=RMK AO2 SFC VIS 1 SLP150 P0003 60007 T00001011 58003=

• KRNO KRNO 102155Z102155Z 35006KT 10SM SCT011 BKN028 OVC065 02/M01 A2995 35006KT 10SM SCT011 BKN028 OVC065 02/M01 A2995 RMK AO2 SNE41 SLP146 MTN TOPS OBSCD ALQDS P0001 T00221011=RMK AO2 SNE41 SLP146 MTN TOPS OBSCD ALQDS P0001 T00221011=

• Verdict?? Good or bad amendment?? Verdict?? Good or bad amendment??

• Good!Good!

• What did it look like outside during this time???What did it look like outside during this time???

Pyramid Highway and McCarrenPyramid Highway and McCarren

Reno NWS OfficeReno NWS Office

Picnic Table at NWS Reno overlooking the Reno Picnic Table at NWS Reno overlooking the Reno AirportAirport

•Now it’s time for the 00Z TAF…what did the radar look like at Now it’s time for the 00Z TAF…what did the radar look like at 2340Z?2340Z?

• What did you observe about the radar image?What did you observe about the radar image?

• What would you have put in the 00Z TAF?What would you have put in the 00Z TAF?

• Here’s the 00Z TAF..Here’s the 00Z TAF..

• KRNO KRNO 102320Z 110024102320Z 110024 01010KT 2SM -SHSN BKN012 BKN025 01010KT 2SM -SHSN BKN012 BKN025 TEMPO 0003 1/2SM SHSN BKN008 BKN012 TEMPO 0003 1/2SM SHSN BKN008 BKN012 FM0300 32009KT P6SM VCSH SCT015 BKN035 FM0300 32009KT P6SM VCSH SCT015 BKN035 TEMPO 0307 2SM -SHSN BKN015 TEMPO 0307 2SM -SHSN BKN015 FM1000 32008KT P6SM VCSH SCT020 BKN040 FM1000 32008KT P6SM VCSH SCT020 BKN040 FM1400 32010KT P6SM SCT020 SCT050 FM1400 32010KT P6SM SCT020 SCT050 FM1900 33014G22KT P6SM BKN045FM1900 33014G22KT P6SM BKN045

What do you think of the TAF compared to the radar?What do you think of the TAF compared to the radar?

• Why 2SM –SHSN for 3 hours in the main body of the first line?Why 2SM –SHSN for 3 hours in the main body of the first line?• Why TEMPO 1/2SM SHSN for 3 hours? Why TEMPO 1/2SM SHSN for 3 hours?

Now it’s an hour later…let’s see what the radar looked like…Now it’s an hour later…let’s see what the radar looked like…

• Here’s what the METAR at 2355Z looked like:Here’s what the METAR at 2355Z looked like:• KRNO KRNO 102355Z102355Z AUTO 00000KT AUTO 00000KT 10SM SCT05010SM SCT050 BKN065 OVC090 02/M02 A2995 BKN065 OVC090 02/M02 A2995

RMK AO2 SNB08E36 SLP144 MTN TOPS OBSCD ALQDS P0002 60010RMK AO2 SNB08E36 SLP144 MTN TOPS OBSCD ALQDS P0002 60010

• What would you do next, if anything?What would you do next, if anything?

• If you chose to amend, what would you have changed? Let’s look at the 00Z If you chose to amend, what would you have changed? Let’s look at the 00Z TAF again…TAF again…

• KRNO KRNO 102320Z 110024102320Z 110024 01010KT 2SM -SHSN BKN012 BKN025 01010KT 2SM -SHSN BKN012 BKN025 TEMPO 0003 1/2SM SHSN BKN008 BKN012 TEMPO 0003 1/2SM SHSN BKN008 BKN012 FM0300 32009KT P6SM VCSH SCT015 BKN035 FM0300 32009KT P6SM VCSH SCT015 BKN035 TEMPO 0307 2SM -SHSN BKN015 TEMPO 0307 2SM -SHSN BKN015 FM1000 32008KT P6SM VCSH SCT020 BKN040 FM1000 32008KT P6SM VCSH SCT020 BKN040 FM1400 32010KT P6SM SCT020 SCT050 FM1400 32010KT P6SM SCT020 SCT050 FM1900 33014G22KT P6SM BKN045FM1900 33014G22KT P6SM BKN045

• Here’s an amendment that went out 40 minutes later…Here’s an amendment that went out 40 minutes later…

• KRNO KRNO AMD 110004Z 110024AMD 110004Z 110024 01008KT P6SM VCSH SCT015 SCT050 BKN070 01008KT P6SM VCSH SCT015 SCT050 BKN070 TEMPO 0103 1/2SM SHSN BKN008 BKN012 TEMPO 0103 1/2SM SHSN BKN008 BKN012 FM0300 32009KT P6SM VCSH SCT015 BKN035 FM0300 32009KT P6SM VCSH SCT015 BKN035 TEMPO 0307 2SM -SHSN BKN015 TEMPO 0307 2SM -SHSN BKN015 FM1000 32008KT P6SM VCSH SCT020 BKN040 FM1000 32008KT P6SM VCSH SCT020 BKN040 FM1400 32010KT P6SM SCT020 SCT050 FM1400 32010KT P6SM SCT020 SCT050 FM1900 33014G22KT P6SM BKN045FM1900 33014G22KT P6SM BKN045

Let’s look at the METARS from 00Z until 06Z…Let’s look at the METARS from 00Z until 06Z…

• KRNO KRNO 102355Z102355Z AUTO 00000KT AUTO 00000KT 10SM SCT05010SM SCT050 BKN065 OVC090 02/M02 A2995 BKN065 OVC090 02/M02 A2995 RMK AO2 SNB08E36 SLP144 MTN TOPS OBSCD ALQDS P0002 60010RMK AO2 SNB08E36 SLP144 MTN TOPS OBSCD ALQDS P0002 60010

• KRNO KRNO 110055Z110055Z 00000KT 00000KT 10SM SCT05010SM SCT050 BKN075 03/M03 A2993 RMK AO2 BKN075 03/M03 A2993 RMK AO2 SLP140 MTN TOPS OBSCD DSNT SW T00281028=SLP140 MTN TOPS OBSCD DSNT SW T00281028=

• KRNO KRNO 110155Z110155Z 04005KT 04005KT 7SM -SN BKN0417SM -SN BKN041 BKN065 02/M03 A2994 RMK AO2 BKN065 02/M03 A2994 RMK AO2 RAB38E39SNB39 SLP145 MTN TOPS OBSCD DSNT SW E P0000=RAB38E39SNB39 SLP145 MTN TOPS OBSCD DSNT SW E P0000=

• KRNO KRNO 110255Z110255Z 00000KT 00000KT 10SM BKN07010SM BKN070 BKN085 02/M03 A2994 RMK AO2 BKN085 02/M03 A2994 RMK AO2 SNE0158 SLP147 P0000 60000 T00171033 55000=SNE0158 SLP147 P0000 60000 T00171033 55000=

• KRNO KRNO 110355Z110355Z 32007KT 32007KT 10SM BKN05510SM BKN055 BKN070 03/M06 A2995 RMK AO2 BKN070 03/M06 A2995 RMK AO2 SLP145 T00281061=SLP145 T00281061=

• KRNO KRNO 110455Z110455Z 36015G18KT 36015G18KT 10SM SCT04710SM SCT047 BKN060 BKN090 03/M05 A2994 BKN060 BKN090 03/M05 A2994 RMK AO2 PK WND 32026/0428 SNB31E42 SLP140 P0000 T00281050=RMK AO2 PK WND 32026/0428 SNB31E42 SLP140 P0000 T00281050=

• KRNO KRNO 110531Z110531Z 36009KT 36009KT 8SM -SN BKN0278SM -SN BKN027 OVC042 02/M04 A2995 RMK AO2 OVC042 02/M04 A2995 RMK AO2 SNB28 P0000=SNB28 P0000=

• KRNO KRNO 110555Z110555Z 11006KT 11006KT 10SM FEW027 OVC04010SM FEW027 OVC040 01/M03 A2994 RMK AO2 01/M03 A2994 RMK AO2 SNB28E47 SLP145 P0000 60000 T00061028 10033 20006 56001=SNB28E47 SLP145 P0000 60000 T00061028 10033 20006 56001=

• Good amendment or bad?Good amendment or bad?

• Would you have amended before 06Z?Would you have amended before 06Z?

• No amendment was issued… 06Z TAF went out…No amendment was issued… 06Z TAF went out…

How did we verify???How did we verify???

POD/FAR For RNO TAFPOD/FAR For RNO TAF

• Scheduled TAFs ONLYScheduled TAFs ONLY - Ceilings < 1000 feet, Visibility < - Ceilings < 1000 feet, Visibility < 3SM3SM– POD – 0.00POD – 0.00– FAR – 1.00FAR – 1.00

• Scheduled and Amended TAFsScheduled and Amended TAFs – Cigs < 1000 feet, Vis < – Cigs < 1000 feet, Vis < 3SM3SM– POD – 0.35POD – 0.35– FAR – 0.84FAR – 0.84

AMENDMENTS IMPROVED OUR SCORES!!AMENDMENTS IMPROVED OUR SCORES!!

POD/FAR For RNO TAFPOD/FAR For RNO TAF

• Scheduled TAFs ONLYScheduled TAFs ONLY - Ceilings < 3000 feet, Visibility < - Ceilings < 3000 feet, Visibility < 5SM5SM– POD – 0.80POD – 0.80– FAR – 0.68FAR – 0.68

• Scheduled and Amended TAFsScheduled and Amended TAFs – Cigs < 3000 feet, Vis < – Cigs < 3000 feet, Vis < 5SM5SM– POD – 0.70POD – 0.70– FAR – 0.67FAR – 0.67

AMENDMENTS DID NOT IMPROVE OUR AMENDMENTS DID NOT IMPROVE OUR SCORES!!SCORES!!