Merry Christmas from the GEFS computer model. 🎄
November 25, 2024 at 6:34 PM
Merry Christmas from the GEFS computer model. 🎄
Merry Christmas from the GEFS model! 🎅
December 8, 2024 at 4:10 AM
Merry Christmas from the GEFS model! 🎅
The direction of travel is clear in 12z GEFS going forward to end of 2025 progressively colder....
December 18, 2025 at 5:57 PM
The direction of travel is clear in 12z GEFS going forward to end of 2025 progressively colder....
IMPORTANT NOTE 🚨
When looking at ensemble means, beware of the "survivors bias". For example, the GEFS *mean* misses the coast... but most GEFS members make landfall!
This has to do with the storm timing. Consider how some members move the storm faster than others... (cont.)
When looking at ensemble means, beware of the "survivors bias". For example, the GEFS *mean* misses the coast... but most GEFS members make landfall!
This has to do with the storm timing. Consider how some members move the storm faster than others... (cont.)
September 26, 2025 at 2:12 AM
IMPORTANT NOTE 🚨
When looking at ensemble means, beware of the "survivors bias". For example, the GEFS *mean* misses the coast... but most GEFS members make landfall!
This has to do with the storm timing. Consider how some members move the storm faster than others... (cont.)
When looking at ensemble means, beware of the "survivors bias". For example, the GEFS *mean* misses the coast... but most GEFS members make landfall!
This has to do with the storm timing. Consider how some members move the storm faster than others... (cont.)
Next 10-day forecast 2m temp anomaly on GEFS. Continental cold gathering in potency post Xmas.
Get your winter coats ready! 🥶 European heating demand will be skyrocketing.
Get your winter coats ready! 🥶 European heating demand will be skyrocketing.
December 19, 2025 at 5:49 PM
Next 10-day forecast 2m temp anomaly on GEFS. Continental cold gathering in potency post Xmas.
Get your winter coats ready! 🥶 European heating demand will be skyrocketing.
Get your winter coats ready! 🥶 European heating demand will be skyrocketing.
Just added "chiclet plots" to my website, showing the North American weather regime of the ensemble mean for the past 90 runs of the subseasonal NCEP GEFS & ECMWF IFS
GEFS: simonleewx.com/gefs_north_a...
IFS: simonleewx.com/ecmwf_north_...
GEFS: simonleewx.com/gefs_north_a...
IFS: simonleewx.com/ecmwf_north_...
November 21, 2025 at 4:14 PM
Just added "chiclet plots" to my website, showing the North American weather regime of the ensemble mean for the past 90 runs of the subseasonal NCEP GEFS & ECMWF IFS
GEFS: simonleewx.com/gefs_north_a...
IFS: simonleewx.com/ecmwf_north_...
GEFS: simonleewx.com/gefs_north_a...
IFS: simonleewx.com/ecmwf_north_...
Informative thank u GEFS
August 29, 2025 at 3:52 PM
Informative thank u GEFS
GEFS: New England trough on Sunday
GFS: New England ridge on Sunday
This might be one of the most significant large-scale GFS vs GEFS differences I've seen in a long time
GFS: New England ridge on Sunday
This might be one of the most significant large-scale GFS vs GEFS differences I've seen in a long time
April 15, 2025 at 10:24 PM
GEFS: New England trough on Sunday
GFS: New England ridge on Sunday
This might be one of the most significant large-scale GFS vs GEFS differences I've seen in a long time
GFS: New England ridge on Sunday
This might be one of the most significant large-scale GFS vs GEFS differences I've seen in a long time
Someone turn the GEFS ensembles off.
March 8, 2025 at 5:30 PM
Someone turn the GEFS ensembles off.
The Arctic stratospheric polar vortex, up at 10hPa (~30km), looks like to approach date-record strength in early December. Both ECMWF and GEFS forecasts continue to show this.
🧵
🧵
November 24, 2024 at 2:53 PM
The Arctic stratospheric polar vortex, up at 10hPa (~30km), looks like to approach date-record strength in early December. Both ECMWF and GEFS forecasts continue to show this.
🧵
🧵
GREAT NEWS! 🎉 The GEFS Plumes website is working again after an extended outage! I'll try to backfill some recent forecasts before AMS as well. 🌎
www.emc.ncep.noaa.gov/users/meg/ge...
www.emc.ncep.noaa.gov/users/meg/ge...
EMC GEFS plumes
www.emc.ncep.noaa.gov
January 10, 2025 at 3:51 PM
GREAT NEWS! 🎉 The GEFS Plumes website is working again after an extended outage! I'll try to backfill some recent forecasts before AMS as well. 🌎
www.emc.ncep.noaa.gov/users/meg/ge...
www.emc.ncep.noaa.gov/users/meg/ge...
According to the GEFS hour 840 plot, which has never been wrong, the winter solstice will be warmer than normal just about everywhere.
November 17, 2024 at 3:26 AM
According to the GEFS hour 840 plot, which has never been wrong, the winter solstice will be warmer than normal just about everywhere.
Likely turning colder later next week. Interesting in 06z GEFS about one third bring significantly cold conditions to London daytime highs below freezing.
Unusual to see that with this lead time, something I’ve not seen in a while….
Unusual to see that with this lead time, something I’ve not seen in a while….
January 16, 2026 at 4:01 PM
Likely turning colder later next week. Interesting in 06z GEFS about one third bring significantly cold conditions to London daytime highs below freezing.
Unusual to see that with this lead time, something I’ve not seen in a while….
Unusual to see that with this lead time, something I’ve not seen in a while….
gef it's your birthday
happy birthday gef
happy birthday gef
April 24, 2025 at 12:22 PM
gef it's your birthday
happy birthday gef
happy birthday gef
EMC GEFS Plumes hits were up 300% today! It's almost like there's a storm coming or something... 😉 Thanks, all!
www.emc.ncep.noaa.gov/users/meg/ge...
www.emc.ncep.noaa.gov/users/meg/ge...
EMC GEFS plumes
www.emc.ncep.noaa.gov
January 22, 2026 at 2:47 AM
EMC GEFS Plumes hits were up 300% today! It's almost like there's a storm coming or something... 😉 Thanks, all!
www.emc.ncep.noaa.gov/users/meg/ge...
www.emc.ncep.noaa.gov/users/meg/ge...
Oh, here we go again…
UK record max 40.3°C, 19 July 2022.
Max possible in current climate is just above 45°C (Kay et al. 2025 doi.org/10.1002/wea....)
GEFS shows non-zero chance of 43°C in 2 weeks (caveat: GEFS land model sometimes overdries —> overheats)
UK record max 40.3°C, 19 July 2022.
Max possible in current climate is just above 45°C (Kay et al. 2025 doi.org/10.1002/wea....)
GEFS shows non-zero chance of 43°C in 2 weeks (caveat: GEFS land model sometimes overdries —> overheats)
June 18, 2025 at 10:06 AM
Oh, here we go again…
UK record max 40.3°C, 19 July 2022.
Max possible in current climate is just above 45°C (Kay et al. 2025 doi.org/10.1002/wea....)
GEFS shows non-zero chance of 43°C in 2 weeks (caveat: GEFS land model sometimes overdries —> overheats)
UK record max 40.3°C, 19 July 2022.
Max possible in current climate is just above 45°C (Kay et al. 2025 doi.org/10.1002/wea....)
GEFS shows non-zero chance of 43°C in 2 weeks (caveat: GEFS land model sometimes overdries —> overheats)
North American weather regime forecast pages on my website now redesigned & updated!
GEFS: simonleewx.com/gefs_north_a...
ECMWF: simonleewx.com/ecmwf_north_...
GEFS: simonleewx.com/gefs_north_a...
ECMWF: simonleewx.com/ecmwf_north_...
November 14, 2024 at 11:56 AM
North American weather regime forecast pages on my website now redesigned & updated!
GEFS: simonleewx.com/gefs_north_a...
ECMWF: simonleewx.com/ecmwf_north_...
GEFS: simonleewx.com/gefs_north_a...
ECMWF: simonleewx.com/ecmwf_north_...
The 12Z GEFS is more insane than yesterday. OUTBREAK!
March 9, 2025 at 5:08 PM
The 12Z GEFS is more insane than yesterday. OUTBREAK!
GEFS is basically going for the Pacific Trough regime for the full subseasonal run. El Niño's North Pacific teleconnection activated and locked? simonleewx.com/gefs_north_a...
September 22, 2026 at 11:21 AM
GEFS is basically going for the Pacific Trough regime for the full subseasonal run. El Niño's North Pacific teleconnection activated and locked? simonleewx.com/gefs_north_a...
The GEFS really does like to throw out some extreme temperatures these days..
July 12, 2025 at 11:48 AM
The GEFS really does like to throw out some extreme temperatures these days..
Mapas mostram as temperaturas máximas previstas pelo modelo GEFS (versão ensemble do GFS) entre terça e sexta-feira.
February 9, 2026 at 10:06 PM
Mapas mostram as temperaturas máximas previstas pelo modelo GEFS (versão ensemble do GFS) entre terça e sexta-feira.
Technically speaking, ~1% of the time-lagged extended GEFS members show a snow event near New Orleans during AMS
December 27, 2024 at 4:08 PM
Technically speaking, ~1% of the time-lagged extended GEFS members show a snow event near New Orleans during AMS
lass des gefs kads orrrrr
September 4, 2023 at 2:40 PM
lass des gefs kads orrrrr
The woke GEFS has learned its lesson.
By Chris Chartz Martz and Susan Collins
By Chris Chartz Martz and Susan Collins
Merry Torchmas to the vast majority. #ClimateChange #Cooked
December 11, 2024 at 4:43 AM
The woke GEFS has learned its lesson.
By Chris Chartz Martz and Susan Collins
By Chris Chartz Martz and Susan Collins
kühl deng kni gefs!
July 24, 2025 at 9:07 AM
kühl deng kni gefs!