Region Lower 48
The readings under the map are for the whole map, not only the part shown.
ECMWF · Run 06Z 1 Oct · +0 h · Valid Thu 06Z 1 Oct
Deepest column 75 mm at 20.0N 109.25W
Deepest column 75 mm, 295 km S of Cabo San Lucas, Mexico
Deepest column 74 mm at 20.0N 110.25W
Deepest column 83 mm at 20.0N 110.0W
Deepest column 74 mm at 20.0N 111.5W
Deepest column 74 mm at 20.0N 111.25W
Deepest column 74 mm at 20.0N 110.75W
Deepest column 73 mm at 20.0N 112.75W
Deepest column 76 mm at 20.0N 112.5W
Deepest column 82 mm at 20.0N 113.0W
Deepest column 81 mm at 20.0N 113.75W
Deepest column 82 mm at 20.0N 114.25W
Deepest column 84 mm at 20.0N 114.5W
Deepest column 83 mm at 20.0N 115.0W
Deepest column 84 mm at 20.0N 116.25W
Deepest column 85 mm at 20.0N 117.0W
Deepest column 83 mm at 20.0N 117.5W
Deepest column 77 mm at 20.0N 118.5W
Deepest column 73 mm at 20.0N 119.0W
Deepest column 78 mm at 20.0N 119.75W
Deepest column 75 mm at 20.0N 120.5W
One ECMWF run, issued 06Z 1 Oct — played forward 6 hours at a time, from the analysis to 120 hours out.
Methodology
PWAT — precipitable water — is how much water vapour the air overhead holds, as the depth of water it would make if it all fell at once.
Six-hourly to 120 hours. ECMWF's 06Z run forecasts out to 144 hours; this film stops at 120.
The colours are a depth scale, the same everywhere: the cream band is a depth, not a normal. The same column is deep for Salt Lake City and shallow for Miami, so this map cannot say whether the air is unusual — the Relative to normal chart ranks each place against its own record, and that is the one to read for that.
GFS files this field as PWAT and ECMWF as total column water vapour, the same quantity. Uncorrected model output.
This map is drawn from model output we store ourselves, not from anyone's picture of it, and is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). The per-city read of the same day — which cities the models are fighting about, and what the discussion makes of it — is on the national page.
Sources and licences
- ECMWF: IFS, from ECMWF's open data. This service is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). Source: www.ecmwf.int. This ECMWF data is published under a Creative Commons Attribution 4.0 International (CC BY 4.0). ECMWF does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use.
What we change: each field is cropped to the frame these maps share when we download it, and each map then smooths, contours, differences or ranks those numbers as its Methodology says. These are our maps of the providers' numbers, not their products, and none of them has reviewed or endorsed this site.
Coastlines, borders, lakes and place names: Natural Earth, public domain.