Weather Forecast Near the Ground

As an aid to planning astronomical observing sessions, we offer wind, temperature, and relative humidity forecasts. Wind and temperature forecasts are useful for deciding what clothing to wear, and windy conditions can impair observing due to telescope vibrations. The relative humidity forecast can help astronomers decide whether or not to apply gentle heat to lenses to prevent dew formation. Note that the actual 10km resolution RDPS model used to produce these forecasts has cold bias and weak wind bias on top of mountains.

Winds forecast are represented by 6 colour levels.

Dark blue: Calm winds.
Medium blue: Light winds.
Light blue: Light to moderate winds.
Pale blue: Moderate winds.
Grey: Strong winds.
White: Very strong winds.

Regional model, surface wind forecast for North America

Surface wind forecast Temperature forecast Relative humidity forecast
00 UTC 12 UTC 00 UTC 12 UTC 00 UTC 12 UTC
T+03 T+03 T+03 T+03 T+03 T+03
T+04 T+04 T+04 T+04 T+04 T+04
T+05 T+05 T+05 T+05 T+05 T+05
T+06 T+06 T+06 T+06 T+06 T+06
T+07 T+07 T+07 T+07 T+07 T+07
T+08 T+08 T+08 T+08 T+08 T+08
T+09 T+09 T+09 T+09 T+09 T+09
T+10 T+10 T+10 T+10 T+10 T+10
T+11 T+11 T+11 T+11 T+11 T+11
T+12 T+12 T+12 T+12 T+12 T+12
T+13 T+13 T+13 T+13 T+13 T+13
T+14 T+14 T+14 T+14 T+14 T+14
T+15 T+15 T+15 T+15 T+15 T+15
T+16 T+16 T+16 T+16 T+16 T+16
T+17 T+17 T+17 T+17 T+17 T+17
T+18 T+18 T+18 T+18 T+18 T+18
T+19 T+19 T+19 T+19 T+19 T+19
T+20 T+20 T+20 T+20 T+20 T+20
T+21 T+21 T+21 T+21 T+21 T+21
T+22 T+22 T+22 T+22 T+22 T+22
T+23 T+23 T+23 T+23 T+23 T+23
T+24 T+24 T+24 T+24 T+24 T+24
T+25 T+25 T+25 T+25 T+25 T+25
T+26 T+26 T+26 T+26 T+26 T+26
T+27 T+27 T+27 T+27 T+27 T+27
T+28 T+28 T+28 T+28 T+28 T+28
T+29 T+29 T+29 T+29 T+29 T+29
T+30 T+30 T+30 T+30 T+30 T+30
T+31 T+31 T+31 T+31 T+31 T+31
T+32 T+32 T+32 T+32 T+32 T+32
T+33 T+33 T+33 T+33 T+33 T+33
T+34 T+34 T+34 T+34 T+34 T+34
T+35 T+35 T+35 T+35 T+35 T+35
T+36 T+36 T+36 T+36 T+36 T+36
T+37 T+37 T+37 T+37 T+37 T+37
T+38 T+38 T+38 T+38 T+38 T+38
T+39 T+39 T+39 T+39 T+39 T+39
T+40 T+40 T+40 T+40 T+40 T+40
T+41 T+41 T+41 T+41 T+41 T+41
T+42 T+42 T+42 T+42 T+42 T+42
T+43 T+43 T+43 T+43 T+43 T+43
T+44 T+44 T+44 T+44 T+44 T+44
T+45 T+45 T+45 T+45 T+45 T+45
T+46 T+46 T+46 T+46 T+46 T+46
T+47 T+47 T+47 T+47 T+47 T+47
T+48 T+48 T+48 T+48 T+48 T+48
Animation Animation Animation Animation Animation Animation

T+hh refers to the forecast’s time interval (hh), in hours, from the hour T of the model’s initial run time. The hour T is indicated, in Universal Time, at the top of each column.