IsobarMeteorologisk / Bergen

Meteorological service / the west coast / since 1867

988hPa

Falling. A deep low crossing on Saturday, sixty-two stations watching it, and a forecast that will tell you how sure it is.

Seven days

Today

11°

6° overnight

Rain, heavy at times

1002 hPa

90 % confidence

Tue

9°

5° overnight

Squally showers

996 hPa

85 % confidence

Wed

8°

3° overnight

Bright, cold, dry

1008 hPa

70 % confidence

Thu

10°

4° overnight

Cloud thickening

1004 hPa

60 % confidence

Fri

12°

7° overnight

Rain arriving west

994 hPa

55 % confidence

Sat

13°

8° overnight

Wet and windy

988 hPa

45 % confidence

Sun

11°

7° overnight

Showers, easing

997 hPa

35 % confidence

The useful part of a forecast is not the number. It is how far the fifty runs of the model disagreed with each other, and we have published that on the front page since 1994.

Isobar is the regional meteorological service for the western seaboard. It keeps sixty-two stations, eleven of them still read by hand at six in the morning, and an archive going back to 1867.

Everything the service produces is free to use, including the observations, the model output and the mistakes, which are catalogued in the same archive as everything else.

How a forecast is made

Three steps, and the third is the one that took a reorganisation to get right.

01

Observe first

Sixty-two automatic stations reporting every ten minutes, plus eleven where a person still walks out at 06:00 and reads a thermometer, because the model needs something it did not invent.

02

Run it fifty times

The forecast is an ensemble: the same model from fifty slightly different starting points. What we publish is where those fifty agree and, more usefully, where they do not.

03

Say how sure

Every forecast carries a confidence. A confident wrong forecast costs more than an uncertain one, and pretending to certainty is the failure this service was reorganised to stop in 1994.

In force this week

Colour is severity. The percentage is how likely the event is, not how bad it will be.

  1. YellowWindCoast, Sogn to StadFri 18:00 – Sat 09:0070 %
  2. OrangeRainInner HordalandFri 22:00 – Sun 06:0055 %
  3. YellowRainBergen and environsSat 03:00 – Sat 21:0080 %
  4. YellowWavesOuter coastSat 00:00 – Sat 18:0065 %
  5. GreenSnowAbove 900 mSun 12:00 – Mon 06:0030 %

The 1991–2020 normal

Mean temperature by month at the city station, in degrees. The tint is the number.

1.9Jan
1.8Feb
3.7Mar
6.2Apr
10.4May
13.2Jun
15.1Jul
14.8Aug
12.0Sep
8.9Oct
5.1Nov
2.6Dec
33.4 °C
Highest, Ullensvang, 1947
−26.1 °C
Lowest, Sognefjell, 1987
229 mm
Wettest day, Modalen, 2005
62.4 m/s
Strongest gust, Kråkenes, 1992

A forecast that is right and was lucky is worth less than one that was wrong and said so.

Ingrid Hovden, chief forecaster

Sixty-two stations

Fourteen of the long-running ones. Every reading any of them has ever made is downloadable.

  1. SN50540Bergen – Florida12 m1904–Manned 06:00
  2. SN50500Bergen – Sandsli48 m1979–Automatic
  3. SN51530Voss – Bø125 m1891–Manned 06:00
  4. SN52535Modalen114 m1955–Automatic
  5. SN53101Vangsnes49 m1876–Manned 06:00
  6. SN54110Fedje39 m1949–Automatic
  7. SN55290Kvamskogen455 m1968–Automatic
  8. SN56420Ullensvang12 m1867–Manned 06:00
  9. SN57420Slåtterøy fyr32 m1922–Automatic
  10. SN58900Sauda18 m1895–Automatic
  11. SN59800Stad – Kråkenes40 m1997–Automatic
  12. SN60990Takle38 m1969–Automatic
  13. SN61770Sognefjell1 413 m1978–Automatic
  14. SN62480Bulken324 m1895–Manned 06:00

What we publish

Free
Every observation and every forecast, as an API and as a file.
Marine
A separate coastal product, issued four times a day, in Norwegian and English.
Aviation
TAF and METAR for six aerodromes, on the international schedule.
Archive
Daily observations back to 1867, digitised from the ledgers by hand.

Observations, data, corrections

Four stations on the watch

  • Bergen

    Forecast desk, staffed always

    Allégaten 70, 5007

    60.39 N 5.32 E

  • Ålesund

    Coastal radar

    Nedre Strandgate 8, 6002

    62.47 N 6.15 E

  • Tromsø

    Northern synoptic

    Kirkegata 2, 9008

    69.65 N 18.96 E

  • Bjørnøya

    Automatic, visited twice a year

    Herwighamna

    74.50 N 19.00 E

The forecast desk is staffed at all hours; everybody else answers between eight and four, and the archive answers when it can.