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Criteria for the Issuance of Weather Warnings

User’s Guide | Criteria for the Warnings

 

Criteria for Portugal Mainland

Warning Parameter Yellow Orange Red Units Notes
Wind Maximum Gust 70 to 90 91 to 130 > 130 km/h  
90 to 110 111 to 130 > 130 km/h In the highlands
Rainfall Rain/Showers 10 to 20 21 to 40 > 40 mm/1h Milimeters in 1 hour
30 to 40 41 to 60 > 60 mm/6h Milimeters in 6 hour
Snow Snowfall 1 a 5 6 a 15 > 15 cm Quota below 1000 m
1 a 10 11 a 30 > 30 cm Quota between 1000 and 1600 m
1 a 25 26 a 50 > 50 cm Quota above 1600 m
Thunderstorm Electric Discharges a) b) c)   a) Frequent and scattered.
b) Frequent and close together.
c) Very frequent and excessively close together.
Fog Visibility  *≥ 48h  *≥ 72h  *≥ 96h   * - duration
High Temperature Maximum Temperature # to # * # to # * > # * ºC * - duration ≥ 48 horas
Low Temperature Minimum Temperature # to # * # to # * < # * ºC * - duration ≥ 48 horas
Coastal Event Significant Wave Height 4 to 5 5 to 7 > 7 m  
2 to 3 3 to 5 > 5 m With swell from Southwest off the southern Algarve coast

# - Values for each Region in the next table.

 

District Minimum Temperature Maximum Temperature
Yellow Orange Red Yellow Orange Red
Viana do Castelo -1 to -3 -4 to -5 < -5 32 to 36 37 to 38 > 38
Braga -1 to -3 -4 to -5 < -5 34 to 36 37 to 38 > 38
Porto  1 to -1 -2 to -3 < -3 32 to 36 37 to 38 > 38
Vila Real -2 to -3 -4 to -5 < -5 34 to 37 38 to 39 > 39
Bragança -4 to -7 -8 to -10 < -10 34 to 36 37 to 38 > 38
Viseu -2 to -4 -5 to -7 < -7 35 to 38 39 to 40 > 40
Guarda -3 to -6 -7 to -10 < -10 31 to 33 34 to 36 > 36
Castelo Branco 0 to -2 -3 to -4 < -4 37 to 39 40 to 41 > 41
Aveiro 3 to 1 0 to -1 < -1 31 to 35 36 to 38 > 38
Coimbra -1 to -3 -4 to -5 < -5 35 to 38 39 to 40 > 40
Leiria -1 to -3 -4 to -6 < -6 31 to 35 36 to 40 > 40
Lisboa 3 to 1 0 to -1 < -1 34 to 37 38 to 40 > 40
Setúbal 1 to -2 -3 to -4 < -4 35 to 39 40 to 42 > 42
Santarém 1 to -1 -2 to -3 < -3 38 to 41 42 to 43 > 43
Portalegre 1 to -1 -2 to -5 < -5 36 to 39 40 to 41 > 41
Évora 1 to -1 -2 to -4 < -4 37 to 40 41 to 43 > 43
Beja 1 a -1 -2 to -4 < -4 37 to 40 41 to 43 > 43
Faro 4 to 1 0 to -1 < -1 33 to 37 38 to 41 > 41

 

Criteria for Madeira Archipelago

Warning Parameter Yellow Orange Red Units Notes
Wind Maximum Gust 70 to 90 91 to 130 > 130 km/h  
90 to 110 111 to 130 > 130 km/h In the highlands
Rainfall Rain/Showers 10 to 20 21 to 40 > 40 mm/1h Milimeters in 1 hour
30 to 40 41 to 60 > 60 mm/6h Milimeters in 6 hour
Snow Snowfall 1 a 5 6 a 15 > 15 cm Quota below 1000 m
1 a 10 11 a 30 > 30 cm Quota between 1000 and 1600 m
1 a 25 26 a 50 > 50 cm Quota above 1600 m
Thunderstorm Electric Discharges a) b) c)   a) Frequent and scattered.
b) Frequent and close together.
c) Very frequent and excessively close together.
Fog Visibility  *≥ 48h  *≥ 72h  *≥ 96h   * - duration
High Temperature Maximum Temperature # to # * # to # * > # * ºC * - duration ≥ 48 horas
Low Temperature Minimum Temperature # to # * # to # * < # * ºC * - duration ≥ 48 horas
Coastal Event Significant Wave Height 4 to 5 5 to 7 > 7 m  

# - Values for each region in the following table.

 

Region Minimum Temperature Maximum Temperature
Yellow Orange Red Yellow Orange Red
Costa Norte 7 a 8 5 a 6 < 5 24 a 26 27 a 30 > 30
Regiões Montanhosas -2 a -1 -4 a -2 < -4 25 a 27 28 a 29 > 29
Costa Sul 10 a 11 8 a 9 < 8 27 a 29 30 a 35 > 35
Porto Santo 10 a 11 8 a 9 < 8 26 a 27 28 a 31 > 31

 

Criteria for Azores Archipelago

Warning Parameter Yellow Orange Red Units Notes
Wind Mean Wind Speed 65 - 74 75 - 87 > 87 km/h  
Maximum Gust 85 to 100 101 to 130 > 130 km/h  
Rainfall Rain/Showers 10 to 20 21 to 40 > 40 mm/1h Millimeters in 1 hour
25 to 40 41 to 60 > 60 mm/6h Millimeters in 6 hour
Snow Snowfall 1 a 5 6 a 15 > 15 cm Quota below 1000 m
1 a 10 11 a 30 > 30 cm Quota between 1000 and 1600 m
1 a 25 26 a 50 > 50 cm Quota above 1600 m
Thunderstorm Electric Discharges a) b) c)   a) Frequent and scattered.
b) Frequent and close together.
c) Very frequent and excessively close together.
Fog Visibility  *≥ 48h  *≥ 72h  *≥ 96h   * - duration
High Temperature Maximum Temperature # to # * # to # * > # * ºC * - duration ≥ 48 horas
Low Temperature Minimum Temperature # to # * # to # * < # * ºC * - duration ≥ 48 horas
Coastal Event Significant Wave Height 6 to 7 7 to 9 > 9 m  

# - Values for each Group in the next table.

 

Group Minimum Temperature Maximum Temperature
Yellow Orange Red Yellow Orange Red
Oriental 8 to 5 4 to 0 < 0 28 to 29 30 to 31 > 31
Central 8 to 5 4 to 0 < 0 28 to 29 30 to 31 > 31
Occidental  8 to 5 4 to 0 < 0 28 to 29 30 to 31 > 31

 

Likely impacts per warning

Warning Yellow Orange Red
SnowSnow Disturbance caused by snowfall and icing (eg, conditioned or restricted roads, damage to structures or trees due to snow accumulation, impaired local supplies). Moderate disturbance caused by snowfall and ice formation (eg, conditioned or restricted roads, damage to structures or trees due to snow accumulation, impaired local supplies). Severe disturbance caused by snowfall and icing (eg restricted roads, damage to structures or trees due to snow accumulation, impaired local supplies).