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Criteria for the Issuance of Weather Warnings
User guide | Issuing criteria
Criteria for Mainland Portugal
| Warning | Parameter | Yellow | Orange | Red | Unit | Notes |
|---|---|---|---|---|---|---|
| Wind | Maximum Wind Gust | 70 to 90 | 91 to 130 | > 130 | km/h | |
| 90 to 110 | 111 to 130 | > 130 | km/h | In highland areas | ||
| Precipitation | Rain/Showers | 10 to 20 | 21 to 40 | > 40 | mm/1h | Millimetres in one hour |
| 30 to 40 | 41 to 60 | > 60 | mm/6h | Millimetres in 6 hours | ||
| Snow | Snowfall with accumulation | 1 to 5 | 6 to 15 | > 15 | cm | Altitude below 1000 m |
| 1 to 10 | 11 to 30 | > 30 | cm | Altitude from 1000 to 1600 m | ||
| 5 to 25 | 26 to 50 | > 50 | cm | Altitude above 1600 m | ||
| Thunderstorm | Electrical discharges; Showers; Hail; Maximum Wind Gust. |
a) | b) | c) | Expected phenomena by warning level | |
| Fog | Visibility | *≥ 48h | *≥ 72h | *≥ 96h | * - duration | |
| Hot Weather | Maximum Temperature | # to # * | # to # * | > # * | ºC | * - duration ≥ 48 hours |
| Cold Weather | Minimum Temperature | # to # * | # to # * | < # * | ºC | * - duration ≥ 48 hours |
| Rough Sea | Significant Wave Height | 4 to 5 | 5 to 7 | > 7 | m | |
| 2 to 3 | 3 to 5 | > 5 | m | With southeast swell on the southern coast of the Algarve |
# - Values for each District shown in the following 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 to -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 the Madeira Archipelago
| Warning | Parameter | Yellow | Orange | Red | Unit | Notes |
|---|---|---|---|---|---|---|
| Wind | Maximum Wind Gust | 70 to 90 | 91 to 130 | > 130 | km/h | |
| 90 to 110 | 111 to 130 | > 130 | km/h | In highland areas | ||
| Precipitation | Rain/Showers | 10 to 20 | 21 to 40 | > 40 | mm/1h | Millimetres in one hour |
| 30 to 40 | 41 to 60 | > 60 | mm/6h | Millimetres in 6 hours | ||
| Snow | Snowfall with accumulation | 1 to 5 | 6 to 15 | > 15 | cm | Altitude below 1000 m |
| 1 to 10 | 11 to 30 | > 30 | cm | Altitude from 1000 to 1600 m | ||
| 5 to 25 | 26 to 50 | > 50 | cm | Altitude above 1600 m | ||
| Thunderstorm | Electrical discharges; Showers; Hail; Maximum Wind Gust. |
a) | b) | c) | Expected phenomena by warning level | |
| Fog | Visibility | *≥ 48h | *≥ 72h | *≥ 96h | * - duration | |
| Hot Weather | Maximum Temperature | # to # * | # to # * | > # * | ºC | * - duration ≥ 48 hours |
| Cold Weather | Minimum Temperature | # to # * | # to # * | < # * | ºC | * - duration ≥ 48 hours |
| Rough Sea | Significant Wave Height | 4 to 5 | 5 to 7 | > 7 | m |
# - Values for each region shown in the following table.
| Region | Minimum Temperature | Maximum Temperature | ||||
|---|---|---|---|---|---|---|
| Yellow | Orange | Red | Yellow | Orange | Red | |
| North Coast | 7 to 8 | 5 to 6 | < 5 | 24 to 26 | 27 to 30 | > 30 |
| Mountainous Regions | -2 to -1 | -4 to -2 | < -4 | 25 to 27 | 28 to 29 | > 29 |
| South Coast | 10 to 11 | 8 to 9 | < 8 | 27 to 29 | 30 to 35 | > 35 |
| Porto Santo | 10 to 11 | 8 to 9 | < 8 | 26 to 27 | 28 to 31 | > 31 |
Criteria for the Azores Archipelago
| Warning | Parameter | Yellow | Orange | Red | Unit | Notes |
|---|---|---|---|---|---|---|
| Wind | Mean Wind Speed | 65 - 74 | 75 - 87 | > 87 | km/h | |
| Maximum Wind Gust | 85 to 100 | 101 to 130 | > 130 | km/h | ||
| Precipitation | Rain/Showers | 10 to 20 | 21 to 40 | > 40 | mm/1h | Millimetres in one hour |
| 25 to 40 | 41 to 60 | > 60 | mm/6h | Millimetres in 6 hours | ||
| Snow | Snowfall with accumulation | 1 to 5 | 6 to 15 | > 15 | cm | Altitude below 1000 m |
| 1 to 10 | 11 to 30 | > 30 | cm | Altitude from 1000 to 1600 m | ||
| 5 to 25 | 26 to 50 | > 50 | cm | Altitude above 1600 m | ||
| Thunderstorm | Electrical discharges; Showers; Hail; Maximum Wind Gust. |
a) | b) | c) | Expected phenomena by warning level | |
| Fog | Visibility | *≥ 48h | *≥ 72h | *≥ 96h | * - duration | |
| Hot Weather | Maximum Temperature | # to # * | # to # * | > # * | ºC | * - duration ≥ 48 hours |
| Cold Weather | Minimum Temperature | # to # * | # to # * | < # * | ºC | * - duration ≥ 48 hours |
| Rough Sea | Significant Wave Height | 6 to 7 | 7 to 9 | > 9 | m |
# - Values for each Group shown in the following table.
| Group | Minimum Temperature | Maximum Temperature | ||||
|---|---|---|---|---|---|---|
| Yellow | Orange | Red | Yellow | Orange | Red | |
| Eastern | 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 |
| Western | 8 to 5 | 4 to 0 | < 0 | 28 to 29 | 30 to 31 | > 31 |
Expected phenomena by Thunderstorm Warning level
| Thunderstorm Warning | Expected phenomena |
|---|---|
| a) Yellow | Favourable conditions for the occurrence of localised meteorological phenomena, such as: thunderstorm; locally heavy precipitation, with accumulation between 10 and 20 mm in 1 h; hail with diameter < 2 cm; wind gusts between 70 and 90 km/h. |
| b) Orange | Favourable conditions for the occurrence of localised severe meteorological phenomena, such as: thunderstorm; locally very heavy precipitation, with accumulation between 20 and 40 mm in 1 h; hail with diameter ≥ 2 cm; wind gusts equal to or greater than 90 km/h. |
| c) Red | Favourable conditions for the occurrence of localised extreme meteorological phenomena with potential for major impacts, such as: thunderstorm; very heavy precipitation, with accumulation ≥ 40 mm in 1 h; large hail; highly destructive wind gusts. |
Likely Impacts by warning
| Warning | Yellow | Orange | Red |
|---|---|---|---|
 Snow |
Disruption caused by snowfall with accumulation and possible ice formation (e.g., restricted or closed roads, damage to structures or trees, disrupted local supplies). | Moderate disruption caused by snowfall with accumulation and possible ice formation (e.g., restricted or closed roads, damage to structures or trees, disrupted local supplies). | Severe disruption caused by snowfall with accumulation and possible ice formation (e.g., closed roads, damage to structures or trees, disrupted local supplies). |
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