Margarida Belo-Pereira

<p>Aviation turbulence remains one of the leading causes of weather-related aviation accidents. Therefore, turbulence prediction is a major concern of aviation forecasters.</p><p>The performance of several turbulence diagnostics derived from ECMWF forecasts is evaluated over Portuguese Flight Information Regions (FIR) and surrounding areas, for the period February 2020 to April 2021, excluding May and June. In addition, the algorithm developed and used operationally by aviation meteorologists at IPMA to forecast moderate and severe turbulence over Portuguese FIRs is also discussed. The forecasts were compared with turbulence observations from special air reports and DEVG data from AMDARs received at the Portuguese MWO.</p><p>The objective verification approach in this paper uses not only the Relative Operating Characteristic curves but also novel measures such as the recently proposed Symmetric Extreme Dependence Index (SEDI) and Symmetric Extreme Dependence Index (SEDS). These measures are particularly suitable for assessing the forecasting skill of rare, such as moderate or greater turbulence, which accounts for 1.6% of the total data.</p><p>The vertical wind shear (VWS), DUTTON, Brown and Ellrod indices outperform the other turbulence diagnostics. In addition, VWS performs the best in terms of all verification measures. It has been found that adding a Richardson number function to these five turbulence diagnostics improves the performance of aviation turbulence forecasting. Consequently, the operational index combines these five diagnostics with the Richardson number.</p><p>Prediction of moderate and severe turbulence depends on the choice of the optimal threshold. However, this optimal threshold varies with the verification measure used. The results show that TSS and SEDI achieve a higher value for lower thresholds compared to SEDS. This is because when the contingency table becomes dominated by the correct predictions of non-events, both TSS and SEDI penalize under-prediction more than over-prediction.</p><p>Finally, the performance of the operational turbulence index and compared with the WAFS product is also illustrated for two turbulence episodes. </p>

A grand challenge from the wind energy industry is to provide reliable forecasts on mountain winds several hours in advance at microscale (∼100 m) resolution. This requires better microscale wind-energy physics included in forecasting tools, for which field observations are imperative. While mesoscale (∼1 km) measurements abound, microscale processes are not monitored in practice nor do plentiful measurements exist at this scale. After a decade of preparation, a group of European and U.S. collaborators conducted a field campaign during 1 May–15 June 2017 in Vale Cobrão in central Portugal to delve into microscale processes in complex terrain. This valley is nestled within a parallel double ridge near the town of Perdigão with dominant wind climatology normal to the ridges, offering a nominally simple yet natural setting for fundamental studies. The dense instrument ensemble deployed covered a ∼4 km × 4 km swath horizontally and ∼10 km vertically, with measurement resolutions of tens...

Sub-hourly heavy precipitation events (SHHPs) associated with regional low-pressure (RegL) systems in Portugal are a natural hazard that may have significant socioeconomic implications, namely in agriculture. Therefore, in this paper, their dynamic and thermodynamic drivers are analysed. Three weather stations were used to isolate SHHPs from 2000 to 2022. Higher precipitation variability is found in southern Portugal, with a higher ratio of extreme events on fewer rainy days. This study shows that these SHHP events are associated with low-pressure systems located just to the west of the Iberian Peninsula. These systems exhibit a cold core, particularly strong at mid-levels, and a positive vorticity anomaly, which is stronger in the upper troposphere, extending downward to low levels. These conditions drive differential positive vorticity advection and, therefore, rising motion to the east of the low-pressure systems. Moreover, at low levels, these systems promote moisture advection ...

ABSTRACT A new high-resolution daily precipitation gridded dataset over mainland Portugal, PT02, is presented. This dataset spans the period from 1950 to 2003 and is based on more than 600 stations. The data used to create the PT02 dataset was subject to a quality control, including suspicious data identification and in-homogeneity detection. The interpolation method applied to create the PT02 dataset was the ordinary kriging, which was compared with simpler techniques, namely, inverse distance weighting methods. Additionally, the performance of two ECMWF re-analyses - ERA40 and ERA-Interim is analysed over the Iberian Peninsula. For this purpose, the PT02 dataset is combined with a recent Spanish high-resolution daily precipitation gridded dataset (Spain02) to create a high resolution (0.2° × 0.2°) Iberian dataset. Several aspects of the ECMWF re-analyses were evaluated, including spatial pattern of annual mean, annual cycle and drought identification. Drought assessment is performed using the standardized precipitation index. Monthly and 5-days precipitation is evaluated using simple scores, such as bias and squared correlation. Finally, the accuracy of spatial patterns of the 5-days precipitation of ECMWF re-analyses is also assessed using the correspondence ratio, defined as the ratio between the area where both datasets represent precipitation and the area where at least one of the datasets depicts precipitation. In general, despite a similar performance in some aspects, ERA-Interim outperforms ERA40 over the Iberian Peninsula. The northwest-southeast contrasts in the geographical distribution of mean annual precipitation are well captured by the two re-analyses. However, in the vicinity of mountainous regions, total amounts are strongly underestimated, mainly by ERA40. This is consistent with the misrepresentation of the sharp orographic features of Iberia due to the coarser resolution used by ERA-Interim and in particular by ERA40. The strong annual cycle over the Iberian Peninsula is reasonably well captured by the two re-analyses. However, its amplitude is underestimated by both datasets. On average over the Iberian Peninsula, the frequency of days with precipitation is overestimated by the two re-analyses, mainly by ERA-Interim, while both re-analyses, mostly ERA40, underestimating the number of days with precipitation exceeding 10 mm/5-days. Despite the poor skill to predict events with higher precipitation amounts (exceeding 20 mm/5-days), ERA40 and ERA-Interim demonstrate a greater ability to estimate correctly the peak locations of such events, with ERA-Interim being superior to ERA40. Given the large variety of precipitation regimes in the Iberian Peninsula and a strong dependency of precipitation on orography, PT02 and its combination with Spain02 will be a valuable contribution to the validation of increasingly high resolution re-analyses and climate simulations. The PT02 dataset is available from the Portuguese Meteorological Service (Instituto de Meteorologia, IM) website, for non-commercial purposes (see www.meteo.pt).

Synthesis - The production of an accurate analysis is one important goal of modern NWP centers, where sophisticated data assimilation techniques (such as variational methods) have been implemented. However, this task is not straightforward, since the real state of the atmosphere is never exactly known. One of the main difficulties in data assimilation is caused by the fact that the degrees of freedom of the modern NWP models (~107) are larger than the number of independent available observations (~105). Moreover, the distribution of the observation network is not uniform in space and in time. For these reasons, it is not enough to perform a spatial interpolation of observations into a regular grid. A prior information is needed in order to solve the undetermined analysis problem. In other words, it is necessary to have a first guess about the atmospheric state at all grid points. In modern data assimilation schemes, this first guess (or background) is provided by a short range forec...

Aviation turbulence remains one of the leading causes of weather-related aviation accidents. Therefore, turbulence prediction is a major concern of aviation forecasters. This paper describes the turbulence index (TURBIPMA) developed and used operationally at the Portuguese Institute of Sea and Atmosphere (IPMA), based on several diagnostics derived from ECMWF forecasts, using a new calibration approach. The forecast skill of the TURBIPMA and of individual diagnostics are evaluated using turbulence observations over the Portuguese Flight Information Regions and surrounding areas, for 12 months between February 2020 and March 2021 (excluding May and June). The forecasting skill of the predictors is discussed in terms of the Relative Operating Characteristic (ROC) curves, which is widely applied, but also in terms of novel measures such as the Symmetric Extremal Dependence Index (SEDI) and Symmetric Extreme Dependency Score (SEDS). The new measures are particularly relevant in assessin...

Sub-hourly heavy precipitation events (SHHPs) frequently underlie major meteorological hazards, but their comprehensive analysis is still lacking in Portugal. A 71-weather-station dataset for 2000–2020 is used in this article to (1) diagnose SHHPs corresponding to a 10-min precipitation event of at least 5.0 mm, (2) characterize their spatial-temporal distribution, and (3) identify their associated synoptic-scale conditions. Two synoptic types are associated with SHHPs: remote (RemL) and regional (RegL) low-pressure systems. RegL SHHPs display two marked maxima in spring and autumn, while RemL SHHPs show a single maximum in autumn. Most RegL events occur in the afternoon/evening, while RemL events show a slight bias toward midday occurrences. In the case of RemL, the wind is stronger for 2 to 3 h before and during SHHPs, veers from 180° to 210° near the event, the pressure decreases until 20 min before the event, and the wet-bulb temperature decreases around the time of the event an...

<p>The Madeira International Airport (MIA) lies on the island south-eastern coast and it is known to be exposed to wind hazards. A link between these adverse winds at MIA and the synoptic-scale circulation is established using a weather type (WT) classification. From April to September (summer period), five WTs prevail, cumulatively representing nearly 70% of days. These WTs reflect the presence of well-established Azores high, with some variations on location and strength. Although with a low frequency of occurrence (<5%), this anticyclone occasionally strengthens and extends towards Iberia, inducing anomalously strong NNE/NE up to 3-5 km over Madeira. The most severe and longer-lasting wind conditions at the MIA, with a higher frequency of gusts above 35 kt, are driven by this synoptic-scale pattern and are more common in summer. An episode of adverse winds at the MIA is analyzed, illustrating the occurrence of upstream stagnation, flow splitting, and lee wake formation. The upstream conditions include a low-level inversion, strong NNE/NE winds near and above the inversion and a Froude number less than 1. AROME model predicted the occurrence of downslope winds, in association with a large-amplitude mountain wave. At this time, the strongest wind gusts were registered and a missed approach occurred. The wind regime in different places of the island suggests that these conditions are relatively frequent, mostly in summer. Lastly, this study provides an objective verification of the AROME wind forecasts, for a 3-year period and from June to August.</p>

The Madeira International Airport (MIA) lies on the island’s south-eastern coast and it is known to be exposed to wind hazards. A link between these adverse winds at MIA and the synoptic-scale circulation is established using a weather type (WT) classification. From April to September (summer period), five WTs prevail, cumulatively representing nearly 70% of days. These WTs reflect the presence of well-established Azores high, with some variations on location and strength. Although with a low frequency of occurrence (<5%), this anticyclone occasionally strengthens and extends towards Iberia, inducing anomalously strong NNE/NE up to 3–5 km over Madeira. The most severe and longer-lasting wind conditions at the MIA, with a higher frequency of gusts above 35 kt, are driven by this synoptic-scale pattern and are more common in summer. An episode of adverse winds at the MIA is analysed, illustrating the occurrence of upstream stagnation, flow splitting, and lee wake formation. The ups...

On 23/12/2009, windstorm Xola struck mainland Portugal, causing serious damage in a small area north of Lisbon (Oeste region) and in the south region, inflicting economic losses of over EUR 100 million. In both areas, several power towers, designed to withstand up to 46 m s−1 winds, were destroyed. The causes of these two distinct damaging wind events were investigated. Xola was revealed to have a prominent cloud head and a split cold front structure. In the southern region, the damages were due to downburst winds, associated with a mesovortex, observed in a bow echo line triggered by an upper cold front. The cloud head presented several dry air intrusion signatures, co-located with tops progressively lowering towards the hooked tip. This tip revealed features consistent with the presence of slantwise convection, the descending branches of which may have been strengthened by evaporating cooling. At the reflectivity cloud head tip, a jet streak pattern was identified on weather radar...

Thermal conditions in mainland Portugal were evaluated using a new hourly database over the recent period of 2000–2018 (19 years). The number of hours within each different temperature interval was calculated from the long-term means of the hourly temperatures of a network of 63 meteorological stations. A geostatistical approach, using elevation, distance to coastline and latitude, was subsequently applied to provide gridded patterns at a high spatial resolution (1 km grid spacing). Eight fruit species (almond tree, carob tree, chestnut tree, citrus fruits, cork oaks, holm oaks, olive trees, and grapevines) were selected to assess their hourly thermal growing conditions. The results highlight the strong spatial variability of temperature levels in mainland Portugal, providing new insights into their spatial distribution. The number of hours in the year with cool conditions (4–12 °C) is higher in the northern-central regions, mainly in mountainous areas. Additionally, the number of h...

A hard landing incident in Pico Aerodrome (LPPI) involving an Airbus A320-200 aircraft is investigated using airborne observations and forecasts of the AROME (Applications of Research to Operations at Mesoscale) model. A second flight is also analyzed. The severity of the wind shear during both flights is quantified using the intensity factor “I” that is based on aerial data and recommended by ICAO (International Civil Aviation Organization). During Flight 1, 36% of the landing phase (below 2100 ft) occurred under “severe” wind shear conditions and 16% occurred under “strong” conditions. Upstream characteristics included southwest winds, stable stratification and a Froude number close to 1. According to the AROME model, these circumstances triggered the development of vertically propagating mountain waves, with maximum vertical velocities above 400 ft/min and exceeding 200 ft/min in the flight path. These conditions, together with the severe wind shear, may have caused the incident....

Abstract On 7 December 2010 a long lived convective storm formed southwest of Lisbon in an instability line that developed in a very moist and unstable airmass, in the circulation of an extra-tropical cyclone propagating north-eastwards. This storm crossed the Lisbon district and spawned an F3 tornado a few dozens of kilometers to the northeast. Several parameters evaluating buoyancy, available moisture and vertical wind shear, were derived from Lisbon rawinsonde and ECMWF analyses, highlighting an environment that is favourable for tornadic development. The tornado touchdown occurred by 14:15 UTC, lasting for about 45 min and producing an exceptionally long damage path of around 54 km, according to the damage survey. It caused about 18 million Euros damage, > 40 injured people, but no fatalities. This storm had a very long lifetime of at least 5 h, intensified inland, sustained strong updrafts during, at least, 1 h and hold large hail cores as observed on radar. Exhibiting several supercell like features, it also produced intense lightning, with a predominance of cloud-to-ground flashes before the tornado touchdown and intra-cloud flashes during the tornado lifetime. Furthermore, in high resolution visible satellite imagery, a pattern of feeder clouds was identified one hour before tornadogenesis. This pattern has been associated to storm intensification and the onset of severe weather.

This paper describes the operational wave forecasting system that has been implemented at the Portuguese Institute for Ocean and Atmosphere (IPMA) along the west coast of the Iberian Peninsula. This system is based on the Simulating WAves Nearshore (SWAN) model, is forced at the boundaries by the Limited-Area Wave (LAW) model forecasts generated by the European Centre for Medium-Range Weather Forecasts (ECMWF) and by the 10m wind fields from the ALADIN atmospheric model. Moreover, the performance of three SWAN whitecapping parameterisations is evaluated. This evaluation is performed for significant wave height, mean wave period and mean wave direction forecasts through comparisons with observations from four buoys over a six month period. Finally, it gives a short evaluation of the operational version of SWAN model at IPMA during the recent Christina Storm.

c.andrade@ipt.pt), (2) Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal, (3) Instituto Português do Mar e da Atmosfera, Lisboa, Portugal (margarida.belo@ipma.pt) This paper is focused on analysing the temporal and spatial variability of droughts in Iberia and five regions, for the period 1951-2007, for four observational precipitation gridded datasets, namely, GPCC, CRU, ECA and a high resolution (0.2 • ×0.2 •) dataset. Droughts are assessed using the Weighted Anomaly of Standardized Precipitation (WASP) Index for 3-, 6-and 12-month time-scales. The results show that WASP-Index and the widely used Stan-dardized Precipitation Index (SPI) are highly correlated for the three time-scales. The performance of lower resolution precipitation datasets, when they are applied to drought detection, is also dis-cussed. The longest and most intensive droughts are recorded-06. These major drought sp...

ABSTRACT In this study precipitation from a high resolution WRF climate simulation is presented and evaluated against daily gridded observations in the Iberian Peninsula. The simulation corresponds to a dynamical downscaling of ERA-Interim, in the period 1989–2009, performed with two nested grids, at 27 and 9 km horizontal resolution. The higher resolution simulation indicates a significantly improved representation of Iberian precipitation fields, at all timescales, with emphasis on the representation of variability and of extreme weather statistics. Results compare well with recent studies with other models and/or for other regions, further supporting the use of WRF as a regional climate model. Copyright  2012 Royal Meteorological Society

The work described here evaluates precipitation from ERA-40 and ERA-INTERIM over the Iberian Peninsula. This evaluation focus on annual, monthly and 5-days timescales. A drought analysis is also performed using the standardized precipitation index. The quality of the re-analyses is assessed using a high resolution daily gridded dataset, which results from the merge of a Spanish and a Portuguese new

ABSTRACT The precipitation distribution in the Iberian Peninsula has a high spatial variability, with a high North-south disparity, as well as large inter and intra-annual fluctuations. In recent years the development of Regional Climate models with increasing complexity in cloud and precipitation subgrid-scale parameterisations allow for a more accurate assessment of precipitation on large temporal time scales. The Weather Research and Forecast (WRF-ARW) model, was used for simulations of precipitation over Europe and Iberian Peninsula. A first simulation was carried out for the European domain of the Cordex project, corresponding to a 50km resolution. A second high regional resolution simulation was achieved by using two nests centred on the Iberian Peninsula with 27km and 9km resolution and two-way nesting. Era-Interim was adopted as initial and boundary conditions in all the simulations. These results were compared with hourly observations from 300 INAG (Portuguese water management authority) stations and daily data form PT02 and Spain02 (Portuguese and Spanish Meteorological 20km gridded dataset). The higher resolution simulation indicates a significantly improved representation of Iberian precipitation fields, at all timescales, with emphasis on the representation of variability and of extreme weather statistics. Results compare well with recent studies with other models and/or for other regions.

On 23/12/2009, windstorm Xola struck mainland Portugal, causing serious damage in a small area north of Lisbon (Oeste region) and in the south region, inflicting economic losses of over EUR 100 million. In both areas, several power towers, designed to withstand up to 46 m s −1 winds, were destroyed. The causes of these two distinct damaging wind events were investigated. Xola was revealed to have a prominent cloud head and a split cold front structure. In the southern region, the damages were due to downburst winds, associated with a mesovortex, observed in a bow echo line triggered by an upper cold front. The cloud head presented several dry air intrusion signatures, co-located with tops progressively lowering towards the hooked tip. This tip revealed features consistent with the presence of slantwise convection, the descending branches of which may have been strengthened by evaporating cooling. At the reflectivity cloud head tip, a jet streak pattern was identified on weather radar, with Doppler velocities exceeding 55 m s −1 , just 400 m above ground. This signature is coherent with the presence of a Sting jet, and this phenomenon was associated with the strongest wind gusts (over 40 m s −1) and the largest damages in the Oeste region.

A hard landing incident in Pico Aerodrome (LPPI) involving an Airbus A320-200 aircraft is investigated using airborne observations and forecasts of the AROME (Applications of Research to Operations at Mesoscale) model. A second flight is also analyzed. The severity of the wind shear during both flights is quantified using the intensity factor "I" that is based on aerial data and recommended by ICAO (International Civil Aviation Organization). During Flight 1, 36% of the landing phase (below 2100 ft) occurred under "severe" wind shear conditions and 16% occurred under "strong" conditions. Upstream characteristics included southwest winds, stable stratification and a Froude number close to 1. According to the AROME model, these circumstances triggered the development of vertically propagating mountain waves, with maximum vertical velocities above 400 ft/min and exceeding 200 ft/min in the flight path. These conditions, together with the severe wind shear, may have caused the incident. During the second flight, a wake with lee vortices and reversed flow developed in the region of the flight path, which is consistent with a low upstream Froude number and/or with the flow regime diagram of previous studies. During the approach phase of this flight, "severe" wind shear conditions were absent, with "strong" ones occurring 4% of the time. It predominantly displayed "light" conditions during 68% of this phase. As a result of the comparison between "I" and the AROME turbulence indicators, preliminary thresholds are proposed for these indexes. Lastly, this study provides an objective verification of AROME wind forecasts, showing a good agreement with airborne observations for wind speeds above 10 kt, but a poor skill for weaker winds.

The 7–8 January 2015 persistent fog episode at Lisbon international airport is analysed. Its persistence was atypical of the local climate (second longest episode since 2004) and caused significant air traffic disruptions. Furthermore, the performance of two operational models (European Centre for Medium-range Weather Forecasts (ECMWF) and Applications of Research to Operations at Mesoscale (AROME)) used at the Portuguese Weather Service is assessed not only for the selected fog episode, but also for the extended winters (November to March) of 2013/2014 and 2014/2015. This episode developed under the following conditions: (1) the occurrence of a strong and persistent midwinter anticyclone over Iberia, driving favourable conditions for the formation of radiation fog; (2) a short interruption of the anticyclonic circulation by a kata-cold front on the day before, favouring the development of fog/low stratus clouds, which persisted until dawn on 7 January over the Tagus valley; (3) low-tropospheric easterly/northeasterly winds, favouring the drift of fog patches from the Tagus towards Lisbon. At the nearest grid point to Lisbon airport, both ECMWF and AROME were able to capture fog occurrence, but were unable to predict its persistence throughout the episode. Moreover, both models overestimated the 2 m temperature and dew point depression. Low cloud cover and horizontal visibility from ECMWF revealed higher skill in fog prediction than that derived from AROME. Nonetheless, a modified version of the Fog Stability Index based on AROME was proven to be a more skilful fog predictor, also outperforming other predictors based on ECMWF. These conclusions are also supported by an objective verification over a two-winter period.

This study presents an objective verification of different icing algorithms for two periods from 5 December 2012 to 17 April 2013 and from 9 October to 11 December 2013. The predicted icing potential and severity are evaluated against pilot reports of aircraft icing below 23 000 feet over Eastern United States. The icing algorithms are applied to the deterministic forecasts of European Centre for Medium-Range Weather Forecasts (ECMWF). Two of these algorithms are based only on forecasts of temperature (T) and relative humidity (RH), but the first uses fixed thresholds and the second uses a fuzzy logic approach. Although the second algorithm detects less icing events, it is more efficient with respect to the warning area, i.e. it forecasts icing over a smaller percentage of the airspace than the first algorithm. The impact of adding information from cloud liquid water (CLW) content and/or vertical velocity in the fuzzy logic scheme is assessed. Algorithms using T, CLW and vertical velocity as predictors are also tested. Most of the algorithms reveal a good performance in discriminating between icing and no-icing conditions, but are less skilful in forecasting the icing severity. The results also show that the use of CLW is essential to avoid issuing too many warnings. Moreover, the algorithm combining T, RH, CLW and vertical velocity attains the best performance. This algorithm, SFIP O , has been operational at the Portuguese Meteorological Watch Office since June 2013, and an example of a severe icing episode in February 2014 over mainland Portugal is presented. KEY WORDS aircraft icing; ECMWF forecast; fuzzy logic algorithm; cloud liquid water; PIREP

In the present study, the SWAN model was employed to estimate the wave field on an open sandy beach at the west coast of Portugal. It is the purpose of this work to evaluate the sensitivity of nearshore wave propagation modelling to (i) the wind field resolution, (ii) the type of information used at the offshore boundary to drive the simulations, and (iii) the whitecapping formulation used by the wave model. Wave measurements from an acoustic Doppler current profiler (ADCP) sensor moored in 17 m depth (datum), and operating during a rather stormy period, were used to model comparisons. The comparison showed that no significant differences in the results were found between the two wind field resolutions tested and also that an improvement was observed when the model of van der Westhuysen et al. (2007) is used for the whitecapping dissipation, instead of the default formulation by Komen et al. (1984).Dans la présente étude, le modèle SWAN a été utilisé pour estimer le champ des vagues sur une côte sableuse de la côte Ouest du Portugal ouverte sur l’Océan Atlantique. Cette étude vise à évaluer la sensibilité de la modélisation de la propagation des vagues en zone côtière (i) à la résolution du champ de vent, (ii) au type d’information utilisé pour imposer les conditions sur la frontière maritime et (iii) à le formulation utilisé dans le modèle pour la dissipation due au moutonnement. Les mesures des vagues ont été faites avec un capteur ADCP mouillé par 17 m de profondeur, exploité pendant une période englobant deux épisodes de tempête. La comparaison a permis de montrer qu’il n’y a pas de différences significatives entre les deux résolutions du champ de vent testées, et également qu’une amélioration est observée lorsqu’ est utilisé le modèle van der Westhuysen et al. (2007) pour la dissipation par moutonnement à la place de la formulation par défaut de Komen et al. (1984).

In this work we present the Climate Atlas of mainland Portugal for the 1971-2000 period. This atlas provides monthly climatology of temperature (mean, minimum, maximum temperature) and precipitation. Moreover, the monthly number of frost days (days with minimum temperature below 0°C), tropical nights (minimum temperature above 20°C), hot days (maximum temperature above 25°C) and very hot days (maximum temperature above 30°C) are computed. The monthly number of rainy days (>= 1mm), heavy precipitation days (>= 10mm) and very heavy precipitation days (>= 30mm) are also presented. The data used in this work includes 61 climatological stations and 268 rain gauges, considering the quality control analysis. Only stations with at least 20 years of data in this thirty-year period are used. Additionally, spatial consistency of monthly values and visual inspection of time series plots are performed. The 100 meters resolution gridded maps are obtained using advanced geostatistical interpolation methods, namely ordinary and residual kriging. In the last case, the predictor variables are altitude and distance to coast. The validation of interpolation process, specifically the semivariogram modelling and neighbourhood searching, is done not only optimizing the cross-validation errors, but also, by visual analysis and expert examination of the prediction maps.