RAINFALLTEMPERATURESRIVER FLOWGROUNDWATER & SOILAIR QUALITYLONGER FORECAST

April 2019

April 2019

A dogged southerly wind in April gave us rude flashes of winter, distracting daytime temperatures and peppering the Wairoa area with showers. The Heretaunga Plains, Tangoio and Ruahine Range missed out on much of the rain while areas to the south saw totals closing in on the April norm.

Soil moisture followed a similar wet, dry, normal pattern as you head from north to south, while river flows were below normal for all but the very far north and very far south.

Groundwater levels in the main aquifers remain subdued with little help from above. Air quality can be problematic in the months ahead but no worries so far as we mount the shoulders of winter.

Kathleen KozyniakPrincipal Scientist - Climate and Air

SUMMARY April 2019

A struggle to reach the monthly averages.

This is a summary of the regions rainfall, river flows, ground water, air quality and soil moisture levels. Data and images provided by HBRC.

May to July Forecast

Temperature Above averageRain Below or near normal River flows Below or near normalSoil moisture Below or near normal

source : NIWA

For more informationwww.hbrc.govt.nzP: 06 835 9200

RAINFALL

Near normal, though dry from the Heretaunga Plains to the Ruahine Range.

Percentage of normal April rainfall (30 year average)

For areas in the region:Waikaremoana 115%Northern HB 119%Tangoio 72%Kaweka 90%Ruahine 73%Heretaunga Plains 67%Ruataniwha Plains 90%Southern HB 85%Hawke’s Bay Region 89%

TEMPERATURES

Average nights but cool days.

Mean Difference from NormalMaximum Temperature: -0.8°CMinimum Temperature: 0.4°C

Mean Daily Maximum: 17°CMean Daily Minimum: 9°CHighest Daily: 25.8°CLocation: Napier Aero AWS Lowest Daily: -1.9°CLocation: Taharua

RIVER FLOW

Percentage of average April flows for areas in the region:

Northern Coast – Mahia 103% Northern HB – Hangaroa River 66%Northern HB – Wairoa River 123%Northern HB – Waiau River 59%Mohaka 47% Esk-Central Coast 78% Tūtaekuri 63% Karamu 62% Ngaruroro - Kuripapango 38% Ngaruroro - Chesterhope 32% Southern Coast 80% Tukituki – Tukipo River 16%Tukituki – Tukituki River 34%Porangahau 18%Hawke’s Bay Region 59%

GROUNDWATER &SOIL MOISTURE

Groundwater:

Heretaunga basin: Mostly normal to below normal levels

Ruataniwha basin: Mostly normal to below normal levels

Secondary basins: Mostly normal water levels

Soil Moisture: Near or below normal

AIR QUALITY

Thumbs up, no exceedances.

Figure 1: PM10 levels in the Napier, Hastings and Awatotoairsheds during April 2019.

PM10 exceedances:The National Environmental Standard (NES) for particulate matter (PM10) of 50 micrograms per cubic metre (24 hour average) was not exceeded in the Napier, Hastings and Awatoto airsheds in April 2019.

The monitoring sites are located at: 2019 Totals• Marewa Park - Napier airshed 0• St Johns College - Hastings airshed 0• Waitangi Road - Awatoto airshed 0

Further information is available at www.hbrc.govt.nz

LONGER FORECAST

A weak El Niño trundles on in the central Pacific and may linger through the winter. The unusually warm sea temperatures in the Bay have cooled for now and that, combined with an outlook of westerlies, favours rainfall below or near normal.

Despite the cooling seas in our parts, temperatures should hold up around or above normal as we get foehn winds from a westerly flow with only a slight inclination to southerly.

Kathleen KozyniakPrincipal Scientist - Climate and Air