TRENDS for the week of 11 to 17 Jan 2021
-- Temperatures will average near normal to 1 deg above normal.
-- Rainfall will average near normal to 25% above normal.
-- Sunshine will average 50 to 75 per cent of normal.
FORECASTS
TODAY will be overcast with occasional rain, becoming heavier by afternoon before ending from west to east for a time this evening, highs 8 to 11 C. About 10-15 mm rain expected.
TONIGHT some clearing will spread into parts of Ulster where it may turn quite cold briefly, lows 2 to 4 C. Otherwise it will stay overcast in other regions with fog and occasional light to moderate rain, lows 6 to 8 C.
TUESDAY will see some further rainfalls of 10-15 mm with occasional heavy showers, and moderate southwest winds. The colder air in Ulster will be pushed back to the east by mid-day and all regions will then be around 9 to 12 degrees.
WEDNESDAY the rain will end by mid-day (about 20-30 mm additional expected) and it will begin to clear late in the day. Temperatures steady 10-12 C then falling slowly to around 7 C.
THURSDAY will be partly cloudy and a bit colder with lows near 4 C and highs near 8 C.
FRIDAY will be breezy and mild with occasional rain, southwest winds 50 to 80 km/hr, highs near 10 C.
The OUTLOOK for the weekend is for westerly winds and slowly falling temperatures in several stages, as winds become more northwesterly. Some showers are likely at times, with readings near 8 C on Saturday and 6 C by Sunday.
Next week looks colder again, with winds more northerly, highs only in the range of 3 to 6 C and possibly even colder, depending on which guidance prevails, as some of the charts by mid to late week (20th-23rd) show very cold air even a bit colder (in the daytime at least) than what was experienced last week, potentially some snow showers with that if not intervals of snow, much depends on wind directions and embedded low pressure in this arctic air, and daytime readings in the range of -2 to +2 C. This is certainly not "carved in stone" yet, but has been a fairly frequent theme of almost all guidance from time to time in the past few days. Then the least certain aspect of all is how long this second cold spell might last once underway, there were early suggestions it would be about a 3-4 day event but now it's looking possibly more like a week to two weeks.
FORECASTS
TODAY will be overcast with occasional rain, becoming heavier by afternoon before ending from west to east for a time this evening, highs 8 to 11 C. About 10-15 mm rain expected.
TONIGHT some clearing will spread into parts of Ulster where it may turn quite cold briefly, lows 2 to 4 C. Otherwise it will stay overcast in other regions with fog and occasional light to moderate rain, lows 6 to 8 C.
TUESDAY will see some further rainfalls of 10-15 mm with occasional heavy showers, and moderate southwest winds. The colder air in Ulster will be pushed back to the east by mid-day and all regions will then be around 9 to 12 degrees.
WEDNESDAY the rain will end by mid-day (about 20-30 mm additional expected) and it will begin to clear late in the day. Temperatures steady 10-12 C then falling slowly to around 7 C.
THURSDAY will be partly cloudy and a bit colder with lows near 4 C and highs near 8 C.
FRIDAY will be breezy and mild with occasional rain, southwest winds 50 to 80 km/hr, highs near 10 C.
The OUTLOOK for the weekend is for westerly winds and slowly falling temperatures in several stages, as winds become more northwesterly. Some showers are likely at times, with readings near 8 C on Saturday and 6 C by Sunday.
Next week looks colder again, with winds more northerly, highs only in the range of 3 to 6 C and possibly even colder, depending on which guidance prevails, as some of the charts by mid to late week (20th-23rd) show very cold air even a bit colder (in the daytime at least) than what was experienced last week, potentially some snow showers with that if not intervals of snow, much depends on wind directions and embedded low pressure in this arctic air, and daytime readings in the range of -2 to +2 C. This is certainly not "carved in stone" yet, but has been a fairly frequent theme of almost all guidance from time to time in the past few days. Then the least certain aspect of all is how long this second cold spell might last once underway, there were early suggestions it would be about a 3-4 day event but now it's looking possibly more like a week to two weeks.
-- Peter O'Donnell for IWO