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RECORD APRIL HEAT & EARLY SUMMER PREVIEW


Well what a way to end the warmest April, in recorded history in St. John's!
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Interestingly enough, in a month when we usually see 27 cm of Snow, yesterday was the only measurable snowfall in Metro. It really was a fantastic April. In the end, that mid-month warm stretch with those two 20° degree days was enough to bump us over that record hump!
 
This April finished with an temperature average of 5.4°, which is an all time monthly record. The previous YYT weather station record for April was 4.3°, set back in 1986. However the all time record we beat, was from the OLD St. John's Weather station, which was 5.3° set back in 1889!
 
That April of 1889, was really nice. St. John's had three 20° days! What kind of a summer did they have? Well, May (+3.0°) June (+3.4°) July (+2.7°) August (+1.7°) and September (+2.4°) all averaged above normal temperatures! It was also quite a dry summer, with about 300 mm in that 5 month span. Now days, we typically see ~530 mm in that time. So it will be really interesting to see if it plays out the same way. 
 
PATTERN CHANGE COMING 
 
In the short term, High pressure will be the main player over the next 48 hours across the Province, with a taste of Sun for most. However, it's another area of High pressure which is strengthening off to our North and East over Greenland, that I'm watching closely.
 
It's been awhile since I've talked about the NAO, or the "North Atlantic Oscillation", but over the next week or so, it's going to be influencing us here in NL yet again. The NAO is a measurement of the pressure patterns over the North Atlantic. It's been positive for awhile, but is forecast to tank into a negative phase over the next week.  
MayNAO.PNG
 
When the NAO goes into a negative phase, we typically see Higher than normal pressure over Greenland. That higher than normal pressure, can lead to a bit of a road block for systems trying to cross the North Atlantic and head towards the UK. So instead, systems tend to sit and spin for days and days in our neck of woods. And that's just what's on the menu... a blocking High over Greenland and low stuck spinning to our South.

May01122.JPG 
 
It appears a Low approaching from the Southeast on Wednesday will wrap into Newfoundland and then sit and spin from Thursday, possibly right into the Weekend. It's not a bad setup for Central & Western Newfoundland or most of Labrador. However it's not great news for Eastern Newfoundland, which will likely be dealing with an Easterly onshore Atlantic flow. Cooler temps, cloud cover, drizzle & yes fog patches are expected to be featured in the forecast, for later in the week.
 
Fog patches by the way, are not unexpected this time of year in St. John's & Eastern Newfoundland. A great Twitter post from Rodney Barney (@rcbstormpost) at the Gander Weather Office this morning, who pointed out: Climatologically, May is the foggiest month of year in St. John's.
 
FogMay.png
 
LONG LONG RANGE
 
Alright, so let's look past this short term pattern change and take a peek at what could be on the menu for this coming Summer across NL. Environment Canada Climatologists have just released their outlook for May, June & July across the Country. As you can see, they're predicting a wide spread warmer than normal Summer, right across Canada. I can tell you this trend is expected to continue right into August as well. Most of the other Summer outlooks I've read, have had a similar idea: Normal to warmer than normal temperatures.

TempsMay0112.PNG 
 
In terms of precipitation, normal seems to be the idea for the next 3 or 4 months. Again, the Environment Canada outlook matches up with some of the other outlooks I've looked at, including the Long Range European model interpretations.

PrecipMay0112.PNG 
 
But of course... this is Newfoundland and Labrador and only time will tell for sure!

Ryan

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