Guidance has bolstered support for the forthcoming nor’easter storm system set to track into Atlantic Canada later this coming weekend, impacting parts of S QC and the Maritimes who have little enthusiasm for added precip given the spring pattern to date.

Remnants of the previous storm have delivered substantial rains to Cape Breton over the last while, tallying up more than 100mm for YQY Sydney over a 3-day period and bringing it’s May total to 154.7mm against average values of 100.9mm for the month as a whole. Another unwelcome notch in the waterlogged bedpost for Eastern Canada.

As has been the case with prior systems this one may not be in a great hurry to exit the region,  potentially lingering into the mid-week timeframe as it weakens.

06z GFS @ hour 84 / 108 / 132:


WPC total QPF for days 1-5:


A large-scale regime change should unfold beyond this point as upper ridging shunts eastward and brings warmer air into the GL and Eastern USA where troughiness has held sway of late.

This will blunt the notable negative temp departures which have dictated the pace for these areas through the early-mid part of the month.

Temp anomalies for the past 7 days:


Running mean temp anomalies for days 7-14 via the 00z GFS ensembles:


00z EPS 500mb height anomalies @ hour 192:


The ULL digging into the western USA in the above image could herald some severe weather as it treks E/NE towards the 23rd or so, tempering the eastern ridge to some degree as it does.