A vigorous upper low will steadily move into the west coast through the late week period, driving another round of unsettled weather and convective rainfall. This may re-aggravate flooding conditions in some parts of the region before the disturbance moves E/SE next week.

06z GFS @ hour 36 / 48 / 60 / 72:

gfs_mslp_pcpn_frzn_nwus_6gfs_mslp_pcpn_frzn_nwus_8gfs_mslp_pcpn_frzn_nwus_10gfs_mslp_pcpn_frzn_nwus_12


As JJ and I noted yesterday, a nor’easter type low is set to impact parts of the east this weekend where flooding has also been a dominant issue. NB, PEI & NS could be the primarily-impacted Provinces but parts of QC & ON could also see some associated precip.

00z CMC @ hour 96 / 108 / 120:

I_nw_EST_2017051000_096I_nw_EST_2017051000_108I_nw_EST_2017051000_120


The early portion of May 2017 has delivered markedly colder-than-normal weather for a swath of Central Canada into the Midwest USA while warmth has influenced AB & SK.

Month-to-date temp anomalies:

ncep_cfsr_noram_t2m_anom

A pattern shift looks as if it could occur in the medium range as upper-level ridging builds eastward and the trough in the west moves farther inland while the deep -NAO abates.

00z EPS 500mb height anomalies @ hour 240 / day 10:

ecmwf-ens_z500a_namer_11

There’s some suggestion from the ensembles that this ridge could be squashed in the extended 11-15 day timeframe but the usual disparity is in play at this range.

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