Ensembles have been indicating robust upper-level blocking should become established for the early part of May, with amplification of the NA pattern in a general trough/ridge/trough configuration as strong H5 ridging develops downstream towards Greenland.

nao

00z EPS 500mb height anomalies @ hour 168:

ecmwf-ens_z500a_namer_8

This evolution may support a deepening storm through the eastern portion of the country into late week and next weekend, as briefly discussed in a previous entry.

Track and details have varied from model-to-model and run-to run with a path through QC and the Maritimes still plausible. There has been some discontinuity as to how consolidated this potential threat may be or if it ejects as a series of flatter waves.

Low clustering from the 00z GFS ensembles, hour 156:

gefs_slp_lows_east_27

The interpretation from the latest 00z deterministic ECMWF, hour 144:

ecmwf_z500_mslp_us_7

Hour 168:

ecmwf_z500_mslp_us_8

Between the short-range threat and this possible next advancing low the general theme continues to be tilted rather wet via the WPC, total precip for days 1-7:

p168i

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