Closed Cell Events

Table 2 lists case dates for closed cell events.

Table 2 Case dates selected for LASSO-ENA for its closed cellular stratocumulus events.

Case

Date

Description

1

2015-10-20

  • Extensive stratocumulus cloud event under easterly winds

  • Multiple periods having radar signatures of subcloud drizzle

  • Episodic breaks in the cloud field north of the islands

  • 5-day air mass back-trajectory from the U.S. northern central plains

2

2016-03-01

  • Widespread stratocumulus under southerly low-level flow

  • Increasing presence of subcloud precipitation after midday

  • 5-day air mass back-trajectories originated over the central North Atlantic

3

2016-03-08

  • Drizzling, asymmetric stratocumulus deck associated with southerly flow

  • More intense drizzle was observed around midday

  • The 5-day air mass back-trajectories originated in the central North Atlantic

4

2016-07-02

  • A drizzling stratocumulus deck under northeasterly flow

  • The strongest drizzle signatures occurred prior to midday

  • The cloud deck showed signs of erosion prior to 12 UTC, but re-established itself quickly and persisted throughout the remainder of the event

  • The 5-day air mass back-trajectories originated in the western North Atlantic

5

2016-10-15

  • A widespread stratocumulus deck

  • Low-level flows were from the northeast and east

  • The 5-day air mass back-trajectory originated over the U.S. plains via the central Atlantic

6

2016-11-15

  • A multi-day stratocumulus event with an interval of open cell type conditions

  • Ubiquitous precipitation observed throughout the event

  • 5-day air mass back-trajectories originating near Nova Scotia

7

2016-11-16

  • A multi-day stratocumulus event with an interval of open cell type conditions

  • Ubiquitous precipitation observed throughout the event

  • 5-day air mass back-trajectories originating near Nova Scotia

8

2016-11-19

  • Stratocumulus with embedded stronger precipitating cells

  • Northwesterly low-level winds, with additional upper-level clouds around midday

  • 5-day air mass back-trajectories originating local to the ENA site

9

2017-07-18

  • AN ACE-ENA campaign event with a G-1 aircraft mission

  • Closed cell stratocumulus under moderate northeasterly flow

  • 5-day air mass back-trajectories originated local to the ENA site

10

2018-01-25

  • Hybrid event that transitioned to drizzling stratocumulus conditions by midday

  • An ACE-ENA campaign event having additional ARM assets and a G-1 aircraft mission

  • 5-day air mass back-trajectories originating near southern Manitoba

11

2018-01-26

  • Hybrid event that transitioned to drizzling stratocumulus conditions by midday

  • An ACE-ENA campaign event having additional ARM assets

  • 5-day air mass back-trajectories originating near southern Manitoba

12

2018-02-04

  • This was a multi-day event collected during the ACE-ENA campaign

  • Widespread precipitating stratocumulus conditions under weak flow

  • 5-day back-trajectories that originated near the U.S. Rocky Mountains

13

2018-02-05

  • This was a multi-day event collected during the ACE-ENA campaign

  • Widespread precipitating stratocumulus conditions under weak flow

  • 5-day back-trajectories that originated near the U.S. Rocky Mountains

14

2018-10-27

  • A multi-day event that featured an open to closed cell transition

  • Widespread stratocumulus conditions beginning on October 28th

  • 5-day air mass back-trajectories originated from the U.S. Northeast

15

2018-10-28

  • A multi-day event that featured an open to closed cell transition

  • Widespread stratocumulus conditions beginning on October 28th

  • 5-day air mass back-trajectories originated from the U.S. Northeast

16

2019-03-10

  • A widespread stratocumulus event associated with light southerly winds

  • Select times had more intense drizzle with subcloud precipitation

  • 5-day air mass back-trajectories originated local to the ENA site

17

2022-01-06

  • Widespread and closed cloud event that followed frontal passage

  • Event associated with moderate low-level winds from the northeast

  • 5-day air mass back-trajectories originated from the U.S. west coast

18

2022-04-19

  • Widespread stratocumulus deck associated with low-level easterly winds

  • This cloud deck gradually thinned during the second half of the event

  • 5-day air mass back-trajectories from the U.S. and Canadian west coast

19

2022-04-22

  • Deepening stratocumulus deck that transitioned into a period of open-cell conditions

  • Strong low-level flow from the north that shifted westerly as a front approached

  • Frequent subcloud drizzle was observed

  • 5-day air mass back-trajectories from the U.S. upper Midwest

20

2022-06-22

  • Precipitating stratocumulus deck having embedded cellular behaviors

  • Northeasterly boundary layer winds

  • 5-day air mass back-trajectories that originated near the ENA site