Commissioning Week Weather Forecast (21 MAY 2018)

  POSTED ON: Monday, May 21, 2018 2:18 PM by Meteorologist A..R. Davies

Executive Summary:

• Monday: Mostly sunny and pleasant. Increasing clouds with a slight chance for scattered showers/storms overnight (25% chance). East wind around 5 mph. High near: 77 ^oF.
• Tuesday: A mix of clouds and sun with scattered showers/storms during the morning/early afternoon (30% chance). Showers and thunderstorms likely in the afternoon/evening (70% chance). Isolated thunderstorms could be strong with heavy downpours and small hail. South wind 8-13 mph. High: 74-78 ^oF.
• Wednesday: Partly sunny and seasonable with isolated showers and thunderstorms in the morning/early afternoon (20% chance). Low forecast confidence. Northwest wind 5-10 mph. High: 76-80 ^oF.
• Thursday: Sunny and pleasant. North wind 5-10 mph. High: 76-80 ^oF.
• Friday: Partly sunny and mild. Southwest wind 8-13 mph. High: 78-82 ^oF.

Forecast Discussion:

After a week of tumultuous weather, Monday has been a picturesque spring day in Annapolis! On Tuesday a warm front will lift north across the region. Behind the front, southerly flow will usher in a more humid and unstable air mass. Expect a mix of clouds and sun during the day with scattered passing showers. However, as indicated by the NAM/Wrf model simulated radar below, a more pronounced line of showers and thunderstorms is likely during the late afternoon/evening as the day heats up. Isolated storms could be strong with heavy downpours or small hail. The National Weather Service has indicated only a marginal risk of severe weather on Tuesday. Scattered showers/thunderstorms are possible Tuesday night and early Wednesday morning. 

Wednesday will be the most challenging forecasting day this week as a slow moving front gradually will pass. At the moment, most data suggest that the front (and most of the associated showers/storms) will be to our south by 1200 EDT, as shown by the GFS/American model below. However, if the front is slower to pass, some isolated showers and rumbles of thunder are possible in the early afternoon. The good news is that the front will be weak with partly sunny skies and only isolated showers and thunderstorms (regardless of the timing).

High pressure will build overhead on Thursday before sliding just offshore on Friday (see GFS/American model below). Thursday will be sunny and comfortable behind a northwest wind. Partly sunny and seasonably warm temperatures will likely prevail on Friday. However, as the High shifts offshore, southerly flow will develop which may increase the humidity a bit on Friday for Graduation.

Category: General Interest