DELMARVA FORECAST
Monday night: *Tornado Watch* Rain and thunderstorms in the evening, a few strong, then lingering showers. Lows in the low 30s. Chance of rain 90 percent.
St. Patrick's Day: Mostly sunny, cold, and breezy. Highs in the mid 40s.
Wednesday: Increasing clouds and cold. Highs in the low 40s.
Thursday: Partly cloudy. Highs in the low 50s.
Friday: Mostly sunny. Highs around 60°F.
Saturday: Partly cloudy. A few showers. Highs in the low 60s. Chance of rain 40 percent.
Sunday: Partly cloudy. Highs around 60°F.
FORECAST DISCUSSION
Normal high: 55°F. Normal low: 35°F.
*Tornado Watch until 7 p.m. Monday*
A strong low pressure system and associated cold front has been bringing severe weather to much of the eastern half of the United States, and that storm system is bearing down on Delmarva Monday evening. Nearly all of Delmarva is under a Level 3 threat of severe weather, with eastern Sussex, Worcester, and eastern Accomack Counties under a Level 2 threat.
Ahead of the front gusty south winds have pushed temperatures well into the 60s, with dewpoints in the low 60s. In this warm and humid environment, thunderstorm cells are expected to develop ahead of the front Monday afternoon and evening. While I think a lot of these storms will lose a good deal of their strength when they cross the cold waters of the Chesapeake Bay, they could still pack a punch, especially if they redevelop over Delmarva, and especially over the Maryland Midshore, where the bay is narrower and will have less of an effect on any thunderstorms.
Damaging wind gusts in excess of 60 mph will be the main threat with Monday evening's thunderstorms. These wind gusts could bring down tree limbs (many are weakened after winter weather a few weeks ago) which could cause isolated power outages.
There is also a threat for tornadoes to spin-up in any thunderstorms. Dynamics are good enough that any tornado could become strong, EF-2 or stronger.
Hail, downpours, and lightning, are lesser, but still possible threats.
The tornado and thunderstorm threat will be over by early to mid evening Monday, with showers lingering to about midnight. Skies will then gradually clear into Tuesday morning.
For Saint Patrick's Day, the sun will make a return, but it will be cold and blustery. Highs only reach the mid 40s, and a gusty west wind will make it feel like the 30s.
The rest of the week will be mainly quiet, with temperatures returning to the 60s by Friday.
Our next chance for rain will possibly be on Saturday.
In the long range, temperatures are expected to average below normal, and precipitation below normal for March 23 - March 29.