Maryland weather: Heat index to get as high as 102 degrees Monday

The National Weather Service is calling for a heat index as high as 102 on Monday to kick off a scorching, humid week in the Baltimore area.

There is also a 20% chance of rain and a chance of thunderstorms starting around 2 p.m. Monday. On Monday night, temperatures are expected to drop into the high 70s, but the heat index, a measure that takes humidity into account, is expected to remain above 90 degrees until at least 10 p.m. The NWS has issued a heat advisory from noon to 8 p.m. for most of the Baltimore-Washington region.

Tuesday is also expected to have a high temperature in the mid-90s with a heat index of 103 and a chance of afternoon showers and thunderstorms. Tuesday night, there is a 30% chance of rain, mostly before 8 p.m., as temperatures drop into the 70s with a heat index above 90 degrees until 10 p.m.

Wednesday, the heat index is expected to reach 106 with a chance of showers and thunderstorms starting in the morning and lasting into the evening. Wednesday night, there is a 50% chance of rain.

The boundary between the air masses in warm and cold fronts is stalled over the Baltimore region with no strong wind or air flow moving it away from the area, according to Chesnea Skeen, a meteorologist for the NWS in Sterling, Virginia. On Monday, airflow from the southeast will bring the warm front through before it stalls again. Then on Thursday, a system strong enough to move the boundary is expected to bring a cold air mass from the west as a cold front.

“We’d have fairly stagnant, continued warm and muggy conditions this week, until later this week with the cold front sweeping through, if it manages to do that,” Skeen said.

Thursday, the heat index is expected to reach 101 in the afternoon with a 50% chance of rain. The chance of rain increases to 60% at night.

Friday is expected to be cooler with highs in the upper 80s and a 70% chance of rain during the day. Friday night also has a 50% chance of rain with the possibility of showers and thunderstorms.

Once the front passes through the area, it will wash out along the coast, and high pressure will build for the weekend, which Skeen said will bring warm air due to the airflow from the south and offshore.