D.C. area forecast: September sizzle holds through Saturday before cold front brings relief; storm chance this evening

Today’s Daily Digit

A somewhat subjective rating of the day’s weather, on a scale of 1 to 10.

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Sultry September start confuses calendar

Express Forecast

Today: Partly sunny, late p.m. storm chance. Highs: 92-97.

Tonight: Evening storm chances. Lows:  66-74.

Tomorrow: Mostly sunny, warm to hot.  Highs: 88-92.

FORECAST IN DETAIL

Temperature Map

Temperatures: Latest D.C. area temperature map. See interactive map on our Weather Wall.

A stubbornly-stalled Bermuda high pressure system pumping tropical air up the East Coast is responsible for our last-minute summer heat.   This feature should stay anchored over the area until a cold front can break it free by this weekend.

While there is significant late-season heat and some humidity for the balance of this week, we are not expecting any records to be broken.  But highs in the upper 80s and 90s don’t feel like autumn yet.  Rain chances are essentially today and then again on Saturday into Sunday with the bigger cold front.

Today (Tuesday): Temperatures take off a bit faster and stronger this morning heading to afternoon peak levels in the low-to-mid 90s.  Moderate to high humidity levels make this the least comfortable day of the week with heat indices in the upper 90s to around 100 (yuck!). Partly sunny skies could occasionally open up to mostly sunny conditions early in the day, but increased clouds build in by mid-to-late afternoon along with a 20-40 percent chance of scattered late day showers and storms (highest odds in western areas).  Light breezes blow from the west and southwest at 5 to 10 mph.   Confidence: Medium-High

storms_01

Tonight:  Scattered evening showers and storms (30-40% chance), with our western suburbs probably seeing the most intense and concentrated activity.  A few of the storms could be strong-severe with isolated damaging wind gusts. Otherwise, it’s muggy evening with some improvement in humidity (lower) later at night thanks to a weak cool front.  Lows drop to the middle to upper 60s in the outer suburbs to the low-to-mid 70s in the city.  Partly cloudy skies overnight with light breezes shifting to come from the northwest after midnight.  Confidence: Medium-High

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…

Tomorrow (Wednesday): The weak cool front from the night before helps to pull down the humidity a notch, but we still have a generally warm to hot air mass in place.  Mostly sunny skies with afternoon highs in the upper 80s to low 90s.  Dew points drop down during the day into the lower to middle 60s (translating to a moderate humidity level).  Winds from the northwest direction at 5 to 10 mph.  Confidence: Medium-High

Tomorrow night: Mostly clear with lows dropping into the lower to middle 60s in the suburbs to near 70 in the city along with very light breezes.  Confidence: Medium-High

A LOOK AHEAD

Thursday and Friday persist the hotter-than-normal theme with mostly sunny skies during the days and mostly clear skies at night.  Highs both days range in the upper 80s to some low 90s with humidity inching back up to moderate-to-high levels again.  Overnight lows from the 60s to the low 70s Thursday and Friday night.  Confidence: Medium-High

The weekend brings some transition as a bigger cold front cuts into the area.  Saturday should still make a run at upper 80s to near 90F high temperatures, but with less duration thanks to increasing afternoon clouds and a healthier chance of late afternoon and evening showers/thunderstorms (60%).  Showers and storms continue Saturday night with lows dropping into the 60s under mostly cloudy skies.  Scattered showers early Sunday before partial clearing during the day.  The big story should be dropping humidity by afternoon with highs only in the lower 80s.  Confidence: Medium

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