The SI Weather
25Jul/14Fri

7:00 AM The weather becomes unsettled this weekend and there can be strong thunderstorms

6-Day Forecast

Today

Mostly sunny, nice, highs in the low-to-mid 80’s
(normal high at DCA is 88 degrees)

Tonight

Mostly clear, comfortable, lows by morning near 65 degrees

Saturday

Mostly sunny, warmer, cannot rule out a late day shower or thunderstorm, upper 80’s

Saturday Night

Mostly cloudy, mild, muggy, chance for showers and thunderstorms, near 70

Sunday

Mostly cloudy, warm, humid, occasional showers and thunderstorms, some of the storms can be quite strong, mid-to-upper 80’s

Monday

Partly sunny, warm, chance for additional showers and thunderstorms, mid-to-upper 80’s

Tuesday

Mostly sunny, quite cool for this time of year, upper 70’s

Wednesday

Mostly sunny, still very pleasant, near 80

Discussion

High pressure will provide a nice end to the work week, but the weather becomes unsettled this weekend and there is a good chance for occasional showers and thunderstorms from Saturday night into Monday and some of the storms can be quite strong with torrential downpours, damaging winds and possible hail. Low pressure will move across the Upper Midwest on Saturday and into the Mid-Atlantic region by late Saturday night before pushing to our north on Sunday. A cold front will then approach on Monday as it moves west-to-east and this will continue the threat for occasional showers and thunderstorms as we begin the new work week. Cooler air anchored by strong Canadian high pressure and well below normal for this time of year will arrive by Tuesday and we’ll stay very comfortable into mid-week.

Video

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24Jul/14Thu

7:00 AM | Yesterday’s heat and humidity being replaced by another refreshing air mass for this time of year

6-Day Forecast

Today

Mostly cloudy, not as warm, still the chance for a couple of scattered showers, lowering humidity will become noticeable later today, highs in the low 80’s

Tonight

Becoming partly cloudy, turning cooler late, lows by morning in the lower 60’s

Friday

Mostly sunny, comfortable, low-to-mid 80’s

Friday Night

Mostly clear, cool, low-to-mid 60’s

Saturday

Partly sunny, warmer, cannot rule out a shower or thunderstorm late in the day or at night, upper 80’s

Sunday

Mostly cloudy, quite warm, more humid, showers and thunderstorms likely, upper 80’s

Monday

Partly sunny, not as warm, humid, chance for showers and thunderstorms, mid 80’s

Tuesday

Partly sunny, a bit cooler, near 80

Discussion

A cold front arrived in the region last night with scattered showers and thunderstorms and it will grudgingly push off the east coast today. As a result, clouds will linger for much of today and a scattered shower is still possible, but less humid air will move in by tonight and conditions will be quite pleasant overnight and on Friday. The weekend will gradually become more unsettled with an isolated shower or thunderstorm late Saturday and then more numerous showers and thunderstorms are likely on Sunday. Cooler weather returns to the region by Tuesday and Wednesday of next week.

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23Jul/14Wed

7:00 AM | Strong storms early tonight as cold front arrives

6-Day Forecast

Today

Partly-to-mostly sunny, hot, humid, chance for showers and thunderstorms at the end of the day, highs in the low 90’s

Tonight

Showers and thunderstorms likely, some of the storms can be strong with torrential downpours, frequent lightning and possible hail, lows in the lower 70’s

Thursday

Mostly cloudy, not as warm, still the chance for showers and thunderstorms, low 80’s

Thursday Night

Mostly cloudy early with a lingering shower possible, some clearing and turning cooler late, near 60

Friday

Mostly sunny, comfortably warm, mid 80’s

Saturday

Partly sunny, warm, mid-to-upper 80’s

Sunday

Partly sunny, warm, more humid, chance for showers and thunderstorms, upper 80’s

Monday

Partly sunny, warm, chance for showers and thunderstorms, mid 80’s

Discussion

A cold front will arrive tonight and it should be accompanied by scattered showers and thunderstorms and some of the storms can be on the strong side. The best chance for showers and thunderstorms will be in the period between 4pm and midnight. The threat for showers and thunderstorms will linger for awhile on Thursday, but humidity will lower noticeably later in the day. High pressure will fill in behind the front on Friday and Saturday with comfortably warm conditions, but then the weather turns unsettled on Sunday with the threat for more showers and thunderstorms. The unsettled weather will continue early next week as a deep upper level trough sets up over the Great Lakes region.

Video

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22Jul/14Tue

2:45 PM | Another chilly air mass for this time of year coming next week

Euro_500mb_anomaly
[Euro 500 mb height anomaly map for next Wednesday; courtesy Weather Bell Analytics at weatherbell.com]

Discussion

The same overall weather pattern that produced a colder-than-normal winter in much of the eastern half of the nation and an impressive cool shot last week will produce another cool shot during the first half of next week in the same general area. Once again, it appears that the pattern is unfolding to allow for the development of a significant trough in the upper atmosphere early next week in the eastern part of the nation and it will be centered on the Upper Midwest. This will produce below normal temperatures for several days in this part of the country with the biggest departure from normal once again focused on the Upper Midwest. Yesterday’s European computer forecast model run for the middle of next week suggests there will be a deep trough of low pressure for this time of year centered over the Upper Midwest – the same type of pattern that we’ve experienced frequently during the past several months (map courtesy Weather Bell analytics at weatherbell.com).

NOAA_records
[Temperature records courtesy NOAA]

Last week’s widespread cool shot was impressive indeed with 2085 cold temperature records set across the nation in the past 7 days as compared with 281 warm temperature records (data courtesy NOAA). It is too early to tell if this next shot of cool air will produce widespread record-breaking chill, but below normal temperatures are very likely (NOAA 6-10 forecast temperature anomaly map shown below for the period July 27th through July 31st).

6-10

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