7:00 AM | Weak cool front works its way through the region...strong cold front arrives at end of week

6-Day Forecast

Today

Becoming partly sunny after early clouds and patchy fog, warm, cannot rule out a shower or two, highs near 80 degrees

Tonight

Mostly cloudy with the chance for showers, turning cooler late, lows in the upper 50’s

Wednesday

Partly sunny, a bit cooler, cannot rule out a shower or two, mid 70’s

Wednesday Night

Mostly cloudy, cool, upper 50’s

Thursday

Partly sunny, cool, low-to-mid 70’s

Friday

Partly sunny, breezy, cool, good chance for late day and nighttime showers. maybe a thunderstorm, mid 70’s

Saturday

Becoming mostly sunny, cool, upper 60’s

Sunday

Mostly sunny, cool, mid 60’s

Discussion

A weak cool front will slide across the region later today giving us the chance for a few showers into the day on Wednesday along with an isolated thunderstorm or two - this will not be a heavy rain event. High pressure will build into the region on Thursday before a strong cold front approaches late in the day on Friday. That next front is likely to generate numerous showers as we close out the work week and maybe a thunderstorm or two. Much cooler air will arrive for the weekend following the passage of the strong cold frontal system.

Video

httpv://youtu.be/HwIg7qba9c0

7:00 AM | High pressure retreats from the area as cold front approaches

6-Day Forecast

Today

Mostly cloudy, a bit cooler, chance for a few showers later today; especially, south and east of the District, highs in the mid-to-upper 70’s

Tonight

Mostly cloudy, mild, chance for a couple of showers, lows near 60 degrees

Tuesday

Partly sunny, warm, cannot rule out a shower, near 80

Tuesday Night

Mostly cloudy, mild, chance for couple of showers, maybe a thunderstorm, near 60

Wednesday

Partly sunny, a bit cooler, maybe a shower or thunderstorm, mid-to-upper 70’s

Thursday

Partly sunny, cooler, low-to-mid 70’s

Friday

Partly sunny, cool, a PM shower or thunderstorm possible, low-to-mid 70's

Saturday

Mostly sunny, cool, near 70

Discussion

High pressure was in control of the weather this weekend, but it will gradually lose its grip on the region as we begin the new work week and a cold front approaches the region. This front will slow down as it approaches the coastline and will keep the threat for showers in the region into mid-week. High pressure rebuilds into the area later this week, but then another cold front approaches the region late Friday with another chance for a shower or thunderstorm.

7:00 AM | Much improvement today and a warm weekend is coming to the region, but late night and early morning fog could be an important issue

6-Day Forecast

Today

Mostly sunny and noticeably warmer with afternoon highs in the upper 70’s

Tonight

Mostly clear early, patchy fog possible late, calm, cool, lows in the mid 50’s

Saturday

Patchy fog possible early; otherwise, partly-to-mostly sunny skies, calm, warm, near 80

Saturday Night

Mostly clear early, low clouds and patchy fog possible late, calm, cool, mid 50’s

Sunday

Patchy fog possible early; otherwise, partly-to-mostly sunny skies, calm, warm, near 80

Monday

Patchy fog possible early; otherwise, partly sunny skies, calm, warm, showers possible at night, near 80

Tuesday

Mostly cloudy, cooler, chance for showers, mid 70’s

Wednesday

Partly sunny, cool, low-to-mid 70’s

Discussion

High pressure will resume control of our weather today as yesterday’s coastal storm pulls away from the east coast. This high pressure will remain rather stationary over the Mid-Atlantic region for the next few days producing generally nice weather around here for the end of September. After a considerable rebound in temperatures this afternoon compared to yesterday’s unusual chill, temperatures on both weekend days should flirt with the 80 degree mark for highs.

There is one fly in the ointment, however, with regard to the weekend weather and that has to do with the possibility of some late night and early morning patchy fog. One reason for the increased threat of fog actually has to do with the stationary high pressure expected this weekend over the Mid-Atlantic region as this will help to generate calm conditions – a favorable factor for nighttime radiational cooling and the formation of fog. Two other favorable factors for fog this weekend include the ever increasing length of the nighttime and the high soil moisture content following yesterday’s soaking rainfall.

Video

httpv://youtu.be/5KyHNKqe6OM

7:00 AM | *Coastal storm gradually pulls away from the area today...much improvement comes on Friday*

6-Day Forecast

Today

Cloudy, chilly and breezy with periods of rain primarily before noon, highs confined to the upper 60’s

Tonight

Mostly cloudy skies with a possible evening shower, breezy and cool, some fog possible late, lows in the low-to-mid 50’s

Friday

Becoming mostly sunny, warmer, mid-to-upper 70’s

Friday Night

Mostly clear early, patchy fog possible late, cool, mid 50’s

Saturday

Patchy fog possible early; otherwise, partly-to-mostly sunny skies, warm, near 80

Sunday

Patchy fog possible early; otherwise, partly-to-mostly sunny skies, warm, near 80

Monday

Partly sunny, comfortably warm, upper 70’s

Tuesday

Mostly cloudy, cooler, maybe a few showers, low-to-mid 70’s

Discussion

Low pressure along the Mid-Atlantic coastline will continue to produce chilly, windy and wet conditions this morning in the DC metro region, but just some light rain or drizzle is likely during the afternoon. The combination of clouds, rain and an ocean flow of air will hold temperatures to unseasonably cool levels during this rain event. This storm is likely to produce 1-2 inches of rain in the region with locally heavier amounts before winding down later today. Temperatures should rebound nicely by tomorrow afternoon with the return of some sunshine and then could flirt with the 80 degree mark for highs on both weekend days. There is the potential for fog this weekend during the late night and early morning hours as a result of the combination of the increasing nighttime hours, high soil moisture content from the heavy rainfall, and high pressure sitting right on top of the region producing little or no wind.

Video

httpv://youtu.be/9noWHc7rqS0

1:30 PM | Developing storm has an impressive feed of moisture surging up the east coast

[Latest satellite image of the developing coastal storm; courtesy NOAA, NASA, Capital Weather Gang]

Discussion

The latest satellite image shows an extensive area of clouds associated with the developing nor’easter from near Cuba to the Mid-Atlantic region (above). The developing coastal storm is tapping into moisture from all the way down to near Cuba and this moisture feed is surging northward thanks to a strong southerly flow of air in the lowest parts of the atmosphere along the southeastern coastline (map below).

[850 millibar moisture transport; courtesy NOAA]

Significant rain has now reached as far north as the southern part of the Delmarva Peninsula (below) and it should reach the DC metro region by the end of the afternoon, into Philly early tonight, and then to the New York City metro region later tonight. The rain and wind will intensify overnight in the I-95 corridor and continue into Thursday and there is the potential for 1-2 inches with locally heavier amounts. The storm’s most important impacts will occur along coastal sections of New Jersey and the Delmarva Peninsula where heavy rain and gale force winds are likely (gusts to 40 mph or so). The storm winds down late tomorrow and there will be much improvement by Friday afternoon with noticeably warmer conditions compared to the expected unseasonably cool day on Thursday.

[Latest NEXRAD radar image; courtesy University of Wisconsin]

7:00 AM | *Significant nor'easter drenches the I-95 corridor tonight and tomorrow*

6-Day Forecast

Today

Lowering and thickening clouds with showers possible by the end of the afternoon, cool, highs in the low 70’s

Tonight

Cloudy with periods of rain, heavy at times, increasing winds, cool, lows in the upper 50’s

Thursday

Cloudy, chilly and breezy with periods of rain, heavy at times early in the day, near 70

Thursday Night

Mostly cloudy, breezy, cool, low-to-mid 50’s

Friday

Mostly sunny, warmer, patchy fog possible late at night, mid-to-upper 70’s

Saturday

Patchy fog possible early; otherwise, partly-to-mostly sunny skies, comfortably warm, near 80

Sunday

Patchy fog possible early; otherwise, partly-to-mostly sunny skies, pleasant, upper 70’s

Monday

Partly sunny, comfortable, upper 70’s

Discussion

Low pressure forming along the east coast will generate a chilly, soaking rain event around here beginning late today and continuing into Thursday. This developing coastal storm could produce one to as much as three inches of rain from the I-95 corridor between DC and New York City and points east to the coastline before pulling away from the region on Friday. Mid-Atlantic coastal sections will be most affected by this nor'easter tonight and Thursday with heavy rainfall and gale force winds generally out of the east-to-northeast. The combination of clouds, rain and an ocean flow of air will hold temperatures primarily in the 60’s on Thursday, but then temperatures should rebound nicely Friday afternoon with the return of some sunshine.

Looking ahead, high temperatures will likely flirt with the 80 degree mark on both weekend days, but fog could become an important factor during the late night and early morning hours. The combination of the increasing nighttime hours, high soil moisture content, and high pressure sitting on top of the region is a recipe for some serious fog to form this weekend in the Mid-Atlantic region.

Video

httpv://youtu.be/ClEhW1ncdoE

3:00 PM | *All systems are go for a significant nor'easter to impact the I-95 corridor between late Wednesday and early Friday*

Discussion

Low pressure will consolidate along the east coast on Wednesday and it will ride right up the coastline producing significant rainfall on the order of 1-3 inches in the DC-Boston corridor from late Wednesday into early Friday. The combination of the intensifying low pressure system and departing strong high pressure to the north will generate a stiff ocean wind (gale force at coast) during the storm along with rainy and chilly conditions. Temperatures on Thursday will likely be confined to the 60’s given the combination of clouds, rain and the persistent ocean flow of air. The low pressure system will pull away from the coastline early Friday and temperatures should rebound rather nicely Friday afternoon and then flirt with the 80 degree mark on both weekend days in much of the I-95 corridor.

7:00 AM | *Significant rain event likely late Wednesday night and Thursday as low pressure rides up the coastline*

6-Day Forecast

Today

Mostly sunny, cool, highs in the low 70’s

Tonight

Mostly clear, cool, lows in the low-to-mid 50’s

Wednesday

Sunshine followed by increasing clouds, cool, low 70’s

Wednesday Night

Becoming mostly cloudy with rain likely late, cool, mid-to-upper 50’s

Thursday

Cloudy, windy and chilly with periods of rain likely, near 70

Friday

Mostly sunny, warmer, mid 70’s

Saturday

Mostly sunny, comfortably warm, near 80

Sunday

Mostly sunny, pleasant, upper 70’s

Discussion

Temperatures this morning are at some of the coolest levels so far this season in many northern and western suburban locations ranging from the mid-to-upper 40's along with clear skies. High pressure will ensure another cool and dry day around here with plenty of sunshine and that same weather pattern will continue into Wednesday. Low pressure will form along the east coast by tomorrow afternoon, however, and this system will quite likely generate a significant rain event for the I-95 corridor from DC-to-Philly-to-NYC late Wednesday night and Thursday. Once that low pushes away from the coast on Friday, temperatures should rebound quite nicely reaching well up into the 70's on Friday afternoon and then to near 80 degrees on Saturday.

Video

httpv://youtu.be/vipLt1MZk8Q

7:00 AM | Yet another refreshing air mass has moved into the region

6-Day Forecast

Today

Mostly sunny, quite breezy, much cooler, highs in the low 70’s

Tonight

Mostly clear, quite cool, lows in the upper 40’s

Tuesday

Mostly sunny, cool, near 70

Tuesday Night

Mostly clear, cool, low 50’s

Wednesday

Mostly sunny, cool, low 70’s

Thursday

Partly sunny, cool, low 70’s

Friday

Mostly sunny, pleasant, mid 70’s

Saturday

Mostly sunny, pleasantly warm, upper 70’s

Discussion

A cool front passed through the region last night and it brought a quick halt to the warmup that we experienced over the weekend. Much cooler air has moved into the Mid-Atlantic and temperatures will remain below normal right through mid-week with high pressure in control. Temperatures late tonight/early tomorrow should drop to some of the coolest levels seen so far - mid-to-upper 40's in outlying areas.

Video

http://youtu.be/J-4pCvj7g8s

7:00 AM | Weekend warmup peaks on Sunday, but will be short-lived...another cool air mass arrives early next week

6-Day Forecast

Today

Mainly sunny skies, cool, highs in the lower 70’s

Tonight

Becoming mostly cloudy, not as cool, maybe a touch of drizzle late, lows in the upper 50’s

Saturday

Clouds and perhaps a touch of drizzle early then becoming partly sunny and warmer, near 80

Saturday Night

Partly cloudy, mild, low 60’s

Sunday

Partly sunny, warm, showers and thunderstorms possible late in the day and at night, low 80’s

Monday

Mostly sunny, cooler, low 70’s

Tuesday

Mostly sunny, quite cool, near 70

Wednesday

Mostly sunny, quite cool, near 70

Discussion

Strong high pressure centered over New England this morning will shift off the New England coastline by tomorrow and this movement will generate an increasing southwesterly flow of air in the Mid-Atlantic region during the weekend along with increasingly warm conditions. Temperatures today will hold in the low 70's for highs, but will increase noticeably tomorrow afternoon and then likely peak on Sunday afternoon in the low 80's. The weekend warmup will be short-lived, however, as another cool front will generate showers and thunderstorms late Sunday and then usher in cooler air for the early and middle parts of next week.

Video

httpv://youtu.be/UJFCfEtue-0