2:30 PM | Sunspot region unleashes another solar flare (M-class) early Friday; possible northern lights tonight from X-flare that occurred earlier this week

Discussion

The active sunspot region called AR1748 unleashed an M-class solar flare at 0858 UT on Friday, May 17th. While this is not the strongest flare that we’ve seen from AR1748, it actually may be the most geoeffective as this sunspot is now facing the Earth more directly than before, and the explosion might have hurled a coronal mass ejection (CME) towards the Earth.

Another CME that was sent into space earlier this week by an X1-flare from the same sunspot region might deliver a glancing blow to the Earth’s magnetic field later tonight. NOAA forecasters estimate a 40% chance of polar geomagnetic storms when the cloud arrives. High-latitude sky watchers should be on alert for northern lights later tonight.

Stay tuned.

7:00 AM | Will be dry and pleasant today, but the threat for showers and thunderstorms returns this weekend as front hangs around the region

6-Day Forecast

Today

Mostly sunny, pleasant, highs near 80 degrees

Tonight

Partly cloudy, mild, lows in the mid-to-upper 50’s

Saturday

Mostly cloudy, cooler, chance for showers and thunderstorms, low 70’s

Saturday Night

Mostly cloudy, mild, chance for showers and thunderstorms, upper 50’s

Sunday

Mostly cloudy, cool, showers likely, maybe a thunderstorm, near 70

Monday

Mostly cloudy, not quite as cool, showers and thunderstorms possible, mid 70’s

Tuesday

Mostly cloudy, warmer, more humid, chance for showers and thunderstorms, low-to-mid 80’s

Wednesday

Partly sunny, warm, humid, showers and thunderstorms possible, mid 80’s

Discussion

A frontal system has stalled just south of here at the same time high pressure is building into New England. While today should stay on the dry side, the threat for showers and thunderstorms will return on Saturday and continue right into early next week as the frontal system hangs around the region. The clouds will help to create cooler conditions this weekend with high temperatures on both weekend days not far from 70 degrees which is below normal for this time of year. Winds will become southwesterly by Tuesday and this change will usher in a warm and more humid air mass by the middle of next week.

Video

httpv://youtu.be/zGUFJ-4TiIE

12:25 PM | Active sunspot region has unleashed four X-class solar flares in the past few days; CME could deliver glancing blow to Earth's upper atmosphere tomorrow

Discussion

The active sunspot region called AR1748 has unleashed four X-class solar flares in the past few days and it might not be finished yet as it continues to grow and has a magnetic field that harbors energy for more X-class solar flares according to NASA scientists. (Other solar flare categories include M-class, which are medium strength and C-class which are small and relatively weak). This particular sunspot region has actually produced more X-flares than every other sunspot of the past year combined.

The last of the four solar flares which occurred early yesterday did produce a coronal mass ejection (CME) that may deliver a glancing blow to Earth’s magnetic field on Friday, May 17th. As a result, northern lights are possible across northern latitudes when the CME reaches the Earth’s upper atmosphere on Friday. The threat for more X-flares continues from AR1748 as it now moves into a location that puts the Earth directly in the line of fire. NOAA forecasters put the odds of another X-flare at 60%. The largest X-class solar flare in this particular solar cycle (#24) was an X6.9 that occurred on August 9th, 2011.

Stay tuned.

Video

httpv://youtu.be/l8HO2ELAhrw

7:00 AM | Stalled out frontal system keeps us unsettled with mid-day and afternoon showers likely

6-Day Forecast

Today

Mostly cloudy, warmer, good chance for showers and possibly a couple of thunderstorms during the mid-day and afternoon hours, highs near 80 degrees

Tonight

Partly cloudy, mild, chance for showers and thunderstorms, lows in the upper 50’s

Friday

Partly sunny, warm, a chance for a shower or thunderstorm, near 80 degrees

Friday Night

Mostly cloudy, mild, chance for showers and thunderstorms, mid 50’s

Saturday

Mostly cloudy, cooler, chance for showers and thunderstorms, low 70’s

Sunday

Mostly cloudy, cool, showers and thunderstorms possible, low 70’s

Monday

Mostly cloudy, cool, chance for showers and thunderstorms, low-to-mid 70’s

Tuesday

Mostly cloudy, warmer, showers possible, maybe a thunderstorm, near 80

Discussion

A frontal system passed through the region yesterday and has stalled out near the area at the same time high pressure builds across New England. This stalled out frontal system will keep things unsettled over the next couple of days with the constant threat for showers and thunderstorms although much of the time will be rain-free. One band of showers is dropping southeast from southern Pennsylvania this morning and it is likely to move across the DC region during the mid-day and afternoon hours. It’ll turn slightly cooler over the weekend as the New England high pressure influences the region and the threat for showers and thunderstorms will continue.

Video

httpv://youtu.be/WxFj57FYNnA

7:00 AM | Much milder for the second half of the week, but the threat exists for scattered showers and thunderstorms

6-Day Forecast

Today

Mostly cloudy, chance for a couple of showers and maybe an afternoon thunderstorm, warmer, highs near 80 degrees

Tonight

Mostly cloudy, mild, chance for a shower or thunderstorm, lows in the mid 60’s

Thursday

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

Thursday Night

Partly cloudy, mild, chance for a shower and thunderstorm, upper 50’s

Friday

Partly sunny, warm, chance for a shower and thunderstorm, near 80

Saturday

Mostly cloudy, not as warm, chance for showers and thunderstorms, mid 70's

Sunday

Mostly cloudy, mild, showers and thunderstorms possible, mid 70's

Monday

Mostly cloudy, mild, chance for showers and thunderstorms, mid-to-upper 70’s

Discussion

Milder air will push into the region today, but it'll be accompanied by mostly cloudy skies and the threat for a shower or thunderstorm at just about any time. Weak high pressure takes over for the last couple days of the work week, but a shower or thunderstorm cannot be ruled out either day as temperatures climb to or slightly past the 80 degree mark. A low pressure area will move to the east this weekend and enhance our chances for showers and thunderstorms and bring us slightly cooler conditions.

An update on the sun - there has been a fourth "X-class" solar flare from the very active sunspot region called AR1748 that occurred earlier today. Before the week began, the sun had not unleashed any X-class flares, but now there have been four in just the past few days.

Video

httpv://youtu.be/zKQUZuEUxsE

11:40 AM | *Solar activity surges with strongest flares of the year - all three classified as X-level, the most intense type*

Discussion

Solar activity has surged in the past two days as a large sunspot region officially called AR1748 has actually generated three different solar flares classified by NASA as “X-class” eruptions, the most intense type of flare, and the strongest flares of the year so far. (Other solar flare categories include M-class, which are medium strength and C-class which are small and relatively weak). Specifically, in just the past two days, there have been three solar flares with increasing strength classified as X1.7, X2.8 and X3.2, and they signal a significant increase in solar activity. The largest X-class solar flare in this particular solar cycle (#24) was an X6.9 that occurred on August 9th, 2011.

Thus far, this recent surge in solar activity has occurred while the Earth was not in the direct line of fire, but this particular sunspot region is now rotating into that direction. Additionally, it appears another sunspot region is about to rotate into view from the sun’s eastern limb and there is reason to believe that it is quite an active region as well. All of these flares have produced strong flashes of extreme ultraviolet radiation and the NASA Solar Dynamics Observatory (SDO) has captured video which shows that the explosions produced coronal mass ejections (CMEs) blasting plenty of plasma material into space. These active sunspot regions will continue to be monitored over the next few days here at thesiweather.com. NOAA forecasters estimate a 40% chance of more X-flares during the next 24 hours or so.

Video

httpv://youtu.be/jsvQhBRKPCw

7:00 AM | Another chilly day, but the 80's will return later this week; transition from cold to warm will be accompanied by scattered showers and thunderstorms

6-Day Forecast

Today

A mix of sun and clouds, a bit milder after a chilly start, highs in the mid-to-upper 60’s

Tonight

Mostly cloudy, cool, chance for a shower and thunderstorm, lows in the upper 40’s

Wednesday

Mostly cloudy, milder, chance for showers and thunderstorms late in the day, near 80

Wednesday Night

Mostly cloudy, chance for showers and thunderstorms, mild, low-to-mid 60’s

Thursday

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

Friday

Partly sunny, warm, chance for a shower and thunderstorm, near 80

Saturday

Partly sunny, warm, chance for a shower and thunderstorm, low 80’s

Sunday

Mostly cloudy, breezy, warm, showers and thunderstorms likely, near 80

Discussion

A chilly start to the day and, although the afternoon will be slightly milder than yesterday, temperatures will stay below normal for this time of year as some clouds roll in. Milder air will try to push into the region by tomorrow and the transition from cold to warm will be accompanied by scattered showers and thunderstorms anytime from late tonight through tomorrow night. Once the milder air becomes established in the region, high temperatures are likely to surpass the 80 degree mark later in the week. One final note, cicadas have begun to emerge in northern Virginia in recent days and, as the milder air returns around here, that resurgence of the insects will advance northward.

Video

httpv://youtu.be/O0uVecgW7gU

7:00 AM | Chilly air mass for this time of year, but warmer second half of the week; low temperatures reached late tonight/early Tuesday won't be see again until next autumn

6-Day Forecast

Today

A mix of sun and clouds, chilly, highs near 60 degrees

Tonight

Mostly clear, cold, patchy frost possible in the normally coldest locations, lows in the mid-to-upper 30’s

Tuesday

Mostly sunny, still cool, mid 60’s

Tuesday Night

Mostly cloudy, chilly, mid 40’s

Wednesday

Partly sunny, milder, chance for showers and thunderstorms late in the day or at night, mid-to-upper 70’s

Thursday

Partly sunny, breezy, warm, chance for showers and thunderstorms, low-to-mid 80’s

Friday

Partly sunny, breezy, warm, chance for showers and thunderstorms, near 80

Saturday

Mostly sunny, warm, near 80

Discussion

A strong cold front pushed off the east coast this weekend and that ushered in a chilly Canadian air mass for this time of year. Temperatures today will struggle to reach 60 degrees for highs which is about 15 degrees below normal for mid-May and tonight will feature temperatures dropping into the 30's in northern and western suburban locations and patchy frost is possible in the normally coldest low elevation spots. You may want to protect outdoor plants this evening if they are susceptible to cold. Another cool day on Tuesday will be followed by milder weather at mid-week and high temperatures will climb into the 80's during the second half of the week. It'll very likely turn out that the low temperatures reached late tonight/early Tuesday will not be experienced again around here until next autumn.

Video

httpv://youtu.be/LeWK68xtX8s

1:30 PM | Quiet tornado season continues as a result of the spring chill; now at a 60-year low for the past 12 months

Discussion

With yet another widespread cold air mass headed for the Midwest, Mid-Atlantic and New England later this weekend, it is time to update the positive aspects of this cool spring with regards to tornadoes. Indeed, tornado activity for the 12 months is now the lowest it has been in 60 years (since 1954) and the number of fatalities has dropped significantly since the very active 2011 severe weather season. Through Thursday, there have been three tornado related fatalities compared to two years ago when more than 500 people were killed as a result of tornado activity.

In terms of the number of tornadoes, the year-to-date count is approaching the lowest 10% of all years on record according to NOAA’s Storm Prediction Center in Norman, Oklahoma. Only three tornadoes have formed so far in the month of May which is usually the USA’s most active month, and all three were rated at the weakest classification level (EF-0). According to NOAA, April 2013 ended up with 83 official tornado reports as compared with 206 last year and 758 in 2011. March 2013 ended up with only 18 tornadoes as compared with 154 last year and 75 in 2011.

In terms of the cause of the quiet tornado season, the cold has been so relentless across the Rockies, Plains, South and East during the past couple of months that it has stopped in its tracks one necessary requirement for severe weather and that is the advance northward of very warm and humid air from the Gulf of Mexico. This upcoming cold air outbreak will send many places 15 to 20 degrees below normal for this time of year later this weekend and early next week and it will no doubt inhibit tornado activity during that stretch of weather.

7:00 AM | A taste of summer today with 85 degrees possible then chill returns for Sunday/Monday/Tuesday and there will be showers and thunderstorms in between

6-Day Forecast

Today

Partly sunny, very warm, chance for late afternoon showers and thunderstorms, some of the rain can be heavy at times, highs near 85 degrees

Tonight

Cloudy, mild, showers and thunderstorms likely, some of the rain can be heavy at times, lows in the low 60’s

Saturday

Mostly cloudy, mild, more showers and thunderstorms likely, some of the rain can be heavy at times, mid 70’s

Saturday Night

Mostly cloudy, mild, still the chance for showers and thunderstorms, upper 50’s

Sunday

Partly sunny, breezy, cooler, upper 60’s

Monday

Mostly sunny, breezy, chilly, low 60's

Tuesday

Mostly sunny, still on the cool side, mid-to-upper 60’s

Wednesday

Partly sunny, milder, upper 70’s

Discussion

There will be a taste of summer today as sunshine will help to boost afternoon temperatures to 85 degrees, but the threat for showers and thunderstorms will return by later this afternoon as our unsettled weather pattern continues. The threat for showers and thunderstorms will continue tonight and on Saturday as a strong cold front moves towards the eastern states from the Upper Midwest. While much of the time between this afternoon and tomorrow evening will be rain-free, it can rain at just about any time and any of the rain that falls can be briefly heavy. This strong cold front will sweep off the east coast on Sunday and much cooler air will follow for the Sunday/Monday/Tuesday time period. In fact, temperatures could drop into the 30’s in some of the northern and western suburbs early Monday and Tuesday mornings. Milder air returns to the Mid-Atlantic region by the middle part of next week.

Video

httpv://youtu.be/IxYrCg4PV30