3:15 PM | Perseid meteor shower peaks tonight, but viewing conditions are iffy in the Mid-Atlantic

Discussion

The annual Perseid meteor shower peaks tonight, but sky conditions are iffy in the Mid-Atlantic region. The best time to look for the meteors is between around 11pm and 5am and there is a probably a 50/50 chance for favorable viewing conditions.

The Perseid meteor shower comes every August as the Earth passes through a cloud of dust that comes from Comet Swift-Tuttle as it approaches the sun. Earth's gravity pulls in some of the chunks of debris — small rocks comprised of iron-nickel, stone, other minerals or a combination of these — which turn into bright balls of hot gas when entering Earth's atmosphere. As darkness falls, the meteors appear to come from the constellation Perseus, hence the name; although late in the evening, the meteors originate higher in the sky than the constellation.

Perseid meteoroids hit our atmosphere at ~132,000 mph to produce the annual light show and this particular meteor shower is usually rich in “fireballs” because of the size of the parent comet. Comet Swift-Tuttle has a huge nucleus – about 26 kilometers in diameter whereas most other comets are much smaller with nuclei only a few kilometers across. As a result, Comet Swift-Tuttle produces a large number of meteoroids, many of which are large enough to produce fireballs. In fact, the Perseid meteor shower is considered the “fireball champion” of all of the annual meteor showers. Typically, the meteors are only the size of pebbles, some as small as a grain of sand. This is a good year for viewing with respect to the moon as there will be little interference from the currently waxing crescent moon. Jupiter, Venus and the crescent moon will align in the eastern sky just before sunrise, but whether sky conditions will permit a view of this is up in the air.

7:00 AM | Seasonal conditions continue along coastal locations

6-Day Forecast

Today

Patchy fog early then becoming partly sunny, breezy, seasonably cool, highs in the low 70’s along coastal locations

Tonight

Mostly cloudy, breezy, mild, some fog possible late, lows in the low-to-mid 60’s

Tuesday

Patchy fog early then becoming mostly sunny, seasonably cool, low 70’s

Tuesday Night

Mostly cloudy, mild, patchy fog late, mid 60’s

Wednesday

Patchy fog early then becoming partly sunny, seasonably cool, low 70’s

Thursday

Patchy fog early then becoming partly sunny, seasonably cool, low 70’s

Friday

Patchy fog early then becoming partly sunny, seasonably cool, low 70’s

Saturday

Patchy fog early then becoming partly sunny, seasonably cool, low 70’s

Discussion

Building high pressure will produce dry conditions around here for much of the week. The normal high for this time of year at LAX is about 75 degrees and coastal locations should climb pretty close to seasonal levels over the next several days.

Video

httpv://youtu.be/p-ZSpAius4E

7:00 AM | Still comfortable temperatures with scattered showers and thunderstorms

6-Day Forecast

Today

Partly sunny, comfortably warm, scattered showers and thunderstorms, highs in the low-to-mid 80’s

Tonight

Mostly cloudy, cool, chance for evening showers and thunderstorms, lows by morning in the upper 50’s

Tuesday

Partly sunny, cooler, scattered showers and thunderstorms, upper 70's

Tuesday Night

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

Wednesday

Partly sunny, cool, chance for showers and thunderstorms, upper 70's

Thursday

Partly sunny, warmer, slight chance for showers and thunderstorms, low-to-mid 80’s

Friday

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

Saturday

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

Discussion

The general pattern featuring scattered showers and thunderstorms; especially, during the afternoon and evening hours, will continue for the next couple of days. An upper level disturbance will enhance the storm activity later today and some of the storms that form can be on the strong side. It'll turn somewhat cooler on Tuesday and Wednesday with the continued shower/thunderstorm threat, but drier and warmer weather is likely later this week as high pressure builds in overhead.

Video

httpv://youtu.be/p-ZSpAius4E

11:15 AM | No "gloom and doom" around here - wildfires, drought, heat waves, tornadoes all down this year across the US and the on-going break from major hurricane strikes has been historic

Discussion

Whether you’re talking about wildfires, drought, heat waves, tornadoes or hurricanes, weather-related disasters in the US are all down compared to recent years and if you have been in the “doom and gloom” forecast business then you must be quite disappointed.

To begin with, the actual number of wildfires across the US using year-to-date statistical comparisons (below) is currently the lowest it has been in the past ten years and the acreage involved is at the second lowest level in that same time period. The number of wildfires typically corresponds pretty well with heat and drought conditions and indeed the percentage of the contiguous US that is currently experiencing abnormally dry or drought conditions is around 57% which is considerably lower than the 79% recorded at this same time one year ago. Also, the number of nationwide high temperature records for this year is far below last year with 17,486 high max or high min temperature records as compared with nearly 50,000 at this same point one year ago.

In addition, barring a very surprising and abnormally active fall season, the number of tornado reports this year is on a pace quite likely well below those reported in all years going back to 2000 (below). Finally, as far as hurricanes are concerned, even though there has not been a hurricane yet this season, it is way too early to make any conclusions about this year’s Atlantic tropical season as the climatologically active time period is really just beginning (mid-August through September). It is noteworthy, however, to point out there has that there has not been a major hurricane strike (ie category 3, 4 or 5) in the US since October 2005 when Hurricane Wilma struck during that particular very active tropical season. In fact, this is the longest stretch without a major hurricane strike in the US since the Civil War - let’s hope that trend continues. By the way, just as a point of comparison, in 1954 the US was hit by 3 major hurricanes in less than 10 weeks.

Wildfires 2013 (1/1/13 - 8/9/13) Fires: 29,421 Acres: 2,587,916 2012 (1/1/12 - 8/9/12) Fires: 39,097 Acres: 4,938,791 2011 (1/1/11 - 8/9/11) Fires: 47,187 Acres: 6,320,510 2010 (1/1/10 - 8/9/10) Fires: 41,447 Acres: 2,153,282 2009 (1/1/09 - 8/9/09) Fires: 59,822 Acres: 4,928,612 2008 (1/1/08 - 8/9/08) Fires: 56,751 Acres: 3,985,545 2007 (1/1/07 - 8/9/07) Fires: 58,866 Acres: 5,460,184 2006 (1/1/06 - 8/9/06) Fires: 73,661 Acres: 5,954,944 2005 (1/1/05 - 8/9/05) Fires: 40,661 Acres: 5,248,877 2004 (1/1/03 - 8/9/04) Fires: 50,555 Acres: 5,606,786 Source: National Interagency Fire Center, http://www.nifc.gov/fireInfo/nfn.htm

Tornadoes 2013 712 (through Aug 9th) 2012 1119 2011 1894 2010 1543 2009 1305 2008 1685 2007 1102 2006 1117 2005 1262 2004 1820 2003 1374 2002 938 2001 1219 2000 1072 Source: NOAA, http://www.spc.noaa.gov/climo/online/monthly/newm.html

Drought information source: http://droughtmonitor.unl.edu/DM_tables.htm?conus

Heat wave information source: http://www.ncdc.noaa.gov/extremes/records/

7:00 AM | Onshore flow continues with an overcast start to the day followed by PM clearing

6-Day Forecast

Today

Patchy fog early then becoming partly sunny, breezy, cool, highs near 70 degrees along coastal locations

Tonight

Mostly cloudy, breezy, mild, some fog possible late, lows in the low 60’s

Saturday

Patchy fog early then becoming partly sunny, cool, near 70

Saturday Night

Mostly cloudy, mild, patchy fog late, low 60’s

Sunday

Patchy fog early then becoming partly sunny, cool, near 70

Monday

Patchy fog early then becoming partly sunny, seasonably cool, low 70's

Tuesday

Patchy fog early then becoming partly sunny, seasonably cool, low 70's

Wednesday

Patchy fog early then becoming partly sunny, seasonably cool, low 70's

Discussion

A persistent low pressure system to our north will continue to bring low clouds and fog to coastal regions during the late nights and early morning hours followed by PM clearing skies. Temperatures will stay at cooler-than-normal levels along coastal regions with highs doing no better than 70 degrees through the weekend, but there is likely to be a slight warmup early next week.

Video

httpv://youtu.be/7BZgwnHw9U0

7:00 AM | Still below normal temperatures today with highs at or just below 80 degrees

6-Day Forecast

Today

Partly sunny, comfortably warm this afternoon after a cool start to the day, scattered showers and thunderstorms, highs in the upper 70’s

Tonight

Mostly cloudy, cool late, chance for evening showers and thunderstorms, lows by morning in the mid 50’s

Saturday

Partly sunny, warm, scattered showers and thunderstorms, low 80’s

Saturday Night

Partly cloudy, cool, slight chance for showers and thunderstorms, upper 50’s

Sunday

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

Monday

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

Tuesday

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

Wednesday

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

Discussion

An upper level ridge will build over the state today and produce a westerly flow in the upper atmosphere. In the lower levels of the atmosphere, however, winds will generally be in a southeasterly direction and this will add enough moisture to the environment to allow for the possibility of scattered showers and thunderstorms. The weekend will see less of a chance for rain as the ridge expands overhead.

Video

httpv://youtu.be/7BZgwnHw9U0

1:10 PM | The sun remains rather quiet despite approaching the solar maximum and a flip in its magnetic field

Discussion

The sun is the main driver of all weather and climate on Earth and it remains rather quiet in recent days despite the fact that something big is about to happen as we approach the expected solar maximum for this particular solar cycle. Indeed, according to recent measurements from NASA observatories, the sun’s vast magnetic field is about to flip with the sun’s north pole going from negative to positive and the south pole reversing from positive to negative. It looks like we may be about 3 or 4 months away from a complete magnetic field reversal on the sun which happens regularly at the peak of each solar cycle approximately every 11 years or so. The complete reversal will mark the midpoint of solar cycle 24 with half of the solar max period behind us and half yet to come. The typical process involved on the sun during this transition period first involves a weakening of the sun’s polar magnetic fields, then they go to zero, and then they emerge again with the opposite polarity – all a regular part of the solar cycle. While these transitions can stir up stormy space weather around our planet and cosmic rays can be affected, there is typically not a serious impact here on Earth from these solar magnetic field reversals.

Solar cycle 24 is now well over four years old and it continues to “underwhelm” and be on a pace that could make it the smallest sunspot cycle since Cycle 14 which peaked in February 1906. There is a growing feeling that, based on the recent inactivity, the peak may have already happened during the latter part of 2011. Another theory suggests that there may be a “double-peak” solar maximum for this cycle which would mean there could be a sharp spike in sunspot activity still to come later this year or in 2014.

Solar cycle 24 began after an unusually deep solar minimum that lasted from 2007 to 2009 which included more spotless days on the sun compared to any minimum in almost a century. While a weaker solar cycle does not rule out the threat for strong solar storms, it does suggest that they will occur less often than during the stronger and more active cycles. The increasingly likely outcome for a weak solar cycle continues the recent downward trend in sunspot cycle strength that began over twenty years ago with solar cycle 22. In addition, there are some solar scientists who are already predicting that the next cycle, 25, will be even weaker than this current one. According to some research studies, weak solar cycles with extended lengths may actually have a downward effect on global temperatures in the medium and longer range. Weak solar cycles tend to last longer than the strong ones. There have been historical periods with minimal sunspot activity that lasted for several decades such as from the mid 1600’s to the early 1700’s when the so-called “Maunder Minimum” occurred and this period was quite cold globally.

In addition to the cycles on the sun, of critical importance to weather and climate on Earth are our oceanic cycles. An interesting aspect to this apparent weakening solar cycle trend is that it looks like it will coincide with a cold phase of the northern Pacific – the largest ocean on Earth. The sea surface temperature anomalies in the northern Pacific Ocean are tracked through an index called the Pacific Decadal Oscillation (PDO). The PDO slipped into a negative (cold) phase a few years ago and these oceanic cycles can last for two or three decades. Global temperature anomalies have indeed trended downward over the past few years seemingly right after the PDO flipped to a negative (cold) phase. We’ll continue to periodically report on the latest solar activity here at “thesiweather.com” as well as the all-important oceanic cycles to monitor any important changes that may unfold.

Video

httpv://youtu.be/0Ao4GtkfbiY

7:00 AM | Much of the same with afternoon high temperatures near 70 degrees along coastal regions

6-Day Forecast

Today

Patchy fog early then becoming mostly sunny, breezy, cool, highs near 70 degrees along coastal locations

Tonight

Mostly cloudy, breezy, mild, some fog possible late, lows in the low 60’s

Friday

Patchy fog early then becoming partly sunny, cool, near 70

Friday Night

Mostly cloudy, mild, patchy fog late, low 60’s

Saturday

Patchy fog early then becoming partly sunny, cool, near 70

Sunday

Patchy fog early then becoming mostly sunny, cool, near 70

Monday

Patchy fog early then becoming mostly sunny, cool, near 70

Tuesday

Patchy fog early then becoming mostly sunny, cool, near 70

Discussion

A persistent low pressure system will deepen and continue to continue to bring low clouds and fog to coastal regions during the late nights and early mornings. The pattern for afternoon high temperatures to reach near 70 degrees will continue along coastal section right into early next week.

Video

httpv://youtu.be/0YrU_0IcPmQ

7:00 AM | On the cool side today with fog early and then the chance for more showers and storms

6-Day Forecast

Today

Patchy fog this morning; otherwise, mostly cloudy skies, comfortable temperatures, scattered showers and thunderstorms, highs in the upper 70’s

Tonight

Mostly cloudy, cool, chance for evening showers and thunderstorms, lows by morning in the mid 50’s

Friday

Partly sunny, warm, scattered showers and thunderstorms, near 80

Friday Night

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

Saturday

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

Sunday

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

Monday

Mostly sunny, warm, slight chance for showers and thunderstorms, low-to-mid 80’s

Tuesday

Mostly sunny, warm, slight chance for showers and thunderstorms, low-to-mid 80’s

Discussion

Another upper level trough will bring us a surge of cooler air for today and confine high temperatures to the upper 70’s which is well below the current normal high at Denver of 89 degrees. We’ll climb somewhat in temperatures this weekend as the flow aloft will become more southwesterly and this will also allow for some subtropical moisture to return to the region. As a result, there will likely be isolated showers and thunderstorms during afternoon and evening hours this weekend and early next week.

Video

httpv://youtu.be/0YrU_0IcPmQ

1:00 PM | Perseid meteor shower has begun and will peak Monday night/Tuesday morning

Discussion

The annual Perseid meteor shower has already begun and it will peak next Monday night and early Tuesday morning (8/12-13). The Perseid meteor shower comes every August as the Earth passes through a cloud of dust that comes from Comet Swift-Tuttle as it approaches the sun. Earth's gravity pulls in some of the chunks of debris — small rocks comprised of iron-nickel, stone, other minerals or a combination of these — which turn into bright balls of hot gas when entering Earth's atmosphere. As darkness falls, the meteors appear to come from the constellation Perseus, hence the name; although late in the evening, the meteors originate higher in the sky than the constellation.

Perseid meteoroids hit our atmosphere at ~132,000 mph to produce the annual light show and this particular meteor shower is usually rich in “fireballs” because of the size of the parent comet. Comet Swift-Tuttle has a huge nucleus – about 26 kilometers in diameter whereas most other comets are much smaller with nuclei only a few kilometers across. As a result, Comet Swift-Tuttle produces a large number of meteoroids, many of which are large enough to produce fireballs. In fact, the Perseid meteor shower is considered the “fireball champion” of all of the annual meteor showers.

The best time to look during the peak is between the hours of 11pm (Monday night) and 5am (Tuesday morning) far away from city lights. In dark locations with clear skies, the Perseid meteor rate could top 100 per hour. Typically, the meteors are only the size of pebbles, some as small as a grain of sand. This should be a good year for viewing, weather permitting, as there will be little interference from a waxing crescent moon. This year’s display is extra special because Jupiter, Venus and the crescent moon align just as the Perseids peak. The alignment occurs in the eastern sky before sunrise on the mornings of the highest meteor activity.