7:00 AM | Coldest air yet this season moves in later this week; Saturday morning will be quite chilly indeed

6-Day Forecast

Today

Partly sunny, windy, cool, highs in the low-to-mid 60’s

Tonight

Becoming cloudy, breezy, cool, chance for showers late, lows in the low 50’s

Thursday

Mostly cloudy, windy, cool, showers possible, mid 50’s

Thursday Night

Becoming partly cloudy, cold, low-to-mid 40’s

Friday

Mostly sunny, quite cool, mid 50’s

Saturday

Mostly sunny, cool, mid 50’s

Sunday

Mostly sunny, cool, near 60

Monday

Mostly sunny, cool, near 60

Discussion

A significant cool down will occur later this week as a strong upper level low pressure trough approaches the region. Showers could accompany the cool down late tonight and Thursday and it could get cold enough for snow in some of the nearby mountains. Temperatures will hold well below normal on Friday and early Saturday morning could very well feature some of the coldest temperatures yet this season.

Video

httpv://youtu.be/x9ILedcyOPA

7:00 AM | Cooler, unsettled weather returns by Thursday

6-Day Forecast

Today

Mostly sunny, pleasant, highs in the mid-to-upper 60's

Tonight

Partly cloudy, cool, lows near 50 degrees

Wednesday

Mostly sunny, windy, cooler, low 60’s

Wednesday Night

Becoming mostly cloudy, cool, showers possible, near 50

Thursday

Mostly cloudy, quite cool, showers possible, mid 50’s

Friday

Partly sunny, quite cool, mid 50’s

Saturday

Mostly sunny, quite cool, mid-to-upper 50’s

Sunday

Mostly sunny, still quite cool, upper 50’s

Discussion

Normal high temperatures for this time of year at the LA International Airport (LAX) is 65 degrees and we have a pretty decent shot at reaching or even surpassing that mark this afternoon with abundant sunshine. As the week progress, temperatures will trend downward as an upper low and its associated strong cold frontal system approach the region. Showers are possible on Wednesday night and Thursday as the cooler air moves into southern California and it looks like it will stay cool right through the weekend.

Video

httpv://youtu.be/Qm-eBKRpHlY

7:00 AM | Unseasonably mild through mid-week; much colder by the end of the week

6-Day Forecast

Today

Mostly sunny, milder, highs in the low 50’s

Tonight

Mostly clear, cold, lows in the upper 20’s

Wednesday

Mainly sunny, unseasonably mild, mid-to-upper 50’s

Wednesday Night

Mostly clear, cold, upper 20’s

Thursday

Mostly sunny, still mild, mid 50’s

Friday

Mostly cloudy, much colder, chance for some snow, low 30’s

Saturday

Mostly cloudy, very cold, low 20’s

Sunday

Mostly sunny, very cold, mid 20’s

Discussion

A thaw will continue today and tomorrow with high temperatures likely to exceed the 50 degree mark which is well above normal for this time of year (normal high is 44 degrees). Much colder air is likely to return by the end of the week and that transition back to reality could be accompanied by some snow to close out the work week. The renewed cold weather will continue in the region this weekend.

Video

httpv://youtu.be/Qm-eBKRpHlY

12:30 PM | Suddenly, a big jump in sunspots

Discussion

2013 is now well underway and this is the year that the current solar cycle 24 is supposed to reach a solar maximum. This cycle, which has been relatively weak so far, began in the 2008/2009 time frame after a long minimum period with virtually no sunspot activity that followed solar cycle 23. While the last part of 2012 was quite quiet on the sun in terms of solar flares and overall sunspot activity, the New Year has suddenly brought about a rapid increase in sunspot numbers suggesting the quiet may not last much longer. In fact, over the weekend a plethora of new sunspot groups appeared on the sun and each one of these has the potential for eruptions. These newly visible sunspot regions will rotate over the next several days to the zone on the sun directly facing the Earth and we’ll continue to monitor the situation for any possible eruptions that could have an effect on the Earth’s atmosphere.

Video

httpv://youtu.be/_N2R20X7jek

7:00 AM | Cool and sunny to start the week

6-Day Forecast

Today

Mostly sunny, breezy, cool, highs in the low 60's

Tonight

Partly cloudy, windy, cold, lows in the mid 40’s

Tuesday

Mostly sunny, cool, low-to-mid 60’s

Tuesday Night

Mostly clear, chilly, near 50

Wednesday

Partly sunny, windy, cool, low 60’s

Thursday

Partly sunny, cooler, chance for showers, mid-to-upper 50’s

Friday

Mostly sunny, cool, mid-to-upper 50’s

Saturday

Mostly sunny, cool, upper 50's

Discussion

Showers have cleared the area and our weather will stay dry, but cool into mid-week controlled by a high pressure ridge. The ridge moves away on Wednesday and a low pressure trough will drop into California by Thursday increasing the chance for showers.

Video

httpv://youtu.be/FI7ahScZxTU

7:00 AM | A run towards 50 degrees today; stays warm until the end of the week

6-Day Forecast

Today

Mostly sunny, milder, highs near 50 degrees

Tonight

Mostly clear, cold, lows in the mid 20’s

Tuesday

Mainly sunny, mild, low 50's

Tuesday Night

Mostly clear, cold, low 20’s

Wednesday

Mostly sunny, mild, mid-to-upper 50’s

Thursday

Partly sunny, still mild, low-to-mid 50's

Friday

Mostly sunny, much colder, maybe some snow, low 30’s

Saturday

Mostly sunny, colder, mid 20’s

Discussion

A thaw will occur for much of this week as a strong high pressure ridge will spread across the region. Temperatures will be much above normal to start the week with highs around 50 degrees and the 50 degree mark can even be surpassed over the next few days. Much colder air is likely to return to the region by the end of the week.

Video

httpv://youtu.be/FI7ahScZxTU

12:00 PM | Stratospheric warming event and widespread snowpack are signals for a return to cold weather after next week's moderation

Discussion

The weather pattern in recent days has been quite cold with below normal temperatures throughout the Mid-Atlantic region. In fact, it looks pretty cold right through Monday and we’ll likely have snow shower activity later Saturday night and early Sunday that could leave a coating in many spots. However, significant moderation in temperatures will take place next Tuesday and Wednesday and that new above-normal temperature pattern may continue right into the following weekend. What happens beyond next week’s break in the action? There are a couple of reasons to believe that a return to cold weather, perhaps even very cold, is quite probable for the Mid-Atlantic region during the middle and latter part of January.

To begin, there is a significant "sudden stratospheric warming" event now underway across the high latitudes. Temperatures over the next several days will climb rapidly in the stratosphere in the high latitudes and this type of event often results in the displacement of cold air that is normally bottled up in the polar regions to lower parts of the atmosphere (i.e. the troposphere) in the mid latitudes. In this particular case, it is likely that this warming event will result in a weakening and shifting of the polar vortex away from the North Pole and perhaps with a complete split of the vortex. Some stratospheric warming events in recent decades have, in fact, been followed by widespread very cold air outbreaks across southern Canada and the US some two to three weeks after the initial upper atmosphere warming. For example, such an event occurred during December 1984 and this led to an extremely cold January 1985 in much of the central and eastern US. (More info on recent major stratospheric warming events in the "Stratospheric Warming" video found in our "Meteorology 101" section). I believe the first sign to look for to tell if this stratospheric warming event is indeed having an effect on global weather patterns will be a change in the current slightly positive Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) index values to sharply negative readings by the middle of the month. This will likely occur as the polar jet stream generally weakens when the stratosphere warms and the polar vortex weakens. The change to these index values (AO, NAO) from positive to negative will be a pretty strong indicator that cold weather is going to return to the central and eastern US - perhaps in about two weeks or so from now.

In addition to the stratospheric warming event, another signal for cold air to return to the region after next week’s expected moderating temperatures is the extent of the snowpack currently across the nation and across the entire northern hemisphere. In fact, the nationwide snowpack of ~67% was the highest amount in the last ten years to begin a new year (and records for this only go back 10 years). Last year at this time there was only about 20% of the country with snow cover as we were experiencing a very warm winter nationwide. Even more important than the nationwide snow cover is the snowpack across the northern hemisphere which is currently running significantly above climatological normals for this time of year. Extensive snowpack like this in the northern hemisphere can have a direct contributing effect on the generation (or in this case the re-generation) of widespread cold air masses in our source regions for cold air (e.g. Canada, Siberia, Alaska and Greenland where there has been historic cold in recent days).

Stay tuned - we’ll continue to monitor all of this over the next couple of weeks.

Video

httpv://youtu.be/7mmYRFMRGXI

7:00 AM | 40's for highs in the ball park over the next several days

6-Day Forecast

Today

Mostly sunny, not as cold as recent days, highs in the low-to-mid 40's

Tonight

Mostly clear, cold, lows in the mid-to-upper teens

Saturday

Mainly sunny, cold, near 40

Saturday Night

Mostly clear, very cold, mid-teens

Sunday

Mostly sunny, milder again, mid 40’s

Monday

Partly sunny, chilly, low 40’s

Tuesday

Mostly sunny, chilly, low-to-mid 40’s

Wednesday

Partly sunny, chilly, mid 40’s

Discussion

Upper level ridging will build across Colorado from the north and west today leaving us with a dry northwest flow of air. Temperatures will modify over the next couple of days with highs at or above 40 degrees likely today and for much of the next several days.

Video

httpv://youtu.be/akKJwq6GUJI

7:00 AM | Cooler and more moist for Sunday and Monday

6-Day Forecast

Today

Mainly sunny, mild, highs in the mid 60’s

Tonight

Partly cloudy, chilly, lows in the upper 40’s

Saturday

Mostly sunny, cooler, low 60’s

Saturday Night

Becoming cloudy, chance for some rain towards morning, not quite as cold as recent nights, near 50

Sunday

Mostly cloudy, cool, chance for showers, near 60

Monday

Mostly cloudy, cool, showers possible, near 60

Tuesday

Mostly sunny, cool, mid 60’s

Wednesday

Partly sunny, still cool, low-to-mid 60’s

Discussion

Offshore winds will continue into the weekend, but then a low pressure system will approach the region by Sunday and the threat for showers will increase. A cooling trend will accompany the increase in moisture for the latter part of the weekend and early part of next week. Once that system departs, another slight warming trend will ensue come the middle part of next week.

Video

httpv://youtu.be/akKJwq6GUJI

7:00 AM | Winds still kick up a bit today; cooling trend begins this weekend

6-Day Forecast

Today

Mainly sunny, breezy, cool, highs in the mid 60’s

Tonight

Partly cloudy, cold, lows in the upper 40’s

Friday

Mostly sunny, cool, mid 60’s

Friday Night

Mostly clear, chilly, upper 40’s

Saturday

Partly sunny, cool, low-to-mid 60’s

Sunday

Partly sunny, cool, maybe some rain, low 60’s

Monday

Mostly cloudy, cool, showers possible, near 60

Tuesday

Partly sunny, still cool, near 60

Discussion

It’ll turn slightly cooler over the weekend as a cooler and more moist air mass moves into the region ahead of a low pressure system. Highs will struggle to pass 60 degrees as we begin the new work week and showers are possible.

Video

httpv://youtu.be/m1E1PiPUOig