Phillyweather.net: The Delaware Valley's Weather Center

Monday, July 13, 2009

Coolest Summer This Decade? Jury Is Still Out For Now

While we still have half the summer left in Philadelphia, the first half of meteorological summer in Philadelphia has been the coolest since 1982. The average high temperature in Philadelphia so far has been just above 80.0 degrees, which is the coolest since 1982's 79.2 degree reading for the same stretch of time. 1982 wasn't the coolest summer on record in Philadelphia (that honor belonged to the summer of '27) but at the current pace and assuming we stay as cool as we have so far this summer (that might be tough to do), Philadelphia could end up with one of the coolest summers since the official ob site moved out to the Airport in 1940.

The second half (and a couple days) of meteorological summer is warmer than the first half on average by about three degrees (76.9 here on out compared to 73.9 through today). If we were to extrapolate merely normal conditions between now and the end of August we end up with a final average temperature for the summer of 74.7 degrees, which would end up being the third coolest this decade behind 2000 and 2004 and about a degree below average overall.

For the sake of comparison, the chart up above compares the average daily high and average daily low for the entire summer this decade, as well as the summer in Philadelphia through Saturday. If we extrapolate the average of three degrees warmer from here on out, Philadelphia ends up with an average summer high of 83 degrees, which is still quite cool compared to other summer readings this decade. However, that's based on assumptions...over the next 45 days and change there could be a lot of change in the pattern...or merely more of the same.

The interesting statistic is that our high temperatures this summer so far have been 5.9 degrees cooler than through the same amount of time last year. As you may remember, we dealt with some impressive heat in early June 2008 which helped bolster those readings quite a bit. While our 'summer' seemed to occur more in late April this year (thanks to that heat wave the last few days of the month), there still is plenty of time to see a role reversal in temperatures. Unfortunately for heat mongers, the pattern that has been set in place for much of the summer will not be changing in the next several days...so the odds of being one of if not the coolest summer this decade will continually to slowly increase.

Weather News: Wake Up with Al (and Stephanie)

The Weather Channel is making more changes to its lineup. Jim Cantore was recently teamed up with Alexandra Steele to do weather in the evenings, now Stephanie Abrams gets bumped from evenings to do an hour of weather in the morning with NBC's Al Roker. "Wake Up with Al" debuts a week from today, running from 6-7 AM on the East Coast (repeating a few hours later for the West Coast folk) and is TWC's first weather show to feature two on camera personalities for a full hour in separate locations and is also TWC's first new show since being purchased by NBC Universal last year.

Roker will be broadcasting from 30 Rock, with Abrams from the TWC studios in Atlanta. Capitalweather Gang has a nice interview with Stephanie Abrams running online that promos the show's debut.

In other weather news, there continues to be speculation about what "El Nino 2" can do to weather patterns in the tropical Atlantic. El Nino 2 (as it seems to be called now) forms farther west (aka a West Based Nino) as opposed to a Nino whose warmest waters are closer to the South American coastline. This was discussed in some detail here last week as well.

Frosty Summer? Frost struck Prince Edward Island, Canada, last week for the first time in recorded annals during the month of July. A record low of 3.8 degrees Celsius was set at Charlottetown (the provincial capital) last Wednesday morning. The record chill in PEI was described as "a significant event" by Bob Robichaud, a meteorologist at Environment Canada.

July 14th, 2009 Forecast

While today was a relatively nice day in the region, a few evening thunderstorms could give pause to those walks, jogs, and outdoor events that will take place. As of now, only a couple of showers have popped up in Delaware (as of 3 PM) but a few more are possible as the afternoon drifts into evening. Temperatures this afternoon are in the lower and middle 80's across the region under a mix of sun and clouds, with similar weather (but more sunshine) expected tomorrow.

Tonight: Any scattered evening thunderstorms should depart the region around or just after midnight, leaving a partly cloudy sky. Like last night, temperatures will be coolest to the north and northwest of Philadelphia. Lows will drop in the Lehigh Valley into the mid 50's, with low 60's expected around the city overnight.

Tuesday: We should see a bit more sunshine than today as high pressure works through the region. Temperatures should jump into the mid 80's nearly everywhere, with around 80 at the Shore thanks to west winds.

Our next chance of storms could be Wednesday afternoon and evening as a warm front lifts through the Delaware Valley, with another chance of storms on Thursday as a "cold" front sags southeast. We could approach 90 in a few spots Thursday afternoon ahead of the front but right now the best chance of any 90 degree heat looks to be across interior sections of Delaware and points south.

Deliveries: Congrats to CBS 3's Doug Kammerer and family, whose wife gave birth to a baby girl yesterday morning!

Updating Monday's Weather

We start the work week to a mixed bag of cloud conditions depending on where you live. Saturday's storm complex was along a frontal boundary that stalled out to our south, where a second storm complex's cloud debris spread eastward along the front. While a few dodge em storms occurred over the Delmarva last night, the rest of the region was generally dry.

Temperatures are based pretty much on who went mostly clear and who had some high level clouds. 50's were common north of Philadelphia, with 60's in the city and south. This will lead to today's mix of clouds and sun in the forecast, however areas to the north could see more sun to start as skies are more clear to the north.

Adding to the fun is an upper level disturbance that will slide southeast in the jet flow. This disturbance may fire off a few afternoon and evening thunderstorms across Pennsylvania, which could slip southeast into the city in time for dinner. The NAM and GFS computer models have shown these storms for the last couple of runs. While they don't look as potent as Saturday's storms, there is enough atmospheric juice and instability that a couple of them (as always, this is summertime after all) could be gusty as they fire up.

For full array of radar and satellite information, check out current.phillyweather.net.

Sunday, July 12, 2009

Weather Rewind, July 5-11, 2009

Despite a week long run of 80+ temperatures, being in the heart of summer usually means you need to be a bit warmer than 80 for it to be 'average' around here. Temperatures averaged nearly four degrees below the water line this past week, with only Tuesday's 88 degree high the lone day above where we usually stand this time of year. Not that I hear many complaints about the lack of 90+ heat from anyone, of course.

Other than Saturday night (and into Sunday morning's) storms, the week was generally dry. We did have one round of storms on Tuesday afternoon that fired up north of Philadelphia. However, the rest of the week managed to be dry in Philly overall.