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Thu, 28 May 2009
Philadelphia Weather Outlook- Thurs PM
Our cool weather spring will continue into the weekend as an upper trough and high pressure continues cool temperatures. The upper cyclonic flow and cool air aloft may cause some cloudiness each afternoon and possibly a shower late. Most of the weekend will be dry and cool for the end of May.
Sat 5/30: Sunny in the morning, a mix of clouds and and some qsun in the afternoon. Breezy. Chance of a shower late. High 76.
Sun 5/31: Sunny in the morning, a mix of clouds and sun in the afternoon. Breezy. High 79.
posted: May 28 2009 at 9:34 pm
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Tue, 26 May 2009Philadelphia Weather Outlook- Tues AM
Our nice weekend was the result of frontal boundary that stayed further north than expected and then moved further south than expected on Monday. So the weather we're getting today was what was originally expected to have ruined our weekend. Glad it waited until Tuesday.
About a third of an inch of rain expected today. Breezy and cool.
posted: May 26 2009 at 7:33 am
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Mon, 25 May 2009Philadelphia Weekend Weather Update- Mon AM
The uncertainty of the forecast that I spoke of several days ago was clearly evident this morning, as clear skies and a northerly dry flow has developed after the new frontal boundary passed further south of us than originally thought. (Actually, the models did show this better forecast late yesterday, but I didn't have the opportunity to update the website.)
The current frontal position is shown. This front is expected to move slowly back as a warm front later today and give us wet Tuesday.
Mon 5/25: Mostly sunny and warm. High 82.
Solar Weather: The slight recent increase in solar activity has died down and the single sunspot has disappeared. Solar activity remains low enough to continue to forecast cooler than normal weather for the balance of the spring and some much of the summer.
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posted: May 25 2009 at 9:09 am
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Sun, 24 May 2009Philadelphia Weekend Weather Update- Sun AM
The stalled weak boundary that remains near Allentown is washing out, while a more significant cold frontal boundary is developing in northwest PA this morning as high pressure tries to push in. This frontal boundary is expected to pass through and then stall to our south, acting as a focal point for rains during the week.
This new boundary will overtake the old one and is still expected to move further south, giving us showers and thunderstorms late today and night. The final position of this front will determine the temps, clouds and shower possibilities for Monday. Here's the surface map depiction:Surface Map
Sun 5/24: Partly sunny in the morning, increasingly cloudy in the afternoon with showers and thunderstorms likely late in the afternoon and night. High near 83.
Mon 5/25: Mostly cloudy with a higher chance of showers, especially in the morning. High 76.
Solar Weather: The slight recent increase in solar activity has died down and the single sunspot has disappeared. Solar activity remains low enough to continue to forecast cooler than normal weather for the balance of the spring and some much of the summer.
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posted: May 24 2009 at 8:04 am
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Sat, 23 May 2009Philadelphia Weekend Weather Update- Sat PM
The frontal boundary hasn't shifted much if at all today. Thunderstorms have been developing along this boundary, just to the north of Allentown and far west of the Susequehanna. There is instability and moisture and some lift, so thunderstorms or showers are still possible overnight.
The boundary is still expected to move further south, giving us showers late tomorrow afternoon and night. Then the boundary may move up north again on Monday, with more showers.
Sun 5/24: Partly sunny in the morning, increasingly cloudy in the afternoon with showers and thunderstorms likely later in the afternoon and night. High near 83.
Mon 5/25: Mostly cloudy with a higher chance of showers. High 73.
Solar Weather: The slight recent increase in solar activity has died down and the single sunspot has disappeared. Solar activity remains low enough to continue to forecast cooler than normal weather for the balance of the spring and some much of the summer.
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posted: May 23 2009 at 6:48 pm
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Philadelphia Weekend Weather Forecast- Sat AM
Little has changed with the stalled frontal boundary that is just to our north. It's expected to sink south tonight and there is the chance of thunderstorms this evening. Somewhat more clouds and a higher chance of showers for Sunday as the frontal boundary will be closer to us.
Dewpoints will be in the 60s today and tomorrow, instead of the more comfortable 50s, so it will feel much more like summer than spring.
Sat 5/23: Mostly sunny and warm. Some clouds in the later afternoon. Chance of a thunderstorm later tonight. High near 85.
Sun 5/24: Partly sunny in the morning, increasingly cloudy in the afternoon with showers and thunderstorms likely later in the afternoon and night. High near 83.
Mon 5/25: Mostly cloudy with a higher chance of showers. High 73.
Solar Weather: The slight recent increase in solar activity has died down and the single sunspot has disappeared. Solar activity remains low enough to continue to forecast cooler than normal weather for the balance of the spring and some much of the summer.
See microblog updates and commments about the current weather on Twitter.com Follow me as: theweatherguy
posted: May 23 2009 at 9:52 am
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Fri, 22 May 2009Memorial Weekend Weather Outlook- Fri PM
The upcoming weekend's weather will be influenced by the difficult to predict position of a weak (frontal) boundary and wind shift between two areas of high pressure- a large Bermuda high to our south and another high pressure system that will essentially stay to our north. Around the northern high will be an easterly flow near us and around the Bermuda high will be an opposite southwesterly flow. Often, this interaction results in formation of distinct areas of low pressure, but the GFS shows no such distinct development.
Instead, the GFS shows diffuse areas of light showers within this boundary area, without specific timing or exact triggers. As mentioned in my last update, this can produce weather ranging from sun, clouds, drizzle, showers. The latest models suggest that Saturday will have the most sun. Showers, if any, should occur late.
Sat 5/23: Partly to mostly sunny with a chance of very light scattered showers, most likely later in the afternoon. High near 83.
Sun 5/24: Partly sunny in the morning, increasingly cloudy in the afternoon with showers, mostly likely later in the afternoon. High near 84.
Mon 5/25: Mostly cloudy with a higher chance of showers. Some clearing possible late. High 73.
Solar Weather: The slight recent increase in solar activity has died down and the single sunspot has disappeared. Solar activity remains low enough to continue to forecast cooler than normal weather for the balance of the spring and some much of the summer.
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posted: May 22 2009 at 11:04 pm
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Thu, 21 May 2009 Memorial Weekend Weather Outlook- Thurs PM
As mentioned on Tuesday, the upcoming weekend will be a difficult forecast. Some forecasts are complicated by uncertainty in the track of distinct storms or made easy by exact location of dominant weather features, high pressure or low.
However, the upcoming weekend's weather will be influenced by the inexact placement of a weak (frontal) boundary and wind shift between two areas of high pressure- a large Bermuda high to our south and another high pressure system that will essentially stay to our north. Around the northern high will be an easterly flow near us and around the Bermuda high will be an opposite southwesterly flow. Often, this interaction results in formation of distinct areas of low pressure, but the GFS shows no such distinct development.
Instead, the GFS shows diffuse areas of light showers within this boundary area, without specific timing or exact triggers. As mentioned in my last update, this can produce weather ranging from sun, clouds, drizzle, showers. I don't think this will be a rainout by any means, and I suspect the GFS is over-doing the showers, as it often does. Exact features remain elusive. Look for updates here.
Sat 5/23: Tentative: Partly cloudy/partly sunny (more sun than clouds) with a chance of very light showers, mostly likely later afternoon. High near 83.
Sun 5/24: Tentative: Partly cloudy/partly sunny (more sun than clouds) with a chance of very light showers, mostly likely later afternoon. High near 84.
Mon 5/25: Tentative: Mostly cloudy with a higher chance of showers. High 73.
Solar Weather: The slight recent increase in solar activity has died down and the single sunspot has disappeared. Solar activity remains low enough to continue to forecast cooler than normal weather for the balance of the spring and some much of the summer.
See microblog updates and commments about the current weather on Twitter.com Follow me as: theweatherguy
posted: May 21 2009 at 5:55 pm
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Tue, 19 May 2009 Memorial Weekend Weather Outlook- Tues PM
A difficult forecast for the upcoming weekend due to a possibly easterly flow off the ocean following the passage of a cold front. High pressure will drift in from the west, but the circulation around this high will likely be from the east due to the northern position of the high. Should that happen, the easterly flow of cool air would result in some low clouds and even some light showers and drizzle this time of year. The further west you go, the better the weather, should this scenario occur. The shore may have very poor weather should this occur.
With this sort of weather situation, it's easy for the configuration to change if the high drifts slightly further south than now forecast. We could end up with a splendid sunny and dry weekend. Too early to be sure.
Sat 5/23: Tentative: Partly cloudy chance of very light showers. High near 70.
Sun 5/24: Tentative: Partly cloudy, chance of light showers. High 68.
Mon 5/25: Tentative: Mostly sunny and continued cool.
Solar Weather: There's been the first increase in solar flux in over a year with the recent development of some active regions of sun producing the first sunspot in quite awhile. This increase in activity means that Solar Cycle 24 is probably starting in earnest now. However, the solar flux remains low, still at a level near 74. Solar activity remains low enough to continue to forecast cooler than normal weather for the balance of the spring and some much of the summer.
See microblog updates and commments about the current weather on Twitter.com Follow me as: theweatherguy
posted: May 19 2009 at 8:17 pm
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Sun, 17 May 2009Philadelphia Weekend Weather Forecast - Sun AM
A cold front is slowly moving through PA. There was a question about when this front would finally pass through and it seems that the 10AM time frame might have been too early. Rain should stop between 10 and noon today, although clouds clear out very slowly.
Sun 5/17: Cloudy with showers and thunderstorms ending between 10 and noon, windy and cool. Much of the day cloudy. High 61.
Solar Weather: There's been the first increase in solar flux in over a year with the recent development of some active regions of sun producing the first sunspot in quite awhile. This increase in activity means that Solar Cycle 24 is probably starting in earnest now. However, the solar flux remains low, still at a level near 74. Solar activity remains low enough to continue to forecast cooler than normal weather for the balance of the spring and some much of the summer.
See microblog updates and commments about the current weather on Twitter.com Follow me as: theweatherguy
posted: May 17 2009 at 8:42 am
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Sat, 16 May 2009Philadelphia Weekend Weather Forecast - Sat AM
An approaching cold front on Saturday afternoon will bring rain through Saturday night and end Sunday morning, earlier than first shown by the models.
Sat 5/16: Cloudy. Showers and thunderstorms move in, most likely between 3 and 5 PM and continues through the night. High 77
Sun 5/17: Cloudy with showers and thunderstorms ending by 10AM, then windy and cool. High 62.
There's been the first increase in solar flux in over a year with the recent development of some active regions of sun producing the first sunspot in awhile. The solar flux has increased just a bit. Solar Cycle 24 is probably starting now. Solar activity remains low enough to continue the forecast of cooler than normal weather overall.
See microblog updates and commments about the current weather on Twitter.com Follow me as: theweatherguy
posted: May 16 2009 at 11:20 am
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Fri, 15 May 2009Philadelphia Weekend Weather Forecast - Fri PM
An approaching cold front on Saturday afternoon will bring rain through Saturday night into the first half of Sunday. It seems possible that the models might be over-extending the rain into mid day Sunday, so I think there is uncertainty about when the rain will stop.
Sat 5/16: Chance of a brief light shower early, then cloudy with some breaks in the overcast skies possible in the morning, then cloudy by afternoon. Showers and thunderstorms move in, most likely between 3 and 5 PM and continues through the night. High 77
Sun 5/17: Cloudy with showers and thunderstorms during most of the morning, ending about noon. Some clearing possible during the mid to late afternoon. Windy and cool. High 60.
There's been the first increase in solar flux in over a year with the recent development of some active regions of sun producing the first sunspot in awhile. The solar flux has increased just a bit. Solar Cycle 24 is probably starting now. Solar activity remains low enough to continue the forecast of cooler than normal weather overall.
See microblog updates and commments about the current weather on Twitter.com Follow me as: theweatherguy
posted: May 15 2009 at 6:42 pm
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Philadelphia Weekend Weather Forecast - Fri AM
The difficult to pin down pattern of frontal passages over the weekend remains a bit elusive, but I'll try to give a forecast.
The front that moved through last night will be far enough south to keep much of Friday and and most of Saturday without rain. However, any sun today (Friday) could cause enough stability to set off a thunderstorm. A cold front will move through late Saturday bringing showers and thunderstorms. Still some uncertainty with details with this forecast.
Sat 5/16: Cloudy but with some breaks in the overcast skies possible in the morning. Chance of showers and thunderstorms by afternoon. Exact timing uncertain, but increasingly probable late afternoon. High 76
Sun 5/17: Cloudy with showers and thunderstorms ending during most of the morning. Some clearing possible during the mid to late afternoon. Cool. High 64.
There's been the first increase in solar flux in over a year with the recent development of some active regions of sun producing the first sunspot in awhile. The solar flux has increased just a bit. Solar Cycle 24 is probably starting now. Solar activity remains low enough to continue the forecast of cooler than normal weather overall.
See microblog updates and commments about the current weather on Twitter.com Follow me as: theweatherguy
posted: May 15 2009 at 6:06 am
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Thu, 14 May 2009Philadelphia Weekend Weather Forecast - Thurs AM
Today's (Thurs) weather captures the difficulty of predicting the current pattern. The models had us dry for this morning, but it's raining out. The models had it wet for much of Friday, but now, Friday is supposed to be dry as is much of Saturday.
The front that moves through tonight and Friday morning now is supposed to be far enough south to keep much of Friday and and most of Saturday dry. A cold front will move through on Sunday bringing showers. Forecast uncertain. Stay tuned.
Sat 5/16: Bright skies, with breaks of sun, especially in the morning. Chance of showers in the late afternoon. I think most of Saturday will be dry. High 76.
Sun 5/17: Cloudy with showers and thunderstorms. Cool. High 63.
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posted: May 14 2009 at 7:07 am
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Wed, 13 May 2009Philadelphia Weekend Weather Outlook - Wed PM
The weekend weather forecast continues to look a bit uncertain. A front moves through Friday and stalls to our south, then moves back over us on Saturday before another cold front moves through on Sunday. This scenario isn't too much different than the one that caused the period of rainy weather last week. Saturday morning looks dry, but showers can develop during the afternoon. Sunday looks like it will also have clouds and showers. Exacting timing is uncertain and this sort of pattern can cause a range of weather from clouds, drizzle and showers to large breaks in the action with considerable sun. Forecast uncertain. Stay tuned.
Sat 5/16: Bright skies, some sun in the morning possible. Chance of showers in the afternoon. I think most of Saturday will be dry. (this is an educated guess). High 80.
Sun 5/17: Cloudy with showers and thunderstorms mostly in the morning, some brighter skies in the afternoon. High 70.
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posted: May 13 2009 at 4:13 pm
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Tue, 12 May 2009Philadelphia Weekend Weather Outlook - Tues PM
The weekend weather forecast continues to look uncertain, as an upper air cyclonic flow and moisture moving up from the southwest before an approaching frontal boundary gives us a chance of showers both Saturday and Sunday, especially Sunday. Details unclear and timing of the showers is expected to change. Stay tuned.
Sat 5/16: Forecast uncertain. A mix of sun and clouds. Showers possible especially in the afternoon.
Sun 5/17: Forecast uncertain. Cloudy with a good chance of showers and thunderstorms.
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posted: May 12 2009 at 8:58 pm
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Philadelphia Weekend Weather Outlook - Tues AM
A complex series of frontal passages and low pressure systems are depicted by the models for this weekend. Several of the low pressure systems scoot to our south. (The models did not accurately capture Monday's light shower forecast and low pressure placement to our south.) Confidence in the accuracy of the forecast for this coming weekend is not high at this time. It looks like showers for Saturday and then more clouds and showers later Sunday, but I expect the details to change.
Sat 5/16: Forecast uncertain. Showers especially in the afternoon.
Sun 5/17: Forecast uncertain. Some sun early, then clouds and showers later in the day.
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posted: May 12 2009 at 9:31 am
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Sat, 09 May 2009Philadelphia Weekend Weather Update - Sat PM
Our rainy streak has ended. High pressure gives us nice but windy weather for Sun.
Sun 5/10: Partly to mostly sunny, windy and cooler. High 71.
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posted: May 09 2009 at 10:44 pm
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Philadelphia Weekend Weather Update - Sat AM
More sun today than originally expected. So temps in mid 80s. A fair amount of instability so a thunderstorm is still a possibility but not at all certain.
Sat 5/7: Sun and some clouds, especially early afternoon. There is a chance of a very late afternoon or evening thunderstorm but not a certainty. High near 85.
Sun 5/8: Partly to mostly sunny, windy and cooler. High 71.
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posted: May 09 2009 at 10:05 am
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Fri, 08 May 2009Philadelphia Weekend Weather Update - Fri PM
Just as the NAM model was looking good, it fell short for this evening-- the showers look like they went to the north, as predicted by the GFS. The GFS is having trouble with the approaching mesoscale disturbance entering West Virginia. It spits out 0.04 inches of rain every 6 hours through early Saturday. Then nothing. The NAM seems to show the same thing. So from a wet Saturday, it appears we may have little if any significant precip. The NAM shows instability for Saturday afternoon, so a thunderstorm is still possible.
Sat 5/7: Cloudy early, then a mix of clouds and some sun possible. Showers look much less likely, but there is a chance of a late afternoon thunderstorm. High near 80.
Sun 5/8: Partly to mostly sunny, windy and cooler. High 69.
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posted: May 08 2009 at 8:31 pm
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Philadelphia Weekend Weather Outlook - Fri PM
The almost record-setting string of rainy days should end this Sunday. This evening, the NAM has some heavy showers and again late morning on Saturday. (The GFS shows much lower amounts of precip in all time frames. The NAM has been doing better with this rainy pattern.) Sunday will be the better day, as things clear out and sunshine is a good bet.
Sat 5/7: Cloudy with showers by late morning or early afternoon continuing into the evening. Mild. High 75.
Sun 5/8: Clearing early, then mostly sunny breezy and pleasant. High 71.
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posted: May 08 2009 at 2:04 pm
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Wed, 06 May 2009Philadelphia Weekend Weather Outlook - Wed AM
The current pattern of a stalled boundary with areas of low pressure developing and riding up to our area continues through the weekend. Saturday will have increasing clouds and rain by afternoon, as yet another disturbance affects us. Sunday will be the better day, as things clear out and sunshine is a good bet.
Sat 5/7: Cloudy with showers by late morning or early afternoon continuing into the evening. Mild. High 75.
Sun 5/8: Clearing early, then mostly sunny and pleasant. High 71.
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posted: May 06 2009 at 10:21 am
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Sat, 02 May 2009Philadelphia Weekend Weather Forecast - Sat AM
A stalled front acting as a focal track for the development of small waves of low pressure will result in showers and thunderstorms for the weekend. The weather we had on Friday will likely be with us today, Saturday, with times of showers, sun, dark clouds, etc.
Unfortunately, the computer models will have a tough time with the small scale aspects of the weather. So exact timing will be difficult. Already the GFS and NAM have flipped from heavier showers in the late afternoon today to less likely showery activity once the morning showers clear out.
For Sunday, the models have been consistent with predicting a heavier rain starting in the morning.
Sat 5/1: Clouds, showers and even some sun and bright spots. High 65. (Most rain tapering after 8 AM. Most of the day without showers.)
Sun 5/2: Cloudy with rain. High 61.
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posted: May 02 2009 at 7:28 am
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Fri, 01 May 2009Philadelphia Weekend Weather Forecast - Fri PM
The general scenario of a stalled front acting as a focal track for the development of showers and thunderstorms has remained unchanged since my last forecast. Already, the development of a line of showers and thunderstorms to our west at 6:30 PM doesn't jive with the GFS model run from this afternoon.
This means the small scale aspects of the weather pattern will be difficult to pin down. The weather we had today (Friday) will be representative of the the weather we can expect on Saturday. There will be times of showers, bright spots, some sun, and dark clouds.
For Sunday, the models have been consistent with predicting a heavier rain starting in the morning.
Sat 5/1: Clouds, showers and even some sun and bright spots. High 65. (Most likely time of showers is the mid to late afternoon. The morning will be cloudy, but not raining.)
Sun 5/2: Cloudy with rain. High 61.
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posted: May 01 2009 at 7:09 pm
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Disclaimer: I am not a meteorologist and provide this information as a hobby and for entertainment (mostly my own :-) . While attempts are made to predict the weather as best as I can, use at your own risk! I am NOT responsible for any direct or indirect consequential injury/damages due to your use of these forecasts. Always check the NWS Official Forecast for your final plans.
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