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Mon, 26 May 2014
New URL for theweatherguy
Effective May 19, 2014, theweatherguy's blog is now posted using WordPress and can be found at http://theweatherguy.net/blog
Please bookmark the new URL: http://theweatherguy.net/blog
posted: May 26 2014 at 12:05 pm
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Tue, 20 May 2014theweatherguy's NEW WEATHER BLOG
Effective May 19, 2014, theweatherguy's blog is now posted using WordPress and can be found at http://theweatherguy.net/blog
Please bookmark the new URL: http://theweatherguy.net/blog
posted: May 20 2014 at 10:46 pm
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Fri, 16 May 2014Philadelphia Weekend Weather Forecast - Fri PM
High pressure builds in for Saturday. A reinforcing cold front moves through early Saturday evening with some clouds. Sunny and pleasantly cool for Sunday.
Sat 5/17: Mostly sunny. Cloudiness very late afternoon/early evening. High 74.
Sun 5/18: Sunny and pleasantly cool. High 69.
posted: May 16 2014 at 9:20 pm
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Sat, 10 May 2014Philly Weather Update
Mid-level cloudiness today, with some bright spots in the morning. Thickening clouds in the afternoon with showers/thunderstorms breaking out about 2-3 PM.
posted: May 10 2014 at 8:54 am
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Fri, 09 May 2014Philadelphia Weekend Weather Forecast - Fri PM
A weak frontal boundary moves through late Saturday, preceded by showers and thunderstorms. High pressure builds in for Sunday.
Sat 5/10: Some showers before daybreak, then mostly cloudy. A chance of showers and thunderstorms mostly during the late afternoon and evening. High 76.
Sun 5/11: Sunny and warm. High 81.
posted: May 09 2014 at 9:49 pm
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Fri, 25 Apr 2014Philadelphia Weekend Weather Forecast - Fri PM
Low pressure with an associated cold front passes through this evening. Weak high pressure builds in for early Saturday, but another upper air disturbance and front rotates through Saturday afternoon, with a chance of showers. Cooler clear conditions for Sunday.
Sat 4/26: Sunny pleasant early much of the day, then some increase in clouds late afternoon with a chance of showers. High 68
Sun 4/27: Sunny and pleasant. High 64.
posted: Apr 25 2014 at 7:26 pm
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Fri, 18 Apr 2014Philadelphia Weekend Weather Forecast - Fri AM
A low pressure system along the southeastern coastline, originally expected to move up the coast, is now expected to be suppressed to the south by high pressure building in from the north.
The models are maintaining clear skies and dry conditions, but the proximity of the low pressure system and the expected easterly wind flow around the high may bring more clouds than the models currently forecast. These easterly wind flows can cause havoc with forecasts.
Sat 4/19: After some early morning cloudiness, becoming sunny and seasonably mild. High 65
Sun 4/20: Sunny and pleasant. High 64.
posted: Apr 18 2014 at 9:53 am
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Fri, 11 Apr 2014Philadelphia Weekend Weather Forecast - Fri PM
A weak front moves through tonight with light showers. High pressure builds in for Saturday. A weak warm front moves through Saturday night. A southwesterly flow of mild air moves in for Sunday.
A strong front moves though on Tuesday.
Sat 4/12: Sunny and mild. High 74.
Sun 4/13: Mostly sunny and warm. High. 78.
posted: Apr 11 2014 at 10:21 pm
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Sat, 05 Apr 2014Philadelphia Weekend Weather Forecast - Sat AM
High pressure building in today will bring fair skies and windy conditions. Winds settle down for Sunday.
Temperatures will be near average for this time in April. Average high temp is about 60.
Sat 4/5: Sunny and somewhat windy. Near average temps. High 58.
Sun 4/6: Sunny and pleasant. High 60.
posted: Apr 05 2014 at 8:57 am
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Fri, 28 Mar 2014Philadelphia Weekend Weather Forecast - Fri PM
A closing off upper air low-pressure system will induce a surface low to form directly over us during the weekend. The combined upper low and surface low pressure system will be slow to move and will bring periods of rain, sometimes heavy, over the weekend. It's rare to see POPS at 100% for several periods in the model output statistics but the current GFS MOS has 36 hours of 100% precipitation probability!
So the strange weather continues...
Sat 3/29: Cloudy in the morning with rain developing by afternoon. High 54
Sun 3/30: Cloudy and stormy with rain, possibly heavy. Windy. High 56.
posted: Mar 28 2014 at 3:49 pm
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Fri, 21 Mar 2014Philadelphia Weekend Weather Forecast - Fri PM
A weak cold front moves through Saturday morning, with clouds and maybe a light sprinkle. Skies partially clear in the afternoon.
Another reinforcing front passes through early Sunday morning with more clouds and cooler temperatures. (Average high temp is 56.)
Sat 3/22: Cloudy in the morning, Breezy. Chance of a quick sprinkle. Partly sunny in the afternoon. High 65.
Sun 3/23: Considerable cloudiness in the morning. Skies clear during the afternoon. Much cooler. High 46.
posted: Mar 21 2014 at 7:17 pm
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Sun, 16 Mar 2014Philly Winter Weather Update - Sun 10 PM
The latest NAM shows 3-4 inches of snow from the very southern part of Philadelphia with more further south. There is a drop-off of snow even over short distances to Willow Grove, where an inch or so is possible. This storm is similar to the one of two weeks ago, where the northern suburbs got little and Delaware/South Jersey had several inches.
Snow ends during the early morning.
.
posted: Mar 16 2014 at 10:18 pm
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Philly Winter Weather Update - Sun 11 AM
The latest NAM has flipped again to about 3 inches of snow from the very southern part of Philadelphia southward. There is a sharp cut-off of snow even in the short distant to Northeast Philadelphia and Chestnut Hill. This storm is similar to the one of exactly two weeks ago, where the northern suburbs got little if anything and Delaware/South Jersey had several inches. Like that storm, there were changes in the position of the boundary between dry cold and moisture as little as 12 hours before the event. So additional changes in the forecast storm are possible.
Stay tuned for any changes about this time tonight.
posted: Mar 16 2014 at 10:55 am
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Sat, 15 Mar 2014Philly Winter Weather Update - Sat 11 PM
The latest NAM again suppresses the snow to south of Philadelphia. So now, it appears it will miss us.
Stay tuned for any changes.
posted: Mar 15 2014 at 11:00 pm
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Philly Winter Weather Update - Sat 6 PM
The models have been less than consistent predicting the possible snow for Monday. This morning's NAM model kept the snow to our south. This afternoon's NAM and GFS both show snow, starting Sunday night and ending by noon on Monday. Both models now show about 0.40 inches water with very cold temperatures. It's likely that there will be 3-4 inches of snow by Monday morning. Accumulations in March are tough to predict because the insolation through the clouds can allow melting on roadways during the day.
Despite what I'm hearing right this moment on Channel 10, this won't be "wintery mix" This will fall as snow. How much is still uncertain.
posted: Mar 15 2014 at 6:22 pm
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Fri, 14 Mar 2014Philadelphia Weekend Weather Forecast - Fri PM
A weak upper air disturbance will move through Friday evening, perhaps with some light sprinkles. Skies clear Saturday, as a westerly flow of air comes in. Temperatures will drop as the winds become more northerly later Saturday and Sunday. An approaching low pressure system from the south will bring cloudiness in on Sunday with some snow possible Sunday night.
The low from the south may or may not become better organized Sunday night. Right now just an inch or two of snow is possible by Monday morning. We will need to watch this situation because this could turn into a more significant snow producer. There is also uncertainty about snow later Monday into Tuesday!
Sat 3/15: Becoming mostly sunny and milder. Windy! High 57.
Sun 3/16: Some sun early, then becoming cloudy. Cold. High 44. A chance of light snow during the evening.
posted: Mar 14 2014 at 7:22 pm
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Sun, 02 Mar 2014Philly Winter Weather Update - Sun 10:30 PM
The latest GFS model data just available continues the trend showing the greatest precipitation to occur south of PA, into DE and MD. The cold air will suppress the major frontal moisture convergence south of PHL.
It currently appears that PHL will get around 4 inches. Areas just north, in Montgomery and Bucks counties will get 2 inches or less.
posted: Mar 02 2014 at 10:43 pm
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Philly Winter Weather Update - Sun 9PM
The latest NAM model data just available continues the trend showing the greatest precipitation to occur south of PA, into DE and MD. The cold air will suppress the frontal moisture convergence to our south
As I've mentioned for days, this particular scenario is very hard to predict accurately in advance, and it doesn't surprise me that this "major" storm for Philadelphia will become a fizzled storm for the immediate PHL area. (For Wilmington and Baltimore and Cape May, a still a significant storm.)
It currently appears that the immediate city will get around 4 inches, with even less in the northern suburbs.
posted: Mar 02 2014 at 9:10 pm
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Philly Winter Weather Update - Sun 12PM
This morning's models are out and the NAM remains emphatic about keeping the heavy precipitation to our south, near Baltimore. The GFS has also cut back on the expected snow totals as well. 4-7 inches is most likely at this point, with emphasis on the lower range. Totals will be lower as one goes further north of PHL.
The position of the stalled front and area of maximum convergence may still change and some uncertainty about snowfall amounts remains. Stay tuned.
posted: Mar 02 2014 at 12:16 pm
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Sat, 01 Mar 2014Philly Winter Weather Update - Sat PM
This afternoon's model runs underline the changeability and uncertainty of this type of stalled-front convergence precipitation event.
The models are now suggesting that the stalled front and the convergence zone will be further to our south. As a result, the amount of snow for Philadelphia looks to be much less than previously predicted. Currently, 4-6 inches looks like a better bet, with less further north.
Things may continue to change and uncertainty about snowfall amounts will continue. Stay tuned.
posted: Mar 01 2014 at 6:15 pm
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Philly Winter Weather Update - Sat AM
The models continue to predict a heavy snowfall for the Philadelphia area from late Sunday night through early afternoon Monday. Heaviest snow to fall during the morning hours of Monday. Still differences in the models with exact placement of the heaviest snow, but last night's GFS has the precipitation bullseye right over Philadelphia. Depending on the model, 6-8 inches of snow or 10-12 inches is what is currently expected.
As mentioned yesterday, this system is very different than past storms and uncertainties remain. Much of this storm's structure is really the result of a slowing frontal boundary being over-run by moisture, vs a compact low pressure system moving near us. This sort of scenario can result in forecast errors, since exact placement of the frontal boundary is difficult to forecast in advance with high precision. The predicted area of maximum convergence of cold and moisture may change. Stay tuned.
posted: Mar 01 2014 at 7:55 am
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Fri, 28 Feb 2014Philadelphia Weekend Weather Forecast - Fri PM
March will come in like a lion. The cold air mass over us will provide continued cold temperatures on Saturday. An approaching frontal boundary on Sunday will bring clouds followed by light rain towards evening. The frontal boundary is expected to sink to our south during the nighttime hours and by Monday morning a developing wave along the frontal boundary will bring snow. The GFS model cranks out quite a bit of precipitation, as snow, ending Monday evening.
Of all of the weather 'events' of this winter, this potential snowfall has the greatest amount of uncertainty regarding precipitation amounts and precipitation type (snow sleet freezing rain). With some of the energy still off of the CA coastline, an accurate prediction is not possible at this time. The interplay between cold air moving in and moisture approaching from the southwest will be complex and slight changes will result in big weather differences. Additionally, location will be a factor, where 50 miles can make a significant difference in heavy snow vs sleet vs freezing rain. Stay tuned.
Sat 3/1: Sunny in the morning. Some cloudiness mixes in during the afternoon. High 30.
Sun 3/2: Cloudy with rain or sleet developing late afternoon. High 37. Sleet, rain or freezing rain changes to snow at night, towards Monday morning. Snow, 6 inches or more during Monday. Stay tuned.
posted: Feb 28 2014 at 4:30 pm
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Mon, 17 Feb 2014Philly Winter Weather Update - Mon 11 PM
snow totals for tomorrow looking very uni mpressive. maybe an inch.
posted: Feb 17 2014 at 10:52 pm
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Philly Winter Weather Update - Mon 5 PM
This afternoon's models are looking less impressive. Based on the afternoon model runs, expect only 2-3 inches.
posted: Feb 17 2014 at 5:12 pm
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Philly Winter Weather Update - Mon 12 PM
Once again, the Philadelphia area will be threatened by snow. The latest NAM model shows a small disturbance moving across our area, but undergoing intensification as it reaches the coast. QPF values over 0.60 inches water, falling as snow. The GFS has much less intensification and much lower QPF values (0.25). This winter, the NAM has been remarkably good at predicting snowfall. So right now, 3-6+ inches of snow possible for our area, starting before daybreak and ending late morning.
Both models have snow starting before daybreak, so we will wake up to about 3-4 inches of snow. Updates later.
posted: Feb 17 2014 at 12:43 pm
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Fri, 14 Feb 2014Philadelphia Weekend Weather Forecast - Fri PM
Low pressure moving to our south on Saturday will bring snow to our area. The NAM has the snow in the afternoon, while the GFS has has snow in the morning and afternoon. Both models crank out about .30 inches water, but temps near or above freezing and insolation through clouds with the higher February sun will limit accumulations on roadways. 2-4 inches looks possible on surfaces other than roadways.
A cold front moves through after the low passes, dropping temperatures for Saturday night through Monday. A significant warming trend starts midweek.
Sat 2/15: Cloudy with snow, 2-4 inches on grassy surfaces. Deep cold returns at night.
Sun 2/16: Sunny and very cold. High 28.
posted: Feb 14 2014 at 7:32 pm
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Thu, 13 Feb 2014Philly Winter Weather Update - Thurs 4 PM
The latest NAM has become available- another 4-6 inches of snow tonight! Temperatures to get colder and support a change back to snow.
Even more incredible- the NAM is showing about 3-5 inches of snow for Saturday morning!
posted: Feb 13 2014 at 5:07 pm
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Philly Winter Weather Update - Thurs 11 AM
The QPF values for the NAM were a much closer to the snowfall totals this morning compared to the GFS model. In the Chestnut Hill area, we have about 10 inches of snow.
The latest NAM model data has little if anything for the afternoon with temps near or above freezing. The NAM shows snow starting again this evening as temperatures fall- another 3-5 inches of snow this evening by about midnight!
Even more incredible- the NAM is showing about 3 inches of snow for Saturday morning!
posted: Feb 13 2014 at 11:02 am
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Wed, 12 Feb 2014Philly Winter Weather Update - Wed 7 PM
Still huge differences in the models. If the NAM is correct, we will wake up tomorrow to a foot of snow with heavy snow falling. If the GFS is correct, we will wake up to 3 or 4 inches. Both have a changeover to sleet and rain during the day, then a few inches of snow Thursday night.
In past years, huge differences between the GFS and the NAM models have often resulted in storms did not live up to the hype. Will be interesting to see how things play out. The next model runs come out about 9 PM and 10:30 PM tonight.
posted: Feb 12 2014 at 7:24 pm
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Tue, 11 Feb 2014Philly Winter Weather Update - Tue 11 PM
Big differences between NAM and GFS models- the latest GFS has only a few inches of snow mixing with sleet during the day.
In past years, huge differences between the GFS and the NAM models have often resulted in storms that fizzled out and did not live up to the hype. Will be interesting to see if things come into better agreement tomorrow.
posted: Feb 11 2014 at 10:51 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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