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Miscellaneous
Mon, 31 Jul 2006
Breaking 100? - Monday AM
The current hot circulation continues to be predicted to be even hotter on Tues and Wednesday.
Here are the current Model Output Statistics (MOS) for Philadelphia (airport):
Today, Monday: GFS 95 Eta 93 GFS-LAMPS: 94
Tuesday: GFS 101 Eta 99
Wednesday: GFS 103 Eta 102
The Model Output Statistics (MOS) is what is used the National Weather Service and others to predict the high temperatures for the day. (Lately, the MOS predicted values have been higher than the actual high temperatures by a few degrees.)
For today, the WRF does show the possibility of scattered thunderstorms in our area between 5 and 8 PM, but the areal coverage will not be widespread.
posted: Jul 31 2006 at 6:18 am
[/weather/jun06] permanent link
Sun, 30 Jul 2006Hot Days - Sunday AM
Latest models have diminished the hight temps (somewhat) for Philadelphia for today, Sunday, and Monday. Low 90s with dewpoints in the upper 60s at the height of the temperature range. Thunderstorms appear unlikely today in and around Philadelphia.
For Tuesday and Wednesday, the GFS model statistics are still pushing 101 and 102 (the NAM has 99). We'll see if it really gets that hot.
Sun 7/30: Mostly sunny, some clouds and haze. High 93. Shore: similar temps, higher dewpoints.
posted: Jul 30 2006 at 6:43 am
[/weather/jun06] permanent link
Sat, 29 Jul 2006Heat Wave - Sat PM
It's summer! But we're in a hot stretch. Currently the high temperatures being forecast by the models are a bit higher than we're actually experiencing. Today's models had highs around 93 and tomorrow 96. We got to 91-92. (For Tuesday and Wednesday, the models are forecasting highs of 101....the last time we saw those numbers we hit actual highs of 96-98.)
For Sunday, the models are showing dewpoints in the very uncomfortable 70-72 and temps in the mid 90s. There is a trigger for thunderstorms on Sunday and the current WRF is suggesting some storms about 4-5 PM, but not everyone will necessarily see one.
Sun 7/30: Sunny in the morning, partly sunny in the afternoon. Hazy, Hot, humid. High 95. Very uncomfortable dewpoints around 72. Chance of a late afternoon thunderstorm in spots. Shore: similar temps, higher dewpoints, with thunderstorms less likely.
I'll update the likelihood of thunderstorms tomorrow morning.
posted: Jul 29 2006 at 3:31 pm
[/weather/jun06] permanent link
Weekend Weather - Sat AM
It's summer! Today will be dry and hot, as a westerly flow of hot humid air will be over us. Hotter and more humid on Sunday, as the temperatures and dewpoints will be increasing each day. A weak disturbance passing through to our north may trigger a thundershower on Sunday, but not likely.
Sat 7/29: Sunny, hazy hot and humid. High 93. Dewpoints moderately uncomfortable at 67 to 68. Shore: not much of a seabreeze. Temps near 90.
Sun 7/30: Sunny in the morning, partly sunny in the afternoon. Hazy, Hot, humid. High 95. Uncomfortable dewpoints near 70. Chance of a late afternoon/evening thunderstorm. Shore: similar with thunderstorms even less likely.
posted: Jul 29 2006 at 7:34 am
[/weather/jun06] permanent link
Fri, 28 Jul 2006Weekend Weather - Fri PM
It's summer! Bermuda high firmly established will provide a hot humid flow. ....A chance of isolated thundershowers late afternoon, especially on Sunday as a weak disturbance shears off to our north.
Sat 7/29: Sunny, hazy hot and humid. High 92. Dewpoints upper 60s.
Sun 7/30: Sunny in the morning, partly sunny in the afternoon. Hazy, Hot, humid. High 93. Dewpoints near 70. Chance of a late afternoon thunderstorm.
posted: Jul 28 2006 at 6:39 pm
[/weather/jun06] permanent link
Tue, 25 Jul 2006Quiet Summer Weather- Tues PM
A typical pattern for summer....hot humid and a chance of isolated thundershowers late afternoon.
The weekend looks good, but we have to watch a frontal boundary that may (or may not) slip through here on Saturday.
posted: Jul 25 2006 at 6:46 pm
[/weather/jun06] permanent link
Mon, 24 Jul 2006Week Weather Outlook- Mon AM
A typical pattern for July is in store for us this week. Increasing temperatures and humidity, with dewpoints getting into the uncomfortable range by Thursday. Afternoon and evening scattered thunderstorms will be possible almost every day, from Tuesday through Saturday.
The GFS has a weak low pressure system moving in from the south late Tuesday into Wednesday, giving us showers and thunderstorms Tues night.
The weekend looks better than this past one: summer heat and humidity on Saturday, late thunderstorms and gradual cooling and clearing on Sunday.
posted: Jul 24 2006 at 6:56 am
[/weather/jun06] permanent link
Sun, 23 Jul 2006An Email to a Weatherguy Follower...
Someone wrote to me about the forecasts this weekend...here is my reply:
The models have done terribly with this weekend's weather. They over-predicted the precipitation yesterday, especially in Philly. The front was supposed to be off shore this morning, but it's not...it's still in central NJ and the upper air front is still over Philly. Yesterday turned out much better, here at the shore, than previously expected.
I wasn't too confident about either model solution if you recall (in previous private email)......50 mile error in frontal position can be a major difference. And there were more errors than just position of the front...all the dynamics were off.
Last night's WRF has heavy showers this afternoon here at the shore...while the 2 AM rerun (06 UT) has it offshore. Your guess is as good as mine.
Usually the weather is much more deterministic...not this current weekend.
posted: Jul 23 2006 at 6:34 am
[/weather/jun06] permanent link
Sunday Forecast Change- Sun AM
The front has hung up a bit closer to us than previously expected. (It was supposed to be off the coastline by now.) The surface front currently lies somewhere in the middle of New Jersey, while the frontal boundary higher up in the atmosphere is lagging back over Philadelphia. What a bummer!
The upper winds are still from the SW, bringing more moisture over us. Some sun possible, but more clouds will linger today than previously expected and the chance of showers will remain with us as well for much of the morning into early afternoon. High today: 76 with dewpoints lower in the mid 60s. For the Shore: Some sun, but then becoming cloudy with showers possible throughout much of the day. Additional thundershower showers in the afternoon may be heavy. High 79.
posted: Jul 23 2006 at 5:55 am
[/weather/jun06] permanent link
Sat, 22 Jul 2006Sunday Forecast
The rain is over in Philadelphia later tonight, as the front is moving through. A mix of clouds and sun for Sunday as drier air moves in. For the shore, rain and clouds will linger into the late morning. Some sun mid-day, then, there's a chance of additional shower/thunderstorms later in the afternoon, especially south and east.
posted: Jul 22 2006 at 9:25 pm
[/weather/jun06] permanent link
Weekend Forecast- Saturday AM
An extremely moist and unstable atmosphere has developed over us as a frontal boundary is moving slowly in from the west. (Significant thunderstorms have already developed in NJ, at the shore, and are moving NNE, keeping Philadelphia and areas west relatively dry at this point.) Some breaks of sun to the west of Philadelphia will only add to the instability, and areas of major thunderstorms are still expected to form between 12 and 2PM today and then through much of the afternoon. If enough sun breaks out west of Philly, severe thunderstorms, possibly with tornados, are possible.
The WRF continues to forecast the front off the coast by Sunday morning, allowing clearing in Philadelphia and more delayed clearing at the shore. The upper air disturbance will still be over us, so a late afternoon scattered shower in some areas still possible.
Sat 7/22: Mostly cloudy with thundershowers/storms by early afternoon in most areas. Breezy. Humid. High 83. Shore: showers and thunderstorms throughout the day. High 82. Windy.
Sun 7/23: Clouds should give way to some sun.... High 80. Still a chance of a scattered shower late afternoon, but not a sure thing. Shore: Clouds and showers in the early morning...considerable cloudiness and slower clearing. High 79.
posted: Jul 22 2006 at 6:25 am
[/weather/jun06] permanent link
Fri, 21 Jul 2006Weekend Forecast- Friday Afternoon
Still trying to pin down this weekend's weather. Latest WRF model has a more optimistic forecast for Sunday, with the front moving off the coast by early morning.
For Saturday, much of the morning should be dry in most areas... (actually, there's a chance of showers at any time, but trying to nail down a definite forecast here)....showers begin popping up between 11 AM and 2 PM and should continue heavy in most spots around Philadelphia for the afternoon and evening. The front clears the coast early Sunday....sun should break out during the day and much of the day dry.
Sat 7/22: Mostly cloudy with rain by early afternoon in most areas. Humid. High 85. Shore: strong breeze off the ocean, cloudy with some sunny breaks...showers in the afternoon.
Sun 7/23: Clouds should give way to some sun.... High 86. Still a chance of a scattered shower late afternoon. Shore: Showers in the morning...gradual clearing in the afternoon.
posted: Jul 21 2006 at 4:29 pm
[/weather/jun06] permanent link
Weekend Forecast- Friday AM
Trying to do the impossible...pin down the timing and location of the showers expected for this weekend based on the expected position of the stalled front:
Here's my latest guesstimate, based on several versions of the GFS and WRF models: Saturday should be drier than previously expected in Philadephia, with rain holding off until later in the afternoon. (At the shore, showers, especially AC to Cape May on Saturday during the day.) For Sunday rain clears out late morning and partial clearing in the afternoon in Philadelphia. Rain lingers at the shore.
Sat 7/22: A mixture of sun and clouds. Rain late in the afternoon. High 86. Shore: More clouds and showers at the shore during the day.
Sun 7/23: Cloudy with showers in the morning. Partial clearing later in the day. High 83. Shore: Showers linger longer into the afternoon.
posted: Jul 21 2006 at 5:07 am
[/weather/jun06] permanent link
Thu, 20 Jul 2006Wet Weekend Forecast...Updated Thurs AM
The weekend continues to look less than optimum, with the latest GFS model keeping showers in our area through much of Sunday.
Details are likely to change by Friday, but the chance of showers seems to be there all day, with the heaviest precip now on Sunday. It's too soon to assess sky cover or whether we'll see any breaks of sun right now.
Sat 7/22: Considerable cloudiness...a chance of rain/showers during the day. High 82. Similar at the shore.
Sun 7/23: Cloudy with rain/showers. High 82. Similar at the shore.
posted: Jul 20 2006 at 6:19 am
[/weather/jun06] permanent link
Wed, 19 Jul 2006Wet Weekend Forecast...Updated Wed PM
Keeping in my mind that the models haven't been too consistent, it seems that a very unsettled weather pattern is in store for much of Saturday and part of Sunday.
A deep (for summer) upper air trough is expected to form over the middle of the country. We'll be in a moist boundary flow on the east of this trough, with areas of rain developing along this boundary. Tropical moisture may also become entrained in the flow.
Sat 7/22: Considerable cloudiness...a chance of rain/showers during the day. High 82. Similar at the shore.
Sun 7/23: Following early showers, some clearing and sun in the afternoon. High 80s. Similar at the shore.
posted: Jul 19 2006 at 6:45 pm
[/weather/jun06] permanent link
Showers on the Weekend?? Updated Wed AM
The front that caused the thunderstorms last night is stalled just south of Philadelphia and may cause additional showers and thunderstorms today, especially south and east.
There remain model differences and inconsistencies regarding the position of this frontal boundary over the weekend, but the general pattern is for disturbances to ride along the front causing clouds and showers.
The current trend is that there will be afternoon thundershowers on Saturday and that Sunday will be mostly cloudy with showers/rain possible.
Uncertainty about this forecast period remains...look for changes in the forecast each day.
posted: Jul 19 2006 at 5:20 am
[/weather/jun06] permanent link
Tue, 18 Jul 2006Weather Update- Uncertain Period Ahead- Tues PM
The thunderstorms remained fired up, even through Philadelphia this evening. Still much uncertainty in the upcoming forecast period.....
For the short range, the models are showing showers and thunderstorms redeveloping on Wednesday, mid day. Temperatures will be lower, as some cooler air is coming in behind this stalling front.
The latter part of the week and weekend still has a very uncertain forecast....the GFS model has already changed to include a chance of showers on Sunday.
There's a tropical system off the coast that needs watching. Additionally, there's much uncertainty about the position of the stalled frontal boundary for the balance of the week. Expect changes in the forecast each day. I think the best we can do is a 24-36 hour forecast for the time being.
posted: Jul 18 2006 at 7:19 pm
[/weather/jun06] permanent link
Inconsistent Model Forecasts- Tues AM
I've noticed that in the past week, the model forecasts have been inconsistent and not too accurate...examples of this were the thunderstorms on Saturday and the temperature forecast for yesterday. The actual temperatures were a category below the forecast levels.
Tonight's and Wednesday's weather is another example of last minute changes in the models. A front will pass through sometime late evening, bring with it showers and thunderstorms. The WRF has the heavier activity fading out around Philadelphia tonight. Much of it disappears as it gets into Jersey.
The latest change is that this front is now forecast to hang up a bit just south of us tonight. Showers and thunderstorms may redevelop late tonight and linger into Wednesday afternoon. This is a significant forecast change, where several days ago, no showers or rain was forecast here for much of the week.
With all of these shore range changes, any forecast for the weekend weather is very low confidence. There is uncertainty about how far the front will drop. We'll have to see where this frontal boundary actually ends up before attempting an extended forecast for the weekend.
posted: Jul 18 2006 at 7:25 am
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Mon, 17 Jul 2006Weather Update- Heat Wave Shortened- Monday PM
The temperatures didn't get as high as had been predicted by all three models. I believe our high temp was 96 for today, significantly less than the predicted 101. It was still hot!
A front will move through Tuesday night and bring an end to the short heat wave that we've had. This front is expected to cause thundershowers Tuesday evening.
Stay cool!...the temps should fall back to the upper 80s by Wednesday. The weekend still looks good right now, but there will be low pressure systems developing along the frontal boundary that's currently supposed to stay to our south. A change in frontal location will change the forecast.
posted: Jul 17 2006 at 6:35 pm
[/weather/jun06] permanent link
Heat Wave Update- Monday AM
Temperatures are expected to get to 101 today, according to the GFS, NAM and NGM MOS (Model Output Statistics). It's rare to have all 3 model output statistic sets with the same high temp.
An experimental form of the GFS MOS has the temp only hitting 99. Not much of a difference, except the psychological impact of hitting triple digits. It's pretty hot either way. On the positive side, the dewpoints are only expected to be in the mid to upper 60s, which could be much worse.
Stay cool!...the temps should fall back to the upper 80s/90 by Wednesday. The weekend looks good right now.
posted: Jul 17 2006 at 6:23 am
[/weather/jun06] permanent link
Sun, 16 Jul 2006Heat Wave
High pressure in the middle of the country will move over us, bringing extremely hot and humid conditions at least through Tuesday.
Model output statistics have our temperatures between 93 and 95 today and between 98 and 101 for Monday. Dewpoints during the day will be in the high 60s.
Sun 5/16: Mostly sunny, hot and humid. High 93-95. Dewpoints 68-70. Similar at the shore, just a few degrees cooler.
posted: Jul 16 2006 at 5:48 am
[/weather/jun06] permanent link
Sat, 15 Jul 2006Weather Update- Change in Forecast Sat AM
Last night's GFS and some versions of the WRF have showers developing in Philadelphia mid-afternoon, as a weak upper air disturbance moves through. Dewpoints will be high, but temps will only get to the mid 80s.
The models, despite these recent short range changes, continue to advertise a heat wave for Monday through Friday, with GFS temps predicted at 101 for Tuesday!
Sat 5/15: Considerable cloudiness. A chance of showers in the afternoon. High 86. Dewpoints near 70. At the shore: SE flow off the water. Humid and a bit cooler.
Sun 5/16: Mostly sunny, hot and humid. High 90. Dewpoints near 70 or higher.
posted: Jul 15 2006 at 6:09 am
[/weather/jun06] permanent link
Fri, 14 Jul 2006Weather Update- Heat Delayed Fri PM
A big change for tomorrow, Saturday, as some clouds and an easterly flow may keep temperatures in the mid 80s instead of the previously expected 90s. Dewpoints will still be high.
>
Sat 5/15: Some cloudiness, hot and humid. High near 84. Dewpoints near 70 or higher.
Sun 5/16: Mostly sunny, hot and humid. High 90. Dewpoints near 70 or higher.
posted: Jul 14 2006 at 4:54 pm
[/weather/jun06] permanent link
Weather Update- Heat Wave- Friday
The models continue with an upgrade of temperatures for the next 7 days. The GFS model output statistics has a 100 degree temperature for Philadelphia on Monday!
An entrenched and building Bermuada high will develop, bringing hot, steamy weather for our area. Dry conditions expected as upper air support for thunderstorms won't be there.
Sat 5/15: Some cloudiness, hot and humid. High near 90. Dewpoints near 70 or higher.
Sun 5/16: Mostly sunny, hot and humid. High 95. Dewpoints near 70 or higher.
posted: Jul 14 2006 at 5:23 am
[/weather/jun06] permanent link
Thu, 13 Jul 2006Weather Update- Thursday PM
Again, the WRF model correctly predicted that most of the thunderstorms would stay to our south this afternoon and evening.
The frontal boundary that moved through earlier today has reduced dewpoints to the upper 60s instead of the 70s, making things feel a bit more comfortable.
The frontal boundary is now to our south and should remain there over the weekend. Hot and increasingly humid weather will be with us for the next week. A Bermuda high becomes entrenched next week.... very hot, humid and dry weather will be with us through the foreseable future.
Sat 5/14: Sunny, hot and humid. High near 90. Dewpoints near 70 or higher. At the shore: a flow off the ocean should keep things cooler.
Sun 5/15: Mostly sunny, hot and humid. High 93. Dewpoints near 70 or higher.
posted: Jul 13 2006 at 7:28 pm
[/weather/jun06] permanent link
Wed, 12 Jul 2006Weather Update- Wednesday PM
Most of the heavier activity tonight is staying to our north, as predicted by the WRF.
For Thursday, the WRF has more thunderstorms breaking out, but with much of the activity in areas just south of Philadelphia and further south and east. Philadephia proper may miss the heavy activity again tomorrow.
The upcoming weekend still looks good at this point. Hot, hazy, humid summer weather, fair skies. Highs in the low 90s each day.
posted: Jul 12 2006 at 8:52 pm
[/weather/jun06] permanent link
Weather Update- Wednesday AM Revised
With each nightly model run, the chance of thunderstorms in Philadelphia for following day has diminished somewhat. The same is true of last night's model run, which keeps most of the thunderstorms again to our north today, Wednesday. As has beeen the case each day, the models hint at more numerous thunderstorms for the following day, Thursday.
That said, some thunderstorms here in Philadelphia are still possible in such heated soupy air. That was what developed last night in upper Montgomery county. More widespread thunderstorms are now predicted on Thursday afternoon and evening as a weak frontal boundary drops through our area.
The upcoming weekend still looks good at this point. Hot, hazy, humid summer weather, fair skies. Highs in the low 90s each day.
posted: Jul 12 2006 at 7:04 am
[/weather/jun06] permanent link
Weather Update- Wednesday AM
With each nightly model run, the chance of thunderstorms in Philadelphia for following day has diminished. The same is true of last night's model run, which keeps most, if not all, of the thunderstorms again to our north today, Wednesday. As has beeen the case each day, the models hint at more numerous thunderstorms for the following day, Thursday.
That said, isolated thunderstorms are always possible in such heated soupy air. That was what developed last night in upper Montgomery county. More widespread thunderstorms are now predicted on Thursday afternoon and evening as a weak frontal boundary drops through our area.
The upcoming weekend still looks good at this point. Hot, hazy, humid summer weather, fair skies. Highs in the low 90s each day.
posted: Jul 12 2006 at 6:04 am
[/weather/jun06] permanent link
Tue, 11 Jul 2006Weather Update- Tuesday PM
Highly unstable air (high humidty, high 'convective potential energy' and strong vertical lift just west of Philadelphia this evening is causing some thunderstorms to develop. Areas south and east of the city may not see much.
More widespread thunderstorms are predicted on Wednesday afternoon and evening as a low pressure system moves along a frontal boundary just to our north.
The upcoming weekend still looks good at this point. Warm to hot summer weather, fair skies.
posted: Jul 11 2006 at 4:56 pm
[/weather/jun06] permanent link
Weather Update- Tuesday AM
Scattered thunderstorms today, as a weak frontal boundary in northwestern Pennsylvania serves as a focal point for showers to develop.
Last night's WRF shows most of the showers today far north and west of Philadelphia, but does show a bit of scattered activity in Philadelphia. The heavy activity remains far to our north. POP values are not high, so there's a good bet that most areas in our neck of the woods will miss the showers.
The upcoming weekend still looks good at this point. Typical summer weather, fair skies.
posted: Jul 11 2006 at 5:49 am
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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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