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Miscellaneous
Wed, 31 Jan 2007
Winter Storm Update- Again- Wed PM
This is going to be one tough storm to predict. Things have gone back and forth. What seemed like a clear cut snow to rain event is more complicated.
The latest NAM and GFS data has just become available. The NAM has the storm missing us to our south.
The GFS now has a more intense storm moving closer, with snow turning to a mix Friday morning. Possibly 3-4 inches possible before a mix with sleet and rain late Friday morning. Areas just to the west of Philadelphia will have a slower changeover. Even more complicated, cold air will come into this region early afternoon on Friday, with the mix changing back to snow.
Frankly, I think nailing the snow amounts with this storm is an impossibility, except to say that it will be anywhere from 1-3 inches and will vary significantly with location.
This all assumes that the GFS is correct. The NAM and old NGM show an almost complete miss for Philadelphia, where the storm will be to our south and east.
I'll try to nail this down tomorrow.
posted: Jan 31 2007 at 11:05 pm
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Winter Storm Update- Change in Forecast
Today's models continued with the trend of last night's NOGAPS model- a greater bulk of cold air will suppress the path of the storm to our south, resulting in less precipitation, especially north and west and greater likelihood of mostly snow for Philadelphia and just north.
This means that for the Philadelphia area, the changeover to rain will be less likely; it will likely be all snow or a slight mix. Areas to the north and west will have much lesser amounts.
Latest GFS models show about .20 to .30 inches of water falling (QPF value) which may translate into 2, maybe 3 inches of snow. Snow will start very light late Thursday afternoon with a bit heavier amounts before daybreak on Friday and will taper off Friday morning, giving a total of 2, maybe 3 inches. Very cold temps will follow over the weekend and next week.
Should the storm intensify more or slow down a bit more, amounts could increase. Or, if more cold air builds in, the precip could be further suppressed to our south. I'll update after 11 PM this evening.
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posted: Jan 31 2007 at 6:04 pm
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Winter Storm Outlook-Wed AM
Here are the changes since my last forecast yesterday:
First, this is not going to be a major storm. There's little phasing of the jet streams and the storm is a fast mover. Total QPF values (water falling in any form) is about 0.10 inches to 0.25 inches water.
All operational models and statistical means from the ensemble models continue to show a change to sleet/freezing rain and rain during the late night hours of Thursday. Atmospheric thickness values do not support all snow, although it will start as snow.
Some trends, especially with the NAVY NOGAPS model, has the storm scooting out to our south almost missing us.
Here's the bottom line -- if the storm continues to hug the coast, the heavier precip will change to rain; if it scoots out to our south, any precip will be quite light and remain as snow. Either way, we're not looking at a major storm, just a lousy commute on Friday morning.
I'll update later tonight.
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posted: Jan 31 2007 at 7:10 am
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Tue, 30 Jan 2007Winter Storm Outlook-Tues AM
A weak Alberta clipper type disturbance will give us some light snow showers tonight.
A coastal nor'easter storm, the first for this winter, will approach Thursday afternoon and bring light snow early Thursday night. Precipitation will become heavier, but atmospheric thickness levels indicate too shallow a column of cold air for snow, so a change to freezing rain and then rain for much of the storm is my prediction for the immediate Philadelphia area. Far northern and western suburbs of Chester Montco and Bucks county will have a greater chance of snow.
The Thursday night storm is still several days off...expect things to change as we get closer.
posted: Jan 30 2007 at 7:10 am
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Mon, 29 Jan 2007Week Weather Outlook- Mon PM
An interesting week coming up, where our first chance at a significant winter storm will be on Thursday night into Friday. Additionally, a very cold pattern will remain with us through next weekend where windy conditions will be prominent on Saturday.
As for this storm expected Thursday evening, Philadelphia will be on the borderline of rain/snow with the current statistical models showing rain/sleet most likely. With ocean water temperatures running so high this season, this borderline pattern that Philadelphia often finds itself in will be slanted towards rain instead of snow.
The Thursday night storm is still several days off...expect things to change as we get closer.
posted: Jan 29 2007 at 7:25 pm
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Sun, 28 Jan 2007Update- Sunday night
The NAM and GFS have come together tonight with about 0.08 inches of water (QPF)falling as snow tonight. This translates into about 1 inch or so.
Temperatures will be dropping considerably. Expect icy conditions in the morning, even with a coating to an inch of snow.
posted: Jan 28 2007 at 11:07 pm
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Update- Sunday Afternoon
Once again, there is low confidence with the forecast, because the GFS and NAM disagree about rain/snow for us this afternon and night and neither correctly captures the precipitation on radar this early afternoon.
The GFS is predicting nothing, while the NAM-WRF is showing about 1 inch of snow tonight. I wouldn't hang my hat on either solution, but the radar trends suggest that the NAM may be underestimating the potential for 1-2 inches and the GFS is certainly missing the boat.
Sun 1/28: Cloudy the balance of the afternoon, with light rain showers possible this afternoon, changing to light snow this evening. Possibly 1 inch of snow potential by Monday morning, although confidence in this forecast is lower than usual.
posted: Jan 28 2007 at 1:33 pm
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Sat, 27 Jan 2007Update- Sat PM
A significant area of precipitation has developed over our area. The latest GFS, just becoming available, clearly has not captured the amounts accurately. The NAM is even more off, since it shows no precipitation at all tonight.
Right now, the temperatures are above freezing and rain is falling. The models are predicting that temperatures will be above freezing tonight. Little or no accumulation is likely if that is the case, although temperatures aloft may allow the precip to change to wet, non-accumulating snow.
Confidence in the forecast tonight is unusually poor, with neither major model accurately depicting what is falling right now.
Sun 1/28: Rain mixing with and changing to wet snow. Little accumulation. Becoming partly cloudy, windy and colder. High 35. Possible light snow again Sunday night.
posted: Jan 27 2007 at 11:41 pm
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Wooops...Light snow back in the Forecast- Sat PM
The warm front didn't make it that far north today. Temps have remained in the high 30s around here.
Another front moves through late tonight into Sunday morning. This morning's GFS model has the same 0.10 inches of QPF falling on or before daybreak on Sunday. This means I'm putting back the 1 inch of light snow for early Sunday morning. The arctic front that moves through Sunday night may cause additional light snow.
Early next week becomes very cold again for the balance of January.
Sat 1/27: A mix of sun and clouds, breezy and milder. High 38-40.
Sun 1/28: Some snow ending around daybreak Sunday morning. Up to 1 or so of snow. Then, partly cloudy, windy and colder. High 35. Possible light snow again Sunday night.
posted: Jan 27 2007 at 3:19 pm
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Weekend Weather Forecast- Sat AM
We'll get into the 40s today.
Another front moves through late tonight into Sunday morning. The weak low pressure that was expected to develop will be too far south to affect us. I'm removing the snow from the forecast on Sunday morning. The arctic front that moves through Sunday night may cause snow showers.
Early next week becomes very cold again for the balance of January.
Sat 1/27: A mix of sun and clouds, breezy and milder. High 45.
Sun 1/28: Partly cloudy, windy and colder. High 36. Possible light snow Sunday night, up to an inch.
posted: Jan 27 2007 at 9:16 am
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Fri, 26 Jan 2007Weekend Weather Forecast- Fri AM
Today will be cold, but the cold air retreats rapidly tomorrow, with the models predicting highs in the 40s.
Another front moves through late Saturday night into Sunday morning. A weak low pressure system is expected to form along the front, likely giving us some light snow Sunday morning. The GFS model has been consistent with this and is showing about 0.10 inches water falling. This could translate into about 1, maybe 2 inches of snow, ending late Sunday morning.
Early next week becomes very cold again for the balance of January. Our first significant snowfall may be coming next Friday.
Sat 1/27: A mix of sun and clouds, breezy and milder. High 43.
Sun 1/28: Chance of light snow early morning. 1-2 inches possible. Becoming partly cloudy windy and colder. High 36.
posted: Jan 26 2007 at 7:25 am
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Thu, 25 Jan 2007Cold Air Arrives - Thurs Late AM
Additional snow showers are being forecast for our area today by the weather service, although the models are not explicit about them.
After a very cold Friday, temperatures moderate on Saturday, before another front moves cold air back in on Sunday.
The details on this weekend have changed a few times over the past few days. The latest NAM model has a possible storm forming along a front as it moves through here Sunday morning. We have to watch for some snow on Sunday morning...details not clear at this time.
Early next week becomes very cold again for the balance of January. No storms affecting us showing at this time, but expect things to change the first days in February.
Sat 1/27: A mix of sun and cloudiness, breezy and cold. High 40.
Sun 1/28: Chance of snow or flurries early. Partly cloudy windy and cold. High 36.
posted: Jan 25 2007 at 11:09 am
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Cold Air Arrives - Thurs AM
Some light snow showers have affected our area (not shown clearly on the GFS model) as very cold air moves in later this afternoon and tonight.
After a very cold Friday, temperatures moderate a bit on Saturday, before another front moves cold air back in on Sunday. Details on the weekend forecast have changed considerably over the past two days.
Early next week becomes very cold again for the balance of January. No storms affecting us showing at this time, but expect things to change the first days in February.
Sat 1/27: Considerable cloudiness, breezy and cold. High 39.
Sun 1/28: Chance of snow flurries early. Partly cloudy windy and cold. High 38.
posted: Jan 25 2007 at 6:57 am
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Wed, 24 Jan 2007Cold Air Arrives - Wed AM
A coastal storm will pass by us to our east, bringing down very cold air. A very cold day for Friday. Some snow showers are possible Thursday night, Friday morning, Saturday morning and Sunday morning as mid-level disturbances rotate through our area.
Very cold air returns for the balance of January. No storms until February.
Sat 1/27: Partly sunny, breezy and cold. High 37.
Sun 1/28: Chance of snow flurries. Mostly cloudy windy and cold. High 36.
posted: Jan 24 2007 at 6:39 am
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Mon, 22 Jan 2007Week Weather Outlook- Mon
The storm on Wed-Thurs now appears delayed and it will move out to sea, missing us. Very cold air will be with us on Friday through Saturday. A modest warm up on Sunday.
posted: Jan 22 2007 at 7:22 am
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Sun, 21 Jan 2007Week Weather Outlook
Very light flurries is falling over PHL at this time. A dusting/coating will likely be all that we get tonight. (latest NAM model has 0.05 inches water).
Continued cold weather for the coming week, with a slight warmup on Wednesday.
A large coastal storm is expected to develop Wednesday night into Thursday. Current models have this storm staying east of our area again, with the vast majority of the snow missing us. We may get some light snow, however. We have to watch this.
The weekend looks cold again.
posted: Jan 21 2007 at 9:39 pm
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Forecast Update- Sunday Afternoon
GFS and NAM models have a total of about 0.10 inches water falling from this evening through dawn on Monday. Atmospheric density and coldness supports this precip falling as light snow. As much as a coating to 1 inch is possible by Monday morning.
posted: Jan 21 2007 at 2:33 pm
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Weekend Weather Forecast- Sun PM
Clouds will increase this afternoon, and the latest GFS has some light snow moving in late this evening, especially south and east of PHL, into the early Monday morning hours.
Amounts will be very light....a coating possible, especially south.
Sun 1/21: Mostly sunny, still breezy. Becoming mostly cloudy in the afternoon. High 36. Chance of a dusting/snow flurries at night.
Long range: Watch Thursday into Friday for VERY cold weather and possible light snow.
posted: Jan 21 2007 at 8:46 am
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Sat, 20 Jan 2007Weekend Weather Forecast- Sat AM
Low pressure will deepend off of the NE coastline and will bring in cold air and windy conditions for today. Another low will miss us, just to our south, on Sunday night and Monday, giving areas from the city and south the chance of a dusting of snow.
A deep trough sets up for next Thursday, with another chance of snow, but right now, most of the heavy precipitation misses us.
Sat 1/20: Some snow showers possible during the morning, then mostly sunny, VERY WINDY, and cold. High 38.
Sun 1/21: Mostly sunny, still breezy. Becoming mostly cloudy in the afternoon. High 36. Chance of a dusting/snow flurries at night.
Long range: Watch Thursday into Friday for VERY cold weather and possible light snow.
posted: Jan 20 2007 at 6:43 am
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Fri, 19 Jan 2007Weekend Weather Forecast- Fri
The low pressure affected us a bit more than predicted yesterday....looking back, the statistical GFS ensemble model did pretty well with slightly more precip that we received.
This storm will deepen off the NE coastline and will bring in cold air and windy conditions for Saturday and Sunday. Another low will miss us, just to our south, on Sunday night and Monday. A deep trough sets up for next Thursday, with another chance of snow, but right now, it misses us as well.
Sat 1/20: Mostly sunny, VERY WINDY, and cold. High 36.
Sun 1/21: Mostly sunny, still breezy. Some increased cloudiness in the afternoon. High 34.
Long range: Watch next Thursday into Friday for VERY cold weather and possible snow.
posted: Jan 19 2007 at 4:47 pm
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Thu, 18 Jan 2007Snow Flurries- Thurs Early PM Update
A quick update..... latest models have between 0.02 and 0.06 inches of water falling this afternoon into early this evening. Atmospheric thickness levels support the precip falling as snow, but temps on the ground will be near or above freezing. Not much if any accumulation...a dusting possible.
posted: Jan 18 2007 at 1:40 pm
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Wed, 17 Jan 2007Snow will miss us- Updated Wed PM
The latest GFS and NAM have the expected cyclogenesis east of the DE coastline for Thursday night into Friday....any snow or flurries will be in NJ with the precip just brushing Philadelphia. Not much of anything expected here...perhaps a few flurries here in the city Thursday evening.
This storm will deepen off the NE coastline and will bring in cold air and windy conditions for Saturday and Sunday.
Sat 1/20: Mostly sunny, VERY WINDY, and cold. High 35.
Sun 1/21: Mostly sunny, still breezy. Still cold. High 34.
Long range outlook: continued cold. Most of the storms expected to develop too far off the coastline. The latest GFS model suggests a real snowstorm for Feb 1-2. Far off to take seriously yet.
posted: Jan 17 2007 at 11:09 pm
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Light Snow for Early Friday?- Updated Wed AM
Expected cyclogenesis off of the DE coastline for Friday....the GFS has very light snow just brushing us before daybreak and early morning on Friday. The GFS statistical ensemble has its mean value slightly west of the regular GFS model, possibly giving us a bit more snow. Amounts will be very light, if any...a dusting to less than an inch.
This first winter snow has a good chance of missing us entirely. Updates later today.
posted: Jan 17 2007 at 8:33 am
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Tue, 16 Jan 2007Week Weather Outlook- Some Snow? -Tues AM
Those of you who read my forecasts know that I've been predicting a pattern change for January 17th since New Years Day.
see my Forecast from New Years Day
The original GFS prediction had a sharp trough with storm development moving up the coastline.
The broader trough that is now predicted will still result in coastal storm development, but these storms will scoot out to sea, instead of moving up along the coastline.
The latest GFS has our first coastal storm possibly affecting us this Friday. A mix of light rain and snow may affect Philadelphia and areas to our east in NJ. We need to watch this. Slight change in configuration of the jet stream could mean more (or no) snow for us on Friday.
The weekend looks windy and cold, fair on Saturday, some clouds on Sunday.
The long range models have a stormy and cold pattern through Jan 31st. Exact configuration of the jetstream will determine our chances of significant snows.
posted: Jan 16 2007 at 7:37 am
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Mon, 15 Jan 2007Week Weather Outlook- Monday
The weather change that has been predicted by the GFS for several weeks will be arriving on schedule by Wednesday, as cold air will become firmly entrenched in our area for the first time this winter.
The GFS has originally predicted a sharp trough with storm development along the coastline. The broader trough that is now predicted will still result in coastal storm development, but these storms will scoot out to sea, instead of moving up along the coastline. This will affect whether Philadelphia will get any snow from these storms. The first of these storms will be this Friday, Jan 19th. We'll have to watch this.
The weekend looks cold.
posted: Jan 15 2007 at 7:32 am
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Sat, 13 Jan 2007Update Sat AM
The models have over-estimated the cloud cover this morning and the showers. This is what gives weather forecasters a bad name. :-)
Sat 1/13: Some sun in the morning, more clouds in the afternoon. Chance of light showers in the afternoon. Mild. High near 60.
Sun 1/14: Cloudy with showers likely, especially in the morning. High 50.
posted: Jan 13 2007 at 9:37 am
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Wet Weekend- Weekend Update - Sat AM
The actual amounts of rain expected over the next two days has decreased significantly with the latest model run. Light showers possible today and Sunday. (The heaviest axis of rain has turned out to be in northern PA....there was uncertainty about the amounts and timing.)
This weekend's somewhat uncertain rain timing preceeds a significant weather pattern change for us next week, as the position of the winter trough will finally be over our area, bringing cold conditions.
Checking the longer range statistical models, there isn't really any snow showing up for the next week or two! The depth and sharpness of the expected winter trough has shallowed significantly from previous model runs.
Sat 1/13: Cloudy with some light showers likely, especially in the afternoon. Mild. High 53
Sun 1/14: Cloudy with showers likely, especially in the morning. High 50.
posted: Jan 13 2007 at 9:14 am
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Fri, 12 Jan 2007Wet Weekend- Weather Pattern Shift - Fri PM
A warm and wet pattern for the next several days, through Tuesday, as low pressure impulses move up along a frontal boundary that will be sagging into our area from the north. Exact timing of these impulses and the showers will be tough.
This weekend's somewhat uncertain rain timing preceeds a significant weather pattern change for us next week, as the position of the winter trough will finally be over our area, bringing cold conditions.
Checking the longer range statistical models, there isn't really any snow showing up for the next week.
Sat 1/13: Cloudy with some showers likely, especially in the afternoon. Mild. High 53
Sun 1/14: Cloudy with showers likely. High 50.
posted: Jan 12 2007 at 11:36 pm
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Wet Weekend- Weather Pattern Shift - Fri AM
A warm and wet pattern for the next several days, through Tuesday, as low pressure impulses move up along a frontal boundary that will be sagging into our area from the north. Exact timing of these impulses and the showers will be tough, but Saturday night through Monday will have the heaviest rain.
Originally, it appeared that Saturday would be a somewhat drier day, but this morning's models have some significant rain/showers for Saturday.
This weekend's somewhat uncertain weather details preceeds a significant weather pattern change for us next week, as the position of the winter trough will finally be over our area, bringing cold conditions. The frontal boundary and storm track will be just offshore over the next week or so, so expect the possibility of storms and even some ice/snow next weekend.
Sat 1/13: Cloudy with some showers and rain likely. Mild. High 53
Sun 1/14: Cloudy, chilly with rain. High 47.
posted: Jan 12 2007 at 8:22 am
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Thu, 11 Jan 2007Weekend Forecast - Thursday PM
Warm air returns to our area, but a southwesterly flow of very moist air will bring clouds and showers. Low pressure impulses will form along a frontal boundary and move over us from Saturday through Monday. Timing of these impulse will be tough, but Sunday and especially Monday will have the heaviest rain.
Sat 1/13: Cloudy with some light showers likely. Not a rain out. Mild. High 53
Sun 1/14: Cloudy, chilly with rain. High 46.
posted: Jan 11 2007 at 6:40 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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