Weekend Weather Forecast- Thurs AM
Heavy rains are predicted for Friday. High pressure builds in for the weekend. No snow in sight.
Sat 2/2: Mostly sunny. High 48.
Sun 1/27: Mostly sunny, some clouds in the afternoon. High 48.
posted: Jan 31 2008 at 7:53 am
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Week Weather Outlook- Mon PM
No snow in sight for the coming week. Rain on Tuesday night and again on Friday.
At this time, the weekend looks tranquil with near normal temps and sunshine.
posted: Jan 28 2008 at 9:11 pm
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Week Weather Outlook- Sun PM
Even more sun than had been forecast today. So much for model reliability this winter. Still a nice day for the end of January with virtually no snow on the ground.
The ingredients for a true winter storm remain elusive for us, according to the GFS model. A front and associated low pressure system moves through late Tuesday with rain. Cold weather for Wed and Thursday and then more rain for late Thursday into Friday. The configuration of the jet stream and the storm track just isn't setting up any snow for us. The first opportunity is sometime towards the end of the first week in February.
Cold clear weather for the upcoming weekend. At least that's what the models are showing today.
posted: Jan 27 2008 at 5:07 pm
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Winter Weekend Outlook- Sun AM
Cloud cover today wasn't accurately captured by the models today (or yesterday for that matter), as low pressure did develop off of the coast but we're trapped in the sinking air (subsidence) between two systems, the coastal low and a weak warm frontal boundary in western PA
Some cloudiness at times, but from satellite imagery, we'll have a good deal of sun too today. Temperatures will be warmer than thought with the sun.
Unless this stalled coastal low retrogrades west, not much happening until another system approaches late Tuesday.
Sun 1/27: A mix of clouds and sun. High 44.
posted: Jan 27 2008 at 9:33 am
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Winter Weekend Outlook- Friday PM
High pressure departs tonight as low pressure develops and moves off the coast Saturday night through Sunday. The models keep most if not all of the precipitation with this system east of us, with just some light snow showers Saturday night.
The models have been doing pretty good with predicting the western extent of the precipitation shield, so we'll go with the current model forecast.
There isn't much cold air that will move in behind this coastal storm, in fact, warm air will lift over a cold air wedge; a warm front pattern will develop on Sunday. Somewhat milder temps are expected for Monday and Tuesday.
It currently looks as though January will end here with little or no snow. A storm next Friday will be watched. The first two weeks of February are notorious for storms in this area, even in years where little or no snow has fallen in the prior months.
Sat 1/26: Significant cloudiness, although some bright spots possible. Chance of snow showers at night. High 37
Sun 1/27: Mostly cloudy. Windy in the afternoon. High 41.
posted: Jan 25 2008 at 6:36 pm
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Flurries -Thurs AM
Last night models have reduced the QPF values (water falling) significantly. The NAM is now only 0.01 inches and the GFS is 0.06 inches water. This is down to a snow flurry for today, as low pressure develops along the coastline of VA.
Somewhat warmer temperatures return the latter part of the weekend. As a warm front moves over us Saturday night, there's another chance for very light snow. More on the weekend in coming forecasts.
posted: Jan 24 2008 at 7:13 am
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Here we try again- Wed PM
The GFS has joined the NAM in having some light snow or snow showers Thursday afternoon. Total QPF values about 0.05-0.08 inches water or a coating to as much as an inch. This has been a tough winter to get this right. Temperatures support snow at all levels.
posted: Jan 23 2008 at 4:59 pm
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Nothing again- Wed AM
The NAM has joined the GFS with no snow for Thursday. Had a feeling this would happen.
posted: Jan 23 2008 at 7:11 am
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Snow for Thursday afternoon or maybe nothing again- Tues PM
Surface temperatures above freezing (35 F) kept things all rain in most of this area. I don't think we saw any snow around here today.
Interesting development with the latest NAM model that just became available. It shows all snow (temperatures cold) for Thursday afternoon. The NAM cranks out about .35 inches water which, if it happens, would be 3-5 inches. The GFS model keeps things developing ffar off the coast.
That said, this season has been incredibly difficult to predict. The models haven't been consistent either short term or long term. Even next week, which was originally supposed to be very cold, has changed in outlook, as moderating temperatures (40-50) and rain is predicted for Monday by the GFS. The extreme cold originally predicted to last through the beginning of February has already vanished. Given the way things have been, I'm sure things will change and I'll be retracting the snow forecast for Thursday as well. Stay tuned.
posted: Jan 22 2008 at 11:05 pm
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Update - Monday PM [2]
The latest NAM has less precip falling tomorrow, between 1 and 7 PM. QPF values 0.15 inches water. Wet snow to mostly rain. Little accumulation in the city and immediate suburbs.
posted: Jan 21 2008 at 10:09 pm
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Wet snow for Tues?- Monday PM
As high pressure moves off Tuesday morning, low pressure approaches from the west and blossoms as it nears the coastline. Precip starts Tuesday afternoon into the evening. It will likely start as snow, but will also likely not accumulate much.
Temperatures will be critical with this storm. Upper air temperatures support snow for the beginning of the storm, but surface temperatures will be above freezing and are expected to rise towards evening, both on the ground and at 2000 feet. So any snow will mix with and likely become mostly rain.
So, once again, we'll be in snow--> wet snow/rain line situation, with areas to the north and west possibly getting some accumulation. Current QPF values from the NAM and GFS are about 0.25 inches water. If all snow, this would be 2-3 inches, but a 1 inch slushy coating or less is what to expect.
posted: Jan 21 2008 at 7:30 pm
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Week Weather Outlook- Sun PM
As high pressure moves off Tuesday morning, low pressure approaches from the west and blossoms as it nears the coastline. Precip starts Tuesday afternoon into the evening.
Temperatures will be critical with this storm. Upper air temperatures support snow for the beginning of the storm, but surface temperatures look like they wil be above freezing and remain that way. Additionally temps about 5000 feet will be slightly above freezing.
So, once again, we'll be in snow--> sleet/rain line situation, with areas to the north and west possibly getting some accumulation. Latest NAM model output cranks out over 0.5 inches water for PHL airport, so this low pressure has potential for a messy commute late Tuesday afternoon.
posted: Jan 20 2008 at 10:32 pm
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Winter Weekend Forecast- Sun AM
A winter pattern will be with us for the next two weeks. While there will be moderating temperatures every 3-4 days, the overall pattern is an eastern upper trough and cold high pressure
The current configuration doesn't allow much cyclonic development near us, with most development occuring east in the Atlantic.
While the current outlook is cold and dry, small disturbances will drop through the cold flow, giving us a chance of snow flurries every few days. Mostly quiet....nothing major expected at this time, although changes in the upper trough configuration would make things more interesting.
Sun 1/20: Partly sunny, windy and much colder. High 28.
posted: Jan 20 2008 at 10:13 am
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Winter Weekend Forecast- Sat AM
The overall weather pattern is changing into a deep winter pattern, with very cold air moving in under an overall upper trough.
A polar front will move through late Saturday. Windy conditions and very cold air will move in late Saturday night as a low pressure system passes far off to our east.
The upper air trough remains with us through the next two weeks. Cold weather is in store with the chance of light snow on Tuesday night and again later in the week. Slight change in configuration of the upper trough may allow more storminess to affect us.
Sat 1/19: Considerable cloudiness. Chance of a snow flurry late afternoon or evening. High 40. Severe cold weather and wind moves in after midnight tonight.
Sun 1/20: Partly sunny, very windy and much colder. High 28.
posted: Jan 19 2008 at 7:53 am
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Winter Weekend Outlook- Friday PM
The overall weather pattern is changing into a deep winter pattern, with very cold air moving in under an overall upper trough.
A polar front will move through late Saturday. Windy conditions and very cold air will move in Saturday night as a low pressure system passes far off to our east.
Sat 1/19: Considerable cloudiness. High 40.
Sun 1/20: Partly sunny very windy and much colder. High 28.
posted: Jan 18 2008 at 10:49 pm
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Winter Weekend Outlook- Friday AM
As the pattern changes on Friday to a deep of winter pattern here, (very cold weather and some storminess), the models are having some difficulty with the final configuration.
The coastal low that is expected to develop in the southwest was orginally supposed to pass us to our east on Saturday. Last night's models keep the storm to our east again.
A Polar front will move through on Saturday afternoon. Windy conditions and very cold air will move in, along with some snow flurries.
Sat 1/19: Mostly cloudy. Some snow flurries possible in the afternoon. High 40.
Sun 1/20: Partly sunny very windy and much colder. High 25.
posted: Jan 18 2008 at 7:09 am
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Winter Weekend Outlook- Thurs PM
As the pattern changes on Friday to a deep of winter pattern here, (very cold weather and some storminess), the models are having some difficulty with the final configuration.
The coastal low that is expected to develop in the southwest was orginally supposed to pass us to our east on Saturday. Latest computer models has the storm brushing our area, with as much as 2 inches of snow during the afternoon on Saturday.
Slight change in timing or path could affect this accumulation, but it looks likely that this will be all snow.
Sat 1/19: Mostly cloudy with some snow developing in the afternoon. Accumulations about 2 inches, estimated at this time, although amounts could change. Cold High 34.
Sun 1/20: Partly sunny windy and much colder. High 25.
posted: Jan 17 2008 at 3:37 pm
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Winter Weather Outlook- Wed AM
A change of weather pattern is occurring this week, with a true winter-like January weather pattern moving in over the weekend. This cold weather pattern will last until the end of January, according to the current models. Temperatures will average below normal for the period.
Once this cold air gets entrenched, the upper trough will favor the development of coastal low pressure systems. Nothing major suggested until the last week in January, which promises to become very stormy.
For the short term, the next low pressure system will move up late Thursday into Friday. Mostly rain is expected as warm air moves in with the low.
After Friday, the upper air pattern will allow development of Alberta Clipper systems. Cold and windy weather with some light snow possible for Saturday.
Sat 1/119: Partly sunny...windy cold. Some flurries/snow showers late. High 38
Sun 1/20: Partly sunny windy and much colder. High 28.
posted: Jan 16 2008 at 7:42 am
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Winter Weather Outlook- Tues PM
A change of weather pattern is occurring this week, with a true winter-like January weather pattern moving in over the weekend. This cold weather pattern will last until the end of January, according to the current models. Temperatures will average below normal for the period.
Once this cold air gets entrenched, the upper trough will favor the development of coastal low pressure systems. Nothing major suggested until the last week in January, which promises to become very stormy.
For the short term, the next low pressure system will move up late Thursday into Friday. Mostly rain is expected as warm air moves in with the low.
After Friday, the upper air pattern will allow development of Alberta Clipper systems. Cold and windy weather with some light snow possible for Saturday.
posted: Jan 15 2008 at 7:52 pm
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Storm Postmortem - Monday
As I had said, the temperature profiles of this storm didn't look right (I hadn't seen that sort of verical profile before, admitted Saturday night.), with temperatures aloft being so cold and temperatures on the ground being so warm.
It appears that the models weren't correct about the temperatures aloft being so cold. So not only didn't we get snow accumulating due to warm ground temps, there wasn't cold air aloft to create even wet snow falling.
Apparently, the low pressure system in the Great Lakes didn't transfer enough energy to the coastal low to allow cold air from the northwest to come in. Live and learn.
There's another storm forecast for Thursday night into Friday. It already looks like it will change to rain.
posted: Jan 14 2008 at 7:12 am
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Storm Update - Sun Late Afternoon
Temperatures are as high at ground level as predicted by the models. The freezing line was well into NY State, with 40s extending into the Poconos.
Here are the trends as of 5PM
Latest NAM model (1 PM run) has temperatures higher.
Amount of precipitation falling (QPF values) has fallen to about to about 0.50 inches water.
The precipitation reached us as expected. The storm is a rapid mover.
There's little to no really cold air.
This looks like a mostly rain event now, with wet snow mixing in after midnight, but little accumulation expected in Philadelphia or the immediate suburbs.
The MOS (model output statistics) doesn't predict a changeover to snow until the early morning hours.
posted: Jan 13 2008 at 6:32 pm
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Storm Update - Sun AM [2]
The models are still showing temps above freezing in the immediate Philadelphia area for Sunday evening and night. So it might fall as wet snow as the evening progresses. Predicting accumulations in this scenario isn't really possible, but if the models are correct about the surface temps, this won't be much of a storm, except a 1 -2 inch layer of wet snow
Here are the trends as of 11AM
Upper atmosphere temps are remaining cold enough to support snow, BUT ground temps remain above freezing.
Amount of precipitation falling (QPF values) has fallen to about 0.6 inches water.
The precip will likely reach us between 5 and 7 PM. The storm is a rapid mover.
Less precipitation means dynamic cooling less likely.
Sun 1/13: Some sun early, becoming cloudy early afternoon. Precipitation begins as rain or rain mixed with snow about 5-7PM. Likely becoming all very wet snow later. According to the models, the best guess is an 1-2 inch accumulation in Philadelphia more in the far north and northwest. High 47.
posted: Jan 13 2008 at 11:59 am
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Storm Update - Sun AM
The models are still showing temps above freezing in the immediate Philadelphia area for Sunday evening and night. The statistical models also show less than a 40% chance of snow for the immediate PHL area as well, with probabilities increasing near Allentown. Significant snow is possible in the far northern areas. That said, the temperatures above 2000 feet support snow. So it might fall as snow and then melt or mix with rain in the lower part of the atmosphere. Predicting accumulations in this scenario isn't really possible, but if the models are correct about the surface temps, this won't be much of a storm, except for the heavy rain mixed with snow.
Here are the trends as of 7AM
Upper atmosphere temps are remaining cold enough to support snow, BUT ground temps above freezing.
Amount of precipitation falling (QPF values) are as high as over 1.0 inches water, according to the GFS. The NAM has joined the GFS with about 1.0 inches of water.
The precip will likely reach us between 5 and 7 PM. The storm is a rapid mover.
Extremely heavy precip falls in a six hour period --Most of the precipitation falls before 1AM. Will dynamic cooling bring temps down lower than predicted by the models? Don't know.
The storm depends on a transfer of energy between a low in the Great Lakes and a developing low, a situation often missed by the models. There is no 'large cold high' expected to move in behind the coastal low.
This storm is the toughest one in awhile for me to predict: the temperature profile predicted by the models of this storm is different than most other coastal storms. If the models are correct, this is going to be a mostly rain to snow with just an inch or two accumulating in Philadelphia. (more north and west). If the models are overestimating the ground temperatures (which they might be doing) we could be clobbered. I never try to outguess the models...
Sun 1/13: Some sun early, becoming cloudy late morning. Precipitation begins as rain or rain mixed with snow about 5-7PM. Likely becoming all very wet snow later. According to the models, the best guess is an inch or two accumulation in Philadelphia. If the models are wrong about temps, we could be clobbered with much more. High 43.
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posted: Jan 13 2008 at 8:25 am
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Storm Update - Sat 11 PM
The models are still showing temps above freezing in the immediate Philadelphia area for Sunday evening and night. The statistical models also show less than a 40% chance of snow for the immediate PHL area as well, with probabilities increasing near Allentown. Significant snow is possible in the far northern areas. That said, the temperatures above 2000 feet support snow. So it might fall as snow and then melt or mix with rain in the lower part of the atmosphere. Predicting accumulations in this scenario isn't really possible, but if the models are correct about the surface temps, this won't be much of a storm, except for the heavy rain mixed with snow.
Here are the trends as of 11 PM:
Upper atmosphere temps are remaining cold enough to support snow, BUT ground temps above freezing.
Amount of precipitation falling (QPF values) are as high as over 1.0 inches water, according to the GFS. The NAM has joined the GFS with about 1.0 inches of water.
The precip will likely reach us between 5 and 7 PM. The storm is a rapid mover.
With precipitation rates so high between 7PM and 1AM, will dynamic cooling bring temps down enough to have snow here? Don't know.
Let me say that with all the years I've been looking at snow storms, this is the first time I can remember where temperatures aloft are so low , precip rates so high, and the ground temperatures expected to be several degrees above freezing. I'll be the first to say that I don't have much confidence in calling this storm.
The storm also depends on a transfer of energy between a low in the Great Lakes and a developing low, a situation often missed by the models. There is no 'large cold high' expected to move in behind the coastal low.
Sun 1/13: Some sun early, becoming cloudy late morning. Precipitation begins as rain or rain mixed with snow about 5-7PM. Likely becoming very wet snow, but may not accumulate. Accumulations not able to be determined High 47.
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posted: Jan 12 2008 at 11:06 pm
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Storm Update - Sat Evening
The models are still showing temps above freezing in the immediate Philadelphia area for Sunday evening and night. The statistical models also show less than a 40% chance of snow for the immediate PHL area as well, with probabilities increasing near Allentown. That said, the temperatures aloft support snow. So it might fall as snow and then melt or mix with rain in the lower part of the atmosphere. Predicting accumulations in this scenario isn't really possible.
Here are the trends:
Upper atmosphere temps are remaining cold. Ground temps above freezing.
Amount of precipitation falling (QPF values) are as high as over 1.0 inches water, according to the GFS. The NAM has about .65 inches
The precip will likely reach us late afternoon or early evening. The storm is a rapid mover.
The models haven't shown great consistency. The storm also depends on a transfer of energy between a low in the Great Lakes and a developing low, a situation often missed by the models (precipitation is sometimes much less than forecast if the energy 'skips' over us.)
Sun 1/13: Some sun early, becoming cloudy late morning. Precipitation begins as rain or rain mixed with snow. Likely becoming wet snow, but may not accumulate. Accumulations not able to be determined High 47.
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posted: Jan 12 2008 at 6:38 pm
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Storm Update- Saturday AM
The latest GFS model is in and it again shows over 1 inch of precipitation for Philadelphia. (The NAM shows less) Temperatures at all levels of the atmosphere support snow, but temperatures at the ground in Philadelphia are 2 degrees above freezing. Needless to say, an error of ground temperature will make a whole world of difference here.
Here are the trends:
Upper atmosphere temps are trending colder, as more cold air aloft is forecast.
The track of the storm is now closer to the coast.
The precip will likely reach us late afternoon. The storm is a rapid mover.
That said, temperatures this morning are running lower than predicted by the models, suggesting temps tomorrow may be off. The GFS overestimates temperatures.
We need to watch this, since small changes will make a big change in the forecast. The precip will definitely change to wet snow in Philadelphia and north and west. Whether we have a winter storm will depend on ground surface temps, which are, at this time, expected to be above freezing.
The models haven't shown great consistency. Look for changes in the forecast.
Sat 1/12: Partly sunny. High 52
Sun 1/13: Some sun early, becoming cloudy late morning. Precipitation begins as wet snow late afternoon. Snow may accumulate during the evening. Accumulation amounts not certain at this time, but several inches possible, even a significant storm. High 47.
posted: Jan 12 2008 at 12:22 pm
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Weekend Weather Forecast- Sat AM
There is still uncertainty with the expected development of the coastal storm on Sunday.
Here are the trends:
Upper atmosphere temps are trending colder, as the storm is expected to track somewhat more easterly.
As a result of the easterly track, less precipitation will reach our area. Despite the track, the major models show a surface maxima of precipitation over our area as energy from a Great Lakes low is transfered to the coastal low.
The precip will likely reach us early evening. The storm is a rapid mover.
That said, temperatures this morning are running lower than predicted by the models, suggesting temps tomorrow may be off.
The models continue to show a low pressure system developing along the coastline. Upper air temperatures will support snow, but the models suggest temperatures at the surface will not be below freezing, although there are trends towards lower temps.
We need to watch this, since small changes will make a big change in the forecast. The precip will definitely change to wet snow in Philadelphia and north and west. Whether we have a winter storm will depend on ground surface temps, which are, at this time, expected to be above freezing.
The models haven't shown great consistency. Look for changes in the forecast. This is NOT a storm that is definite.
Sat 1/12: Partly sunny. High 52
Sun 1/13: Some sun early, becoming cloudy late morning. Precipitation begins as wet snow. Snow may accumulate during the evening. Accumulations not certain at this time, but several inches possible. High 47.
posted: Jan 12 2008 at 8:32 am
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Weekend Weather Forecast- Fri PM [2]
High pressure builds in over the weekend, but the models do not have the temperatures falling very far, in fact, temps remain above normal. This will impact the weather system approaching on Sunday.
10 PM UPDATE: Latest NAM model is suggesting heavy snow again for Sunday night....over 1.2 inches water falling with critical levels of the atmosphere at or below freezing. This potential storm continues to bear watching.
The models continue to show a low pressure system developing along the coastline. Upper air temperatures will support snow, but the models suggest temperatures at the surface will not be below freezing.
We need to watch this, since small changes will make a big change in the forecast. The GFS has gone back to predicting almost 3/4 of an inch of water falling, starting during the later part of the afternoon on Sunday. While starting as rain, the precip will definitely change to wet snow in Philadelphia and north and west. Whether we have a winter storm will depend on ground surface temps, which are, at this time, expected to be above freezing.
The models haven't shown great consistency. Look for changes in the forecast.
Sat 1/12: Partly sunny. High 52
Sun 1/13: Some sun early, becoming cloudy late morning. Rain begins late afternoon, mixing with and changing to wet snow. Snow may accumulate during the evening. High 47.
posted: Jan 11 2008 at 10:14 pm
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Weekend Weather Forecast- Fri PM
High pressure builds in over the weekend, but the models do not have the temperatures falling very far, in fact, temps remain above normal. This will impact the weather system approaching on Sunday.
The models continue to show a low pressure system developing along the coastline. Upper air temperatures will support snow, but the models suggest temperatures at the surface will not be below freezing.
We need to watch this, since small changes will make a big change in the forecast. The GFS has gone back to predicting almost 3/4 of an inch of water falling, starting during the later part of the afternoon on Sunday. While starting as rain, the precip will definitely change to wet snow in Philadelphia and north and west. Whether we have a winter storm will depend on ground surface temps, which are, at this time, expected to be above freezing.
The models haven't shown great consistency. Look for changes in the forecast.
Sat 1/12: Partly sunny. High 52
Sun 1/13: Some sun early, becoming cloudy late morning. Rain begins late afternoon, mixing with and changing to wet snow. Snow may accumulate during the evening. High 47.
posted: Jan 11 2008 at 7:08 pm
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Cancel that Storm- Fri AM
The GFS and NAM models have moved away from their previous development of a strong coastal storm near us. The NOGAPS still has some light snow affecting us Monday morning.
This changing scenario for a winter storm has been a problem with past potential storms this season. Sorry for the false alarms. The forecasts can only be as good as the continuity of the models.
More info later today.
posted: Jan 11 2008 at 5:56 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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