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The Story Behind the Weather - By Forecaster John
Ensworth M.S. -
The Discussion of Weather Events Daily for Philadelphia and Pennsylvania
Last updated: 12/23/2003 11:03 AM
Good Morning Philadelphia!
I'm glad to announce that these
discussions will continue until at least the end of January!
I
have the necessary server space (especially with missed days!).
In short: Partly cloudy
skies will increase to cloudy skies over the next day. Christmas Eve will
see rain, while the rain may switch over to snow by Christmas Night.
Please Note: I'm logging in via dial-up modem from
Corpus Christi, TX where I will be spending the Christmas break.
Due to the slow connection, I'll keep it brief when I can log
on and update this site. I may have to switch to an every-other-day
schedule as I travel.
In long: The Lake Effect snow is all but gone. This snowfall map is the snowfall as of Sunday night 7pm, so it IS all gone now in the city.
In fact, since it has (contrary to how I forecasted it yesterday) cleared out, you can see the remaining snow on the ridge tops in central PA (circled in red).
Temperatures have exploded into the 50's in Philadelphia and it is ONLY 11am!
This warmth is streaming northward on the south winds dominating the eastern US ahead of the next system.
Air flows counterclockwise around Lows in the northern hemisphere (and the opposite in the southern hemisphere) so the flow ahead (to the east of the approaching lows and front) is from the south. This system is quite warm, you can only find a few spits of snow on the back side of the precipitation shield.
So by 1am Wednesday morning, we see the Lows and front progressing further eastward towards us with rain beginning to break out along the coast and near or in Philadelphia.
By Christmas Eve, 7am, rain dominates the whole east coast. Rain rain rain.
By Christmas Eve evening, the rain is, if anything, more widespread and heavy!
The GFS forecast from the pro side of www.Accuweather.com (go subscribe NOW... go NOW! It's GREAT!) shows no snow or snow-like substance in Pennsylvania. Just rain.
We'll have a precipitation-free slot moving into southeastern Pennsylvania...
And air temperatures (as of 1pm Christmas Day) are still above freezing over the eastern half of the state. Sorry, it sure looks like snow is out of the question for Christmas.
In the mean time, get your shopping done and make sure your Christmas decorations are waterproof!
Meteorologist John Ensworth
Surface Station sky cover color key:
Flight category definitions:| Category | Ceiling | Visibility | |
|---|---|---|---|
| Low Instrument Flight Rules LIFR* (magenta circle |
below 500 feet AGL | and/or | less than 1 mile |
| Instrument Flight Rules IFR (red circle) |
500 to below 1,000 feet AGL | and/or | 1 mile to less than 3 miles |
| Marginal Visual Flight Rules MVFR (blue circle) |
1,000 to 3,000 feet AGL | and/or | 3 to 5 miles |
| Visual Flight Rules VFR+ (green circle) |
greater than 3,000 feet AGL | and | greater than 5 miles |
| *By definition, IFR is ceiling less than 1,000 feet
AGL and/or visibility less than 3 miles while LIFR
is a sub-category of IFR. +By definition, VFR is ceiling greater than or equal to 1,000 feet AGL and visibility greater than or equal to 3 miles while MVFR is a sub-category of VFR. |
|||