Bob Chill Posted January 24, 2011 Share Posted January 24, 2011 It's would be wise to stop focusing on the 2m and thermal profile of every model run. There is no obivious high to our NE to supply us with obvious cold air. A degree or two in any direction will have a large impact on the outcome. The models cannot be expected to have 25-50 mile accuracy of the surface temps and 850's when the source of cold is missing and the temps are marginal. We can follow trends and make general predictions but it will come down to the event unfolding before the big winners and losers are determined. Link to comment Share on other sites More sharing options...
mappy Posted January 24, 2011 Share Posted January 24, 2011 Not today, Jason used a quote. I'll be doing one tomorrow. Wonderful. Looking forward to it. Link to comment Share on other sites More sharing options...
WxUSAF Posted January 24, 2011 Share Posted January 24, 2011 Totally didn't mean it as an IMBY question, that's just the only elevations I know offhand. I am genuinely curious about what kind of elevation change impacts borderline events like this...in the abstract, even, rather than specific to Wednesday. I don't think there's any good rule-of-thumb for how much elevation counts for how much change. It's just safe to say that "higher is better". During a precip event, the lapse rate in the atmosphere (temp change with height) is probably somewhere between 5-6C/kilometer. That works out to be about 0.3F/100 ft. So, if you're 300ft higher, you're about 1F cooler. With borderline temps, that could be a big deal. I just checked the GFS forecast soundings for the storm. Temps are actually pretty uniform in the lowest 500-1000ft. So, maybe even less of an effect than what it could be. Link to comment Share on other sites More sharing options...
Ian Posted January 24, 2011 Share Posted January 24, 2011 i cleaned up this thread--stop the bickering.. thx Link to comment Share on other sites More sharing options...
derecho Posted January 24, 2011 Share Posted January 24, 2011 First call. Link to comment Share on other sites More sharing options...
stormtracker Posted January 24, 2011 Share Posted January 24, 2011 I picked the wrong year to move from HGR Link to comment Share on other sites More sharing options...
Bob Chill Posted January 24, 2011 Share Posted January 24, 2011 Not much to argue about there Derecho. The only thing I see differently would be the potential for 6-10 in Carrol and Frederick counties. Westminster and Mt. Airy may be looking pretty good for 6+. Link to comment Share on other sites More sharing options...
WxUSAF Posted January 24, 2011 Share Posted January 24, 2011 First call. Looks pretty good. I suspect the gradient might go a bit more WSW-ENE though vs being roughly parallel to a DC-Balt line. Mostly due to the higher elevation as you move northwestward from the Bay. Link to comment Share on other sites More sharing options...
WxUSAF Posted January 24, 2011 Share Posted January 24, 2011 Looks like the Euro has a general idea of the DT Facebook Storm #2 out at 216hr+. Looks OTS though with a very progressive pattern. Euro looks very cold and dry in the long range. Still has the nice PNA ridge out west. Weak ridging into Greenland. Link to comment Share on other sites More sharing options...
H2O Posted January 24, 2011 Share Posted January 24, 2011 Looks pretty good. I suspect the gradient might go a bit more WSW-ENE though vs being roughly parallel to a DC-Balt line. Mostly due to the higher elevation as you move northwestward from the Bay. Follow the fall line? Link to comment Share on other sites More sharing options...
WxUSAF Posted January 24, 2011 Share Posted January 24, 2011 Follow the fall line? What's the fall line? Link to comment Share on other sites More sharing options...
yoda Posted January 24, 2011 Share Posted January 24, 2011 Very nice consistency among the 12z GFS ensemble members. They're all a bit faster and a bit farther east than the Op, leading to a colder/snowier solution. Ensemble mean looks to keep areas JUST north/west of I-95 all (or nearly all) frozen. 850mb 0C line looks to stay on or south of the cities for the duration of the precip, it's the surface temps that are the issue. Surface 0C line looks to get as far north/west as a Winchester/Hagerstown line, and then falls back. Thats good to hear. I am sure we can deal with 34 degree wet snow Link to comment Share on other sites More sharing options...
weathercoins Posted January 24, 2011 Share Posted January 24, 2011 LWX update in 45 minutes will be interesting. I wouldn't be surprised to see some of us end up in the watch category.... and the POP to go way up (with still uncertainty regarding rain or snow)... Link to comment Share on other sites More sharing options...
mappy Posted January 24, 2011 Share Posted January 24, 2011 First call. Derecho - I'm assuming that areas who could see 2-4 inches would not be snow the entire time? Rain, rain/snow, then snow at the end? Link to comment Share on other sites More sharing options...
H2O Posted January 24, 2011 Share Posted January 24, 2011 What's the fall line? piedmont into coastal plain Link to comment Share on other sites More sharing options...
weathercoins Posted January 24, 2011 Share Posted January 24, 2011 Derecho - I'm assuming that areas who could see 2-4 inches would not be snow the entire time? Rain, rain/snow, then snow at the end? I don't see how it wouldn't be.... QPF looks possibly huge overall... 1"++? Link to comment Share on other sites More sharing options...
derecho Posted January 24, 2011 Share Posted January 24, 2011 Derecho - I'm assuming that areas who could see 2-4 inches would not be snow the entire time? Rain, rain/snow, then snow at the end? Possibly some rain and warm sfc temps. Right now I would be more concerned about this going ots than too far inland. Link to comment Share on other sites More sharing options...
Herb@MAWS Posted January 24, 2011 Share Posted January 24, 2011 What's the fall line? http://www.globalclassroom.org/geog.html Go to para (1) re: Piedmont Plateau "Most rivers in Maryland can be navigated up to the point where there are waterfalls. An imaginary line connnecting the falls of each river would make the fall line." Link to comment Share on other sites More sharing options...
Huffwx Posted January 24, 2011 Share Posted January 24, 2011 I love where we're sitting back here in SW VA-- My blog has been updated to reflect a call of 4-8 inches. having nothing but a reputation at stake is good-- we have plenty of wiggle room for the late north trend since the ULL low snows start well over 100 miles to my S and SW. (According to the EC) * Noting that the north trend would be more like the NOT DIGGING as deep trend* I suspect if the 0z data falls in line like the GFS/EC for our region, we go under watches tomorrow morning. Link to comment Share on other sites More sharing options...
mappy Posted January 24, 2011 Share Posted January 24, 2011 Possibly some rain and warm sfc temps. Right now I would be more concerned about this going ots than too far inland. Thank you, Derecho. Link to comment Share on other sites More sharing options...
Bob Chill Posted January 24, 2011 Share Posted January 24, 2011 Huff, whats your elevation and what is the verical rise from 75 miles to your east? Link to comment Share on other sites More sharing options...
yoda Posted January 24, 2011 Share Posted January 24, 2011 15z SREFs out to 51 hrs... 0.5 QPF line right now EZF to ACY 2m 32 degree temps WV/VA line 0C 850 just west of Blue Ridge (in a SW/NE fashion... CHO is probably just east of 0C) Link to comment Share on other sites More sharing options...
yoda Posted January 24, 2011 Share Posted January 24, 2011 Closest the 1" QPF comes to us Link to comment Share on other sites More sharing options...
weathercoins Posted January 24, 2011 Share Posted January 24, 2011 How accurate are the SREF's this far out? I would think past 48 not very at all, especially for something that is going to be so localized like this. Link to comment Share on other sites More sharing options...
Huffwx Posted January 24, 2011 Share Posted January 24, 2011 Huff, whats your elevation and what is the verical rise from 75 miles to your east? My house is about 950 ft---75 miles east is 500 feet or so. Link to comment Share on other sites More sharing options...
yoda Posted January 24, 2011 Share Posted January 24, 2011 Pretty much mid 30s for the entire event for temps... then slowly drops as the 2m 32 line falls to the SE . 5C line (40 degrees+) does not get NW of RIC Link to comment Share on other sites More sharing options...
usedtobe Posted January 24, 2011 Share Posted January 24, 2011 How accurate are the SREF's this far out? I would think past 48 not very at all, especially for something that is going to be so localized like this. For qpf it is pretty good. I don't know about temps but they should be better than the gefs ensemble mean. Thye have bettern resolution. Link to comment Share on other sites More sharing options...
PhineasC Posted January 24, 2011 Share Posted January 24, 2011 Pretty much mid 30s for the entire event for temps... then slowly drops as the 2m 32 line falls to the SE . 5C line (40 degrees+) does not get NW of RIC Sounds good. Link to comment Share on other sites More sharing options...
Ian Posted January 24, 2011 Share Posted January 24, 2011 euro ensemble mean basically the same as the op but maybe a hair north with all features.. initially slightly warmer 850 but maybe a little cooler on the back. Link to comment Share on other sites More sharing options...
yoda Posted January 24, 2011 Share Posted January 24, 2011 15z SREF -- 850 0c line Blue Ridge at 54... just east of I-95 hr 57 Link to comment Share on other sites More sharing options...
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