*FEBUARY 19th/20th 2012 SNOW THREAT*

...

My Thinking:

This is still subject to change but I think the Nam/Canadian models are likely too slow but the GFS is likely too fast with the evolution of things. Our in-house high resolution 4km model is very close to the ECMWF at 72 hours with a 1004mb surface low just south of the TX/La border and the key cold front across Indiana/Illinois, not as quick as the 12z NAM. So right now, I go with the ECMWF. Which for many of us may bring a flake or two Sunday afternoon and night but likely not enough to cause problems.

However, we are just now starting to get our players over land where they will be sampled by aircraft and balloons so model swings are still likely. But the consistency of the ECMWF gives it credence and it’s scenario make sense given the setup.

connerconner wrote:I need some meds, I don't think I can take this

snowman72 wrote:All I want to see is some big fat snowflake fall once again, right now I don't even care if it sticks

Since there has been much hoopla (not to mention generally bad information floating around on forums, so noted by Craig Allen and David Tolleris in their discussions on the subject) about a big storm on the East Coast this weekend, I decided to post what I think will be helpful directions about the potential for snow, rain, or nothing along the Interstate 95 corridor between Saturday night and Monday morning.

First of all, I am a firm believer that a major storm WILL hit most of Texas, the Deep South, lower and middle Appalachia, and the Eastern Seaboard. But do NOT be fooled into thinking this is an ALL SNOW event. Rather, the deep subtropical moisture fetch that will boost the incoming disturbance (over the Four Corners now) will imply a FURTHER NORTH and MORE INTENSE path than what many of the computer models are showing now. The much-maligned standard GFS is probably too far north and west, but its ensemble members as well as the UKMET and European variants are probably close to the truth. I am saying Galveston TX....Macon GA....Norfolk VA....200 mi SE Nantucket MA in a Friday to Monday morning time frame.

Negative tilt systems with well-defined warm/moist advection mechanisms almost always reach 990MB intensity or lower. Because of so much warm advection and no "holding anticyclone" in QC, I suspect that anyone living below Providence RI to Port Jervis NY is going to see a majority rain changeover. But a shift back to snow is entirely possible as far south as the Virginia suburbs of Washington DC as the low gets cranking. If you want a big snow situation, maybe sections of E KY....WV....W VA and W MD might be primed. Operative word is MIGHT....for the rest, a windy, raw ugly storm with -mainly- rain. And I think SE TX gets a good dunking Friday night and Saturday morning.

Toot wrote:990Mb is a pretty stout for an extratropical storm in the eastern US... and I would think it would have plenty of cold advected wrap around precip into middle and east TN.

Toot wrote:Adam the storm hasn't trended north...the gfs has trended north but the euro and cmc are well south of it. So..the gfs is probably too far north...Just sayin

Here is what HPC is taking from all guidance...notice the low is further south than the gfs