Major Snowstorm (> 10 Inches for at Least 50% of Region) Checklist for February 1, 2007: 50 Mile Radius Around PHL

-Conduciveness Factor for a Major Snowstorm: 1 = poor (0-20%); 2 = fair (20-50%); 3 = good (50-80%) ; 4 = excellent (80 – 100%)-

Rating / Comments/Explanation (BOLD INDICATES CHANGES FROM YESTERDAY)
NAO / 1.5 / Hey, at least it’s not positive prior to the stormbut the character of the neg NAO when it was negative in the past week or so was like it was a neutral NAO anyway.
50-50 Low / 2 / A little too far north. Too close to Greenland. Destroying the marginal neg NAO. Not a classic NAO anyway.
EPO / 4 / Negative EPO in good shape.
PNA / 3 / Positive. I like the ridge. It would work fine if other factors were better aligned.
QBO / 4 / I love the QBO. We are in a transition from neutral to falling. Transition periods are strongly correlated to major snowstorms in PHL. Plus we are in between -10.0 and +10.0. This is good. Good for the rest of the month as well.
Polar Vortex / 2 / Over Hudson Bay. Not great, but not the worst spot. Oh, only if the high was there.
500mb Trough/Vort. Max / 1.5 / Open wave trough that slightly increases in amplitude. Positive to neutral to slightly negative. Vort max near PHL or south of PHL. Curves to NE before reaching the east coast. Does so near I-95 corridor. This is bad.
Surface High Pressure / 1.5 / Off Atlantic Coast.—East of New England. No HP present in SE Canada or Western New England.
Low Level Cold Air / 3 / Low level cold air to start but fades away. Can’t hold on due to wind direction. BUT, this is better than yesterday.
Surface Low Pressure / 1.5 / Forecast to track near or outside of CapeH—less precip but keeps low level cold air a little more in place. Track a little off.
700 mb Low / 1 / Lack of distinct comma-head feature. Energy dispersed.
850 mb Low / 1 / No closed circulation.
Snowstorm Dynamics / 1 / Possible dry slot. Banded snowfall, CSI, gravity waves etc. very unlikely
Local Climatology / 2 / End of January, beginning of February not climo favorable. If it were a few days later it would fit better historically.
Teleconnections / 2 / Neutral NAO, -EPO, +PNA. 2 out of 3
MJO / 2 / Phase 6. Not very strong.
Southeast Ridge / 3 / Not much of one really. Not much of a factor honestly.
Ocean Temperatures / 2.5 / A little above 40 in spots. But the ocean is NOT a major factor due to the wind directions not being SE, E, or NE during storm.
Computer Models / 2 / Fair agreement between NAM and GFS. Not as good as yesterday.
DT’s Weekend Rule / 2 / Thursday-Friday. Not the best but close.
Moon Phases / 3 / Full moon. Interesting data in reference to full and new moon phases and major snowstorms that impact the Northeast.
Glenn Hurricane Schwartz and the 3 Phases of a Snowstorm / 2 / We get the overrunning, the storm snow, and get little or no wrap around snow. But the phases are not maximized.
Miscellaneous (Total Precipitation; Time of Day, etc.) / 2 / Timing is good. Nighttime is always the best! Total Precipitation low though
Average Rating / 2.26 (27.8%) / Widespread 10 Inches Simply NOT Favored due to MULTIPLE factors working against it.