Monday, January 21, 2013

Sunday Evening Technical Discussion

Synopsis:

A cold front has passed through bringing cold weather. The northwesterly flow today will touch off lake-effect snow showers for the morning. Then, a weak low pressure area will slide across the PA-NY border, bringing snow to the entire state for the afternoon & evening, but heavy snow squalls will be confined to areas north of the Turnpike. High pressure (the center of an arctic air-mass) from the Northern plains will slide into the region on Tuesday, bringing another round of lake-effect snow before settling over the region for Wednesday and Thursday. A warm front will approach on Friday, with snow in the forecast.

Models Used: 18Z & 00Z NAM, HI-RES NAM & GFS

Short-Range:

Hi-Res NAM brings the heavy squalls to northern & central PA. The rest of the models handle the lake-effect fairly well. They also bring in the cold.

Temperatures at 850 mb could reach the -22-degree-C mark but not all that cold air will make it to the surface. We're looking at highs in the 15 to 25 degree range and lows in the 5 to 15 degreee range with wind chills reaching the zero mark in some areas at night.

FYI: Lake Erie is currently at +2°C.

Long-Range:

Temperatures will recover as the high moves off the Carolina coast. Models take the Friday system south of us, which is the best solution for a cold-air scenario (a "suppressed" storm track). However, some members of the 18Z GEFS take the low & cold front through PA, so this system is in the "watch closely" category.

-Jaron Breen

No comments:

Post a Comment