Synopsis: A low pressure will form along the gulf coast and move northeast off the North Carolina coast this weekend. Cold air will be in place as the low pressure nears the region which will likely bring wintery precip to the triangle. Forecast confidence is very low.
Discussion: A Miller A low will move up the North Carolina coast increasing moisture flux from the Atlantic into the triangle by Friday afternoon. This low will exit the area slowly first bringing in a round of precip due to overrunning warm advection over a fairly strong cold pool at the surface. A 2nd round of precip affiliated with the deformation band will occur later in the weekend. The GFS and ECMWF are in decently good agreement on the general location and timing of the low pressure. I am looking at GFS Bufkit soundings to determine first guess precip type. Forecast confidence is very low due to precip type remaining near the mixed bag region of the nomogram. Diabatic processes could play a large part in the precip type especially Friday afternoon as the precip begins. Also, this is a cold air damming scenario with cold air filtering in between a fairly weak high to the Northwest and a Low to the northeast. NWS RAH mentioned that this storm compares generally well with a storm in 05 in which very little wintery precip fell in the region. With that in mind this is a completely different storm. GFS and every other model for that matter tends to warm temps too much during a CAD event. This fact makes me want to go with an icier/snowier scenario for the triangle as the GFS already predicting a decent amount of ice and snow, especially in the deformation. Climatology however does not support this type of system as a major winter event however, which is why my confidence is so low. On top of that there will be a tight gradient between the rain/mix/snow lines. Also, diabatic processes will turn borderline temps for freezing rain into temps for rain. Right now it's too far out to truly pinpoint the exact location of the low and the strength of the cold air.
But I will forecast what I see as of now... This is likely to change!
Friday afternoon: A 60% chance of snow possibly mixed with rain
Friday night: 70% chance of snow mixing with freezing rain/rain and sleet by 8PM and then changing to all rain/freezing rain/sleet mix.
Saturday: Rain quickly changing over to freezing rain/drizzle before ending.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment