Monsoon's Wet Weather Update for Wednesday, 10 December 2008
Wednesday will begin in the upper 50s to near 60 with all rain—and quite a bit (up to an inch in some places) after a drizzly early morning. Rain tapers in the evening, but clouds stick around as another round of rain will ride along the frontal boundary on Thursday. Windy. Temperatures dropping throughout the day to the upper 30s overnight.
Thursday late morning into Thursday night, another round comes in (may linger to Friday morning) which looks to bring heavier rain. I think it’s all rain with some sleet/freezing rain on the tail end for our area.
Let me talk about that “tail end”: this is the tricky part. If the colder air dips in underneath the warmer air aloft (the air that’s helping to moderate temperatures on Wednesday), and it happens a bit earlier than expected, we could a sleet/rain mix by rush hour Thursday and a few inches of accumulating snow throughout the evening and overnight before it tapers off. But I think the milder air will win out where and when it counts, so that the precipitation for our area will be nearly all rain with some sleet and freezing rain mixing in at the tail end.
For Philadelphia and the surrounding counties, there will be little or no “tail end”; that is to say, it’s an all rain event, so no worries about deteriorating driving conditions on Thursday night.
Another inch or two of rain in this second “wave” makes 3+ in some places for both waves of rainfall. Breezy and colder Thursday with highs only getting into the upper 30s and dropping at night through the 30s to below freezing. A few flurries or snow showers overnight and into early Friday morning may deliver a coating to an inch.
Friday is very cold with a high only in the mid 30s and low in the low 20s—perhaps the teens.
Delays/cancellations: Wednesday, no chance. Thursday, no delay or cancellation, but 10% early dismissal. Friday, 65% delay; 30% chance of cancellation.
Looking ahead: next week’s Wednesday-Thursday storm is setting up nicely, but high temperatures will be into the 40s for the week, so it’s looking like rain right now. But it’s still early.
I’ll send out an update tomorrow (Thursday) if anything changes...