Saturday, April 06, 2013

Still Splitting Hairs About Next Week's Warmth Duration

Going into last night, modeling still had differences of opinion about the duration of the warmup for next week, how quickly we warm up, and whether we get a backdoor front slipping on down.  Details matter...and in this case the strength of an organizing storm system in the Midwest and Great Lakes early next week will determine how far north a warm front holds, whether or not a backdoor front slips south, and how warm we get.  You can see those differences illustrated below for Wednesday at 8 AM between the GFS and Euro computer models -- the GFS is a stronger storm in the Midwest while the Euro is weaker.  The resulting difference is the push of warmth up the East Coast is much stronger on the GFS compared to the Euro.

Also, a low over Newfoundland is stronger and a bit southwest on the Euro than on the GFS -- this results in a sharp push of a backdoor front down the East Coast on the Euro.

While Sunday through Tuesday should be mild -- with Sunday and Tuesday perhaps warmer than Monday if you believe the Euro, with each day progressively warmer on the GFS, the question turns into Wednesday and Thursday on the models.  With the backdoor front on the Euro, the temperature difference on the models is over 20 degrees (mid 70's on GFS, mid 50's on Euro) for Wednesday afternoon.

The GFS, with its aggressive push of warmth, sets the stage for a shot at thunderstorms as the cold front pushes on through Thursday afternoon and evening, with perhaps a strong or severe thunderstorm event for portions of Pennsylvania and Maryland.  The Euro runs the backdoor front through Maryland, Delaware, and Virginia, resulting in us being stuck in a colder round of rain...with perhaps some thunder...but with temperatures that are much colder than the GFS' depiction.

We likely will see some sort of movement towards one or the other -- perhaps compromise in between with a lean towards one or the other -- over the next day or two.  Fans of warmth will be cheering on the 70' of persistent chill will hope for the backdoor front.  It's April and the battle will be waged.