January 15, 2001
A dreary January day on tap for the Delaware Valley on Monday, then many questions arise with the forecast beyond Tuesday. Intermittent rain will be the story for the remainder of the overnight hours into Monday morning. Temperatures will gradually rise to around 40 by morning. Monday will start off with rain but will taper off to showers early. A few showers are possible throughout the day and it will remain cloudy. Highs Monday in the mid 40s. Things will begin to dry up later Monday, but Monday night will remain mostly cloudy. Lows around freezing. Tuesday will be partly cloudy with the high in the low 40s.
The forecast beyond Tuesday is a forecaster's nightmare (well, enough to give a headache anyway). Computer guidance has taken two separate paths as to the evolution of the weather for mid to late week. The majority of guidance, at this point, sends a series of upper level disturbances harmlessly through the Northeast doing nothing more than ushering in cold high pressure. On the other hand, the usually reliably Aviation model, phases northern and southern energy on two separate occasions this week, once Wednesday and again on Saturday, leading to two possible wintry events for the Northeast. However, the AVN is virtually alone with this depiction (save for the EC, another very reliable model for medium range pedictions).
During the day Wednesday, a piece of energy will be ejected out of the southwest and start to head ENE. Associated with that disturbace is an area of low pressure that will track across the Southern Texas border. Meanwhile, another piece of energy will be positioned North of Wisconsin. Question is, will the northern energy zip eastward along the Canadian border as depicted by the ETA/GGEM/UKMET/NGM or will the energy dig just enough to phase the two vorticities per the AVN/EC and cause a storm to move farther north as opposed to off the SE Coast? Will go with increasing clouds on Wednesday, highs in the upper 30s, chance of a wintry mix late in the day for now.
Thursday will be partly cloudy with a high in the mid 30s. Friday will also be partly cloudy with highs in the mid 30s. Then things get tricky for the weekend once again.
The setup for late in the week looks very similair to the event on Wednesday. This time around, a larger, more organized shortwave will be ejecting out of the southwest while a shortwave begins to dig into the Great Lakes region. Timing is everything as is depicted between the AVN/GGEM/EC. All models show some type of phasing, however there are noticeable differences at the upper levels. The AVN keeps the ejecting s/w out of the Southwest closed a bit longer, hence developing a more potent system in the Southeast by late Friday as the two s/w begin to phase just past 126 hours. For whatever it's worth, the AVN would imply a classic winter storm track with redevelopment just off the mid-Atlantic. The EC opens the s/w quicker, thus developing a weaker, more sheared out system by late Friday. The GGEM is more sheared with southern s/w at 120 hours and a lot slower to phase. Thus, the GGEM sends a sheared out system off the SE coast and hardly develops it at all. Just a reminder, the mid week system/non system will have huge implications for next weekend's weather, so confidence is low with the forecast beyond Wednesday.
So, a potentially active week lies ahead for our area. Confidence is average from now through Wednesday, and increasingly less confident past Thursday as mid-week holds several implications with the forecast for late week. Went too far in depth for the late week event. Need to see what happens in the next 36-60 hours first before confidence is raised. Things will dry out late Monday with a decent, but chilly, day on tap for Tuesday. Clouds will increase Wednesday with the chance for snow or rain late. Thursday and Friday look quiet with highs in the mid 30s. A chance of snow on Saturday. Another update will be available late Monday/very early Tuesday. Have a happy holiday.
