Philadelphia Weather Outlook

WEEKEND WEATHER OUTLOOK- UPDATE

[su_box title=”Forecast Update Thursday AM” box_color=”#defcdc” title_color=”#000000″]The latest models show a change in the forecast. The coastal low gives us rain for Saturday, but departs much more quickly now. Sunday will be windy and chillly but not rainy. The second low moves in on Monday.[/su_box]

The latest models show a coastal low bringing us rain on Saturday as an upper low to the west along with another low in the Midwest causes the coastal low to linger over our area into early Sunday.  The phasing that was considered a possibility to create a superstorm is no longer being depicted.

So, not the best weekend, weather-wise, as rain is likely for Saturday and early Sunday morning. Much of Sunday will be unsettled, cloudy and windy.

I’ll update on Friday.

Philadelphia Weather Outlook

Coastal Storm Saturday?

Much uncertainty about the intensity and timing of a coastal storm expected to develop and move up the coast, affecting our area sometime early Saturday into Sunday.  Several models have backed away from a super storm that had been forecast by the European Model (ECMWF) and Canadian (CMC) models and to some extent the GFS.

The latest model forecasts suggest that the northern stream and southern stream low pressure systems won’t phase because the northern stream disturbance will arrive too late.  However, the ECMWF still has a considerable storm forming and affecting us Saturday into Sunday.

The latest GFS moves the low pressure through faster and keeps the two storms separate. In fact the lack of phasing with the GFS keeps the southern stream coastal storm moving fast and robbing it of some punch.

It’s still way too early to know which way things will go, but the trend is towards a rainy but otherwise unremarkable Saturday.

I’ve been following this for several days and I’ll update if things change.

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST- EARLY EDITION

A weak front will move through Philadelphia in the early morning hours Saturday, accompanied by some showers, mostly before daybreak.

I’m going to try something for this forecast version- it will be based on the newer statistical models– the new National Blend of Models (NBM) and the new Ensemble Kernel Density Model Output Statistics.  (EKDMOS).  We’ll see how this goes.   🙂

Saturday will start cloudy, but skies will begin to clear during the mid morning hours and partly sunny skies is expected for much of the day.   High will be between 61 (NBM) or 66 (EKDMOS) .  It will be windy!

Clouds move in later Saturday afternoon as a strong  secondary cold front moves through.  More showers possible during Saturday night.

Sunday will be mostly sunny with some clouds, chilly and  windy with a high of 49(NBM) to 52 (EKDMOS).

(I’ve been incorporating the experimental NBM and EKDMOS for these forecasts over the past year.  The EKDMOS is pretty good with forecasting high temperatures.  The NBM 3.1 , which now includes the European Models in the blend, was promoted from experimental to operational on Oct 3rd.   Let’s see how it does this weekend.)

Look for an update tonight.

[su_box title=”Forecast Update Friday 6 PM” box_color=”#defcdc” title_color=”#000000″]The forecast remains on track. Saturday, after pre-dawn showers, becomes mostly sunny with some periods of clouds. Windy. High 63. Some sprinkles Saturday night as a secondary cold front moves through. Sunday is mostly sunny, windy and chilly. High 50. [/su_box]

[su_note note_color=”#d9f2da”]This weekend’s forecast postmortem: The NBM did pretty good with the high temperatures, winds and precipitation (including Sunday’s brief shower that occurred about 8 AM instead of the predicted 7 AM.) BUT, it did very poorly with the cloudiness/sky cover prediction on both days. It was much cloudier than the NBM forecast.  I’ve noticed this in past months.  So I’ll have to go back to the GFS humidity fields for cloud cover in future forecasts.    [/su_note]

 

Weather… and Other Things 'Up in the Air'