THIS WEEK’S WEATHER

Update Fri 08/26 @ 11:43 AM

FYI, NOAA model data, usually available on their website called “NOMADS“, has been inconsistently available today.

NOAA, over recent days, has changed SSL certificates and has attempted to move their data over to Akamai’s CDN (Content Delivery Network).

This changeover has been fraught with difficulties over recent days. With NOMADS not working, NOAA’s backup server is overwhelmed.

It’s been difficult to get a complete download of the NAM, GFS and other models. With little data available, it’s been tough to do a forecast.

Updated Fri 8/26 8:23 AM — Many of last night’s models have significantly downplayed the chances of showers today in our area. The NAM-NEST continues with very widely scattered showers around 5 PM.

Update Thu 08/25 @ 8:11 PM — The weather has been on easy auto-pilot the past few days with increasingly warm and humid conditions.

Friday will have the warmest temperatures of this week with temps in the low 90s in many areas.

A weak front will move through Friday afternoon. Most of the US models have kept any showers to the far north of Philadelphia. But, this afternoon’s NBM, Canadian RGEM, and the ECMWF shows some light showers and thundershowers developing west of Philadelphia in the mid afternoon and moving eastward.

Canadian High Resolution (HRDPS) forecast for 4 PM Friday (1 hour Precipitation rate and 3 Hour accumulated Rain) (Click on image for a larger view.)

This is a relatively new development, since the previous days model runs had no showers in our area.

A bit of uncertainty for the weekend forecast, as the high pressure system behind the front will move off to our north creating an easterly flow here. Some degree of cloudiness and possibly some afternoon showers are possible as the models have an easterly flow converging with a westerly flow.

NBM surface winds Saturday 3 PM. The wind streams clearly show an area of horizontal wind convergence, forcing air upward causing showers to develop. (Click on image for a larger view.)

The Jersey shore may be most affected by this easterly flow. The uncertainty in the weekend forecast should clarify over the next day. Stay tuned.


Quiet and increasingly hot

Update Tue 08/23 @ 5:40 PM — The balance of the week will be influenced by a very weak upper flow. (The main jet flow is north into Canada.)—

NAEFS statistical “mode” Friday forecast jet stream level contours at 250 mb. Slow, stagnant flow over the US. The little wave in southwestern PA is a weak front. (Click on image for a larger view.)

Increasingly warm and humid through Friday. High temperatures upper 80s Wednesday and low 90s Thursday and Friday. A weak front moves through Friday evening. The long range models show little chance of rain in the coming week.


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WEEKEND WEATHER FORECAST

Update Sun 08/21 @ 8:41 PM — We had some break out showers Sunday afternoon that went through Citizen’s Bank Park. These had very limited coverage as they moved northward.

So…Are we really going to get about an inch of rain by Monday evening?

The latest RAP and GFS were in the 0.8- 1.0 inch range.

The NAM-NEST had the heavy rain splitting into two areas: far north of Philadelphia and far south of Philadelphia. The immediate PHL area was just getting about 0.4 inches—

18z NAM-NEST shows the heaviest rain far north and far south. It’s an outlier, but not to be ignored. It’s sorta what I expect during a drought where this sort precipitation miss has occurred several times before in recent months. (Click on image for a larger view.)

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