THIS WEEK’S WEATHER

Updated Wed 8/31 9:19 PM — A year ago tomorrow (Thursday) we were dealing with storm IDA, tornadoes, and 5-6 inch rains. What a difference a year makes!

Update Tue 08/30 @ 10:11 PM — How much rain did we get?

MRMS precipitation estimates (Click on image for a larger view.)
Tue 08/30 @ 8:47 PM —Forecast Review— The storms hung together better than I had forecast. A fast moving thin line of storms that didn’t have time to put down much accumulation.

Radar loop just before the storms got into Philadelphia. They regenerated more than I had forecast. (Click on image for a larger view.)

I’m waiting for an MRMS summary to become available to see if any areas got substantial rain. I know that my neck of the woods got very little.

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WEEKEND WEATHER FORECAST

Forecast Review— 08/28 @ 5:01 PM — Some showers did develop about 2-4 PM today as forecast but most areas just saw clouds—
NEXRAD radar loop this afternoon. Some showers did actually develop, but most areas saw only increased cloudiness

Note that NOAA model data is still delayed or partially unavailable due server issues as described over recent days.

Update Sun 08/28 @ 11:31 AM — There were some showers in NJ yesterday and this morning’s models continue to forecast some pop-up showers moving in from the east by 4 PM today, Sunday —

Today’s 12z HREF forecast model shows considerable showers at 4 PM today. Many models have been over-forecasting rain over the past day and I’m not all that confident that we’ll see so many areas with showers today. (Click on image for a larger view.)

Updated Sun 8/28 1:30 AM —Several of tonight’s models show showers and thunderstorms developing over the immediate Philadelphia area Sunday afternoon into Sunday evening.


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Posted Fri 9:46 PM

Sunday

Partly sunny, again with periods of clouds and a few widely scattered showers from Philadelphia and east.  High 87.3° sd 3.2° (higher than average spread) NBM model, Blue Bell. 

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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