Category Archives: Weather Updates


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Update Sat 05:08 PM —Forecast Review: The rain ended as predicted but the clearing forecast by the models didn’t occur.  We had 1.92 inches rain.  The high temp was about 46º, much less than the 53º predicted or my forecast of 57º.

The latest NAM NEST shows rain ending about 2-4 PM this afternoon. Cloud cover depiction (white) shows some clearing about 4 -5 PM.

NAM NEST simulated Radar, wind barbs and cloud cover depiction

The latest hourly HRRR (High Resolution Rapid Refresh) still shows rain until 3-4 PM today.

HRRR Saturday forecast hourly rain accumulation- Click for larger image.


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Update Sun 04:34 PM — OK, it WAS a beautiful spring-like day, even though didn’t reach 70º.

Some interesting weather on tap for next Saturday, likely changing to all rain.

Today,  I’m simply playing with a ‘live blogging’  type format.   This may be a cleaner look for rapidly changing weather situations 

instead of the box format I’d been using previously.

Update Sun 12:37 PM – The temps are maintaining about 64-65 and the winds have diminished somewhat.   Temps expected to remain in low 60s until 3-4 PM.

Update Sun  08:30 AM —  The front moved through as forecast and the winds have picked up.  Expect sunny skies for the rest of the day  with winds gradually diminishing.

…Posted this morning—

As expected, we are NOT going to reach 70º today; all of the models had started to back off of that forecast on Friday evening and have continued with a forecast high of about 64º today, probably already reached.

Here’s the EKDMOS I posted on Friday–

Friday’s EKDMOS temp forecast for the upcoming days:

The EKDMOS, being an advanced statistical post-processing handling of 20 version variations (called “perturbations”) of the GFS model, shows the actual potential forecast temperature range being forecast was 63-70.   The average was closer to 65 (red line).  I was persuaded initially to go with the upper limit, but I began having my doubts as the the models rolled in Friday evening and posted my skepticism in a later update.

Temperatures will gradually fall into and through the 50s today. With the wind, the “spring like temperatures” predicted by the weather entertainers won’t make all that much sense.

Still no chance of any snow predicted in coming weeks, although a mixed-precipitation event is possible on Saturday before a change to rain.


The warm front clearly did NOT make it north of the Philadelphia area, as had been previously predicted by the GFS.  It’s in the 40s.  The short range models got this one correct yesterday.  Not a surprise; the new GFS has been biased to the warm side.

Today’s GFS has caught up with short range models.  Here’s the latest GFS below.  We don’t get out of the 40s north of the city.

GFS forecast temperatures for 3 PM Monday. Click for larger image


Speaking of temperatures, here’s the latest NBM (National Blend of Models) forecast for New Years Eve- Midnight.  Clear skies.   Winds 7-9 mph.

NBM 12:01 Jan 1, 2020    Click for larger image


Update Sun 12 PM: So, the current radar shows precipitation moving in sooner than any models had predicted.  Rain may start as early as 1 PM.

Most of last night’s models continue with the idea that rain begins in the general Philadelphia area around 3-4 PM today, Sunday. A remaining exception is the high resolution Canadian (HRDPS) which waits until 7 PM for the rain to start.

Rain may be heavy overnight and into Monday morning, then more light and scattered.

A warm front will try to make its way into Philadelphia and areas on a line to its south on Monday morning.  If it does, temps will rise into the low 60s.

However, only the GFS has it making its way as far north as Willow Grove.  The NAM, NAMNEST and the Canadian HRDPS, GDPS  keep it further south.  Areas that remain north of the warm front will remain in the low 50s. (Warm fronts are not as distinct as cold fronts.) So it may not get as warm as previously though on Monday.

NAM warm front position 12 PM Monday.  (NAM Temp, wind streamlines)

Most models have a cold front moving through about 2-3 PM, dropping temperatures.