FORECAST UPDATE

As mentioned in a previous forecast, with an upper closed low, the models rarely accurately predict the placement of the heavy rains and such was the case yesterday.  In fact, all of the models over-predicted rainfall, including the EMCWF (European).    Most areas in PHL and immediate surrounding areas only had 0.75 to 1 inch of rain.  The heaviest rain was in Maryland and near Baltimore.

(When it snows, everyone knows when the forecast QPF isn’t correct; when it rains, fewer people realize it.)

For today, Sunday, the NAM has some hazy sunshine breaking out by  morning or early afternoon. But it also shows high instability in the early afternoon with showers as early as 2 PM. The chance of showers continues thorough the evening.   These will be random and scattered.

The GFS LAMPS has increased chance of showers and thundershowers in the late afternoon.  The experimental NBM (National Blend of Models) has a high chance of showers and some embedded thundershowers during  late afternoon (4 PM) and evening, as does the EMCWF.

So, not a washout, but unsettled, with showers especially likely after 4 PM into the evening.

FORECAST UPDATE

This morning’s models haven’t changes significantly. Widely scattered showers are now in Delaware.   The short range models have the rain moving into the immediate  Philadelphia between noon and 2 PM, earlier to the south.   The rain continues into the late evening, heavy at times.

The axis of the heaviest precip shows some variation among the models, with areas just to our south and areas of NJ having the heaviest.   It’s very difficult to pin point the exact placement of the heaviest precipitation.

Sunday is currently looking relatively dry, with only very widely scattered showers; most of the area rain free.

Weather… and Other Things 'Up in the Air'