Daily Archives: Sunday, April 26, 2020 9:53 pm

Philadelphia Area Weather Forecasts

MONDAY FORECAST

[su_note note_color=”#ffffff”]Updated Mon 04:58 PM — Sometimes the weather model forecasts are just terrible. Often, they’re incredibly impressive. Here’s today’s KPHL radar at 4:52 PM; compare to the weather model simulated radar graphic in the update just below.

Terminal Doppler Weather Radar KPHL at 4:52 PM today       Courtesy WeatherTap.com

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[su_note note_color=”#ffffff”]Updated Mon 11:58 AM — Despite the appearance of cloud thinning right now, all of this morning’s short range models have scattered sprinkles/showers breaking out late afternoon (~4PM).

HIRESW Simulated Radar 4 PM.  (Exact placement of radar rain is never literally exact.)  Click on image for larger view.

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[su_note note_color=”#ffffff”]Updated Mon 07:48 AM —Last night’s models suggest some partial clearing possible very late afternoon or early evening Monday.

After more rain Wednesday into Thursday, a change to a much warmer, more Spring-like weather pattern is likely to start this weekend, although plenty of showers are still showing for next week.[/su_note]

Surface low pressure slowly moves away on Monday, but an upper air trough swings through during the afternoon.

Monday will be cloudy with spotty light showers or drizzle.  It will remain very cool.  Highest chance of showers is in the morning and again mid to late afternoon.  High 51.2º sd 2.1º

Clearing will wait until Tuesday morning but more clouds may move in Tuesday afternoon ahead of the next system.

Weather Updates

WEEKEND FORECAST UPDATE

[su_note note_color=”#ffffff”]Updated Sun 11:49 AM — This morning’s GFS data, just available, continues to show the convective precipitation to our south at 7 PM. (See the main forecast  update below.)

GFS Convective Precipitation forecast 7PM Sunday

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[su_note note_color=”#ffffff”]Updated Sun 10:34 AM — The newer high resolution models becoming available this morning continues with my forecast update just below.  The somewhat older NAM model just available still shows some convective activity possible in the afternoon—

Latest NAM model with convective activity shown in the brighter green/orange/yellow at 2 PM

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Last night’s models have backed away from the heavy rains expected in the Philadelphia area this morning.  However, light intermittent rain will continue through today.   Total QPF predictions of 1 + inches of rain have been reduced down into the 0.3-0.6 range.

High temp 53.0º sd 4.1º. (High spread uncertainty)

Additionally, there had been expected to be some convective activity (thunderstorms) in the late afternoon.  That activity is now predicted to be diminished and, if it occurs, will break out south of Philadelphia, closer to far south Jersey and Wilmington during the early evening.

The vertically stacked low pressure system causing this will be slow to depart and will likely affect our weather into Monday.