Weather Updates

WEEKEND WEATHER UPDATE SUNDAY

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[su_note note_color=”#d9f2da”]Latest models from this morning show only average instability and thermodynamics parameters. Severe thunderstorms are not likely in our neck of the woods, although heavy rain is always possible. [/su_note]

HIREF (High Resolution Ensemble Forecast) about 5 PM

Sunday will have sun, and periods of clouds at times.  This morning’s forecast will be based on the HIREF, an “ensemble model” based on the two versions of the WRF that statistically combines the WRF model versions and includes the NAM-NEST model.

High temperature today about 86 with the increased amount of sunshine.  More humid also, with dew points in the mid 60s.

Very widely scattered showers and thunderstorms about 2 PM.

The main thunderstorm activity moves in from the west about 4:30-6:00 PM and lingers into the evening hours. (See above graphic)

Weather Updates

WEEKEND WEATHER UPDATE

The latest data has come in.  Sunday will have periods of clouds and sun at times.  The WRF model has a high temperature of 86-88 with the increased sunshine forecast.  It will be more humid.

There’s an increased chance of scattered showers/thunderstorms about 2 PM, then a lull.

Another increase in  showers and thunderstorms about 6 PM as a weak front moves through.  These storms will be scattered.

The front is expected to stall just south of us.  One version of the WRF (there are two versions) shows another round of showers and thunderstorms again about midnight.

 

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST

[su_note note_color=”#d9f2da”]Fri 11:30 PM – The two versions of the WRF model just available show showers as early as 1PM Sunday and more sun than the GFS or NAM. High temp 86-88 on Sunday.

The WRF model forecasts have been really impressive lately. The downside is the model comes out late, only forecasts out to 48 hours and is only run twice daily. But accuracy is worth the wait.  [/su_note]

[su_note note_color=”#d9f2da”]Fri 10:45 PM – Tonight’s NAM has more sun, less cloudiness on Saturday afternoon, more clouds on Sunday. [/su_note]

Saturday will begin with the incredibly nice weather we had today (Friday).

As the crisp, unseasonable airmass over us moves off to the east, weak low pressure from the Midwest will pass to our north on Sunday. A southwesterly flow of increasingly humid and unstable air will move in for Sunday.

Saturday will start sunny and delightful.  High temperature 82-84. During the afternoon a very weak “pseudo warm front” will approach.  An increase in cloudiness expected with mostly cloudy skies by late afternoon.

Sunday will be mostly cloudy (some bright spots possible), warm and increasingly humid. As the warm front slowly moves to our north Sunday, light showers  are possible in the morning, mostly far north and west, although a sprinkle or quick shower can’t be ruled out here.  With increasing heat and humidity and an upper air disturbance moving through, expect showers and thunderstorms to break out in the afternoon.

The FV3-GFS I spoke of earlier this week has fully replaced the older GFS. The “FV3-GFS” after this past Wednesday IS the “GFS” now.

The GFS has the chance of light showers as early as 1 PM.  Most of the shower and thunderstorm activity is expected during the late afternoon and evening hours according to both the NAM and GFS.

I’ll update over the weekend to give a more specific timing and indicate whether some areas will have any severe weather.

[su_note note_color=”#d9f2da”]What’s with this cool weather? Remember, we’re just coming off the 10 year sunspot cycle minimum. Back in the summer of 2009, we had fewer days in the 90s and many similar very cool spells. I’ve talked about this in the past.[/su_note]

Weather… and Other Things 'Up in the Air'