Monthly Archives: April 2019

Philadelphia Area Weather Forecasts

WEEKEND WEATHER FORECAST- FRI EARLY EDITION

[su_box title=”Weather Forecast Update Fri PM” box_color=”#defcdc” title_color=”#000000″]Most of the forecast below remains intact. The period of cloudiness mid and late Saturday morning will be just a few hours duration.   (The clouds stay to our north on the latest models.) Very windy. High temperatures as shown 60-62.

Sunday is looking a bit wetter with the latest GFS. Light showers early part of the day, QPF about 0.15- 0.20 inches water. Clearing later in the afternoon. Continued cool.  [/su_box]

Low pressure moving up to our northwest on Friday will an associated warm front will be scattered showers and low clouds today (Friday). A strong  cold front will move through between 5 and 8 PM Friday evening, with showers and some heavy thunderstorms possible.

Rain ends later Friday evening (tapering as early as 9 PM) and cooler air moves in for Saturday.

Saturday will start with a fair amount of cloudiness in the morning, especially between 9 AM and  1PM as a strong upper air disturbance moves though.  Clouds thin and lift in the early to mid afternoon with increasing sunshine.  It will be windy (WNW) with gusts over 30 mph!  Highs 60-62.

Another low pressure disturbance moves through on Sunday. Sunday will be cloudy, but precipitation is [currently] expected to be fairly light and scattered. Areas east of PHL will have light precip continue in the afternoon.  High near 60.

[su_highlight](There is still significant uncertainty with Sunday’s forecast as the statistical models have quite a bit of spread in the forecast.)[/su_highlight]

 

Philadelphia Weather Outlook

WEEKEND WEATHER OUTLOOK

[su_box title=”Weather Outlook Updates ” box_color=”#defcdc” title_color=”#000000″]The latest NAM brings the weekend in-range. Saturday looks to be sunny but very windy!

Saturday looks to be dry… cloudy in the morning with clearing and sun in the afternoon. Very windy!

Sunday is looking drier and partly sunny. Uncertain forecast for Sunday – NAM and GFS are quite different.

(This morning’s GFS is more pessimistic about Sunday with showers.)

Today’s models haven’t done well. Neither the NAM nor the GFS had predicted the light showers this afternoon! The weekend forecast is probably low a low confidence forecast. My rule of thumb- if the models are wrong in the short term, they are not reliable in the longer term.

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A series of low pressure systems will affect our area over the next week, following a path of a zonal (flat) jet flow.

The low pressure system bringing rain on Friday is expected to depart and intensify on Saturday over New England.   For Saturday, we will have a mix of sun and clouds and high temps near 68.  It will be windy.

Another low pressure system will affect our area on Sunday.  There are large differences in the track of this low, with the GFS-FV3  having the low move to our north while the GFS has it right over us.  The track will determine the amount of showers/rain we will get.  Right now it appears the precipitation will be light. There’s a large range of temperatures forecast as well.   But too much uncertainty right now in the Sunday forecast.   Stay tuned.

Weather Updates

WEATHER UPDATE- SAT AM

[su_box title=”Weather Update Sat 10:30 AM” box_color=”#defcdc” title_color=”#000000″]Based on the latest NAM, showers have ended but widely scattered light sprinkles are possible. Low clouds lifting to brighter skies may be delayed until 2-3 PM today.[/su_box]

from earlier today:

The gusty windy conditions (Gusts to 35 mph) will continue and diminish later in the afternoon.

The rain ends by 11 AM.

Based on the 2 AM (06Z) NAM and GFS model runs, the low clouds should lift between noon and 1 PM, leaving brighter skies and some sun through a layer of higher cirrus clouds.   Continued improvement in sky cover later in the afternoon. High temp 74-76.

Currently, Sunday looks dry except some showers may develop in far western suburbs in the mid afternoon. High 67-69.