WEEKEND WEATHER OUTLOOK

[su_note note_color=”#d9f2da”]Thurs 7PM: Still uncertainty with Sunday’s forecast, with the NAM predicting rain for much of the day, while the GFS and FV3-GFS have the rain now later in the day. [/su_note]

I often post an “outlook” forecast on Tuesdays or Wednesdays. I’m glad I waited – the forecast for the weekend has changed significantly over the past few days.

Following a cold front passage on Friday night, skies will clear on Saturday.  Saturday looks to be a nice day with sunny skies and high temps near 70.  (Details Friday evening)

Sunday had initially looked to be another nice day, BUT the latest models, (NAM, FV3-GFS, EKDMOS) have the front that moved through Saturday stalling to our south with low pressure moving along the front.  An easterly flow will bring cooler temps (high in the low 60s) and rain is looking likely, especially for Sunday morning.

The GFS is an outlier this time around, with it holding off the rain until later in the day on Sunday.  Last week, the FV3-GFS had the correct forecast and I suspect its rainier forecast is correct for Sunday.

[su_note note_color=”#d9f2da”]Speaking of the FV3-GFS, the NWS will be upgrading the current GFS model (known as GFS v14) to the FV3-GFS (to be known as GFS v15.1)  on June 12th.  This is a major upgrade to the principal US weather model.

The FV3-GFS has been in development for many years and in comparison testing for over 3 years.  Its forecasts have been shown to be equal or better than the current GFS.[/su_note]

I’ll update the weekend forecast on Friday evening as usual.

SUNDAY UPDATE

[su_box title=”Weather Update 11 AM” box_color=”#defcdc” title_color=”#000000″]The latest NAM has a second slug of heavy rain moving in this evening, as an upper air disturbance (vorticity) slows exit of the surface low and enhances the precipitation.

There may be that taper in rain in the afternoon, but the NAM is forecasting heavy rain to return by 7-8 PM tonight.[/su_box]

From earlier this morning:

The latest short range models, the HRRR, RAP and NBH suggest that the main slug of rain tapers off today about 1- 2 PM with a break in the action until a second slug of precipitation arrives about 5 PM.  The HRRR even keeps that second slug of rain to our south.

The main GFS and NAM (2AM EDT runs)  keep the rain going into the evening.