Rain for the Phillies on Sunday? Probably not.

Update Fri 10/21 @ 9:56 AM — As is often the case with coastal low pressure systems, the forecast speed and track varies from model to model. The general trend has been for a slower progression (except for the GFS) keeping any rain at bay until very late afternoon.

The latest GFS is an outlier with the system moving faster but further east. (still missing us!) A known bias of the current version 16 of the GFS is too fast movement of coastal systems.

Current GFS forecast for 2 PM Sunday—

The latest NAM at 5 PM Sunday—

The latest ECMWF has the rain moving in late in the afternoon and very light in the city—

Interestingly, the GEFS based on the GFS still has rain moving in during the afternoon, although quite light—

So..what’s going to happen? I’m going with the ECMWF-GEFS blended forecast right now. This is very similar to the NBM (model Blend). Very light rain moves in during the mid to late afternoon Sunday. It will be cloudy and somewhat windy. Not an ideal baseball weather backdrop, but it won’t affect the Phillies!

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Updated Thu 10/20 10:50 PM — Tonight’s NAM is slower with the rain moving in on Sunday. The rain moves in late afternoon to early evening. The NBM has some very light rain earlier.

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Update Thu 10/20 @ 5:38 PM — Many of this afternoon’s models have trended towards a slower northward movement of the coastal system on Sunday and things are looking somewhat more optimistic for a relatively dry (or much less wet) Sunday afternoon.

The latest NAM shows most of the rain still to our south at 1 PM—

The model blend (NBM) which incorporates many models but tends to lag 6-12 hours with changes, still shows some light rain here in the afternoon—

The afternoon GFS will be available shortly I’ll do a quick update later after 10:45 PM when this evening’s NAM becomes available.

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Update Thu 10/20 @ 9:49 AM —Increasingly nice weather through Saturday as high pressure builds in over us. Warming temperatures and sunny skies.

Unfortunately, the Phillies may have to play in the rain on Sunday, as all models have joined in the forecast of rain developing Sunday from a coastal low. The ECMWF has joined the NAEFS from yesterday with an upper low and sharp trough along the coast—

ECMWF accumuated rain forecast —

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Update Wed 10/19 @ 9:32 PM — The latest GFS continues with rain for Sunday, as does several other models. (The hold-out is the German ICON model which has a slower system that stays to our east.)

The latest GFS—

Possible change in Sunday’s weather forecast

The weekend forecast had been looking dandy. But the latest NAEFS shows a coastal low affecting our are with rain on Sunday. I’ll look closer at this later today.

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Updated Wed 10/19 8:16 AM —The Washington Post has a good article today on long range winter forecasts.

Update Tue 10/18 @ 5:07 PM — Continued chilly weather at night. Here’s the latest NBM minimum temperatures for Tuesday night into daybreak Wednesday—

Milder temperatures for the weekend. The weekend looks real good!

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Previously Posted Mon 5:53 PM —

It’s been well-advertised that a strong cold front is moving through today and considerably colder weather will be with us for the next few days.

A strong upper air low is over Canada and is gradually moving eastward, allowing colder air to move in tonight through Thursday.

Here’s the ECMWF model showing the current situation in the jet flow—

We’ll fall into the 30’s Tuesday night into Wednesday mornng. There’s a wide range of uncertainty (high standard deviation) regarding exact low temperatures—

It will be windy, especially Wednesday and Thursday—

Following the showers and thunderstorms moving through this evening (Monday), no storms on the horizon through the weekend.

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Update Fri 10/14 @ 9:39 AM — The clouds this morning were predicted by last night’s models (I hadn’t done a forecast for today.)

The clouds should dissipate by noontime.

A “closed” upper low is over Lake Superior. We’ll be getting the mild upper flow around the low for much of the weekend.

Jet stream by Sunday—

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Update Thu 10/13 @ 7:59 PM — The system has slowed down somewhat due to the low pressure development and storms are ‘training’ south to north in the area of the red box below. The NWS issuing a flash flood warning for that area. Rainfall amounts of 1-3+ inches have fallen so far in that area.

Update Thu 10/13 @ 5:26 PM — As forecast, low pressure has developed ahead of the front and will move up over us early this evening. The latest HRRR shows strong dynamics (high vertical shear and high helicity) moving through the western suburbs about 9 PM—

Update Thu 10/13 @ 7:33 AM — Showers move in early morning, then periods of rain increasing in intensity towards evening and early evening. Precipitation totals are now in the 0.4- 0.8 inch range with a few locally higher amounts.

Main front moves through between 7:30 -10 PM with very windy conditions and a fast burst of heavier rain. Severe thunderstorms not likely. (Winds gusting to 30-35 mph with front.)

Update Wed 10/12 @ 5:51 PM — The models have backed off considerably from forecasting wild weather for Thursday. Precipitation totals are now in the 0.5- 0.8 inch range. Winds will be gusting about 30 mph at times. Some thunderstorms are possible but they’re not going to be severe. Best chance for thunder is after 7 PM. Some rain is possible as early as Thursday morning, Heaviest rain late afternoon and especially the evening hours.

Complicating the forecast is the expected development of low pressure along the front which may move much of the heaviest rain off the coast. It’s certainly “confusing” the forecast and making some forecast specifics low confidence—

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Strong Cold Front Passage Thursday

Update Wed 10/12 @ 8:13 AM — It appears that some rain may move in earlier on Thursday than forecast yesterday. Some showers in the morning now expected. Strong winds and rainfall amounts 1-1.75 inches are likely with this system. I’m not so sure about severe thunderstorms. Updates later.

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Update Tue 10/11 @ 10:13 AM — A weak system will bring cloudiness in Wednesday afternoon ahead of a strong cold front that will move in and affect our weather Thursday afternoon through evening. The latest NBM is forecasting about 2 inches of rain by late Thursday night.

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Tranquil until Thursday. Then it gets interesting

A rather strong cold front is forecast to move through Thursday evening.

All the ingredients for some ‘interest weather’ appear to be in play for Thursday afternoon and early evening— elevated CAPE, elevated helicity, elevated vertical shear and a strong jet streak presence. (All the ingredients that we never really saw for much or all of our dry summer.) Stay tuned.

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Previously Posted Sun 8:01 PM —

A fairly tranquil weather period early this week as high pressure gradually moderates in temperature. Fair weather through early Wednesday. Wednesday looks to be the mildest day, but some cloudiness moves in during the afternoon.

Of interest is a rather strong cold front that will move through Thursday with rain and maybe even some thunderstorms—