Disc: We have a parade of systems moving thru in the next week or so, and none of them, even today's, which is a short term concern, is not very clear cut.
Currently: Low pressure is over NE IN. A cold front, with cold occlusion, extends from the low down thru Central PA. A warm front was draped from Central PA thru SNJ. High pressure was located off Nova Scotia. Most of CT is dry right now, but a few showers are clipping extreme SW CT.
Rest of today: Adding a rest of today period to cover the next few hours. Other than showers clipping the far SW, most of the daylight hrs should be relatively dry. As far as temps, guidance is in pretty good agreement. Expect highs in the mid to upper 50s.
Tonight: A couple of really big questions remain as to how much rain falls. The rain along the cold front is training along the front. The problem is, a lot of times when the rain bands make such slow progess eastward, they can essentially "rain themselves out" over one area. The GFS has a strange, but plausible, evolution, where it shows the rain falling apart as it heads towards CT, then picking up Atlc moisture and re-energizing over E CT. The NBM guidance does not really agree with this evolution, and has much more uniform totals, around an inch and a half for the entire state, with just a slow decay from W to E. This evolution kind of makes more sense. Either way, it will rain, heavy at times, mainly in the 2nd part of the night. I'll keep t-storms out of tonight's forecast, as that element of the storm will definitely lose steam before getting here. Winds should stay fairly gusty until dawn, so keep that in the fcst all night, with gusts to at least 30 MPH, possibly higher in heavier showers. As for temps, I'll go way above guidance and keep temps steady thru the night. There is no fropa during the night, and strong S winds, so no reason for temps to drop much. Expect temps to drop to around 50 with the onset of rain and then basically sit there.
Tomorrow: After some morning sun, showers and t-storms will redevelop. However, the main focus will be closer to the stalled low pressure system, i.e. west of the Hudson River. I still feel that some showers and storms will make it into CT, but I am having a hard time believing any get into Srn New London/Srn Middlesex Counties, so no showers will be included there. The further west, and away from water you go, the stronger and more widespread these storms will be. So I will include a chance of strong storms in the NW Hills (i.e. Nrn Fairfield and Litchfield). For the rest of the state, scattered showers and storms. As for temps, guidance is in excellent agreement, and I see no benefit in trying to make it any better. So highs should be 60 to 65 degrees.
Tomorrow Night/Sat: All this wx might be worth it if we get a nice weekend, and it appears a beautiful weekend is in store. For Saturday, expect plenty of sun, and pleasant temps. Guidance is in good agreement, so no major changes planned. Highs should be around 60 degrees, but the coolest areas will be along the S Coast, with a developing afternoon sea breeze.
Big questions revolve around Sunday's forecast. A developing mesoscale convective system (MCS) could have big impacts on the fcst for Sun. The GFS, first off, is much faster than everything, and also weaker. Weaker, in a sense, would be easier to predict, for two reasons. First, we wouldn't have convection ruining model fcsts. Secondly, it would be more spread out, so the entire area would get a general light rain. The ECMWF, on the other hand, is much stronger with this feature, and much slower. The GFS would occur Sun aftn, while the ECMWF would be more like early Mon morn. The ECMWF centers the action around NYC, which keeps anyone N of the Merritt Pkwy dry. A solution like the ECMWF would mean 1-3" of rain centered around a 40-mile wide area, with nothing N or S of there. Because of all this uncertainty, and the possibility for more sea breezes, I went several degrees below guidance on Sunday. There is just too much uncertainty to buy really warm temps yet. So Sun's temps for now are being kept the same as Sat: 60-65.
Not much going on for Mon or Tues. Both days should be pleasant, with reasonable temps,a bit below normal. For both days, guidance has been accepted pretty much as is, as there's usually no reason to deviate too much on those types of days, esp when said days are 4 and 5 days away. A sneaky little cold front moves thru Mon nite. It is moisture-starved, so don't expect any rain with it. But it will be about 5 deg cooler on Tues. So highs should be in the mid 60s Monday and near 60 Tuesday. Both days should be 3 to 5 degs colder in the NW Hills.
The next potential wx problem is Weds. A weak coastal low scoots to our S. Although the actual low pressure center appears fairly weak, there could be a good amt of overrunning moisture with it. In addition, models have been trending N with it. Obviously, as of now, the S coast is most favored. However, I wouldn't be surprised if this trends into an entire state rainfall. I went well below NBM temps, because of the trend N with the rain and the fact that this is not yet reflected in NBM guidance. This yields quite chilly temps for the time of year, with highs of only 50-55 expected!
Skies clear out Thurs. There is very strong cold air advection, relative to the time of year. For that reason, I undercut guidance temps by a couple degrees. Highs should only be in the mid to upper 50s, despite sun!
Looks like chilly wx continues right into the day 6-10 period. There could even be a few sleet/graupel showers over Mother's Day weekend, esp in the NW hills.
Now, let's take a graphic look at some systems slated to affect our area. I'll show tonight's rain and Sunday's potential. I'll post them as depicted by the GFS. Keep in mind, esp for the Sun night potential, that other guidance is still very different. Here is tonight's system. The wild card is all that moisture out in E PA and how exactly it affects our area.
Currently: Low pressure is over NE IN. A cold front, with cold occlusion, extends from the low down thru Central PA. A warm front was draped from Central PA thru SNJ. High pressure was located off Nova Scotia. Most of CT is dry right now, but a few showers are clipping extreme SW CT.
Rest of today: Adding a rest of today period to cover the next few hours. Other than showers clipping the far SW, most of the daylight hrs should be relatively dry. As far as temps, guidance is in pretty good agreement. Expect highs in the mid to upper 50s.
Tonight: A couple of really big questions remain as to how much rain falls. The rain along the cold front is training along the front. The problem is, a lot of times when the rain bands make such slow progess eastward, they can essentially "rain themselves out" over one area. The GFS has a strange, but plausible, evolution, where it shows the rain falling apart as it heads towards CT, then picking up Atlc moisture and re-energizing over E CT. The NBM guidance does not really agree with this evolution, and has much more uniform totals, around an inch and a half for the entire state, with just a slow decay from W to E. This evolution kind of makes more sense. Either way, it will rain, heavy at times, mainly in the 2nd part of the night. I'll keep t-storms out of tonight's forecast, as that element of the storm will definitely lose steam before getting here. Winds should stay fairly gusty until dawn, so keep that in the fcst all night, with gusts to at least 30 MPH, possibly higher in heavier showers. As for temps, I'll go way above guidance and keep temps steady thru the night. There is no fropa during the night, and strong S winds, so no reason for temps to drop much. Expect temps to drop to around 50 with the onset of rain and then basically sit there.
Tomorrow: After some morning sun, showers and t-storms will redevelop. However, the main focus will be closer to the stalled low pressure system, i.e. west of the Hudson River. I still feel that some showers and storms will make it into CT, but I am having a hard time believing any get into Srn New London/Srn Middlesex Counties, so no showers will be included there. The further west, and away from water you go, the stronger and more widespread these storms will be. So I will include a chance of strong storms in the NW Hills (i.e. Nrn Fairfield and Litchfield). For the rest of the state, scattered showers and storms. As for temps, guidance is in excellent agreement, and I see no benefit in trying to make it any better. So highs should be 60 to 65 degrees.
Tomorrow Night/Sat: All this wx might be worth it if we get a nice weekend, and it appears a beautiful weekend is in store. For Saturday, expect plenty of sun, and pleasant temps. Guidance is in good agreement, so no major changes planned. Highs should be around 60 degrees, but the coolest areas will be along the S Coast, with a developing afternoon sea breeze.
Big questions revolve around Sunday's forecast. A developing mesoscale convective system (MCS) could have big impacts on the fcst for Sun. The GFS, first off, is much faster than everything, and also weaker. Weaker, in a sense, would be easier to predict, for two reasons. First, we wouldn't have convection ruining model fcsts. Secondly, it would be more spread out, so the entire area would get a general light rain. The ECMWF, on the other hand, is much stronger with this feature, and much slower. The GFS would occur Sun aftn, while the ECMWF would be more like early Mon morn. The ECMWF centers the action around NYC, which keeps anyone N of the Merritt Pkwy dry. A solution like the ECMWF would mean 1-3" of rain centered around a 40-mile wide area, with nothing N or S of there. Because of all this uncertainty, and the possibility for more sea breezes, I went several degrees below guidance on Sunday. There is just too much uncertainty to buy really warm temps yet. So Sun's temps for now are being kept the same as Sat: 60-65.
Not much going on for Mon or Tues. Both days should be pleasant, with reasonable temps,a bit below normal. For both days, guidance has been accepted pretty much as is, as there's usually no reason to deviate too much on those types of days, esp when said days are 4 and 5 days away. A sneaky little cold front moves thru Mon nite. It is moisture-starved, so don't expect any rain with it. But it will be about 5 deg cooler on Tues. So highs should be in the mid 60s Monday and near 60 Tuesday. Both days should be 3 to 5 degs colder in the NW Hills.
The next potential wx problem is Weds. A weak coastal low scoots to our S. Although the actual low pressure center appears fairly weak, there could be a good amt of overrunning moisture with it. In addition, models have been trending N with it. Obviously, as of now, the S coast is most favored. However, I wouldn't be surprised if this trends into an entire state rainfall. I went well below NBM temps, because of the trend N with the rain and the fact that this is not yet reflected in NBM guidance. This yields quite chilly temps for the time of year, with highs of only 50-55 expected!
Skies clear out Thurs. There is very strong cold air advection, relative to the time of year. For that reason, I undercut guidance temps by a couple degrees. Highs should only be in the mid to upper 50s, despite sun!
Looks like chilly wx continues right into the day 6-10 period. There could even be a few sleet/graupel showers over Mother's Day weekend, esp in the NW hills.
Now, let's take a graphic look at some systems slated to affect our area. I'll show tonight's rain and Sunday's potential. I'll post them as depicted by the GFS. Keep in mind, esp for the Sun night potential, that other guidance is still very different. Here is tonight's system. The wild card is all that moisture out in E PA and how exactly it affects our area.
Next, here is the Sunday potential. Keep in mind, this could end up N or S of where it is depicted. And most models do have heavier precip in the core of it.
Anyway, that's all for now... it was probably too much! Take care and stay safe!
-GP!
-GP!
