This week's forecast, aside from tonight into tomorrow, is not very straightforward at all, as it hinges upon the evolution of a cutoff low that will cutoff somewhere over the Eastern United States and exactly where will have drastic differences in our weather. Unfortunately, models are not in very good agreement.
Currently: The first focus of this forecast is a cutoff low, currently over the Lehigh Valley. This will be the focal point for a round of showers and t-storms later on.
Mesoscale Update: A Flash Flood Warning has just been issued for the Eastern Boros of NYC, as well as adjoining Western Long Island. This area of heavy showers and t-storms should head into Wrn and Central CT in the next couple hours.
Rest of today/tonight: An area of showers and thunderstorms should move through the state beginning soon. Any t-storms could contain heavy downpours and strong & gusty winds, but we are not expecting an outbreak of severe wx. All the activity should be outta the state, even the far Ern sxns, by midnite. As for temps, guidance will be closely followed, since I see no reason not to. So xpct low temps of 60-65.
Tomorrow: Warm but much drier behind the cold front. With full sun and a downsloping component to the wind, I have decided to go a couple degrees above guidance. So expect high temps of 80-85.
Tomorrow Night/Sat: Confidence in the overall forecast begins decreasing here, but Saturday will probably be a good day, weatherwise. I'm not going to mention any precipitation for Sat, but it is interesting to note that the NBM gets measurable right up to about NYC. So I suspect it could be cloudier than current guidance advertises, and I'll lean fcst that way. Because of this, I'll go just a smidge under guidance temps. Highs shud be in the mid 70s.
Long Term: I have, quite possibly, the lowest confidence in the long term forecast than I've had in recent memory. Models had been trending north and wetter with the cutoff low, then the 12Z GFS came out and went way south, but still eventually gets some moisture up this far, but we're talking Thu instead of Sun if it's right. When I went to check the 12Z GGEM, it is not avail on any sites I use. The 12Z ECMWF is not ready for another half hr. I might updt this sxn when the ECWMF runs. But for now, the fcst will be based on an examination of the GFS w/NBM guidance, which incorporates other guidance suites and ens guidance.
Glancing at the NBM, it actually seems close to the GFS. So for now, I'll keep measurable precipitation S of the state until Thursday. However, it should be noted, esp for the S coast, that measurable pcpn is not far away any given day and a small change in modeling would result in a much rainier fcst. Either way, ti shud be a cloudy and coolish week, and obviously much cooler if the cutoff low is a bit further N.
Starting with Sunday, I'll go close to guidance, maybe a tweak up here and there. Expect highs of 70-75.
For Monday, guidance inches ever so closer with precipitation. I think it may not be far enough N. Based on this, a strong onshore flow, and overcast skies whether it rains or not, I'll go a few degs below guidance. So look for highs only around 70.
For Tuesday, similar to Monday, I have a sneaky suspicion that steadier precipitation may creep in. Once again, I'll go a few degs below guidance. Xpct similar temps to those of Mon, maybe a deg warmer.
For Wednesday, even the GFS has precipitation knocking on the door. So I'll bring at least a little precip into most of the state, as my methodology this entire fcst pckg has been to go about 50 miles N of where the GFS has it. Could even be a brief tstorm along the S coast. Again I'll go under guidance by a few degs. Xpct high temps in the low 70s.
For Thursday, nearly all guidance has measurable precipitation getting into the state, although the precipitation mode shifts from stratiform to convective, which would mean "less steady" precipitation. With the lack of confidence in the overall details of this part of the fcst, it would be futile to try to time when this would occur. But right now, given that most modeling has this happening during the day, I'll lower guidance temps. So xpct highs in the mid 70s.
Update on the 12Z ECMWF: It is in and is even drier than the GFS, not even getting precipitation in here Thursday. It's a cloudy, cool, onshore flow look, but with no precip. There are a few showers Tues along the NY/PA border, so we'll see if we can squeeze anything out of that. It's a fluid situation, and could easily chg agn next run, but this is another reflection of being stuck in a repetitive pattern w/o much chg in sight.
Looking into the longer range, the GFS once again tries to produce big heat beginning around day 8-9. I would caution against that, since it seems to never move up in time. We'll have our very warm to hot days on occasion, but I wouldn't go predicting a big hot pattern until I see more evidence of it than a day 9 GFS map.
Now, let's take a graphical look at some of the systems slated to affect our area in the coming week. I really don't know what to post here. Tonight's sys is extremely near-term now and the cutoff is going to be meandering all week. I guess I'll post a GFS map and an ECMWF map for comparison purposes.
In this first image, the GFS, valid next Thursday, shows precipitation being strung out between two highs and a very weak low, what is left of our cutoff, near the Delmarva peninsula.
Currently: The first focus of this forecast is a cutoff low, currently over the Lehigh Valley. This will be the focal point for a round of showers and t-storms later on.
Mesoscale Update: A Flash Flood Warning has just been issued for the Eastern Boros of NYC, as well as adjoining Western Long Island. This area of heavy showers and t-storms should head into Wrn and Central CT in the next couple hours.
Rest of today/tonight: An area of showers and thunderstorms should move through the state beginning soon. Any t-storms could contain heavy downpours and strong & gusty winds, but we are not expecting an outbreak of severe wx. All the activity should be outta the state, even the far Ern sxns, by midnite. As for temps, guidance will be closely followed, since I see no reason not to. So xpct low temps of 60-65.
Tomorrow: Warm but much drier behind the cold front. With full sun and a downsloping component to the wind, I have decided to go a couple degrees above guidance. So expect high temps of 80-85.
Tomorrow Night/Sat: Confidence in the overall forecast begins decreasing here, but Saturday will probably be a good day, weatherwise. I'm not going to mention any precipitation for Sat, but it is interesting to note that the NBM gets measurable right up to about NYC. So I suspect it could be cloudier than current guidance advertises, and I'll lean fcst that way. Because of this, I'll go just a smidge under guidance temps. Highs shud be in the mid 70s.
Long Term: I have, quite possibly, the lowest confidence in the long term forecast than I've had in recent memory. Models had been trending north and wetter with the cutoff low, then the 12Z GFS came out and went way south, but still eventually gets some moisture up this far, but we're talking Thu instead of Sun if it's right. When I went to check the 12Z GGEM, it is not avail on any sites I use. The 12Z ECMWF is not ready for another half hr. I might updt this sxn when the ECWMF runs. But for now, the fcst will be based on an examination of the GFS w/NBM guidance, which incorporates other guidance suites and ens guidance.
Glancing at the NBM, it actually seems close to the GFS. So for now, I'll keep measurable precipitation S of the state until Thursday. However, it should be noted, esp for the S coast, that measurable pcpn is not far away any given day and a small change in modeling would result in a much rainier fcst. Either way, ti shud be a cloudy and coolish week, and obviously much cooler if the cutoff low is a bit further N.
Starting with Sunday, I'll go close to guidance, maybe a tweak up here and there. Expect highs of 70-75.
For Monday, guidance inches ever so closer with precipitation. I think it may not be far enough N. Based on this, a strong onshore flow, and overcast skies whether it rains or not, I'll go a few degs below guidance. So look for highs only around 70.
For Tuesday, similar to Monday, I have a sneaky suspicion that steadier precipitation may creep in. Once again, I'll go a few degs below guidance. Xpct similar temps to those of Mon, maybe a deg warmer.
For Wednesday, even the GFS has precipitation knocking on the door. So I'll bring at least a little precip into most of the state, as my methodology this entire fcst pckg has been to go about 50 miles N of where the GFS has it. Could even be a brief tstorm along the S coast. Again I'll go under guidance by a few degs. Xpct high temps in the low 70s.
For Thursday, nearly all guidance has measurable precipitation getting into the state, although the precipitation mode shifts from stratiform to convective, which would mean "less steady" precipitation. With the lack of confidence in the overall details of this part of the fcst, it would be futile to try to time when this would occur. But right now, given that most modeling has this happening during the day, I'll lower guidance temps. So xpct highs in the mid 70s.
Update on the 12Z ECMWF: It is in and is even drier than the GFS, not even getting precipitation in here Thursday. It's a cloudy, cool, onshore flow look, but with no precip. There are a few showers Tues along the NY/PA border, so we'll see if we can squeeze anything out of that. It's a fluid situation, and could easily chg agn next run, but this is another reflection of being stuck in a repetitive pattern w/o much chg in sight.
Looking into the longer range, the GFS once again tries to produce big heat beginning around day 8-9. I would caution against that, since it seems to never move up in time. We'll have our very warm to hot days on occasion, but I wouldn't go predicting a big hot pattern until I see more evidence of it than a day 9 GFS map.
Now, let's take a graphical look at some of the systems slated to affect our area in the coming week. I really don't know what to post here. Tonight's sys is extremely near-term now and the cutoff is going to be meandering all week. I guess I'll post a GFS map and an ECMWF map for comparison purposes.
In this first image, the GFS, valid next Thursday, shows precipitation being strung out between two highs and a very weak low, what is left of our cutoff, near the Delmarva peninsula.
On the next image, the ECWMF has the low a bit stronger, but much further south, down by Hatteras. As a result, the blob of precip that the GFS has affecting our area is down off the Delmarva. Meteorologically, it's curious that the high posn on the ECMWF is actually more conducive of bringing the low further N, yet the GFS has the low further N. This illustrates my lack of confidence durg this pd quite well, and I am fairly confident tda/s soln is not the final one.
Anyway, that's all for now, I'll see you again next week! Stay safe!
-GP!
-GP!
