RU848789

Really liked Upton's discussion today... Attention then turns to the second half of the weekend. While there is a general agreement on a potential storm system to pass near the region Saturday night and Sunday, confidence is very low on any specific impacts including precipitation types, precip amounts, and winds. The exact timing is uncertain, but appears to occur sometime Saturday night into Sunday/Sunday night. The 12z deterministic and ensemble suite includes scenarios that give the area an all snow event, a mixed precipitation event, or one that has at least the southern half of the area in plain rain with potential of wintry precip inland. There are also solutions that indicate the system passing far enough south that little to no precip occurs in the CWA. It is important to stress that any of these solutions are possible, but we cannot say with any confidence which one will occur. The model guidance is likely to waiver many times in the next several days as the main southern stream energy is still over the north central Pacific. The energy looks to reach the western US Tuesday night into Wednesday. The evolution of the northern stream over southern Canada is also important to the outcome from this potential system. The NBM does indicate a respectable 70 percent chance of measurable precip (greater than 0.01") during time frame, and about a 50 percent chance of greater than 0.25". Deciding to Cap PoPs off at 50 percent for now given that it is still just under a week out. Precipitation types will be fine tuned as models converge and forecast confidence increases.

Faster system, precip arrives after dark, plenty of snow, verbatim. Significant snow on the table is all I'm looking for at this point.

6 pages for a storm that's 6+ days out in an extremely fragile setup, which could easily miss us or just rain on us (along 95), tells us how snow-starved we all are. I just like the fact that there's some chance of getting decent snow and something to track for a change. We are certainly due for a little luck after watching every threat fizzle last winter and we haven't even had any real threats so far this winter.

The NWS Philly cancelled the wind advisory as of about 10 pm, as they're not seeing the high winds aloft mixing down to the surface as much as expected. There will still be gusts to 30-40 mph, but those are below advisory criteria. Lots of rain still to come, especially along and SE of 95. There is a strong low level jet, generally 40 to 50 kt, along the New Jersey coast, but the strongest winds are not mixing down given how warm the ocean is. Surface obs near the coast are generally reporting 30 to 35 mph gusts. Will go ahead and cancel the Wind Advisory, these winds are below Wind Advisory criteria.

Latest NAM still wants to bring accumulating snow to the 95 corridor, but it stands alone, as no other models show more than a dusting to an inch or so outside of areas well N/W of 95 with only areas like higher elevations of the Poconos, Sussex and interior SENY getting more than an inch. Would be a coup if it verified. I'll be happy with mood flakes and maybe a dusting in the Edison area.

I understand it's unlikely, but at some point, with both the NAM and GFS showing several inches of snow down through the 95 corridor, (except for the perfect snowhole over NYC metro on the GFS) one has to wonder if there's some chance they're on to something and maybe we could get some white stuff. Stranger things have happened...

Had a few flurries at Allaire State Park in Monmouth County around noon (was playing disc golf there)... As an aside, CPK hit 30F on 11/25 its first temp AOB 32F, but I don't recall any freeze watches/warnings - did I miss that somehow?

Thanks, did know that, but was more looking for hourly output from the globals and NAM/RDPS, even though the higher resolution convection allowing versions of those (NAM3K and HRDPS) are available hourly, as you noted - but I've observed that sometimes the lower resolution versions do better with non-convective systems like this one. And TT does have the HRDPS, which is hourly. Would also be nice to have IBM's/TWC's GRAF model output somewhere, which supposedly has very good accuracy scores, but I haven't seen it available anywhere (some media outlets use it though) to the public.

No offense, but for me and thousands of others, the primary issue is the RU game in Piscataway, with tailgating from maybe 7 am to noon, which looks mostly dry on most models (maybe 0.05-0.1" before noon), but then the steady rains look to move in sometime in the 12-2 pm timeframe on most models (kickoff is noon), so the timing is really critical for fans and there is definitely significant variability on QPF starting around 2 pm, with some models showing 0.1-0.2" from 2-5 pm while others show closer to 0.3-0.4". My one big question for folks is where can I find hourly precip forecasts from the models (even if it's a pay site)? Pivotal premium only has 3 hr increments on some models and 6 hr increments on others and I'd love to see finer output. i know I can get hourly once the HRRR and RAP are in range, but it would be nice to have that, too for the globals and NAM/RDPS. Thanks...

Models keep bouncing around for total event QPF, but narrowing down on 1/2-1" from maybe 78 to 84 and 1-1.5" from 78 down through SNJ/SEPA. NWS calling for a general 1-2" in most locations, including NYC, so they're a bit more bullish on the rain. For me the issue is the RU game in Piscataway, with tailgating from maybe 7 am to noon, which looks mostly dry on most models, but then the steady rains look to move in sometime in the 12-2 pm timeframe on most models (kickoff is noon), so the timing is really critical for fans and there is definitely significant variability on QPF starting around noon, with some models (6Z NAM and RDPS) showing no rain through 2 pm and very little rain through 5 pm, even, while other models are showing 0.1-0.2" through 2 pm and maybe 1/4-1/2" total through 5 pm. The NWS has about 1/4" through 2 pm and almost an inch from 2 pm to 8 pm in their hourly graphic. For most people the difference between 0.1" and 0.3" of rain is inconsequential, but not for fans out in the open. Crossing fingers for the NAM/RDPS to be right.

As the rainfall graphic below shows, the amount of rain east of the Hudson in NYC/SENY and just off the NJ coast (except some very heavy rains at the immediate coast and just into NJ across from the Hudson) has been incredible, with the following highlights from the story linked below. There will likely be parts of that area that get 7-9" of rain, which is 2 months worth in one day. https://www.cnn.com/2023/09/29/weather/new-york-city-northeast-rain-flood-forecast-climate-friday/index.html In Brooklyn: A month’s worth of rain, up to 4.5 inches, fell in only 3 hours on Friday morning, according to National Weather Service data. This three-hour rainfall total is only expected about once every 100 years in Brooklyn, according to NOAA estimates. In Manhattan: Nearly 2 inches of rain fell in one hour in Central Park, the second-wettest hour there in 80 years. More than 5 inches of rain have fallen there so far. In Queens: It’s a top-10 wettest day at John F. Kennedy International Airport, where more than 4 inches of rain has fallen since midnight.

Yeah, the Euro ensemble mean shifted west about 60 miles from 12Z (but 0Z last night was even about 60 miles further west), with obviously more members hitting west of Maine.

12Z Euro landfall about 100 miles NE of 0Z, so it's looking like 0Z was a bit of a blip and not a trend...

NHC is not ready to jump onto the Euro solution at 0Z, probably because the gap has tightened between the other globals and the Euro (and we have improved hurricane models like the HAFS-B) since Sandy's coup in 2012, plus the Euro has stumbled for a few recent storms. Here's what they said in their latest discussion: The latest NHC track was a compromise between the 6z GEFS and ECMWF ensembles in the days 4/5 time frame, as it is still too early to know if any leftward bend will occur as Lee approaches North America.

The 6Z Euro ensembles looked like they moved back east somewhat relative to last night's 0Z run, but as far as I know the 6Z operational only goes out to 90 hours, so I'm guessing we'll have to wait for 12Z to see if 0Z was a blip or not. Would certainly be interesting if the Euro is on to a westward shift about 5 days out vs. the other models, paralleling, somewhat, the Euro sniffing out Sandy's NW hook into NJ (although that was a monster coup, 7 days out). https://www.weathernerds.org/tc_guidance/storm.html?tcid=AL13

That's New Brunswick, CA, between far east Maine and SW Nova Scotia and the storm is predicted to go from 981 mbar in the frame below to 989 at landfall in far SW Nova Scotia (if one assumes this being correct 6 days out). I've seen 970-980 at or very close to landfall, which implies a Cat 1/2 system (likely transitioning to extratropical), based on the SS scale. A pretty big deal for that neck of the woods. Anyone from Cape Cod to Newfoundland should be prepared.

True. The Euro was the westernmost model at landfall at 12Z and now it's the easternmost at 0Z, looking a lot like the CMC at 12Z, which also didn't quite make it to even hitting Canada, while the 0Z CMC hits downeast Maine like the 12Z Euro did - they basically flip-flopped. While the GFS moved from a Newfoundland landfall to a Nova Scotia landfall. I know op runs are not to be trusted at this range, but it's fun to look at them...

The Euro is also about 18-24 hours "slower" than the GFS/CMC - lots to resolve before we really have a handle on this one...

Cat 5... BULLETIN Hurricane Lee Advisory Number 11 NWS National Hurricane Center Miami FL AL132023 1100 PM AST Thu Sep 07 2023 ...LEE BECOMES A CATEGORY 5 HURRICANE... ...DANGEROUS BEACH CONDITIONS EXPECTED TO DEVELOP AROUND THE WESTERN ATLANTIC THROUGH EARLY NEXT WEEK... SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...17.3N 52.4W ABOUT 705 MI...1135 KM E OF THE NORTHERN LEEWARD ISLANDS MAXIMUM SUSTAINED WINDS...160 MPH...260 KM/H PRESENT MOVEMENT...WNW OR 295 DEGREES AT 14 MPH...22 KM/H MINIMUM CENTRAL PRESSURE...928 MB...27.41 INCHES

Good points, but on the last one, I'd say it's not an apples to apples comparison, as most winter storms, at least in the NE US, aren't fully formed entities that move for several days across the country, as they're usually the product of multiple pieces of energy coming together to form the ultimate winter storm, usually less than one day before the wintry weather begins. Hurricanes, by contrast, are mostly fully formed storms (at least once named) subject to a variety of steering factors, but I'd argue they're easier to predict 5 days in advance, as we've often seen with many tropical systems (not all, of course).

Good memory! Sam was forecast to hit 115 mph at 120 hrs... https://www.nhc.noaa.gov/archive/2021/al18/al182021.discus.001.shtml?

I said the exact same thing on FB when the first advisory came out and I've been tracking storms for a long time - maybe it has happened, but I don't recall it. Just looked back at a few of the big ones over the last 25 years (the ones on the NHC archive page) and Ida was the closest, with 110 mph predicted at 72 hours in the first advisory.

Question for you. In theory, wind gusts greater than 65 mph are usually needed to uproot mature trees and there was a report of 30 trees down on HHI, so I assume then, that at least at times and maybe in isolated locations, winds probably gusted over 65 mph, even if those speeds weren't recorded at the few stations on the island. So, was wondering what the max recorded gusts were on HHI (the public info statement from the NWS office doesn't show any gusts on HHI over 40 mph, unless I'm not aware of place names). Any input on that? Edit: looking at the PNS for the area, there were gusts of 69 mph on Tybee Island about 7 miles SW of HHI, 66 mph in Beaufort about 10 miles NE of HHI and 64 mph in Calibogue Sound about 1-2 miles SW of HHI. I just find it hard to believe that some places on HHI wouldn't have had 60+ mph gusts given reports of gusts that high surrounding the island, despite the reports of only ~35 mph gusts - looks more like the vagaries of wind variability and maybe instrument issues on HHI stations. https://forecast.weather.gov/product.php?site=NWS&issuedby=CHS&product=PNS&format=CI&version=1&glossary=1 https://www.wtoc.com/2023/08/31/not...island-residents-grateful-low-impacts-idalia/https://www.weather.gov/media/pqr/wind/wind.pdf

Looks like the beach just SSW of Perry is going to be ground zero for landfall in about 90 minutes, given the NNE motion at 18 mph with 125 mph winds, as the storm weakened a touch... Hurricane Idalia Tropical Cyclone Update NWS National Hurricane Center Miami FL AL102023 700 AM EDT Wed Aug 30 2023 ...CATASTROPHIC STORM SURGE AND DESTRUCTIVE WINDS OCCURRING IN THE FLORIDA BIG BEND REGION... ...7 AM POSITION UPDATE... Radar and Air Force Reserve Hurricane Hunter aircraft data indicate that an eyewall replacement cycle has begun. Idalia's maximum sustained winds are now estimated near 125 mph (205 km/h) with higher gusts. This change in wind speed does not diminish the threat of catastrophic storm surge and damaging winds. The estimated minimum pressure indicated by Air Force Reserve Hurricane Hunter aircraft data is 947 mb (27.96 inches). SUMMARY OF 700 AM EDT...1100 UTC...INFORMATION ---------------------------------------------- LOCATION...29.6N 83.8W ABOUT 55 MI...90 KM NW OF CEDAR KEY FLORIDA ABOUT 65 MI...105 KM SSE OF TALLAHASSEE FLORIDA MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H PRESENT MOVEMENT...NNE OR 20 DEGREES AT 18 MPH...30 KM/H MINIMUM CENTRAL PRESSURE...947 MB...27.96 INCHES

Just a 110C+ gradient from top to bottom, lol...