wdrag

Need to keep monitoring the daily changes occurring in modeling aloft across North America, the first week of November. IF (when) a TC-Hurricane gets going near Cuba--- pretty sure it will adjust the upper atmosphere far away... There's already a fair amount of spaghetti showing sharp troughing in the USA first week of Nov. Where it ends up and the amplitude? Then, whether any tropical moisture or TC gets swept up the eastern USA, or as climo above shows...east-northeast out to sea away from FL... too soon to know but am wary of GEPS/EPS not showing much. I'll need to see the GEFS continue its increasing likelihood of a TC GOM-Caribbean near or just after Halloween, and increasing number GEFS members sharpening the trough near 80-85W the first week Nov. Yesterdays CPC words were attached to the graphic posted yesterday by purduewx on this page. Those words are: Recently, the anomalous upper-level divergence (convergence) increased over the Maritime Continent (Americas and Africa). Despite destructive interference between the MJO and the emerging weak La Nina during the next week, the GFS and ECMWF models are in good agreement and consistent that a moderate to strong MJO propagates eastward to the western Hemisphere. By early November, the MJO is predicted to shift east from the Americas to Africa and the Indian Ocean. Based on the strength of the MJO during the next three weeks, MJO composites for both favored tropical cyclone (TC) development and anomalous precipitation are a major prognostic tool in the weeks 2 and 3 outlook. A pair of tropical cyclones (Nadine and Oscar) formed over the Atlantic basin this past week. Nadine was a short-lived TC and Oscar rapidly became a hurricane as it tracked north of Hispaniola. The GFS and ECMWF ensemble members support a 40 to 60 percent chance of TC development across the Caribbean Sea from October 30 to November 5. Many of these ensemble members depict TC genesis occurring as early as October 29. Regardless of the exact timing, forecast confidence is high that another TC forms across the Caribbean Sea by the end of October. Model guidance is also depicting an elevated chance of a subtropical low pressure system or tropical cyclone forming at a higher latitude over the southwestern Atlantic. This would be consistent with climatology and thus a 20 to 40 percent chance is posted for this region during week-2. From November 6 to 12, a 20 to 40 percent chance of TC development is posed for the Caribbean Sea based on climatology and since the MJO is likely to maintain a favorable large-scale environment for a late season TC through at least mid-November. ---- CPC's 3PM updated D8-14is attached... this fits the concerns expressed by this group in these past two pages. So, until the westerlies prevail down to GA inside of D7 on the GEFS and it no longer argues for TC development, I keep the door open for anything happening eastern third of the USA the first week of November. Just need to be patient and if this risk shifts out to sea as climo suggests, then I'll admit it. We are in an abnormal pattern. I'll wait this out a few more days.

Barring stats presented by others here that differ, imo, the GFS is best at TC genesis. That said, the 00z/22 GEFS has a closed ridge aloft centered off the Carolinas at Halloween. You see the # of members of this 21 member ensemble with something (TC) going s of Cuba. My guess is that modeling will continue to accentuate the ridge aloft off the Carolinas with time beyond D10, and steer the potential TC west, before eventual N-NE. Beyond D10, GEFS and EPS differ (especially Nov 4-6) with the GEFS progressive westerly flow while the EPS lags and has "potential" for the trough lagging back around 85W. Climate is full of extremes... Milton-Helene combo have us in a serious short term drought here in the NY-Philly metro. Could it reverse to a very wet pattern here along the e Coast in Nov...aided by a TC? I don't anticipate a Sandy, but I do think a TC forms, and only my opinion, it seems to have FL potential and northward along the e coast, dependent on trough aloft timing. Modeling of mid-upper level troughs-ridges tends to mush out with the variant members... and often sharpens drastically from a D10-15 spaghetti outlook. Need a TC first, then let the modeling steering adjust and guide us. Worthy of monitoring.

I think the above is very well analyzed currently-future. It's all modeling but the modeling is improving it's corridors of interest beyond D5 (imo).

Agreed above... and I think the 12z/21 GEPS trends past 4 cycles is growing. EPS marginal. but imo, it's worth monitoring. My guess is NHC could begin a TWO mention around 10/23-24. Also fwiw... the TWO per the NHC naming of TC's. the TWO has been on the slow side (Milton through Oscar) ramping up probability concern once they have it in the system. Am aware of AMWX participant thinking the GEFS has a high bias on showing potential TC's (could that be mostly early season?). SST anoms still +normal except both sides of the southern FL peninsula . The light wind field mo∂eled at upper levels by the ensembles suggests to me the potential for a TC near or south of Cuba is favorable. Realizing that there are far more considerations, I leave it that. I tend to look at ballpark opportunity. Expert criteria may say no-go but for now I continue to monitor the GEFS in particular, until the GEFS loses it, if it does.

minor comment impression: looking back at least a week... I'm giving this (Nadine-Oscar) predictability to the GEFS as a win... other primary global models were imo lackluster. Looking ahead... Cuba-Bahamas-possibly an east coastal Fl threat around Oct 30-31. This time multiple model attempts.(00/20 EPS, GEPS, GEFS). Doubt this will disappear within big eastern USA ridge.

NOT October, but fwiw, the NOAA-CPC winter outlook is posted. Attached are a few changes in tools-products this cool season...as attached to their winter outlook just released today. Click for clarity.

NOAA-CPC just posted their winter outlook-official on Oct 17. Here are some of the primary attachments. What I noticed in recent trends, is they cooled it slightly in the ne USA, and also reduced the chance of above normal qpf in the Ohio Valley.

Commenting on modeling and verification: NHC verification of sustained wind fields may be biased slightly high (ONLY my opinion). That was what I was seeing when still in NWS at PHL-BOS (ret 2018)... and I think then it was in flight assessment that seemed to expand the wind field slightly. Regarding wind GUSTS for Milton: I tend to like the ECMWF and EPS (6 hr max wind gust ) seen on Pivotal Weather. These are a nice ballpark (for me) of what to expect... you can also ee the hourlies of the max gusts GFS/CMC etc. The HRRR was terribly low at 36-48 hours and I wasn't impressed with the RAP. Others may disagree, but what I like to do is remember advance notice max wind gusts (D1-5) and place my concerns in perspective with respect to different date storms, and then within the context of same event modeling. I, again my bias, but I thought the EC op for both Helene and Milton were pretty good... especially Milton picking up on DAB max wind gusts. SPC HREF did a nice job on mean and max rainfall. from 00z/9. Atached the 00z/9 48 hr MAX rainfall axis prediction, and the reality CoCoRaHs numbers (without the 18" St Pete official report). CoCoRaHs numbers are official for NWS use.

Will be interesting to see what happens late next weekend (Sunday 20th): GEFS has at least several members continue northward moving into GOM around the western ATLC ridge (noted your pgh 1 GEFS bias), whereas GEPS and EPS are comparatively benign, though EPS seems to be increasing slightly the past day of modeling. Plenty of time for GOM to recover positive SST anomaly where it cooled via Milton. Uncertainty for sure...

A couple of things bother me about data use: Poweroutage.us... not many media are aware, or I'm in error: The listing is meters without power. That equates to a larger number of people without power (the going relationship is multiple 2.5X, though may be a little high). Still, unless clarified otherwise, power outage map reflects meters out, but the number of people without power higher. I personally like the percentage of the state being without power better... in this case nearly 30% at peak outage yesterday. A lot has been made about the Number of TOR warnings issued for this event. While the data is still incomplete (storm data), I checked via IEM COW, preliminary verification 12z/9-12z/10... and give or take depending on your resources... in this 24 hour period there were 120 TOR warnings (MLB, MIA, TPA combined). My concern is only 37 verified as TOR's (so far). Again, when comparing days of TOR's and the various EF against the background historically (only the last 35 years since the 88D came into existence), we have amped up verification with better supporting documentation. I prefer tempering # of warnings (TOR's are a difficult hazard to verify) as a severity indicator and just going with the reality. No doubt it was a big day with killer storms from multiple hazards embedded within the excellent Milton tracking (cone) by NHC. I say the same thing about Extreme Wind Warnings: This is only a very recent addition (~2005) to our hazards.

From CPC yesterday (10/10/24) on the unfolding La Niña: This posted just I. case it impacts your predictions for snowfall at CP this winter, (ne USA). The IRI plume predicts a weak and a short duration La Niña, as indicated by the Niño-3.4 index values less than -0.5°C [Fig. 6]. The latest North American Multi-Model Ensemble (NMME) forecasts were warmer this month, but still predict a weak La Niña. As a result of the warmer predictions and the recent weakening of equatorial trade winds, the team still favors a weak event, but has lowered the chances of La Niña. A weaker La Niña implies that it would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance (e.g., CPC's seasonal outlooks). In summary, La Niña is favored to emerge in September-November (60% chance) and is expected to persist through January-March 2025 [Fig. 7].

Below sometime since about 1230Z... I didnt check the obs time specific. From MOE-Bob Hart extreme wind. KEYW: Key West, Key West Intl Arpt, FL, United States [47kt, 24m/s] KNQX: Key West, Naval Air Stn, FL, United States [44kt, 23m/s]

Manatee County FL 13000 meters without power. No storm report. Cause unknown.

fwiw...noticing much of the w coast of FL, NOS Tide gauges running nearly a foot above predicted, already.

Nothing to do with todays weather here... but in response to Helene flooding, Ben Noll produced this recent historical PW graphic, for future general reference. Presuming the overall ever warming world continues, these PW MAX values will increase. I already am on alert when PW exceeds 1.75", and occasionally we'll get up to 2.5 but a 3" for more than a few hours would be more than alarming. Here's the graphic... reliable resource. Just thought the share would be worthy to store away in the recesses of our references. Have an enjoyable two weeks up here.

Minor interest example: big forest fire in WY as seen in pix yesterday and the 06z/30 HRRR vertically integrated smoke, plus its modeled east and south spread by late Tuesday night. Click for clarity and see the legend info. Vertically integrated implies where coverage is heavy...hazy sunshine... but does not reflect near surface smoke which is expected to be confined to WY and possibly w Dakoas.

What about the Hurricane of 38 (New England)?

I'm interested in knowing which two models performed best on track from FF-GA, and intensity? I dont need timing assessment. There's quite a few pages for me to wade through. Is there any general consensus. Thanks, Walt

Took the liberty to share the WeatherBell winter snowfall outlook, and the link for more details. https://www.weatherbell.com/a-look-at-winter

Added 9/21/24 from CPC - the Sept 19 updated 3 mo outlook: Looks like an OH or Tennessee Valley storm track nearby... everyone on this post is pretty conservative for the winter snowfall (so far). Good timing of a storm and cold enough vertical profile would be welcomed by snow lovers... I'm not giving up yet. CPC Sept 19 DJF below:

I just took a look at the ECMWF ensemble predictions through JFM2025 northern hemisphere. Depressing if it verifies. Above normal temps coast-coast with best chance below normal near the Canadian border of the ne USA, and a dry start turning to a normal or wetter than normal JFM, as ensembled around Sept 1. https://charts.ecmwf.int/?facets={"Product type"%3A[]%2C"Parameters"%3A[]%2C"Range"%3A["Long (Months)"]%2C"Type"%3A["Forecasts"]}

I will add CPC seasonal outlook updates around 9/21 and then the big one for CPC around Oct 17. Here's from the ACCU-WEATHER supported OFA... a general temperate milder than normal winter in the USA. For our area: Region 2: Atlantic Corridor This swath of land along the East Coast covers portions of seven states, including New York, Pennsylvania, and Virginia, as well as major cities from Boston and NYC to Washington, D.C., and Richmond. How Cold Will Winter Be? Not bad! Temperatures will be average to slightly above average during winter (though 2% colder than average during February). The region will also experience shots of cold in mid-December, early and late January, and late February. Will There Be Snow? Precipitation will be slightly below normal this winter. In this region, snowfall will be below normal in the north and above normal in the south. The most snow is expected to arrive in late December and late February.

Better than last 3 seasons eh? I tend to agree w you on below normal but a little better than the past seasons but my take is not through stats/patterns.--just a guess. One of the factors I failed to mention in the topic introduction--- marine above normal cool season warmth which has probably played a role in more mixed-rain in our subforum, instead of predominant snow.

Regarding the coming winter snowfall. As of August, 2024, CPC had us above normal temp for DJF, and near the storm track - indeterminate regarding above or below normal precipitation, as apparently we progress into a La Niña per their headlines-guidance. Attached are the SEASONAL (Nov 1-March 31) snowfalls in CP (with usual measuring uncertainties found in many datasets not directly associated with NWS office measurements). Also attached is the latest ENTIRE seasonal snowfall per official climate assessment, with 0.5" outside the Nov 1-March 31 primary window. I think we can acknowledge from the datasets presented, that a CP December of above normal snowfall bodes well for an above normal winter of snowfall. I have checked the regional boards adjacent our NYC subforum and have only seen winter outlook discussion on the New England subforum. Posts don't have to be many pages as I think the longer they are, the greater the uncertainty-caveats. However, anything posted in my opinion should be self assessed around March 31, 2025. I'll venture to say anything between 25-35" snowfall is near normal for CP (2013-18 seasons ending March 31) but others will probably disagree. The idea here... it's been awhile (2020-21 season) for an above normal seasonal snowfall in CP and generally in the NYC subforum (Wantage NJ 60" that winter) Seasonal forecasting specific parameters is not easy and statistically less reliable than a 1-3 week period from (T0), the moment of issuance.

Minor good news (from my perspective) regarding the NAM: Due to the fact warm season mesoscale modeling is not showing major rapid improvements in potential qpf, the NAM retirement may be delayed due to the lack of an adequate replacement.