Moderators StretchCT Posted January 5 Moderators Share Posted January 5 12z EFI again showing unusual atmospheric conditions 1 Link to comment Share on other sites More sharing options...
Moderators StretchCT Posted January 6 Moderators Share Posted January 6 BOX disco “absurd 105k jet at 925mb.” Spoiler Latest suite of deterministic and ensemble model guidance are in good agreement for a robust low-pressure system to impact The Northeast Tuesday night into Wednesday. Unlike the system we will experience this weekend, this system is forecast to take an inland track which is likely to support an event that will be entirely rainfall. Though temperatures may be cold enough ahead of the storm to allow a brief front end thump of snowfall prior to a change to rain. Model guidance is hinting at exceptionally strong QG forcing for ascent with rapid height falls over the region. This combined with anomalously high moisture will set the stage for a significant rainfall event. 100 member LREF ensemble is already indicating a 30 to 60 percent chance of 2+ inches of rain in 24 hours over portions of RI and the CT River Valley. With a fresh snow pack in place, this may introduce some flood concerns along areas and river in streams. The multi-model hydrologic ensemble (MMEFS), is already indicating a 30 percent chance of several river gauges reaching flood stage next week. In addition to the rain/flood threat, this storm will be packing a dynamic punch with a very impressive wind field. The 12Z deterministic GFS is resolving an absurd 105 knot jet at 925 hPa over The Gulf of Maine at 12Z on Wednesday. Even if we take the more practical long term probabilistic approach, ensemble probabilities of 850 hPa winds exceeding 80 knots are 20 to 50 percent over the east coast and east coastal waters. Thus, we may be looking at a significant wind thread in addition to the rain/flooding threat. Furthermore, the strong southerly flow is likely to produce a storm surge that could introduce some coastal flood concerns to the south coast. We`re well outside of the time range of our surge models, so really know early predictions as of yet as coastal flood forecasts are heavily dependent on surge/high tide timing. We`ll be ironing out all the details as confidence in this forecast grows late this/weekend early next week. Link to comment Share on other sites More sharing options...
SnowloverSid Posted January 6 Share Posted January 6 Wednesday’s max in Binghamton has been raised from 40 to 46, only three degrees shy of the daily record high for January 10. It is the only sub-50 record max fin January, the other two being in early February. A 46-degree rain would leave the area with bare ground and mud— yuck. 1 Link to comment Share on other sites More sharing options...
Moderators StretchCT Posted January 6 Moderators Share Posted January 6 Max gusts from 12z gfs today -keep in mind it's in kts. 60 kts is 69mph. 1 Link to comment Share on other sites More sharing options...
Undertakerson2.0 Posted January 6 Share Posted January 6 So, where does this go? Link to comment Share on other sites More sharing options...
Moderators StretchCT Posted January 6 Moderators Share Posted January 6 (edited) We have an outlook for excessive rainfall/flash flooding from WPC Edited January 6 by StretchCT Link to comment Share on other sites More sharing options...
Moderators StretchCT Posted January 6 Moderators Share Posted January 6 (edited) Some qpf maps - up to and over 4.5" on some Edited January 6 by StretchCT 1 Link to comment Share on other sites More sharing options...
Moderators StretchCT Posted January 6 Moderators Share Posted January 6 5 minutes ago, Undertakerson2.0 said: So, where does this go? Passaic river Link to comment Share on other sites More sharing options...
Admin MaineJay Posted January 6 Admin Share Posted January 6 Incredible consistency on this. Surface temps around 40 indicate CAD likely holding enough to keep the worst winds at bay, but this is a bit closer for comfort. Link to comment Share on other sites More sharing options...
Admin MaineJay Posted January 6 Admin Share Posted January 6 Oops, I clicked back a frame, this is the same time stamp at the 850 winds. Mid 40s are more concerning. Link to comment Share on other sites More sharing options...
Admin MaineJay Posted January 6 Admin Share Posted January 6 These pink dots near the outer Banks and DelMarVa suggest we are at the extreme of climatology when it comes to wind gusts. 1 1 Link to comment Share on other sites More sharing options...
MainelySnow Posted January 7 Share Posted January 7 3 hours ago, MaineJay said: These pink dots near the outer Banks and DelMarVa suggest we are at the extreme of climatology when it comes to wind gusts. We do not need a repeat of 12/17. Without power for 4 days, was so glad to finally shut off the generator and have silence. We lost 3 80 ft pines and there are going to be a lot of trees that survived that storm, but barely, that won't withstand another, especially with saturated ground. Gonna be an interesting week... 3 1 Link to comment Share on other sites More sharing options...
Jon Snow Posted January 7 Share Posted January 7 Reading through the NWS forecast discussion from Blacksburg, Va, for this time peroid. I hope they know their attempts at a little humor here and there is appreciated. But wait; there`s more. Model forecast soundings from around the region are saturated (understatement) and the overall thermodynamic profile isn`t great. At all. However, strong wind fields will allow plenty of wind shear to be present. This could pose a risk of strong wind gusts with any convection. Right now, the location of the convective risk will be dependent on where a northward-moving warm front ultimately ends up. Right now, this risk appears to be much greater farther south of our area. But we will continue to monitor. 1 Link to comment Share on other sites More sharing options...
ionizer Posted January 7 Share Posted January 7 Can we start getting some wind model forecasts? Worried about the winds for central NJ coast. 1 Link to comment Share on other sites More sharing options...
Admin MaineJay Posted January 7 Admin Share Posted January 7 6 hours ago, ionizer said: Can we start getting some wind model forecasts? Worried about the winds for central NJ coast. I used Toms River. Looks like 25-35mph winds. Gusts are 50-60mph. I would note the operational is by far the weakest winds of the bunch. Hopefully the core of the winds are on the move, with little residence time over any one area. With such a strong low level jet, it certainly needs to be watched. 1 Link to comment Share on other sites More sharing options...
Admin MaineJay Posted January 7 Admin Share Posted January 7 GYX Quote LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... The focus on the long term remains fixed on the passage of a multi- hazard storm system crossing mid-week. While seasonable high pressure will start the week... conditions are expected to deteriorate Tuesday night through Wed with heavy rain, heavy snow, strong to damaging winds, and coastal inundation/erosion (see dedicated section below) all possible for the area. The broad model suite continues to show stronger than normal agreement on the general timeline and evolution of a low pressure system presently over the PacNW. The system is progged to drop through the Rockies on its way to the central and southern Plains, where it will begin to ingest significant moisture before shifting NE through the Ohio Valley... maturing in the process. The primary low pressure circulation is progged to cross well west of New England as it occludes, however a peripheral lobe of vorticity has consistently shown itself in model guidance and supports secondary triple point low development closer to the coast which throws a wrench in the otherwise ordinary inland-runner. The inland low promotes the development of a strong southeasterly LLJ around 80-90 kts which is the main driver of impacts centered on late Tuesday night into Wednesday. This is forecast to be a progressive system, with the jet crossing the area in relatively quick order... providing around a 6-9 hour period of impacts. Generally speaking, inland lows typically lead to greater inroads of warm and moist air through the low levels, which in turn supports a quicker changeover from snow to rain, strong to damaging wind potential, and a greater moisture influx leading to heavy rain. On the other hand the eastern component of the low pressure circulation will help to steady the CAD over portions of the interior for longer... leading to more snow and staving off the worst of the winds in those locations. The balance between these is the primary source of uncertainty WRT to the geographical distribution of impacts. For winds... model guidance has been steady and consistent in bringing 45-60 mph maximum wind gusts on average to coastal areas up to about the I-95 corridor. Similar gusts are projected to occur in the northwest-facing downslopes and adjacent valleys north of the mountains, from the upper Connecticut River Valley across through the Rangeley Lakes region and to Moosehead. Ultimately the strength of the jet will determine the high-end potential for winds, with some of the higher outlier solutions suggesting a few gusts near 70 mph... however for now confidence is greater in 45-60 mph winds. Areas most likely to remain sheltered from these stronger winds are the lakes and foothills regions south of the mountains, and down through the interior of southern New Hampshire owing to unfavorable boundary layer lapse rates. Though, when the system`s cold front crosses and mixing improves later in the day, southwesterly gusts to 25-35 mph or so will be possible anywhere. For QPF... models are fairly well clustered in the 1.5-2.5 inch range, with highest totals over the foothills and into the mountains as the jet ascends over the CAD and up the higher terrain. Higher QPF solutions are generally tied to warmer scenarios... since the overall model suite has generally trended a little cooler, I wouldn`t necessarily hang my hat on those higher solutions. Other than the terrain-enhancement, there is also a signal for an axis of higher precipitation totals over portions of the southern interior where moisture convergence is at its maximum. Given this is expected to be mostly rain here, and there will be around 0.75-1.0 inches of liquid equivalent on the ground from today`s snowfall, this could offer a pretty messy start to Wed with potential for flooding. This general threat of flooding due to rain over frozen grounds combined with snow melt is present for much of the interior, reflected in a marginal risk for excessive rainfall across all of Maine and most of New Hampshire... though we`ll likely be able to hone in on more specific locations as the forecast process progresses. Perhaps a bigger question is what ends up falling as rain vs what falls as snow. Most locations, besides the NH Seacoast and nearby areas, are forecast to start the event Tuesday evening as snow. As southeasterly flow ramps up upon the approach of the LLJ, the rain/snow line will make its way inland and northward... with most folks, at least in the urban corridor, experiencing rain when they wake up Wed morning. Further north in the CAD area, mostly confined to the higher elevations of northwestern Maine, snow is more likely to hold through the morning... with some mixed precipitation before an ultimate transition to rain. Though, some of these places especially toward the upper Kennebec basin may only see a brief period of rain before steady precipitation ends altogether. Snowfall totals thus run the gamut from hardly-anything (that melts by the time the sun rises)... to a sloppy couple-to-few inches over the interior, capped with a bout of rainfall... and up to a foot or more in the mountains, ending as lighter mixed or liquid precipitation. Similar to winds, the strength of forcing will determine the high end potential of snowfall totals, but for most people the timing of the transition to rain will determine snowfall totals with plenty of uncertainty left there. For all its potential hazards, this system is at least fairly fast- moving with the dry slot quickly cutting in behind the system during the afternoon and through the evening hours... bringing a quick end to steady precipitation and a westerly wind shift. The upper level low swings through the area afterward with mountain snow showers into Thursday before high pressure briefly builds in. Another storm approaches for the weekend but with widely varying solutions. 2 Link to comment Share on other sites More sharing options...
Wtkidz Posted January 7 Share Posted January 7 1 hour ago, MaineJay said: GYX Nice write up. 1 Link to comment Share on other sites More sharing options...
Wtkidz Posted January 7 Share Posted January 7 Not to be out done. LWX (Sterling) write up this way we cover the north and the south. 😜 Quote A powerful storm system is likely to impact the entire region Tuesday into Tuesday night. A highly amplified mid/upper trough over the Central Plains pushes eastward toward the MS Valley. A tremendous amount of upper diffluence will cause a surface low to develop and rapidly deepen as it tracks from the lee of the Rockies, across the Central Plains and central Great Lakes. A secondary wave of low pressure develops near the northern Gulf Coast, and is scooped up by the larger low to the north. As the entire complex pushes east, very strong WAA advection and an associated strong cold front are likely to bring significant impacts to our area. Temperatures ahead of this system shoot up to the 50s to low 60s. Wintry Mix: A residual cold air mass ahead of this system will likely result in a wintry mix of snow and freezing rain for areas west of US-15 Tuesday morning. Some snow accumulation and ice accretion are possible in the higher elevations west of the Blue Ridge. The strong synoptic forcing is going to help produce a quick burst of wintry precip, then strong WAA quickly transitions all p- type to rain by late morning. Heavy Rain: A period of moderate to heavy rain is likely to overspread the area Tuesday afternoon and evening, with the heaviest rain east of the Blue Ridge. Widespread rain amounts of 1.5-2.5" are currently forecast, though given the strong moisture flux, deep moist airmass, and strong diffluence, those totals could certainly end up higher. This heavy rainfall could lead to urban and river flooding. Strong Winds: The kinematic profile with this system is very concerning as all models indicate a strong LLJ overspreading the area east of the Blue Ridge. Current soundings from the GFS, ECMWF, and NAM12 all have 50-70KT at 925mb, and 70-90KT at 850mb. Generally, southerly wind events have a hard time mixing down fully in this area, but even if just half of that wind reaches the surface, it could result in numerous instances of wind damage. Over the waters, this means Gale conditions are likely, and could possibly approach storm force (gusts of 50KT or greater). Continue to monitor the progress of this system in the coming days. 3 Link to comment Share on other sites More sharing options...
Admin MaineJay Posted January 7 Admin Share Posted January 7 Stout LLJ Link to comment Share on other sites More sharing options...
Admin MaineJay Posted January 7 Admin Share Posted January 7 Never seen anything like this. First frame is hr 240, yeah, there's a little wiggle early, but this is one week of runs. Incredible consistency. 1 1 1 1 Link to comment Share on other sites More sharing options...
Moderators StretchCT Posted January 7 Moderators Share Posted January 7 25 minutes ago, MaineJay said: Never seen anything like this. First frame is hr 240, yeah, there's a little wiggle early, but this is one week of runs. Incredible consistency. Consistency between models too. Here's the latest qpf. The placement and amounts are generally all in line. Of course todays storm had that too at one point but didn't work out for me. 1 Link to comment Share on other sites More sharing options...
Moderators StretchCT Posted January 7 Moderators Share Posted January 7 Max gusts from latest runs. 1 1 Link to comment Share on other sites More sharing options...
Moderators StretchCT Posted January 7 Moderators Share Posted January 7 Even the NBM has gusts 40-60mph 1 Link to comment Share on other sites More sharing options...
JDClapper Posted January 7 Share Posted January 7 Looking through some early Tues AM 2m temps, dews, 700mb fronto .. does seem to be a legit chance at a quick 1-3" in the interior of PA and especially north on the front end of this one. I know it's not the main impact from this one (Rain/flooding/winds), but hey... could be dicey for an hour or two on the wintry side for some. 1 Link to comment Share on other sites More sharing options...
NotInKansasAnymore Posted January 7 Share Posted January 7 Watching this one carefully in Hunterdon County, NJ. I have 2-3 inches of very heavy, wet slush on the ground and 3+ inches of rain will make for a big mess here. The heavy rain right before Christmas led to school cancellations because our country roads all flood out. We also have a lot of sideways trees left over from Sandy - wet ground and high wind will cause a lot of outages. 2 Link to comment Share on other sites More sharing options...
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