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PREFACE Operational model support is important, what do you think? If you say yes, perhaps you will be thinking now that it´s too much of gamble and waste of time and energy to start a thread for a possible storm 14 to 16 days out, with basically zero, or perhaps zero operational guidance support. If you think it´s not important, then perhaps you are thinking that this should be an interesting endeavor, worthy of the time and energy used. Ok. So, let´s continue, shall we? There´s a chance, possibility that a storm may form and grace the region with its blessed weather. All rain? All snow? A mix? Impossible to know. And honestly, there´s the no storm outcome as well. Having that in mind, let us see what we can get from this thread´s time frame only using teleconnections, EPS ensemble data, BSR and a couple of ESRL/PSD products. SUMMARY There exists the possibility during this time frame for a developing area of lower pressures on the East coast (inland or offshore), coming from the eastern GOMEX and SE CONUS area. Another possibility of an area of lower pressures could be in and around the Ohio and Tennessee valleys tracking eastward towards the east coast and ejecting over the Atlantic ocean from somewhere in the Mid-Atlantic region. Both areas of lower pressures could impact the thread´s region with some kind of weather. It´s impossible to exact if this possible storm would track inland, tucked to the coast, just offshore, or be a near miss, in the case of a possible SE CONUS genesis. As for the Ohio and Tennessee valleys possible area of lower pressures, the track is also uncertain, obviously. It may track too far north over NJ, father south or even cut through western NY. What should be noted is that we may have a storm to deal with, as the Holydays near. The data used to try to give some sense of support to this possibility, include, as aforementioned, teleconnections (AO, NAO, EPO, and PNA) from various different sources which include ESRL/PSD, GEFS, EPS and EPS 46 days), the BSR and other ERSL/PSD products. Below, I have illustrated in a simplistic and basic way, the general track areas for the lower pressures that could develop, as described in this summary. Please, take a look: On the next page, we will cover the previously supportive or not so much, mentioned data with images. Let´s start with the BSR. Looking at both the 500mb and surface depictions, there´s seems to be little support for a storm during this time frame, aside from a more noteworthy signal one day earlier on the 18th of December. Perhaps this could be a case in which a storm is delayed or could track in and around the coastal plain. However, acknowledging the BSR data shown for this time frame alone, a storm should cut through western NY. 500mb Surface So, support for a storm exists, but not the kind of storm most would want. Now on to a couple of ESRL/PSD products: These do show some support, as there seems that a trough will be digging and moving towards the east coast. The magnitude of the trough (how amplified and strong), of course, cannot be set now. Ensemble Mean 500mb Height Sea Level Pressure / 1000-500mb Thickness Hence, there is support for a storm as well, albeit, it may not be a powerfully amplified trough and flow. Now we get to the teleconnections from various different sources. They include the AO, EPO, NAO, and PNA. Some of them are not favorable, others are while some are in that highly regarded transition period. First off, we will check the AO. EPS 46 Days EPS GEFS All sources indicate a negative AO. Both the EPS 46 days and the EPS, show the AO closer to neutrality but does not quite make a transition. Negative AO bodes well for colder temperatures over the eastern CONUS. Being that the values are not that negative, it´s possible that the cold air, won´t be as deep or strong. Now, a look at the EPO. EPS 46 Days EPS GEFS All source indicate a positive EPO. They show small positive values and approaching neutrality. However, the do not quite start making the transition. Negative EPO helps keep the eastern CONUS colder. So, this kind of EPO along with the AO, may be saying that there should be cold air in place, but not strong in nature. Now, we check the NAO. EPS 46 Days EPS GEFS All sources indicate a negative NAO transitioning to neutrality and perhaps actually going into positive territory as can be seen on the EPS 46 days data. Negative NAOs support blocking of some sort. A transitioning NAO period is usually good for east coast storms. Now, we get to the PNA. EPS 46 Days EPS GEFS All sources indicate a positive PNA. A positive PNA means ridging over the western US, which in turn helps troughs get established over the eastern CONUS. Now to finalize the teleconnections, below please see the ESRL/PSD. Not quite in range, but we can see that PNA is quite positive, beneficial. The NAO going neutral, perhaps transitioning to negative. If so, it´s beneficial. And the EPO rather positive, not beneficial. In case it gets to neutral or transitions to negative by the time in discussion, that then would be a plus. In short, all in all, we have some good indications that a storm could be in the region during this time frame. And considering all the data discussed, in case a storm that brings snow to the eastern seaboard comes, we should not be surprised. At the very least, we will learn more once again. Whenever you feel the time has come, please join the discussion and possible tracking. Remember, there´s no model support as of now. Have fun! NOTE: The thread date and title will most likely need to be adjusted as we get near the time frame.
Introduction & Overall setup Hello everyone! By the time the possible event for this thread arrives, the region may have gone through the rains of a couple of Great Lakes cutter storms, or least warmer storms. As a result, some of you may be thinking to yourselves, where is the sleet. the snow? This thread is the platform to be used as an attempt to foment discussion, with the hope that answers, tracking, and analysis may lay credence to the possibility of a storm evolving and affecting the Mid-Atlantic and Northeast regions, perhaps with wintry precipitation. On this thread´s opener post, we will take a look at a plethora of data in the form of images, that indicate, or at least hint at the possibility of a storm developing for the region. The data will be used as support to give weight to the thread and its idea as well as act as a foundation to the exchange of ideas and points of view on how this event may unfold. As is customary, the data presented my directly or indirectly support the envisioned weather event. For the last 4 days or so, observations made on many different sources of information, such as teleconnections, BSR, EPS Control MSLP output, EPS Mean H5 anomaly, EPS Mean 24-hour precipitation, CPC 8-14 day outlook, precipitation analogs, and many different NCEP GEFS and ESRL/PSD output, were very informative and as a result, led to this thread as a way to promote debate on this possible event. An overall look at the aforementioned data listed in the previous paragraph led me to formulate the illustration below as a mere description of this possible weather event. Please continue on to the next pages to see many different data observed for this event. BSR Depiction Surface representation signal does not look not that impressive. H5 signal is somewhat more promising. Surface: H5: NCEP Ensemble Mean outputs Looking at the images below, it´s possible to interpret that some kind of a progressive to a somewhat deeper storm may arise. MSLP / 1000-500mb THK North America 500mb Northern Hemisphere 500mb Precipitation location aspect and 850mb temperatures give us some hint that moisture could be available together with colder H85 temperatures. Precipitation & Standard Deviation 850mb Temperature Anomaly 850mb Normalized Anomaly ESRL/PSD products outputs: A different perspective given by the PSD outputs. But the same idea though, a possibility of a progressive to a somewhat deeper storm. SLP/1000-500mb thickness North America H5 heights Same idea as well, possible moisture available along with colder 850mb temperatures. 850MB Temperature Anomaly Precipitation, Mean & Standard Deviation Teleconnections: Teleconnection signals, for the most part, appear to be indicative of the idea of a progressive storm given unfavorable negative PNA state. However, given the transitioning state of some of the teleconnections more or less during this time frame, one could not throw out a somewhat more robust storm. Please see below ESRL/PSD, GEFS and EPS 46 days representations: ESRL/PSD GEFS: EPS: Precipitation Analogs & CPC Outlook Taking a look at the data below, one could see that some sort of storminess should be impacting the region as the precipitation analogs and CPC outlook suggest moisture availability in the region. Deterministic Precipitation GEFS Raw Ensemble Mean CPC 8-14 day Precipitation Outlook Interesting EPS Control MSLP runs: There have been many different runs over the last few days that hint at the possibility of a storm around this time frame, give or take a day or two. Please, we can see some of the most interesting ones. 12Z Nov 23, 2018 00Z Nov 24, 2018 12z Nov 24, 2018 12Z Nov 24, 2018 12Z Nov 25, 2018 As we know, nothing is etched in stone when it comes to the weather and the atmosphere. However, that is exactly what drives us to keep the faith that nice storms will come and go to satisfy our needs for excitement, snow and rain to replenish the reservoirs and simply to allow us to continue enjoying our favorite hobby or even profession. So, let the DISCO begin, and who knows we may be able to answer the question; Wintry Weather Returns? Have fun tracking and learning!
Phased Vort posted a topic in North East | Mid AtlanticHello, posters and lurkers! It seems that we could get another storm for the east coast before November 2018 is out. Overall main players are the continued active southern stream branch, GOMEX, and SW Atlantic moisture, possible northern stream branch involvement, and the usual presence or lack of High-pressure system over SE Canada acting as the source of cold air, and even possibly blocking the conditions. Basic setup - the low-pressure system should start to develop and gather moisture over the GOMEX and then track over eastern parts of the SE CONUS or track over Florida and then NE or ENE towards the higher latitudes to eastern Maine or southeast Canada. Details such as high-pressure location, northern stream interaction and depth of cold air or lack thereof, will need to be ironed out little by little as this time frame draws near. Please see below an image illustrating the basic setup for this possible storm. Now, onwards to the support data; EPS Control MSLP, BSR and GFS, GEFS, ECMWF and EPS teleconnections (AO, NAO, PNA and EPO) Model Guidance 12Z EPS Control MSLP - 11/12/18 00Z EPS Control MSLP - 11/13/18 Bearing Sea Rule 11/23/18 12Z through 11/27/18 00Z : Teleconnections: GFS AO, NAO, EPO, and PNA, respectively: GEFS - AO and NAO; only these were available at the time of this post creation) ECMWF Teleconection info: (Data from weathermodels.com) AO - ~ -3.3 trending positive NAO - ~ -2.9 stable EPO - ~ +1.3 trending negative PNA - ~ -0.5 slow trend positive EPS Teleconection info: (Data from weathermodels.com) AO - ~ -2.7 stable NAO - ~ -1.4 stable EPO - ~ -0.2 slow trend negative PNA - ~ +1.5 slow trend positive All in all, given the EPS control signal, BSR support for a nearby storm and most of the teleconnections in a favorable status, it seems that the odds for an east coast storm are decent, be it over land east of the Appalachians or just offshore. We will see how all this will evolve, and when the time comes, if there will actually be a storm and where it will track. Have fun discussion!
Hello posters and lurkers; Recently, the Mid Atlantic and Northeast CONUS regions have been influenced by a rather stormy pattern, with consective FROPAs passing through the region and still progged to pass through. These FROPAs bring along with them trofs to the region as the cold fronts depart, and these same trofs can allow for storms to form and affect the region, either as coastal storms, coastal huggers, inland runners, etc. Each trof that swings by the region, therefore, helps to cool down the atmosphere and the surface with the cooler and colder air that accompany them. and as a direct result, progressively increase the snow fall cover over SE Canada and nothern areas of upstate NY and New England, especially over the higher terrain. This evolution of the colder cycle of the northern hemisphere in this almost middle aged fall season, continues to deepen as each day goes by and winter grows nearer. Having this in mind, the time frame for this thread, looks like it could bring a storm, some kind of a storm, that may actually leave its mark on the autumn. Given the interpretation of what the ECMWF deterministic and EPS forecst teleconnections show, along with some foggy BSR support and EPS Emsemble Control MSLP output, one could argue for 2 possible storm scenarios for this time frame; cyclogenesis occuring near the US east coast from a piece of energy just offshore from the southeast coast, as the developing storm tracks N and/or NNE rouding the western periphery of the northern Atlantic ocean ridge OR a bowling ball type storm whose energy would come from the Pacific ocean entering the western US at a certain latitude and exiting the eastern US towards the Atlantic ocean at a more or less similar latitude. This second scenario, could end up being morphed into a clipper like system entering the US from the SW Canada region; Therefore, in other words, one scenario could lead to a more amplified storm and track, with some degree of blocking, whereas the other scenario, could allow for a progressive flow over the CONUS resulting in a less amplified storm track. In both cases, either GOMEX or Atlantic ocean moisture may aid in juicing up the storm. As the days go by, eventualy, we will favor one over the other as the noise and fog clears. Below, one can see the two possible scenarios outlined for this thread´s time frame. Scenario 1: Scenario 2: Teleconnections arguing for either scenario 1 or 2: ECMWF Deterministic: AO; suggesting possible availability of cold air. EPS telleconnections: AO suggesting availability of cold air. EPO suggesting pacific air presence; perhaps arguing for scenario 2. BSR support - shy and foggy: 500mb: Somewhat amplified. BSR surface, somewhat amplified, still possibly conveying a more progresive track.May be arguing for scenario 2. EPS Control Ensemble Control MSLP: This specific outcome argues for scenario 1. All in all looks pretty interesting and at least, a fun attempt at finding a storm to track that could yet make itself apparent on models in a more convincing fashion. So, pick your scenario and discuss.