January 2019 - Active Progressive WX Pattern Ahead
FV3 looks like a close call with temps in the low to mid 30's as the precip ends fwiw
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CRASHWX
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In almost every situation such as this....what have we seen with temps? Answer...models don’t handle shallow air so if it’s calling for a close call now by 2-4 degrees...I’m gonna bet on the past that temps are undercooked!
CRASHWX As far as I can remember with winter weather events here in southeast TX, all of them were never forecasted this far out on the models. They weren’t picked up till one or two days before it actually happened.
I am in S. Louisiana west of New Orleans. I follow this forum because many times what you folks get in SE Texas, we get the next day.
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MontgomeryCoWx
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My hometown of Longview would pick up 4-6 inches. That doesn’t seem too far fetched. The L will usually get one storm a winter where they get 3+ inches of snow.
I fly back that day from Florida. That would be nice
Team #NeverSummer
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srainhoutx
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Interesting discussion for the Climate Prediction Center yesterday afternoon in their Week 3 and 4 Outlook. The MJO is a big driver in the forecasting challenge as well as the volatility of the Sudden Stratospheric Warming Event.
Prognostic Discussion for Week 3-4 Temperature and Experimental Precipitation Outlooks
NWS Climate Prediction Center College Park MD
300PM EST Fri Dec 28 2018
Week 3-4 Forecast Discussion Valid Sat Jan 12 2019-Fri Jan 25 2019
The present Weeks 3 and 4 outlook is issued amidst a number of interesting climatic phenomena that may play substantial roles in the evolving circulation across North America. First, the low frequency state with above-normal sea surface temperature (SST) anomalies in the Pacific continues to persist, with some recent cooling east of the Maritime Continent potentially helping to increase the meridional gradient in these values, which could increase odds for a canonical El Nino teleconnection. The subseasonal tropical state appears likely to constructively interfere with the low frequency state in the Pacific, with the Madden-Julian Oscillation (MJO) forecast to cross the Maritime Continent in the near future. The resultant circulation outlooks feature a positive Pacific-North American (PNA) pattern coupled with a high amplitude wave train over much of the Western Hemisphere. The MJO crossing into the Pacific also has demonstrated implications for helping to drive the Arctic Oscillation (AO) into a negative state due to poleward and vertically propagating Rossby waves emanating from the MJO envelope, with some models (ECMWF, JMA) suggesting this mechanism being in play. Lastly, a stratospheric warming event is forecast to occur in approximately the next week, but questions persist whether this event will be sufficient to propagate downward to the surface. Confidence is highest in the tropical influences on the forecast (i.e. El Nino, MJO, and resulting AO response), with possible stratospheric influences minimized in the resulting outlook, although the purported stratospheric response would superimpose some on the MJO-AO interplay. The ECMWF and JMA models appear to have a decent handle on the interplay of low frequency and subseasonal footprints, in addition to the anticipated AO response, while statistical guidance based on canonical teleconnection impacts of El Nino and the MJO in addition to decadal trends are also leveraged in the final outlook.
In addition to the PNA pattern noted across the Pacific, and to some extent North America, model guidance varies most substantially east of the Mississippi. The CFS model is an outlier with an elongated anomalous 500-hPa ridge stretching along the entirety of the northern U.S. just to the south of the Canadian border. The ECMWF and JMA feature more ridging closer to the pole, and a negative AO with corresponding anomalous troughing over the eastern U.S. and portions of northern Eurasia. Anomalous troughing in the CFS is confined far south (below about 30N) across parts of Texas and the Gulf states. All models feature some degree of anomalous ridging across eastern Alaska, with the CFS the least pronounced among the guidance.
The temperature outlook features an east-west dipole of below- and above-normal temperatures in response to the forecast anomalous ridging over the West and troughing over the East. Highest confidence for above-normal temperatures across the CONUS is over parts of the Pacific Northwest coincident with the anomalous ridge axis and typical PNA loading pattern, while the lagged response to a Phase 5 MJO also supports a warmer than normal solution here. The MJO would also support anomalous cold focused from the Northern Plains through Northeast, although the typical El Nino response would dampen this signal across the Northern Plains and Great Lakes. Instead, the highest probabilities for below-normal temperatures are focused over the eastern U.S., where anomalous troughing is anticipated linked to the potential negative AO state. Boosted chances for above-normal temperatures are also featured across the entirety of Alaska, with highest confidence across northern and eastern portions of the state, tied to the forecast anomalous ridging, that also projects somewhat onto the MJO response in addition to decadal trends.
The precipitation forecast trends drier than normal for most regions, tied to the anticipated ridge-trough pattern helping to keep the Pacific jet away from the West coast, while the trough over the east imports continental polar airmasses that are relatively dry. One exception is above-normal precipitation being favored from the Central Gulf coast through Mid-Atlantic, with a mean frontal zone possible here and increased storm activity possible along the baroclinic zone setting up along the eastern seaboard. While not directly implicated, this circulation could increase odds for a substantial winter storm across the major metropolitan areas in the East. Equal chances are forecast for portions of the Northern and Central Rockies and Plains, where uncertainty regarding the potential for upslope precipitation or shortwave activity diving into the anomalous trough muddies the outlook. Model guidance is similarly mixed across California, leading to equal chances being forecast here. Below-normal precipitation odds are also increased across Alaska, with the exception of the Aleutians, with the anomalous ridge axis forecast to be across eastern portions of the state.
Sea surface temperatures in the vicinity of Hawaii remain above normal, and the bulk of dynamical model guidance depict enhanced chances for above-normal temperatures, especially over the southeastern islands. Dynamical model precipitation forecasts generally favor below-median rainfall over the Hawaiian Islands, consistent with the low-frequency state over the tropical Pacific during boreal winter.
NWS Climate Prediction Center College Park MD
300PM EST Fri Dec 28 2018
Week 3-4 Forecast Discussion Valid Sat Jan 12 2019-Fri Jan 25 2019
The present Weeks 3 and 4 outlook is issued amidst a number of interesting climatic phenomena that may play substantial roles in the evolving circulation across North America. First, the low frequency state with above-normal sea surface temperature (SST) anomalies in the Pacific continues to persist, with some recent cooling east of the Maritime Continent potentially helping to increase the meridional gradient in these values, which could increase odds for a canonical El Nino teleconnection. The subseasonal tropical state appears likely to constructively interfere with the low frequency state in the Pacific, with the Madden-Julian Oscillation (MJO) forecast to cross the Maritime Continent in the near future. The resultant circulation outlooks feature a positive Pacific-North American (PNA) pattern coupled with a high amplitude wave train over much of the Western Hemisphere. The MJO crossing into the Pacific also has demonstrated implications for helping to drive the Arctic Oscillation (AO) into a negative state due to poleward and vertically propagating Rossby waves emanating from the MJO envelope, with some models (ECMWF, JMA) suggesting this mechanism being in play. Lastly, a stratospheric warming event is forecast to occur in approximately the next week, but questions persist whether this event will be sufficient to propagate downward to the surface. Confidence is highest in the tropical influences on the forecast (i.e. El Nino, MJO, and resulting AO response), with possible stratospheric influences minimized in the resulting outlook, although the purported stratospheric response would superimpose some on the MJO-AO interplay. The ECMWF and JMA models appear to have a decent handle on the interplay of low frequency and subseasonal footprints, in addition to the anticipated AO response, while statistical guidance based on canonical teleconnection impacts of El Nino and the MJO in addition to decadal trends are also leveraged in the final outlook.
In addition to the PNA pattern noted across the Pacific, and to some extent North America, model guidance varies most substantially east of the Mississippi. The CFS model is an outlier with an elongated anomalous 500-hPa ridge stretching along the entirety of the northern U.S. just to the south of the Canadian border. The ECMWF and JMA feature more ridging closer to the pole, and a negative AO with corresponding anomalous troughing over the eastern U.S. and portions of northern Eurasia. Anomalous troughing in the CFS is confined far south (below about 30N) across parts of Texas and the Gulf states. All models feature some degree of anomalous ridging across eastern Alaska, with the CFS the least pronounced among the guidance.
The temperature outlook features an east-west dipole of below- and above-normal temperatures in response to the forecast anomalous ridging over the West and troughing over the East. Highest confidence for above-normal temperatures across the CONUS is over parts of the Pacific Northwest coincident with the anomalous ridge axis and typical PNA loading pattern, while the lagged response to a Phase 5 MJO also supports a warmer than normal solution here. The MJO would also support anomalous cold focused from the Northern Plains through Northeast, although the typical El Nino response would dampen this signal across the Northern Plains and Great Lakes. Instead, the highest probabilities for below-normal temperatures are focused over the eastern U.S., where anomalous troughing is anticipated linked to the potential negative AO state. Boosted chances for above-normal temperatures are also featured across the entirety of Alaska, with highest confidence across northern and eastern portions of the state, tied to the forecast anomalous ridging, that also projects somewhat onto the MJO response in addition to decadal trends.
The precipitation forecast trends drier than normal for most regions, tied to the anticipated ridge-trough pattern helping to keep the Pacific jet away from the West coast, while the trough over the east imports continental polar airmasses that are relatively dry. One exception is above-normal precipitation being favored from the Central Gulf coast through Mid-Atlantic, with a mean frontal zone possible here and increased storm activity possible along the baroclinic zone setting up along the eastern seaboard. While not directly implicated, this circulation could increase odds for a substantial winter storm across the major metropolitan areas in the East. Equal chances are forecast for portions of the Northern and Central Rockies and Plains, where uncertainty regarding the potential for upslope precipitation or shortwave activity diving into the anomalous trough muddies the outlook. Model guidance is similarly mixed across California, leading to equal chances being forecast here. Below-normal precipitation odds are also increased across Alaska, with the exception of the Aleutians, with the anomalous ridge axis forecast to be across eastern portions of the state.
Sea surface temperatures in the vicinity of Hawaii remain above normal, and the bulk of dynamical model guidance depict enhanced chances for above-normal temperatures, especially over the southeastern islands. Dynamical model precipitation forecasts generally favor below-median rainfall over the Hawaiian Islands, consistent with the low-frequency state over the tropical Pacific during boreal winter.
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Twitter @WeatherInfinity
we will be in Lake Travis Jan 3-6 so I hope we get to see something but it looks like any event may be over by the time we get there.
Trying to interpret the above. So, the SSW event has yet to take place and the impacts really won't be known until it does and whether it reaches the surface. Also, a positive PNA and -AO would mean a colder eastern half of the country and warmer in the west. The influences of the SSW event could be compounded on top of this. Am I close?
The SSW event is occurring right now, but you won’t notice it for at least a couple more weeks. Also, that doesn’t mean it will impact our side of the globe. It could be a big event for Europe or someone else. A SSW event doesn’t always guarantee cold for the U.S. We won’t really know till mid January. Yes, a +PNA basically means you get a trough over the east and a ridge over the west. Basically that means a dry west and a wet east, but if you combine that with a -AO then that’s when you can start talking about some cold air towards the east along with an active storm track because of where the trough is situated. Cold air bleeds down into the base of troughs. Now if you combine a -EPO into the mix along with a -AO then you can really start talking about some big time cold making its way down south. Then also, there’s this thing calle the MJO that consists of 8 different phases. Right now, I believe it’s in phase 5 going into phase 6. What we need for it is to go into phase 8 and phase 1 because those two are notoriously known for producing cold into the U.S. I also want to add that you don’t want the PNA to go too far into the positive phase because that could push the trough too far east for us to get any cold or active weather. What would be ideal for cold and snow would be a neutral PNA, -AO, -EPO, and for the MJO to go into phases 8 & 1. That’s a dream scenario.harp wrote: ↑Sat Dec 29, 2018 9:37 am Trying to interpret the above. So, the SSW event has yet to take place and the impacts really won't be known until it does and whether it reaches the surface. Also, a positive PNA and -AO would mean a colder eastern half of the country and warmer in the west. The influences of the SSW event could be compounded on top of this. Am I close?
So, we are back to hurry up and wait! LOL! 
The trends are nice on the models. 12z GFS trended even more in our favor. The GFS shows temps in the mid to upper 30’s across SETX while the precip is going on. The GFS has a warm bias though and is usually a good 5+ degrees too warm. Thursday is looking wet now too on the GFS.
Last edited by Cpv17 on Sat Dec 29, 2018 10:28 am, edited 1 time in total.
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Kingwood36
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Can’t you get frozen precip without that 540 line with wet bulb?
If dew points are low enough.
Sleet/snowfall map on new GFS looks encouraging for you guys.
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Kingwood36
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Not sure how. I'm sure someone will.
The end of the 12z FV3 looks very nice!!! Best look I’ve seen on any model this whole winter. Only problem is that it’s in fantasy land, but it would point towards the middle of the month for a January cool down that so many people have been talking about.
I'm looking at it. Can you explain what you mean?