...Heavy snow for the Cascades, Sierra and Northern Rockies... ...There are moderate flash flooding and severe weather threats over portions of the Lower Mississippi & Tennessee Valleys and Southeast tonight...
...Heavy snow in parts of southeastern New Mexico and West Texas through tonight... ...Heavy rainfall and flash flooding will continue along the Texas Gulf Coast through tonight... ...Heavy mountain snow possible in the Pacific Northwest and northern Rocky mountains this weekend...
...Rain and mountain snow possible across the Northern/Central Rockies and Northern Plains today... ...Heavy rainfall to spread across parts of the Southern Plains and Lower Mississippi Valley on Thanksgiving Day... ...Potentially impactful snow could begin as early as Thursday night for parts of the Southern Plains...
During the week, we provide 48-Hour reports which focus on the shorter-term predictions but also have links to all the partial-month outlooks.
Once a week we show many of the actual forecast maps not just provide the links to these maps. This makes it easier for the reader. Our report provides a separate forecast for Days 1 and 2, Days 1-5, Days 6 -10, Days 8 – 14, and weeks 3 and 4. We also include a next-day and 10-Day World Temperature and Precipitation Forecast. This provides information that is useful to readers in terms of planning their activities for the weekend and the next 28 days. Tomorrow and Monday I will update the article with more recent short-term forecasts.
From the Week 3 -4 Discussion:
Over the equatorial Pacific, La Niña conditions persist, with below normal sea surface temperatures (SSTs) and reduced tropical convection in all Niño regions. In contrast, convection currently exists over the Maritime Continent associated with the emergence of the MJO into RMM phase 5. Both GEFS and ECMWF ensemble forecasts depict the propagation of the MJO through phases 5, 6 and 7 (Maritime Continent to the Western Pacific) over the next two weeks. After this time, the ensemble spread indicates a great deal of uncertainty as to either the continued propagation or the decay of the MJO. Regardless, the tropical convection associated with this active MJO during the two weeks leading up to Week 3-4 will produce upper-level divergence that resides in a favorable location to interact with the subtropical jet exiting southeast Asia. This interaction will produce a source for Rossby waves capable of propagating downstream and impacting surface conditions over CONUS/AK during the Week 3-4 period. Statistically, this sort of propagation is associated with troughing over AK and ridging over CONUS at short leads. However, at Week 3-4 leads the pattern typically reverses with ridging over AK and trouging over CONUS, reminiscent of a negative PNA pattern. Further downstream, a negative NAO is typically observed. Thus, a pattern shift that projects onto the negative phases of both the PNA and NAO is favored to occur near the end of Week 2 or beginning of Week 3. Whether this shift actually occurs and its exact timing are uncertain, which leads to overall low confidence probabilities throughout this Week 3-4 forecast.
I have chosen not to try to explain all the factors that go into this forecast. If anyone is interested post a comment and I will reply to it.
When we publish on Friday night, it provides a 28-day view of the future. What is important is that this is a longer-term view than one that is typically available in the media and online.
...Heavy lake effect snow downwind of the Great Lakes... ...Anomalous cold for South and East; Elevated fire risk for Southern California...
...Heavy lake effect snow downwind from the Great Lakes... ...Temperatures will be 10 to 25 degrees below average from the Great Lakes to the Rockies... ...There are Winter Storm Warnings, Winter Weather Advisories, and Lake Effect Snow Warnings snow downwind from the Great Lakes through the end of the forecast period...
...Wintry precipitation will continue in northern New England through this evening as a coastal low tracks northeast... ...Major lake effect snow event downwind of the Great Lakes likely to begin tonight and continue through the weekend... ...Anomalous cold will continue for most of the CONUS through the end of the week... ...Strong Santa Ana winds across southern California will relax tonight...
...Mixed precipitation expected for inland areas in the Northeast and Mid-Atlantic this afternoon into Wednesday morning... ...Heavy Lake Effect Snow in the Great Lakes region Wednesday and Thursday, especially downwind of Lake Erie and Lake Ontario... ...Strong Santa Ana winds return today across Southern California... ...Anomalous cold will continue for most of the CONUS through the end of the week...
...Light snow accumulations across the mid-Missouri Valley and Midwest through Tuesday morning... ...Coastal rain; inland mixed precipitation on Tuesday evening into Wednesday across Northeast and Mid-Atlantic as coastal low develops and moves up coast... ...Anomalously cold air will continue to grip the lower 48 through the work week... ...Strong Santa Ana winds return across Southern California on Tuesday; High Wind Warnings in effect...
...Lake-effect snow downwind from the Great Lakes Sunday night into Monday... ...Light snow from the Southern High Plains to the Upper Midwest Monday evening into Tuesday... ...There are Winter Weather Advisories across parts of the Central Plains for Monday...
