Severe Weather for Southeast, fires continue

Severe Weather will come with rain as drought conditions are still going strong despite the recent rains.  It cannot be emphasized enough that the fires that saw 3 lives end in Tennessee can still continue over the coming days.    Arson investigations have been opened in some of these fires as investigators begin to determine how the fires started but fire conditions will not take long to return to areas once the rains pass so please remain vigilant in your daily activities when fire is involved.  To all of our readers and their neighbors in these regions,  stay safe and plan ahead.   As seen in Gaitlinburg, these fires can come very quickly.  Prepare in advance and be ready to leave at a moments notice with multiple escape routes as options.

drought-monitor

Rain will continue in the southeast tonight into Wednesday from Extreme Eastern Texas over the South Florida along the gulf up north through Arkansas into the Ohio Valley and Great Lakes regions.  Additional precipitation is possible in New England with freezing rain advisories issued for the higher and more northern elevations.  Severe Weather, including Flash Floods and Tornadoes are possible tonight and will be addressed in this post.

A slowly weakening low pressure system across the northern plains and Upper Midwest will continue to bring potentially heavy snow to the Dakotas into this evening, before snow begins to gradually taper off overnight. Scattered snow and some rain showers will still be possible across the northern plains and Upper Midwest into Wednesday.

Farther east, widespread rain and even some thunderstorms are expected tonight and Wednesday from the lower Mississippi valley to the Northeast. Some areas of heavy rain are possible across portions of the lower Mississippi and Tennessee valleys through tonight as some significant rains have already fallen in the area.

nws_precip_se_1

The showers and thunderstorms will reach the East Coast on Wednesday, with thunderstorms possible from the Southeast to the southern Mid-Atlantic region. By late in the day, snow is expected to develop across northern Maine as the precipitation spreads into colder air already in place. Snow may be heavy
at times Wednesday night into Thursday.

noaad1

Strong low pressure seen here moving into Canada has dragged a cold front south draped down into the Carolinas.  This weakening front brought the region last nights rain.  A second cold front associated with this low is now moving through Illinois down into Texas.  This front, along with a developing warm front moving north from the gulf are what will set the stage for tonight’s Severe Weather risk

Severe Weather Returns

severe weather

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 13,427 585,227 Tupelo, MS…Starkville, MS…Greenwood, MS…Grenada, MS…Oxford, MS…
ENHANCED 42,707 2,601,397 Baton Rouge, LA…Jackson, MS…Monroe, LA…Greenville, MS…Florence, AL…
SLIGHT 113,393 11,559,771 Nashville, TN…New Orleans, LA…Birmingham, AL…Mobile, AL…Huntsville, AL…
MARGINAL 49,543 6,567,755 Memphis, TN…Lexington-Fayette, KY…Montgomery, AL…Knoxville, TN…Beaumont, TX…

The storm prediction center has upgraded a small region in Northern Mississippi to a moderate risk while large portions of the south east remain in an enhanced or slight risk area.  The  risk for Tornadoes is large tonight and Tornado watches have already been issued for several counties.

severe-watch

Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 56,076 3,179,960 Baton Rouge, LA…Jackson, MS…Monroe, LA…Greenville, MS…Tupelo, MS…
15 % 13,456 588,577 Tupelo, MS…Starkville, MS…Greenwood, MS…Grenada, MS…Oxford, MS…
10 % 42,678 2,598,047 Baton Rouge, LA…Jackson, MS…Monroe, LA…Greenville, MS…Florence, AL…
5 % 70,735 7,846,202 Nashville, TN…New Orleans, LA…Birmingham, AL…Huntsville, AL…Metairie, LA…
2 % 43,513 4,379,865 Chattanooga, TN…Clarksville, TN…Beaumont, TX…Gulfport, MS…Lake Charles, LA…

The risk for significant tornadoes exists from Baton Rouge and Monroe Louisiana north towards Florence Alabama and just south of Nashville Tennessee, however, tornadoes can be expected from Beaumont Texas right up into Central Kentucky.

Current Tornado Watches

tor-watch-1 tor-watch-2

These watches extend from near Alexandria Louisiana to almost Jackson Tennessee and include Monroe Louisiana and Jackson and Tupelo Mississippi.  Memphis Tennessee remains just north east of the watch area but Tornadoes can occur outside the watch boxes so vigilance must be maintained.

The latest radar imagery show several strong and locally severe storms ongoing across the Lower Mississippi Valley area.  Advection will continue to occur across the Central Gulf Coast States and move into the Tennessee Valley as an upper level system approaches.  The Severe Weather and Tornado risk will spread northward with time.

firsthand Weather expects that Tornado Watches will continue to be expanded northeastward into further into Tennessee as scattered supercells in Mississippi move in that direction this evening.  Northeast Alabama and Tennessee should begin to see the impacts of these storms this evening into the overnight.  The environment is becoming more favorable for rotating storms as the evening goes on, especially in Northeast Mississippi.  Large hail and damaging winds will also be a risk tonight.

 

 

Robert Millette

Firsthand Weather

 

 

6.9 Magnitude Japan Earthquake – Details

According to USGS,  a 6.9 magnitude earthquake struck off the coast of Japan near Honshu, Japan at 5:59 local time. Tsunami warnings have been issued for coastal regions, and it is being reported that this earthquake was felt across a large region of Japan, including in Tokyo. There is currently little information on the potential damage across the region, and it is being reported that evacuations are taking place near Fukushima.

The figure below includes the location of the earthquake, along with the regions across Japan that felt this earthquake.

Japan earthquake

 

Volatile Pattern Will Drive Swings In Temperatures Across U.S.

Over the last several weeks, unusually warm weather has gripped the United States. In fact, a large region of the United States had temperatures run 4 to 6 degrees above average for the month of October with quite a few regions making it in the 6 to 8 range. There were even some areas that had temperatures over 8 degrees above average for the month. Now, that’s hot!

Many have been wondering for quite some time if the current pattern that has caused such warmth over the United States will eventually break and if this change will occur before we reach the winter months. In short, the answer is yes; however, November will act as a transition month to a colder and more active pattern this winter for the central and eventually the eastern U.S. Firsthand Weather’s winter forecast has not changed since early August, so please read give it a read if you’re wanting a broad overview of what to expect this winter. We have more details that will be released on the site in the coming weeks.

In this article, I want to primarily focus on this month and give a timeline on how our pattern will evolve with time. In order to do this, it’s important to understand what has caused such warm temperatures over the United States. An unusually strong Pacific jet stream has extended across the entire northern Pacific, often reaching the West Coast of the United States (Figure 1). This alone has transported warm, Pacific air into the U.S. Although the flow of this jet has been mostly zonal (west to east flow), the jet has often curved cyclonically in the Gulf of Alaska. A strong mid-level trough has persisted near the Gulf of Alaska, and downstream of this trough, strong ridging has been present (Figure 2). The region under the influence of this ridging has been much of the U.S.

Strong Pacific Jet Stream

Figure 1: A strong west-to-east component of the jet stream was present through much of October.

Gulf of Alaska trough

Figure 2: A persistent trough has been present near the Gulf of Alaska along with quasi-stationary ridging over much of the U.S.

Because of the extension and strength of the Pacific jet stream, storm systems have been able to readily ride the westerlies straight to the West Coast. This is another process that has led to the persistence of ridging over the U.S. With such a setup, given the strength of the Pacific jet and strong Gulf of Alaska trough, large amounts of latent heat have helped strengthen the downstream ridge, thanks to the low pressure systems making it to the West Coast and releasing this latent heat into the ridge. Taking all of this into account, it’s no surprise that stubborn record-warmth has been quite persistent. Just when one ridge weakens, another just builds right behind it.

What To Expect Through Thanksgiving (Broad Overview):

The big question becomes. . .how long will this pattern persist? First, let’s address what needs to happen for a pattern change to occur. The anomalously lower heights (the trough over the Gulf of Alaska) needs to weaken and retrograde west some. In addition to that, the Pacific jet stream needs to calm down quite considerably. It needs to have more of a meridional (north to south) component to it, which would open the door for more ridging to build along the West Coast and extend into Alaska. This, in effect, would allow Arctic air to spill into the United States east of the Rockies, as troughing would be more present over those regions.

My argument over the last week or two hasn’t been that the pattern isn’t going to change into something more seasonable, but that there is going to be a transition period before the more “permanent” change. In other words, there’s going to be quite a bit of volatility to the pattern with swings in temperature, so if you’re looking to get persistent cold in the central or eastern United States, I don’t expect that to occur until later November closer to Thanksgiving or even later. However, the colder intrusions that push into the U.S. before Thanksgiving will be a huge shock to the system, and some could even be potent. Even once we get past Thanksgiving, I’m not ruling out potentially another warmup, especially across the Southeast and parts of the East Coast. Again, all of that is discussed in the Firsthand Weather winter forecast.

What Will Transpire This Week (Broad Overview):

Volatility in the pattern is not a bad thing if you’re looking for some real action. Behind a ridge that is currently moving from west to east across Canada and the U.S., another ridge is going to build over the same regions early to mid week (Figure 3). This will cause temperatures to soar by mid-week across the western third of the U.S. into the Northern Plains. However, a wave that will move across southern Canada and the Upper Midwest ahead of this ridge will pave the way for a front to move through the Plains and eventually eastward. This won’t be an Arctic front by any means, but it will help to alleviate the really hot temperatures across the Southern Plains and some regions east of that.

U.S. Ridge 1

Figure 3: Another ridge will build into the U.S. and Canada midweek.

The building midweek ridge will eventually break later in the week (imagine a wave in the ocean building and crashing), which will shove a disturbance into the Southeast. It may help cool temperatures down slightly, but this won’t be a rain-maker. I don’t expect any significant rain chances across the Southeast until at least mid-November. I’ll have a separate post on that soon.

Yet another ridge will build over parts of the U.S. and Canada late in the week and will also break (Figure 4). Downstream of the ridge, this will push much cooler temperatures into the Great Lakes region, the Northeast, and parts of the Mid-Atlantic. This cooler air will spill down into the Tennessee Valley and parts of the Southeast (Figure 5). The air mass will be much more potent farther north, but this will seem like a big improvement even farther south, given how hot it has been. The lake effect snow machine will start to crank up this week, and I expect the lake-effect snow to be a big deal (above average) late fall and early this winter.

U.S. Ridge 2

Figure 4: Yet ANOTHER ridge will build into the U.S. and Canada late week.

Temperature Anomaly Map

Figure 5: A downstream trough will develop, allowing for much cooler weather over the Northeast, Great Lakes, Mid-Atlantic, and even southward next weekend.

This will be followed by more warmth, and this cycle will pretty much continue through Thanksgiving. Forecast models do indicate that ridging will begin to build over the West Coast after mid-month, which could open the door for additional and potentially colder air masses to drop southward into the central and eastern U.S. after that point. In fact, some models have a stronger low pressure system developing in the Gulf of Mexico mid-month, which could bring relief to the drought-stricken Southeast and help usher in colder, more seasonable air across the central and eastern U.S.

Conclusion:

I realize that I jumped around quite a bit in this article, but the goal was to show everyone the volatility of the evolving pattern. Forecast models often don’t handle pattern transitions well, so keep that in mind if you rely on weather apps or weather forecasts that are based heavily on model data.

Also keep in mind that with the kind of warmth that will be building over Canada over the next week or two, this will not allow much snow cover to advance over that region. This could act to modify some of the cooler air masses that drive southward into the U.S. and keep them a bit milder than they otherwise would be.

Despite the back and forth in temperatures that many of you will experience through Thanksgiving, this should excite many of you fall/winter lovers out there. I will continue to keep you updated as the pattern evolves with time, and let you know how this will impact your weather.