Friday, September 30, 2016

4 things to know about the weather for the first week of October

We're moving out of a very dry (and hot until this past week) September into October, which typically means fall begins in earnest. Average highs drop from 80° to 70° over the course of the month, record highs drop into the 80s, and morning lows in the 40s become more likely, especially the latter half of October. With a taste of dry air and fall weather this past week, what does the first week of October bring? Here are 4 things you need to know:

1. A gorgeous weekend is ahead! Highs will generally be near 80° or so with lows near 60° in the city and back into the 50s outside the loop. Clouds will stick around, especially during the daylight hours this afternoon and tomorrow, but more sun will be expected on "Sun"-day. Humidity levels remain comfortable as dewpoints stay in the 50s. Open the windows in the evenings and pop that sunroof! There are also plenty of outdoor activities that you can take advantage of.

2. The cool temperatures of the past few days will give way to warmer air next week. Fortunately, we're not talking about a string of 90s, but mid to upper 80s for the middle of next week will be warm enough as humidity creeps back up just a a bit as well. Dry weather continues.

High temperatures for Wednesday, October 5, according to the American GFS model. (WxBell)

3. A cold front will move through mid-to-late next week (likely Thursday), which will bring our next chance of rain and possibly a few thunderstorms. It looks to be a quick hitter though, so no prolonged rainfall is expected to help with our recent deficit. Behind it, slightly cooler and drier air again works its way into the Mid-South.

The surface forecast for next Thursday morning from the NWS shows a cold front moving toward the Mid-South, which will provide our next chance of rain. (NOAA/NWS/WPC)

4. And as a bonus, outside the Mid-South, eyes are on Major Hurricane Matthew which is churning it's way through the southern Caribbean Sea. It's moving west off the coast of South America (yes, that is pretty far south for a Caribbean storm), but will make a hard right turn and head north towards Jamaica and Cuba early next week then into the Bahamas by the middle of next week.

Latest forecast track for Hurricane Matthew from the National Hurricane Center
Significant impacts are possible in all of those locations as no noticeable weakening is expected until it interacts with the island of Cuba. It remains to be seen how much effect Cuba has on it. After the Bahamas, the east coast of the U.S. needs to keep a close eye on Matthew's track. Some models take it towards the Outer Banks of North Carolina, then turn it east, but it is still a long ways out from that. More detail can be found on the MWN Tropical Page.

Based on the output of many meteorological computer models, the potential paths of Matthew are shown above. These "spaghetti plots" change routinely and are not all possible options.
Enjoy the fall weekend!

Erik Proseus
MWN Meteorologist

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Friday, September 23, 2016

Another hot weekend, then FALL arrives!

Tired of the heat? Yeah, me too.  If you can hold out another couple days, I have great news!

Despite fall officially starting on Thursday morning (you didn't try balancing an egg on end at 9:21am did you?), summer weather continues for a few more days. Thursday's high of 95° came within a degree of the record and we'll threaten the record high of 96° again today, as well as the 95° records both Saturday and Sunday. High pressure ridging aloft more typical of mid-summer is to blame. I'm over it...

Mid-afternoon temperatures on Friday are well above normal for many areas east of the Rockies under the dominance of high pressure aloft. (
But by Monday, we'll start to see the major pattern shift as a massive upper-level trough over the western U.S. this weekend, upstream from our large ridge of high pressure, begins shifting east. It'll flatten out some as the main low pressure area goes by well to our north. However, it will be enough to push a cold front slowly south through the region Monday and Tuesday, resulting in a chance of showers and a "seepage" of more autumn-like air into the Mid-South.

The European model shows the upper level pattern (500 mb/18,000 feet) on Saturday morning dominated by a large trough of low pressure in the west and huge ridge of strong high pressure in the east, centered over the Mid-South. Weather systems moving across the U.S. roughly follow the black line. (

According to the European model (and GFS, not shown), as the low in the image above lifts northeast into southeast Canada by Tuesday morning, the eastern U.S. ridge flattens, allowing cooler air to drop south. Meanwhile, a ridge builds back to the west. As it shifts east later next week, temperatures will warm back up, but likely not to the levels we see this weekend. (
The rain chances with this front, despite there being a fairly large temperature gradient across it, will be fairly low thanks to most of the moisture remaining to our west in the southern plains and the dynamics associated with low pressure heading well to our north. Severe weather is not on the docket. The best rain chances will be Monday into Monday evening (and even then only about 30%). We could use some rain, so the little we might get will likely just set the stage for continued dryness next week as cooler high pressure builds in.

The Short-Range Ensemble Forecast (SREF) model data shows probabilities, including this map of probabilities of 0.10" of rain through Monday afternoon. The best rain chances over the next few days occur to our west. The SREF indicates only about a 30% chance we'll see 0.10" of rain with Monday's front. (WeatherBell)
Behind the front, we'll see temperatures more akin to "normal" for late September - cool mornings in the 50s (especially outside the city) and highs in the upper 70s to near 80. Mid-range model data has some disagreement in the strength of the cool air though. If the American GFS model wins out, outlying areas COULD see some lows in the upper 40s by mid-week. For now, that seem a bit of a stretch.

The GFS Ensemble Forecast System (GEFS) consists of multiple iterations of the American GFS model. Above, the average high and low temperatures from the GEFS members show a very welcome shift from summerlike temperatures to fall early next week. Note that its European counterpart (not shown) is similar but not as cool especially for morning lows, next week. (WeatherBell)
In the long-term, it appears this current streak of 90s may be our last for this year, but above normal temperatures are expected to return by early October.  The good news is that "above normal" for that time of year puts us in the 80s and humidity values are expected to remain tolerable. Here's to the arrival of fall next week!

From NOAA's Climate Prediction Center, there is a high probability that temperatures return to "above average" for the first week in October for most of the country east of the Rockies. (NOAA/CPC)

Erik Proseus
MWN Meteorologist

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Friday, September 16, 2016

Rain for weekend activities? And what about this heat?

I spent a very worthwhile several days in Norfolk, VA this week at the National Weather Association Annual Meeting. The NWA is one of two professional organizations for meteorologists, geared primarily towards operational forecasters. There were lots of great presentations and networking opportunities, but I'm glad to be back! Here's one of my favorite pics - Jim Cantore really is a great guy!

As we get deep into mid-September, it's about time for the heat to depart! This week has been another cooker with highs in the mid to upper 90s. Fortunately, dewpoints have been a bit lower than when we had these same temperatures in the midst of summer, so heat indices have remained below 100 for the most part. As we head into a busy weekend for outdoor events, such as the Cooper Young Festival, a Memphis Tigers football game, and of course Friday night high school football, there are a couple of changes to the past week's pattern - a bit less heat and a bit more rain!

Starting tonight, things are looking good, but warm, for football. Temperatures will settle into the 80s by dusk and rain chances are minimal. Wear your favorite school's t-shirt and leave the umbrellas at home.

By Saturday morning, the ridge of high pressure that has dominated our pattern this week will move east as a large upper-level trough moves closer. That will push a front into the area and rain chances go up. There could even be showers around by dawn tomorrow, but the best chances look to be from mid-morning through early afternoon. Rain chances right now stand at about 50% but a complete washout is not expected.

If you have plans to go to Midtown for either of the two big draws tomorrow, bring your poncho and have a good time, but expect some rain at some point and keep your eyes and ears open for lightning and thunder. Your MWN app will come in handy, even though the NWS Doppler is down. Our radar will continue to show you what's headed your way. Rain amounts will generally be in the 1/2" range with some areas seeing a bit more or less.

The American GFS model showing expected rainfall totals through 7pm Saturday. Heaviest rain, and highest rain chances will be to our north, but scattered showers and a few thunderstorms are also expected locally, mainly in the middle part of the day. (PivotalWeather)
The Storm Prediction Center severe weather outlook for Saturday shows a risk of "general" (non-severe) thunderstorms in the metro. Severe weather is more likely well to our west. (NOAA/NWS/SPC)
As mentioned, thunderstorms are also possible, but severe weather is not anticipated. There's just not going to be enough upper level wind energy or low level instability to generate strong wind or hail. If lightning is nearby, take your lightning safety precautions. Your car is the best place to be if a sturdy structure is not accessible, but indoors is best. They'll put you on the concourses at the Liberty Bowl if lightning threatens, but trust me, that's only marginally safer than the exposed bowl. If you can find a way to get walls around and over you, that's better.

Rain chances go down in the evening as the upper level wave responsible for the daytime activity moves east. Levitt Shell and other evening activities have a better chance of remaining dry than those earlier in the day, but a shower is still possible well into the evening.

Sunday is questionable. Some models dry us out, others hang some atmospheric energy back and keep rain chances in the forecast. With the core of the upper level trough moving overhead, the prudent forecast maintains at least a chance of showers or a thunderstorm, which I have done. Probability of precipitation is 30-40% Sunday, subject to change. If you're picking the drier day this weekend for outdoor stuff, Sunday is your best bet.

The American GFS model at 500mb (18,000') shows the trough moving through Sunday evening that ends rain chances as high pressure builds quickly in behind it, escorting heat back into the Mid-South next week. (PivotalWeather)

Heading into next week, unfortunately a summer-like ridge of high pressure builds over the central U.S. once again and we heat back up. The MWN Forecast is carrying 90's throughout the week with mid 90s quite possible in the middle of the week, and virtually no rain chances.

The mid-level weather pattern for the middle of next week, as shown by the American GFS model, is dominated by anomalously high pressure over much of the CONUS and centered over the Southern Plains. This will lead to hot conditions. (WeatherBell)
The good news is that in the long-term (a week to 10 days out), I'm seeing a fairly strong pattern shift that should bring more autumn-like weather to the region for the end of September. It can't come soon enough!

Erik Proseus
MWN Meteorologist

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August 2016 Climate Data for Memphis, TN

August Recap

Summer continued full bore in August as the hot weather of June and July continued into the month. In fact, August placed in the top 10 hottest on record in Memphis (#10), meaning that all three summer months were ranked in their individual top 10 warmest. At the end of August, a new record was established for consecutive days above 70°, standing at 82 days. The hottest day of the month was 99° on the 5th.

The summer will best be defined by its persistent heat and warm nights, not extreme highs, as the mercury only touched the 100° mark on one occasion. A two-month-long streak of average temperatures above 80° ended in the middle of the month, as well as a 72-day streak of highs at or above 88°. Both of these streaks rank in the top 3 longest on record. The average temperature of 84.3° for June-August was 2.9° above the climate average and ranks as the 4th hottest summer in Memphis' recorded history.

In terms of precipitation, the month started dry, but thunderstorms were abundant during the mid-month period, ending with above average rainfall for the metro by over 2.5". Four days recorded more than 0.75". For the summer season, Memphis ended with 14.72" of rainfall which is 3.62" above the long-term climate average. Only two severe weather warnings were issued for the month in the metro, one over Memphis and the other for eastern DeSoto and northwest Marshall Counties. No severe weather reports were received in the Memphis metropolitan area.

Memphis International Airport, Memphis, TN

Average temperature: 84.6 degrees (2.6 degrees above average)
Average high temperature: 92.5 degrees (1.2 degrees above average)
Average low temperature: 76.7 degrees (4.0 degrees above average)
Warmest temperature: 99 degrees (5th)
Coolest temperature: 70 degrees (22nd)
Records set or tied: Daily record high minimums (warmest low temperatures) were tied on the 2nd (81°), 10th (81°), and 30th (79°).
Comments: 22 days recorded highs at or above 90 degrees in August, which is 2.8 more than average. This month tied for the 6th warmest August on record in Memphis. For the year, the average temperature is 67.0 degrees, which is 2.0 degrees above normal and ties for fourth warmest January-August period on record.

Monthly total: 5.53" (2.65" above average)
Days with measurable precipitation: 10 (3.2 days above normal)
Wettest 24-hour period: 1.82" (20th-21st)
Records set or tied: None
Comments: Three days recorded one inch of rain or more. Through the first seven months of 2016, Memphis International Airport has recorded 49.81" of precipitation, or 14.43" above average (141%). That also ranks as 7th wettest on record for the January-August period.

Peak wind: South/45 mph (25th)
Average wind: 5.7 mph
Average relative humidity: 69%
Average sky cover: 50%

Click here for a daily statistical recap for Memphis International Airport.

Cirrus Weather Solutions /, Bartlett, TN

Average temperature: 81.1 degrees
Average high temperature: 91.3 degrees
Average low temperature: 73.3 degrees
Warmest temperature: 97.9 degrees (4th)
Coolest temperature: 64.9 degrees (22nd)
Comments: None.

Monthly total: 3.30" (automated rain gauge), 3.48" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 11
Wettest date: 1.03" (15th) (via automated gauge)
Comments: None

Peak wind: 15 mph (14th)
Average relative humidity: 84%
Average barometric pressure: 30.00 in. Hg

Click here for a daily statistical recap for Bartlett, TN.

MWN Forecast Accuracy

MWN average temperature error: 1.95 degrees
MWN forecast temperatures within 2 degrees of actual: 67%
MWN average dewpoint error: 1.42 degrees
MWN forecast dewpoints within 2 degrees of actual: 81%

MWN's forecasts extend out five periods (2.5 days, or roughly 60 hours). Historical accuracy statistics can be found here.

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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Friday, September 9, 2016

Another cold front gets us one more step closer to autumn

As we get deeper into September, the resumption of heat and humidity behind cold fronts that now arrive about once a week is slightly more bearable (though low to mid 90s is still too hot for this time of year). A sign of the times as we near fall! As we head into the weekend, another cold front pushes through with a rebound in temperatures behind it, but not quite to the extent of this week's 90s.

This weekend brings that next front, more specifically during the day Saturday. It will be accompanied by scattered showers and thunderstorms, with about a 40% chance of rain most anytime during the day. The additional cloud cover and scattered precip will keep temperatures in the 80s and wind will shift to the north by late afternoon.

The surface map for Saturday morning shows our cold front approaching. I(t will move through in the afternoon accompanied by scattered showers and thunderstorms. (NOAA/NWS)

The effects of the front will be most pleasantly felt on Sunday and Monday with highs remaining in the mid 80s and cooler lows in the 60s, as well as low humidity and a sunny sky. If you have outdoor things to do, Sunday is going to be gorgeous!

Behind the cold front, drier air, as seen by dewpoints in the 50s, will make for a very pleasant Sunday. Plan to get out and enjoy a taste of fall as highs remain in the mid 80s! (

Heading into next week, we'll start to see a slight rebound in those temperatures back to the 90° range or so though humidity won't be oppressive. A couple showers are possible in the afternoon hours, especially mid-late week. Yet another front looks to slowly drop in from the north late next week, bringing a slightly-cooler airmass than the preceding one. As mentioned above, it seems that each front starts to reinforce that fall is coming soon!

I'll be in Norfolk, VA for the National Weather Association Annual Meeting this weekend and the first half of next week. It's a great conference with lots of learning and socializing with other weather geeks, as well as gaining continuing education towards the Digital Seal of Approval displayed below. Thanks as always to #TeamMWN for keeping the home fires burning! Have a great weekend!

Erik Proseus
MWN Meteorologist

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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Friday, September 2, 2016

Four things to know about our Labor Day weekend weather

It's been a long time coming, but we've finally got some beautiful weather in the Mid-South! And not a minute too soon... because it's a holiday weekend! If you have outdoor plans this weekend (and who doesn't there's SO much going on), here are 5 things you need to know about our Labor Day weekend weather.

1. The streak is over!

A couple weeks ago we ended lengthy (two-month-plus) heat streaks - one for daily average temperatures over 80° and another for high temperatures above 88°. This morning, the last summer-long warm weather streak came to an end. Until this morning, we had not had an official low temperature in the 60s since June 10. 83 days later, and after breaking the record on Thursday morning set in the scorching summer of 1980, that streak came to a merciful end as the low dropped to 68° at the airport.

2. Early autumn-like dewpoints

The dewpoint (a direct measurement of the amount of moisture in the air) is related to relative humidity, which tells us how "sticky" the air is, and drives things like low temperatures. It's one of two contributors to the heat index (temperature being the other). We've endured dewpoints well into the 70s most of this summer, which is very muggy, and coupled with temperatures in the 90s produces heat indices well above 100. A cold front that moved through Thursday afternoon has brought a nice northerly breeze and forced dewpoints down into the upper 50s this afternoon and it's like a breath of fresh air! These cool dewpoints will stick around through Saturday before starting to rise again Sunday and Labor Day. That will mean cooler low temperature as well, making for very pleasant conditions through Sunday morning. By Sunday afternoon, dewpoints will be rising back through the 60s, which is a little more noticeable but still lower than we have experienced in some time.

Surface high pressure over the Great Lakes is bringing a refreshing northerly breeze and lower humidity into the Mid-South as dewpoints above 70 are suppressed to our south (south of the pink line). (

3. Upper level trough means cooler temperatures

As you can see from the map above, high pressure is centered over the Great Lakes so it is cooler than high pressure centered over the Atlantic, like the "Bermuda high" that typically dominates our summer pattern. Coupled with the cooler surface high, the upper levels feature a trough of low pressure over the eastern U.S. We expect cooler temperatures under upper level troughs than upper level ridges (of high pressure). With the trough in place (which, coincidentally, has helped steer Hurricane Hermine northeast around its periphery), below average temperatures continue through Saturday with highs only in the mid 80s. As it weakens, temperatures start to rebound on Sunday and we'll be back to near or slightly above average temperatures in the lower 90s for Sunday and Monday.

At the upper levels, low pressure over the Ohio Valley has resulted in a "valley" or trough south of it, which typically signals cooler than normal temperatures. While it won't last long, it is definitely a welcome pattern for a holiday weekend! (

4. Unfortunately, summer's not necessarily over

Not to be a "Debbie Downer" on this great weekend forecast, but as we head into next week, warmer high pressure at the surface and a ridge aloft will build back into the area as Hermine moves into the western Atlantic. The result? More warm weather and higher humidity, though not to mid-summer levels. Most of next week will feature high temperatures that rise back into the lower 90s with dewpoints in the lower 70s. That's enough to get heat indices back up close to 100°. In addition, a few afternoon thunderstorms will be possible each day, especially the latter half of the week. In the long-term, it looks like another front will move through next weekend (Sept 9-11 timeframe) that will once again cool us back down, hopefully this time out of the 90s for good! Hang in there! Fall is just around the corner, and after the fourth warmest "meteorological summer" (June-August) on record, it can't come soon enough!

And with that, I'll just be going now... Happy Labor Day!

Erik Proseus
MWN Meteorologist

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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder