Saturday, August 19, 2017

Eclipse forecast and viewing details, and an early taste of fall?

I've got some good news and some great news in the forecast... but first the forecast you're most interested in - the eclipse forecast, which is our good news!

So, are we gonna see the eclipse?

The short answer: yes!

An upper level ridge of high pressure will exercise its influence on the forecast through early next week, including Monday. What does that mean? Summer-like conditions. Heat and humidity this weekend will continue into Monday as heat indices peak in the 102-105° range each afternoon. I can't rule out a few stray thunderstorms, but not everyone will see rain. Most of these showers or thunderstorms don't really get started until 2pm or later.

So for Monday I expect partly cloudy skies (those white puffy clouds that only temporarily block the sun) and mainly dry conditions. It will be HOT with temperatures near 90° at 1:23pm Monday and a heat index above 100°. Plan accordingly.

I wrote a complete "Viewing Guide" to the eclipse that I encourage you to read if you haven't. Since then I've seen some misinformation about a few things related to eclipse viewing. My Facebook post from yesterday addresses those:

Viewing Safety

So to be clear, you only need to wear eclipse glasses when you are wanting to view the sun directly. You don't need them when you're outside on Monday for normal activities (though sunglasses will probably be in order like any other summer day!). And here in the Mid-South you should NOT look at the sun Monday (or any other day for that matter) without eclipse glasses! The only time that you can view an eclipse without eclipse glasses is during totality, and that won't happen here.

I understand that Pink Palace and American Paper Optics in Bartlett are the only places left that have NASA-approved glasses and are selling them this weekend. Prepare to pay $3-5 a pair for them and also prepare for long lines! If you can't get glasses, there are a couple of "old-school" ways to view the eclipse. My friend Ryan Vaughan of KAIT-TV in Jonesboro shows how to make a viewer out of a cereal box and meteorologist Brad Panovich explains how to use two pieces or cardboard or stiff paper to make an eclipse projector. Also, here's a really good video tip on taking pictures of the sun with a zoom lens and no filter!

Now the great news... 

A cold front will move through this coming Wednesday and it's a doozy! Unlike the fronts of the past couple weeks that provided some short-term relief but returned north and put us back in the soup, this one looks to have some staying power. Look for an increase in thunderstorm coverage a bit on Tuesday as the front gets closer, then a high chance of thunderstorms on Wednesday as it moves through. Once the front clears though, we'll see a significant drop in the humidity levels on Thursday and temperatures that also respond by falling into the mid 80s for highs, with lows that could get down to 60° outside the city by the end of the week and into next weekend.

In fact, the week 2 outlook from NOAA that I posted yesterday shows a good chance of below normal temperatures for the end of August and beginning of September! Could this be the end of 100° heat indices for this summer? I'm not quite ready to go there yet, as we can get some hot days in September, but I do think we'll be getting out first taste of early fall by the end of the week. In honor of the now-recovering Rick Flair, can I get a...

The most recent forecast details and additional cool eclipse tips will be posted on our social media feeds listed below, and you can always get the latest forecast info on our website, mobile web, and mobile app, also linked below.

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

Sunday, August 13, 2017

Summer takes another break, but makes a comeback this week

It's been kind of a strange summer. Certainly not overly hot other than a brief stint in mid-late July. In fact, since July 28, we've now had 16 consecutive days of below average daily temperatures and that will be extended at least three more days as we head into mid-August!

You can thank a series of fronts over the past couple of weeks that have moved over and through the metro for the additional cloud cover, periods of acceptable humidity levels, and scattered rainfall. That trend will continue as we head into the work and school week. The closest front is to our south but it is very weak, so wind direction is variable to southeasterly. As your Sunday progresses, a mesoscale convective vortex (MCV), or remnant weak low pressure left behind by a previous thunderstorm complex, will move across the Mid-South from the west as upper level flow pushes it east-northeast. This will bring a good chance of rain to the area later this afternoon and into the nighttime hours.

Simulated radar from the HRRR model through the early morning hours on Monday shows a large slug of moisture moving across the metro later this afternoon and into the early nighttime hours. You'll notice the distinct "spin" in the area of potential thunderstorms on the back side of the rain area. That is the low pressure system driving the precip, what we call a mesoscale convective vortex (MCV). (WxBell) 

A few thunderstorms are possible, mainly south of the city where a Marginal Risk (level 1/5) of severe weather exists. I do not expect to see any strong storms in the metro. Rainfall totals could rise to a half-inch to inch in some spots by Monday morning.

A low-end severe weather risk exists for the far southern portions of the metro today. I expect no severe weather for most of the metro and only a low chance of thunder north of the MS/TN state line.

The week ahead

In the wake of the rain today and tonight, Monday looks to be drier though a chance of storms is in the offing, mainly south of the city. Though humidity will be back in the "muggy" category, temperatures remain mild with highs in the mid 80s due to only partly sunny skies.

Additional scattered showers and thunderstorms will be possible nearly each day throughout the week and into next weekend, although not everyone will see rain every day. In fact, rain chances diminish some mid-week as upper level high pressure begins to build to our south and push north a bit. That will squash rain chances a bit, leaving a few possible in the heat of the day.

Speaking of heat, it's making a comeback under this high as well. We'll be back above 90° by Wednesday with dewpoints getting closer to the "miserable" range as they near 75°. That'll mean heat indices back above 100° and overnight lows that get no lower than the mid 70s. The mugginess could subside a bit by next weekend as the pattern shifts just a bit, but typical summer weather will continue right into the weekend.

Forecast temperatures for the next 10 days from the National Weather Service "National Blend of Models" (NBM), which averages today multiple models to depict the best possible forecast using them all. (WxBell)

Eclipse Forecast

I know everyone's keen interest is on the eclipse forecast a week from tomorrow, August 21. Eight days out can still be a crap shoot as far as cloud forecasts, but the overall pattern doesn't necessarily bode well. Of course, a couple hours of partly cloudy skies is all we need, but it doesn't appear Eclipse Day will be a bright sunny day dominated by high pressure at all levels. Stay tuned and cross those fingers!! Starting tomorrow, eclipse day will be in the extended range forecast on your MWN app!

For more on viewing the eclipse in the Memphis area, see our Viewing Guide if you haven't already!

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

Saturday, August 12, 2017

July 2017 Climate Data for Memphis, TN

July Climate Recap

After consecutive months of below average temperatures, an anomaly in recent history, July moved back above average, but just barely. The average temperature of 83.1 degrees was about one-half degree above normal. The month as marked by a very hot spell in the third week of the month with mid to upper 90s on several consecutive days and Excessive Heat Warnings posted as heat indices climbed above 110 degrees. Slightly cooler than average weather started and ended the month.

Precipitation was fairly variable across the metro due to the nature of summertime thunderstorms. To wit, Memphis International Airport ended up with just under 4" of rain and at a deficit for the month, while MWN in Bartlett recorded over 5", which was above the July average. Most of the rain fell in the early and latter stages of the month with a hot spell mid-month resulting in little precipitation. Another example of the sporadic nature of the precipitation lies in the storm reports for the month. Flash flooding was reported in multiple locations in the metro on the 15th, yet both Memphis International Airport and MWN recorded no measurable precipitation for the date. A couple of hail and wind reports were recorded with pulse thunderstorms on various days of the month but no widespread severe weather occurred.

Memphis International Airport, Memphis, TN

Average temperature: 83.1 degrees (0.4 degrees above average)
Average high temperature: 92.3 degrees (0.7 degrees above average)
Average low temperature: 73.9 degrees (0.1 degrees above average)
Warmest temperature: 99 degrees (21st)
Coolest temperature: 67 degrees (30th)
Heating Degrees Days: 0 (0 above average)
Cooling Degree Days: 571 (22 above average)
Records set or tied: None
Comments: 23 days recorded temperatures at or above 90 degrees, which is 2 more than an average July. Year to date, the average temperature of 65.7° remains the second warmest on record behind 2012.

Monthly total: 3.91" (0.68" below average)
Days with measurable precipitation: 8 (0.8 days below average)
Wettest 24-hour period: 1.50" (23rd)
Snowfall: None
Records set or tied: None
Comments: Year to date, precipitation has totaled 27.37" or 84% of normal.

Peak wind: North-northeast/33 mph (14th)
Average wind: 6.3 mph
Average relative humidity: 73%
Average sky cover: 40%

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

Cirrus Weather Solutions /, Bartlett, TN

Average temperature: 81.5 degrees
Average high temperature: 92.3 degrees
Average low temperature: 71.7 degrees
Warmest temperature: 98.7 degrees (22nd)
Coolest temperature: 61.1 degrees (30th)
Comments: None

Monthly total: 5.18" (automated rain gauge), 5.26" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 9
Wettest date: 1.26" (28th) (via automated gauge)
Snowfall: None
Comments: No measurable rain fell from the 9th-22nd, nearly two weeks.

Peak wind: Northwest/27 mph (1st)
Average relative humidity: 79%
Average barometric pressure: 30.00 in. Hg
Comments: None

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

MWN Forecast Accuracy

MWN average temperature error: 1.27 degrees (tied for most accurate month of forecasts in 20 years of record-keeping!)
MWN forecast temperatures within 2 degrees of actual: 87%
MWN average dewpoint error: 2.02 degrees
MWN forecast dewpoints within 2 degrees of actual: 68%

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