Thursday, October 24, 2019

Wet weather to start the weekend and a chilly Halloween setting up!

Fall is now in full force! Over the past couple of days we have had some beautiful fall days with a few chilly mornings and nights thrown in. This time of year, we often get some severe storms associated with cold fronts moving in after several days of warmer temperatures. This was the case Monday morning. Monday’s cold front brought some severe storms early but wonderful fall days since.

Over the next week there will be a few more chances at rain. Into Friday and Saturday, a Gulf low pressure system will bring increasing rain chances for the beginning of the weekend. Sunday through Tuesday will be more of the cooler mornings and warmer afternoons that we have been seeing a lot of recently! By mid-week, another cold front will move across the southeast bringing a cold punch just in time for Halloween!  

Thursday night through Saturday

Clouds will increase overnight into Friday morning. By late Friday morning, rain chances return as a low pressure system moves in from the Gulf of Mexico. This tropical system will bring moisture and rain chances through Saturday. Temperatures on Friday will only reach about 60 and only fluctuate slightly overnight into Saturday morning. By Saturday early afternoon, rain chances should fall off allowing for temperatures to reach back up into the upper 60s. Overall Friday looks messy and cool while Saturday may recover and allow for a partially nice day!
The NWS forecast for precipitation from this low-pressure system, valid Friday to Saturday night, indicates a good bit of rain overall with over 2" possible for some areas. (WPC)


Sunday through Tuesday looks beautiful! Overnight temperatures heading into Sunday will be in the lower 50s and will quickly rise into the upper 60s by afternoon. Behind the low pressure system, skies will be mostly sunny with no rain chances. Monday and Tuesday look very similar with overnight lows around 50 and highs in the upper 60s under sunny skies. Tuesday may be slightly cooler with afternoon highs only reaching into the mid 60s. Overall the beginning half of next week looks like cool fall days!


Wednesday brings the next cold front through the area. This front should have low chances of strong storms, but it will bring back rain chances. The front should pass early Wednesday bringing much cooler temperatures for the afternoon. Highs will only be in the mid 50s under mostly cloudy skies throughout most of the day. 

The surface map for Wednesday morning shows a strong fall front moving through the Southeast. Storms are unlikely with this frontal passage but the coldest air so far this fall will be behind it. (WPC)
Into Halloween on Thursday, skies will clear but the cold air will still be hanging around. Afternoon temperatures may only reach the lower 50s with overnight lows getting down into the 30s! As you head out with the kids to trick or treat you may need to bundle up! With this latest cold front, we may have a shot at our first widespread frost of the year by late week.

A Look at Week 2 

Over the following 8-10 days, it appears we will be in the same trend that we have be experiencing for the past couple of weeks. Temperatures will be pretty chilly to end the month. Models are trying to put the next cold front late next weekend to start off November much cooler than how we started October. As we get closer the models will become more confident on the strength and timing.  Overall it appears that we will remain slightly below average throughout the first half of November.  

The temperature outlook (relative to average) for October 31 - November 6 indicates much of the country east of the Rockies will be cooler than normal. (CPC)

Paige Davide
MWN Meteorologist Intern

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Monday, October 21, 2019

Severe storms rumble through the Mid-South early Monday

A squall line of strong to severe storms moved quickly through the Mid-South, including the Memphis metropolitan area, as rush hour began Monday morning. A Tornado Watch was issued shortly after 3am for most of the metro as two lines moved through western and central AR.

Just before 6am, the first Tornado Warning was issued for southern Mississippi County, AR, just west of Tipton County. This was the first sign (locally) that the squall line was capable of producing brief, "spin-up" tornadoes that sometimes occur in severe squalls, verifying forecasts from the previous day that the scenario was plausible.

About the same time, a Severe Thunderstorm Warning was issued for the western half of the metro, including western Shelby County. Over the next two hours, the line crossed the entire metro, then weakened considerably when it reached central Fayette County.

In those intervening hours, no less than four Tornado Warnings were issued in the metro - one in northern Tipton County, one in northern Shelby County, one in southeast Memphis, and one in central Fayette County. Radar showed low-level wind rotation in each, but the southern Shelby storm is the one most likely to have produced a tornado.

Wind damage began near Memphis International Airport with trees and limbs down on the west side of the airport, windows blown out in the airport terminal, and damage just east of the airport. The storm's path east-northeast took it parallel to I-240 through Parkway Village, along SR 385 into Hickory Hill, and then into parts of west Germantown near Poplar and Poplar Pike. There were many reports trees down or uprooted, damage to structures (perhaps the worst of which was in the Cottonwood Apartments), and utility poles snapped with wires down. See our Twitter timeline for many reports and photos.

There was also radar evidence of a possible tornado in the form of a "debris ball" - a radar signature that indicates that debris is being lofted into the storm and detected by the radar beam.

MLGW reported that over 43,000 customers (which amounts to more than 100,000 people) lost power during the storms. Scattered traffic light outages were spread across the city. The official peak wind gust at Memphis International Airport was 53 mph, but the storm intensified as it moved east of the airport and rotation in the storm tightened. As of this writing, we are unaware of any major injuries.

An official report from the National Weather Service indicates that the storm produced a preliminary EF-1 rated tornado with maximum wind of 105 mph. Radar evidence and storm damage supports the ground evidence of a tornado. These "QLCS (quasi-linear convective system) tornadoes" - or those that spin up in a squall line and last a short period of time - are very difficult to provide much warning lead time on and frequently are missed completely until after they have done their damage. Fortunately, they also tend to produce damage on the low end of the tornado scale, but that doesn't mean that if one affects you it was no big deal. It is for those affected.

A word on "unexpected" storms

Inevitably after a storm that produces damage, we hear that the storm "hit without warning" or was "unexpected." It happened again this morning when MLGW issued a press release calling the storm unexpected.

I understand that there is damage control that must be done when 10% of your customer base loses power. I also understand that perhaps the storm packed more of a punch than what some may have been "expecting." But the presence of a squall line was not unexpected, nor was the timing, nor should have been the potential intensity.

The National Weather Service first mentioned the possibility of Monday's strong storms last Wednesday morning in their Hazardous Weather Outlook - a full five days in advance. By Saturday morning, they had increased their concern level:

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Strong to severe storms are possible on Monday as a cold front 
moves across the Mid-South. Damaging winds, large hail, and
isolated tornadoes will be possible. In addition, heavy rainfall
could lead to flash flooding.

On Sunday, areas along and east of the Mississippi River were included in a Slight Risk (level 2/5) for severe weather on Monday by the Storm Prediction Center. As high-resolution model data got within range of the event, we also posted detailed information Sunday afternoon that had the timing within an hour of the actual event and the mention of a line of storms with damaging wind as the chief concern and an isolated tornado possible. The confidence level was assigned "moderate to high."

By 3am, a Tornado Watch was issued and the line was evident on radar in AR with a history of producing well-publicized tornadoes in the Dallas area. Severe Thunderstorm Warnings were issued well in advance of the line. Tornado Warnings were issued as quickly as possible once rotational signatures became evident.

In my opinion, the squall line was not only NOT unexpected, it was well forecast - down to the hour nearly a day in advance. The potential impact was stated clearly and unequivocally. There is no way to know where and when a tornado will touch down more than minutes in advance. But the possibilities are enumerable and were communicated. Damaging wind was clearly identified as a hazard. It's time to tell it like it is... "a storm system that was well-forecast produced damage that was in line with the potential reasonable worst case scenario and we're doing everything we can to resolve the issues."

No one (in their right mind anyway) expects 43,000 customers to have power restored instantaneously. We just expect hard work towards executing a well-conceived, predefined contingency plan with strong communication on how that plan is evolving throughout the process. I happen to believe MLGW is executing that plan and appreciate the "Memphis grit" that the front line workers are displaying as they work to restore power. Let's not insult the weather community that did an exemplary job attempting to communicate the threat by calling it unexpected.

Erik Proseus
MWN Meteorologist

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Friday, October 18, 2019

Fall weather is in full force! Looking ahead to the second half of October...

It seemed like fall took a while to get here! The 90s hung on into early October, following the warmest September on record, but now the tide has turned and the usual roller coaster of the changing seasons has arrived!

We've been alternating between cool mornings and warm afternoons with a front every several days that brings decent rainfall - much appreciated after briefly entering a moderate drought to start the month. As we head into the back half of October, mild temperatures will continue with regular frontal passages bringing bouts of rain and some storms. Let's get into it!

Saturday and Sunday

Very pleasant fall weather continues from Friday into the weekend, which is good news for Tiger football fans, Mempho Music Festival attendees, and probably most of the rest of you! Earlier in the week there was some concern about a system in the Gulf of Mexico bringing some rain Saturday. That system, now Tropical Storm Nestor, will safely slide by to our southeast.

Tropical Storm Nestor formed today in the Gulf of Mexico but will be short-lived and have no effect on Mid-South weather outside of some cloud cover.  (NHC)

We'll see some high cloud cover at times, but temperatures should be, well, temperate! Mid 70s Saturday and near 80 Sunday with slowly increasing humidity as wind turns southerly. Morning lows will generally be in the 50s, though a few 40s are possible in cooler areas Saturday early morning.

Sunday night and Monday

The next big frontal system approaches Sunday night, bringing the potential for a few sporadic showers late in the day Sunday and into the overnight hours. With southerly wind, it'll get more muggy and warm Sunday night as lows stay in the 60s. The front is progressive - meaning it will move through quickly and completely, not have a political agenda...

It will bring a fairly substantial round of rainfall on Monday, but end just as quickly. Right now, the morning hours including rush hour look to be much wetter than the afternoon or evening. In fact, the system may be east of us by Monday afternoon with skies clearing by late afternoon.

The surface map for Monday morning shows a strong fall front bearing down on the Mississippi Valley. Thunderstorms are likely along and ahead of it Monday morning, followed by a few more nice fall days! (WPC)

The NWS forecast for precipitation from this front, valid Sunday night and Monday, indicates a good deal of rain in a relatively short period. 1-2" is likely, mostly Monday morning. (WPC)

There are also likely to be some thunderstorms as dewpoints recover into the 60s ahead of the front. Instability will be fairly low, but wind shear will be high, which is typical for this time of year. Storms could pack a brief punch with some gusty wind not out of the question.

Areas east of the Mississippi River are currently forecast in a severe weather risk that equates to "Slight" (or level 2 of 5) on the Storm Prediction Center scale. This could change though by Monday, so well provide daily updates on our social media feeds. After a warm start, temperatures may actually fall a bit behind the front Monday but should still remain mild with a breezy wind shifting to the northwest.

The Storm Prediction Center places areas east of the Mississippi River in the Mid-South under a Slight Risk of severe weather on Monday with strong wind gusts the most likely impact. There is currently a 15% chance of severe weather within the metro. (SPC)

Tuesday through Thursday

Once again, the Mid-South will enjoy lovely fall weather between fronts with mild temperatures that peak in the 60s to near 70 degrees in the afternoon and drop into the 40s at night. We should also see plenty of sunshine, which will help dry things out after a good dose of rain Monday.

End of the week through end of the month

The next system approaches Friday-ish with models still needing some time to come to a unified solution. It doesn't appear that we'll have as strong of a "recovery" of the atmosphere ahead of the late week system, so severe weather chances look minimal. Overall, a cooler than average pattern looks to continue from the middle of next week to the end of the month. Any early guess at Halloween puts fairly strong odds on a cooler pattern than one where we're all sweating by the end of the trick-or-treating rounds!

The temperature outlook (relative to average) for October 26 - November 1 indicates much of the country east of the Rockies will be cooler than normal. (CPC)

Erik Proseus
MWN Meteorologist

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Wednesday, October 9, 2019

September 2019 Climate Data for Memphis, TN

September Climate Recap

Temperatures usually start receding in September as summer gives way to early fall. That was not the case this year though, as September ended up as the hottest on record and a degree warmer on average than August. Only two days failed to reach 90 degrees and the coolest night was a balmy 68 degrees, resulting in an average temperature for the month that was more than 8 degrees above normal. The warmth was prevalent across much of the eastern three-fourths of the nation.

Average temperature anomalies for the U.S. in September show a hot month for most locations east of the Rocky Mountains, while cool weather covered areas west of the Rockies. (NWS data via WeatherBell)

What had been a wet year to this point "self-corrected" to an extent in September with one of the driest months in recent history. In fact, with just over one-tenth of an inch of rain, it was the third driest September on record! Coupled with the record heat, drought conditions quickly developed with a classification of "moderate" for parts of the metro (see below). Measurable rain only fell on two days in September at the airport. There was no severe weather in September.

Memphis International Airport, Memphis, TN

Average temperature: 83.5 degrees (8.3 degrees above average)
Average high temperature: 93.7 degrees (8.6 degrees above average)
Average low temperature: 73.3 degrees (8.1 degrees above average)
Warmest temperature: 100 degrees (16th)
Coolest temperature: 68 degrees (24th)
Heating Degrees Days: 0 (11 below average)
Cooling Degree Days: 564 (248 above  average)
Records set or tied: Hottest September on record. Daily record high temperatures set on the 17th (99) and 18th (99), and tied on the 27th (95).
Comments: 28 days recorded a high temperature of 90 degrees or warmer, 7.7 days more than the average for the month and a September record.

Monthly total: 0.12" (2.97" below average)
Days with measurable precipitation: 2 (5.3 days below average)
Wettest 24-hour period: 0.10" (23rd)
Snowfall: None
Records set or tied: None
Comments: The month was the 3rd driest September on record in Memphis.

Peak wind: West/58 mph (13th)
Average wind: 5.4 mph
Average relative humidity: 73%
Average sky cover: 50%

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

Cirrus Weather Solutions /, Bartlett, TN

Average temperature: 80.6 degrees
Average high temperature: 95.0 degrees
Average low temperature: 68.5 degrees
Warmest temperature: 100.1 degrees (16th)
Coolest temperature: 64.0 degrees (6th)
Comments: Temperature data was only recorded through the 23rd of the month due to station relocation.

Monthly total: 0.22" (automated rain gauge), 0.26" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 2
Wettest date: 0.15" (23rd) (via automated gauge)
Snowfall: None
Comments: Precipitation data was available for the entirety of the month of September.

Peak wind: South/18 mph (20th)
Average relative humidity: 74%
Average barometric pressure: 30.06 in. Hg
Comments: The above data was only recorded through the 23rd of the month due to station relocation.

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

MWN Forecast Accuracy

MWN average temperature error: 1.61 degrees
MWN forecast temperatures within 2 degrees of actual: 76%
MWN average dewpoint error: 1.95 degrees
MWN forecast dewpoints within 2 degrees of actual: 72%

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

Climate Outlook - October

The October climate outlook for the United State from the Climate Prediction Center is shown below. Below average temperatures are expected across the Pacific Northwest and Northern Rockies. Above normal temperatures are likely to be found in the southern and eastern U.S., most pronounced in the southeast. Odds favor above average temperatures for Memphis in October. Memphis averages 64.1 degrees for the month, or about ten degrees cooler than September.

A wet October is forecast for the northern tier of the country, particularly the Midwest and Upper Mississippi Valley. Drier than average conditions are forecast across the southeast U.S. For Memphis, odds favor slightly below average rainfall, which historically results in right at four inches in October.

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Complete MWN Forecast: on the mobile web or via the MWN mobile app
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MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder