Friday, October 13, 2017

Trending towards fall... after one more hot day

The past couple of day have provided some evidence that fall is indeed here, while the warmth this afternoon and Saturday remind us that "fall" is relative and includes peaks and valleys.

As opposed to last weekend when hot temperatures (90°+) were coupled with very muggy air, the hottest day (Saturday) before the next fall front arrives (Sunday) will feature dewpoints in the mid 60s instead of the low to mid 70s. So while it'll be quite warm for the Tigers tilt against a formidable-and-respected Navy opponent (forecast highs of 89° are within a degree of the record), a southerly breeze and only-somewhat-uncomfortable humidity levels should make for a bit more tolerable day. Just ignore the calendar and pretend it's early September! [As an aside, I suffered through the weather to revel in a win over UCLA and expect the level of suffering, at least from a weather perspective, to be a bit more muted. As for the outcome of the game... we can only hope that the heat of the day translates to a hot hand on the end of the right arm of one Riley Ferguson.]

The surface map for Saturday shows high pressure to our east ushering in warm air from the south, but a frontal system over the Plains is poised to dive south as a cold front by Sunday morning, bringing relief from the heat. (NWS)
Back to weather... As for what comes next - a return to the fall weather we expect in mid-October! A cold front moves through the Mid-South early Sunday. A warm start turns to off-and-on showers, a gusty north wind, and temperatures that don't move a lot from the morning lows in the upper 60s. Humidity falls on that north wind as temps only peak in the mid 70s. Don't expect a lot of sun, but I also don't expect prolonged rain.

Rainfall amounts associated with Sunday's front taper off from north to south with very small rain amounts expected in the Memphis area. (WxBell)

Precipitation earlier this week helped the dry ground that had developed, but don't expect enough Sunday to continue the trend. No drought indications are currently showing up in west TN or east AR, but parts of north MS have moved into the "abnormally dry" category on the most recent Drought Monitor.
The Drought Monitor shows D0 (abnormally dry) conditions over parts of north MS.
Looking ahead to next week, the first few days post-front look stunning, and the rest of the week doesn't look half bad! Sunny skies pervade as cooler high pressure builds in. Highs for most of the week will be in the 70s (though we might not quite make it there on Monday). Evenings will be cool with low humidity allowing temperatures to drop quickly once the sun sets - which is now getting closer to 6:00 than 7. Mornings will be crisp (I've been waiting to use that word!) with lows near 50° in the city and into the 40s in rural areas. Now THAT is fall!

The American GFS model forecasts temperatures to drop to autumnal levels next week behind Sunday's front. (WxBell)

A slow warming trend takes place  by week's end, though clouds will also start to increase as the next system approaches about a week from now. The good news is that the warmest days behind this weekend's front will be closer to 80° than 90°. Yet another sign that we're nearing Halloween. Enjoy this time of year - before you know it, we'll be complaining about it being too cold!


Keep tabs on the temperature swings and precipitation chances with the MWN mobile app and our social media feeds! Links are provided 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

Monday, October 9, 2017

Humid weather and storm chances - then what?

I don't think many of us were pleased to see the return of summer over the weekend. We can thank the atmosphere surrounding Hurricane Nate for that, as it dragged humid Gulf air into the southern (and in fact, eastern) U.S. That airmass featured dewpoints in the lower 70s and high temperatures in the upper 80s. Which is just miserable for early October if you ask me, especially when most of us (except some lucky folks in Tipton and Fayette Counties) only got enough rain to make a mess of our vehicles.


So what's on deck for the rest of the week? First, maybe some better rain chances. A high pressure airmass that promises some relief will draw closer to start the week, but first an upper level disturbance will trigger scattered showers and thunderstorms in the daytime heat today (and it will be hot - 90° this afternoon with that humidity baked on top). Chances of showers and a few thunderstorms continue overnight.

The morning run of the high-resolution NAM model indicates scattered storms should ignite after 2-3pm in the daytime heat, triggered by an upper-level disturbance. Loop runs from 1pm-10pm. (WxBell via NOAA - click here if it doesn't loop)

By Tuesday, the leading edge of the high pressure system will push a cold front through during the evening hours. Another chance of showers and thunderstorms accompanies the front Tuesday afternoon/evening in continued heat and humidity, as highs again reach near 90°. While severe thunderstorms are not expected today, there is a small chance of a few strong wind gusts on Tuesday. The Storm Prediction Center currently believes the highest risk (which is still fairly low, at "Marginal") is just north of the city. It's worth watching. Overall storm coverage will probably be in the 30-40% range.

The Storm Prediction Center outlook for Tuesday indicates a Marginal (category 1 of 5) Risk of a few severe storms, mainly capable of producing gusty wind, north of Memphis. This outlook could change, stay tuned.

Between today and tomorrow, I'm hoping most of us get some rain, because after that... there's no rain in sight. The cold front will do a good job of pushing the humid air out of the region as dewpoints fall from near 70° tomorrow afternoon to the mid 50s on Wednesday and look to remain there for the rest of the week. It will also be cooler on Wednesday as highs return to "normal" levels in the mid 70s. However, a return of warm temperatures occurs heading towards the weekend as sunny skies and increasingly anomalous pressure levels aloft result in afternoon highs back in the mid 80s after about two days reprieve.

The upper level (500 mb or 18,000') pressure pattern on Friday evening looks more like mid-summer than autumn as anomalously high pressure dominates the eastern 2/3 of the nation. The 594 "circle" over MS is where the high is centered, at a strength that in mid-summer would be capable of producing temperatures in the mid 90s to near 100. Fortunately, it's October... but still will be much warmer than average. (Pivotal Weather)
Looking out a bit further, another cooler airmass looks to arrive in about a week, preceded by a slight chance of rain on Sunday, which should again keep humidity at autumnal levels. However, the signals from the upper atmosphere indicate above normal pressure levels could put a damper on what otherwise would be cool fall weather. We'll have to see how that one plays out, but the last two times I've seen major cool-downs on the horizon (including the one that arrives tomorrow night), they've turned out to be short-lived... The Climate Prediction Center agrees, indicating that week 2 temperatures have a high probability of averaging above normal.

NOAA's Climate Prediction Center outlook for next week indicates a high probability of above normal temperatures. (NOAA/CPC)


Stay tuned to us via social media and our mobile app for the latest forecast information and radar updates. Links are below.

Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook, Twitter, and Google+
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder

Friday, October 6, 2017

September 2017 Climate Data for Memphis, TN

September Climate Recap

After a (relatively speaking) cool August, September continued the trend, as the first two weeks (actually 13 days) were the second coolest on record for that time of year. Every day from the 1st through the 14th registered at or below normal in the temperature department. However, it warmed up quickly during the second half of the month. The period September 15-30 saw no days with below normal temperatures and that period ended up 4th warmest on record. It definitely was a Jekyll and Hyde month!

The consistent part of the weather though was dryness. Less than 2" of rain fell during the month, as the remnants of former Hurricane Harvey moved out on August 31 and despite the remnants of former Hurricane Irma moving over on the 12th, resulting in a record cool day (high of 66°). Nearly 80% of the rain for the month (just over 1.25" at Memphis International Airport) fell on that day, otherwise it was a very dry month. There was no severe weather associated with Irma as there was Harvey in late August, and in fact, no severe weather for the month and no warnings issued.

Memphis International Airport, Memphis, TN


Temperature
Average temperature: 75.4 degrees (0.2 degrees above average)
Average high temperature: 84.8 degrees (0.3 degrees below average)
Average low temperature: 65.9 degrees (0.7 degrees above average)
Warmest temperature: 93 degrees (22nd)
Coolest temperature: 55 degrees (7th)
Heating Degrees Days: 3 (8 below average)
Cooling Degree Days: 321 (5 above average)
Records set or tied: Record cool maximum temperature set on the 12th (66 degrees)
Comments: Ten days recorded temperatures at or above 90 degrees. Year to date, the average temperature of 68.3° is tied for the second warmest on record behind 2012.

Precipitation
Monthly total: 1.61" (1.48" below average)
Days with measurable precipitation: 6
Wettest 24-hour period: 1.27" (12th)
Snowfall: None
Records set or tied: None
Comments:  Only one day recorded precipitation of more than one-half inch. Year to date, precipitation has totaled 38.27" or 99.5% of normal (average year-to-date: 38.47").

Miscellaneous
Peak wind: Northwest/22 mph (1st) (lingering effects of Tropical Depression Harvey)
Average wind: 6.2 mph
Average relative humidity: N/A
Average sky cover: N/A

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

Cirrus Weather Solutions / MemphisWeather.net, Bartlett, TN


Temperature
Average temperature: 72.8 degrees
Average high temperature: 85.5 degrees
Average low temperature: 62.0 degrees
Warmest temperature: 93.5 degrees (21st)
Coolest temperature: 49.8 degrees (7th)
Comments: None

Precipitation
Monthly total: 1.45" (automated rain gauge), 1.58" (manual CoCoRaHS rain gauge)
Days with measurable precipitation: 5
Wettest date: 0.98" (12th) (via automated gauge)
Snowfall: None
Comments: None

Miscellaneous
Peak wind: Northwest/17 mph (1st)
Average relative humidity: 80%
Average barometric pressure: 30.01 in. Hg
Comments: None

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

MWN Forecast Accuracy

MWN average temperature error: 1.14 degrees
MWN forecast temperatures within 2 degrees of actual: 87%
MWN average dewpoint error: 1.70 degrees
MWN forecast dewpoints within 2 degrees of actual: 77%

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

Thursday, October 5, 2017

Will Nate rain on Memphis? And we're still waiting on fall!

For the past 5 weeks or so, our highest rain chances have been with the remnants of tropical systems. First there was Harvey and then Irma. Now Nate is moving onto the radar. While just named as a tropical storm this morning and currently over Nicaragua, it is on a trajectory to take it into the southern Gulf of Mexico by early Saturday, then move quickly north towards an early Sunday landfall along the central Gulf Coast (NOLA? Gulf Shores? Both are possible...). Here's what I had to say earlier today:



Fall Break travelers

If you are planning a fall break trip to the Gulf Coast, particularly the MS, AL, or FL panhandle region, you'll want to keep a close eye on it. As mentioned above, the intensity forecast is problematic. The good news is that it will be fairly compact and moving along at a decent pace, so its impacts won't last long, though after-effects could be an issue (flooding, power outages, etc.). Follow us on Facebook or Twitter for the latest and check out our MWN Tropical page for the latest graphics and NHC bulletins.

Meanwhile, back home...

Locally, we are looking at one more day of warm (mid 80s) but dry weather with low humidity on Friday. By Saturday, southerly flow ahead of an approaching trough will drag moisture from the Gulf of Mexico back into the area and it will be humid again. In addition, the trough and additional moisture will trigger the possibility of scattered showers and a few thunderstorms just about anytime during the day. Temperatures remain warm (mid 80s again), so it'll feel pretty sticky. Keep that in mind if you're heading to the Mempho music festival or other outdoor events like Levitt Shell! Rain chances increase Saturday night and Sunday as Nate's moisture feeds in on the southerly flow. The additional clouds and rain will keep Sunday's temperatures down to near 80.

The European model shows Nate moving from the central Gulf of Mexico on Saturday morning into southeast LA, Mississippi, then the Tennessee Valley by Monday evening. Rainfall is expected across the Mid-South on this track, but wind effects will be minimal. Graphic courtesy WxBell.


Nate's remnants look like they will move east of the Memphis area on Sunday night with continued rain chances, but likely not much of a wind effect. Scattered showers and thunderstorms remain possible Monday with highs back into the mid 80s.

Where's fall??

Earlier this week, I had been fairly confident that we would get a fall front to move through early next week that would knock highs back down into the 70s and deliver some nice fall weather. Well... the large high pressure that would bring that fall weather MAY move by just to our north. While I still expect some relief from the mid 80s and humid weather, we may not get quite as cool as previously advertised and that cooler weather now will be delayed by at least another day or so - to Thursday of next week.


We'll continue to keep our eyes peeled for signs of REAL fall weather, but for now we may have to just be happy that when the humidity creeps up, at least it's not 90 degrees out! Stay tuned to our social feeds for the latest on Nate and its effects on the Gulf coast and our area, as well as the MWN Forecast. And let's hope that this storm is the last one with any impact on the U.S. in what has been a very busy tropical season!

Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook, Twitter, and Google+
Visit MemphisWeather.net on the web or m.memphisweather.net on your mobile phone.
Download our iPhone or Android apps, featuring StormWatch+ severe weather alerts!
MWN is a NOAA Weather Ready Nation Ambassador Meteorologist Erik Proseus is an NWA Digital Seal Holder