Sunday, June 13, 2021

Relief from falling water - from the sky and our brows!

Last weekend on this blog, we correctly forecast a wet pattern for this past week, though we didn't expect to see 10-15" of rain across sections of southeast AR into northern MS! Meanwhile, those of us north of I-40 (or so) enjoyed tolerable rain amounts most days that helped green up our Bermuda lawns! 

Departure from average rainfall amounts for this past week show nearly a foot of rain above average across north MS and southeast AR. In west TN, near average in the metro but below average just to our north. (WxBell) 

We also correctly identified our first 90-degree temperature of the year occurring in the past couple of days. However, one thing we missed on last weekend was this statement regarding this (current) weekend's weather: "...a push of drier air into the region that will bring relief from high dewpoints and a breath of fresh air from the north." Oops! While the temperature and scattered thunderstorm prediction we also made was correct, the front that has passed through has done nothing for the humidity (yet)!

The week ahead - sunshine and low humidity

About that "(yet)" mentioned above... perhaps the week-ahead models were just off a couple days. Starting tomorrow, we will finally feel the effects of drier air that is pushing south behind this weekend's cold front. Dewpoints, which are a direct measure of the amount of moisture in the air, will fall from the mid 70s to near 80 in some spots this weekend (oppressive!), to the 60s Monday and then maybe the 50s by mid-week (very pleasant!).

The Muggy Meter for Tuesday afternoon shows dewpoints 10-15 degrees cooler than this weekend!

In addition, a dry pattern sets up as high pressure at the surface builds in from the north and aloft from the west, while a trough of low pressure settles into the eastern U.S. This pattern results in slightly cooler temperatures (mainly 80s during the days and 60s at night), lower humidity, and abundant sunshine. I believe the farmers and others flooded out to our south this past week will gladly take that forecast!

The mid-level pressure pattern and departures from normal for this week from the European ensemble shows a massive ridge of high pressure over the western U.S. extending east to the Mississippi Valley, while a trough of low pressure sits over the eastern seaboard. (WxBell)

The surface weather pattern on Wednesday morning, according to the European ensemble, shows high pressure over the Great Lakes extending well south with drier and cooler than average flow around it. (WxBell)

Next weekend - tropics get the attention

By next weekend, eyes will be turning south as a tropical disturbance could be moving towards the western or central Gulf coast. While it's still early, indications are that an area of showers and storms will remain fairly disorganized well south in the Bay of Campeche, off the Mexican coast south of the TX coastline, into mid-week. After that, it could start to move north and perhaps organize a bit. It's entirely too early to make any predictions, but the western to central Gulf coast (TX, LA, MS, AL) could see a fair amount of rain from this system next weekend into early the following week and it's conceivable that a tropical storm could bring gusty wind to the coast in that timeframe as well. 

The National Hurricane Center (NHC) is keeping a close eye on a disturbance in the Bay Of Campeche. It currently poses no threat to the U.S., but by mid-week could start moving north bringing rain to the western Gulf coast. (NOAA/NHC)

For now, it looks to have little to no impact on the Mid-South for the next 7 days, though another frontal system is more likely to bring precipitation chances back to the Mid-South next weekend with humidity increasing as well. Stay tuned!



Erik Proseus
MWN Meteorologist

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Sunday, June 6, 2021

Pesky upper low brings a wet & muggy pattern this week

The average first occurrence of 90 degrees in Memphis is May 24. This afternoon as I type this, on June 6, the temperature is 76 under cloudy skies with scattered showers over the region. We hit 89 twice near the end of May and really have not threatened it so far in June. And as you'll see from the forecast below, it's not likely to happen this work week either. Three cheers for less A/C (if you can tolerate the humidity that has arrived in its place)!

Atmospheric Overview

A large upper level low pressure system over the Southern Plains the past few days will lift slowly northeast into Missouri on Monday, then into the Ohio Valley mid-week as it weakens. A trough will extend south from the low into the Mid-South early this week before shifting east as high pressure aloft builds into the area from the southwest behind the weakened and departing low. 

This pattern has pushed summer heat well to our north - into the Northern Plains and east into the Northeast U.S. where highs are reaching the 90s to near 100 degrees in spots! Meanwhile, scattered to widespread showers and embedded heating-of-the-day thunderstorms cover the south-central portion of the country with rain chances having spread east into the southeaster U.S. this weekend. As the upper low shifts east, so do the higher rain chances, before diminishing later this week as high pressure overhead starts to regain control. Let's walk through the week day-by-day...

The upper level pressure pattern from the European model ensemble through Friday evening shows an upper level low weakening and lifting northeast this week, replaced by higher pressure. The blue colors indicate anomalously low pressure, while the orange anomalously high. (WeatherBell) 


Monday

Rain has been relatively hit and miss this weekend and I expect that trend to continue into Monday with scattered showers and thunderstorms during the warmer part of the day and lingering showers into the evening. You may or may not get wet - it's impossible to predict where and when the rain falls. However, we can be sure that southerly wind keeps the dewpoints elevated at or above 70, which is high enough to ruin your hair-do and considered very muggy. After a morning low near 70, afternoon highs reach the low 80s.



Tuesday-Wednesday

With the weakening upper low passing by to our north and the trough passing through our area, rain chances are a bit higher (in the 60-70% range) and may include more of the overnight hours as well, though any thunderstorms that occur are more likely to be in the afternoon/evening hours when peak heating occurs. Humidity remains gross as southerly wind continues to fetch Gulf moisture and throw it over the region. Lows remain at or above 70 (which honestly isn't that low) and highs top out in the low to mid 80s. 


Thursday-Friday

As the low starts to move away to our east, high pressure aloft takes its place. However, lingering humidity and a bit more heating thanks to some sunshine breaking through means scattered shower and thunderstorm chances continue, though at lower probabilities (50% Thursday and about 30% Friday, as of now). Precipitation totals through Friday morning could reach the 2-3" range after multiple days of elevated rain chances, though the scattered nature on at least a couple of days could mean wide variances from place to place.

Forecast rainfall through Friday morning from the NWS Weather Prediction Center. 2-3" will be common across the Mid-South. (PivotalWx)

High temps will likely reach near average values in the upper 80s by Friday. With dewpoints remaining uncomfortably high, you should make sure your deodorant supply is in good shape to start the week. 



Next weekend

Early signs point to a bit of relief Saturday in the form of a cool front. If models are correct (that may be a 50/50 proposition six days out, but there is at least some agreement amongst them), then we'll see one more day of scattered thunderstorms. But we'd also receive a push of drier air into the region that will bring relief from high dewpoints and a breath of fresh air from the north, leading to a dry Sunday. 

One thing to consider though is that it won't necessarily be cooler behind the front. In fact, high pressure aloft looks like it might continue to build, so there's a decent chance that by next Sunday afternoon we will be looking the first 90-degree temperature of the year squarely in the eyes. And by mid-June, it's not only almost 3 weeks behind, but also perfectly normal to see 90 every day for a couple of months. Summer is on the horizon!



Erik Proseus
MWN Meteorologist

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Follow MWN on Facebook and Twitter for routine updates and the latest info!
Complete MWN Forecast: MemphisWeather.net on the mobile web or via the MWN mobile app
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