Severe weather outlook for Friday and Saturday

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN / MEMPHISWEATHER.NET
633 AM CDT FRI MAY 9 2008

...A SIGNIFICANT SEVERE WEATHER OUTBREAK IS POSSIBLE ACROSS PARTS OF THE MID SOUTH SATURDAY AFTERNOON AND SATURDAY NIGHT...

...THE MEMPHIS METRO AREA HAS BEEN PLACED UNDER A MODERATE RISK OF SEVERE WEATHER FOR SATURDAY AFTERNOON AND SATURDAY NIGHT...

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY AND MOVE INTO THE MIDDLE MISSISSIPPI VALLEY SATURDAY NIGHT WHILE A WARM FRONT SURGES NORTHWARD INTO THE MID SOUTH. THIS WILL BRING A WARM...MOIST...AND UNSTABLE AIRMASS INTO THE REGION AHEAD OF A STRONG COLD FRONT THAT WILL APPROACH FROM THE WEST. SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP WELL AHEAD OF THE COLD FRONT...NEAR THE WARM FRONT...SATURDAY AFTERNOON AND EARLY EVENING. AN ADDITIONAL LINE OF SEVERE THUNDERSTORMS WILL LIKELY DEVELOP ALONG AND IMMEDIATELY IN ADVANCE OF THE COLD FRONT AS IT MOVES ACROSS THE AREA SATURDAY NIGHT...BETWEEN 8PM AND 2AM. THE MAIN THREATS WILL BE DAMAGING WINDS...LARGE HAIL...AND TORNADOES. THE POTENTIAL WILL ALSO EXIST FOR A FEW STRONG TORNADOES.

ALSO BE AWARE THAT THE MID-SOUTH IS UNDER A SLIGHT RISK FOR SEVERE WEATHER THIS AFTERNOON AND EVENING. WHILE ONLY ISOLATED STORMS ARE EXPECTED TO DEVELOP...UPPER LEVEL DYNAMICS COULD CAUSE ANY STORM THAT FORMS TO BECOME SEVERE RAPIDLY. DAMAGING WIND...LARGE HAIL...AND ISOLATED TORNADOES ARE ALL POSSIBLE DURING THE PEAK HEATING HOURS FROM 2-10PM TODAY.

MID-SOUTHERNERS SHOULD KEEP IN TOUCH WITH THE LATEST WEATHER INFORMATION CONCERNING THESE DEVELOPING SEVERE WEATHER THREATS. MEMPHISWEATHER.NET WILL KEEP YOU UPDATED ON THE LATEST EVENTS AS THEY UNFOLD.
$$

SJM/EAP

NE Mississippi twister caught on camera!

Wow! What a storm! This picture was taken by fellow weather nut Jeff W. Williams near Booneville, MS in a town called Jumpertown at 6:49pm on May 2. He is a friend of mine that owns a personal weather station that sits right where this picture was taken from - about 2 miles SE of the tornado. Later that evening, another storm with 1" hail passed overhead and damaged his station's anemometer. That's what I call too close for comfort! Jeff indicates this was his first tornado sighting and the slight blurriness in the picture is owed to his hands shaking from nervousness!

That afternoon and evening scores of storms, some supercellular, ripped through eastern Arkansas, north Mississippi, and west Tennessee, dropping several tornadoes like the one picture above. The tornado above was classified EF-1 by the National Weather Service. The biggest storm of the day produced an EF-3 twister that devastated the town of Earle, AR in northwest Crittenden County, 25nm WNW of downtown Memphis.

Air Quality Awareness Week - Tuesday

AIR QUALITY CAN VARY...DEPENDING ON HOW MUCH AIR POLLUTION IS PRODUCED IN YOUR COMMUNITY...HOW MUCH POLLUTION IS CARRIED INTO YOUR COMMUNITY BY THE WIND...AND BY WEATHER CONDITIONS.

OZONE FORMS WHEN TWO GROUPS OF KEY POLLUTANTS...NITROGEN OXIDES AND VOLATILE ORGANIC COMPOUNDS...COOK IN THE SUN. FOR EXAMPLE...PARTICULATE MATTER CAN BE DIRECTLY EMITTED IN SMOKE FROM A WOODSTOVE...BUT A LOT OF PARTICLES FORM WHEN GASES REACT IN THE AIR. NITROGEN OXIDES AND SULFUR DIOXIDES CONTRIBUTE TO PARTICULATE MATTER FORMATION.

THESE OZONE AND PARTICLE FORMING POLLUTANTS COME FROM A WIDE VARIETY OF SOURCES...INCLUDING CARS...TRUCKS...BUSES...POWER PLANTS...AND INDUSTRIES. NATURAL SOURCES SUCH AS WILDFIRES AND DUSTSTORMS CONTRIBUTE TO PARTICULATE MATTER POLLUTION. TREES AND OTHER VEGETATION ALSO EMIT ORGANIC COMPOUNDS THAT CONTRIBUTE TO PARTICULATE MATTER AND OZONE POLLUTION.

WEATHER PLAYS A BIG ROLE IN THE LEVELS OF OZONE AND PARTICULATE MATTER POLLUTION IN YOUR COMMUNITY. SUNLIGHT AND HEAT PROMOTE OZONE FORMATION. LIGHT WINDS AND TEMPERATURE INVERSIONS CAN KEEP POLLUTION CONCENTRATED NEAR THE GROUND. DEPENDING ON ITS DIRECTION...THE WIND CAN BRING IN MORE POLLUTION...SOMETIMES FROM HUNDREDS OF MILES AWAY.

TOMORROW WE WILL LEARN ABOUT THE HEALTH IMPACTS OF POOR AIR QUALITY.

...courtesy NWS/Memphis

Air Quality Awareness week - Monday

THIS WEEK MARKS THE BEGINNING OF OZONE SEASON FOR MANY AREAS IN THE UNITED STATES. IN THE MID-SOUTH THE OZONE SEASON OCCURS FROM APRIL 1ST THROUGH OCTOBER 31ST.

EACH DAY OF AIR QUALITY AWARENESS WEEK WILL FEATURE A UNIQUE TOPIC RELEVANT TO EDUCATION AND PREPAREDNESS. TODAY WE HIGHLIGHT TWO TYPES OF AIR POLLUTION: OZONE AND PARTICLE POLLUTION...THESE ARE TWO COMMON POLLUTANTS FOUND IN MANY PARTS OF THE COUNTRY.

OZONE IS A COLORLESS ODORLESS GAS. IT IS THE SAME GAS THAT IS FOUND IN THE OZONE LAYER...HIGH IN THE EARTH'S STRATOSPHERE...WHERE IT PROTECTS US FROM THE SUN'S ULTRAVIOLET ENERGY. BUT AT GROUND LEVEL WHERE WE LIVE...OZONE POLLUTION IS UNHEALTHY TO BREATHE. OZONE POLLUTION CAN REACH UNHEALTHFUL LEVELS DURING THE SUMMER AND EARLY FALL MONTHS ACROSS THE MID SOUTH.

PARTICLE POLLUTION...OR AIRBORNE PARTICULATE MATTER...CONSISTS OF MICROSCOPIC PARTICLES IN THE AIR. IN THE MID SOUTH...PARTICULATE MATTER POLLUTION CAN OCCUR YEAR ROUND. LIKE OZONE...PARTICLE POLLUTION IS NOT HEALTHY TO BREATHE. THE PARTICLES ALSO CONTRIBUTE TO HAZE WHICH BLURS THE VIEW IN MANY CITIES AND NATIONAL PARKS.

TOMORROW WE WILL LEARN HOW THESE POLLUTANTS FORM AND CREATE POOR AIR QUALITY CONDITIONS.

FOR MORE INFORMATION ON AIR QUALITY AWARENESS WEEK...VISIT THE WORLD WIDE WEB AT http://www.airquality.noaa.gov

... courtesy NWS/Memphis

The wet pattern returns

What a great few days it's been - spring has definitely arrived! In fact, it was actually pretty warm yesterday with highs eclipsing the 80-degree mark area-wide. Another warm day is expected today with mild nights meaning the Bermuda will be greening up quickly here in the next week. In case you don't know what is "normal" anymore, the average high for this time of year is 74, while the average low is 53. We're running about 10 degrees above that right now!

Unfortunately for those wanting more time to dry out, an unsettled pattern will be setting up for the next several days as a frontal system nears the Mid-South today and stalls jsut northwest of the region through Friday before moving over us Friday night. This will mean on and off chances of showers and t'storms, with the best chances right now appearing to be Thursday and Friday, as well as with the frontal passage Friday night. Following quickly on its heels, another front looks to be moving in late Sunday or Monday, but computer models are really all over the place on timing and location of systems by this weekend, so confidence is still fairly low that far out. I guess we just plan on wet and warm for the next several days!

Freeze Warning tonight

As an upper-level trough maintains its grip on the Mid-South for another 24 hours before moving east, more unseasonably cold weather is on tap for today (lower 50s) with a very cold night expected tonight. The NWS has issued a Freeze Warning for the entire region for tonight as temps are expected to dip below freezing for everyone except those in the heart of the city. While the low at the airport (the official recording station for Memphis) will be around 36, outlying areas will see the mercury drop to 32 by about 2am with a low around 30 (perhaps a degree or two cooler in rural areas) at sunrise. By 9am, everyone should be back above freezing and rising quickly towards a high in the mid 60s. I do expect this to be the last freeze of the spring.

Due to recent warmth, and plenty of rain, many spring plants and flowers have already begun sprouting, growing, and blooming. A few hours of sub-freezing temperatures could damage or kill tender vegetation, especially those not right at the soil level, where soil warmth will protect the lowest couple of inches above the ground. Be sure to cover anything that you do not want damaged overnight tonight. My just-blooming azaleas will definitely be shrouded!

Severe weather behind, but now the cold air sets in

When you step outside over the next few days, you'll probably have to think hard to know what month it is! In the wake of a strong cold front that brought severe weather to many regions of the central and eastern U.S., a huge dome of unseasonably cold air will be settling over the Mid-South beginning today. You'll know it's there because when you look up, you'll find mostly cloudy skies. You'll also know by the cold breezes and temperatures in the 50s instead of the normal 70s! This is all thanks to a massive upper-level trough (or low pressure) that will settle east of the Mississippi River. Some areas north of us will even see snow flurries or showers, but don't count on that here. Instead, look for high temps in the 50s (low 50s Sunday) and lows in the 30s, with a chance of a light rain shower Sunday.

For those of you concerned about spring vegetation that has already made it's appearance, the frost factor for tonight will be minimal thanks to cloud cover and a steady breeze that should keep everyone in the upper 30s. By Sunday night/Monday morning, outlying areas could see a light frost as temps drop into the mid 30s, though once again cloud cover and wind should keep frost to a minimum. The best time to cover those tender outdoor plants will be Monday night. The low Tuesday morning could drop to 28-32 degrees outside the city proper and with clear skies and light wind, frost and perhaps even a couple hours of sub-freezing temps are possible.

The good news is a quick warm-up will take place starting Tuesday and we're back in the 70s Wednesday. I firmly believe that after Tuesday morning, this is the last time we will have to deal with frost until fall!

Severe weather later today

The Mid-South continues to be in a MODERATE risk for severe weather for this afternoon and evening. In addition, a Flash Flood Watch and Wind Advisory are in effect as rain could come quickly with this system, posing a flash flood threat, and windy conditions will prevail all day and tonight with gusts over 40 mph possible.

Here's what the NWS-Memphis office has to say:

SPECIAL WEATHER STATEMENT...UPDATED
NATIONAL WEATHER SERVICE MEMPHIS TN
554 AM CDT THU APR 10 2008

...A SIGNIFICANT SEVERE WEATHER OUTBREAK IS LIKELY ACROSS PORTIONS OF THE MID SOUTH THIS AFTERNOON INTO TONIGHT...

A POWERFUL STORM SYSTEM WILL MOVE EAST INTO THE MID SOUTH LATER TODAY AND TONIGHT. A LINE OF SEVERE THUNDERSTORMS HAS ALREADY DEVELOPED IN ADVANCE OF THIS SYSTEM ACROSS THE SOUTHERN PLAINS EARLY THIS MORNING AND WILL CONTINUE TO MOVE EAST AND INTENSIFY THROUGH THE DAY. BY LATER THIS AFTERNOON...SURFACE HEATING WILL ALLOW THE AIRMASS OVER MUCH OF THE MID SOUTH TO BECOME MODERATELY UNSTABLE. AS LARGE SCALE LIFT OVERSPREADS THE HIGHLY SHEARED AND UNSTABLE AIRMASS IN PLACE...EXPECT THE POSSIBILITY OF DISCRETE THUNDERSTORM DEVELOPMENT AHEAD OF THE APPROACHING LINE OF THUNDERSTORMS. ANY DISCRETE STORMS THAT CAN DEVELOP WILL BECOME SEVERE QUICKLY AND BE CAPABLE OF DAMAGING WINDS...LARGE HAIL...AND TORNADOES. A FEW STRONG TORNADOES WILL BE POSSIBLE WITH ANY DISCRETE STORMS.

THE LINE OF SEVERE THUNDERSTORMS WILL EVENTUALLY MOVE ACROSS THE MID SOUTH LATER THIS EVENING AND OVERNIGHT. THIS LINE OF STORMS WILL LIKELY BE SIGNIFICANT AND CAPABLE OF PRODUCING WIDESPREAD DAMAGING WINDS. WIND GUSTS IN EXCESS OF 80 MPH WILL BE POSSIBLE IN ISOLATED AREAS WHERE SIGNIFICANT BOW ECHOES MOVE THROUGH. LARGE HAIL AND ISOLATED TORNADOES WILL ALSO BE POSSIBLE. THE GREATEST RISK FOR SEVERE WEATHER WILL BE BETWEEN 3 PM CDT AND 11 PM CDT ACROSS FAR WEST TENNESSEE AND NORTHWEST MISSISSIPPI.

Be prepared for the possibility of severe weather later today and tonight - have a plan ahead of time in case severe weather strikes and review severe weather safety tips now.

Severe weather expected Thursday night

A portion of the Severe Weather Outlook from the Memphis office of the NWS...

A POWERFUL STORM SYSTEM IS FORECAST TO MOVE ACROSS THE MID SOUTH THURSDAY AFTERNOON THROUGH FRIDAY MORNING. THE COMBINATION OF STRONG LIFT AND A HIGHLY SHEARED AND UNSTABLE ATMOSPHERE WILL LEAD TO THE DEVELOPMENT OF SEVERE STORMS ACROSS THE WESTERN HALF OF THE REGION THURSDAY AFTERNOON. ANY SEVERE STORMS THAT DEVELOP THURSDAY AFTERNOON WILL BE CAPABLE OF PRODUCING DAMAGING WINDS...LARGE HAIL...AND TORNADOES. A FEW STRONG TORNADOES WILL ALSO BE POSSIBLE OVER THESE AREAS.

THUNDERSTORMS SHOULD EVENTUALLY FORM INTO AN INTENSE SQUALL-LINE AND BRING THE POTENTIAL FOR WIDESPREAD DAMAGING WINDS...LARGE HAIL...AND ISOLATED TORNADOES TO MUCH OF THE MID SOUTH THURSDAY NIGHT INTO FRIDAY MORNING.

In addition, flash flooding will be a concern, and for this reason a Flash Flood Watch will be in effect Thursday night as well. The graphic below (courtesy Storm Prediction Center, NWS) highlights the area where severe weather will be most likely.

Rain continues - but a nice weekend ahead

Greetings! Well, the rain hasn't stopped yet. More is headed our way for a good part of today, but fortunately the thunderstorms should be over with after a LOUD night last night. By this evening, rain will be ending and sunshine is on tap for the weekend! It will take several days to dry out. Unfortunately, the next rain maker is due in by mid-week next week.

My shout out for today goes to the University of Memphis Tigers basketball team down in San Antonio!! If you're headed that way for the weekend, conditions will be dry with highs from 80-85. Nice... Being an alum of the U of M, I'll be rooting hard for a national championship for this very deserving team!

GO TIGERS!!!!