Possible severe weather for Mid-South today

Yesterday, parts of the area got a taste of how tropical remnants can produce severe weather, particularly tornadoes. As was the case yesterday afternoon near Oxford, MS, these funnels and tornadoes are usually weak, however they are still tornadoes and can still do damage. They also don't get produced from the same types of tornadic storms we are more familiar with in these parts - those of the supercell or squall line variety. While supercells may have storm tops that extend to 40-50,000 feet plus, tropical remnants are more low-topped (25,000 feet or so), but due to the strong to extreme wind shear that exists in these systems, funnels and weak tornadoes are easier to come by.

Today, we are under a SLIGHT RISK of severe weather with the greatest threat being from weak tornaodes this afternoon and early evening that would might be produced by any stronger showers and t'storms that form in banding structures that rotate around the center of the storm. Continue to keep a weather eye to the sky as the day progresses and visit MemphisWeather.net for the latest on the severe weather threat.

pics from last night's storms

Just before sunset last night (8:00pm CDT), I took the pics below of the underside of the anvil from a cluster of strong/severe t'storms. Storms were located to the south with the anvil extending over my place and the pics were taken looking generally west. The sun striking the underside of the clouds, combined with some mammatus, cirrostratus, and lower altocumulus, created some phenomenal looking sky conditions. It actually came out more yellow in the camera than it looked outside, but still pretty cool pics! I've also included a radar cross-section showing the area of the storm where the pictures were taken - the underside of the anvil. Let me know what you think! (And no, we didn't get any rain.)

In the middle of the storm

Well, the strong storms have made it into the northern suburbs. As I type this, we are under a Severe Thunderstorm Warning and it's "raining cats and dogs." In the past 15 minutes, we have received 2/3 of an inch of rain with rain rates in excess of 4". The peak wind gust from my newly-raised anemometer (now at 16' above ground level) was 30 knots out of the north at 10:55pm. This line should continue moving slowly south and affect the Memphis area for the next hour to hour and a half. A slow dissipation trend is still expected during this time frame. Copious lightning and accompanying thunder is also expected from these storms.

4:25pm - Tornado Watch issued

The Storm Prediction Center has issued Tornado Watch #298 for the entire Mid-South valid until midnight CDT. Storms are expected to start rapidly developing within a couple of hours as the warm front lifts through the metro area. Scattered, strong to severe, discrete cells will be likely for the next 5-6 hours until the main line of storms, likely also severe, passes through between 10pm-1am. The greatest threat of tornadoes will exist within these discrete cells, with damaging wind and hail the main threat with the squall line. See http://www.spc.noaa.gov/products/watch/ww0298.html for more info on the Tornado Watch.

Severe Weather Discussion - 1:00pm Saturday, May 10, 2008

Things are still shaping up for a likely severe weather outbreak later today across the Mid-South. As of 12:30pm, morning clouds are breaking up over the area and temperatures are starting to climb. With enough sunshine, we'll likely reach near 80 degrees this afternoon. In addition, a strong upper-level disturbance is moving through the Plains towards the region and scattered thunderstorms are firing in response to the increased winds and dynamics over western AR and MO and eastern KS and OK (see current regional radar). As the afternoon goes on, these scattered storms will become stronger as they move east. To our south, a warm front is positioned and will begin to surge north this afternoon across the area (see forecast surface maps). As it does so, our wind will turn to a more southerly direction and moisture will increase further. It is near this warm front that storms will have the best chance of becoming super-cellular and capable of producing tornadoes. In addition, any storms that form could contain large hail (1" or larger) and high wind in excess of 60 mph.

During the evening hours, the metro area will be positioned in the warm sector - behind the northbound warm front and ahead of a strong cold front moving in from the Southern Plains. Within the warm sector, storms will continue to be scattered, but very capable of becoming severe. As the cold front moves closer, the likely scenario is that a squall line will form along or just ahead of the front and race across the region overnight. Within the line, the primary threat would be very high wind (75 mph+ possible) and large hail, but isolated tornadoes will continue to also be a threat. The timing of all of this appears to be that the warm front will move through around 5-6pm, so the severe weather threat increases around that time, and the squall line would move through between 11pm and 2am. Thus, severe weather is a distinct possibility from about 5pm until 2am.

Be sure that you take time to review your severe weather safety plan of action. That plan should include staying abreast of changing weather conditions with MemphisWeather.Net, as well as local or cable TV or radio, and preferably a NOAA All-Hazards Alert Radio. You can also sign up to receive email alerts of weather watches and warnings for the Memphis metro area by clicking on "Notification" from the Severe Weather menu on MemphisWeather.Net.

Outbreak of severe weather likely later today

The Storm Prediction Center and NWS-Memphis are forecasting an outbreak of severe weather, including possibly strong long-tracked tornadoes, for the Mid-South late this afternoon through the very early morning hours Sunday. Stay with MemphisWeather.Net and your local network and cable TV outlets for the latest on this developing severe weather scenario.

PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0643 AM CDT SAT MAY 10 2008

...SEVERE THUNDERSTORMS ARE EXPECTED FROM THE ARKLATEX AND MID SOUTH REGION EASTWARD ACROSS THE GULF COAST STATES TODAY AND TONIGHT...

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE DEVELOPMENT OF A FEW STRONG TORNADOES...WIDESPREAD DAMAGING WIND AND VERY LARGE HAIL FROM THE ARKLATEX AND MID SOUTH REGION EASTWARD ACROSS THE GULF COAST STATES TODAY AND TONIGHT.

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE:
CENTRAL AND NORTHERN ALABAMA
MUCH OF ARKANSAS
MUCH OF GEORGIA
FAR SOUTHERN ILLINOIS
FAR WESTERN KENTUCKY
NORTHERN LOUISIANA
SOUTHERN MISSOURI
CENTRAL AND NORTHERN MISSISSIPPI
FAR EASTERN OKLAHOMA
WESTERN AND MIDDLE TENNESSEE
FAR EASTERN TEXAS

A STRONG UPPER LEVEL TROUGH WILL MOVE EASTWARD ACROSS THE PLAINS STATES THIS AFTERNOON...EMERGING INTO THE LOWER MISSISSIPPI VALLEY BY LATE TODAY AND CONTINUING ACROSS THE TENNESSEE VALLEY REGION AND GULF COAST STATES OVERNIGHT INTO SUNDAY MORNING. A VERY MOIST AND UNSTABLE AIR MASS IS ALREADY IN PLACE FROM TEXAS EASTWARD ALONG THE GULF COAST...AND THIS UNSTABLE AIR WILL EXPAND NORTHWARD WITH TIME AS LOW PRESSURE DEEPENS ACROSS THE MID MISSISSIPPI VALLEY. WHILE TORNADOES...DAMAGING WIND AND VERY LARGE HAIL WILL BE POSSIBLE ANYWHERE WITHIN THE MODERATE RISK AREA...THE GREATEST THREAT FOR STRONG TORNADOES WILL OCCUR THIS AFTERNOON AND EVENING OVER CENTRAL AND EASTERN ARKANSAS...NORTHERN MISSISSIPPI AND WESTERN TENNESSEE. IN ADDITION TO THE THREAT OF A FEW TORNADOES...WIDESPREAD DAMAGING WINDS WILL BE POSSIBLE DURING THE EVENING AND OVERNIGHT HOURS ACROSS MISSISSIPPI...ALABAMA...AND GEORGIA.

THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE WEATHER SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA WEATHER RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.

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

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.