March 19 All Day Severe Weather Situation #008 Update #1

URGENT - IMMEDIATE BROADCAST REQUESTED    SEVERE THUNDERSTORM WATCH NUMBER 51    NWS STORM PREDICTION CENTER NORMAN OK    945 AM CDT SAT MAR 19 2011        THE NWS STORM PREDICTION CENTER HAS ISSUED A    SEVERE THUNDERSTORM WATCH FOR PORTIONS OF                SOUTH CENTRAL AND SOUTHEAST KANSAS           EXTREME WESTERN MISSOURI           NORTHERN OKLAHOMA        EFFECTIVE THIS SATURDAY MORNING AND AFTERNOON FROM 945 AM UNTIL    400 PM CDT.        HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70    MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.        THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 85    STATUTE MILES NORTH AND SOUTH OF A LINE FROM 55 MILES WEST    SOUTHWEST OF WICHITA KANSAS TO 25 MILES EAST NORTHEAST OF JOPLIN    MISSOURI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE    ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).        REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE    FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH    AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR    THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS    AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY    DO PRODUCE TORNADOES.        DISCUSSION...THUNDERSTORMS HAVE BEEN INCREASING IN COVERAGE AND    INTENSITY OVER NORTHERN OK/SOUTHERN KS THIS MORNING AS A SHORTWAVE    TROUGH OVER CO/NM APPROACHES.  STEEP MID LEVEL LAPSE RATES AND    SUFFICIENT ELEVATED CAPE WILL PROMOTE A RISK OF HAIL IN STRONGER    CELLS THROUGH MID AFTERNOON.

March 19 All Day Severe Weather Situation #008

This is a follow-up to the Severe Weather Situation #007.

Above is the SPC radar return with risk areas.

Radar returns indicate the strongest storms may be developing at this time. Pop-up Storms are developing in Oklahoma and Kansas. I do feel the slight risk area will need to be expanded north to account for those pop-up storms.

12z RUC indicates moderate instability by Best Lifted Index in east Oklahoma into extreme southern portions of Kansas.

Most Unstable CAPE values are around 1000 j/kg in the designated areas, indicating an atmosphere that is still in some control of itself.

Will monitor this situation and issue more follow-ups if necessary.

UPDATE 9:51AM CDT

A severe thunderstorm watch has been issued for the area in the above image in blue.

March 19 Severe Weather Forecast Discussion

This is an image of the 4-8 day probability for severe weather.

FORECAST DISCUSSION

The image above is the risk for severe weather 30% or above in the next 4-8 days. When you get a 30% risk, you begin to get into some hot water in the weather world. 30% basically means severe weather will happen and it could happen with strength.

Day 4 (D4), we see a risk area over the Plains into the Midwest. It is shaped in the form a bow echo storm would usually have.

That said, The Weather Centre is definitely eyeing the possibility of a bow echo storm. Should a bow echo develop, it would have potential to cause damaging winds.

The 6z GFS is even pointing at the prospect for a squall line after reviewing the Best Lifted Index images. However, there will be the Canadian air mass that will fight quite hard to keep the severe weather away from the Great Lakes and Ohio Valley. However, that air mass suddenly retreats, leaving the door open for the squall line to come through. However, it does weaken as it comes through, which many of the models have shown.

In Day 5, that squall line suddenly gets a second wind and fires up with more instability in the Ohio Valley. I am unsure of what type of storm it will be, but likely not a squall line or a bow echo. I would anticipate pop-up storms, possibly coming together to form a multi-cell storm complex.

Severe Weather Situation #007

This is Severe Weather Situation #007.

Severe Thunderstorms are forecast to occur this morning into this afternoon in the Oklahoma area.

At 8:09pm CDT... Radar detected thunderstorms developing in the Oklahoma Panhandle. The Weather Centre also indicated high Lifted Index values of -8 in a portion of Oklahoma (The 2nd image down).

A slight risk area has been warranted in the Oklahoma area due to the risk of these storms encountering this unstable atmosphere (First image).

Specific Concerns...

These storms are pop-up storms and will be hard to predict. However, unless you live in the area in the 2nd image down where the -8 circle is, you should be safe. But do keep an eye to the sky if you live in the -6 range.

March 19 9z RUC Best Lifted Index Forecast Discussion

This is an image of right now from the 9z RUC model.

FORECAST DISCUSSION

Weak area of moderate instability in Central Oklahoma providing breeding ground for strong to severe thunderstorms this morning into the afternoon.

At this time, thunderstorms have developed in West Oklahoma and are now moving east into Central Oklahoma.

Will definitely have to monitor the situation for several factors.

One is the image above of the Lifted Index. With values in the -8 range, the atmosphere is at least moderately unstable.

Another factor is Lapse Rate values. Right now at the time of this issuance, Lapse Rates were in the 8-8.5 region in Oklahoma. This provides more evidence of an unstable atmosphere.

This will be a situation to watch, and a Severe Weather Situation will be issued next.