Disclaimer:  This site is not affiliated with the National Hurricane Center, Hurricane Hunters, Storm Prediction Center, or National Weather Service.  ALL forecasts herein are the result of my analysis, (to which you will see me at times, insert excerpts from various agencies due to the nature of the importance of the information) and I am solely responsible for the content.  As ALWAYS, follow the National Hurricane Center, National Weather Service, and your local Emergency Management officials for emergency decisions.  In addition, this is strictly a FORECAST OFFICE.  I CANNOT make decisions regarding travel plans, etc.  My purpose, is to provide you the information, based solely on information I analyze, and the accuracy of the information at hand of the time of analysis, so you may make informed decisions.
(T. F. “Storm” Walsh)

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Good day everyone!
The forecast center is closed on Sunday’s.

As of this morning, the Storm Prediction Center has issued a SLIGHT risk for severe thunderstorms for today’s outlook.  There is a SLIGHT risk issued for DAY 2 (MAR. 05), and an ENHANCED risk issued for DAY  3 (MAR. 06) which may produce significant severe weather.
STORM PREDICTION CENTER (SPC) DAY 2 SEVERE WEATHER OUTLOOK (LINKED)

STORM PREDICTION CENTER (SPC) DAY 3 SEVERE WEATHER OUTLOOK (LINKED)


…DISCUSSION EXCERPT… FRIDAY DAY 3…
…Southern and Central Plains/Lower and Mid Missouri Valley…
A strong upper-level trough will move northeastward across the central High Plains on Friday, as an associated mid-level jet translates northeastward across the central Plains. At the surface, a cold front will advance southeastward across the central Plains and southern High Plains during the afternoon. Ahead of the front, surface dewpoints will be in the lower to mid 60s F. As surface temperatures warm, moderate instability will develop over much of the moist sector by midday. Increasing low-level convergence along the front, and across parts of the moist sector will result in convective initiation during the mid to late afternoon. Scattered thunderstorms are forecast to develop and move east-northeastward toward the instability axis, where strong low-level flow be maximized. This will result in a substantial severe threat from late afternoon into the evening from the southern and central Plains north-northeastward into the lower to mid Missouri Valley.

A well-defined 65 to 85 knot mid-level jet is forecast to move across the southern and central High Plains during the afternoon. This feature will create moderate to strong deep-layer shear over much of the moist sector, which will be favorable for severe storms. Recent runs from the ECMWF have the position of the mid-level jet further south during the late afternoon, which will be more favorably timed for a severe weather event in the southern and central Plains. Several NAM forecast soundings across southern and central Oklahoma northeastward into southeast Kansas by early evening have 0-6 km shear around 50 knots with 0-3 km storm relative helicity in the 300 to 400 m2/s2 range. Low-level shear will be strong due to a focused 850 mb jet forecast to develop over eastern Oklahoma. This will support a threat for supercells with strong tornadoes. In addition to the instability and shear, steep low to mid-level lapse rates will also be in place supporting a large hail and wind-damage threat. Hailstones greater than 2 inches in diameter will be possible with the more intense supercells. The potential for supercells with tornadoes and large to very large hail will extend as far north as the Kansas City Metro, where a secondary low-level jet is forecast to develop early Friday evening. The severe threat should persist from the evening into the overnight period, as multiple supercell clusters gradually congeal into a severe line segment.

CSU – MLP 6 PANEL PROBABILITIES (CLICK FOR LARGER IMAGE)

STORM PREDICTION CENTER (SPC) DAY 7 SEVERE WEATHER OUTLOOK (LINKED)


CURRENT DAY1 SEVERE WEATHER OUTLOOK
The Storm Prediction Center (SPC) has issued a SLIGHT risk for severe thunderstorms in the current DAY1 Outlook: FROM NORTH TEXAS/EASTERN OKLAHOMA TO OZARKS AND LOWER OHIO VALLEY…

…SPC SUMMARY…
Isolated to scattered severe thunderstorms are expected through tonight from north-central Texas and eastern Oklahoma to the Ozarks and Lower Ohio Valley. Large hail, localized wind damage, and a tornado or two are possible.

SPC DAY 1 SEVERE THUNDERSTORM OUTLOOK (LINKED FOR OUTLOOK TEXT)

TORNADO PROBABILITY

Probability of a tornado within 25 miles of a point.
HAIL PROBABILITY

Probability of one inch diameter hail or larger within 25 miles of a point.
DAMAGING THUNDERSTORM WIND PROBABILITY

Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
CSU – MLP DAY1 PROBABILITY (CLICK FOR LARGER IMAGE)

NSSL ML DAY 1 PROBABILITY

DAY 1 PROBABILITY CONVERSION TABLE

SPC DISCUSSION EXCERPT:
Across most of the Slight Risk area, effective bulk shear of 35-50 kt will easily support organized convection regionally, although convective mode may tend to be somewhat messy given broad ascent within the modest low-level warm advection regime near the surface front. Additionally, ongoing mostly elevated convection this morning across northeast Oklahoma into southern Missouri and southern Illinois may hamper stronger heating and limit destabilization downstream, with outflow/existing convection contributing to modal complexity later today.

Even with these potential limitations, a broad area of isolated to scattered severe thunderstorm potential exists through tonight. An isolated and/or occasional hail threat may persist with ongoing elevated convection from southern Missouri into southern Indiana/northern Kentucky. Surface-based thunderstorm development should otherwise become more probable across the Ozarks into mid/late afternoon closer to the surface front/surface low and modifying outflow. A mix of supercells and clusters will pose a risk for large hail. Damaging winds will also be possible where steepened low-level lapse rates can develop with daytime heating. Although low-level flow is not forecast to become overly strong, there should be sufficient 0-1 km SRH to support some threat for a couple of tornadoes with any sustained supercells/clusters, particularly across southern Missouri and northern Arkansas.

The following maps are from NADOCAST for tornado and hail probabilities.  
12Z NADOCAST TORNADO PROBABILITY
12Z NADOCAST SIGTOR PROBABILITY 
12Z NADOCAST HAIL PROBABILITY 

12Z NADOCAST SIGHAIL PROBABILITY 

Based on my analysis this morning of the current severe weather indices, the forecast seems t0 call for a high end moderately unstable atmosphere at the moment.  Indices and current SPC outlook indicate severe thunderstorms may be possible from afternoon through late evening.  The main severe risk as of analysis this morning appears to be large hail, with the probability for  isolated severe hail, based on lifted indices, bulk shear and, steep mid level lapse rates, and SBCAPE values within the 15% HAIL outline, and damaging thunderstorm winds / gusts.  Tornadoes may be likely based on the 2 – 5% TORNADO outline, with the greatest possibility over Arkansas based on the 12Z NADOCAST forecast map.

Based on analysis of model animations, the current outlook, and analysis of indices, the strongest convection and indices should occur approximately between 3:00 P.M. CST – 9:00 P.M. CST.  Strongest indices based on analysis appear to occur over the 2% – 5% NADOCAST tornado area over SE Oklahoma and northern portion of Arkansas. Please visit the SPC homepage via the link provided for any changes to the forecast today.
CAPE VALUES FORECAST

DEW POINT FORECAST

Indices were analyzed from the NAM 3KM, HRRR 3KM, CIPS DETERMINISTIC, and SPC SREF model guidance.

The following were the forecast parameters and indices analyzed this morning.  Bear in mind, MAXIMUM indices recorded below are for the time of peak intensity, and can change between this analysis and the DAY 1 outlook.  Some indices meanings are posted below the indices themselves, and the NWS page containing a more extensive explanation can be accessed further on in the synopsis:
SBCAPE: 750 – 2500 j/kg-1                  
MLCAPE: 500 – 1500 j/kg-1                   
MUCAPE: 750 – 2500 j/kg-1                
SRH 0 -1 km: 100 – 250 m2/s2               
SRH 0 -3 km: 150 – 300 m2/s2        
SRH EFFECTIVE: 100 – 200 m2/s2          
L. I.: -2 to -6                                                  
SCP: 2.0 – 5.0                                          
STP: 0.4 – 1.8
0 -6 km SHEAR: 40 kts – 50 kts                  
EFF. SHEAR: 30 kts – 40 kts                        
MID LEVEL LAPSE RATE: 7.0C – 8.0C   
DEWPOINT: 61F – 69F                                    
EHI: 0.5 – 2.8                                  
TOTAL TOTALS INDEX: 54C – 55C                 
K INDEX: 23C to 34C                                          
SWEAT INDEX: 450 – 525                       
THOMPSON INDEX: 25 to 40      
CRAVEN – BROOKS INDEX: 10,000 – 20,000     

CAPE

ENERGY HELICITY INDEX

K INDEX

TOTAL TOTALS INDEX

STORM RELATIVE HELICITY

LIFTED INDEX

SWEAT VALUES

THOMPSON INDEX

Craven SigSvr Parameter:
The simple product of 100mb MLCAPE and 0-6km magnitude of the vector difference (m/s; often referred to as “deep layer shear”) accounts for the compensation between instability and shear magnitude. Using a database of about 60,000 soundings, the majority of significant severe events (2+ inch hail, 65+ knot winds, F2+ tornadoes) occur when the product exceeds 20,000 m3/s3.

A little fact on SRH values and tornadoes from NOAA / NWS
Storm Relative Helicity (m² s^-2)
SRH (Storm Relative Helicity) is a measure of the potential for cyclonic updraft rotation in right-moving supercells, and is calculated for the lowest 1-km and 3-km layers above ground level. There is no clear threshold value for SRH when forecasting supercells, since the formation of supercells appears to be related more strongly to the deeper layer vertical shear. Larger values of 0-3-km SRH (greater than 250 m² s^-2) and 0-1-km SRH (greater than 100 m² s^-2), however, do suggest an increased threat of tornadoes with supercells. For SRH, larger values are generally better, but there are no clear thresholds between non-tornadic and significant tornadic supercells.

STP ( Significant Tornado Parameter) EXPLAINED:
A majority of significant tornadoes (EF2 or greater damage) have been associated with STP values greater than 1, while most non-tornadic supercells have been associated with values less than 1 in a large sample of RAP analysis proximity soundings.

SCP (Supercell Composite Parameter) EXPLAINED:
A multiple ingredient, composite index that includes effective storm-relative helicity (ESRH, based on Bunkers right supercell motion), most unstable parcel CAPE (muCAPE) and convective inhibition (muCIN), and effective bulk wind difference (EBWD). Each ingredient is normalized to supercell “threshold” values, and larger values of SCP denote greater “overlap” in the three supercell ingredients. Only positive values of SCP are displayed, which correspond to environments favoring right-moving (cyclonic) supercells.

The following are the SCP (Supercell Composite Parameter) and STP (Significant Tornado Parameter) forecast maps from the NAM 3KM model.  Generally, the higher the values and brighter the color, indicates a greater probability of strong thunderstorm and / or tornadic activity over an area:
NAM 3KM SCP FORECAST 12:00 NOON CST MAR. 04 – 3:00 A.M. CST MAR. 05

NAM 3KM STP FORECAST 12:00 NOON CST MAR. 04 – 3:00 A.M. CST MAR. 05

NAM 3KM RADAR SIMULATION 12:00 NOON CST MAR. 04 – 3:00 A.M. CST MAR. 05

Please use the following maps, which should update automatically, for Mesoscale Discussions and Convective Watches.  You may have to refresh your browser, or click on the graphics.  I have provided the SPC homepage link below, so you may get the updated information regarding any changes to the outlook:
https://www.spc.noaa.gov/classic.html
SPC MESOSCALE DISCUSSIONS (CLICK IMAGE FOR UPDATES)

SPC CONVECTIVE WATCHES (CLICK IMAGE FOR UPDATES)

The following sites will explain most of the severe weather and tornado values listed above, and will give you an idea of what to expect:
ENVIRONMENTAL INDICES AND PARAMETERS NWS
https://www.weather.gov/lmk/indices

THE WEATHER PREDICTION
http://www.theweatherprediction.com/severe/indices/

The following links will connect you to the Excessive Rainfall probabilities and River Flood Outlook:
EXCESSIVE RAINFALL
https://www.wpc.ncep.noaa.gov/qpf/excessive_rainfall_outlook_ero.php

SIGNIFICANT RIVER FLOOD OUTLOOK
https://www.wpc.ncep.noaa.gov/nationalfloodoutlook/index.html

The following NWS Watch / Warning map will provide local NWS information for your area.  Click the image, then once it refreshes, click on your area of interest to view forecasts, any special weather statements, hazards or advisories for your area.
IF A TORNADO WARNING IS ISSUED FOR YOUR AREA…SEEK STURDY AND SAFE SHELTER IMMEDIATELY!

NWS WATCH / WARNING DISPLAY (LINKED…CLICK MAP, THEN YOUR AREA)

NWS DOPPLER RADAR LOOP (LINKED, CLICK RADAR MAP)

RAP RADAR (CLICK IMAGE THEN GO TO LOOP DURATION AND PICK LENGTH OF LOOP, THEN CLICK RADAR SITE)
WUNDERGROUND RADAR SUMMARY MAP (CLICK FOR UPDATES)

PRECIPITATION TYPE (CLICK TO ACCESS ANIMATION FEATURE)

CARIBBEAN RADAR (CLICK IMAGE TO ACCESS ANIMATION)

You may direct any questions by contacting me personally, ANYTIME, at: twalsh22000@yahoo.com

Have a blessed day!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST