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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I will reiterate, my forecasts are based on the available information at the time of analysis, and are only as accurate as the information analyzed and the solutions provided.

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

As of this morning, the Storm Prediction Center has issued an ENHANCED risk for severe thunderstorms for today’s outlook.  There is an SLIGHT risk issued for DAY 2 (MAR. 07), and a probable SLIGHT risk issued for DAY 5 and DAY 6.

The current DAY 1 ENHANCED risk includes HATCHED areas which may produce significant severe weather. 
 

STORM PREDICTION CENTER (SPC) DAY 2 SLIGHT SEVERE WEATHER OUTLOOK (LINKED)

STORM PREDICTION CENTER (SPC) DAY 5 AND DAY 6 SEVERE WEATHER OUTLOOK (LINKED)


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

…SPC SUMMARY…
Scattered severe thunderstorms are expected from mid-afternoon through tonight across parts of the southern/central Plains to the Ozarks and Midwest. The greatest potential for a few strong tornadoes and very large hail should exist across eastern portions of Oklahoma/Kansas/Nebraska into western Arkansas/Missouri and southern Iowa.
SPC DAY 1 SEVERE THUNDERSTORM OUTLOOK (LINKED FOR OUTLOOK TEXT)

TORNADO PROBABILITY

Probability of a tornado within 25 miles of a point.  Hatched Area: 10% or greater probability of EF2 – EF5 tornadoes within 25 miles of a point.
HAIL PROBABILITY

Probability of one inch diameter hail or larger within 25 miles of a point. Hatched Area: a 10% or greater probability of 2-inch diameter or larger hail 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.  Hatched Area: a 10% or greater probability of 65 kt+ winds 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:
…Central Plains and Midwest/Great Lakes…
Low-level moisture will continue to stream northward today ahead of the cold front across east-central Nebraska and western Kansas, with upper 50s to low 60s F surface dewpoints common by mid afternoon. Cold temperatures aloft and steepened mid-level lapse rates will support the development of at least 1000-1500 J/kg of MLCAPE with daytime heating. More instability may exist farther south into Kansas where greater low-level moisture will be in place, although such details are complicated by existing convection/cloud cover across eastern Kansas into northwest Missouri at mid-morning.

This activity will pose a risk for large to very large hail, but fairly quick upscale growth into one or more bowing clusters with a wind damage threat seems probable along/ahead of the cold front as convection spreads into Iowa/Missouri this evening. Some risk for at least isolated severe/damaging winds may persist late tonight into early Saturday morning across Wisconsin/Illinois and Lower Michigan if these clusters can maintain intensity, although instability is forecast to become more limited with eastward extent across these areas.

A few tornadoes may occur with sustained supercells or embedded QLCS circulations across the central Plains/Midwest along/south of the warm front given favorable low-level shear and enlarged/curved hodographs. Pending development into the warm sector, a strong tornado could occur with any supercells this evening as low-level shear strengthens in tandem with a south-southwesterly low-level jet.

…Southern Plains and Ozarks…
Where cells can sustain and mature, they would likely become severe and pose a threat for very large hail given the presence of steep mid-level lapse rates noted on the 12Z OUN observed sounding, along with around 35-45 kt of deep-layer shear aiding updraft organization. The tornado threat would also increase this evening with any persistent supercells as low-level shear gradually strengthens. Additional and more probable robust thunderstorm development remains apparent later this evening/tonight as the cold front accelerates south-southeastward. Both large hail and damaging winds may occur with this overnight activity through the end of the period.

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 moderately unstable to very unstable atmosphere at the moment.  Indices and current SPC outlook indicate severe thunderstorms may be possible from afternoon through late evening into early morning.  ALL severe risks are probable including large to severe hail, including strong tornadoes (EF2+) which would most likely be within the 5% – 10% HATCHED outline in the SPC outline and NADOCAST SIGTOR outline.  Based on the hatched outlines within the risk outlines, ISOLATED SIGNIFICANT severe weather seems probable.  Based on this along with analysis of certain forecast indices, this event could become an isolated PDS (Particularly Dangerous Situation), and could warrant an isolated PDS watch.  If you have one, PLEASE monitor NOAA Weather Radio broadcasts and follow your local NWS office statements.

Based on analysis of model animations, the current outlook, and analysis of indices, the strongest convection and indices could occur approximately between 3:00 P.M. CST MAR. 06 – 10:00 P.M. CST MAR. 06.  Strongest / Maximum indices based on analysis appear to occur over the 5% – 10% NADOCAST and SPC 10% HATCHED TORNADO outline tornado area over SE Oklahoma and the adjacent states in the 10% TORNADO outline.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: 500 – 2500 j/kg-1                  
MLCAPE: 500 – 1500 j/kg-1                   
MUCAPE: 750 – 2500 j/kg-1                
SRH 0 -1 km: 200 – 300 m2/s2               
SRH 0 -3 km: 250 – 400 m2/s2        
SRH EFFECTIVE: 150 – 300 m2/s2          
L. I.: -1 to -9                                                 
SCP: 2 – 12                                        
STP: 0.5 – 3.0
0 -6 km SHEAR: 40 kts – 50 kts                  
EFF. SHEAR: 30 kts – 40 kts                        
MID LEVEL LAPSE RATE: 7.0C – 8.5C   
DEWPOINT: 59F – 68F                                    
EHI: 0.8 – 3.6                                 
TOTAL TOTALS INDEX: 56C             
K INDEX: 28C to 36C                                          
SWEAT INDEX: 515 – 575                       
THOMPSON INDEX: 31 to 45      
CRAVEN – BROOKS INDEX: 10,000 – 40,000     

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 1:00 P.M. CST MAR. 06 – 3:00 A.M. CST MAR. 07

NAM 3KM STP FORECAST 1:00 P.M. CST MAR. 06 – 3:00 A.M. CST MAR. 07

NAM 3KM RADAR SIMULATION 1:00 P.M. CST MAR. 06 – 3:00 A.M. CST MAR. 07

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)

IF A TORNADO WARNING IS ISSUED FOR YOUR AREA…SEEK STURDY AND SAFE SHELTER IMMEDIATELY!

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.
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: [email protected]

Have a blessed day!

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