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.

In order to expedite the forecast issuance, I may have to go with the SPC 1300Z  outlook maps vice the 1630Z maps, as the 1630Z maps do not update until 12:30+ P.M. EDT.  IF this occurs, please visit the SPC site for updated maps.

As of this morning, the Storm Prediction Center has issued a SLIGHT risk for severe thunderstorms for today’s outlook.  To view risks for the remainder of the week, please visit the SPC homepage:
https://www.spc.noaa.gov/
 CSU – MLP 6 PANEL PROBABILITIES (CLICK FOR LARGER IMAGE)

CURRENT DAY1 SEVERE WEATHER OUTLOOK
The Storm Prediction Center (SPC) has issued a SLIGHT risk for severe thunderstorms in the current DAY1 Outlook: THIS AFTERNOON/EVENING FROM ARKANSAS TO NORTHWEST GEORGIA…

…SPC SUMMARY…
Large hail, damaging winds and a couple of tornadoes are possible this afternoon/evening from the Mid-South into northwest Georgia.
SPC DAY 1 1630Z 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. 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. 
CSU – MLP DAY1 PROBABILITY (CLICK FOR LARGER IMAGE)

NSSL ML DAY 1 PROBABILITY

DAY 1 PROBABILITY CONVERSION TABLE

SPC DISCUSSION EXCERPT:
…AR to north GA this afternoon/evening…
A weak mid-upper speed max is cresting the larger-scale ridge and will move from AR to the TN Valley this afternoon/evening. Associated/ongoing convection across AR will likely persist through the afternoon with some tendency for upscale growth, while spreading eastward along the northern gradient of boundary-layer dewpoints in the low-mid 60s. Surface heating in cloud breaks, beneath the eastern extent of 7-8 C/km midlevel lapse rates, will contribute to moderate buoyancy (MLCAPE of 1000-1500 J/kg) along this corridor with minimal convective inhibition.

Deep-layer vertical shear will be sufficient for a somewhat organized/bowing storm cluster to evolve from the ongoing AR storms as they spread across the TN Valley this afternoon, potentially reaching northwest GA by late evening. The initial storms in the cluster will pose a threat for large hail (1-2″diameter), with some increase in the threat for wind damage from northern MS across northern AL/northwest GA. More discrete storms will be possible immediately south of the MCS path this afternoon/evening as a maritime tropical air mass (68-72 F dewpoints) spreads inland. Wind profiles will support supercells capable of producing large hail (some could exceed 2 inches in diameter). A modest increase in low-level shear this afternoon, combined with rich low-level moisture and the possibility of lingering convective outflow from the ongoing storms in AR will also support the potential for a couple of tornadoes.

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 and radar,  strong convection was already in progress, and the forecast seems t0 call for a moderately unstable atmosphere at the moment.  Indices and current SPC outlook indicate severe thunderstorms may be possible from mid afternoon through late evening.  ALL severe risks are probable including  large to very large hail,  and tornadoes (EF0 – EF1) which would most likely be within the 2% – 5% TORNADO outline over MS., and AL., based on indices and current NADOCAST tornado probability map

Based on analysis of model animations, the current outlook, and analysis of indices, the strongest convection and indices could occur approximately between 4:00 P.M. CDT MAR. 09 – MIDNIGHT CDT MAR. 10, over the SLIGHT risk area.  Strongest / Maximum indices based on analysis appear to occur over the 5% – 15% SPC HATCHED SIGHAIL 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.  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: 1500- 2000 j/kg-1  
MLCAPE: 1000 – 1500 j/kg-1      
MUCAPE: 1500 – 2000 j/kg-1           
SRH 0 -1 km: 100 – 200 m2/s2             
SRH 0 -3 km: 150 – 300 m2/s2        
SRH EFFECTIVE: 100 – 200 m2/s2            
L. I.: -4 to -6                                                 
SCP: 2 – 6                                      
STP: 0.4 –1.6
0 -6 km SHEAR: 40 kts – 50 kts                  
EFF. SHEAR: 30 kts – 50 kts                        
MID LEVEL LAPSE RATE: 7.0C – 8.0C    
DEWPOINT: 64F – 72F                               
EHI: 1.0– 2.8                           
TOTAL TOTALS INDEX: 53C                
K INDEX: 28C to 36C                                       
SWEAT INDEX: 425 – 465                    
THOMPSON INDEX: 32 to 42  
CRAVEN – BROOKS INDEX: 10,000 – 30,000        

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 2:00 P.M. CDT MAR. 09 – 4:00 A.M. CDT MAR. 10

NAM 3KM STP FORECAST 2:00 P.M. CDT MAR. 09 – 4:00 A.M. CDT MAR. 10

NAM 3KM RADAR SIMULATION 2:00 P.M. CDT MAR. 09 – 4:00 A.M. CDT MAR. 10

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