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 office is closed on Sunday

The Storm Prediction Center (SPC) has issued a MARGINAL risk for severe thunderstorms in the current DAY 1 Outlook: ACROSS PARTS OF THE SOUTHERN APPALACHIANS/SOUTHEAST…

Given the risk increases to SLIGHT for tomorrow, this synopsis will focus on it since the office is closed tomorrow

…SPC SUMMARY DAY 1…
Isolated strong to severe thunderstorms may produce marginally severe hail and damaging winds this afternoon and evening across parts of the southern Appalachians/Southeast.

Please click on the following map for the DAY 1 outlook text
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.

The Storm Prediction Center (SPC) has issued a SLIGHT risk for severe thunderstorms in the current DAY 2 Outlook: ACROSS PARTS OF THE OHIO VALLEY…

…SPC SUMMARY DAY 2…
Severe thunderstorms with large hail and severe wind gusts are expected on Sunday afternoon and evening across parts of the Ohio Valley.

SPC DAY 2 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.
The following is the current CSU – MLP severe weather forecast map and NSSL ML probability forecast:
CSU – MLP DAY 2 FORECAST (CLICK FOR LARGER IMAGE)

NSSL ML DAY 2 SEVERE PROBABILITY 

DAY 2 PROBABILITY CONVERSION TABLE

SPC DISCUSSION EXCERPT DAY 2:
…Ohio Valley/Mid Mississippi Valley…
At mid-levels on Sunday, an amplifying trough will move quickly east-southeastward across the north-central U.S, as an associated jet streak translates eastward into the southern Great Lakes. At the surface, a cold front will advance southward into the Ohio Valley. South of the front, moderate instability will develop across a moist airmass by early afternoon, with surface dewpoints in the lower to mid 60s F. Warming surface temperatures and increasing low-level convergence will result in convective initiation along parts of the front during the mid to late afternoon. Storm coverage is forecast to gradually increase as several clusters or line segments with a severe threat move southeastward across the Ohio Valley during the late afternoon and early evening.

During the afternoon from Cincinnati to Pittsburgh, forecast soundings gradually increase MLCAPE in the 1500 to 2000 J/kg range. Forecasts just ahead of the front suggest that winds will be veered to the southwest near the surface, but that strong speed shear will exist in the lower to mid-levels. 0-6 km shear is forecast to range from 40 to 50 knots, which should be favorable for severe thunderstorm development. 700-500 mb lapse rates in the 7.0 to 7.5 C/km range should support supercells with large hail. The supercell threat is expected to be greatest early in the event, when cells are more likely to be discrete. A threat for severe wind gusts is also expected. The wind-damage threat should be concentrated along short line segments that form in the late afternoon and early evening. A marginal tornado threat will also be possible.

NADOCAST maps will not be available until the SPC DAY 1 outlook.  

Based on my analysis of the preliminary severe weather indices, the forecast calls for a moderately unstable atmosphere at the moment.  Indices and current outlook maps indicate ALL severe weather threats are possible.  Large hail is in the forecast, and should be located mainly within the current 15% HAIL outline.  Based on analysis of strong deep layer shear, 0 – 3km SRH, and EHI values, tornadoes will be possible and should remain within the weaker range of EF0 – EF1.  Although the MAXIMUM SRH value is borderline for an isolated EF2, I am not currently expecting this, unless CAPE, BULK SHEAR, and EHI values increase tomorrow.  However, based on analysis of all indices, I would not rule out a smaller 5% TORNADO outline inside the 2% TORNADO outline.  Currently, strongest severe weather indices should be within the SLIGHT risk, 2% TORNADO outline, and darkest area of the NSSL ML probability outlines.  Some indices will most likely change between issuance of this synopsis, and by the onset of the DAY1 outlook, so this forecast should not be taken as absolute.  
CAPE VALUES FORECAST

DEW POINT FORECAST

Based on analysis of model animations, the current outlook, and analysis of indices, the strongest convection and indices should occur by early afternoon on Sunday, through early evening with current animations indicating the strongest between 3:00 P.M. – 9:00 P.M. EDT.  

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

The following were the forecast parameters and indices analyzed this morning.  Bear in mind, 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: 1000 – 2500 j/kg-1                  
MLCAPE: 500 – 2000 j/kg-1                   
MUCAPE: 1500 – 2500 j/kg-1                
SRH 0 -1 km: 100 – 200 m2/s2               
SRH 0 -3 km: 150 – 250 m2/s2        
SRH EFFECTIVE: 100 – 200 m2/s2          
L. I.: -2 to -9                                                   
SCP: 9 – 13                                             
STP: 1.6 – 2.1 
0 -6 km SHEAR: 40 kts – 50 kts                  
EFF. SHEAR: 30 kts – 40 kts                        
MID LEVEL LAPSE RATE: 7.0C – 8.0C   
DEWPOINT: 60F – 66F                                    
EHI: 0.5 – 3.0                                         
TOTAL TOTALS INDEX: 53C                       
K INDEX: 20C – 28C                                          
SWEAT INDEX: 390 – 425                             
THOMPSON INDEX: 22 – 37                     
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 1:00 P.M. EDT MAR. 22 – 3:00 A.M. EDT MAR. 23

NAM 3KM STP FORECAST 1:00 P.M. EDT MAR. 22 – 3:00 A.M. EDT MAR. 23

NAM 3KM FORECAST RADAR ANIMATION 1:00 P.M. EDT MAR. 22 – 3:00 A.M. EDT MAR. 23

I have provided the SPC homepage link below, so you may get the updated information regarding any changes to the outlook:
SPC HOMEPAGE
https://www.spc.noaa.gov/classic.html

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 any forecasts, 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: twalsh22000@yahoo.com

Have a blessed day!

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