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 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/

The current DAY 1 SLIGHT risk includes 2 HATCHED areas. 
 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: ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/MID-SOUTH…AND PORTIONS OF THE OHIO VALLEY INTO WESTERN PENNSYLVANIA/NEW YORK…

…SPC SUMMARY…
Scattered severe thunderstorms are likely today across parts of Ohio into West Virginia and western Pennsylvania/New York, and from portions of Texas into the lower Mississippi Valley and Mid-South. Damaging winds should be the main threat for most areas, but large hail may occur across parts of Texas, and a few tornadoes appear possible in the upper Ohio Valley.
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. 
CSU – MLP DAY1 PROBABILITY (CLICK FOR LARGER IMAGE)

NSSL ML DAY 1 PROBABILITY

DAY 1 PROBABILITY CONVERSION TABLE

SPC DISCUSSION EXCERPT:
…Ohio Valley into Western Pennsylvania/New York…
The primary surface low is forecast to develop northeastward into Ontario and Quebec through the day, while a trailing cold front moves quickly east-southeastward across the OH Valley and eventually PA/NY. Recent visible satellite imagery shows some clearing across central/eastern OH, and strong low-level warm moist advection associated with a 40-50+ kt low-level jet will aid in a gradual increase in low-level moisture ahead of ongoing convection across KY/southern IL into IN. While MLCAPE should only peak around 500-1000 J/kg ahead of the front by early afternoon, strong flow at low/mid-levels will aid thunderstorm clusters in producing scattered severe/damaging winds as they move quickly eastward across the upper OH Valley later today. The potential for a few line-embedded and/or supercell tornadoes is also apparent given sufficient low-level shear. This convection is forecast to weaken this evening as it moves into the higher terrain of the Appalachians and encounters a much less unstable airmass.

…Texas into the Lower Mississippi Valley/Mid-South…
Current expectations are for an uptick in thunderstorm intensity to occur this afternoon as activity spreads southeastward into a gradually destabilizing airmass across the lower MS Valley/Mid-South. Scattered damaging winds along consolidating outflows should be the main threat for most areas this afternoon through early evening as low-level lapse rates steepen. But, some potential for supercells remains apparent across parts of TX, where steep mid-level lapse rates, greater MUCAPE, and modestly enhanced mid/upper-level flow and related deep-layer shear will support the potential for large hail. Even with the primary upper trough remaining to the north, some enhancement to the low-level winds persists, which may support a brief tornado threat in the short term. See Mesoscale Discussion 164 for more details on the near-term severe threat across AR and vicinity.

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, strong convection was already in progress, and 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  isolated large to severe hail, isolated strong tornadoes (EF2+) which would most likely be within the 5% HATCHED outline in the SPC outline and NADOCAST SIGTOR outline mainly over PA.  Based on indices over TX, AR, and LA., I cannot rule out an isolated strong tornado over that portion of the SLIGHT risk area. 

Based on analysis of model animations, the current outlook, and analysis of indices, the strongest convection and indices could occur approximately between 1:00 P.M. CST MAR. 07 – 6:00 P.M. CST MAR. 07. over the southern risk area, and 2:00 P.M. EST MAR. 07 – 7:00 P.M. EST MAR. 07.  Strongest / Maximum indices based on analysis appear to occur over the 5% SPC HATCHED TORNADO outline over PA. and over a portion of SE TX, and a portion of AR. and LA.  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. Indices on the left are for the southern risk outline, and indices on the right, for the northern risk outline.  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- 3000 j/kg-1……..500- 2000 j/kg-1                 
MLCAPE: 500 – 2000 j/kg-1……..500- 1250 j/kg-1        
MUCAPE: 750 – 3000 j/kg-1……500- 2000 j/kg-1                 
SRH 0 -1 km: 100 – 200 m2/s2….100 – 250 m2/s2             
SRH 0 -3 km: 200 – 300 m2/s2….200 – 400 m2/s2          
SRH EFFECTIVE: 100 – 200 m2/s2….100 – 200 m2/s2            
L. I.: -2 to -8……..-2 to -6                                                    
SCP: 2 – 6……..2 – 5                                          
STP: 0.3 –1.3…….0.4 – 1.1
0 -6 km SHEAR: 40 kts – 60 kts……..40 kts – 50 kts                   
EFF. SHEAR: 30 kts – 50 kts……..30 kts – 40 kts                         
MID LEVEL LAPSE RATE: 6.5C – 8.0C…..6.5C – 7.0C     
DEWPOINT: 60F – 72F……..55F – 63F                                     
EHI: 0.6– 3.1……..0.6 – 3.1                                    
TOTAL TOTALS INDEX: 54C……..50C                  
K INDEX: 28C to 36C……..30C to 34C                                             
SWEAT INDEX: 475 – 535……..435 – 500                         
THOMPSON INDEX: 30 to 44……..32 to 40     
CRAVEN – BROOKS INDEX: 10,000 – 30,000……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 1:00 P.M. EST MAR. 07 – 1:00 A.M. EDT MAR. 08

NAM 3KM STP FORECAST 1:00 P.M. EST MAR. 07 – 1:00 A.M. EDT MAR. 08

NAM 3KM RADAR SIMULATION 1:00 P.M. EST MAR. 07 – 1:00 A.M. EDT MAR. 08

NAM 3KM SCP FORECAST 1:00 P.M. CST MAR. 07 – 9:00 P.M. CST MAR. 07

NAM 3KM STP FORECAST 1:00 P.M. CST MAR. 07 – 9:00 P.M. CST MAR. 07

NAM 3KM RADAR SIMULATION 1:00 P.M. CST MAR. 07 – 9:00 P.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