REGIONAL SEVERE WEATHER OUTBREAK…MODERATE SEVERE THUNDERSTORM RISK FORECAST SYNOPSIS…ISSUED MAR. 30, 2023…9:40 P.M. EDT

Disclaimer:  This 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)

For those who have donated to my site, your help has been greatly appreciated.  If you are not aware, donations to my site help pay for subscriptions to sites I use as well as software updates, which provide all the models and information used in my forecasts.  To donate, please click the DONATE button to the right side of the page, or on the graphic of the dog.  Any help you provide is immensely appreciated!
DONATIONS ACCEPTED AND APPRECIATED

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.

The outlined maps you were used to seeing from my F5 DATA software, are no longer around and operational.  This means I have lost quite a bit of data to analyze but I will try to make the severe weather forecasts as accurate and understandable as possible.

The Storm Prediction Center (SPC), has issued a MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN IOWA INTO NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI…AND ALSO ACROSS NORTHEAST ARKANSAS…THE MISSOURI BOOTHEEL…EXTREME WESTERN KENTUCKY…WESTERN TENNESSEE…AND FAR NORTHWEST MISSISSIPPI…

…SPC SUMMARY…
Intense and widespread severe thunderstorms are expected Friday afternoon into the overnight hours across portions of the Middle Mississippi Valley and Mid-South vicinity, eastward to the Lower Ohio and Tennessee Valleys. Intense, damaging gusts and several tornadoes (some strong and long-track) are expected.

…A regional outbreak of severe storms is expected on Friday across parts of the Mid-Mississippi Valley and also into the Mid-South…
SPC DAY 2 SEVERE THUNDERSTORM OUTLOOK MAPS (this map linked)

TORNADO

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 of one inch diameter hail or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point.
DAMAGING WINDS

Based on my analysis this evening of the SPC DAY 2 Convective Outlook, and severe weather and tornado indices, all severe threats will be probable for tomorrow.  Based on analysis of information in the SPC DAY 2 outlook synopsis, and indices analyzed from the current CIPS model and NAM 18Z run, ALL severe threats will be onboard with a regional outbreak of severe storms over portions of the mid- Mississippi Valley and mid south. Based on animations from the NAM model and SPC SREF, storms should initiate by 1:00 p.m. CDT, and begin strengthening by late afternoon, with the most intense estimated between 4:00 p.m. to 8:00 p.m. CDT, moving into TN after 8:00 p.m., and should gradually weaken overnight.  At the moment (and again, there could be changes between this evening’s analysis, and analysis of morning soundings) there are 2 areas of MODERATE risk, and a large ENHANCED risk area.  Based on analysis, it appears some of the strongest severe indices will be in the northern portion of the ENHANCED outline, and within the northern most MODERATE risk area.  Although some of the indices will tend to bee somewhat weaker in the southern portion and southern MODERATE area, both areas should be susceptible to isolated strong, long tracked tornadoes.  The current outlook maps indicate the current threat probs.  Based on the current indices, the atmosphere is poised to be on the high end of moderately unstable.  A combination of strong low level shear speed and directional shear, along with moderately high SRH indicate the probability for strong storm rotation.  Based on the actual values, I cannot rule out the probability of an isolated EF4 – EF5 tornado in one of the moderate risk areas, or close the the areas within the ENHANCED outline close to the MODERATE outline.  Residents within the MODERATE and ENHANCED risk areas should monitor NOAA Weather Radio closely, along with their local news and NWS office.  You’ll note the strength changes in the NAM SCP and STP animations.  This event has the potential to become a PDS (Particularly Dangerous Situation), and I cannot rule out an isolated PDS Tornado Watch over one of the MODERATE risk areas.

The following forecast indices and parameters were observed in analysis this evening for the risk area.  Depending on how exactly the situation develops, and degree of daytime heating, these values CAN change between now and the 12Z model run:
SBCAPE: 1500 – 2500 j/kg-1
MLCAPE: 1000 – 1500 j/kg-1
MUCAPE: 1500 – 2000 j/kg-1
SRH: 300 – 500 m2/s2
L. I.: -5 to -6
MOST UNSTABLE L. I.: -5 to -7
STP: 2 to 9 north…2 to 7 south
SCP: 4 to 12
EFF. SHEAR: 50 –  70 KTS
MID LEVEL LAPSE RATE: 7.5 – 8.0C
DEWPOINT: 60F – 68F

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 sites will explain most of these values, 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/

Please visit the SPC main site at the following link for tomorrow’s activity:
SPC HOMEPAGE LINK
https://www.spc.noaa.gov/classic.html

The following are animations of both the SCP and STP currently for tonight, however slight changes are possible between now and tomorrows model run.  The animation runs from 1:00 p.m. tomorrow to 1:00 a.m. CDT.  The greater the value, the greater the risk a strong tornado in an area.
NAM MODEL SCP FORECAST

NAM MODEL STP FORECAST

Please visit my site again for the severe event to 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 above, so you may get the updated information regarding any changes to the outlook:
SPC MESOSCALE DISCUSSIONS (CLICK IMAGE FOR UPDATES)

SPC CONVECTIVE WATCHES (CLICK IMAGE FOR UPDATES)

IF A TORNADO WARNING IS ISSUED FOR YOUR AREA, IMMEDIATELY TAKE STURDY AND SAFE SHELTER
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 special weather statements, hazards or advisories for your area.
NWS WATCH / WARNING DISPLAY (LINKED…CLICK MAP, THEN YOUR AREA)

WSI DOPPLER RADAR LOOP (LINKED)

RAP RADAR (CLICK IMAGE THEN GO TO LOOP DURATION AND PICK LENGTH OF LOOP, THEN CLICK RADAR SITE)
You may direct any questions by contacting me personally, ANYTIME, at: twalsh22000@yahoo.com

Have a blessed evening!

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