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 a MARGINAL risk for severe thunderstorms for today’s outlook.  The current extended forecast has been reduced  The CSU – MLP and NSSL ML forecast maps have done a decent job in indicating severe weather risks for these days.  One particular note is, the SPC has upgraded the risk for DAY 4 to a probable ENHANCED severe risk, as delineated by the 30% outline. The risk for days 2 and 3 are still at SLIGHT
STORM PREDICTION CENTER (SPC) DAY 4  SEVERE WEATHER OUTLOOK (LINKED)
…DISCUSSION…
…Friday/Day 4…
A strong upper-level system is forecast to eject northeastward into the central High Plains on Friday, as an associated 60 to 80 knot mid-level jet translates northeastward ahead of the trough. At the surface, a moist and unstable airmass will likely be in place from central and east Texas northward into the lower Missouri Valley. Warming surface temperatures and increasing low-level convergence will support scattered convective initiation to the west of the moist axis. Storms are expected to grow upscale in the mid to late afternoon, moving eastward toward an axis of strong low-level flow. Moderate instability, strong deep-layer shear and steep lapse rates will be favorable for supercells. Supercells should be capable of producing tornadoes, large hail and severe wind gusts. The greatest potential is forecast from near the Red River in north Texas north-northeastward across eastern Oklahoma into eastern Kansas and northwestern Missouri, where a 30 percent contour has been added. A severe threat is also forecast northeastward into parts of the mid to upper Mississippi Valley, where strong deep-layer shear and sufficient low-level moisture will be in place for a severe threat.
SPC DAY 2 AND DAY 3 SLIGHT RISK OUTLINES (LINKED)


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

CURRENT DAY1 SEVERE WEATHER OUTLOOK
The Storm Prediction Center (SPC) has issued a MARGINAL risk for severe thunderstorms in the current DAY1 Outlook: ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS INTO MISSOURI AND WESTERN ILLINOIS…

…SPC SUMMARY…
Isolated severe hail may occur this evening into the overnight hours across parts of the southern/central Plains into Missouri and western Illinois.
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.
CSU – MLP DAY1 PROBABILITY (CLICK FOR LARGER IMAGE)

NSSL ML DAY 1 PROBABILITY

DAY 1 PROBABILITY CONVERSION TABLE

SPC DISCUSSION EXCERPT:
…Southern/Central Plains into Missouri and Western Illinois…
A belt of 45-55 kt mid-level southwesterly flow will be maintained today across parts of the southern/central Plains as a shortwave trough ejects eastward over this region though the period. A weak surface low over northeast NM and the OK/TX Panhandles this morning will gradually develop towards northwest TX by this evening as low-level moisture streams northward across TX/OK into the Ozarks and southern IL. A dryline is forecast to mix eastward across the southern High Plains by late this afternoon, intersecting the surface front in the northwest TX/southwest OK vicinity.

Current expectations are for robust thunderstorm development to be suppressed across the southern/central Plains through much of the afternoon into early evening owing to the presence of a stout low-level inversion. One exception may be near the front/dryline intersection in southwest to central OK, where MLCIN should become minimal by peak afternoon heating. Here, some guidance suggests a low chance for a robust thunderstorm or two to develop and track northeastward along/near the I-44 corridor while posing an isolated hail threat. The Marginal Risk has been expanded slightly southward to account for this possibility. Otherwise, gradually increasing large-scale ascent preceding the shortwave trough and strengthening low-level warm/moist advection should encourage the development of elevated thunderstorms north of the front, mainly after 04/06Z. Around 1000-1500 J/kg of MUCAPE, steepened mid-level lapse rates, and strong effective bulk shear suggest that some of these cells may pose a threat for isolated severe hail as they spread from OK/KS into MO and western IL through early Wednesday morning.

The following maps are from NADOCAST for tornado and hail probabilities.  Click images for larger view.  
12Z NADOCAST TORNADO PROBABILITY (CLICK FOR LARGER IMAGE)

12Z NADOCAST SIGTOR PROBABILITY (CLICK FOR LARGER IMAGE)

12Z NADOCAST HAIL PROBABILITY (CLICK FOR LARGER IMAGE)

12Z NADOCAST SIGHAIL PROBABILITY (CLICK FOR LARGER IMAGE)

Based on my analysis this morning of the current severe weather indices, 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 late afternoon through the overnight and early morning hours on Wed.  The main severe risk as of analysis this morning appears to be large hail, with the isolated probability for severe hail, based on lifted indices, bulk shear and, steep mid level lapse rates, and SBCAPE values within the 5% HAIL outline. However, based on analysis at the moment, forecast maps tend to indicate the strongest of indices and parameters will be confined to the Oklahoma portion of the MARGINAL risk and 5% HAIL outlines.  While the strongest / maximum 0 – 3 SRH values (350) are located over the Nebraska portion of the outline, the lack of any MLCAPE in the forecast would pretty much preclude any EHI values and tornado risk.  Should an isolated threat of a tornado materialize, the occurrence would most likely be closer to the center of the state, or within the NADOCAST SIGHAIL outline.  Currently, I am not expecting any tornado activity.  The forecast indices posted below are located over the Oklahoma portion of the outlines (except for SRH of 350).

During the early morning hours approximately around midnight or shortly after, based on the steep lapse rates analyzed, and a focus of MUCAPE around 1000 – 1500, isolated severe hail could spread to eastern Kansas and into Missouri.

Based on analysis of model animations, the current outlook, and analysis of indices, the strongest convection and indices should occur approximately between 4:00 P.M. CST – 8:00 P.M. CST, and possibly isolated strong cells by MIDNIGHT CST over a portion of KS. into MO.  Storms could initiate by 3:00 P.M CST.  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 – 2000 j/kg-1                  
MLCAPE: 250 – 1250 j/kg-1                   
MUCAPE: 500 – 1500 j/kg-1                
SRH 0 -1 km: 50 – 250 m2/s2               
SRH 0 -3 km: 150 – 350 m2/s2        
SRH EFFECTIVE: 50 – 100 m2/s2          
L. I.: -1 to -6                                                  
SCP: 0.0 – 5.0                                          
STP: 0.0 – 0.4
0 -6 km SHEAR: 50 kts – 60 kts                  
EFF. SHEAR: 30 kts – 40 kts                        
MID LEVEL LAPSE RATE: 8.0C – 8.5C   
DEWPOINT: 50F – 64F                                    
EHI: 0.2 – 1.6                                   
TOTAL TOTALS INDEX: 50C                  
K INDEX: 14C to 34C                                          
SWEAT INDEX: 375 – 400                         
THOMPSON INDEX: 15 to 40      
CRAVEN – BROOKS INDEX: 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 3:00 P.M. CST MAR. 03 – 3:00 A.M. CST MAR. 04

NAM 3KM STP FORECAST 3:00 P.M. CST MAR. 03 – 3:00 A.M. CST MAR. 04

NAM 3KM RADAR SIMULATION 3:00 P.M. CST MAR. 03 – 3:00 A.M. CST MAR. 04

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)

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