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)
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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.
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.
I know this synopsis is late, however I wanted to get it out before the very serious weather began.
The Storm Prediction Center (SPC), has issued an MODERATE risk of severe thunderstorms CENTERED ON WESTERN...CENTRAL...AND NORTHERN OKLAHOMA...
...SPC SUMMARY...
A derecho is forecast with widespread damaging winds and embedded swaths of significant severe gusts from 80-110 mph, centered on parts of Oklahoma this evening into tonight. Embedded tornadoes are anticipated as well, with the greatest potential for strong (EF2-EF3) tornadoes across southwest Oklahoma this evening.
SPC DAY 1 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
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% or greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Based on my analysis recently of the current SPC day 1 convective outlook, along with analyzed severe and tornado indices, there are 3 main severe threats looming for this evening. The main threat being damaging straightline and possibly rotating thunderstorm winds, along with very large to severe hail, and a probability of strong tornadoes within the MODERATE and ENHANCED severe risk areas. Recent analysis of the NAM model indicates 700 mb winds of around 90+ kts, and 500 mb winds of possibly 95 - 105 kts. Analysis of the 250 mb map indicated excellent divergence aloft, with the risk areas lying within the left rear entrance region of the jet. This will equate to the forecast damaging surface winds, as well as added lift in the atmosphere. Given the veering of winds from the surface up through 500 mb, and high SRH values, some of the tornado activity could produce some isolated strong tornadoes (EF2+), mainly in the MODERATE and ENHANCED risk areas, given the excellent rotation analyzed along with recent hodograph analysis. Indications are that storms should begin to break out right about now, approximately 3:00 p.m. CST along the dryline, and should begin to organize into supercellular structure near 00Z (6:00 p.m. CST). As convection grows through the evening, it is forecast to consolidate into a QLCS (a solid squall line) and contain both embedded supercells and mesovortices. Based on my analysis of the situation, this may have the potential to become a PDS (Particularly Dangerous Situation) within the MODERATE risk area. I cannot rule out the possibility of at least one PDS tornado watch being issued sometime this evening. Based on analysis of the NAM STP and SCP animation maps, the system may begin to weaken after midnight CST.
NAM 500 MB WIND FORECAST
NAM 700 MB WIND FORECAST
NAM 250 MB WIND FORECAST
The following forecast indices and parameters were observed in analysis this evening for the risk area:
SBCAPE: 1000 – 1500 j/kg-1
MLCAPE: 750 – 1000 j/kg-1
SRH: 500 – 700 m2/s2
L. I.: -1 to -3
MOST UNSTABLE L. I.: -3 to -6
STP: 3 to 9
SCP: 6 to 12
EFF. SHEAR: 50 – 60 KTS
MID LEVEL LAPSE RATE: 8.0 – 8.5C
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 this evenings activity:
SPC HOMEPAGE LINK
https://www.spc.noaa.gov/classic.html
The following are animations of both the SCP and STP currently for tomorrow, however slight changes are possible between now and tomorrows model runs. The animation runs from 3:00 p.m. to midnight CST. The greater the value, the greater the risk to 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
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