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.
CATEGORICAL OUTLOOK CONVERSION TABLE FOR DAY 1 OUTLOOKS
The Storm Prediction Center (SPC), has issued a SLIGHT risk of severe thunderstorms in the current day 1 outlook: ACROSS PARTS OF SOUTHERN LOWER MICHIGAN INTO THE OHIO VALLEY…
…SPC SUMMARY…
Scattered thunderstorms capable of producing damaging winds, large hail, and a few tornadoes should develop across parts of the Ohio Valley and Lower Great Lakes this afternoon. Thunderstorms with mainly a large hail threat may occur tonight over parts of the central Plains.
DAY 1 OUTLOOK LINK
https://www.spc.noaa.gov/products/outlook/day1otlk.html
The SPC day 1 outlook map and NADOCAST maps should update automatically if changes occur. If not, click each, as they are linked.
SPC DAY 1 SEVERE THUNDERSTORM OUTLOOK MAPS (first image linked to current SPC outlook)
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.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point
DAMAGING THUNDERSTORM WINDS PROBABILITY
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
NADOCAST 12Z SIGTOR FORECAST UPDATE
Based on my analysis of the current outlook, CIPS, NAM and SPC SREF models, information derived from forecast indices indicates all threats today are probable, with a low probability for tornado activity over the Central Plains region. Based on analysis this morning, forecast severe and tornado indices differ somewhat between the 2 slight risk areas. Moderate deep layer shear, and somewhat stronger mid level lapse rates and CAPE values will allow for the probability of significant hail event over a small area of Kansas. Based on <100 m2/m2 SRH (0 – 1 km) and <250 m2/m2 (0 – 3km), the tornado threat SHOULD remain on the low end, while moderate deep layer shear and stronger SRH values indicate a little higher tornado threat at peak intensity of the indices, and any sufficient daytime heating. I am currently not expecting any strong tornadoes regarding today’s severe weather. The following were the forecast parameters and indices analyzed this morning and pertain to the Ohio valley and Great Lakes region, and represent the “peak” time of intensity.
SBCAPE: 1000 – 2000 j/kg-1
MLCAPE: 1000 – 1500 j/kg-1
MUCAPE: 1250 – 1500 j/kg-1
SRH 0 -1 km: 150 – 200 m2/s2
SRH 0 -3 km: 200 – 300 m2/s2
SRH EFFECTIVE: 100 – 200 m2/s2
L. I.: -1 to -5
STP: 1 – 3
SCP: 3 – 12
0 -6 km SHEAR: 40 – 50 kts
EFF. SHEAR: 40 – 45 kts
MID LEVEL LAPSE RATE: 6.0 – 7.0C
DEWPOINT: 58F – 63F
EHI: 1.5 – 2.3
TOTAL TOTALS INDEX: 49 – 52C
K INDEX: 26 – 32C
SWEAT INDEX: 400 – 500
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.
SWEAT INDEX CHART
The following are the SCP (Supercell Composite Parameter) and STP (Significant Tornado Parameter) forecast maps from the NAM model. Generally, the higher the values and brighter the color, indicates a greater probability of strong thunderstorm and tornadic activity over an area:
NAM SCP FORECAST (1:00 p.m. 17 APR. – MIDNIGHT EDT 18 APR.)
NAM STP FORECAST (1:00 p.m. 17 APR. – MIDNIGHT EDT 18 APR.)
SREF STP >1 PROBABILITY 2:00 P.M. EDT
5:00 P.M. EDT
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 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 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/
SPC HOMEPAGE LINK
https://www.spc.noaa.gov/classic.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 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)
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
WEST CENTRAL FLORIDA HURRICANE and SEVERE WEATHER FORECAST CENTER 