# Presentation: 185926

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_**Presentation**_** **_**Outline**_** **

****     SPC Web Redesign**** **

****     Watch Probabilities**** **

****     Enhanced Thunder**** **

****     Day 4-8 Severe Weather Outlook**

## SPC Web Redesign

- Implemented on April 1st, 2005

- Major changes include:

- --	All white backgrounds

- --	Interactive front page with
-  	current Watches/MDs listed

- --	Added capability to retrieve SPC
- 	archived products

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## Watch Probabilities 

**Forecast 7 individual severe weather parameters. **

- 2 or more tornadoes

- 1 or more strong (F2-F5) tornadoes

- 10 or more severe wind events

- 1 or more wind events > 65 knots

- 10 or more severe hail events

- 1 or more hailstones > 2 inches

- 6 or more severe hail/wind events

**They are (in 10% increments from 0-100%) the probabilities of:**

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## Severe TSTM Watch #21 Probabilities

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## Tornado Watch #341 Probabilities 

- Tornado Watch #341 Probabilities

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## Tornado Watch #342 Probabilities 

- Tornado Watch #342 Probabilities

## Watch Probabilities 

**Provide better discrimination of the expected amount and intensity of severe weather events from one watch to another****.**

**Probability modifiers (low, moderate and high) still a work in progress.**** **

**Available to all on SPC web page.**** **

## SPC Enhanced Thunder Product

**Issued at 0600, 1300, 1630 and 0100 UTC.**

**Two thunder graphics  –  valid from 1200 (or time of issuance) until 0000 UTC and 0000 - 1200 UTC.**

**Probability Contours 10%, 40% and 70%.**** **

**Tue March 8th  -  product will be available on the SPC web for **_**all**_** customers**.

**Only 1 product issued at 0100 UTC.**

**Provides better temporal resolution and thunder coverage than routine Convective Outlook.**

## SPC Thunder Outlook issued Aug 15, 2004 at 0600 UTCvalid 15/1200 -  16/1200 UTC

##           SPC Enhanced Thunder Outlook issued Aug 15 at 0600 UTC,                                            		         valid 15/1200 - 16/0000 UTC

-           SPC Enhanced Thunder Outlook issued Aug 15 at 0600 UTC,                                            		         valid 15/1200 - 16/0000 UTC

## SPC Enhanced Thunder Outlook issued Aug 15 at 0600 UTC Valid 16/0000 - 16/1200 UTC

## SPC Enhanced Thunder Verification Aug 15, 2004;  Valid 15/1200 - 16/0000 UTC

## SPC Enhanced Thunder Verification Aug 15, 2004;  Valid 16/0000 - 16/1200 UTC

## Day 4-8 Severe Weather Outlook 

-  Product issued daily by 400 am cst (and cdt).

- Outlook areas only for expected organized severe convection in synoptically active patterns.

- Reasonable confidence for event occurring across a specific area before depicting a severe weather area

- Given model uncertainty/unreliability 4 or more days out,  only forecast severe weather areas when there is at least a 25% or higher probability for severe.

- Product available to _**only**_ noaa.gov IP addresses beginning on March 8th.

## Day 4-8 Severe Weather Outlook 

## 	PREDICTABILITY TOO LOW TO DELINEATE A     
	REGIONAL SEVERE WEATHER AREA 

	Area(s) of organized severe storms possible, but substantial differences in deterministic model solutions, or  ensemble guidance spreads, or lack of day-to-day continuity, etc., indicate large uncertainty in terms of location and/or probability of occurrence. 

**	****REGIONAL SEVERE WEATHER AREA **
**	****Area(s) of organized severe storms possible, but substantial differences in deterministic model solutions, or  ensemble guidance spreads, or lack of day-to-day continuity, etc., indicate large uncertainty in terms of location and/or probability of occurrence. **

- Day 4-8 Severe Weather Outlook

**POTENTIAL TOO LOW FOR A REGIONAL SEVERE WEATHER AREA**
**When the threat for a regional area of organized severe storms appears very low.**

## Day 4-8 Severe Weather Outlook

## Day 4-8 Severe Weather Outlook

- Day 4-8 Outlook available only to noaa.gov IP addresses beginning on March 8th.

-  A short text discussion will accompany graphic.

-  Many questions remain, such as:

-  What is best way to forecast severe weather                                        for the Day 4-8 period?

-  How do we receive effective feedback from those     who will use product?

## Summary 

- SPC web redesign will be implemented on April 1st.
- Watch Probabilities now available to _**all**_ on SPC web site.
- Enhanced Thunder Products available to _**all**_ on SPC web site beginning March 8th.
- Day 4-8 Severe Weather Outlook available to _**only**_ noaa.gov IP addresses beginning on March 8th.