During SFE 2016, participants complete a variety of forecast
and verification exercises. While some of each day is spent as one large group,
such as during the morning hand-analysis of maps and the map discussion, the
remainder of the day has participants split into two desks. Each desk has a
different focus when issuing forecasts, and completes a different set of daily verification exercises. However, participants rotate between desks
throughout the week, ensuring that they get to experience all of the activities SFE 2016 has to offer.
One of these desks is called the Individual Hazards desk. This desk forecasts the individual severe
convective hazards of tornadoes, hail, and wind. While the SPC currently issues
individual hazard probabilities for their operational Day 1 convective outlook, the
individual hazards desk issues two four-hour probabilities of individual hazard
forecasts (18Z-22Z and 22Z-02Z) in addition to the full period Day 1 outlook. They
also issue a Day 2 forecast for hail, tornadoes, and wind. All experimental
forecasts are displayed along with “practically perfect” verification for
evaluation in the SFE the following day under the Individual Hazards link on this website. While the full period outlooks are composed as a group at the individual hazards desk, each participant issues their own four-hour probabilities on Google Chromebooks, using the Phi tool.
Short-term individual hazard forecasts are being computed to test the feasibility of issuing shorter-term outlooks than are currently operational. Operationally, these shorter time periods are currently addressed on an as-needed basis (i.e., Mesoscale Discussions). Additionally, the extension of convection-allowing guidance into the Day 2 period allows for long-term insight into the mode of convection, which can be used with environmental information to deduce which hazards may be the primary threat for a day. CAM guidance supports proxies for severe weather such as updraft helicity and hail size forecasts, rather than relying solely on the environment that larger-scale guidance provides. These forecasts were also issued during SFE 2015, the results of which can be found here.
The other desk is called the Total Severe Desk. This desk, as the name implies, focuses more on the total probability of any severe hazard. Operationally, the SPC Day 2, Day 3, and Day 4-8 convective outlooks consist of total severe probabilities and do not probabilisitically discern between the different hazards. This desk issues a total severe probabilistic forecast for the Day 1 full period (16Z - 12Z the following day), Day 2, and then for five four-hour periods (18-22Z, 20-00Z, 22-02Z, 00-04Z, and 02-04Z). These four-hour probabilities are created as a group, and are used as guidance for the forecasters to issue individual isochrones - lines of equal time - on the Google Chromebooks. Each forecaster uses the Phi tool to issue five isochrones in the morning, delineating the time of maximum severe reports across the forecast area of interest. These experimental isochrones are also available online the day after the forecasts are issued, alongside each experimental four-hour probabilistic forecast. Stay tuned for information on these isochrones and their interpretation in an upcoming post, as they have been a major focus of discussion on the total severe desk for the first two days of the experiment!
Short-term individual hazard forecasts are being computed to test the feasibility of issuing shorter-term outlooks than are currently operational. Operationally, these shorter time periods are currently addressed on an as-needed basis (i.e., Mesoscale Discussions). Additionally, the extension of convection-allowing guidance into the Day 2 period allows for long-term insight into the mode of convection, which can be used with environmental information to deduce which hazards may be the primary threat for a day. CAM guidance supports proxies for severe weather such as updraft helicity and hail size forecasts, rather than relying solely on the environment that larger-scale guidance provides. These forecasts were also issued during SFE 2015, the results of which can be found here.
The other desk is called the Total Severe Desk. This desk, as the name implies, focuses more on the total probability of any severe hazard. Operationally, the SPC Day 2, Day 3, and Day 4-8 convective outlooks consist of total severe probabilities and do not probabilisitically discern between the different hazards. This desk issues a total severe probabilistic forecast for the Day 1 full period (16Z - 12Z the following day), Day 2, and then for five four-hour periods (18-22Z, 20-00Z, 22-02Z, 00-04Z, and 02-04Z). These four-hour probabilities are created as a group, and are used as guidance for the forecasters to issue individual isochrones - lines of equal time - on the Google Chromebooks. Each forecaster uses the Phi tool to issue five isochrones in the morning, delineating the time of maximum severe reports across the forecast area of interest. These experimental isochrones are also available online the day after the forecasts are issued, alongside each experimental four-hour probabilistic forecast. Stay tuned for information on these isochrones and their interpretation in an upcoming post, as they have been a major focus of discussion on the total severe desk for the first two days of the experiment!
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