Nowcas asting i in Sea Seattle Clifford Mass and Jeff Baars - PowerPoint PPT Presentation

Nowcas asting i in Sea Seattle Clifford Mass and Jeff Baars Department of Atmospheric Sciences University of Washington Seattle, Washington

Ca Can n a major or city s save e money a and l nd lives es us using nowcas asting? g? • Prepare for and respond to windstorms • Prepare for and respond to snow and ice events • Warning and responding to heavy precipitation events

The Ci he City of of Sea Seattle e Has Inves ested ed i in Three ee Nowcasting ng A Applications ns

RainWatc atch

Sno SnowWatch ch

WindWatc atch

RainW nWatch w h was b built a after er h heavy r rain f n flooded ded parts of of Sea Seattle an and a a wom oman d died i in her b er bas asem ement

Sho Short-Ter erm W Warnings gs A Allow t the he Ci City To o Int ntervene

Ra RainWatch Ca Capa pabilities es • Calibrates radar estimates of precipitation using local rain gauges • Calculates 1-hr, 6-hr, 24-h, and 48-h totals. • Provides a 1-h precipitation forecast based on radar extrapolation • Also provides the NOAA HRRR (High Resolution Rapid Refresh Forecast) for the near future. • Warns Seattle officials when observed or forecast precipitation amounts exceed pre- determined values. • Available at http://www.atmos.washington.edu/SPU/

Sn SnowWatch ch Seattle i e is crippl pled b ed by even light am amou ounts ts of s snow ow

In n December o of 2008 a 2008 a series o of mode dest sno nowstorms br brough ght t the he c city t y to a standstill f for 2 2 weeks, w , with c costs ts of f hundreds o of f millio llions o of f dolla llars Needed better forecasting/ nowcasting of snow to prepare and clear roads

Sno SnowWatch ch • Monitors both high-resolution model forecasts AND the National Weather Service gridded snow forecasts. • Sends warnings to Seattle Department of Transportation personnel when a snow or ice threat exists, including road surface temps <+34°F

Sh Shows c current 2 t 2-m a air t temper peratures es a and r roadw dway temper peratures es, a as well a as temper peratur ure c e chang nge

And m d much m h more, e, s such a as deter ermini ning t ng the f e freezing ng level u usi sing v vert rtical so sounders a s and a aircraft asc scents/ s/desc scents

Sea Seattle e ha has ha had d far be better er r res espo ponse e to o ice e and nd sno now a after er Sno SnowWatch

WindWatc atch

The P Paci cific c North thwest I t Is Hit B t By Paci cific c Cycl clones w with th Winds ds E Equi quivalen ent t to Categ egory 2 2 Hu Hurricanes nes

Why W Wind N Nowcasting f g for or Utilities es? • Mobilize enough personnel to deal with damage • Secure resources (e.g., replacement parts) • Stage equipment and personnel in correct parts of service area. • Warn public to prepare (e.g., secure batteries, keep away from trees)

Sea Seattle e Ci City Ligh ght W Wanted ed a a Ca Capa pable e Nowcasting S System: WindWatc atch • Monitors high resolution forecasts: • University of Washington WRF forecasts (12-4-1.3 km grid spacing) • NOAA/NWS High Resolution Rapid Refresh (HRRR) • Monitors observed wind speed at all local mesonet stations • WARNS via email when a threat exists.

Major Nowcasting Game Changer: HRRR (High Resolution Rapid Refresh) • Initialized every hour, with 15 hour forecasts • Uses all available mesoscale information. • 3-km grid spacing • Added to WindWatch

HRRR has radically changed nowcasting in the U.S.

WindWatc atch I Implicat ations • Has greatly enhanced Seattle City Light’s ability to deal with windstorms • Power is restored more quickly than neighboring utilities

Nowcasting ng app pps a also ha o have e rel elevance t nce to o gl global war arming r g resilience As the earth warms and the climate becomes more extreme in some locations, state-of-science nowcasting can provide the last line of defense for climate-related extreme weather.

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