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

• r 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

• f 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

• f
• f Sea

Seattle an and a a wom

• man 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

• 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

• unts

ts

• f s

snow

• w

In n December o

• f 2008 a

2008 a series o

• f 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

• f

f millio llions o

• f

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

• 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

• r 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

• have

e rel elevance t nce to

• 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.

The En End