The Climate-Weather Link and U.S. Hazards Prediction By Ed O

1
The Climate-Weather Link and U.S. Hazards
PredictionByEd OLenicNOAA-NWS-Climate
Prediction CenterIAEM 50th Anniversary
Conference and ExhibitColumbus Convention Center
and Hyatt Regency HotelColumbus, OhioOctober
13, 2002
2
Sources of Variability
Time Scales of Variability

• Intra-Seasonal within season
• Inter-Annual year-to-year
• Decadal decade-to-decade

• Tropical intra-seasonal oscillations (MJO)
• El Nino/Southern Oscillation (ENSO)
• Trend, Pacific Decadal Oscillation (PDO)

3
Solar radiation gt Temperature gradients gt
Motions

• The sun is the source of all energy in the
  atmosphere-ocean-land system.
• The pole-to-equator temperature difference,
  created by sunshine heating the
  atmosphere-ocean-land system unevenly, drives
  large-scale atmospheric motions.
• Motions act to destroy temperature differences
  balance in-coming vs. out-going radiation.
• Tropical disturbances, e.g., El Nino, La Nina,
  MJO, PDO are particularly effective at changing
  this large-scale difference, or gradient
  (difference/distance).
• This changes the location and strength of the
  major jet streams, which affects the weather.
• Temperature gradients also cause disturbances on
  smaller space and time scales, monsoons,
  cyclones, fronts, squall-lines, thunderstorms,
  clouds, etc
• The oceanic circulation is important, too, but
  thats a whole other lecture.

4
Climate Versus Weather
Top Graph Observed daily average Temperature
(T), May 2000-April 2001 (jagged curve, an
example of weather), and 30-year average
(1971-2000) of daily average T (also called the
normal, (smooth curve) the standard definition
of climate) at Albany, New York. Note the
large day-to-day variability indicated by the
red (above-normal) and blue (below normal) daily
T events. Bottom Graph Result of
subtracting the normal from the daily average T
in the top graph and then performing a 31- day
running average. Note the expanded scale on the
lower graph. The extended periods of above and
below normal 31-day average T are, examples of
short-term climate variability. Green line is
the average of the departures over May 2000-April
2001.
5
Storms

• STORMS REGIONS OF DISTURBED WEATHER CLOUDS,
  PRECIPITATION, STRONG WINDS ASSOCIATED WITH
  EITHER
• LARGE-AMPLITUDE HORIZONTAL TEMPERATURE
  GRADIENTS IN MIDDLE LATITUDES (CYCLONES),
• OR
• OCEAN SURFACE TEMPERATURES EXCEEDING
• 26 ½0 C AND WEAK LARGE-SCALE VERTICAL WIND SHEAR
  IN THE TROPICS AND SUB-TROPICS (TROPICAL STORMS).
  

6
Coastal Population Rising
The population in regions subject to strong
coastal storms is rising rapidly. Many of these
people have little or no know- ledge of the
potential for disaster in these areas.
7
Insured Losses of U.S. Disasters, 1950-94
Hurricanes and winter storms rank among the most
expensive U.S. disasters
8
The Great Snow and Wind Storm of Thanksgiving,
1950
Unnamed wind storm November 23-December 2,
1950. An intense, slow-moving extra-tropical
storm along the U.S. East Coast was accompanied
by sustained gale-force winds for several days,
wind gusts to hurricane-force (including a gust
to 110 mph on a sky scraper in New York City),
wind-driven flooding near the coast (including 12
feet of flood water at La Guardia Airport), heavy
snow in Western Pennsylvania. East Coast and
Great Lakes shipping was severely impacted.
Record low temperatures were observed in the
South, including 3 degrees F at Atlanta, Georgia.
The insured loss from the storm was 6-7 B (in
recent dollars).
9
U.S. Hazards Assessmenthttp//www.cpc.ncep.noaa.g
ov/products/predictions/threats
U.S. Hazards
Assessment Temperature/Wind
Precipitation
Soil/Wildfire
Composite
10
U.S. Hazards Assessmenthttp//www.cpc.ncep.noaa.g
ov/products/predictions/threats
A Hazards conference call is held each Wednesday
at 2PM Eastern Time.

• Hazards Briefing Sequence 
• Satellite/Radar
• IR Anim Global, North America
• Water Vapor Anim
• US Radar
• Climate Monitoring
• SST Anim Glbl, Pac, Atl/E Pac
• 7d SST Pac, Atl/E Pac
• EQPAC T-Depth Plot
• EQPAC T-Depth Anim Wk, Mon
• Obs P 1/7d, 30d, 90d
• ENSO Bull Text, Fig 1, Fig 2
• Sea Level Anim
• Z Loops NH, Globe
• CDC OLR Anom
• Cities Temp
• Cities Precip
• Forecasts
• NCEP Ensembles

11
Linkage between weather and climate
Jet streams, tropical storms, Extreme events,
floods, diurnal cycle,
Weather
Reacts to changes in heat budget, temperature
gradient.
Reacts to changes in heat budget through changes
to planetary-scale temperature gradient, which
affect weather.
Reacts to changes in the global heat budget
Decadal Climate Variability
Short-term Climate Variability
Trends of unknown origin, Trends in ENSO AO,
Global Warming, Thermohaline Circulation,
Ultra-slow oscillations
ENSO, MJO, PDO (tropics) AO,
PNA, Storm Tracks, Droughts, (extra-Tropics)
12
El Niño / Southern Oscillation - ENSO

• El Nino warms the global tropics, strengthening
  the pole-equator temperature difference.
• El Niño causes drought in normally wet regions
  and floods in normally dry regions.
• La Nina cools the global tropics, weakening the
  pole-equator temperature difference.
• La Niña causes floods in normally wet regions,
  makes dry regions drier.

13
El NINO/Southern Oscillation
14
El Nino Global Precipitation Impacts
15
ENSO Impacts
16
U.S. ENSO Impacts
El Nino 1997-98
ENSO Impacts illustrate the basis of the
climate-weather link.




17
El Nino summer Few Atlantic Storms
18
La Nina summer Many Atlantic Storms
19
Observed and Annual Cycle of Precipitation near
SFO
El Nino-related Above normal rainfall
20
The Madden-Julian Oscillation (MJO) A
disturbance in tropical cloudiness, rainfall,
wind and pressure

• Consists of a cloudy, rainy, strong low-level
  westerly wind phase and a non-cloudy, dry,
  low-level easterly wind phase.
• Move from eastward from the Indian Ocean around
  the globe in 30-60 days. Disturbances are 1500
  km wide.
• Most active during ENSO-neutral years (especially
  just prior to El Niño).
• Affects the frequency of extreme weather events,
  such as floods, in winter, and tropical cyclones
  and monsoons, in summer.
• Low-level westerly wind bursts during cloudy
  phase warm the ocean, reverse easterlies,
  contribute to onset of El Nino.

21
Intra-Seasonal Variability of Hurricanes
Greenabove-average cloudiness and
rainfallBrownbelow-average cloudiness and
rainfall
Intra-Seasonal Variability of Hurricanes
Madden-Julian Oscillations (MJO) 30-60 day
disturbances in tropical cloudiness
22
When the MJO maximum in tropical rainfall shifts
eastward from Indonesia to the central tropical
Pacific, the jet stream over the North Pacific
gradually extends eastward towards the west coast
of the U.S. and intensifies. This pattern
favors the occurrence of heavy precipitation
events, along the Pacific Northwest coast.
23
TROPICAL CYCLONES
Hurricane Floyd 2029 UT (0429 EST) Sep 14, 1999
24
U.S. Hazards Assessment
25
MAJOR REGIONS OF TROPICAL STORM ACTIVITY
26
Atlantic Tropical Storm Climatology
27
Eastern North Pacific Tropical Storm Climatology
28
Atlantic Tropical Storms, 1967-2000
Low numbers of storms does not imply weak storms
Category 5
Andrew
29
Extra-Tropical Cyclones
GOES water vapor 8.1 microns Feb 14, 2002
30
North Atlantic Oscillation (NAO)
The North Atlantic Oscillation is the pattern
most-closely associated with winter weather over
North America, the Atlantic and Europe. The
pattern at right shows how the pattern differs
from the 30-year average. Red is for abnormally
high pressure, blue is for abnormally low
pressure. The pattern shown is the positive
phase. The reverse pattern is the negative phase.
31
NAO Phases/Impacts
32
NAO Index, Monthly Mean, 1950-2002
33
AO-ENSO Relationships JFM Temperature Anomaly
(0C) by AO and ENSO Phase
34
Global Temperature Trends
35
IPCC Estimate of Impact of Global Warming on
Storm Activity
36
Summary

• Climate average of weather but controls
  statistics of weather. This is the basis of
  the climate-weather link.
• U.S. Hazards Assessment emphasizes C-W Link.
• Tropical disturbances, MJO, ENSO cause much of
  the observed intra-seasonal to inter-annual
  variability in storms in low and middle
  latitudes.
• MJO is related to intense rain events in NW U.S.
• El Nino brings enhanced storminess and damage to
  the California coast.
• Tropical storm frequency shows large variability
  on decadal and longer time scales.
• - AO phase is related to strong U.S. winter
  cyclones.
• IPCC estimates storm strength and frequency will
  rise.
• http//www.wmo.ch/index-en.html