2. MID APR-MID JUN PRECIPITATION
• Several northern storms brought
beneficial rains to northern/western
NV, the Sierra & northeast CA
• 8-10 inches in the Sierra!
• 100-150% of normal
• Rest of CA saw lighter rainfall
amounts
• Storms in southern stream
brought beneficial rains to
much of AZ & southeast CA
• 150-200% of normal
Total Precipitation 4/15/15 – 6/14/15
3. DROUGHT UPDATE
• Late spring storms
• Beneficial storms – short term
• Not widespread enough and/or amounts
were not significant enough
• Resulted in little change in severity of
drought conditions
• Long-term severe or greater drought
continues
• Some level of drought continues
in 74% of the west and 97% of CONUS FR9
4. HAWAII DROUGHT UPDATE
• Overall dry pattern has developed in recent
weeks (except Kauai)
• Dry pattern is forecast to continue over all
islands
• Some drought development on Hawaii and
Maui
5. ENSO OUTLOOK
• CPC continues an El Niño Advisory
• A >90% chance that El Niño
conditions/impacts will continue
through the Northern Hemisphere
fall 2015
• Around an 85% chance that it will last
through the 2015-16 winter
• Models are more robust this month vs.
last month for the upcoming winter
• Supported by:
• Increased SST anomalies
• Increased subsurface temperatures
• Enhanced convection over the Date
Line
• Increased persistence of low-level
westerly winds
Weak
Moderate
Strong
6. 30/90/180 DAY OUTLOOK
• Above normal temperatures are favored
throughout the far west thru Sep 2015
• Especially northern CA/western NV
• Above normal precipitation is favored
over parts of eastern NV/NE AZ…an
extension of the wet weather expected
over the Rockies this summer
• Above normal precipitation is favored
over all of AZ, southern CA, and extreme
southern NV in the fall/early winter
• In association with an expected active
eastern Pacific TC season
• Expected influence from a moderate
to possibly strong El Niño condition
Jun 2015 Jun 2015
JAS 2015 JAS 2015
OND 2015 OND 2015
7. DROUGHT OUTLOOK
• Drought is forecast to persist
or worsen through Aug 2015
• Essentially all of CA & NV
• Potential drought impacts
• Continued stress on water resources
• Water rationing
• Water quality
• Greater number of dust storms
negative impacts on air quality
• Crop damages
• Livestock sell off
• Widespread fire season
• Influence/improvements from the
developing El Niño not expected
until fall/winter
9. EL NIÑO & THE NORTH AMERICAN MONSOON
• Previous 5 established or emerging
El Niño years were examined
• Trend toward a delayed onset
• Trend is towards lower than
normal rainfall totals during these
El Niño seasons
• Certainly not every year
• Even in a typical monsoon season
• Rainfall distribution can be
extremely disparate
• Making a seasonal forecast based
on El Niño for any given location
carries very limited skill
Rainfall totals for AZ WFO locations
http://www.atmo.arizona.edu/~castro/Reviewedpubs/R-1.pdf
13. 2015 EP Season Outlook
15-22 Named Storms
7-12 Hurricanes
5-8 Major Hurricanes
“El Niño is the main climate factor expected to enhance
the 2015 eastern Pacific hurricane season”
http://www.nhc.noaa.gov
14. CP Tropical Weather Climatology
• Central Pacific (Avg/Yr)
– 4-5 Tropical Cyclones
• 1970 to 2014
– 186 Tropical Cyclones
www.weather.gov/cphc
• Three Direct Hits(since 1950)
– Dot (1959), Iwa (1982),
Iniki (1992)
– Total damage more than
$3.25 billion
•
16. CP TC Climate Factors
• El Niño conditions
typically mean a more
active TC season in the
Central Pacific.
(6-7/yr since 1970)
• La Niña conditions
typically mean a less
active TC season in the
Central Pacific.
(3/yr since 1970)
18. 2015 CP Season Outlook
5-8 Tropical Cyclones
70% Above Normal Season
25% Normal Season (4-5 TCs)
5% Below Normal Season
El Niño conditions expected to strengthen during the season
19. PACIFIC TROPICAL CYCLONE SUMMARY/OUTLOOK
• Eastern Pacific
• 15-22 Named Storms
• 7-12 Hurricanes
• 5-8 Major Hurricanes
• Central Pacific
• 5-8 Tropical Cyclones
• Western Pacific
• Five named TCs already!
• 1CAT5, 1CAT3, 1CAT1
• Higher than normal
• >/= to 30 named TCs
• Southern Pacific
• Off Season
2014 tracks
Pacific Typhoon Tracks 1980-2005
20. SUMMARY
• Spring storms brought beneficial rains in the short-term to portions of northern
CA/NV, the Sierra, and much of AZ and southeast CA
• Resulted in little change in severity of drought conditions
• Long-term severe or greater drought continues
• 97% of CONUS FR9
• Drought is forecast to persist or worsen through Aug 2015
• Nearly all of CONUS FR9
• Numerous potential impacts continue
• An El Niño Advisory continues
• >90% chance it will continue through the NH fall 2015 and likely through the
upcoming 2015-16 winter
• While intensity is difficult to forecast, a weak to moderate El Niño winter is likely and
a moderate to strong El Niño winter is possible
• Above normal temperatures are favored throughout much of the far west through
summer 2015
• A delayed start to the summer monsoon is favored
• A trend exists toward lower summer monsoon seasonal rainfall but this skill is very
limited
• Above normal precipitation is favored over all of AZ, southern CA, and extreme
southern NV for the fall/early winter in association with the developing El Niño
21. Questions and Contacts
WR Duty Officer 801-524-7907 wr.roc@noaa.gov
Bill Ward 808-532-6415 bill.ward@noaa.gov
www.weather.gov
"Climate is what you expect,
Weather is what you get". ~ R. Heinlein
http://droughtmonitor.unl.edu/Home/RegionalDroughtMonitor.aspx?west
Updates every Thursday
http://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/
Updates first and third weeks of each month
http://www.cpc.ncep.noaa.gov/products/predictions/30day/
http://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=1
Monthly updates last day of month
3-month updates mid-month
Looking historically at Jun-Jul-Aug precipitation totals across the state, there is a weak correlation between El Nino and reduced rainfall across the central and southern parts of the state. Little correlation exists over the northern part of the state. It must be re-iterated this connection is only weak, and there are several competing influences on summer monsoon weather. Also, just by the nature of monsoon thunderstorms, rainfall amounts and even seasonal anomalies can be very localized even within a larger climate region.
