AccuWeather Winter
Forecast 2014-2015
Winter 2013-2014 sea surface temperatures (SST)
compared to normal
Very
Warm
Cool
Weak La Nina
Warm
Normal winter upper air
pattern (+PNA: ridge west, trough east)
Winter 2013-2014 upper air pattern
(Stronger +PNA ridge west, trough east)
Winter 2013-14 surface temperature (C) departures
U.S. surface temperature (F) departures
U.S. surface precipitation departures
SET UP FOR WINTER OF
2014/2015
European global model (ECMWF)
forecasted upper air pattern for DJF
(+PNA pattern for North America)
Current situation: very warm northeast Pacific, + PDO,
+AMO, neutral to weak El Nino
Very
Warm
+PDO
Neutral to weak El Nino
+AMO
PDO Index
AMO Index
Winter 2013-2014 SST again…
Very
Warm
Cool
Weak La Nina
Warm
North American Multi-Model Ensemble (NMME)
SST departure forecast for DJF
Warm
Cool
El Nino
International Multi-Model Ensemble (IMME)
SST departure forecast for DJF
Warm
Cool
El Nino
International Research Institute/Climate Prediction
Center (IRI/CPC) ENSO probability forecast
International Research Institute/Climate Prediction
Center (IRI/CPC) ENSO Ensemble Plume forecast
Mod El Nino
Weak/Mod El Nino temperature
departure analogs
Weak/Mod El Nino precipitation
departure analogs
ANALOGS, CLIMATE SIGNALS,
AND ADDITIONAL VARIABLES
Pacific Decadal Oscillation (PDO): + or warm PDO in the winter can create drier than
normal conditions in the Northwest and wetter than normal conditions in the Southeast
El Nino central Pacific (CP) vs. eastern Pacific (EP): CP leads to a drier north and wetter
south pattern in the western U.S., EP leads to an overall wetter western U.S.
Artic Oscillation (AO): Jet stream flow across Canada and northern U.S, negative leads to
blocking and Artic air deflected southward into the U.S., positive leads to milder zonal
flow across Canada and northern U.S.
Quasi-Biennial Oscillation (QBO): Stratospheric warming (-QBO) or cooling (+QBO) at
~75,000 feet. Combined with the solar cycle, it can enhance the track of the jet stream
across North America. Stratospheric warming/solar minimum generally leads to more
blocking in the jet stream and cold outbreaks into the eastern U.S.
Eastern Pacific Oscillation (EPO): Jet stream flow across the north Pacific. Negative leads
to blocking over north Pacific and positive leads to progressive zonal flow into western
Canada. Winter of 2013-2014 was mostly negative and blocked.
Siberian Snow: A large and positive buildup of snow cover in Siberia or Eurasia through
the entire month of October can lead to jet stream blocking later in the winter, i.e. cold
shots of Arctic air into the eastern U.S.
Higher ranked analog years DJF
temperature departures
Higher ranked analog years DJF
precipitation departures
ACCUWEATHER FORECAST FOR
THE WINTER OF 2014/2015
NOAA winter temperature forecast
NOAA winter precipitation forecast
HEATING DEGREE
DAYS EXPECTED
THIS WINTER
DEC
JAN
FEB
TOTAL
Edinburg, TX
+40
+66
+60
+166
Alice, TX
+42
+74
+76
+181
Katy, TX
+40
+93
+84
+217
Natchitoches, LA
+57
+119
+92
+268
Monroe, LA
+62
+126
+90
+278
Lake Charles, LA
+65
+99
+81
+245
New Orleans, LA
+68
+87
+76
+231
Greenville, MS
+55
+130
+93
+278
Columbus, MS
+64
+136
+106
+306
HEATING DEGREE
DAYS EXPECTED
THIS WINTER
DEC
JAN
FEB
TOTAL
Nashville, TN
+50
+153
+109
+312
Danville, KY
+46
+132
+109
+288
Huntington, WV
+37
+121
+101
+259
Zanesville, OH
+30
+118
+105
+253
Pittsburgh, PA
+37
+102
+84
+223
New Castle, PA
+28
+104
+88
+220
Bradford, PA
+31
+90
+78
+199
Jamestown, NY
+25
+96
+81
+202
Buffalo, NY
+25
+99
+81
+205
HEATING DEGREE
DAYS EXPECTED
THIS WINTER
DEC
JAN
FEB
TOTAL
Rochester, NY
+25
+87
+78
+190
Syracuse, NY
+22
+74
+76
+172
Albany, NY
+9
+22
+70
+146
Sussex, NJ
+16
+37
+81
+134
White Plains, NY
+9
+19
+78
+106
Hartford, CT
+5
+9
+78
+92
Providence, RI
+5
+19
+56
+80
Boston, MA
-5
+16
+42
+53
Manchester, NH
-5
+16
+48
+59
Highlights and impacts for winter 2014/15
-Stormy for parts of the Tennessee Valley, Gulf Coast, Central and
Southern Appalachians.
-Active southern branch jet can lead to developing waves and big
storms from the lower Mississippi Valley to the Mid Atlantic and
Northeast.
-Coldest air, compared to normal, centered over the Tennessee Valley.
-Warmest air, compared to normal, centered over the interior
Northwest.
-Driest region, when compared to normal, interior Northwest.
-Wettest areas will be the interior southwest and central Gulf Coast,
perhaps including Florida as well.
Questions?
Comments?
Paul Pastelok or Don Coash