The following report was written by American Weather and Hydrology, LLC and confirms my thoughts regarding El Nino and the comng winter.

AMERICAN WEATHER & HYDROLOGY, LLC

"Your Weather Forecast & Seasonal Outlook Solution"

JULY, 2014

SPECIAL, MULTI-SEASONAL EL NINO OUTLOOK

AUGUST, 2014 – MARCH 2015

CALIFORNIA

OUTLOOK SUMMARY:

Map of Recent Ocean Temperature Anomalies

 

 

 

(from NOAA/NCEP). SENT UNDER SEPARATE COVER.

Explanation: This map of sea surface temperature anomalies covers the entire Pacific Ocean, Atlantic, & Arctic.

The anomalies are the departures from normal in degrees C for July 16, 2014, compared to historical average sea surface temperatures for this time of the year. (1 degree C = 1.8 degrees F 5 degrees C = 9 degrees F)

Latest Equatorial Pacific Ocean Temperature Developments

 

 

 

: La Niña is long gone, and El Nino has taken its place. We have not seen anything like this since 1997-1998. Water temps are pretty warm now, and continue to warm, although they are pulsating slightly. This pattern is associated with large, mid-latitude storms, energized by the low-latitude subtropical jet stream…which I cannot wait to see develop…probably some time in November. Once the Pacific storms associated with the subtropical jet stream get going, they will be warmer, holding much more water vapor…and could be relentless if all the parameters come together.

Latest North Pacific Ocean Temperature Developments

 

 

 

: In the North Pacific, we have a large warm-water plume still present due west of northern CA and Southern Oregon. There is a cooler wedge in-between, to the south of the warm water, and north of the developing El Niño. Ocean temps along the Southern CA coast are running warm, from Ventura south to the Mexican Border. Ocean temps are around 68F in the Ventura Harbor,, and as warm as 77F in the San Diego Bay. This area of warming will probably pulsate some, and peak out some time by October…Then the jet stream begins to strengthen from the north, and splits in two…polar jet and the southerly jet, knows as the subtropical jet – something that we really have not seen for some time.

Updated predictions:

 

 

 

With El Niño in place now, we should see some periods of tropical influence, perhaps even more when hurricanes really get going by late August. With the water so warm by then, I would not be surprised if So CA gets hit by a tropical storm…which will dump quite a bit of rain on the southland, perhaps a record amount. The Sierra Nevada should continue to have many days of rain -- thunderstorms, the general flow from the SE. The last OUTLOOK that Dr. Pyke and I put together had that large high pressure system way to the west…and was supposed to stay put…just east of Japan…but, the whole warm-water plume drifted eastward and surfaced in the worst spot possible, by mid-December…and then sat, building a high-pressure ridge over us that we did not expect at all. Very humbling to say the least. This water year will be different.

Storm systems should be much warmer…and more frequent…as the low-latitude subtropical jet will be energized, pushing along rather large storm systems from the west. Pineapples will occur…as moist air taps into the surface water temps…helping to deepen surface lows.

Current Patterns:

 

 

 

The effects of El Niño can be felt already, as this ENTIRE spring has had perhaps only 3 days of drizzle…as the marine layer has continued to warm and stabilize. Little if any rising occurring on the inside of the marine layer and struggling Catalina eddies. Ocean temps are unseasonably warm right now. They are at the very least, 5-7 degrees warmer than averages for this time of the year. San Diego should be only around 66F at best…but is close to 10 degrees warmer at this time…as warm as 77F…just a few days ago.

Remainder of summer:

 

Our long-range outlooks are based mostly upon Pacific Ocean temperature anomalies, and we generally forecast conditions over a month at a time (no individual day-to-day predictions). However, the remainder of summer and into fall has the benefit of El Niño, now in place and still strengthening…And it should last at least through November, before it begins to wane. There will be enough energy to spawn decent size storms across the Pacific…and they should get quite large, rivaling some of the biggest winter storms in 1997-1998

Summer should experience at least a few days of rain for the So CA area, mainly due to tropical flow. Temps will near average to above average. It is going to be a rather humid summer, especially in August and September.

If no hurricanes send a huge plume of moisture toward So CA…then we may not experience rain during early fall. However, Pacific storms could begin as early as late October…as we will not rely upon averages and climatology…since we will be going into a wet pattern.

October:

 

We can expect many warm to hot days…with some mountain and desert thunderstorms. There could be moisture flowing in from hurricanes south of us. Most of these storms pass from east to west, but one could arc to the north and graze California…giving the Southland unseasonably heavy rain. So there is clearly a chance of that…and that is a side swipe. There is also the chance of a direct hit of a downgraded hurricane, or tropical storm to slam into

So CA…which would end up giving the southland record rains. Interesting to see what will happen. Ocean temps in the San Diego Bay may still be hovering around 78-80F by then --.almost enough to sustain a tropical storm.

November:

 

Ocean temperature patterns will be cooling a bit…but still warm. The Polar Jet stream will be strengthening, as storm systems will already be moving in from the Pacific NW with a strong southward component to the storm systems. One or two may hit So CA…and noticeable large rain drops may occur with these storms, as the high amounts of precipitable water will be evident. No cold outbreaks are expected.

High pressure may struggle to develop…as the ocean water, being rather warm, will make the atmosphere much more buoyant, especially along the Central CA coast.

 

The number of days with measurable rain will probably be near to slightly above normal for the month of November. There also could be a number of thunderstorms, especially in Southern CA.

Winds will likely be moderate to strong – mostly storm-related -- throughout much of November.

December:

 

The subtropical jet stream should be pretty well established by then…and several storm systems should occur…and perhaps even intensify. There is a possibility that at least one month during the winter could end up being quasi-dry, if a stationary high pressure blocking ridge temporarily develops to the W-NW…but I am not seeing that as likely to occur…although one never knows.

Precipitation totals for December will probably be near average or slightly lower…to the south, and rainfall amounts significantly higher in Northern CA.-- something that we have not seen in years. We are long overdue for this much- welcomed pattern in the northern and central part of the State. Snow levels during December 2014 should be about average for Northern CA, but will be fairly high, the further south one goes.

January:

 

2015 may have a break for a week or two, before the General El Niño Storm system kicks in; and as they do…they could be relentless…with many days of rain…minor to major flooding and mud flows near burn areas.

February:

 

My thinking February will be the wet month…very wet. Continued pattern of one large storm after another to occur…energized by El Niño. These will be warmer storms, with snow levels pretty much above 6500’. Some colder sectors of the storms could briefly drop snow as low as 4500’,,,but then warming rains will likely occur with the arrival of new storms to wash the snow away.

March:

 

This month has the tendency to see the formation of cut-off lows, and with still, warmer than average ocean temps in place, severe storms may be on the menu. Small tornadoes could occur, especially if a cut-off low spins overhead and the timing is just right. Also, some colder storms may develop…so thunderstorms will be more frequent, often with lower snow levels. March may see more snow below 6000’ than any other month of winter 2014-2015.

Extended outlook through Spring 2015:

 

The pattern of October-March should continue well into the Spring of 2015, although rainfall totals and numbers of rainy days will decrease seasonally in April and May. Users of American Weather’s daily forecasts will still need to follow day-to-day rain threats into May and probably even into June. Then, an active summer monsoon appears likely.

The tables below represent our latest predictions of rainfall and temperature for November 2014 – March 2015.

(rainfall averages are based upon 30-year NOAA normals, but see note about Van Nuys Airport)

Nov Dec Jan Feb Mar Total

Rainfall Averages, Santa Rosa

 

4.04 6.19 5.93 6.02 4.53 26.71

Predicted rainfall amounts 2.59 11.02 10.56 15.71 10.33 50.21

Predicted rainfall % of normal 94 178 210 261 228 188

Predicted rainfall days of 0.10" or more 10 18 20 23 19 90

Rainfall Averages, San Francisco Airport

 

2.38 4.03 4.19 4.06 2.96 17.62

Predicted rainfall amounts 2.19 6.21 9.09 10.72 6.90 35.11

Predicted rainfall % of normal 92 154 217 264 233 199

Predicted rainfall days of 0.10" or more 9 14 18 21 17 79

Rainfall Averages, Oakland

 

2.89 4.48 4.71 4.50 3.39 19.97

Predicted rainfall amounts 1.62 6.81 10.79 12.11 8.58 39.91

Predicted rainfall % of normal 86 152 229 269 253 200 Predicted rainfall days of 0.10" or more 9 14 17 22 19 81

Rainfall Averages, San José

 

1.68 2.61 3.07 3.11 2.54 13.01

Predicted rainfall amounts 1.36 3.60 7.09 8.40 6.30 26.75

Predicted rainfall % of normal 81 138 231 270 248 206

Predicted rainfall days of 0.10" or more 6 12 15 20 17 70

Rainfall Averages, Monterey

 

2.32 3.41 4.40 3.92 3.38 17.43

Predicted rainfall amounts 1.76 3.92 10.38 11.29 8.52 35.90

Predicted rainfall % of normal 76 115 236 288 252 206

Predicted rainfall days of 0.10" or more 7 12 14 19 15 69

Rainfall Averages, Paso Robles

 

1.27 2.41 3.30 3.23 2.78 12.99

Predicted rainfall amounts 0.93 2.41 7.95 9.75 7.34 28.38

Predicted rainfall % of normal 73 100 241 302 264 218

Predicted rainfall days of 0.10" or more 6 10 12 17 14 59

Rainfall Averages, Santa Maria Airport

 

1.33 2.12 2.75 2.99 2.64 11.83

Predicted rainfall amounts 0,85 2.01 6.82 9.15 7.13 25.93

Predicted rainfall % of normal 64 95 248 306 270 219

Predicted rainfall days of 0.10" or more 5 8 10 15 11 49

Rainfall Averages, Santa Barbara

 

1.79 3.04 4.36 4.55 2.92 16.66

Predicted rainfall amounts 1.06 2.68 10.59 14.01 7.65 35.99

Predicted rainfall % of normal 59 88 243 318 262 216

Predicted rainfall days of 0.10" or more 4 7 11 16 11 49

Rainfall Averages, Ventura

 

1.39 2.51 3.61 3.94 2.79 14.24

Predicted rainfall amounts 0.79 2.16 9.21 13.24 7.48 33.08

Predicted rainfall % of normal 57 86 255 336 268 232

Predicted rainfall days of 0.10" or more 4 6 11 16 11 48

Rainfall Averages, Los Angeles Downtown (USC)

 

1,04 2.33 3.12 3.80 2.43 12.72

Predicted rainfall amounts 0.56 1.86 8.08 13.87 7.27 31.64

Predicted rainfall % of normal 54 80 259 365 299 249 Predicted rainfall days of 0.10" or more 3 4 10 15 11 43

Rainfall Averages, Santa Ana Fire Station

 

1.15 2.10 2.52 3.39 2.14 11.30

Predicted rainfall amounts 0.63 1.55 6.78 12.98 6.61 28.55

Predicted rainfall % of normal 55 74 269 383 309 252

Predicted rainfall days of 0.10" or more 3 4 9 14 10 40

Rainfall Averages, San Diego Airport.

 

1.01 1.53 1.98 2.27 1.81 8.60

Predicted rainfall amounts 0.61 1.01 5.45 9.13 5.76 21.96

Predicted rainfall % of normal 60 66 275 402 318 255

Predicted rainfall days of 0.10" or more 3 4 8 14 10 39

Rainfall Averages, Van Nuys Airport.

 

0.99 2.23 2.81* 3.23 2.50 11.76*

Predicted rainfall amounts 0.57 1.90 7.56* 12.02 7.80 29.85*

Predicted rainfall % of normal 58 85 269* 372 312 254*

Predicted rainfall days of 0.10" or more 3 4 11 16 12 46

Rainfall Averages, San Bernardino Fire Station

 

1.29 2.41 3.15 4.06 2.53 13.44

Predicted rainfall amounts 0.63 1.88 8.28 15.35 8.68 34.82

Predicted rainfall % of normal 49 78 263 378 343 259 Predicted rainfall days of 0.10" or more 3 4 10 15 13 45

NOTE: Van Nuys January normal precipitation, as published by two sources as 1.81 inches, and double-checked here, may be erroneously low. A figure like 2.81 inches, would seem more likely, and is used here. It makes the 5-month total 11.76 inches instead of 10.76 inches. Our prediction for January 2015 is 7.56 inches, and our pre cent of normal of 269% is based upon a normal of 2.81 inches. It is more consistent with the other months and with the numbers at other nearby stations.

NOTE: The average number of rainy days per month (0.10" or more) during the winter (Dec-Mar) ranges from 10 to 13 days in the Bay Area, increasing to the north, and 5 to 7 days in Southern CA. November averages about 3 fewer days per month, both north and south.

 

Our predictions for 2014-2015 are for rainfall to get off to a slow start in November and December, but becoming well above the normal numbers everywhere for the period Jan-Mar 2015 and for the season as a whole.

Temperature predictions (relative to long-term averages), deg F Nov Dec Jan Feb Mar Average

Average Max Temperatures, north of Golden Gate +1 0 0 -1 -2 -0.4

Average Min Temperatures, north of Golden Gate +1 +1 +1 +1 -1 +0.6

Average Max Temperatures, Bay Area +1 0 0 -2 -2 -0.6

Average Min Temperatures, Bay Area +1 +1 +1 +1 -1 +0.6

Average Max Temperatures, Monterey-Paso Robles +1 0 0 -1 -3 -0.6

Average Min Temperatures, Monterey-Paso Robles 0 -1 0 +1 -2 -0.4

Average Max Temperatures, Santa Maria-Santa Ynez Valley +1 +1 0 -1 -3 -0.4

Average Min Temperatures, Santa Maria-Santa Ynez Valley -1 -2 -1 +1 -2 -1.0

Average Max Temperatures, Santa Barbara-Ventura +1 +1 +1 -2 -2 -0.2

Average Min Temperatures, Santa Barbara-Ventura 0 -1 0 +2 -1 0.0

Average Max Temperatures, Los Angeles County +2 +2 0 -2 -3 -0.2

Average Max Temperatures, Los Angeles County +1 +1 +1 +2 -1 +0.8

Average Max Temperatures, Orange-San Diego Counties +3 +3 +1 -2 -2 +0.6

Average Min Temperatures, Orange-San Diego Counties +3 +2 +2 +3 -1 +1.8

Average Max Temperatures, So CA Inland Empire +2 +2 +1 -2 -4 -0.2

Average Min Temperatures, So CA Inland Empire +2 +1 +1 +2 -3 +0.6

NOTE: The predicted average max temperature anomalies are greater (negatively) than are the predicted average min temperature anomalies, especially Jan-Mar 2015. This is because of more frequent cloud cover, which will lower the daytime temperatures more than it will the overnight temperatures.

Philip K. Barone, with input from Charles B. Pyke, Ph.D., Meteorologist / Seasonal Outlook Specialist.

AWH FORM 63

 

 

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