A FIRST LOOK AT WINTER 2019-20

GENERALLY THERE ARE 3 TYPES OF WINTER SEASONS IN THE EASTERN US SEVERE / PROLONGED WINTER NORMAL/ CLIMO WINTER MILD/ RAINY WINTER

SEVERE or PROLONGED WINTER COULD start early- say in Mid November, and last into March, or even early April, OR: Starts in early/mid DEC and goes full blast into early March, with few if any, mild intervals. Can feature periods of Near Normal temps for most of the winter with numerous, significant snow events. Can feature sustained below Normal temps for much of the winter, but with near Normal, or Below Normal snowfall. EXAMPLES are winter of 1976-77, 1977-78, 1995-96, 2002-03 , 2009-10, and 2013-14.

NORMAL / CLIMO WINTER Typically, begins in mid – December, but may hold off until around Xmas. Often features cycles or intervals where pattern favors cold, then mild or active, then quiet. This kind of winter usually features classic “January Thaw”, starts in early/mid DEC, and goes full blast into early March, with few if any mild intervals. Often there is an interval of 2-4 weeks, which features coldest temps, and/ or most of the seasonal snow activity. Often there may be an area/ sub region over eastern half of CONUS, that gets hit with significant snow several times, while other nearby areas are near misses. EXAMPLES are winter of 2017-18, 2014-15, 2010-11, and 1986-87.

MILD WINTER Most of the time, a MILD WINTER in the eastern CONUS will feature a late start, with no significant cold air outbreaks, until last week of December, or 1st week of January. Usually, features Below, or Much Below Normal snowfall for most of the eastern CONUS. Most days/weeks have Normal or Above Normal temperatures. Often, MILD WINTERS will feature a week or two of Much Above Normal temperatures. A MILD WINTER will often have no widespread, arctic outbreaks. Cold air masses will be common, but NOT a true “arctic outbreak”. EXAMPLES are winter of 1972-74, 2001-02, 2015-16, 2011-12.

ALL SEASONAL FORECASTING IS 1/3 SCIENCE 1/3 ART / INTUTION 1/3 GUESS

ALL SEASONAL FORECASTING IS BASED ON: Key set of ASSUMPTIONS about the atmosphere. Large scale hemispheric forces known as PATTERN DRIVERS such as: El Nino/La Nina PDO Weak sun cycle Autumn build up of snow cover QBO Sea surface temps Soil moisture

These PATTERN DRIVERS set up the KEY teleconnections (specific jet stream configurations) such as: + AO /-AO +EPO/-EPO +NAO/-NAO +TNH /-TNH +PNA/-PNA These KEY TELECONNECTIONS set up the weekly and daily weather features such as: Low pressure/High pressure Cold fronts /warm fronts Sustained warm/ cold spells

KEY ASSUMPTIONS HAVE RISKS CONSENSUS FORECAST SUMMER 2017, called for a Moderate El Nino Below / Much Below Normal Hurricane season Almost everyone had this forecast in APRIL / MAY 2017 **GROUP THINK **

THERE WAS NO EL NINO in SUMMER 2017

None of those 3 forecasts were even close to being accurate for Winter of 2018-19. TEMPS = Above / Much above Normal, in the SE third of Conus. Below/ Much Below Normal in the Upper Plains & Upper Midwest PRECIP : Very wet in all of the CONUS east of the Rockies with two areas of Much Above Normal: 1) Upper Plains/ Upper Midwest 2) Oh & TN valleys into VA NC

DEC 2018 very warm all areas JAN 2019 mild se US, cool Great lakes FEB 2019 very warm in all of se Conus, very cold in the Upper/ central Plains & western CONUS

THE INFORMATION PRESENTED HERE BY WxRisk THE INFORMATION PRESENTED HERE BY WxRisk.com IS NOT A FINAL FORECAST CALL IT INFORMED WINTER SPECULATION. The Assumptions/ Educated Guesses made here are JUST that. Between now and NOV 15, the data / models /info will change.

KEY ASSUMPTIONS ABOUT WINTER 2019-20 “PATTERN DRIVERS” NO El Nino – NEUTRAL conditions this autumn which will likely last through the winter months. Strong BLOCKING Patterns in the Jet stream that have existed for most of the summer in the Arctic regions, northern Canada, Eurasia, etc., will return for the winter. CURRENT, Long - term Soil Moisture seems to favor mean trough in the eastern U.S. Weakening negative QBO.

KEY ASSUMPTIONS ABOUT WINTER 2019-20 “PATTERN DRIVERS” EL NINO ? LA NINA? NEUTRAL ? ENSO REGION

This graph shows all ENSO events (El Nino/ La Nina) since 1950, and their intensity forecasts.

This table categorizes all ENSO events (El Nino/ La Nina) since 1950 and their intensity forecasts. 2018-19

The Weak El Nino that began last winter and lasted through the spring is over

Most of the various ENSO models' forecasts show “NEUTRAL” conditions for the Winter of 2019-20. But there is a small risk of WEAK EL Nino conditions in WINTER 2019-20

The last two runs of the ECMWF model ENSO forecast show POSSIBLE return of weak El Nino in November and December

These maps show TEMP anomalies for DEC, JAN, and FEB for “NEUTRAL”, “WEAK”, “MODERATE”, and STRONG EL Nino conditions

KEY ASSUMPTIONS ABOUT WINTER 2019-20 “PATTERN DRIVERS” BLOCKING PATTERNS IN THE JET STREAM What makes a SEVERE/ PROLONGED winter vs. a “normal” or “mild” is the amount of BLOCKING patterns. AMOUNT = Intensity / location / duration of Blocking weather late in the autumn and during all winter months.

Let's focus on two of the four main Teleconnections that dominate weather patterns in North America The NAO (North American Oscillation) helps determine if the overall pattern in central/ eastern US will have a RIDGE (warm dry) or a TROUGH (cold /sometimes stormy). It has 2 phases – POSITIVE and NEGATIVE. (There are several “variants” of the NAO). If you are in the eastern third of the CONUS and you “like” cold, snowy winters, you want to see the NAO stay in the Negative phase as often, and as long as possible.

The AO (Arctic Oscillation) is a Major Teleconnection feature that determines if the overall pattern in central/ eastern US will have a RIDGE (warm/dry) or a trough ( cold /stormy). It also determines where the mean storm track is located. (Midwest/East Coast/Off the East Coast). It has two phases: POSITIVE and NEGATIVE. If you are in the eastern third of the CONUS and you “like” cold, snowy winters, you want to see the AO stay in the Negative phase as often, and as strong as possible.

SUMMER OF 2018 As you can see BOTH the NAO and the AO CONSISTENLY ran strongly positive all summer long. The AO was mostly NEUTRAL 12/1/18- 2/1/18, THEN turned strongly positive. The NAO was consistently Positive all winter long.

WINTER 2018-19 As you can see BOTH the NAO and the AO CONSISTENLY ran close to the “ZERO” or the NEUTRAL line . The AO turned strong in mid FEB 2018, which was one of the reasons the winter ended early in the Eastern CONUS.

OK, BUT WHAT ABOUT SUMMER OF 2019??? As you can see BOTH the NAO and the AO CONSISTENLY ran strongly NEGATIVE all summer long. Does this mean that for the WINTER of 2019-2020, the NAO and the AO will CONSISTENLY run strongly NEGATIVE all winter long? Uncertain. All that can be said is that there seems to be SOME indication that the AO / NAO will run Negative at times.

KEY ASSUMPTIONS ABOUT WINTER 2019-20 “PATTERN DRIVERS” Soil Moisture Trends Just like in the Atlantic and Pacific oceans where large, long lasting pools of warm & cold SSTA (sea surface temperatures anomalies), can and DO affect long term climate patterns, large sustained areas of SATURATED/ DROUGHT areas can and DO affect weather patterns.

KEY ASSUMPTIONS ABOUT WINTER 2019-20 “PATTERN DRIVERS” Surface Moisture

This map from NASA shows short term SOIL MOISTURE from surface down to 3 feet. The DRYNESS in the southeast US is significant, but fairly Recent. IF this dryness were to last into NOV, it might alter the pattern by helping to anchor the RIDGE in the Jet stream over the se US/ SW Atlantic ocean.

KEY ASSUMPTIONS ABOUT WINTER 2019-20 “PATTERN DRIVERS” The QBO The QBO quasi-biennial oscillation (QBO) is high-level wind at the very top of the atmosphere (30 mb) above the Equator, that oscillates from East (negative QBO) to West ( Positive QBO) . A full cycle can take anywhere from 18 to 30 months . The strongest Positive values are usually around +15.00 or so, while the strongest Negative values will range -25.00 to -30.00. The QBO winds and the PHASE / direction work their way down into the lower levels and affect weather patterns. http://en.wikipedia.org/wiki/Quasi-biennial_oscillation LINK FOR ACTUAL QBO DATA http://www.esrl.noaa.gov/psd/data/correlation/qbo.data

So what? WHY is this QBO thing important? Strongly POSITIVE QBO values (+10+) correlate to Non-Blocking weather patterns in the Jet stream. STRONGLY Negative QBO values (-20 to -30) in the cold season Months = +AO and +NAO patterns. BUT, QBO values that are “Neutral to moderately negative” ( +5 to -15), seem to favor Blocking patterns in the Northern Hemisphere in the cold season months (Nov to March).

EXAMPLE 1 In the AUTUMN of 2017, the majority / CONSENUS forecasts for the Winter of 2017-18, called for a MILD winter with Above Normal Temps in the eastern US. WxRisk.com CORRECTLY forecasted a much colder winter than the CONSENUS forecast (and near normal snowfall for many). One of the keys in making that correct forecast was WxRisk’s use of the QBO values and TRENDS indicating that moderately negatively QBO values that hold at approximately the same intensity in DJFM, tend to favor cold winters in the eastern US (all other things being equal ). For the winter of 2017-2018, WxRisk.com forecasted that a Moderately Negative QBO would last through the winter. That turned out to be exactly correct.

EXAMPLE 2 In the SUMMER of 2018, the QBO values were tied for the MOST negatives (East) values of all time. June 2018: -28.45, July 2018: -29.10, and AUG 2018: -20.41. Going into AUTUMN of 2018, WxRisk.com assumed the QBO would rise at a steady pace and would be in the range of -5 to +5 for most of the winter of 2018-19. WHAT ACTUALLY HAPPENDED? The QBO shifted rapidly from -9.91 in Sept 2018, to -2.79 in Oct 2018, +3.3 in Nov 2018, +8.5 in Dec 2018 to +9 in Jan 2019. In other words, the QBO rose from near Neutral in the autumn of 2018, to nearly +10 in the winter of 2018-19. This is NOT what WxRisk.com expected and our WINTER 2018-19 forecast for a cold eastern US winter failed.

The QBO Data Table Goes Back to 1948 Negative numbers = QBO above the equator blowing from East to West. Positive Numbers= QBO above the equator blowing from West to East.

The TREND with the QBO for Dec, Jan, Feb, and March is for the QBO to drop steadily to 0.00 by Dec 2019, and -2 to -10 by Feb 2020.

Summary of Recent QBO Activity Summers that featured QBO values of +10 or higher. Autumns with steadily dropping QBO values. Autumns/ winters with either No El Nino or weak El Nino events in the autumn/ winter. QBO values for the winter 2019-20 predicted between 0 to -10.

Matching QBO Analogs QBO data since 1950 indicates eight years that match the above criteria . They were the summer and autumn of 1952, 1961, 1969, 1978, 1993, 2001, 2002, and 2004. Assuming the QBO of the summer and the autumn trends continue into the subsequent winters, we get the following possible winter analogs – the winters of: 1952-53 1961-62 1969-70 1978-79 1993-94 2001-02 2002-03 2004-05

Overall Winter Pattern Based on the Eight Specific QBO Analogs Yellow, Orange, Red colors = Positive anomalies (Ridges) with RED = very strong Positive anomalies (possible BLOCKING). Blue, Dark Blue, Purple with Negative anomalies with Darkest Purple = extreme trough (prolonged cold/ storminess). This is a map of the Upper air pattern/ anomalies for the WINTER (Dec/ Jan/ Feb) based on these previous QBO analogs WHAT DOES THIS MEAN?

The Eight QBO analogs indicate that the overall pattern for the Winter of 2019-20 feature strong blocking patterns in Greenland (-NAO), Below Normal heights in Canada, and near Neutral AO.

The Eight QBO analogs indicate that for central and eastern U. S The Eight QBO analogs indicate that for central and eastern U.S. the Winter of 2019-20 will feature seasonally cold temperatures, while central Canada could see much below normal temperatures.

The Eight QBO analogs for DEC indicate that the overall pattern in DEC 2019, could be very stormy in central & eastern US. There could be an extreme - NAO feature over Greenland (-NAO), and –AO. Also there could be a cross polar flow from Siberia into Western Canada. The Jet stream appears to be set well to the south. In short, the winter storm potential threat from this pattern, IF it verifies, could be HIGH.

These Eight January QBO analogs indicate that the overall pattern for the Jan 2020 could be close to a “ near normal” Jan pattern. Strong positive anomalies over Alaska (+EPO) and the Arctic region (-AO), and a weak Greenland block (-NAO) indicate a variable pattern. This pattern may favor more in the Upper Plains, Great Lakes, and new England.

These Eight Feb QBO analogs for Feb 2020, indicate that the overall pattern could be very stormy in the eastern third of the US. There could be an extreme -NAO feature in Greenland (-NAO), but the blocking in the Arctic doesn’t look strong (neutral AO). This pattern indicates there could be a cross polar flow from Siberia into western Canada. The mean trough could be in the NE US. The winter storm potential threat from this pattern, IF it verifies, could be MODERATE.

These eight March QBO analogs for Mar 2020 indicate that the overall pattern could be very stormy in the central and eastern third of the US. The analogs show an extreme -NAO feature in Greenland (-NAO), along with a strong blocking in the Arctic (-AO). Strong ridge in the West Coast bringing in cold air to central/ eastern US. The mean trough in central US could bring a cold, stormy March 2020.

SUMMARY The QBO analogs are a PROBABILITY and not a CERTAINTY. They are NOT linear. The QBO can proceed at a steady pace for a few months, then suddenly make these big leaps. The QBO can even reverse course, as it did in the summer and autumn of 2016. So, yes, the QBO **APPEARS** to be favorable for a colder than normal/ snowier than normal winter in the eastern US. BUT, still a long way to go, and the QBO must be closely monitored throughout the autumn.

KEY ASSUMPTIONS ABOUT WINTER 2019-20 “PATTERN DRIVERS” WEAK SOLAR CYCLE One of the relatively NEW fields in CLIMATE studies, both seasonal and long term, has to do with SOLAR ACTIVITY. The Sun has energy Peaks (Solar max) which features enhanced sunspot activity and valleys (Solar Min). These Solar Max and Solar Min have a direct impact on monthly/ seasonal weather trends and patterns in the northern Hemisphere. The building research in this field is getting a lot of science news attention both in hard core science journals and “softer” science magazine websites, etc.

From PHYS.ORG web site

From WEATHERWISE MAGAZINE

This Graph Shows Generalized Summary of Solar Activity From The Past 60+ years.

If we look at solar activity Max and Min over the last 12 years, we can see there was a solar Min in the winter of 2009-10. There were 2 significant or severe winters in the eastern US: 2009-10 and 2010-11. BUT, note that there IS going to be another solar MIN this coming winter of 2019-20 and possibly 2020-21.

During the times of SOLAR MAX, the Winter pattern seems to favor BLOCKING over N. Pacific/ Aleutian Islands. This places the mean trough along the West Cost/ Rockies and a ridge centered in the se US. This favors a cold/wet winter for the western US and the Plains, and a MILD eastern US winter with above normal temps and below normal snowfall.

During the times of SOLAR MIN the winter pattern seems to favor BLOCKING over Greenland and the Arctic regions. This places the mean trough in the eastern US, and a ridge in the West Coast of US/ Canada. This favors a stormy winter in the eastern US with Below Normal temps, while the western US is warm and dry.

If we break it down by month, the SOLAR MIN seems to enhance blocking patterns in JAN, FEB, and MARCH (not shown). This places the mean trough in the eastern US and a ridge along the West Coast of US/ Canada. This favors a stormy winter in the eastern US with Below Normal temps, while western US is warm and dry.

SUMMARY The winters of 2019-20, and 2020-21, will both feature SOLAR MINs, which have a strong correlation to enhance blocking patterns in the winter Months (-AO and – NAO). Given the historical consistency of the past 100+ years of data, it is hard to ignore the significance of SOLAR MINs for this upcoming winter. Of course, there are many other influences that can mitigate SOLAR MIN influences (moderate or strong El Nino or La Nina events, extreme QBO values, lack of OCT snow cover in Siberia, unusual SSTA in the north Pacific and or North Atlantic). For the winter of 2019-20, none of these other mitigating factors are developing, at least not so far. Thus, WxRisk’s view that Winter of 2019-20 in central/ eastern US will be either a normal winter or a severe one, heavily dependents on this SOLAR MIN phenomena.

Preliminary Risk Analysis Guide For Winter 2019-20

Preliminary Risk Analysis Guide For Winter 2019-20 MID ATLANTIC NEW ENGLAND

Preliminary Risk Analysis Guide For Winter 2019-20 UPPER SOUTH OHIO VALLEY

Preliminary Risk Analysis Guide For Winter 2019-20 MIDWEST