Colorado (and Interior Southwest) forecasts
- 1. Current status of the El Niño/Southern Oscillation (ENSO) phenomenon and prospects for the next six to nine months
- 2. Regional climate background information
- 3. Most recent Climate Prediction Center forecasts for May through September 2009
- 4. Most recent experimental forecast guidance for April through September 2009
- 5. Discussion of forecast guidance
- 6. Executive Summary
Outline for latest forecast webpage (updated on April 24th, 2009; next update by May 23rd, 2009)
This webpage consists of six parts:
1. Status and Outlook for ENSO (El Niño/Southern Oscillation), the most important global climate variability factor on year-to-year time scales;
2. Background information on regional climate variability of the interior western U.S;
3. "Official" CPC (Climate Prediction Center) forecasts for May through September 2009;
4. Experimental forecast guidance for April through September 2009 precipitation in the interior southwestern U.S.;
5. Discussion of experimental forecasts, and useful links to shorter-term forecasts;
6. Executive Summary of this webpage.
The most recent forecasts are based on observational data through March 2009. This website will remain online until further notice.
You are welcome to use any of the material from this website, but proper acknowledgment would be appreciated, especially when referring to figures, forecasts, and assessments unique to this website. PROPER ACKNOWLEDGMENT should state that the used material "was provided by Klaus Wolter at NOAA-ESRL PSD, Boulder, Colorado, from his website at http://www.cdc.noaa.gov/people/klaus.wolter/SWcasts/". The forecasts presented in section 4 are new and experimental - users are cautioned that no responsibility for any losses can be assumed by NOAA-ESRL PSD. For questions, contact me under (Klaus.Wolter@noaa.gov)
1. Current status of the El Niño/Southern Oscillation (ENSO) phenomenon and prospects for the next six to nine months
Recent sea surface temperature (SST) and wind conditions in the tropical Pacific from Australia to just west of South America show that negative SST anomalies of more than -0.5C have disappeared from the map, a drastic warmup compared to last month, even though weak negative equatorial SST anomalies persist from about the dateline eastward to 120W. At the same time, slightly enhanced tradewinds can be found all across the Pacific basin, so the near-neutral presentation of this map appears somewhat fragile. This figure is taken from the ( TAO/TRITON website) that is updated daily.
Since this figure reflects conditions over the last five days, the reader may be interested in an ENSO discussion that pays more attention to the longer time scales of this phenomenon. A monthly updated ENSO discussion provides for this by the end of the first week of each month, and features a comparison figure of similar ENSO situations near the end of that web site. The Multivariate ENSO Index (MEI) has continued below -0.5 for seven months now, and will take at least another month to reflect the apparent return of ENSO-neutral conditions.
Latest European coupled model forecast for central Pacific tropical SST anomalies. The so-called "anomaly plume" (a.k.a. "spaghetti plot") refers to fifty different forecasts that were computed during the last month from slightly perturbed initial conditions, in order to encompass the range of possible outcomes over the next six months. As the stippled blue line indicates, Nino3.4 SST have persisted below -0.5C from December through March, with an upward trend since January. The vast majority of this model's ensemble members (48 out of 50) show a switch to above 0C anomalies by June, consistent with itself since February. In fact, more than half of the ensemble members reach at least +0.5C by about August, indicating a potential transition to weak El Niño conditions. This figure is taken from the ( ECMWF seasonal forecast website) that is updated monthly around the 21st - just in time for this month's SWcasts update.
Latest comparison plot of 14 dynamical and 8 statistical model forecasts for central Pacific tropical SST anomalies. For those models that are run in ensemble mode (like the ECMWF forecast - note the one shown here is from LAST month, summarizing the information from March 2009), this graph shows the average outcome. The range of forecast outcomes appears to favor a gradual rise from the present cool conditions to near-neutral conditions by the middle of 2009. As noted before, statistical models appear to favor cooler conditions during the latter half of 2009 compared to the majority of dynamical models. In fact, there are seven dynamical (and NO statistical) models that project at least +0.5C later this year, while three statistical (and one dynamical) models predict the inverse situation either continuing into the summer, or reverting to it in the fall of 2009. The average difference between all dynamical and statistical models remains large (0.8C for the latter half of 2009), but not quite as large as last month's 1C. This figure is taken from the ( IRI ENSO model website) that is updated around the third Thursday of every month.
For an independent interpretation of the current situation, I recommend reading the latest NOAA ENSO Advisory which represents the official and most recent Climate Prediction Center opinion on this subject. The April 2009 CPC statement expects La Niña to transition to ENSO-neutral conditions during the month of April - mission accomplished!
2. Regional climate background information
Average timing of wettest three-month season during the course of the year is shown for just over 1,000 historical climate records in the interior Southwest. This figure includes both cooperative observing stations (mostly in the lower elevations) and automated SNOTEL sites (in the montane and subalpine regions of the Rocky Mountains). The number shown refers to the CENTRAL month of a three-month season (JAN=1, FEB=2,...,DEC=B). Note the spatial extent of the winter/early spring wet season (red numbers) over Colorado and points west: mostly at high elevations. By comparison, the summer monsoon season brings the most moisture to almost all of New Mexico and much of southern Colorado, southeastern Utah and eastern Arizona (blue numbers).
This companion map to the average seasonal wetness peak shows the average driest season during the course of the year. Note the lack of precipitation over eastern Colorado and New Mexico during the winter season, while Arizona experiences its driest season during late spring prior to the monsoon.
This map shows regions of similar precipitation variability for the Interior Southwestern U.S. for April through June, a season that requires nine core regions to describe the bulk of co-variability across the domain. COOP stations are indicated by circles, and SNOTEL sites by triangles. The amount of color in each station symbol represents the amount of local variance that is explained by the index time series created for each core region.
ditto for July through September, a season that requires ten core regions to describe the bulk of co-variability across the domain.
3. Most recent Climate Prediction Center forecasts for May through September 2009
The most recent U.S. government (CPC) temperature forecast for May 2009 shows a tilt of the odds towards warmer temperatures that covers almost all of our area of interest, with the exception of northeastern Colorado. This portion of the forecast matches both long-term trends and lingering La Niña impacts, even though the latter is discounted as an influence due to its rapid weakening over the last month, and anticipated 'distructive inteference' of an eastward moving intraseasonal disturbance ('Madden-Julian-Oscillation'). Above-normal temperature odds reach better than 50% over southern New Mexico - leaving the odds for below-normal at well under 20% for the same region. The precipitation forecast for May 2009 (below) is dry for all of Utah and most of western Colorado, although the tilt of the odds towards dryness is comparatively modest. Arizona and New Mexico are left uncommitted ("EC" = equal chances of above/near-normal/below normal conditions). A more typical La Niña-related outcome would be a dry spring for all of the southwestern U.S., but as mentioned above, La Niña was not considered a driving factor for this forecast. Both forecasts are taken from the monthly outlook website that is updated on the third Thursday of each month (as well as on the 1st of each month with an updated outlook).
From the related seasonal website, the next set of forecast maps shows the national CPC forecasts for July through September 2009. By that time-frame, La Niña is definitely not expected to play a major role anymore, so that long-term trends exert the strongest influence. In the case of temperatures, this leaves most of the Western U.S. with a slight tilt towards a warm late summer, including the western halves of Colorado and New Mexico, and all of Utah and Arizona. In the case of precipitation (2nd map below), the forecast map shows an unusually early commitment to an enhanced monsoon from eastern Arizona and most of New Mexico into western Colorado, based mostly on numerical model guidance. The remainder of our area of interest is left 'EC' for now, although a dry forecast over the Pacific Northwest clips the northwesternmost corner of Utah.
4. Most recent experimental forecast guidance - for April-June 2009 (last complete month of observed data used: March 2009)
The forecast guidance presented here is based on a screening stepwise multiple regression procedure that requires that each new predictor explains at least an additional 10% of the predictand's variance. These calculations were performed for the full record (1951/2-98/9), as well as for five subsets with a decade of data being withheld. The predictors I use include a variety of ENSO indices (including spatial differences and recent tendencies in time), regional SST averages in the Indian Ocean, Eastern Pacific and Caribbean, regional precipitation anomalies within the southwestern U.S., and a few general sea level pressure indices such as the North Atlantic Oscillation and centers of action both east and west of Australia.
For this go-around, I include calculations for the following targets (or predictands):
A. April-June 2008 precipitation for seasonal core regions 1 - 9.
B. July-September 2008 precipitation for seasonal core regions 1 - 10.
FORECAST TABLE:
First column is predictand (name of regional precipitation anomaly index);
2nd column is predicted standardized anomaly for the named region based on full training period (Water Years 1951-99);
3rd column is predicted standardized anomaly based on the median of the cross-validated forecasts (i.e., the middle of five predicted values;
4th column is the range of predicted values from all six forecasts;
5th column is Heidke Skill Score (HSS) for full training period (based on 3x3 contingency table using terciles - a score of 0 means that the forecasts are no better than what would be expected by change (one hit (correctly predicted tercile) out of three tries), a score of +100 would mean "perfect" forecasts (three hits out of three forecasts), and -50 would be the worst possible forecast skill (no hits at all); for a comprehensive discussion of forecast verification issues, I recommend this link , while a "light-weight" definition of this score can be found here.
6th column is HSS for all five cross-validated decades combined (independent verification);
7th column is the calibrated shift in the probability distribution towards positive or negative anomalies (upper or lower tercile);
8th column shows the change in the 7th column from last month, if applicable;
9th and last column shows a preliminary HSS for the last nine years (1999/2000-2007/2008); the number of forecasts with a tilt of at least 3% is indicated in brackets.
Note that the 7th column mimics the CPC forecast scheme in which the middle tercile category is left at 33.3% (unless otherwise indicated), and the upper and lower terciles add up to 66.7%, with the gain of the upper tercile meaning the loss of the lower tercile, and vice versa. If the data were normally distributed, and the skill in forecasting completely unbiased, a median predicted anomaly of +0.26 would translate into a shift in the terciles of +10%, with the lowest tercile being less likely than "normal" at 23.3%, while the highest tercile would be more likely at 43.3%.
See also the discussion section following this table.
PRECIPITATION FORECAST GUIDANCETIME-REGION PRED. ANOMALY PRED. HSS HSS CROSS-VALIDATED CHANGE FROM HSS PREDICTAND FULL MEDIAN RANGE FULL IND. TERCILE SHIFT PREVIOUS FORECAST 2000-2008
A1. AMJ-1=NW UT/SW W -1.0 -1.0 0.5* +34 +9 -13%* +/-0 +57*(7)
A2. AMJ-2=NW CO/Ctl UT -1.3 -.6 2.3# +22 +6 +/-0% +/-0 +17 (9)
A3. AMJ-3=SW UT -.2 -.2 1.6 +38 +16 0% -1% -13#(8)
A4. AMJ-4=most of AZ -.6 -.3 1.5 +28 +3 -1% -4% +25 (4)
A5. AMJ-5=SE AZ/S NM -.2 -.1 0.9 +34 +22 Neutral:+14%* Neutral:-15%# +25 (8)
A6. AMJ-6=NC NM+ 0.3 0.5 0.8 +41 +6 +15%* +1% -31#(8)
A7. AMJ-7=SW CO+ 0.3 0.2 1.1 +44 +22 -2% +/-0% +40*(5)
A8. AMJ-8=E CO Plains 0.7 0.0 1.5 +44 +3 +8% +/-0% +33*(9)
A9. AMJ-9=NE CO/SE WY+ -.4 -1.7 2.4# +19 +6 -6% +1% +10 (5) ==================================================================================================================
B1. JAS-1=NW UT -1.0 -.0 1.5 +34 +19 -2% / -7#(7)
B2. JAS-2=SE UT/NW CO -1.5 -1.4 2.3# +44 +9 -12%* / -17#(9)
B3. JAS-3=most of AZ -.6 -.3 0.9 +31 +6 -1% / 0#(6)
B4. JAS-4=SW NM 0.5 0.2 0.8 +22 +19 Neutral:+5% / +25 (8)
B5. JAS-5=NE NM/Sangres -.1 -.3 1.5 +31 +6 +3% / +6 (8)
B6. JAS-6=SE NM/NW TX 0.8 1.5 2.1# +44 +22 +13%* / -17#(9)
B7. JAS-7=NC NM/SC CO 0.4 0.8 1.7 +38 +3 +/-0% / 0#(0)
B8. JAS-8=SW/C CO (Mtn) 0.3 0.0 1.5 +34 +6 -3% / -20#(5)
B9. JAS-9=E CO (plains) 0.1 0.7 1.1 +41 +22 +6% / +6 (8)
B10.JAS-10=N Front Range 0.1 0.1 1.2 +31 +31* +8% / +17 (9)
I have marked with an asterisk (*) those forecast probability shifts that equal or exceed 11% (or, roughly, a doubled risk of one tercile category vs. the opposite one). The same applies to cross-validated as well as 1999-2008 verification Heidke skill scores above +30, as well as to predicted ranges of 0.5 or less. For AMJ'09, five out of nine predictions achieve this distinction, due to good verification skill (1,7,8), large probability shifts (1, 5, and 6), and predicted ranges below 0.5 (1). For JAS'09, three out of ten predictions reach this level, twice due to large probability shifts (2 and 6), and once thanks to a high cross-validated skill score (10).
In contrast, a pound (#) symbol indicates a very large spread (at least 2 standard deviations), weak cross-validated or 2000-08 HSS's (0 or less), or a large change from last month's forecast (more than 10%). Such forecasts should be taken with a 'grain of salt'. For AMJ'09, five out of nine predictands carry this stigma: two of them due to poor verification skill (3 and 6), two due to an excessive spread (2 and 9), and one due to a large change from last month (5), even though the latter reflects just a change in the probability of hitting the neutral tercile. For JAS'09, six predictands are flagged in this fashion, all due to poor verification skill scores (1,2,3,6,7, and 8). In addition, two predictands also feature excessive ranges (2 and 6). Sometimes, regional forecasts feature both symbols (* and #), which also reduces the confidence one should place in those forecasts. In this forecast round, AMJ'09 features two such 'mixed-message' forecasts (5,6), while JAS'09 does the same for predictands 2 and 6.
The forecast map below shows the calibrated shifts in the tercile probabilities for AMJ 2009:
Forecasted shifts in tercile probabilities for April-June 2009. In order to be shown on this map, a forecast tilt in the odds has to reach at least 3% either towards wet, dry, or near-normal. Shifts towards the wettest (driest) tercile are indicated in green (red), with a green plus sign for shifts between +3% and +5% (none), and a red minus sign for equivalent shifts towards the negative (none). Tilts towards near-normal are indicated by the letter "N", if at least by 3% (once). Question marks denote a forecast with a greater likelihood of being either wetter OR drier than near-normal at the expense of near-normal odds (once). Positive or negative shifts of over 5% are contoured in 5% increments. If any shift reaches over 10%, it is considered significant, even if recent verification skill has been wanting. There are three portions of the domain with significant tilts in the odds, one towards the wet tail of the distribution (northeast New Mexico), one towards the middle (southern New Mexico), and one towards the dry tail of the distribution (northern Utah). Unfortunately, only the dry forecast is supported by similarly high verification skill since 2000.
ditto for July-September 2009. This one has a question mark over north-central New Mexico/south-central Colorado, indicating a more likely outcome in the tails of the distribution than the middle, and one plus sign (in northeast New Mexico) and one minus sign (in southwest Colorado) each. Eastern Utah is covered by significant negatively tilted odds, while southeastern New Mexico features positively tilted odds in excess of 10%. A weaker tilt in the odds towards a neutral outcome covers southwestern New Mexico.
To access an archive of earlier public experimental forecasts and verifications, click on the season and lead-time of interest, once you get to the respective directory. Average Heidke Skill scores for each forecast season are listed here. Most of this archive is updated through the end of Water Year 2008.
5. Discussion of forecast guidance
To repeat from the beginning of this webpage: This forecast guidance is experimental, and should be used with caution. NOAA-ESRL PSD cannot assume any responsibility for losses incurred related to them.
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Discussion of final Spring (April-June 2009) forecast guidance:
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AMJ-1 (NW UT/SW WY) shows a significant tilt of the odds (-13%) towards dryness this spring, along with modest cross-validated skill (HSS-IND=+9), and the highest verification skill for this season: HSS'00-08=+57. In other words, cautious pessimism appears appropriate. This forecast is mostly unchanged from last month.
AMJ-2 (NW CO/Ctl UT) features the only undecided tilt of this go-around and season (forecast tilts for upper and lower tercile are higher than for the central tercile). Given the weak cross-validated (HSS-IND) and modest verification (HSS'00-08) skill levels (+6 and +17, respectively), climatological odds remain the safest bet.
AMJ-3 (SW UT) has decent historic cross-validated skill (+16), in support of a climatological forecast (no tilt in the odds at all!). Verification skill score is at -13 for this season, down from +25 last month. In other words, this region joins region 2 in having an "EC" (equal chances) forecast.
AMJ-4 (most of AZ) features a minor tilt in the odds (-1%), down from +3% last month, along with decent verification skill (HSS'00-08=+25), up from -7 last month, and poor cross-validated skill (+3). Since this region tends to get little moisture during the spring season, this forecast is mostly of academic interest, and is to be interpreted as climatological odds (higher than La Niña-related odds which would have favored a dry spring).
AMJ-5 (SE AZ/S NM) continues to show a strong preference for near-average moisture (at a 14% tilt, or a 47% chance of getting near-normal precipitation). This forecast is supported by decent cross-validated skill (+22), and similar verification skill (+17). Near-normal moisture continues to be the safest bet for this spring in this region.
AMJ-6 (NC NM+) features a significant positive tilt in the odds (+15%) towards a wet spring, by far the most optimistic forecast. However, while cross-validated skill levels are at least positive (+6), verification skill remains poor (-31). I would caution against expecting more than average moisture at best.
AMJ-7 (SW CO+) has a modest shift in the odds towards dryness (-2%), same as last month's. This is supported by decent verification skill (+22) as well as high cross-validated skill levels (+40). Since La Niña springs tend to be dry in this region, a dry outcome is indeed more likely than not, even though the tilt in the odds is small.
AMJ-8 (E CO Plains) continues to show an optimistic tilt in the odds towards a wet spring (+8%), but the cross-validated (+3) skill score is not very supportive. On the other hand, the verification skill score has risen to a very respectable +33 (compared to +14 last month). As I wrote in earlier discussions, a wet spring would be atypical in the wake of La Niña winters, but not unprecedented (an extremely wet April in 1999 was sufficient to bring about a wetter-than-average spring). With the luxury of hindsight, a wet April has indeed been observed in much of the region already, so this unusual forecast is off to a good start (note that the forecast uses input conditions through March 2009 only).
AMJ-9 (NE CO/SE WY+), just to the north of AMJ-8, shows a continued tilt towards dryness (-6%) after February's 'optimistic' tilt towards wetness (+10%). The forecast is supported by modest verification skill (+10), down from very high skill levels last month (+50). A wide range of ensemble members (2.4 standard deviations) cautions against too much confidence in this forecast, in addition to only a modest cross-validated skill score of +6. This is a region where spring is the wettest time of year, so the difference between a dry and a wet spring will have a large impact. Given a wet start to the season, it will take a dry May and June to yield a dry spring - possible, but maybe not as likely as the odds of this forecast suggest.
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Discussion of first Summer (July-September 2009) forecasts:
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JAS-1=NW UT shows a slight tilt of the odds towards the dry side of the distribution (-2%), supported by decent cross- validated skill (+19), but not by the poor verification skill in nine previous summers (-7). Climatological odds are the safest bet for now.
JAS-2=SE UT/NW CO features a significant tilt of the odds towards the driest tercile (-12%), but cross-validated skill is only modest (HSS-I=+9), while the verification skill level has been poor (-17), and the spread of ensemble members is very large (2.3 standard deviations). Another case for climatological odds.
JAS-3=most of AZ has a minor tilt of the odds towards a dry monsoon season (-1%), along with modest cross-validated (+6), but poor verification (0) forecast skill. This is the only forecast region with a known tendency for wet monsoons during La Niña conditions, and its dry winters also tend to be followed by a wet summer. Since this winter was indeed mostly dry, the latter tendency comes into play in contrast with last year. All in all, climatological odds are the safest bet for now, but it will be interesting to monitor this (difficult) forecast region and season over the next few months.
JAS-4=SW NM features the only near-normal forecast (Neutral:+5%) for this season. Skill levels have been decent this far out in the cross-validated sense (+19), as well as in the verification sense (+25, highest of this forecast round for the summer). This is a region where forecast skill levels increase significantly as we get closer to the summer, but for now, a near-normal outcome is the safest bet.
JAS-5=NE NM/Sangres shows a positive tilt in its foreast (+3%), supported by only limited cross-validated and verification skill (HSS-I=HSS'00-'08=+6). Too early to depart from climatological odds.
JAS-6=SE NM/NW TX features the largest positive tilt in the precipitation odds for this season (+13%). This is backed up by decent cross-validated skill (+22), but contradicted by poor verification skill (-17), and a large range of forecast ensemble members (2.1 sigma). Another case for climatological odds despite the large forecast tilt.
JAS-7=NC NM/SC CO features one of those 'schizophrenic' situations where the tails of the distribution appear more likely than the middle, depicted as a question mark in the forecast map. This region is only poorly predictable, as shown by a cross-validated score of +3 and a verification score of "0". Bottomline: climatological odds!
JAS-8=SW/C CO (Mtn) has a modest tilt of -3%, along with modest cross-validated skill (+6) and poor verification skill (-20). Yet another case where climatological odds are most appropriate for now.
JAS-9=E CO (plains) features a moderate positive tilt in the forecast odds (+6%), supported by good cross-validated skill (+22), and only marginal verification skill (+6; at least this is improved over last year's value of -7 due to a correct forecast in 2008). Given that the neighboring region (10) also shows a positive tilt, a wetter-than-average summer appears more likely than not for the plains of eastern Colorado.
JAS-10=N Front Range is the only summer forecast region with significant cross-validated skill (+31), a fact which is somewhat supported by recent verified performance (+17). Since the forecast tilt is moderately high (+8%), I believe cautious optimism is warranted for this region as well.
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Links to further pertinent websites
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Given continued drought conditions in much of the western U.S., there is great concern about streamflow and reservoir levels. To help with the near-term assessment of precipitation prospects, I am enclosing a few links of interest:
1. Outgoing Longwave Radiation ( (OLR) anomalies for the last week) show up as blue for deep convection (over the tropics). Recent thunderstorm activity over the western tropical Pacific is flagged by this color, while suppressed cloudiness (yellow-orange) lingers over the central and eastern equatorial Pacific, as well as over the southwestern U.S. (in the wake of the big storm that hit northeast Colorado last weekend). Most of these feature still support lingering La Niña conditions.
2. Under the following link, click on "latest forecast", then on "precip" at the top (This link is based on work originated by Jeff Whitaker) and forecasts generated here at NOAA-ESRL PSD, with a recalibrated version of the Medium Range Forecast (MRF) model that was originally developed at NCEP. This forecast page has been irregular in its updates due to computing changes at NCEP where it is now being run. A related user-friendly link to "zoomed-in" forecasts is maintained by ( Gary Bates) who takes the recalibrated MRF forecasts and puts them into an interface where the user can pick and choose the grid box for which a daily temperature or precipitation forecast out to fifteen days is desired. This webpage has had similar issues with irregular recent updates.
6. Executive Summary (updated on April 24th, 2009; next update by May 23rd, 2009)
1. During the fall of 2008, weak-to-moderate La Niña conditions returned and influenced our weather right through the winter. The recent weakening of this event is quite similar to last year's. Beyond the middle of 2009, there is large uncertainty as to whether La Niña returns for yet another encore performance, or whether we will see a switch to El Niño.
2. The last four weeks have brought above-normal moisture to much of Colorado and northern Utah, including Colorado's Front Range in particular. While not quite the turn-around of March 2003, this has significantly improved drought conditions, leading to local flooding due to rapid meltoff this week instead of an early forest fire season. It also resulted in a significant late-season boost to snowpack values in Utah and Colorado. This weekend should see a resumption of unsettled and cooler weather for both states which will slow down and in some cases reverse this week's rapid meltoff conditions.
3. My experimental forecast guidance for the late spring season (April-June 2009) reflects both lingering La Niña impacts (a dry forecast from northern Utah into northernmost Colorado), as well as the possibility of a return to near-normal ENSO conditions which would allow for a wetter-than-average season from Arizona to northeastern New Mexico and northward into eastern Colorado. The eastern Colorado portion of this 'wet' forecast is now backed by higher forecast skill than before. A first look at the monsoon season (July-September 2009) is handicapped by poor skill this far out in much of the domain. Nevertheless, it is supportive of enhanced precipitation chances over eastern New Mexico and Colorado.
4. Bottomline: The tropical Pacific is on a similar track as last year's. As I wrote last month, even La Niña springs allow for occasional wet spells, in particular during April, while the season as a whole is more likely to end up on the dry side for much of the southwestern U.S. if we continue to see a lingering La Niña 'flavor' to our weather. Thus, recent wetness should not be taken as a clear indicator that La Niña is to be 'counted out' just yet. Nevertheless, the odds have improved since last month for an average or even wet spring (and summer) in eastern Colorado and New Mexico.
Questions about this webpage should be addressed to:
(Klaus.Wolter@noaa.gov),
(303) 497-6340.