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As of the May 19th, 2017, release, Week 3-4 outlooks precipitation outlooks are experimental, whereas the temperature outlooks are operational. Both are issued Friday between 3pm & 4pm Eastern Time.
HOME> Outlook Maps> Week 3-4 Outlooks

Week 3-4 Outlooks
Valid: 09 Mar 2024 to 22 Mar 2024
Updated: 23 Feb 2024

Temperature Probability


Week 3-4 Outlooks - Temperature Probability
Precipitation Probability
(Experimental)


Week 3-4 Outlooks - Precipitation Probability

Click HERE for info about how to read Week 3-4 outlook maps

Prognostic Discussion for Week 3-4 Temperature and Experimental Precipitation Outlooks
NWS Climate Prediction Center College Park MD
300PM EST Fri Feb 23 2024

Week 3-4 Forecast Discussion Valid Sat Mar 09 2024-Fri Mar 22 2024

The Weeks 3-4 Temperature and Precipitation Outlooks are for the period of March 9-22, 2024. With February ending soon, It is interesting to look back at this past meteorological winter (December-February). El Niño's canonical teleconnection to surface temperature has thus far dominated in the averages over the contiguous U.S. (CONUS), with much above normal temperatures experienced in the north, centered over Upper Mississippi River Valley, and near normal temperatures across the southern half of CONUS. Precipitation anomalies are also somewhat canonical, with areas of Southern California, the Southwest, the Central Plains, the Southeast, and the Mid-Atlantic seaboard receiving above normal precipitation, while areas of the Northern Rockies and Great Lakes have received below normal precipitation. Despite the dominance of the El Niño teleconnection in the averages, subseasonal variability in the form of a major Arctic air outbreak during mid-January led to a notable departure of the aforementioned temperature and precipitation patterns. The quandary of this forecast, as was the case with most Week 3-4 outlooks this past winter, is to determine the likelihood of subseasonal variability disrupting the canonical El Niño teleconnection.

Currently, El Niño is waning, with Niño 3.4 sea surface temperature (SST) anomalies expected to fall (79% chance) to neutral conditions by April-June. The latest Niño 3.4 weekly departure is ~+1.5 degrees C. Thus, despite its weakening, El Niño will likely continue to be an important background driver on the extratropical atmosphere through March. Looking more broadly, SSTs are above normal over much of the Northern Hemisphere, which will act as an overall warming influence on the atmosphere for the foreseeable future through surface latent and sensible heat fluxes. Over land, significant negative snow cover extent anomalies are noted over CONUS and Eastern Europe whereas positive anomalies are currently observed in China.

The Madden-Julian Oscillation (MJO), as measured by the Real-time Multivariate MJO (RMM) indices, appears to be non-existent, with both RMM1 and RMM2 near zero. However, there is a strong likelihood that RMM1 has a significant positive bias, which is the result of the removal of the 120-day mean in calculation of the RMM indices. The 120-day mean includes a strong positive Indian Ocean Dipole event from this past fall which is no longer occurring. Thus, if the 120-day mean were retained, the indices would indicate that the MJO is currently propagating over the Western Hemisphere and Africa (phases 8 and 1). Hovmoller plots of velocity potential support this interpretation, as they reveal a propagating MJO with anomalous upper-level convergence centered near the Maritime Continent and upper level divergence near and to the east of the dateline, likely associated with El Niño. Surmising that the MJO is coherently propagating through phases 8 and 1 then onward to the Maritime Continent by Week 3, this would favor ridging over Western Canada, which is quite consistent with dynamical model guidance for the end of Week 2 into Weeks 3 and 4.

Another important forcing to consider for this outlook is the polar stratosphere. Two weak and brief SSWs have occurred this winter - one in mid-January and one last week. These events are largely being discounted as having an impact on the March 9-22 valid period, as there is little evidence and a great deal of uncertainty of coupling producing surface impacts in North America. However, the dynamical models are forecasting a third SSW to occur in early March. The probability of this event being of a larger magnitude and longer duration than the prior events is relatively high, although there remains a significant subset of ensemble members that show the zonal winds at 10-hPa will not reverse or only weakly reverse. Regardless, should the SSW occur, knowing when and where coupling will occur along with any impacts on surface sensible weather is highly unpredictable. If anything, coupling and surface impacts may be more likely to occur in Asia, where snow cover anomalies are positive.

The North Atlantic Oscillation (NAO) and Arctic Oscillations (AO) are both currently positive but are forecast to trend toward zero by the end of Week 2. The dynamical models continue to trend these indices downward through Week 3 and Week 4, as indicated by their 500-hPa height patterns. Interestingly, the NAO’s anomaly center is shifted southwestward from Greenland, which would be a major warm signal in the northeastern CONUS. The Pacific-North American (PNA) pattern is currently negative, and it is also forecast to trend toward neutral by the end of Week 2. The dynamical models show a considerable amount of spread in the PNA into Week 3 and 4.
The Weeks 3-4 Temperature and Precipitation Outlooks take into consideration the El Niño teleconnection, the MJO, the aforementioned extratropical teleconnections, and a blend of dynamical model guidance from the ECMWF, CFSv2, GEFSv12, and JMA. There is unusually high agreement in the height pattern depicted by the models with anomalous ridging centered over eastern Canada and weak troughing along the southern tier of CONUS. Most models agree on weak troughing in Alaska centered over western Alaska and the Aleutians. There is some disagreement in the Pacific basin itself, with the ECMWF and GEFSv12 featuring near neutral anomalies, whereas the CFSv2, JMA, and Canadian depict anomalous ridging south of the Aleutians. This disagreement was more pronounced during Week 4. Despite this discrepancy, the models were given equal-weighted consideration due to their strong agreement over North America itself.

Consistent with this pattern, below normal temperatures are favored over the Southwest with probabilities ranging from 50 to 60%. Most of the remainder of CONUS is favored to be above normal with the highest probabilities reaching 80 to 90% over the Upper Mississippi River Valley, Great Lakes, and Northeast. These high probabilities are supported by the exceptional model agreement in the area, the anticipated El Niño and MJO impacts on the pattern, the southwesterly displaced negative NAO, the lack of meaningful snow cover, and the exceptionally ice-free/warm Great Lakes. It should be noted that the probabilities for above normal temperatures over the Northwest and Southeast have been slightly lowered from model guidance due to uncertainty associated with the pattern in the Pacific basin and the potential for a negative Arctic Oscillation, respectively. Equal chances of above or below normal temperatures are favored in the Florida peninsula due to expected above normal precipitation (60 to 70% chance) and the fact that neighboring SSTs are below normal. A 50 to 60% chance of above normal precipitation is forecast from Southern California through the Great Plains, given the onshore Pacific flow and expected troughing with cyclonic flow. For the Great Lakes region, the lack of ice cover slightly tilts the odds (50 to 55%) toward above normal precipitation. Along the Gulf Coast and Eastern Seaboard, 50 to 70% chances of above normal precipitation are forecast. Odds are elevated over the Mid-Atlantic due to persistent anomalously easterly flow over the region, which is similar to the wet scenario that unfolded during this past December.

The agreement between the models and MJO teleconnection leads to high forecast confidence in the pattern over North America. However, some confidence is lost due to the risk of an SSW before the beginning of the valid period. Further, there is a strong indication that temperature anomalies in CONUS will cool from Week 2 to Week 3 and again from Week 3 to Week 4. However, since the anomalies are so high in Week 2, this cool down is largely anticipated to be toward more climatological values for mid-March during Week 4.

Alaska is forecast to have much below normal temperatures during Week 2, and this cold is forecast to persist, but weaken, into Week 3 with a notable warm-up occurring by Week 4. Given this transition, confidence in Alaska is relatively lower than CONUS with below normal temperatures favored in western Alaska and the Aleutians and above normal temperatures in southeastern Mainland Alaska and the Panhandle. With respect to precipitation, a 50 to 55% chance of above normal precipitation is forecast for the southern coast, where onshore flow is expected to occur. In northwestern Mainland Alaska, under the trough, below normal precipitation is favored.

For Hawaii, the multi-model ensemble from the Subseasonal Experiment (SubX) shows enhanced probabilities of above normal temperatures consistent with observed, slightly above normal SST anomalies. Above normal precipitation is favored across all the islands.








Temperature Precipitation
FCST FCST
Hilo A60 A55
Kahului A60 A55
Honolulu A60 A55
Lihue A60 A55


Forecaster: Cory Baggett

The next week 3-4 outlook will be issued on Friday, Mar 01, 2024

These outlooks are based on departures from the 1991-2020 base period

These are two category outlooks and differ from official current three category outlooks currently used for the monthly and seasonal forecasts.



The shading on the temperature map depicts the most favored category, either above-normal (A) or below-normal (B) with the solid lines giving the probability ( >50%) of this more likely category (above or below).

The shading on the precipitation map depicts the most favored category, either above-median (A) or below-median (B) with the solid lines giving the probability ( >50%) of this more likely category (above or below).

In areas where the likelihoods of 2-week mean temperatures and accumulated precipitation amounts are similar to climatological probabilities, equal chances (EC) is indicated.



As of May 19, 2017, the temperature outlook is operational, while the precipitation outlook is still experimental



An ASCII (w/ HTML markup tags) text version of the written forecast is available.

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