More clouds than sun this weekend,
but becoming progressively milder Get The Forecast!

*Indications of above or below average temperatures in the table above are relative to what is considered “normal” using data collected over the long term for a particular date. This is collected and maintained by the National Climatic Data Center in conjunction with the National Weather Service actual data from previous years collected at official ASOS/climatology stations across our coverage area. Also note that as time moves forward into a different period as shown above, average temperatures for those dates will also change. See the example below using Philadelphia, PA as the climo station:

The departure from normal uses the average temperature for the date, averaging temps over 24 hours for any given location, using both high and low temperatures hourly during any particular day. This outlook determines warm vs. cool periods relative to normal temperatures.

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Precipitation:

The month of April will start off rather quietly, and despite the clouds dominating this week and week ahead on several occasions, quantitative precipitation amounts largely won’t be that impressive with each “event” through at the middle of the month. As such, we will likely see slightly below average precipitation during the first 15 days or so of April. Beyond that point during the 2nd half of April, precipitation is expected to pick up, and indications are that the wetter period will last through at least the first half of May.

The first precipitation chance within the outlook may occur late this weekend, but only results in a stray and insignificant shower, mainly in southern areas, along a weakening cold front later Sunday or Sunday evening. The next unsettled period will arrive midweek, as a quick-moving and weak area of low pressure crosses the region on Wednesday. Scattered light rain showers are possible with that wave, which will be quickly followed by a cold front on the lead of the next incoming trough on Thursday afternoon/evening, and more showers possible with that front.

The precipitation departure from average for the month of April we project will finish slightly above average (+0.5″ to +1.5″) with moderately high confidence, with the 2nd half of the month being anomalously wetter than the 1st half of the month. Early look at the month of May using a blend of ensembles, climate models, and seasonal trends suggests an above average (+1.0″ to +1.5″) precipitation departure for the month as a whole.

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Breakdown of precipitation departures from normal over the next several weeks:

April 6th-April 12th:  Slightly below average

April 13th-April 19th:  Near average

April 20th-April 26th:  Slightly above to above average

April 27th-May 3rd:  Slightly above average

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Note:  Any image in the outlook is clickable for larger viewing

Although not much, the NAM 3km at max range shows a stray shower possibility in a few spots generally mid to late Sunday afternoon ahead of a weakening cold front, which will press through the region Sunday evening.

The next system is expected to reach our area on Wednesday, and will provide periods of showers mainly during the day. The GFS progression shown here is more robust with precipitation than its ECMWF counterpart.

Pattern:

The Madden-Julian Oscillation (MJO): The Madden-Julian Oscillation is currently in phase 5, and is expected to move through the circle of death and reemerge in phase 8 and 1 thereafter. It is apparent that the month of April as a whole will be notably cooler relative to average (anomalously) compared to March and the previous few months, but its effects may not be realized to the common observer since climatological normal highs and lows are also increasing at the same time. More of a status quo beginning to Spring. There will be some cooler periods though as outlined in the chart above, in part as a result of this eastward propagating MJO wave.

Teleconnections are forecast over the next few weeks to feature a -NAO to start the period through early April, but most other teleconnections are near neutral. Cooler risks are present at times later in the 2nd week of April, and most of week 3, but within the next few weeks we’ll still see temperatures still climb well into the 50s for high temperatures in spite of those slightly below average periods. As average highs and lows continue to climb these periods are relative to the time of year we are talking about. During the month of April, even “slightly below average” won’t cut it for snow events, and none are expected at this time.

It is expected that during the 4th week of April, temperatures will rebound to at least near average if  not slightly above average, and that general trend continues into early May. Projections for the month of May are for temperatures to rebound to slightly above average levels by month’s end, but will be closer to average highs/lows to start.

The month of April we project we’ll likely finish with near to slightly above average temperatures (+0.0°F to +2.0°F) for the month as a whole, with moderately high confidence. Early look at the month of May we project slightly above average (+2.0° to +4.0°F) temperatures, using longer range climate ensembles and global observation trends, with the first half of the month remaining closer to average for the most part, and rebounding anomalously during the 2nd half of May.

Snowfall: None expected going forward

Note:  Any image in the outlook is clickable for larger viewing

The EPS and others shows the anomalous warmth most prominent to our west and southwest early to mid next week, but a piece of that will reach our area during that time with several mild 65-70°F days expected.

Cooler risks will start coming into play beyond Thursday of next week with the arrival of the next trough. This will lead to slightly cooler than average temperatures returning to the 50s for highs for an extended period afterwards.

Images below are clickable for better viewing

Days 1-5 – confidence VERY HIGH

Days 6-10 – confidence HIGH

Days 11-15 – confidence MODERATELY HIGH

Days 16-20 – confidence MODERATE

Below is a look at the latest Soil Moisture Anomaly for the Contiguous United States. This is used by NOAA/CPC for the purpose of drought monitoring and drought outlooks.

This image will automatically update daily.

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Forecaster: EPAWA Meteorologist Bobby Martrich
Discussion last updated: Friday April 3rd, 12:25pm