EPAWA's long range outlook is updated weekly every Friday morning before noon

Long range outlook last updated: Friday May 9th, 2025, 10:30 AM

Technical discussion is below for advanced readers:

Technical discussion below will feature two (2) subcategories: Precipitation, and Pattern Discussion. Storm possibilities will be discussed exclusively in the Premium Forum with intense model analysis leading up to any major snow, ice, or rain events, not publicly. To join this discussion and hear the updated thoughts from our team, visit The My Pocket Meteorologist Page by clicking HERE and select the "Premium Weather Forum" option.

Precipitation Discussion

OVERVIEW: The US drought monitor (photo toward the bottom of this outlook) has largely remained unchanged from the the previous week, but this data is delayed and does not include the beneficial rainfall seen across the region since the start of this month. The most notable areas of moderate to severe drought are found across NW and far Southern New Jersey through East Central and Southeast PA, and extending into Western and Central Maryland. This may seem a bit deceiving, since many of those most drought-stricken areas have received quite the surplus in rainfall to begin May, and in some cases like Allentown, PA... the total rainfall has already exceeded what they'd normally see in the entire month of May. For this reason, I fully expect the drought map will look much much different this time next week. At the same time, southeastern portions of our region largely missed out on this rainfall, and many of those areas are actually slightly below average month to date. We adjusted projections for May this week to a solidly above average (up to +3.0") precipitation departure in the interior, and a near average monthly precipitation anomaly in our southeastern areas given the aforementioned disparity. The month of June projections was maintained this week for a near to slightly above average (+0.0" to +1.0") precipitation departure for the month as a whole. 

Shorter term, an upper level low is working its way through the region today with periods of rain, but will be followed by a dry weekend and start to next week. Another system will move from the SE US slowly northeastward early next week, and may bring scattered showers to the parts of the region as early as Tuesday afternoon. The system will weaken overall as it spreads northeastward, but showers with it are likely to occur most notably Wednesday and Thursday of next week. A cold front will follow Friday evening or overnight with scattered showers ahead of the boundary, then another cold front will follow a few days later that will be on the lead of trough, and sets up the week behind it to be cooler than average.

The projection for the month of May was adjusted this week for a solidly above average (up to +3.0") precipitation departure for the month as a whole in the interior with some of those areas through May 9th already exceeding what they'd normally see in an entire month of May with the rest of the month still to go. Southeastern areas which are currently slightly below average month-to-date we expect will recover to near average precipitation by month's end. The month of June projections were maintained this week for a near to slightly above average (+0.0" to +1.0") precipitation departure, using longer term climate models as well as seasonal trends. 

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

May 10th - May 16th: Near to slightly above average

May 17th - May 23rd: Slightly above average

May 24th - May 31st: Near to slightly above average

June 1st - June 7th: Near to slightly above average

June 8th - June 14th: Near average

June 15th - June 21st: Near to slightly above average

Public/free available maps will be updated when a threat is imminent for significant weather on the weather alerts page throughout the year:  http://epawaweather.com/weather-alerts/

Note:  Any image below is clickable for larger viewing  

Pattern Discussion

OVERVIEW:  The month of May projections were slightly adjusted this week for a near to slightly above average (0.0°F to +2.0°F) temperature departure as a whole. To this point of May temperatures are largely above average over most of the region, it appears that temperatures will fluctuate between slightly above average periods and slightly below average periods, ultimately settling with near normal overall conditions from this point forward. Despite the temperature fluctuations, no notable warm or cool extreme periods are currently expected. The month of June projections were also slightly adjusted this week to a near average (-1.0°F to +1.0°F) temperature departure for the month as a whole, using long term climate guidance and seasonal/global observation trends. 

• The Madden-Julian Oscillation (MJO) is currently in the Circle of Death (COD) or NULL phase, and is largely expected to remain there through much of May and early June. Since tropical forcing is rather weak, it should favor more seasonable temperatures for the most part going forward, and less in the way of abrupt colder...or warmer extremes. This likely sets the pattern for May to be rather seasonable overall.
  
  
• A composite average of the SST departures in the ENSO regions places it in ENSO neutral territory, and the Climate Prediction Center (CPC) has officially acknowledged that change recently. Any lingering La Niña background effects will continue to wane as we move through May. The Niño 1+2 region (eastern Pacific) had been the warmest of the 4 ENSO regions, but all other regions are now between 0.0°C and +0.2°C and solidly in ENSO neutral territory. The expectation is for ENSO neutral to remain throughout the Summer months, which typically favors slightly above average temperatures in the June/July/August 3-month period. Near average precipitation is typical of June and July, with a historically wetter than average month of August during ENSO neutral Summers within the past decade. 

Average high temperatures are currently in the 71-73 °F range from north to south across our coverage region, which is about 2-3°F higher than at this point last week. Average high and low temperature increases will continue at about a 2.0°F gain per week throughout May and through the entirety of June. Any above or below average stretches listed in the outlook will be relative to seasonal norms at that time, and it is important to note that cooler/warmer periods will be relative to the time of year we are talking about. For example, the slightly above to above average temperatures listed for the May 15th-18h period generally features highs in the upper 70s to lower 80s, coming at a time when average highs are typically in the mid-70s. Use the average highs/lows chart below providing a point of reference and transparency for what average temperatures are at each corresponding location through July 1st.

The month of May projections were slightly adjusted this week for a near to slightly above average (0.0°F to +2.0°F) temperature departure as a whole, with temperature periods of slightly above average and slightly below average balancing out over the remainder of May after an above average start to the month The month of June projections were also slightly adjusted this week to a near average (-1.0°F to +1.0°F) temperature departure for the month as a whole, using long term climate guidance and global observation trends. 

Note:  Any image below is clickable for larger viewing

Long Range Outlook Table

Climatology

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.

Climate Prediction Center (CPC) Graphical Products

These products are from the NOAA Climate Prediction Center (CPC) and do not necessarily reflect the EPAWA forecast which is detailed above. All images below update automatically as the CPC releases new graphical products

U.S. Soil Moisture Anomaly

US drought monitor (NE US)