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

Long range outlook last updated: Friday May 2nd, 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. 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. Although these areas have been shrinking a bit, it hasn't been enough to offset the rainfall deficits that have been largely common since the Fall of 2024. We adjusted projections for May this week to a solidly above average (+1.0" to +2.0") precipitation departure, and this is largely do to the projection of a stalled frontal boundary and upper level low influence through Tuesday of next week, with the bulk of the precipitation occurring between Sunday evening and end of day Tuesday. After that point, precipitation is generally near average. The month of June projections were introduced this week for a near to slightly above average (+0.0" to +1.0") precipitation departure for the month as a whole. 

Shorter term, a cold front will approach the region on Saturday, and after a dry start to the day, scattered PM and evening thunderstorms will be possible ahead of the boundary. That front will likely stall over the region on Sunday, and at the same time, an upper level low associated with a broader "Omega" blocking pattern will close off over the Ohio Valley. This upper level low will sit and spin in that area through Tuesday, leading to a more consistent and steady soaker from late Sunday or Sunday night through end of day Tuesday. During this time, 2-3" of rain can occur, with localized higher amounts possible. 

The projection for the month of May was adjusted this week for a solidly above average (+1.0" to +2.0") precipitation departure for the month as a whole, in large part due to the stalled frontal boundary expected over the weekend, and the closed upper level low influences that extend through early next week. The month of June projections were introduced 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 3rd - May 9th: Well above average

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

May 17th - May 23rd: Near average

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

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

June 8th - June 14th: 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 maintained this week for a near average (-0.5°F to +0.5°F) temperature departure as a whole. Although most of the month will be on brand and seasonal for May, it appears that temperatures will fluctuate between near to slightly above periods and near to slightly below average periods, ultimately settling with near normal overall conditions over the month as a whole. Aside from the early month synoptically-driven warm surge, no notable warm or cool extreme periods are currently expected. The month of June projections were introduced this week for a near to slightly above average (+0.0°F to +2.0°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 straddle the COD and phase 7 in the Western Pacific or general vicinity through much of May. 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 seasonable.
  
  
• 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 are continuing to wane as we move into May. The Niño 1+2 region (eastern Pacific) has been the warmest of the 4 ENSO regions, and is currently still the warmest at +0.2°C, but all other regions are between 0.0°C and -1.0°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 68-71 °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 the first half 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 near to slightly above average temperatures listed for May 10th-14th generally features highs in the mid-70s, coming at a time when average highs are typically in the lower 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 June 15th.

The month of May projections were maintained this week for a near average (-0.5°F to +0.5°F) temperature departure as a whole, with temperature periods of near to slightly below average and near to slightly above average balancing out throughout the month to near average by month's end. The month of June projections were introduced this week for a near to slightly above average (+0.0°F to +2.0°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)