EPAWA's Long Range Outlook

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

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.

Long range outlook most recently updated Friday May 2nd, 10:30 AM

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  

A cold front will approach Saturday leading to late day and evening t-storms for mainly interior areas, then the front will stall over the region on Sunday with most of the day dry until mid-late afternoon 
An upper level low will close off over the Ohio Valley on Sunday and will sit and spin for a few days, and more persistent showers and periods of rain is likely to occur from late Sunday through late Tuesday

Pattern Discussion

OVERVIEW:  The month of May projections were maintained this week for a near average (-0.5ยฐF to +0.5ยฐF) 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 (+0.0ยฐF to +2.0ยฐF) 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 Niรฑa background effects are continuing to wane as we move into May. The Niรฑo 1+2 region (eastern Pacific) has been the warmest of the 4 ENSO regions, and is currently still the warmest at +0.2ยฐC, but all other regions are between 0.0ยฐC and -1.0ยฐC 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 ยฐF range from north to south across our coverage region, which is about 2-3ยฐF higher than at this point last week. Average high and low temperature increases will continue at about a 2.0ยฐF 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 (-0.5ยฐF to +0.5ยฐF) 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 (+0.0ยฐF to +2.0ยฐF) 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

Average temperatures over the next 6 weeks are shown above at our major climate sites throughout the region, with temperature averages increasing two degrees per week through the middle of June
In the wake of an upper level low this week, temperatures will be on either side of average for week two of the month, with the expectation of more of the same for much of the remainder of May

Long Range Outlook Table

 

Date(s)ThreatsSignificanceConfidence
5/3TemperatureAbove averageVery high
5/4TemperatureNear averageVery high
5/5-5/6TemperatureSlightly below averageHigh
5/7TemperatureSlightly above averageHigh
5/8-5/9TemperatureNear to slightly below averageModerately high
5/10-5/14TemperatureNear to slightly above averageModerately high
5/15-5/21TemperatureNear to slightly below averageModerate
5/22-5/31TemperatureNear averageModerately low
6/1-6/7TemperatureSlightly above averageLow 
6/8-6/15TemperatureNear to slightly above averageVery low
4/25-4/26Cold frontA slow-moving cold front gradually moves through Saturday night and stalls over the region on Sunday, and scattered PM and evening t-storms will be possible, with most activity found Saturday PMHigh
4/30Stalled upper level low influenceAn upper-level low (ULL) closes off over the Ohio Valley late Sunday through Tuesday, and numerous waves of showers and periods of rain are likely to wrap around the ULL Monday and Tuesday; significant rainfall is possible during this time periodModerately high
May as a wholeTemperatureNear average (-0.5ยฐF to +0.5ยฐF)Moderately high
May as a wholePrecipitationAbove average (+1.0" to +2.0")Moderately high
June as a wholeTemperatureNear to slightly above average (+0.0ยฐF to +2.0ยฐF)Moderate
June as a wholePrecipitationNear to slightly above average (0.0" to +1.0")Moderate

 

Long range outlook table last updated: Friday May 2nd, 10:30 AM. Next scheduled update: Friday May 9th.

This is a weekly updated public long range guidance product from EPAWA. For daily long range updates and more detailed updates M-F, please join the EPAWA forum.

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Climatology

Please note that as time moves forward into a different period as shown above, average temperatures for those dates will also change.  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.

See the example below using Philadelphia, PA as the climate station:

DateAverage Hi/Lo (ยฐF)Current EPAWA projection
May 3rd71ยฐF/50ยฐFAbove average
May 10th73ยฐF/52ยฐFNear to slightly above average
May 17th75ยฐF/55ยฐFNear to slightly below average
May 24th77ยฐF/57ยฐFNear average
May 31st79ยฐF/59ยฐFNear average
June 7th81ยฐF/61ยฐFSlightly above average
June 14th83ยฐF/64ยฐFNear to slightly above average

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

CPC 6-10 day temperature outlook
CPC 6-10 day precipitation outlook
CPC 8-14 day temperature outlook
CPC 8-14 day precipitation outlook
CPC weeks 3-4 temperature outlook
CPC weeks 3-4 precipitation outlook
CPC next 3 months temperature outlook
CPC next 3 months precipitation outlook

U.S. Soil Moisture Anomaly

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.

US drought monitor (NE US)

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Forecaster: EPAWA Meteorologist Bobby Martrich
Discussion last updated: Friday May 2nd, 2025 10:30 AM