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

Long range outlook last updated: Friday May 23rd, 2025, 10:00 AM

NEXT UPDATE WILL BE FRIDAY JUNE 6TH DUE TO FORECASTER VACATION

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 been steadily improving for the most drought-stricken areas due to copious amounts of rainfall throughout the month. However this outlook is behind in data reporting and doesn't include the entirety of rainfall received within the past week to 10 days, and therefore I fully expect the drought map will look much different this time next week. For now, there is still a moderate drought indicated in Berks and Southern Schuylkill, Western Chester, and much of York and Lancaster Counties in PA, as well as much of North-Central Maryland. The areas immediately surrounding those regions are listed as abnormally dry, but again, these areas we fully expect to improve given the recent rainfall that doesn't figure into this week's outlook. Much of the remainder of the region has been removed from the drought or abnormally dry designation. We adjusted projections for May this week to a solidly well above average (up to +6.0") precipitation departure in the interior, and an above average monthly precipitation anomaly in our southeastern areas. The month of June projections were 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, a system that affected our region in the mid to late week period is in process of pulling away, sans a remnant upper level low that will swing by to the north on Friday. After a mostly dry holiday weekend, the next system will arrive in the middle of next week via the Ohio Valley, and showers will be possible in the Wednesday-Thursday time frame. There are still uncertainties with both the precise timing and the extent of showers, with models disagreeing on both elements presently. A cold front is likely to follow at the end of the week, for now we are projecting Friday, but timing of this too can change throughout next week.

May's projection was adjusted this week for a well solidly above average (up to +6.0") precipitation departure for the month as a whole in the interior with some of those areas through May 23rd far exceeding what they'd normally see in an entire month...in some cases more than doubling normal May precipitation with the rest of the month still to go. Southeastern areas will also finish with at least an above average (+2.0") precipitation departure by month's end we project. 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 24th - May 31st: Near average

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

June 8th - June 14th: Near to slightly above average

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

June 22nd - June 28th: Slightly above average

June 29th - June 5th: 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

As an upper level low moves from W-E across NY State today, a few afternoon and early evening showers (instability showers) will be possible for a short time in some areas and arbitrarily placed

A midweek system will originate from the Ohio Valley and brings a showers threat in the midweek period, followed by a late week cold front. The extent and exact timing is still variable at this time.

Pattern Discussion

OVERVIEW: The month of May projections were slightly adjusted this week to a near average (-1.0°F to +1.0°F) temperature departure from average as a whole. To this point of May temperatures are very slightly above average over most of the region, it appears that the last week of the month will feature some slightly below average temperature periods, ultimately balancing the month as a whole to either side of average overall. The month of June projections were also also slightly adjusted 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 remain there or close to it through the remainder of May and first 3 weeks of 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 June to be rather seasonable overall after the notable cooler than average 2nd half of May is behind us.
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 about a month ago. Any lingering La Niña background effects will continue to wane as we move through the remainder of May. The Niño 1+2 region (eastern Pacific near Peru) is once again the warmest of the 4 ENSO regions at +0.5°C, but all other regions are now between -1.0°C and -2.0°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 to leaning slightly 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 74-76 °F range from north to south across our coverage region, which is about 2°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 below average temperatures listed for the May 26th-27th period generally features highs in the lower 70s, coming at a time when average highs are typically in the middle 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 to a near average (-1.0°F to +1.0°F) temperature departure as a whole, with temperature periods of slightly below average balancing out the warmer first half of the month over the remainder of May. The month of June projections were also slightly adjusted this week to 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

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 now through early July

Overall cooler than average temps will remain in place for much of the remainder of May, then more seasonable temperatures follow in early June with highs getting back into the 80s in the first week

Long Range Outlook Table

Date(s)	Threats	Significance	Confidence
5/24-5/25	Temperature	Below average	Very high
5/26-5/27	Temperature	Slightly below average	Very high
5/28	Temperature	Below average	High
5/29-5/30	Temperature	Near to slightly below average	Moderately high
5/31-6/3	Temperature	Near average	Moderately high
6/4-6/7	Temperature	Near to slightly above average	Moderate
6/8-6/14	Temperature	Near to slightly above average	Moderate
6/15-6/21	Temperature	Near to slightly above average	Moderately low
6/22-6/28	Temperature	Near average	Low
6/29-7/5	Temperature	Near average	Very low
5/28-5/29	Showers	Low pressure moves through the Ohio Valley and brings scattered showers in the Wednesday-Thursday time frame; precise timing and the extent of showers is still a bit uncertain at this time	Moderate
5/30	Cold front	A cold front moves through the region in this time frame with scattered showers/t-storms possible	Moderate
May as a whole	Temperature	Near average (-1.0°F to +1.0°F)	High
May as a whole	Precipitation	Well above average, highest in the interior (+2.0" to +6.0")	High
June as a whole	Temperature	Near to slightly above average (+0.0°F to +2.0°F)	Moderately high
June as a whole	Precipitation	Near to slightly above average (0.0" to +1.0")	Moderate

Long range outlook table last updated: Friday May 23rd, 10:00 AM. Next scheduled update: Friday June 6th. No long range will be completed the week of May 30th due to forecaster vacation.

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

*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:

Date	Average Hi/Lo (°F)	Current EPAWA projection
May 24th	77°F/57°F	Below average
May 31st	79°F/59°F	Near average
June 7th	81°F/61°F	Near to slightly above average
June 14th	83°F/64°F	Near to slightly above average
June 21st	85°F/66°F	Near to slightly above average
June 28th	87°F/68°F	Near average
July 5th	88°F/69°F	Near average

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

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.