Our weather widget pulls your location based off of what your ISP returns for the city and state name. Sometimes this information is incorrect and in those cases we allow you to set a custom 5-digit ZIP code. Please enter your zip code below.

Winter Seasonal Text Alerts and forum
MPM subscriptions are now available
Click to subscribe!

Long Range Outlook

Important information:

  • Eastern PA Weather Authority is no longer, and we have changed the business name to EPAWA Weather Consulting, LLC as of October 26th, 2018. Same great products, both free and paid, just a new name that better reflects what we do as the business of EPAWA.
  • Ongoing discussions and comprehensive model analysis ahead of any storm threat is conducted exclusively in the EPAWA Premium Forum, and not publicly until a threat is imminent. To become part of the advanced discussion, and to get long range updates on Mondays and Wednesdays in addition to this Friday public update, visit http://epawaweather.com/my-pocket-meteorologist/ and select “Premium Weather Forum”.
  • The EPAWA app is available and is completely FREE and does not require a download from the app store. This is a progressive web app that replaced the old app in December 2017. From a mobile device, simply open your browser and go to https://m.epawaweather.com/ and be sure to accept notifications and allow the app to detect your location for full functionality of the app. You then have the ability to save the PWA to your home screen, and it will work similar to a native app.
  • Winter-only text alerts and premium forum options for the 2018-2019 Winter are now available for purchase. A nominal one-time fee will bring you detailed alerts throughout the Winter between November 1st, 2018, and March 31st, 2019, or last snowfall. Visit http://epawaweather.com/winter-weather-alerts/ for full details and sign up.
Screenshot (1)
DatesThreatsSignificanceConfidence
1/20-1/22TemperatureWell below averageVery high
1/23-1/24TemperatureSlightly above to above averageHigh
1/25TemperatureSlightly below averageHigh
1/26-2/3TemperatureBelow to well below averageHigh
2/4-2/10TemperatureBelow to well below averageModerately high
2/11-2/17TemperatureSlightly below averageModerate
1/19-1/20Snow/ice/rainA large and impactful system will bring heavy snow to the interior, snow to mix to rain in the middle, and heavy rain for SE areas. This is our current system that will wrap up Sunday morning, then a flash freeze and windy conditions follow behind this system.Very high
1/23-1/24RainA cold front will bring rain showers to the region on Wednesday, and then get hung up over our region on Wednesday night/Thursday and not completely push through. Low pressure will form along the boundary and move northeastward along it, bringing periods of rain, some heavy possible Wednesday night/Thursday. This is the actual "pattern changing storm"High
1/27-1/28Winter Storm SignalModels are indicating a clipper system moving through the Great Lakes at this time with possible redevelopment off the coast. If no redevelopment, this is a light snow event. If the redevelopment occurs, it could be much larger. This one is post pattern change, and snow.Moderately high
1/24Pattern changeSustainable pattern change date is January 24th, and that is still on track behind the late week system. Beyond this date we will see more sustainable cold and active winter storm threats.Very high
January as a wholeTemperaturesSlightly above average (+1.0°F to +3.0°F)High
January as a wholePrecipitationNear average (-1.0" to +1.0")High
January as a wholeSnowfallNear average (end of month)Moderately high
February as a wholeTemperaturesWell below average (-5.0°F to -9.0°F)Moderately high
February as a wholePrecipitationSlightly above average (+1.0" to +2.0")Moderately high
February as a wholeSnowfallWell above averageModerately high

Outlook table last updated: Saturday January 19th, 2:20pm. Next scheduled update: Friday January 25th.

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. More information/sign-up at: http://epawaweather.com/my-pocket-meteorologist/ 

*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:

DateAverage Hi/LoEPAWA projection
January 19th40°F/25°FSlightly below average
January 26th40°F/26°FBelow to well below average
February 2nd41°F/26°FBelow to well below average
February 9th42°F/27°FBelow to well below 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.

Long range analysis: 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 rain or severe events, not publicly. To join this discussion and hear our updated thoughts from our team, visit The My Pocket Meteorologist Page by clicking HERE and select the “Premium Weather Forum” option.

Precipitation Discussion:

Precipitation:

We will see the active precipitation pattern continue through the end of the month. The first system we’ll be dealing with will move in Saturday late afternoon/evening and continue into the overnight period, and into Sunday morning. This is a far interior heavy snow, a snow to mix to rain situation in the middle, and heavy rain farther SE. For the latest map/call regarding this system, please visit the Weather Alerts page by clicking here:  http://epawaweather.com/weather-alerts/.

The next system comes in early next week, and is tied to a frontal boundary moving through on Wednesday. Rain showers are expected for all areas with the front, then most modeling hangs up the front and stalls it over the region on Wednesday night as it runs into ridging to the east and southeast. A low pressure center will form along that boundary and move northeastward, bringing periods of rain most likely Wednesday night and Thursday, and some could be heavy. This is the true pattern changing storm, and sustainable cold air locks in afterwards through February with no transient warm-ups in between. There is a chance the front is a bit more progressive and a wintry aspect will be brought into the equation, but odds are against that happening at this time. We will monitor it closely.

Another system looks to affect the region next weekend, but it is too early to speculate on that one to closely. Models are showing a clipper system moving through the Great Lakes, and then some show possible redevelopment near the coast. If no redevelopment occurs, this is a light snow event. If it does redevelop, it could be a much larger system. Regardless of evolution, this time period is outlined as the next winter storm signal, and will be snow as the precipitation type. We will revisit this one next week in daily local forecasts and forecast videos. Further storm signals are expected in early February, and we will outline those next week.

Follow our social media channels for updates:

EPAWA Facebook:  https://www.facebook.com/epawawx/

Meteorologist Bobby Martrich [EPAWA] on Twitter:  https://twitter.com/epawawx

YouTube channel/daily forecast video: https://www.youtube.com/user/eastpaweather

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

January 21st-January 27th: Slightly above to above average

January 28th-February 3rd: Near average

February 4th-February 10th: Near average

February 11th-February 17th: Near to slightly above average

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

 

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

The latest HRRR 3km simulated radar at 11:00pm Saturday shows heavy snow in the northern interior, changing to ice in the central areas, and rain farther south. The ice/rain line continues to move northward in the overnight.

hrrr

A storm that will likely usher in the long-awaited pattern change is due to arrive this Friday. Unfortunately for snow lovers, this one is rain for most before the change. But there are several winter storms in the pipeline.

gfs1

Pattern Discussion:

Pattern:

The Madden-Julian Oscillation (MJO): The Madden-Julian Oscillation is currently in the phase 4 octant, and the best forcing is expected to move through phases 5 and 6 thereafter. Beyond an extensive time spent in the circle of death. Stratospheric warming and a change in wind direction from west to east in the stratosphere occurred near New Year’s Eve, and the well-advertised subsequent stratospheric vortex split is observed as doing such. Strong stratospheric warming episodes disrupt the Polar Vortex (PV) away from the polar regions, and displaces the cold air farther south to lower latitudes. We do think we will see these changes and subsequent downwelling to the troposphere affecting our sensible weather beginning on January 20th briefly, then it relaxes and reloads on the 23rd/24th, then is here to stay thereafter. Stratospheric split vorticies that do successfully downwell to the troposphere will generally last 45-60 days from start, which takes us at least through the entire month of February. Once the pattern changes, it likely locks in for quite some time.

Through late Fall and early Winter, the pattern has been very similar to a Nov/Dec 2014 look, which featured colder than average in November 2014 (with a significant pre-Thanksgiving snow storm that year) followed by a mild and rainy December 2014. The mild bled into early January of 2015 before a flip into winter mode occurred, and the colder than average temperatures and above average snowfall followed through March 2015. We will not see this flip as early as we saw in January 2015, but do think we will see a turnaround this winter, beginning around January 24th.

Will we still see above average snowfall and make up for lost time? 

Yes, we still think so. We were never on the snowy December kick that some expected, and argued that December 2018 would mimic a December 2014 milder pattern. We also figured January would start off mild, then flip. While we were previously a few days early on that flip projection, it still will come. As such, with our expectations low for the early part of winter, our snowfall projections for an above average winter as a whole is still on track. Might be an active and wild 6-8 week period, but still winter nevertheless.

The January outlook is for a slightly above average month (+1.0°F to +3.0°F) as a whole with moderately high confidence. The milder start to the month will be offset somewhat once the pattern changes around the 20th of January, but with 2/3rds of the month prior remaining largely above average, the colder periods in the late month period will be difficult to completely offset the month as a whole. Our forecast for February suggests a well below average month (-5.0°F to -9.0°F) with well above average snowfall once the cold locks in from late January onward.

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

The GEFS show the transient milder period on the 23rd/24th prior to the pattern change expected on 1/24. Accompanying this milder period will be a pattern changing rain storm in the Wed. night/Thurs. period.

gefs2

This is the GEFS agree with our take that January 24th will be the pattern flip date. Cold air previously locked up in Canada is will settle over our region from Friday 1/25 onward, and remain in place through February.

gefs3

Next 3 weeks of US temperature departures

Images below are clickable for better viewing

Days 1-5 – confidence VERY HIGH

1-5

Days 6-10 – confidence HIGH

6-10

Days 11-15 – confidence MODERATELY HIGH

11-15

Days 16-20 – confidence MODERATE

16-20

Current 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.

My Pocket Meteorologist

The My Pocket Meteorologist text alert program is a year-round program, and seasonal options for Spring/Summer will be available soon. Click on the image below for more information.

mpm3

Forecaster: EPAWA Meteorologist Bobby Martrich
Discussion last updated:  Saturday January 19th, 2:50pm