1/25/20 Verification

1/25/20 Climatology
Average high: 39F, Average low: 22F
Today’s Verification
Friday 1/24/20: High of 52F and Low of 25F. (+9F predicted vs 8F actual)
Last night, the temperature dropped suddenly to the mid-20s due to a lack of cloud cover and dry air. It was still above average, but not as above average as predicted. Similarly, during the day, the temperature rose 5F above what I had forecasted, nearly evening out my mistakes at both ends of the temperature spectrum. The models are clearly unable to resolve such high variability in temperature swings with a dry winter airmass and sunny skies.
A look at the next four days of temperatures at Rutgers Gardens:
Saturday 1/25/20: High of 52F and Low of 34F. (+10.5F); 1″ of rain 12 UTC – 20 UTC.
Sunday 1/26/20: High of 43F and Low of 33F. (+7.5F)
Monday 1/27/20: High of 44F and Low of 34F. (+8.5F)
Tuesday 1/26/20: High of 43F and Low of 31F. (+6F)



Verification 1/24/20 & Forecast 1/25/20

1/24/20 Climatology
Average high: 39F, Average low: 22F
Today’s Verification
Thursday 1/23/20: High of 47 and Low of 18F.(+3F predicted vs +2F actual )
Last night, temperatures dropped to 18F (-4F climo), below the 23F I predicted as a result of drier than expected air and less high clouds than anticipated. A similar trend continued into the day, allowing for the high temperature to reach 47F just before 20 UTC.

Screenshot from 2020-01-23 19-09-53.png

A look at the next four days of temperatures at Rutgers Gardens:
Friday 1/24/20: High of 47F and Low of 32F. (+9F)
Saturday 1/25/20: High of 47F and Low of 36F. (+10.5F); 1″ of rain 12 UTC – 20 UTC.
Sunday 1/26/20: High of 43F and Low of 33F. (+7.5F)
Monday 1/27/20: High of 44F and Low of 34F. (+8.5F)
Average of next four days: +8.8F

More detailed forecast? Continue reading

Forecast for 1/23/20

As a southerly component to the wind returned today, temperatures at Rutgers Gardens surpassed 40F again. Tonight will be the last night with temperatures threatening to drop below the average low temperature for the foreseeable future as the dewpoint rises into the 30s. Expect intermittent high cloud cover and a WSW wind to prevent the low temperature to drop as far as the RAP suggests (21F). The GFS is a high outlier at 29F and the NAM is around 24F-25F, which I tend to believe. Thus, expect a low around 23F tonight.

The sun will rise around 12:15 UTC and there will be intermittent clouds between 400 hPa and 250 hPa through the morning. The layer above 500 hPa will reach saturation by sunrise allowing for overcast conditions at night, overnight, and through Friday morning.

Pictured: NAM 00 UTC at F24 of simulated cloud cover throughout the entire column for 00 UTC on 1/24/20.

Screenshot from 2020-01-22 22-24-04.png

Expect temperatures to rise rapidly through warm air advection and plentifult solar radiation. By 15 UTC temperatures will rise above freezing and by 17 UTC temperatures will reach near 40F. Warm air advection will allow temperatures to crest near 43F at 19 UTC, with outlier model solutions hinting at the potential for 45F depending on cloud cover. My official forecast is for 43F as the high on 1/23/20.

1/23/20 Climatology
Average high: 39F, Average low: 22F

Today’s Verification
Wednesday 1/22/20: High of 41F and Low of 16F. (+0.0F predicted vs -2F actual )
A look at the next four days of temperatures at Rutgers Gardens:
Thursday 1/23/20: High of 44 and Low of 23F. (+3F)
Friday 1/24/20: High of 47F and Low of 32F. (+9.5F)
Saturday 1/25/20: High of 45F and Low of 36F. (+10.5F)
Sunday 1/26/20: High of 43F and Low of 34F. (+8.5F)
Average of next four days: +8F

Continue to read more about the coastal storm on Saturday. Continue reading

Forecast for 1/22/20

1/22/20 Climatology
Average high: 39F
Average low: 21F

Today’s Verification
Tuesday 1/21/20: High of 36F and Low of 15F. (-4F predicted vs -4.5F actual)
A look at the next four days at Rutgers Gardens:
Wednesday 1/22/20: High of 38F and Low of 22F. (+0.0F)
Thursday 1/23/20: High of 43 and Low of 26F. (+4F)
Friday 1/24/20: High of 46F and Low of 32F. (+7F)
Saturday 1/25/20: High of 44F and Low of 34F. (+9F)

The track of the coastal storm moving through the mid-Atlantic on Saturday is trending towards the north as time moves on, as indicated by the most recent GEFS member MSLP map:

Screenshot from 2020-01-21 22-21-13.png

Thus, the primary concern for most of Central Jersey is the amount of QPF over the course of Saturday.


Verification for 1/21/20

Overnight, Rutgers Gardens dipped down to 15F (!), slightly below the coldest model prediction, as a result of no cloud cover and weaker winds than expected. The temperature is currently 35F at 19 UTC, which is exactly as I forecasted yesterday. It’s likely that temperatures rise 1F further to 36F.

Screenshot from 2020-01-21 14-07-09.png

Because of this, today will end up to be -4.5F from the climatological mean, compared to the -4F that I forecasted. Clear skies continue for the afternoon but some cirrus clouds are streaming in from the northwest and will make an appearance later this evening. Precipitation changes still remain at <1% tonight, while temperatures should remain above 20F with light winds out of the west. Overall, a slightly below average winter day.


Forecast for 1/21/20 / Snow on 1/25/20

Rutgers Gardens could potentially reach its lowest temperature of 2020 (so far) with two models (the RAP and the NAM) simulating temperatures between 16F and 18F overnight into 1/21/20. The GFS is a warm outlier with temperatures hovering around 22F and more cloud cover than the other models, but given IR imagery and current observed cloud cover I tend to believe the higher resolution models, which indicate almost no cloud cover. Thusly, expect a low of 16F-18F (-5F to -3F) with a light NW wind below 5 mph. Winds remain light as the sun rises at 12:15 UTC and temperatures will climb past 25F by 14 UTC and into the 30s by early afternoon. With mostly clear skies during peak solar angle expect the temperature to be slightly higher than today’s high of 33F. I would expect a high temperature of 34-35F (-5F to -4F) at 19 UTC with a very light NW wind.

1/21/20 Climatology
Average high: 39F
Average low: 21F

The dewpoint will slowly rise from 10F to 15F over the course of the day, rising near 20F overnight into 1/22/20. Over the course of the next few days expect higher moisture returns as the airmass overhead changes character and warmer temperatures arrive. High pressure moves directly overhead New Jersey during the middle of the day on 1/21 which will guarantee clear skies and no precipitation. Chance of precipitation is less than 1% throughout the day.

Today’s Verification
Monday 1/20/20:  High of 33F and Low of 21F. (-3F actual vs -5F predicted)
A look at the next four days at Rutgers Gardens:
Tuesday 1/21/20: High of 35F and Low of 17F. (-4F)
Wednesday 1/22/20: High of 38F and Low of 23F. (+0.5F)
Thursday 1/23/20: High of 43 and Low of 26F. (+4F)
Friday 1/24/20: High of 44F and Low of 32F. (+7F)

Looking at the big picture for the next five days: anomalously warm conditions are likely to occur over much of Canada, the Western United States, the Great Lakes Region, and much of the Northeast, with unseasonably cool temperatures across the southeast during the next five days.

Screenshot from 2020-01-20 23-01-55.png

High pressure remains an inhibiting factor for precipitation in the northeast through Friday, when higher temperatures and increased moisture will begin to infiltrate the region as a result of an area of low pressure and upper level trough over the Ohio Valley. As the surface cyclone tracks along Ohio River, providing snow to northern Illinois, Indiana, and Ohio, it will bring precipitation to much of the Ohio River Valley on Friday into Saturday morning. At the surface, an area of low pressure will cross Virginia and Delaware and track into the Atlantic Ocean just south of New Jersey, providing parts of Northern New Jersey (NNJ) with the chance for wintry precipitation. The GFS is indicating a precipitation event with up to 1″ of QPF and up to 20″ of snow over interior New England. The 18 UTC GFS hints at the potential for a strong gradient of snowfall along the I-95 corridor, especially over New Jersey.

Screenshot from 2020-01-20 22-46-28.pngThese snowfall totals are highly sensitive to the track of the surface cyclone, which will guide the thermal gradients along the coast. North of the track of the surface low there will be significant amounts of rain and sleet mixing in, limiting snowfall. Given the first snowflakes would fall 108 hours in, expect changes in the strength and track of this surface cyclone, especially with the potential for convection to be associated with this storm as a front associated with it interacts with moisture in the Gulf of Mexico.

As of right now, the timing for this storm would be early morning on Saturday 1/25/20 and if this holds, thankfully impacts would be minimal compared to this storm impacting the northeast on Friday during rush hour. However, a shift in storm evolution of 12 hours is certainly possible. Using the GEFS ensembles, the consensus is clear for a surface cyclone to cross anywhere from NNJ to the Delaware Bay early morning Saturday. The average location in the GEFS is right over Delaware Bay, which would favor mostly rain along the I-95 corridor and likely a healthy amount of snow north of I-80 in New Jersey.

Screenshot from 2020-01-20 23-00-29.png

Expect updates on this potential snowstorm over the next few days.





The MJO and CONUS Weather

I came across the following plot on Twitter posted by @gensiniwx showing Outgoing Longwave Radiation (OLR) anomalies globally:


This plot indicates weakened convection over the eastern Indian Ocean, Maritime Continent, and parts of the Western Warm Pool (WWP). Alternatively, the Central Pacific Ocean and northeast towards Baja California is an area exhibiting an abnormally large amount of convective activity. This has implications for global weather patterns as it indicates that tropical and perhaps extratropical forcing is having an imprint on the midlatitudes through poleward propagating wave activity. Ths is an amplified phase of the MJO in phase 6/7.


What does this have to do with weather in the northeast? An old rule of thumb dictates that 2 weeks following a strong MJO phase 6, one can expect a drop in the NAO/AO and an increased probability for a strong trough over the eastern United States. If the thermal profiles are right, this phase of the MJO indicates an increased chance of unsettled weather and possibly snow over the eastern part of the US the week of 2/3-2/8.

The problem is, we will have to accomplish this without even a minor perturbation to the stratospheric or tropospheric polar vortex, which is extremely strong and shows no sign of breaking down. If we can get a weak shortwave that takes advantage of a brief period of high-latitude blocking triggered by extratropical wave forcing, that may just be enough. There is some indication of a weakening of the recent persistent +NAO based on ENSM forecasts. A glimmer of hope?

Screenshot from 2020-01-20 23-25-11.png


Verification for 1/20/20

Overnight, temperatures dropped to 21F at Rutgers Gardens (exactly as forecast!). This matches perfectly with the climatological mean as well. However, with completely clear skies and sunny conditions, the temperature has risen to 32F as of 19 UTC, well above my forecast of 30F. Temperatures can be expected to rise as high as 33F before dropping back down to 25F by 0 UTC.


As a result, today will end with a deviation of 3 to 4F below the climatological mean. Expect clear skies to continue, allowing temperatures to drop below 20F overnight.
Pictured: visible satellite view showing clear skies over the area, a remnant snowpack over northwestern New Jersey and much of Pennsylvania. Also shown are clouds formed from cold air passing over the relatively warm ocean.COD-GOES-East-local-New_Jersey.02.20200120.173113-over=map-bars=.gif Coupe

Forecast for 1/20/20

As dewpoints drop below 5F during the early morning hours of 1/20/20, temperatures will also drop near 20F in North Central Jersey (NCJ).

1/20/20 Climatology
Average high: 39F
Average low: 21F

Expect low temperatures for Monday to be around the climatological average but with a brisk NNW breeze from 10-15 mph, wind chills will be sub-10F during the morning hours. We are on the fringe of a massive, strong area of high pressure (1044 mb) over the central part of the United States:

As this high pressure slides east skies will remain mostly clear for most if not all of the day. Thus, expect sunny but cool conditions all day. The high is expected to approach 30F (-9F from average) as winds remain mostly northerly throughout the day. Averaged together, expect 1/20/20 to be approximately -5F from the climatological mean, but each subsequent day will be warmer as a southerly component to the wind returns on 1/23/20.

First look at the week ahead:

Date: High of XX and Low of YY. (Departure from climatological mean).
Monday 1/20/20:  High of 30F and Low of 21F. (-5F)
Tuesday 1/21/20: High of 34F and Low of 18F. (-4F)
Wednesday 1/22/20: High of 37F and Low of 24F. (+0.5F)
Thursday 1/23/20: High of 41 and Low of 26F. (+3F)

Very little chance of precipitation through 1/25 due to the influence of strong high pressure across the US.  As the high moves to the east on 1/23, a disturbance on the western flank of that high will advect moisture over the Gulf of Mexico, strengthening an area of low pressure over Texas which will move towards the north and east, bringing unsettled weather with some wintry precipitation to the eastern half of the country. At the upper levels this is aided by a 500 hPa trough and vorticity maxima that dips down from Canada on 1/23 and forms a cut-off low over the western Great Lakes region, moving right across the northern mid-Atlantic states. This has the potential to aid in surface cyclogenesis off the coast of New Jersey and is something to watch in terms of snow potential across interior New England and heavy rainfall along the immediate coast.