Jan 9: Cold may stay around longer

Verification for Friday Night: My forecast was correct, with areas north and west of NYC seeing lows in the mid to upper 10s, and NYC’s lows in the lower 20s.

Today: Sunny. High temperatures will be in the lower to mid 20s north and west of NYC, and in the mid to upper 20s for NYC and closer to the coast.

Tonight: Clear. Very Cold. Low temperatures will be in the upper 0s to lower 10s north and west of NYC, and in the lower to mid 10s for NYC and closer to the coast.

Tomorrow: Mostly Sunny. High temperatures will be in the lower to mid 20s north and west of NYC, and in the mid to upper 20s for NYC and closer to the coast.

Tomorrow Night: Mostly Clear. Low temperatures will be in the lower to mid 10s north and west of NYC, and in the mid to upper 10s for NYC and closer to the coast.

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Early to mid week perhaps not as cold?

After what initially appeared to be a mild start to the week, the forecast models are holding the cold around longer. Monday will be slightly warmer than this weekend, with high temperatures in the upper 20s to lower 30s across the area. With what appeas to be a reinforcement of the cold on Tuesday, highs stay in the upper 20s to mid 30s. By Thursday, however, signs are that the cold will significantly weaken, and in return, warming will take place. On that day, the whole area should be over 30 degrees, and Friday will be slightly warmer. Areas near New York City should see high temperatures in the lower 40s on both days.

Cold spell for next weekend and storm?

After this brief 2-day stretch of mild temperatures, things turn colder. The GFS model has been consistent in showing an arctic outbreak by next weekend, focusing on New England. However, at the same time, we also have a moisture-loaded storm forming in the Gulf of Mexico. Below is what this morning’s GFS run (06z) showed:

Source of the 06z GFS model run: (The image above comes from the “850mb Temp, MSLP, 6hr Pcpn” section) http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/model_m.shtml

For those who don’t know how to read the map, the greens, blues and purples are showing precipitation, and anything north of the southernmost blue line typically represents temperatures below 32 degrees, and when the areas of precipitation are north of the southernmost blue line, that would typically mean snow or frozen precipitation.

What the models have nailed down is the formation of a storm in the western Gulf of Mexico by late next week or early next weekend. What happens afterwards is where the confusion happens. The model solutions have ranged from a storm tracking through the Ohio Valley bringing warmth and rain to the area, to a weak storm going far offshore with cold and dry conditions. However, the ensemble mean of the GFS model have been consistent for the past 4 days with the same solution, a storm tracking near the benchmark (benchmark is the name for the location of 40N/70W, which when storms pass near it, would typically mean snow for the cities from DC to Boston). This consistency is surprising, as it is very unusual to see an agreement with the ensembles this far out in the long range.

The current pattern shows a positive PNA (reflecting a western ridge, supportive for an East Coast storm), a negative NAO and a negative AO (but not as negative as now). These factors alone show that this storm has the potential to produce snow for the Mid-Atlantic and Northeast. However, we have had a few cases this winter, most notably the New Year’s Day storm and yesterday’s light snow, where the storm never lived up to its potential and became something smaller, or in other cases, the storm went too far offshore that it did not give us anything, or too far inland that it brought rain. So while this is still in the long range and a lot of things may change in the forecast, we need to keep an eye on this time period for a potential storm.

Long Range Pattern Update:

After next weekend’s storm, indications show that what happens afterwards may be a relief for those who do not like the cold and snow. The GFS model has been showing a significant warm up across the country after the 18-20th, and the end of the long range pattern outlooks also by this time period show the pattern turning into a -PNA (meaning trough and cold in the West Coast, which can mean a ridge and warm temperatures for the East), and a positive NAO and AO. While this is far in the long range and it may change, if this turns out to be correct, that would mean that by that time period, we may be seeing a warm up across the region to above average temperatures.

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