Tag Archives: zonal flow

NYC Weather Update – Jan 25, 2021

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A long duration but light impact winter weather event is forecast to hit Tuesday and Wednesday. Since last week, the track of this storm has shifted north, resulting in warmer air present near the coast. This will result in wintry mix and little to now accumulating snow. We miss out on a more potent storm later in the week which will move well offshore of the area. Temperatures throughout the period remain below normal in the mid-30s at best, with a reinforcing blast of cold air late in the week.

Rest of today – mostly sunny with high temperatures in the upper-30s. Clouds increasing overnight with low temperatures around 30ºF.

  • ECMWF forecast total accumulated snowfall valid 7AM Wednesday
  • GFS forecast total accumulated snowfall valid 7AM Wednesday

Tuesday – mostly cloudy with high temperatures in the mid-30s. Periods of light wintry mix/snow during the day as a couple of modest low pressure centers impact the area. Light accumulations expected, probably around half an inch. Overnight lows steady in the mid-30s with rain/snow mixing possible.

Wednesday – rain/snow mix possibly extending into Wednesday morning. High temperatures in the upper-30s. Any accumulated wintry precipitation should melt rather quickly. Overnight temperatures dropping into the low-30s.

GFS model surface precipitation and 1000-500 mb thickness for 7AM Thursday. A potent storm is seen exiting east well offshore from NYC.

Thursday – another low pressure, center, much stronger than the ones associated with the early week develops and tracks well south of us. High temperatures in the mid-30s. The main impact of this storm for us will be the stiff winds it produces as it continues to deepen and the pressure gradient around it tightens. These winds will also be from the northwest, bringing in a colder air mass. Overnight lows in the low-20s as a result.

NYC Weather Update – Jan 11, 2021

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It’s been two weeks now without any appreciable precipitation in NYC and this dry stretch continues this week. A mostly zonal flow regime aloft should provide for generally calm conditions, esp. given a lack of any meaningful supply of moisture. Temperatures should trend into mid-40s with warming westerly downsloping flow modifying the air mass, eventually transitioning to a mild southwest flow later in the week.

Rest of today – mostly cloud with highs in the low-40s. Overnight lows in the low-30s.

Weather Prediction Center surface forecast for 7AM Tuesday. High pressure to our southwest should help drive westerly winds our way.

Tuesday – mostly sunny with high temperatures in the low-40s. Overnight lows in the low-30s.

Wednesday – still mostly sunny with high pressure remaining in control. High temperatures in the mid-40s. Overnight temperatures dropping into the mid-30s.

GFS model 500 mb height and vorticity for 7AM Thursday. Generally flat, zonal flow is seen over our area. However, signs of a big change are visible to the west, over the Northern Plains.

Thursday – High temperatures in the mid-40s again with mostly sunny skies. Overnight lows in the mid-30s.

NYC Weekend Weather – Dec 20, 2019

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We’ll enjoy a prolonged period of calm weather that should take us through the week of Christmas. Temperatures should warm from below average in the 30s to above average near 50°F by the start of next week. The above average temperature trend looks like it will extend through the week. No white Christmas this year. I’ll be taking some time off and won’t have another update until closer to the new year unless something significant shapes up.

Rest of today – clear conditions with high temperatures already peaking around the low-30s. Overnight lows in the low-20s with an Arctic air mass still hanging around.

Weather Prediction Center surface forecast for 7AM Saturday

Saturday – the high pressure responsible for the cold, but calm and sunny conditions progresses east and return flow should start taking hold, with winds veering south later in the day. High temperatures should be similar to today in the low-30s. Overnight lows will be warmer than tonight in the upper-20s with milder westerly downsloping flow.

Sunday – high temperatures continue to climb into the mid-40s as more southwesterly flow takes hold. Overnight lows likewise continue a warming trend to about the freezing mark.

  • GFS model output for 500 mb vorticity, wind and heights valid 6AM Tuesday, showing a flat, zonal flow set up
  • Climate Prediction Center temperature outlook for December 25-29, calling for warmer than average temps over much of the Eastern US.

Monday – the warming continues with high temperatures forecast in the upper-40s to near 50°F. Overnight lows in the mid-30s.

Next week, it appears that we’ll be in a mostly zonal (flat westerly flow) regime at the upper-levels. That should help keep things calm and uneventful.