Monthly Archives: May 2021

NYC Memorial Day Weekend Weather – May 28, 2021

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Quite a different picture this weekend versus last weekend. Instead of summer like warmth, temperatures will be 10-20ºF below normal in the 50s-60s Saturday and Sunday. A series of slow moving coastal lows is the culprit, bringing much needed rain, and the most substantial rain since the beginning of the month. Memorial Day looks sunnier with temperatures climbing back towards normal in the 70s.

Rest of today – increasing clouds, high temperature in the mid-upper 60s. Rain begins to arrive towards the late afternoon and continues on right through the overnight hours. Overnight lows dropping to around 50ºF.

Weather Prediction Center surface forecast for 8 AM Saturday. A low pressure center moving from the Ohio Valley will elongate with a stationary front extending east-northeast offshore of the region. Waves of low pressure will the move along this boundary this weekend bringing multiple rounds of rain.

Saturday – windy, rainy, and raw, with temperatures only in the mid-50s, which is more typical of March than May. Persistent northeasterly onshore flow with a stationary front positioned south of the region and waves of low pressure moving along it will act to keep things cloudy and cool. Overnight lows again around the 50ºF mark with rain chances backing off but still possible.

Sunday – another low pressure moving along that stationary front will bring more chances for rain particularly early in the day. High temperatures slightly warmer in the low-60s. Overnight lows in the low-50s.

GFS model 1000-500 mb thickness and precipitation type for 11 AM Sunday. Another area of low pressure is depicted impacting the area.

Monday – the unsettled weather finally moves off with a return to sunnier weather. High temperatures Monday should hit the low-70s as a result. Overnight lows in the upper-50s.

NYC Weather Update – May 24, 2021

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Welcome relief from the heat today with high temperatures below normal in the 60s as cool, onshore flow sets up. The warmth returns by mid-week with highs again touching 90ºF by Wednesday. A strong thunderstorm is possible with a cold front passing through that day. Afterwards, temperatures cool but still reach above average highs in the low-80s on Thursday.

Rest of today – partly sunny with gradually increasing sun, high temperatures in the mid-60s with easterly and northeasterly winds shifting towards the southeast. Overnight lows in the mid-50s.

Weather Prediction Center surface analysis for valid 5AM Monday. Overnight, a cold front pushed southwest of the area, allowing for a much cooler air mass to take hold, with easterly onshore flow off the still as yet cold waters of the Atlantic.

Tuesday – warmer with high temperatures in the low-70s and partly sunny skies. Overnight lows in the mid-60s.

Wednesday – a warm front will pass through and put us in the warm sector of a strong low centered well to our north over Canada. Temperatures are expected to reach around the 90ºF in the city. Later in the day, as a cold front approaches, scattered but possibly strong thunderstorms could roll through. Overnight lows in the upper-60s.

GFS 850 mb temperature anomalies for Wednesday at 5PM. We are forecast to see +7ºC anomalies at this level of the atmosphere, corresponding to much above normal temperatures at the surface.

Thursday – skies clear out with high temperatures in the low-80s. Overnight lows around 60ºF.

Subtropical Storm Ana

Over the weekend, the first named storm of the 2021 Atlantic hurricane season, Subtropical Storm Ana, formed over the open waters of the Atlantic northeast of Bermuda. While the storm itself was never a threat to land, it does mark the seventh year in a row that a named storm formed ahead of the formal start of the hurricane season.

GOES satellite imagery showing the circulation of Subtropical Storm Ana

We can’t draw any conclusions from a single storm, but it is worth noting that nearly all major forecast sources including NOAA are calling for a season of above average hurricane activity.

NYC Weekend Weather – May 21, 2021

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A dramatic warm up in store this weekend with highs climbing into the mid-80s and the 90ºF mark. A couple of scattered chances for thunderstorms come with a weak shortwave Saturday and a cold front passing Sunday. This second front will cool things back to seasonable temperatures in the low-70s to start off next week. Yet another warm spell with 90s is taking shape for mid-week next week!

Rest of today – partly cloudy with high temperatures in the mid-upper 70s in the city as high pressure remains dominant, cooler at the coast with a sea breeze developing. Overnight lows in the low-60s.

GFS model 500 mb height and vorticity for Saturday at 8PM. A shortwave with attendant vorticity is visible across Southern New England stretching west-southwest into PA and OH.

Saturday – partly sunny with high temperatures in the mid-80s as a warm front pushes through. A chance for showers and thunderstorms mainly in the interior as a shortwave passes later in the day. Overnight lows quite warm, in the upper-60s, could break records for the warmest minimum temperatures for this day.

Sunday – mostly sunny with high temperatures warming to the 90ºF mark in the city, possibly warmer. Downsloping northwesterly flow should aid this warmup. An isolated shower or thunderstorm is possible later in the day with a weak cold front approaching. Overnight lows dropping to the low-60s.

GFS model 2-meter above ground temperature and 10-meter above ground temperature for 2 PM Sunday.

Monday – big difference in temperatures with high temperatures back in the low-70s behind the cold front passing on Sunday. Overnight lows in the mid-50s.