The forecast challenge is how fast the warm air will come up the east coast and change the snow to rain. If the cold air holds on at the surface, some of the rain will freeze on already-frigid surfaces.
From the Saturday morning NYC NWS office forecast discussion:
The NWS was expecting the highest amount of snow and freezing rain from NE NJ though the Hudson Valley into SW CT, but that axis is forecast further east now…..
GENERAL EXPECTATION IS A 1 TO 4 INCH SNOWFALL ACROSS NYC/LONG ISLAND WITH A GLAZE TO A FEW HUNDREDTHS OF AN INCH OF ICE...AND A 3-7 INCH SNOWFALL ELSEWHERE...HEAVIEST ACROSS INTERIOR PORTIONS OF S CT. ALSO OUTSIDE OF NYC AND LONG ISLAND...THERE WILL BE A BAND OF UP TO A TENTH OF AN INCH OF ICE IN A CORRIDOR RUNNING FROM NE NJ INTO SW CT...AND UP TO A GLAZE TO A FEW HUNDREDTHS OF AN INCH ICE ELSEWHERE...EXCEPT FOR ORANGE COUNTY...WHICH LOOKS TO REMAIN ONLY SNOW AT THIS TIME.
The storm ends rapidly with the passage of a cold front whipped around the storm, midday Sunday.
ANOTHER THEME IN THE 00Z [7pm Friday computer model forecasts ] SOLUTIONS...ONE THAT BUILDS IN THE TRENDS FROM LAST NIGHT...IS THAT THE PRECIPITATION SHOULD COME TO AN END FAIRLY RAPIDLY ON SUNDAY FROM NW TO SE...BASED ON A FASTER TIMING OF THE COLD FRONT MOVING THROUGH.
Then more deep freeze for the northeast, followed by a storm passing off the eastern seaboard Tuesday night/Wednesday.
The computer models are moving the storm further away from the east coast with each run, but recently….
TUESDAY NIGHT INTO WEDNESDAY...LARGE DIFFERENCES REMAIN AMONGST THE GLOBAL MODELS. THE GFS REMAINS WELL OFFSHORE BUT THE 12Z/20 EC PASSES JUST OUTSIDE THE BENCHMARK WITH AN INVERTED TROUGH AFFECTING THE REGION. 00Z/21 EC HAS TRENDED TOWARDS THE GFS...BUT AT THIS POINT DO NOT WANT TO MAKE HUGE CHANGES TO THE FORECAST SINCE THIS SCENARIO HAS BEEN OCCURRING ALL WINTER WHERE A COASTAL LOW SHIFTS OFFSHORE AND THEN COMES BACK A FEW RUNS LATER DUE TO THE DIFFICULTY THE MODELS HAVE WITH PHASING NORTHERN AND SOUTHERN STREAM ENERGY. THEREFORE...HAVE NOT MADE WHOLESALE CHANGES TO THE FORECAST AT THIS POINT. CHANCE SNOW REMAINS TUE NIGHT THROUGH WED AS AN ALBERTA CLIPPER PASSES NORTH OF THE AREA AND A SHORT WAVE PASSES SOUTH OF THE AREA. STAY TUNED.
Friday evening….. Freezing cold! Hands hurt so much I only lasted 35 minutes outside, and it’s hard to work a camera in gloves at 13 degrees and a wind, but not using the gloves was out of the question.
But the very thin moon was close to brilliant Venus and much dimmer Mars. And when we look closer at the photos, there are more surprises.
The earthshine on the moon was wonderful, but click on the photo to see it full size and look for details – near the bright limb of the moon is a star that the moon eclipsed just a few minutes before this photo was taken. Look at the south pole (lower left) of the moon and the white dot – a lunar mountain top standing up into the rising sun on the moon. Up in the sunlight, it might be a good location for solar collectors for a lunar colony some day.
Here’s a slightly longer exposure showing the sunlit lunar mountain and the star near the moon.
Here’s a view showing how the gathering of the planets looked in the western sky…. at this exposure, the color difference between bluer Venus and reddish Mars is easier to see.
Not until at least after next Wednesday.
From the National Weather Service, NYC office’s forecast discussion
THE BIGGEST ISSUE TO DEAL WITH OVER THIS TIME-FRAME WILL BE THE VERY COLD TEMPERATURES...WITH TEMPERATURES EXPECTED TO RANGE FROM 15 TO 25 DEGREES BELOW NORMAL FROM FRIDAY THROUGH MONDAY. DURING THIS TIME...EVEN THE WARMER AREAS IN AND AROUND NEW YORK CITY WILL STRUGGLE TO REACH 20 DEGREES AND OVERNIGHT LOWS WILL LIKELY DIP INTO THE SINGLE DIGITS EACH NIGHT OVER THE WEEKEND IN THE CITY...AND LIKELY DROP TO AT OR BELOW ZERO OUTSIDE OF THE CITY. THIS... COMBINED WITH PREDOMINANTLY WINDY CONDITIONS WILL RESULT IN DANGEROUSLY COLD WIND CHILLS BOTH SATURDAY AND SUNDAY NIGHTS...WITH WIND CHILLS OF 10 TO 20 BELOW ZERO.
THERE WILL BE THREE CHANCES FOR SNOW DURING THIS TIME. THE FIRST WILL BE THURSDAY AND THURSDAY NIGHT WITH A CLIPPER TYPE SYSTEM. THE LOW QUICKLY INTENSIFIES OFF THE COAST THURSDAY NIGHT... BUT....KEEPS THE HEAVIER PRECIPITATION OFF TO OUR EAST. EXPECT 1-2 INCHES ACROSS WESTERN SECTIONS AND 2-4 EAST WHERE THEY COULD REMAIN ON THE EDGE OF THE PRECIPITATION SHIELD A BIT LONGER. THE SECOND OPPORTUNITY WILL BE OVER THE WEEKEND...WITH ANOTHER CLIPPER TYPE SYSTEM THAT INTENSIFIES AS IT REACHES THE MID- ATLANTIC COAST...THIS SYSTEM WILL HAVE THE POTENTIAL TO BE A LITTLE MORE SUBSTANTIAL. THIS HAS THE POTENTIAL TO BE A MORE SIGNIFICANT SYSTEM FOR OUR AREA THAN THE ONE THURSDAY AND THURSDAY NIGHT. THE FINAL OPPORTUNITY WILL BE AT THE TAIL END OF THE FORECAST PERIOD NEXT TUESDAY. [warm air comes] UP ALONG THE EASTERN SEABOARD AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM ALONG THE GULF STATES. THIS WILL RESULT IN A WARMING TREND...BUT WE START OUT SO COLD THIS WEEKEND THAT IT WILL STILL BE COLD ENOUGH FOR SNOW AT THE ONSET.
Don’t ask….from the Boston NWS office….
.LONG TERM /THURSDAY THROUGH TUESDAY/... */ HIGHLIGHTS... - TEMPERATURES AVERAGING BELOW-NORMAL FOR MUCH OF THE FORECAST - WINTER STORM NUMBER 1: THURSDAY INTO FRIDAY - WINTER STORM NUMBER 2: SATURDAY INTO SUNDAY
What more could you ask for? (At least there’s a high amount of uncertainty about how bad these storms will be….so far.)
cue dramatic music
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For the NYC area, Monday’s storm will be more subtle than its other Monday cousins. Unless you are in Boston. Or you don’t have ice in your Monday morning commute.
There is less water in this storm for NYC and south, a snow equivalent of 5 to 8 inches and some of that will be in the form of ice pellets and freezing rain. We can get each of these forms of water during the Monday morning rush hour.
The masters of the weather forecasting models have noted the models agree on bringing cold air into the NYC metro area at ground level. That means whatever falls freezes as it falls through the surface layer. The variables in this storm are how much cold air comes in aloft and how fast the freezing rain turns to snow. (Although I’d rather have snow than freezing rain.)
This discussion is based on the 5pm National Weather Service forecast discussion and forecasts. Check the NWS or private forecaster for updates!
Good luck and be safe!
Thursday’s morning rush hour will be a bit slick as an inch or so of snow settles over the NYC metro area. Perhaps eastern Long Island will get more as a new storm develops well off shore. Inland, the highest amounts, such as they are, may be over the Hudson Valley, but the NWS is not guessing where the highest accumulations will occur – but no more than 2 to 3 inches.
The weekend features a stationary front that will drape itself from east to west to our south. The front will boost warm air up over us, and we’ll be cold enough for snow, on and off, during the weekend. Eventually one of the waves will strengthen offshore and move along the coast, perhaps continuing snow into Monday.
The amount of snow this weekend depends on how strong the high pressure system to our north is and how much it lets the front toward us or pushes it away from us. There’s enough moisture hanging around with this front to give an inch or so of rain, which would put out about 10 inches of snow, but over several days. If the high is weaker, the front could come further north and we could get more rain or ice pellets.
Watch the forecast for developments.
For the next few months, Jupiter will dominate the evening sky.
Jupiter will be obvious as it rises in the east after sunset. Any optical aid is useful to explore the planet more massive than all the other planets put together.
Binoculars will show up to four tiny dots, Jupiter’s four brightest moons, very near the dazzling disk of the planet. A telescope will help zoom in and increase the apparent brightness of the moons, as well as showing the atmospheric bands which have come and gone over the past decade. A larger scope will show the ‘Great Red Spot’ (more like the pale round spot, but still worth seeing) when it’s on the side of Jupiter facing Earth.
What will you discover at Jupiter for yourself?
PS: If you want directions to Jupiter, look next to the rising moon this week, especially at full moon, Tuesday the 3rd.
– Next, the planets low in the southwest sky after sunset are also worth following. We are attracted there by superbright Venus, brighter than Jupiter and will be a rival for our attention this spring.
And ‘worse’ might mean less snow.
But if you look at the map of snow totals, the NWS appears to be forecasting less snow than they did earlier today for coastal areas.
This is because the computer models used for forecasting have been more recently predicting the storm to track further north, allowing more warm air in above the ground. But the cold air, from the last few days and the snow still on the ground, is likely to keep the ground refrigerated. Forecasting the old-fashioned way, by looking at the data and analyzed maps, it’s too soon to make a good forecast. The NWS says the interaction between systems that will set the table for the storm will not be well defined until late Sunday, so we hope the models will continue to come into agreement on this storm’s track.
Watch for snow starting late Sunday night, which on Monday will change to rain will freeze on the ground for the areas nearest the coast. ‘Lucky’ people further inland will get 8 to 14 inches of snow, but less of the freezing rain. Southern Westchester County is forecast to ‘only’ get 6 to 8 inches, but that’s due to the rain mixing in, some of which could freeze solid while it rains or after it changes back to snow later Monday afternoon. Temperatures dropping to single digits for Tuesday morning will make whatever falls freeze.
The weather pattern for the rest of the week is still conducive for snow storms. The next chance later is the week. However, the latest model runs have the storm staying well out to sea.