Feb 22, 2012: Warmth Continues Tomorrow

Forecast Highlights:

– Temperatures remain above 55 degrees tomorrow for most places
– Colder storm expected Friday; brief period of sleet inland?
– Gusty winds Friday night, gusts above 40 mph likely
– Chilly and dry weekend, warming up early next week


With a warmer air mass moving into the region, today ended up with warmer temperatures than those of yesterday, with partly to mostly cloudy skies and highs peaking in the mid 50s for most of the area along with some places reaching 57-58 degrees in the immediate NYC area.The latest radar to the left shows widespread showers to the southwest and northwest of the area. Most of the precipitation tonight will stay to the north and south of the area, with moderate rain towards central New Jersey and moderate snow in places such as Vermont, although isolated showers are still expected.

Temperatures will stay mild through tomorrow, although the storm for Friday is trending colder, and is expected to start as a cold rain for most of the area, maybe even mixing with sleet in the northern parts of the area. Temperatures will cool down behind the cold front with strong winds likely, although temperatures will warm back up again by next week.

Thursday and Friday: Stormy, But Differences With Temperatures

Tomorrow will be another mostly cloudy day for the area; although isolated showers are possible, most of the area will be dry. Temperatures are expected to be similar to those of today along with a west/WNW wind expected, with temperatures reaching the mid 50s for most places and upper 50s near NYC. Despite the Friday storm only 2 days away, there is still some slight uncertainty due to minor differences with the models regarding the storm.

Storm Precipitation: Today’s model guidance trended south, colder and slower with the storm, with the ECMWF solution, yesterday’s bold outlier, significantly backing out of its strong, amplified solution, although the latest ECM run is still likely catching up to the rest of the model guidance and therefore was not used for tonight’s forecast. Overall, the UKMET and CMC appear to best represent the latest trends with the expected set up with the NAM and GFS gradually trending colder, and for tonight’s discussion I used a NAM/CMC combination as guidance for the forecast.

The precipitation is expected to move into the area around 1-2 AM on Thursday night, at which time temperatures are expected to be in the lower to mid 30s in the interior areas (NW NJ/Orange county in NY), upper 30s to lower 40s in the immediate NYC area and Long Island, and mid 30s in southern CT. The 925mb and 850mb layers are expected to be cold enough at the start of the storm to allow for widespread snow and sleet in the southern Northeast and southern New England, although the southernmost extent of frozen precipitation is slightly uncertain; the GFS keeps the entire area with rain, while the NAM and the earlier CMC run today showing light snow/sleet accumulations in NW NJ, SE NY and southern Connecticut. The latest NAM run may have been a little too far south with the snow, and due to a warm layer aloft, I added a mention of sleet in the 5-day forecast for interior NW NJ, SE NY and southern Connecticut at the onset of the storm. Any frozen precipitation is expected to be brief before changing over to rain by Friday morning, with little to no accumulations expected. Otherwise, rain will fall across the rest of the area, with the steadier light rain ending by at least 7-9 AM with isolated showers lasting through the evening hours.

Temperatures / Wind Outlook: The temperature forecast for Friday is currently the most uncertain aspect of the forecast. Temperatures are expected to be in the 30s to lower 40s for Thursday night with the onset of the storm, rising towards the afternoon. There are minor differences with the location of the low pressure on the models, but the area will end up near the boundary of the warm front, meaning that these minor differences have a larger impact on the forecast for the area. Should the warm front end up north of NYC, which the 18z GFS and NAM runs supported, temperatures would surge into the 60-65 degree range by Friday afternoon/evening, and with a tight pressure gradient developing, strong wind gusts in the 40-55 mph range would be possible in the late afternoon and evening hours, locally exceeding 50-55 mph at most. In this case, a wind alert would be issued for the entire area, with a possible High Wind Watch. Should the warm front end up south of NYC, however, as the CMC, UKMET and 0z NAM are showing, temperatures would remain in the 40s throughout most of the day, briefly rising into the mid 40s to lower 50s late Friday afternoon ahead of the cold front, with winds gusting up to 40 mph, locally 45-50 mph, by the evening hours.

Friday’s temperature forecast is currently not a high confidence one, as minor changes in the position of the warm front and low pressure will mean either 60-65 degrees in NYC and strong wind gusts, or 50 degrees and moderate wind gusts. For tonight’s forecast, I am expecting the warm front to reach NYC, resulting in temperatures reaching the upper 40s for most of the area, along with lower to mid 50s near NYC/western Long Island and upper 50s southwest of NYC. Gusty winds up to 40 mph, locally 45-50 mph, are expected to develop across the area as well on Friday evening. The temperature forecast is subject to minor changes, however. Tomorrow night’s update will include more information on the temperatures for Friday along with potential wind alerts for the area.

***2/23 Morning Update: The models last night, instead of solving the differences with the temperature gradient, have made it even more pronounced; with temperatures trending warmer on the models, there is expected to be a very tight gradient setting up somewhere near or just south of the area where temperatures in a short distance jump from the 40s to the 60s, perhaps even nearly 70 degrees. At this time, I am thinking that the gradient sets up over NYC, with temperatures in the upper 40s to low 50s north of NYC, mid to upper 50s near NYC and Long Island, possibly near 60 degrees, with temperatures reaching the 60s to 70 degrees in central New Jersey. This gradient is still subject to minor changes, however, and tonight’s update may either increase or decrease the expected high temperature for Friday. Regardless of the temperatures, at least a brief period of strong winds is expected on Friday evening, with winds likely gusting up to 40-50 mph across most of the area, perhaps gusting locally above 50 mph in isolated locations. Stay tuned for more information with tonight’s update.***

Weekend – Next Week: Chilly, Briefly Warmer Early Week, Then Colder

Temperatures are expected to cool down during the weekend behind the cold front, with dry and mostly sunny conditions expected. Saturday will be slightly cooler with highs in the lower 40s, with breezy winds still possible, with Sunday slightly warming up into the mid 40s for most places. A low pressure will move into the Northeast by Monday night into Tuesday, but is not expected to be strong, with the result increased cloud cover for the area, a risk of isolated showers, and temperatures warming up well into the 40s and possibly the lower 50s. Temperatures will slightly cool down into the 40s again by Wednesday with dry conditions.

The attention then turns towards late next week, when the next storm potential exists. The models are each showing a different outcome, as should be expected nearly a week away; today’s GFS runs have generally showed a strong storm moving through the region, with warm temperatures and heavy rain for the area and a significant snowstorm for parts of New England. The 12z ECM went extreme with a major snowstorm for the area, the CMC had nothing, and the NOGAPS had a suppressed coastal low. This is too far out to make any solid forecast for the storm, but the set up is still unfavorable for a snow event, with a transient weak western ridge and no blocking in the Atlantic. With these variables missing, a near ideal set up would be required for the area to see snow; one small factor goes wrong and the storm will easily end up as either rain or nothing, and at this time both of these scenarios are more likely than a snowstorm. Stay tuned for more information on this time frame as details become clearer.

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