Snowstorm 2/15/14

Miguel Pierre Forecasts, Winter Wx

Models have been trending stronger and NW this system. Particularly with closing off 700mb and 850mb lows near our area. The GFS has been leading way in these trends. The 0z run tonight back a little bit from it’s 18z run. Which would given NYC around 6″ of snow and  LI and CT 6-12″ of snow. But it still more amplified than the 12z run. The 0z UKMET and ECMWF has also come in further west tonight. So my forecast will follow the 0z GFS closely. Note that initially BL temps may be warm enough for some mixing or melting at the start. Especially over LI. So this may cut-down to the low-end of these ranges.


Snowfallmap21514

2/13/14 Nor’easter Snowfall Wed PM Update

Miguel Pierre Forecasts

New snowfall map is below. The model guidance has shifted the track surface and mid-level lows further west. This means more warm air likely be able work inland. So heaviest snowfall will be falling just north and west of I-95 corridor. Snowfall basically to come two waves:

1. As warm air tries to surge in, a TROWL/strong coastal front, will be developing late tonight. Models are strong vertical velocities tomorrow morning. That could result in snowfall rates 1-3″ per hour. Some thunder and lightning is not out of the question either. After these bands move through, many coastal areas will either changeover to sleet, rain or drizzle.

2. CCB (cold-conveyor belt) will be developing later tomorrow, as the storm bombs out near out latitude. Model guidance is tracking the storm over Eastern/Central LI. So the CCB will likely be stronger with more significant additional accumulations for Western sections of the area. While Eastern areas may pickup additional 1-2″. This will have monitored closely tomorrow.

SnowfallmapWed

Nor’easter likely for Wednesday night and Thursday 2/13/14

Miguel Pierre Forecasts

Guidance has coming into consensus for a major storm along the East Coast, Wednesday night and Thursday.  The main questions are the exact track and intensity of this storm. Cold high pressure will be sliding offshore of New England on Wednesday night. This means support for cold air to remain place will be weakening, ahead of this storm. If the storm takes track too close to coast, coastal sections will likely changeover to sleet and rain and less snowfall. While heavy snow continues further inland. However, if this storm intensifies rapidly and tracks just far east, they may only be a brief mix or changeover for the coast, before going back to heavy snow.

Features that need to be watched over the next 24hrs:

1. The low coming in Midwest (the kicker). The timing, strength, and placement of this low can have  number of impacts on the east coast storm.  This system, if stronger and faster, could lead to slower development of the storm or further east track

2. The 500mb low. The sooner this low closes off, the slower, stronger, and farther west this storm will be. A closed 500mb low to south or east, is favorable for major snowstorm for the tri-state area.

3. The 700mb and 850mb lows. Where these features track are important for frontogenesis and cold-conveyor belt formation in our area. Heavier snow is favored anywhere to north and west of these lows. While more warm air or dry air intrusion, favored to south and east.

Much of the guidance today shows these mid-level lows closing off and track from Delmarva NE to Southern New England. This should put the heaviest snowfall from I-95 major cities N&W. Further S&E will snow see more sleet, rain, and dry air decreasing snowfall totals. The preliminary snowfall total map is below:

Besides snow, this storm may have other minor or moderate impacts. Such has high winds gusts to 40mph and minor tidal flooding along the coast:
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