9:30 AM | **Major storm to pound Mid-Atlantic region with heavy rain, strong winds…coastal sections face prospects of 60+ mph wind gusts...brunt of the storm will be Monday/Monday night**

00Z GFS surface forecast map for early Monday night shows a tight pressure gradient in the Mid-Atlantic region (black lines); map courtesy tropicaltidbits.com, NOAA/EMC

Overview
Very strong high pressure in southeastern Canada will combine with an intensifying major storm system over the next 24-36 hours to produce a tightening pressure gradient in the Mid-Atlantic region.  This is likely to result in potentially damaging wind gusts past 60 mph along coastal sections of the Mid-Atlantic region (i.e., NJ, NY, Delaware) and up to 50 mph across inland locations.  In fact, hurricane force winds are possible over the open waters just off the coast of areas like Long Island, NY during the brunt of this storm.  In addition to the powerful winds, rain will last from today right into Tuesday and will come down heavily at times.  The brunt of this storm looks to be on Monday and Monday night with the combination of the strongest winds and heaviest rainfall.

00Z GFS surface forecast map for early Tuesday morning shows strong low pressure just off the Mid-Atlantic coastline; map courtesy tropicaltidbits.com, NOAA/EMC

Details
A deep, slow-moving and intensifying upper-level trough will head right through the Mid-Atlantic region over the next 24-36 hours and this will contribute greatly to intensifying surface low pressure.   In fact, this unfolding major low pressure system will see its central pressure drop to unusually deep levels in the Tennessee Valley region (to around 29.15 inches) and will likely maintain those impressive numbers as it heads towards the Mid-Atlantic coastline.  A forerunner area of rain will slide up along the I-95 corridor region today with primarily light rain and drizzle and then heavier rain pushes in late tonight.  

Lightning strikes in the overnight hours; map courtesy Weather Bell (Dr. Ryan Maue)

On Monday, winds will pick up dramatically out of the E-to-NE and the rain will become heavy at times - the heavy rain and strong winds will continue tomorrow night.  This storm is already showing signs of strength and producing severe weather down in the Deep South with numerous lightning strikes took place in the overnight hours.  

00Z GFS 500 mb height anomaly forecast map for early Monday night shows deep upper-level trough in the Mid-Atlantic region (blue); map courtesy tropicaltidbits.com, NOAA/EMC

The rain is likely now to continue well into the day on Tuesday and some colder air will wrap into the system causing a potential changeover of the rain to ice or snow across places in upstate PA and interior NW NJ.  A changeover from rain to ice or snow all the way into the immediate I-95 corridor cannot be completely ruled out at this time near the end of the storm late Monday night or Tuesday. Rainfall amounts between today and late Tuesday are likely to average 1.5 to 2.5 inches in the DC, Philly, NYC corridor, but higher amounts of up to 3 inches are possible on a localized basis. The powerful winds can certainly result in damage to tree limbs and power lines during the brunt of the storm; especially, along coastal sections where flooding is likely to reach minor-to-moderate levels for multiple high tide cycles.  The high tide of most concern would be the one coming Monday evening during the brunt of the storm.  This storm will end up affecting all areas along the Northeast US coastline over the next couple of days.

00Z GFS 500 mb height anomaly forecast map for early Tuesday morning still features a deep upper-level trough in the Mid-Atlantic region (blue); map courtesy tropicaltidbits.com, NOAA/EMC

Looking ahead, the overall weather pattern changes noticeably beginning around Thursday to that of one with much more sustained cold thanks, in part, to a major stratospheric warming event that will unfold over the next week or so. This change is likely to bring about colder weather for us going well into the month of February.  

NOAA's forecast of precipitation totals for this entire storm between today and Wednesday morning

Meteorologist Paul Dorian
Vencore, Inc.
vencoreweather.com