Coastal Storm to Develop This Afternoon, Impacting Mid-Atlantic and Northeast Wednesday and Thursday

A developing coastal storm may bring wintry precipitation to the I-95 corridor.  Another warm day on tap across the southwestern U.S. as an upper ridge continues to dominate.

College Park, Maryland—(ENEWSPF)—November 6, 2012 – 3:47 a.m. EST

Short Range Forecast Discussion

A disturbance within the southern branch of the jet stream should lift northward this afternoon along the southeastern U.S. coast. As a blocking ridge anchors the open Atlantic, this system is expected to continue to gain latitude with little shift to the east. The coastal system forecast to develop will definitely be a heavy rain and gusty wind producer while churning up the seas. However, recent model guidance suggests this area of disturbed weather may be nudged offshore a bit further than previously thought which would lessen the impacts over the northeastern conus. The current track of this system is expected to keep the heaviest rainfall just offshore of the New Jersey coast. With a surface ridge setting up to the north of this disturbance, enough low-level cold air will wedge itself along the I-95 corridor to bring some accumulating snows from Delaware up to Maine. This currently includes some major metropolitan cities including Philadelphia, New York City, and Boston where a few inches are possible. Keep in mind that the track of this system has been changing which would ultimately alter the impacts to the northeast. For the latest thoughts on model guidance, please visit the HPC model diagnostics discussion on the HPC website, www.hpc.ncep.noaa.gov.

An upper trough diving down from southern Saskatchewan will race southeastward toward the upper Great Lakes. This system is expected to carve out a fairly significant trough across the eastern U.S. while following a similar track to the aforementioned system over the coastal Atlantic. Unlike the preceding disturbance, this batch of energy will not have access to as much low-level moisture. As a result, precipitation amounts along the associated boundary should be lighter in nature across the upper Midwest/Great Lakes and down through the Ohio/Tennessee Valleys. Enough cold air will be in place to support a wintry mix over sections of northeastern Minnesota and northern Wisconsin.

An expansive upper ridge currently situated over the southwestern U.S. will bring another warm day to the region on Tuesday. Abundant sunshine should support highs in the 80s across the golden state with lower 90s into the desert locales. Additionally, the offshore flow regime should ultimately hold the marine layer at bay allowing the coast to even warm into the low/mid 70s. By mid-week, the ridge will shift eastward in response to an amplified trough diving down into the Pacific Northwest. This is expected to enhance the threat for showers over the northwestern U.S. by midday Tuesday and continuing into the following day.

Graphics available at www.hpc.ncep.noaa.gov/basicwx/basicwx_wbg.php

Source: noaa.gov