Lutherville-Timonium, MD Weather

What Has Changed

Issued a Frost Advisory for early Tuesday morning for a small area of the north-central Virginia piedmont.

Key Messages

- 1) Cool and dry weather continues through the weekend, although a slow-moving Nor'easter off the coast will bring gusty winds along the Chesapeake Bay and minor tidal flooding at times through Friday.

Discussion

KEY MESSAGE 1...Cool and dry weather continues through the weekend, although a slow-moving Nor'easter off the coast will bring gusty winds along the Chesapeake Bay and minor tidal flooding at times through Friday.

The position of the Nor'easter hasn't changed much from yesterday at this time, a few hundred miles east-southeast of Cape Hatteras. Strong high pressure builds toward Quebec tonight into Tuesday, while the low starts to drift northward as the preceding northern stream shortwave causes a weakness in the block. This will lead to a greater pressure gradient and slightly breezier conditions Tuesday. For tonight, that also means fewer areas will become calm. In addition, dew points will be higher where the growing season continues, so frost appears unlikely tonight for most areas. However, a small area of the north-central Virginia piedmont (US-29/US-15 corridor from Manassas to Warrenton to Culpeper to Orange) is experiencing rapidly falling temperatures, slightly lower dew points, and may be more sheltered from light winds later tonight. Have hoisted a small Frost Advisory for these areas. Some patchy frost is possible elsewhere, but should be more localized.

The ridge will continue to expand north and west of the low, blocking it from substantial movement through mid week. Although some uncertainty remains in the exact track/timing of the Nor'easter, this pattern will keep the low far enough off the coast to eliminate rain potential (and clouds for that matter) across the forecast area. Overall, any impacts will be tied to coastal communities along the Chesapeake Bay where potential minor coastal flooding and gusty marine winds remain possible concerns this week. More information on those topics is included in sections below.

Temperatures will climb slightly through mid week, ending up on either side of normal values.

By Thursday, what remains of the upper reflection of the offshore closed low gradually becomes absorbed into a deep trough over eastern Canada. These adjoining features are slated to pull eastward into the Canadian Maritimes while upstream heights build across the Mississippi Valley. From Friday and into this weekend, this broad ridge axis advances eastward ahead of a trough inhabiting the western/central U.S. As this occurs, there are some hints of another upper low center getting pinched off near the Carolina coast. However, its far southward displacement should minimize any direct impacts from this system. Overall synoptic uncertainty does increase markedly toward the end of the weekend and into early next week. Most notably, it revolves around a split in the jet streams over the middle of the continent.

Looking down at the surface, a fresh area of high pressure behind the departing trough/Canadian cold front dominates through late week while becoming more centered over the northeastern U.S. by Saturday. This ensures continued tranquil weather heading toward the last week of October. Expect dry conditions along with abundant sunshine each day. The air mass will remain quite dry owing to the prevailing northerly component to the local wind fields. Most days should yield highs in the 60s (50s for the mountains). The coldest overnight periods will likely be Friday and Saturday nights as lows fall into the 30s to low 40s. With the growing season having ended from the Blue Ridge westward, it remains to be seen if any frost/freeze threats emerge off to the east.

Aviation

VFR conditions continue through the end of the week as surface high pressure builds north of the area and dry conditions persist. Winds remain primarily out of the north each day, gusting around 15-20 knots at times each afternoon. As high pressure settles overhead, winds turn lighter by Saturday.