Spring Gap, MD Weather

This Hazardous Weather Outlook is for the Allegheny Front counties in western Maryland, eastern West Virginia, and Highland County Virginia.

Day one: Tonight

No hazardous weather is expected at this time.

Days two through seven: Wednesday through Monday

No hazardous weather is expected at this time.

Spotter information statement

Spotter activation is not expected at this time.

What has changed

The primary updates this evening were to ceiling and visibility forecasts for aviation.

Key messages

- 1) Benign weather continues through the remainder of October with near to above normal temperatures expected.

- 2) On-off rain showers are possible beginning Sunday into early next week.

Discussion

KEY MESSAGE 1: Benign weather continues through the remainder of October with near to above normal temperatures expected.

A weak front to our south will retreat northward as a warm front Wednesday. Sprawling surface high pressure will move east from New England but continue to extend southwestward into the southeastern states as it does so. Expect increasing clouds late tonight through Wednesday from two sources. A shortwave approaching from the west will bring mid and high level clouds. Meanwhile onshore flow will result in the development of low level clouds late tonight through midday Wednesday. While the coverage of those clouds are uncertain, some fog could develop toward dawn in any areas that are not seeing cloud cover. Current guidance favors this occurring in the vicinity of the I-95 corridor or Virginia piedmont. On Wednesday, expect lower temperatures in the 60s due to the persistent cloud cover.

Another round of fog and/or low clouds may develop Wednesday night in the stagnant low level airmass. However, clearing should occur more quickly by Thursday thanks to southerly low level flow and westerly flow aloft. Temperatures will respond accordingly, as many areas reach the 70s.

Overnight lows will be above normal through this stretch as well, remaining in the 40s to lower 50s.

Another dry cold front will drop into the area Friday, but cooler air will be slow to arrive. Friday could be the warmest day of the week for many areas with highs in the mid to upper 70s. High pressure will build from the Great Lakes to New England behind the front Friday night and Saturday. Highs on Saturday will be lower in the mid 60s, though still mild for this time of year. Expect increasing cloud cover on Saturday as shortwave troughs approach from the southwest and warm advection commences on the back side of the high.

KEY MESSAGE 2: On-off rain showers are possible beginning Sunday into early next week.

A broad area of low pressure will form over the Midwest and then track east late in the weekend, bringing increasing cloud cover to the region throughout the day Saturday. A stemming cold front will cause temperatures to drop Saturday as this system tracks through the Mid-Atlantic, with potential rain showers beginning on Sunday. Uncertainty remains high on total spread and rainfall accumulation as the system looks somewhat disorganized in model guidance. Regardless, this will be the first chance for rain in well over a week across the region. While temperatures remain into the upper 60s Sunday and Monday, this remains somewhat above average for the start of November.

As this system tracks offshore by Tuesday, a second, potentially more potent upper-level low could form over the Plains and make its way to the region by the middle of next week. Uncertainty remains high regarding the track of this system, but this could bring additional rainfall to the region as we get into November.

Aviation

The TAF forecast is challenging late tonight into Wednesday morning due to the potential for low stratus and/or fog. Each ensemble and deterministic/MOS source has different solutions as to what might occur. The highest confidence appears to be at CHO, where low level clouds likely bank up against the Blue Ridge. MRB will be dependent on what spills over the Blue Ridge. While they could see fog on their own, increasing mid/high clouds could limit cooling/saturation. The edge of any stratus appears to be somewhere near the Baltimore/Washington metro, with some guidance suggesting an area of fog could develop on the east side of any stratus shield. MTN appears to have the lowest chances of any restrictions. Conditions should improve to VFR by midday or early Wednesday afternoon, although mid or high level ceilings likely continue. Light winds will remain from the east or southeast through Wednesday.

Another round of fog or sub-VFR clouds could affect some of the terminals again Wednesday night into Thursday morning, although again, model solutions are disparate. Quicker clearing should occur on Thursday with southerly surface winds taking over.

VFR conditions are anticipated Friday through Saturday with shifting light winds as another dry front pushes through. Sunday has been trending drier as high pressure persists, although there is increasing uncertainty at this range of the forecast.

Marine

Light northeast to east winds expected through tonight. Winds become southeasterly Wednesday before turning southerly Thursday. Some channeling is possible at times, though overall gradients look weak. Winds stay below SCA thresholds through the end of the month.

Winds remain below SCA thresholds through the weekend. Southerly winds shift northwesterly on Friday, then southeasterly by Sunday in the wake of a cold front.

Tides/coastal flooding

Light onshore flow Wednesday into Thursday may push sensitive shoreline close to minor flood stage. Areas most at risk for reaching minor tidal flood thresholds would be places like Annapolis and Alexandria mainly during the evening tide cycles (which are astronomically higher).

Watches, warnings and advisories

DC: None. MD: None. VA: None. WV: None. MARINE: None.