Area Forecast Discussion

WHAT HAS CHANGED

The earlier surge of wind gusts with the initial frontal passage have largely diminished except over southern portions of the waters and the higher elevations. Rain showers will pivot east through the early afternoon hours.

KEY MESSAGES

- (1) Fire weather possible this afternoon and Monday.

- (2) Widespread freeze expected Monday night.

DISCUSSION

KEY MESSAGE 1...Fire weather possible this afternoon and Monday.

Depending on how much rain falls this morning and how quickly things dry out with blustery W/NW wind at ~25 mph or so, there could be a fire weather threat mainly west of the Blue Ridge. Areas further east have less time drying out and generally weaker winds.

Following a secondary cold front Mon, a strong upper-level trof and sw will pivot overhead. Very cold air at 850-500 hPa will result in very steep lapse rates, with deep inverted-V profiles noted in forecast soundings up to 8-12 kft. This will result in wind gusts of 20 to 30 mph as dry low-level air moves in. Given mid-level moisture and the sw, some cloud cover and a few sprinkles or even a light/brief graupel shower can't be ruled out. Did undercut NBM temps by a degree or two in most areas given the cold airmass.

With the overlap in very dry air and strong winds, the fire wx threat Mon needs to be monitored. It is conditional and based on how much rain falls. More detail in fire wx section below.

KEY MESSAGE 2...Widespread freeze expected Monday night.

High pressure builds overhead Mon night into Tue leading to lighter winds. The cold, dry airmass, clear skies and light to calm winds Mon night into Tue morning are likely to bring widespread frost/freeze conditions. Issued a Freeze Watch where confidence is >50% for low temps less than 32F Mon night. This is ~10 days past the median date of the last spring freeze based on 1991-2020 climatology for areas along/east of I-81. Given the warmth early this spring, many areas are ahead of schedule from a growth stand point so this freeze could be rather impactful. Should be noted areas in srn MD and east of I-95 still have a frost threat as temps generally hover 33-35F.

No frost/freeze headlines for the Alleghenies as the growing season has not started yet.

AVIATION /15Z SUNDAY THROUGH THURSDAY/

Gusts of 20 to 30 kts will linger through this eve with lighter winds tonight. A secondary cold front likely results in 20 to 30 kt gusts again heading into Mon with a spotty shower. Otherwise, VFR Sun night through Tue. Winds shift to S by Tue.

Although a few showers are possible on Wed, expect mainly VFR conditions. This theme continues into Thu as drier air moves in behind the cold front. In response to this cold front, W to SW'ly winds may gust to around 15 to 20 knots. Winds on Wed night into Thu become lighter and out of the N.

MARINE

Showers and gusty winds (SCAs) linger behind the front, with drying expected this aft. Winds become lighter tonight then increase again Mon with a secondary front. Light winds Mon night turn s'ly Tue with additional SCAs possible by Tue night.

An uptick in sw'ly winds is possible on Wed morning which may warrant SCAs over the srn waters. However, winds largely decrease to below SCA levels through the remainder of Wed into Thu as winds shift to N'ly behind the front.

FIRE WEATHER

Rain may not be sufficient to wet fuels significantly. Strong gusty winds of 35 mph with potential for gusts as high as 45 mph will create renewed fire weather concerns despite marginal humidities and the overall light rainfall more so on Mon. Given the short duration of precip (6 hours or less for most), the 100-hour fuel moisture values aren't likely to rise much at all. The 10-hour fuel moisture likely rises considerably, but drops quickly through the day today due to the drying effects of strong winds and rapidly lowering humidity especially west of the Blue Ridge and Catoctin Mountains.

Much cooler temperatures are expected Mon and Tue with a moderating trend in temps expected during the middle and second half of the week. Strongest winds look to be on Mon out of the NW with gusts to 25 mph (30 mph over ridges). For the rest of the week, winds will be on light side thanks to high pressure overhead, but humidities will be marginally low to near critical levels. The next potential for rainfall is Wed into Thu, but amounts look light again.

LWX WATCHES / WARNINGS / ADVISORIES

DC...None. MD...Freeze Watch from late Monday night through Tuesday morning for MDZ003>006-008-011-503>508. VA...Freeze Watch from late Monday night through Tuesday morning for VAZ025>031-036>040-050-051-053-055-056-501-502- 505>508-526-527. WV...Freeze Watch from late Monday night through Tuesday morning for WVZ051>053. MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ530>543.