textproduct: Wakefield

SYNOPSIS

A backdoor cold front slides across the region later today, and pushes south of the area overnight as strong high pressure builds into Quebec. Cold and damp conditions prevail Friday. The weekend turns a bit warmer, but will be variably cloudy and unsettled. A strong cold front crosses the area on Monday bringing another round of showers, followed with dry and much colder conditions through midweek.

NEAR TERM /THROUGH TONIGHT/

As of 310 AM EST Thursday...

Key Messages:

- A warm Christmas Day for most of the area, with a chance for (mainly) morning showers. The latest Wx analysis indicates weakening sfc high pressure across the local area, with low pressure off to our NW over IN/OH. NW flow prevails aloft on the NE edge of a broad upper ridge centered over the south-central CONUS. A fast moving shortwave is forecast to move SE and push through southern VA and ern NC this morning, bringing just enough lift and moisture for scattered showers (PoPs 30-40% for most). Overall, QPF will average less than 0.10" and most of the showers should be ending by late morning in the piedmont, and by early aftn to the east as the wave aloft pushes off the Carolina coast. Mostly cloudy skies on average this morning, with partly/variably cloudy skies this aftn. With decent mixing and SW winds shifting to the W, have gone a few degrees warmer than the NBM for highs, blending in the HRRR which has performed quite well over the past few days. Highs will range from the upper 60s/near 70F over south central VA and much of NE NC, to the lower 50s on the MD eastern shore, with most of the region in the low-mid 60s, or about 10-15 degrees above normal.

Behind the system, strong (near 1035mb) high pressure builds over Quebec, pushing the backdoor cold front well south of the area overnight. As the strong sfc high ridges south, clearing skies prevail with a much colder and drier airmass settling south. Lows tonight will range from the mid 20s on the MD eastern shore to the mid-upper 30s across southern VA and NE NC.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/

As of 320 AM EST Thursday...

Key Messages:

- Chilly Friday in the wake of a backdoor cold front. Rain chances increase in the afternoon and evening, with some mixed wintry precip generally confined to the far north.

The latest model suite continues in good overall agreement that sfc low pressure moves rapidly east from northern IL to the upper OH Valley by late Friday. With strong sfc high pressure anchored over eastern Canada, Friday will be characterized by "wedge" conditions (CAD). The model trends show a slightly slower arrival of overrunning moisture (with sfc pressure falls not starting until late morning or early aftn. This will lead to mainly dry conditions in the morning, with light rain and/or drizzle not really developing for most of the area until the aftn. This will allow for enough airmass modification to bring mainly just rain to the CWA, though there still appears to be a window for rain/snow changing to sleet across the MD eastern shore (and rain/sleet over northern zones W of the Bay). Given the warmth of the past few days, little to no impacts are anticipated and some of the models continue to trend even slower and farther north with little in the way of QPF into the region (just a few hundredths through 00Z/Sat). The only locations that has much of a chance for any accumulation of snow/sleet (~0.1-0.2") is the MD eastern shore. With the widespread clouds and precipitation, highs will likely struggle to get out of the upper 30s for much of the northern tier of the area with 40-45F for most of the CWA (mid-upper 40s to near 50F in NE NC and southside Hampton Roads). The initial surface low weakens over the upper OH Valley late Friday, with secondary low pressure developing off the VA- NC coast Friday night (miller B setup). The higher QPF will be Friday night (0.25" to locally 0.50+") for areas closer to the coast. However, by this time the stronger onshore flow brings milder Atlantic influence so all of this will become just rain with temperatures well above freezing.

For Saturday, the wedge airmass lingers early in the day, especially across northeastern portions of the area. There will likely be a sharp temperature gradient with highs only in the 40s across NE portions of the area and the lower 60s over the far S/SW. A light rain shower/drizzle cannot be ruled out across the MD Eastern Shore Saturday morning, but generally dry conditions elsewhere, with a partly sunny sky along and S of I-64. Clouds increase Sat night with lows ranging from near 30F NE to the upper 30s/around 40F in NE NC.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

As of 345 AM EST Thursday...

Key Messages:

- A strong cold front is now delayed until Monday, with the highest coverage of showers Sun night into Monday aftn.

- Markedly colder conditions Monday night through midweek.

The central CONUS ridge finally translates east by Sunday, but as the next area of low pressure translates rapidly NE from the mid-MS Valley to the Great Lakes with a sfc ridge in place, overrunning moisture returns, bringing a mostly cloudy day with highs near to a little above normal. The bulk of the precip stays N of the region through the day, with PoPs then increasing Sun night and Monday as the cold front finally moves in from the NW. Will have high chance to likely PoPs Monday, though this appears to be a setup where deeper moisture does not cross the Appalachians (so QPF amounts look fairly low at this time). The slower timing will keep the colder airmass delayed, with above normal temperatures both Sunday night and Monday (highs Monday in the 60s for most of the area). Much colder Monday night through Wednesday as a deep upper trough develops over the ern CONUS. At this time, highs look to be mostly in the 30s Tuesday, and in the low-mid 40s Wed. Lows mainly in the 20s. Dry conditions prevail.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

As of 1235 PM EST Thursday...

VFR conditions prevail across the terminals for the 18z/25 TAF period. The rain that passed through the area earlier today has mostly dried out, with the exception of a few showers over NE NC and the Eastern Shore. Therefore, cannot totally rule out a brief shower at ECG or SBY during the first couple hours of the period, but did leave it out of the TAFs this time since it looks like rain should miss the terminals. Otherwise, temporarily clearing out for the afternoon, then another round of BKN sweeps through tonight with a backdoor front. SW winds are gusting to ~20-25kt early this afternoon, then expecting winds to slightly diminish as they switch around to the N/NE behind the front tonight.

Outlook: Flight restrictions are likely late Friday into early Saturday with a chance for rain south, and rain likely N. SBY could see some mixed wintry precip late Friday. Low clouds could linger Saturday. Periodic flight restrictions in low clouds are possible Sunday, and in showers Sun night/Monday.

MARINE

As of 240 AM EST Thursday...

Key Messages:

- Sub-advisory marine conditions today with northerly winds increasing tonight behind a cold front. Small Craft Advisories are in effect for the coastal waters, Chesapeake Bay, Currituck Sound, and lower James River tonight through Friday.

- SCA are possible Saturday as waves increase from weak offshore low pressure develops.

High pressure is currently centered over the area early this morning allowing W winds of 5-10 kt. A disturbance will cross the local area later today with a brief period of elevated winds this morning and early afternoon as a strong low-level jet moves across the region, with a stronger surge behind a cold front tonight. During the day today, a few gusts to 20 kt is possible with the LLJ with S winds of 10-15 kt. Then behind the front tonight, winds will shift to be northerly and stronger CAA will increase winds to 15-20 kt with gusts up to 30 kt. Small Craft Advisories are in effect for the coastal waters, Ches. Bay, Currituck Sound, and lower James River generally from 7PM to 7AM Friday. Seas will rapidly increase late tonight/early Friday to 4-6 ft, possibly to 7 ft south of the VA/NC border. Although elevated seas may linger through most of Friday mainly south of Cape Charles, due to an onshore wind component, wind speeds will quickly decrease Friday afternoon and remain sub-SCA through the weekend. Another period of onshore flow could increase seas to 4-6 ft late Saturday into Sunday, although winds are forecast to be 10-15 kt with gusts to 20 kt in the coastal waters.

Elevated winds and seas return early next week ahead of and behind a strong cold front that passes over the area late Monday. Strong CAA behind the front could lead to high end SCAs. Local wind probs have a 30-40% chance of gusts to 34 kt Monday night into Tuesday, as well as ensemble models supporting the possibility of gale force gusts. Winds with this system will continued to be monitored and fine tuned with subsequent forecasts.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory from 7 PM this evening to 7 AM EST Friday for ANZ630>632-634. Small Craft Advisory from 10 PM this evening to 10 AM EST Friday for ANZ633. Small Craft Advisory from 10 PM this evening to 7 AM EST Friday for ANZ638. Small Craft Advisory from 7 PM this evening to 1 PM EST Friday for ANZ650-652-654. Small Craft Advisory from 10 PM this evening to 4 PM EST Friday for ANZ656-658.