textproduct: Wakefield

WHAT HAS CHANGED

No major changes have been made to the forecast.

KEY MESSAGES

KEY MESSAGE 1...Widespread moderate to locally heavy rainfall is expected tonight through Friday, with a few thunderstorms possible.

KEY MESSAGE 2...Drying out and becoming seasonably cool this weekend into early next week.

DISCUSSION

As of 326 PM EST Thursday...

KEY MESSAGE 1...Widespread moderate to locally heavy rainfall is expected tonight through Friday, with a few thunderstorms possible.

Afternoon weather analysis shows a broad upper trough extending over the eastern 2/3 of the United States with the stronger flow centered over the Ohio River valley. While at the surface, a sub-1000mb low sits over northern Canada while its associated cold front drags all the way down the spine of the Appalachians, while to the east high pressure sits off the coast. With the cold front slowly pushing east it is allowing the high pressure to continue to filter in a warm and humid airmass for this time of year across the local area. Cloud cover was able to clear out across the SE and Eastern Shore allowing for temperatures to rise into the upper 70s to low 80s. While across the Piedmont cloud cover and light showers have been able to persist through much of the day causing temps to reach into the low 70s.

By this evening the cold front is expected to move into the area before stalling once again. The cold front is likely to stall along the I-85 corridor allowing for showers and a possible thunderstorm to track along the boundary. The environment ahead of the boundary is favorable for heavy rainfall as weak instability and PWATS over 200+ percent of normal for early November is forecasted to be in place. Confidence is increasing that the Middle Peninsula and eastern Northern Neck, up to the Maryland Eastern Shore is likely to see moderate to heavy rainfall as the CAMS and ensembles come into better agreement. Some of the areas are likely to see 1-2" with higher totals associated with the higher precip late tonight/early tomorrow morning. While across the piedmont and and up into the RIC metro areas may receive upwards of 1" as weaker forcing will likely be in place. Friday morning and into Friday afternoon, a wave of low pressure is forecasted to move out of the NW helping to advance the cold front through the area and pushing the showers and isolated storms east. The environment will be very similar with perhaps some higher instability across the southeast and stronger upper level forcing. Withe the stronger upper level forcing this may potentially allow for more storm development. The shear vectors do support possible training of storms which may potentially lead to very localized flash flooding. The REFS ensemble looks to be the most reasonable with 1-2"+inches likely across SE VA and NE NC with possible 3"+ with any training storms. Will note that the HRRR and RRFS look to be very aggressive with widespread storm development leading to much higher totals. In addition to the possible flash flooding threat, there is also a very marginal severe threat across the south. Bulk-Shear will generally remain between 35-45kt and a ML- CAPE reaching near 500J/kg. These ingredients together could allow for a brief strong wind gusts with any stronger storm embedded in the line of showers/isolated storms tomorrow. There is also a very small tornado threat due to the weak 0-1 SRH (~100m^2/s^2), however, confidence is low at this time.

KEY MESSAGE 2...Drying out and becoming seasonably cool this weekend into early next week.

The chances of rain diminish by late Friday afternoon as the stronger cold front advances through the area. A closed low pressure will drop out of the NW and into the northern Mid- Atlantic/southern New England region on Saturday, reinforcing our northwesterly flow. Much cooler and drier air is forecasted to advect into the area, dropping high temps back to seasonable. Highs this weekend and into early next week will generally be in the mid to upper 60s. Winds Saturday will be breezy as wind gusts will be around 20-25mph out of the NW. Overnight lows will drop into the mid to upper 30s (low 40s by the coast) each night. The recent ensembles are continuing to show dry weather persisting into the middle of next week as opposed to bringing in any more rain chances.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

As of 750 PM EST Thursday...

VFR conditions are in place to the start the 00z/06 TAF period. Radar shows some light echoes moving eastward across the region but little if any precip is making it to the surface. Winds are SSE 5-10 kt ahead of a cold front that is approaching the area from the west. Expect VFR to prevail through the evening with MVFR moving into RIC after midnight. The heavier rainfall will spread from NW to SE after sunrise. IFR CIGs will likely accompany the heavier precip bands ahead of the front. Have not included thunder in the forecast at this time but a few rumbles are possible on Friday, especially for the SE terminals from late morning through the afternoon. Winds become W-NW-N 5-10 kt as the front passes. IFR CIGs likely linger for the SE terminals late in the forecast period. VSBY restrictions will be tied to precip rate with MVFR or IFR accompanying the heavier showers.

Outlook: Conditions improve Friday night into Saturday, with VFR conditions anticipated through the weekend. Some NW breezes are likely Saturday afternoon and Sunday, especially across the eastern shore.

MARINE

As of 327 PM EST Wednesday...

Key Messages: - Small Craft Advisories issued for nearshore coastal waters north of Cape Charles for 4-5ft seas overnight.

- Additional Small Craft Advisories likely Saturday into Sunday in the bay and nearshore coastal waters for elevated NW winds.

Latest obs show breezy southerly winds on the backside of offshore high pressure. Winds are generally 10-15kt. Buoy obs show seas around 4ft. These conditions continue overnight with seas gradually building toward 5ft north of Cape Charles. Went ahead and put up a Small Craft Advisory for the northern nearshore coastal waters for the overnight period to cover the 5ft seas. Winds will diminish slightly and become more southwesterly tomorrow morning, allowing seas to fall back closer to 4ft. A cold front will pass through the region tomorrow afternoon. Winds over local waters will turn to the NW behind it by late tomorrow evening. High pressure behind the front will build in more from the west than the NW, so it will take a while for the cooler, drier air to move in and initiate increased winds. It will likely take until Saturday morning for Small Craft Advisory level winds to kick in. There is fairly high confidence in SCAs in at least the Ches. Bay Saturday into Sunday. Local wind probs show 90%+ for 18kt sustained winds across most of the marine area (outside of the rivers). A more marginal case for the coastal waters, though, since probs for sustained winds or gusts of 25kt are generally 50% or less and the offshore wind direction may prevent seas from building to 5ft or more within 20nm. NW/W winds may remain breezy into next week depending on the trajectory of the high pressure to the west. As of now, though, sub-advisory conditions look to prevail early to mid week.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 7 AM EST Friday for ANZ650-652-654.