textproduct: Wakefield

WHAT HAS CHANGED

Removed thunder mention for far NE portions of the Forecast Area for tonight.

KEY MESSAGES

1) Showers and storms increase in coverage late this afternoon and especially this evening, pushing eastward to the coast overnight into early Sunday morning. Low pressure offshore then allows for cool and dreary conditions Sunday, with lingering rain along the coast. Drying out and becoming milder Monday.

2) There are multiple opportunities for additional rainfall next week with temperatures near to below normal.

DISCUSSION

As of 315 PM EDT Saturday...

KEY MESSAGE 1...Showers and storms increase in coverage late this afternoon and especially this evening, pushing eastward to the coast overnight into early Sunday morning. Low pressure offshore then allows for cool and dreary conditions Sunday, with lingering rain along the coast. Drying out and becoming milder Monday.

A frontal boundary has become nearly stationary from the central Appalachians southward into southern VA this aftn, with cool high pressure situated along the southern New England coast. A cool ENE flow prevails north of the boundary, with a much warmer southerly flow to the south. Temperatures show a large gradient, ranging from the 50s on the MD eastern shore, to the 80s in most of far southern VA and NE NC. Showers with embedded tstms are ongoing across the mountains, and will begin to push into the local area over the next 1-2 hrs. We are not outlooked by SPC for any severe tstms, but with steep low level lapse rates (~9C/km) to the south of the boundary, along with DCAPE values of 500-100 J/Kg there could be an isolated stronger storm with wind gusts to ~40-50 mph. Based on model soundings and the current obs, the best storm potential is south of the I-64 corridor, probably in the vicinity of the US 460 corridor. One more thing to watch for will be locally enhanced low-level shear with the front in place and the approaching low feature across southern VA. This is highly conditional, and the CAMs have generally backed off with respect to any supercells riding along the the boundary into this evening. Have removed the mention of any tstms on the eastern shore given the very cool/stable conditions there. Showers move eastward to the coast this later this evening and tonight, with the storm threat diminishing with the loss of heating. Aerial QPF should average between 0.25" and 0.50", though locally higher amounts of 1"+ are possible in areas that see several rounds of convective activity. While beneficial, this is unlikely to make a meaningful dent in the ongoing drought conditions.

The front and low pressure system move offshore Sunday. However, the sfc low will slow down and modestly deepen as a cutoff low develops aloft. This will allow sfc high pressure to reinforce and strengthen to our N. Therefore, expect a cool, dreary, and potentially wet day Sunday with a cold air damming setup. The highest PoPs are along the coast of SE VA and NE NC. A tightened pressure gradient will also allow for breezy conditions along the immediate coat. Have continued to undercut the NBM (which struggles in CAD), with highs staying in the 50s for most of the region, with some lower 60s in NE NC and south central VA. Depending on the exact configuration of the sfc pattern, particularly where the low resides, Monday could also end up being cooler than shown in the forecast, at least along the coast. Latest models show the push of dry air from the north looks strong enough to lead to a mostly sunny sky, with the exception of the immediate coast Monday morning. Overall, expect highs to range from the lower 70s in the piedmont to the lower 60s at the immediate coast.

KEY MESSAGE 2...There are multiple opportunities for additional rainfall next week with temperatures near to below normal.

A strong upper level trough/low will be in place across central Canada Tue-Wed, eventually dropping SE towards the Great Lakes and New England late in the week. At the surface, low pressure passing through the upper midwest will bring a frontal boundary through the area Tuesday, possible leading to a few showers. At this time, PoPs are 30-50%, but rainfall amounts look light as moisture is fairly limited. A potentially more substantial slug of moisture is expected late Wednesday, and PoPs from the NBM are now 70-80% with this feature. Specifics beyond this time are uncertain but chance PoPs are in place again Fri-Sat. Temperatures generally will be near to a little cooler than average for mid- late Spring with variable cloudiness.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

As of 200 PM EDT Saturday...

MVFR CIGs prevail across the NE, with VFR conditions elsewhere. Showers and tstms are approaching from the W, and will overspread the main terminals between 20Z and 23Z. Tstms are unlikely at SBY, but possible at RIC/PHF/ORF/ECG. While svr wx is generally not expected, a few storms could produce frequent lightning, gusty winds, and reduced VSBYs. Most of the widespread rainfall holds off until after 00z for the coastal terminals. Winds average E to ENE ~10 knots or less to start, remaining gusty to 20-25 kt at SBY into this evening. Widespread low- end MVFR restrictions will transition to IFR after 06-12Z. IFR CIGs linger through most of the day Sunday, gradually improving to MVFR due to moist, onshore flow.

Outlook: Model trends have been for lingering clouds near the coast Monday, which could lead to continued flight restrictions. Inland locations should dry out with primarily VFR.

MARINE

As of 300 PM EDT Saturday...

- Solid SCA conditions expected late tonight through Monday evening, as low pressure deepens offshore. Gusts to Gale Force are expected over the coastal waters Sunday into Sunday night. Gale Warnings have been issued for all coastal waters north of the VA/NC border from Sunday morning through Sunday evening.

- Nuisance to low-end minor coastal flooding is possible for communities along the lower Chesapeake Bay and tidal VA Rivers. Up to 1 foot of inundation above ground level is possible.

Afternoon weather analysis shows a weak surface low over the southern VA and northern NC. The pressure gradient has tighten across the northern half of the coastal waters ahead of a Quasi- stationary boundary. This is leading to sold SCA conditions across the coastal waters north of the Capes and the middle and upper bay. Winds across these zones remain out of the east between 15 to 20 kt with gusts upwards of 25-30kt. With the modest onshore flow this has lead to waves upwards of 3 to 4 ft across the bay zones and 5-7ft across the ocean with 6 ft seas bashing the beaches based off cameras and buoy observations. While to the south the pressure gradient south of the boundary remains weak and winds are out of the SSE around 10kt with gusts upwards 15 kt. Waves are also lower with 2-3 ft across the bay and 3 to 4 ft across the ocean.

Through tonight into tomorrow morning the boundary will lift north as the low pressure system begins to move offshore. Winds across the north will remain out of the east with winds upwards of 20 kt with gusts upwards of 25-30kt. While across the south winds will be between 10-15kt but winds will shift out of the SW. During tonight, there will be a 1-3 hr period where the winds lower below SCA criteria as the low moves over the coastal waters. However, seas across the northern ocean will remain between 5-7ft while across the bay they will be 2-3ft. By the early morning hours tomorrow, the low will deepen offshore and its cold front will push through the area bringing SCA conditions at first across all waters and by mid to late morning Gale conditions across the coastal waters north of the VA/NC border. SCA have been issued for the bay, rivers, sound and coastal waters for N winds between 20-25kt with gusts upwards of 30kt. Will also note, a short fused SCA has been issued for the coastal zone north of the VA/NC border and south of the Capes due the Gale force winds coming in later. Confidence in Gale conditions across the coastal waters north of the VA/NC border have increased and the Gale Watches have been upgraded to Gale Warnings. Winds will be out of the N between 25-30kt with gusts upwards of 35-40 kt (highest gusts well offshore). In addition to the winds, seas will rapidly increase with 4-5ft across the bay and 6-8ft across the ocean with 9-11ft well offshore. The SCA conditions are expected to be prolonged and last through all of SUnday into Monday while the Gales will drop off Sunday night. However, once the Gale warnings are dropped they will be replaced with SCA.

Winds will begin to decrease Monday night into Tuesday and that looks to be the timeframe where SCA for the bays maybe able to be dropped. While across the ocean seas will continue to remain elevated with seas remaining greater than 5ft. Will note, by the middle of next week models have hinted on an additional low pressure system that could potentially bring elevated marine conditions once again across the local waters.

Coastal Flooding....

In regards to the coastal flooding potential, tidal anomalies of 0.5 to 1 ft above normal steadily increase late tomorrow into Monday, due to strong high pressure building to the north and deepening low pressure exiting NE offshore of the Eastern Shore. The tightening pressure gradient will bring an increasingly strong NNE flow tomorrow afternoon into Monday morning wave action/increasing seas (due to both wind waves and swell). Tidal sites in the lower Chesapeake Bay, lower James River will have the best chance for minor tidal flooding impacts with the Sunday night/early Monday morning high tide cycle, with tides remaining elevated into early Tuesday. It is certainly possible that a localized round or two of coastal flood Advisories could be needed for areas in the lower bay/tidal James Sunday afternoon/evening. Will continue to monitor trends over the next 12-24 hours.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 8 AM EDT Monday for ANZ630-631. Small Craft Advisory from 6 AM Sunday to 8 AM EDT Monday for ANZ632-634>637-639. Small Craft Advisory from 8 AM Sunday to 8 AM EDT Monday for ANZ633-658. Small Craft Advisory until 7 AM EDT Sunday for ANZ650-652. Gale Warning from 7 AM to 11 PM EDT Sunday for ANZ650-652-680- 682. Small Craft Advisory until noon EDT Sunday for ANZ654. Gale Warning from noon to 11 PM EDT Sunday for ANZ654-656-684- 686. Small Craft Advisory from 8 AM to noon EDT Sunday for ANZ656.