textproduct: Wakefield

WHAT HAS CHANGED

- Heat Advisory was expanded to include piedmont counties and extended through Thursday.

KEY MESSAGES

1) Hot and humid conditions with heat indices around 105F expected through the rest of the week. Heat Advisories have been issued for inland locations for today and tomorrow.

2) There are daily chances for thunderstorms through Saturday. Some storms may be strong to severe with damaging winds gusts and large hail.

DISCUSSION

As of 320 AM EDT Wednesday...

KEY MESSAGE 1...Hot and humid conditions with heat indices around 105F expected through the rest of the week. Heat Advisories have been issued for inland locations for today and tomorrow.

A late summer (or early fall, depending on what definition you prefer) heat wave remains on tap for the rest of the week. The heat should peak today and tomorrow as a strong UL ridge builds, its axis just to the west of the local area. There is increased confidence in a backdoor cold front at the sfc will move in, leading to winds becoming NE and providing a little bit of relative relief from the heat near the coast. Inland temps peak in the mid to upper 90s and heat indices between 102 and 106 while coastal areas stay in the 80s and low 90s. After collaboration with neighbors, the decision was made to go ahead and expand the Heat Advisory for today to include our piedmont counties. The heat continues into tomorrow with higher confidence in widespread heat indices at or exceeding 105. This time the coastal counties will be included in the party since winds will shift back to the SW. Went ahead and extended today's heat advisories through tomorrow since confidence is high. Advisories for the coastal counties will likely be added in following forecast packages. The heat continues Friday, but a cold front passage could mean some relief, especially across northern counties. The extent of potential heat advisories will depend on exact timing of the front, but there is a pretty good chance that at least NE NC and SE VA get another round of them. We will finally see a break from the hot weather behind the front over the weekend.

KEY MESSAGE 2...There are daily chances for thunderstorms through Saturday. Some storms may be strong to severe with damaging winds gusts and large hail.

Unfortunately the confidence in the thunderstorm forecast is not as high as the confidence in the temperature forecast. Today has the lowest confidence in severe weather of the next several days with a wide variety of solutions from the CAMs. It is one of those days where the ceiling for potential impacts is high, but the confidence in storm coverage is rather low. Still, if storms can form near the local area there is chance that they just ride the boundary (backdoor front) south and sweep through with damaging wind gusts and perhaps hail. Some of the more typically aggressive CAMs, such at the NAM3k, depict this very scenario and have an MCS shooting down the I-95 corridor. SPC has outlooked the northern half of the area with a Slight clipping the NE and a marginal down to roughly the US-460 corridor.

The strong ridge aloft starts to break down/flatten late in the week. Meanwhile, a sfc cold front will approach and pass through the area sometime Friday, likely late. An initial round of storms will be possible Thursday, but coverage still looks on the low side and these chances ultimately depend on where that backdoor front is situated. The most favorable overlap of forcing, shear, and instability is expected Friday. At the surface, the aforementioned front to our N will finally make appreciable progress and descend into our local area. Aloft, NW flow will remain in place and progressively strengthen as the associated trough drops southward along the NE/Mid-Atlantic coast, increasing the deep-layer shear. This all suggests a bonafide severe wx threat for the majority of the area Friday, with the potential for several fast-moving clusters capable of widespread damaging winds, along with isolated supercells and large hail. SPC has expanded the Slight Risk for Thursday to encompass most of the area, and a similar outlook is anticipated in the updated Day 3 outlook for Friday. The risk for storms (and any potential svr wx) Saturday is dependent on where the front is situated during peak heating.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

As of 125 PM EDT Wednesday...

Generally VFR conditions will prevail at the terminals today, with the exception being SBY. A backdoor cold front moved through SBY earlier today and MVFR CIGs are currently being observed this afternoon. By this evening, the boundary should lift back towards the north and this CIGs will wash out. There are showers and thunderstorms currently upstream of our area, but confidence is low in the exact evolution of the MCS and how far south/exact track it will take so have only included a TEMPO at SBY as the line of storms is forecast to arrive around 19z. Winds will be NE for most of the afternoon then will gradually shift to the S-SW tonight through early tomorrow.

Outlook: A stronger cold front is set to pass through the area Friday night into Saturday. The front will likely trigger scattered thunderstorms each day as it slowly sags southward, which may cause flight restrictions and strong wind gusts.

MARINE

s of 230 AM EDT Wednesday...

Key Message:

- High pressure remains centered offshore through much of the week leading to sub-Small Craft Advisory conditions.

- A cold front approaches the waters late in the week and may bring elevated winds.

Early this morning, high pressure still remains in control of the local weather pattern leading to light (~5 to 10 knot) S-SW winds over the waters. A cold front is draped just north of the local waters, near the entrance of the Delaware Bay. The cold front buckles to the SW and approaches the far NE waters over the next few hours and will continue to drop south to roughly the VA/NC border by this afternoon. The front lifts back to the north as a warm front this evening into tonight. In the wake of the front, winds turn around to the NE-E ~10 knots. A cold front will approach the region Thursday into Friday with strengthening flow ahead of and behind the boundary this weekend. Guidance continues to trend lower with winds behind the front, with in-house wind probs suggesting a similar lower forecasted winds. With that being said, the water is very warm and with a cooler airmass moving over the area, this will likely lead to at least the potential for SCA conditions across the Bay. Afternoon and evening thunderstorm chances begin to ramp up today, becoming even more widespread on Thursday and especially Friday. Any storms will have the potential to be strong or severe with locally strong wind gusts, large hail, and potentially a few waterspouts. Mariners should keep a close eye on the forecast each day through Friday.

CLIMATE

Record highs through Friday, 9/4:

Richmond: Record High:

Wed (9/2) 101/2014 Thu (9/3) 99/1984 Fri (9/4) 98/2023

Norfolk: Record High:

Wed (9/2) 99/2014 Thu (9/3) 97/1977 Fri (9/4) 96/1985

Salisbury: Record High:

Wed (9/2) 97/2014 Thu (9/3) 99/1930 Fri (9/4) 95/1944

Elizabeth City: Record High:

Wed (9/2) 96/1943 Thu (9/3) 97/2020 Fri (9/4) 98/1944

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...Heat Advisory until 8 PM EDT Thursday for NCZ012>017-030>032. VA...Heat Advisory until 8 PM EDT Thursday for VAZ048-060>062- 064>069-079>083-087>090-092-097-509>520-528-529. MARINE...None.