textproduct: Wakefield

WHAT HAS CHANGED

Severe Thunderstorm Watch 457 is now in effect until 10 PM this evening for much of central and south-central Virginia up to the Northern Neck.

A Heat Advisory has been issued for Sunday for a majority of the forecast area.

The Sunday (Day 2) Marginal severe weather risk was expanded slightly west and south to include most of our Virginia counties. The Slight risk area remains largely unchanged.

KEY MESSAGES

1) A dangerous heat wave continues through this weekend.

2) Severe storms may produce widespread damaging winds this afternoon and evening, particularly from the Richmond metro northeastward into the Northern Neck and lower Maryland Eastern Shore. An Enhanced (level 3 out 5) severe storm risk has been introduced for these areas with a Slight or Marginal risk elsewhere. Additional strong-severe storms are possible Sunday and Monday.

3) Temperatures gradually trend closer to normal by early next week, with the potentially for unsettled weather.

DISCUSSION

As of 300 PM EDT Saturday...

KEY MESSAGE 1...A dangerous heat wave continues through this weekend.

Very hot and humid conditions persist over the local area this afternoon. Widespread heat indices of 110+ degrees F are being observed area-wide, with some locations even approaching or exceed 115 F. Air temperatures this afternoon range from the mid 90s to lower 100s. Extreme Heat Warnings remain unchanged and are in effect for our entire CWA, minus the NC and MD beaches where Heat Advisories are in effect. Storms/outflow later this afternoon and evening may provide some welcome relief from the heat.

The ridge will shift southward and break down further Sunday. Regardless, we are still likely to see continued hot temperatures, albeit a few degrees cooler than the previous days. Highs generally in the mid-upper 90s range, potentially nearing 100 F in the urban Richmond corridor. Peak heat indices will tend to fall shy of 110 F, but will be solidly in Heat Advisory territory (105+) for most of the forecast area. Heat Advisories have been issued from noon to 8 PM for all of the forecast area minus the MD beaches, lower VA Eastern Shore, and NC beaches. Additional showers/storms could also provide relief by the evening. A few degrees cooler again on Monday with highs "only" in the lower 90s. Additional heat headlines are possible in NE NC but relatively widespread cloud cover and afternoon convection should preclude widespread 105+ heat indices and advisories for our VA and MD counties.

KEY MESSAGE 2...Severe storms may produce widespread damaging winds this afternoon and evening, particularly from the Richmond metro northeastward into the Northern Neck and lower Maryland Eastern Shore. An Enhanced (level 3 out 5) severe storm risk has been introduced for these areas with a Slight or Marginal risk elsewhere. Additional strong-severe storms are possible Sunday and Monday.

As the ridge slowly breaks down this afternoon, there will likely be just enough forcing/ascent to support more widespread thunderstorm development later this afternoon. Storms will be favored to initiate in the vicinity of the lee trough in the afternoon and move east or northeast into the evening hours, including (likely) through portions of our CWA. There remains lingering questions on coverage and how exactly the storms will evolve and this is reflected in the varied solutions among the near-term CAMs. Regardless of the specifics, very strong instability is in place for any storm to utilize with with SBCAPE in excess of 4000-5000 J/kg. Additionally, mid-level lapse rates are unusually steep (> 7 C/km), supportive of robust/intense updrafts. The degree of the wind threat will be dependent on potential clustering/upscale growth and cold pool development. Should a robust cold pool develop, significant/widespread damaging winds are on the table given a very favorable near- surface thermodynamic environment with DCAPE currently in excess of 1500 J/kg and steep low-level rates. There could also be some higher-end severe gusts in excess of 70 mph. The best potential for this enhanced damaging wind threat would be north and especially northeast of the Richmond metro, especially on the Northern Neck and into the lower MD Eastern Shore. This is where an Enhanced (level 3/5) risk has been introduced by the Storm Prediction Center, driven by a 45% wind probability. While coverage will be tend lower with southward extent (where Slight and Marginal Risks are delineated), the aforementioned environment is supportive of severe wx areawide. Unfortunately, these storms have the potential to interfere with afternoon/evening festivities associated with the Fourth of July and users should closely monitor the evolving weather today, have backup plans in place, and have multiple ways to receive warnings. As is typical in any summer storm, frequent lightning and heavy rain are also expected in storms today- tonight.

Additional threats of strong-severe storms are on the table both Sunday and Monday, with higher confidence in more widespread coverage Monday as a shortwave trough approaches the area. Damaging wind gusts, heavy rainfall, and frequent lightning will be the primary storms threats. SPC has a slight risk across the N Sunday.

KEY MESSAGE 3...Temperatures gradually trend closer to normal by early next week, with the potential for unsettled weather.

The ridge becomes shunted to our south beyond Monday, with the upper- level flow turning quasi-zonal. This pattern is very typical for the middle of summer with daily chances for showers and storms expected in the midst of surface troughing and weak disturbances passing through aloft. Temperatures will also trend back toward seasonal norms for most of next week, generally in the lower 90s.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

As of 105 AM EDT Sunday... Earlier showers and storms have cleared the local area. VFR is expected through the night but can't completely rule out very patchy fog in areas that saw rain yesterday. Similar wx for Sunday though the coverage of afternoon/evening storms appears to be a bit less and generally confined N/NW of a RIC-SBY line. Will again cover w/ PROB30 groups at RIC and SBY for localized reduced VSBY and gusty winds. Outside of any storms, VFR prevails with SCT aftn CU inland. S winds increase to around 10 kt this afternoon, potentially up to 15 kt for the SE terminals.

Outlook: Outside of continuing chances for showers/storms and localized flight restrictions, VFR prevails through the weekend into early next week.

MARINE

As of 230 PM EDT Saturday...

Key Messages:

- Sub-SCA marine conditions are expected to prevail through the weekend, with mainly south-southwesterly winds.

- Elevated wind gusts from strong thunderstorms are possible during afternoon and evening hours today and Sunday.

High pressure continues to extend from the Southeast to Mid-Atlantic coast this afternoon. Winds are currently ~5 kt (~10 kt offshore) and mostly out of the S/SW. Some diurnal wind speed and direction variability is likely to prevail for the next few days (mainly S-SW overnight into the morning, becoming S-SE in the late aftn/evening with a slight increase in speed). The high pressure will remain in the vicinity of the local waters through at least early next week, allowing for continued, mainly light, southerly flow and benign marine conditions. Seas are ~2 ft with ~1 ft waves this afternoon and will continue through the weekend. Isolated to widely scattered tstms this weekend into early next week would be the only thing that would lead to brief higher winds and waves, with strong tstm wind gusts possible today and Sunday, primarily from mid-aftn through early evening. Any stronger wind gusts will be handled with SMWs. A very weak cold front may settle into the Carolinas by the middle of next week, but sub-SCA conditions are expected to continue.

CLIMATE

Record Highs: Richmond, VA (RIC) tied the record for today (7/4) at 100, last set in 2002.

Salisbury, MD (SBY) set a new record high today (7/4) of 102, breaking the old record of 100 from 1919.

Norfolk, VA (ORF) set a new record high today (7/4) of 100, breaking the old record of 98 degrees set in 1879.

- Site: Fri 7/3 Sat 7/4 Sun 7/5

- RIC: 100/1954 100/2002 102/2012 - ORF: 99/1954 98/1997 98/2012 - SBY: 98/1954 100/1919 102/2012 - ECG: 98/1954 100/1997 100/2012

Record High Mins:

- Site: Fri 7/3 Sat 7/4 Sun 7/5

- RIC: 77/2014 77/1900 79/2012 - ORF: 78/2014 79/2012 80/1999 - SBY: 76/2014 78/2012 81/2012 - ECG: 78/2014 78/2012 77/2024

EQUIPMENT

KAKQ radar is down due to mechanical issues without an estimated time of return.

AKQ WATCHES/WARNINGS/ADVISORIES

MD...Heat Advisory from noon today to 8 PM EDT this evening for MDZ021>024. NC...Heat Advisory from noon today to 8 PM EDT this evening for NCZ012>017-030>032. VA...Heat Advisory from noon today to 8 PM EDT this evening for VAZ048-060>062-064>069-075>090-092-097-098-509>525- 528>531. MARINE...None.