textproduct: Wakefield

WHAT HAS CHANGED

- 12z aviation update

- Added PoPs this aftn in the piedmont, otherwise no significant changes.

KEY MESSAGES

1) Following a brief period with seasonable temperatures through Tuesday, a major heat wave is likely beginning Wednesday, peaking Thursday through Saturday, before breaking down later next weekend. This has the potential to be the most significant in both magnitude and duration since July 2012 for most of the CWA. Shower/thunderstorm chances remain very low through Friday morning.

2) Temperatures gradually trend closer to normal late in the Holiday weekend and beyond, along with a more unsettled pattern.

DISCUSSION

As of 345 AM EDT Monday...

Relatively seasonable and dry Monday and Tuesday with high pressure building down from New England. Highs in the low-mid 80s Monday and upper 80s-lower 90s Tuesday, under a mostly sunny sky.

KEY MESSAGE 1...Following a brief period with seasonable temperatures through Tuesday, a major heat wave is likely beginning Wednesday, peaking Thursday through Saturday, before breaking down later next weekend. This has the potential to be the most significant in both magnitude and duration since July 2012 for most of the CWA. Shower/thunderstorm chances remain very low through Friday morning.

The latest analysis indicates a weak frontal boundary now S of the local area pushing into southern NC). However, with the amplifying upper level ridge off to the WSW, upper level flow has become northwesterly with some additional shortwaves droppingthrough. A lot of low level moisture and relatively light flow has led to low stratus and patchy fog. There are even a few light rain showers across metro RIC, though expect most of this to diminish by sunrise. Temperatures are mostly in the low 70s. Drier air gradually pushes down from the north later today, but the NE low level flow will tend to keep a lot of clouds around through late morning/early aftn. A shortwave, currently across MI/OH is forecast to move SE, passing through the region this aftn and offshore this evening. Have added some low chc PoPs across the piedmont as this occurs this aftn. Highs today will be near to a little below average, ranging from the upper 70s/lower 80s at the immediate coast to the mid/upper 80s well inland. Relatively pleasant tonight with lows in the mid 60s to lower 70s. Trending warmer Tuesday, but still seasonable and dry with highs mid 80s to around 90F.

An impactful heat wave is then begins Wednesday, and peaks Thu- Sat. Ensembles have remained consistent at building an anomalously strong upper ridge from the TN/lower OH Valley Tuesday, slowly drifting E-NE to the central Appalachians and Mid-Atlantic Thu-Fri, and slowly breaking down from the north over the Holiday weekend. While there remain some subtle differences in the precise location, confidence is high that this setup will lead to a significant heat wave for the local area, potentially the most widespread and of longest duration since July 2012. Given a strong consensus for H5 heights >595 dm and 850 mb temps of 21-23C, highs at or above 100 F are likely, especially Thursday through Saturday. The NBM remains a few degrees above all deterministic and statistical model guidance, so continue to shave a degree or two off these values. With temperatures this high, do expect dew points to mix out quite a bit inland. This could put a cap on the higher- end heat index scenarios, but we are still likely to be near Extreme Heat Warning criteria. The weak sfc pressure gradient will also tend to allow for some aftn seabreeze development, locally bringing steady or falling late day temperatures for the immediate coast. However, these slightly lower temperatures at the immediate coast will be coupled with higher dew points. Therefore, heat indices in these areas are likely to be similar, or even higher, than inland locations. Regardless, the latest forecast shows heat indices of 105-110 F fairly widespread for Thursday through Saturday (with pockets of 110+ possible). The general trend is that the northern areas of the CWA will probably be the hottest Thu-Fri, and the southern areas peak Fri-Sat. Regarding any potential headlines, it remains a bit too early to refine down the exact details. It does appear that a Heat Advisory might be needed for inland/northern portions of the area Wednesday (while S/SE areas will tend to see peak heat indices at or below 100F). Extreme Heat headlines will likely be needed the following days. We will take another look at this in the forthcoming forecast updates, though confidence is quite high in eventually needing Extreme Heat Watches for at least the Thursday-Friday timeframe (potentially lingering into Saturday). Also confidence is generally higher in the temperature forecast and somewhat lower in the dew pt/apparent T forecast given most cases with 100+ temps tend to see dew pts briefly fall at peak heating, especially farther inland. Either way, the bottom line is that preparations should be made now for a period of very hot temperatures/heat indices late next week.

The only real opportunity for showers and storms in this pattern would be with seabreeze-initited convection along the coast. These large heat domes also bring a risk of "ring of fire" type convective complexes, i.e., thunderstorm clusters riding the northern periphery of the ridge. However, with the heat ridge centered over western VA/eastern KY, this does not appear very likely. PoPs are negligible Wednesday and Thursday, with 15-30% PoPs by late Friday as the ridge starts to break down and seabreeze convection becomes increasingly likely. This will all be better resolved as we get closer.

KEY MESSAGE 2...Temperatures gradually trend closer to normal late in the Holiday weekend and beyond, along with a more unsettled pattern.

The ensembles are in decent agreement that the ridge starts to break down late Friday/Sat, with reinforcing troughing/shortwaves gradually turning the flow aloft to the W-NW late in the weekend and beyond. It looks like a slow process, so temperatures likely stay above normal through Sunday but with higher chances for aftn/evening tstms.

AVIATION /12Z MONDAY THROUGH FRIDAY/

As of 700 AM EDT Monday... A frontal boundary has pushed S of the area, but with a light NE flow and residual low level moisture, IFR-MVFR flight restrictions prevail early this morning, and there are even a few light showers across central VA. CIGs and VSBYs will be slow to improve with IFR-MVFR CIGs likely continuing through ~13-15Z, potentially lingering longer across the SE. VFR conditions return all areas after 18Z, with SCT-BKN cumulus. NE winds will average 5-10 kt inland, and 10-15 kt for ORF/ECG. Light winds tonight and mainly VFR with some patchy fog possible between midnight and sunrise Tue.

Outlook: VFR conditions will continue through most of this week as high pressure builds S across the area and then settles offshore. Other than isolated showers/storms, mostly dry conditions are expected through the upcoming week.

MARINE

As of 330 AM EDT Monday...

Key Messages:

- Benign marine conditions are expected to prevail through much of the week.

- Moderate Rip Risk for all beaches today.

Latest morning weather analysis shows a weak cold front becoming stationary south of the waters. Winds are remaining light (less than 10kt) out of the NE. Seas are also remaining low with waves around 1- 2ft across the bay and 2-3ft across the ocean. Through the morning and into the evening tonight winds will increase out of the NE as a high pressure strengthens and moves over New England and eventually offshore. Winds will increase to around 10kt across the bay and 10- 15kt with gusts around 20 kt across the ocean. With the increase in winds expect seas to build to 3-4ft across the near shore zones (0- 20NM). While offshore (20-60NM) seas will build to 4-5ft. At this time not expecting 5ft seas to move into the nearshore zones. However, if 5ft seas were to build in the nearshore zones, they would most likely occur in the two southern zones. The NE winds will continue through this evening and into tomorrow but will decrease with winds sustained around 10kt. By tomorrow afternoon, a front will pass through the area allowing winds to shift out of the SE. These winds again will remain light around 10 kt. Looking ahead no hazardous marine conditions are expected as strong high pressure remains in control bringing hot temperatures across all waters.

Rip Currents: Continued with Moderate Rips for all beaches today due to onshore flow and 9-10 sec periods. For Tuesday, low rips are forecasted for the northern beaches and moderate for the south due to onshore flow and waves around 3ft. Will note that there is a possibility of high rip risk for tomorrow across the southern beaches. This would be due to the possibility of waves being around 4ft or higher. There is also the possibility of Moderate rips across the northern beaches and that would be because of the wave direction being more shore normal. However, confidence is both the potential upgrades are low at this time. By Wednesday low rips are forecasted for all beaches.

CLIMATE

Record Highs later next week:

- Site: Wed 7/1 Thu 7/2 Fri 7/3 Sat 7/4

- RIC: 102/1945 100/1953 100/1954 100/2002 - ORF: 100/1901 100/1901 99/1954 98/1997 - SBY: 98/2012 99/2014 98/1954 100/1919 - ECG: 101/2012 97/1953 98/1954 100/1997

Record High Mins later next week:

- Site: Thu 7/2 Fri 7/3 Sat 7/4

- RIC: 76/2014 77/2014 77/1900 - ORF: 78/2018 78/2014 79/2012 - SBY: 77/1968 76/2014 78/2012 - ECG: 76/2014 78/2014 78/2012

AKQ WATCHES/WARNINGS/ADVISORIES

MD...None. NC...None. VA...None. MARINE...None.