textproduct: Wakefield

WHAT HAS CHANGED

Marginal Risk for Severe today was nudged a little farther south. Otherwise, no significant forecast changes.

KEY MESSAGES

1) Marginal Risk for Severe storms for southern VA and NE NC later today. Localized flash flooding possible this afternoon/evening, especially SE. Dry with seasonable temperatures Monday-Tuesday.

2) A major heat wave is likely later in the upcoming week into the Holiday weekend, peaking Thu-Fri. 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.

DISCUSSION

As of 330 AM EDT Sunday...

KEY MESSAGE 1...Marginal Risk for Severe storms for southern VA and NE NC later today. Localized flash flooding possible this afternoon/evening, especially SE. Dry with seasonable temperatures Monday-Tuesday.

The latest analysis indicates a broad upper level trough from Ontario to northern New England, with an upper level ridge in place over the MS Valley. At the surface, a trough of low pressure with an associated wavy frontal boundary extends E from the mid MS Valley across the OH Valley into the Delmarva. Spotty light showers are pushing off the coast of SE VA and NE NC, with another area of showers over northern VA near the sfc front, a somewhat disorganized MCS well upstream from KY to TN/NC and far SW VA. A warm humid airmass is in place locally but with mainly rain- free conditions currently. A lot of low stratus has developed and VSBYs are down to 1-3SM for much of the interior, though with dew pts mostly in the low 70s, do not expect dense fog this morning. Shortwave energy that is situated to our W will move E-SE later today, passing through southern VA and NE NC by late aftn/early evening, as the sfc front gradually sinks south through the local area. Convective coverage is expected to be low this morning, but ramp up rather quickly across northern areas by early aftn, spreading southward through the late aftn and early evening. Shear today will be modest at 15-25 kt and instability will become limited with time to the north as the low level winds shift to the NE. A Marginal SVR threat for locally damaging wind gusts has been nudged to the south, and is now confined to southern VA and NE NC. The other issue will be for localized flash flooding given PWATs at or above 2.00", mainly in urban areas given the lower FFGs. Most of Hampton Roads received a rather minimal rainfall over the past 24 hrs, and with the HRRR and RRFS not particularly organized with higher precip total, confidence is too low for a Flood Watch (but will continue to mention the threat in the HWO). Pops increase to 50-70% by mid aftn and shift south into the evening. Highs today will be held down by abundant cloud cover and the wind shift to the NE, especially over the northern 1/2 of the FA with highs only in the low-mid 80s; southern VA and NE NC will see high in the mid/upper 80s to around 90F. Showers/storm end this evening but conditions remain warm and humid overnight with lows in the upper 60s to lower 70s. Gradually becoming less humid later Monday and into Mon night/Tuesday, along with seasonable temperatures in the 80s for highs Monday and in the mid/upper 80s to lower 90s Tuesday as high pressure builds toward the area from the NNE.

KEY MESSAGE 2...A major heat wave is likely later in the upcoming week into the Holiday weekend, peaking Thu-Fri. 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.

Models 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. 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. The MEX numbers have started to trend warmer as the period gets closer, now showing a few spots hitting ~100F Thu-Fri. Given a strong consensus for H5 heights >595 dm and 850 mb temps of 21-23C, highs at or above 100F are likely Tu-Fri, and possibly Saturday for much of the region. Continued to shave off a few degrees from the NBM temperatures for highs Wednesday- Saturday; current forecast is for highs Thursday- Saturday ranging from the upper 90s to the low 100s area-wide (with the highest temperatures for the interior MD eastern shore and central and south central VA). The weak sfc pressure gradient will tend to allow some aftn seabreeze development, locally bringing steady or falling late day temperatures. The caveat will be the higher dew pts along the coast so peak heat indices will tend to be just as high. Also continued to make some adjustments downward with aftn dew pts from the NBM (especially from the I-95 corridor and points west). The latest forecast shows heat indices of 105-110 F fairly widespread for Thursday through Saturday (with pockets of 110+ possible).

The only real opportunity for showers and storms in this pattern would be with that same seabreeze triggering some isolated convection along the coast, or more broadly in "ring of fire" type convective complexes. However, with the heat ridge trending farther east with time, this does not appear very likely, and thus rain chances remain quite low Wed- Thu, with some slight chc to low chc PoPs by late Friday as if the ridge starts to break down. This will all be better resolved as we get closer. The bottom line is that preparations should be made now for a period of very hot temperatures/heat indices late next week. Heat headlines are likely to be needed for most if not all of our area during this time period.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

As of 200 AM EDT Sunday... Primarily VFR in the SE as of 06z with some patchy MVFR-IFR restrictions farther inland. MVFR/IFR cigs are likely to persist through 14-15z for most sites. ECG is expected to be generally VFR with some shallow ground fog possible around sunrise, and MVFR cigs may be slower to lift at SBY potentially lingering into the aftn. Shower/tstm chances return this aftn (lowest chance for SBY, highest southern VA and NE NC terminals). Brief IFR/MVFR conditions are possible in any showers/tstms, primarily vsby restrictions in heavy rain. Strong wind gusts are possible with any tstms, esp for PHF/ORF/ECG.

Outlook: VFR conditions are expected to return by the beginning of next week and continue through the middle of next week as high pressure builds S across the area and then settles offshore.

MARINE

As of 330 AM EDT Sunday...

Key Messages:

- Benign marine conditions are expected to prevail through much of the week. Scattered thunderstorm activity is expected today ahead of a weakening cold front.

Early morning weather analysis shows high pressure off the coast and a weak stationary front across MD. The pressure gradient ahead of the weak front remains weak allowing winds to be light out of the WSW around 10kt. Seas remain low this morning with 1ft seas in the bay and 2-3ft across the ocean. Through the day winds will shift from the WSW to the NE as the weak stationary front moves through the area. In addition to the wind shift, scattered showers and thunderstorms are expected today across the waters. Some of these storms maybe strong to severe potentially producing gusts over 34kt. Seas will likely remain the stagnant through day with around 1-2ft across the bay and 2-3ft across the ocean. Starting late tonight into Monday AM winds will slowly increase from the NE to 10-15kt across the waters with gusts nearing 20kt offshore. These breezy conditions are expected to last through all of Monday. Seas will also increase be 1-2ft across the bay and 3-4ft across the nearshore waters and 4-5ft across the 20-60NM ocean zones. Will note that that there is a low-end potential of SCA maybe needed across the southern nearshore ocean zones as NE flow typically tends to overperform with waves. However, confidence in 5ft seas in these zones is low at this time. Besides, this brief period of potential SCA conditions across the south benign marine conditions are forecasted through the majority of the week.

Rip Currents: Low rips are forecasted for today. However, there is a possibility of the Northern beaches being upgraded to moderate due to onshore flow, but that is all depending on the timing of the front and when winds will shift. There was not enough confidence at this time for an upgrade. Continues with Moderate Rips for all beaches Monday 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.

CLIMATE

Record Highs later next week:

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

- RIC: 100/1953 100/1954 100/2002 - ORF: 100/1901 99/1954 98/1997 - SBY: 99/2014 98/1954 100/1919 - ECG: 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.