Marine Weather and Tide Forecast for Jesterville, MD

KEY MESSAGES
1) Scattered to numerous showers and storms expected this afternoon and evening. There remains a low-end threat for a few strong-severe storms, as well as for isolated instances of flash flooding. Dry with seasonable temperatures Monday-Tuesday.

2) A major heat wave is likely beginning Wednesday, peaking Thursday and Friday. 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 300 PM EDT Sunday...

KEY MESSAGE 1...Scattered to numerous showers and storms expected this afternoon and evening. There remains a low-end threat for a few strong-severe storms, as well as for isolated instances of flash flooding. Dry with seasonable temperatures Monday-Tuesday.

Afternoon analysis places a weak frontal boundary draped (roughly) along I-64. Visible satellite imagery depicts widespread cloud cover and areas of light rain over the the region. This boundary, in conjunction with a relatively warm and moist low- level airmass and a weak shortwave aloft, should trigger scattered to numerous showers and storms over the next few hours. While obs depict dew points well into the mid 70s, the widespread cloud cover and the light precip activity has kept temps a bit cooler than forecast. This has limited instability and SPC mesoanalysis only shows around 750-1000 J/kg of MLCAPE. Therefore, would expect the convective intensities to be quite muted, at least over the the next couple of hours.

There still remains some potential for more vigorous activity later this afternoon and evening if the thermodynamic environment can recover some. This would be most favored from interior srn VA into NE NC where some CAMs show upscale growth into a southward- moving thunderstorm cluster. Loosely organized storms are possible given bulk shear values around 25 kt. SPC has maintained a marginal risk for damaging winds in far srn VA and NE NC. In similar thinking, the best risk for gusty tstm winds would be where the more favorable low-level lapse rates currently reside, which is also across srn portions of the forecast area. PWATs over 2" and slow storms motions also favor efficient rainfall rates. A "Slight" ERO remains in place across NE NC to address this potential but don't see enough model agreement and/or signal for a short-fused Flood Watch at this time.

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 2...A major heat wave is likely beginning Wednesday, peaking Thursday and Friday. 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.

An impactful heat wave is expected during the upcoming week, particularly late week. 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. 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 and Friday.
Temperatures have also trended a degree or two higher for Wednesday and there is also a nonzero chance a few areas flirt with 100 F in the Piedmont. 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. In a similar vane, 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). Regarding any potential headlines, it remains a bit too early to refine down the exact details. For example, we may need a Heat Advisory for portions of the area Wednesday, followed by Extreme Heat headlines 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. 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.

AVIATION /19Z SUNDAY THROUGH FRIDAY/
As of 140 PM EDT Sunday...

A weak frontal boundary is draped across the region this afternoon (roughly along a ORF-RIC line), with light NE winds on the N side of the boundary and light S or variable winds on the S side. SCT-BKN MVFR CIGs also remain across the region, but these should gradually scour over the next few hours, though SBY may remain MVFR through most of today. Still expect showers and storms to develop over the next few hours, becoming particularly focused near the aforementioned frontal boundary.
Would expect a chance of SHRA/TSRA at RIC and SBY first this afternoon, followed by the SE terminals (ORF, PHF, and ECG) by this evening as storms potentially grow into a cluster and slowly move to the south. Any storm could produce heavy rain, reduced VSBY, and localized higher winds. Showers/storms taper off early tonight. Widespread flight conditions are expected at all terminals later tonight into Monday morning with widespread IFR (and possible LIFR) likely due to patchy fog and low CIGs .

Outlook: VFR conditions are expected to return later Monday morning and continue through most of next 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 320 PM EDT Sunday...

Key Messages:

- Benign marine conditions are expected to prevail through much of the week. Scattered thunderstorm activity is expected late this afternoon and this evening ahead of a weak cold front.

Latest weather analysis shows high pressure east of Bermuda this afternoon, with a weak, wavy quasi-stationary frontal boundary draped across the northern portion of the local area. Light onshore flow ~5 kt nearshore allowing for a light seabreeze to set up ahead of the front. Winds to increase slightly this evening, veering around to the NNE ~5-10 kt as the front drops south across the waters into early this evening. In addition to the wind shift, scattered showers and thunderstorms will continue to focus along and just south of the front, with an isolated strong to severe storm possible that could produce gusts over 34kt and frequent lightning. Waves 1-2 ft, seas 2-3 ft, highest offshore of 20 NM in building SSE swell.

NNE winds increase to 10-15kt across the waters late this evening through Monday afternoon. Increasing swell and wind wave will build seas to 3-5 ft across central and southern waters, highest across the central and southern offshore ocean zones east of 20 NM, as a second area of high pressure builds south through midweek. There is a very low-end chance for nearshore seas to briefly reach 5 ft Monday evening into early Tuesday, but given the low chances, will hold off with any SCA issuances at this time. Otherwise, benign marine conditions are forecasted through the majority of the week. E-NE winds linger through Tuesday, veering around the S-SE Tuesday night through Wednesday night.

Rip Currents:

Moderate Rip Risk in place tomorrow for all beaches due to developing onshore flow and increasing SSE swell/8-10 seconds.
For Tuesday, moderate Rip Risk continues VA Beach and N OBX Tuesday due to continued swell/onshore flow and seas around 3ft, with Low Rip Risk Eastern Shore beaches. Low Rip Risk all beaches on Wednesday.

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.