Grove Street Park, VA Hourly Weather Updates

Key Messages

1) A wave of low pressure along a weakening frontal boundary brings scattered showers and storms to the area this afternoon into tonight. There is a Marginal Risk of severe storms across much of the forecast area this afternoon.

2) Seasonable on Saturday, becoming more unsettled again for Sunday.

3) Hot and humid with afternoon storms Monday ahead of the next cold front.

Discussion

... As of 245 PM EDT Friday...

KEY MESSAGE 1...A wave of low pressure along a weakening frontal boundary brings scattered showers and storms to the area this afternoon into tonight. There is a Marginal Risk of severe storms across much of the forecast area this afternoon.

This afternoon, a weak, diffuse frontal boundary is located from roughly central VA over to the Middle Peninsula. South of the boundary, a very hot and humid airmass is in place with temperatures ranging from the upper 80s to mid 90s and dewpoints in the mid to upper 70s. The hot temperatures combined with the high humidity have allowed for heat index values to climb to ~100 to 105 degrees, with readings of 105+ across northeast North Carolina where a Heat Advisory remains in effect until 7 PM.

Convective initiation has started along and just north of the boundary where we have already seen a couple of severe storms, one near Newport News and one just south of Salisbury, MD. Strong diurnal heating has destabilized the airmass, with MLCAPE values ~2000-3000 J/kg south of the boundary. Deep-layer shear is fairly weak along and south of the boundary (~20 to 25 knots) and strongest across the far northeast (~35 to 40 knots). Expect mainly pulse activity with potentially a few bowing segments as we head through the afternoon/evening. Damaging wind gusts of 50 to 60 mph are possible with the strongest storms. SPC has a majority of the area in a Marginal (1 out of 5 risk) for severe storms this afternoon. In addition, high moisture content (PWATs 2.0+") will yield high rain rates and local urban or poor drainage flooding. Any storms push SSE into North Carolina this evening before gradually tapering off after ~02z (10 PM).

KEY MESSAGE 2...Seasonable on Saturday, becoming more unsettled again for Sunday.

Surface high pressure north of the Great Lakes ridges south into the Mid-Atlantic on Saturday, pushing the surface boundary off to our S/SW. Light E-NE flow will usher in a slightly drier and more seasonable airmass with highs in the upper 80s. Most areas stay dry on Saturday, but isolated to scattered showers/storms will be possible in the afternoon, especially near the NC border. On Sunday, the expansive ridge over the Southern US begins to break down as a trough digs over the Midwest. Return southerly flow brings the heat and tropical moisture back into the region. Scattered to widespread afternoon/evening thunderstorms return for Sunday. Thunderstorms will again have the potential to produce strong to severe wind gusts, with SPC placing the entire forecast area in a Day 3 Marginal (1 out of 5) risk for severe storms. Locally heavy rainfall will also be possible with any of these storms and isolated instances of flooding, especially in urban or poor drainage areas, will be possible.

KEY MESSAGE 3...Hot and humid with afternoon storms Monday ahead of the next cold front.

Hot, humid conditions likely peak on Monday ahead of an approaching cold front. Highs in the low to mid 90s, combined with elevated humidity will likely necessitate additional Heat Advisories for at least our southern/southeastern counties. Scattered showers and storms are also expected Monday afternoon/evening along the frontal boundary. Drier and slightly cooler conditions arrive Tuesday into midweek.

Aviation

/00Z SATURDAY THROUGH WEDNESDAY/... As of 750 PM EDT Friday...

There is a mixed bag of flight conditions at the terminals this evening as storms move across the western half of the area. While the main clusters of thunderstorms look to miss RIC at this time, the southern terminals seem to have a shot at seeing impacts from thunderstorms, so have maintained TEMPOs for ECG, PHF, and ORF. Some intermittent MVFR CIGs are being observed at SBY, so have added a TEMPO for the next few hours. After any convection moves through the area, CIGs could drop to near MVFR at the terminals, then are forecast to start to scatter out after sunrise tomorrow. Winds will shift to the north in the wake of the front, becoming northeast tomorrow and will remain generally light.

Outlook: Scattered aftn/evening showers/storms are possible Sunday through Monday bringing the potential for occasional sub-VFR conditions. Lower shower/storm chances Tuesday through Wednesday.

Watches / Warnings / Advisories

/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None.