Marine Weather and Tide Forecast for Deale, MD

KEY MESSAGES
- 1) Strong to potentially severe thunderstorms will move through the eastern half of our region through early this evening. Conditions will be hot and humid.

- 2) Hot and humid conditions return Thursday and Friday with a daily threat for strong to severe thunderstorms.

- 3) Drier conditions expected to start this weekend, before chances for showers and storms return by early next week.

DISCUSSION
KEY MESSAGE 1...Strong to potentially severe thunderstorms will move through the eastern half of our region through early this evening. Conditions will be hot and humid.

A good deal of sunshine that unfolded across the inter- mountains, Shenandoah Valley, and the Virginia Piedmont has lead to quick destabilization over the past 3 to 5 hours. Thus, a trough of low pressure that is currently moving through the region has spawned a broad band of heavy showers and strong embedded thunderstorms. This band of convection is aligned from Carroll County Maryland to Fauquier County Virginia. Thunderstorms have stayed below severe criteria but is close. So please stay tuned to your NOAA Weather Radios and any broadcasts over your cell phones and computers. We are in a Marginal Risk for severe thunderstorms from the SPC through early this evening. The main threats will be damaging wind gusts, downpours, and lightning.
Hail cannot be ruled out. CAPE is 2500 to 3000 J/kg along and east of the Blue Ridge to the metros with ML CAPE of 1500 J/kg.
In this same area, wind shear is minimal with values of 20 knots to as much as 30 knots. This convection, along most other areas that encounter a thunderstorm, should work its way out of the area around 6pm to 7pm for most. There could be some lingering showers or a storm in parts of southern Maryland until 8pm.
As for temperatures, places east of the convection have reached the upper 80s to near 90 with dewpoint temperatures reaching the lower to middle 70s. Thus, these values indicate how hot and sticky the atmosphere has become and perhaps how uncomfortable the air is to some. It will stay warm and humid tonight with a lingering shower or two.

KEY MESSAGE 2...Hot and humid conditions return Thursday and Friday with a daily threat for strong to severe thunderstorms.

Mid-level dry air will build in associated with shortwave- ridging on Thursday. Thursday's convective potential seems that will be suppressed in coverage, but hot and humid conditions will likely overcome any weak capping and may result in a threat of locally damaging downburst winds.

Severe threat Fri appears to be significant greater as ridging breaks down and height falls spread across the area supporting large scale ascent. Hotter and even more humid conditions combined with an approaching cold front will result in more widespread thunderstorm coverage, potentially severe given large CAPE values in excess of 2000 J/kg.

KEY MESSAGE 3...Drier conditions expected to start this weekend, before chances for showers and storms return by early next week.

Cold front will cross the area Fri evening with storms ending giving a dry less humid day Saturday. A weak cold front will cross the area Sunday afternoon with more showers and thunderstorms, although the amount of moisture and instability does not look overly strong.
Broad trough across the Great Lks and east of the Rockies will keep the risk of showers next week, but instability looks meager to support severe thunderstorms at this time.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/
Heavy showers and strong thunderstorms will move across the MTN, BWI, DCA and IAD terminals through early this evening. Winds will be generally southwest 10 to 15 knots gusts 20 knots.
However, strong thunderstorms could bring wind gusts of 45 to 55 knots briefly at any site over the next 4 hours.

Some patchy fog may develop tonight in areas that receive more appreciable rain and see some clearing/lighter winds.

Prevailing VFR conditions are expected on both Thursday and Friday. Thunderstorm coverage is uncertain Thursday afternoon and evening, but any storm could contain hail and strong wind gusts. There is a higher chance of strong to severe thunderstorms Friday afternoon and evening as a cold front approaches. Winds will be fairly light out of the west or southwest both days.

VFR conditions are predominantly expected through the weekend, with some reduced conditions possible on Sunday evening associated with a low chance of showers and thunderstorms. Winds flow out of the NW before shifting S Sunday.

MARINE
Small Craft Advisories remain in effect through early this evening. Special Marine Warnings may be needed late this afternoon as a band of heavy showers and strong thunderstorms move across the waters from northwest to southeast. Wind gusts over 40 knots could accompany the strong storms through early this evening. No marine hazards overnight. A recurrence of SMWs may be needed in thunderstorms Thursday afternoon and evening and then again Friday afternoon and evening due to severe thunderstorms. A break in hazards Saturday and Sunday before the next possibility of advisories and warnings become possible Sunday night through the middle of next week.

CLIMATE
Temperatures are expected to soar to as much as 15 to 20 degrees above average Thursday and Friday. This approaches or exceeds daily record values at some sites.

Below is a list of record daily high and warm low temperatures for June 11th and 12th (Thursday and Friday).

================================================================= June 11th Record Daily Highs and Warm Lows ================================================================= Site Record High Record Warm Low DCA 101 F (set in 1911) 74 F (set in 2020 +6 others)
IAD 95 F (set in 2016) 72 F (set in 2005)
BWI 99 F (set in 1911) 75 F (set in 1914)
DMH 100 F (set in 1984) 79 F (set in 1984)
NAK 96 F (set in 2000) 79 F (set in 1973)
HGR 97 F (set in 1911) 73 F (set in 2005)
MRB 101 F (set in 1911) 71 F (set in 1927 and 1922)
CHO 99 F (set in 1911) 76 F (set in 2020)

================================================================= June 12th Record Daily Highs and Warm Lows ================================================================= Site Record High Record Warm Low DCA 95 F (set in 2017 +6 others) 77 F (set in 2015)
IAD 96 F (set in 1986) 72 F (set in 1986)
BWI 96 F (set in 1986 and 1914) 77 F (set in 1947)
DMH 96 F (set in 2025 +2 others) 77 F (set in 2017 and 2015)
NAK 98 F (set in 1914) 77 F (set in 2000 and 1973)
HGR 92 F (set in 2017 +5 others) 71 F (set in 2010 +5 others)
MRB 97 F (set in 1938 and 1933) 73 F (set in 1914)
CHO 98 F (set in 1914) 72 F (set in 1947 +2 others)

LWX WATCHES/WARNINGS/ADVISORIES
DC...None.
MD...Small Craft Advisory until 8 PM EDT this evening for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ530>543.