Marine Weather and Tide Forecast for Naval Academy MD

NEAR TERM /THROUGH SATURDAY MORNING/
A Severe Thunderstorm Watch has been issued for areas generally about a county north of the Interstate 64 corridor and areas north of that into PA until 10 PM this evening. This is in response to a combination of several key features. THe first of which is a remnant outflow boundary that was laid down this morning by a line of severe thunderstorms that passed to our northeast. This boundary is gradually washing out/drifting slowly towards the southeast into a hot and humid airmass, characterized by temperatures well into the 80s and dew points into the 70s. The result of this air mass is extreme instability values, with MLCAPE in the 2000-2500+ J/kg range. Lapse rates are going to continue to steepen into the afternoon in the low- levels, and they are already pretty high for Mid-Atlantic standards (around 7 C/km) in the mid-levels. The second key feature is a remnant MCV that is moving out of the KY/WV region, with ongoing convection moving into western portions of our forecast area. The expectation is that that ongoing MCS will move off towards the northeast, but outflow from this system will reignite convection as it cross the mountains into eastern WV/western MD.

The one factor that does lead to some uncertainty is the presence of some pretty substantial westerly flow aloft.
Oftentimes, this can squash a convective threat in this region.
Guidance is generally leaning towards some development along the aforementioned boundaries however, so perhaps the remnant MCV is enough to overcome these mid-level westerlies. So, leaning more towards convection being able to develop than not. Once it does get going in our area, as mentioned previously, it is going to have a very favorable environment for explosive development and a substantial damaging wind threat into this evening as it drifts east. Additionally, given some very fat CAPE profiles, large hail would also be a substantial threat if more isolated convection is able to develop. This round of storms should move through pretty quickly into this evening, likely clearing the Chesapeake Bay by around 8-10 PM or so. Then most of the area should dry out, though a few lingering showers/storms may hang around if there are any remnant outflows hanging around.

Outside of the severe component of all of this, there could be a non-zero flash flooding threat this afternoon/evening as well. Accompanying these threats will be very heavy rainfall rates at times and could occur over areas that had already taken on a lot of rainfall in the past few days. Additionally, there could end up being some training issues along that initial west-east oriented outflow boundary set down this morning.
A Flood Watch wasn't considered at this time, largely due to the uncertain nature of the convective evolution this afternoon. A marginal risk for excessive rainfall is also highlighted for our area today for the localized potential for some flash flooding.

Another round of severe weather could be on the horizon later this evening into the overnight hours. This is still very uncertain though, and very dependent on yet another MCS developing to our west and tracking in such a way that would impact our area. Since we won't have our daytime heating, the severity could be diminished some, but the humidity, nearby trough, approaching cold front on Saturday could be enough to make it interesting in terms of severe elements overnight. At this time, would feel more confident that this occurs across central/southern VA, but can't be 100 percent certain at this time. This is very much a "wait and see what develops" scenario and will be much more in the way of NOWcasting later today.

SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/
A cold front will approach and push across the region early in the day Saturday. There had previously been a risk for severe weather during the first half of the day on Saturday. However, this threat has diminished significantly today. Thinking is that the multiple rounds of convection, especially the overnight round (severe or not) should help to kick out any lingering outflow boundaries from the region. The air mass will not have time to reload before the fropa during the morning, thus thinkingany coverage of showers/storms will be very limited.
Best chance for any severe weather looks to be off to our south and east, where the fropa won't occur until early-mid afternoon.

High temperatures will remain warm with highs in the middle to upper 80s Saturday. The big difference will be a 10+ degree dew point drop, so it will be much less humid.

Once the front pushes through the region on Saturday, winds pick up substantially out of the W, then WNW. Wind Advisories will be issued shortly for the high ridges along the Alleghany Front through Saturday afternoon. Winds remain elevated Saturday night into Sunday as well, but the extent of the Wind Advisory is just a bit uncertain at this time. It may need to be extended further in time, but later shifts can re-evaluate that threat.

Drier and cooler air will filter in during this window. Highs Sunday will be more likely in the middle 70s and seasonable for mid-May.

LONG TERM /MONDAY THROUGH FRIDAY/
The synoptic pattern will remain on the amplified side heading into next week. To start off the work week, the initial system that tracked through the Great Lakes over the weekend will have relocated to coastal New England. At the same time, an anomalous upper ridge centered over the Gulf of America will build northward as the next system sets up over the central U.S. This overall configuration will support a quiet start to the week. It is not until the influence of the upstream trough that a pattern shift ensues. At this point, Wednesday will act as that day of transition which ushers in a more unsettled pattern. Eventually this upper trough passes overhead toward the Thursday into Friday time period next week.

The start of the work week will feature the mildest temperatures of the extended forecast period. Multi-ensemble forecast trends show the downtick in temperatures, particularly in the Tuesday through Friday timeframe. While starting off in the mid 70s to low 80s underneath mostly sunny skies, winds shift to mainly easterly leading to an increase in cloud cover by Tuesday. By Wednesday, highs fall down into the mid 60s to low 70s with rain looking likely through the day. Given precipitable water values possibly into the 1.25 to 1.50 inch range, there could easily be some heavy rain signatures. With a number of locations receiving flooding rains earlier this week, there could be some risk of additional flooding given such antecedent conditions in place.

Temperatures remain below average through the remainder of the work week as the upper trough passes through. Thursday would present a chance for some residual showers before improvements occur by Friday. This would offer a return to some sunshine before the conclusion of the work week.

AVIATION /19Z FRIDAY THROUGH WEDNESDAY/
Severe thunderstorms are possible later this afternoon into the evening, thus a Severe Thunderstorm Watch has been issued through 10 PM. See the near-term section above for more details on the setup. Just know that damaging wind gusts and large hail will be the primary threat.

Another round of thunderstorms could arrive late tonight into Saturday morning. This round has the most uncertainty at this point. An MCS moving in from the Ohio Valley may make it into our region late this evening into tonight night. This could be yet another risk for damaging wind gusts, but the timing and certainty of occurrence is still just not quite there yet. So, will hopefully have more details as this moves into the TAF period.

There may be a few storms ahead of a frontal passage on Saturday as well, which could also contain gusty winds, but think this will be east of any of our terminals. Once the front passes though, winds increase substantially out of the W at around 20 to 30 knots. This could continue into Sunday, albeit a touch lighter.

VFR conditions are expected Sunday into the start of next week as high pressure maintains control across the region.

VFR conditions are likely on Monday and Tuesday in response to high pressure across the region. Initial winds will be northwesterly with afternoon gusts to around 20 knots. By Tuesday, expect a shift to northerlies and eventually over to north-northeasterlies by later in the day. Moving to an onshore flow regime may introduce additional clouds into the night. This leads to an unsettled pattern on Wednesday with lengthy restrictions expected. Periods of rain are expected with easterlies gusting to around 15 to 20 knots.

MARINE
Today's forecast continues to grow increasingly tricky area- wide. There may be some remnant boundaries laying around from this morning's storms, which could interact with Bay/River breezes to fire off convection later this afternoon/evening.
Additionally, there may even be an MCS moving towards the region from the west. This in particular is very uncertain, but any of these two scenarios could bring severe thunderstorms to the waters this evening. Will be watching closely, but SMWs will be likely if storms do develop.

Another chance for severe weather looks to push through late tonight through early Saturday. Timing and location of yet another MCS approaching from the west is still very uncertain, but conditions will be favorable for damaging wind gusts if this does traverse the mountains and make it to the waters. SMWs would likely also be needed if this feature tracks directly over our area.

There may be a few storms ahead of a frontal passage on Saturday as well, which could also contain gusty winds. This should push through rather early on in the day, giving way to drier and windy conditions in its wake. Severe threat with this round has decreased greatly, but best chance would be in the entral/southern Chesapeake Bay waters. SCA conditions likely on Saturday and Sunday as winds gust around 20-25 knots across all the waters. High pressure settles overhead Sunday night into Monday, bringing sub-SCA winds.

There may be a brief window of advisory-caliber winds on Monday morning given breezy northwesterlies. Through the day, some occasional upticks are possible before gradients weaken in response to high pressure building to the north. Winds turn more north to easterly on Tuesday ahead of the next weather maker.

TIDES/COASTAL FLOODING
Freshwater flooding will continue at Georgetown through this afternoon with the high tide cycle. The site remains in moderate flood stage. A Coastal Flood Warning is in effect for this threat. Water should recede this evening and drop back below flood stage after the overnight high tide cycle.

DC SW Waterfront and Alexandria are going to approach minor during this morning's high tide cycle, so Coastal Flood Advisories were issued in advance of this. They may end up falling just short, but will be very close. Beyond this morning's cycle, anomalies will continue to drop in the coming days, with no real concerns for coastal flooding at this time.

LWX WATCHES/WARNINGS/ADVISORIES
DC...Coastal Flood Warning until 4 PM EDT this afternoon for DCZ001.
MD...None.
VA...None.
WV...None.
MARINE...None.