Marine Weather and Tide Forecast for Greenwood, DE

NEAR TERM /THROUGH TONIGHT/
Weak frontal system (hard pressed to call it a "cold" front)
moving through early this morning with showers, but the system is weakening and showers will struggle to make it through the entire region before dissipating. However, some may linger past dawn, so kept some low POPs til mid morning. A bit of patchy fog has developed mainly northwest of I-95 early this morning as well, but it should not become widespread or particularly dense before quickly dissipating after sunrise. Clouds should break for sun and a pleasantly mild afternoon. After lows in the 40s and 50s, highs should reach well into the 60s this afternoon.

Tonight, clouds return as low pressure starts to develop to our west and south. Have some low end POPs across our northwestern and southern zones, especially towards morning, but overall expect it to remain dry overnight. Lows mainly in the 40s.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
A highly amplified upper-level trough will be shifting into the East during Sunday and Monday. This will support surface low pressure in the Ohio Valley and toward the eastern Great Lakes. Some guidance has this low farther east more into our area, or a secondary low that develops along the occluded front/triple point. A mild southwesterly flow ahead of this system and its associated strong cold front will result in high temperatures in the 60s for most of our area Sunday. If thicker cloud cover is delayed it could be a few degrees warmer than currently forecast, however this probably will not occur as most of the guidance has quite a bit of cloud cover all day Sunday. In addition, an area of stronger forcing arrives from the west and southwest and with moisture advection also occurring, showers are expected to develop from southwest to northeast. Some weak instability may develop especially in the coastal plain, therefore an isolated rumble of thunder cannot be ruled out. The strong cold front moves through Sunday night with some increase in wind and a quick change to cold air advection and showers coming to an end. The coldest air however is forecast to lag behind the front.

As the cold air advection increases during Monday, high temperatures may occur during the morning to midday hours before temperatures start to fall during the afternoon. The strong upper-level trough continues to arrive during Monday with shortwave energy, however much drier air is also forecast to be advecting in. The bulk of the day should be dry, however an extensive stratocumulus cloud deck may persist through the day. Some sprinkles (flurries in the Poconos)
are possible, with perhaps even a few rain or snow showers at night as the colder air depends and shortwave energy still moves through.
A notable northwesterly breeze Monday will also add a wind chill factor. The cold air will become firmly in place Monday night with low temperatures below freezing across pretty much the entire area.

LONG TERM /TUESDAY THROUGH FRIDAY/
Summary...Modified arctic air Tuesday gives way to some warming.

Synoptic Overview...A potent upper-level trough across the area Tuesday is forecast to lift out by the end of the day. Additional shortwave energy however should maintain a trough from the Great Lakes and the Northeast Wednesday and Thursday. The trough may start to shift farther to our east during Friday. At the surface, the center of high pressure slides well to our south Tuesday. A cold front may cross our area later Wednesday, then high pressure gradually approaches from the west later Thursday and Friday.

For Tuesday...A potent upper-level trough is forecast to swing across the East with modified arctic air in place. Much of the model guidance has a strong surface low inland of the Canadian Maritimes during Tuesday with strong high pressure sliding across the Gulf Coast states. This places our area in a very tight pressure gradient. The axis of the trough should be crossing our area during the day with the strong shortwave energy shifting to our east. Some guidance hints at some snow showers especially during the first half of the day, especially north of I-78. This could be mostly tied to an upstream connection to lake effect, which sometimes is carried this far east given strong enough flow and a strong trough axis present (some mid level instability). The main theme of this day however will be the cold air with high temperatures only in the low to mid 40s (30s in the higher terrain of the Poconos to far northwest New Jersey). A gusty west-northwest wind will also drive wind chills down into teens and 20s to start the day, then rising into the 30s to near 40 degrees in the afternoon. Peak wind gusts look to be in the 30-35 mph range during the day, then diminishing some at night. The air mass starts to moderate aloft already by Tuesday night, therefore while it will still be cold Tuesday night it should not be quite as cold as Monday night.

For Wednesday and Thursday...While the main upper-level trough has already departed well to our northeast Wednesday, additional shortwave energy diving southeastward from the Midwest and Great Lakes should maintain a trough into the Northeast and Mid-Atlantic regions. As this occurs, surface high pressure centered across the Southeast U.S. will track eastward. A notable breeze looks to be present both Wednesday and Thursday given a tight pressure gradient in place and the amplified synoptic pattern. A cold front may cross our area later Wednesday, however this timing will depend on the amplification of this trough once again southeastward. This front looks to be weak and moisture-starved, therefore any chance for some showers look rather low as of now. Temperatures warm some both of these days, however highs look to be near or a little below average.

For Friday...The Mid-Atlantic region may become more situated on the backside of the aformentioned upper-level trough as it gradually moves away. This will determine our temperatures as a colder air mass may be in place ahead of surface high pressure that starts to approach from the west. Low pressure near the vicinity of the Canadian Maritimes and incoming high pressure would keep a notable breeze going. As of now, this time frame looks to be precipitation- free.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.

Today...Patchy sub-VFR, perhaps even IFR early, becoming VFR by 15Z or sooner with relatively light northwest winds generally 10 kts or less. Moderate confidence.

Tonight...VFR likely prevails, though showers may encroach on the region towards dawn. Winds light and variable. Moderate confidence.

Sunday...A period of IFR conditions with showers. A thunderstorm cannot be ruled out. Winds shifts occurring ahead of with the passage of a strong cold front.

Outlook...

Monday...Mainly VFR ceilings. A snow or rain shower possible at night (20 percent). West-northwest wind gusts to about 20 knots.

Tuesday...A snow/rain shower possible mostly early, otherwise VFR.
Westerly wind gusts to around 30 knots.

Wednesday...VFR. West-southwest wind gusts up to 30 knots possible during the day.

MARINE
Small Craft Advisory for the ocean zones til late morning given seas may linger around 5 feet into the mid-late morning hours.
Bulk of today, however, should be sub-SCA, which will continue through tonight.

Outlook...

Sunday...Small Craft Advisory conditions developing, especially at night.

Monday...Small Craft Advisory conditions probable.

Tuesday and Wednesday...Gale force wind gusts probable.

PHI WATCHES/WARNINGS/ADVISORIES
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 10 AM EST this morning for ANZ450>455.