NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION. Privacy and Cookie policy

ANZ541 Choptank River To Cambridge Md And The Little Choptank River- 1233 Am Est Sun Dec 10 2023
.small craft advisory in effect through this afternoon...
.gale warning in effect from this evening through Monday afternoon...
Overnight..S winds 10 kt. Waves 1 ft. A slight chance of rain.
Sun..S winds 10 to 15 kt with gusts to 20 kt. Waves 1 to 2 ft. Rain with a chance of tstms. Vsby 1 to 3 nm.
Sun night..SW winds 10 to 15 kt with gusts to 20 kt...becoming nw 20 to 25 kt with gusts to 40 kt in the late evening and overnight. Waves 2 to 3 ft. Rain with a chance of tstms. Vsby 1 nm or less.
Mon..NW winds 20 to 25 kt with gusts to 40 kt. Waves 4 ft. Rain.
Mon night..NW winds 15 to 20 kt with gusts to 25 kt. Waves 2 to 3 ft.
Tue..SW winds 5 to 10 kt. Waves 1 ft.
Tue night..SW winds 5 to 10 kt. Waves 1 ft.
Wed..NW winds 10 to 15 kt. Waves 1 ft.
Thu..NW winds 5 to 10 kt. Waves 1 ft.
winds and waves higher and visibilities lower in and near tstms.

ANZ500 1233 Am Est Sun Dec 10 2023
Synopsis for the tidal potomac and md portion of the chesapeake bay..
broad high pressure will move offshore through tonight. A strong frontal system will impact the waters Sunday into Monday. Periods of gales are likely during this time. High pressure will return Tuesday through Thursday next week. A small craft advisory will likely be needed Monday night.

FXUS61 KPHI 100557 AFDPHI

Area Forecast Discussion National Weather Service Mount Holly NJ 1257 AM EST Sun Dec 10 2023

SYNOPSIS
High pressure will remain offshore through Sunday as a potent cold front sweeps across our region Sunday night. High pressure begins to build in by later Monday and then remains in place across the region to the end of next week.

NEAR TERM /UNTIL 6 AM THIS MORNING/
As of 930 PM, a low-level southwesterly jet of 30 knots near 925 mb and warm air advection may have been responsible earlier for some sprinkles and light showers that quickly developed near and northeast of Philadelphia. Those have now shifted to our northeast and the mid clouds have thinned/cleared across much of the region. That has resulted in a quicker temperature drop especially across the coastal plain where it was much warmer earlier. Temperatures are now much closer to the dew points which is resulting in localized fog development. Clouds are expected to increase, thicken and then lower overnight so that may tend to limit the overall fog development. Made some adjustments to primarily the hourly temperature and dew point grids into the overnight to account for the latest observations/trends.

Otherwise, high pressure offshore and strong low pressure moving north of the Great Lakes will keep a southerly flow across our region tonight. Slowly increasing clouds overnight with some radiational cooling this evening. It doesn't appear that fog will become as thick as last night, but some can't be ruled out before thicker clouds arrive. We kept patchy fog in from before. Later tonight, clouds thickening and lower and a developing south to southeast flow should keep the lower atmosphere stirred up a bit. Some concern that as temperatures and dew points rise toward daybreak, some marine/advection fog may develop and possibly spread further inland some. This is of lower confidence as it may depend on the initial cloud cover.
Lows will be in the 40s, with upper 30s mainly for the Poconos and northern NJ, before temperatures rise some particularly across the coastal plain late tonight.

SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/
The big picture remains relatively intact: A potent cold front undergoing significant frontogenesis will cross through the region Sunday night. This will bring a handful of weather impacts to the region Sunday into Monday including strong winds, heavy rain, and freshwater and tidal flooding concerns. Following frontal passage, high pressure behind the front will build in Monday as precipitation tapers off, but WNW winds will remain gusty through the afternoon.

Sunday...Our cold front will be draped across much of the Appalachian range by Sunday morning and continuing to progress eastward throughout the day. Our amplified upper level trough at this point will still be positively tilted, and therefore the baroclinic forcing will not be at its strongest at this point.
Nonetheless, precipitation will likely arrive in our western areas in the morning and will increase in magnitude while spreading eastward with time. By the afternoon, moderate, to heavy rain at times, is expected across the region. Winds will be 15-20 mph sustained with gusts of 30-45 mph possible. Those higher gusts of 40- 45 mph will be felt closer to coastal areas. Strong WAA from the warm front will help raise afternoon temperatures into the 60s for most despite rainfall.

Sunday night...Cold front is expected to pass through the region overnight with the latest guidance suggesting the frontal boundary will begin moving offshore sometime after midnight. At this point, our amplified upper level trough is shifting more neutrally tilted and slightly negatively tilted, which suggests better baroclinic forcing for greater frontogenesis at this time. Additionally, latest guidance suggests a secondary coastal low developing along the front as the trough digs. As a result, we can expect precip along the frontal boundary to further intensify, with the possibility of convection. We could see a broad area of heavy rain develop along the front as a result, dropping the most intense rainfall rates during this time. Generally speaking, we can still expect a widespread 2-3 inches of rain with locally higher amounts. With this said, much of where the heaviest rainfall will occur depends heavily on the timing of the frontal boundary. With a slower frontal passage, higher rainfall amounts could stretch west of the I-95 corridor. A quicker frontal passage means west of the I-95 could see less rainfall totals with the greatest chance for the heaviest rainfall remaining east of the I-95 corridor. Regardless, the entire region remains under a Flood Watch for both urban and small stream flooding. Southerly winds could surge slightly as the front marches east, though the strongest winds will likely remain confined to the coast, up to around 40-45 mph, just shy of wind advisory criteria for the time being. High winds will contribute to growing coastal flooding concerns as well as proximity of the event to the new moon on December 12th. See coastal flooding section below.

Expect a sharp drop off in temperatures behind the cold front with mid 30s to low 40s by daybreak.

Monday...Some precipitation will linger across the area during the first half of the day as colder WNW flow takes over the region.
Areas northwest of the I-95 urban corridor (primarily Poconos, Lehigh Valley and northwest NJ, but potentially as far southeast as the northwestern most exurbs of Philly in SE PA) may see some snow mixed with rain before the system fully exits the region by the afternoon. At the highest elevations in the Poconos,latest guidance suggests that precipitation will change completely over to snow for the last few hours before exiting the area. With this in mind, snow accumulations were increased to 1-2 inches in this area but again, this is limited to the highest elevations in the northern half of Carbon and Monroe counties.

Otherwise, most locations will see some tapering rain in the morning. At this point, the upper level trough will become fully negatively tilted, inducing rapid cyclogenisis for the developing coastal low along the frontal boundary as it reaches the southern New England coast. With strong high pressure building in from the southwest and a deepening coastal low to the northeast, pressure gradients will tighten during the day Monday, resulting in a strong surge of WNW flow across the region. Winds during the day Monday will likely gust 30-40 mph across inland locations as well as along the shore. Temperatures will not warm much as a result with 40s across much of the region and mid 30s for the Poconos.

Monday night...High pressure will gain a stronger foothold across the region allowing clouds to break overnight and winds to relax to around 10-15 mph with a few gusts still reaching 20 mph.
Temperatures will be much colder with overnight lows dropping into the mid 20s.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
The forecast period after the late weekend/Monday storm departs and through the end of the week will feature dry, quiet weather, with strong high pressure in control. Went almost entirely with the NBM, and saw little to no reason to stray from that.

On Tuesday, surface high pressure will be in place over much of the Southeast U.S. and Mid-Atlantic, favoring much lighter winds than we will experience on Sunday and Monday. Expect a clear and chilly start on Tuesday, with early morning temps in the 20s. That may result in some morning fog, though dry air and a lingering breeze most of Monday night should limit the threat, so perhaps more of a patchy fog for rural/sheltered areas type of situation. Otherwise look for a sunny day with highs mainly in the 40s. Temperatures will remain slightly below mid- December seasonal averages through most of the week, with an upper-level trough extending southward from eastern Canada across the Northeast, that will only begin to lift out by Friday. On Wednesday into Wednesday night, a reinforcing shortwave trough and associated push of cold air will drop southwest from the Great Lakes to the Northeast and northern mid-Atlantic.
That may bring some scattered to broken clouds in, particularly farther northwest toward northern NJ, the Lehigh Valley and the Poconos, with perhaps some flurries possible. Otherwise the rest of the area will only notice an increased west to northwest breeze.
By Thursday, the cold air will remain, with possibly the coldest morning of the week, but as stronger surface high pressure shifts east from the Midwest across the Mid-Atlantic, skies should turn out sunny and be accompanied by fairly light winds.

High pressure will then slowly lift out across New England through Saturday, accompanied by a building upper-level ridge along the East Coast, that will portend a moderating trend along with more dry weather. A portion of the ensemble guidance along with the NBM suggest the next system may begin to spread some precipitation into our area as early as Sunday, so have 15-20 percent chance POPs then, but probabilities for precipitation are higher for next Monday.

AVIATION /06Z SUNDAY THROUGH THURSDAY/
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas...

Early this morning (through 12Z)...Mix of VFR/MVFR over the next few hours, but clouds will increase and lower to MVFR/IFR at most terminals by daybreak. Some local fog around, however the increasing clouds overnight should keep the fog from becoming as thick as Saturday morning. Low- level wind shear (LLWS)
develops overnight with 35-45 knots expected near 2000 feet AGL.
Light and variable winds becoming locally south or southeast near 5 knots early this morning. Low confidence regarding the timing/extent of the MVFR/IFR conditions including the fog coverage.

Sunday...Sub-VFR with rain arriving and becoming heavy at times during the afternoon. Light and variable winds becoming southerly 5-15 knots. Wind gusts to 25-30 knots in the afternoon especially at KMIV and KACY. Moderate confidence.

Outlook...

Sunday night...Sub-VFR. RA/+RA. S winds 20-25 knots with frequent gusts of 30-40 knots will veer westerly after strong cold frontal passage. Moderate confidence.

Monday...Sub-VFR ceilings lingering in the morning will give way to mainly VFR conditions by the afternoon. W/NW winds 20-25 knots with frequent gusts of 30-40 knots. Moderate confidence.

Tuesday...Mainly VFR. Would not rule out some patchy morning fog, but should be mainly in rural/outlying areas. Possibly affecting RDG or MIV. W/SW winds 5-10 kt.

Wednesday...VFR, but some broken CIGs around 030-050 may develop northwest of I-95. WNW winds 10-15 kt, G 20 kt.

Thursday...VFR. W winds around 5-10 kt.

MARINE
High pressure remain well offshore while low pressure and a cold front move towards the waters for Sunday. Winds and seas freshen overnight, but conditions will remain below SCA levels tonight. Fair weather this evening then patchy fog late tonight.

Sunday...Gales on the coastal ocean waters with seas building up to 7-10 feet. Strong southerly winds with gusts up to 40 knots developing, especially in the afternoon. Small Craft Advisory conditions develop on Delaware Bay with gusts up to 30 knots.
Gale Warning and SCA are in effect.

Outlook...

Sunday night...Gales. Strong southerly winds with gusts up to 40 kts will turn sharply WNW behind a strong frontal passage. Seas 8-12 feet. Gale conditions developing on the Delaware Bay with gusts around 35 knots. Gale Warning is in effect.

Monday...Gales continue. Isolated storm force wind gusts possible.
Strong WNW winds with gusts 40-45 kts will drop to 25 kts at night.
Seas around 10 feet will diminish with time to 7-9 feet at night.
Gale Warning is in effect.

Tuesday...WNW winds backing to WSW, around 10-15 kt, while some lingering seas from the Monday's departing storm system and stronger winds may still be above 5 ft, especially early in the day. That may keep a Small Craft Advisory in effect through a portion of Tuesday.

Wednesday...While fair weather is expected, another surge of cold will result in WNW winds picking back up, sustained over 15 kt.
Gusts to 25 kt may occur especially over the ocean, though we have a little less than that in the current forecast. That may result in another SCA. Seas mainly 3 to 4 ft.

Thursday...WNW winds around 8-15 kt. Seas mainly 2 to 3 ft, with sub- advisory conditions likely.

HYDROLOGY
A Flood Watch continues for the forecast area from Sunday afternoon through Monday afternoon. Low pressure and a potent cold front will bring 2 to 3 inches of rain to the region. Excessive runoff may result in some flooding of creeks, streams, and other low- lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. Most mainstem rivers are currently not forecast to go into flood, however minor flooding is forecast at Pine Brook on the Passaic River and Blackwells Mills on the Millstone River. If higher rainfall rates occur, some of the fast responding creeks may go into flood especially in southeastern Pennsylvania, and isolated flash flooding would be possible especially in urban areas.

PHI WATCHES/WARNINGS/ADVISORIES
PA...Flood Watch from this afternoon through Monday afternoon for PAZ054-055-060>062-070-071-101>106.
NJ...Flood Watch from this afternoon through Monday afternoon for NJZ001-007>010-012>027.
DE...Flood Watch from this afternoon through Monday afternoon for DEZ001>004.
MD...Flood Watch from this afternoon through Monday afternoon for MDZ012-015-019-020.
MARINE...Small Craft Advisory from 11 AM this morning to 6 PM EST this evening for ANZ430-431.
Gale Warning from 6 PM this evening to 4 PM EST Monday for ANZ430-431.
Gale Warning from 8 AM this morning to 7 PM EST Monday for ANZ450>455.

toggle option: (graph/table)

Avalon
Click for Map
Sat -- 03:38 AM EST     Moonrise
Sat -- 06:31 AM EST     -0.17 feet Low Tide
Sat -- 07:11 AM EST     Sunrise
Sat -- 01:07 PM EST     1.41 feet High Tide
Sat -- 02:22 PM EST     Moonset
Sat -- 04:43 PM EST     Sunset
Sat -- 08:13 PM EST     0.32 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Avalon, Dogwood Harbor, Maryland, Tide feet

Baltimore Harbor Approach
Click for Map
Sat -- 12:06 AM EST     0.00 knots Slack
Sat -- 02:24 AM EST     0.36 knots Max Flood
Sat -- 03:39 AM EST     Moonrise
Sat -- 04:44 AM EST     -0.00 knots Slack
Sat -- 07:12 AM EST     Sunrise
Sat -- 07:57 AM EST     -0.61 knots Max Ebb
Sat -- 10:44 AM EST     0.00 knots Slack
Sat -- 02:21 PM EST     Moonset
Sat -- 02:31 PM EST     1.05 knots Max Flood
Sat -- 04:42 PM EST     Sunset
Sat -- 06:06 PM EST     -0.00 knots Slack
Sat -- 09:20 PM EST     -0.87 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION

Baltimore Harbor Approach, Maryland Current, knots

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Dover AFB, DE,