Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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467 FXUS61 KPHI 290748 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 348 AM EDT FRI JUL 29 2016 .SYNOPSIS... Low pressure in the near the Delmarva will strengthen as it moves eastoff the New Jersey coast today. Another area of low pressure will develop near the Delmarva Saturday night and slowly drift out to sea through Monday. Drier and less humid weather is expected by the middle of next week as high pressure builds over the region. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Surface low pressure was located over the mid Chesapeake Bay region around 3:30 AM. The feature will move east northeastward and it should pass off the coasts of Delaware and southern New Jersey this morning before moving quickly out to sea. We continue to expect a band of moderate to heavy rainfall in the lift to the northwest of the low. Scattered to isolated lightning remains possible in the vicinity of the low itself. We have removed Berks County, the Lehigh Valley, the Poconos and northwestern New Jersey from the Flash Flood Watch. While those areas will see a period of moderate rainfall early this morning, amounts should stay below an inch. The Flash Flood Watch remains in effect for the rest of our forecast area where an additional inch or two of rainfall is expected. Locally higher amounts remain possible with any well developed convection due to the availability of abundant moisture. Precipitable water values should stay in the 2.3 to 2.4 inch range for a good part of the morning. As the low makes its way out over the ocean, the precipitation will pull away to our northeast and east during the late morning and afternoon hours. The cloud cover is forecast to lift and break gradually with some sunshine developing during the afternoon. The wind is anticipated to favor the northeast to northwest quadrant for today. Speeds may increase to 10 to 15 MPH on the coastal plain and 5 to 10 MPH inland. The cloud cover and the northerly flow should keep temperatures from rising above the 80s this afternoon. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... We should remain between weather systems for tonight with the low moving farther out to sea. Weak areas of low pressure are forecast to be over the Ohio River Valley and eastern Virginia and North Carolina. High pressure is expected to be to our north. We are anticipating a partly to mostly cloudy sky with a light wind. A few light rain showers may begin to push into our region from the west after midnight. Minimum temperatures are forecast to be in the middle and upper 60s in the north and in the lower 70s in the south. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Highlights... * Scattered showers and thunderstorms with potential for locally heavy rainfall this weekend * Transition to drier and less humid weather trending a bit slower during the early to middle part of next week Details... Saturday and Sunday... A couple of additional shortwaves will move across our region this weekend along with a frontal boundary in the vicinity. Right now,it appears that the timing for the increased threat of showers and thunderstorms will be from Saturday afternoon through Sunday evening. Plenty of moisture will linger through the weekend, so the threat will remain for locally heavy rainfall. Cloud cover and showers and thunderstorms will help hold temperatures in the 80s across much of the region. But, humid conditions will persist with dew point temperatures hovering around 70 in many locations. Monday through Thursday... Each model run is trending a bit slower with the eventual transition to a drier weather pattern and the 29/00Z guidance is no different. Will keep at least a slight chance of showers and thunderstorms in the forecast through Tuesday. Likely will see diurnally driven showers and thunderstorms on Monday and then potentially another uptick on Tuesday as an upper level trough finally pushes through to sweep the stagnant frontal boundary to our south. High pressure will build over the region, bringing us drier and somewhat less humid weather. Look for high temperatures in the lower to mid 80s and dew point temperatures in the lower to mid 60s, which will be quite a change from the week to 10 days preceding it. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. An area of moderate to heavy rain will continue to move across our TAF sites early this morning. Conditions will favor the IFR and MVFR categories. The rain is forecast to begin moving out of our region and to our northeast and east during the late morning and early afternoon hours. Conditions should begin to improve gradually at that time and we are anticipating VFR conditions for the mid to late afternoon hours. VFR conditions are forecast to continue into tonight. However, some MVFR visibility restrictions may develop. The wind is expected to favor the northeast to northwest quadrant for today at speeds of 6 to 12 knots. Outlook... Sat through Sun...Shra/tsra will lower cigs/vsbys at times Moderate Confidence. Mon...Mainly VFR. Moderate Confidence. && .MARINE... Rain with embedded thunderstorms is anticipated for this morning. The precipitation should move to our northeast and east during the afternoon. Low pressure will pass off the coast early this morning, then move out to sea. A northeast to north wind is expected for today on the coastal waters of New Jersey and Delaware with speeds increasing to 10 to 20 knots. Wave heights are anticipated to build to around 3 feet on our ocean waters. Wind speeds are expected to diminish to 10 knots or less for tonight and the direction may go variable for a time. Outlook...Saturday through Tuesday... Winds come up a bit with the weak low pressure development nearly over the waters on Sunday, otherwise expect generally a light wind flow for much of the period. Biggest concern for mariners will be the risk for thunderstorms this weekend. RIP CURRENTS...The prevailing risk category for the development of dangerous rip currents along the coasts of New Jersey and Delaware for today is low. However, a northeast to north wind may bring periods of moderate risk. The probably risk for the development of dangerous rip currents on Saturday is low && .CLIMATE... GED: a record daily rainfall has occurred so far today. PHL: heading for top 10 warmest July on record. July avg temp for PHL will be about 80.9F, 8th warmest July in the period of record since 1874. ACY: already as of 850 pm this 7th wettest July on record with its monthly record of 13.09 set in 1959. The por is back to 1874. total for the month as of 850 PM: 8.34" with 1.17 today, so far. daily record rainfall today acy 2.21 - 1884 phl 3.53 - 1980 ilg 1.85 - 1913 abe 1.64 - 1979 ttn 2.84 - 1961 ged 1.07 - 1969 rdg 2.51 - 1961 mpo 4.59 - 1969 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Flash Flood Watch until noon EDT today for PAZ070-071-101>106. NJ...Flash Flood Watch until noon EDT today for NJZ008>010-012>027. DE...Flash Flood Watch until noon EDT today for DEZ001>004. MD...Flash Flood Watch until noon EDT today for MDZ008-012-015-019- 020. MARINE...None. && $$ Synopsis...99 Near Term...Iovino Short Term...Iovino Long Term...99 Aviation...Iovino/99 Marine...Iovino/99 Climate...staff is the U.S. government's official web portal to all federal, state and local government web resources and services.