500 FXUS61 KPHI 091957 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 357 PM EDT Wed Jul 9 2025 .SYNOPSIS... A slow moving frontal boundary will waffle across the Mid- Atlantic through late week as additional disturbances move through. Bermuda high pressure will be in place through the weekend, eventually breaking down for the start of the new work week. Several disturbances will pass through over the weekend as well. && .NEAR TERM /THROUGH THURSDAY/... The Flood Watch remains unchanged and will be in effect from 5 PM this afternoon through 2 AM Thursday. Partly cloudy skies with temperatures in the mid 80s to low 90s encompass the area this afternoon. However, this will be short-lived as another round of strong to severe thunderstorms and heavy rainfall capable of producing flash flooding is expected late afternoon into the evening hours. A shortwave currently progressing through the Ohio Valley will arrive into our area this evening which will be the main culprit for our active weather today...timing still appears to be after 5-6 PM. In terms of the severe potential, a pretty similar set-up compared to Tuesday is anticipated, where the region will be settled in a corridor of modest MLCAPE and shear, with ample moisture available with a moisture loaded atmosphere. This will allow storms to form and congeal as cold pool consolidation deepens as storms track through our area this evening. Primary threat remains for damaging wind gusts capable of producing wind gusts up to 70 mph due to strong low-level lapse rates in addition to the moisture loaded downdrafts. Some isolated large hail will be possible as well, especially if any discrete cells develop ahead of the linear convection later on. As a result, SPC has maintained the SLIGHT risk for severe weather into this evening for areas south of and including the Philadelphia metro where best atmospheric parameters overlap. Further north, the threat is lesser, but more in the way of isolated storms are possible. The hydro threat on the other hand has increased across portions of the area. Due to combination of recent rainfall over the past 2 days, PWATs in excess of 2 inches, a deep warm cloud layer up to 15k feet, and increased HREF probabilities, the potential for flash flooding is quite significant. It will only take an additional 0.5- 1.0" of rainfall to cause a quick response this afternoon and evening especially in areas which have received rainfall the past few days. As a result, WPC has upgraded portions of the area to a MODERATE risk for excessive rainfall today, including the Philadelphia and Wilmington suburbs whereas the remainder of the outlook remains unchanged from earlier this morning. See the Hydrology section below for further details. Showers and storms will continue this evening with the severe threat gradually diminishing with time, but the flood threat persisting into the overnight hours. Low temperatures will be in the upper 60s to mid 70s. For Thursday, little overall change and progression is expected with the stalled boundary. With rather weak shear up into the mid-levels, in addition to the departing shortwave, areas of showers and thunderstorms are expected to re-develop at times throughout the day. With the lack of a significant forcing, the overall nature of the severe and hydro threat is anticipated to be lesser compared to Wednesday. As a result, both the SPC and WPC have a MARGINAL risk for severe weather and excessive rainfall, respectively, across portions of the area. Also, the abundance of cloud cover anticipated for much of the day, will only result in high temperatures topping out in the low to mid 80s. It will still feel quite muggy nonetheless as dew points remain in the 70s. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... The unsettled weather pattern will continue through the short term forecast period as a series of weak disturbances help promote some diurnal convection each afternoon and evening before largely dissipating overnight each night. Given the relatively weak nature of the waves, convection should generally be more scattered. However, with the stalled frontal boundary continuing to linger near our region, PWATs will remain elevated into the 1.5-2 inch range through Saturday. As a result, thunderstorms may still be capable of producing brief, heavy downpours, resulting in localized flooding. This issue may be exacerbated in areas that have seen an abundance of rainfall this week. Increasing influence from offshore high pressure may help suppress some of the convection by Saturday, particularly across the New Jersey and Delaware coasts. Otherwise, conditions will continue to be hot and muggy. Highs mainly in the mid-upper 80s are expected both Friday and Saturday with lows Thursday night and Friday only falling to right around 70. Dew points will be in the upper 60s to low 70s throughout the period as well. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... A fairly typical summertime pattern remains on tap for the Long Term period with warm and very humid conditions. Surface dew points will generally be in the low to mid 70s though it is possible that during the peak heating of the day dew points drop by a few degrees due to mixing. Highs will generally be in the mid to upper 80s, possibly around 90 in some spots. This will give way to max heat index values generally in the low to mid 90s. A series of disturbances will pass through the region from time to time, but confidence in timing and placement is low. Will generally follow the NBM and go with 30 to 50 percent PoPs for most of this time. One exception will be along the coasts of New Jersey and Delaware as offshore high pressure looks to potentially suppress convection through the NBM. The other exception looks to be the approach of stronger system from the west though this looks to be a bit delayed with the latest cycle, approaching on Monday. The NBM continues to indicate 60 percent PoPs for most of southeast PA and NW NJ for this period. Important to note that any showers and thunderstorms will mostly be in the afternoon and evening hours and there are not many factors indicating precipitation would be widespread and organized at this time. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. This Afternoon...VFR expected for the remainder of the day with southwest winds around 5-10 kt. Another round of showers and thunderstorms are expected to move in late in the day, generally after 21Z for KRDG/KABE and after 23-00Z for the I-95 terminals. For this reason, have included TEMPO groups where any storms may cause localized areas of VSBY/CIG restrictions. Moderate-high confidence. Tonight...VFR conditions to start, but will fall to MVFR and IFR especially after 04Z. Showers and thunderstorms likely for the I-95 terminals and KMIV/KACY where TEMPO groups continue. Storms may cause localized areas of VSBY/CIG restrictions along with localized higher winds. Areas of mist and patchy fog possible. Low confidence overall, especially with regard to timing. Thursday...Lingering IFR conditions should gradually improve to MVFR during the mid-late morning hours. Should further improve to VFR by mid-late afternoon. Showers and thunderstorms possible throughout the day. Moderate-low confidence. Outlook... Thursday night through Monday...Overall, VFR conditions. However, afternoon and evening SHRA/TSRA may result in brief sub-VFR conditions if a given storm passes over a terminal. Sub-VFR conditions possible at night due to fog and low clouds, but confidence low on timing and placement. && .MARINE... No marine headlines are in effect through Thursday. South-southwest winds around 10-15 kt and seas of 3-4 feet are expected through Thursday. Showers and thunderstorms are expected to occur late this afternoon and especially this evening, where localized wind gusts in excess of 34 kt are possible. Isolated showers and thunderstorms will continue into Thursday as well. Outlook... Thursday night through Monday...Sub-Small Craft Advisory conditions expected. Afternoon and evening showers and thunderstorms possible through Saturday. VSBY restrictions possible from time to time, especially at night. Rip Currents... For today, a south/southwest shore parallel wind of around 10-20 MPH and breaking waves of around 2-3 feet will result in a MODERATE risk for the Jersey Shore. With wind direction mainly offshore along the Delaware Beaches, a LOW Risk for rip currents is in place. Similar conditions are expected for Thursday so we`ll continue with a MODERATE risk for the Jersey shore and a LOW risk of rip currents for the Delaware Beaches. Rip currents occur often in the vicinities of jetties and piers and the speed of the currents are generally maximized at low tides. For specific beach forecasts, visit weather.gov/beach/phi && .HYDROLOGY... A Flood Watch remains in effect for areas along and south of the I- 78 corridor today. Rainfall of 0.5-2.0 inches, upwards of 3-4 inches fell across portions of the watch area on Tuesday. This results in a saturated surface and low FFG values within the watch area. It will not take much more than an additional 0.5-1.0 inches to cause further flooding issues, especially in southeast Pennsylvania and northern Delaware, where widespread flooding was reported on Tuesday. Rainfall rates in excess of 2-3 inches per hour are possible with any thunderstorms this afternoon and evening. Rainfall amounts up to 1 inch today are expected with localized areas of 3-5+ inches possible, especially if any storms train over the same areas. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Flood Watch until 2 AM EDT Thursday for PAZ060>062-070-071- 101>106. NJ...Flood Watch until 2 AM EDT Thursday for NJZ009-010-012>027. DE...Flood Watch until 2 AM EDT Thursday for DEZ001>004. MD...Flood Watch until 2 AM EDT Thursday for MDZ012-015-019-020. MARINE...None. && $$ SYNOPSIS...AKL NEAR TERM...DeSilva SHORT TERM...AKL LONG TERM...AKL AVIATION...AKL/DeSilva MARINE...AKL/DeSilva HYDROLOGY...DeSilva