####018011896#### FXUS61 KPHI 122040 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 440 PM EDT Fri Jun 12 2026 .WHAT HAS CHANGED... A Severe Thunderstorm Watch has been issued until 9 PM for areas north of Philadelphia. && .KEY MESSAGES... 1. There remains a Slight risk of severe thunderstorms this afternoon and early this evening. 2. Dangerous heat and humidity for the rest of today, then much less humid on Saturday. 3. Showers and some thunderstorms return Sunday afternoon and Sunday night, with some severe thunderstorm risk. Cooler and less humid for the first half of next week. 4. Widespread minor coastal flooding with the evening high tide cycles Saturday and Sunday along the Atlantic coast, Delaware Bay, and possibly on the tidal Delaware River. && .DISCUSSION... KEY MESSAGE 1...There remains a Slight risk of severe thunderstorms this afternoon and early this evening. While the main cold front remains located back over portions of western PA and NY as of early this afternoon, a pre-frontal trough lies over central PA. It's ahead of this trough feature where isolated to scattered showers and thunderstorms are expected to develop this afternoon and evening. Have started to see an agitated cumulus field develop over the northern two-thirds of the area on satellite (mainly from Philadelphia northward). It's in these areas where we are more likely to see some storm development as better dynamics arrive in the next several hours. A Severe Thunderstorm Watch has been issued until 9 PM for areas north of Philadelphia. Given current meso-analysis, wouldn't be surprised if convection significantly struggles to develop south of Philadelphia and into the Delmarva as there is a mid- level jet streak which is translating to a localized corridor of subsidence in these areas. The overall thermodynamics today though, are favorable for convection with wind fields aloft and high CAPEs. Strong destabilization will still support a severe threat where ever storms do materialize today; which at this time appears to be further north than south. The entire area remains highlighted in a SLIGHT risk (level 2/5) for severe thunderstorms through this evening. Damaging winds will be the main threat due to the high DCAPE and steep low level lapse rates shown in recent meso-analysis. Weak low level shear, high wetbulb zero heights, should hinder the threat for tornadoes and/or large hail. Any convection today should end by 11 PM. KEY MESSAGE 2...Dangerous heat and humidity for the rest of today, then much less humid on Saturday. Dangerous heat is expected to continue for the rest of this afternoon as high temperatures are forecast to peak into the low to mid 90s with dew points in the low to mid 70s. This results in heat indicies of 95 to 105 degrees across the majority of the area, outside of the southern Poconos. This level of heat and humidity can become dangerous quickly for sensitive individuals and those outdoors for extended periods of time. A Heat Advisory remains in effect for portions of the area until 8 PM today. A cold front is forecast to move through the region overnight, which will knock the temperatures down a few degrees and allow dew points to return to more comfortable levels for the weekend. Although it will still be hot with high temperatures in the upper 80s to low 90s over the weekend, dew points will mainly be in the upper 50s to low 60s. Therefore, heat indicies will not be far removed from the actual air temperature, thus no heat headlines are anticipated over the weekend. KEY MESSAGE 3...Showers and some thunderstorms return Sunday afternoon and Sunday night, with some severe thunderstorm risk. Cooler and less humid for the first half of next week. An expansive upper-level trough across much of eastern Canada Sunday will gradually shift eastward into early next week. Some stronger shortwave energy within the southern portion of the trough will slide across our area later Sunday. A cold front will also be tied to this feature and that will cross our area later Sunday afternoon and Sunday evening. The low to mid level flow will increase some in response to this incoming shortwave and cold front, which will also increase the warm air advection and also the low-level moisture advection. At least some of the guidance shows a rapid moisture return in the lower levels as the air mass recovers from the substantial drying on Saturday. This will result in it feeling more humid Sunday, however it is not expected to be at the levels we currently are experiencing. The main forecast challenge is the timing, coverage and intensity of convection with this incoming system. It appears to be later in the afternoon and at night regarding the timing. There will be a period of stronger synoptic forcing arriving, and with the low to mid level flow increasing some the shear will increase some as well. The amount of instability should be sufficient enough to support some thunderstorms, however the magnitude of this will determine the intensity of the thunderstorms. If sufficient instability can be realized, then some severe thunderstorms will be possible with damaging winds the main severe weather threat. Given mostly unidirectional flow ahead of the cold front, convection should tend to develop into a couple of clusters or a line, with this potentially more favorable from about the Philadelphia metro on southward. Some model forecast soundings show steep low-level lapse rates with some dry air in the mid levels. The steep low-level lapse rates would result in higher DCAPE values, which is supportive of an enhanced wind threat with any stronger thunderstorms. In the wake of the cold front, a less humid and cooler air mass overspreads our area through the first half of next week. An upper- level trough starts to approach on Tuesday and that may result in a few showers Tuesday and Wednesday, with a greater chance for some showers and thunderstorms during Thursday. KEY MESSAGE 4...Widespread minor coastal flooding with the evening high tide cycles Saturday and Sunday along the Atlantic coast, Delaware Bay, and possibly on the tidal Delaware River. A New Moon this weekend will result in higher than normal astronomical tides. Astronomical tides will generally be 1/2 foot less than minor coastal flooding thresholds, and tidal departures will be around 1 foot or so. This will result in widespread minor coastal flooding with the evening and nighttime high tide cycles Saturday and Sunday, and potentially Monday as well on the Atlantic coast and Delaware Bay. The tidal Delaware River and its tributaries could experience some spotty minor tidal flooding by Sunday night's high tide, and potentially Monday night too, but generally these astronomical tide driven flooding events produce more noteworthy impacts for the Atlantic coasts and Delaware Bay. The highest of the New Moon tides will be Sunday night and Monday night. Tidal flooding is not currently expected along the eastern shore of Chesapeake Bay. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Rest of Today...Prevailing VFR expected. Some brief restrictions are possible with isolated to scattered thunderstorms in the afternoon, mainly after 20-21Z. Winds will generally remain westerly around 10- 15 kt with occasional gusts up to 20 kt. High confidence overall, but lower confidence with regard to timing at any given terminal. Tonight...VFR. Any residual showers or thunderstorms should end by 00-02Z. Westerly winds early will shift to northwest around 5-10 kt overnight in wake of a cold front. High confidence. Saturday...VFR/SKC. West-northwest winds around 5-10 kt. High confidence. Outlook... Saturday night...VFR. Sunday...Sub-VFR conditions probable for a time due to showers and some thunderstorms, especially in the afternoon and evening. Monday...VFR. Northwesterly wind gusts to 20 knots possible. Tuesday and Wednesday...Some sub-VFR conditions with some showers possible. && .MARINE... No marine headlines are in effect through Saturday. Southwest winds around 10-15 kt this afternoon will become northwest tonight in wake of a frontal passage. Northwest winds will continue through Saturday morning, before transitioning back to southwest by Saturday afternoon. Seas generally around 2-3 feet, locally up to 4 feet. Isolated to scattered thunderstorms possible on all marine waters through this evening. Otherwise, fair weather is expected on Saturday. Outlook... Saturday night...No marine hazards anticipated. Sunday...A brief period of Small Craft Advisory conditions are possible in the afternoon and evening due to wind gusts to 25 knots. Monday through Wednesday...No marine hazards anticipated. Rip Currents... For Saturday, a medium period 8 second swell, offshore winds, and breaking waves 2 feet or less will result in a LOW risk for development of dangerous rip currents at the Jersey Shore and Delaware Beaches. For Sunday, winds become southerly and increase to around 15-20 MPH. However, with a medium period swell around 8 seconds continue, breaking waves will be again 2 feet or less, for most beaches. The exception will be at southern facing beaches in Cape May and Atlantic counties where breaking waves in the surf zone will be up to 3 feet as the winds will be most directly onshore here. Therefore, the risk for the development of dangerous rip currents will be higher for these beaches, and a MODERATE risk is currently forecast for these two counties. For the remainder of the Jersey Shore and the Delaware Beaches, a LOW risk for the development of dangerous rip currents is forecast. Ocean water temperatures are mostly in the mid to upper 60s. For specific beach forecasts, visit weather.gov/beach/phi && .CLIMATE... A very hot and humid airmass continues through today. Some record high and warmest low temperatures could be challenged. Location 6/12 Record Warmest Low/Year Mount Pocono 69/2005 Allentown 70/1942 Reading 75/1958 Philadelphia 75/2015 Trenton 72/2015 & 2017 Atlantic City Airport 73/1973 & 2015 Atlantic City Marina 79/2016 Wilmington 73/2015 Georgetown 73/1947, 1973, 1986, & 2017 Location 6/12 Record Highs/Year Mount Pocono 87/1967 Allentown 92/1949, 1961, 2015, & 2017 Reading 95/1984 Philadelphia 95/1947 & 2015 Trenton 94/1933 Atlantic City Airport 94/2017 Atlantic City Marina 93/1880 & 1914 Wilmington 96/1933 Georgetown 95/2017 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Heat Advisory until 8 PM EDT this evening for PAZ060>062-070- 071-101>106. NJ...Heat Advisory until 8 PM EDT this evening for NJZ001-007>010- 012>015-017>020-027. DE...Heat Advisory until 8 PM EDT this evening for DEZ001. MD...None. MARINE...None. && $$ DISCUSSION...AKL/DeSilva/Gorse AVIATION...DeSilva/Gorse MARINE...AKL/DeSilva/Gorse ####018009706#### FXUS61 KLWX 122044 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 444 PM EDT Fri Jun 12 2026 .WHAT HAS CHANGED... A Severe Thunderstorm Watch has been issued for much of the forecast area through 9 PM. A Small Craft Advisory has been issued for the northern Bay and Upper Tidal Potomac through 10 PM. && .KEY MESSAGES... - 1) Hot and humid conditions persist today with another round of strong to severe thunderstorms expected. - 2) Dry conditions are expected behind a cold front on Saturday, before chances for severe thunderstorms return on Sunday. - 3) A cooler and drier pattern that settles over the region early next week will give way to a return to warm and humid conditions and the potential for strong thunderstorms on Thursday. && .DISCUSSION... KEY MESSAGE 1...Hot and humid conditions persist today with another round of strong to severe thunderstorms expected. Temperatures have climbed into the mid to upper 90s this afternoon, with dewpoints in the 60s to lower 70s. Heat Advisories remain in effect through 8 PM for much of the area. Thunderstorms have developed over the last hour or two within a surface trough to the east of the Blue Ridge, primarily to the south of I-66/US-50. This activity is expected to gradually drift off toward the south and east over time. Additional thunderstorms are also forming to the west of the mountains across West Virginia and are expected to progress eastward over time. Coverage of showers and storms has been much lesser to the north of I-66/US-50, where downslope westerly flow to the north/west of a surface trough axis has led to deeper mixing, decreasing dewpoints, lesser instability, and lesser surface convergence. The activity on radar currently is mostly cellular in nature, but there may be a tendency for some upscale growth over time as cold pools expand and mature. Two rounds of storms could be possible to the east of the Blue Ridge/south of I-66/US-50 with the ongoing activity and the potential for the thunderstorms over WV to move through later this evening. The potential for this to occur will be greater the further south one goes. The threat for thunderstorms should gradually wind down through the evening as the system's cold front moves through from northwest to southeast. In terms of hazards, damaging winds should be the primary threat with a high DCAPE environment in place (values in excess of 1000 J/kg). SPC has issued a Severe Thunderstorm Watch for much of the forecast area through 9 PM (excluding northern MD to the west of Baltimore County, as well as northern portions of the WV Panhandle). The threat for flooding looks to be relatively low, but an isolated instance or two can't be completely ruled out if cell mergers lead to a localized prolonged period of heavy rain (best chance for this would be across Central Virginia toward Fredericksburg). KEY MESSAGE 2...Dry conditions are expected behind a cold front on Saturday, before chances for severe thunderstorms return on Sunday. Mostly sunny skies and less humid conditions are expected tomorrow in the wake of tonight's cold frontal passage. It will still be hot, with highs in the upper 80s to around 90, but it will feel noticeably cooler and less humid as dewpoints drop into upper 50s and low 60s. By Sunday another shortwave disturbance will rotate around the base of the broad upper low located to our north, tracking through the Ohio Valley. As this shortwave approaches, the low- level mass response ahead of it will draw deeper moisture northward into our area within southerly flow. Dewpoints will climb into the lower 70s once again while height falls simultaneously occur aloft. The net result of that will be building instability. This instability will overlap with increasing wind fields aloft. The combination of increasing instability, shear, and large scale forcing for ascent ahead of the shortwave and an approaching cold front will lead to the development of thunderstorms during the afternoon, some of which could be severe. There's still a fair amount of spread in guidance with respect to the timing and exact placement of the storms, but as of now the threat looks to be greatest to the east of the Blue Ridge. SPC currently has much of the forecast area outlooked in a Slight Risk for severe thunderstorms on Sunday. The system's cold front will move through Sunday night, advecting cooler and drier air into the region, which will bring the threat for severe thunderstorms to an end. KEY MESSAGE 3...A cooler and drier pattern that settles over the region early next week will give way to a return to warm and humid conditions and the potential for strong thunderstorms on Thursday. Upper level troughing is forecast to build over the region early next week and remain in place through Wednesday. This pattern will bring much cooler conditions to the region with daily high temperatures in the mid to upper 70s to lower 80s favored Monday through Wednesday. A combination of mid level disturbances and moisture will keep skies partly to mostly cloudy with on and off chances for showers. Model ensembles have the troughy pattern starting to break down on Thursday allowing warm and humid conditions to return to the region. Increasing moisture and temperatures along with a potential frontal passage will bring a chance for showers and thunderstorms on Thursday. Depending on the strength of the upper level shortwave driving the cold front, there could be a risk for strong thunderstorms capable of producing some gusty winds. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... Storms are ongoing across the region currently. One round has formed within a surface trough to the east of the Blue Ridge and has been impacting IAD/DCA. This activity is expected to progress off toward the south and east over the next couple hours. Another potential round of storms could occur as storms form further west over WV and then spread eastward into this evening. Any thunderstorms should winds down this evening as a cold front moves through and drier air starts to work in from the northwest. VFR conditions and dry weather are expected on Saturday, with winds generally light out of the west to northwest. Prevailing VFR conditions are expected again on Sunday, but an additional round of thunderstorms may be possible during the afternoon and evening hours. Winds will generally be out of the south to southwest outside of any thunderstorms. Mid level broken to overcast clouds are favored over all terminals Monday through Wednesday of next week. At this time, cloud decks are likely to be VFR, but some lower clouds will be possible at times. && .MARINE... Winds have turned to out of the west across northern portions of the Bay and the Upper Tidal Potomac. Gusts to around 20 knots have been occurring in those locations, so Small Craft Advisories have been issued through this evening. SMWs may be needed over the waters late this afternoon into this evening as storms move over the waters. Storms should progress off to the south and east by late this evening, bringing the threat for SMWs to an end. Winds shift to out of the northwest behind a cold front later tonight. Light and variable winds are expected over the waters tomorrow. Winds turn out of the south on Sunday. SCAs will likely be needed within southerly flow during the day on Sunday. SMWs may also potentially be needed as thunderstorms move over the waters Sunday afternoon into Sunday evening. SubSCA conditions are most likely Monday and Tuesday. && .CLIMATE... Temperatures are expected to soar to as much as 15 to 20 degrees above average today. This approaches or exceeds daily record values at some sites. Below is a list of record daily high and warm low temperatures for today (June 12th). ================================================================= June 12th Record Daily Highs and Warm Lows ================================================================= Site Record High Record Warm Low DCA 95 F (set in 2017 +6 others) 77 F (set in 2015) IAD 96 F (set in 1986) 72 F (set in 1986) BWI 96 F (set in 1986 and 1914) 77 F (set in 1947) DMH 96 F (set in 2025 +2 others) 77 F (set in 2017 and 2015) NAK 98 F (set in 1914) 77 F (set in 2000 and 1973) HGR 92 F (set in 2017 +5 others) 71 F (set in 2010 +5 others) MRB 97 F (set in 1938 and 1933) 73 F (set in 1914) CHO 98 F (set in 1914) 72 F (set in 1947 +2 others) && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Heat Advisory until 8 PM EDT this evening for DCZ001. MD...Heat Advisory until 8 PM EDT this evening for MDZ003>006-008- 011-013-014-016>018-503>508. Small Craft Advisory until 10 PM EDT this evening for MDZ008. VA...Heat Advisory until 8 PM EDT this evening for VAZ025>031- 036>040-050-051-053>057-501-502-505-506-526-527. WV...Heat Advisory until 8 PM EDT this evening for WVZ051>053. MARINE...Heat Advisory until 8 PM EDT this evening for ANZ530. Small Craft Advisory until 10 PM EDT this evening for ANZ530- 531-535-538-539. && $$ DISCUSSION...KJP/JMG AVIATION...KJP/JMG MARINE...KJP/JMG