####018001941#### FXUS63 KBIS 101926 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 226 PM CDT Fri May 10 2024 .KEY MESSAGES... - Warm temperatures continue through the weekend. Dry conditions expected for Saturday, with an isolated shower or thunderstorm possible on Sunday. - Average (mid to upper 60s) temperatures expected next week, as well as near daily chances for showers and thunderstorms. && .DISCUSSION... Issued at 225 PM CDT Fri May 10 2024 Strong northwest flow aloft across the Northern Plains with a clipper/S/WV embedded trough moving southeast across the Upper Midwest. Outside of some diurnally drive CU, a mostly sunny sky prevails with very comfortable temperatures in the 60s to lower 70s. Our flow aloft remain northwesterly over the next couple of days, with an embedded wave moving through later this weekend bringing a chance for showers and perhaps a few thunderstorms Sat night through Sunday. Model ensembles for next week still show a zonal flow pattern, with increasing probability of decent S/WV moving through the region Tue-Wed, increasing the chances for showers/thunderstorms. Along with this, temperatures will trend slightly cooler with and in the wake of this wave, but then should rebound some with upper level ridging favored west. How much we warm and also precipitation chances remain uncertain as the ridge will be just to our west and much will depend how far east the transition zone moves. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 121 PM CDT Fri May 10 2024 VFR conditions expected through the 18Z forecast period. Mainly clear skies are expected today, with periods of high clouds and a few afternoon fair weather cumulus clouds. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...NH AVIATION...NH ####018005244#### FXUS61 KCTP 101928 AFDCTP Area Forecast Discussion National Weather Service State College PA 328 PM EDT Fri May 10 2024 .SYNOPSIS... Upper level troughing will remain over Pennsylvania through this weekend with shortwaves tracking over the state and focusing rainfall today and Saturday night into early Sunday. The upper trough will lift out early next week, then a cold front will likely push through Tuesday. A wave of low pressure is likely to track south of Pennsylvania next Wednesday. && .NEAR TERM /UNTIL 11 PM THIS EVENING/... Regional radar mosaic this mid afternoon shows a well-defined low to mid level inverted trough and zone of enhanced FGEN forcing and quasi-stnry area of rain over the Central and Nrn Mtns of PA. This area of mainly MDT rain was embedded with a broader and very slowly dissipating area of lighter rain being supported by the nose of a -2 to -3 sigma easterly LLJ (deviation from the normal u-component of the wind at this time of year). This moisture laden llvl easterly flow will persist for the next 2-4 hours before the sfc-850 mb low slides off the Mid Atlantic Coast and causes the aforementioned N/S inverted trough to weaken and winds to back around to the north then northwest. This will help to accelerate the diminishing trend of the rain coverage and intensity, though we expect some lingering periods of light rain/drizzle through early tonight. Narrow ridging at the sfc and aloft will slide east across the region later tonight. Any clearing with this feature will be quite fleeting as the light wind, cool/moist air and wet ground quickly leads to patchy dense fog and reformation of stratus for 5-8 through the mid morning Saturday. Chilly temps for mid may with a tight range of only 5-6 deg F (ranging from the mid and upper 40s across the higher terrain of the North and West, to the low 50s in the Central and Southern Valleys of the state) will dip about 8-10 deg F for lows tonight between 40-45F. Additional rainfall amounts late this afternoon and evening will likely range from several hundredths of an inch in most places to locally around one quarter of an inch in some spots, especially across the Western Poconos where the aforementioned nose of the LLJ will linger the longest. && .SHORT TERM /11 PM THIS EVENING THROUGH SATURDAY NIGHT/... After the break from the rain tonight into early Saturday, expect a return of showers Saturday PM associated with height falls ahead of a potent upper level shortwave diving across the Grt Lks. Strong large scale forcing, in combination with some minimal model cape, supports high POPs with a tsra possible in spots during the afternoon. Moderate PWAT values indicate that rainfall Sat PM should not be significant, generally between 0.1 and 0.2 inches based on ensemble mean qpf. The upper trough is progged to cut off and track along the PA/NY border Sat night into Sunday morning. Low level instability associated with this feature should result in plenty of cloud cover and at least scattered showers lasting into early Sunday. Brightening skies and diminishing showers look likely by Sunday afternoon, as the upper trough exits the state and surface surface ridging builds in from the west. Mixing down progged 850mb temps of around 4C translates to expected highs in the low to mid 60s over much of the forecast area, with upper 50s over the higher terrain of Eastern PA. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Tendency to have a large scale upper level ridge over the west this weekend, will result in much below normal 500 mb heights over the east into next week. While some milder and drier conditions will be possible Monday into Tuesday, much of the time it will be cooler than normal and wet from time to time for much of the upcoming week. Sunday will be one day that will feature gusty winds and cold temperatures. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... Widespread rain across central Pennsylvania will continue to impact cigs and vsbys, keeping them mainly in the upper IFR to MVFR range through early tonight. As the llvl wind backs from the east through the north and to the northwest, cigs will ocnly dip into the LIFR range with ocnl IFR vsbys at KJST and KBFD. We'll likely get a small break from the rain after 00Z Saturday before the next trough is progged to swing through Saturday afternoon. The break in the cloud cover, very light wind and moist ground will lead to at least patchy dense fog with LIFR to VLIFR possible at all central PA airfields late tonight through about 12 or 13Z Sat. Outlook... Sat...PM showers/low cigs possible, mainly W Mtns. Sun...AM low cigs possible W Mtns. Sct afternoon showers/brief vis reductions possible. Mon...AM dry and mainly VFR. Showers return PM. Tue...Showers and tstms. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Steinbugl AVIATION...Lambert ####018009445#### FXUS61 KPHI 101928 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 328 PM EDT Fri May 10 2024 .SYNOPSIS... A wave of low pressure offshore moves away overnight. Weak high pressure arrives for Saturday before another low moves through Saturday night and Sunday. High pressure builds south of the Mid-Atlantic region Sunday night into Monday. Another area of low pressure may affect the area with more unsettled weather by the middle of next week. && .NEAR TERM /THROUGH SATURDAY/... The offshore low will continue to move away tonight and the upper trough to the west will swing through overnight. Until that happens, occasional showers and low clouds will be across the area. As drier air arrives aloft, the precipitation may end as some drizzle overnight. Fog is possible too if breaks develop in the overcast. We'll taper pops down from W to E overnight and mention patchy fog in the fcst. The exact details of the overnight improvement are not certain attm. By morning, lows will drop into the low 40s up across the N/W areas while mid/upper 40s will be for the other areas. Winds will decrease and remain Northwest to East at 5 to 10 mph. For Saturday, a more tranquil weather day is expected with weak high pressure building in. There may still be some low clouds or fog across the area early, but thru the morning partly sunny skies will develop across most areas. By afternoon, the sun will mix with clouds at times. A couple showers may spill over the western areas by late afternoon. High temperatures will be below normal with high only in the low/mid 60s for most spots. Highs in the 50s will be across the higher elevations of the Poconos. Winds will be Northeast at 5 to 10 mph. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... A digging trough moving through the Great Lakes and an associated wave of low pressure at the surface will approach and push through Saturday Night into Sunday. Expecting more rain and a relatively dreary Sunday. Some elevated instability works in, especially over Delmarva, so can't rule out a rumble of thunder, though not expecting any severe weather. Rainfall amounts from a tenth to a half an inch are expected, with areas north and west of the Philadelphia metro getting into the upper end of that spectrum. It will be quite raw out with periods of rain and temperatures in the upper 50s/low 60s for Mother's Day. We begin to dry out on Sunday Night as the trough moves offshore and ridging builds in from the west. Expecting a spread of 40s for overnight lows to close out the weekend. A nice start to the week is expected with a broad area of high pressure working in. Temperatures moderate back to near-normal levels for mid-May, with low to mid 70s expected for most. The exception being the southern Poconos and along the coast, where highs will stay in the 60s. Skies will be mostly sunny with some passing clouds at times. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Long term period will be marked by a couple systems moving through over the work week, with temperatures hovering near normal for mid- May. Looking at some of the NAEFS ensemble probabilities and percentiles, the two main systems next week look rather unimpactful at this time, just bringing some rain to the region. Flooding and severe potential looks quite low currently. Ridging moves offshore Monday night with a shortwave moving across the Ohio Valley towards the Mid-Atlantic. An area of low pressure will take a similar track, eventually moving over or just south of the region on Tuesday Night. Rain chances increase by midday, with both deterministic and ensemble guidance showing the bulk of the rain coming in the overnight hours of Tuesday. There could be some embedded thunder as well. Showers could linger through the day on Wednesday but things try to turn drier Wednesday night into Thursday as a ridge builds in. The tranquil weather does not last for long as another system moves in for the end of the week. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas... thru the evening... Mostly MVFR conditions across the terminals so far early this afternoon. These conditions will probably not change much except for a few lower VSBYS in rain showers which are moving thru the area. East winds mostly around 10 knots with gusts around 20 knots at times, especially KACY. Medium confid. tonight... less certainty with regards to how things improve overnight. Not a strong push of dry air, but the low and trough will move away and rains/drizzle will end overnight. These will likely be fog at most terminals with the added moisture from todays rains. Any clearing could result in widespread fog. Light E/NE winds. Low confid overall. Saturday... Any lingering low clouds/fog early will diminish 12Z/13Z followed by VFR conditions. Clouds will increase during the afternoon. Light winds will become Southeast at 5 to 10 knots during the afternoon. Low/medium confid. Outlook... Saturday Night through Sunday Night...MVFR/IFR conditions expected with low ceilings and reduced visibility with periods of rain moving through. Monday through Monday Night..VFR. No significant weather. Tuesday...VFR to start but sub-VFR conditions likely (60-70%) later in the day as showers move in. Tuesday Night through Wednesday...Sub-VFR conditions expected with showers. Chance of thunderstorms (15-25%) Tuesday night into Wednesday. && .MARINE... We'll continue with the SCA flags for now. Winds will decrease this evening and the Delaware Bay will likely come down at 8PM if not before. The SCA for the ocean will continue into Saturday with seas remaining above 5 ft thru that period. Showers and then some drizzle overnight, Fog possible. Fair weather expected for Saturday. Outlook... Saturday Night through Monday...No marine headlines expected. Monday Night through Wednesday...SCA conditions possible (30-40%) as wind gusts get near 25 kt. Seas will get near 5 feet on Wednesday. && .TIDES/COASTAL FLOODING... The new moon occurred Tuesday, May 7th, and this is resulting in high astronomical tides. An onshore has developed and will remain thru tonight. While the astronomical tides will be gradually lowering as we get farther away from the new moon, the onshore will increase the surge values at least some. With the peak onshore flow leading up to tonight's high tide cycle, guidance continues to indicate the threat for moderate tidal flooding for portions of Atlantic coastal New Jersey and Delaware, as well as Delaware Bay with the high tide cycle tonight into early Saturday morning high tide cycle. With increased confidence of a long duration of moderate to strong onshore flow through the day today and water levels/surge values continuing to run high with the latest high tide cycle last night into early this morning, the Coastal Flood Warning for tonight's high tide has been expanded to include all areas previously covered by the Coastal Flood Watch. Spotty minor coastal flooding will occur with todays (lower) high tide today within the Warning area. Outside of the Warning area, in adjacent areas of the Atlantic coast of New Jersey, Delaware Bay, and the tidal Delaware River, another round of widespread minor coastal flooding is expected with the high tide cycle tonight into early Saturday morning. Therefore, another Coastal Flood Advisory has been issued for these areas for the tonight into early Saturday high tide cycle. The high tide cycle tonight looks to be the peak of the coastal flooding impacts area-wide, but additional minor coastal flooding is forecast with the evening/overnight high tide Saturday night into early Sunday. Flooding is not expected at this time for our Maryland zones along the Chesapeake through Saturday. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Coastal Flood Advisory from 2 AM to 7 AM EDT Saturday for PAZ070-071-106. NJ...Coastal Flood Advisory from midnight tonight to 4 AM EDT Saturday for NJZ016. Coastal Flood Warning from 8 PM this evening to 4 AM EDT Saturday for NJZ021>025. Coastal Flood Advisory from 9 PM this evening to 3 AM EDT Saturday for NJZ012>014. Coastal Flood Advisory from 2 AM to 7 AM EDT Saturday for NJZ017>019. Coastal Flood Warning until 4 AM EDT Saturday for NJZ020-026- 027. DE...Coastal Flood Advisory from midnight tonight to 4 AM EDT Saturday for DEZ001. Coastal Flood Warning from 8 PM this evening to 4 AM EDT Saturday for DEZ002>004. MD...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ430- 431. Small Craft Advisory until 6 PM EDT Saturday for ANZ450>455. && $$ SYNOPSIS...AKL/Fitzsimmons/OHara NEAR TERM...OHara SHORT TERM...Hoeflich LONG TERM...Hoeflich AVIATION...Hoeflich/OHara MARINE...Hoeflich/OHara TIDES/COASTAL FLOODING... ####018006059#### FXUS61 KCTP 101929 AFDCTP Area Forecast Discussion National Weather Service State College PA 329 PM EDT Fri May 10 2024 .SYNOPSIS... Upper level troughing will remain over Pennsylvania through this weekend with shortwaves tracking over the state and focusing rainfall today and Saturday night into early Sunday. The upper trough will lift out early next week, then a cold front will likely push through Tuesday. A wave of low pressure is likely to track south of Pennsylvania next Wednesday. && .NEAR TERM /UNTIL 11 PM THIS EVENING/... Regional radar mosaic this mid afternoon shows a well-defined low to mid level inverted trough and zone of enhanced FGEN forcing and quasi-stnry area of rain over the Central and Nrn Mtns of PA. This area of mainly MDT rain was embedded with a broader and very slowly dissipating area of lighter rain being supported by the nose of a -2 to -3 sigma easterly LLJ (deviation from the normal u-component of the wind at this time of year). This moisture laden llvl easterly flow will persist for the next 2-4 hours before the sfc-850 mb low slides off the Mid Atlantic Coast and causes the aforementioned N/S inverted trough to weaken and winds to back around to the north then northwest. This will help to accelerate the diminishing trend of the rain coverage and intensity, though we expect some lingering periods of light rain/drizzle through early tonight. Narrow ridging at the sfc and aloft will slide east across the region later tonight. Any clearing with this feature will be quite fleeting as the light wind, cool/moist air and wet ground quickly leads to patchy dense fog and reformation of stratus for 5-8 through the mid morning Saturday. Chilly temps for mid may with a tight range of only 5-6 deg F (ranging from the mid and upper 40s across the higher terrain of the North and West, to the low 50s in the Central and Southern Valleys of the state) will dip about 8-10 deg F for lows tonight between 40-45F. Additional rainfall amounts late this afternoon and evening will likely range from several hundredths of an inch in most places to locally around one quarter of an inch in some spots, especially across the Western Poconos where the aforementioned nose of the LLJ will linger the longest. && .SHORT TERM /11 PM THIS EVENING THROUGH SATURDAY NIGHT/... After the break from the rain tonight into early Saturday, expect a return of showers Saturday PM associated with height falls ahead of a potent upper level shortwave diving across the Grt Lks. Strong large scale forcing, in combination with some minimal model cape, supports high POPs with a tsra possible in spots during the afternoon. Moderate PWAT values indicate that rainfall Sat PM should not be significant, generally between 0.1 and 0.2 inches based on ensemble mean qpf. The upper trough is progged to cut off and track along the PA/NY border Sat night into Sunday morning. Low level instability associated with this feature should result in plenty of cloud cover and at least scattered showers lasting into early Sunday. Brightening skies and diminishing showers look likely by Sunday afternoon, as the upper trough exits the state and surface surface ridging builds in from the west. Mixing down progged 850mb temps of around 4C translates to expected highs in the low to mid 60s over much of the forecast area, with upper 50s over the higher terrain of Eastern PA. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Closed 500mb low moves across PA/NY border early Sunday followed by rising heights into early next week. This will translate into a seasonably cool and showery Mother's Day followed by a warmer and mainly dry start to next week. QPF will remain light given lack of deep moisture. Forecast daytime high temps on Sunday in the 55-65F range are 5-10F below early May climo. Max temps should rebound +10-20F on Monday aided by a milder SW flow. A cold front trailing low pressure in eastern Canada is fcst to stall out over the lower Great Lakes Monday and could trigger a shower or t-storm over the far NW mtns. Most of CPA should start the week rain-free. A southern stream wave and accompanying higher pwats are projected to link-up to bring rain Tue-Wed. Model and ensemble consensus favors another ridge building in behind this system into the second half of next week. The overall upper level pattern heading into next weekend looks rather blocky - which is typical for this time of year - but also results in much lower confidence/predictability. Some data suggest a cut-off low pressure system could bring a slight risk of heavy rainfall on 5/18 per the latest CPC 8-14 day hazards outlook. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... Widespread rain across central Pennsylvania will continue to impact cigs and vsbys, keeping them mainly in the upper IFR to MVFR range through early tonight. As the llvl wind backs from the east through the north and to the northwest, cigs will ocnly dip into the LIFR range with ocnl IFR vsbys at KJST and KBFD. We'll likely get a small break from the rain after 00Z Saturday before the next trough is progged to swing through Saturday afternoon. The break in the cloud cover, very light wind and moist ground will lead to at least patchy dense fog with LIFR to VLIFR possible at all central PA airfields late tonight through about 12 or 13Z Sat. Outlook... Sat...PM showers/low cigs possible, mainly W Mtns. Sun...AM low cigs possible W Mtns. Sct afternoon showers/brief vis reductions possible. Mon...AM dry and mainly VFR. Showers return PM. Tue...Showers and tstms. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert LONG TERM...Steinbugl AVIATION...Lambert