####018006564#### FXUS64 KHUN 170000 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 700 PM CDT Fri May 16 2025 ...New AVIATION... .NEAR TERM... (Tonight) Issued at 157 PM CDT Fri May 16 2025 Both low and mid cloud cover has thinned significantly over the last few hours east of the I-65 corridor. Further west, thicker mid/high cloud cover has redeveloped. Most locations have reached the lower to mid 80s across northern Alabama and southern middle Tennessee. Still could see an upper 80 degree high near the I-65 corridor and mid 80s further east. A very humid and unstable airmass (3000 to 4000 J/KG) is in place. However, The good news is that there have been very little signs of convective development a few models were hinting could happen around 4 PM. The cap in place aloft and the drier air between 850 mb and 700 mb seen in 7 AM Birmingham sounding, looks like they will hold off any convection this afternoon. Both satellite and radar trends seem to support this as well. Models still show the main upper level forcing sagging southeast into southern middle Tennessee and NW Alabama between 10 PM and 1 AM ahead of an approaching cold front. Enough MUCAPE or SBCAPE (1000 - 2000 J/KG) lingers ahead of the front into the overnight hours. However, strong shear continues to be shown ahead of the front and 0-3 km helicity climbs to between 200 and 350 m2/s2 as the best forcing moves into the area ahead of and with the front. Expect there could be some embedded supercells (producing large hail initially) that move into the area. Still thinking this will form into a more widespread damaging wind threat with a few tornadoes possible. The high low level moisture and cloudy conditions tonight should keep lows very warm, only dropping into the 65 to 70 degree range in most areas. Overall timing of convective initiation hasn't changed much. 1. Franklin (AL) NW Lincoln County (TN) - 10 PM to 2 AM 2. SW Lawrence County (AL) to Sewanee (TN) - Midnight to 3 AM 3. SE Cullman County (AL) to Fort Payne (AL) - 2 AM to 5 AM If some convection does eventually form 4 PM to 8 PM (as those few models were hinting), supercells and a larger hail/stronger tornado threat could exist during that period. At this time, that is not expected to occur. && .SHORT TERM... (Saturday through Monday) Issued at 157 PM CDT Fri May 16 2025 Much drier air moves southeast into the area just after daybreak on Saturday between 8 or 9 AM. The front should be far enough south to keep rain chances out of the forecast by then. Highs should reach the mid to upper 80s again across northern Alabama and southern middle Tennessee on Saturday. Most guidance places the front somewhere through central Alabama when it stalls. However, during the late afternoon/early evening hours, several models move this front northward into northwestern Alabama and then further northeast overnight. Scattered showers and thunderstorms in the evening should give way to more widespread activity overnight. Strong shear pushes back into the area and with very moist low level moisture moving back into the area behind the front, instability will increase enough to warrant at least a low severe threat. Main threats would be damaging winds and up to one inch hail. High dewpoints and cloudy conditions tonight should keep lows very warm, only dropping into the 65 to 70 degree range in most areas. As the front stalls near the southern portion of the forecast area, cloud conditions and additional showers and thunderstorms are expected on and off through the day into the early evening hours on Sunday. Expect cooler conditions as well with highs only climbing into the upper 70s to lower 80s. Again with strong shear over the area and enough instability in place, a few strong to marginally severe storms could occur. && .LONG TERM... (Sunday night through Friday) Issued at 157 PM CDT Fri May 16 2025 Luckily, it looks like we see a break in high rain/thunder chances Sunday night into Monday, as the front really pushes to the north as a stronger warm front. At the same time, upper level ridging builds over the area. Locations north of the Tennessee River could still see scattered showers and thunderstorms, possibly a few again strong to marginally severe. Highs will likely be similar (though current guidance may be a tad too low), reaching the mid to upper 80s. Monday night will still be very humid with lows dropping into the mid to upper 60s. A stronger storm system over the Rockies develops and moves slowly east Monday night into Tuesday. The strength of the upper level ridging and the northward placement of its associated warm front should keep any shower or thunderstorm activity north of the area Monday night. However, on Tuesday into Tuesday night, it looks like higher rain and thunderstorm chances move back into the region. Strong shear and instability will return ahead of that system. A bit more helicity is hinted at with model guidance. So tornadoes may be more of a threat with this system. However, it is still several days out, so alot can change. Again colder air moves into behind this system, towards the end of next week. && .AVIATION... (00Z TAFS) Issued at 700 PM CDT Fri May 16 2025 The primary feature of concern for aviation interests this evening and throughout the early morning hours on Sat will be one (or perhaps two) lines of SHRA/TSRA which may evolve from individual cells (currently developing within a zone from southeastern MO into west-central AR). Although it is still unclear how this will unfold, timing of potential storm impacts (including AWWs) at the terminals appears to be from 4-8Z/MSL and 6-10Z/HSV, and TEMPO groups have been included for these timeframes. Due to the existence of a strong low-level jet, LLWS has also been included thru 8-10Z Saturday. Outside of convection, conds will remain VFR, with a bkn-ovc coverage of mid/high-lvl clouds this evening/overnight and more scattered coverage tomorrow. Gusty SW sfc flow will veer to WSW and diminish in the wake of the nocturnal convective lines. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...KTW SHORT TERM...KTW LONG TERM...KTW AVIATION...70/DD ####018006774#### FXUS61 KBGM 170001 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 801 PM EDT Fri May 16 2025 .SYNOPSIS... Unsettled weather with a few rounds of showers and occasional thunder will persist through Saturday. Cooler weather with a few lingering showers is anticipated for Sunday. Drier, mostly sunny but cool weather is then expected heading into early next week. Another low pressure system looks to bring additional rain chances by middle to latter portion of next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... 600 PM Update... Axis of scattered showers and isolated thunderstorms, has finally generated just east of Utica-Ithaca- Elmira. Convection- Allowing Models (CAMS) were able to identify that boundary, which is basically a cold frontal segment which then reverses to a warm front in central to west-central Pennsylvania. That cold front segment will continue to carry east the next few hours, with 1000-1500 J/Kg of mixed layer Convective Available Potential Energy (CAPE). That will be adequate for the activity to persist. Though shear is pretty limited, model soundings have an inverted-V look to them which would promote good mixing down of downdrafts. Mesoanalysis Downdraft CAPE values are in the many hundreds to near 1000 J/Kg, so if the cells can get any more robust, we will have to monitor for gusty winds. Things should wind down by 10 PM, though showers-embedded thunder cannot totally be ruled out overnight as the frontal boundary kinks back north as a warm front. Previous discussion... After this morning's widespread showers and thunderstorms, the atmosphere has had a difficult time destabilizing, despite some breaks of sunshine this afternoon. The majority of the convection is located well south of the area (mainly across Central PA to the Mid-Atlantic coast). There is still some elevated instability across the area, but with mid-level dry air inhibiting convective initiation, coverage of showers and thunderstorms later this afternoon into this evening is not expected to be widespread and the threat for severe thunderstorms is lowering, but not totally gone. Tonight, scattered showers and thunderstorms are expected to continue (at least in the evening) with some elevated instability present. However, lapse rates will be weakening, which will limit any severe thunderstorm potential. Coverage of showers will likely diminish towards the second half of the night. It will remain mild and humid with lows in the upper 50s to lower 60s. While there is still a potential for strong to severe thunderstorms on Saturday, the overall potential is decreasing and therefore most of our region is now in a "Marginal Risk" for severe thunderstorms, rather than a "Slight Risk." This is due to relatively poor instability and lapse rates. There will be slightly higher lapse rates across our far eastern areas (Catskills-Mohawk Valley), so this is where the best chance for severe thunderstorms will be. That being said, it is looking more likely that most of the severe thunderstorms will be located well north and east of our area, more across New England. Otherwise, skies will be partly sunny on Saturday with highs in the lower 70s to near 80. Flow becomes more westerly behind the cold front Saturday night, which will result in some wrap-around/cold air advection showers, mainly across the Finger Lakes Region. Otherwise, it will become much cooler with lows in the mid 40s to lower 50s. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... 230 PM Update... Unsettled conditions will continue on Sunday with scattered showers as upper level low slowly exits to the northeast. Cool northwest flow on the backside of the low will make for a chilly and blustery day for mid May, with highs on Sunday only in the mid 50s to low 60s. As this system moves east of the region Sunday night, northwest flow will continue to advect cool air southward, however, ridging ridging aloft will also be building in, so the showers will be coming to an end. Lows on Sunday night will be in the low 40s for most of the region and a few of the coldest spots may drop into the upper 30s. && .LONG TERM /MONDAY THROUGH FRIDAY/... 230 PM Update... Dry but cool conditions are in store for next week as a ridge of high pressure builds into the region, and cool northwest flow remains overhead. Temperatures will be below normal throughout the long term period. Winds will remain breezy Monday as with a tight pressure gradient as high pressure builds in. Patchy frost will be possible Monday night/early Tuesday morning as temperatures plummet under mostly clear skies and calming winds. Dry conditions will continue through at least Tuesday as guidance has slowed down the arrival of the next system. Another upper level low will move into the Great Lakes region Wednesday with a surface low developing off the Mid Atlantic Coast. This system will bring widespread rain to the region Wednesday and Wednesday night with rain then continuing Thursday. It is interesting that the GFS is showing T850 below 0C Wednesday night and T850 below -2C Thursday night into Friday. Still a long ways out, but most of the models and ensembles are in agreement for another cold upper low for the end of the long term period, so at least expecting above average precipitation and below average temperatures as we head into Memorial Day weekend. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Mainly VFR conditions are expected this evening, although isolated showers and thunderstorms are possible mainly at AVP over the next hour or so. Brief MVFR conditions are possible as these showers move through. Conditions are expected to return to VFR tonight and remain that way through most of the rest of the current TAF period. Another round of showers and thunderstorms will be possible tomorrow afternoon, but confidence was not high enough at this time to include thunder in the TAFs. Outlook... Saturday afternoon...Scattered showers and thunderstorms may result in brief restrictions. Sunday...Scattered rain showers possible, especially at the Central NY terminals, which may result in occasional restrictions. Sunday night through Tuesday...Mainly VFR expected. Wednesday...Restrictions likely with rain showers. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...BJG/MDP NEAR TERM...BJG/MDP SHORT TERM...MPK LONG TERM...MPK AVIATION...BJG/ES ####018009453#### FXUS61 KALY 170002 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 802 PM EDT Fri May 16 2025 .SYNOPSIS... Scattered showers and and isolated thunderstorms this evening diminish overnight, but additional showers and thunderstorms, some strong to severe, are expected again tomorrow ahead of a cold front. We may still have some lingering showers around Sunday, but should dry out Monday through the middle of the week with much cooler weather behind the front. Rain chances increase towards the middle of next week, with continued below normal temperatures. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... As of 730pm, overall storm and shower activity late this afternoon into the early evening hours has been isolated with just a few storms developing in southern VT and the Upper Hudson Valley with a few more weak storms heading into the far western Mohawk Valley. Given radar and satellite trends and latest CAM guidance (especially the HRRR which seems to be handling things the best) we have trended POPs downward to just slight chance and low end chance through tonight. Storm coverage should remain isolated to widely scattered as overall forcing is nebulous in the form of very weak sfc boundaries/convergence. While dew points remain high enough to maintain the humid air mass, the probability for storms to become severe is diminishing and turning more unlikely as we head further into the evening hours/past peak heating. Previous discussion...Tonight, diffluent flow aloft and low- level warm advection will lead to plenty of clouds around tonight and a few lingering showers. A couple non-severe thunderstorms will also be possible overnight with some pockets of elevated instability. Lows will be quite mild, mainly in the 50s to 60s. Some patchy fog and low stratus are expected across the Mid Hudson Valley and southwestern New England due to light low-level S/SE flow, with some additional patchy fog for areas that receive rain this evening. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Key Message: - There is a slight risk for severe thunderstorms Saturday from late morning through mid to late afternoon for much of eastern NY and western New England. - The slight risk for severe weather has been shifted further north and east from the previous forecast. Discussion: Tomorrow, the upper low and occluded low track eastwards across the Great Lakes region. A weak warm frontal boundary lifts northwards late tonight/very early tomorrow morning, and there could be some lingering isolated showers/storms across northern areas tomorrow morning. However, additional showers and thunderstorms are expected to develop by mid to late morning as a pre-frontal trough tracks through the region. Some of these storms could become strong to severe (more below). There may be a brief lull in convective activity for a few hours in the mid to late afternoon, before another line of storms tracks from west to east across the region ahead of the system's actual cold front. Despite strong forcing for ascent, instability should diminish behind the first wave of convection, so the probability for severe weather with this second round of convection looks lower at this time. This is a change from the previous forecast, which messaged a greater severe potential with the second round of convection later in the day. Regarding the severe threat, timing appears to be from roughly 10 AM to 4PM tomorrow. There is some uncertainty in how much instability develops, but the HREF suggests that 1000-1500+ J/kg of SBCAPE is possible, with the greatest instability in the Hudson Valley from the Capital District northwards. This instability will overlap with 35-40+ kt of deep-layer wind shear. Damaging wind seems to be the primary threat with DCAPE values of 700-1000 J/kg, but large hail will also be possible with WBZ heights near 9.5 - 10.5 kft and mid-level lapse rates of 6.5-7C/km. There is also a chance for an isolated tornado or two tomorrow with some low-level curvature to the hodographs and low LCLs, although the fact that most of the wind shear is above the lowest 1 km makes this a lower-end threat. The threat appears greatest from roughly the Capital District north and east tomorrow, and given this we have collaborated with SPC and WFO BTV to have the slight risk moved into this area and trimmed back across the southern part of our area where forcing looks weaker. Instability should diminish behind this first round of convection, reducing the severe threat later in the evening. However, wind shear still looks impressive tomorrow afternoon and evening, so we can't totally rule out a stronger storm or two with the second round of convection if there is more instability than forecast. There is also a threat for heavy rain with any thunderstorms tomorrow, as PWAT values remain elevated at between 1.2-1.4" per the latest HREF. However, storm motions will be faster with strengthening flow aloft, and areas north of the I-90 that are expected to see the greatest convective coverage have received very little rain over the past 5 days. This should limit the threat for hydro issues, although any storms moving over urban/poor drainage areas could still result in some ponding of water. WPC has placed areas north of I-90 in a marginal risk ERO tomorrow. Highs will be mainly in the 70s to around 80, and it will be muggy again with dew points in the 50s to mid 60s. Saturday night through Sunday night...The cold front tracks through the region Saturday evening and early overnight. Convection comes to an end within a couple hours of sunset, and a much cooler airmass will infiltrate the region behind the front. There will be some scattered showers lingering, especially during the day on Sunday, with the upper low and associated cold pool aloft tracking across upstate NY. It will be much cooler with overnight lows in the 40s to 50s Saturday night and 30s to 40s Sunday night. Daytime highs Sunday will be mainly in the 50s to 60s with lower humidity. West winds also become breezy with the surface low tracking to our northeast and broad high pressure building out of Canada towards the Great Lakes. && .LONG TERM /MONDAY THROUGH FRIDAY/... Monday through Tuesday night...The upper low moves off to our northeast, but we remain in persistent NW flow aloft. High pressure remains northwest of our region, which will keep breezy conditions around through this timeframe. Temperatures remain below normal for this timeframe, with 50s to 60s during the day and 30s to 40s each night for lows. There could be a few lingering showers across the ADKs or southern Greens, but by and large most areas will remain dry. Wednesday through Friday...Chances for rain increase for the middle of the week, as guidance is in relatively good agreement on an upper shortwave tracking across the TN valley interacting with retrograding northern stream energy, eventually forming a closed upper low. At the surface, an area of low pressure will likely develop and track near the east coast, so we have included likely PoPs for Wednesday and Thursday. The details and timing will still need to be ironed out, including how quickly the upper low and lingering precip depart to our east Thursday night and Friday. Nevertheless, with a storm track to our south and east, we will likely see continued below normal temperatures each day. CPC is expecting below normal temperatures and above normal precip to continue for days 8-14. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR conditions early this evening outside of possible showers/thunderstorms which may impact KALB between 01Z-03Z/Sat. MVFR/IFR Cigs are then expected to develop between 03Z-06Z/Sat and persist until 12Z-15Z/Sat. Several bands of showers/thunderstorms are expected to pass across the TAF sites from west to east during Saturday, with the most likely times between 15Z-19Z, then another period between 21Z-24Z/Sat. Brief MVFR/IFR conditions (mainly Vsbys) will occur within any passing showers/storms. South to southeast winds 4-8 KT tonight will increase to 8-12 KT Saturday morning with a few gusts of 20-25 KT possible. Winds will shift into the southwest to west Saturday afternoon at similar speeds. Winds will be stronger, and variable in direction in and near any thunderstorms. Outlook... Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Sunday: High Operational Impact. Windy With Gusts To 30 kts. Likely SHRA. Sunday Night: Low Operational Impact. Breezy. Slight Chance of SHRA. Monday: Low Operational Impact. Breezy. NO SIG WX. Monday Night: Low Operational Impact. Breezy. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: Moderate Operational Impact. Chance of SHRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Main NEAR TERM...Speciale SHORT TERM...Main LONG TERM...Main AVIATION...KL ####018009246#### FXUS61 KPHI 170003 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 803 PM EDT Fri May 16 2025 .SYNOPSIS... Periods of showers, thunderstorms, and humidity continue through Saturday morning ahead of a strong cold front that passes through Saturday afternoon into Saturday evening. High pressure builds into the area on Sunday and persists into Tuesday before another period of unsettled weather returns Wednesday into Thursday. && .NEAR TERM /THROUGH SATURDAY/... 8 PM update... Severe Thunderstorm Watch cancelled now that convection has either dissipated or is moving off the coast. Guidance continues to indicate some scattered late night/early morning showers and thunderstorms, but odds favor limited if any severe/flood threat from this activity. 530 PM update... Severe Thunderstorm Watch in effect for central and southern areas as next incoming MCS moving toward region presently. Severe warnings may be imminent for southern areas, though uncertainty about how far north and east activity can maintain strength given how well worked over the atmosphere was and because we're about to lose daylight. 4PM discussion... A second round of severe weather is possible late this afternoon and into tonight as another MCS moves east from the southern Ohio River Valley across Virginia and into the DC Metro. This MCS is expected to bring a cluster of storms across the Delmarva tonight, potentially impacting portions of southeast PA and southern NJ again. This MCS also looks to interact with the residual outflow boundary from our severe storms late this morning and early this afternoon. In fact, convection has fired up along this outflow boundary already across central PA. There remains ample untapped instability (2000-3000 J/kg CAPE) across south central PA, northern VA, and the western Delmarva Peninsula. Furthermore, skies have cleared out rapidly this afternoon, allowing for some locations to see some atmospheric destabilization again. Damaging wind gusts with some possible hail will be the main concerns, but another tornado or two cannot be ruled out with this second round of severe storms. The second round of severe potential will be around 5-9pm. Overnight, there may still be some convection ongoing into the evening but this should diminish with time leading to another brief lull. Once again, there could be some low clouds, mist, and fog that form due to the continuing moist environment. The action won't be over though because another decaying MCS may move into the area sometime overnight into early Saturday morning. There remains a lot of uncertainty on this though and depends on how storms pan out across Missouri and Kentucky tonight. Otherwise, it will be a mild, muggy night with lows mainly in the 60s. The aforementioned MCS arrives across the region around daybreak. A bit of uncertainty still remains with how strong this MCS will remain by the time it reaches the Delaware Valley, but the chance for showers and storms certainly remains possible. Skies should be partly to mostly cloudy through the morning however, before clearing out by early afternoon. Temperatures will climb into the 80s for most areas with dew points in the low to mid 60s making it feel quite uncomfortable outside. The cold front will continue to make its way east through the afternoon where isolated to scattered thunderstorms will re-develop by the afternoon. That said, the latest guidance is less aggressive with storm development Saturday afternoon. While some instability will be around, upper level forcing will be weaker and drier air aloft may limit any widespread convective initiation. As of now, storms tomorrow will likely be more isolated to scattered in nature with a marginal chance for storms to become severe. If so, gusty winds and hail will be the main concern. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... The cold front will push off the coast by Saturday night and the threat for storms wanes in addition to the loss of daytime heating. Nighttime lows will be in the mid 50s to low 60s. Sunday is looking like the better half of the weekend as tranquil weather returns with the upper trough moving further east. Partly to mostly cloudy skies are expected with dry conditions and lower humidity. Perhaps an isolated shower is possible north and west, but general thinking is most of the area will stay dry. The one thing to note is winds will increase as diurnal mixing occurs as the area lies wedged between systems resulting in a tightening pressure gradient. Wind gusts up 30-35 mph will be possible. Gusts will diminish into Sunday night under mostly clear skies. Despite the windy conditions, high temperatures should mainly be in the 70s (with 60s in the Poconos). && .LONG TERM /MONDAY THROUGH FRIDAY/... By Monday, low pressure over the Canadian Maritimes will begin to move further east into the North Atlantic. At the same time, high pressure will settle over the Mid-Atlantic before moving offshore on Tuesday. Aloft, the area will be situated under northwest flow in wake of exiting upper trough. All in all, a tranquil weather period is in store with mostly clear skies, light winds and dry weather. By Tuesday night and through the middle of the week, our attention will turn to our next weather system which will take aim at the area. Global and ensemble guidance both feature a deep upper trough moving into the Great Lakes/Northeast region around the middle of the week with a potential coastal low developing before moving up towards New England. This would indicate another period of unsettled weather with periods of rain starting as early as Tuesday night, and more so on Wednesday and Thursday. Still quite a ways out from this potential, so have generally stuck with NBM guidance and capped rain chances at chance (~30-50%). In terms of temperatures, we'll encounter temperatures around average on Monday, before dipping below average for Tuesday through Thursday as the area remains situated within the deep upper trough. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...Evening showers/storms are moving out already this evening, but the potential for low cigs and low visbys once again due to stratus, mist and fog remains. However, atmosphere was cleansed fairly well by earlier convection, so guidance has backed off on the low cig/vsby threat somewhat. More showers and storms could move in late tonight, however. S to SW winds around 5 knots. Low confidence. Saturday...Sub VFR conditions possible early in the morning with showers and storms around. Otherwise, primarily VFR expected. Very isolated to showers and thunderstorms possible in the afternoon and early evening. Winds WSW around 10-15 kts with gusts to 20 kts. Low confidence on showers and storms in the morning and even lower confidence on activity in the afternoon; moderate confidence otherwise. Outlook... Saturday night...VFR. Winds W to WNW 10 kts or less. Sunday through Tuesday...VFR. Gusty winds up to 25-30 kt possible on Sunday. Otherwise, no significant weather expected. && .MARINE... Generally sub SCA except storms tonight into early Saturday morning could produce locally strong winds. A few isolated showers and storms possible Saturday afternoon. SW winds gust to around 15-20 kts in the afternoon, but no headlines expected. Outlook... Saturday night...No marine headlines expected. Sunday through Sunday night...SCA conditions possible due to wind gusts up to 25 kt. Monday through Tuesday...No marine headlines expected. Rip current... Currently projecting low risk of rip currents over the weekend based on low wave heights of 1-2 feet and winds shifting offshore at 10-15 mph. && .TIDES/COASTAL FLOODING... The Coastal Flood Advisory for northwestern Burlington and lower Bucks Counties has been extended until 8 AM Saturday. Minor coastal flooding is expected with the early morning high tide this morning and on Saturday. It's possible minor coastal flooding may occur on Sunday as well, where further extensions may be needed. For areas of the lower tidal Delaware River near Philadelphia may encounter spotty minor coastal flooding through Saturday, but should fall short of advisory levels. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Coastal Flood Advisory until 8 AM EDT Saturday for PAZ106. NJ...Coastal Flood Advisory until 8 AM EDT Saturday for NJZ019. DE...None. MD...None. MARINE...None. && $$ SYNOPSIS...MJL NEAR TERM...Fitzsimmons/MJL/RCM SHORT TERM...DeSilva LONG TERM...DeSilva AVIATION...DeSilva/Fitzsimmons/RCM MARINE...DeSilva/Fitzsimmons/RCM TIDES/COASTAL FLOODING... ####018006839#### FXUS65 KPSR 170003 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 503 PM MST Fri May 16 2025 .UPDATE...Updated 00z Aviation Discussion. && .Key Messages... 1) Gusty winds over the weekend resulting targeted advisories and locally elevated fire danger 2) Substantial warming trend latter half of next week resulting in widespread moderate HeatRisk .DISCUSSION... Weather Pattern Overview: Broadly cyclonic flow continues over the SW Conus with a subtle, but otherwise innocuous shortwave ejecting over northern Mexico early this afternoon. However, WV imagery shows a robust upstream jet core with a strong vorticity center nearing the Pacific NW poised to buckle the flow pattern and create deep negative height anomalies over the Great Basin this weekend. Height falls will begin to impact the CWA Saturday with the leading jet max cresting the coastal range during an extremely favorable afternoon time frame for downsloping winds and mountain rotors. In fact, GFS BUFR soundings continue to suggest 40-50kt compressed in the sfc-H9 layer surging down the leeward side of the San Diego mountains Saturday evening where advisories currently exist. However, with the initial shortwave already ejecting towards the central high plains by Sunday morning and secession of height falls, the strongest advisory level winds should be rather short lived. Behind the first wave, a secondary robust negative PV anomaly will dig into the trough axis late Sunday and Monday acting to reinforce cooler tropospheric temperatures and a higher momentum airmass aloft. However, recent model trends are keeping bulk of energy confined to far northern Arizona; and without notable height falls, a reduced pressure/thermal gradient and proximity south of the jet core will keep wind speeds and gusts more muted than previous forecasts. Any modest moisture intrusion ahead of this system also appears reduced with only 4-5 g/kg mixing ratio nowhere near sufficient to achieve saturation under warmer midlevel thermal profiles located on the anti-cyclonic side of the jet core. Given the trend in evolution, temperature forecasts are not nearly as cool as previous iterations, yet still around 5F below normal during the first part of next week. With the downstream flow pattern briefly progressive and re- orienting into a renewed blocking configuration, the entire trough structure will dislodge into the plains by the middle of the week resulting in pronounced height rises and longwave ridging becoming established over the SW Conus. Ensemble mean forecasts suggest H5 heights reaching at least 586dm during the latter half of the week with some of the more aggressive members still around 590dm peak heights. Nevertheless, massive downstream blocking over the eastern Conus and Atlantic basin will ensure a stagnant pattern and some manner of ridging stuck over the forecast area. There are some ensemble members attempting to realign the blocking pattern and erode the ridge axis with Pacific flow by the end of next week, however these type of blocking patterns typically take longer than models indicate to break down. Regardless, rather widespread moderate HeatRisk should take hold of the area towards the end of next week with temperatures nearly 10F above normal. Forecast Confidence & Deviations: Confidence in temperature forecasts remains very good through the weekend with somewhat lower confidence early next week, albeit improving given the consolidating trend among modeling suites keeping shortwave energy further to the north. Should this system end up digging farther south, temperatures would be a few degrees cooler than current forecasts while winds early next week could be somewhat stronger. With a very favorable pattern, have continued to increase wind speeds Saturday afternoon and evening over the automated NBM. Forecast confidence for hotter temperatures during the latter half of the forecast period remains good, but some adjustments to these readings (maybe a 1F-3F higher) may eventually occur, especially over the Memorial Day weekend depending on the pattern evolution. && .AVIATION...Updated at 0000Z. South Central Arizona including KPHX, KIWA, KSDL, KDVT: Only minor aviation concerns will exist during the TAF period under occasional FEW-SCT high clouds. Winds will maintain a westerly component through much of the evening and shift SE by 07-09Z. Mid morning Saturday, winds will begin to veer from SE to S, creating a light (AOB 10 kts) southerly cross-runway component at KPHX and KDVT, and a light southwesterly crosswind at KIWA late morning/midday. By the afternoon (20-21Z), anticipate winds to establish a prevailing southwesterly direction, with gusts to around 15-20 kts developing. Southeast California/Southwest Arizona including KIPL and KBLH: Gusty southwest winds on Saturday will be the primary aviation concern during the TAF period under occasional FEW-SCT high clouds. Winds will shift from SE to WSW at KIPL within the next few hours and maintain WSW through the overnight hours. Winds at KBLH will favor SSW through much of the period, veering gradually out of the SW Saturday. Expect speeds to remain AOB 11 kts through approximately 15Z Saturday morning. Speeds will begin to pick up at both the terminals after that time, with southwesterly gusts to between 25-30 kts becoming common Saturday afternoon. && .FIRE WEATHER... Wind speeds will increase markedly Saturday with gusts 20-30 mph becoming common in the afternoon resulting in an elevated fire danger. MinRHs will fall into a 10-15% range Saturday across the eastern districts with readings across the western districts improving to 20-25%. Humidity levels will increase modestly Sunday precluding critical conditions despite heightened wind speeds. Overnight recovery will be fair to poor with readings between 20-30% over the eastern districts and 30-50% over the western districts with some improvement early next week. Very warm and dry weather will return during the middle of next week with minRH in the single digits following poor overnight recovery, however wind speeds will be much weaker as high pressure starts building into the region. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...Wind Advisory from 2 PM Saturday to 7 AM PDT Sunday for CAZ562. Wind Advisory from 4 PM Saturday to 2 AM PDT Sunday for CAZ563- 566-567. && $$ DISCUSSION...18/Kuhlman AVIATION...Whittock FIRE WEATHER...18/Kuhlman