Area Forecast Discussion
Issued by NWS Albany, NY
Issued by NWS Albany, NY
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810 FXUS61 KALY 041735 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 135 PM EDT Thu Jul 4 2024 .SYNOPSIS... Warm and more humid conditions are expected for Independence Day today with some spotty showers or thunderstorms around. With a frontal boundary around, the threat for a shower or thunderstorm will linger into Friday, with continued warm and muggy conditions. Hot and humid conditions are expected on Saturday with more thunderstorms around once again. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Diffuse surface boundary across the region producing cloud cover and some isolated showers in the mid Hudson Valley and NW CT. A few more showers and an isolated thunderstorms is possible at maximum heating and instability this afternoon over those areas. Lots of sum elsewhere, with some convective clouds even into the Mohawk Valley, southern VT and the Berkshires, but more scattered with maybe a sprinkle. Just minor adjustments to rain chances, sky cover and temperatures through this afternoon. Highs today look to reach the mid to upper 80s in valley areas, with upper 70s to low 80s in the high terrain. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... Any convection should start to diminish after sunset this evening, allowing for mainly quiet conditions for tonight. It will be more humid than recent nights, so some patchy fog may developed in some typical sheltered areas. Otherwise, skies will be partly cloudy through the overnight with lows in the 60s. On Friday, a slow moving surface boundary will be near or just south of the area, but will be lifting northward as a warm front by later in the day and into Friday night. Meanwhile, the region will be under the influence of south to southwest flow aloft, with an upper level disturbance well west of the region over the Midwest. With plenty of warm temps in place aloft, it will be a rather hot day on Friday, with valley areas reaching into the upper 80s to low 90s. Dewpoints will continue to creep up through the 60s and may even reach into the low 70s for valley areas. This could allow heat index values to come close to 95 degrees by afternoon in some valley areas, so will need to watch this closely in case any heat advisories will be needed. Although the morning should be fairly dry, the warm and muggy air mass and nearby boundary could allow for some afternoon convection to develop. CAMs have different ideas regarding the exact placement and coverage of storms, but there will be the potential for some showers and t-storms to develop, especially for southern areas. With the warm temps aloft, lapse rates won`t be overly impressive, but there should be some instability in place (00z SPC HREF shows around 1000 J/kg by later in the day). Can`t totally rule out a stray severe storm due to precip loading, but the lack of upper level support and poor lapse rates should help prevent a more widespread threat for strong convection on Friday. Also, coverage of convection may be more isolated to scattered during the day on Friday. However, there may be more coverage around by the overnight hours as the frontal boundary lifts northward, although surface-based instability looks to be more limited during the overnight hours due to a nocturnal inversion in place near the surface. With higher PWATs in place, any storms on Friday night could contain heavy downpours, so a localized threat for ponding will be possible with any convection. It will be a mild and muggy night on Friday night with lows in the mid 60s to low 70s. On Saturday, upper level shortwave trough will be lifting from the Upper Great Lakes and across southern Canada. A weak surface cold front will be trying to push across the area from the west. Some additional convection is expected on Saturday, with the greatest coverage probably for eastern and southern areas and mainly earlier in the day. Models continue to have differing ideas regarding exact coverage/placement once again as well. There could be a localized severe threat on Saturday, but the best heights falls and upper level dynamics are pretty far off to the northwest. With PWATs around two inches, heavy downpours may be a bigger threat, depending on where storms form and if any training occurs. Otherwise, it will be another warm and very humid day (dewpoints well into the 70s possible) with heat index values nearing advisory criteria in valley areas. Behind the front, somewhat drier air tries to move in for Saturday night as dewpoints start to lower. The threat for showers/t-storms looks to lower on Sat night with lows back down into the 60s under a partly cloudy sky. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Dry conditions return for the start of the long term forecast period as surface high pressure approaches from the west and shortwave ridging builds in aloft. Saturday`s cold front will become positioned just to the south of the region as a diffuse, stationary boundary but will pose no threat of precipitation Sunday into Monday a dry air filters in at the mid-levels and subsidence increases as a result of the high. Sunday`s high temperatures will be the cooler of the two dry days with mid 70s to low 80s at higher elevations and mid to upper 80s in large valley areas. Monday will then feature highs in the upper 70s to low 80s above 1500 ft with more widespread mid/upper 80s to pockets of low 90s in the Hudson Valley courtesy of the slight increase in geopotential heights aloft and the surface anticyclone looking to be directly over the region. Luckily, with dewpoints anticipated in the upper 50s to mid 60s, heat indices Monday should not reach Heat Advisory criteria. Lows Sunday night will be in the mid 50s to low/mid 60s. The aforementioned surface high will begin its southeast exit from eastern New York and western New England beginning Monday night and heights aloft will begin to decrease in advance of a disturbance upstream. Conditions throughout the night will remain largely dry, however, with low temperatures Monday falling into the 60s. Attention then shifts to Tuesday and Wednesday as a frontal system and associated shortwave look to be the source of potentially widespread showers and some thunderstorms. Guidance is in fair agreement that a surface low will track from the Great Lakes north and east into southeast Ontario/southwest Quebec as the aforementioned shortwave rotates through the Great Lakes and Ohio Valley Tuesday. A secondary surface low also looks to potentially develop within the Mid-Atlantic region, providing an extra source of convergence near the area of PVA within the shortwave to enhance lift ahead of the system`s cold front. Showers look to begin Tuesday evening to the north and west of Albany, overspreading to the south and east throughout the night and into Wednesday. Long range guidance indicated some weak to moderate instability across portions of the region that could aid in some embedded rumbles of thunder Tuesday evening into Wednesday, but confidence is not yet high in the likelihood of severe convection potential. We will continue to monitor this potential as lead time decreases. High temperatures Tuesday will be similar to those of Monday especially if showers hold off until the evening/overnight hours as current guidance suggests. Again, heat indices look to fall below Heat Advisory criteria. Low temperatures Tuesday night will be primarily in the 60s. Wednesday will then be a cooler day with 70s anticipated above 1000 ft and low to mid 80s in valley areas. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... Through 18Z Friday...A frontal boundary draped across much of Upstate NY evident as a region of enhanced cloud cover on regional satellite imagery will continue to serve as a focus for rain shower and possibly thunderstorm development through the afternoon, with showers most likely at POU and possibly affecting PSF. Farther north at ALB/GFL, there remains a slight chance for brief, isolated showers, but confidence in impacts is far too low for TAF inclusion. Otherwise, diurnal cu at 3-5 kft will persist through the afternoon north of the boundary, while VFR cigs are expected to the south nearer to the front. While cloud cover may remain elevated overnight tonight, ample low level moisture may still result in patchy fog/mist after 08-10Z Fri, most likely in favored valleys and where rain showers occurred through the afternoon. Given uncertainties in exact locations, have included MVFR vsbys with mist at GFL/POU/PSF, but maintained VFR conditions at ALB. Any vsby restrictions will end quickly after sunrise as the July sun angle quickly burns off any fog/mist, though a low stratus may persist due to the abundant moisture beneath the nocturnal inversion. Otherwise, VFR conditions will prevail again after 12Z Fri, with clouds increasing from the south as the boundary lifts back northward as a warm front. Southeast to southwest winds at 5-10 kt will continue through this evening, before diminishing to calm or light and variable overnight after 00-03Z Fri. Light winds increase generally out of the south after 12Z Fri at 5 kt or less. Outlook... Friday Night: High Operational Impact. Likely SHRA...TSRA. Saturday: Moderate Operational Impact. Likely SHRA...TSRA. Saturday Night: Low Operational Impact. Slight Chance of SHRA...TSRA. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: Moderate Operational Impact. Chance of SHRA...TSRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Frugis NEAR TERM...Frugis/NAS SHORT TERM...Frugis LONG TERM...Gant AVIATION...Picard