Area Forecast Discussion
Issued by NWS Albany, NY
Issued by NWS Albany, NY
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458 FXUS61 KALY 121419 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 1019 AM EDT Wed Jun 12 2024 .SYNOPSIS... Mainly dry weather is expected today as an upper-level low slowly departs the region, but skies will remain partly to mostly cloudy. Dry weather can be expected through Thursday before the chance for showers and thunderstorms increases Thursday night through Friday courtesy of an approaching cold front. A dry, seasonable weekend then gives way to a possible stretch of unseasonable warmth for the beginning into the middle of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... .UPDATE...As of 1015 AM EDT, latest water vapor imagery shows an upper level low along the New England coast and continues to depart farther to the east. Meanwhile, an upper-level shortwave is approaching from the Great Lakes and will cross the region into this evening. Ahead of this shortwave, a fairly expansive area of low to mid-level stratus is advancing eastward from the Adirondacks and Mohawk Valley. Ahead of this, some diurnal cumulus clouds are already developing as convective temperatures are already being reached. Trends suggest these clouds may hold strong for a good portion of the day, so cloud cover was increased much of the day to indicate a mostly cloudy sky. Conditions throughout the day today should remain primarily dry, though a stray upslope shower or two is possible in the Southern Greens and Southern Adirondacks as we are still under the influence of the departing upper low and approaching shortwave. The extra clouds have caused temperatures to be slow to rise, especially in western areas. As a result, we slowed the temperature rise and highs were also lowered a bit as well. From the Hudson and points east, highs were generally held at this time, but may need to be tweaked pending the eastward progression of the stratus deck. Regardless, highs will reach the 60s and 70s. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... Atmospheric heights gradually rise this evening into tonight as the aforementioned upper-low continues to pull away from the region and weak ridging builds in aloft. Dry conditions will, therefore, be sustained through the overnight period tonight with skies becoming mainly clear. A favored environment for radiational cooling, low temperatures tonight will fall into the upper 40s to low 50s with pockets of mid 50s in the Mid- Hudson Valley and mid 40s above 1500 ft. Dry conditions persist into Thursday as high pressure dominates at the surface and heights aloft remain relatively stagnant. Flow aloft gradually backing to the southwest will aid in ushering in a warmer airmass than previous days with 850 mb temps increasing to +14 to +16 C. This, paired with mainly clear skies through peak heating hours, will support highs in the upper 70s to mid and possibly upper 80s in valley areas. However, clouds will be on the increase once again beginning Thursday afternoon as an upper-level trough approaches from the west. By Thursday afternoon, a broad surface low will become situated just south of the Hudson Bay with the axis of a broad mid/upper- level trough extending through the Great Lakes. As the surface low deepens and tracks north and east further into central Quebec, the aforementioned trough will dig south and east further into the Great Lakes and Ohio Valley regions, gradually taking on a positive tilt. Mid/upper-level winds will begin to increase across eastern New York and western New England as a result of a developing jet max embedded within the leading edge of the trough. At the surface, a northeast to southwest-extending cold front will remain upstream through Thursday night, though shower chances will increase out ahead of it as large scale ascent becomes favorable with increasing PVA and warm air/moisture advection increases through continuous southwesterly flow. Though there continues to be some level of uncertainty in the timing of the cold fropa due to model disagreement, general consensus would point towards a slow northwest to southeast progression throughout the day Friday. Despite Thursday night`s increased cloud coverage lingering into Friday, medium-range models and ensemble members indicate areas of moderate instability (500-1000 J/kg according to the latest GEFS) Friday afternoon specifically within the Capital Region, Mid- Hudson Valley and portions of western New England (~45-60% SBCAPE > 1000 J/kg per the latest SREF) courtesy of possible breaks of sun in these areas during the morning and possibly early afternoon. With a persistent southwesterly flow regime, moisture will continue to be on the increase throughout the night Thursday into Friday with dew points anticipated to increase to the upper 50s to 60s and PWATs to rise to about 1.5" by Friday afternoon. Therefore, have included widespread chances for showers and thunderstorms throughout much of eastern New York and western New England for Friday. At this time, it is difficult to determine the anticipated strength of convection for Friday, but it is worth noting that the SPC has placed portions of the Mid-Hudson Valley and western New England in a Slight Risk for severe thunderstorms. Latest thermal profiles paint the picture of a low shear, moderate CAPE environment which could be a limiting factor in convection reaching severe strength. Additionally, the synoptic forcing, at this time, looks to be somewhat unfavorable with much of the area remaining largely within the right exit region of the upper-level jet. Increased vertical ascent forced through cyclonic vorticity advection within the upper- trough could help to compensate for this, but too many factors still remain uncertain to make that conclusion. However, all that said, there are some signals for periods of moderate to potentially heavy rain especially where instability is greatest given the increased moisture and anticipated forcing. Therefore, mentioned heavy rain with thunderstorms from Albany south and east Friday afternoon into Friday evening to account for this possibility. High temperatures Friday look to range from the mid/upper 70s to low 80s with pockets of low 70s at higher elevations. Showers and thunderstorms look to gradually taper off after sunset Friday night given the loss of daytime heating. Dry conditions will then be reinstated across the region with low temperatures anticipated to be in the mid/upper 40s to upper 50s. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Upper ridging steadily builds into the region from the west and amplifies as it builds into our region. A weak upper impulse is expected to track along or just north of the U.S./Canada border some time between Sunday night and Monday night. There are disagreements with the timing of this upper impulse, that would potentially bring an isolated shower or thunderstorm as a weakening wind shift boundary drops south. Once that upper impulse exits, upper ridging will amplify and potentially dangerous levels of heat may set up in our area. There is an increasing consensus from sources of guidance/ensembles for the potential dangerous levels of heat, so trends will be watched closely. Any wind shift boundary will just become a thermal surface trough once the hot airmass settles over our region. The upper ridging should provide enough of a midlevel cap to prevent any thunderstorm activity outside of an isolated storm perhaps in areas of terrain. Highs Saturday in the 70s with near 80 mid Hudson Valley and 60s to near 70 higher terrain. Highs Sunday in the upper 70s to lower 80s with lower to mid 70s higher terrain. Highs Monday in the 80s to near 90 and around 80 to lower 80s higher terrain. Highs Tuesday in the lower to mid 90s with mid to upper 80s higher terrain. The 90+ temperatures could continue beyond Tuesday. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... Upper disturbance producing a ceiling at around 5-6 kft across much of the region. A brief period of MVFR ceilings is expected between 12-14Z at KGFL and KALB. There are a few small breaks in the clouds but based on satellite imagery the holes in cloud coverage are trending more to filling in rather than expanding. Clouds are expected to break up this afternoon and evening. VFR ceilings and visibilities through today and tonight. Variable winds at less than 5 kt to near calm through mid-morning. Then south to west winds at less than 10 kt late this morning through afternoon, trending to calm this evening and tonight. Outlook... Thursday Night: Low Operational Impact. Slight Chance of SHRA. Friday: Moderate Operational Impact. Likely SHRA...TSRA. Friday Night: Low Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Gant/Rathbun NEAR TERM...Gant/Rathbun SHORT TERM...Gant LONG TERM...NAS AVIATION...NAS