Area Forecast Discussion
Issued by NWS Albany, NY
Issued by NWS Albany, NY
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712 FXUS61 KALY 192349 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 749 PM EDT Fri Jul 19 2024 .SYNOPSIS... High pressure will be positioned over the region tonight, providing continued dry and relatively cool conditions. Temperatures will warm to slightly above normal levels Saturday through Monday, with low probability of a shower or thunderstorm in some spots each day. There will be better chance for more widespread showers and thunderstorms Tuesday through Thursday, with more humid conditions as well. && .NEAR TERM /THROUGH SATURDAY/... .Update....A very pleasant July evening continues tonight with temperatures in the 70s to low 80s with dew points in the 50s leading to comfortable humidity levels. Diurnal driven cumulus clouds will fade as we lose daytime leaving us with mainly clear skies as high pressure builds into the Northeast. Nearly ideal radiational cooling will ensue tonight resulting in morning low temperatures cooling into the 50s to low 60s. We say "nearly" ideal since some cirrus clouds associated with a disturbance brewing off the mid-Atlantic coast will expand northward before sunrise. Cirrus clouds likely reach just north of I-90 into southern VT based on 300hPa RH guidance with the southern/western Adirondacks remaining mainly clear. Coolest temperatures will likely be found here with lows in the low 50s (pockets of upper 40s in the highest terrain). Some patchy fog cannot be ruled out in the Upper Hudson Valley as lows approach their respective dew points. Previous discussion...High pressure will be positioned directly over the region tonight, bringing mainly clear skies and light winds. Some high level clouds will start to increase from the south/west late. With a continued dry air mass in place, lows will be slightly below normal again, ranging from upper 40s the W. Adirondacks to upper 50s in the Hudson Valley. Patchy fog may occur in favored sheltered areas and near bodies of water. Sat looks to be mainly dry with high pressure still in place, but gradually weakening. Guidance continues to show a weak disturbance brushing the southern part of the area during the afternoon, which may produce isolated showers/T-storms. Will maintain 20% PoPs for areas south of Albany considering limited moisture, weak instability (SBCAPE ~500 J/Kg) and modest forcing. The air mass does warm compared to Fri, so highs are expected to range from the upper 70s in the higher terrain to mid 80s in lower elevations. Humidity levels remain modest, with dewpoints in the 50s to lower 60s much of the day. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... Sat night, a large upper level low will be tracking eastward across Quebec. While the southern edge of the upper low should remain north of our area, a associated weak surface cold front south of the upper low is expected to move into the Adirondacks. There still looks to be limited moisture available, so will mention just isolated showers there with dry conditions elsewhere. Lows will be milder than the past few nights, but still near normal ranging from mid/upper 50s in the mountains to lower/mid 60s in the valleys. As the upper level flow becomes confluent on Sun, the aforementioned weak cold front will basically become diffuse over our area. So not much activity is expected, with just an isolated shower/T-storm in some spots mainly from around Albany north. Most of the area and time will be dry though. Highs may be a few degrees warmer than Sat given expected sunshine, with highs in the mid to upper 80s in lower elevations. Humidity still looks to be relatively comfortable, with dewpoints mainly in the upper 50s to lower 60s. Any isolated convection should wane Sun evening due to diurnal effects and lack of forcing. Weak high pressure builds back in Sun night, providing tranquil conditions and additional drying. Low temperatures will range from the upper 40s in the W. Adirondacks to mid 60s in the mid Hudson Valley. On Mon, the flow aloft becomes more SW, so moisture will start to slowly increase. Dewpoints in lower elevations should rise into the mid 60s, making it feel slightly more humid. Dry conditions should generally prevail, with just low (20%) probability of a diurnally driven shower/T-storm in some spots. High temperatures look similar to Sun, with upper 70s/lower 80s in the mountains and mid/upper 80s in the valleys. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The pattern becomes more active for much of the long term period. Starting Tue, a west-east oriented front is forecast to set up somewhere over our area or in close proximity. This front looks to be quasi-stationary through at least Thu, until an upstream upper level trough kicks it out. So this pattern will likely result in multiple rounds of showers and thunderstorms each day. The most likely times for greater coverage should be during the diurnally favored afternoon/evening hours. Will mention higher PoPs (60-70%) during these more favored times, and 30-50% PoPs at other times. With PWAT anomalies forecast to increase to +1 to +2 STDEV, and remain above normal, locally heavy rainfall may occur in some areas. Will have to watch for any locations that receive repeated rounds of heavy rain, with a potential for isolated flash flooding. Will continue to monitor trends until details come into better focus. Temperatures looks to be near normal for highs and above normal for lows, with clouds/showers around and humid conditions. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Through 00 UTC/Sunday, mainly expecting VFR conditions for all TAF terminals. Diurnally driven cumulus clouds dissipate after sunset this evening followed by cirrus that expand northward out of the mid-Atlantic for the pre-dawn hours. Cirrus clouds linger into the daytime but remain mainly from around I-90 into the southern VT southward. Some patchy fog may develop near GFL which remains mainly clear tonight and including potential for MVFR visibilities starting around 08 UTC. Any fog should diminished by 12 UTC. VFR conditions continue through the day for the terminals with potential for some isolated showers or storms to develop around POU after 18 UTC. Only included VCSH for now as there remains uncertainty on where and when exactly showers may develop or impact. Light and variable winds through sunrise with southwesterly winds developing by 15 - 18 UTC becoming sustained 5-8kts with gusts up to 15kts. Outlook... Saturday Night: No Operational Impact. NO SIG WX. Sunday: Low Operational Impact. Slight Chance of SHRA...TSRA. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: Low Operational Impact. Slight Chance of SHRA...TSRA. Tuesday: High Operational Impact. Likely SHRA...TSRA. Tuesday Night: Moderate Operational Impact. Likely SHRA...TSRA. Wednesday: High Operational Impact. Likely SHRA...TSRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...JPV NEAR TERM...JPV/Speciale SHORT TERM...JPV LONG TERM...JPV AVIATION...Speciale