Area Forecast Discussion
Issued by NWS Albany, NY
Issued by NWS Albany, NY
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307 FXUS61 KALY 140550 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 150 AM EDT Fri Jun 14 2024 .SYNOPSIS... A swift-moving cold front will track through the region today, bringing showers and thunderstorms, some of which could be strong to severe south and east of the Capital District. High pressure behind the front will then ensure a beautiful, dry weekend before a significant warm up is expected next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... .UPDATE...A band of showers has moved into Herkimer and Hamilton Counties this evening, bringing light to potentially moderate rainfall rates in these areas. Though some embedded rumbles of thunder were once associated with these convective showers, a general lack of instability has lead to the weakening of storms. Adjusted PoPs and sky cover to account for latest trends in shower activity. Also made minor adjustments to temperatures to reflect latest obs. Other than that, the forecast remains within good shape with this update. See the previous discussion below for additional details on the overnight forecast. .PREVIOUS DISCUSSION... As of 950 PM EDT... Flat upper ridging remains over our region, with surface high pressure located well to our east over the Atlantic. To the west, a frontal boundary is making its way across the Great Lakes and Ontario, with a surface low lifting northward across southern Canada. Ahead of this front, there is a prefrontal surface trough as well. MRMS imagery and lightning data shows a well developed line of showers and thunderstorms over eastern Ontario. Some scattered showers and embedded thunderstorms also extend eastward across southern Quebec. A few showers were even impacting the North Country and parts of the Adirondacks earlier, but these have mostly dissipated and/or lifted off to the northeast. CAMs suggest that line of showers and thunderstorms over Canada will be pushing eastward through the late evening hours and will be spreading towards the US border for tonight. However, the convection will be getting too far ahead of the surface boundary and will be weakening thanks to the loss of daytime heating. As a result, the majority of these showers and thunderstorms will fall apart as they get into our area. Still, a brief shower or isolated t-storm can`t be ruled out for the late night hours for northern areas. It`s even possible that a few showers potentially getting to the Capital District around sunrise, although this is rather uncertain and there may not be much left of this activity by then. Otherwise, skies will remain partly to mostly clear across our area through the overnight hours. Some passing high clouds ahead of the decaying convection looks to pass through, but limited other clouds are expected. There should be a persistent light southerly breeze through the night as well. It will be on the warmer side with lows mainly in the 60s, which will be milder compared to the past few nights. && .SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/... By tomorrow morning, the surface low will be located well to our north, with the trailing cold front approaching from the west. A second upper impulse will help drive this cold front southeastwards through our region tomorrow, which will result in showers and thunderstorms developing across the region. With a warm and relatively moist airmass ahead of the front, a few of these storms could be strong to severe with SPC having placed areas mainly south and east of Albany in a slight risk for severe storms. Highs will be mainly in the upper 70s north and west of the Capital District, with mid 80s possible in the Mid Hudson Valley and western CT. With the approaching cold front, upper shortwave, and the right entrance of the upper jet nearby, there will be decent forcing for ascent so showers should be fairly widespread tomorrow afternoon. Regarding the severe potential, the HREF mean suggests SBCAPE values of up to 1000-1500 J/kg overlapping with 30-40 kt of deep-layer shear. The shear profile is relatively top-heavy, but should still be sufficient for some organized convection. Any initially discrete cells should grow upscale into a line or line segments with the relatively strong forcing and unidirectional shear profile. With low-level dry air and relatively steep low-level lapse rates, damaging winds look to be the main threat with storms, but straight to slightly counterclockwise turning hodographs and strong storm-relative flow aloft also suggest the potential for a few storms to also contain large hail, especially before convection congeals into a line. The best chance for any severe storms looks to be from around noon through 00z, again focused south and east of the Capital District. One potential "failure mode" for severe weather is if morning showers/non-severe convection end up tracking further south and east than currently expected. If the morning showers make it south and east of the Capital District, then the risk for severe weather later in the day would be lower. Locally heavy rain is also possible with any storms, but with PWATs "only" around 1.5 inches, progressive storm motions, and dry antecedent conditions we are not expecting widespread hydro issues. Of course, the typical nuisance urban/poor drainage flooding is always possible should any of these heavier rainfall rates move over any urban areas. Showers and storms may linger into the evening tomorrow, but should come to an end between 00z and midnight. Things should dry out behind the cold front, with cooler and drier air being advected into the region. Lows will be in the upper 40s for the ADKs to mainly 50s elsewhere. Saturday and Sunday...We remain in a cool/dry advection regime behind the cold front, with surface high pressure building into the region with northwest flow aloft. It will be much cooler on Saturday with highs in the 60s for the terrain to 70s in the valleys. With the high directly overhead Saturday night, it will be quite cool with most areas dropping into the 40s and even a few upper 30s possible in the high terrain. Sunday remains dry but will be slightly warmer with highs mainly in the 70s. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Long term period begins Sunday night with surface high pressure sliding off the east coast of New England. A warm front will lift northeastwards across the region late in the overnight period, so lows will be a few to several degrees warmer than the previous night with lows in the 50s to around 60. Monday, we get into south/southwest return flow and warm advection around the periphery of the upper high. Upper ridging begins to build over the eastern half of the CONUS, so it will be quite a bit warmer than the previous couple days with highs in the mid 80s. This will be the start of a significant warming trend, as the upper ridge continues to amplify over the eastern US through the middle of next week. Ensemble guidance is in good agreement that most of our area will be within the 594 dam contour, with some deterministic guidance suggesting we may see 600 dam heights at 500 mb somewhere in the Mid Atlantic or Northeast. 850 mb temperatures climb into the low 20s Celsius, which will translate to surface temperatures in the 90s for many of our valley areas each day Tuesday through Thursday. With dew points well into the 60s each day, afternoon heat index values are may potentially reach or exceed 100 degrees for many valley areas Tuesday through Thursday. Heat advisories will likely be needed as we get closer to this event, with excessive heat warnings not completely out of the question. Overnight lows will be in the upper 60s to around 70, so even at night it will remain quite warm and muggy. Forecast confidence is relatively high that we will see hot/humid weather next week, although just how hot it gets remains somewhat uncertain. One potential factor that could lower temperatures slightly is an upper shortwave that will be tracking around the northern periphery of the ridge sometime Monday or Tuesday. All sources of guidance have this feature, although they differ on its track and timing. Where this feature tracks, there will be a few more clouds with isolated to scattered afternoon showers and thunderstorms, which could locally reduce temperatures. At this point, the greatest chance for a few showers or thunderstorms looks to be mainly north of I-90. Even if the "cooler" scenario were to play out, we would still likely see many areas reach or exceed heat advisory criteria Tuesday through Thursday. Confidence decreases for the middle and end of next week with most sources of guidance suggesting the ridge will break down at some point, but it is too soon to tell exactly when this will happen. The CPC is still expecting temperatures to average above normal for the 8-14 day timeframe. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... Line of weakening showers in northern NY is gradually dropping south and some of the showers will approach KGFL by 08Z and KALB by about 10Z. Predominant conditions will still be VFR because the showers should weaken considerably and become more scattered. A new line of showers and scattered thunderstorms is expected to develop after about 15Z near or just south and east of KALB. Other showers will for around KALB and including showers with MVFR conditions between about 15Z-19Z at KGFL and KALB. As the thunderstorms develop in the afternoon, including a brief period of thunder at KALB between 20Z-21Z, that will likely be shifted either earlier or later, depending on the actual observed storms later today. The best coverage and duration of showers and storms is expected at KPOU and KPSF, where thunderstorms are included between about 20Z- 23Z with MVFR conditions. Some brief bursts to IFR are possible in the heaviest rain but too brief to include in TAFs. By 22Z-24Z, rain exits KALB and KGFL, while some showers could linger at KPOU and KPSF until around 02Z-03Z. VFR conditions expected once the showers and storms exit this evening. Steady south winds through this morning at 10 Kt or less, with a gust around 15 Kt at times at KALB and KPSF. Thunderstorms could have gusts to 35 Kt this afternoon. Winds shift to west and northwest this afternoon at 10 Kt or less and continue this evening. Outlook... Friday Night: Low Operational Impact. Slight Chance of SHRA...TSRA. 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. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Gant NEAR TERM...Frugis/Gant SHORT TERM...Main LONG TERM...Main AVIATION...NAS