Area Forecast Discussion
Issued by NWS Albany, NY
Issued by NWS Albany, NY
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
435 FXUS61 KALY 080548 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 148 AM EDT Wed May 8 2024 .SYNOPSIS... A warm front will increase clouds with showers and some thunderstorms today. A couple storms this afternoon could be on the stronger side. After a seasonable day on Thursday with showers increasing in the afternoon, temperatures trend cooler for the end of the week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 1257 AM EDT...Mid and high clouds are beginning to increase over w-central NY spilling into eastern NY. Some showers and a few thunderstorms are getting into western NY ahead of the warm front near the NY-PA border. Temps have cooled a little quicker into the low-mid 40s in the southern Dacks and eastern Catskills due to radiative cooling with the sfc high nearby. For example, Indian Lake fell to 43F in the NYS Mesonet. We retrended hourly temps and tweaked the timing of the showers and elevated thunderstorms which will increase 4-6 am. The best EML is upstream at the Davenport, IA 00Z sounding. Our 00Z sounding is very dry with a PWAT of 0.34". Upstream over extreme western NY, the SPC RAP Mesoanalysis indicates PWATs jump quickly to an inch beneath the weak elevated instability with Showalter Stability indices of -2C. We kept isolated to scattered thunderstorms in the forecast in the mid to late morning. Lows due to wet bulb cooling will be in the 40s to lower 50s. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... Forecast for tomorrow remains complicated, with a chance for some stronger storms...The day begins with the surface warm front continuing to lift northwards through our region. There will likely be lingering convection around to start the day associated with this warm front, especially north of I-90. Then, later in the afternoon, the upper low will open up as it tracks through upstate NY. The system`s cold front will track through tomorrow evening, pre-frontal trough will track through the region tomorrow afternoon. Behind the warm front, we should get into the warm sector with temperatures climbing well into the 70s, especially for areas along and south of I-90. With steep mid-level lapse rates in excess of 7C/km, this will lead to SBCAPE values approaching 1000 J/kg, with some pockets of locally higher values possible in the Mid Hudson Valley and western New England. Deep-layer shear also increased to 60-70 kts. While this parameter space is fairly impressive for our area, the best upper forcing will remain to the north and will not overlap with the best instability/shear. The best chance for any stronger storms appears to be across the Mid Hudson Valley, western MA, and western CT with any storms that develop with/ahead of the pre- frontal trough. Therefore, it looks like a fairly narrow window from very late morning through mid-afternoon where storms are possible. With mean flow perpendicular to the low-level forcing, and weak upper forcing, some discrete storms could develop in these areas ahead of the pre-frontal trough. The severe threat is conditional on convection initiating, but if any storms do develop the primary threats look to be gusty winds with steepening low-level lapse rates and mid- level drying. Mid- level dry air and long, straight hodographs also indicate the possibility of hail with any discrete storms that develop. Accordingly, SPC has placed our area in a marginal risk for severe weather tomorrow. Behind the pre-frontal trough, winds shift to the west and drier low and mid-level air gets advected into the region, which will reduce instability and make convective initiation more difficult. A few additional showers/storms are possible later in the evening for the Mohawk Valley/western Adirondacks ahead of the true cold front, but the severe threat looks more limited at this time with waning instability due to drier air and loss of daytime heating. Tomorrow night, lingering showers/thunderstorms come to and end in the evening/early in the overnight period as heights rise aloft. The cold front drops southwards across the region, but may not make it all the way to our southern border with OKX. For areas behind the front, northwesterly winds advect cooler and drier air into the region. Lows will generally be in the 40s (north) to 50s (south). Some patchy fog can`t be ruled out either, especially ahead of the cold front. Thursday through Friday...Thursday starts off dry but rain chances increase through the day. A broad, positively tilted upper trough will approach the Great Lakes, and there will be numerous upper shortwaves rotating around this upper trough. At the surface, an area of low pressure will track from the Ohio Valley off the Mid-Atlantic coast, bringing increased chances for showers to the region tomorrow afternoon through Friday. Due to the amount of small-scale shortwaves, there is quite a bit of forecast uncertainty, more than would be expected at this lead time. The best chance for showers will be for areas along and south of I-90, although some sources of guidance suggest showers could make it much further north. Chances for showers continue through Thursday night and into Friday, with a secondary surface low potentially tracking towards our region Friday. Will attempt to refine the timing and amount of precipitation over the coming days with guidance hopefully coming into better agreement. Daytime highs Thursday and Friday will be much cooler than the previous few days, with overnight lows in the 40s to around 50 Thursday night. Severe weather is not expected during the Thursday through Friday timeframe. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Unsettled and cool conditions describes the weather pattern for the upcoming weekend as a long wave trough remains positioned over the Eastern CONUS with a series of shortwaves tracking from the Midwest into the Northeast. After showers Friday night, some brief ridging and subsidence aloft ensues for at least the first half of Saturday which should support a dry break. However, an additional shortwave from the Ohio Valley will provide enough lift to support showers returning Saturday afternoon into Saturday night. The shortwave lingers overhead through Sunday with sufficient mid-level moisture and some weak warm air advection as winds aloft shift to the south or southeast. This set-up will maintain chance POPs through the day with even a slight chance for thunderstorms as some instability may sneak northward. While temperatures Saturday remain cooler than normal with highs only in the 50s to low 60s thanks to west-northwest flow aloft, temperatures should trend a bit milder for Sunday rising into the low to mid 60s in the valley with mid to upper 50s in the higher terrain and hill towns. There remains some uncertainty on how the pattern evolves for Monday into Tuesday as weak shortwaves continue to track aloft while weak high pressure builds at the surface. Therefore, we maintained low end chance POPs for Monday into Tuesday but this may change as guidance becomes into better agreement. Despite the uncertainty in the evolution of shortwaves aloft, there is better agreement for temperatures to trend milder and more seasonable as a milder air mass from the Ohio Valley spills eastward. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... A warm front will approach from the west Wednesday morning, followed by a cold front passing through from the northwest in the late afternoon. VFR conditions are expected through at least 08Z/Wed. Showers and a few thunderstorms currently developing across western New York will reach the TAF sites between 09Z-12Z/Wed, and may linger until 14Z-16Z/Wed. A period of low MVFR Cigs and brief MVFR/IFR Vsbys will be possible within heavier downpours. Showers/thunderstorms should become isolated/scattered between 15Z-19Z/Wed, then taper off. VFR conditions are then expected later this afternoon through early evening. Light/variable winds will become south to southwest at 5-10 KT by mid morning, then will shift into the west after 19Z/Wed and increase to 10-15 KT with some gusts up to 25 KT, strongest at KALB and KPSF. Winds will become west to northwest and decrease to 8-12 KT toward and after 00Z/Thu. Winds will be stronger, and variable in direction in and near any thunderstorms. Outlook... Wednesday Night: Low Operational Impact. Slight Chance of SHRA...TSRA. Thursday: Moderate Operational Impact. Likely SHRA. Thursday Night: High Operational Impact. Likely SHRA. Friday: High Operational Impact. Likely SHRA. Friday Night: Moderate Operational Impact. Chance of SHRA. Saturday: Moderate Operational Impact. Chance of SHRA. Saturday Night: Low Operational Impact. Slight Chance of SHRA. Sunday: Moderate Operational Impact. Likely SHRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Main/Wasula NEAR TERM...Wasula SHORT TERM...Main LONG TERM...Speciale AVIATION...KL