


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
238 FXUS61 KALY 070805 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 405 AM EDT Mon Jul 7 2025 .SYNOPSIS... Very humid and hot today with chances for showers and thunderstorms capable of producing heavy downpours and gusty winds mainly in the western Mohawk Valley and western and southern Adirondacks as a cold front slowly sinks out of Canada. Additional showers are possible south of I-90 as the remnants of tropical cyclone Chantal track into the mid- Atlantic. Muggy and very warm again tomorrow with additional showers and thunderstorms capable of producing heavy downpours mainly south of I-90 as our cold front continues slowly tracking southward. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Key Message: - Dangerous heat expected from the Capital District into the Mohawk Valley and Upper Hudson Valley today due to the combination of high temperatures in the upper 80s to low 90s and very humid conditions. - Areas of heavy rain and embedded thunderstorms likely in the Southwest Adirondacks and Mohawk Valley later this afternoon into this evening. Localized flooding possible where heavy rain can repeatedly impact a given area and locally damaging winds possible should storms become strong to severe. - Locally heavy rain possible in the mid-Hudson Valley, eastern Catskills into parts of western New England as the remnants of Chantal track into the mid-Atlantic today. Discussion: We start the day under mainly sunny skies as broad ridging persists over the Northeast while a cold front positioned well to out north in southern Canada slowly tracks southward. Latest water vapor and IR imagery also shows the remnants of tropical cyclone Chantal rapidly weakening as it tracks northward into VA and the mid-Atlantic. Southwest flow aloft will advect cirrus clouds from Chantal northeastward into the our region this morning and especially this afternoon so expect sun to fade behind thickening cirrus. Otherwise, it will be uncomfortably humid today as PWATs rise to 1.5 - 2.25 inches and dew points reach into the upper 60s to low 70s. The combination of high humidity, sufficient insolation and weak capping will easily allow instability to develop across the region through the day with ML CAPE values rising to 1.5k to 2k J/kg by this afternoon. In addition, 850hPa isotherms again ranging +17C to +18C will result in daytime highs rising into the upper 80s to low 90s. When combined with the high humidity, expect dangerous heat index values or "feel-like" temperatures reaching into the mid to upper 90s. Highest confidence for heat index values to reach or slightly exceed the 95F criteria is in the Capital District, Mohawk Valley, and Upper Hudson Valley where we issued the heat advisory. Sensitive populations should limit strenuous outdoor activities and drink plenty of water, even if not thirsty, to stay hydrated. Areas further south in the mid-Hudson Valley were close to the criteria but given increased cloud coverage and shower potential from the remnants of Chantal, held off on heat advisories there. There will be two main regions to monitor for potential heavy rain/localized flooding and thunderstorm development. The first area will across the western and southern Adirondacks into the western Mohawk Valley later this afternoon (18 - 21 UTC) into early evening. Our cold front sinking out of southern Canada will be very slow moving and therefore will give ample time for this region to destabilize in response to the high humidity and insolation. In fact, there is good consensus that such conditions should generate SB CAPE values exceeding 2k J/kg. By the time the front approaches by mid to late P.M and erodes any minimal cap, high res guidance shows thunderstorms/areas of heavy rain quickly becoming focused along the boundary given weak deep layer shear values around 20-25kt oriented parallel to the front. With high FZ heights/warm cloud depths 13-14kft and high PWATs ~2", heavy downpours can easily occur and could train/repeatedly impact over an area as cloud layer winds remain parallel to 850hPa winds. The HREF shows a broad region of 30-50% probabilities for 3-hrly QPF amounts to exceed 1 inch between 18 - 00 UTC oriented along the front and these probabilities extend into parts of the western Mohawk Valley. WPC expanded its slight risk (level 2 of 4) in its Day 1 ERO across the Southern Tier into parts of Oneida County but stops right at the Herkimer County border where the marginal risk (level 1 of 4) continues. This makes sense as 3-hrly flash flood guidance is quite high at 2.25 - 3 inches so any flooding impacts should be limited to the typical trouble spots/poor drainage and urban areas. Regardless, we will maintain a close eye on potential localized flooding late this afternoon into this evening. A few storms could grow upscale enough to result in localized damaging winds mainly from wet microbursts given DCAPE values >500 J/kg but with forecast soundings showing mid- level lapse rates limited to 5.5 - 6C/km, any strong to severe storms should be isolated. SPC expanded its marginal risk (level 1 of 5) in its Day 1 Convective Outlook to cover more of the southwest Adirondacks and Mohawk Valley but given the late arrival of the front, severe storms should be isolated. The second area to monitor for heavy downpour potential will be south of I-90 mainly in the eastern Catskills, mid-Hudson Valley and NW CT/southern Berkshire where moisture streaming ahead of the remnants of Chantal may result in disorganized areas of rain and embedded isolated thunderstorms. While the remnant circulation of Chantal will continue to quickly become sheared out and remain well to our south crossing into the DelMarVa, southwest flow aloft will direct leftover weak troughing towards southern New England. Sufficient weak forcing ahead of the trough combined with mid- level moisture within a region of very high PWATs (ranking among the highest values in the 30 yr CFSR model climo) looks to result in a few areas of rain and thunderstorms with heavy downpours certainly possible given high warm cloud depths ~13-14kft that can easily support efficient warm rain processes. While there is rather good consensus on showers reaching our southern zones, there is discrepancy on the resultant QPF. The HREF probabilistic guidance shows nearly 50% chance that 3-hrly QPF exceeds 1 inch this afternoon while QPF spread from the NBM during this window is limited to between 0 and 0.25". The potential for heavy rain is certainly there given the moisture rich environment but weak forcing may limit the coverage. WPC maintained a broad brushed marginal risk in its Day 1 ERO that includes these southern zones. We maintained the heavy rain potential wording in the forecast for this afternoon into the early evening and given very weak flow through the column <20kts, localized flooding may occur from slow moving storms or where storms repeatedly impact. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... Key Message: - Locally heavy downpours and isolated severe thunderstorms potential continues into Tuesday mainly focused south of I-90 as a slow moving cold front pushes south/east through the region. Discussion: Oppressive humidity continues into tonight as our cold front continues its slow progression south and eastward across the forecast area. Additional areas of rain and locally heavy downpours with isolated thunderstorms likely continue into the overnight hours along the front with storms diminishing after Midnight. By Tuesday morning, the front should be positioned across the Capital District and continuing to push south/east. The air mass ahead of the front mainly south of I-90 will remain very warm and very humid as PWATs remain high around 2". While the 850hPa isotherms will still be elevated at +17C to +18C, increased cloud coverage and shower activity should limit daytime heating and therefore we are not as confident in temperatures becoming warm enough to warrant additional heat advisories. It will be close though as our latest forecast shows highs reaching into the upper 80s to around 90 with dew points in the upper 60s to low 70s resulting in heat index values or "feel-like" temperatures in the mid to upper 90s in far southern Ulster/Dutchess/Litchfield. Such a warm and humid air mass combined with daytime heating will also result in SB CAPE values ranging 1000 - 2000 J/kg across the mid-Hudson Valley, NW CT, southern Berkshire and eastern Catskills and with deep layer shear values 20-30kts and slightly steeper mid-level lapse rates around 6C/km, we will once again need to monitor severe weather and heavy downpour potential as the front pushes southward through the day resulting in areas of showers and thunderstorms. The SPC Day 2 Convective Outlook maintains its marginal risk (level 1 of 5) across these southern zones with damaging winds the primary hazard from any severe storm and WPC continues it marginal risk focused across far southern zones in its Day 2 ERO. Again, high PWATs/high warm cloud depths and cloud layer mean winds oriented parallel to the boundary will support heavy rain focused along the front which could result in localized flooding. Areas behind the front from the Capital District north/west will experience lowering humidity through the day as northwest winds advect a drier air mass into the area but temperatures will still be very warm reaching into the mid to upper 80s with upper 70s in the southern/western Adirondacks. POPs trend lower Tuesday night as the front finally pushes to our south with drier air arriving in its wake leading to partial clearing skies and more comfortable temperatures/humidity. We finally get a break from the wet weather by Wednesday as the front settles to our south and high pressure briefly builds over the Northeast. However, it will still be quite warm albeit not as humid as weak southwest flow continues aloft supporting high temperatures rising into the mid to upper 80s with upper 70s in the higher terrain. Troughing becomes re-established across southern Canada by Wed night with the main trough axis remaining well to our north/west. We maintained slight chance POPs with chance POPs across far southern zones as the front remains stalled to our south and weak height falls ahead of the trough may result in additional shower development along the boundary. Some members of guidance even suggest a weak sfc low develops along the boundary resulting in more organized areas of rain but not enough confidence to include anything more than chance POPs in southern zones at this time. Otherwise, Wed night remains warm and a bit muggy with overnight lows and dew points in the 60s. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Coming soon. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... Through 06z Tuesday...VFR conditions will prevail through much of the night with just a few mid and high clouds around. Scattered low ceilings in the MVFR range will be possible at KPSF/KPOU early this morning, along with patchy fog at KGFL. However, confidence for both these impacts are low due to guidance backing off on low stratus development, and stronger surface winds limiting fog coverage. Going into the daytime Monday, expect continuation of VFR conditions with the exception of KPOU/KPSF/KALB where PROB30 groups have been maintained for a low potential for afternoon showers and storms. COnfidence for showers/storms at KGFL is low at this time as majority of guidance weakens the storms before entering the vicinity, but this may be adjusted in later TAFs. Late in the period, MVFR ceilings will be possible at all terminals with the approach of a frontal boundary from the northwest, but impacts should hold until after 08/06z. Winds will be around 5 kt from the S/SE tonight, increasing to 5-10 kt tomorrow with gusts up to 15-20 kt during the afternoon. Outlook... Tuesday Night: Low Operational Impact. Slight Chance of SHRA. Wednesday: Low Operational Impact. Slight Chance of SHRA...TSRA. Wednesday Night: Low Operational Impact. Slight Chance of SHRA. Thursday: Moderate Operational Impact. Likely SHRA...TSRA. Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Friday: Moderate Operational Impact. Chance of SHRA...TSRA. Friday Night: Low Operational Impact. NO SIG WX. Saturday: Low Operational Impact. Slight Chance of SHRA...TSRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...Air Quality Alert from 11 AM this morning to 11 PM EDT this evening for CTZ001-013. NY...Heat Advisory from noon today to 8 PM EDT this evening for NYZ038-040-041-043-049-050-052-053-083-084. MA...None. VT...None. && $$ SYNOPSIS...Speciale NEAR TERM...Speciale SHORT TERM...Speciale LONG TERM...Speciale AVIATION...Speck