


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
046 FXUS61 KALY 201042 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 642 AM EDT Wed Aug 20 2025 .SYNOPSIS... A low pressure system and upper level disturbance bring beneficial rain to the region through today before the end of the week and into the first half of the weekend sees the return of dry weather. Additional chances for showers and some thunderstorms come Sunday into the beginning of next week as an unsettled pattern takes hold of the region. Temperatures remain cool by late August standards for much of the next seven days, though values will warm closer to normal for Friday and Saturday. && .DISCUSSION... A positively-tilted, mid-level shortwave, whose axis extends south and west from southeast Ontario through the eastern Great Lakes into the Ohio Valley, encroaches from the west almost directly atop a surface cyclone also spanning the eastern Great Lakes and Ohio Valley regions. Increased low-level convergence resulting from the inverted trough nosing into the region about the low intersects the divergent region of the upper trough, allowing an initial batch of rain to move through the region early this morning. Additional rounds of rain will accompany the deepening of the trough aloft and the southeastward slide of the surface low today as low to mid-level frontogenetical forcing increases courtesy of the steepening temperature gradient forced by winds backing from the southeast to the east (and eventually northeast). Latest CAMs still seem to be struggling a bit with a consensus as to the spatial extent of rain throughout the day, likely due to their differences in the resolution of low- level dry air and mesoscale drying affects from downslope winds. Additionally, the track of the surface low has shifted slightly farther south with an adjacent anticyclone remaining just off to our north and east. Therefore, the heaviest QPF has been lowered slightly, compressed, and shunted just a bit farther south than previous forecasts. Still, enhanced FGEN, upslope flow, and enhanced low level convergence will lead to an axis of more moderate rainfall mainly in the southwestern Mohawk Valley, northeast Catskills, and Helderbergs. Storm total amounts are progged to reach near 0.5" to 1.5" with locally higher amounts in the aforementioned areas of 1.65" and locally lower amounts in portions of the Southwest Adirondacks, lower Mid-Hudson Valley/northwest Connecticut, and Upper-Hudson Valley of ~0.25" to 0.4". Highs today will be much cooler than typical late-August standards with mid/upper 50s to low/mid 60s anticipated. Rain begins to dwindle this evening, becoming mere light, scattered showers by tonight before ceasing early Thursday morning. Lows tonight will fall to the upper 40s to mid/upper 50s. The aforementioned shortwave trough will continue its southeastward departure through the day Thursday, intersecting Hurricane Erin just in time to help kick it out to sea and away from the New England Coast. Locally, surface high pressure will begin to encroach from the northwest with amplifying heights aloft reinforcing dry conditions. Temperatures will consequently begin to warm, rising into the mid/upper 60s to low/mid 70s Thursday and into the mid/upper 70s to low/mid 80s by Saturday as the ridge aloft crests over the Northeast. Low temperatures Friday night will be largely in the 50s with mid 50s to low 60s expected on Saturday night. Tranquility comes to an end Sunday into the beginning of next week as an unsettled pattern sets in. Saturday`s ridge will be forced to the east as a large-scale trough digs south into the Midwest about the southern periphery of a closed low situated in central Ontario. Ahead of the attendant cold front, showers and potential thunderstorms look to spread into the region whilst a fairly potent shortwave and associated vort max rotate about the mean flow of the trough, potentially forcing its slight negative tilt by Monday afternoon/evening. Additional rounds of showers and possible thunderstorms would linger into Tuesday as additional shortwaves pulse through the primary upper trough, but exact coverage and severity of any showers and thunderstorms Sunday through Tuesday is uncertain at this time. Timing will play a big role in determining these elements of the forecast. So, for now we have maintained the NBM PoPs which keep most of the precipitation confined to Sunday and Monday. Temperatures during this time will once again fall cooler than late-August standards with upper 60s to low 80s Sunday falling to 60s to low/mid 70s by Tuesday. Lows Sunday night will remain on the milder side with values in the mid 50s to low 60s, but Monday night and Tuesday night will see values in the 40s and 50s. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... Overall thinking for the aviation forecast remains on track with MVFR/IFR conditions prevailing throughout the day with widespread SHRA. Confidence has increased in periods of IFR visibility restrictions at KALB and KPSF where TEMPO groups were added with this forecast cycle. More widespread IFR ceilings are forecast to develop across the region after 03Z this evening. Southeast to east winds during the morning hours are forecast to shift to northeast late this afternoon into this evening. Outlook... Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: Low Operational Impact. Slight Chance of SHRA. Sunday: Moderate Operational Impact. Likely SHRA...TSRA. Sunday Night: High Operational Impact. Likely SHRA...TSRA. Monday: Moderate Operational Impact. Likely SHRA...TSRA. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Gant DISCUSSION...Gant AVIATION...TH