918 FXUS61 KBTV 042319 AFDBTVArea Forecast Discussion National Weather Service Burlington VT 719 PM EDT Sat Oct 4 2025
.SYNOPSIS... High pressure will remain the dominant weather feature through this weekend with temperatures climbing well above normal, with some daily record high temperatures in jeopardy tomorrow and Monday. Low relative humidity values and breezy to gusty winds are possible Monday ahead of our next cold front on Tuesday. Precipitation chances associated with the cold front look to increase Tuesday into Wednesday, with cool and dry conditions returning for the later half of the week.
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.NEAR TERM /THROUGH SUNDAY NIGHT/... As of 200 PM EDT Saturday...Dry and increasingly warmer air will continue to filter into the area as high pressure crests today overhead, and begins to shift east by tomorrow. Southerly flow will allow decent waa with 925mb temperatures today and tomorrow surging to 20-21C, leading to near record warmth for this time of year, nearly 10-15 degrees above normal at the surface. Highs today could reach near 80 across Vermont, and by tomorrow into the low to mid 80s everywhere outside of the higher terrain. Daily high records for tomorrow will likely be in jeopardy under this pattern, with the best chance to break daily high records tomorrow over the next 3 days. Southerly flow will keep temperatures mild tonight in the 50s which will be near record high lows for a few climate sites.
Dewpoints will be slightly higher than yesterday with southerly flow, however, with temperatures also higher, relative humidity values will still be in the 30-40% this afternoon and tomorrow afternoon. The lowest minimum RH today will be across southern Vermont in the Connecticut River Valley, and tomorrow across the St. Lawrence Valley. Increasing temperatures and continued low RH values will continue to exacerbate the ongoing drought.
As the ridge peaks today and begins to shift east tomorrow, there will still be some gradient flow, with winds generally southwesterly and on the breezy side near 10 mph. Channeled flow in the Champlain Valley will relax this afternoon for more calm winds tonight. Channeled flow will return tomorrow morning as it did today in the Champlain Valley with winds around the lake 10 to 15 mph.
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.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... As of 200 PM EDT Saturday...Monday will continue the warming trend from this weekend with 925mb temperatures still in the 20-21C range. Highs will be in the low to mid 80s outside of the higher terrain and upper 70s in the Adirondacks. It will be warm, though not as warm as Sunday. The ridge will shift eastward allowing increased south/southwesterly flow. Efficient vertical mixing Monday afternoon should help to dramatically dry out the vertical column of the atmosphere leading to a good dewpoint bomb scenario. Relative humidity values Monday will drop to near 30% areawide with some 25-30% not out of the question under potential dewpoint bombs. The best dewpoint bomb conditions will be across Vermont east of the Greens as downsloping off the Greens will aid mixing in addition to less cloud cover expected than over northern New York. Mixing Monday will also lead to gusty conditions. By Monday afternoon, a cold front will begin to approach the area with a low-level jet developing over the region. Gusts 20-25 mph are possible in the St. Lawrence Valley, with similar gusts possible in Vermont, particularly in areas that see efficient mixing and lower RH values. NBM guidance does not appear to handle this mixing nor winds ahead of the front well, thus some winds may be increased across the St. Lawrence in future forecast updates. These low, near-critical RH values, and increasing confidence in gusty winds, could lead to fire weather concerns Monday afternoon should these trends continue. The cold front begins to enter the area with increasing precipitation chances (20-30%) by late Monday night towards Tuesday morning.
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.LONG TERM /TUESDAY THROUGH SATURDAY/... As of 216 PM EDT Saturday...Focus of this period is on welcome rainfall Tuesday through Wednesday morning. Thereafter, dry and much cooler weather will return as another large area of Canadian high pressure will settle into the region. A mostly dry cold front may also bring a brief period of showers in the late Friday/Saturday timeframe, but predictability of this feature is low.
High probabilities (close to 100%) of rain continue for midweek with a strongly forced area of rain along and just behind a well-defined cold front. Forecast soundings are consistent with a slight chance of thunder in any convective elements. Warm, moist low level air, especially around the 850 millibar level, will support at least elevated instability and rumbles of thunder. GEFS Machine Learning 24-hour thunder probabilities in the 10-20% range seems reasonable on Tuesday. Given height falls coincident with the surface front and 30 to 40 knots of deep layer shear, if we had more heat and humidity to boost instability there may have been some severe weather potential. However, even 90th percentile surface based CAPE (a reasonable high end value) is in the 300 to 500 J/kg range. Instead, a good soaking rain remains the main impact of this event, with localized ponding of water in poor drainage areas. Through Tuesday evening, most of the rain will likely be over far northern Vermont and much of northern New York; thereafter, rain will shift south and east with several hours of rain leading to amounts averaging 0.5" to 0.75". The model spread suggests realistic low amounts in the 0.25" to 0.5" will probably occur, along with winners receiving near or even a bit more than an inch of rain in localized areas.
Cessation of rain Wednesday morning, and those higher end amounts, remain a point of contention related to two camps of model guidance. Either rain will be exiting the region, or another wave of soaking rain could move across most or all of the Adirondacks and much of Vermont before ending Wednesday afternoon. The GFS continues to depict a lagging trough and shortwave emerging from the central US to force widespread rain mainly in our southern areas. And yet, probability of measurable rain after 8 AM is only as high as 30%, so most guidance at this time suggests this outcome is unlikely. What is likely is much cooler conditions will settle into northern New York and Vermont during the day. A brief period of gusty north winds will be possible, especially on Lake Champlain which would produce rough seas. Temperatures could be about 20 degrees lower during the afternoon than 24 hours prior.
Another round of frost and freeze headlines then will be needed Wednesday night, and possibly Thursday night, as dry and seasonably chilly air will be present. Ensemble mean 925 millibar winds Wednesday night show flow will be diminishing aloft in northern New York, but relatively strong farther east as the high pressure area approaches and then crests over the area during the day Thursday. Then in contrast, as the high moves to the east, low level winds Thursday night will pick up in northern New York and be lightest in the Upper Valley in Vermont, suggesting a chillier night in eastern Vermont than Wednesday night when a freeze is more likely.
Due to the expected light winds through this period and recent rain, fire weather concerns will temporarily be low. Thereafter, Friday looks like a potentially breezy day ahead of another cold front. Would expect good channeling and we`ll possibly see lake wind advisory conditions for Lake Champlain. With southerly flow, maximum wind gusts above 25 MPH are favored in the northern Adirondacks, northern Champlain Valley, and St. Lawrence Valley where current probabilities are 30-60%. Early indicators for minimum relative humidity are for values to drop into the 35-45% range, with a pattern broadly similar to what we will see on Monday but with a much cooler air mass.
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.AVIATION /23Z SATURDAY THROUGH THURSDAY/... Through 00Z Monday...VFR conditions will persist through the evening. Patchy fog will develop later in the night and confidence has increased a little in it having wider coverage. It is possible at MPV and SLK, with maybe a 70 percent chance for it forming at MPV and maybe a 40 percent chance of it forming at SLK. The fog lifts quickly after sunrise and VFR conditions will persist for the rest of the day. Winds will be light and terrain driven this evening, before becoming southerly to southwesterly during the day tomorrow. Speeds up to 10 KTs are expected, except at BTV and PBG where gusts up to 15 KTs are possible.
Outlook...
Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: Mainly VFR, with local MVFR possible. Definite SHRA, Slight chance TSRA. Tuesday Night: Mainly VFR, with areas MVFR possible. Definite SHRA. Wednesday: Mainly VFR, with local IFR possible. Slight chance SHRA. Wednesday Night: VFR. Patchy frost. Thursday: VFR. NO SIG WX.
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.CLIMATE... Incoming heat this weekend is presently forecast to approach daily record values. The most likely dates for records will be Sunday October 5th and Monday October 6th. Below are some of the daily records in jeopardy of being broken (current forecast at or within 3 degrees of the record).
Record High Temperatures:
October 5: KBTV: 83/2023 KMPV: 82/1951 KPBG: 80/2005 KMSS: 85/1991 KSLK: 83/2023
October 6: KBTV: 82/1990 KMPV: 79/1990 KMSS: 81/2005 KSLK: 80/1946
Record High Minimum Temperatures:
October 5: KPBG: 56/1973
October 6: KBTV: 64/1937
October 7: KBTV: 62/1947
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.BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None.
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$$ SYNOPSIS...Danzig NEAR TERM...Danzig SHORT TERM...Danzig LONG TERM...Kutikoff AVIATION...Myskowski CLIMATE...BTV
NWS BTV Office Area Forecast Discussion