Area Forecast Discussion
Issued by NWS Burlington, VT
Issued by NWS Burlington, VT
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593 FXUS61 KBTV 271048 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 648 AM EDT Fri Sep 27 2024 .SYNOPSIS... Dry weather will prevail into the start of next week with temperatures a bit above climatological normals. Fog development is likely overnight in the typical valleys. The next chance of rain is mid-week as a cold front moves through. Overall, it will be a pleasant stretch of fall weather. && .NEAR TERM /THROUGH SATURDAY/... As of 641 AM EDT Friday... Fog has continued to expand this morning except across parts of the Northeast Kingdom where some mid-level clouds have moved in from Canada. The low stratus deck in the Champlain Valley has prevented temperatures from dropping as low as expected so had to raise temperatures there slightly. High pressure is building in and has pushed the rest of the high clouds associated with yesterday`s low south of the region. They should stay there through the day today. Overall, the forecast is in good shape and few edits were made. Previous Forecast...Extensive fog and low stratus have developed overnight. On top of being fog season, they were helped by yeaterday`s rain and a lack of boundary layer wind to scour out the moisture. The fog and stratus have developed across the climatologically favored valleys and also in other areas like much of the Champlain Valley. Winds aloft will only decrease as the night goes on and skies should remain mostly clear, so they should continue to develop and spread. Temperatures have been steadily dropping but the development of the fog and stratus has slowed the rate of decrease a little. Temperatures should still fall a couple more degrees by daybreak though. The upper level trough will continue to move out to the east today and ridging will build in. Surface high pressure will remain centered over eastern Canada and it will keep the remnants of Helene well to the southwest. Helene`s only impacts could be a few very thin high clouds. Sunny skies and a relatively warm airmass for the time of year will allow temperatures to rise into the upper 60s and mid 70s today. Clear skies and calm winds tonight will allow for another night of efficient radiational cooling. Fog will at least develop in the climatologically favored valleys, but whether it spreads outside of there areas remains to be seen as it will be a day removed from rainfall. Temperatures will fall into the 40s and low 50s. Saturday looks to be almost a copy of today, though temperatures will rise a couple degrees higher. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 344 AM EDT Friday...Little change in guidance this cycle with regards to large scale synoptic pattern which features building mid/upper lvl ridge over the northern Great Lakes into southern Canada, while remnants of Helene slowly weaken over the TN/OH Valleys. Using the progged IR satl feature from the GFS indicates intervals of high clouds are likely from time to time during this period. In addition, have noted both GFS/NAM soundings show additional lobes of moisture btwn 850mb and 700mb on Sat Night, which may limit areal coverage of fog. Otherwise, a 1020mb high pres nosing into our northern cwa, wl keep moisture associated with the remnants of Helene to our south and west thru the short term. Modest low level waa continues on Sunday into Monday, with progged 925mb temps btwn 16-18C, supporting highs well into the 70s on Sunday. Lows mainly in the 50s, with some cooler 40s in deeper mtn valleys likely. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 344 AM EDT Friday...Overall a very quiet with minimal impactful/hazardous wx for the next 4 to 7 days. Still have 50 to 60% pops for weak frontal passage on Tues night into Weds. As this system becomes closer in time, we should be able to narrow timing of precip to a 3 to 6 hour window from west to east acrs our cwa. GFS is very progressive with moving boundary acrs our fa, while ECMWF tries to advect lingering moisture from mid/upper lvl cyclonic circulation over the Ohio Valley into our cwa on Tues into Weds. This would produce a longer duration of precip, with some slightly higher qpf amounts. PW values range btwn 1.2 and 1.4" on Tues/Weds ahead of boundary with favorable jet structure at 250mb for promoting large scale synoptic ascent. If these ingredients combined with low level convergence along boundary continue to be present with upcoming system, pops wl need to be increased. In addition, still some uncertainty on timing, but once our guidance fine tunes the timing, confidence wl increase, resulting in some higher pops in the categorical (80-90%) range late Tues into Weds time frame. Llvl caa behind this boundary is modest, so most of the cooler temps wl be driven by the increasing clouds/precip on Tues/Weds, with temps mostly in the 60s. However, southerly flow ahead of this wl help advect much above normal temps into our cwa on Sunday/Monday with highs well into the 70s to near 80F. Lows generally in the upper 40s to upper 50s, cool back into the upper 30s to upper 40s by Weds and Thurs nights. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... Through 06Z Saturday... Widespread fog and low stratus have developed this evening and they will expand in coverage as the night goes on. Every terminal should see periods of IFR conditions and it is likely to be consistent except at PBG and MSS. The fog/stratus will lift at all terminals by mid-morning and VFR conditions will persist for the rest of the day. Winds will be mostly calm overnight, before increasing a little during the day and becoming northwesterly. Winds will go light tonight. Fog will develop tonight as well, at least at MPV, EFK and SLK, but possibly elsewhere as well. Outlook... Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: Mainly VFR, with local MVFR possible. NO SIG WX. Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: VFR. Slight chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Myskowski NEAR TERM...Myskowski SHORT TERM...Taber LONG TERM...Taber AVIATION...Myskowski