Area Forecast Discussion
Issued by NWS Burlington, VT

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379 FXUS61 KBTV 220641 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 241 AM EDT Thu Jun 22 2017 .SYNOPSIS... High pressure will build into the region tonight into Thursday with dry and seasonably pleasant weather expected. Showers and thunderstorms return to the region by Friday into Friday night with locally heavy rainfall possible. A brief return to dry weather is expected on Saturday before more showers return for the early portions of next week. && .NEAR TERM /UNTIL 3 PM THIS AFTERNOON/... As of 156 AM EDT Thursday...Generally quiet conditions anticipated through the rest of the overnight hours. The showers from the mid level wave have come to an end with only a few clouds remain. Temps continue to slowly fall with upper 40s to mid 50s looking good for lows. The forecast has this covered well and no changes were necessary this morning. Previous discussion...Showers associated with mid-level trough greatly diminishing, with only isolated showers lingering. Diurnally driven cumulus clouds also decreasing in coverage, leaving only some clouds with embedded shortwave in the mid level troughy flow slowly diminishing as well. Can`t rule out isolated to scattered areas of patchy mist/fog in favored locales in the 4-7 am time frame, but with a modest amount of mixing atop the nocturnal boundary later and given the overall short length of darkness widespread occurrence is not expected. Min temperatures generally ranging from upper 40s to mid 50s. Shortwave ridging builds quickly across the region on Thursday with dry weather and abundant sunshine through early to mid afternoon under light southerly flow. An increase in mid to high cloudiness will begin to push into northern NY counties by later in the day and toward evening in advance of a strengthening warm front approaching from the southwest. Modeled 925-850 mb thermal progs support high temperatures ranging through the 70s to locally near 80 in the broader Vermont valleys. Sensible weather trends inclement by Thursday night as aforementioned warm front pushes into the area. Robust moisture advection and isentropic lift on the nose of robust southwesterly flow in the 850-500 mb layer will foster increasing chances of showers and a few thunderstorms, mainly after midnight across northern NY and toward dawn across eastern VT counties. Perusal of modeled QPF fields suggests the best forcing should occur across our central and northern counties and as such have offered highest pops in this area where totals from a quarter to one half inch will be possible by sunrise Friday. Lows trend quite mild with continued south/southwesterly flow and increasing clouds - upper 50s to mid 60s. && .SHORT TERM /3 PM THIS AFTERNOON THROUGH 6 PM FRIDAY/... As of 322 PM EDT Wednesday...Heavy rainfall and isolated severe storms are the main stories for Friday. SHRA/TSRA activity to continue both Friday and Friday night. Model consensus PW values in excess of 1.5" approaching 2" in some areas, along with deep warm cloud depth will lead to convective activity being very rainfall efficient. Can`t pin down any one location to suggest an enhanced risk of flooding and overall the system is fairly progressive so no watches at this time. Isolated severe also possible with 0-6km deep-layer shear values of 30-40kt would suggest organized convection possible given a sufficient amount of instability is able to be realized. Good veering in the low levels in model profiles leaving fairly large low level hodographs so can`t rule out a supercell, again, given sufficient instability. Saturated and warm profiles suggest hail potential is minimal, and primary risk would be damaging winds. In the wake of the retreating warm front, there still appears to be a fair amount of cloud cover and shower activity so despite models indicating higher CAPE numbers, feel that we`ll probably only be able to realize 500-100 j/kg MLCAPE at best. We`ll have to see what light can shed by newer guidance on the evolution of cloud cover and shower activity for the early part of Friday and its attendant effect on convective evolution of the day. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... As of 322 PM EDT Wednesday...SHRA/TSRA activity with heavy rainfall risk continues for the early part of Friday night before organized activity moves east early Saturday. Broad upper level trof remains over the Great Lakes and northeast into the middle part of next week. Can`t really find any one period in the extended that will be completely dry with cyclonic flow aloft and weak shortwaves rotating around the base of the trof. SHRA chances will continue in the forecast through the period. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... Through 06Z Friday...VFR conditions expected through the rest of the overnight and into Thursday afternoon. Clouds will begin building into the north country this afternoon as a warm front will bring rain showers to the northern taf sites shortly after 00z Friday. Choose to offer VCSH for all sites with prevailing -SHRA between 01-03z for BTV/PBG/MSS/SLK. Winds light WSW turn more SW tomorrow. Outlook... Friday: VFR/MVFR. Breezy. Likely SHRA...Slight chance TSRA. Friday Night:VFR/MVFR. Likely SHRA...Slight Chance TSRA. Saturday: VFR. Chance SHRA. Saturday Night: VFR. Slight Chance SHRA. Sunday: VFR. Chance SHRA...Slight Chance TSRA. Sunday Night: VFR. Chance SHRA...Slight Chance TSRA. Monday: VFR. Chance SHRA...Slight Chance TSRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...Deal/KGM/JMG SHORT TERM...Manning LONG TERM...Manning AVIATION...Deal is the U.S. government's official web portal to all federal, state and local government web resources and services.