textproduct: Burlington

WHAT HAS CHANGED

As of 230 PM EDT Thursday...

No significant changes to the current forecast.

KEY MESSAGES

As of 230 PM EDT Thursday...

1. Near critical fire weather conditions will continue through this afternoon/evening before slightly recovering tonight. Dry conditions will continue for parts of southern Vermont tomorrow ahead of a frontal system.

2. A frontal passage on Friday continues to favor a wetting rainfall for most of the area, with seasonable conditions behind the front for the weekend.

3. Several precipitation chances in the forecast next week with warm conditions expected.

DISCUSSION

As of 230 PM EDT Thursday...

KEY MESSAGE 1: The combination of observed low relative humidities across the area between 15-25%, with localized gusts in the Champlain Valley as high as 45 mph and receptive fuels will keep the Champlain Valley and St. Lawrence Valley in an elevated fire weather concern through this afternoon and evening before relative humidities somewhat recover tonight. A Special Weather Statement remains in effect for the Champlain and St. Lawrence Valley through 6 PM this evening for near critical fire weather conditions, in coordination with partners on fuel conditions.

High pressure will slide slowly eastward, keeping strong southerly flow and dry conditions across the area this afternoon into the evening. Steepening lapse rates from good vertical mixing today have led to localized wind gusts between 40-45 mph in the Champlain Valley, while elsewhere gusts have only been 25-35 mph. Winds should be peaking at the time of this discussion, but should begin to decrease as we near sunset. Beyond sunset, nocturnal cooling will help lower temperatures, and with some western moisture advection, wind gusts will weaken to 15-20 mph as a low level jet to 45-55 mph remains overhead as a frontal boundary approaches the region.

A frontal boundary will approach the region beginning this afternoon with a weak shortwave passage across the St. Lawrence Valley. Given how dry the area is any radar returns and subsequently possible precipitation will likely fall as virga, but should help moisten air columns lessening any fire weather concerns tonight into tomorrow. This boundary washes out overnight somewhere across north-central Vermont in a northeast- southwest axis. This will allow portions of southern Vermont, mainly in the Upper Valley of the Connecticut River to see continued dry conditions into tomorrow. While relative humidities may increase towards 60-70%, these poor recoveries will set the stage for low RHs again in southern Vermont. While not as pronounced as today, relative humidities may approach 35-40% in areas like Springfield, VT late tomorrow morning into early afternoon before the main cold front slides southeast tomorrow afternoon. The Champlain Valley tomorrow southward into Rutland, may see some lower relative humidities again as well between 35-50%, with lower values across Rutland County, though dewpoint depressions are not expected to be as large as today, and winds should be weaker, driven by weaker downsloping and less vertical mixing. Winds may increase to 15-20 mph in Windsor County tomorrow afternoon, but fire weather concerns will be limited.

KEY MESSAGE 2: A cold frontal system will approach the region Friday afternoon beginning across northern New York and sliding eastward across the entire region. GOES satellite depicts this feature developing across the central Plains. The front arrives by mid morning across northern New York with the passage of a weak warm front, with the main cold front traversing the area in the early to mid afternoon in northern New York and by the late afternoon/evening for Vermont.This system is NOT expected to be a soaker, but models do show the potential for some beneficial wetting rainfall between 0.1-0.4" across the region, helping to alleviate dry fine fuels, and reducing fire weather concerns into the weekend. High amounts between 0.25-0.4" are expected near the International Border with some mountain summits approaching 0.5". Hi-Res CAMs (like the HRRR) denote an area of enhanced precipitation potential across the southern Champlain Valley and western Rutland County where better frontal forcing and an increase low level jet will support some isolated convective elements. SBCAPE will only be around 150- 200J/kg, but with the presence of the front, this may be enough to support isolated convective elements. This system track does favor potential shadowing in the northern Champlain Valley and Windsor County where only 0.1-0.2" of rain is expected, less than surrounding areas.

The front quickly races east with precipitation tapering off for most by midnight Saturday as colder drier air from the northwest filters in. Across the Northeast Kingdom early Saturday morning, northwest flow may keep some low level moisture around as the mid level dry out, leading to some low- topped snow showers. Snow accumulations will be minimal if any with ground temperatures above freezing. Otherwise, Saturday will be on the chilly side, but mainly sunny side, with northwest caa and breezy conditions with highs in the low to mid 40s.

KEY MESSAGE 3: Surface high pressure will shift offshore on Sunday, with an expansive upper level high building over the Gulf of Mexico. A slow moving upper trough will amble east from the Rockies, but it will struggle to cause the upper high to budge. The longwave trough will eventually fade, but it will get replaced by a new one in time. Under this regime, we will be running warm within moist air mass as embedded systems eject northeastwards. Timing individual, smaller scale features will be challenging in this regime, but higher probabilities are focused on Sunday night into Monday, and perhaps Tuesday night into Wednesday. After that, the timing of systems begins to really diverge. By the middle of next week, temperatures will range in the upper 60s to mid 70s. Combined with sufficient moisture, convective instability will be possible. CPC's outlook towards the end of the extended indicate probabilities are leaning above normal into mid April for precipitation and likely above normal for temperatures.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Through 18Z Friday...VFR conditions are expected for the next 9-12 hours before lowering ceilings arrive. Some virga will be possible as showers approach the region, but the air below 5000 foot elevation will be very dry. If there's any chance for a sprinkle, it would be in the St. Lawrence Valley. By about 06z, increasing low- level moisture will result in some MVFR ceilings at KMSS, and perhaps KSLK. After 12z, spotty showers will be possible at KMSS and KSLK. Initial winds are gusty, mainly 10-20 knots sustained with gusts 18-27 knots, but KBTV has been especially gusty, occasionally reaching 35-43 knots. These winds will slowly abate. However, flow aloft will remain 35-45 knots, and so some LLWS is likely to develop overnight ahead of a frontal boundary approaching the St. Lawrence Valley about 12z, which will also start to drive a west to northwest wind shift beyond 18z Friday.

Outlook...

Friday Night: MVFR/IFR conditions possible. Likely SHRA. Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. Chance SHRA. Sunday Night: Mainly VFR, with local MVFR possible. Likely SHRA. Monday: Mainly MVFR, with areas VFR possible. Likely SHRA. Monday Night: Mainly MVFR, with local IFR possible. Chance SHRA. Tuesday: Mainly MVFR, with local IFR possible. Chance SHRA, Slight chance TSRA.

EQUIPMENT

The Colchester Reef meteorological station is out of service. This site is not serviced by the NWS. An estimated return to service is May 1st. Please contact us if you observe winds significantly deviating from the recreational forecast.

BTV WATCHES/WARNINGS/ADVISORIES

VT...None. NY...None.