textproduct: Burlington

WHAT HAS CHANGED

As of 242 PM EDT Friday...

No significant changes made with this forecast update.

KEY MESSAGES

As of 242 PM EDT Friday...

1. Daily chances for showers and afternoon thunderstorms with potential for localized moderate rainfall.

2. Limited shower and thunderstorm chances from Tuesday into Wednesday become more likely on Thursday and Friday. Systems look weak with modest moisture such that significant rain, wind, or severe weather is unlikely.

DISCUSSION

As of 242 PM EDT Friday...

KEY MESSAGE 1: Flow has become increasingly blocked downstream while low pressure centered over eastern Canada has become increasingly barotropic. This will result in a lingering patter of cyclonic flow aloft with intermittent shortwaves moving through the region bring showers and chances for thunderstorms.

Showers are evident along a convergent line slowly dropping south out of Canada this afternoon and will continue to move through the region this evening and overnight. There is potential for moderate rainfall in some shower/thunderstorm elements which could lead to localized rainfall near 1 inch. however, most locations will see only a few hundredths to less than 0.25". Northern Vermont seems to be in a favorable spot for some instability lingering this evening coincident with timing of the convergent line to move through. This will promote rainfall totals in the 0.25-0.5" range. As such, river rises are possible again on the Missisquoi River while falling waters on the Barton River may stall somewhat. No further flooding is anticipated, but rainfall may be sufficient to keep drainages near bankful tonight. Breezes will continue this afternoon into Saturday with the pressure gradient remaining tighter than usual across the region; gusts 20-30 mph remain possible.

Northwest flow deepens Saturday with continued shower chances especially along terrain of northern Vermont. River flows in northern Vermont will likely remain elevated, but QPF amounts are generally expected to be lighter and less than 0.25".

After somewhat of a break Sunday with fewer showers, the next system will approach from a southwest trajectory promoting more stratiform rainfall. Models are a little split on how far north rainfall will progress with some keeping the system's track farther south with less isentropic lift across Vermont. However, enough members have rainfall pushing across central/southern Vermont to support likely chances at this time. Held off on thunderstorms for now since forcing will be directed south and along the relative warm front.

KEY MESSAGE 2: A couple of broad upper level troughs will traverse the region with only slight recovery of the low level air mass in between. As such, temperatures look fairly steady and near typical values for early summer with highs generally in the mid 70s to low 80s with lows in the 50s to low 60s. Subtle shortwaves in the cyclonic flow could line up with daytime heating to enhance risk of thunderstorms, but given unimpressive dynamics and instability, strong or severe thunderstorms are unlikely through Wednesday.

The ensemble mean trough position looks more favorable for synoptic scale lift later in the week such that spatial coverage of showers and thunderstorms will likely be higher on these days than earlier in the week. One indicator of strong thunderstorm potential, the joint probability of SB CAPE > 500 J/kg and bulk wind shear greater than 30 knots, shows some signal in the latest ensemble guidance, particularly if the incoming trough is a little more amplified than the ensemble mean. Overall, better dynamics for thunderstorms may set up on either or both of these days such that they will need to be monitored for a stronger storm or two. Still, widespread significant weather is not expected with this weather pattern.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Through 00Z Sunday...A mix of MVFR and VFR conditions currently prevail across the region as a band of showers continue to move across the region, with conditions variable due to changing visibilities and ceilings within showers. Lower ceilings are expected after 09Z or so, with most terminals observing a period of MVFR ceilings, with some IFR stratus development possible at KSLK. Winds will continue to remain breezy throughout the forecast period, although gusts are expected to lessen a bit during the overnight hours before picking up again in the morning. Winds are currently westerly, but are expected to become more northwesterly throughout the period. Some LLWS will be possible at KSLK through about 09Z or so.

Outlook...

Saturday Night: VFR. Chance SHRA, Slight chance TSRA. Sunday: Mainly VFR, with local MVFR possible. Definite SHRA, Chance TSRA. Sunday Night: VFR. NO SIG WX. Monday: VFR. Chance SHRA. Monday Night: VFR. Chance SHRA, Slight chance TSRA. Tuesday: VFR. Chance SHRA. Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. Slight chance SHRA, Slight chance TSRA.

CLIMATE

As of 308 PM EDT Thursday... Daily record precipitation of 1.22 inches was achieved for the Saranac Lake Area yesterday, breaking the 1924 record of 0.87 inches.

BTV WATCHES/WARNINGS/ADVISORIES

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