textproduct: Burlington

WHAT HAS CHANGED

As of 325 PM EDT Wednesday...

No significant changes have been made to the forecast.

KEY MESSAGES

As of 325 PM EDT Wednesday...

1. Potentially active weather day Thursday as deep moisture and some surface based instability will lead to thunderstorm development.

2. Shower and thunderstorm potential continues on Friday and Saturday.

3. Following a seasonably warm and humid period, drier air will arrive by the middle of next week.

DISCUSSION

As of 325 PM EDT Wednesday...

KEY MESSAGE 1: Strong heating during the afternoon hours on Thursday leads to decent surface based instability for our region. Upper level shortwave activity will help to sustain some showers and thunderstorm activity during the afternoon especially. Maximum temperatures will be in the 80s with dewpoint temperatures in the 70s, leading to CAPE in excess of 1000 J/kg. Not a lot of deep layer shear present, but higher mid level winds associated with trough to the west will help some storms become better organized. Strong winds will be the main threat with any thunderstorms that become better organized. Timing for storms entering our northern New York zones will be around 1 pm, with storms exiting Vermont by 8 pm.

KEY MESSAGE 2: Heading into the end of this week, warm and unsettled weather is expected as the region remains sandwiched between high pressure to the south and an upper level trough to the north, with zonal flow bringing several different disturbances to the region. With broad southwesterly flow ushering in plenty of moisture, chances for showers and thunderstorms will be possible. There will not be a defined boundary to help drive shower activity, though the shortwave activity Friday and Saturday may provide enough energy to drive afternoon shower and thunderstorm chances. If ingredients align, there could be the potential for some stronger thunderstorms both afternoons, but generally more garden-variety thunderstorms can be expected. Shower activity is expected to wane towards the evenings with loss of diurnal heating. High temperatures will rise into the mid to upper 80s with dewpoints around 70 degrees, resulting in heat indices in the upper 80s to around 90.

KEY MESSAGE 3: Sunday into Monday it appears the Bermuda high will weaken and become suppressed a little farther south and east. As such, more westerly flow will prevail with less humidity than what will be in place through Saturday. While temperatures will remain on the warm side of normal, the air mass will no longer be muggy and precipitation chances are relatively low through Monday morning. Sometime in the later Monday or Tuesday timeframe, a cold front will zip eastward and bring widespread showers and perhaps some thunderstorms, especially if the frontal passage holds off until the daytime on Tuesday. The later timing and much greater instability depicted in one model cluster/scenario, which is consistent with the 12Z ECMWF, does pose a severe weather threat. At this time, the consensus is Tuesday morning, which limits the risk of impactful weather. Per ensemble guidance, below normal precipitable water will return on Wednesday following a brief surge of deeper moisture on Tuesday.

AVIATION /01Z THURSDAY THROUGH MONDAY/

Through 00Z Friday...VFR conditions are expected to prevail through much of this forecast period with best chances of flight degradation to CIG/VIS coming 18-00Z with periods of showers and a lower chance of thunderstorms. For now, kept 30% probabilities and VCSH in the forecast to highlight this potential. Otherwise, fog chances are low tonight. Flow tomorrow remains light out of the south/southwest.

Outlook...

Thursday Night: VFR. Isolated SHRA, Isolated TSRA. Friday: VFR. Scattered SHRA, Scattered TSRA. Friday Night: VFR. Chance SHRA, Slight chance TSRA. Saturday: Mainly VFR, with local MVFR possible. Likely SHRA, Chance TSRA. Saturday Night: VFR. Chance SHRA, Slight chance TSRA. Sunday: Mainly VFR, with local MVFR possible. Slight chance SHRA, Slight chance TSRA. Sunday Night: VFR. Slight chance SHRA, Slight chance TSRA. Monday: VFR. Chance SHRA, Slight chance TSRA.

BTV WATCHES/WARNINGS/ADVISORIES

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