WPC Met Watch

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Mesoscale Precipitation Discussion: #0394 (Issued at 1206 PM EDT Sat Jun 07 2025 )
MPD Selection

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Mesoscale Precipitation Discussion 0394 NWS Weather Prediction Center College Park MD 1206 PM EDT Sat Jun 07 2025 Areas affected...Far Northeast PA...Northern NJ...Southeast NY...Central and Southern New England Concerning...Heavy rainfall...Flash flooding likely Valid 071600Z - 072200Z SUMMARY...Heavy rainfall will continue to overspread much of the northeast Mid-Atlantic region into central and southern New England going through the mid to late-afternoon hours. This will include some locally more concentrated areas of stronger thunderstorm activity with higher rainfall rates. Areas of flash flooding are likely considering the very moist and locally saturated soil conditions. DISCUSSION...An expansive axis of heavy rainfall in a southwest to northeast fashion continues to advance across southeast NY and into central and southern New England. The activity which includes some occasionally stronger thunderstorm activity continues to be strongly supported by an ejecting shortwave trough and associated wave of low pressure which is transiting a well-defined frontal zone across the Northeast. The latest GOES-E IR/WV satellite imagery shows an excellent corridor of upper-level jet divergence/forcing over especially central and southern New England with an expansive axis of cooling cloud-tops over the region. There continues to be a low-level frontogenetic response to this with the axis of heavy rainfall which has been very efficient this morning. Shallow, warm convective tops and frontogenetical forcing in the lower to mid-levels of the column have been yielding warm rain processes, and this showed up well in the 12Z ALY RAOB sounding which depicted a deep moist column with a tall/skinny CAPE profile. There should be a gradual uptick in the overall convective footprint of the heavy rainfall this afternoon across especially southern New England including the Boston, MA to Hartford, CT corridor and potentially edging south to near the New York City metropolitan area and adjacent areas of northern NJ by late afternoon. This will be supported by convergence along the aforementioned frontal zone, but also with an increase in diurnally driven instability. Cloud cover will tend to mitigate the amount of surface heating that does occur, but with an already very moist column, and the aforementioned low-level and upper-level support, there should be a gradual expansion of heavier showers and thunderstorms over the next several hours. Rainfall rates may reach as high as 1.5 inches to 2 inches/hour with the stronger cells, and the locally slow cell-motions and pockets of at least brief cell-training may support some totals by early this evening that reach 3 to 4+ inches. This is supported by the 12Z HREF and 06Z REFS guidance. The antecedent conditions are quite sensitive over the higher terrain of southern VT, southern NH and through central and western MA. Runoff here over the next few hours may be enhanced given the additional rains, and gradually heavier rainfall rates farther south and east may pose some urban flooding concerns. Overall, on a regional level, areas of flash flooding are likely. Orrison ATTN...WFO...ALY...BGM...BOX...BTV...GYX...OKX...PHI... ATTN...RFC...RHA...TAR...NWC... LAT...LON 44607027 44566903 43996893 42937041 41747132 41217275 40987314 40527430 40537520 41047545 41917467 42717390 43727193 

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Last Updated: 1206 PM EDT Sat Jun 07 2025