Epi Week #40 - 2015 General Statements

Mosquito activity is definitely ramping down for the season, as temperatures continue to drop. There were only 3 new WNV+ mosquito pools this week, bringing the total for the season to 164. Of the 3 pools, 2 were from Boston and in the Culex pipiens/restuans complex, and 1 was from Westborough (Worcester County) and was Culiseta melanura. No further EEEv activity was detected. Mosquito surveillance is minimal across the districts/projects, with no treatment operations currently in effect.

Weather

After a week with significant precipitation, the rainfall map is back to pale yellow, with accumulation across the state all well below an inch.

Expect a gradual cool down over Epi Week 41, until a cold snap hits over the weekend that will bring daytime highs down to the low 40s. If winds go calm in the interior of the state, we could easily see many locations bottom out with upper 20s for overnight lows, which would guarantee a killing freeze. Even if the winds do not go calm, temperatures will still average 30-34F, which is plenty low enough for our first widespread frost. That said, we will not “lock-in” to this cold and should return to above normal temperatures by the middle/late part of Epi Week 42.