May 14, 2010

Hydromet Outlook through May 28th and a 2 month Hindcast
Two week outlook:
The general weather pattern across the Northeast during the next week
will feature below normal precipitation with little in the way of northeast
flow in the Gulf of Maine.    A weather system, similar to the past two events
this week, will push a front through the region around the 19th but most
of the rain associated with this system will fall over southwest New England.

During week two (May 23-28) there is quite a bit of uncertainty in the overall
weather pattern.   A rather large area of cool Canadian high pressure is expected
to form over the Canadian high plains then eventually drop southeast to our region
of the country.   This type of pattern can produce a more prolonged period of northeast
winds between May 23 and 26 but there is little signal supporting heavy rainfall preceding this system.

Hindcast discussion for March/April 2010:

In hindcast, the 1000 mb wind anomaly analyzed for the month of March
indicated a classic northeast flow regime with a large area of +3 m/s for the month. This flow regime was accompanied by above normal rainfall. March rainfall departures were
generally 2 to 5 inches above normal across Maine, increasing to a robust 8 to 15 inches
above normal from extreme southwest Maine through southeast New England.   These departures were of a lower order for most of Maine when compared to the recent large HAB events
in the past 5 years.

For April - a dramatic shift to a northwest flow regime took place.     Since then, rainfall has been below normal ranging from 1 inch below normal in far northern Maine to as much as 3 to 4 inches below normal across the coastal counties of eastern New England.

Last updated: May 20, 2010