The numerical models are gradually working toward a consensus concerning the
evolution of the 500MB longwave pattern. With the powerful heat ridge shifting
away from the Greater Antilles into the Sargasso Sea (just southeast of
Bermuda), and the very deep Arctic vortices locking in across the Aleutian
Islands and northern Nunavut AR, the stage is set for a fairly vigorous split
flow configuration through the U.S.

Ignore the system ejecting from northern Mexico in the southern branch; headed
into confluence over the Atlantic Ocean by Days 6/7 and not a threat for the
Northeast. Instead, follow the storm sequence emerging over the Pacific Ocean,
which digs into CA and then works through the lower 48 states during the latter
half of next week (example: see ECMWF link below

http://www.ecmwf.int/products/foreca...ic/world/msl_u
v850_z500!Geopotential%20500%20hPa!168!North%20Ame rica!12!pop!od!oper!publ
ic_plots!latest!/

With no cold air to speak of (contained with northern stream in Canada), the
newest low should track as an important rainmaker from the lower Great Plains
into southern New England between February 18 and 21. There may be some
potential for ice in interior NY....VT....NH....ME through parts of the QC
Eastern Townships into N Br. But the major threat would be heavy rainfall and
runoff (severe thunderstorms a concern in the Deep South), since the
aforementioned subtropical high may allow for a deep moisture fetch (mTw
values) from the Caribbean Sea and Gulf of Mexico into the cyclone.

Best Regards,
Larry Cosgrove


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