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Area forecast discussion 
National Weather Service Taunton Massachusetts 
425 am EST Thursday Jan 8 2009 


Synopsis... 
two areas of low pressure will consolidate over the Maritimes by early 
Thursday bringing strong westerly winds and drier conditions. Cold high 
pressure will build into New England Friday. The next winter storm will 
likely affect the region sometime Sat into Sat night followed by cold 
and dry conditions Sunday. Another precipitation event is possible 
late Monday or Tuesday...then cold temperatures set in on Wednesday. 


&& 


Near term /until 6 PM this evening/... 
low pressure from Wednesday now near Nova Scotia...and still moving 
northeast. Southwest to west on backside of this system now starting 
to increase in speed as strong low level cold air advection gets 
going. Scattered snow showers also accompanying this initial surge of 
colder air...but should be much of a concern after daybreak for most 
of southern New England due to a lack of low level moisture. 
Expecting mainly clouds today with broad middle level trough overhead... 
but kept a chance of showers across portions of northwest Massachusetts and 
southern New Hampshire where some moisture from the Great Lakes may spill over 
the Berkshires and Green Mountains. 


GFS MOS guidance looks to be too high today given the low level cold 
advection. Followed the lower FWC/met guidance instead. 


Have kept wind advisories and high wind warnings in place...although 
the timing looks to be a bit later. Mixing already beginning...and 
should increase dramatically after sunrise. Kbox 88d VAD wind profile 
not showing winds in excess of 45 knots until about 3000 feet above ground level...which 
is very reachable later this morning. May need to hold onto these 
wind advisories and warnings later in the day...but will monitor for now. 


&& 


Short term /6 PM this evening through 6 am Friday/... 
relatively tranquil weather tonight with diminishing winds and 
gradually clearing skies. Will be cold one through...with low 
temperatures in the teens. 


&& 


Long term /Friday through Wednesday/... 
Friday...the upper level trough will shift east of southern New 
England and cold high pressure will build in. While highs will be 
in the middle 20s to around 30...westerly winds gusting to around 25 
miles per hour will lower the feels like temperature down into the single 
digits to teens. Snow should not start until Saturday...however 
there is such a discrepancy in the models /see below/ that we 
started slight chance probability of precipitation late Friday night to account for that 
uncertainty. 


Saturday into Sunday...another upper level trough approaches from the 
Great Lakes while the associated surface low moves across the Ohio 
Valley. The models differ on the path and speed of the surface low 
from there on out. Based on HPC guidance and discussion with other 
offices it looks like the slightly slower European model (ecmwf) timing and the track 
of the GFS is the best solution for the time being. That track will 
take the low through the middle-Atlantic and then northeast passing 
just to the southeast of the 40/70 benchmark. This will result in 
snow overspreading much of the area with the heaviest snow falling 
south of the Mass Pike. While there is a good chance that snow will 
begin early to midday Saturday and continue through Sunday 
morning...the best chance of snow will be between 18z Saturday and 
06z Sunday. Highs will be similar both Saturday and Sunday 
generally ranging from the lower 20s to around freezing. Lows 
Saturday will range from the teens to around freezing then Sunday 
lows drop into the single digits to the middle teens. Any lingering 
snow should move out of the area by Sunday evening. 


Beyond Monday...disagreement amongst the models is greater. Monday 
and Tuesday...yet another upper level trough approaches from the 
west and moves through the area. This time the associated low 
pressure system moves through southern Canada. As it approaches...a 
warm front may move through southern New England Monday night. Warm 
advection precipitation is likely with this system though timing of 
the onset of precipitation is uncertain. At this point...it does look like 
precipitation that falls will be snow with a possible mix out on the 
cape and islands. With the warm front moving through Monday 
night...highs on Tuesday will likely be fairly early in the morning 
before temperatures drop with a cold frontal passage. This front 
will usher in much colder airmass. Wednesday...strong...cold high 
pressure builds in behind the cold front. Highs are expected only 
to be in the teens to lower 20s. 


&& 


Aviation /09z Thursday through Monday/... 
widely varying conditions this morning running from IFR in low clouds 
and scattered snow showers...all the way to VFR in spots early this 
morning. Expecting VFR conditions to become more widespread by middle 
morning. 


Strong low level cold air advection this morning will result in a 
strengthening west to southwest winds. Strongest gusts will be after 
daybreak. 


VFR tonight. 


Outlook /Friday through Monday/... 


Friday...VFR. 


Saturday...VFR diminishing quickly from west to east to MVFR/IFR in 
snow. Heaviest snow expected to fall south of Mass Pike. 


Sunday...conditions improve to VFR. 


Monday...MVFR/IFR conditions possible in -sn with approaching warm 
front. 


&& 


Marine... 
maintained existing storm and gale warnings...although timing now 
appears to eb a bit later. Model soundings still show potential for 
gusts up to 50 kts across some of the waters later this morning. At 
least gale force wind gusts likely across the waters through this 
afternoon into tonight. Seas building up to 15 feet across the outer 
south coastal waters today. 


Outlook...Friday through Monday... 


Friday...seas decrease gradually through the day with lingering 5 
foot seas across the outer waters. Westerly winds 20 to 30 knots 
gusting up to 33 knots at times. Chance of light freezing spray. 


Saturday...seas decrease through the day and then increase again 
during the evening hours with the approach of a coastal low. 
Westerly winds 10 to 15 knots early on switch around to the northeast 
in the afternoon increasing to 25 to 35 knots after midnight. Chance 
of light freezing spray. 


Sunday...seas decrease gradually falling below 5 feet by early Monday 
morning. Northeasterly winds 25 to 35 knots shift around to the 
northwest and decrease after noon. Chance of light freezing spray. 


Monday...seas begin to increase towards the evening hours as a warm 
front approaches the waters. Westerly winds 10 to 15 knots shift 
around to the south and increase to 15 to 25 knots. 


&& 


Box watches/warnings/advisories... 
CT...none. 
Massachusetts...High Wind Warning until noon EST today for maz022>024. 
Wind Advisory until noon EST today for maz016>021. 
New Hampshire...none. 
Rhode Island...High Wind Warning until noon EST today for riz008. 
Wind Advisory until noon EST today for riz002-004>007. 
Marine...Storm Warning until noon EST today for anz232>235-254-255. 
Gale Warning until 5 PM EST this afternoon for anz230. 
Gale Warning until midnight EST tonight for anz231-250. 
Gale Warning until 7 PM EST this evening for anz236-237. 


&& 


$$ 
Synopsis...rlg 
near term...Belk 
short term...Belk 
long term...rlg 
aviation...Belk/rlg 
marine...Belk/rlg 

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