878 
fxus61 kbox 191451 
afdbox 


Area forecast discussion 
National Weather Service Taunton Massachusetts 
950 am EST Wednesday Nov 19 2008 


Synopsis... 
persistent low pressure well to our northeast will combine with a 
high pressure system across the Great Lakes and Midwest to bring 
unseasonably cold air to southern New England into next weekend. 
Little in the way of measurable precipitation is expected...but rain 
or snow showers are possible Monday into Tuesday as low pressure 
tracks over southern New England. 


&& 


Near term /until 6 PM this evening/... 
band of briefly heavy ocean effect snow showers developed over the 
Middle Cape to Nantucket since 11z. Models seemed to handle of 
maximized lapse rates at around sunrise pretty well...which was when 
the precipitation picked up. Updated zones and grids to reflect this...and 
put in likely to categorical probability of precipitation along with a bit more quantitative precipitation forecast. At 
14z...appears that the precipitation may be waning with a band shifting a 
bit further east toward the Outer Cape. May see precipitation pulse back up 
again through midday. Once winds back to northwest...will see precipitation shrink 
and shift east. 


Offshore low pressure will gradually move away from southern New 
England today. Mainly fair skies but anomalously cold temperatures 
will be left in the storm/S wake. Highs today will average a good 10 
to 15 degrees below normal...and wind chill values will make it feel 
quite a bit colder. 


Expect the Wind Advisory to expire at 10 am. Still expect gusts up 
to 30 miles per hour mainly over the cape and islands. 


&& 


Short term /6 PM this evening through 6 PM Thursday/... 
diminishing winds and cold temperatures tonight. Next short wave approaches 
from the west...and this should spread clouds into southern New England from west to 
east after midnight. The arrival time will have an impact on low 
temperatures. A faster arrival will likely mean slightly higher mins than 
forecast. 


Short wave trough rotates overhead during the day on Thursday. 
Cloudy/mostly cloudy skies are expected. Moisture may be deep enough 
for a time to allow for a few flurries. Temperatures will once again be much 
colder than normal. Forecasted highs could even be too 
high...especially if thick cloud cover persists all day. Wouldn/T be 
completely shocked in most southern New England locations have a hard time breaking 
freezing if that/S the case. 


&& 


Long term /Thursday night through Tuesday/... 
northwest flow regime persists into weekend as another upper trough rotates 
through region. This should focus any precipitation offshore but it 
is possible for flurries/sprinkles across interior as well. Otherwise 
should be plenty of diurnal cloudiness Friday and Sat with such cold air 
aloft. High pressure builds overhead sun...but temperatures will be 
slow to recover with 850 mb temperatures as cold as -8 to -12c. 


00z models diverge significantly at this point as differences evolve 
in middle level flow pattern over Continental U.S.. European model (ecmwf) cuts off upper low over 
east which results in one low tracking over southern New England Tuesday 
followed by a much more anomalous system forming well off middle 
Atlantic coast middle to late week. GFS remains more progressive and 
brings initial system through about a day faster...before second one 
passes well out to sea. 


We still prefer slower European model (ecmwf) solution as it has gefs support and 
makes more sense given digging upper trough. Therefore we will 
introduce chance probability of precipitation Monday afternoon into Tuesday...and it should be noted 
that it may be cold enough at onset across interior for snow showers. 


At this point we will lean more on ensembles Tuesday and indicate 
improving conditions in west/northwest flow regime. 


&& 


Aviation /15z Wednesday through Sunday/... 
MVFR kfmh/khya/kack in ocean effect snow bands through 16z... 
otherwise VFR today. North winds gusting to 25-30kt kbos to kack with 
strongest gusts this morning. 


VFR with quickly diminishing winds tonight. VFR Thursday. 


Outlook...Thursday night through Sunday... 


VFR. Gusty northwest surface winds to 30kt possible Friday night into Sat. 


&& 


Marine... 
have downgraded the Gale Warning on the south sounds to a small 
craft. Winds gusting to around 30 knots at Buzzards Bay buoy...and will 
continue to slowly diminish this afternoon. 


Kept gale warnings remain through the afternoon for the outer waters 
as well as Cape Cod Bay and Nantucket Sound. Will keep an eye on 
this in case winds diminish a bit quicker than currently thinking. 
Will convert to small crafts when the time comes. Seas will remain 
high before subsiding later tonight and Thursday. 


Outlook...Thursday night through Sunday... 


Potential for marginal northwest gales Friday night into Sat...especially on 
outer waters. Models at face value show 40kt gusts possible but we 
capped at 35 knots given low confidence. Winds and seas diminish sun as 
high pressure builds into region. 


&& 


Box watches/warnings/advisories... 
CT...none. 
Massachusetts...Wind Advisory until 10 am EST this morning for maz022-024. 
New Hampshire...none. 
Rhode Island...none. 
Marine...Gale Warning until 4 PM EST this afternoon for anz231- 
232-250-254-255. 
Small Craft Advisory until 7 PM EST this evening for anz230- 
233>237. 


&& 


$$ 
Synopsis...ekster 
near term...evt 
short term...ekster 
long term...jwd 
aviation...ekster/jwd 
marine...ekster/evt/jwd