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Area forecast discussion 
National Weather Service Taunton Massachusetts 
953 am EST Thursday Nov 5 2009 


Synopsis... 
a series of low pressure systems will track east with secondary low 
pressure developing off the middle Atlantic coast...well S of New England 
today. An upper level low will cross the region tonight followed by 
brisk northerly flow Friday as low pressure intensifies well east of New 
England. Large high pressure settles across the middle Atlantic coast 
this weekend...moving slowly out to sea early next week. A cold front 
moving east from the Ohio Valley may stall along the East Coast 
during the middle of next week. 


&& 


Near term /until 6 PM this evening/... 
made minor adjustments to temperatures and dewpoints to account for 
the latest trends. Also brought probability of precipitation down through noontime as light 
rainfall has exited the region and not expected until the next 
shortwave impacts US. 


A pair of shortwaves...one over the central Appalachians and the 
other over Lake Superior...should impact our region this afternoon. 
Weak 500 mb-7 cyclonic flow remains over the region but low level 
convergence and dynamical forcing mechanisms are not impressive 
today. Therefore lowered probability of precipitation to chance. 


A few breaks of sun will be possible in between shortwaves this 
morning...mainly across the southeastern zones. Noting some middle level 
drying from the latest water vapor satellite imagery. Otherwise it 
will remain chilly with highs in the upper 40s to lower 50s. 


&& 


Short term /6 PM this evening through 6 PM Friday/... 
tonight...a second more impressive short wave approaches from the 
Great Lakes region. This allows for the long wave trough to become 
more negatively tilted with an inverted trough axis extending 
northwest across the area. However phasing of subtropical moisture 
occurs too late as deeper moisture remains southeast of New England. 


The trend has been for a more progressive solution with low pressure 
developing further offshore. Therefore favored the more progressive 
00z GFS/European model (ecmwf) solutions versus the slower NAM which appears to be an 
outlier. 


Have included chance probability of precipitation as the 500 mb-7 upper level trough axes cross 
the region overnight. Vertical cross sections do not look favorably 
moist except along the southeast coast. Scattered rain showers should 
mix with and change to snow across much of the interior as 
temperatures cool aloft. Boundary layer temperatures remain 
generally too warm to support snow along the immediate coastline. 
Brief banding of precipitation could occur as the offshore low 
intensifies...though not well depicted at this time. Little if any 
wet snow accumulation is expected. 


Friday...brisk northerly flow expected. Leftover early morning 
showers will be possible across the Outer Cape and islands as the 
trough departs. Otherwise clearing is expected. Most of the region 
will experience high temperatures at least 5 degrees below normal. 


&& 


Long term /Friday night through Wednesday/... 
this portion of the forecast looks to be relatively tranquil with a 
modest East Coast middle level ridge through early next week. Models 
agree on the arrival of a middle level shortwave toward the middle of 
next week...but the cannot agree on its timing and amplitude. This is 
not uncommon for this time range. 


Building East Coast ridge should lead to a warming trend through 
early next week. A weak cool front is expected to cross southern New 
England early Sunday...but it is moisture-starved so it should not 
have much clouds or precipitation. Full sunshine should mitigate the 
shallow colder air it sends our way. This front is so weak...not 
expecting winds to shift northwest...which will also help to warm 
things up. 


Monday looks to be the warmest day of this period with south to 
southwest winds and plenty of sunshine. Tuesday could also be 
warm...but the uncertainty in the evolution of the middle level flow is 
resulting in significant timing issues for a cold front approaching 
our region. Currently thinking this front will arrive Tuesday 
night...so kept temperatures warmer on Tuesday but a bit below Monday 
in case there are more clouds. This front seems to be lacking 
abundant moisture as well...so just have some clouds int he forecast 
for now. 


&& 


Aviation /15z Thursday through Monday/... 
today and tonight...VFR ceilings and visibilities. Local MVFR possible in 
heavier precipitation. Scattered -shsn/-shra inland and -shra coast. 


Friday...VFR. North wind gusts to 25 knots. 


Outlook /Friday night through Monday/... 


Generally VFR. Patchy IFR in valley fog and stratus during the early 
morning hours each night. 


&& 


Marine... 
today...winds and seas expected to remain below Small Craft Advisory 
criteria. 


Tonight...a Small Craft Advisory has been posted across all of the 
waters. NE winds gusting to 20 to 30 knots as low pressure intensifies 
offshore allowing the pressure gradient to increase. Seas building 
to 4 to 6 feet late across the outer waters. 


Friday...a Small Craft Advisory continues for all of the waters. Seas 
building to 5 to 9 feet. North winds 20 to 30 knots. Scattered gale force wind 
gusts to 35 knots possible. 


Outlook /Friday night through Monday/... 


Small Craft Advisory may be needed Friday night into Saturday 
depending on how quickly seas subside from an offshore low pressure. 
Main area of concern would be the outer coastal waters east of Massachusetts. 
Could also see a brief period of wind gusts up to 25 knots Sunday 
morning as a weak cool front moves across the waters. 


&& 


Tides/coastal flooding... 
latest indications are the threat of coastal flooding is diminishing. 
Some splashover is possible during the Friday afternoon high tide. 
Some beach erosion is possible as well...especially across Cape Cod. 


&& 


Equipment... 
two of our National oceanic and atmospheric administration weather radio all hazards transmitters are down... 
Soapstone Connecticut /which covers NE CT and portions of SW Massachusetts/ and 
Camp Edwards Massachusetts /which covers portions of southeast Massachusetts including 
the cape and islands/. This appears to be a phone line problem and 
verizon has been notified. As of this time there is no estimated time 
for return to service. Look for additional updates in this product 
throughout the day. 


&& 


Box watches/warnings/advisories... 
CT...none. 
Massachusetts...none. 
New Hampshire...none. 
Rhode Island...none. 
Marine...Small Craft Advisory from 4 am to 7 PM EST Friday for 
anz230>237-250-251-254>256. 


&& 


$$ 
Synopsis...Belk/Strauss 
near term...Strauss/rlg 
short term...Strauss 
long term...Belk 
aviation...Belk/Strauss 
marine...Belk/Strauss 
tides/coastal flooding...Belk/Strauss 
equipment...rlg 

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