053 
fxus61 kbtv 201718 
afdbtv 


Area forecast discussion 
National Weather Service Burlington Vermont 
118 PM EDT Sat Mar 20 2010 


Synopsis... 
unseasonably warm temperatures persist in the north country for 
at least the first half of today. A cold front will pass through 
the region from the north...bringing clouds and cooler 
temperatures this afternoon. The front will remain in the region 
tomorrow increasing potential for rain showers. A low pressure 
system will move northeast from the Ohio Valley...bringing rain for 
the start of the work week. 


&& 


Near term /until 6 PM this evening/... 
as of 1139 am EDT Saturday...going forecast in good shape late 
this morning. Updated products sent out with just a few minor 
adjustments to temperatures. Cold front moving through St Lower Valley at this time with 
clouds but very little precipitation being reported or detected on radar. A 
few sprinkles have been reported...so have continued a mention for 
all northern zones this PM. Temperatures vary greatly across the area...ranging 
from around around 60 in portions of central/southern Vermont 
where sunshine still occurring...to the lower 40s north of the 
cold front. Adjusted temperatures to reflect current conditions...and raised 
them a bit for this PM in those areas that will see the most sun 
(srn/eastern vt). No other changes at this time. 


Previous discussion... 
temperatures vary across the region this morning with Springfield 
and the Northeast Kingdom below freezing...the Champlain Valley 
generally near 50... and the St. Lawrence Valley in the middle to 
lower 40s. This large swing is due to varying cloud cover. To the 
north a sharp cold front is draped across Ontario and western 
Quebec. Earlier this morning a 43 degree temperature range was 
noted within a 350 mile distance on either side of the front in 
Quebec. A dramatic change that is trying to push through our area. 
The front will pass through the St Lawrence Valley and northern 
Adirondacks this morning...then push through the remainder of the 
forecast area this afternoon. Ahead of the front...areas generally 
from the Champlain Valley east will see temperatures warm to well 
above seasonal levels. Then temperatures will drop rapidly. 
Upstream observations show a few light showers with and behind the 
front. Best potential for a light shower will be in the Saint 
Lawrence valley and Adirondacks... but most likely we should only 
see sprinkles. With and behind the front winds will increase a bit 
from the northwest... but any gusts should be limited to the 20-25 miles per hour 
range. 


&& 


Short term /6 PM this evening through Monday night/... 
as of 510 am EDT Saturday...through Monday the weather will be 
dominated by front mentioned above...as it oscillates north and 
south across the region. The front will remain nearly stationary 
just south of our area tonight. Again...a few light scatted showers 
are possible. And with cooling temperatures these will likely be 
in the form of flurries. The front will then lift north Sunday 
afternoon...revisiting the area... if you will...but this time as 
a warm front. Guidance suggests some frontogenesis with this 
feature...and with some good vertical motion right over the north 
country middle and late day. Combined with a flow that becomes 
more south-southwest vs westerly...it will provide US our best chance 
of rain. Again...this is middle and late day Sunday. Sunday night 
the front then drops south again as a cold front...maintaining 
showers especially in southeast portion of the forecast area...but with 
drying and cooling conditions in the northwest. Monday morning temperatures will 
range from the middle 20s in the St. Lawrence Valley and 
Adirondacks... to the lower 40s in the southern Champlain Valley. 
As such...some showers overnight and early in the morning could 
be mixed with snow in northern New York and extreme northern 
Vermont. Then Monday...the front will return north as a warm 
front in advance of a large system moving northeast from the Ohio 
Valley. This will once again bring a potential for 
rain...especially in southern areas. As mentioned above...we will 
see some temperature variations as the front moves back and forth 
over this period...but generally speaking temperates should run a 
few degrees above seasonal levels. 


&& 


Long term /Tuesday through Friday/... 
as of 346 am EDT Saturday... 


Confidence low for northern extent of precipitation Tuesday and Wednesday 
and timing of weather features Thursday and Friday. 


Confidence fair that temperatures will be around seasonal 
averages... with a cooling trend...especially later in the week. 


One thing that looks pretty clear is that our record breaking 
warm late winter weather is a thing of the past. 


Frontal system across the northeast US will be focus for 
precipitation and should provide a path for low pressure moving 
from the the middle Atlantic Monday night and south of New England 
Tuesday night and out to sea on Wednesday. 


Our area appears to be on the northern fringe of the 
precipitation which causes problems for determining 
precipitation amounts and type. 


Higher probabilities of precipitation at this time look to be 
across central and southern New England and New York on Tuesday then 
shift to northern areas for the rest of the week. 


Basically have let near surface temperatures govern precipitation 
type of rain or snow with higher probabilities of snow to the 
north...in higher terrain...and at night. 


Models continue to show colder air moving southeast from central 
Canada Thursday and Friday. The airmass should be modified as it moves 
south. There is considerable disagreement on timing of the 
associated front or fronts and how cold it will be. There could 
be several fronts or troughs that move through Wednesday night through 
Friday with chances of snow or rain showers. 


&& 


Aviation /17z Saturday through Wednesday/... 
through 18z Sunday...surface cold front continues to sink southward 
across the area as of 17z as winds veer from SW to northwest from 6 to 10 
knots and skies trend from sky clear to broken/overcast mainly VFR ceilings from 
040-070 kft. A few Post-frontal sprinkles also streaking east 
across southern Canada into northern New York per current radar analysis and will 
include mention at northern New York terminals accordingly along with patchy 
MVFR ceilings. Otw expect light northwesterly and/or northeasterly 
flow and mainly broken/overcast VFR ceilings from 050-080 kft into the 
evening/overnight hours. Area should mainly be precipitation free. After 
12z Sunday front essentially washes out across central New England 
as flow becomes very light. Broken/overcast VFR ceilings likely to persist 
however. 


Outlook 18z Sunday through Wednesday...mainly VFR...chance of 
MVFR in -ra/snow later Sunday afternoon through Wednesday. Low pressure 
will move very slowly along a stationary front in southern New 
England. Confidence is low in location and timing of the front and 
low. 


&& 


Climate... 
three daily maximum temperature records were broken on Friday. 
These included btv /66f/...mpv /64f/...and mss /61f/. The old 
records were 60f...57f...and 60f...respectively. For further 
details...please see our record event statement. 


&& 


Btv watches/warnings/advisories... 
Vermont...none. 
New York...none. 


&& 


$$ 
Synopsis...amf 
near term...amf/rjs 
short term...amf 
long term...Sisson 
aviation...jmg/Sisson 
climate...weather forecast office btv 

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