496 
fxus61 kbtv 180743 
afdbtv 


Area forecast discussion 
National Weather Service Burlington Vermont 
343 am EDT Thursday Mar 18 2010 


Synopsis... 
a weak back door cold front will push into the region from the 
north today...with nothing more than an increase in cloud cover 
and slightly cooler temperatures from yesterday. The next chance 
for precipitation will come Sunday evening and into the beginning 
of next week...as low pressure moves out of the Ohio River valley 
and up through the northeast. 


&& 


Near term /until 6 PM this evening/... 
as of 343 am EDT Thursday...a weak back door cold front will be 
moving south through Quebec and across the north country today. 
With the lack of any real surface moisture just expecting an 
increase in cloud cover...but no precipitation. While the cloud 
cover should inhibit full mixing...temperatures will still remain 
on the warm side with most areas warming into the 50s again. 


&& 


Short term /6 PM this evening through Saturday/... 
as of 343 am EDT Thursday...more of the same tonight into Friday 
as a weak system will be moving eastward across Ontario and 
Quebec...though will be far enough north that conditions will 
remain dry over the north country. Back door front which will 
have moved across the area during the day will be moving back 
northward as a warm front during Friday...bringing temperatures back 
into the upper 50s and lowers 60s. This will be near record highs 
for some locations with records possibly being broken at btv 
(60/1894)... mpv (57/1968) and mss (60/1986). Sunny and dry 
conditions continue into Saturday with even warmer temperatures 
expected...though highs will not be near records except for mpv 
which will be close. 


&& 


Long term /Saturday night through Wednesday/... 
as of 320 PM EDT Wednesday...overall confidence for the period is moderate... 
although low on exact timing of strong cold front passage Sunday 
night. 


Potential for significant weather impacts...moderate. 


Long term forecast period starts off rather quiet...but continued 
extremely warm. Warm air and ridging will be in place...so it 
looks like the first day of Spring will be more like early may. 
Guidance suggesting easily low 60s area wide...but given current 
trend with guidance being a bit too cool...have nudged up 
some...so suspect middle 60s quite possible in valleys. If GFS is to 
be believed with 850mb temperatures approaching 5c...perhaps a few spots 
may touch 70f. 


Bigger differences now between GFS and European model (ecmwf) than compared to 
24hrs ago. GFS has sped up the timing of low pressure and 
associated strong cold front across the region. It shows frontal 
passage Sunday evening...while the European model (ecmwf) is holding off things 
until Monday. Have compromised between the guidance solutions... 
which is in line with previous forecasts. 


Sunday still looking to be another warm day...although exactly how 
warm will depend upon how much clouds/showers we are dealing with. 
GFS would say highs only in the 50s...slower European model (ecmwf) says another 
day well into the 60s. Split the difference...so upper 50s-lower 
60s should be common place. 


Given strength of cold front...suspect temperatures could drop 10f in 2 hours 
with its passage....a small timing error will lead to big 
temperature forecast busts Sunday night and Monday...so take those 
forecasts with a bit of a grain of salt. 


Guidance still showing strong low level southerly jet developing 
Sunday/Sunday night. Could make for some gusty winds...especially 
in Champlain and St Lawrence valleys. Still think we may be close 
to Wind Advisory conditions. 


Other issue will be the amount of precipitation. Pretty high precipitable 
waters will be tapped and brought into the system. Good news is 
that it looks like it moves through pretty quickly...so amounts 
will be limited. Think 0.50-1.00 inch of precipitation is possible. 
Recent snow survey across the region indicate that we dont have a 
lot of snow left...and more will be gone prior to the rainfall. 
Thus although we will see river rises...dont think flooding will 
be an issue. Later forecasts will fine tune that prediction. 


Winter returns for Monday and Tuesday...850mb temperatures down to 
-10 to -13c...which supports highs only in the 30s at lower 
elevations (20s up higher). A brisk northwest wind will make it 
feel colder. Residual moisture will lead to scattered snow 
showers...primarily in the higher terrain...with perhaps some minor 
accumulations. 


Model guidance now showing that the shot of cold air will be 
shorter lasting with normal temperatures for Wednesday. Lots of 
uncertainty this far out...so I stuck to guidance for Wednesday. 


&& 


Aviation /08z Thursday through Monday/... 
through 06z Friday...VFR conditions will persist through the 
forecast period. Some minor low level wind shear at kbtv and kpbg tonight with 
light and variable surface winds yet westerly 25kt at 2kft. This will 
diminish as winds increase with daylight mixing. A front is 
approaching from the north-northwest which will cause some minor wind shifts 
today. Mainly winds will be west to northwest...and 8-12kt in the 
afternoon period...before diminishing to less than 6kt after 
sunset. Clouds will be more numerous in the northern mountains...but 
generally no lower than 9kft. No precipitation is expected. 


Outlook 06z Friday through Monday... 
00z Friday-00z sun...VFR. 
00z sun-00z Monday...mainly VFR...though occasional MVFR in -shra. Increasingly 
gusty surface winds. 
00z Monday-00z Tuesday...MVFR with local IFR with rain showers. Gusty surface winds. 


&& 


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


&& 


$$ 
Synopsis...lahiff 
near term...lahiff 
short term...lahiff 
long term...Nash 
aviation...amf