864 
fxus61 kbtv 070538 
afdbtv 


Area forecast discussion 
National Weather Service Burlington Vermont 
138 am EDT Tuesday Oct 7 2008 


Synopsis... 
a cold upper level trough will shift southeast off the New England 
coast tonight resulting in diminishing cloud cover across the 
north country this evening. A strong area of high pressure will 
build in behind this system...from north of Lake Huron to 
southeast Ontario into central New York state by early Tuesday 
morning. This will result in ideal radiational cooling conditions 
tonight with much of the north country at or below freezing for 
early morning lows on Tuesday...with areas of frost expected. 
The region of high pressure will bring fair weather conditions 
through Wednesday. 


&& 


Near term /until 6 am this morning/... 
as of 946 PM EDT Monday...quick and very minor update to this 
evening/S package...mainly to reflect latest trends in T/TD/sky 
cover across the region. Expansive and elongated 1032 hpa surface high 
pressure extending from western New York northward into SC Canada will 
provide generally clear skies and light winds overnight. With deep 
synoptic inversion and dry air in place...optimal raditional cooling 
and frosty conds expected in most areas by the pre-dawn hours. Only 
exception will be areas near Lake Champlain shoreline where some 
moderating effect of 60f water temperatures will occur. Some patchy fog 
again possbl...especially in favored areas. Other than minor adjustments 
noted above...inherited package in excellent shape and no other 
changes needed. Enjoy the evening. 


&& 


Short term /6 am this morning through Wednesday night/... 
as of 350 PM EDT Monday...a deep-tropospheric ridge axis in place 
across the north country will bring a tranquil stretch of weather 
Tuesday through early Wednesday night...with no precipitation 
expected. Another cold night is expected Tuesday night...with low 
temperatures in a similar range to those expected tonight /most of 
the forecast area will see min temperatures at or below 32f/. Skies will 
be mostly clear through much of the period...except for increasing 
clouds from west to east during Wednesday night. A weakening 
frontal system approaches late Wednesday night and have included a 
chance of showers for this feature. At this point...most 
precipitation amounts through 12z Thursday should be at or below a tenth 
of an inch. 


&& 


Long term /Thursday through Monday/... 
as of 300 PM EDT Monday...above normal temperatures to affect the 
area from Thursday through Sunday. Warm air advection will stream into the area 
ahead of approaching weak cold front on Thursday. Limited 
moisture with this feature...and best dynamics will remain well 
to our north...so have only included chance for showers during 
Thursday. A surface ridge will build in behind the front on 
Friday...and another low pressure system will form over the 
Carolinas. Formation of this low has actually been pretty 
persistent in the GFS model runs over the past two days. There is 
a possibility for the moisture associated with this low to get 
caught up in the flow and stream across the northeast for 
Saturday through Sunday. At this time have just included chance 
probability of precipitation because of a lack of model to model consistency. Hopefully 
soon the models will come together a bit more for days 4 through 
8 because the last few days have been low confidence 
forecasts...as is today. Another low pressure system will pass 
well to our north on Sunday...bringing weak cold front across the 
region. Have again mentioned very low chance probability of precipitation. 


&& 


Aviation /06z Tuesday through Saturday/... 
through 06z Wednesday...VFR clear forecast through the first 24 
hours. Removed mention of fog during the overnight hours. Very 
low dewpoints keeping fog at Bay despite clear skies/light winds 
for good radiational cooling. Kcxx VAD winds showing 20kts north 
wind right off the surface...and despite very shallow surface 
inversion this north wind will continue to advect drier air into the 
region to inhibit fog formation. Will keep forecast optimistic 
VFR clear for remainder of night...but monitor closely and amend if 
fog formation does occur. A clear day on tap as ridge axis moves 
east...and is centered over region 00-06z Wednesday timeframe. 


06z Wednesday through Saturday...VFR to continue through 
Wednesday night as high pressure at the surface and aloft remain 
the dominant feature across the north country. Some light return 
flow may set up 06-12z Wednesday...so potential for IFR ceilings/visible early 
Wednesday morning at the usual sites due to fog. A weakening cold 
front will slip across the forecast area Thursday bringing the 
chance for light rain showers to all taf sites. Given the lack of 
moisture with this system...conditions should remain VFR/MVFR. 
High pressure and fair weather and VFR conds will return by Friday 
morning. Latest model guidance backing off rain potential on 
Saturday with high pressure remaining over the north country. 


Notice to users of terminal Aerodrome forecasts (taf)...beginning 
at 0000 UTC on November 5...2008...the format for tafs will 
change. The National Weather Service will begin to issue tafs 
using a valid date and time group in the forecast. All 
meteorological agencies worldwide will also issue their taf 
forecasts in this new format. This is being done to accommodate 
30 hour taf forecasts that will be done for select major 
international airports worldwide. There will be 32 major U.S. 
International airports for which tafs forecasts will be valid for 
30 hours. This format change is being mandated by the 
international civil aviation organization (icao). The 6 taf 
forecasts being done by the National Weather Service in 
Burlington will continue to be valid for 24 hours. To see 
examples of this new format...please go to the internet web site 
listed below. 


Www.Aviationweather.Gov/notice/taf30.Php (all lower case) 


&& 


Btv watches/warnings/advisories... 
Vermont...freeze warning until 8 am EDT this morning for vtz003-006-008- 
010-012-016>019. 
Frost advisory until 8 am EDT this morning for vtz001-002-005- 
009-011. 
New York...freeze warning until 8 am EDT this morning for nyz026-027-087. 
Frost advisory until 8 am EDT this morning for nyz028-035. 


&& 


$$ 
Synopsis...banacos 
near term...banacos/jmg 
short term...banacos 
long term...neiles 
aviation...Hanson 

National Weather Service Glossary of Abbreviations

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