powderfreak
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- Jan 9, 2007
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Well, its finally about that time again. After this cold front and
anafrontal rain clears the area this afternoon, a crisp high pressure system
will build over the region tonight...and linger through Thursday. This will
lead to cool days on Wed/Thurs with a cool night tonight, and a frosty on on
Wednesday night in areas away from the moderating effect of Lake Champlain
(68F water temp).
850mb temperatures look to fall to 0C-3C tonight and remain there for about
36 hours before moderating on Wednesday to 4C-6C. The GFS is slightly
warmer than the NAM at that level. While I prefer the GFS's warmer values,
should the NAM's -1C verify late tonight there could be some rime by morning
across the 4K foot mark as partial cloudiness should persist over the spine
tonight thanks to strong cold air advection.
At the very least, these cold H85 temps (good indicator of summit level
temps along the 4K peaks) will mean the high peaks in the 'Dacks and Vermont
(Ellen, the Hump, Manni, Jay) might not get out of the upper 30s for highs
on Wednesday! 1,500ft highs will be chilly in the low/mid 50s with near 60
or low 60s in the immediate CPV. It certainly will feel like a fall day in
the mountains with 50s at the base and 30s at the summits.
Then on Wednesday night as the high pressure is cresting over our area,
temps should plummet in the mountain valleys. Cold air drainage down the
mountains into the valleys will allow for a strong inversion to set up, so
the summits will remain in the upper 30s while the valleys drop to 30-35F.
GFS MOS guidance has BTV at 37F, Morrisville/MVL at 34F, and Montpelier/MPV
at 38F on Wednesday morning. The limiting factor for really cold temps will
be fog formation in the larger valleys...and the GFS is developing thick fog
over MPV and the Winooski River Valley by 3am Wed, resulting in a higher
guidance temp.
I'm forecasting generally 30-35F over most of central/northern Vermont away
from the moderating influence of Lake Champlain (mainly spine and eastward)
except where dense fog forms...in areas of dense fog lows should hold in the
middle 30s. Fog formation will be the main limiting factor for a
widespread frost. The greater Champlain Valley will likely bottom out near
40F with 45-50F along the immediate lake front (my current location).
C'mon old man Winter! Junkboard season is just around the corner, and frost
skiing is even closer
-Scott
From the Burlington NWS this morning:
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
AS OF 255 AM EDT TUESDAY...MAIN FEATURE DURING THIS TIME PERIOD IS
THE BUILDING OF SURFACE HIGH PRESSURE AND DRY AIR OVER THE REGION.
THIS WILL GIVE US QUITE A BIT OF SUN ON WEDNESDAY AND THURSDAY.
SURFACE HIGH CENTERED RIGHT OVER THE TOP OF US WEDNESDAY
NIGHT...AND CLEAR SKIES AND NO WIND ALLOWING FOR GOOD RADIATIONAL
COOLING POTENTIAL. PROMISES TO BE COOLEST OF THE SEASON SO FAR IN
MANY SPOTS. WILL BE WIDE VARIABILITY IN OVERNIGHT LOWS WEDNESDAY
NIGHT...WITH VALLEYS...HOLLOWS AND OTHER LOW SPOTS POOLING THE
COLDEST AIR...AND MOUNTAIN SIDES AND MOUNTAIN TOPS ABOVE THE
INVERSION BEING WARMER. FIRST FREEZING TEMPS AND/OR FROST OF THE
SEASON A POSSIBILITY OUTSIDE THE LAKE CHAMPLAIN VALLEY.
anafrontal rain clears the area this afternoon, a crisp high pressure system
will build over the region tonight...and linger through Thursday. This will
lead to cool days on Wed/Thurs with a cool night tonight, and a frosty on on
Wednesday night in areas away from the moderating effect of Lake Champlain
(68F water temp).
850mb temperatures look to fall to 0C-3C tonight and remain there for about
36 hours before moderating on Wednesday to 4C-6C. The GFS is slightly
warmer than the NAM at that level. While I prefer the GFS's warmer values,
should the NAM's -1C verify late tonight there could be some rime by morning
across the 4K foot mark as partial cloudiness should persist over the spine
tonight thanks to strong cold air advection.
At the very least, these cold H85 temps (good indicator of summit level
temps along the 4K peaks) will mean the high peaks in the 'Dacks and Vermont
(Ellen, the Hump, Manni, Jay) might not get out of the upper 30s for highs
on Wednesday! 1,500ft highs will be chilly in the low/mid 50s with near 60
or low 60s in the immediate CPV. It certainly will feel like a fall day in
the mountains with 50s at the base and 30s at the summits.
Then on Wednesday night as the high pressure is cresting over our area,
temps should plummet in the mountain valleys. Cold air drainage down the
mountains into the valleys will allow for a strong inversion to set up, so
the summits will remain in the upper 30s while the valleys drop to 30-35F.
GFS MOS guidance has BTV at 37F, Morrisville/MVL at 34F, and Montpelier/MPV
at 38F on Wednesday morning. The limiting factor for really cold temps will
be fog formation in the larger valleys...and the GFS is developing thick fog
over MPV and the Winooski River Valley by 3am Wed, resulting in a higher
guidance temp.
I'm forecasting generally 30-35F over most of central/northern Vermont away
from the moderating influence of Lake Champlain (mainly spine and eastward)
except where dense fog forms...in areas of dense fog lows should hold in the
middle 30s. Fog formation will be the main limiting factor for a
widespread frost. The greater Champlain Valley will likely bottom out near
40F with 45-50F along the immediate lake front (my current location).
C'mon old man Winter! Junkboard season is just around the corner, and frost
skiing is even closer
-Scott
From the Burlington NWS this morning:
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
AS OF 255 AM EDT TUESDAY...MAIN FEATURE DURING THIS TIME PERIOD IS
THE BUILDING OF SURFACE HIGH PRESSURE AND DRY AIR OVER THE REGION.
THIS WILL GIVE US QUITE A BIT OF SUN ON WEDNESDAY AND THURSDAY.
SURFACE HIGH CENTERED RIGHT OVER THE TOP OF US WEDNESDAY
NIGHT...AND CLEAR SKIES AND NO WIND ALLOWING FOR GOOD RADIATIONAL
COOLING POTENTIAL. PROMISES TO BE COOLEST OF THE SEASON SO FAR IN
MANY SPOTS. WILL BE WIDE VARIABILITY IN OVERNIGHT LOWS WEDNESDAY
NIGHT...WITH VALLEYS...HOLLOWS AND OTHER LOW SPOTS POOLING THE
COLDEST AIR...AND MOUNTAIN SIDES AND MOUNTAIN TOPS ABOVE THE
INVERSION BEING WARMER. FIRST FREEZING TEMPS AND/OR FROST OF THE
SEASON A POSSIBILITY OUTSIDE THE LAKE CHAMPLAIN VALLEY.
