Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
1014 am EDT Thursday Jul 24 2014
high pressure will return to the region today through Saturday with
mainly dry weather and seasonably mild temperatures. Unsettled
conditions then return from Sunday Onward into the middle portions
of next week as upper level low pressure evolves across the Great
Lakes and transports moisture northward into the region.
Near term /until 6 PM this evening/...
as of 1013 am EDT Thursday...going forecast in good shape. Cold
air advection appears to be strong enough that temperatures will
struggle a bit...so have adjust maximum temperatures down a couple
of degrees. Otherwise...no other changes needed at this time.
Short term /6 PM this evening through Saturday/...
as of 345 am EDT Thursday...quiet/calm weather then continues
tonight with broad surface high pressure in control. Light winds
and generally clear skies should Foster ample radiative processes
with pleasantly cool lows in the 45 to 55 range expected. Patchy
dense fog also a good bet...especially in climatologically favored
By Friday another nice day on tap for the area as high pressure
remains in control for the most part with highs topping out from 75
to 82 under partly sunny skies. A weak shortwave and associated 850
dew point bubble will cross the area during the afternoon and may spark an
isolated shower or two across the higher terrain of the northern
mountains but the majority of the area...especially the broader
valleys will remain largely dry.
Then another partly cloudy/cl night on tap in the wake of the weak
shortwave Friday night. Patchy fog again a good bet here and there
with lows a tad milder under light southerly return flow...48 to 58.
By Saturday temperatures continue to gradually warm as surface high
slides offshore under gradually deepening south to southwesterly
flow. An approaching middle level shortwave from the Great Lakes will
likely begin to spread some clouds and a few showers into our far
western counties toward late afternoon or early evening but the
majority of the area will again remain dry as highs top out from 77
Long term /Saturday night through Wednesday/...
as of 345 am EDT Thursday...large-scale features remains generally
well specified amongst 00z/25th guidance suite. An initial period
of quasi-zonal...broadly cyclonic flow opens the period. This
transitions to an amplified Continental U.S. 500-mb pattern resembling a
+pna: a retrograding middle-level low parked across the Great Lakes
and a large ridge over the western Continental U.S.. that Great Lakes low
likely to stick around for some time (at least into midweek)
resulting in several opportunities for clouds/precipitation. Still
some timing differences between 00z GFS/European model (ecmwf) in initial shortwave
trough energy rounding the Great Lakes low with the European model (ecmwf) a tad
Though unsettled conditions will predominate the period...Sunday
would be one day that will bear watching going forward. Fairly
strong shortwave trough looks to cross the Great Lakes Sunday/Sunday
night. Sunday afternoon offers the best overlay of dynamic support
with prognosticated air mass characteristics over the north country
conducive to strong convection (1000-1500 j/kg cape...-4 to
-6 lifted indices...and a fast belt of middle-level westerlies
producing 30-35kt 0-6 km shear magnitudes). Otherwise...the rest of
the period features high chance to low-likely probability of precipitation gradually
tapering lower each successive day.
Temperatures in the extended start off near normal for late July
(highs in the lower 80s...lows in the 50s/low 60s) turning slightly
cooler than normal into midweek.
Aviation /14z Thursday through Monday/...
through 12z Friday...clearing has been slow to occur at rut early
this morning where ceilings have stayed generally MVFR (ifr at
times). That will continue through middle-morning before trending
VFR. Broken/overcast VFR for rest of the tafs early this morning but cloud
coverage will lessen through the morning hours. Model soundings
showing dry conditions through a deep depth suggest only a few
fair weather cumulus with relatively high bases (6 kft). Mist/fog with
potential IFR/lower visibilities appears a good bet at slk and mpv
under strong radiational cooling. North winds 6-10 knots become
light/variable by early evening.
Outlook 12z Friday through Monday...
12z Friday - 00z Sat...VFR. Can't rule out an afternoon isolated shower
affecting higher terrain (primarily mpv and slk) though not
expecting visibility restrictions.
00z Sat - 12z Sat...VFR with potential IFR/lower visibility at mpv
and slk with fog/mist.
12z Sat - 12z sun...VFR under high pressure.
12z sun Onward...trending increasingly unsettled. Though mostly
VFR...periodic showers/storms with possible brief MVFR/IFR