Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Gray ME
726 am EDT Friday Jul 25 2014
high pressure will build in from the west today and then move
offshore...staying to our south tonight and Saturday. A trough of
low pressure will bring wet weather Sunday and Monday.
Near term /through tonight/...
update...minor adjustments to account for current observational
Previous discussion...high pressure will continue to build in from
the west...then slide S through today. The result will be flow becoming
more southerly...and warming temperatures. Should reach the lower 80s today for
much of the interior...with southerly flow/sea breeze keeping the coast
cooler. Channeled vorticity around the Quebec upper low will also
be directed towards northern zones this afternoon. Cannot rule out an
isolated rain showers in the mountains as a result.
Short term /Saturday through Saturday night/...
SW flow will keep temperatures a few degrees warmer than we/re seeing
this morning. However...conditions will still favor some patchy
valley fog. Atmosphere will grow increasingly unstable ahead of
developing eastern trough...so rain showers will likely be a little more
numerous Sat afternoon over the high terrain...but still of the
scattered variety. Expect temperatures to be a couple degrees warmer than
Long term /Sunday through Thursday/...
a series of shortwave troughs will cross the region Saturday
night through Tuesday...exact timing of each one varies slightly
from model to model. Over all an unsettled periods expected
beginning Sat night with the first in the series to affect the
area. Indices indicate thunderstorms can be expected Sat night into Sunday
morning. If timing is right, then a brief break will occur sometime
late Sunday but another round of showers/thunderstorms expected again Monday
into Monday night as a more pronounced l/WV trough surface/upper trough slowly
moves through New England. On Tuesday some lingering scattered showers expected
as the trough only slowly exits the region and enough cyclonic flow
to allow instblty showers to develop. Temperatures will be mild but due to
clouds/showers limited diurnal heating will keep temperatures in the upper
70s to lower 80s during the day. Nights will be mild with lows in
By midweek clearing takes place with a drier Canadian air mass with drier
and pleasant temperatures. Stayed very close to the superblend input for
probability of precipitation and temperatures. Used a blend of HPC and model guidance for quantitative precipitation forecast.
Aviation /12z Friday through Tuesday/...
short term /through Friday night/...patchy valley fog will
continue this morning...with highly vrb ceilings and visibilities. Expect
widespread VFR conditions today. More valley fog is possible again
tonight...with local IFR or lower conditions. Late in the day Sat
rain showers or a thunderstorm moving in from the west could bring some MVFR
conditions to parts of New Hampshire.
Long term...scattered convection Sat night through Tuesday lowering
ceilings/visibilities to MVFR/IFR at times. Conds improved to VFR midweek.
short term /tonight through Friday night/...high pressure builds over
the waters today and holds through Sat. Winds and seas will remain
below Small Craft Advisory thresholds. Undercut wna and Swan guidance for seas
Sat...as they appear to bring wave heights up to and over 5 feet too
quickly in SW flow regime.
Long term...southerly flow increases on Sunday but should remain
below 25 knots. Models bring wave heights up to 5 feet or above over
the outer waters on the S flow...thus may need a Small Craft Advisory for late Sat
night and Sunday.