Area forecast discussion
National Weather Service Gray ME
639 am EDT Thursday Jun 20 2013
Synopsis...
high pressure will build east across the region through Thursday,
then slide offshore Friday...and sit over the western Atlantic
into early next week. This will allow southwest flow to develop
across New England...transporting warmer and more humid air into
the region Sunday into early next week. Along with this warmer and
more humid air mass will come a chance for showers and
thunderstorms.
&&
Near term /until 6 PM this evening/...
635 am...no real changes to forecast...just some minor tweaks
based on current observation. Fog in the valleys should diminish 12-13z.
Otherwise a mainly sunny answer seasonably warm day is in store.
Previously...surface ridging will remain over the northestern Continental U.S.
Today...this will allow for another sunny day...once any fog Burns
off early. Temperatures will be a few degrees warmer than Wednesday away
from the coast...mainly in the middle 70s north...to around 80 S. With
the high centered over the area...low to middle level flow remains
light...and sea breeze will develop earlier today...keeping
coastal highs in the low to middle 70s.
&&
Short term /6 PM this evening through 6 PM Friday/...
the high shifts offshore tonight...and will likely see some SW flow
develop on the bl...which will prevent strong rad cooling in all
but the sheltered areas. Mins will still be on the cooler
side...but several degrees warmer than this morning. Cirrus
spilling in from the west will also limit the rad cooling.
On Friday...a 500 mb wave will track southeast out of northern Quebec toward the
Maritimes. This wave will generally stay north and east of New Hampshire and
ME...but will attempt to drag a surface cold front into northern ME. The
front will lose its punch and forward momentum...so will not have
any effect on temperatures...but could set off a few rain showers/thunderstorms and rain especially
in northestern zones. Highs in southern zones will once again be noticeable
warmer...reaching into the low to middle 80s...and generally 75 to 80
elsewhere. Should see enough of a SW flow to prevent a true sea
breeze...but winds will be onshore along the mid-coast...keeping
it cooler...and will turn onshore from Casco Bay S...shaving a few
degrees off the maxes there.
&&
Long term /Friday night through Wednesday/...
not much change to the overall long term forecast. Both European model (ecmwf) and
GFS ensembles build heights through the extended....gradually
bringing warmer temperatures into the area by next week. Highest heights
and largest temperature departures wait until early next week to push
into New England...so the weekend will be more of a transition
period. As baroclinic zone lifts through the area...one or more shortwave
troughs may try and top the ridge and bring a threat for rain showers or
thunderstorms. Rain showers and thunderstorms look more likely next week...as upper low
ejects out of the High Plains and flow becomes more zonal across
the northeast. Timing of individual shortwave troughs will be key...as
passage during favorable diurnal maximum in heating would likely yield
a few stronger storms. Through the weekend...steep low level lapse rates
could bring some gusty winds with any rain showers/thunderstorms that do form.
However...steep lapse rates aloft will wait until early next week
to ripple through the flow and make their way east. Again if any midweek
frontal passage can remain timed to cross the area in the afternoon...this
could lead to stronger storms. Given the propensity for nwp to
struggle to capture this timing correctly...have stuck close to
previous pop forecast with a blend of the latest HPC/wpc. Temperatures
are a blend of the previous forecast with an even blend of the
mex/European model (ecmwf) MOS/wpc...with temperatures beginning near normal and trending
to above by early next week.
&&
Aviation /12z Thursday through Monday/...
short term...635 am...fog and stratus was late to move into
khie/kleb...but did creep in just after sunrise. It should break
up by 12z or so. Otherwise expect VFR.
Long term...VFR conds to prevail in the extended. Periods of MVFR
or lower will be possible in any rain showers/thunderstorm activity through early next
week. In addition...as air mass becomes more humid with
time...nighttime valley fog will become more widespread.
&&
Marine...
short term...waters will be generally quiet through Friday. Will
see an surge of SW winds Friday as a cold front drops into northern
ME...but gusts should be limited to around 20 knots.
Long term / Friday through Monday night/...winds to stay below
Small Craft Advisory levels. Seas will build with time as a SW flow develops.
&&
Gyx watches/warnings/advisories...
ME...none.
New Hampshire...none.
Marine...none.
&&
$$
Synopsis...
near term...cempa
short term...
long term...
aviation...
marine...
