Area forecast discussion...updated
National Weather Service Gray ME
709 am EDT Thursday may 23 2013
Synopsis...
a warm front will move north across the area today as low pressure
tracks along the New England Canadian border. A cold front moves
through from west to east late today into Friday. Low pressure
redevelops offshore for the weekend before slowly moving towards
the Canadian Maritimes. Weak high pressure builds in Monday
through Wednesday.
&&
Near term /until 6 PM this evening/...
update...
most of the area is rain free with just a little drizzle along
the coast. Patchy dense fog has developed...also along the coast.
Precipitation chances as well as temperatures and dew points were
adjusted to match current trends.
&&
Previous discussion...
shower activity which moved through earlier has exited the
forecast area. A line of convection in Vermont has been weakening
steadily as it moves into New Hampshire and a more stable airmass. After
this activity dissipates this morning there will be a break in
precipitation until this afternoon when a warm front lifts north
across the area. The front is now located from Vermont into
Massachusetts. As the front shifts north warmer air will
infiltrate southern New Hampshire and southwest Maine. Highs in this area
will warm into the middle 70s with upper 60s to the north and east of
the boundary.
Low level jet increases to 40-50 kts later this afternoon ahead of an
approaching cold front. This along with increased forcing for
ascent will increase thunderstorm chances across the area. Severe
weather in the form of damaging winds is a slight possibility as
per Storm Prediction Center...especially over western New Hampshire this afternoon. The main
challenge for severe weather development will be dense cloud
cover. That said...only a few breaks in the clouds are needed to
boost instability.
&&
Short term /6 PM this evening through 6 PM Friday/...
a sharp upper trough will push the north-northeast-south-southwest oriented cold front
through the region late tonight into Friday morning...triggering
widespread showers and thunderstorms. Isentropic lift looks good
with the 40-50 knots jet in place.
Precipitable water values jump to near 1.8 inches. A Flood Watch was decided
against as rainfall has not been as high here as it has been to
our west. However...the higher terrain may approach flash flood
guidance in a few basins by tomorrow afternoon. Tonight's lows and
friday's highs only differ by a few degrees.
&&
Long term /Friday night through Wednesday/...
as the upper level low pressure system continues to migrate
eastward and moves over the Middle Atlantic States...the attendant
surface low south of Cape Cod will start to slow down. Northeast
flow and wrap around moisture will keep precipitation in place
over the County Warning Area on Saturday. The system becomes pretty much stacked
over the benchmark by 00z Sunday with little in the way of a break
from the precipitation over northern New England. The low will
track across the Gulf of Maine before entering the Canadian
Maritimes on Monday. Weak high pressure then builds over the
region for the remainder of the forecast period.
Seemingly...the models have slowed down the progression of this
system with just about every run so clearing the Gulf of Maine on
Monday might be a bit optimistic. We will have to watch the next
few runs to see if the system looks like it will slow even more
than it already has.
&&
Aviation /12z Thursday through Monday/...
short term...LIFR/IFR conditions this morning with visibilities
and ceilings improving by late morning. Gusty south winds will
develop as a warm front lifts north. Showers and thunderstorms
will develop later this afternoon and evening keeping conditions
low. Visibilities and ceilings will drop further tonight.
Long term...
LIFR/IFR conditions will prevail for most of the long term as a
slow moving low pressure system moves across the region.
&&
Marine...
short term...Small Craft Advisory was extended through Saturday
morning with winds and waves staying above criteria.
Long term...as low pressure develops and moves across the Gulf of
Maine...expect Small Craft Advisory for most of the weekend.
Persistent easterly flow will help keep seas above Small Craft Advisory criteria.
&&
Fire weather...
fire weather concerns remain low with recent rains keeping fuels
moist. Rain is expected areawide through the weekend.
&&
Gyx watches/warnings/advisories...
ME...none.
New Hampshire...none.
Marine...Small Craft Advisory from noon today to 8 am EDT Saturday for
anz150>154.
&&
$$
Hanes/pohl
