Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
328 am EDT Sat Jul 30 2016
cooler and drier Canadian high pressure will build across the area
through today. The next disturbance approaches from the west Sunday
and early next week bringing rain to the region. Mainly dry weather
with a gradual warming trend is expected beginning Wednesday through
late next week.
Near term /through today/...
at 06z...a 1020 millibar high was centered north of Lake Huron.
GOES infrared imagery showed mainly clear skies across the forecast
area under the building high. There was a band of marine stratus
and fog to our east over the Gulf of Maine that was reaching the
coastline vicinity of Penobscot Bay. Across the interior...the
light winds and clear skies were allowing some patchy valley
stratus and fog to develop. For today...the surface high will
continue to nose into the area from the north. We'll see a mostly
sunny day with comfortable humidity levels. Highs will range from
the 70s across the mountains to the lower and mid 80s elsewhere.
The light synoptic flow will turn onshore by afternoon in a
Short term /tonight through 6 PM Sunday/...
clouds will spread north and east into southern New Hampshire and
extreme southwest Maine overnight...as the high retreats into the
Maritimes and in advance of the next disturbance approaching from
the Midwest. The European model (ecmwf) continues to be the most bullish with the
northern extent of the precipitation shield...and while still an
outlier has begun to trend closer to the NAM...CMC-global...and
GFS solutions. Accordingly...I confined pops to the southern third
of New Hampshire and adjacent southwest Maine overnight. Lows
tonight should range from the 50s in the mountains...to a few
degrees either side of 60f for the remainder of the forecast area.
On Sunday...the weak disturbance attempts to inch northeast into
the stubborn high parked over the Maritimes. The onshore flow may
contribute to some patchy drizzle near the coast from Casco Bay
southward...otherwise the shower activity should be confined
largely to southern New Hampshire and extreme southwest Maine
during the day. High temperatures should be mainly in the 70s.
Long term /Sunday night through Friday/...
a upper level trough will approach the area through
Tuesday...then gradually move offshore Tuesday night. As the
trough moves east of the area, an upper ridge will start to build
across the region for the upcoming week. A cold cold front will
approach the region Friday and is expected to cross the area
Models continue to have differences in the progression of these
systems with the European model (ecmwf) being the most progressive. Although
the forecast is based on a blend of models, have put a bit more
weight in the slower model solutions. In addition, these models
tend to keep the more significant rainfall west and north of the
region...although all areas should see at least light amounts
Monday and Monday night.
In terms of surface conditions, damp weather will continue
through Tuesday as a persistent southeast flow gradually backs to
the east and northeast as a weak area of low passes very slowly
south of the Gulf of Maine on Tuesday. The combination of this low
along with high pressure over the Maritimes will lead to a bit of
cold air damming east of the mountains with high temps Monday and
Tuesday mainly in the 70s.
As the low moves away from the area Tuesday night and
Wednesday..a weak area of high pressure will build into the area.
The high will move offshore Wednesday night. As it does, a
southwest flow will bring warming temperatures and increasing
humidity into the region for Thursday and Friday.
Aviation /06z Saturday through Wednesday/...
short term /through Sunday/...LCL IFR through 11z in patchy
stratus and fog...otw VFR. LCL IFR developing aft 05z sun in
stratus and fog. Aft 12z sun...bcmg VFR with areas of MVFR in
Long term...areas of MVFR in showers Sunday night through Tuesday.
Otherwise mainly VFR conditions.
short term /through Sunday/...conditions to remain below Small Craft Advisory
thresholds through the period.
Long term...winds and seas expected to be below sca criteria
Monday through Thursday.