Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
628 PM EDT Sat Apr 25 2015
upper level low pressure continues to wobble around over Maine
and the Canadian Maritimes through Tuesday....and the cool and
showery weather continues. The low will finally shift east
allowing high pressure to build in on Wednesday. Low pressure
passes south of the area Thursday...with high pressure building
back in behind it.
Near term /through Sunday/...
630pm update... just some minor adjustments. Forecast is on track.
Another weak impulse rotates southward around the closed low to our east
late this afternoon...and this is setting off some light
rain showers/shsn in the mountains and foothills. Should be enough downslope to
prevent any measurable precipitation from making it onto the coastal
plain...but could see a spkl/flry...mainly in the Kennebec and
Penobscot valleys through about sunset. Otherwise...look for some
clearing this evening in the downslope areas...with clouds holding in
the mountains mins drop back into 30s tonight...around 40 on the coast
and in the population centers of southern New Hampshire.
Short term /Sunday night through 6 PM Sunday/...
another wave rotates southward around that closed low on Sunday and
pulls the low back a little bit to the west...so expect more
passing showers on Sunday than we saw on Saturday...but still
will be more of the hit or miss variety. Also temperatures aloft will be
warming so any shsn will be limited to the higher terrain...and
temperatures will rise a couple degrees warmer than today. Once
again...shaved a few degrees off maxes in the mountains...as guidance
was too warm for the second day in a row.
A stronger wave begins to shift SW around the top of the low Sun
night...and the threat for more widespread rain showers moves in toward
daybreak...with lows again in the 30s to around 40.
Long term /Sunday night through Saturday/...
the models are in only fair agreement on the long wave pattern
through late next week. So confidence in sensible weather details diminishes
by middle week. We begin the period with the upper low meandering
just to our east. By Wednesday...the upper low may lift far enough
offshore for weak ridging to take hold and provide a dry warm day.
By late Thursday...the next northern stream impulse and an
associated cold front should approach the area before sliding
offshore on Friday. Another weak impulse could bring a few clouds
and scattered showers Saturday. Ridging and warm temperatures
follow to round out the weekend.
Aviation /22z Saturday through Thursday/...
short term...VFR conditions will prevail through Sunday
evening...although could see some MVFR in shsn at khie into this
evening. Could see MVFR to IFR ceilings move in later Sun night.
Monday - Tuesday...scattered MVFR possible in showers.
Friday...scattered MVFR possible in showers.
short term...weak low pressure near the waters will keep
winds/seas well below Small Craft Advisory criteria through Sun night.
Tuesday and Friday...small craft winds and seas are possible.
despite dry conditions over southern New Hampshire and SW ME...relative humidity values will be
on the rise Sunday and Monday...as will be the threat of rain showers.
Winds will also be light through the period...generally 10 miles per hour or