Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
1133 am EDT sun may 24 2015
high pressure shifts to our south today and will will provide
fair and warmer weather into Memorial Day. A warm front will
cross the areas Monday night and Tuesday....providing a chance for
showers and storms. Warm and more humid conditions are expected
middle to late week.
Near term /until 6 PM this evening/...
have updated forecast based on current conditions and latest set
of mesoscale models. Frontal boundry forming over northern New
Hampshire and west-central Maine this morning. A weak impulse will
enter the region in a northwest flow as instability slowly
increases this afternoon. Cape values climb to around 500 j/kg in
the area of frontogenesis.
Based on above...have increased the cloud coverage for today and
increased probability of precipitation to chance or slight chance over the northeastern
half of our forecast area. The showers and isolated rumbles of
thunder will likely dry up when attempting to reach southwestern
portions of the forecast area.
Temperatures climbing faster than anticipated...but clouds will
inhibit readings somewhat this afternoon. Nevertheless...some
areas to peak out at 80 degrees today over southernmost areas.
update...a few minor changes based on current
observational trends. Could be a sprinkle in northern zones this
morning...as shortwave trough crosses just north of the international border.
Previous discussion...as high pressure settles S of New England...westerly
return flow will help to warm up the forecast area nicely today.
Widespread 70s are expected...with pockets of 80s from kash to
kcon and eastward to ksfm. Despite the advection of higher dewpoints
than yesterday...the warm temperatures will offset that and keep relative humidity
values below 30 percent. Continued gusty westerly winds will mean fire
danger will stay elevated for at least another day.
A northern stream shortwave trough will brush the forecast area later
today...and may help trigger a few showers across the northern zones.
Mesoscale model forecasts favor enough graupel development for
some isolated thunder...so have also added this to the forecast.
Short term /6 PM this evening through 6 PM Monday/...
return flow continuing overnight will keep temperatures much milder than
the past couple of nights. By Monday a warm front will try and lift
through the forecast area. Increasing dewpoints from the SW advecting
over the cold Gulf of ME will likely support low stratus
development. At this time wind direction looks to keep that mostly
offshore...but will have to monitor towards the end of the period.
Another feature to watch will also be late day convection across
the upper Midwest today. Model forecasts show an area developing
and moving northeastward into the Great Lakes overnight. Some of the more
aggressive forecasts...like the GFS...bring this over the ridge
and into parts of New England for Monday. For now have increased pop
in the mountains during the day.
Long term /Monday night through Saturday/...
large 500mb ridge builds in early in the week and overruns closed
low to the south setting up Rex block through the end of the
week...leading top a warm and humid conditions into early next
Initially on Monday night a weak wave rides over the top of the
ridge and pushes low-middle level warm front SW-NE through the area. As
is often the case as the wave encounters the ridge it flattens out
and dynamics weaken as the warm air advection moves through. So best chance of of any
rain showers/thunderstorms and rain will be in the northern and western zones...with coastal areas
only see a slight chance of rain from this front. The front lingers
into Tuesday morning...but ridging builds quickly behind this front
and expect partial clearing at least and warming temperatures Tuesday
afternoon with highs 80-85 inland and 70s on the coast. With dew points
rising into the low-middle 60s. After a muggy Tuesday night with lows
mainly in the upper 50s to middle 60s...Wednesday looks to be the
warmest day of the week as highs climb securely in the 80s...with
a few spots in southern New Hampshire making a run at 90. A weak front moves in
from the northwest Wednesday afternoon...but the trend is for it to stall or
wash out before it reaches the County Warning Area...at least according to the 00z
Euro. Still could set off some some convection in the mountains
For Thursday-Sat we will be sitting on the anticyclonic side of the 500
mb jet...and will have to watch fro some waves moving through the
flow. Which could set off rain showers/thunderstorms and rain at least one day during that
timeframe...but models are not consistent enough with any feature
to nail down these waves at this time. It will stay warm and humid
through this period with highs low-middle 80s inland and in the 70s on
Aviation /16z Sunday through Thursday/...
short term...VFR conditions to prevail through Monday. Gusty westerly winds
expected today...with gusts around 25 kts at times at all
terminals. There is the possibly that increasing moisture
advection over the waters will support some low stratus
development later Monday. This is a low confidence forecast at this
Long term...MVFR or IFR in showers is possible Monday
night...otherwise mainly VFR Tue-Thu. Scattered thunderstorms and rain are possible Wednesday
and Thursday afternoon..E.Specially away from the coast.
short term...overland temperatures are expected to warm nicely
today...allowing for deeper mixing near-shore. Occasional gusts of
25 kts are possible for the bays as a result. On the outer waters
the continued westerly flow will keep seas near 5 feet with gusts around
20 kts at times. Given the Holiday weekend and increased
recreation on the waters a Small Craft Advisory has been issued through this evening.
Long term...high pressure builds south of the waters this
week...but weak waves of low pressure will pass north of New England
and could enhance SW flow at times that winds/seas approach Small Craft Advisory
return flow will help increase dewpoints across much of the area
today. However...warming temperatures will keep relative
humidities below 30 percent. Gusty westerly winds will keep fire
danger elevated today. Highest temperatures and lowest relative
humidity values are expected across southern New Hampshire. By
Monday higher moisture in the air mass will keep relative
humidities above 30 percent...as a warm front lifts through the
area with scattered showers.
Marine...Small Craft Advisory until 8 PM EDT this evening for anz151-
Small Craft Advisory until 2 am EDT Monday for anz150-152-154.