FXUS61 KGYX 100810
Area Forecast Discussion
National Weather Service Gray ME
410 AM EDT Fri Apr 10 2020
A strong storm system will exit into the Maritimes by late
today, leaving behind cooler temperatures, gusty winds and
a few rain and snow showers. High pressure returns on Saturday
with temperatures running above normal this weekend. The next
system arrives Monday with heavy rainfall and gusty winds possible.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Classic spring snowstorm is curling into the Canadian Maritimes
this morning leaving a trail of heavy...wet snow and power
outages in its wake.
The upper low will remain overhead for the first part of the
day...but S/WV trof diving thru the OH River Valley will help to
swing the larger trof axis across the forecast area from N to S
this afternoon. Given the cold pool aloft...lapse rates will be
quite steep...and any amount of heating today will make it
favorable for convection to develop. Along and ahead of the trof
axis convection allowing models develop a band of showers that
will quickly sweep thru the Srn half of the forecast. Temps will
be warm enough that this should mainly fall as rain. That being
said those cool temps aloft will support the potential for
small hail or graupel with the heaviest showers...in addition to
a few claps of thunder. I have added some thunder wording to
the forecast but opted to keep hail out of the grids for now.
Winds may also be quite gusty this afternoon as well. W flow
will mix deeply and tap winds around 40 kts at the top of the
boundary layer. This should be good enough for some 30 to
perhaps 35 kt wind gusts across much of the Srn half of the
.SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/...
Cyclonic flow continues thru Sat in the wake of departing low
pressure. Overall that will keep temps a little below normal and
mostly dry offshore flow. There will be upslope showers in the
higher terrain...especially across NH where W flow will be
closer to orthogonal to the ridgelines. Additional light
accumulations are possible in the higher terrain.
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
The ensemble and deterministic model solutions are in decent
agreement on the long wave pattern through late next week. The
active weather pattern will continue as troughing dominates here
in the east. Digging shortwave energy across the Pacific
northwest will carve out a deep upper trough over much of the
western CONUS with briefly rising heights downstream across the
eastern third of the country. This should provide a brief stretch
of quiet weather Saturday night into Sunday along with seasonable
temperatures as a ridge of high pressure builds by to our south.
A lead southern stream impulse over northern Mexico will race
northeast Sunday night and Monday to the eastern Great Lakes where
it'll merge with a northern stream impulse and carve out an upper
low. At the surface...developing low pressure will track through
the Mississippi Valley and into the Great Lakes Late Sunday
through Monday. The trailing frontal system will cross the area
late Monday preceded by mild temperatures and periods of heavy
rain as thermal profiles from deterministic and ensemble solutions
support a liquid event. Cool cyclonic flow and a series of
passing impulses in the wake of this system will produce a few
clouds along with scattered rain or showers into mid week.
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
Short Term...For the most part conditions have improved to VFR
across much of the forecast area. Still some local IFR in -SN
across the mtns and shortly coming to an end across the
Midcoast. There will be scattered SHRA/SHSN today with local
MVFR or lower at times...but confidence is a little too low in
any one location to put as prevailing in the TAFs. Hi-res
guidance is starting to converge towards a line of SHRA perhaps
with some TSRA across the Srn half of NH and adjacent Wrn ME.
This will sweep S during the mid afternoon. Otherwise VFR
conditions will prevail thru Sat S of the mtns...with a stay
SHSN possible at HIE into Sat.
Mon...IFR in RA and fog with sfc winds gusting to 25 kt.
Tue...Areas of MVFR in cig with sct -SHRA and mtn -SHSN.
Short Term...Gale warnings continue for all waters as CAA
commences across the region in the wake of departing coastal
storm. While winds may lull this morning...they are expected to
increase again during the day. Winds will be slow to
diminish...with SCA conditions likely on all waters into Sat.
Sun...SCA's possible outside the bays.
Tue...SCA's likely...with gales possible outside the bays.
Another system will cross the region on Monday with heavy rain
and snow melt pushing some rivers and streams to bankfull.
The last GYX upper air observation was March 25 at 12Z.
Unfortunately, a disruption in gas supply has temporarily halted
observations from GYX. At this time it is unknown when
observations will resume.
The Sugarloaf NWR transmitter has returned to service.
ME...Winter Storm Warning until 2 PM EDT this afternoon for
NH...Winter Storm Warning until 2 PM EDT this afternoon for NHZ001-
MARINE...Gale Warning until 11 AM EDT this morning for ANZ150>154.
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